What is the potential of spread in invasive bryophytes?

Although the number of invasive bryophytes is much lower than that of higher plants, they threaten habitats that are often species rich and of high conservation relevance. Their potential of spread has, however, never been determined. Here, we assess whether the three most invasive bryophyte species shifted their niche during the invasion process and whether the extent of the study area defined to calibrate the model (geographic background, GB) affects model transferability. We then determine whether ecological niche models (ENMs) developed in their native range can be projected in other areas to assess their invasive potential. The macroclimatic niches of Campylopus introflexus, Orthodontium lineare and Lophocolea semiteres were compared in their native range (Southern Hemisphere) and in their invasion range (Northern Hemisphere) using ordination techniques. ENMs from an ensemble model were calibrated in the native range and projected onto the Northern Hemisphere using different GBs. No evidence for niche expansion in the invaded range was found and the species occur in the invaded range under climate conditions that are similar to those in the native range. The performance of the models to predict occurrences in the invaded range increased with the extent of the GB. The potential range of all species included entire regions on continents where they are still absent. The expansion of the investigated species appears to be constrained by climate conditions that are similar to those currently prevailing in their native range, which is consistent with our failure to demonstrate macroclimatic niche shift in the invaded range. The use of large GBs is recommended in such vagile organisms with large, disjunct distributions. The models indicated that invasive bryophyte species might become a threat in central and eastern Europe, North America and eastern Asia if accidentally introduced or naturally dispersed.     

Effect of prostaglandin F2α on anterior pituitary function in man

Five healthy adult men received iv PGF_2α at dosages of 0.05, 0.20 and 2.0 μg/kg/min for 30 min. There were no significant changes in serum FSH, LH or TSH levels. Serum GH and cortisol levels were slightly increased at the highest dosage. These responses were associated with, and presumably a result of, stressful side effects. Thus, PGF_2α cannot be used as a provocative test of pituitary hormone reserve.Prostaglandins (PG's) have recently been implicated in the release of a number of hormones from the anterior pituitary gland. The stimulation of GH release by PG's of the E series from incubated rat pituitary slices has been demonstrated. $\text{In vivo}$ stimulation by PGE₁ of ACTH in rats and of GH release in man has also been shown.The present study was undertaken in order to examine the efficacy of iv administration of PGF_2α as a provocative test of anterior pituitary hormone reserve in man. The responses in circulating levels of gonadotropins, TSH, GH, and cortisol (as an index of ACTH) were measured.     

To Burn or Not to Burn? Effect of Management Strategy on North American Prairie Vegetation for Public Urban Areas in Germany

North American prairie vegetation has been a role model for designing highly attractive plantings for German urban green spaces for the past decade. In combination with gravel mulch top layers on planting sites and non-selective maintenance techniques like mowing or burning, prairie plantings are considered to be cost-effective and low-maintenance. This study was undertaken to assess the impact of different maintenance strategies and especially the necessity of fire management on the development success of ornamental prairie plantings in central Europe. A four factorial split-plot-block design was set up for investigation of different mixtures of prairie species under varying management conditions (mow-only, mowing plus selective weeding, mowing plus weeding and burning) on two differing soil types (in-situ topsoil and in-situ topsoil with a graywacke gravel mulch top layer) over three years. Significant effects of maintenance strategy on mortality rates and vitality were documented for a number of target species, which responded species specifically, either being slightly affected by the burning or thriving on it. Those effects were mostly restricted to topsoil sites. A strong impact on weed species presence and abundance and resulting maintenance times was found on both soil types. On topsoil sites, mow-only treatment resulted in a short-term loss of the original planting due to extensive weed growth. Corresponding gravel mulch sites were generally less colonised and visually dominated by weeds. Differences between weeded and weeded plus burned sites were minor. Unexpectedly, weed species populations were mostly unaffected by the additional burning treatment, while maintenance times and costs increased. No overall benefit of fire management for the establishment of prairie plantings was documented. The most effective management combination proved to be mowing plus regular selective weeding measures on gravel mulched planting sites.     

