Sundaram Janarthanan

Screening of selected marine algae from the coastal Tamil Nadu, South India for antibacterial activity

Objective To screen the antibacterial efficacy of various solvent extracts of marine algae such as Sargassum wightii (S. wightii), Chaetomorpha linum (C. linum) and Padina gymnospora (P. gymnospora) against some selected gram-positive and gram-negative human pathogenic bacteria.

A new variant of antimetabolic protein, arcelin from an Indian bean, Lablab purpureus (Linn.) and its effect on the stored product pest, Callosobruchus maculatus.

The anti-metabolic or insecticidal gene, arcelin (Arl) was isolated, cloned and sequenced using sequence specific degenerate primers from the seeds of Lablab purpureus collected from the Western Ghats, Tamil Nadu, India. The L. purpureus arcelin nucleotide sequence was homologous to Arl-3 and Arl-4 alleles from Phaseolus spp. The protein it encodes has 70% amino acid identity with the amino acid sequences of Arl-3I, Arl-3III, Arl-4 precursor, Arl-4 and Arl-4I. The partially purified arcelin from the seeds of L. purpureus using an artificial diet confirmed the complete retardation of development of the stored product pest Callosobruchus maculatus at 0.2% w/w arcelin-incorporated artificial seeds.

Aquatic insect conservation: a molecular genetic approach

Ecosystem diversity, species richness and genetic diversity are the three major facets of biodiversity which deserve equal attention for conservation. However, genetic diversity is significant in identification of unique populations for conservation purpose. Aspects of DNA barcoding, loss of genetic diversity in cryptic species and examples of molecular phylogenetic and molecular phylogeographic studies on aquatic insects of headwaters from major biogeographic realms are briefly reviewed in the light of prioritization of taxa and habitats for conservation. Special emphasis is laid on identification of evolutionary significant units for effective conservation in the context of global climate change. Current methodologies for identifying potential loss of intraspecific genetic diversity are also highlighted with suggestions on future research priorities.

Phagodeterrence and insecticidal activity of Hyptis suaveolens (Poit.) against four important lepidopteran pests

This study was carried out to evaluate the antifeedant and larvicidal activities of Hyptis suaveolens Poit. (Lamiaceae) leaves crude extracts and their fractions against four lepidopteran pests namely Helicoverpa armigera (Hbn.), Spodoptera litura (Fab.), Earias vittella (Fab.) and Leucinodes orbonalis (G.). Hexane, chloroform and ethyl acetate extracts were tested by leaf disc and fruit disc no-choice methods at 1% and 1,000 ppm concentrations for crude and fractions, respectively. Ethyl acetate extract of H. suaveolens exhibited the maximum antifeedant and insecticidal activity at 1% concentration against all the tested insects. It was subjected to fractionation using silica column chromatography with different combinations of hexane and ethyl acetate used as mobile phase. Among the 15 fractions obtained, fraction 2 showed the maximum antifeedant and insecticidal activity against all tested insects at 1000 ppm concentration. Preliminary phytochemical analysis of fraction 2 showed the presence of terpenoids and alkaloids. H. suaveolens could be considered as a safe and eco-friendly insecticide for lepidopteron pest management.

A new species of the Choroterpes Eaton, 1881 subgenus Monophyllus Kluge, 2012 and a new record of the subgenus Choroterpes, s.s. (Ephemeroptera: Leptophlebiidae) from southern Western Ghats, India.

A new species of Choroterpes (Monophyllus) is described based on larvae collected from rivers of Karnataka part of the Western Ghats. Choroterpes (Monophyllus) nandini n. sp. can be distinguished from the only other species viz., C. (Monophyllus) monophyllus by the following combination of characters: (i) median emargination of labrum moderately deep, without denticles; (ii) gills 2-7 without tracheation and (iii) abdominal segment 6 and 7 without colour pattern. Choroterpes (Choroterpes) petersi Tong and Dudgeon 2003 is newly recorded based on larval collections from the eastern and western regions of southern Western Ghats.

Report on the occurrence of synanthropic derived form of Chrysomya megacephala (Diptera: Calliphoridae) from Royapuram fishing harbour, Chennai, Tamil Nadu, India

Abstract The occurrence of dipteran fly, Chrysomya megacephala (Fabricius, 1794) is reported for the first time from Royapuram fishing harbour (Chennai), Tamil Nadu, South East India. The fully grown third instar larvae of Chrysomya megacephala were collected from decaying fishes near Royapuram fishing harbour. This site is found to be the regular breeding site for Chrysomya megacephala. Larvae were reared under laboratory condition and freshly emerged adult flies from pupae were collected and identified by morphological features and molecular tools. Molecular identification through generation of DNA barcoding using mitochondrial COI gene of Chrysomya megacephala is appended.

DNA barcoding of mayflies (Insecta: Ephemeroptera) from South India

Abstract In this study, DNA barcodes were generated for 40 species belonging to 32 genera under 10 families of Ephemeroptera from South India. Nucleotide sequence divergences were calculated using the Kimura two-parameter distance model and a neighbour-joining analysis was performed to provide a graphic display of the patterns of divergence among the species. This study demonstrates that COI barcoding is effective in discriminating among the mayfly species of South India, and provides a reference library for their future molecular identification.

A new record of Potamanthellus caenoides Ulmer 1939 (Ephemeroptera: Neoephemereidae) from the southern Western Ghats of India.

Abstract Background As part of ongoing exploration of the mayflies of hill streams of the southern Western Ghats of India, we establish a new record of mayfly. New information Potamanthellus caenoides Ulmer 1939 is newly recorded based on larval collection from the upstream of Silent Valley National Park of the southern Western Ghats. Brief ecological notes are appended.