eChapters

Introduction

Phosphate solubilising microorganisms include different groups of microorganisms such as bacteria, fungi and actinomycetes, which convert insoluble phosphatic compounds into soluble form. The species of Pseudomonas, Micrococcus, Bacillus, Flavobacterium, Penicillium, Fusarium, Sclerotium, Aspergillus and others have been reported to be active in bioconversion. Such bacteria and fungi can grow in media where Ca₃(PO₄) ₂, FePO₄, AlPO₄, apatite, bone meal, rock phosphate or similar insoluble phosphate compounds are the sole source of phosphate. Such microorganisms not only assimilate phosphorus but they also cause a large portion of soluble phosphate to be released in quantities in excess of their own requirements. The solubilisation is not restricted to calcium salts but iron

Introduction

Biological nitrification is a two-phase process, which consists of the oxidation of ammonia-nitrogen to nitrite-nitrogen by species of genera Nitrosomonas, Nitrosospira and Nitrosogloea, and the subsequent oxidation of nitrite-nitrogen to nitrate-nitrogen by species of the genera Nitrobacter and Nitrocystis. The following equations explain the reaction.The importance of nitrifying organisms in soil is based on their capacity to produce nitrate, the major source of nitrogen assimilated by higher plants. The rate of nitrification is dependent on such factors as concentration of NH₄+, temperature, moisture, aeration and pH. Bacteria have their optimal activity at an alkaline reaction. Below pH 7.0 the process declines.

Introduction

As Rhizobia are slow growers so their enumeration by plating techniques is less recommended. Rhizobia can be enumerated in the presence of a large number of other organisms by most probable number (MPN) method. Soil containing Rhizobia is diluted in liquid and dilutions are used to inoculate roots of legumes. The presence of Rhizobia in a given experimental unit, inoculated by a given dilution, is indicated by the formation of at least one nodule on a root. Thus, the method involves the growth of legumes under conditions such that a single rhizobia cell can multiply and forms at least one nodule on the root.

Most Probable Number Method: This method permits estimation

Introduction

Rhizobia are Gram-negative soil bacteria , aerobic nitrogen fixers and adhere to the roots of leguminous plants. Fixed nitrogen is assimilated to proteins and is transported along the plants. A part of proteins is also released in rhizosphere region.

Requirements

1. Yeast Extract Mannitol Agar (YEMA)
2. Sterile saline
3. HgCl₂ solution (1%)
4. Ethanol (70%)
5. Root nodules of Mung bean
6. Water blanks
7. Pipettes
8. Petri plates
9. BOD Incubator

Introduction

Photosynthetic bacteria are autotrophs and anaerobes. These bacteria produce Hydrogen sulphide. These are predominant in the bottom of stagnant water enriched with mud.

Requirements

1. Mud sample
2. Enrichment medium of Photosynthetic bacteria or salt solution (1.0g/lt. of (NH⁴)₂SO⁴ 1 g; K²HPO⁴, 1 g; MgSO⁴,0.2g; NaCl, 5g; pH 7.2)
3. Sterilized bottle with plug
4. Fluorescent tube

Introduction

A microscope is an optical instrument consisting of a lens or a combination of lenses for making magnified images of minute objects. A simple microscope consists of a single lens of magnified glass held in a frame, usually adjustable and has a stand for holding the object and a mirror for reflecting the light. But a compound microscope consists of two lenses i.e., objective and eye piece respectively. A compound microscope gives much greater magnification than simple microscope. The compound microscope will be extensively used in this course in studying various morphological and staining characters of soil microorganisms.

Introduction

A haemocytometer is a single piece of glass with an H-shaped trough forming two counting areas. Hemocytometers are used to determine the total cell count and viability of many different cell types The full grid on a hemocytometer contains nine squares, each of which is 1 mm¹. Each counting area is defined by a grid system. It has supports that hold the cover glass at the proper distance (0.1 mm) above these areas for the calculation of the concentration per volume of liquid.

Requirements

1. Inoculum
2. Inoculation needle
3. Test tubes

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.

Introduction

Bacteria are very minute and colourless in their natural environment and are difficult to be seen under compound microscope. To view their exact morphology, various kinds of stains are used. Stains are of three main types.

Acidic stains: These are those stains in which charge on dye ion is negative. e.g. India Ink, Eosin etc.

Basic stains: These are those stains in which charge on dye ion is positive. e.g. Methylene blue, Crystal violet etc,

Neutral stains: These are the salts of dye acid in dye base. e.g. Eosinate of Methylene blue.

