14-Jul-2021: Scientists Track Behaviour of Intestinal Bacteria in Response To Chemical Stimuli
The mystery of how does the bacterial resident of the human intestine, the E-coli move towards or away from chemicals---a phenomenon called chemotaxis, has intrigued scientists for a long time. E.coli bacteria show chemotaxis in response to different chemicals present in human gastrointestinal tract.
Scientists have now found the condition that is most suitable for getting the best chemotactic performance. The new finding will help track behavior of E-Coli bacteria in response to chemical signals. The response of E-Coli to chemicals in the intestine bacteria plays a crucial role in the functioning of the human intestine.
Many organisms in nature respond to the chemical signal received from their environment by showing bodily motion or as chemotaxis. A sperm cell finds the ovum using chemotaxis. White blood cells that are needed for healing injuries find the site of injury or inflammation by chemotaxis. Butterflies also track flowers, and male insects reach their targets by using chemotaxis. Understanding chemotaxis involves how it is affected by various conditions present inside the cell or in the environment.
E.coli uses its run-and-tumble motion to migrate towards the region with more nutrients. The nutrient molecules bind to the chemo-receptors present on the cell membrane, and this input signal is processed by the sensing module of the signaling network, finally modulating the run-and-tumble motion of the cell. The adaptation module of the signaling network ensures that the intracellular variables do not deviate too far from their average values.
One important aspect of signaling network of chemotaxis is the cooperativity or clustering tendency of the chemo-receptors, which helps amplifying the input signal, and as a result, E.coli can respond to even very weak concentration gradient. Thus receptor clustering was known to increase the sensitivity of the cell. However, some recent experiments have shown that receptor clustering also causes fluctuations in the signaling network triggering scientists to explore conditions that activate the best chemotactic performance.
In a recent study, scientists from S. N. Bose National Centre for Basic Sciences, an Autonomous Research Institute established under the Department of Science and Technology, Govt. of India, have theoretically shown that there is an optimum size of the receptor clusters at which the E.coli cell shows the best-directed motion guided by chemical signal received from its environment.
The team led by Sakuntala Chatterjee took the first step in understanding how the response can be made most efficient by tuning the receptor cooperativity in the study published in Physical Review E (Letters).
To quantify performance, they measured how fast the cell climbs up the concentration gradient or how strongly the cell is able to localize in the nutrient-rich region. According to the team, good performance also means a strong ability of the cell to distinguish between nutrient-rich and nutrient-depleted regions in space. The team found all these measures reach a peak at a specific size of the receptor clusters.
They have shown this optimality is a result of a competition between sensing and adaptation modules of the network. According to the present work, as cluster size increases, sensing is enhanced, which improves chemotactic performance. But for large clusters, fluctuations also increase, and adaptation comes into play. The signaling network is now controlled by the adaptation module, and sensing plays a less significant role which brings down the performance. The study can improve understanding of chemotactic behavior, particularly of an organism forming the bulk of bacterial samples for experiments owing to its ability to replicate fast and adapt easily to change in its environment.
12-Jul-2021: Indian stem cell & developmental biologist part of WHO advisory committee on human genome editing
Indian stem cell and developmental biologist Prof. Maneesha S Inamdar has been part of the WHO Expert Advisory Committee on Developing Global Standards for Governance and Oversight of Human Genome Editing, which released two new companion reports providing the first global recommendations to help ensure that human genome editing is used for public health, with an emphasis on safety, effectiveness, and ethics.
The reports, released on July 12, 2021, contained a forward-looking Governance Framework for oversight mechanisms for research into and potential application of human genome editing technology at institutional, national, regional and international levels.
Professor Maneesha S Inamdar, along with her group, is conducting research at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, an autonomous Institute of the Department of Science and Technology (DST) that uses gene-editing tools to manipulate stem cells in vitro. This can generate disease models for scientific insight into human development and devising therapeutic strategies. She pioneered human embryonic stem cell derivation and use in India and has contributed significantly to national and international stem cell guidance documents, ethics committees, and training programs.