Effect of carnosine alone or combined with α-tocopherol on hepatic steatosis and oxidative stress in fructose-induced insulin-resistant rats

A diet high in fructose (HFr) induces insulin resistance in animals. Free radicals are involved in the pathogenesis of HFr-induced insulin resistance. Carnosine (CAR) is a dipeptide with antioxidant properties. We investigated the effect of CAR alone or in combination with α-tocopherol (CAR?+?TOC) on HFr-induced insulin-resistant rats. Rats fed with HFr containing 60 % fructose received CAR (2 g/L in drinking water) with/without TOC (200 mg/kg, i.m. twice a week) for 8 weeks. Insulin resistance, serum lipids, inflammation markers, hepatic lipids, lipid peroxides, and glutathione (GSH) levels together with glutathione peroxidase (GSH-Px) and superoxide dismutase 1 (CuZnSOD; SOD1) activities and their protein expressions were measured. Hepatic histopathological examinations were performed. HFr was observed to cause insulin resistance, inflammation and hypertriglyceridemia, and increased triglyceride and lipid peroxide levels in the liver. GSH-Px activity and expression decreased, but GSH levels and SOD1 activity and expression did not alter in HFr rats. Hepatic marker enzyme activities in serum increased and marked macro- and microvesicular steatosis were seen in the liver. CAR treatment did not alter insulin resistance and hypertriglyceridemia, but it decreased steatosis and lipid peroxidation without any change in the antioxidant system of the liver. However, CAR?+?TOC treatment decreased insulin resistance, inflammation, hepatic steatosis, and lipid peroxidation and increased GSH-Px activity and expression in the liver. Our results may indicate that CAR?+?TOC treatment is more effective to decrease HFr-induced insulin resistance, inflammation, hepatic steatosis, and dysfunction and pro-oxidant status in rats than CAR alone.     

Is the Effect of Aerobic Exercise on Cognition a Placebo Effect?

A number of studies and meta-analyses conclude that aerobic fitness (walking) interventions improve cognition. Such interventions typically compare improvements from these interventions to an active control group in which participants engage in non-aerobic activities (typically stretching and toning) for an equivalent amount of time. However, in the absence of a double-blind design, the presence of an active control group does not necessarily control for placebo effects; participants might expect different amounts of improvement for the treatment and control interventions [1]. We conducted a large survey to explore whether people expect greater cognitive benefits from an aerobic exercise intervention compared to a control intervention. If participants expect greater improvement following aerobic exercise, then the benefits of such interventions might be due in part to a placebo effect. In general, expectations did not differ between aerobic and non-aerobic interventions. If anything, some of the results suggest the opposite (e.g., respondents expected the control, non-aerobic intervention to yield bigger memory gains). These results provide the first evidence that cognitive improvements following aerobic fitness training are not due to differential expectations.     

Effect of 2-deoxy-d-Glucose on Aminoacids Metabolism in Rats’ Cerebral Cortex Slices

We studied the effect of different concentrations of 2-deoxy-d-glucose on the l-[U-¹⁴C]leucine, l-[1-¹⁴C]leucine and [1-¹⁴C]glycine metabolism in slices of cerebral cortex of 10-day-old rats. 2-deoxy-d-glucose since 0.5 mM concentration has inhibited significantly the protein synthesis from l-[U-¹⁴C]leucine and from [1-¹⁴C]glycine in relation to the medium containing only Krebs Ringer bicarbonate. Potassium 8.0 mM in incubation medium did not stimulate the protein synthesis compared to the medium containing 2.7 mM, and at 50 mM diminishes more than 2.5 times the protein synthesis compared to the other concentration. Only at the concentration of 5.0 mM, 2-deoxy-d-glucose inhibited the CO₂ production and lipid synthesis from l-[U-¹⁴C] leucine. This compound did not inhibit either CO₂ production, or lipid synthesis from [1-¹⁴C]glycine. Lactate at 10 mM and glucose 5.0 mM did not revert the inhibitory effect of 2-deoxy-d-glucose on the protein synthesis from l-[U-¹⁴C]leucine. 2-deoxy-d-glucose at 2.0 mM did not show any effect either on CO₂ production, or on lipid synthesis from l-[U-¹⁴C]lactate 10 mM and glucose 5.0 mM.     

