Stress responsive gene bioprospecting studies from extremophilic and extremotolerant microalgae: characterization and functional validation of genes involved in acid, salt and thermal stress

Micro algae are diverse group of microscopic photo-autotrophic nonvascular plants with photosynthesizing pigments. They are unicellular and sometimes form extended chains with simple reproductive structures. These unicellular primary producers are dispersed throughout the photic zones of the ocean and accomplish major share of the primary production in the marine environment and account half of the primary production in the earth. They belong to both prokaryotes (Blue Green algae, Cyanobacteria) and eukaryotes (True algae). The phylogeny of microalgae basically depends on the traditional morphological identification. Morphological identification, based on the structure and arrangement of cell organelles, has limited application when environmental condition like salinity, pH, light, temperature, nutrient condition can change the structure of the cell. Recently more research has been carried out in the field of algal taxonomy, wherein many exciting molecular and ultrastuctural evidences has emerged. Due to its diverse distribution, only about 40,000 to 60,000 species of microalgae have been described. There are many species yet to be described including the extremophiles (Norton et al., 1996; Sastre and Posten, 2010)

Status of sea cucumber resources and impact of fishing ban on the livelihood of fishers in Gulf of Mannar and Palk Bay

The sea cucumbers constitute an important part of non-fish income source for thousands of fishers along Gulf of Mannar and Palk Bay of south east coast of India. The fishery which is more than thousand years old was introduced by the Chinese stationed at Ramanathapuram, for preparing a dried sea cucumber product Beche-de-mer. The sea cucumber fishery in Gulf of Mannar and Palk Bay was artisanal in nature and consisted of fishermen who were good divers, the processors who acted as middlemen and the exporters. The sea cucumbers were chiefly collected by skin diving to a depth of 1.5 to 6.0 m in the shallow seas using nonmechanised country crafts. They were also caught as by-catch in trawlers locally known as Thallu madi (an indigenous modified trawler operating on wind power in shallow waters), besides the Chanku madi and Attai madi which were operated in deeper coastal waters

Sea cucumber conservation in Palk Bay and Gulf of Mannar, India "An evaluation of the current conservation measures on sea cucumber stocks in Palk Bay and Gulf of Mannar of India"

Sea cucumber fishery and trade were one of the top non-finfish income streams for the coastal people of Palk Bay and Gulf of Mannar in the South East coast of India. As there was no regulation to control the fishery, there was a concern on decline in sea cucumber populations. In order to conserve the over-exploited stocks, the Ministry of Environment, Forestry and Climate Change, Government of India banned the fishery and trade of sea cucumbers by including them under Wild Life Protection Act 1972 since 2001. The enforcement of a blanket ban of sea cucumber fishing over the last 14 years might have helped in reviving their populations; at the same time, the ban would possibly had a social and economic impact on scores of people, who were dependent on the sea cucumber fishery. To understand the situation, the Bay of Bengal Large Marine Ecosystem (BOBLME) project approved a short term project to Central Marine Fisheries Research Institute (India). The project was intended to understand the sea cucumber stocks and implications of the ban on the livelihood of fishers in Palk Bay and Gulf of Mannar. The purpose of the project was also to suggest management options for conservation and sustainable use of sea cucumber resources

Phenotypic and genetic characterization of Dunaliella (Chlorophyta) from Indian salinas and their diversity

Background: The genus Dunaliella (Class – Chlorophyceae) is widely studied for its tolerance to extreme habitat conditions, physiological aspects and many biotechnological applications, such as a source of carotenoids and many other bioactive compounds. Biochemical and molecular characterization is very much essential to fully explore the properties and possibilities of the new isolates of Dunaliella. In India, hyper saline lakes and salt pans were reported to bloom with Dunaliella spp. However, except for the economically important D. salina, other species are rarely characterized taxonomically from India. Present study was conducted to describe Dunaliella strains from Indian salinas using a combined morphological, physiological and molecular approach with an aim to have a better understanding on the taxonomy and diversity of this genus from India. Results: Comparative phenotypic and genetic studies revealed high level of diversity within the Indian Dunaliella isolates. Species level identification using morphological characteristics clearly delineated two strains of D. salina with considerable β-carotene content (>20 pg/cell). The variation in 18S rRNA gene size, amplified with MA1-MA2 primers, ranged between ~1800 and ~2650 base pairs, and together with the phylogeny based on ITS gene sequence provided a pattern, forming five different groups within Indian Dunaliella isolates. Superficial congruency was observed between ITS and rbcL gene phylogenetic trees with consistent formation of major clades separating Indian isolates into two distinct clusters, one with D. salina and allied strains, and another one with D. viridis and allied strains. Further in both the trees, few isolates showed high level of genetic divergence than reported previously for Dunaliella spp. This indicates the scope of more numbers of clearly defined/unidentified species/subspecies within Indian Dunaliella isolates. Conclusion: Present work illustrates Indian Dunaliella strains phenotypically and genetically, and confirms the presence of not less than five different species (or sub-species) in Indian saline waters, including D. salina and D. viridis. The study emphasizes the need for a combined morphological, physiological and molecular approach in the taxonomic studies of Dunaliella

