Saturday, 9 May 2020

Plant structure ( Morphology and Anatomy)


In this article, we are providing information about plant structure include anatomy and morphology, you can also know cell wall structure and more. The state of the plant is very diverse, not only among its many phyla but also within species. Many of these have become extinct, with distinct distinctions in the body parts of the oldest vascular plants such as roots and leaves.


Figure. Morphological plant structure.

The presence of these organs reflects increased specialization, especially among modern vascular plants in relation to the demands of terrestrial existence. Obtaining water, for example, is a major challenge, and roots are adapted for water absorption from the soil. Leaves, roots, branches, and flowers all vary in size from plant to plant.
The development of the plant structure can be precisely controlled as these parts, but some aspects of leaf, stem, and root development are quite flexible. This article emphasizes the integrated aspects of plant form, using a flowering plant as a model.

Vascular plants have roots and shoots

The avascular plant has a root system and a pellet system. Among their tips are roots and shoots, called apes.
The root system anchors the plant and enters the soil, allowing it to absorb water and ions to nourish the plant. Root systems are often widespread, which can produce great strength to advance growing roots. Roots evolved later than the shoot system as an adaptation to living on land.

Structure of plant cell wall

Figure. Anatomy structure of plant cell wall.

The shoot system consists of leaves and stems. The major sites of photosynthesis serve as a scaffold for the position of the stem leaves, the arrangement, shape, and other characteristics of the leaves are important in the production of plant food. Flowers, other reproductive organs, and ultimately, fruits and seeds are also formed on the shoot.

The repeating unit of the vegetative shoot consists of the internode, node, leaf, and axillary bud, but not reproductive structures. An axillary bud is the latest shoot apex that allows the plant to replace a branch or main shoot if it is eaten by a shepherd. A vegetative axillary bud has the capacity to replace the primary shoot. When the plant is transferred to the reproductive stage of development, these axillary buds can produce flower shoots.

The root and the shoots are made up of three types of tissue

Plant cell types can be distinguished by the size of their vacuoles, whether they are living or not at maturity, and by the thickness of their cellulose cell walls, a distinguishing feature of plant cells. Some cells have only a primary cell wall of cellulose, synthesized by the protoplast near the cell membrane. Microtubules align within the cell and determine the orientation of the cellulose fibers. Cells that support the plant body have more heavily reinforced cell walls with multiple layers of cellulose and other strengthening molecules, including lignin and pectin. Cellulose layers are laid down at angles to adjacent layers like plywood; this enhances the strength of the cell wall.

The sprouts, roots, and leaves all have three types of basic tissue: ground, dermal, and vascular tissue. Because each of these tissues extends through the root and shoot systems, they are called tissue systems. In most plants, the cell layer of the epidermis, and cutaneous tissue is thick, and it forms an outer protective covering for the plant. Ground tissue cells perform storage, photosynthesis functions in addition to supporting plants and making protective fibers. Vascular tissue carries fluids and dissolved substances throughout the body. Each of these issues and their many functions are described in more detail in later sections.

New growth occurs at meristems

When a seed sprout, only a tiny portion of the adult plant exists. Although embryonic cells can undergo division to form many types of cells, most adult cells are more restricted. The development of the plant body is based on the activity of shoots and root apices as well as properties found in other parts of the plant. depends on. Meristem cells are indifferent which can divide indefinitely and give rise to many differentiated cells.

Overview of meristems

Meristems are clusters of small cells with dense cytoplasm and proportionately large nuclei that act as stem cells do in animals. One cell divides to give rise to two cells, one of which remains meristematic, while the other contributes to the body of the plant. In this way, cells of the meristem continuously renew. 

 Meristem cell division

Figure.  Meristem cell division.

Molecular genetic evidence supports the hypothesis that animal stem cells and plant meristem cells may share some of the commonest of gene expression. For example, both plant meristem and animal stem cells share the Retinoblastoma gene, which determines whether a cell continues dividing or differentiates. The expanding cell of both the root and shoot results in repeated divisions and subsequent elongation of the cells produced by the epistemic merge. In woody plants, lateral meristems produce an increase in root and shoot diameter.

Apical meristems

The apical meristem and roots are located at the tips showing in this anatomy structure diagram. The cells of the epistemic meristem divide, during the period of development, and continuously add more cells to the tips. The tissues derived from the apical meristems are called primary tissues, the expansion of the root and stem is known as the primary plant body structure. Some plants have young, soft sprouts and a tree body in the primary plant body. Both the root and shoot apical meristems are made up of fragile cells that need protection. The root apical meristem is protected by the root cap, the anatomy of which is described in section 36.3. Root meristem cells are formed by the root cap, closed and transferred to the root through the soil. In contrast, the leaf primordia give rise to the shoot apical meristem, which is particularly susceptible to desiccation due to exposure to air and sun.

 Apical meristems

Figure. Anatomy structure of Apical meristems.

The apical meristem gives rise to the three tissue systems by first initiating primary meristems. The three primary meristems are the protoderm, which forms the epidermis; the procambium, which produces primary vascular tissues (primary xylem for water transport and primary phloem for nutrient transport); and the ground meristem, which differentiates further into ground tissue. In some plants, such as horsetails and corn, intercalary meristems arise in stem internodes (spaces between leaf attachments), adding to the internode lengths. If you walk through a cornfield on a quiet summer night when the corn is about knee-high, you may hear a soft popping sound. This sound is caused by the rapid growth of the intercalary meristems. The amount of stem elongation that occurs in a very short time is quite surprising.

Lateral meristems

Many herbaceous plants (that is, plants with fleshy, not woody, stems) exhibit only primary growth, but others also exhibit secondary growth, which may result in a substantial increase of diameter. In anatomy structure of Secondary growth is accomplished by the lateral meristems—peripheral cylinders of meristematic tissue within the stems and roots that increase the girth (diameter) of gymnosperms and most angiosperms. Lateral meristems form from ground tissue that is derived from apical meristems. Monocots are the major exception.

