Detection of possible thunderstorm formation inferred from weather element changes at ground level on a mountain slope

Authors and Affiliation: Vishnu R, Murali Das S, Sampath S and Mohan Kumar G, Centre for Earth Science Studies, Akkulam, Trivandrum, Kerala

Journal: Journal of Lightning Research, II, 12-24, 2010

Abstract: In India, Kerala state is known to have relatively high lightning incidence. The nature of spatial and temporal distribution of past incidents, type of thunderclouds which cause lightning, the topography, proximity to a mountain range 

and sea point to the possibility of the mountain weather aiding in Cb formation. For investigating the role of mountain weather in convective Cb formation a field station consisting of an automatic weather station and a lightning detector was established on the slope of the nearby Western Ghats mountain range. On thunderstorm days the mountain weather data show specific reduction in air temperature with synchronized increase in relative humidity along with a reduction in pressure of the order of 0.5 hPa between 10:00 h and 18:00 h. The variations in data are indicative of a strong updraft. The lightning detector showed thunderstorm activity, aligned with the direction of the mountain range, about an hour after detecting the changes in weather elements. Water vapour for thunderstorm formation seems to come from the nearby sea as indicated by the wind data. Data collected for three years show that existence of strong updrafts seem to be a characteristic of the mountain weather during thunderstorm months. Data from a coastal station located 40 km south west of the mountain station do not indicate updrafts either on the thunderstorm days or otherwise. As updrafts can lead to Cb formation monitoring weather elements as discussed here is useful for detecting thunderstorms at the developing stage itself.

Prevalence of autochthonous Vibrio cholera and role of abiotic environmental factors in their distribution along the Kerala- Karnataka Coast

Authors and Affiliation: V.S. Sudhanandh , S. Amaldev and K.N. Babu, Centre for Earth Science Studies, Akkulam, Trivandrum, Kerala

Journal: Research Journal of Microbiology, 5(11), 2010, 1083-1092

Abstract: Occurrence and distribution of Vibrio cholerae (VC) with respect to different abiotic environmental factors were studied for a period of three year from 2003-2005 and interpreted using Principal component analysis and Pearson correlation. Study reveals the serious dimensions of increase in VC population (2.67% in 2003, 5.33% in 2004 and 92% in 2005 in Mangalore) over the years. Among all stations, Kochi and Mangalore seems to be highly polluted. The PCA extracted four significant main components explains more than 75% of the variance. Of them the most contributing descriptors in the first PC (24.29%) were total nitrogen, silicate, temperature and V.cholerae. On the other hand V. cholerae showed significant positive correlation against temperature (0.01 levels) and also with total nitrogen and silicate (0.05 levels). Component plot showed that variables have tendency to accumulate into three distinct groups. V. cholerae and temperature belongs to one group and nutrients on the other group, which indicate that temperature and nutrients are the major factor governing the distribution of V. cholerae. The result of the study provides insight into the ecology of this aquatic species and is potentially important to the understanding of the epidemiology of cholerae on a global scale.

Late quaternary evolution of Ashtamudi-Sasthamkotta lake systems of Kerala, south west India

Authors and Affiliation: (a)K M Nair, (b)D Padmalal, (c)K P N Kumaran, (b)R Sreeja, (c)Ruta B Limaye, (b)Reji Srinivas, (a) Vakkom Moulavi Foundation Trust, Trivandrum, Kerala 695 037, India (b)Centre for Earth Science Studies, Akkulam, Trivandrum, Kerala 695 031, India (c)Palynology and Palaeoclimate Laboratory, Palaeobiology Group, Agarkar Research Institute, Pune 411 004, India

