Lecture 02

Added: 2026-05-12

[00:00:01][music] [music] Uh good morning everyone. Uh so again uh I'm here again. Uh my last lecture we talk about the history of microbiology and we end up with uh little application of microbiology especially the modern microbiology where we [clears throat] talk about the uh use of modern microbiology or biotechnology applications. We stop there but just to continue from the same uh before we uh enter into the new topic of microbial diversity. So as far as the microbiology applications are concerned uh we have a lot of microbial uh pathogens which can be used to uh these pathogens can be used in order to uh make as industry uh and so uh the name is given as a biotechnology uh using the microbial world transform into the technology for the benefit of the society leading to a new emerging area called biotechnology. So how microbiology from look into in 1500 and 1600 in the century now in 21st century how it evolved in order to uh form a new technology emerged from the field of microbiology or the field of microbes which includes all viruses, bacteria, fungus and all. Well, so uh now we start a new uh topic today uh the microbial diversity and systematic classification and modern methods and concept. Uh dear students uh uh this is basically uh very important area because until we learn the microbial diversity and the classification system uh in modern method it is very difficult for us to uh to to to understand the microbial word.

[00:02:11]the millions and trillions of microorganisms all across you know around us.

[00:02:17]How do you name them? How do you classify them? Uh how do you identify them? This these are the some major issues uh or major uh basically questions which need to be addressed.

[00:02:31]So in in order to understand the microbial diversity and systematic classification uh the the importance of this topic is that to know which microorganism is characterized with certain features causing some disease are benefit for fermentation for wine productions for bread productions like fungus cycroisia for example Are they harmful or useful or how can we engineer these microorganisms?

[00:03:06]All right. To in order to uh make them useful.

[00:03:12]Then the concept of uh microbiota or microbiome is again is very important because whole microbiome, gut microbiome, oral microbiome or any microbiome even mud microbiome, soil microbiome, environmental microbiome could have some significance. So in order to understand what is this microbiome is total made made of what are the different microbial flora micro microorganisms present in this microbiome can be used through several techniques. So we call modern methods some traditional methods uh some some some new concepts in order to learn. So we'll learn in this in this topic we learn all these things.

[00:04:00]Well, the vast word of microbial diversity, diversity in the bacterial population, diversity in the fungus population, diversity in the virus, diversity in protozone, diversity in algae. So, you know, within the domain of each we have a lot of variations even single species.

[00:04:21]For example, if you talk about the E.coli, E.coli may have a hundreds and thousands of different strains. How these strains are diversified? how these strains are different. So these things we we'll study it. Suppose you pick up the E.coli stain from clinical isolate or from environmental sample then this E.coli may be different from the other E.oli although both are escalia similarly clapsula neoni or seduma serenosa. So each of these species beyond the species we have a lot of variation also. So see the level of variations and to comprehend the whole and to understand the whole diversity microbial diversity is very very important. So what are the tools to understand what are the what are the parameters to to learn it and to identify these is very important.

[00:05:09]Now the microbes uh are invisible majority. Now 60% of earth microbiome are the biomass right is basically uh constitute of the majority of the living matter on our planet demonstrating their fundamental importance to global ecosystem.

[00:05:32]uh then procarotic cells the estimated number of the procarotic cells globally representing an almost incomparable uh abundance of the microbial life.

[00:05:47]There's a lot of different microorganisms are being present. Then 99.9% almost uh undiscovered microorganisms.

[00:05:59]Undiscovered microorganisms means like microorganisms which are uh not uh known not not not aware about it they cannot culture. So the problem with this we have majority of the microorganisms which are basically non-culturable which are hidden which are not aware about it. We are not aware about it. So how to understand these microorganisms is through a new technologies. We'll discuss this why study the microbial diversity as I have told you earlier the microbial diversity to study the microbial diversity is important because until unless we understand their diversity and their each and every species and genera fila class right to know what about it we cannot work on it we cannot learn what these microorganisms are some medical breakthroughs. In medical breakthroughs, the microbes serve as a primary source of antibiotics, life-saving drugs like penicellin, empasylene and have revolutionized the modern medicine from penicelline to modern broadspectctrum antibiotics. Now the microbial diversity continues to provide a new therapeutics and compounds for treating the resistant infection and emerging diseases.

[00:07:24]So this is the medical breakthrough of policy. So there's a category of microorganisms which are basically causing the disease as well as preventing the diseases through production of the various antibiotics or antimicrobial agents or compounds. The industrial application of the microorganisms also the microbial enzymes powers numerous industrial processes from the food production to textile manufacturing and these biological catalysts offer the environmentally friendly alternative to harsh chemical processes enabling sustainable manufacturing practices across diverse industries.

[00:08:05]Well, sustainable energy the microorganles.

[00:08:11]This is the next generation biouels which is the one of the major challenge before us offering the renewable alternative fossil fuels through the possible like fermentation and bio gas production microbial diversity enable clean energy solutions and that reduce our carbon footprint.