Although secondary growth increases girth in many nonwoody plants, its effects are most dramatic in woody plants, which have two lateral meristems. Within the bark of a woody stem is the cork cambium—a lateral meristem that contributes to the outer bark of the tree. Just beneath the bark is the vascular cambium—a lateral meristem that produces secondary vascular tissue. The vascular cambium forms between the xylem and phloem in vascular bundles, adding secondary vascular tissue to both of its sides. Xylem is added to the inside of the vascular cambium, and the phloem is added to the outside.

Apical and lateral meristems.

Figure. Anatomy structure of Apical and lateral meristems.

In this anatomy structure, Secondary xylem is the main component of wood. Secondary phloem is very close to the outer surface of a woody stem. Removing the bark of a tree damages the phloem and may eventually kill the tree. Tissues formed from lateral meristems, which comprise most of the trunk, branches, and older roots of trees and shrubs, are known as secondary tissues and are collectively called the secondary plant body.

Friday, 24 April 2020

Basic Structure and Function of DNA

DNA, Chromosomes, and genomes

The ability of organisms necessary to sustain life depends on the ability of cells to store and translate by translating and retrieving genetic instructions. This hereditary information is passed on from a cell to its daughter cells at cell division, and from one generation of an organism to the next through the organism’s reproductive cells. The instructions are stored within every living cell as its genes, the information-containing elements that determine the characteristics of a species as a whole and of the individuals within it.

As soon as genetics emerged as a science at the beginning of the twentieth century, scientists became intrigued by the chemical structure of genes. The information in genes is copied and transmitted from cell to daughter cell millions of times during the life of a multicellular organism, and it survives the process essentially unchanged. What form of a molecule could be capable of such accurate and almost unlimited replication and also be able to exert precise control, directing multicellular development as well as the daily life of every cell? And how can the enormous amount of information required for the development and maintenance of an organism fit within the tiny space of a cell?.

The answers to several of these questions began to emerge in the 1940s. At this time researchers discovered, from studies in simple fungi, that genetic information consists largely of instructions for making proteins. Proteins are phenomenally versatile macromolecules that perform most cell functions. They serve as building blocks for cell structures and form the enzymes that catalyze most of the cell’s chemical reactions. They also regulate gene expression and they enable cells to communicate with each other and to move The properties and functions of cells and organisms are determined to a great extent by the proteins that they are able to make.

Painstaking observations of cells and embryos in the late nineteenth century had led to the recognition that the hereditary information is carried on chromosomes—threadlike structures in the nucleus of Light microscopy that makes a cell visible by eukaryotic as soon as the cell begins to divide. Later, when the biochemical analysis was possible, the chromosomes were found to contain deoxyribonucleic acid DNA and protein, both of which were present in approximately equal amounts. For many decades, DNA was considered only a structural one. However, the other crucial advance made in the 1940s was the identification of DNA as the likely carrier of genetic information. This breakthrough in our understanding of cells came from studies of inheritance in bacteria.

But still, as the 1950s began, both how proteins could be specified by instructions in the DNA and how this information might be copied for transmission from cell to cell seemed completely mysterious. The puzzle was suddenly solved in 1953 when James Watson and Francis Crick derived the mechanism from their model of DNA structure. The determination of the double-helical structure of DNA immediately solved the problem of how the information in this molecule might be copied, or replicated. It also gave the first clue as to how DNA uses a sequence of its subunits to form a molecule protein and encode a directive. Today, the fact that DNA is the genetic material is so fundamental to biological thought that it is difficult to appreciate the enormous intellectual gap that was filled by this breakthrough discovery.

The DNA structure of the chemical properties of DNA makes it ideally suited as the raw material of genes. This DNA arranges how many proteins and packages in chromosomes. The packing has to be done in an orderly fashion so that the chromosomes can be replicated and apportioned correctly between the two daughter cells at each cell division. And it must also allow access to chromosomal DNA, both for the enzymes that repair DNA damage and for the specialized proteins that direct the expression of its many genes.

In the past two decades, there has been a revolution in our ability to determine the exact order of subunits in DNA molecules. As a result, we now know the sequence of the 3.2 billion nucleotide pairs that provide the information for producing a human adult from a fertilized egg, as well as having the DNA sequences for thousands of other organisms. Detailed analyses of these sequences are providing exciting insights into the process of evolution.

This is the first of four chapters that deal with basic genetic mechanisms—the ways in which the cell maintains, replicates, and expresses the genetic information carried in its DNA. We shall discuss the mechanisms by which the cell accurately replicates and repairs DNA; we also describe how DNA sequences can be rearranged through the process of genetic recombination. Gene expression—the process through which the information encoded in DNA is interpreted by the cell to guide the synthesis of proteins—is we describe how this gene expression is controlled by the cell to ensure that each of the many thousands of proteins and RNA molecules encrypted in its DNA is manufactured only at the proper time and place in the life of a cell.

The Structure and Function of DNA

The molecule seemed too simple: a long polymer composed of only four types of nucleotide subunits, which resemble one another chemically. In the early 1950s, by X-ray analysis of DNA, a technique for determining the three-dimensional atomic structure of a molecule. Initially X-ray diffraction results in two strands of DNA polymer lesion formed in the helix. The observation that DNA was double-stranded provided one of the major clues that led to the Watson–Crick model for DNA structure that, as soon as it was proposed in 1953, made DNA’s potential for replication and information storage apparent.

