Enzymatic/biochemical analysis of Actinomyces with commercial test kits with an emphasis on newly described species

In clinical microbiology laboratories, the identification of Actinomyces-like bacteria can be very laborious and problematic. In the present study, we focused on reactivity patterns of 4 commercial test kits, RapID ANA II, RapID 32A, RapID CB Plus, and BBL Crystal ANR ID, that could be used for rapid preliminary identification of Actinomyces isolates belonging to newly described Actinomyces and closely related species. Out of the 54 strains tested, 25 strains (46%) were correctly identified to the genus/group level by BBL Crystal ANR ID system, 16 strains (30%) by RapID 32 A, 11 strains (20%) by RapID CB Plus, and 7 strains (13%) by RapID ANA II. The main problems with these kits were due to occasional weak enzymatic and sugar fermentation reactions. In conclusion, chromogenic substrate sensitivity and specificity need to be enhanced in order to improve the reliability of the test results of these kits, and the present database updated in order to more precisely identify newly described Actinomyces and closely related species.     

Effects of dietary genistein on mouse reproduction, postnatal development and weight-regulation

Genistein is a soy isoflavone with estrogenic activity present in plant-based food items and health foods and used as an alternative therapy for cancer, cardiovascular diseases, menopausal symptoms and osteoporosis. The aim of this study was to investigate the effects of dietary genistein (8 mg/kg body weight/day) on the reproduction, postnatal development and weight regulation of mice across two generations. Genistein treatment decreased the relative food consumption in females at 1 and 5 weeks and in males at 5 weeks. In female pups, the relative kidney weights were lower due to genistein exposure. Furthermore, the genistein-exposed male pups had greater relative prostate and seminal vesicles weights than the control pups. In adult males, genistein treatment decreased the plasma estradiol concentrations and increased levels of the plasma HDL cholesterol and triglycerides in adult females. Also the plasma ghrelin concentrations decreased in the adult genistein treated female mice. Genistein increased the plasma triglyceride levels of male pups and triiodothyronine levels of female pups. Reproduction of the mice was not endangered due to genistein exposure.     

Urokinase-type plasminogen activator and its inhibitor secreted by cultured human monocyte-macrophages

Human blood monocytes in culture differentiate to macrophagelike cells within 1 week. Coinciding with this morphological transition the cells started releasing increasing amounts of the serine proteinase plasminogen activator (PA; Mr 56,000) of the urokinase (u-PA) type and the proteinase inhibitor alpha-2-macroglobulin (alpha 2M). Unlike the cell-associated PA activity, which was also readily detected in fresh monocytes, the activity secreted into the serum-free culture medium could be measured only after treatment of the samples with sodium dodecyl sulphate. Heat or acid treatment of the medium was not sufficient to reveal the PA activity, suggesting that, apart from alpha 2M, another PA-inhibiting substance was present in the culture medium. The inhibitor (Mr 65,000) was found to be synthesized by macrophages and specifically inhibited u-PA activity but not tissue-type PA (t-PA) or plasmin activity. Dexamethasone decreased the secretion of PA by differentiated macrophages without affecting the production of alpha 2M or the PA inhibitor. Dexamethasone also inhibited the morphological differentiation of the cells when added to the monocyte-phase cells.     

Characterization of the striatal dopaminergic neurotransmission in MEN2B mice with elevated cerebral tissue dopamine