Effect of short and long periods of separation on agonistic behaviour,injuries and stress in Hérens cows kept in loose housing

Hérens cows are typically not dehorned and are therefore housed in tie-barns during winter. Recently, however, farmers have started to also use loose housing systems. They separate single cows from their herd for periods of a few days to ensure undisturbed calving and to avoid excessive activity caused by animals in oestrus. As these cows are highly motivated to fight, the re-introduction of individuals after separation is usually associated with increased agonistic behaviour. The aim of this study was to compare the effects of the length of separation with regard to behaviour, injuries and stress response.The study was conducted with 45 focal horned Hérens cows kept in four groups of 10, 20, 18 and 21 cows respectively on two Swiss farms: two groups were kept as suckler cows and two groups as dairy cows. Each focal cow was separated on two occasions, once for a short (median: 1 day; high oestrus in dairy, late pregnancy or lactation in suckler cows) and once for a longer (median: 2 days; high oestrus in dairy, calving in suckler cows) period. During the 6 h following the re-introduction, agonistic behaviour was recorded. Occurrence of fresh wounds was noted 10 h after re-introduction. As an indicator of physiological stress, faecal samples were collected and concentrations of the cortisol metabolite 11,17-dioxoandrostanes (11,17-DOA) were determined. All data were analysed using generalised linear mixed-effects models.Frequency and duration of agonistic interaction increased with longer separation (p < 0.02) and quickly decreased during the hours following the re-introduction of the focal cow (p < 0.001). The risk of injuries did not significantly change with duration of separation. Separating the cow from her group brought about an increase in concentration of 11,17-DOA (p = 0.012) that decreased over time (p < 0.001). Interestingly, concentrations during the re-introduction phase were lower in comparison with the separation phase (p < 0.001). The concentration of 11,17-DOA was lower during the longer separations (p = 0.018). We did not find any difference of practical importance in how cows reacted to long compared to the short separation related to the different hormonal states of dairy and suckler cows during separation, nor related to the changes in hormonal state within the suckler cows.In conclusion, the duration of a separation of a single Hérens cow from her herd should be minimised so as to reduce negative effects resulting from agonistic interactions.     

Effect of leptin on insulin resistance of muscle--direct or indirect?

We examined the effect of leptin on the insulin resistance in skeletal muscles by measuring glucose transport. Male Wistar rats were fed rat chow or high-fat diets for 30 days. Before sacrifice, rats fed high-fat diet were subcutaneously injected with leptin (1 mg/kg b.w.) for 3 days. The glucose transport in epitrochlearis and soleus muscles did not differ in the experimental groups under basal conditions, however these values decreased significantly in the rats fed high-fat diet under insulin stimulation (p<0.01). Leptin treatment recovered the decreased glucose transport in epitrochlearis (p<0.05) and soleus muscles (p=0.08). Triglyceride concentrations in soleus muscles were increased significantly in the rats fed high-fat diet as compared to rats fed chow diet (p<0.01), and were decreased significantly by leptin treatment (p<0.01). The glucose transport was measured under basal conditions and after 60 microU/ml of insulin treatment with or without 50 ng/ml of leptin. Leptin had no direct stimulatory effect on glucose transport under both basal and insulin-stimulated conditions in vitro. These results demonstrate that leptin injection to rats fed high-fat diet recovered impaired insulin responsiveness of skeletal muscles and muscle triglyceride concentrations. However, there was no direct stimulatory effect of leptin on insulin sensitivity of skeletal muscles in vitro.     