The nucleotide DNA molecule has two complementary chains

Deoxyribonucleic acid (DNA) the molecule consists of two long polynucleotide chains composed of four types of nucleotide subunits. The chains run antiparallel to each other, and hydrogen bonds between the base portions of the nucleotides hold the two chains together nucleotides are composed of a five-carbon sugar to which are attached one or more a nitrogen-containing based and phosphate groups. Among nucleotides, a single phosphate group is deoxyribose attached to sugar, and its base may be either adenine (A), cytosine (C), guanine (G), or thymine (T). Nucleotides are covalently linked together in a series of phosphates and sugars, which thus "sugar" the sugar-phosphate-sugar-phosphate alternatively. Because only the base differs in each of the four types of nucleotide subunit, each polynucleotide chain in DNA is analogous to a sugar-phosphate necklace (the backbone), from which hang the four types of beads the bases A, C, G, and T. These same symbols A, C, G, and T) are commonly used to denote either the four bases or the four entire nucleotides—that is, the bases with their attached sugar and phosphate groups.
Building blocks of DNA diagram
Fig. DNA and its building blocks

The way in which the nucleotides are linked together gives a DNA strand a chemical polarity. If we think of each sugar as a block with a protruding knob (the 5 ʹ phosphates) on one side and a hole (the 3 ʹ hydroxyls) each completed Interlocking series with holes made by knobs, all of its subunits will be lined up in the same orientation.  Moreover, the two ends of the chain will be easily distinguishable, as one has a hole (the 3 ʹ hydroxyls) and the other a knob (the 5 ʹ phosphates) at its terminus. This polarity in a DNA chain is indicated by referring to one end as the 3 ʹ ends and the other as the 5 ʹ ends, names derived from the orientation of the deoxyribose sugar. With respect to DNA’s information-carrying capacity, the chain of nucleotides in a DNA strand, being both directional and linear, can be read in much the same way as the letters on this page.
DNA Complementary base pairs diagram

Fig.  Complementary base pairs in the DNA double helix.


The three-dimensional structure — the double helix of DNA — arises from the structural and chemical characteristics of its two polynucleotide chains. Because the two chains are held together by hydrogen bonding based on different strands, all the bases are inside the double helix, and the sugar-phosphate backbones are paired with a single-ring base (a pyrimidine): A always pairs with T, and G with C.This complementary base-pairing enables the base pairs to be packed in the interior of the double helix has the most energetically friendly arrangement. In this arrangement, each base pair is of similar width, thus holding the sugar-phosphate backbones a constant distance apart along the DNA molecule. To maximize the efficiency of base-pair packing, the two sugar-phosphate backbones wind around each other to form a right-handed double helix, with one complete turn every ten base pairs.

The members of each base pair can fit together within the double helix only if the two strands of the helix are antiparallel—that is, only if the polarity of one Is oriented opposite to the other strand. A consequence of DNA’s structure and base-pairing requirements is that each strand of a DNA molecule contains a sequence of nucleotides that is exactly complementary to the nucleotide sequence of its partner strand.

DNA structure for the mechanism of heredity

The discovery of the structure of DNA immediately suggested answers to the two most fundamental questions about heredity. First, how could the information specify an organism be carried in a chemical form? And second, how could this information be duplicated and copied from generation to generation?
The answer to the first question came from the realization that DNA is a linear polymer of four different kinds of monomer, strung out in a defined sequence like the letters of a document written in an alphabetic script.

The answer to the second question came from the double-stranded nature of the structure: because each strand of DNA contains a sequence of nucleotides that is exactly complementary to each strand can serve as a template for the synthesis of a strand complementary to the nucleotide sequence of its new partner strand. In other words, if we designate the two DNA strands as S and S ʹ, strand  S can serve as a template for making a new strand S ʹ, while strand S ʹ can serve as a template for making a new strand S.Thus, the genetic information in DNA can be accurately copied by the beautifully simple process in which strand S separates from strand S ʹ, and each separated strand then serves as a template for the production of a new complementary partner strand that is identical to its former partner.
DNA double helix diagram

Fig. The DNA double helix

The ability of each strand of a DNA molecule to act as a template for producing a complementary strand enables a cell to copy or replicate, its genome before passing it on to its descendants. We shall describe the elegant machinery that the cell uses to perform this DNA. Before determining the structure of DNA, genes contain instructions for the production of proteins. If genes are made of DNA, the DNA must therefore somehow encode proteins. A protein that is responsible for a biological function is characterized by its three-dimensional structure. This structure is determined in turn by the linear sequence of the amino acids of which it is composed. The exact correspondence between the four-letter nucleotide alphabet of DNA and the twenty-letter amino acid alphabet of proteins—the genetic code—is not at all obvious from the DNA structure. We will describe this code in detail in the course of elaborating the process of gene expression, through which a cell converts the nucleotide sequence of an RNA molecule first consists of genes, then an amino acid sequence of the protein.
 Duplication of DNA diagram

Fig. DNA as a template for its own duplication


The complete store of information in an organism’s DNA is called its genome, and it specifies all the RNA molecules and proteins that the organism will ever synthesize. The amount of information contained in genomes is staggering. The nucleotide sequence of a very small human gene, written out in the four-letter nucleotide alphabet, while the complete sequence of nucleotides in the human genome would fill more In addition to other critical information, it includes roughly 21,000 protein-coding genes, which give rise to a much greater number of distinct proteins.

In Eukaryotes, DNA Is Enclosed in a Cell Nucleus

Nearly all the DNA in a eukaryotic cell is sequestered in a nucleus, which in many cells occupies about 10% of the total cell volume. This compartment is delimited by a nuclear envelope formed by two concentric lipid bilayer membranes. These membranes are punctured at intervals by large nuclear pores, through which molecules move between the nucleus and the cytosol. The nuclear envelope is directly connected to the extensive system of intracellular membranes called the endoplasmic reticulum, which extends out from it into the cytoplasm. And it is mechanically supported by a network of intermediate filaments called the nuclear lamina—a thin feltlike mesh just beneath the inner nuclear membrane.
The nuclear envelope allows the many proteins that act on DNA to be concentrated where they are needed in the cell, and it also keeps nuclear and cytosolic enzymes separate, a feature that is crucial for the proper functioning of eukaryotic cells.