Journal: Journal of Asian Earth Sciences (2010), Volume: 37 (4) 361-372

Abstract: Sedimentological and palynological analysis of two borehole samples collected from the confluence of Kallada River with the Ashtamudi lake in the south west coast of India have been addressed while ascertaining the late quaternary evolution. Of the two borehole samples, the one collected from Pangod (903'N-7642'E) reveals a fining upward sequence with medium to coarse sand (3.05m) at base, organic carbon rich, silt and fine sand dominated sediments (2m) at the middle and yellowish brown, muddy sediments (3.2m) at the top. The middle layer embeds a suite of partly carbonized, sub-fossil logs of wet evergreen to semi-evergreen vegetation. The palynoflora of this layer reveals that the depositional site is within the tidal limit and deposition occurred under high precipitation and atmospheric humidity. The similarity in 14C dates of a wood at 5m bgl (749090yrs BP) and the embedding sediments (748080yrs BP) indicate quick burial of the riparian vegetation. The West Kallada borehole (930'N-7637'E) reveals Middle to Late Holocene sequence of clayey silt (6250110yrs BP-388080yrs BP) and sand resting unconformably over greyish white, clayey sand with pebbles and granules derived from laterite provenance. Palynological analysis shows that the Holocene sedimentation took place under marine/nearly marine environment and later changed to brackish water and finally to freshwater environment. Marine transgression ~6000yrs BP coupled with heavy rainfall in the hinterlands was responsible for faster sedimentation in the region. The heavy mineral contents, especially opaques, garnet and sillimanite in the sediment samples of the study area as well as the bathymetric configuration of the Ashtamudi, Sasthamkotta and Chelupola lakes reiterate the fact that these lakes have been evolved from an embayment consequent to incomplete/partial silting up during Early to Middle Holocene higher sea levels and also under high rainfall of the Holocene climatic optimum of around 10,000-7000yrs BP.

Changing pattern of species composition and species utilization in homegardens of Kerala, India

Authors and Affiliation: Chandrashekara UM and Baiju EC, Kerala Forest Research Institute Sub Centre, Chandakunnu P.O., Nilambur 679 342, Kerala, India

Journal: Tropical Ecology 51(2): 221-233, 2010

Abstract: Tropical homegardens are traditional agroforestry systems with complex structure and multiple functions. These multi-species production systems are regarded as the model systems for designing sustainable agroecosystems. However, with the advent of market economy, mixed species tropical homegardens are being transformed into single species dominant homegardens. The objective of this study was to analyze the impact of homegarden transformation on species diversity and also changing pattern of usage of species wealth by farmers in Kerala. The plant diversity index values ranged from 1.02 to 2.97 with significantly (P < 0.05) greater value in old mixed-species homegardens (OMSHG) followed by new mixedspecies homegardens (NMSHG), old single species dominant homegardens (OSSHG) and new single-species homegardens (NSSHG). About 65 % - 83 % of total number of naturally growing species in mixed species homegardens and 20 % - 30 % in single species dominant homegardens are managed. The ratio between actual usage of species and the potential uses of species in each homegarden was calculated. The value obtained for naturally growing species was significantly greater (P < 0.05) in the old homegardens than in new homegardens. We conclude that the knowledge base on the properties and potential uses of naturally growing species in homegardens is depleting due to transformation of homegardens into single species dominant systems.

Relationship between heavy mineral placer deposits and hinterland rocks of southern Kerala: A new approach for source-to-sink link from the chemistry

Authors and Affiliation: G.R. Ravindra Kumar & C. Sreejith, Centre for Earth Science Studies, Thuruvaikkal P.O., Thiruvananthapuram 695031, Kerala, India

Journal: Indian Journal of Geo-Marine Sciences, Vol. 39 (4), December 2010, pp. 562-571

Abstract: Beach sediments of the Kerala coast contain rich economically important heavy mineral deposits. Most previous studies have traced the source of heavy minerals to the Precambrian crystalline formations in the hinterland based on comparative mineral occurrences. No previous study has attempted to utilize petrological and geochemical characteristics and mineral chemistry of source rocks to effectively compare and determine sediment provenance. A clear knowledge on the composition of minerals from source and sink is important in precise recognition of source rock. Present study consists the geological, geomorphologic setting and mineralogical characteristics of hinterland rocks to trace their connection to placer deposits. It is recognized that garnet as the abundant heavy mineral in the placer sediments and in source rocks of different ages and petrogenetic affinity. Garnet composition varies between different source rock types due to its strong dependency on the bulk rock composition. In order to decipher the provenance we have compared major element composition of garnet in the source rocks and placer deposits. Compelling similarities in mineralogical and mineral chemical characteristics of garnets (Alm68Prp28Grs3Sps1) is noted between khondalites and placer sediments suggesting latter as major source rock for placer deposits of southern Kerala. The study demonstrates excellent potential of garnets in identifying placer mineral source.

