Characteristics of a novel Acinetobacter sp. and its kinetics in hexavalent chromium bioreduction

Cr-B2, a Gram-negative hexavalent chromium [Cr(VI)] reducing bacteria, was isolated from the aerator water of an activated sludge process in the wastewater treatment facility of a dye and pigment based chemical industry. Cr- B2 exhibited a resistance for 1,100 mg/l Cr(VI) and, similarly, resistance against other heavy metal ions such as Ni2+ (800 mg/l), Cu2+ (600 mg/l), Pb2+ (1,100 mg/l), Cd2+ (350 mg/l), Zn2+ (700 mg/l), and Fe3+ (1,000 mg/l), and against selected antibiotics. Cr-B2 was observed to efficiently reduce 200 mg/l Cr(VI) completely in both nutrient and LB media, and could convert Cr(VI) to Cr(III) aerobically. Cr(VI) reduction kinetics followed allosteric enzyme kinetics. The Km values were found to be 43.11 mg/l for nutrient media and 38.05 mg/l for LB media. Vmax values of 13.17 mg/l/h and 12.53 mg/l/h were obtained for nutrient media and LB media, respectively, and the cooperativity coefficients (n) were found to be 8.47 and 3.49, respectively, indicating positive cooperativity in both cases. SEM analysis showed the formation of wrinkles and depressions in the cells when exposed to an 800 mg/l Cr(VI) concentration. The organism was seen to exhibit pleomorphic behavior. Cr-B2 was identified on the basis of morphological, biochemical, and partial 16S rRNA gene sequencing chracterizations and found to be Acinetobacter sp.     

How We Choose One over Another: Predicting Trial-by-Trial Preference Decision

Preference formation is a complex problem as it is subjective, involves emotion, is led by implicit processes, and changes depending on the context even within the same individual. Thus, scientific attempts to predict preference are challenging, yet quite important for basic understanding of human decision making mechanisms, but prediction in a group-average sense has only a limited significance. In this study, we predicted preferential decisions on a trial by trial basis based on brain responses occurring before the individuals made their decisions explicit. Participants made a binary preference decision of approachability based on faces while their electrophysiological responses were recorded. An artificial neural network based pattern-classifier was used with time-frequency resolved patterns of a functional connectivity measure as features for the classifier. We were able to predict preference decisions with a mean accuracy of 74.3±2.79% at participant-independent level and of 91.4±3.8% at participant-dependent level. Further, we revealed a causal role of the first impression on final decision and demonstrated the temporal trajectory of preference decision formation.     

T2384, a novel antidiabetic agent with unique peroxisome proliferator-activated receptor gamma binding properties

The nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARgamma) plays central roles in adipogenesis and glucose homeostasis and is the molecular target for the thiazolidinedione (TZD) class of antidiabetic drugs. Activation of PPARgamma by TZDs improves insulin sensitivity; however, this is accompanied by the induction of several undesirable side effects. We have identified a novel synthetic PPARgamma ligand, T2384, to explore the biological activities associated with occupying different regions of the receptor ligand-binding pocket. X-ray crystallography studies revealed that T2384 can adopt two distinct binding modes, which we have termed "U" and "S", interacting with the ligand-binding pocket of PPARgamma primarily via hydrophobic contacts that are distinct from full agonists. The different binding modes occupied by T2384 induced distinct patterns of coregulatory protein interaction with PPARgamma in vitro and displayed unique receptor function in cell-based activity assays. We speculate that these unique biochemical and cellular activities may be responsible for the novel in vivo profile observed in animals treated systemically with T2384. When administered to diabetic KKAy mice, T2384 rapidly improved insulin sensitivity in the absence of weight gain, hemodilution, and anemia characteristics of treatment with rosiglitazone (a TZD). Moreover, upon coadministration with rosiglitazone, T2384 was able to antagonize the side effects induced by rosiglitazone treatment alone while retaining robust effects on glucose disposal. These results are consistent with the hypothesis that interactions between ligands and specific regions of the receptor ligand-binding pocket might selectively trigger a subset of receptor-mediated biological responses leading to the improvement of insulin sensitivity, without eliciting less desirable responses associated with full activation of the receptor. We suggest that T2384 may represent a prototype for a novel class of PPARgamma ligand and, furthermore, that molecules sharing some of these properties would be useful for treatment of type 2 diabetes.     

