Genetic Diversity of Isolates of Glomus mosseae from Different Geographic Areas Detected by Vegetative Compatibility Testing and Biochemical and Molecular Analysis

We detected, for the first time, the occurrence of vegetative incompatibility between different isolates of the arbuscular mycorrhizal fungal species Glomus mosseae. Vegetative compatibility tests performed on germlings belonging to the same isolate showed that six geographically different isolates were capable of self-anastomosing, and that the percentage of hyphal contacts leading to fusions ranged from 60 to 85%. Successful anastomoses were characterized by complete fusion of hyphal walls, protoplasm continuity and occurrence of nuclei in the middle of hyphal bridges. No anastomoses could be detected between hyphae belonging to different isolates, which intersected without any reaction in 49 to 68% of contacts. Microscopic examinations detected hyphal incompatibility responses in diverse pairings, consisting of protoplasm retraction from the tips and septum formation in the approaching hyphae, even before physical contact with neighboring hyphae. Interestingly, many hyphal tips showed precontact tropism, suggesting that specific recognition signals may be involved during this stage. The intraspecific genetic diversity of G. mosseae revealed by vegetative compatibility tests was confirmed by total protein profiles and internal transcribed spacer-restriction fragment length polymorphism profiles, which evidenced a higher level of molecular diversity between the two European isolates IMA1 and BEG25 than between IMA1 and the two American isolates. Since arbuscular mycorrhizal fungi lack a tractable genetic system, vegetative compatibility tests may represent an easy assay for the detection of genetically different mycelia and an additional powerful tool for investigating the population structure and genetics of these obligate symbionts.     

Swimming training induces liver adaptations to oxidative stress and insulin sensitivity in rats submitted to high-fat diet

Oxidative stress, physical inactivity and high-fat (FAT) diets are associated with hepatic disorders such as metabolic syndrome (MS). The therapeutic effects of physical training (PT) were evaluated in rats with MS induced by FAT diet for 13 weeks, on oxidative stress and insulin signaling in the liver, during the last 6 weeks. FAT-sedentary (SED) rats increased body mass, retroperitoneal fat, mean arterial pressure (MAP) and heart rate (HR), and total cholesterol, serum alanine aminotransferase, glucose and insulin. Livers of FAT-SED rats increased superoxide dismutase activity, thiobarbituric acid-reactive substances, protein carbonyl and oxidized glutathione (GSSG); and decreased catalase activity, reduced glutathione/GSSG ratio, and the mRNA expression of insulin receptor substrate 1 (IRS-1) and serine/threonine kinase 2. FAT-PT rats improved in fitness and reduced their body mass, retroperitoneal fat, and glucose, insulin, total cholesterol, MAP and HR; and their livers increased superoxide dismutase and catalase activities, the reduced glutathione/GSSG ratio and the expression of peroxisome proliferator-activated receptor gamma and insulin receptor compared to FAT-SED rats. These findings indicated adaptive responses to PT by restoring the oxidative balance and insulin signaling in the liver and certain biometric and biochemical parameters as well as MAP in MS rats.     

Bioerosion caused by foraging of the tropical chiton Acanthopleura gemmata at One Tree Reef, southern Great Barrier Reef

The bioerosive potential of the intertidal chiton Acanthopleura gemmata on One Tree Reef was determined by quantification of CaCO₃ in daily faecal pellet production of individuals transplanted into mesocosms after nocturnal-feeding forays. Mean bioerosive potential was estimated at 0.16 kg CaCO₃ chiton⁻¹ yr⁻¹. Bioerosion rates were estimated for populations on two distinct chiton habitats, reef margin (0.013 kg CaCO₃ m⁻² yr⁻¹) and beachrock platform (0.25 kg CaCO₃ m⁻² yr⁻¹). Chiton density on the platform was orders of magnitude greater than on the reef margin. The surface-lowering rate (0.16 mm m⁻² yr) due to bioerosion by the beachrock population is a substantial contribution to the total surface-lowering rate of 2 mm m⁻² yr⁻¹ previously reported for One Tree Reef across all erosive agents. At high densities, the contribution of A. gemmata to coral reef bioerosion budgets may be comparable to other important bioeroders such as echinoids and fish.     

Triple helix conformation of botryosphaeran, a (1→3;1→6)-β-d-glucan produced by Botryosphaeria rhodina MAMB-05

Botryosphaeran, a (1→3;1→6)-β-d-glucan produced by Botryosphaeria rhodina MAMB-05, was found to be present in a triple helix conformation from helix–coil transition studies using Congo Red. The triple helix conformation was disrupted at increasing alkali concentrations. Conformational changes were also observed using phenanthrene as a fluorescent probe, and the fluorescence intensity decreased 80% in the presence of dimethyl sulfoxide. The results confirmed the triple helix conformation of botryosphaeran, an important property manifesting biological response modifying activity.     

