Metabolic Reconfiguration in C. elegans Suggests a Pathway for Widespread Sterol Auxotrophy in the Animal Kingdom

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Comparative growth,cross stress resistance,transcriptomics of Streptococcus pyogenes cultured under low shear modeled microgravity and normal gravity

Streptococcus pyogenes is commonly found on pharynx, mouth and rarely on skin, lower gastrointestinal tract. It is a potential pathogen causing tonsillitis, pneumonia, endocarditis. The present study was undertaken to study the effects of low shear modeled microgravity on growth, morphology, antibiotic resistance, cross-stress resistance to various stresses and alteration in gene expression of S. pyogenes. The growth analysis performed using UV–Visible spectroscopy indicated decrease in growth of S. pyogenes under low shear modeled microgravity. Morphological analysis by Bio-transmission electron microscopy (TEM), Bio-scanning electron microscopy (SEM) did not reveal much difference between normal and low shear modeled microgravity grown S. pyogenes. The sensitivity of S. pyogenes to antibiotics ampicillin, penicillin, streptomycin, kanamycin, hygromycin, rifampicin indicates that the bacterium is resistant to hygromycin. Further S. pyogenes cultured under low shear modeled microgravity was found to be more sensitive to ampicillin and rifampicin as compared with normal gravity grown S. pyogenes. The bacteria were tested for the acid, osmotic, temperature and oxidative cross stress resistances. The gene expression of S. pyogenes under low shear modeled microgravity analyzed by microarray revealed upregulation of 26 genes and down regulation of 22 genes by a fold change of 1.5.     

A linkage group on pig chromosome 4 comprising the loci for blood group L, GBA, ATP1B1 and three microsatellites

Restriction fragment length polymorphisms (RFLPs) were described for the porcine loci for β-glucosidase (GBA) and the β-polypeptide 1 of the Na⁺, K⁺-transporting ATPase (ATP1B1). Linkage analyses using a three-generation pedigree provided evidence for the assignment of ATP1B1, GBA and two microsatellite loci (S0001 and S0067) to a previously described linkage group comprising the loci for blood group L (EAL) and an anonymous microsatellite (S0097). The linear order of the six markers was determined with confidence by multipoint analyses and the length of the linkage group was estimated at 88 CM. This linkage group was assigned to pig chromosome 4 on the basis of a previous physical localization of the ATP1B1 gene. In situ hybridization data for S0001 presented in this study were consistent with a localization on chromosome 4 and suggested a regional localization to 4pl2-pl3. The present study reveals conflicting data concerning the genetic localization of the K88 loci controlling the expression of the receptors for the E. coli pilus antigens. One group has reported data suggesting a loose linkage between K88 and EAL, now mapped to chromosome 4, whereas two other groups have found linkage between K88 and the transferrin locus (TF), mapped to chromosome 13 by in situ hybridization.     

Cloning and antigenic expression of two genes from Chlamydia psittaci avian strain

Abstract: Genes from Chlamydia psittaci P-1041 were cloned into the Bam HI site of pUC19 and were transformed to host Escherichia coli JM109. Two recombinant plasmids that expressed protein antigens of Chlamydia were isolated. The sizes of the DNA fragments were 1350 and 1710 bp, and encoded for polypeptides of M _r 25 and 42 kilodaltons (kDa), respectively. The 25-kDa protein had cross-reactivity with antisera to ten C. psittaci strains and two C. trachomatis strains, whereas the 42-kDa protein reacted only with homologous antiserum to the C. psittaci P-1041 strain. Furthermore, in Southern hybridization analysis these two fragments as probes hybridized with DNA of ten C. psittaci strains and four C. trachomatis strains. These results indicated that the two fragments shared a DNA sequence common to the chlamydial genus.     

Effects of exposure to short-term heat stress on fitness components in Drosophila melanogaster

Effects of thermal stress on survival and reproductive success in ten recently collected isofemale lines of Drosophila melanogaster were compared for flies treated as follows: always held at 25° C, placed in an incubator set at 37° C for 120 min, or exposed to 40° C in an incubator for 90 min, with or without previous exposure to 37° C. Short-term exposure to the higher temperature greatly reduced adult survival, the mating frequency of males and females, and female fecundity, which was measured as offspring produced over ten days. Male fertility, measured as the progeny produced by a female mated once, differed little among treatments. Previous exposure to a high, but non-lethal, temperature before exposure to the higher one, improved survival of males and females, and improved offspring production of females. Genetic variation was present among lines for offspring production, but genetic variation for survival was not significant, and genotype by environment interactions for fitness components of females were small. These results indicated low genetic variation in thermal resistance in the studied population, such that a threshold for temperature stress probably exists, above which local extinction is more likely than the evolution of resistance.     

The impact of hybrids between genetically modified crop plants and their related species: general considerations

Factors influencing the fate and impact of hybrids between crop plants and their related species operate from the early zygote, through to plant establishment in different habitats, to their ability to form self-sustaining populations. Many of the classes of genes being introduced by modern methods of genetic modification are similar to those manipulated by conventional plant breeding. In assessing the impact of transgenes in hybrids between crops and related species, therefore, it is important to be informed about the consequences of hybridization between conventionally bred varieties and their relatives. Some transgenes will have novel effects (e.g. production of pharmaceutical substances or certain fatty acids) on plants, and are likely to need specific assessment studies to determine their impact on hybrids. This will be particularly important if there is the possibility of these transgenes becoming established in wild populations. Some recommendations for further research are outlined.     

iPSC technology-Powerful hand for disease modeling and therapeutic screen

Cardiovascular and neurodegenerative diseases are major health threats in many developed countries. Recently, target tissues derived from human embryonic stem (hES) cells and induced pluripotent stem cells (iPSCs), such as cardiomyocytes (CMs) or neurons, have been actively mobilized for drug screening. Knowledge of drug toxicity and efficacy obtained using stem cell-derived tissues could parallel that obtained from human trials. Furthermore, iPSC disease models could be advantageous in the development of personalized medicine in various parts of disease sectors. To obtain the maximum benefit from iPSCs in disease modeling, researchers are now focusing on aging, maturation, and metabolism to recapitulate the pathological features seen in patients. Compared to pediatric disease modeling, adult-onset disease modeling with iPSCs requires proper maturation for full manifestation of pathological features. Herein, the success of iPSC technology, focusing on patient-specific drug treatment, maturation-based disease modeling, and alternative approaches to compensate for the current limitations of patient iPSC modeling, will be further discussed. [BMB Reports 2015; 48(5): 256-265]