Wednesday, 15 April 2020

antibiotic resistance


This enzyme is most important about natural products. Through which antibiotic resistance new antibiotics can be developed for the health of human life. Human health It was widely believed that there would no longer be a risk of serious bacterial infection. Bacterial diseases such as leprosy, pneumonia, others were being cured by the administration of antibiotics - compounds that kill bacteria in which they thrive without harming the human host. These have become increasingly resistant to "surprise drugs", as pathogenic bacteria cause many deaths that were once successful.

Which almost disappeared from developed countries, even tuberculosis is referred to worldwide as XDR extremely drug-resistant which is virtually untreated. A major XDR-TB is on the verge of becoming a global health crisis. There has been a drastic reduction in resources for the development of new antibiotics in this pharmaceutical industry.

This change of action is attributed by the pharmaceutical industry

(1) Antibiotics are only taken for a short period of time for chronic conditions such as diabetes - lack of financial incentives.

(2) New antibiotics with a relatively short lifespan in the market as bacteria become resistant to each successive product. 

(3) The most effective antibiotics are being widely used and as a last resort if other medicines are not successful.

The idea of ​​the formation of non-institutions for the new development has been widely considered by many antibiotics.

The action of antibiotics specifically targets enzymes that most antibiotics derive from natural products in the development of bacterial resistance, which is manufactured by microorganisms to kill other microorganisms. Bacteria have been shown to be weak in many ways.

These include the following:

1. Enzymes are involved in the synthesis of the bacterial cell wall 

Penicillin and its derivatives, such as methicillin, are structural analogs of the substrate of the peptidases of Tran that catalyze the final cross-linking reactions that toughen the cell wall. If these reactions do not occur, a rigid cell wall does not succeed in developing. Penicillin is an irreversible inhibitor of transpeptidases; The antibiotic is in the active site of these enzymes, forming a covalently bound complex that cannot be degraded. Vancomycin, an antibiotic originally derived from Borneo, was derived from a microorganism living in soil samples by inhibiting peptization of Tran by binding to the peptide substrate of the enzyme transpeptidase. Trans peptidase typically, the substrate terminates in a D-melanin-D-allene dipeptide.

To become vancomycin-resistant, a bacterial cell must synthesize an alternative terminus that does not bind the drug, a rounding process requiring several new enzymatic activities. Vancomycin antibiotics in which bacteria are able to develop minimal resistance and thus are given last resort when other antibiotics are not successful. Vancomycin-resistant to many pathogenic bacteria including Staphylococcus aureus has emerged in a few years. Aureus skin and nasal passages are relatively harmless, the organism causing life-threatening infections that develop in hospitalized patients who have open wounds or invasive tubes. Methicillin-resistant aureus (MRSA), causing thousands of patients to die. MRSA infections are also beginning to appear in community settings, such as high school gyms or children's day-care centers. In many cases, vancomycin is the only drug that can prevent these infections. 

Obtaining a cluster of MRSA vancomycin showed that Maybe resistant, a gene resistant to another bacterium face, a common cause of hospital-based infections. So far, no known vancomycin-resistant MRSA has been able to gain a foothold in either a hospital or community setting, but it may only be a matter of time. Infectious disease specialists, for this reason, have isolated patients from hospitals to establish better hygiene programs and at the first sign of infection. These have been proven to reduce the occurrence of fatal infections where they are kept in place.

2. Components of the system by which bacteria transcribe, duplicate and Translate their genetic information 

Eukaryotic and bacterial cells have a system for storing and using genetic information, which are the many differences between the two types of cells that pharmacologists can take advantage of. Streptomycin and the Tetracycline’s, for example, bind to bacterial ribosomes, but not eukaryotic ribosomes. This is a rare example of fully synthetic antibiotics. Quinolones, such as ciprofloxacin brand name Cipro, inhibit the quinolone enzyme DNA gyrase, which is required for bacterial DNA replication.

Almost all of the new compounds present in antibiotics are derivatives that have been chemically modified in the laboratory. New compounds are tested in two ways. The compound is tested for its ability to kill bacterial cells that bind to and inhibit a laboratory-specific target protein that has been purified from bacterial cells. It was hoped that the genome sequencing of pathogenic bacteria starting in 1995 is the new drug target.

There are only two new classes of antibiotics specifically developed and developed since 1963. One of these classes includes the antibiotic linezolid introduced in 2000, which acts specifically on bacterial ribosomes and interferes with protein synthesis. The other new class of antibiotics, introduced in 2003 and represented by distamycin are cyclic lip peptides, which disrupt bacterial membrane function. Many researchers are hoping that Zibo and Cubic will be used sparingly so that resistance can be kept to a minimum.

3. Bacteria that specifically catalyze metabolic reactions in enzymes

Sulfa drugs are effective antibiotics, as they are similar to the compound p-aminobenzoic acid (PABA), एफ़
antibiotic resistance

for example, which bacteria necessarily convert to coenzyme folic acid. Since humans lack a folic acid-synthesizing enzyme, they must obtain this essential coenzyme in their diet and, consequently, sulpha drugs have no effect on human metabolism.

Tuesday, 14 April 2020

whole-genome sequencing


Development of molecular biology DNA whole-genome sequence is the basis pair of highly automated and useful for DNA analysis sequencingThe ultimate physical map is the base-pair sequence of an entire genome. In the early days of molecular biology, all sequencing was done manually, and was, therefore, both time- and labor-intensive the development of machines to automate this process increased the rate of sequence generation.

On a larger scale, it is useful for high-automated computer analysis and sequencing for genome sequencing. One such genome sequencing, which baffles technology science, in a few hours, an automated Sanger sequencer can sequence the same number of base-pairs that a technician can manually sequence up to 50,000 bp a year. With the current generation of sequencing technology described in the previous chapter, the rate of sequence generation is now five orders of magnitude greater than when the human genome was sequenced with automated Sanger sequencers. 

