eChapters

The understanding of VAM symbiont and VAM symbiosis is of prime importance in manipulating VAM associations for the welfare of plants. Many contributions have been made worldover in the areas of taxonomy, morphology, anatomy, histology, cytology and genetics of VAM fungi and/or their associations with the plants. However, the share of Indian mycorrhizasts in such contributions is negligible. The following description gives an account of work done by the mycorrhizasts of the country in these areas.

NEW CELLS ARE PRODUCED BY DIVISION OF PREVIOUSLY EXISTING CELLS

All cells come from previously existing cells

To make a new cell identical to itself a cell must perform 4 tasks:

It must grow and make additional copies of all its organelles, enzymes, etc..

It must duplicate its DNA

It must accurately separate the DNA into 2 units, so that each cell gets a full set

It must divide into 2 cells (cytokinesis)

Fermentation

The term fermentation is loosely used to denote any process in which microorganisms are involved, regards of whether or not the organism is growing in the presence of molecular oxygen. Thus, it can be defined as 'an ATP generating metabolic process in which organic compounds serve both as electron donor (becoming oxidized) and electron acceptor(becoming reduced). Energetically, fermentations are poor energy yielding process and products have lower energy content then the substrates. Since there is no net oxidation in fermentation, the number of molecules of C, H and O remain the same in products as in the substrate.

Abiotic Stress Tolerance: The ability of plants to withstand and adapt to nonliving environmental stressors, such as drought, salinity, or extreme temperatures. Afforestation and Reforestation: Afforestation involves planting new forests in previously non-forested areas, while reforestation involves restoring degraded or deforested lands with trees to sequester carbon. Agrarian Society: A society characterized by agriculture as the primary means of subsistence and economic activity. Agrarian: Pertaining to the cultivation of land, agriculture, or rural life. Agribusiness: The commercial activities, including production, processing, and distribution, related to agriculture and farming. Agricultural Chemistry: A branch of chemistry that focuses on chemical processes and substances related to agriculture, including soil chemistry, fertilizer composition, and pesticide development. Agricultural Diversification: The strategy of expanding the range of crops, livestock, or other agricultural activities in a rural area to increase income and food security. Agricultural Economics: A branch of economics that focuses on the production, distribution, and consumption of agricultural goods and services, as well as the economic factors and policies that influence agricultural markets. Agricultural Extension: The application of scientific research and new technologies to agricultural practices through education and advisory services. Agricultural Innovation: The process of developing and adopting new ideas, practices, and technologies in agriculture. Agricultural Machinery: Various mechanical devices and equipment designed for use in farming, such as tractors, plows, and harvesters. Agricultural Subsidies: Financial incentives provided by governments to farmers or agricultural producers to support their production, stabilize prices, or achieve other economic or social objectives. Agriculture: The science and practice of cultivating crops, raising livestock, and managing resources for food production and other agricultural products. Agroecology: The scientific discipline that applies ecological principles to the design and management of sustainable agricultural systems, focusing on biodiversity, nutrient cycling, and reduced environmental impact.

Allele-Specific PCR

This diagnostic or cloning technique is used to identify or utilize single- nucleotide polymorphisms (SNPs) (single base differences in DNA). It requires prior knowledge of a DNA sequence, including differences between alleles, and uses primers whose 3' ends encompass the SNP. PCR amplification under stringent conditions is much less efficient in the presence of a mismatch between template and primer, so successful amplification with an SNP-specific primer signals presence of the specific SNP in a sequence.

Amplification Refractive Mutation System (ARMS) - PCR

In ARMS, the primer pair is designed so that one of the 3' ends coincides with a variant nucleotide in the target sequence. When the primer mismatches the template the frequency of extension is very low and consequently the effective number of sequence copies available for amplification is greatly reduced. ARMS PCR exploits a thermostable polymerase that lacks 3' exonuclease activity (usually Taq polymerase). Such enzymes extend primers bound to their target sequences very inefficiently when the 3' base is mismatched. Because the 3' exonuclease activity required for mismatch repair is not present, the extension of such primers in PCR is a rare event and amplification is retarded. However, once mismatch extension has occurred amplification proceeds normally from the newly synthesised target strand. Thus an important principle of ARMS is that non-matching (i.e. non-matching at only the 3' end of one primer) template may be amplified. The factors that contribute to this apparent ‘failure’ of ARMS are that when very high numbers of template molecules are added to the reaction, amplification is likely to proceed because the small proportion of mismatched primer extensions reach the sensitivity threshold of the reaction. Second, certain mismatches are extended more efficiently than others so that proportion extended in each PCR cycle varies.

