Ecological variations in adult life table attributes of Aedes aegypti (L.) from the desert and coastal regions of India.

The ecological variation in biological and adult life-table attributes of two populations of Aedes aegypti (Diptera: Culicidae) from the desert (Jodhpur) and coastal (Kolkata) regions of India are assessed to understand the reproductive and survival strategies. The results showed that females lived longer than males in both strains. The desert strain was more r-strategist because of its higher intrinsic rate of increase (rm  = 0.23), finite rate of increase (λ = 1.25), lower life expectancy of males (7.9 days) and females (14.4 days), mean generation time (T = 19.2 days) and doubling time (DT = 3.0 days). However, there was no difference in net reproductive rate (R0 ) between the desert and coastal strains. The coastal strain showed a longer female life expectancy (22.0 days) than the desert strain (14.4 days). However, the fecundity (eggs/female/day) was lower in the coastal strain (11.4) than in the desert strain (15.1). Conclusively, the desert (Jodhpur) strain is adapted to a better r-strategy than the coastal (Kolkata) strain of Ae. aegypti, which might be helpful to flourish in harsh environmental conditions. This study may provide accurate predictions of Ae. aegypti population dynamics for vector management.

Structural-genetic insight and optimization of protease production from a novel strain of Aeromonas veronii CMF, a gut isolate of Chrysomya megacephala.

Structural-genetic characterization of protease producing genes and enzymes from microbial sources are seldom appreciated despite having its substantial utilization in protein engineering or genetic manipulation for biotechnological applications. Aeromonas veronii CMF, a mesophilic bacterium isolated from the gut of Chrysomya megacephala, was found to exhibited significant level of protease activity. For the revelation of genetic potential in relation to protease production, whole genome of this organism was sequenced and analysed while structure-function of different protease enzyme was predicated using various in silico analysis. The 4.5 mb CMF genome was found to encompass various types of protease and mostly they are neutral in nature. Enzyme production was highest in an optimum pH and temperature of 6.0 (32.09 ± 1.015 U/ml) and 35ºC (41.65 ± 1.152 U/ml), respectively. Other culture parameters for optimum production of protease were determined to be inoculum size (1%), incubation period (72 h), shaking condition (125 rpm), carbon and nitrogen source [2% lactose (92.21 ± 3.16 U/ml) and 0.5% urea (163.62 ± 4.31 U/ml), respectively] and effect of surfactants [0.02 mg/ml Tween 80 (174.72 ± 4.48 U/ml)]. Furthermore, A. veronii CMF exhibited significant enzyme production like serine protease (15.22 ± 0.563 U/ml), aspartate protease (33.16 ± 0.762 U/ml) and collagenase (17.26 ± 0.626 U/ml). Genomic information and results of physio-biochemical assays indicate its cost-effective potential use in different enzyme-industry.

Prevalence of mouthpart sensilla and protease producing symbiotic gut bacteria in the forensic fly Chrysomya megacephala (Fabricius, 1794): Insight from foraging to digestion.

The blow fly, Chrysomya megacephala (Fabricius, 1794) is a globally prevalent forensically important species that helps to estimate accurate postmortem interval since the death. This fly occasionally causes cutaneous myiasis and transmits several pathogenic bacteria. To understand their ability of corpse detection and digestion of protein-rich meal, the present study describes the mouthpart sensilla and assessment of protease producing symbiotic gut bacteria. Scanning electron microscopy (SEM) showed the prevalence of trichoid sensilla (Tr), basiconic sensilla (Ba) and microtrichia (Mr) on labellar lobes, haustellum and maxillary palps of mouthparts. Bacterial particles of both rod (small and large) and spherical shaped were detected in the gut of C. megacephala using SEM. The bacterial density was higher on the foregut and midgut in comparison to the hindgut. From 72 bacterial isolates, 10 isolates from the foregut region showed considerable protease-producing efficacy ranging between 3.98 - 6.83 GHR and 9.73 - 34.68 U/ml protease. Among these, the most promising protease-producing bacterial isolate showed 16S rDNA sequence similarity (99.85%) with Chryseobacterium artocarpi DNA. This bacterium was the first report from flies. The findings of the study might help in better understanding of the role of sensilla in host perception and foregut symbiotic bacterial association in protein digestion in C. megacephala.

Life table, survival and fecundity parameters of Aedes albopictus (Diptera: Culicidae) strains from desert and coastal regions of India.

The Asian tiger mosquito, Aedes albopictus (Skuse, 1895) is the anthropophilic and day-biter mosquito, residing in peridomestic habitats and is responsible for vector-borne diseases, i.e., chikungunya and dengue. The knowledge of mosquito life demographics is very important to provide a foundation for a successful vector control program. In the present study, a comparative adult life table, survival, and fecundity parameters were evaluated on desert (Jodhpur, Rajasthan) and coastal (Kolkata, West Bengal) strains of Aedes albopictus (Diptera: Culicidae) from India under the standard laboratory conditions. The results showed significant differences between these strains for the life expectancy of males, fecundity (total eggs/cohort and eggs/female life span), oviposition days, intrinsic rate of increase (rm), finite rate of increase (λ), and doubling time (DT). Female mosquitoes lived longer than the males in both strains. Significant differences were observed in the net reproductive rate (R0) between Kolkata and Jodhpur strains. The coastal (Kolkata) strain showed a longer male life expectancy (5.6 days) than the desert strain (4.0 days). However, the fecundity (eggs/female lifespan) was higher in Kolkata (360.2) than the Jodhpur strain (229.7). The Kolkata strain showed higher R0, rm, λ, and the lower T, DT than the Jodhpur strain. Conclusively, the results indicate that the coastal strain of Ae. albopictus is more r-strategist than the desert strain. This study may help in the precise prediction of Ae. albopictus population dynamics surviving in these geographical areas for vector management.