Genome sequencing requires larger molecular clones

To isolate DNA from an organism, it would be ideal to add in a sequencer, then in a week or two to take a computer-generated printout of the genome sequence, a process that is not straightforward. Sequencers for DNA segments provide precise sequences of up to 800 bp. However, errors are possible. To reduce errors, each causal clone can be sequenced 5–10 times.


Artificial chromosomes

The development of artificial chromosomes of DNA has allowed scientists to clone large fragments. The first generation of these new vectors were yeast artificial chromosomes (YACs). The centromere sequence and they are constructed using the origin of replication, then foreign DNA is added to it. The origin of this replication is allowed to replicate independently of the rest of the artificial chromosome genome, and the centromere sequences make the chromosome stable.

YACs are used to clone large pieces of DNA, they had several drawbacks, including the tendency to rearrange portions of DNA by deletion. Despite these difficulties, YAC was used for physiological construction by restriction enzyme digestion of YAC DNA.

Artificial chromosomes are most commonly used in E-coli, especially for large-scale sequencing. These bacterial synthetic chromosomes (BACs) accept bacterial DNA plasmid BAC vectors between 100 and 200 km of DNA inserts. The downside of BAC vectors is that, like chromosomes, bacteria are kept as one copy while plasmid vectors are present in high copy numbers.


Human artificial chromosomes

Human DNA can present in cells from large areas of the human artificial chromosome. These artificial chromosomes are usually constructed by fragmentation of chromosomes with centromere sequences. Some circulars may still separate correctly during mitosis up to 98% of the time. The construction of linear human artificial chromosomes is not yet possible.

Whole-genome sequencing is approached in two ways: clone-by-clone and shotgun

Sequencing an entire genome is an enormous task. Two ways of approaching this challenge have been developed: one that approaches the sequencing one step at a time, and another that attempts to take on the whole thing at once and depends on computers to sort out the data. The two techniques grew out of competing projects to sequence the human genome.

Clone-by-clone sequencing

The cloning of large inserts in BACs facilitates the analysis of entire genomes. Creating a physical map, and then a strategy commonly adopted for subsequent sequencing is used to place the site of the first BAC clones.

Clone-by-clone sequencing

Figure. The clone-by-clone method uses large clones assembled into overlapping regions by STSs. Once assembled, these can be fragmented into smaller clones for sequencing.

To align a large part of the chromosome it is necessary to identify regions that overlap between clones. This can be accomplished by constructing each BAC clone either a restriction map or identifying STs found in the clone. If the two STs in the BAC clone are identical, it will be necessary to overlap them.

Alignment of a number of BAC clones Accidentally there is a sudden stretch of DNA. personally, BAC clones can be assigned to a sequence of 500 bp at a time that the entire comb sequence can be formed. The latter sequencing is called physical clone-by-clone sequencing.

Shotgun sequencing

The idea of shotgun sequencing is simply to randomly cut the DNA into small fragments, sequence all cloned fragments, and then use a computer to put together the overlaps. This actually occurs in the early days of molecular cloning when the creation of a library of fragmented fragments was called shotgun cloning. This approach is much less compared to the clone-by-clone method but requires much more computer power to assemble the final sequence and be a very efficient algorithm for finding overlap.

Shotgun sequencing

Figure. In the shotgun method, the entire genome is fragmented into small clones and sequenced. Computer algorithms assemble the final DNA sequence based on overlapping nucleotide sequences.

Shotgun sequencing does not tie the sequence to any other information about the genome, unlike the clone-by-clone approach. Many investigators have used both clone-by-clone and shotgun-sequencing techniques, a hybrid approach that builds the strength to bind sequences to a physical map in this combination, while greatly reducing the time involved.

An assembler program that compares multiple copies of indexed regions to assemble a sequence, but one sequence that matches all copies. Because computer assemblers are incredibly powerful, the ultimate requirement for the human analysis is to determine after both shotgun sequencing and clone-by-clone when a genome sequence is sufficient to be useful to researchers.

The Human Genome Project used both sequencing methods


Initiated a new way of conducting biological research involving large teams of genomics on a large scale. But a single individual can isolate and manually sequence molecular clones for a single gene, a collaborative effort by researchers from hundreds of large genomes, such as the human genome.

The Human Genome Project began in 1990 by a group of American scientists when the International Human Genome Sequencing Consortium was formed. Funded were publicly using a clone-by-clone approach to target sequences of the human genome. Sequences of each chromosome were used as physical and genetic maps.

In May 1998, Craig Venter, whose research group had sequenced Haemophilus influenza, announced his private company (Celera Genomics) would sequence the human genome. In two years he proposed only the 3.2-gigabyte genome shotgun-sequence. The association raced to challenge and introduce human genome sequencing. In contrast, there was a tie. On 26 June 2000, the groups jointly declared success, and all published their findings together in 2001.

The association consisted of 248 authors. The sequence of the human genome was still early. Gaps are being filled in the sequence, and the map is constantly being refined. The "finished" human sequence is 400-fold deficient by only 260 intervals, and now includes 99% of euchromatic sequences, with an error rate of 100,000 references per sequence in terms of 95%. New sequencing techniques are being used to shut down. Remaining interval. A few individuals, including James Watson who co-discovered the structure of DNA, have now had their personal genomes sequenced. The cost of having one’s genome sequenced is predicted to fall to $1000 in the next few years, raising many questions about genome privacy.

Sunday, 5 April 2020

The study of Indian foreign policy

The Indian Foreign Policy

The purpose of this article is to study the concepts, methods, and principles of contemporary Indian foreign policy and foreign policy subjects. Foreign policy analysis (FPA) and international relations (IR) closer together. We want to tackle two shortcomings by studying IR and FPA. First, so far most of the western countries are focused on matters, while little attention is paid to the principle of Indian foreign policy. Second, the two disciplines have been dominated by Western-born concepts and their methods. It is only those notable works that focus on the FPA or diplomatic in the context of developing countries. Adopting a wide variety of approaches, classical theories of IR have criticized the lack of focus on the Global South theme and made a case for controlling existing methods.

