The mitochondrial and nuclear genetic structure of Myotis capaccinii (Chiroptera: Vespertilionidae) in the Eurasian transition, and its taxonomic implications

Allopatric isolation in glacial refugia has caused differentiation and speciation in many taxa globally. In this study, we investigated the nuclear and mitochondrial genetic differentiation of the long fingered bat, Myotis capaccinii during the ice ages in south-eastern Europe and Anatolia. The mitochondrial DNA (mtDNA) analyses indicated a suture zone similar to those recorded in other animal species, including bats, suggesting the association of more than one refugium with the region. Contrary to most of the other species where a suture zone was seen in Anatolia, for M. capaccinii the geographical location of the genetic break was in south-eastern Europe. This mitochondrial differentiation was not reflected in the nuclear microsatellites, however, suggesting that the lack of contact during the ice ages did not result in reproductive isolation. Hence taxonomically, the two mitochondrial clades cannot be treated as separate species.     

Immunohistochemistry of thyroid hormones as a functional parameter in thyroid pathology

The authors study by means of immunoperoxidase method the pattern of thyroglobulin, triiodothyronine and thyroxine distribution in 58 cases of thyroid disorders: 15 euthyroid goiters, 10 Graves' disease, 7 Hashimoto's thyroiditis, 11 folliculo-papillary carcinomas (6 primary tumors and 5 lymph node metastases), 8 follicular carcinomas, 4 anaplastic carcinomas and 3 medullary carcinomas. Thyroglobulin, triiodothyronine and thyroxine were present in most of the thyroid disorders, excepting anaplastic and medullary carcinomas. Thyroglobulin and thyroxine were localized both in the follicular epithelium and in the colloid, whereas triiodothyronine was present especially in the follicular cells. The thyroid hormones distribution in benign lesions is rather similar. In carcinomas, the pattern of thyroglobulin, triiodothyronine and thyroxine is more heterogeneous, but generally the triiodothyronine distribution is similar to that of thyroglobulin. In some carcinomas, triiodothyronine and thyroxine showed a weak or negative immunostaining. The immunoperoxidase method is a valuable tool in the study of functional disturbances in the thyroid pathology and in the diagnosis of thyroid carcinoma metastases as well. Positive thyroid hormones staining clearly indicates the thyroid origin of metastases.     

Turnover of plant lineages shapes herbivore phylogenetic beta diversity along ecological gradients

Understanding drivers of biodiversity patterns is of prime importance in this era of severe environmental crisis. More diverse plant communities have been postulated to represent a larger functional trait‐space, more likely to sustain a diverse assembly of herbivore species. Here, we expand this hypothesis to integrate environmental, functional and phylogenetic variation of plant communities as factors explaining the diversity of lepidopteran assemblages along elevation gradients in the Swiss Western Alps. According to expectations, we found that the association between butterflies and their host plants is highly phylogenetically structured. Multiple regression analyses showed the combined effect of climate, functional traits and phylogenetic diversity in structuring butterfly communities. Furthermore, we provide the first evidence that plant phylogenetic beta diversity is the major driver explaining butterfly phylogenetic beta diversity. Along ecological gradients, the bottom up control of herbivore diversity is thus driven by phylogenetically structured turnover of plant traits as well as environmental variables.     

The plasma membrane of yeast protoplasts exposed to hypotonicity becomes porous but does not disintegrate in the presence of protons or polyvalent cations

Protoplasts of Saccharomyces cerevisiae swelled, lysed and disintegrated when exposed to hypotonic solutions at neutral pH. At pH 4.5 or lower the hypotonically treated protoplasts did not disintegrate and they retained their intracellular proteins, nucleic acids and nucleotides. However, they became leaky for K+ and Ca2+, indicating that pores had been created in the surface membrane, relaxing the osmotic stress. Upon readjustment of pH to neutral, the hypotonically treated protoplasts released the intracellular content and disintegrated. Also, at low pH, protoplasts did not swell in isotonic ammonium acetate and were refractory to the permeabilizing effect of nystatin and to lysis with low concentrations of detergents. Protoplasts were similarly protected against lysis and disintegration by hypotonic treatment or by detergents, even at neutral pH, if the incubation media contained polyvalent cations, especially Zn2+, La3+, spermine, and Ca2+ chelated with EDTA. The protoplasts exposed to hypotonic stress at low pH did not respire and could not regenerate into viable cells. Effects of H+ and polyvalent cations on intramembrane forces acting between molecules of membrane phospholipids are considered along with possible changes in interactions between membrane proteins.     

Model-based relationship between physicochemical properties and inhibitory potency of alkylating 2-furylethylenes on yeast glycolysis

Inhibitory effects of 35 2-furylethylenes, non-specific alkylating agents, on glycolysis in a respiratory mutant of Saccharomyces cerevisiae were correlated with their 1-octanol/water partition coefficients and the rate constants for reaction with 2-mercaptoacetic acid using physiologically based models. The simplest model explaining the data satisfactorily consists of two-step drug-receptor interaction involving reversible formation of a structurally non-specific non-covalent complex stabilized later covalently. The concentration of the free drug in the receptor surroundings was related to its initial concentration in external medium via a simple form of a disposition function constructed on the basis of time hierarchy of passive membrane transport, non-covalent binding to cell constituents and metabolic inactivation of the drug.     

Characteristics of the neuronal reaction of the substantia nigra to nociceptive stimulation

The nature of neurone response of substance nigra (SN) to nociceptive stimulation of the cat's peroneal nerve has been studied. The recording of neurone SN firing rate revealed that the majority (71.0%) of the SN neurones responded to the nociceptive repetitive stimulation of the peroneal nerve. But the thresholds of nociceptive activation in SN neurones turned to be very high. As a result of it the number of SN neurones responding to repetitive peroneal stimulation was twice as many as the number of cells responding to single stimulation of the nerve. The intravenous injection of naloxone in dose 1.0 mg/kg changed both excitatory and inhibitory responses in majority (71.4%) of SN neurones responding to repetitive peroneal stimulation. Naloxone did not modify the firing rate of neurones nonresponsive to nociception.     

Adherence to epithelial cells and ultrastructure of fosfomycin-resistant mutants of group A streptococci

Adherence of three strains of group A streptococci and their fosfomycin-resistant mutants to HEp-2 tissue culture cells was compared with some cell-surface characteristics, i.e. ultrastructure and hydrophobicity. Among Fosr mutants, both well-adhering and weakly adhering mutants were found. Clonal analysis of the mutants proved their greater stability in the adherence. Well-adhering parent strains of streptococci and Fosr mutants exhibited surface fibrillae in contrast to weakly adhering Fosr mutants which were devoid of fibrillae or contined fibrillae of lower electron density. Decrease of adherence of Fosr mutants of two strains was accompanied by a decrease of their hydrophobicity.     

The adhesin structures involved in the adherence of group B streptococci to human vaginal cells

The adherence of group B streptococci (GBS) of serotypes Ia, II and III to human vaginal cells was studied in vitro. The adherence was not dependent on the viability of bacteria; killing of GBS by UV irradiation or glutaraldehyde treatment did not inhibit the adherence. Killing of GBS by heating to 56 degrees C for 1 h led to a pronounced decrease of adherence, demonstrating the thermosensitivity of the GBS structures involved. The protein nature of these structures was proved by a significant reduction of adherence after pretreatment of GBS with trypsin or pepsin. Pretreatment of GBS with sialidase had no influence on the adherence. Such a pretreatment of vaginal cells caused an increase of adherence showing that the receptors on epithelial cells may be partly masked by sialic acid.