Efficacy of animal anti-fertility compounds against sea lamprey (Petromyzon marinus) spermatozoa

Sterile-male-release technique is currently used to control the sea lamprey (Petromyzon marinus) population in the Great Lakes. The chemosterilant (bisazir) used in this program is extremely hazardous; special safety measures are necessary when handling this chemical. Therefore, replacement of bisazir with safer agents is desirable. In this study, we examined the effects of low-toxicity compounds with previously described spermicidal activity (mainly against mammalian sperm) on motility and fertilizing ability of sea lamprey spermatozoa. Nonoxynol-9, benzalkonium chloride, zinc acetate, cupric chloride, cysteamine, tannic acid and propranolol were able to inhibit both sperm motility and fertilizing ability. Effective concentrations of these spermicides ranged from 0.15 to 1%. Therefore, they can be potentially used in further study directed at in vivo sterilization of male sea lampreys.     

Selenium supplementation on plasma glutathione peroxidase activity in patients with end-stage chronic renal failure

Patients with chronic renal failure (CRF) usually have a lower than healthy level of selenium (Se) in whole blood and plasma. Plasma glutathione peroxidase (GSH-Px) is synthesized mostly in the kidney. In CRF patients, activity of this enzyme is significantly reduced and its reduction increases with the progress of the disease. The aim of the study was to evaluate the effect of Se supplementation to CRF patients at various stages of the disease on Se concentration in blood components and on plasma GSH-Px activity. The study group comprised 53 CRF patients at various stages of the disease supplemented with Se (200 μg/d for 3 mo as Se-enriched yeast, containing about 70% l-selenomethionine [SeMet]). The control group consisted of 20 healthy subjects. The Se concentration in blood components was measured spectrofluorometrically with 2,3-diaminonaphthalene as a complexing reagent. GSH-Px activity in red cell hemolysates and plasma was assayed by the coupled method with tert-butyl hydroperoxide as a substrate. The Se concentration in whole blood and plasma of CRF patients is significantly lower as compared with healthy subjects, but similar at all stages of the disease. In the patients’ plasma, total protein and albumin levels are also significantly lower than in healthy subjects. Plasma GSH-Px activity in patients is extremely low, and contrary to Se concentration, it decreases linearly with the increasing stage of the illness. Se-supplied patients show an increased Se concentration in all blood components and at all disease stages, whereas plasma GSH-Px activity is enhanced only at the incipient stage of the disease. Se supply has no effect on plasma GSH-Px activity in uremic patients at the end stage of the disease. Total plasma protein and albumin levels did not change after Se supplementation. Our data seem to show that in patients with CRF lower total protein and albumin levels in plasma may be the chief cause of the low blood and plasma Se concentrations. GSH-Px activity decreases along with the kidney impairment. At the end stage of the disease, Se supplementation in the form of Se-enriched yeast has no effect on the increase in plasma GSH-Px activity.     

Degradation of acrylic copolymers by white-rot fungi

Various water-soluble homopolymers and copolymers of acrylamide (AAm) and acrylic acid (AA) which contained phenolic sites, such as guaiacol, lignin sulfonate (LS) and 3,4-dihydroxybenzoic acid (3,4-DHBA), were tested with regard to their degradability by white-rot fungi. Compared with Phanerochaete chrysosporium, Pleurotus ostreatus caused a significantly higher decrease in the average molecular weight (_w) of most of the copolymers and the homopolymer under the applied culture conditions. However, the _w of poly(guaiacol/AAm) increased significantly during incubation with Pl ostreatus. P. chrysosporium was able to reduce only the _w of the poly(LS/AA) to a significant degree and not that of the other polymers. The mineralization rate of AAm and AA copolymers and terpolymers of AAm, AA and phenolics (LS, 3,4-DHBA, guiacol), which were tested with P. ostreatus and Trametes versicolor, turned out to be low (0.8–3.2%). While the rates of mineralization were similar among all polymers, the decrease in radioactivity from the culture media was higher with the terpolymers bearing phenolic sites. UV spectra of the culture media revealed that the phenolic sites in the terpolymers were significantly degraded by both fungi. Obviously, the degradation of phenolics within the polymer chain caused a higher decrease in _w but did not significantly increase the mineralization rate.     

