A note on the characterization of an estuarine microbial community enriched with the herbicide Fenuron

M inney , S.F., P arkes , R.J. & B ull , A.T. 1985. A note on the characterization of an estuarine microbial community enriched with the herbicide Fenuron. Journal of Applied Bacteriology 59 , 17—22.
A stable, five-membered estuarine microbial community was enriched in the presence of 1,1 dimethyl-3-phenylurea (Fenuron), phenylurea and aniline. At a dilution rate of 0μD01/h in the chemostat, partial aniline utilization occurred and the rate increased with dilution rate. At the higher dilution rates the phenylurea component was also utilized. At a dilution rate of mD015/h in a fluidized bed system, complete removal of both aniline and phenylurea occurred. There was no evidence of Fenuron degradation under any of the conditions examined. The importance of the use of heterogeneous culture conditions in the laboratory is discussed.     

Speciation of tissue and cellular iron with on-line detection by inductively coupled plasma-mass spectrometry.

Iron accumulating to excess in tissues of humans and animal models occurs mainly as complexes with transferrin, ferritin, other hemoproteins, and insoluble hemosiderin particles. To determine the distribution of Fe amongst these molecular species, we have used inductively coupled plasma-mass spectrometry as a means of on-line, isotope-specific detection for their liquid chromatographic separation. The stable isotope 57Fe is a suitable isotope for monitoring the Fe content of each fraction, and its availability at high isotopic enrichment makes it an attractive choice for tracer studies when the use of a radioisotope is undesirable, e.g., in human subjects. The detection system offers the advantages of high sensitivity (detection limits in the parts per billion range), a wide dynamic range (linearity of the calibration curve over several orders of magnitude), and on-line analysis facilitating real-time evaluation of the chromatographic separation, in addition to isotope-specific information. The Fe distributions in healthy rat livers, liver and heart tissue from Fe-loaded human subjects, and human hepatocyte cultures are reported. The ferritin:hemosiderin ratio in these samples is shown to be an indicator of the degree of Fe loading and correlates well with that determined by Zeeman-corrected electrothermal atomic absorption as an alternative means of detection.     

DNA extraction for 16S rRNA gene analysis to determine genetic diversity in deep sediment communities

A protocol was devised which permitted the extraction of DNA from deep marine sediments up to 503 m below the sea floor. These sediments have been laid down over the last 3 million years. 16S rRNA gene sequences were amplified from the DNA by the polymerase chain reaction. The details of the successful extraction and polymerase chain reaction methodology varied between samples from different depths. This emphasizes the attention to detail required to allow the diversity of bacteria in these deep sediments to be studied.     

Exenatide does not evoke pancreatitis and attenuates chemically induced pancreatitis in normal and diabetic rodents

The risk of developing pancreatitis is elevated in type 2 diabetes and obesity. Cases of pancreatitis have been reported in type 2 diabetes patients treated with GLP-1 (GLP-1R) receptor agonists. To examine whether the GLP-1R agonist exenatide potentially induces or modulates pancreatitis, the effect of exenatide was evaluated in normal or diabetic rodents. Normal and diabetic rats received a single exenatide dose (0.072, 0.24, and 0.72 nmol/kg) or vehicle. Diabetic ob/ob or HF-STZ mice were infused with exenatide (1.2 and 7.2 nmol·kg(-1)·day(-1)) or vehicle for 4 wk. Post-exenatide treatment, pancreatitis was induced with caerulein (CRN) or sodium taurocholate (ST), and changes in plasma amylase and lipase were measured. In ob/ob mice, plasma cytokines (IL-1β, IL-2, IL-6, MCP-1, IFNγ, and TNFα) and pancreatitis-associated genes were assessed. Pancreata were weighed and examined histologically. Exenatide treatment alone did not modify plasma amylase or lipase in any models tested. Exenatide attenuated CRN-induced release of amylase and lipase in normal rats and ob/ob mice but did not modify the response to ST infusion. Plasma cytokines and pancreatic weight were unaffected by exenatide. Exenatide upregulated Reg3b but not Il6, Ccl2, Nfkb1, or Vamp8 expression. Histological analysis revealed that the highest doses of exenatide decreased CRN- or ST-induced acute inflammation, vacuolation, and acinar single cell necrosis in mice and rats, respectively. Ductal cell proliferation rates were low and similar across all groups of ob/ob mice. In conclusion, exenatide did not modify plasma amylase and lipase concentrations in rodents without pancreatitis and improved chemically induced pancreatitis in normal and diabetic rodents.     

Cumulus expansion is impaired with advanced reproductive age due to loss of matrix integrity and reduced hyaluronan

Reproductive aging is associated with ovulatory defects. Age-related ovarian fibrosis partially contributes to this phenotype as short-term treatment with anti-fibrotic compounds improves ovulation in reproductively old mice. However, age-dependent changes that are intrinsic to the follicle may also be relevant. In this study, we used a mouse model to demonstrate that reproductive aging is associated with impaired cumulus expansion which is accompanied by altered morphokinetic behavior of cumulus cells as assessed by time-lapse microscopy. The extracellular matrix integrity of expanded cumulus–oocyte complexes is compromised with advanced age as evidenced by increased penetration of fluorescent nanoparticles in a particle exclusion assay and larger open spaces on scanning electron microscopy. Reduced hyaluronan (HA) levels, decreased expression of genes encoding HA-associated proteins (e.g., Ptx3 and Tnfaip6), and increased expression of inflammatory genes and matrix metalloproteinases underlie this loss of matrix integrity. Importantly, HA levels are decreased with age in follicular fluid of women, indicative of conserved reproductive aging mechanisms. These findings provide novel mechanistic insights into how defects in cumulus expansion contribute to age-related infertility and may serve as a target to extend reproductive longevity.