As part of the WHO Committee, she contributed scientific knowledge and perspective to provide guidance, expertise and support throughout the project for the conceptualization and development of the WHO Governance Framework and Recommendations on Human Genome Editing. Representing the LMIC countries in Asia, she contributed with the Committee towards ensuring that in addition to scientific considerations, procedural and substantive values and principles such as inclusiveness, diversity, equity, and global health justice identified by the Committee, informed decisions. She is a member of the Education, Engagement, and Empowerment (3E) subgroup of the Committee, and as part of the committee, she was also involved in making recommendations to the Secretariat and WHO Director-General on global governance structures for human genome editing, considering the relevant broader issues associated with oversight and governance of emerging technologies.
19-Mar-2019: WHO expert panel paves way for strong international governance on human genome editing
The World Health Organization’s new advisory committee on developing global standards for governance and oversight of human genome editing has agreed to work towards a strong international governance framework in this area.
Gene editing holds incredible promise for health, but it also poses some risks, both ethically and medically. This committee is a perfect example of WHO’s leadership, by bringing together some of the world’s leading experts to provide guidance on this complex issue.
Over the past two days, the committee of experts reviewed the current state of science and technology. They also agreed core principles of transparency, inclusivity and responsibility that underpin the Committee’s current recommendations. The committee agreed that it is irresponsible at this time for anyone to proceed with clinical applications of human germline genome editing.
The committee also agreed that a central registry on human genome editing research is needed in order to create an open and transparent database of ongoing work. The committee asked WHO to immediately begin working to establish such a registry.
The committee has invited all those conducting human genome editing research to open discussions with the committee to better understand the technical environment and current governance arrangements and help ensure their work meets current scientific and ethical best practice.
The committee will operate in an inclusive manner and has made a series of concrete proposals to increase WHO’s capacity to act as an information resource in this area.
The committee will develop essential tools and guidance for all those working on this new technology to ensure maximum benefit and minimal risk to human health.
Over the next two years, through a series of in-person meetings and online consultations, the committee will consult with a wide range of stakeholders and provide recommendations for a comprehensive governance framework that is scalable, sustainable and appropriate for use at the international, regional, national and local levels. The committee will solicit the views of multiple stakeholders including patient groups, civil society, ethicists and social scientists.
10-Jul-2021: The genome of a Salt-secreting Mangrove Species Decoded by DBT-ILS
Scientists at the DBT-Institute of Life Sciences, Bhubaneswar and SRM-DBT Partnership Platform for Advanced Life Sciences Technologies, SRM Institute of Science and Technology, Tamil Nadu have reported for the first time a reference-grade whole genome sequence of a highly salt-tolerant and salt-secreting true-mangrove species, Avicennia marina.
Mangroves are a unique group of species found in marshy intertidal estuarine regions and survive a high degree of salinity through several adaptive mechanisms. Mangroves are important resources for the coastal region and are of great ecological and economic value. They form a link between marine and terrestrial ecosystems, protect shorelines, provide habitat for a diverse array of terrestrial organisms.
Avicennia marina is one of the most prominent mangroves species found in all mangrove formations in India. It is a salt-secreting and extraordinarily salt-tolerant mangrove species that grows optimally in 75% seawater and tolerates >250% seawater. It is among the rare plant species, which can excrete 40% of the salt through the salt glands in the leaves, besides its extraordinary capacity to exclude salt entry to the roots.
This study published in the recent issue of the Nature Communications Biology reports the assemblage of a 456.6 Mb of the estimated 462.7 Mb A. marina genome (98.7% genome coverage) in 31 chromosomes derived from 88 scaffolds and 252 contigs. The percentage of genomes in gaps was 0.26%, thereby proving it to be a high-level assembly. The A. marina genome assembled in this study is nearly complete and can be considered as a reference-grade genome reported so far for any mangrove species globally and the first report from India”.
This study employed the latest genome sequencing and assembling technologies and identified 31,477 protein-coding genes and a “salinome” consisting of 3246 salinity-responsive genes and homologs of 614 experimentally validated salinity tolerance genes. The study reported identification of 614 genes, including 159 transcription factors, which are homologous to the genes that were functionally validated for salinity tolerance in transgenic systems.