The diversity of the haloarchaea found within a crystallizer pond of a solar saltern located in Siridao and Ribandar, Goa, India was examined. Both cultured-based and culture independent methodology were employed which included  surface spreading of samples on different media containing 25% crude salt/NaCl, DNA extraction from sediment and water samples, amplification of 16S rRNA gene and DGGE.

ABSTRACT

Frankia is a gram-positive, microaerophilic, actinomycete that enters into symbiotic associations with a number of woody dicotyledonous plants called actinorhizal plants. Frankia can fix atmospheric nitrogen through such associations. The actinorhizal-Frankia association is beneficial for the environment, since it increases the fertility of soils. Extensive studies on the biochemical and molecular aspects helped in the classification of Frankia. PCR-RFLP studies of the 16S rRNA and the nif regions of Frankia revealed considerable information regarding the diversity of Frankia strains, isolated from different parts of the world. The completion of three whole genomes of Frankia has bolstered the study of the molecular organization of the genome. Comparative genomics study of the three complete genomes revealed that, the strains reflected the biogeographical history of the host plants they infected. Striking similarity in the codon usage patterns highlights the fact that they may have evolved as a unit. In the present review we highlighted the taxonomy of Frankia and the host plants, the Frankia-actinorhizal association, regulation of infectivity, biochemical and molecular characterization, phylogeny and genomics of Frankia and stressed the need for metabolomic study of the Frankia-actinorhizal association.

Two types of molecular weight (MW) standards are routinely used. The Lambda/HindIII and PhiX174/HaeIII MW standards provide a useful reference for calculating molecular weights of large and small DNA fragments, respectively, after electrophoretic separation; the “internal MW standards” provide a means for normalizing fragment migration distances within each lane to facilitate comparisons between lanes on the same or different luminographs in fingerprinting studies.

Monitoring and evaluation constitute systematic processes of tracking, assessing, and learning from program implementation and outcomes to improve performance, demonstrate accountability, and inform decision-making. These complementary yet distinct functions serve as essential management tools that enable organizations and programs to understand whether they are achieving their intended objectives, efficiently using resources, and creating desired changes in target populations or systems. The integration of monitoring and evaluation creates powerful feedback loops that enhance program effectiveness while providing evidence for policy development, resource allocation, and strategic planning. Monitoring is defined as the systematic and continuous collection, analysis, and use of information about program implementation, progress toward objectives, and changes in context that may affect program performance. It represents an ongoing process that tracks inputs, activities,

A. Morphological Examination of Bacterial Samples
Introduction
Bacteria are most widely distributed, the simplest in morphology, the smallest in size and difficult to identify. They are prokaryotic and a few are photosynthetic. Most bacteria are only 0.5 to 2.0 μm in diameter. Bacteria are generally rod, spherical or curved shaped. Rod shaped bacteria may vary considerably in length, have square round or pointed ends and may be motile or non-motile. The spherical or coccus shaped bacteria may occur single, in pairs in tetrads, in chains or in regular masses. The helical and curved shaped bacteria exist as slender spirochetes, spirillum and bent rods (vibrios). In this exercise the ubiquitousness of these organisms will be demonstrated in the air and water, on body and in mouth etc.
Materials
1. Petri plates containing nutrient agar
2. Sterile cotton swabs
3. Sterile water blank
4. Tube of nutrient broth
5. Materials for simple staining

Introduction

The motile bacteria show movements with the help of flagella. The motility of bacteria can be observed by hanging drop method under microscope.

Requirements

1. Bacterial culture
2. Cavity slide
3. Vaseline
4. Coverslip

Procedure

1. Place a very small drop of 24 hours old bacterial culture in the center of a coverslip.
2. Put a small amount of Vaseline at each cover of the depression side of the cavity.
3. Invert the cavity slide over the coverslip. The coverslip adheres to glass slide. When the coverslip is inverted, the hanging drop is suspended in the well.

Motivation represents the psychological force that drives individuals toward specific goals and behaviors, serving as the catalyst between intention and action. At its core, motivation encompasses the internal processes that energize, direct, and sustain human behavior over time. The term derives from the Latin word “movere,” meaning to move, which aptly captures its fundamental purpose of propelling individuals from a state of rest to purposeful activity. Contemporary organizational psychology defines motivation as the willingness to exert high levels of effort toward organizational goals, conditioned by the effort’s ability to satisfy individual needs. The essential elements of motivation form an interconnected system that transforms latent potential into observable behavior. The first element involves needs, which represent deficiencies or imbalances that create tension within an individual. These needs can be physiological,

In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryotic cells These organelles range from 0.5–10 micrometers (µm) in diameter. Mitochondria are sometimes described as “cellular power plants” because they generate most of the cell’s supply energy in form of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth. Mitochondria have been implicated in several human diseases, including mitochondrial disorders and cardiac dysfunction, and may play a role in the aging process.