This contribution aims to address inadequacies in many ways. Apparently, they deal with various foreign policy issues, from security policies to economic and environmental policies. Apart from their decision making, it includes various bilateral relations and institutional settings such as the United Nations Security Council, the World Trade Organization, the International Monetary Fund, the South Asian Association for Regional Cooperation in various ways. In all these cases the examples of selection were based on methodological criteria and individual research strategy.

Study foreign policy

Before we assess the status of social scientific theories within the study of Indian foreign policy, some clarifications about our understanding of theory and theory are in order. This article adopts a broad understanding of the theory as it seeks to understand primarily that theoretical and methodological tools are sufficient for Indian foreign policy. Therefore, it presents a wide range of variables and methods. Assume a minimum degree of regularity and predictability of this social behavior. It essentially equals systematic and intersubjectively understandable generalization. However, it is not limited to beliefs about general and influence or constitutional relations. It also includes clustering using empirical event descriptions and concepts. As James Rosenow once said, R must be predisposed to ask theoretically about every event, every situation, or every event, for example, we can ask if the US-Indian relationship is the so-called peace '. An example of 'democratic peace'?

This article contrasts the widely informed view of Indian schools' efforts to explore ideas or Indian grand strategies, but where Indian foreign policy principles do not figure prominently. Most of the articles in this field engage in a non-systematic and theoretical way rather than a theoretical model. Even those who provide profound differences in the political and social classes that shape Indian foreign policy do not systematically follow the FPA and IR doctrine.

There are some notable exceptions that are limited to the analysis of India's bilateral relations or to one area of ​​Indian foreign policy. In addition, many works on Indian foreign policies provide analysis rather than policy-oriented theoretical ones. This trend comes partly from the educational and social setting in which Indian FPA and IR scholarship develop. Theory-oriented works can be seen as deviations from practical problems and even from the need to gain academic prestige, new Indian works on Western IR theory such as Deepshikha Shahi and Gennaro Escoyan have emerged over the years.

Theory-based work rules nevertheless remain the exception. Another reason for that might be a more or less tacit assumption of a highly volatile and therefore unpredictable policy-making process that generally escapes theory attempts. The formulation of Indian foreign policy is often characterized by individual leaders, pragmatism, inconsistency, lack of strategic vision and ad hocism. But the non-existence, irrelevance, or absence of grand debate of strategic planning also needs to be clarified. This, in turn, can be derived from theoretical models that highlight structural conditions.

Among those attempting this theoretical field is an edited volume by Sumit Ganguly in which several contributors use well-known levels of the analysis framework. But mainly refers to the policies of India and mainly describes the development of individual countries like Russia and America. A shared recording, the field of international relations in India and the nation Kanti Bajpai and Siddharth Mallavarpura touch only marginally on the principles of FPA and IR as it attempts to engage in more comprehensive decisions and debates and debates in political science. Some other works appear wedded to single analytical approaches or applying a single theoretical perspective without comparing it with other paradigms Finally, Valerie Hudson and Claus Brummer 'Foreign policy analysis by Ganguly and Pardesi in North America is included in the foreign policy analysis in India', yet overall differs from that edited central concept, as it attempts to summarize. Have FPA and related research in non-Western academic communities.

In other respects, what account is different from Indian foreign policy? There must be at least three dimensions to consider. For the first time, policy-making challenges related to Indian foreign politics and ideological issues were established. Some categories may need to be recalculated and redefined. Take, for example, the conditions for stable majority rule according to standard political science approaches and the different ways in which a majority is achieved in Indian politics.

A historical approach is an important way to reclaim an empirical reality that helps to rethink analytical tools. A second dimension takes into account the problems of methodology and data availability. For example, the Indian public opinion is still hampered by the lack of opinion polls, in that case, conditions have improved with the proliferation of news channels and online media since the 1990s. Third, and finally, the explanatory power of the standard IR and FPA approaches may differ significantly between Indian foreign policy and other cases from Western Europe and North America. For example, from a liberal view of foreign policy decisions in India, trade policies do not explain well with the exception of private actors because private actors have few opportunities to gain access to decision-making processes.

Perspective for future research

New ways to develop a conceptually strong and innovative analysis of Indian foreign policy are not without pitfalls for several reasons. First, the empirical grounding that this involves requires access to sources sometimes hard to secure. In particular, researchers in India still face comparatively high barriers to using archival material, while another source of information, the media, still exhibits deficiencies in foreign policy.

Secondly, to some extent, the work requires a multi-disciplinary background, particularly a double familiarity with India and with IR theory. Acquiring this background, it is sometimes difficult to reconcile with the requirements for a career in many university systems. For instance, we might ask whether and how the opening up of India’s economy affected the lobbying of industrial associations with respect to the foreign policy agenda. Second, it is important not to overlook pre-colonial times as well as India’s external affairs during the British Raj. The informal Indian delegation to the San Francisco Conference, and focused on the ideal by Bernhard Beetlemeier-Berini's article, pointed to the development of the theoretical, finding ways to ideologically influence the impact of classical Indian literature in strategic cultures.

Third, Indian foreign policy can indeed be guided by ambitious strategic understanding and change, with some irreversible, foreign policy norms also often assumed that it should result in the sub-foreign policy. New research can be used to support and refute. This policy asserts that Indian foreign policymakers followed a clear strategy as pointed out by Tobias Daniel and Herbert Wolf, an ambitious foreign policy orientation is not without advantages.