This study assumes significance as agriculture productivity globally is affected due to abiotic stress factors such as limited water availability and salinization of soil and water. Availability of water is a significant challenge to crop production in dryland areas, accounting for ~40 percent of the world’s total land area. Salinity, is prevalent in ~900 million hectares globally (with an estimated 6.73 million ha in India), and it is estimated to cause an annual loss of 27 billion USD. The genomic resources generated in the study will pave the way for researchers to study the potential of the identified genes for developing drought and salinity tolerant varieties of important crop species of the coastal region that is significant for India with 7,500m of coastline and two major island systems.
About DBT: The Department of Biotechnology (DBT), Ministry of Science and Technology, boosts and augments the development of the biotechnology ecosystem in India through its expansion and application in agriculture, healthcare, animal sciences, environment, and industry.
About DBT-ILS: Institute of Life Sciences has a broad vision of carrying out high-quality multidisciplinary research in the area of life sciences. The goal is for overall development and betterment of human health, longevity, agriculture and environment. The stated mission of the institution is to work towards upliftment of the human society and generate skilled human resources for future India.
1-Jun-2015: CSIR succeeds in Whole Genome Sequencing of Holy basil (Tulsi) – A First Step to unravel the Secrets of its Therapeutic Potential
CSIR-Central Institute of Medicinal & Aromatic Plants (CSIR-CIMAP), Lucknow, has published whole genome sequence of Ocimum sanctum, the wonder plant ‘Holy basil’ or ‘Tulsi’, which is revered as ‘Vishnupriya’ and worshipped for over more than 3000 years through the sacred traditions of Hindu culture. This is the first report of complete genome sequence of a traditional and most respected medicinal plant of India, using a composite next generation sequencing technologies.
Considering the metabolic and therapeutic potential of this revered plant, the availability of whole genome sequence is the first step to understand and unravel the secrets of this ‘mother of all herbs’ and to provide scientific validity to the traditional claims of its utility in diverse medicinal usage.
Being the most popular household plant in India, ‘Holi basil’ or ‘Tulsi’ is traditionally used for the cure of several ailments. This herb is described as “The Queen of Herbs,” “The Incomparable One” and “The Mother Medicine of Nature” in the Ayurvedic text of Charaka Samhita. All parts of this legendary, divine and most cherished ancient herb (dried leaf, dried seed, and dried whole plant) are used in several systems of traditional medicine, including Ayurveda, Greek, Roman, Siddha, and Unani. It is used in the preparations to cure various diseases like bronchitis, bronchial asthma, malaria, diarrhea, dysentery, skin diseases, arthritis, painful eye diseases, chronic fever, insect bite etc. It has also been described to possess anti-fertility, anti-cancer, anti-diabetic, anti-fungal, anti-microbial, hepatoprotective, cardioprotective, anti-emetic, anti-spasmodic, analgesic, adaptogenic and diaphoretic actions. Many of the basil oil constituents have found applications as medicinal ingredients, flavors, fragrance, etc.
‘Holi basil’ or ‘Tulsi’ is rich in phenylpropanoids, terpenoids and their derivatives, and many of these are implicated for different therapeutic activities. The availability of the genome sequence now opens the possibility to identify genes involved in producing therapeutic molecules and to produce them in vitro. This will also facilitate identification of not yet identified genes involved in the synthesis of important secondary metabolites in this plant. Specific pathway related genes identified or mined in this genome could be used for the production of secondary metabolites following synthetic biology approaches. The development of molecular tools and genomic resources will accelerate molecular breeding and ultimately the utility of Holy basil in medical community.
The nuclear genome of Holy basil is the smallest (386 Mb) in the family Lamiaceae while the chloroplast genome (142,245 bp) is the smallest in the order Lamiales. According to the chloroplast genome similarity, O. sanctum shows maximum evolutionary closeness to Salvia miltiorrhiza, a plant of Chinese system of traditional medicine. Although, both these plants predominantly produce phenylpropanoids, and both have the identical diploid number of chromosomes (2n = 16), the genome size of O. sanctum (386 Mb) is a little more than half of the genome size of S. miltiorrhiza indicating that O. sanctum genome is more compact than that of S. miltiorrhiza.