Keratinolytic potential of Bacillus licheniformis RG1: structural and biochemical mechanism of feather degradation

Keratinolytic Bacillus licheniformis RG1 was used to study the mechanism of keratinolysis. Scanning electron microscopy studies revealed that bacterial cells grew closely adhered to the barbules of feathers, completely degrading them within 24 h. Biochemical studies indicated that the Bacillus strain produced an extracellular protease, which had keratinolytic potential. The extracellular keratinolytic activity (425 U) was synergistically enhanced by the addition of intracellular disulfide reductases (1712 U). However, these enzymes alone (keratinase and disulfide reductase), without live bacterial cells, failed to degrade the feather. Complete feather degradation was obtained only when living bacterial cells were present, emphasizing that bacterial adhesion plays a key role during the degradation process. The bacterial cells probably provide a continuous supply of reductant to break disulfide bridges. In addition, sulfite detected in the extracellular broth during feather degradation indicated that sulfitolysis may also play a role in feather degradation by the bacterium.     

Non-destructive sampling of maternal DNA from the external shell of bird eggs

The use of non-destructive sampling methods to collect genetic material from wildlife allows researchers to minimize disturbance. Most avian studies employ capturing and handling of young and parents to draw blood for DNA analysis. In some cases adult female birds are difficult to catch, so maternal genotyping has required collection of contour feathers from nests, or destructive sampling of eggs. Many species do not leave contour feathers in the nest, and destructive sampling has been unreliable due to contamination with embryonic DNA. Alternative field sampling techniques for collection of maternal DNA from birds are therefore desirable. Here we demonstrate that avian maternal DNA can be isolated in a non-invasive and non-destructive way from the external surface of eggs. We used cotton swabs to collect maternal DNA from the external shells of herring gull (Larus argentatus) and Caspian tern (Sterna caspia) eggs. DNA was then amplified by the polymerase chain reaction (PCR) for microsatellite genotyping. We verified that the DNA samples were maternal by comparing microsatellite profiles to those obtained from adults and chicks from the same nests. In 100% of Caspian tern (n=16) and herring gull families (n=12), the egg swabs that amplified matched the maternal microsatellite genotype. In a screening of many nests of both species, we successfully amplified microsatellite markers from 101/115 (88%) egg swabs. Swabs from eggs with blood stains on the shell were more likely to amplify successfully than those from clean eggs. The advantages of this new method include increased parentage assignment/exclusion power, and increased availability of maternal DNA for genotyping of species that do not deposit contour feathers in nests.     

Correction to: Expression of the entomotoxic Cocculus hirsutus trypsin inhibitor (ChTI) gene in transgenic chickpea enhances its underlying resistance against the infestation of Helicoverpa armigera and Spodoptera litura

Plant Cell, Tissue and Organ Culture (PCTOC) - A correction to this paper has been published: https://doi.org/10.1007/s11240-021-02054-x     

Disruption of Mitochondrial Complexes in Cancer Stem Cells Through Nano-based Drug Delivery: A Promising Mitochondrial Medicine

Mitochondria are the fulcrum for regulating cellular metabolism as well as apoptosis. The multi-lamellar vesicles (MLVs) liposome targeted against mitochondria can be formulated to disrupt mitochondrial integrity to attain programmed cell death of cancer stem cells (CSCs). The gold nanoparticles (GNPs) and a steroid nucleus (cyclopentanoperhydrophenanthrene ring) are encapsulated within MLV liposome that targets specifically to the CD44 receptor of the CSCs. Entering cytosol, it would bind distinctively to the malate–aspartate shuttle through a specifically designed ligand. Liposome fuses with the mito-membrane after associating with shuttle, thereby releasing both the components. The steroid disrupts mito-membrane’s integrity facilitating release of cytochrome c. Thus, GNPs enter into the mitosol and interact with the mitochondrial complexes to cease cellular respiration. Since the solid nano-based pharmaceutics has shown a lot of promises as a potent anticancer therapy, the role of MLV liposome can be proved to be a better weapon to terminate malignancy.     

