Community level impacts of invasive mosquitofish may exacerbate the impact to a threatened amphibian

Invasive fish threaten many native freshwater fauna. However, it can be difficult to determine how invasive fish impact animals with complex life cycles as interaction may be driven by either predation of aquatic larvae or avoidance of fish‐occupied waterbodies by the terrestrial adult stage. Mosquitofish (Gambusia spp.) are highly successful and aggressive invaders that negatively impact numerous aquatic fauna. One species potentially threatened by Gambusia holbrooki is the green and golden bell frog (Litoria aurea). However, G. holbrooki's role in this frog's decline was unclear due to declines driven by the chytrid fungal disease and the continued co‐existence of these fish and frogs in multiple locations. To clarify the extent to which Gambusia is impacting L. aurea, we conducted 3 years of field surveys across a deltaic wetland system in south‐east Australia. We measured the presence and abundance of aquatic taxa including G. holbrooki, and L. aurea frogs and tadpoles, along with habitat parameters at the landscape and microhabitat scale. Generalized linear models were used to explore patterns in the abundance and distributions of L. aurea and G. holbrooki. We found strong negative associations between G. holbrooki and tadpoles of most species, including L. aurea, but no apparent avoidance of G. holbrooki by adult frogs. Native invertebrate predators (Odonata and Coleoptera) were also absent from G. holbrooki‐occupied ponds. Due to the apparent naivety of adult frogs toward G. holbrooki, the separation of G. holbrooki and tadpoles, plus the abundance of alternative predators in G. holbrooki‐free ponds, we conclude that the impact of G. holbrooki on L. aurea recruitment is likely substantial and warrants management action.     

Probing the metal ion selectivity in methionine aminopeptidase via changes in the luminescence properties of the enzyme bound europium ion

We report herein, for the first time, that Europium ion (Eu³⁺) binds to the “apo” form of Escherichia coli methionine aminopeptidase (EcMetAP), and such binding results in the activation of the enzyme as well as enhancement in the luminescence intensity of the metal ion. Due to competitive displacement of the enzyme-bound Eu³⁺ by different metal ions, we could determine the binding affinities of both “activating” and “non-activating” metal ions for the enzyme via fluorescence spectroscopy. The experimental data revealed that among all metal ions, Fe²⁺ exhibited the highest binding affinity for the enzyme, supporting the notion that it serves as the physiological metal ion for the enzyme. However, the enzyme-metal binding data did not adhere to the Irving-William series. On accounting for the binding affinity vis a vis the catalytic efficiency of the enzyme for different metal ions, it appears evident that that the “coordination states” and the relative softness” of metal ions are the major determinants in facilitating the EcMetAP catalyzed reaction.     

New water mites of the family Hygrobatidae (Acari,?Hydrachnidia) from Turkey

In this study, the findings of three water mite species of the family Hygrobatidae collected from different streams in Turkey were evaluated. Hygrobates (s. str.) anatolicus Esen & Pešić, sp. n. is described as new for science. Hygrobates (Rivobates) diversiporus Sokolow, 1927 and Atractides (s. str.) nikooae Pešić, 2004, which were illustrated and thoroughly discussed, are new records for the Turkish fauna.     

Effect of losartan on the blood-brain barrier permeability in diabetic hypertensive rats

Our previous publication has stressed the benefits of losartan, an angiotensin II receptor blocker, on the permeability of blood-brain barrier (BBB) and blood pressure during L-NAME-induced hypertension. This study reports the impacts of anti-hypertensive treatment by losartan on the brain endothelial barrier function and the arterial blood pressure, during acute hypertension episode, in experimentally diabetic hypertensive rats. Systolic blood pressure measurements were taken with tail cuff method before and during administration of L-NAME (0.5 mg/ml). We induced diabetes by using alloxan (50 mg/kg, i.p). Losartan (3 mg/kg, i.v) was given to rats following the L-NAME treatment. Acute hypertensive vascular injury was induced by epinephrine (40 microg/kg). The BBB disruption was quantified according to the extravasation of the Evans blue (EB) dye. L-NAME induced a significant increase in arterial blood pressure on day 14 in normoglycemic and hyperglycemic rats (p < 0.05). Losartan significantly reduced the increased blood pressure in hypertensive and diabetic hypertensive rats (p < 0.01). Epinephrine-induced acute hypertension in diabetic hypertensive rats increased the content of EB dye dramatically in cerebellum and diencephalon (p < 0.01) and slightly in both cerebral cortex (p < 0.05). Losartan treatment reduced the increased BBB permeability to EB dye in the brain regions of diabetic hypertensive rats treated with epinephrine (p < 0.05). This study indicates that, in diabetic hypertensive rats, epinephrine administration leads to an increase in microvascular-EB-albumin efflux to brain, however losartan treatment significantly attenuates this protein's transport to brain tissue.     

