Water quality and antibiotic resistance in the recreational waters.

The overuse and improper disposal of antibiotics results in antibiotic resistance. This raises concern over the presence of antibiotic resistant bacteria (ARB) in waterways and pose health risks of antibiotic resistant infections to water recreationists. The purpose of this study was to monitor water quality, microbial ecology, and antibiotic resistance in water and biofilm on submerged plastics at two public boat launches in southeastern Louisiana. Water and biofilm samples were collected once a month, in triplicate, from two public boat launches in Louisiana, USA for a year. Water quality metrics included nitrate, ammonia, sulfate, phosphate, and organic carbon. Water samples were tested for total and fecal coliform abundance and the presence of ARB. Out of 131 bacterial isolates studied from these two sites, 86% of them tested positive for antibiotic resistance with multi-drug resistance. Antibiotic resistance genes (ARGs) for sulfonamide (sul2), bacitracin (bacA) and ampicillin (ampA) were identified in bacterial isolates from water and biofilm samples at both sites. Molecular genetic diversity analysis identified distinct taxonomic diversity differences in biofilm bacteria compared to the planktonic bacteria in the surrounding water. Biofilm samples showed increased diversity at the phylum, genus, and species levels.

R1 retrotransposons in the nucleolar organizers of Drosophila melanogaster are transcribed by RNA polymerase I upon heat shock.

The ribosomal RNA genes (rDNA) of Drosophila melanogaster reside within centromere-proximal nucleolar organizers on both the X and Y chromosomes. Each locus contains between 200-300 tandem repeat rDNA units that encode 18S, 5.8S, 2S, and 28S ribosomal RNAs (rRNAs) necessary for ribosome biogenesis. In arthropods like Drosophila, about 60% of the rDNA genes have R1 and/or R2 retrotransposons inserted at specific sites within their 28S regions; these units likely fail to produce functional 28S rRNA. We showed earlier that R2 expression increases upon nucleolar stress caused by the loss of the ribosome assembly factor, Nucleolar Phosphoprotein of 140 kDa (Nopp140). Here we show that R1 expression is selectively induced by heat shock. Actinomycin D, but not α-amanitin, blocked R1 expression in S2 cells upon heat shock, indicating that R1 elements are transcribed by Pol I. A series of RT-PCRs established read-through transcription by Pol I from the 28S gene region into R1. Sequencing the RT-PCR products confirmed the 28S-R1 RNA junction and the expression of R1 elements within nucleolar rDNA rather than R1 elements known to reside in centromeric heterochromatin. Using a genome-wide precision run-on sequencing (PRO-seq) data set available at NCBI-GEO, we show that Pol I activity on R1 elements is negligible under normal non-heat shock conditions but increases upon heat shock. We propose that prior to heat shock Pol I pauses within the 5' end of R1 where we find a consensus "pause button", and that heat shock releases Pol I for read-through transcription farther into R1.

Deletion of Drosophila Nopp140 induces subcellular ribosomopathies.

The nucleolar and Cajal body phosphoprotein of 140 kDa (Nopp140) is considered a ribosome assembly factor, but its precise functions remain unknown. To approach this problem, we deleted the Nopp140 gene in Drosophila using FLP-FRT recombination. Genomic PCR, reverse transcriptase-PCR (RT-PCR), and immunofluorescence microscopy confirmed the loss of Nopp140, its messenger RNA (mRNA), and protein products from all tissues examined. Nopp140-/- larvae arrested in the second instar stage and most died within 8 days. While nucleoli appeared intact in Nopp140-/- cells, the C/D small nucleolar ribonucleoprotein (snoRNP) methyltransferase, fibrillarin, redistributed to the nucleoplasm in variable amounts depending on the cell type; RT-PCRs showed that 2'-O-methylation of ribosomal RNA (rRNA) in Nopp140-/- cells was reduced at select sites within both the 18S and 28S rRNAs. Ultrastructural analysis showed that Nopp140-/- cells were deficient in cytoplasmic ribosomes, but instead contained abnormal electron-dense cytoplasmic granules. Immunoblot analysis showed a loss of RpL34, and metabolic labeling showed a significant drop in protein translation, supporting the loss of functional ribosomes. Northern blots showed that pre-RNA cleavage pathways were generally unaffected by the loss of Nopp140, but that R2 retrotransposons that naturally reside within the 28S region of normally silent heterochromatic Drosophila ribosomal DNA (rDNA) genes were selectively expressed in Nopp140-/- larvae. Unlike copia elements and the related R1 retrotransposon, R2 expression appeared to be preferentially dependent on the loss of Nopp140 and not on environmental stresses. We believe the phenotypes described here define novel intracellular ribosomopathies resulting from the loss of Nopp140.

