Semen cryopreservation in golden‐headed lion tamarin,Leontopithecus chrysomelas

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden‐headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden‐headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm–egg‐binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short‐term measure for the conservation of golden‐headed lion tamarins.     

Bemerkenswerte Pflanzenfunde aus Bosnien und der Herzegowina

Zusammenfassung In der vorliegenden Arbeit wurden Pflanzenarten besprochen, die selten oder neu für das Gebiet Bosniens und der Herzegowina, und meist von allgemeinem pflanzengeographischem Interesse sind. Einige dieser Funde wurden auf Dolomit oder Serpentinunterlage festgestellt, von welchen auch einige neue Sippen beschrieben wurden.     

Effects of DNase production, plasmid size, and restriction barriers on transformation of Vibrio cholerae by electroporation and osmotic shock

Attempts to transform wild type strains of V. cholerae with plasmid DNA by traditional osmotic shock methods were not successful. A mutant of V. cholerae that was deficient in extracellular DNase was transformed with plasmid DNA by osmotic shock, demonstrating directly that extracellular DNase is a major barrier to transformation of V. cholerae. Transformation of wild type and DNase-negative strains of V. cholerae was accomplished by electroporation. Efficiency of transformation by electroporation increased with field strength, decreased with plasmid size, and was relatively insensitive to changes in the electrolyte composition of the buffer as long as isotonic sucrose was present. Host-controlled modification/restriction systems also affected transformation efficiency in V. cholerae.     

The daily variations of airborne fungal spores in Mexico City

The daily and seasonal distribution of airborne fungal particles was recorded in a high altitude tropical zone. Sampling was carried out in the southern part of Mexico City. An Andersen air sampler was used over a period of six months. Ten minutes sampling for each set of plates was done at fixed schedule: 07:30, 14:00 and 19:00 hours. The sampler was placed 10 m above the ground. Daily variation was found to be associated with the season, weather and atmospheric stability. The highest value of mold counts (3195 CFU m⁻³) was recorded in the evening on October, a transitional month between the rainy and the dry seasons, the lowest (45 CFU m⁻³) at noon during the rainy season. Mold counts were significantly correlated with temperature, having negative signs both in the morning and at noon, and being positive in the evening. The abundance of only three genera was recorded.Cladosporium, was isolated more frequently, and its abundance at 14:00 h was of 38%;Alternaria represented 4.0%, at 14:00 h, andAspergillus 3.0% at 7:30 h. Fifteen species belonging to the latter genera were identified and most of them are considered as opportunistic molds of clinical significance.     

Isolation of Thy-1 caps and analysis of their phospholipid composition in mouse T-lymphoma cells

In this study we have used a density perturbation method to isolate anti-Thy-1 antibody-induced Thy-1 caps from mouse T-lymphoma cells in the absence of detergents, and then compared the phospholipid composit on of these capped membranes with that of uncapped membranes. Initial phospholipid analysis by two-dimensional thin layer chromatography (2-D TLC) reveals a significant increase in the amount of ³²P-labeled phosphatidylcholine in the Thy-1 capped membrane. In contrast, no significant changes are observed in the labeling of phosphatidylserine, phosphatidylethanolamine, or the sphingomyelins. Therefore, it is suggested that phosphatidylcholine may be involved in the organization and/or regulation of Thy-1 antigen redistribution. The composition of phosphoinositide in uncapped and capped membranes was analysed separately using one-dimensional thin layer chromatography (1-D TLC) to resolve phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP), and phosphatidylinositol 4, 5-bisphosphate (PIP₂) from all other phospholipids. This analysis reveals a significant reduction in levels of PIP and PIP₂, but not PI, in Thy-1 caps. Through the use of ion exchange column chromatography, we have found an increased production of all three species of inositol phosphates during anti-Thy-1 antibody-induced capping. Inositol 1, 4, 5 -triphosphate (IP₃) shows the most significant increase, compared to the much smaller increases in inositol 4, 5-bisphosphate (IP₂) and inositol monophosphate (IP). These results suggest that the binding of anti-Thy-1 antibody to Thy-1 antigen activates phospholipase C which, in turn, initiates polyphosphoinositide turnover and IP₃ production. It is proposed that these observed effects are the result of early signal transducing events which are prerequisite steps in Thy-1 receptor cap formation.     

Phosphatidylethanolamine methyltransferase activity in chick liver microsomes

The synthesis of phosphatidylcholine from phosphatidylethanolamine is carried out by chick liver microsomes (Gallus domesticus). Different concentrations of PE, NPE and NNPE were used as exogenous substrates. Saturation of the S-adenosylmethionine has been found for the three different reactions with or without exogenous substrate. Kinetic parameters have been determined for this enzyme system in chick liver microsomes. The three methyl reactions had a similar pH profile with an optimum at pH = 8. Divalent ions such as Ca2+ or Mg2+ did not stimulate the enzyme activity. The results suggest that the synthesis of phosphatidylcholine from phosphatidylethanolamine by chick liver microsomes exhibits a kinetic pattern with different aspects than that described for other animal or human preparations.     

Effects of Tween 80 and Freon 113 on Measles Virus

Measles vaccines were prepared from the same virus fluids by inactivation with formaldehyde or by extraction with ether, ethyl acetate, or Freon 113 in the presence of Tween 80. Tests of antigenic potency, based on antibody levels in guinea pigs, showed that the formaldehyde-inactivated vaccines were more potent than the solvent-inactivated preparations and had the additional advantage of long shelf life. Residual Tween 80 in the solvent-extracted vaccines resulted in marked loss of immunogenic potency without significant loss of hemagglutinating activity. Neither extraction with organic solvents nor exhaustive dialysis efficiently removed Tween 80 from aqueous solutions.