Introduction

The actinomycetes are gram positive, non-motile, non-sporulating and nonacid fast bacteria. Sometimes these are called ray fungi and are connecting link between the bacteria and the true fungi. They possess a very fine vegetative mycelium that does not fragment into bacillary or coccoid forms and therefore their colonies on agar are commonly cohesive or tough in consistency. In many soils, the actinomycetes accounts from 10 to 25% of the total count on agar plates. Their number is higher in soils of low moisture content than in wet soils. They are responsible for degrading more resistant carbon material in soil like humus. They are also important flora of manure heaps. Most of these, particularly Streptomyces, produce antibiotics and so are of a great value

Introduction

Fungi constitute an important part of microflora of normal soil. In soils, fungal propagules vary from 2 x 10⁴ to 1 x 10⁶ per gram soil. The propagule being considered as fungal hyphae, spore, and hyphal fragments which is capable of giving colony on the plate. Most soil forms have a filamentous organisation capable of reproduction by means of spores. Their development is especially favoured by soils having acidic reactions. Soil fungi has significant role in organic matter decomposition, as a plant pathogens and in the interaction with other soil microorganisms. Agar plate count method is commonly used as a measure of fungal population in soil.

Introduction

Soil is the natural habitat of a number of microbes viz. bacteria, fungi, actinomycetes, algae and many viruses. Out of these, bacteria are morphologically very simple as made up of just one cell of small size, therefore can multiply rapidly. Each viable bacterium at appropriate dilution can develop into a colony. Hence by counting the number of these colonies which develop on a selective growth medium, the number of viable cells of bacteria present in soil can be ascertained. Since the number of the bacteria present in soil is very high, the soil suspension is to be sufficiently diluted to reduce the number of colonies and to prevent their overlapping. The number of colonies formed from a diluted sample multiplied by the extent of dilution (dilution factor) gives the number of viable cells present

Introduction

Microbes like all other living beings require suitable nutrients as well as favourable environment like pH, osmotic pressure, temperature, humidity etc. for growth. The substrate/food base which fulfills any of these requirements and supports the growth of an organism is called culture medium. Selection of a medium to grow a particular type of microorganism is extremely important, as the microbes vary in their nutritional requirements. Thus, different media are used for different groups of microbes. The following are the main types of media:

a) Natural/Empirical media: These are made up of natural substrates, such as herbaceous or woody stems, seeds, leaves, corn meal, wheat germ, and oatmeal etc.The exact chemical composition of this media is not known. e.g. Nutrient agar

b) Semi-synthetic media: 

1. General Instructions

Instructions to work in the laboratory are given below. Students are advised to read them carefully before they begin their work in the laboratory.

• Apparatus to be used should be neat and clean.
• Graduated pipette should be used for pipetting.
• The small amount of liquid remaining in the pipette should not be blown out while standardizing the pipettes; allowance is always made for this. However, a frosted ring near the top of recently manufactured pipettes indicates that the last drop is to be blown out.

Q.1 Fill in the blanks

1. _______and_______are pulse crops.
2. Rice is a_______pollinated crop.
3. Different breeds of cattle are_______and_______
4. _______and_______are sugar crops.
5. _______Important cereals are_______and_______
6. _______and_______are examples of fibre crops.
7. _______Dapog method is originated from_______
8. The origin of rice is_______region.
9. Best temperature range for germination of wheat is_______oC.
10. Adsali sugarcane is of_______months duration.
11. _______portion is taken in cane for propagation

Farming System Approach (FSA)

Farming systems refers deliberate raising of crops,forest and fruit trees, animals including fisheries, piggery and duck farming, sericulture, mushroom, on a given unit of land to increase the productivity and profitability, to upgrade natural resource base and to achieve overall improvement in the environment

The philosophy behind shifting from cropping system to the farming system mode involves

1. In situ recycling of organic residues including farm wastes generated at the farm to reduce the dependency on chemicals
2. Decrease in cost of cultivation through enhance input use efficiency,
3. Effective use of bye-products/wastes of one component for the benefit of other component/components
4. Upgrading of soil and water quality and bio-diversity,

The women is the backbone of agricultural workforce and are a vital part of Indian economy. Over the years, there is a gradual realization of the key role of women in agricultural development and their contribution in the field of agriculture, food security, horticulture, dairy, nutrition, sericulture, fisheries, and other allied sectors. Women form the backbone of agriculture, in India, Comprising the majority of agricultural laborers, women have been putting labour not only in terms of physical output but also in terms of quality and efficiency. With various targeted efforts, her enlightenment will change the face of rural India.