Environmental Impact Assessment of sand mining from the small catchment river in the southwestern coast of India. Environmental Management

Authors and Affiliation: Sreedharan Sreebha and Damodaran Padmalal, Centre for Earth Science Studies, Thuruvaikkal P.O., Thiruvananthapuram 695031, Kerala, India

Journal: Environmental Management (2011), Vol. 47, pp.130-140.

Abstract: In the past few decades, the demand for construction grade sand is increasing in many parts of the world due to rapid economic development and subsequent growth of building activities. This, in many of the occasions, has resulted in indiscriminate mining of sand from in-stream and floodplain areas leading to severe damages to the river basin environment. The case is rather alarming in the small catchment rivers like those draining the southwestern coast of India due to limited sand resources in their alluvial reaches. Moreover, lack of adequate information on the environmental impact of river sand mining is a major lacuna challenging regulatory efforts in many developing countries. Therefore, a scientific assessment is a pre-requisite in formulating management strategies in the sand mining-hit areas. In this context, a study has been made as a case to address the environmental impact of sand mining from the in-stream and floodplain areas of three important rivers in the southwestern coast of India namely the Chalakudy, Periyar and Muvattupuzha rivers, whose lowlands host one of the fast developing urban-cum-industrial centre, the Kochi city. The study reveals that an amount of 11.527 million ty(-1) of sand (8.764 million ty(-1) of in-stream sand and 2.763 million ty(-1) of floodplain sand) is being mined from the midland and lowland reaches of these rivers for construction of buildings and other infrastructural facilities in Kochi city and its satellite townships. Environmental Impact Assessment (EIA) carried out as a part of this investigation shows that the activities associated with mining and processing of sands have not only affected the health of the river ecosystems but also degraded its overbank areas to a large extent. Considering the degree of degradation caused by sand mining from these rivers, no mining scenario may be opted in the deeper zones of the river channels. Also, a set of suggestions are made for the overall improvement of the rivers and its biophysical environment.

Evolution of the coastal wetland systems of SW India during the Holocene: Evidence from marine and terrestrial archives of Kollam coast, Kerala

Authors and Affiliation : D. Padmalal, K.P.N. Kumaran, K.M. Nair, B. Baijulal, Ruta B. Limaye, S. Vishnu Mohan, Centre for Earth Science Studies, Thuruvaikkal P.O., Thiruvananthapuram 695031, Kerala, India

Journal: Quaternary International, Volume 237, Issues 1-2, 15 May 2011, Pages 123-139

Abstract: Kerala coast in southwest India is endowed with an interlacing network of wetlands evolved during the Late Quaternary. The wetlands in the southern part of Kerala, especially around Kollam district, show antecedent characteristics and are incised on the Neogene sediments. These wetlands include 20.0–35.0 m thick deposits of Holocene sediments containing good archives of landform evolution and climate changes. Holocene sedimentation was initiated at about 8920 ± 110 BP and is represented mainly by sub-fossil wood/peat or carbonaceous clays. Subsequent deposition of brackish water to marine sediments occurred in the Middle Holocene. The proposed evolutionary model reveals that many wetland bodies including Sasthamkotta Lake, Chelupola Lake, Chittumalachira Lake and Kotta Lake were evolved from the proto-estuarine basins. The upper arms of the pre-Holocene Ashtamudi and Paravur estuaries were cut off due to progradation of alluvial sediments during the Holocene Climatic Optimum.