Onychomycosis Incidence in Type 2 Diabetes Mellitus Patients

The onychomycosis incidence was determined in 250 type 2 diabetes mellitus (T2DM) patients who were registered at the Internal Medicine Service from a Mexico city General Hospital throughout a year (January-December 2006). Out of the total of studied T2DM patients, 93 (37.2%) showed ungual dystrophy and from these, in 75.3% a fungal etiology was corroborated. Out of 70 patients, 34 were men and 36 women, with an average of 63.5 years. Correlation between T2DM evolution time and onychomycosis was significant (P < 0.01). Distal-lateral subungual and total dystrophic onychomycosis were the most frequent clinical types (55.1% and 33.7%, respectively). Fifty-eight fungal isolates were obtained; 48.6% corresponded to dermatophytes, Trichophyton rubrum being the first species (37.1%). All these strains corresponded to two morphological varieties: "yellow" and typical downy. From the yeast-like isolates, 12 corresponded to Candida spp., firstly C. albicans and C. parapsilosis; three to Cryptococcus spp. (C. albidus, C. uniguttulatus and C. laurentii); two Trichosporon asahii; and only one to Pichia ohmeri. Six non-dermatophytic molds were isolated: two Chrysosporium keratinophylus, two Scopulariopsis brevicaulis, one Aspergillus fumigatus, and one Acremonium sp. The fungal mixture corresponded to T. mentagrophytes with C. guilliermondii; T. mentagrophytes with C. glabrata; T. rubrum with C. glabrata; T. rubrum with P. ohmeri.     

Isolation and characterization of tri‐ and tetranucleotide microsatellite loci in the Asian elephant,Elephas maximus

Asian elephants (Elephas maximus) are an endangered species. Their future survival depends on intensive conservation and management, based on in‐depth knowledge of particular populations. Molecular genetic methods, especially microsatellite analysis through noninvasive sampling, provides an effective means of obtaining such information. The use of tri‐ and tetranucleotide microsatellite markers is advantageous in noninvasive sampling through dung analysis. Here we describe the isolation and characterization of five tri‐ and tetranucleotide markers in the Asian elephant. All five loci were found to be polymorphic in a sample of 20 Asian elephants from Sri Lanka.     

Lipolysis in Adipocytes Isolated from Deep and Superficial Subcutaneous Adipose Tissue

Objective: Abdominal subcutaneous adipose tissue (SAT) occurs in two depots separated by a fascial plane: deep SAT and superficial SAT. In a recent study it was demonstrated that the amount of deep SAT has a much stronger relationship to insulin resistance than does superficial SAT. Because insulin resistance may be related to fatty acid release from adipose tissue, we hypothesized that the two SAT depots may have a different lipolytic activity. Research Methods and Procedures: To test this hypothesis, we obtained samples of deep and superficial SAT from patients undergoing elective abdominal surgery. The rate of lipolysis was determined in the collagenase‐digested adipocytes obtained from the two fat depots by measuring glycerol release in the presence and absence of isoproterenol. In addition, the relative concentration of hormone‐sensitive lipase was determined in both SAT depots by Western blot analysis. Results: Our results showed that the rate of isoproterenol‐stimulated lipolysis was ～20% higher in cells from deep SAT compared with those from superficial SAT, indicating that the deep SAT is more lipolytically active. The concentration of hormone‐sensitive lipase did not differ between the two adipose tissue depots. Discussion: These findings suggest that the higher lipolytic activity of deep SAT may account for its stronger association with insulin resistance. The mechanism seems to be independent of differences in hormone‐sensitive lipase concentration.     