Women make essential contributions to the agricultural and rural economies in all developing countries. Their roles vary considerably between and within regions and are changing rapidly in many parts of the world

Power transmission through belts, pullies, gears, speed and size

Both stationary and portable types of agricultural machines make use of various types of power transmitting devices for doing useful work.

Some of these power transmitting devices are meant to convert rotary motion into linear motion or oscillating motion.

This transmission of power from generating unit to useful unit is possible through belts, pullies, gears, cams and couplings are also employed to transmit power. eg. The self propelled combine is a machine which employs most of the above power transmitting devices.

In some machines the belt drive is used to transmit power between two parallel shafts placed a short distance apart. In others a sprocket and chain drive is preferred, when the two parallel shafts to be operated

Being an agricultural country with 1/5^th of the world’s population of cattle and half of the world’s buffaloes. The cows and bullocks are the backbone of agriculture and play major role in the rural economy. India stands first in milk production in the world. Corresponding increase in human population, the per capita availability of milk is 145 gm/day which is far lower than the recommended level of 285 gm/day/head.

Importance of Livestock Management

• Provides milk and milk products. Milk is a perfect food as it contains proteins, fat, milk sugar, minerals and vitamins. It is the only source of animal protein in vegetarian diet.
• Livestock gives us meat.
• Provides farmyard manure

Vegetables: Three conditions shoul1d be met to be called a horticultural produce as a ‘vegetable’ viz.

• Vegetables are herbaceous plants
• They mostly serve culinary purpose
• They are also used in small quantity in a raw form.

Scenario

Area

• India is the second largest producer of vegetables in the world, next to China. India’s share of the world vegetable market is around 14%.
• India produces 188.28 m tonns

Potato (Solanum tuberosum L.)

Potato is the third most important food crop in the world after rice and wheat in terms of human consumption. Potatoes are an important staple food crop. Introduced into Europe in the 16th century by Spanish explorers, it is cultivated throughout the world including the Indo-Pakistan subcontinent.

Botanical Name : Solanum tuberosum L.

Family : Solanaceae

Importance

• Potato is an economical food, as it provides a source of low cost energy to human diet.
• For vegetable purposes, potato has now become one of the most popular crops in India and cultivated in almost all states and under very diverse agro climate conditions.
• Potatoes are a rich source of starch

Berseem is very important rabi season legume fodder and popularly know as the “King” of fodder crops.

Berseem (Trifolium alexandrinum L.)

Berseem, also called Egyptian clover, is an important winter forage.

Family : Leguminaceae

Importance

• It is quite nutritive and succulent highly pelatible. It has 20% crude protein and 70% dry matter digestibility
• Forage is also rich in calcium and phosphorus.
• Berseem cultivation changes chemical characters of soil

Sugarcane (Saccharum officinarum)

Sugarcane is an important agro-industrial crop of tropical and subtropical region of the world. Sugar industry is next to textile industry provide employment to large number of people. It is the main crop of earning foreign exchange. It shares about 2% GDP.

Family : Gramineae (Poaceae)

Importance (Second largest agro-based industry)

• It is cash crop used for sugar, Jaggery (Gur) and Khandsari.
• Green top is used as green fodder. Dry leaves used as mulching and as a fuel.
• Bagasse (By product) is used as fuel, for the production of fibre board, paper etc. and for power generation (electricity).
• Molasses is used in distilleries for the manufacture of alcohol and is also used as an additive to feed livestock.
• Press mud is used as soil amendments, organic manure

Cotton

Cotton is one of the most important fiber and cash crop of India and play a key role in economic and social affairs of the world. Cotton is referred to as “King of Fibres” and also known as “White Gold”. India is largest produces of accounting for 22% cotton in the world. Nearly 65 per cent of the cotton crop is grown under rainfed conditions. Cotton production, processing and trade provides livelihood to several millions of people.

Scientific Name : Gossypium hirsutum

Family : Malvaceae

Origin: Cotton has been used as a fabric in India from time immemorial. It has been cultivated in the Indus Valley for more than 5000 years before. The excavations of Mohen-jo-daro indicates a high degree of art in spinning and weaving with cotton at that time. It finds mention in the Rigveda, the oldest scripture of the Hindus. Manu also refers to it in his Dharma Shasta. India appears to have been the centre of an important cotton industry as early as 1500 B.C.