Characterization of novel alleles of toxin co-regulated pilus A gene (tcpA) from environmental isolates of Vibrio cholerae

Authors and Affiliation: Praveen Kumar, Anuja Thulaseedharan, Gautam Chowdhury, Thandavarayan Ramamurthy and Sabu Thomas

Journal: Current Microbiology, 62:758-763, (2011)

Abstract: Vibrio cholerae is causative agent of life threatening diarrheal disease, cholera. The toxin co-regulated pilus (TCP) is a critical colonization factor of V. cholerae and it also serves as receptor for CTXФ. In this study, we describe nucleotide sequence of four novel alleles of tcpA gene from toxigenic and non-toxigenic V. cholerae isolated from environmental sources. The phylogenetic analysis of tcpA revealed that it is related to tcpA of newly emerged O1 strain and unrelated to tcpA of wild type (classical and El Tor strains). All strains showed variant tcpA and also harbored intact Vibrio Pathogenicity Island (VPI). The expression of all variant alleles was demonstrated by RT-PCR.

Stratification and population structure of the genetic resources of ancient medicinal rice (Oryza sativa L.) landrace Njavara.

Authors and Affiliation: Sreejayan, Suresh Kumar, U, Varghese G, Jacob TM and Thomas G,
Regional Facility for DNA Fingerprinting, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695 014, Kerala, India

Journal: Genetic Resources and Crop Evolution (2011) 58:697–711

Abstract: Njavara (shashtika in Sanskrit), a rice (Oryza sativa L.) landrace described in ancient Sanskrit treatises of Ayurveda for its nutritive and medicinal properties, is traditionally used in Kerala for Ayurveda treatments. We characterized the genetic resources of Njavara using 24 morphological traits and 664 amplified fragment length polymorphic (AFLP) markers. Different multivariate methods revealed four morphologically distinct types (morphotypes) in the Njavara germplasm, which were highly differentiated (Qst[0.65) for several quantitative variables. Eight quantitative variables together with glume or bran color stably discriminated the four morphotypes. In accordance with ancient literature, most Njavara accessions exhibit a short maturity (\90 days). AFLP analysis supported the morphological grouping; however, it resolved morphotype I into three distinct clusters, revealing six genotypes under the four morphotypes identified. The genotypes were highly differentiated (Fst = 0.7276; Gst = 0.7202) and highly homozygous. Qst—Fst comparison revealed a possible role for natural selection in structuring quantitative variables among Njavara populations. Data suggest that the Njavara germplasm represents a composite of highly homozygous genetically isolated units. The distinctness of Njavara accessions in the AFLP dendrogram in relation to other traditional rice strains further demonstrates that the genotypes are nevertheless genetically cohesive and perpetuated with minimum genetic admixing. Stabilizing selection traditionally performed by farmers for short maturity coupled with autogamous breeding may have retained the genetic purity and governed the genetic structure of Njavara. The morphotypes identified were named long yellow, short yellow, intermediate yellow and short black, after culm length and glume color, which differ strikingly among the Njavara accessions. The present comprehensive description, the first of this kind in Njavara, yields vital insight into the genetic resources of this crop, which is relevant for designing methods for its effective utilization in different fields of research.

Hierarchical Analysis of Zooplankton Assemblages over Semidiel Pattern in the Lagoon of Kavaratti Atoll, Lakshadweep Archipelago, India

Authors and Affiliation: J. Jean Jose, P. Udayakumar, V.J. Ajimon, R. Shibu, K. Narendra Babu and R.S. Baiju, Chemical Sciences Division, Centre for Earth Science Studies, Thiruvananthapuram, Kerala

Journal: Current Research Journal of Biological Sciences, s 2(4):294-298, 2010

Abstract: A hierarchical analysis of data concerning the zooplankton assemblages over a semidiel pattern were presented in the inside waters of Kavaratti lagoon. Gastropod larvae dominated in all time intervals throughout the study. The dendrogram matrix clearly indicated the community interrelation ships expressed by this univalve molluscan group over semidiel pattern towards other groups of zooplanktons aggregated in the collections. Copepod varieties form a single separate cluster and showed its presence as an opportunistic invader to the lagoon ecosystem. In the lagoon the zooplankton assemblages and community structure seem to be clearly more balanced over the diel variation, which is clearly reflected in the cluster tree plotted.