Nucleolar stress with and without p53.

A veritable explosion of primary research papers within the past 10 years focuses on nucleolar and ribosomal stress, and for good reason: with ribosome biosynthesis consuming ~80% of a cell's energy, nearly all metabolic and signaling pathways lead ultimately to or from the nucleolus. We begin by describing p53 activation upon nucleolar stress resulting in cell cycle arrest or apoptosis. The significance of this mechanism cannot be understated, as oncologists are now inducing nucleolar stress strategically in cancer cells as a potential anti-cancer therapy. We also summarize the human ribosomopathies, syndromes in which ribosome biogenesis or function are impaired leading to birth defects or bone narrow failures; the perplexing problem in the ribosomopathies is why only certain cells are affected despite the fact that the causative mutation is systemic. We then describe p53-independent nucleolar stress, first in yeast which lacks p53, and then in other model metazoans that lack MDM2, the critical E3 ubiquitin ligase that normally inactivates p53. Do these presumably ancient p53-independent nucleolar stress pathways remain latent in human cells? If they still exist, can we use them to target >50% of known human cancers that lack functional p53?

Prevalence of metabolic syndrome in urban India.

Background. Metabolic syndrome (MS) is characterised by a constellation of individual risk factors of cardiovascular disease. Materials and Methods. The current study was a population-based survey of cohort of subjects in the metropolitan city of Mumbai. A total of 548 subjects, who attended the CARDIAC evaluation camp, were recruited in the study. Participants with complete fasting lipid profiles, blood glucose, and known cardiac risk markers were evaluated. Results. On applying modified NCEP ATP III, we found out that nearly 95% of the subjects had at least one abnormal parameter. We found the prevalence of MS in our study population to be 19.52%. The prevalence of MS in males was almost double than females (P = .008). The overall prevalence of BMI (>23 kg/m(2)) was 79.01%. Increased hypertriglyceridemia and decreased levels of HDL-C were found to be more in males (P < .0001). Conclusion. The low percentage of subjects with normal and controlled parameters suggests that there is a need for awareness programs and lifestyle interventions for the prevention and control of MS.

Design of Allele Specific PCR for Rapid Detection of CYP3A5 (A6986G) and Mdr-1 (C3435T) Polymorphisms.

Single nucleotide polymorphisms in CYP3A5 (A6986G) and MDR-1 (C3435T) genes have been shown to be associated with the pharmacokinetics of tacrolimus in case of renal transplant recipients. Knowing these genotypes of the recipients before undergoing transplantation, is therefore essential for physicians to adjust the starting dose of tacrolimus in order to avoid drug induced nephrotoxicity. We have designed an allele specific PCR method for easier and rapid detection of these polymorphisms. 20 Indian renal transplant recipients on tacrolimus who developed nephrotoxicity within 1 month of transplantation and 58 Indian non-transplant subjects having the risk factors for kidney disease i.e. hypertension or diabetes or the family history of these, have been studied for these SNPs by allele specific PCR method. The data suggest that the heterozygosity of CYP3A5 and mutant allele frequency of MDR-1 SNP is higher in transplant patients as well as in general population.