Five major oilseeds are groundnut, sesamum, Rapseseed and Mustard, linseed and castor seed. India has the largest area and production of oilseeds in the world. Indian vegetable oil economy is the fourth largest in the world next to USA, China and Brazil.

Importance

• Oilseeds are sources of oil, protein, carbohydrates, vitamins like Vitamin A, D, E and K and also contain 18 essential aminoacids and trace elements.
• Edible oils are next to food grains in Indian diet.
• Vegetable oils are mainly (95-98%) triacylgycerols which are made up of one glycerol molecule and three fatty acid molecules. Quality of oil depends upon the nature and proportion of the fatty acids present in three triacylglycerols.
• Vegetable oils have a number of industrial uses such as soaps, detergents, plastic films, metallic foils, Condiments, Cosmetics, Plastic, Polymers, Organic coatings, Printing ink, Oiled cloth

Pulses are edible seeds of the family Leguminosae, sub family papilionaceae, and are integral part of Indian diet. Indians consume 30 per cent of the world’s pulses, but domestic production of pulses has not kept pace with population growth. Pulses are called “poor man’s meat” as pulses are rich in protein, which is double the protein content of wheat and three times that of rice. Globally, 190 mha of pulses contributes to 5-7 mt of nitrogen in soils.

Pulse means

P = PEOPLE (major source of dietary protein)

U = UMBRELLA

L = LIVESTOCK (green nutritious fodder and feed)

S = SOIL (builder and restorer of soil fertility through biological nitrogen fixation and green manuring). E = ENERGY.

Introduction

India is the world’s second largest producer of rice, wheat and other cereals. The important cereals are-wheat, paddy, sorghum (Bajra), barley and maize etc. India is not only the largest producer of cereal as well as the largest exporter of cereal products in the world.

Foodgrain production (2019-20): 296 million tonnes

Scenario

Table: States producing maximum area and production of crops in India

Intra-operative complications

Although the phacoemulsification technique costs higher, it provides shorter surgical time and less complication than extracapsular lens extraction (49).

The most important intraoperative complications are anterior capsular fibrosis, radial tear of anterior capsule, posterior capsular rupture, vitreous prolapse and post-operative complications like uveitis and corneal oedema (50).

The production of ultrasound energy in phacoemulsification is associated with heat generation that can result in damage to ocular tissue, in particular the corneoscleral wound site. Thermal damage to the corneo-scleral wound site may result in difficulty with wound closure and consequent risk of wound leakage, as well as damage to the adjacent corneal stroma and endothelium, fistula formation, and the induction of high degrees of post-operative astigmatism. The loss of adequate flow of irrigation fluid around the phacoemulsification tip is the key factor in the development of phacoemulsification-induced thermal injury. 

Good cataract outcome depends on pre-operative selection of patients, the skills and knowledge of the eye surgeon, the surgical technique, the surgical facilities and environment, the post-operative care and the optical correction provided.

Preoperative Procedures

Owners are advised to instill antibiotic eye drop such as Moxifloxacin @ two drops b.i.d. for 7 days and eye drop tropicamide @ two drops b.i.d. for 2 days before the cataract surgery for proper dilation of pupil. Non-steroidal anti-inflammatory eye drops such as Flubriprofenis started t.i.d on the day before surgery. Further, tropicamide (1%) used as mydriatic agent is instilled 30 minutes before operation at the rate of two drops every 5 minutes in the eye to be operated. 0.5% povidone iodine drops are instilled on cornea prior to surgery.

All animals with cataract are not suitable candidates for surgery. Pre-surgical assessment of a candidate is essential to make a safe judgement for surgical procedure to perform lensectomy. Failure in canine cataract surgery can be associated with poor case selection. A thorough ocular and physical examination should be performed to rule out other ocular diseases prior to cataract surgery. The cataractous lenses in both eyes must be mature to cause functional loss of vision. (24).

The following prerequisites should be fulfilled before cataract extraction is recommended (6):

1. The affected eye should have a significant visual deficit.
2. For the patient to regain vision, its retina must be healthy and functional. if the fundus cannot be examined thoroughly (because of the cataract), retinal function should be evaluated with electroretinography (ERG) to ensure that retinal degeneration is not present as the patient history, signalment, and the speed of pupil contraction

The speed with which changes in the eye can take place is challenging. Ophthalmic problems do not lend themselves to casual examination or ‘trial and error’ therapy. Therefore, to perform safe cataract surgery with good quality outcome, uniform minimum standard of diagnostic and clinical practice needed to be in place.