[00:08:33]Environmental solution is also uh one of the area the bio remediation uh harness microbial capabilities to clean up environment pollutant from oil spill to heavy metals contamination. So you can you can develop you can engineer some microorganisms. You can identify certain microorganisms which can uh which can clean the spill oil spill which can degrade the oil on the sea or on the ocean uh or are any water bodies and these natural processes offering cost effective and environmentally sound approaches to restoring the damaged ecosystem. Now these microbial flora or microbial word is basically help us to to [clears throat] understand how we can control all these things.

[00:09:29]The microbial word. The inc in incredible diversity of microbial life including bacteria, viruses, fungus and all. From simple bacteria to complex ara from beneficial fungi to intricate viruses each representing unique evolutionary solution to the life challenging right how the classical method and the modern method. So first we'll talk about the classical method in microbial systematic classification. Now before we go that let me clear you there's the word classification identification and characterization.

[00:10:06]So the classification means you classify the bacteria viruses fungi in different classes fila order and different hierarchies. Now identification what are the basis of identification of these microorganisms to be classified into different group class and all and then to characterize it. So all these three thing classification, identification, characterization are hand in hand and characteristic features are identified right are we call the some manual characteristic features are identified which help these microorganisms to identify and to keep it into certain class order filer kingdom and so on. For example, whether the microorganisms are the living organisms is belong from animals or plant or microbial word, right? Are among the microorganisms from bacteria, virus, fungi, protozoa, algae, fungus and so on. So all these kind of a classification based on certain characteristic features and these characteristic features to be identified. So classical methods help us to identify these characteristic features.

[00:11:13]For example, morphology and cultivation.

[00:11:15]The early foundation in early microbial foundations microbial world foundations the simple morphology is one of the major parameters. How we can look into the morphology whether the bacteria are the spherical bacteria are the long elongated they are spiral they are different shape different colors right so all these morphology and colony shape colony structures textures can be identified and based on these simple visual screening of these microorganisms right looking at the colony size looking the color looking the texture will help us to uh categorize the microorganisms into different categories, different classes, order fila based on these unique characteristic features.

[00:12:01]Now then come to the nutritional requirement. So what is the nutritional requirement? Nutritional requirement means the micro different microorganisms have a different nutrition, right? Based on their nutrition value, based on their nutritional requirement, based on their metabolic processes which metabolize different nutrition. For example, some of the microorganisms they grow on the carbon sources like a dextron, sugar, glucose. Some of the microorganisms they grow in the presence of salt. Some of the microorganism they they they ferment the fructose, some sucrose, some glucose. So basically depending upon the metabolic processes, metabolic setup of microorganisms they utilize the nutritions. So indirectly nutritional requirement is also one of the indication of the microorganisms to be categorized into different categories.

[00:12:58]Then pure culture isolation. So culture characterist characteristics is again now in case of culture characteristics you have to know what are the different culture characteristics. Again these things are quite related because if you have a different nutrition, different carbon source, different energy sources to provide the microorganisms. So different for example bacteria need a different media bacteria need a different culture conditions virus need different culture conditions fungus need different culture condition. So having a different culture conditions you can have identified different different microorganisms to be categorized into different uh order class and different hierarchies.

[00:13:35]Now the photypic classification challenges uh has a major limitations.

[00:13:42]For example, morphological convergence the similar environmental pressures often produce a similar cellular form of across the unrelated lineages. So in certain cases uh these microorganisms morphologically same. So sometime it is very difficult for you to categorize them into one group or to other group but they are same. For example, if you talk about the caucus is spherical all these spherical microorganisms they are on the same category. So you keep them into one class or one group. But the other microorganisms which are also spherical how to keep them into the same group are different group is a big challenge. So these are the some limitation of the morphological. So you should have a number of the different characters involved during these morphological coverage. Phenotypic plasticity what does it mean? So many microbial traits right proved highly variable depending on the environmental conditions. For example, some of the microorganisms they have uh chain adapt different conditions and having adapted different conditions they can change. So they make a confusion whether you keep it into one category or into another category. So making consistent classification extremely difficult for scientists to to to keep them into one class group or one hierarchal uh status.

[00:15:04]Uh limited resolutions phenotypic approaches uh couldn't distinguish between closely related species or identify identify cryptic diversity within the morphological similar groups.

[00:15:18]So these are some challenges with the morphological or phenotypic conditions.

[00:15:24]Now historical uh historical milestones uh during the classifications uh the lenin system of classification adapted for the microbes were were the historical benchmark in 1753 Lenin foundations uh initiated that is called in established the bio uh meal or bomial nomen nomenclature. So it means the nomenclature of these microorganisms by giving two name bio means two two names nomenclatures. Now the plant and animals providing the hierarchal framework that would later be adapted for microbial classification.