Saturday, 4 April 2020

How to mushroom cultivation


Biological manipulation the Culture of mushrooms is a remarkable system that reduces the likelihood of harmful organisms and is beneficial. When it grows well, it becomes a living ecosystem suitable for mushroom growth.  Sometimes the mycelium used in composting mushrooms affects the system to a large extent and the competition for growth of other microorganisms can be minimized. Although mushroom manure is not a selective medium, other fungi can grow well before composting and hatching mushrooms, often at the expense of mushroom mycelium. It is derived entirely from white mushrooms, different production processes using and growing different mushrooms, different overall environments in which the mushroom grows.

Culture

Compost: the ingredients

Straw, wheat straw is commonly used for mushroom manure, or as a major raw material for a mushroom substrate, although other crops, such as barley, rice, and oilseeds, etc. The grass is a major component of mushroom manure in the United States. Mushroom growers have used mixed sandy straw, called compost with wheat stove, poultry manure. Complex mixtures include crushed corn shells, sour foods, and fertilizers such as urea or ammonium nitrate that provide additional carbohydrates and nitrogen.

Composting

The process of converting these fertilizers into a suitable medium for mushroom production by fermentation takes place at various stages. Initially, the material is mixed and moistened (stage 0), composting begins (stage I), pasteurized and composting completed (stage II), and finally, colonized by mushroom mycelium (stage III).

phase 0

The purpose of this phase is to fertilize, mix and wet the raw materials, during which various microorganisms break down the straw. During this process, the raw material is made by wetting well in large piles that are often transferred. This initial mixing and wetting phase occur over a period of 7 days.

Phase I

After the wetting and mixing stage, the compost is made in a long, narrow pile or windrow, in which the composting process continues. Traditionally the windows of phase I compost are made up in the open or under the protection of an open-sided shed. The phase is I process takes as a further 7 days. A compost pile usually reaches a temperature (70–75) C), which is sufficient to kill pests and pathogens in the compost or straw. Mechanical manure is replaced several times by the turner, the outer layer may not reach the middle in a few days and cannot achieve high temperatures as a result. The use of specially constructed bunkers with underfloor ventilation and sometimes with partially open top or roof underside has become widespread. The manure is put into these bunkers after a short period of time. The constant supply of air from the bottom and the removal of manure from the bunkers from the insulation provided by the walls results in 2- or 3-day intervals at temperatures of 80 or C or more, Stage I bunker manure production. Produced over two or three days compared to those produced by traditional methods.

Prewet/phase I composting methods are still being actively developed to further improve productivity and reduce odor pollution. In the initial stages of compost production, large amounts of water are used and water is collected in large containers. Water contains organic materials that ferment, especially in warm climates. It then becomes anaerobic, which causes the stink. This water, often called Y good water, must be aerated well and can then be recycled and used to make more manure. It can contain large quantities of soluble salts which may inhibit composting or mushroom mycelial growth if their concentration becomes too high.

Phase II

The process of composting is continued at this stage until it is considered suitable for the development of mushroom mycelium. More activity in one process less will be required in another, too much activity in the first phase may lead to insufficient activity in the second. The phase II process is normal to last approximately 6 days.

There is greater traditionally, control of the environment in phase II than in phase I. At the beginning of phase II, the compost temperature is allowed to settle (often referred to as leveling) so that it is more or less uniform throughout. The temperature is raised for the fermentation process to produce heat or by the introduction of steam, either when the temperature of the compost is below or below 60 ° C, the rise in temperature is prevented by the arrival of air. is. The temperature at 60 hours C is around 8-10 hours. The temperature of the conditioning process compost is reduced to 48 for C.  At 48˚C, the thermo-tolerant fungi remaining, and in particular, the fungus Scytalidium sp., grow quickly and colonize the compost. The biomass of these thermo-tolerant organisms accumulating during the conditioning process increases the suitability of the compost for mushroom growth.

At the end of conditioning, about 4 days of compost is cooled to 25 C so that it can be removed and brightened. It should be stable free of ammonia. Cooling requires large amounts of air. As long as this air is filtered to remove spores or pathogens, there is danger. can negate all careful preparation in the production process.

Compost smells

This nature and process can cause a very unpleasant odor, especially at certain stages. The older systems of prewet and phase I, with no underfloor ventilation, often resulted in anaerobic conditions, especially in the centers of the piles of compost. Increasing the pressure to reduce the odor of under-compost ventilation has also led to a large increase in the use of bunkers, which leads to a decrease in odor. Unless biofuels are used, odor pollution is not prevented by the bunker system.

Compost analysis

There is no chemical to compost mushrooms, excellent crops can be produced within a range of analysis. Manufacturers regularly analyze manure to monitor their own systems and to detect unplanned variability in the early stages. Both Phases I and Phase II manures are analyzed, for Phase I manure, pH, water and nitrogen content are obtained. Generally higher than pH 8, water around 75%, and 1.5–2.0% of fresh weight nitrogen. Phase II figures are pH 7.2, water content 68–72%, and nitrogen 2.5–2.7%. The carbon to nitrogen ratio in spawning is about 15: 1 to 18: 1. When this ratio exceeds 20: 1, the likelihood of weeds developing increases.

Mushroom compost

A selective medium is one that will grow a particular organism and no other. Mushroom manure is not selective, but it is a process of compost production for the growth of mycelium, especially the second stage process, filled with a moderate but thermo-tolerant organism that is sub-party temperature. They are in the dormant state due to spawning. This partial organic vacuum is filled with the introduction of large amounts of mushroom spawn. Phase II has not done extensive work on the range of other organisms Mushrooms will grow well in compost, but a number are known to result in accidental contamination or before spawning.  Recent work has shown that some of these molds, while not inducing symptoms of the disease on mushrooms, can have a commercially significant effect on their yields. After being colonized by a mushroom mycelium, manure is not vulnerable to being infected by other organisms.