Although cataract can be diagnosed by routine gross examination ofthe affected dog even then it is mandatary to develop a routine ophthalmic examinations in a consistent and organized manner to make a confirmatory diagnosis and plan the surgical technique for a favourable prognosis. A sequential examination starting right from history up to electroretinography may be performed as under:

History » Gross Examination » Menace response test » Obstacle course test » dazzle or photic blink reflex » Light induced pupillary reflexes (direct/ consensual) » Corneal reflex test »Schirmer’s tear test

(A) Anatomy of Lens

The lens is anoptically clear, avascular, biconvex structure of crystalline appearance with an anterior surfaceless curved than the posterior surface, placed between the iris and the vitreous. It is suspended by the suspensory ligament of the lens which is attached to the ciliary body and equator of the lens.

The lens consists of a central nucleus surrounded by the lens fibres and anterior epithelium, encapsulated in an elastic lens capsule. The anterior surface of the lens is in contact with the posterior surface of the iris whereas posterior surface is in contact with the vitreous. As the adult lens does not have a blood supply, its metabolic needs are met by the aqueous humour. The lens is composed of 65% water, 35% protein with scant amounts of electrolytes. The proteins can besubdivided into soluble proteins,

Cataract is a common cause of visual impairment and blindness in dogs and has a wide variety of aetiologies, as well as the disabling effect on the animal. Cataracts present important welfare considerations for the owner. Visual impairment in dogs may lead to increased nervousness, aggression and reluctance to exercise, all of which may adversely affect the owner-pet relationship (1). The only effective mean of treatment for cataract is surgical extraction of diseased lens (2).

Although vision is one of the important faculties for any living individual, dogs have very well developed olfactory lobe and have great sense of smell. They can move about easily in limited area familiar to them even with impaired vision. Cataract surgery was therefore not a common procedure in animals for many years. Quite often however,

With recent work it has become clear that bacterial societies are very complex. Gene expression in bacterial communities are heterogenous. The heterogeneous gene expression contributes towards the biofilms in fluctuating environments which needs to be understood.Technique like single-cell analysis can help in the investigation of more complex communities. Recently, Jahid and Ha, (2012) have written a review on microbial biofilms of produce and the future challenges to food safety many outbreaks have been observed involving food- borne pathogens. Therefore, there is an urdent need for the safety of foods especially against microbial attacks and biofilm formation as they cause a risk to public health. Medically, the pathogenic microorganisms form biofilm- associated with the epithelial or endothelial lining which are embedded in the lungs, intestinal or vaginal mucus layer, the teeth or other medical implant surfaces or formed intracellularly (Dewasthale et al., 2018). Teichoic acids are characteristic major components of the cell surface in Gram-positive bacteria.

Ali Demirci et al., (2014) studied the reactors with biofilms which are used to produce many value added products. These include organic acids, alcohols, enzymes, antibiotics, bacteriocins and many more. Many bioreactor designs favor the biofilm formation in a reactor. The biofilm reactors are utilized for fermentation and bioconversion of large amount of biomass. Recently, the biofilm reactors have been applied for production of many value-added products with novel designs. According to Ercan and Demirci (2015) the biofilms can cause both detrimental and beneficial effects in the environment. Biofilms in bioreactors has many advantages due to the membrane fouling which reduces the cost. Higher biomass density can be utilized and the operation is more stable.Biofilm reactors are commercially being utilized for waste water treatment, bench and pilot-scale production of value-added products. In order to run the biofilm reactor at optimum conditions it is important to understand the fundamentals of biofilm formation, the different properties

Acinetobacter baumannii is an opportunistic pathogen giving rise to nosocomial infections causing threat to public health. Studies of biofilm-forming genes was done in A. baumannii isolates by PCR technique. To study the relationships of genes a technique based on PCR sequences along with multilocus sequence typing (MLST) were utilized (Saeed et al., 2020). Goudarzi, Mehdi et al. (2019) studied the genetic diversity and biofilm formation analysis of Staphylococcus aureus causing urinary tract infections in Tehran, Iran. The biofilm forming and adhesion encoding genes were studied along with distribution of different agr and spa types in S. aureus isolates by PCR screening and multiplex PCR. The workers found that the ability to produce biofilm was higher among MRSA strains as compared to MSSA strains. The most prevalent biofilm forming gene was icaD (77.3%), followed by icaA (76%), icaB (57.3%) and icaC (50.7%). Acinetobacter baumannii is a nosocomial pathogen which is commonly present in hospitals and is a causal organism of many diseases. A. baumannii isolates have been known as multidrug-resistant (MDR). For controlling such serious organism only molecular techniques have been found to be effective. 

