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.     

Use of ATP bioluminescence measurements for the estimation of biomass during biological humification

Summary The development of the microflora during the humification of grape pulp has been investigated by the determination of ATP using the bioluminescence technique. Several extraction methods were tested including the use of dimethylsulphoxide, trichloroacetic acid, grinding and ultrasonification. Dimethylsulphoxide and ultrasonification for 15 sec appeared to be the most effective. The ATP extract was stabilized when it was mixed with 0.75 mM glycine, 4.4 mM Mg-EDTA, pH 7.5 and frozen. The relative error of the ATP assay by bioluminescence did not exceed 6.5%. This method allowed us to show that at least five distinct reproducible microbial phases exist during grape pulp humification. These results show that the microbial biomass changes noticeably and at distinct times during composting.     

Interaction of ethanol with opiate receptors

Addition of ethanol to rat brain homogenate containing opiate receptors inhibits at a concentration of 50 mM the stereospecific binding of 3H-naloxone at 37 degrees C but not at 0 degree C, with the ID50 being 462 mM under these conditions. The temperature-dependent inhibition of the ligand binding suggests that ethanol does not compete with naloxone for specific binding sites of opiate receptors and changes the structure of lipids in biological membranes. Scatchard's analysis has demonstrated that apart from a decrease in the number of highly affinity binding sites of 3H-naloxone, the total amount of the binding sites remains unchanged both in the presence and absence of ethanol and constitutes 453 and 549 fmol/mg protein. It is assumed that ethanol might interconvert highly and low-affinity binding sites. Analysis of the effect of ethanol on 3H-naloxone binding with opiate receptors contained by synaptic membranes obtained from animals with varying predisposition to voluntary alcoholization has shown that ethanol inhibits to a greater degree ligand binding with membranes obtained from rats predisposed to alcoholization. The possibility of the involvement of receptors in the biochemical mechanisms by which the initial alcoholic motivation is effected is under discussion.     

Effect of adrenaline on kidney lysosome function in rats during prolonged soft tissue crushing

The total and unsedimentable activity of acid DNase, RNase, phosphatase and arylsulfatases A and B was examined in the rat kidneys during long-term compression of soft tissues in the presence of high excitability of the sympathoadrenal system. Injection of adrenalin to rats with trauma reduced the total activity of DNase, acid phosphatase and arylsulfatases A and B, particularly at the late periods of soft tissue compression, whereas the total activity of acid RNase slightly increased as compared with control. Compression of soft tissues after adrenalin preinjection was accompanied by a substantial rise of unsedimentable activity of the lysosomal enzymes under study in the kidneys. The activity of the enzymes in cytosol progressively ascended as the time of soft tissue injury increased.     

How Accurate are Paleoecological Reconstructions of Early Paleontological and Archaeological Sites?

Paleoecology allows construction of paleoenvironmental models, faunal changes and evolutionary trends of paleontological taxa using modern analogs. However, when linking modern analogs to paleontological taxa in paleoecological reconstruction, differential taxonomic preservation in the fossil record has to be taken into account. Paleontologists have known the biased nature of the fossil record since Efremov’s publication on taphonomy in 1940, yet many ecological models of habitats associated with hominins in paleontological and archaeological sites in Africa and elsewhere barely address the complexity of the fossil record. We use randomly sampled ungulates from modern biomes in a comparative taxonomic abundance to demonstrate how the combination of modern thanatocoenoses and taphocoenoses, when used in reference to habitat-specific biocoenosis, produce better inferences of past habitats in paleontological and archaeological sites than approaches currently used.     

Littoral diatoms as indicators for the eutrophication of shallow lakes

The littoral zone of shallow water bodies in the Czech Republic has been studied quite consistently at several fishponds. The use of algae, especially diatoms, for the monitoring of the state of lotic freshwater also has a long tradition. The main objective of the presented paper is to validate the feasibility of the use of littoral periphyton comunities for the biomonitoring of standing waters. At the investigated sites, littoral periphytic diatoms were studied together with selected enviromental variables (pH, conductivity, nutrients – especially total phosphorus) on three types of natural substrates (epilithon, epiphyton, epipelon). The evaluation of the diatom community was performed on the basis of the checklists of algal indicator species published by authors from the Czech Republic, Austria and the Netherlands. The data were subjected to statistical software NCCS 2000 (GLM Anova and ``Ward's minimum'' variance cluster analysis). Littoral periphytic diatoms appear to be good indicators of the fishpond water quality. The selected substrates show non-significant differences therefore the average values from all substrates were used. The best indicatory system for evaluation of Czech fishponds was van Dam's index.