Conventional and microwave-assisted synthesis of ZnO nanorods and effects of PEG400 as a surfactant on the morphology

Conventional and microwave-assisted synthesis of ZnO nanorods have been performed with and without using PEG400. ZnO nanorods were synthesized with 50-250 nm of diameter which depends on the used surfactant and methods. Surfactant effects of PEG400 on the size and morphology of ZnO nanorods were investigated. The microwave method was compared to the conventional heating method. Morphologies were investigated by using scanning electron microscopy (SEM).     

Seroprevalence of Borrelia burgdorferi infection among forestry workers and farmers in Duzce, north-western Turkey

Borrelia burgdorferi infection is the most frequent tick-transmitted disease worldwide. Our aim was to assess the seroprevalence of B. burgdorferi infection among forestry workers and farmers in Duzce, in the north-west region of Turkey. Blood samples from 349 forestry workers and farmers and 193 healthy blood donors were obtained to determine the presence of antibodies to B. burgdorferi. A two-step testing strategy was used; the sera were initially tested by ELISA and then by Western blot (WB) IgG. Demographic data regarding residence, age, gender, profession, tick bite history, contact with animals, and symptoms involving the skin, nervous system, and osteoarticular system were collected by questionnaire. All results were evaluated statistically using the chi2 test. The seroprevalence of B. burgdorferi was 10.9% (n=38) in forestry workers and farmers and 2.6% (n=5) in blood donors by ELISA, with a statistically significant difference (p<0.001). Seropositivity rates were related to age, gender, and common risk factors for the disease. IgG seropositivity was confirmed in four (1.1%) sera by WB. In this first seroepidemiological report from the northwest region of Turkey, tick bite exposure was found to be high, whereas B. burgdorferi infection was not common. Preventive measures against tick exposure and further studies to determine the distribution of Lyme disease in Turkey are proposed.     

Characterization of a novel linkage unit between ribitol teichoic acid and peptidoglycan in Listeria monocytogenes cell walls

The structure of the linkage unit between ribitol teichoic acid and peptidoglycan in the cell walls of Listeria monocytogenes EGD was studied. A teichoic-acid--glycopeptide preparation isolated from lysozyme digests of the cell walls of this strain contained mannosamine, glycerol, glucose and muramic acid 6-phosphate in an approximate molar ratio of 1:1:2:1, together with large amounts of glucosamine and other components of teichoic acid and glycopeptides. A teichoic-acid-linked sugar preparation, obtained by heating the cell walls at pH 2.5, also contained glucosamine, mannosamine, glycerol and glucose in an approximate molar ratio of 25:1:1:2. Part of the glucosamine residues were shown to be involved in the linkage unit. Thus, on mild alkaline hydrolysis, the teichoic-acid-linked sugar preparation gave a disaccharide characterized as N-acetylmannosaminyl(beta 1----4)-N-acetylglucosamine [ManNAc(beta 1----4)GlcNAc] in addition to the ribitol teichoic acid moiety, whereas the teichoic-acid - glycopeptide was separated into disaccharide-linked glycopeptide and the ribitol teichoic acid moiety by the same procedure. Furthermore, Smith degradation of the cell walls gave a characteristic fragment, EtO2-P-Glc(beta 1----3)Glc(beta 1----1/3)Gro-P-ManNAc(beta 1----4)GlcNAc (where EtO2 = 1,2-ethylenediol and Gro = glycerol). The results lead to the conclusion that in the cell walls of this organism, the ribitol teichoic acid chain is linked to peptidoglycan through a novel linkage unit, Glc(beta 1----3)Glc(beta 1----1/3)Gro-P-(3/4)ManNAc-(beta 1----4)GlcNAc.     

The comparison between cool and warm-hot environments on lipolytic response during prolonged exercise

The purpose of this study was to investigate the effect of cool exposure on lipolytic response during prolonged intermediate-intensity exercise in humans. Eight male subjects participated in this study; they performed 120-min cycle ergometer exercise at 60% of maximal oxygen uptake (VO2max) in a climatic chamber at 10 degrees C (C) and 30 degrees C (WH). There were no significant differences in oxygen uptake and respiratory exchange ratio between the two conditions during the prolonged exercise. Significant influences of cool exposure were observed in the changes in both heart rate and rectal temperature (p<0.01). Although cool exposure had no significant effects on plasma triglyceride, free fatty acid, and glycerol levels, changes in adrenaline and noradrenaline levels at C were significantly lower than WH during the prolonged exercise (p<0.01). Changes in the ratio of glycerol to noradrenaline (Gly/Nad), as an index of lipolytic efficiency, were significantly high at C as compared with WH (p<0.01). These results suggest that cool exposure has an influence on lipid metabolism during prolonged intermediate-intensity exercise, from the viewpoint of efficiency in lipolysis.