Joana et al.(2016) have written a critical review on biofilms and have discussed newer methods to study biofilms. These have given a deep knowledge on the physiology, structure and composition of biofilms. More polar amino acids were present in ABPs but QSPs were made up of higher number of neutral amino acids.This helps in recognition. Web application WebLogo help in generating sequence logos (Crooks et al., 2004). The uncharged polar amino acid is present at the first, third and fifth positions.The basis of SVM model is on the amino acid composition of the peptides. The Weka model is based on selected eight inputs which is trained on the NT5 dataset and is accurate, sensitive and specific.Peptide drugs are FDA approved and a total of 242 sequences of biotech peptides/proteins are available at the Drug Bank database. To identify potential anti-biofilm activity for characterization the peptide sequences are submitted on the module of dPABBs. The prediction outcomes are displayed under the ‘Putative ABPs’ section(http://ab-openlab.

According to Fereshteh et al. (2020) microorganisms use biofilm to protect themselves against the harmful effects of the host body immune system and the surrounding environment. This helps them to survive against the anti-microbial agents. Inhibition of bacterial biofilm formation is very time consuming and expensive. Newer computational tools have been found to be a good option to predict the inhibition of biofilm peptides. In a computational prediction tool a large number of peptide sequences can be screened to select the peptides for validation. Vectors are extracted from the peptide primary structure and classification algorithms are carried out which includes SVM, random forest and k-nearest neighbour to evaluate their performance. Using a combination of features, helps in good evaluation. National Institute of Health (NIH) has found out that 80% of bacterial pathogens form biofilms and their multicellular structure makes them resistant to the hosts’ defense systems and traditional antimicrobials than planktonic bacteria. Recently, the use of Antimicrobial peptides

Biofilms are resistant to antibiotics even at high concentrations (Costerton et al., 1999).This could happen when the diffusion of the antibiotic within the biofilm matrix is inefficient and results in slow growth rate of biofilm cells (Davey et al., 2000), there could be the presence of persistent cells and antibiotic-resistant small-colonies (Hogan and Kolter, 2002; Kolenbrander, 2000).Studies have proved that antibiotics can inhibit biofilm formation. An antibiotic azithromycin, is known to inhibit Pseudomonas aeruginosa biofilm. Biofilm colonies become resistant at higher concentrations of the antibiotics whereas at low concentrations these can be induced (Mah and OToole, 2001). P.aeruginosa is commonly present in the lungs of patients infested with cystic fibrosis. The clinical isolates show resistance to azithromycin (MIC>64 pg/ ml).However, low doses of azithromycin have shown improvement in lung function in patients with cystic fibrosis (Borriello et al., 2004). If antibiotics are given at low concentrations (below the MIC) than it induces biofilm formation in a variety of bacterial species. Sub-MIC concentrations of tobramycin can induce biofilm formation in P. aeruginosa. The use of antibiotics in agriculture, as growth promoters have shown to expose bacteria to low levels of the drugs and has caused havoc (Smith et al., 2002). Rachid et al. 

According to Li and Tian (2012) a pure-culture planktonic growth of bacteria is rarely found in natural environments.There is a physical interaction between the bacterial cells in biofilms (Kolenbrander, 2002; Watnick and Kolter,2000).The bacteria can organize into groups and can form well-organized communities. They also communicate for coordinated activities (Davey and O toole,2000; Watnick et al., 2000; Nadell et al., 2009). Quorum-sensing mechanisms are common in prokaryotic and single-celled eukaryotic organisms like fungi (van Bodman et al, 2008; Sordi and Muhlschlegal, 2009). For any biofilm structure to develop a high level of cell density is important (Kolenbrander et al., 2002; Kuramitsu et al., 2007 and Webb et al., 2003) and also for checking the effect of antibiotics against planktonic organisms in exponential growth phase using MIC and MBC.This can predict the antibiotic efficacy against rapidly dividing bacteria in acute infections. Papanna, Shobharani and Agrawal Renu (2010) studied the interception of quorum sensing signal molecule

