Ask any woman “who you are?’ and she will immediately reply ‘I am a human being’. This was absolutely correct answer once upon a time but now it seems to be inaccurate and uncertain with the recent advancement of modern molecular techniques. The accurate answer is “Yes, I am a human being with ten percent of my own body cells and remaining ninety percent cells belong to microorganisms”. Microorganisms which are not visible by our naked eyes, they are omnipresent on the earth and our body. Bacteria, commonly known as bugs or germs, constitute the majority of these microbes associated with human species. An adult human has approximately 100 trillion cells [one trillion is 1,000,000,000,000 or 1012] whereas rough estimates show that the total number of bacteria coexisting exceeds more than 200 trillion per person. Current estimates imply that there are more than ten thousand different types of germs present in and on our body. The full array of these small microscopic commensal organisms living with the human body is broadly termed as ‘Microbiome’. It is a misconception that bacteria only harm to us, not all of these microorganisms are harmful to our wellbeing and actually many have established an essential connection with our body. In reality, both human and bacteria get benefits resulting in a symbiotic association. Microbiome coexists with different organs like skin and the mucosal tissues such as nasal passage, oral cavity, gastrointestinal tract, and urogenital tract. Different people harbour drastically diverse collections of bacteria with a variation in their count. Several factors, such as age and sex, dietary lifestyle, behavioural and hygienic practices, immune and hormonal status, and genetic make-up of a person influence the composition of the microbiome. It is a fascinating observation that microbiome of 60 belly buttons, found 2,368 bacterial species out of which 1,458 were new to science. Ninety-two percent of the bacteria discovered on belly buttons for just about ten percent of individuals indicates the nature of diversity of the human microbiome.
Collection of human and microbial cells together is also responsible for the physiological character of an individual. Each bacterium has its own genetic material containing thousands of genes and the presence of thousands of different bugs as microbiome substantially constitutes more genetic diversity. The human genome has estimated 20,000-25,000 protein-coding genes that is repeatedly revised since years with the help of gene finding and sequencing methods. Due to microbiome, human has a larger gene pool due to additional genetic information which attributes to the physiological character of an individual. For example, the human gut microbiota carries approximately 150 times more genes than found in the entire human genome.
Several research studies have revealed that the microbiome has an important function in human health and disease. The relationship between microbiome and human ensures proper development and maintenance of various processes within the human body. Drastic changes or an imbalance in a person’s natural microflora leads to ‘dysbiosis’ of the microbiome. This condition favors the overgrowth of harmful microorganisms leading to inflammation and infection. Dysbiosis is also implicated in the inclination towards severity for a wide range of diseases, such as allergy, asthma, inflammatory bowel disease, obesity, diabetes, and many noncommunicable diseases. Emerging research implies that communication between the atypical gut microbiome and brain may result in the development of anxiety, depression, altered cognition, and autism. Due to availability of modern research tools such gene amplification technique i.e Polymerase chain reaction and newer large scale gene sequencing methods, it is extremely easier now to investigate the microbiome of an individual at a very low cost. Microbiome analysis has added diagnostic value as it predicts and provides a better picture for the diagnosis of the disease.
Women and men have many things in common; nonetheless, there are significant biological and behavioural differences between them. Gender affects a wide range of physiological functions. One small example is the acidic nature of the skin which is different for the men and women, and that probably helps to nurture different microbes on their skin. There are many physiological differences which have an impact on a wide range of diseases of cardiovascular, pulmonary endocrine, and immune systems. Gender is also known to influence the efficacy of medicines which we take to cure diseases. The uniqueness of women’s body in the human species is the possession of special reproductive organs and its functioning. In contrast to these distinctive features, the microbiome of women is obviously different from men to a great extent. Therefore a lot of attention is focused on women-specific organs and its microbiome.
Dr. Milind S. Patole & Nitin Bayal
Dr Milind Patole is Scientist ‘G’ at the National Centre for Cell Science, Pune. Nitin Bayal is Ph.D. scholar at National Centre for Cell Science, Pune