Halophytes of Chenopodiaceae and Aizoaceae from South-East Coast of India as Potential Sources of Essential Nutrients and Antioxidants

In this study, we assessed the antioxidant efficacy and nutritional value of the halophytic plants in order to find possible sources for future novel antioxidants in nutraceutical and pharmaceutical formulations. The lyophilized samples of the five tropical halophytes (Chenopodiaceae and Aizoaceae), namely, Salicornia brachiata, Arthrocnemum indicum, Suaeda maritima, Suaeda monoica, and Sesuvium portulacastrum from the southeast coast of India were analyzed for total digestible protein, amino acid and fatty acid composition using spectrophotometric, HPLC and GC methods, respectively. The aqueous and ethyl acetate extracts of these samples were studied for its free radical scavenging activity using DPPH. radical scavenging assay and total phenolic content (mg GAE/g) using Folin–Ciocalteu method. Protein content of S. brachiata (4.6 g/100g) and S. maritima (4.0 g/100g) were higher than that of others. A good ratio of essential/ non-essential (E/NE) amino acids in all species (>1.0) indicated them as sources of well balanced and high-quality proteins. High DHA (1.33%) and EPA (1.26%) in S. maritima resulted in having a higher n-3:n-6 ratio (0.24) than in other halophytes (0.09-0.16). The PUFA/ SFA ratio was found to be significantly higher in S. brachiata (1.16) due to high 18:2n-6 (16.9%) and 18:3n-6 (21.9%) (p < 0.05), suggesting its ability to thrive under stress conditions, which was supported by the high phenolic contents (557 mg GAE/g) and antioxidant activity against DPPH radical (IC50 0.90 mg/mL) of its EtOAc extract. The presence of high titer of amino acids, fatty acids, nutritional antioxidants (phenolics) and free radical quenching potential of these underutilized species indicate their potential towards human health applications

Socio-economic Impact of Sea cucumber Conservation in Palk Bay and Gulf of Mannar Region of Tamil Nadu

Sea cucumber is one of the important marine resources and its fishery is a source of income to coastal communities. It contributes to poverty alleviation for more than three million fishers globally. The indiscriminate exploitation for this lucrative trade would have resulted in overexploitation leading to endangering of the species in the wild. The blanket ban on collection and trade on sea cucumber in India was imposed during 2002 by listing this organism in Schedule I category of the Wildlife Protection Act of 1972. The present study aimed to analyze and understand the impacts of listing on the conservation of sea cucumber resources in the wild and on the livelihood of the fishers. The enforcement of ban has affected the livelihood of thousands of fishermen families involved in sea cucumber fishing. There was a loss in their regular income as they were not able to do other fishing activities due to lack of capacity for investment. The fishers opined that they want the ban to be lifted at least for a few commercially important species. They are agreeable to follow regulatory measures like size restriction on fishing of undersized sea cucumbers, exclusion of breeding stock from fishing, restraining from use of destructive gears, exclusive fishing ban period for stock replenishment, sea ranching and stock enhancement programmes for conservation of the resource through participatory co-management principles

Spatial variations in the population characteristics of sea cucumber resources in Gulf of Mannar and Palk Bay, south-east coast of India

The lack of data on population abundance, biomass and basic biological parameters of most of the sea cucumber species from Indian waters is a fundamental barrier to impose suitable management measures on these resources. A study was conducted to ascertain the sea cucumber population characteristics in two geographically distinct ecosystems (Gulf of Mannar and Palk Bay) along the south-east coast of India. The stock status of sea cucumber population was assessed both by trawl and dive surveys following standard methods on a random basis. Comparatively, a higher average density of total sea cucumbers was estimated in the Gulf of Mannar (3853±152.3 nos. ha-1) than in Palk Bay (2428.5±504.6 nos. ha-1). The species diversity, average length and weight of individual species were also higher in the Gulf of Mannar. The present study indicated significant variation in status and structure of sea cucumber resources in these two ecosystems. Hence the study warrants the emphasis of ecosystem-based management in formulating conservation measures of these resources in Indian waters

Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

Terrestrial net CH&lt;sub&gt;4&lt;/sub&gt; surface fluxes often represent the difference between much larger gross production and consumption fluxes and depend on multiple physical, biological, and chemical mechanisms that are poorly understood and represented in regional- and global-scale biogeochemical models. To characterize uncertainties, study feedbacks between CH&lt;sub&gt;4&lt;/sub&gt; fluxes and climate, and to guide future model development and experimentation, we developed and tested a new CH&lt;sub&gt;4&lt;/sub&gt; biogeochemistry model (CLM4Me) integrated in the land component (Community Land Model; CLM4) of the Community Earth System Model (CESM1). CLM4Me includes representations of CH&lt;sub&gt;4&lt;/sub&gt; production, oxidation, aerenchyma transport, ebullition, aqueous and gaseous diffusion, and fractional inundation. As with most global models, CLM4 lacks important features for predicting current and future CH&lt;sub&gt;4&lt;/sub&gt; fluxes, including: vertical representation of soil organic matter, accurate subgrid scale hydrology, realistic representation of inundated system vegetation, anaerobic decomposition, thermokarst dynamics, and aqueous chemistry. We compared the seasonality and magnitude of predicted CH&lt;sub&gt;4&lt;/sub&gt; emissions to observations from 18 sites and three global atmospheric inversions. Simulated net CH&lt;sub&gt;4&lt;/sub&gt; emissions using our baseline parameter set were 270, 160, 50, and 70 Tg CH&lt;sub&gt;4&lt;/sub&gt; yr&lt;sup&gt;−1&lt;/sup&gt; globally, in the tropics, in the temperate zone, and north of 45° N, respectively; these values are within the range of previous estimates. We then used the model to characterize the sensitivity of regional and global CH&lt;sub&gt;4&lt;/sub&gt; emission estimates to uncertainties in model parameterizations. Of the parameters we tested, the temperature sensitivity of CH&lt;sub&gt;4&lt;/sub&gt; production, oxidation parameters, and aerenchyma properties had the largest impacts on net CH&lt;sub&gt;4&lt;/sub&gt; emissions, up to a factor of 4 and 10 at the regional and gridcell scales, respectively. In spite of these uncertainties, we were able to demonstrate that emissions from dissolved CH&lt;sub&gt;4&lt;/sub&gt; in the transpiration stream are small (&lt;1 Tg CH&lt;sub&gt;4&lt;/sub&gt; yr&lt;sup&gt;−1&lt;/sup&gt;) and that uncertainty in CH&lt;sub&gt;4&lt;/sub&gt; emissions from anoxic microsite production is significant. In a 21st century scenario, we found that predicted declines in high-latitude inundation may limit increases in high-latitude CH&lt;sub&gt;4&lt;/sub&gt; emissions. Due to the high level of remaining uncertainty, we outline observations and experiments that would facilitate improvement of regional and global CH&lt;sub&gt;4&lt;/sub&gt; biogeochemical models

Present state of global wetland extent and wetland methane modelling: methodology of a model inter-comparison project (WETCHIMP)

The Wetland and Wetland CH4 Intercomparison of Models Project (WETCHIMP) was created to evaluate our present ability to simulate large-scale wetland characteristics and corresponding methane (CH4) emissions. A multi-model comparison is essential to evaluate the key uncertainties in the mechanisms and parameters leading to methane emissions. Ten modelling groups joined WETCHIMP to run eight global and two regional models with a common experimental protocol using the same climate and atmospheric carbon dioxide (CO2) forcing datasets. We reported the main conclusions from the intercomparison effort in a companion paper (Melton et al., 2013). Here we provide technical details for the six experiments, which included an equilibrium, a transient, and an optimized run plus three sensitivity experiments (temperature, precipitation, and atmospheric CO2 concentration). The diversity of approaches used by the models is summarized through a series of conceptual figures, and is used to evaluate the wide range of wetland extent and CH4 fluxes predicted by the models in the equilibrium run. We discuss relationships among the various approaches and patterns in consistencies of these model predictions. Within this group of models, there are three broad classes of methods used to estimate wetland extent: prescribed based on wetland distribution maps, prognostic relationships between hydrological states based on satellite observations, and explicit hydrological mass balances. A larger variety of approaches was used to estimate the net CH4 fluxes from wetland systems. Even though modelling of wetland extent and CH4 emissions has progressed significantly over recent decades, large uncertainties still exist when estimating CH4 emissions: there is little consensus on model structure or complexity due to knowledge gaps, different aims of the models, and the range of temporal and spatial resolutions of the models