The biofilm formation is usually assayed by using Congo Red Agar (CRA) plate test. According to a method developed by Freeman et al., (1989) the isolates are stored in nutrient agar slants and screened for biofilm formation ability using CRA plates. Biofilm forming strains are observed as dark black colonies while others as red colonies on the CRA plates. Recently, the concept of these biofims have changed with new imaging technologies, biochemical methods and molecular ecosystem biology tools. A biofilm structure can be observed in 3-D form to the nano-scale level (Neu and Lawrence, 2015). A lot of studies are being conducted on the physiology of the biofilm cells, the genotypic and phenotypic variation among the biofilm community, as well as the biofilm metabolome, proteome and transcriptome (Raes and Bork, 2008). This will help in the the development of efficient methods to control deleterious biofilms (clinical biofilms, food contaminants, biofouling on industrial equipment and on ship hulls) and to enhance and modulate beneficial ones

Biofilms play an important part in biotechnology, immunology, biofouling and biodeterioration (Fleming and Wingender, 2001; Dunne, 2002). When the pathogenic cells adhere to the surface, it has been found that the transcription of the EPS genes get stimulated (Dunne, 2002). If EPS gene expression are monitored it can provide a good understanding of biofilm phenotypes (Allison and Sutherland, 1997; Helm and Naumann, 1995; Petersen et al., 2005). EPS serves many functions. It also enables the bacteria to capture nutrients (Pontefract,1991).The formation of biofilm goes through a mechanism which is different from species to species. Even the matrix thickness can be different from 0.2 to 1.0pm depending on the species and doubling time of the cells as thickness of 10 to 30 nm has been found in some bacteria species (Sleytr,1997). The cells secrete polysaccharides, proteins, nucleic acids and glycoproteins. Adherence on solid surfaces by microorganisms is a very complicated process that depends mostly on extracellular molecule production (Czaczyk and Myszka, 2007). The biosynthesis of EPS provides an optimal environment in which genetic material between the cells can be exchanged. This is needed for cell identification and the antigenic properties are helpful in serological characterization of the cells. Among the various compounds of extracellular carbohydrates are acetate esters, pyruvtes, formates, succinates, polysaccharides and proteins (Sutherland, 2001a).

Microbial life abounds on a solid substrate. Water and some nutrients are sufficient to allow the microbial construction called biofilm. Biofilm-associated infections (BAI) can enhance chronic infections in which the bacterial pathogens can persist causing cross-contamination of the food products.

Giaouris et al. (2014) worked on the meat processing and biofilm formation by foodborne bacteria. Work on seafoods has been well worked by Mizan et al. (2015). Habimana et al. (2010) studied them in feed industry on Salmonella versus host resident flora strains. Lin et al. (2017) have studied the characteristics of some food borne pathogens. In a study by Rao et al. (2020) cold atmospheric plasma can be a solution to prevent biofilms.Ferriol-Gonzalez et al. (2020) worked out that bacteriophages can be helpful to remove biofims. According to Przekwas et al. (2020) in early stage of growth of the biofilm use of ascorbic acid can be helpful for the removal of biofilms. Apples can be protected from pathogenic bacteria by protecting them using harmless bacteria. It leads towards the development of alternative foodborne-pathogen-control strategies. Listeria monocytogenes is a big concern in the NE part of India.

There are many bacteria and fungi which produce biofilms. These are made up of living, reproducing microorganisms. These microbes form communities and adhere tightly to the surfaces and are resistant to many antibiotics. Many pathogenic microorganisms form biofilms which are difficult to be removed and are harmful.Such microbial colonies produce an extracellular polymeric substance (EPS) to protect them. The dental plaque was the first documented evidence of microbial biofilms. When such microorganisms get a moist environment they attach themselves to any object and reproduce forming an attachment by secreting a slimy, glue-like substance. It is possible with metals, plastics, natural materials, medical implants, kitchen counters, contact lenses, walls of a hot tub or swimming pool. Initially it was the investigation of many scientists to show the presence of biofilms

Beneficial effects of biofilms have also been shown (Rosche et al., 2009) especially in agriculture (Bogino et al., 2013; Berlanga and Guerrero, 2016) where it can be utilized as a biological control agents. They are used as biofertilizers to enhance crop production (Timmusk et al., 2017), hazardous pollutants can be removed (Irankhah et al., 2019). 

Sustainability does not denote a fixed state of things. It is a dynamic phenomenon: a phenomenon that tends to advance towards a higher state of being. The range of a journey of sustainability extends from nothing to everything, from a simple system to a more complex system, or from an unstable or less stable system to a stable or more stable system. Speaking in ecological terms, the transformation of unproductive desert land into a forest in ecological climax over time is how the phenomenon of sustainability works.