Spawning, spawn-running, and phase III compost Spawning 

Once the compost has completed the phase II process and has been cooled to 25˚C, it is ready for spawning. At this stage, it is particularly important to be certain that the ammonia level in the air in the compost is below 5 ppm. Spawn, mushroom mycelium growing on sterilized grains, or less commonly on a grain-free medium, is thoroughly mixed into the compost by various mechanical means according to the growing system employed (6). A rate of the spawn of 7–8 liters per tonne (or 0.5% by weight) of phase II compost is normal.

Spawn-running

According to the system used in the field, spawning grain is a colony of manure from the inoculum, which is usually 13–18 days old. The temperature is 25, the high relative humidity for environmental spawn-runs, mainly to prevent composting. A concentration of 2% or more of carbon dioxide is beneficial because it is toxic to humans with large amounts of carbon dioxide. This is achieved by reassembling the air within the spawn-running room in the atmosphere, cooling the air if necessary. Spawn-running, like second-stage manure, can occur in final mounting containers or in bulk.


Phase III compost

This compost is prepared in large tunnels, which may be similar to those used for Phase II, or Phase III, which during spawn-run the temperature is controlled using filtered cold air, Which is fed through manure. In this way, a temperature of 25˚C can be maintained, and the compost is completely colonized in 16–18 days. It is then removed from the tunnel and transported in bulk to shelves or machinery where it can be placed in trays, bags or blocks.  It is very important to control oxygen levels during the spawn-running process, oxygen levels should not be less than 16% during Phase III. Hygiene, along with stage III production, can initiate pathogens, weed molds, mycelial fragments as mushrooms, and mushroom spore diseases. Phase III has its own compost production facility to eliminate the need for the farm.

Supplementation

Some systems of growing to allow this to be done with advantage, just before casing. The mechanism of this mushroom nutritional enhancement has not been fully understood, with beneficial effects on yield levels often considered to be the least cost-effective and can be up to 20%. A high protein product, which is treated with heat or formaldehyde to give a slow-release preparation, is added to the compost and spawned at the same time. This technique is not used where it is difficult to control high compost temperatures as a problem or where adequate mixing is difficult where the compost is of questionable quality.

Casing

To promote mushroom production, it is necessary to add a relatively inert surface layer of the nutrient to the relatively organic mushroom in the compost. Types of peat and chalk vary with the country, although now in many countries a mixture of well humified black peat and a by-product of the sugar beet industry called sugar beet lime is used. This mixture remains open which is effectively released into the crop, leading to greater water consumption and is used for crop control.

The casing layer is applied 4–5 cm deep. Must be an alkaline or neutral pH. In addition to stimulating fruiting, this water-holding stock material required for mushrooms and for high yields is easily contaminated. There can be severe outbreaks of pests and diseases. Treatment can be done to remove pests and pathogens. They should not be sterilized but must be heated to temperatures that are sufficient to kill harmful bacteria that are important for maintaining bacteria. Steam–air mixtures have been used for this purpose and when in equal proportions the mixture has a  maximum temperature of 80˚C. Ideally, a temperature of 60˚C should be used, and the casing heated for 30 minutes.

Spawned casing

There are two ways to use a mushroom inoculum It is the mushroom mycelium that grows on very small pieces of low nutrient medium such as mica or peat. Ordinary spawn is unsuitable for this use. It is mixed with the inoculum when it expands so it is evenly distributed on the surface and then rotavated or in rake.

A spawn-run compost that is added to the casing in the same way as for the inoculum is known as the casing. The parity and speed of the subdivision increase greatly with the use of the casing. The advantages of this technique are considerable in terms of time and duration of the crop but are serious for pathogenic and pest development, spawn-run manure is used. The success of this method depends entirely on the selection of manure, which is free from pests, pathogens, and molds.

Ruffling

This is an alternative to the use of casing spawn or caching. The casing is either deeply rotovated immediately after application and some of the colonized compost from the top layers of the compost is mixed into it, or renovation is Is done when mycelium does not develop from manure in the lower layer of the cover, it adds the mycelium of the cover. These techniques may have the effect of using a casing inoculum, they are less reliable because they are more difficult to regulate. Stopping the wrapper several days after mycelial growth may improve the first flush and help regulate its timing. This can be a very effective way of spreading the disease.


Allergies

In particular, germs, actinomycetes, are produced in large numbers during composting. What makes Firefang, 'the white increase in manure that appears at the end of Phase II, is their spectacular growth. During the preparation of compost, at any stage, many organisms are formed. Workers constantly exposed to these organisms may develop mushroom grower's lung. It is important therefore that those working with phase II and phase III compost wear an aspirated helmet.

Cropping

When the mycelium crop is induced to bear fruit. This is also done by reducing the air temperature for several days (3 to 5) while reducing the concentration of carbon dioxide in the air. Because mushrooms grow quickly. Fruiting occurs well into the break, approximately 17 days after the first cover, and continues at approximately weekly intervals. These three flushes are picked up, and then the crop is removed to make room for the next crop. The trend of taking only two flushes is increasing.

About 8-13 crops are harvested every year from home. The first two flushes are most commonly produced in mushrooms and are nearly identical in size. About half of the first two mushrooms are produced in the third flush. If flushed later, they produce less, and for this reason, are considered non-economic. Only two flushes can be taken in biological crops to prevent epidemics and to keep pests and pathogens permanently low.

From that time the wrapper is immersed in water at regular intervals, just before the mushroom is introduced during harvest. Watering is started again after the first flush is over, and most of the water between the second and third flushes is applied before the first flush, and at this stage, 25 liters per liter can be used.

Pickers go in and out of homes to harvest crops. Any insect or pathogen that crops up. Pest and pathogenesis are spread within and between crops, if pests are to be controlled within a reasonable range, and effective methods of crop termination, compost emptying and disposal are required, then pest and disease identification is important.


Pests and pathogens

There are some stages in mushroom production that are more vulnerable to the penetration of pests and pathogens. One of the stages in crop production indicates significant timing in relation to pest and pathogen risk.