Several characteristics make mitochondria unique. The number of mitochondria in a cell varies widely by organism and tissue type. Many cells have only a single mitochondrion, whereas others can contain several thousand mitochondria. The organelle is composed of compartments that carry out specialized functions. These compartments or regions include the outer membrane, the intermembrane space, the inner membrane, and the cristae and matrix. Mitochondrial proteins vary depending on the tissue and the species. In humans, 615 distinct types of proteins have been identified from cardiac mitochondria; whereas in Murinae (rats), 940 proteins encoded by distinct genes have been reported. The number of proteins encoded in plant mitochondrial DNA is probably not much higher than the number encoded in mammalian mitochondria.Experiments have shown that most of the protein synthesis in isolated maize mitochondria can be accounted for by some 18-20 polypeptidesThe mitochondrial proteome is thought to be dynamically regulated. Although most of a cell’s DNA is contained in the cell nucleus, the mitochondrion has its own independent genome. Further, its DNA shows substantial similarity to bacterial genomes.

Abstract

In recent years, significant studies have been carried out on Plant growth promoting rizhobacteria (PGPR) to replace the usage of pesticides and fertilizers to improve the plant health. Plant growth promoting rizhobacteria (PGPR) is a group of rhizosphere bacteria, which are symbionts to plants and influence their growth by providing plant growth promoting substances. Different bacterial genera act as plant growth promoting rizhobacteria (PGPR): Pseudomonas sp., Rhizobium sp., Azotobacter sp., Bacillus sp. Pseudomonads are gram negative rods, aerobic, fluorescent, motile and are able to produce siderophores which influence plant growth. There are multiple potential traits offered to the plants by plant growth promoting (PGP) Pseudomonas sp. are (1) Biocontrol agent against plant pathogens (2) Induced systemic resistance, which is a defense mechanisms in plants preceding to pathogenic attack (3) Influence of plant growth promoting (PGP) Pseudomonas sp.on agricultural crops (4) Siderophores, which are low molecular, high affinity iron chelating compounds which benefits the plants to acquire iron molecules (5) Nitrogen fixation (6) Phytoremediation of heavy metals (7) Solubilization of inorganic phosphates (8) Secretion of plant hormones (9) Bacteriocins(10) Antifungal factors (11) Antibiosis traits and (12) Endophytic PGP Pseudomonas sp.

To isolate a streptomycin resistant mutant of E.coli by Direct selection using Gradient Plate Method.

Introduction

Zylbalskii devised this technique.

A mutation is any change in the nucleotide sequence of DNA. These changes are heritable. Although most mutations are harmful to the organism, a small percentage is beneficial under certain environmental conditions. Mutation can occur during chromosome duplication and they may be spontaneous of they may be induced by mutagenic agent. In this experiment, we select for a mutation causing streptomycin resistance in E. coli. Resistant mutants will be detected directly using thy gradient plate method.

Principle

Microbiologist developed a highly efficient method for isolation of antibiotic resistant mutant. The gradient is said as gradient of antibiotic formed on an agar plate. A gene imparting resistant toward an antibiotic is present in plasmid or chromosome. The occurrence of mutant with different level of streptomycin resistant involves mutation of gene with unequal potential. This means that under certain cells degree of mutation is more while few shows less mutation. Some cells show intermediate resistant while others show completes resistant. The resistant in cell against streptomycin of this type, while in case of penicillin resistant increases step arise & so resistant mutant of high concentration of penicillin cannot be isolated/ obtained. While it is possible with streptomycin obtaining high resistance to penicillin stepwise & so this stepwise increase in resistance involves mutation of gene with equal potential. This theory of mutation through multi step procedure. The gene direct the organism to produce an enzyme, which inactivates an antibiotic & thus resistance to antibiotic, is observed in case of cells. Resistance of antibiotic is a plasmid-mediated resistance.

To isolate a streptomycin resistant mutant of E.coli by Indirect selection using Replica Plate Method.

Introduction

J. Lederberg & his wife E. M. Lederberg devised this technique in 1952.

U.V. light coming from the sun emits strong radiation to extent the antibacterial effect in the microbial population. However it has a very short penetration power, UV light is used as a mutagenic agent & was used by Beedle & Tatum to obtain biochemical mutation. The mutation rate is only once in 10^-9 cells per population. Then hence using mutagens like UV light by 10 to 1000 folds will increase this mutation rate.

In isolation of the mutant using UV light the dose of UV light is measured by its units/nm² organisms. The time selected for the mutation is calculated on the basis of 0.1 to 1% survival & a suitable biochemical character is used to evaluate the mutation.