The term ‘sustainable development’ was first of all used in 1980 in the World Conservation Strategy (IUCN-UNEP-WWF 1980). However, this term was brought into the focus of the world for the first time in the United Nations World Commission on Environment and Development (WCED) Report, popularly known as the Brundtland Commission Report Our Common Future in 1987. Sustainable Development in the WCED Report has been defined as Development that meets the needs of the present without compromising the ability of the future generations to meet their own needs.

Most of the ecosystems prevailing on Earth have ceased to be virgin. They are now modified following anthropogenic designs. The Blossoming of a community in its climax stage is a rare sight. As human intervention with nature has gone on increasing, all types of biodiversity - genetic, species and community, and alpha, beta, and gamma - have been put under stress. The Earth has already lost much of its diversity due to anthropogenic factors and now it seems to be under severe stress due to climate change, which is also largely due to human-induced environmental disruptions.

Continuous loss of biodiversity at an alarming rate is posing a serious threat to life on earth. With this dismal state of the environment, we cannot usher in a sustainable future. We do not have the right to snatch the future from our younger generations. The Earth belongs to our children more than it does to us. The Earth belongs to future generations more than it does to present generations. Conservation of biodiversity is a matter of ethics. Ethics has the human face of biodiversity. Economic attributes of biodiversity have importance, but ethics of life 

A large number of genetic resources, species, and ecosystems are under severe threat. Many species have gone extinct and many more are being pushed towards extinction. Most of the ecosystems have also gone into what we can call functional extinction. The major factors becoming threats to biodiversity are anthropogenic. Human activities, in essence, are not benevolent for biodiversity to flourish in natural systems. Burgeoning human populations are the root cause of biodiversity destruction. Changing human lifestyles fed by a materialistic economy are further acting as catalysts for the ever-increasing human populations to destroy biodiversity evolved over millions of years amid terrestrial conditions favorable for the origin and prevalence of an astonishing variety of life forms on Earth.

There is hardly any threat to biodiversity due to natural factors except those inherent in the designs of natural evolution. A species at a certain point of time in its evolutionary history is destined to vanish, but the void in nature created due to this loss is filled by the evolution of new life forms. Not only the void is filled, the nature gradually goes on enriching itself 

Nutrition is the basis for life to prosper and sustain in the biosphere. There are two modes of nutrition in all species: self-nourishment and crossnourishment. Self-nourishment goes on in the category of organisms known as autotrophs. Cross-nutrition is maintained by the category of consumers categorized as heterotrophs. The autotrophs nourish themselves by utilizing inorganic molecules and energy available in nature, while the heterotrophs derive the nutrients that the autotrophs ‘manufacture’ for themselves. In other words, the heterotrophs derive nutrients from organic molecules. These organic molecules are derived either from the autotrophs directly or from the consumers dependent on autotrophs.

Autotrophs derive energy in its free form (e.g. light) or that available in inorganic molecules (e.g., CO, 

All of nature’s biodiversity is not visible. Biodiversity can also not be studied and/ or understood by looking at and analyzing it with the naked eye. A great proportion of the planet’s biodiversity flourishes in the ecosystems not directly accessible to us and the organisms in the sizes our eyes cannot record. The soil biodiversity is more interesting and more varied than we have understood and appreciated. The biodiversity in the soil - together with the physical environment - constitutes what we can call the pedosphere. Biodiversity in the pedosphere is distinguishable from that of the biodiversity above the soil surface. One is nonplussed by an understanding of some of the unbelievable features and functions of the pedosphere biodiversity.

The Convention on Biodiversity (CBD) held on the occasion of the historical Earth Summit in Rio de Janeiro in 1992 underlined the significance of biodiversity conservation for various tangible and non-tangible benefits as well as one of the key factors for sustainability. However, the conservation of soil biodiversity for realizing sustainability

Agrobiodiversity is a key resource for humanity. All of the food retirements humanity depends on are fulfilled by agrobiodiversity. Not only this, fodder, fiber, firewood, and many other basic needs of humankind are also met by agrobiodiversity. Human’s dependence on agriculture - not only for survival and sustenance but also for socioeconomic progress, maintenance and celebration of cultural ethos, physical, intellectual, emotional, ethical, and aesthetic development, and psychological contentment and happiness - is inevitable.

Agrobiodiversity is critical for food security for the entire humanity as well as for the food sovereignty of a country. If we are to usher in a sustainable future - that is, a future to be witnessed by healthy, vibrant, and happy humanity (Singh 2019) - there is no choice other than protecting, conserving, and augmenting agrobiodiversity.