Silicon Carbide Whisker-Mediated Embryogenic Callus Transformation of Cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) and Regeneration of Salt Tolerant Plants

A silicon carbide whisker-mediated gene transfer system with recovery of fertile and stable transformants was developed for cotton (Gossypium hirsutum L.) cv. Coker-312. Two-month-old hypocotyl-derived embryogenic/non-embryogenic calli at different days after subculture were treated with silicon carbide whiskers for 2 min in order to deliver pGreen0029 encoding GUS gene and pRG229 AVP1 gene, encoding Arabidopsis vacuolar pyrophosphatase, having neomycin phosphotransferaseII (nptII) genes as plant-selectable markers. Three crucial transformation parameters, i.e., callus type, days after subculture and selection marker concentration for transformation of cotton calli were evaluated for optimum efficiency of cotton embryogenic callus transformation giving upto 94% transformation efficiency. Within six weeks, emergence of kanamycin-resistant (km^r) callus colonies was noted on selection medium. GUS and Southern blot analysis showed expression of intact and multiple transgene copies in the transformed tissues. Kanamycin wiping of leaves from T₁, T₂, and T₃ progeny plants revealed that transgenes were inherited in a Mendelian fashion. Salt treatment of T₁ AVP1 transgenic cotton plants showed significant enhancement in salt tolerance as compared to control plants. Thus far, this is first viable physical procedure after particle bombardment available for cotton that successfully can be used to generate fertile cotton transformants.     

Plasticity in life features,parasitism and super-parasitism behavior of Bracon hebetor,an important natural enemy of Galleria mellonella and other lepidopteran host species

The wasp, Bracon hebetor Say, is an important potential biocontrol agent of a wide range of lepidopteran insect species. The current study was subjected to compare these ectoparasitoid fitness traits on different host species belonging to the order Lepidoptera. Moreover, we determine the population dynamic with different host densities, sex ratio patterns, super-parasitism, longevity, paralysis success, and reproductive potential under laboratory conditions. Our results revealed that oviposition increased with an increase in host density, while the adult emergence and egg hatching were decreased due to the super-parasitism on host larvae. A higher male and female-biased population were observed when virgin and mated females offered fresh hosts. Adults' longevity was recorded more in females than males when kept only with bee honey + royal jelly + host larvae. The mean duration of egg-adult development was recorded higher on Galleria mellonella and lowest on Busseola fusca. The parasitization rate, super-parasitism, and cumulative fecundity of mated and virgin female wasps with different host species were observed higher on specific host Galleria mellonella while it was lower on Phthorimaea operculella. Furthermore, the parasitoids having mating experience preferred fresh, while the parasitoids' lack of mating experiences preferred paralyzed host under olfactometer test. Besides, this research has produced novel facts on the biology of parasitic wasp, B. hebetor that may guide the advancement of sustainable biological control programs to control lepidopteran pests.     

Stress impact of liposomes loaded with ciprofloxacin on the expression level of MepA and NorB efflux pumps of methicillin-resistant Staphylococcus aureus

International Microbiology - One mechanism of ciprofloxacin resistance is attributed to chromosomal DNA-encoded efflux pumps such as the MepA and NorB proteins. The goal of this research is to find...     

Microbial transformation of delta 9(15)-africanene

Incubation of delta 9(15)-africanene with fungi Aspergillus niger and Rhizopus oryzae for 8 days yielded two oxidized derivatives, 10 alpha-hydroxy-delta 9(15)-africanene and 9 alpha,15-epoxyafricanane. The structure of the two products were assigned by interpretation of their spectral data.     

Toxic and Antifeedant Effects of Different Pesticidal Plant Extracts against Beet Armyworm (<i>Spodoptera exigua</i>)

The beet armyworm (BAW), Spodoptera exigua (Lepidoptera: Noctuidae) is a highly destructive pest of vegetables and field crops. Management of beet armyworm primarily relies on synthetic pesticides, which is threatening the beneficial community and environment. Most importantly, the BAW developed resistance to synthetic pesticides with making it difficult to manage. Therefore, alternative and environment-friendly pest management tactics are urgently required. The use of pesticidal plant extracts provides an effective way for a sustainable pest management program. To evaluate the use of pesticidal plant extracts against BAW, we selected six plant species (Lantana camara, Aloe vera, Azadirachta indica, Cymbopogon citratus, Nicotianatabacum, and Ocimum basilicum) for initial screening experiment. Four out of six plant species such as A. indica, N. tabacum, C. citratus and O. basilicum showed promising mortality of more than 50%. Therefore, we selected these four plant extracts for the subsequent experiments. Through contact bioassay, A. indica showed high mortality 66.63%, followed by the N. tabacum 53.33%, at 10% w/v concentration. Similarly, N. tabacum showed the highest mortality rate, 66% at 10% w/v concentration, followed by the A. indica 46% through feeding bioassay. Furthermore, the feeding deterrence assay showed that C. citratus had a high antifeedant index (−50) followed by A. indica (−39), and N. tabacum (−28). In living plant assay, the N. tabacum extract showed a low mean damage score 3.6 on living cotton plant followed by C. citratus 4.5 and A. indica 5.5. Hence, extracts of three plant species provided promising results against the BAW, which can minimize the use of synthetic chemicals, particularly for small landholding farmers. Further studies are also required to evaluate the effects of these plant extract against BAW on cotton plants under field conditions to optimize the further use.     

An investigation of the homology of guanylate kinase isozymes in mammals and further evidence for multiple GUK gene loci

Guanylate kinase in the red cells of 63 different mammalian species was studied by electrophoresis and multiple molecular forms of the enzyme were found in all species. Two species were investigated in more detail. Using molecular weight estimates as a criterion of homology, the fallow deer and the Chinese hamster were found to have isozymes that corresponded to isozyme e, f, and g of man. Variation in the guanylate kinase isozymes was detected in a small population of orangutans. Results suggested that isozymes a and b were monomeric and that they were the products of a gene locus, GUK1, different from the locus GUK3 which coded for isozymes e, f, and g. Products c and d of the presumptive GUK2 locus were not found in the orangutan.     

The effect of benzyl penicillin on the ultrastructure of Neisseria gonorrhoeae

Electron microscopy of Neisseria gonorrhoeae grown on solid medium with a subinhibitory concentration of penicillin suggested that the amount of penicillin reaching each pair of gonococci was different, as illustrated by the ultrastructural appearance of N, gonorrhoeae cells in the colony. This supports the view that the concentration of penicillin in different parts of the colony is not uniform, causing some cells to lyse while the others remain intact.