A base line study of trace metals in a coral sedimentary environment, Lakshadweep Archepelago

Authors and Affiliation: Anu Gopinath, Nair S.M., Kumar N.C., Jayalakshmi K.V. and Padmalal D, Centre for Earth Science Studies, Thiruvananthapuram, Kerala

Journal: Environmental Earth Sciences, Vol.59; 1245-1266, 2010

Abstract: Surficial and core samples collected from the sedimentary microenvironments of Lakshadweep Archipelago were analysed for their trace metal contents. The synoptical relations in spatial distributions with respect to environmental conditions such as pH, organic carbon and sediment texture were inter-correlated. Some of the metals exhibited good correlations with Fe/Mn, which reflect their similarity in distribution rather than anthropogenic enrichment. Inter-relating the variations in metal-pH relationships with metal-organic carbon, in general, those which exhibited positive correlations with pH, displayed negative interactions with organic carbon content and vice versa. Comparatively, higher values of Fe in the mangrove area of one of the islands highlight the possibility of precipitation of Fe as iron sulphides, which are common in mangrove ecosystem. Based on the contamination factors for Pb, Zn and Cd, as well as the geo-accumulation index of Cd, it can be generalised that some of the islands remain polluted with respect to these elements. An evaluation based on pollution load index shows that none of the islands surveyed for this study posed a serious threat in trace metal pollution. Bray Curtis similarity index was computed to find out the similarity among metals/islands, using non-transformed data of metal concentrations. Group linkage clustering technique was used for drawing dendrograms to show the similarity among them.

Molecular taxonomy of marine mammals stranded along Kerala coast

Authors and Affiliation: George S., Meenakshi K and Bijukumar A, Chemical Biology Group, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695 014, India

Journal: Current Science, 100, (1), 117-120, 2011

ABSTRACT: Application of molecular tools for the identification of threatened marine mammals has gained importance in recent years. Though live and dead strandings of cetaceans are common along the Indian coasts, the specimensare often not properly identified due to the lack of local taxonomic expertise and poor quality of the specimens. Two marine mammals washed ashore in a putrefied condition at Edayar (08°25′N lat., 76°57′E long.), Thiruvananthapuram District, southwest coast of India, were identified by sequencing of 16S rRNA and COI genes. Sequence and phylogenetic similarity search done with all entries in the DNA sequence database, GenBank using BLAST identified the stranded mammals as Bryde’s whale (Balaenoptera edeni) and finless porpoise (Neophocaena phocaenoides). The present report is the second record of B. edeni from the southwest coast of India.

LRRK2 G2019S mutation does not contribute to Parkinson's disease in South India.

Authors and Affiliation: Vijayan B, Gopala S, Kishore A, Department of Neurology, Comprehensive Care Centre for Movement Disorders, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India.

Journal: Neurol India. 2011 Mar-Apr;59(2):157-60.

BACKGROUND: The frequency of leucine-rich repeat kinase 2 (LRRK2) G2019S mutation, the most common genetic cause of Parkinson's disease (PD), shows significant variation based on ethnicity. Earlier reports suggest a very low frequency or absence of this mutation in Asians.

OBJECTIVE: To analyze the frequency of LRRK2 G2019S mutation in sporadic and familial cases of PD and normal controls of common ethnicity from South India. PATIENTS AND METHODS: We used direct sequencing technique of all DNA samples in a clinic-based study of sporadic (n = 100) and familial PD patients (n = 86 index cases) and normal controls (n = 100) of common ethnicity from South India. RESULTS: None among the patients or controls had the G2019S mutation. CONCLUSION: The founding events that influenced a number of other populations/ethnicities had no impact on the genetic makeup of PD patients from South India. Our findings support the current view that G2019S-associated PD may be population-specific. This has implications in genetic testing for PD and selection of subjects for potential future gene-based therapeutic trials for G2019S carriers in such populations.

Functional characterization of the CC chemokine RANTES from Pekin duck ( Anas platyrhynchos)

Authors and Affiliation: Arathy DS, Nair S, Soman SS, Issac A, Sreekumar E.; Molecular Virology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB), Thycaud P.O., Thiruvananthapuram 695014, Kerala, India.