[00:16:09]Okay. In 1872, bacterial classification starts. Uh the uh funin and corn the first applied systematic classification of bacteria. He was a scientist uh establishing genus and species. So the the identification or the giving the nomenclature of a genus of a species or genus and species of individual is started in 1872 uh by funant corn. What does it mean? It means for example escarishia coli. So escarishia is a genus coli is a species.

[00:16:45]Now under the genus escarishia you can have a number of different species by found for example seduminasa uh seduminas putita and there are many more. So under the general genus of acidas you can have a different species.

[00:17:00]So you have to identify some characters which are related to the common genome genus and then unrelated characters in the species.

[00:17:10]So establishing the genus and species uh designation uh you know given based on the several morphological characteristic features. Uh then in 1923 the very recent uh in history of classification the buggies manual was standard benchmark for the classification. And the first edition of Bergy's manual uh determinative bacteriology uh provides this uh standardized classification criteria through still base primarily on the phenotypic trait. Now these are all conventional method of classification where the phenotypic expression and morphological and cultural and uh nutritional and metabolic conditions are to be considered into uh characters identification. uh in 1980s a molecular revolution came and in molecular revolution even the species beyond the species can also be identified. Now the integration of the molecular techniques began transforming the microbial microbial systematic revealing the inadequacies of the purely morphological approaches and these morphological approaches are basically uh help us to to to understand what are the basic uh criteria for this.

[00:18:26]Now the visible uh tip of the microbial iceberg the classification cultivation methods revealed only the fraction of a microbial diversity right uh like like seeing merely the tip of an enormous iceberg. So whereas the 99% and the majority of the microorganisms are invisible uh they cannot be cultured they cannot be seen they cannot be identifying. So to explore them is a big challenge right. The molecular revolution in the microbial diversity uh reveal reveal a new area where you can uh understand the what are the molecular methods and molecular tools which can help us to uh which can help us to identify exactly the microorganisms with the unique characters. Now as you have discussed earlier that the conventional method which are based on the cultural characteristics which are based on the you know the nutritional value which are based on the metabolic responses uh which are based on the staining which are based on several other these are all methods which are based indirectly where you can use the phenotypic expression.

[00:19:46]Now what is the phenotypic expression?

[00:19:47]Infinitive expression means the expression of the individuals bacteria, virus, fungus and other in order to show their characters uh related to individual microorganisms as a unique characters. So what the scientists do they enumerate these characters 1 2 3 4 5 6 based on different morphological right different different cultural different nutritional requirement and so on so forth and then they compare the other microorganisms with again enumerating the 1 2 3 4 5 6 characters and then they compare these two and they identifying these two microorganisms based on the percent similarity and percent differences. Now percent similarity and percent difference is basically uh help you to differentiate these two based on certain benchmark based on certain criteria. Okay, this much percent differences percent dissimilarity between these two microorganisms for example A and B. So we can keep A is a different group B in different group. Similarly the person similarity is reduced. So we can keep reducing the group and we can close bring them into the closed group or but these morphological characteristics through intuitive method or through some other method they may not be very reliable to exactly identifying the microorganisms based on the characteristic features morphological characteristic features and to keep them into one classification. Now what are the uh requirement of the classification is basically the reproducibility predictability right what are the predictability means stability and predictability means the characters which you identify for a one microorganism should remain be predictive in terms of like if other microorganisms being identifying from clinical isolates from environmental isolates from any water seage water uh baselines and water bodies then this organ Organisms if show similarity person similarity to this organisms earlier one then we can look into the person similarity characters. If the person similarity characters are same and they are predictable for example say for example color of the colonies.

[00:22:13]If the color of the colonies is a pinkish with a luster color then you say okay it is ecoy on certain media. Now if other organisms identify is also related closely related to the same color and texture of the colony it means you can predict yes these organisms may be of the same kind. So these are the conventional method which are taking uh into consideration in order to identifying the microorganisms and keeping the microorganisms into particular group and order.

[00:22:45]Now these methods are basically not very reliable. So in order to understand the uh exact microorganisms based on the molecular charact characteristic features to be kept in one individual organisms so that it may not be repeated again as a wrong organisms to be kept in the same group has to be taking has to be taken into consideration the molecular characters molecular characteristic features. Now the what are these molecular characteristic features? So molecular re this molecular characteristic features identifying through different molecular techniques. So we call the molecular evolution in the microbial diversity.

[00:23:26]Now uh the detail of this topic on molecular evolutions in the molecular diversity will be discussed in my next talk but just I can give you a brief introduction about it. We can have a DNA based molecular techniques where we understand the genotype. So there are the two thing one is phenotype and there is a genotype. So we'll talk about the genotype in the next lectures in the detail and then we'll discuss how the genotypic characteristic features will very precisely identifying these microorganisms from one to other. Thank you very much. We'll see you in the next [music]