Activin disrupts somitogenesis in cultured chick embryos

The anatomical and cell biological aspects of somite formation in the chick embryo have been rather well studied. Molecular regulation of somitogenesis in vertebrates is just beginning to be understood. We have studied the effects of human recombinant activin on somitogenesis in gastrulating chick embryos cultured in vitro with a view to assessing the possible role of activin-related molecules in this phenomenon. Activin disrupted somitogenesis in treated embryos, resulting in the formation of abnormal, split or ectopic somites. Light microscopic examination indicated that the ability of activin to interfere with somitogenesis might be partly due to initiation of somite formation at ectopic sites. We show that these cells are indeed somitogenic by their expression of one of the earliest somite-specific marker genes, Pax3. Scanning electron microscopic examination of control and treated embryos revealed direct effects of activin on cell-cell interactions. Cells from treated embryos exhibited disrupted intercellular adhesion leading to large intercellular spaces, altered cell shapes and modification of cell surface protrusions. The effects of activin on somitogenesis appear to be specific, since the neural structures, which are generally more susceptible to chemical insults during gastrulation, were relatively less affected. The results clearly point to a role of activin-related molecules in somitogenesis in the chick embryo.     

Krt6a-Positive Mammary Epithelial Progenitors Are Not at Increased Vulnerability to Tumorigenesis Initiated by ErbB2

While most breast cancers are thought to arise from the luminal layer of the breast tissue, it remains unclear which specific cells in the luminal layer are the cells of origin of breast cancer. We have previously reported that WAP-positive luminal epithelial cells are at increased susceptibility to tumor initiation by ErbB2 compared to the bulk population, while the mammary cells with canonical Wnt signaling activity fail to evolve into tumors upon ErbB2 activation. Here, we used retrovirus to introduce ErbB2 into the Krt6a-positive mammary progenitor subset of the luminal epithelium and, for comparison, into the mammary luminal epithelium indiscriminately. Tumors developed from both groups of cells with a similar latency. These data indicate that the Krt6a-positive subset of mammary epithelial cells can be induced to form cancer by ErbB2 but it is not more susceptible to tumorigenesis initiated by ErbB2 than the bulk population of the luminal epithelium.     

High-Throughput Profiling of Caenorhabditis elegans Starvation-Responsive microRNAs

MicroRNAs (miRNAs) are non-coding RNAs of ~22 nucleotides in length that regulate gene expression by interfering with the stability and translation of mRNAs. Their expression is regulated during development, under a wide variety of stress conditions and in several pathological processes. In nature, animals often face feast or famine conditions. We observed that subjecting early L4 larvae from Caenorhabditis elegans to a 12-hr starvation period produced worms that are thinner and shorter than well-fed animals, with a decreased lipid accumulation, diminished progeny, reduced gonad size, and an increased lifespan. Our objective was to identify which of the 302 known miRNAs of C. elegans changed their expression under starvation conditions as compared to well-fed worms by means of deep sequencing in early L4 larvae. Our results indicate that 13 miRNAs (miR-34-3p, the family of miR-35-3p to miR-41-3p, miR-39-5p, miR-41-5p, miR-240-5p, miR-246-3p and miR-4813-5p) were upregulated, while 2 miRNAs (let-7-3p and miR-85-5p) were downregulated in 12-hr starved vs. well-fed early L4 larvae. Some of the predicted targets of the miRNAs that changed their expression in starvation conditions are involved in metabolic or developmental process. In particular, miRNAs of the miR-35 family were upregulated 6–20 fold upon starvation. Additionally, we showed that the expression of gld-1, important in oogenesis, a validated target of miR-35-3p, was downregulated when the expression of miR-35-3p was upregulated. The expression of another reported target, the cell cycle regulator lin-23, was unchanged during starvation. This study represents a starting point for a more comprehensive understanding of the role of miRNAs during starvation in C. elegans.