Journal: Dev Comp Immunol. 2011 Jan;35(1):142-50. Epub 2010 Sep 23.

Abstract: RANTES (Regulated upon Activation, Normal T-cell Expressed and Secreted) is a key pro-inflammatory cytokine that belongs to the CC-group of chemokines. The present study was carried out to functionally characterize the previously identified RANTES homologue in domestic duck (GenBank Accession No. AY641435). Recombinant duck RANTES was expressed in Escherichia coli-based and HEK293T cell-based systems. A tRNA supplementation strategy was required to express the protein in E. coli due to the presence of rare codons. In biological assays using HEK293T cell-expressed protein, RANTES was found to mediate chemotaxis of DT-40 chicken B cells and primary duck splenocytes at a concentration of 0.505μg/ml (0.6μM). Immunostaining of the migrated splenocytes using anti-duck CD4 and CD8 monoclonal antibodies and subsequent flow cytometric analysis showed enhanced chemotaxis of CD8+ cells. The recombinant RANTES exhibited in vitro antiviral activity by inhibiting infection of chicken embryo fibroblast cells with duck enteritis virus (DEV) at the same concentration. The effect could be neutralized by rabbit anti-duck RANTES polyclonal serum. The mechanism seems to be direct on viral particles as evidenced by the need for co-incubation of RANTES with DEV prior to the infection for antiviral activity, and also by the enhanced binding of DEV to E. coli expressed purified RANTES on ELISA-based assays. Our results show that the duck RANTES has overlapping biological properties with its mammalian orthologue, and also has possible functional cross-reactivity with chicken immune cells indicated by the chemotaxis of DT-40 cells.

Molecular evidences for the chemosensitizing efficacy of liposomal curcumin in paclitaxel chemotherapy in mouse models of cervical cancer

Authors and Affiliation: Sreekanth CN, Bava SV, Sreekumar E, Anto RJ.; Integrated Cancer Research Program, Division of Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India.

Journal: Oncogene. 2011 Feb 14

Abstract: The microtubule-targeting antineoplastic agent, paclitaxel, is highly efficacious against a wide spectrum of human cancers. However, dose-limiting toxicity and development of drug resistance limit its clinical application. Development of novel strategies that overcome chemoresistance and sensitize cancer cells to paclitaxel can enhance the therapeutic effect of this drug. We have previously shown that curcumin, a natural polyphenol, enhances paclitaxel-induced cytotoxicity in vitro through downregulation of nuclear factor (NF)-κB and Akt pathways. This study was undertaken to determine whether this synergism exists in vivo and to elucidate the underlying molecular mechanisms. Mouse cervical multistage squamous cell carcinoma model using 3-methylcholanthrene (3-MC) and a xenograft model of human cervical cancer in nonobese diabetic severe combined immunodeficient (NOD-SCID) mice using HeLa cells were used to evaluate the synergism. We observed that the combined treatment of curcumin and paclitaxel induced a synergestic reduction in the tumor incidence as well as tumor volume of animals compared with the individual treatments of paclitaxel or curcumin, although curcumin alone could not induce any significant effect at the concentration used. The results suggest that a suboptimal concentration of curcumin augments the antitumor action of paclitaxel by downregulating the activation and downstream signaling of antiapoptotic factors and survival signals such as NF-κB, Akt and mitogen-activated protein kinases that have significant roles in proliferation, survival, angiogenesis and metastasis. This study revealed for the first time that 3-MC-induced tumorigenesis in mice is associated with a strong constitutive activation of NF-κB activity. Furthermore, we also observed that pre-exposure of carcinoma cells isolated from 3-MC-induced tumors to curcumin potentiates paclitaxel-induced apoptosis. Overall, the findings of this preclinical study provide a strong rationale for the validation of this combination through clinical trials. As curcumin could effectively downregulate all these survival signals induced by paclitaxel, we suggest it as a potent chemosensitizer to improve the therapeutic index of paclitaxel.