Effect of prostaglandins E2 and F2α on in vitro development and hatching of caprine blastocysts

Prostaglandin E₂ has been shown to increase the ovine embryo hatching rate, and PGF_2α to reduce the development of rabbit, bovine, and rat embryos. The objective was to determine the effects of PGE₂ and PGF_2α on development of caprine embryos. Estrus was synchronized in does (n = 25) with medroxyprogesterone acetate (MAP) intravaginal sponges for 12 days, and superovulated with 20 units of FSH. On day 6 following estrus, embryos were flushed (n = 128) and incubated individually per well in 25 μl droplets of TCM-199 and BSA (8 mg/ml) for 6 days at 38.5 °C in a 5% CO₂: air with one of the following treatments: (1) control (0.0002% EtOH), (2) PGE₂ (7 ng/ml), (3) PGF_2α (7 ng/ml), (4) low PGE₂:high PGF_2α (3.5 ng/ml:14 ng/ml), (5) balanced PGE₂:PGF_2α (7 ng/ml:7 ng/ml), or (6) high PGE₂:low PGF_2α (14 ng/ml:3.5 ng/ml). Treatment with PGE₂ alone reduced (P < 0.05) the hatching rate (1/15; 7%). The hatching rate of embryos treated with PGF_2α alone (9/18; 50%), low PGE₂:high PGF_2α (8/16; 50%), and balanced PGE₂:PGF_2α (11/16; 69%) were similar to control (6/18; 33%). In contrast, the hatching rate was non-significantly increased (13/18; 72%) with the high PGE₂:low PGF_2α treatment. None of the treatments affected development from the morula to blastocyst stage. From the current data, it can be concluded that PGE₂ alone reduced hatching rate, and PGF_2α alone had no effect on the development of caprine embryos. High concentrations of PGE₂ with PGF_2α improved the hatching rates. Thus, uterine concentrations of PGE₂ may need to reach a threshold level to improve embryo hatching, as previously reported, while increased uterine concentrations of PGF_2α during early pregnancy would not affect development of the embryo.     

Effect of γ-irradiation on F-2 and T-2 toxin production in corn and rice

Fusarium graminearum andF. tricinctum were grown on moistened corn and rice. After inoculation the substrates were exposed to γ-irradiation and growth rate together with mycotoxin production were measured. A delay in mycelium growth and an increase in F-2 and T-2 toxin production occurred after irradiation with 1 and 3 kGy. The maximum F-2 production was 10.7 mg/kg on rice at 3 kGy, whereas T-2 was 735 μg/kg on rice at 3 kGy. At 9 kGy neither growth nor toxin production could be detected in any inoculated corn and rice substrate.     

Risk factors in the spread of leishmaniases: towards integrated monitoring?

Environmental changes, immune status and treatment failure constitute the three major risk factors for the (re-)emergence and spread of leishmaniases. Except for Leishmania-HIV co-infection, these risk factors are not systematically monitored and their interaction is poorly studied and understood. Recently, the multidisciplinary network Leish-Med was launched to document this issue around the Mediterranean and to promote transborder control strategies.     

Effect of Anoxia on α-Amylase Induction in Maize Caryopsis

α -amylase as well as other enzymes involved in starch degradation under anoxia. Carbohydrates resulting from starch breakdown allow maize caryopses to avoid sugar starvation. Most interestingly, this correlates well with the ability of maize caryopses to sustain relatively prolonged anaerobiosis, in agreement with the hypothesis linking carbohydrate availability to anoxia tolerance. Received 25 September 1999/ Accepted in revised form 24 February 2000     

The coming of age of niche vaccines?: Effect of vaccines on resistance profiles in Streptococcus pneumoniae

Pneumococcal conjugate vaccine is not only effective against invasive and non-invasive disease in all ages but also has a significant impact on antibiotic-resistant infections since a number of resistant serotypes are targeted by the vaccine. Surveillance studies in the post-licensure years have shown an increase in non-vaccine types both in carriage and disease isolates. There appears to be an increasing trend in antimicrobial resistance among these non-vaccine types, especially in serotype 19A. The impact these non-vaccine types will have on disease remains to be seen, but clearly continued efforts at characterizing the pneumococcal population are essential for future surveillance. Although expanded vaccine formulations with efficacy against a wider range of serotypes will be useful, reduction of drug-resistant Streptococcus pneumoniae will require a combination of the conjugate vaccine and a reduction in antimicrobial use.