The Ret receptor tyrosine kinase is the common signaling receptor for the glial cell line-derived neurotrophic factor (GDNF) family ligands. The Met918Thr mutation leads to constitutive activation of Ret and is responsible for dominantly inherited cancer syndrome MEN2B. Previously, we found that the mice carrying the mutation (MEN2B mice) have profoundly increased tissue dopamine (DA) concentrations in the striatum as well as increased striatal levels of tyrosine hydroxylase (TH) and dopamine transporter. The aim of this study was to characterize the striatal dopaminergic neurotransmission in MEN2B mice and to clarify the mechanisms by which they compensate their over-production of DA. We found that tyrosine hydroxylase activity and DA synthesis are increased in MEN2B mice. Augmented effects of α-methyl-para-tyrosine (αMT, an inhibitor of TH) and tetrabenazine (VMAT2 blocker) on DA levels suggest that also storage of DA is increased in MEN2B mice. There was no difference in the basal extracellular DA concentrations or potassium-evoked DA release between the genotypes. The effects of cocaine and haloperidol were also similar between the genotypes as assessed by in vivo microdialysis. However, with in vivo voltammetry we found increase in stimulated DA release in MEN2B mice and detailed analysis of DA overflow showed that uptake of DA was also enhanced in MEN2B mice. Thus, our data show that enhanced synthesis of DA leading to increased storage and releasable pools in pre-synaptic terminals in MEN2B mice apparently also leads to increased DA release, which in turn is compensated by higher dopamine transporter activity.     

Stress,immunocompetence and leukocyte profiles of pied flycatchers in relation to brood size manipulation

The two main trade-offs considered determining reproductive patterns in iteroparous organisms are the one between current and future reproduction, and the one between the number and quality of offspring. Recently, it has been suggested that these trade-offs may be mediated by stress-induced reduction in immunocompetence. To test the hypothesis that stress reduces immune function, we investigated the effects of brood size manipulation on stress hormone levels, leukocyte profiles and immune responses against challenge with novel antigens in nestling and parent male pied flycatchers ( Ficedula hypoleuca). In male parents, heterophil (H) and lymphocyte (L) numbers, as well as H/L ratio increased with experimentally enlarged brood size, and corticosterone levels tended to do so, indicating that high parental work load altered their stress level and physiological state. Despite this, we found no effects on humoral immune responsiveness, measured as antibody production against diphtheria-tetanus vaccine. In nestlings, heterophil numbers and H/L ratio increased in enlarged broods, whereas T-cell-mediated immune responsiveness, measured against phytohemagglutinin (PHA), decreased in enlarged broods. The results support the view that growth-stress-induced immunosuppression may be an important physiological pathway mediating the trade-off between the number and viability of offspring. The difference in the observed immune-related responses between nestlings and males may be because we measured different aspects of the immune system (cellular vs humoral). However, it may also be a result of males lowering their own costs by feeding less, (and their mate possibly compensate by feeding more), whereas nestlings cannot escape the costs of increased intra-brood competition.     

Endocrinologic adaptations to wintertime fasting in the male American mink (Mustela vison)

The aim of this study was to investigate the endocrine response to wintertime starvation in the male American mink (Mustela vison) fasted for 16 hrs, 2 days, 3 days, 5 days, or 7 days (n =10 per group). After 2 days of fasting, the plasma leptin concentrations decreased, along with the triiodothyronine, testosterone, and progesterone levels, and the blood monocyte counts. Leptin also seems to trigger the response to fasting in mustelids by inducing immunosuppression and downregulation of the reproductive and thyroid axes. The dramatic increase in the peptide YY concentrations after 3 days of fasting may be required to suppress gastrointestinal processes during food scarcity. The plasma insulin levels decreased, and those of glucagon increased after 5 days of fasting in association with efficient glucose sparing and lipid mobilization. Body energy stores cannot be wasted for growth during nutritional scarcity and, thus, the growth hormone levels of the minks decreased after 5 days of fasting. The plasma noradrenaline and cortisol concentrations also decreased after 3 and 7 days without food, respectively. The plasma ghrelin, adiponectin, resistin, thyroxine, adrenaline, or estradiol levels did not respond to fasting. The endocrine response to food deprivation is remarkably similar in divergent mammalian orders, indicating that the hormonal signals enhancing survival during nutritional scarcity must be evolutionarily old and well conserved.     