Characterization of novel alleles of toxin co-regulated pilus A gene (tcpA) from environmental isolates of Vibrio cholera

Authors and Affiliation: Kumar P, Thulaseedharan A, Chowdhury G, Ramamurthy T, Thomas S.; Department of Molecular Microbiology, Cholera and Environmental Microbiology Laboratory, Rajiv Gandhi Centre for Biotechnology, Trivandrum, Kerala, India.

Journal: Curr Microbiol. 2011 Mar; 62(3):758-63

Abstract: Vibrio cholerae is causative agent of life threatening diarrheal disease, cholera. The toxin co-regulated pilus (TCP) is a critical colonization factor of V.cholerae and it also serves as receptor for CTXФ. In this study, we describe nucleotide sequence of four novel alleles of tcpA gene from toxigenic and non-toxigenic V. cholerae isolated from environmental sources. The phylogenetic analysis of tcpA revealed that it is related to tcpA of newly emerged O1 strain and unrelated to tcpA of wild type (classical and El Tor strains). All strains showed variant tcpA and also harbored intact Vibrio Pathogenicity Island (VPI). The expression of all variant alleles was demonstrated by RT-PCR.

Selectivity in Garratt-Braverman Cyclization: An Experimental and Computational Study

Journal: Organic Letters, ASAP, 13 (5), pp 888–891, 2011

Authors: Manasi Maji, Dibyendu Mallick, Sayantan Mondal, Anakuthil Anoop, Subhendu Sekhar Bag, Amit Basak and *Eluvathingal D. Jemmis

Institute : *Indian Institute of Science Education and Research Thiruvananthapuram

Abstract: Bispropargyl sulfones equipped with aromatic rings of dissimilar nature were synthesized. Under basic conditions, these sulfones isomerized to the bisallenic sulfones, creating a competitive scenario between two alternate Garratt−Braverman (GB) cyclization pathways. The observed product distribution ruled out the involvement of any ionic intermediate and supported the diradical mechanism with greater involvement of the electron-rich aromatic ring via the more nucleophilic radical. DFT-based calculations supported the diradical mechanism along with the observed selectivity.

Cobalt (II) complexes of terpyridine bases as photochemotherapeutic agents showing cellular uptake and photocytotoxicity in visible light

Journal: Dalton Trans., 40, 1233-1242, 2011

Authors: Sovan Roy, Subhendu Roy, Sounik Saha, Ritankar Majumdar, Rajan R. Dighe, Eluvathingal D. Jemmis*, Akhil R. Chakravarty

Institute: *Indian Institute of Science Education and Research Thiruvananthapuram

Abstract: Cobalt(II) complexes of terpyridine bases [Co(L)2](ClO4)2 (1–3), where L is 4′-phenyl-2,2′:6′,2′′-terpyridine (ph-tpy in 1), 4′-(9-anthracenyl)-2,2′:6′,2′′-terpyridine (an-tpy in 2) and 4′-(1- pyrenyl)-2,2′:6′,2′′-terpyridine (py-tpy in 3), are prepared and their photo-induced DNA and protein cleavage activity and photocytotoxic property in HeLa cells studied. The 1 : 2 electrolytic and three-electron paramagnetic complexes show a visible band near 550 nm in DMF–Tris-HCl buffer. The complexes 1–3 show emission spectral bands at 355, 421 and 454 nm, respectively, when excited at 287, 368 and 335 nm. The quantum yield values for 1–3 in DMF–H2O (2 : 1 v/v) are 0.025, 0.060 and 0.28, respectively. The complexes are redox active in DMF–0.1 M TBAP. The Co(III)–Co(II) and Co(II)–Co(I) couples appear as quasi-reversible cyclic voltammetric responses near 0.2 and −0.7 V vs. SCE, respectively. Complexes 2 and 3 are avid binders to calf thymus DNA giving Kb value of [similar]106 M−1. The complexes show chemical nuclease activity. Complexes 2 and 3 exhibit oxidative cleavage of pUC19 DNA in UV-A and visible light. The DNA photocleavage reaction of 3 at 365 nm shows formation of singlet oxygen and hydroxyl radical species, while only hydroxyl radical formation is evidenced in visible light. Complexes 2 and 3 show non-specific photo-induced bovine serum albumin protein cleavage activity at 365 nm. The an-tpy and py-tpy complexes exhibit significant photocytotoxicity in HeLa cervical cancer cells on exposure to visible light giving IC50 values of 24.2 and 7.6 μM, respectively. Live cell imaging study shows accumulation of the complexes in the cytosol of HeLa cancer cells.

