ABSTRACT
The present study reports molecular characterization of small heat shock protein gene in Indian isolates of Chaetomium globosum, C. perlucidum, C. reflexum, C. cochlioides and C. cupreum. Six isolates of C. globosum and other species showed a band of 630bp using specific primers. Amplified cDNA product of C. globosum (Cg 1) cloned and sequenced showed 603bp open reading frame encoding 200 amino-acids. The protein sequence had a molecular mass of 22 kDa and was therefore, named Hsp22. BlastX analysis revealed that the gene codes for a protein homologous to previously characterized Hsp22.4 gene from C. globosum (AAR36902.1, XP 001229241.1) and shared 95% identity in amino acid sequence. It also showed varying degree of similarities with small Hsp protein from Neurospora spp. (60%), Myceliophthora sp. (59%), Glomerella sp. (50%), Hypocrea sp. (52%), and Fusarium spp. (51%). This gene was further cloned into pET28a (+) and transformed E. coli BL21 cells were induced by IPTG, and the expressed protein of 30 kDa was analyzed by SDS-PAGE. The IPTG induced transformants displayed significantly greater resistance to NaCl and Na2CO3 stresses.
ABSTRACT
Comparative larvicidal efficacy of aqueous and organic solvent extracts from seeds, leaves and flowers of three desert plants viz. Calotropis procera (Aiton), Tephrosia purpurea (L.) Pers. and Prosopis juliflora (Sw.) DC. was evaluated against Anopheles stephensi (Liston), Aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say). For this purpose larvae of all the three mosquito species were reared in the laboratory and studies carried out on late 3rd or early 4th instars using standard WHO technique. Based on concentration mortality data 24 and 48 hr LC50 and LC90 values along with their 95% fiducial limits, regression equation, chi-square (c2)/ heterogeneity of the response were determined by log probit regression analysis. Experiments were carried out with different solvent extracts of seeds of C. procera which revealed that methanol (24 hr LC50: 127.2, 194.8, 361.0) and acetone (229.9, 368.1, 193.0 mg l-1) extracts were more effective with the three mosquito species, respectively. Petroleum ether extract was effective only on An. stephensi while aqueous extracts were not effective at all with any of the mosquito species (mortality <10-30%). Tests carried out with methanol extracts of fresh leaves (24 hr LC50: 89.2, 171.2, 369.7) and flowers (24 hr LC50: 94.7,617.3, 1384.0 mg l-1) of Calotropis showed that preparations from fresh parts were 2-3 times more effective as compared to the stored plant parts. Efficacy was less than 10-30% with both An. aegypti and Cx. quinquefasciatus while An. stephensi was still susceptible to extracts from both leaves and flowers even after two years of storage. The 24 hr LC50 values as observed for methanol extracts of seeds of T. purpurea and leaves of P. juliflora were 74.9, 63.2 and 47.0 and 96.2, 128.1 and 118.8 mg l-1 for the above three mosquito species, respectively. Experiments carried out up to 500 mg l-1 with leaves (T. purpurea) and seeds (P. juliflora) extracts show only up to 10-30% mortality indicating that active larvicidal principle may be present only in the seeds of Tephrosia and leaves of Prosopis. In general, anophelines were found more susceptible than the culicines to the plant derived derivatives. More studies are being carried out on some other desert plants found in this arid region. The study would be of great importance while formulating vector control strategy based on alternative plant based insecticides in this semi-arid region.
ABSTRACT
Larvicidal potential of the extracts from different parts viz. green and red fruits, seeds, fruit without seeds, leaves and roots of Withania somnifera in different solvents was evaluated against larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, the important disease vectors prevalent in the semi-arid region. Experiments were carried out on late 3rd or early 4th instar larvae of these mosquitoes using standard WHO technique. 24 and 48 hr LC 50 values along with their 95% confidence limits, regression equation, chi-square (c2)/ heterogeneity of the response have been determined by log probit regression analysis. The 24 hr LC50 values as observed for whole green fruits in water, methanol and petroleum ether were 350.9, 372.4, 576.9; 115.0, 197.1, 554.6; 154.9, 312.0, 1085.0 while corresponding values for red fruits were 473.5, 406.4, 445.2; 94.7, 94.5, 1013.0; 241.8, 535.0, 893.3 mg l-1 for An. stephensi, Ae. aegypti and Cx. quinquefasciatus respectively showing that methanol extracts were more effective against anophelines as compared to culicines when whole fruits were taken. The 24 hr LC50 values as observed for seeds in acetone, methanol and petroleum ether were 188.1, 777.5, 822.5; 245.5, 769.0, 1169.0; 140.3, 822.9, 778.4 and for fruit without seeds were 80.2, 97.6, 146.6; 88.4, 404.4, 1030.0; 30.0, 44.5, 54.2 mg l-1 for the above mosquito species respectively showing that extract of fruit without seeds were most effective in petroleum ether followed by acetone and methanol extracts. However, experiments conducted with methanol extracts of leaves and roots of this plant species did not show any appreciable larvicidal activity and a 20-40% mortality was observed up to 500 mg l-1 of the extracts. Overall larvae of anophelines were found more susceptible as compared to culicines to all the extracts tested. Petroleum ether extract of fruit without seeds was found most effective against all the mosquito species showing that active ingredient might be present in this part of the plant species. The study would be of great importance while planning vector control strategy based on alternative plant derived insecticides.