Garden bird feeding predicts the structure of urban avian assemblages

Households across the developed world cumulatively spend many millions of dollars annually on feeding garden birds. While beneficial effects on avian assemblages are frequently claimed, the relationships between levels of garden bird feeding and local avian populations are unknown. Using data from a large UK city, we show that both avian species richness and abundance vary across different socioeconomic neighbourhood types. We examined whether patterns in bird feeding could explain this variation. The density of bird feeding stations across the urban environment was strongly positively related to avian abundance, after controlling for differences in habitat availability. This effect was almost exclusively driven by the abundance of those species known to utilize garden feeding stations frequently. In contrast, the density of feeding stations had no effect on avian species richness. We also examined variation in the proportion of households in different communities that provide food for birds, a factor that is not correlated with feeder density. The prevalence of bird feeding across different neighbourhoods declined as socioeconomic deprivation increased, and increased with avian species richness and abundance. Our results suggest that the provision of supplementary food for birds by multiple landowners across a city can impact the status of urban bird populations. The potential for harnessing these actions for conservation needs to be explored.     

Short-term effects of winter warming and acidification on phytoplankton growth and mortality: more losers than winners in a temperate coastal lagoon

Hydrobiologia - Changes in temperature and CO2 are typically associated with climate change, but they also act on shorter time scales, leading to alterations in phytoplankton physiology and...     

IL28B Gene Polymorphisms and US Liver Fatty Changes in Patients Who Spontaneously Cleared Hepatitis C Virus Infection

Background

Recent clinical studies have shown that the presence of CC genotype in the rs12979860 region of IL28B gene is associated with an increase in the probability of spontaneous clearance of hepatitis C virus (HCV). Moreover, IL28B polymorphism seems to influence the probability of developing liver steatosis in chronic HCV patients.

Aims

The aims of our clinical study were 1) to verify the distribution of IL28B genotypes (CC, CT or TT) among subjects with spontaneous clearance of HCV infection and 2) to examine the correlation between IL28B polymorphism and hepatic steatosis among these subjects.

Methods and patients

We enrolled 41 subjects with spontaneous resolution of HCV infection (detectable serum anti-HCV but undetectable HCV-RNA) and 134 healthy controls from the same geographical area. The IL28B single-nucleotide polymorphism (SNP) rs12979860 was genotyped by using a Pyrosequencing™ technique. The presence of steatosis was assessed by liver biopsy or ultrasound examination in the 41 study subjects.

Results

CC, CT and TT-genotypes of the SNP rs1979860 were found in 66%, 24% and 10% of the subjects who spontaneously cleared HCV and in 31%, 54% and 15% of controls, respectively (p = 0.0003). Among the study subjects, females with CC-genotype were significantly more represented (p = 0.02). Hepatic steatosis did not correlate with IL28B genotype (p = 0,14) but only with a high body mass index (BMI) value (p = 0.03).

Conclusions

Female subjects carrying IL28B CC-genotype are significantly more represented among Italian patients who spontaneously cleared HCV infection. In addition, among these subjects, the presence of liver steatosis does not correlate with IL28B genotype but is solely related to the occurrence of high BMI. Thus, the association between IL28B polymorphism and steatosis in chronic HCV patients requires the presence of active HCV replication to occur, while in subjects who have cleared the infection, the mechanism(s) inducing liver steatosis are independent from IL28B profile.     

Sustained Reduction of the Dengue Vector Population Resulting from an Integrated Control Strategy Applied in Two Brazilian Cities

Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg sampling coupled with geographic information systems technology. The SMCP-Aedes, a system based on open technology and open data standards, was set up from March/2008 to October/2011 as a pilot trial in two sites of Pernambuco -Brazil: Ipojuca (10,000 residents) and Santa Cruz (83,000), in a joint effort of health authorities and staff, and a network of scientists providing scientific support. A widespread infestation by Aedes was found in both sites in 2008–2009, with 96.8%–100% trap positivity. Egg densities were markedly higher in SCC than in Ipojuca. A 90% decrease in egg density was recorded in SCC after two years of sustained control pressure imposed by suppression of >7,500,000 eggs and >3,200 adults, plus larval control by adding fishes to cisterns. In Ipojuca, 1.1 million mosquito eggs were suppressed and a 77% reduction in egg density was achieved. This study aimed at assessing the applicability of a system using GIS and spatial statistic analysis tools for quantitative assessment of mosquito populations. It also provided useful information on the requirements for reducing well-established mosquito populations. Results from two cities led us to conclude that the success in markedly reducing an Aedes population required the appropriate choice of control measures for sustained mass elimination guided by a user-friendly mosquito surveillance system. The system was able to support interventional decisions and to assess the program’s success. Additionally, it created a stimulating environment for health staff and residents, which had a positive impact on their commitment to the dengue control program.     

Evidence from algal bioassays of seasonal nutrient limitations in two English lakes

Comparative laboratory bioassays using Asterionella formosa and Rhodomonas lacustris as test organisms were performed from March to November 1987 on filtered water samples from two English lakes, to assess their potential fertility and to identify possible limiting nutrients. The relative growth responses (log₂ increments) per week, were measured after additions of P, Fe, Si, N, and K singly and in combinations in comparison with unenriched (control) samples. Phosphate appeared to be the major limiting element for both species throughout the year, except during the spring diatom maxima when silicon usually becomes limiting. On most occasions chelated iron increased the growth increments, particularly in combination with phosphate. In general, the bioassay results showed correspondence with the nutrient concentrations in the test waters, which showed low (< 1 µg l^–1) levels of soluble reactive phosphate during all or most of the year and depleted silicon levels in late spring. Comparison between relative (incremental) ratio and absolute (cell concentration) response was made.