Analysis of microtubule polymerization in vitro and during the cell cycle in Xenopus egg extracts

Microtubules are dynamic polymers that participate in multiple cellular processes such as vesicular transport and cell division. Microtubule dynamics alter dramatically during the cell cycle. An excellent system to study microtubule dynamics is Xenopus egg extracts since it is a system that is open to manipulation. The extracts can be cycled between mitosis and interphase allowing the study of microtubules in these phases as well as during cell cycle transitions. Here, we provide simple assays to study microtubules in extracts and in vitro using purified components. Protocols are provided for the purification of frog tubulin, microtubule pelleting from extracts and in vitro, assembly of microtubule structures in extracts, and isolation of microtubule-associated proteins from extract. These methods can be used to analyze the effect of a protein of interest on the microtubule cytoskeleton.     

Comprehensive analysis of class I and class II HLA antigens and chronic hepatitis B virus infection

Following an acute hepatitis B virus (HBV) infection, clearance or persistence is determined in part by the vigor and breadth of the host immune response. Since the human leukocyte antigen system (HLA) is an integral component of the immune response, we hypothesized that the highly polymorphic HLA genes are key determinants of viral clearance. HLA class I and II genes were molecularly typed in 194 Caucasian individuals with viral persistence and 342 matched controls who had cleared the virus. A single class I allele, A*0301 (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.30 to 0.72; P = 0.0005) was associated with viral clearance. The class II allele DRB1*1302 was also associated with clearance (OR, 0.42; 95% CI, 0.19 to 0.93; P = 0.03), but its significance decreased in a multivariate model that included other alleles associated with disease outcome as covariates. B*08 was associated with viral persistence both independently (OR, 1.59; 95% CI, 1.04 to 2.43; P = 0.03) and as part of the conserved Caucasian haplotype A*01-B*08-DRB1*03. The B*44-Cw*1601 (OR, 2.23; 95% CI, 1.13 to 4.42; P = 0.02) and B*44-Cw*0501 (OR, 1.99; 95% CI, 1.22 to 3.24; P = 0.006) haplotypes were also associated with viral persistence. Interestingly, both the B*08 haplotype and DR7, which forms a haplotype with B*44-Cw*1601, have been associated with nonresponse to the HBV vaccine. The associations with class I alleles are consistent with a previously implicated role for CD8-mediated cytolytic-T-cell response in determining the outcome of an acute HBV infection.     

Stability of diacylglycerol acyltransferase in dehydrated bovine muscle tissue

Meaningful estimates of diacylglycerol acyltransferase (EC 2.3.1.20) activity in different tissue samples require effective, unbiased methods of sample storage. Samples of the pars costalis diaphragmatis muscle (skirt muscle of the diaphragm) were obtained from 18- to 20-month-old cattle and assayed for microsomal protein content and diacylglycerol acyltransferase activity after having been stored under various conditions as dissected tissue or microsomes prepared from dissected tissue. There was relative enrichment of diacylglycerol acyltransferase specific activity (p<0.05) when samples prepared from the pars costalis diaphragmatis muscle were dehydrated and stored for 2 weeks, as compared to the control condition (in which the microsome fraction was prepared from fresh pars costalis diaphragmatis muscle and assayed immediately). The results suggested that dehydration was an effective method of storage for bovine muscle samples destined for estimation of the microsomal diacylglycerol acyltransferase activity. The dehydration approach for preparing samples for analysis of diacylglycerol acyltransferase activity might also prove useful to investigators who are interested in obtaining reliable estimates of the activity of other enzymes in tissue samples.     

Determinants of fruit and seed set in Pavonia dasypetala (Malvaceae)

Summary Measurements of foliage quality, physiological, and phenological condition of sample trees were used as independent variables in multiple correlation analyses to determine their effect on female and male spruce budworm larval dry weights. Female budworm from trees high in foliar concentrations of beta-pinene, myrcene and total nitrogen weighed less than those from trees lacking these characteristics. Male budworm from trees high in foliar concentrations of alpha-pinene, myrcene, terpinolene, citronellyl acetate, and bornyl acetate weighted less than those from trees lacking these characteristics. Additionally, relatively vigorous and productive trees tended to be less susceptible (as evidenced by reduced larval weight) to budworm of either sex.