Amplification of evoked potentials recorded from mouse hippocampal slices by very low repetition rate pulsed magnetic fields

The influence of low repetition rate pulsed magnetic fields (LRMF) on the evoked potential (population spike) recorded from mouse hippocampal slices was investigated. LRMF were applied according to two protocols. In protocol A, LRMF applied with a constant strength (15 mT) and frequency ranging from 0.03 to 0.5 Hz resulted in an amplification of the potential. Although the frequency of 0.16 Hz was the most effective, enhancing the population spike by over 280%, it also caused an increase in spontaneous activity, seizures, and cessation of neuronal activity in 50% of the slices. In protocol B, LRMF were applied with a variable intensity (9-15 mT) and in cycles of different duration ranging from 5 to 20 min. While an increase in the amplitude of the population spike was observed in all slices exposed to LRMF applied according to protocol B, the longest exposure was the most effective. Neither seizures nor an increase in the spontaneous activity were observed in this group of the slices. These results support and extend our previous data and characterize further the relation between the pattern of applied magnetic fields and their influence on the nervous system.     

Non-peptide oxytocin agonists

A library of compounds targeted to the vasopressin/oxytocin family of receptors was screened for activity at a cloned human oxytocin receptor using a reporter gene assay. Potency and selectivity were optimised to afford compound 39, EC50 = 33 nM. This series of compounds represents the first disclosed, non-peptide, low molecular weight agonists of the hormone oxytocin (OT).     

Characteristics of arylsulfatase in Russian sturgeon (Acipenser gueldenstaedti) semen

Spermatozoa of sturgeons (Acipenseriformes), unlike teleosts, possess an acrosome. This paper provides data concerning biochemical characteristics of arylsulfatase (AS), an acrosomal enzyme, found in Russian sturgeon spermatozoa and seminal plasma. The enzymes were purified by a four-step procedure, using n-butanol extraction, ion-exchange chromatography repeated twice and gel filtration. High purity of our enzymes was confirmed by silver staining electrophoresis and an immunological experiment. Kinetic parameters indicated that the purified enzymes belong to arylsulfatase type A. Similarity of the seminal plasma arylsulfatase to the spermatozoan enzyme showed us that arylsulfatase from seminal plasma might originate from damaged spermatozoa. The possible physiological consequences of the presence of arylsulfatase in Russian sturgeon semen are discussed.     

Clumping factor A-mediated virulence during Staphylococcus aureus infection is retained despite fibrinogen depletion

Clumping factor A (ClfA), a fibrinogen-binding protein expressed on the Staphylococcus aureus cell surface, has previously been shown to act as a virulence factor in experimental septic arthritis. Although the interaction between ClfA and fibrinogen is assumed to be of importance for the virulence of S. aureus, this has not been demonstrated in any in vivo model of infection. Therefore, the objective of this study was to investigate the contribution of this interaction to ClfA-mediated virulence in murine S. aureus-induced arthritis. Ancrod, a serine protease with thrombin-like activity, was used to induce in vivo depletion of fibrinogen in mice. Ancrod treatment significantly aggravated septic arthritis following inoculation with a ClfA-expressing strain (Newman) compared to control treatment. Also, ancrod treatment tended to enhance the arthritis induced by a clfA mutant strain (DU5876), indicating that fibrinogen depletion exacerbates septic arthritis in a ClfA-independent manner. Most importantly, the ClfA-expressing strain was much more arthritogenic than the isogenic clfA mutant, following inoculation of fibrinogen-depleted mice. This finding indicates that the interaction between ClfA and free fibrinogen is not required for ClfA-mediated functions contributing to S. aureus virulence. It is conceivable that ClfA contributes to the virulence of S. aureus through interactions with other host ligands than fibrinogen.     

Crystal structure of the hypothetical protein TA1238 from Thermoplasma acidophilum: a new type of helical super-bundle

The crystal structure of the hypothetical protein TA1238 from Thermoplasma acidophilum was solved with multiple-wavelength anomalous diffraction and refined at 2.0 A resolution. The molecule consists of a typical four-helix antiparallel bundle with overhand connection. However, its oligomerization into a trimer leads to a coiled "super-helix" which is novel for such bundles. Its central feature, a six-stranded coiled coil, is also novel for proteins. TA1238 does not have strong sequence homologues in databases, but shows strong structural similarity with some proteins in the Protein Data Bank. The function could not be inferred from the sequence but the structure, with some rearrangement, bears some resemblance to the active site region of cobalamin adenosyltransferase (TA1434). Specifically, TA1238 retains Arg104, which is structurally equivalent to functionally critical Arg119 of TA1434. For such conformational change, the overhand connection of TA1238 might need to be involved in a gating mechanism that might be modulated by ligands and/or by interactions with the physiological partners. This allowed us to hypothesize that TA1238 could be involved in cobalamin biosyntheses.