Volatile metabolites from actinomycetes

Twenty-six Streptomyces spp. were screened for their volatile production capacity on yeast starch agar. The volatile organic compounds (VOCs) were concentrated on a porous polymer throughout an 8-day growth period. VOCs were analyzed by gas chromatography with flame ionization detection and identified or characterized by gas chromatography-mass spectrometry. A total of 120 VOCs were characterized by retention index and mass spectra. Fifty-three compounds were characterized as terpenoid compounds, among which 18 could be identified. Among the VOCs were alkanes, alkenes, alcohols, esters, ketones, sulfur compounds, and isoprenoid compounds. Among the most frequently produced compounds were isoprene, acetone, 1-butanol, 2-methyl-1-propanol, 3-methyl-3-buten-1-ol, 3-methyl-1-butanol, 2-methyl-1-butanol, cyclopentanone, dimethyl disulfide, dimethyl trisulfide, 2-phenylethanol, and geosmin. The relationship between the excretion of geosmin and the production of spores was examined for one isolate. A good correlation between headspace geosmin and the number of spores was observed, suggesting that VOCs could be used to indicate the activity of these microorganisms in heterogeneous substrates.     

Preparative enzymatic synthesis of glucuronides of zearalenone and five of its metabolites

The resorcylic acid lactones zearalenone ( 1), alpha-zearalenol ( 2), beta-zearalenol ( 3), alpha-zearalanol (zeranol) ( 4), beta-zearalanol (taleranol) ( 5), and zearalanone ( 6) were converted to their glucuronides on a preparative scale in good yields. Reactions were conducted with bovine uridine 5'-diphosphoglucuronyl transferase (UDPGT) as catalyst and uridine 5'-diphosphoglucuronic acid (UDPGA) as cofactor. The glucuronides were isolated by column chromatography and characterized by NMR spectroscopy and mass spectrometry. Although the principal products were 4- O-glucuronides (i.e., linkage through a phenolic hydroxyl), significant quantities of the 6'- O-glucuronides (i.e., linkage through the aliphatic hydroxyl) of alcohols 2, 4, and 5 were also isolated. In the case of 3, the 2- O-glucuronide was isolated as the minor product. Overall isolated yields of glucuronides, performed on a 20-50 mg scale, were typically ca. 80% based on the resorcylic acid lactone starting material. LC-UV-MS (2) analysis of purified specimens revealed MS (2) fragmentations useful for defining the point of attachment of the glucuronide moiety to the zearalenone nucleus.     

Single layer centrifugation of fresh dromedary camel semen improves sperm quality and in vitro fertilization capacity compared with simple sperm washing

Single layer centrifugation (SLC) through a colloid is a tool for selecting viable mammalian spermatozoa but has not been used previously for fresh dromedary camel sperm. Semen from six camels (2 ejaculates/male) was diluted 1:5 (v:v) or 1:10 (v:v) in a Tris–citrate–fructose buffer for mechanical liquefaction by gentle pipetting. Following liquefaction, semen was processed either by SLC or by centrifugation without a colloid (control). Total and progressive motilities, CASA kinematics, vitality and acrosome integrity (eosin–nigrosin) and plasma membrane integrity (Hypo‐osmotic swelling test; HOST), and fertilizing ability in a heterologous assay (zona‐free goat oocytes) were evaluated. Both total (p = .003) and progressive motilities (p = .003) were higher in SLC‐processed than in control semen samples, irrespective of dilution. Positive HOST values increased when using colloid in 1:5 (p = .001) and 1:10 dilution (p = .010). Colloid‐selected sperm had higher penetration rates than controls (p < .001 and p = .02 for 1:5 and 1:10 dilutions, respectively). However, only the SLC sperm at 1:5 dilution showed higher percentages of pronuclear formation (p = .02) than controls. Dilution effect was only significant for total motility before in vitro fertilization, with higher values for the 1:5 dilution (p = .033). The recovery rates of motile sperm between dilutions were similar (26.1% vs 35.4%; p = .226). In conclusion, SLC is a promising tool for selecting functional dromedary camel sperm and warrants more research.     

Persistence of passively transferred antibodies in porcine Taenia solium cysticercosis. Cysticercosis Working Group in Peru.

We evaluated the presence and persistence of anticysticercal antibodies in piglets born to Taenia solium infected sows. Infected sows from a disease-endemic area of Peru were transported to a nondisease-endemic area and impregnated. Serum samples were collected from sows and piglets on Day 2 through Week 35 after birth. Using an immunoblot specific for cysticercosis, Ig isotypes to 7 cyst antigens were measured and quantified. Serum samples from the piglets contained detectable antibodies from Week 1 through Week 35 (27 weeks after weaning). The primary Ig isotype present in both sows and piglets was IgG. Antibodies did not appear in piglet serum samples until after suckling, demonstrating that anti-cysticercal antibodies are transferred solely via colostrum. Our data have shown that maternally transferred antibodies to cyst antigens may persist through much of a pig's life. Therefore, the presence of passively transferred antibodies must be considered in studies that examine the prevalence of cysticercosis in pigs. Furthermore, when designing control strategies for cysticercosis, careful evaluation and selection of sentinel pigs becomes a crucial component of sentinel selection.     

Thyroxine concentrations are elevated in mares which continue to exhibit estrous cycles during the nonbreeding season

In two successive years, the pattern of secretion of thyroxine was compared in seasonally anestrous mares and a subpopulation of mares that exhibited estrous cycles during the nonbreeding season. Blood samples were collected two or three times per week between October and April from a total of 15 mares that exhibited estrous cycles during the nonbreeding season and 21 anestrous mares. Monthly mean concentrations of thyroxine during the period from October through April were greater (p<0.05) in cycling versus anestrous mares. However, it remains to be determined whether continuation of estrous cycles during the nonbreeding season and elevated concentrations of thyroxine are causally related.