Isolation of Salmonella Enteritidis phage type 21b from a Eurasian eagle-owl (Bubo bubo)

A case of fatal salmonellosis in a Eurasian eagle-owl (Bubo bubo) from Bursa Province (northwestern Turkey) is described. The organs of the bird were examined histopathologically and microbiologically. Macroscopic and microscopic findings were consistent with a Salmonella infection. Salmonella enterica subspecies enterica serovar Enteritidis (S. Enteritidis) phage type (PT) 21b was isolated from the liver and spleen in pure culture and from the intestine. The isolate was susceptible to amoxycillin/clavulanic acid, ampicillin, chloramphenicol, gentamicin, kanamycin, tetracycline, and trimethoprim/sulphamethoxazole. This is the first report of an isolation of salmonellae from a wild bird species from Turkey and the first time S. Enteritidis PT21b has been reported from Turkey.     

Yeast mitochondrial calcium uptake: Regulation by polyamines and magnesium ions

Spermine, spermidine, and magnesium ions modulate the kinetic parameters of the Ca²⁺ transport system ofEndomyces magnusii mitochondria. Mg²⁺ at concentrations up to 5 mM partially inhibits Ca²⁺ transport with a half-maximal inhibiting concentration of 0.5 mM. In the presence of 2 mM MgCl₂, theS _0.5 value of the Ca²⁺ transport system increases from 220 to 490 µM, which indicates decreased affinity for the system. Spermine and spermidine exert an activating effect, having half-maximal concentrations of 12 and 50 µM, respectively. In the case of spermine, theS _0.5 value falls to 50–65 µM, which implies an increase in the transport system affinity for Ca²⁺. Both Mg²⁺ and spermine cause a decrease of the Hill coefficient, giving evidence for a smaller degree of cooperativity. Spermine and spermidine enable yeast mitochondria to remove Ca²⁺ from the media completely. In contrast, Mg²⁺ lowers the mitochondrial buffer capacity. When both Mg²⁺ and spermine are present in the medium, their effects on theS _0.5 value and the free extramitochondrial Ca²⁺ concentration are additive. The ability of spermine and Mg²⁺ to regulate yeast mitochondrial Ca²⁺ transport is discussed.     

DjPum, a homologue of Drosophila Pumilio, is essential to planarian stem cell maintenance

As stem cells are rare and difficult to study in vivo in adults, the use of classical models of regeneration to address fundamental aspects of the stem cell biology is emerging. Planarian regeneration, which is based upon totipotent stem cells present in the adult--the so-called neoblasts--provides a unique opportunity to study in vivo the molecular program that defines a stem cell. The choice of a stem cell to self-renew or differentiate involves regulatory molecules that also operate as translational repressors, such as members of PUF proteins. In this study, we identified a homologue of the Drosophila PUF gene Pumilio (DjPum) in the planarian Dugesia japonica, with an expression pattern preferentially restricted to neoblasts. Through RNA interference (RNAi), we demonstrate that gene silencing of DjPum dramatically reduces the number of neoblasts, thus supporting the intriguing hypothesis that stem cell maintenance may be an ancestral function of PUF proteins.     

Physiological significance of estrogens in men--breakthrough in endocrinology

Estradiol (E2) is traditionally recognised as the female sex hormone. It has been believed for 40 years, that E2 didn't exert any influence or caused impairment of the gonadal function in men. The main source of E2 in men is adipose tissue and the brain. E2 is also produced in adrenals, liver, mammary glands, hair and in male gonad. Daily production and the level of E2 in the blood in men are higher than those in postmenopausal women. At the end of the 80-ties we were first reporting that during sexual maturation E2 can be the important hormonal signal for the initiation of spermatogenesis. The traditional view about unimportant or inhibitory role of E2 in male physiology was finally refuted thanks to discovering estrogen receptors in males. In the 90-ties, transgenic mice with the lack of estrogen receptor (ER) or gene encoding enzyme aromatase, that enable the conversion of testosterone into E2, were also produced. Observations of men with inherited mutations of these genes, considerably extended our knowledge about E2 in men in stroma bones formation, inhibition of their growing, lipids metabolism and sexual maturation, the effects that were attributed to testosterone action until today. New data also points at important role of estrogens and ER in the function of the cardio-vascular system and in counteracting coronary disease in men.     