Tuning photosensitized singlet oxygen generation efficiency of novel Aza-BODIPY dyes

• Authors: Nagappanpillai Adarsh, Rekha R. Avirah, and Danaboyina Ramaia; Photosciences and Photonics, Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, CSIR, Trivandrum -695 019, Kerala, India
• Journal: Organic Letters, 12 (24), pp 5720–5723, November 19, 2010
• Abstract: Novel aza-BODIPY derivatives substituted with heavy atoms such as bromine and iodine were synthesized, and their triplet and singlet oxygen generation efficiencies have been investigated. These derivatives showed absorption in the NIR region with high molar extinction coefficients. The dye substituted with four iodine atoms showed yields of ΦT = 0.78 and Φ(1O2) = 0.70, which are the highest values so far obtained for the aza-BODIPY derivatives.
  

Characterization of sn-2 alk-1'-enyl ethers of glycerol from rice bran oil

• Authors: Afinisha Deepam LS, Arumughan C; National Institute for Interdisciplinary Science and Technology, Kerala, India.
• Journal: Journal of Oleo Science, 59, (10) 521-526, 26th October 2010
• Abstract: Ether lipids have biological applications which would dissipated as an important constituent in cell membranes. These are mostly found in animal tissues and rare in plant origin. Alk-1'-enyl ethers are class of ether lipid forming aldehydes on cleavage of ether bonds. The present study enrolled the presence of aldehyde in unsaponifiable matter of rice bran oil (RBO) and hence the identification of source of aldehydes in RBO was conducted. With respect to the earlier reports the investigation turned to major lipid constituents such as triacylglycerols, diacylglycerols etc. Using the column chomatographic method lipid fractions are separated, recolumned, purified and analyzed by spectrochemical methods such as FT-IR, (1)HNMR, (13)CNMR, Mass spectrometry and confirmed the presence of ether lipids. The sn-2 position was confirmed by enzymatic hydrolysis using pancreatic lipase. Moreover the formation of aldehyde from these ether lipids was also confirmed by spectrometric methods.
  

Characterization of an extracellular alkaline serine protease from marine Engyodontium album BTMFS10

• Sreeja Chellappan, C. Jasmin, Soorej M. Basheer, Archana Kishore, K. K. Elyas, Sarita G. Bhat and M. Chandrasekaran
• Micribial Technology Laboratory (MTL), Department of Biotechnolgoy, Cochin University of Science and Technology, Cochin, Kerala 682022, India
• Published in Journal of Industrial Microbiology & Biotechnology, 26 November 2010
• Abstract
  

An alkaline protease from marine Engyodontium album was characterized for its physicochemical properties towards evaluation of its suitability for potential industrial applications. Molecular mass of the enzyme by matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) analysis was calculated as 28.6 kDa. Isoelectric focusing yielded pI of 3–4. Enzyme inhibition by phenylmethylsulfonyl fluoride (PMSF) and aprotinin confirmed the serine protease nature of the enzyme. K m, V max, and K cat of the enzyme were 4.727 × 10−2 mg/ml, 394.68 U, and 4.2175 × 10−2 s−1, respectively. Enzyme was noted to be active over a broad range of pH (6–12) and temperature (15–65°C), with maximum activity at pH 11 and 60°C. CaCl2 (1 mM), starch (1%), and sucrose (1%) imparted thermal stability at 65°C. Hg2+, Cu2+, Fe3+, Zn2+, Cd+, and Al3+ inhibited enzyme activity, while 1 mM Co2+ enhanced enzyme activity. Reducing agents enhanced enzyme activity at lower concentrations. The enzyme showed considerable storage stability, and retained its activity in the presence of hydrocarbons, natural oils, surfactants, and most of the organic solvents tested. Results indicate that the marine protease holds potential for use in the detergent industry and for varied applications.