Genetic differentiation between natural populations of Drosophila subobscura in the Western Mediterranean Area with respect to chromosomal variation

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Hypercholesterolemia Impaired Sperm Functionality in Rabbits

Hypercholesterolemia represents a high risk factor for frequent diseases and it has also been associated with poor semen quality that may lead to male infertility. The aim of this study was to analyze semen and sperm function in diet-induced hypercholesterolemic rabbits. Twelve adult White New Zealand male rabbits were fed ad libitum a control diet or a diet supplemented with 0.05% cholesterol. Rabbits under cholesterol-enriched diet significantly increased total cholesterol level in the serum. Semen examination revealed a significant reduction in semen volume and sperm motility in hypercholesterolemic rabbits (HCR). Sperm cell morphology was seriously affected, displaying primarily a “folded head”-head fold along the major axe-, and the presence of cytoplasmic droplet on sperm flagellum. Cholesterol was particularly increased in acrosomal region when detected by filipin probe. The rise in cholesterol concentration in sperm cells was determined quantitatively by Gas chromatographic-mass spectrometric analyses. We also found a reduction of protein tyrosine phosphorylation in sperm incubated under capacitating conditions from HCR. Interestingly, the addition of Protein Kinase A pathway activators -dibutyryl-cyclic AMP and iso-butylmethylxanthine- to the medium restored sperm capacitation. Finally, it was also reported a significant decrease in the percentage of reacted sperm in the presence of progesterone. In conclusion, our data showed that diet-induced hypercholesterolemia adversely affects semen quality and sperm motility, capacitation and acrosomal reaction in rabbits; probably due to an increase in cellular cholesterol content that alters membrane related events

Ultrastructural changes.

<p>Transmission<b>-</b>electron micrographs of rabbit sperm heads from NCR (A) and HCR (B to D). Notice the small vesicles in the acrosome region in B and the long side fold of sperm head in D. Some sperm cells show the remaining residual body (white empty arrow, C). A and C, X 12,000; B and D, X 20,000.</p

Rabbits fed with fat-rich diet increased plasma cholesterol.

<p>Plasma cholesterol concentration from NCR (•) and HCR (<b>□</b>) during the 11 experimental months. Values are expressed as mean ± SEM. Arrowhead indicates fat intake start in HCR, and arrow indicates the moment from which HCR weight resulted significantly different from NCR, (p<0.001).</p

Saturated-fat consumption damaged sperm plasma membrane in rabbits.

<p>Photographs (X 250) represent sperm cell morphology after hypo-osmotic stress. A (NCR): normal coiled tails and B (HCR): straight tails. C: Bars represent the percentage (means ± SEM) of spermatozoa swollen from NCR (black bar) and HCR (white bar) rabbits. **  =  significantly different from control (p<0.01).</p

General characteristics of fresh rabbit semen samples (mean ± SEM).

<p>*p<0.001, <i>n</i> = 25.</p

Microbial population analysis of nutrient removal-related organisms in membrane bioreactors

Membrane bioreactors (MBR) are an important and increasingly implemented wastewater treatment technology, which are operated at low food to microorganism ratios (F/M) and retain slow-growing organisms. Enhanced biological phosphorus removal (EBPR)-related organisms grow slower than ordinary heterotrophs, but have never been studied in detail in MBRs. This study presents a comprehensive analysis of the microorganisms involved in EBPR in pilot- and full-scale MBRs, using fluorescence in situ hybridization (FISH), as well as an overall assessment of other relevant microbial groups. The results showed that polyphosphate accumulating organisms (PAOs) were present at similar levels in all studied MBRs (10%±6%), even those without a defined anaerobic zone. Glycogen accumulating organisms were also detected, although rarely. The FISH results correlated well with the observed P removal performance of each plant. The results from this study suggest that a defined anaerobic zone is not necessarily required for putative PAO growth in MBRs, since polyphosphate storage may provide a selective advantage in fulfilling cell maintenance requirements in substrate-limited conditions (low F/M).Water ManagementCivil Engineering and Geoscience