Effects of sex, age, body mass, and capturing method on hematologic values of brown bears in Croatia

Effects of various intrinsic and extrinsic factors on 17 hematologic values from 56 brown bears (Ursus arctos) sampled in Croatia from 1981 to 2005 were evaluated. Differences between female and male bears were detected for number of erythrocytes, sedimentation rate after 30 min, and number of leukocytes and segmented neutrophils. Significant differences between free-living vs. captive and snared vs. not snared bears were detected for the same three parameters: leukocytes, segmented neutrophils, and eosinophils. It was concluded that the physical exertion of bears snared by leg, rather than their free-living status, influenced differences of results among these groups. The obtained mean values are useful reference values for the species.     

CYP1A1, CYP2D6, CYP2E1, NAT2, GSTM1 and GSTT1 polymorphisms or their combinations are associated with the increased risk of the laryngeal squamous cell carcinoma

Polymorphisms in the selected genes controlling carcinogen metabolism (CYP1A1, CYP2D6, CYP2E1, NAT2, GSTM1, GSTT1) considered separately or in different combinations, were investigated for an association with tobacco smoke-associated squamous cell carcinoma (SCC) of the larynx. The case-control study was performed in 289 patients with laryngeal SCC and in 316 cancer-free controls; all were Caucasian males from the same region of Poland and current tobacco smokers. The DNA samples were genotyped using PCR-RFLP and multiplex PCR. The variants' frequencies in both groups were compared; odds ratios and their 95% confidence intervals were calculated by logistic regression analyses. The CYP1A1*1/*4, CYP2D6*4/*4, NAT2*4/*6A genotypes, as well as the CYP1A1*4, CYP2D6*4 and NAT2*4 alleles, were found at significantly higher frequencies in cases than in controls indicating their role as "risk-elevating" factors in laryngeal SCC. Combined genotypes, characterized by the presence of the "risk-elevating" variants at more than one locus, often occurred together with the null variant of the GSTM1 gene and homozygous XPD A/A (Lys751Gln, A35931C) genotype. Furthermore, we identified some "protective" variants, found more frequently in controls than in cases, i.e. the NAT2*6A/*6A and NAT2*5B/*6A genotypes. A distribution of "risk" or "protection" genotypes/alleles seems to be connected with age as an occurrence or risk genes was more frequent in the group of "young" cases (< or = 49 years). Accumulation of certain alleles or genotypes of the CYP1A1, NAT2, GSTM1 and XPD seems to be associated with either increased or decreased risk to develop laryngeal SCC. Therefore, polymorphisms in these genes may play a role in the laryngeal cancer etiology.     

Yeast as a biosensor for antioxidants: simple growth tests employing a Saccharomyces cerevisiae mutant defective in superoxide dismutase

Mutants of Saccharomyces cerevisiae devoid of Cu,Zn-superoxide dismutase are hypersensitive to a range of oxidants, hyperbaric oxygen and hyperosmotic media, show lysine and methionine auxotrophy when grown under the atmosphere of air and have a shortened replicative life span when compared to the wild-type strain. Ascorbate and other antioxidants can ameliorate these defects, which may be a basis of simple tests sensing the presence of antioxidants. In particular, tests of growth on solid medium (colony formation) in the absence of methionine and/or lysine, or in the presence of 0.8 M NaCl can be useful for detection and semiquantitative estimation of compounds of antioxidant properties. Hypoxic atmosphere was found to increase the sensitivity of detection of antioxidants. The test of abolishment of lysine auxotrophy showed a concentration dependence of the antioxidant effects of cysteine and N-acetylcysteine which, however, lost their protective action at high concentration, in contrast to glutathione which was effective also at higher concentrations.     

Genetic study of familial cases of Alzheimer's disease

A small number (1-5%) of Alzheimer's disease (AD) cases associated with the early-onset form of the disease (EOAD) appears to be transmitted as a pure genetic, autosomal dominant trait. To date, three genes responsible for familial EOAD have been identified in the human genome: amyloid precursor protein (APP), presenilin 1 (PS1), and presenilin 2 (PS2). Mutations in these genes account for a significant fraction (18 to 50%) of familial cases of early onset AD. The mutations affect APP processing causing increased production of the toxic Abeta42 peptide. According to the "amyloid cascade hypothesis", aggregation of the Abeta42 peptide in brain is a primary event in AD pathogenesis. In our study of twenty AD patients with a positive family history of dementia, 15% (3 of 20) of the cases could be explained by coding sequence mutations in the PS1 gene. Although a frequency of PS1 mutations is less than 2% in the whole population of AD patients, their detection has a significant diagnostic value for both genetic counseling and treatment in families with AD.