Effect of microbial concentration on biodegradation rates of phenols

Summary Biodegradation rates of 12 phenols were measured with respect to acclimated microbial biomass ranging from 2.3×10⁴ to 2.3×10⁸ cells/l. Rates ranged between 0.02 mg l^–1 day^–1 for 1.6 mg/lp-bromophenol exposed to 2.3×10⁴ cells/l and 1.41 mg l^–1 day^–1 for 3.2 mg/lp-methylphenol exposed to 2.3×10⁸ cells/l. Generally, rates for all phenols were first-order in substrate concentration and zero-order in biomass concentration. Bromophenol biodegradation was preceded by lag periods of varying lengths and to a small extent the rate was dependent on microbial biomass. Results from this study suggest chemical biodegradation generally exhibits pseudo-first-and occasionally, second-order kinetics.     

Bigenic Cre/loxP, puDeltatk conditional genetic ablation

Genetic ablation experiments are used to resolve problems regarding cell lineages and the in vivo function of certain groups of cells. We describe a two-component conditional ablation technology using a mouse carrying an X-linked puDeltatk transgene, which is only activated in cells expressing Cre. Ablation of the Cre-expressing cells can be temporally regulated by the time of ganciclovir (GCV) administration. This strategy was demonstrated using a Col2Cre transgenic line. Differentiating chondrocytes in bigenic animals could be ablated at different developmental stages resulting in disorganized growth plates and dwarfism. Macrocephaly, macroglossia and umbilical hernia were also observed in ablated 18.5 dpc embryos. Crosses between the puDeltatk selector transgenic line and existing cre lines will facilitate numerous temporally regulated tissue-specific ablation experiments.     

Influence of Seed Biopriming and Vermiwash Treatment on Tomato Plant's Immunity and Nutritional Quality upon Sclerotium rolfsii Challenge Inoculation

Journal of Plant Growth Regulation - Tomato is an important nutritional vegetable crop and its nutrient contents are affected by both biotic and abiotic stresses. The main objective of this study...     

Protection against cellular stress by 25‐hydroxyvitamin D3 in breast epithelial cells

25‐Hydroxyvitamin D₃ (25(OH)D₃) is a prohormone and a major vitamin D metabolite. The discovery of (25(OH)D₃) 1α‐hydroxylase in many vitamin D target organs has yielded an increased interest in defining the role(s) of 25(OH)D₃ in these tissues. The etiology of cancer appears to be complex and multi‐factorial. Cellular stress (e.g., DNA damage, hypoxia, oncogene activation) has been identified as one of the key factors responsible for initiating the carcinogenesis process. In this study, we investigated whether 25(OH)D₃ protects breast epithelial cells from cellular stress using an established breast epithelial cell line MCF12F. To better elucidate the role of 25(OH)D₃ in the stress response, we used multiple in vitro stress models including serum starvation, hypoxia, oxidative stress, and apoptosis induction. Under all these stress conditions, 25(OH)D₃ (250 nmol/L) treatment significantly protected cells against cell death. Low‐serum stress induced p53 expression accompanied with downregulation of PCNA, the presence of 25(OH)D₃ consistently inhibited the alteration of p53 and PCNA, suggesting that these molecules were involved in the stress process and may be potential target genes of 25(OH)D₃. miRNA microarray analysis demonstrated that stress induced by serum starvation caused significant alteration in the expression of multiple miRNAs including miR182, but the presence of 25(OH)D₃ effectively reversed this alteration. These data suggest that there is a significant protective role for 25(OH)D₃ against cellular stress in the breast epithelial cells and these effects may be mediated by altered miRNA expression. J. Cell. Biochem. 110: 1324–1333, 2010. © 2010 Wiley‐Liss, Inc.     

Stress Distribution in the Canine Left Ventricle during Diastole and Systole

A model is proposed for stress analysis of the left ventricular wall (LV wall) based on the realistic assumption that the myocardium is essentially composed of fiber elements which carry only axial tension and vary in orientation through the wall. Stress analysis based on such a model requires an extensive study of muscle fiber orientation and curvature through the myocardium. Accordingly, the principal curvatures were studied at a local site near the equator in ten dog hearts rapidly fixed in situ at end diastole and end systole; the fiber orientation for these hearts had already been established in a previous study. The principal radii of curvature were (a) measured by fitting templates to the endocardial and epicardial wall surfaces in the circumferential and longitudinal directions and (b) computed from measured lengths of semiaxes of ellipsoids of revolution representing the LV wall (“ellipsoid” data). The wall was regarded as a tethered set of nested shells, each having a unique fiber orientation. Results indicate the following. (a) Fiber curvature, k, is maximum at midwall at end systole; this peak shifts towards endocardium at end diastole. (b) The pressure or radial stress through the wall decreases more rapidly near the endocardium than near the epicardium at end diastole and at end systole when a constant tension is assumed for each fiber through the wall. (c) At end diastole the curve for the circumferential stress vs. wall thickness is convex with a maximum at midwall. In the longitudinal direction the stress distribution curve is concave with a minimum at midwall. Similar distributions are obtained at end systole when a constant tension is assumed for each fiber through the wall. (d) The curvature and stress distributions obtained by direct measurements at a selected local site agree well with those computed from “ellipsoid” data.     

The effect of antibacterial drugs on the growth kinetics ofBacteroides in vitro

Current Microbiology - A method is described to express the effect of antimicrobial drugs on the growthin vitro of variousBacteroides species during the first few hours of exposure. Drugs studied...     

Bigenic Cre/loxP, puΔtk conditional genetic ablation

Genetic ablation experiments are used to resolve problems regarding cell lineages and the in vivo function of certain groups of cells. We describe a two-component conditional ablation technology using a mouse carrying an X-linked puΔtk transgene, which is only activated in cells expressing Cre. Ablation of the Cre-expressing cells can be temporally regulated by the time of ganciclovir (GCV) administration. This strategy was demonstrated using a Col2Cre transgenic line. Differentiating chondrocytes in bigenic animals could be ablated at different developmental stages resulting in disorganized growth plates and dwarfism. Macrocephaly, macroglossia and umbilical hernia were also observed in ablated 18.5 dpc embryos. Crosses between the puΔtk selector transgenic line and existing cre lines will facilitate numerous temporally regulated tissue-specific ablation experiments.     

Natural products for cancer chemotherapy

For over 40 years, natural products have served us well in combating cancer. The main sources of these successful compounds are microbes and plants from the terrestrial and marine environments. The microbes serve as a major source of natural products with anti‐tumour activity. A number of these products were first discovered as antibiotics. Another major contribution comes from plant alkaloids, taxoids and podophyllotoxins. A vast array of biological metabolites can be obtained from the marine world, which can be used for effective cancer treatment. The search for novel drugs is still a priority goal for cancer therapy, due to the rapid development of resistance to chemotherapeutic drugs. In addition, the high toxicity usually associated with some cancer chemotherapy drugs and their undesirable side‐effects increase the demand for novel anti‐tumour drugs active against untreatable tumours, with fewer side‐effects and/or with greater therapeutic efficiency. This review points out those technologies needed to produce the anti‐tumour compounds of the future.