Hyperthermia and increased physical activity in the fasting American mink Mustela Vison

The aim of this study was to investigate the thermoregulatory adaptations to fasting in a medium-sized mustelid with a high metabolic rate and energetic requirements. Sixteen farm-bred female American minks, Mustela vison, were divided into a fed control group and an experimental group fasted for 5 days. The deep body temperature (T(b)) of the minks was registered at 10 min intervals with intraabdominal thermosensitive loggers and the locomotor activity was videotaped continuously for 5 days during the fasting procedure. The T(b) of the fasted animals increased during the first day of fasting and decreased during the second day. After 3-4 days of fasting, the levels of physical activity and T(b) of the fasted minks increased above the levels of the fed animals. Significant increases in these parameters were observed at the beginning of the working day on the farm, during the feeding of the fed animals and around midnight. It is concluded that the mink differs from previously studied homeotherms in thermoregulatory and behavioral responses to fasting probably due to its high energy requirements and predatory success.     

Decreased Bone Mineral Density in Adults Born with Very Low Birth Weight: A Cohort Study

Background

Very-low-birth-weight (VLBW, <1,500 g) infants have compromised bone mass accrual during childhood, but it is unclear whether this results in subnormal peak bone mass and increased risk of impaired skeletal health in adulthood. We hypothesized that VLBW is associated with reduced bone mineral density (BMD) in adulthood.

Methods and Findings

The Helsinki Study of Very Low Birth Weight Adults is a multidisciplinary cohort study representative of all VLBW births within the larger Helsinki area from 1978 to 1985. This study evaluated skeletal health in 144 such participants (all born preterm, mean gestational age 29.3 wk, birth weight 1,127 g, birth weight Z score 1.3), and in 139 comparison participants born at term, matched for sex, age, and birth hospital. BMD was measured by dual energy X-ray absorptiometry at age 18.5 to 27.1 y. Adults born with VLBW had, in comparison to participants born at term, a 0.51-unit (95% confidence interval [CI] 0.28–0.75) lower lumbar spine Z score and a 0.56-unit (95% CI 0.34–0.78) lower femoral neck Z score for areal BMD. These differences remained statistically significant after adjustment for the VLBW adults'' shorter height and lower self-reported exercise intensity.

Conclusions

Young adults born with VLBW, when studied close to the age of peak bone mass, have significantly lower BMD than do their term-born peers. This suggests that compromised childhood bone mass accrual in preterm VLBW children translates into increased risk for osteoporosis in adulthood, warranting vigilance in osteoporosis prevention. Please see later in the article for the Editors'' Summary     

JC virus strains indigenous to northeastern Siberians and Canadian Inuits are unique but evolutionally related to those distributed throughout Europe and Mediterranean areas

Human polyomavirus JC virus (JCV) isolates around the world are classified into more than 10 geographically distinct genotypes (designated as subtypes). Evolutionary relationships among JCV subtypes were recently examined, and the following pattern of JCV evolution was indicated. The ancestral JCV first divided into three superclusters, designated Types A, B, and C. A split in Type A generated two subtypes, EU-a and -b, containing mainly European and Mediterranean isolates. The split in Type B generated Af 2 (the major African subtype), Bl-c (a minor European subtype), and various Asian subtypes. Type C generated a single subtype (Afl), consisting of isolates derived from western Africa. In this study, JCV isolates prevalent among northeastern Siberians and Canadian Inuits were evaluated in the context of the above-described pattern of JCV evolution. The Siberian/Arctic JCV isolates were classified as belonging mainly to Type A, based on the result of a preliminary phylogenetic analysis. We then examined, using the whole-genome approach, the phylogenetic relationships among worldwide Type A isolates. In neighbor-joining and maximum-likelihood analyses, Type A JCVs worldwide consistently diverged into three subtypes, EU-a, -b, and -c, with high bootstrap probabilities. EU-c was constructed only by northeastern Siberian isolates, derived mainly from Nanais living in the lower Amur River region, and was shown to have been generated by the first split in Type A. Most Siberian/Arctic isolates derived from Chukchis, Koryaks, and Canadian Inuits formed a distinct cluster within the EU-a subtype, with a high bootstrap probability. Based on the present findings, we discuss ancient human migrations, accompanied by Type A JCVs, across Asia and to Arctic areas of North America.