Mani Kannan

Vitellogenin from the Silkworm, Bombyx mori: An Effective Anti-Bacterial Agent

Silkworm, Bombyx mori, vitellogenin (Vg) was isolated from perivisceral fat body of day 3 of pupa. Both Vg subunits were co-purified as verified by mass spectrometry and immunoblot. Purified Vg responded to specific tests for major posttranslational modifications on native gels indicating its nature as lipo-glyco-phosphoprotein. The Vg fraction had strong antibacterial activity against Gram negative bacterium Escherichia coli and Gram positive bacterium Bacillus subtilis. Microscopic images showed binding of Vg to bacterial cells and their destruction. When infected silkworm larvae were treated with purified Vg they survived the full life cycle in contrast to untreated animals. This result showed that Vg has the ability to inhibit the proliferation of bacteria in the silkworm fluid system without disturbing the regular metabolism of the host.

Simulium (Gomphostilbia) (Diptera: Simuliidae) from Southern Western Ghats, India: Two new species and DNA barcoding

Two new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) are described on the basis of reared adult, pupal and larval specimens collected from Southern Western Ghats India. The morphological data of two new species S. (Gomphostilbia) panagudiense sp. n. and S. (Gomphostilbia) kottoorense sp. n. are assigned to the batoense species group in the subgenus Gomphostilbia. S. (Gomphostilbia) panagudiense sp.n. is characterized in the female by having the scutum without longitudinal vitta and arms of the genital fork wide basally and in the pupa by the stalk of ventral pair medium-long. S. (Gomphostilbia) kottoorense sp.n. is characterized by the arm of genital fork tapered near apex in the female and style in medial view 0.63 times as long as coxite in the male. Phylogeny of members in the genus Simulium was reconstructed based on DNA barcoding gene (cytochrome oxidase c subunit I). Tree analysis using new technology and maximum likelihood analyses are congruent with evidence of two new species in the subgenus Gomphostilbia and separated from other species.

Computational studies on molecular interactions of 6-thioguanosine analogs with anthrax toxin receptor 1

Dormant endospores of Bacillus anthracis are the causative agent of anthrax, which is an acute disease for both human and animals. Anthrax has been practised as biological weapon because of two attributes: i) short duration of spore germination, and ii) lethal toxaemia of the vegetative stage. Pathogenesis is caused by the activity of edema toxin and lethal toxin. Protective antigen (PA), is an essential component of both complexes, binds to Anthrax Toxin Receptor (ATR) and mediates the lethality in mammals. The combination of vaccine and antibiotics are preferred to be effective treatment for destruction of the vegetative cell wall but could not be a successive destructor for endospores. So the present study is intended to identify the small molecules as a potential inhibitor for ATR1. 3D structure of Anthrax Toxin Receptor 1 (ATR1) was built by using the crystal structure of Anthrax Toxin Receptor 2 (ATR2) from Homo sapiens as template. Molecular docking of 6-thiogunaosine (6-TG) analogs was performed on the ATR1 model and effective inhibitor was selected based on the docking results. The docking results showed that the three residues in the ATR1 binding pocket (Phe162, Asp160, and Phe22) were essential for making hydrogen bond with the 2-(2-bromo-6-chloro-4H-purin-9(5H)-yl)- 5-(hydroxymethyl) tetrahydrofuran-3,4-diol (C11H13N3O5). The data presented here strongly indicate that the interactions of these four residues are necessary for a stronger binding of the ATR1 with C11H13N3O5. Also, the study proposed C11H13N3O5 as an effective inhibitor by the comparison of docking energy.Graphical abstract

Proteomics analysis of crude squid ink isolated from Sepia esculenta for their antimicrobial, antibiofilm and cytotoxic properties

The present study deals with the proteomics analysis of crude squid ink isolated from Sepia esculenta for their antibacterial, antifungal, antibiofilm and cytotoxic properties. To achieve this, SDS-PAGE was used to separate proteins as bands, In-gel trypsin digested and analyzed by MALDI-TOF mass spectrometry. A total of 4 bands were identified by MASCOT search analysis namely astacin-like squid metalloprotease type I (ASMT-I), 70 kDa neurofilament protein (NP), uncharacterized protein LOC106181966 isoform X1 (UP-Iso-X1) and Ommochrome-binding protein (Oc-BP). Further, the obtained crude squid proteins were subjected to antimicrobial and antibiofilm activities against pathogenic bacterial and fungal strains respectively. Further, MTT assay was also carried out to deliberately explain the cytotoxic ability of crude squid ink protein against MCF-7 breast cancer cell lines. The results from the study revealed that, the proteins are shown to be toxic against pathogenic strains and breast cancer cell lines in a dose-dependent manner. More importantly, the proteins are well enough to eradicate biofilms substantiated by light and confocal laser scanning microscopic observations. Altogether, the crude squid ink proteins hampered the growth of breast cancer cells with an IC50 value of 65.3 ± 0.46 μg mL-1. In conclusion, it is believed that the proteins from crude squid ink will provide new insights in hampering bacterial biofilms and cancer in near future.

A new species of Simulium ( Gomphostilbia ) (Diptera: Simuliidae) from South India, with keys to Indian members of the subgenus Gomphostilbia

A new black fly species, Simulium (Gomphostilbia) cauveryense sp. n., is described based on adult female, adult male, pupal and larval specimens collected from Kushalanagar, Karnataka, South India. This new species is placed in the decuplum subgroup of the batoense species-group within the subgenus Gomphostilbia. Keys to the species of the subgenus Gomphostilbia reported from India are provided for females, males, pupae and mature larvae.

A new species of Prosopistoma Latreille, 1833 (Ephemeroptera: Prosopistomatidae) from South India.

A new species of Prosopistoma (Ephemeroptera: Prosopistomatidae) is described on the basis of mature nymphs from Coorg, Karnataka, South India. Prosopistoma coorgum, new species can be readily distinguished from the other members of Prosopistoma by the following combination of characters: inner margin of outer canine near apex with 2-3 short spines, the length ratio of maxillary palp segments (3.3:4.8:1), ventral margin of fore tibia with 6-8 pectinate setae, and gill II leaf-like and cleft.

Spatio-temporal dynamics of mosquitoes in stream pools of a biosphere reserve of Southern Western Ghats, India.

The spatial and temporal dynamics of mosquitoes in stream pools were examined in a biosphere reserve of the Southern Western Ghats, India. The immature mosquitoes in stream pools were collected from stream substrates of bedrock pool, boulder cavity and sand puddle. The collected larvae and pupae were reared and identified. In total, 16 species from four genera of mosquitoes were collected. The mosquito species from Culex and Anopheles were predominantly occurred. The bedrock pool had the highest diversity and abundance of mosquitoes. The statistical analyses showed that the substrate specificity and the seasons were positively related to the distribution of mosquitoes rather than spatial pattern. This study described the spatial and temporal pattern of mosquitoes in stream pools of the Southern Western Ghats. This information would be helpful to National Vector borne disease control program for surveillance and control.