Effect of arsenic trioxide on metallothionein and its conversion to different arsenic metabolites in hen liver

The metabolism of arsenic, its affinity to metallothionein (MT), its influence on selenium levels, and its biotransformation to different metabolites in the liver tissue of laying hens exposed to arsenic trioxide (As2O3) was investigated. The experiment was performed with two groups of hens fed for 19 d with either a standard diet or with the same diet enriched in arsenic (30 microg/g). The major findings were as follows: 1. After 19 d exposure, about 65% of the total liver As was found in the water-soluble phase (100,000g centrifuged supernatant). In liver supernatant, As binding was found mostly in the range of very low-molecular-weight proteins (Mr < 10,000). Although after exposure the amount of MT-like proteins increased, the As bound to it was only in trace amounts. The protein was identified by convential procedures as Zn,Cu-thionein with traces of selenium and arsenic. 2. Arsenic exposure resulted in almost unchanged Se levels regarding its tissue concentrations and distribution between supernatant and pellet, where about 10% of total Se was found in the supernatant. On the contrary, As exposure did affect Cd levels. Tissue Cd concentration was slightly diminished, but the percentage of tissue Cd found in the water-soluble phase was increased from 20% to 40%. 3. In methanol extracts of tissue and supernatant of the As-exposed group, only two arsenic compounds were detected, As(III) and dimethylarsinic acid (DMA), the latter prevailing.     

Cathepsin B inhibitors: Further exploration of the nitroxoline core

Human cathepsin B is a cysteine protease with many house-keeping functions, such as intracellular proteolysis within lysosomes. Its increased activity and expression have been strongly associated with many pathological processes, including cancers. We present here the design and synthesis of novel derivatives of nitroxoline as inhibitors of cathepsin B. These were prepared either by omitting the pyridine part, or by modifying positions 2, 7, and 8 of nitroxoline. All compounds were evaluated for their ability to inhibit endopeptidase and exopeptidase activities of cathepsin B. For the most promising inhibitors, the ability to reduce extracellular and intracellular collagen IV degradation was determined, followed by their evaluation in cell-based in vitro models of tumor invasion. The presented data show that we have further defined the structural requirements for cathepsin B inhibition by nitroxoline derivatives and provided additional knowledge that could lead to non-peptidic compounds with usefulness against tumor progression.     

Effect of fruit host on wing morphology in Drosophila suzukii (Diptera: Drosophilidae): A first view using geometric morphometrics

The invasive alien fruit pest Drosophila suzukii, (Matsumura 1931) causes economic loss in soft‐skinned fruit production across Europe. After its first detection in 2008, the species has successfully expanded to a wide geographic area and invaded new host plants in a relatively short period of time. The aim of the present study was to analyze the connection between food preferences as host specialization and the morphology of D. suzukii. Population morphological variation in wings was investigated in two different host fruits (grape and strawberry) in which economic damage has been recorded. The geometric morphometric results revealed two noticeable wing shape morphotypes in D. suzukii (i.e. vein configuration) between the grape and strawberry fruits. Flies reared in grapes had wider wings, whereas flies grown in strawberries had more narrow wings. These differences in morphotype could be explained by the effects of wing aerodynamics, which affect the strength of the wings in flight. This, in turn, can lead to better dispersion within the associated fruit host. These results confirm that this extremely invasive species, found worldwide, is successful at spreading in part because of its potential to adapt rapidly under different rearing conditions. Therefore, adaptive variations in the wing shape of D. suzukii can be used to differentiate populations based on food preference (e.g. soft fruits) and can serve as an additional tool for detecting different bioecological types of D. suzukii.     

A metabolic syndrome in terrestrial ectotherms with different elevational and distribution patterns

The metabolic performance of ectotherms is expected to be driven by the environment in which they live. Ecologically similar species with contrasting elevation distributions occurring in sympatry at mid‐elevations, provide good models for studying how physiological responses to temperature vary as a function of adaptation to different elevations. Under sympatry, at middle elevations, where divergent species ranges overlap, sympatric populations are expected to have similar thermal responses, suggesting similar local acclimation or adaptation, while observed differences would suggest adaptation to each species’ core range. We analysed the metabolic traits of sympatric species pairs from three ectotherm groups: reptiles (Reptilia: Lacertidae), amphibians (Amphibia: Salamandridae) and beetles (Coleoptera: Carabidae), living at different elevations, in order to test how adaptation to different elevations affects metabolic responses to temperature. We experimentally tested the thermal response of respiration rate (RR) and estimated potential metabolic activity (PMA) at three temperature regimes surrounding the groups’ optimal activity body temperatures. RR was relatively similar among groups and showed a positive response to increasing temperature, which was more pronounced in the high‐elevation species of reptiles and beetles. Relative to RR, PMA displayed a stronger and more consistent positive response to increased temperature in all three groups. For all three groups, the average biochemical capacity for metabolism (PMA) was higher in the range‐restricted, high‐elevation species, and this difference increased at higher temperatures in a consistent manner. These results, indicating consistent pattern in three independently evolved animal groups, suggest a ubiquitous adaptive syndrome and represent a novel understanding of the mechanisms shaping spatial biodiversity patterns. Our results also highlight the importance of geographic patterns for the mechanistic understanding of adaptations in physiological traits, including species’ potential to respond/adapt to global climate changes.     

Two-patch population models with adaptive dispersal: the effects of varying dispersal speeds

The population-dispersal dynamics for predator–prey interactions and two competing species in a two patch environment are studied. It is assumed that both species (i.e., either predators and their prey, or the two competing species) are mobile and their dispersal between patches is directed to the higher fitness patch. It is proved that such dispersal, irrespectively of its speed, cannot destabilize a locally stable predator–prey population equilibrium that corresponds to no movement at all. In the case of two competing species, dispersal can destabilize population equilibrium. Conditions are given when this cannot happen, including the case of identical patches.     

USE OF ULTRASONIC SPECTROSCOPY AND VISCOSIMETRY FOR THE CHARACTERIZATION OF CHICKEN SKIN COLLAGEN IN COMPARISON WITH COLLAGENS FROM OTHER ANIMAL TISSUES

Use of traditional sources of collagen such as pork, bovine, and carp has some limitations. Chicken skin can be valuable alternative. In this work collagen was isolated from chicken skin using a modified procedure. Molecular properties of chicken collagen were analyzed and compared to collagen from other animal skins. Acid-soluble collagen type I was obtained with a yield of 25% and water content around 67%. Viscosimetry and ultrasonic spectroscopy were newly used for molecular characterization. By ultrasonic attenuation measurements, a pre-aggregation phase in the interval from 20°C to 27°C was observed, which is a proof of disaggregation and liquefaction. From 40°C upward, the liquefaction process finishes and aggregation continues. In a bovine sample this phenomenon starts at 40°C, in chicken at 50°C, and continues until 70°C. By viscosimetry, the denaturation temperature was confirmed as 40°C for bovine and 50°C for chicken collagen. Chicken collagen has a two times higher lysine level than bovine, which provides molecular stability side-chain interactions. With regard to higher thermal stability and favorable amino acid composition, waste chicken skin has the potential to be an excellent alternative source of raw collagen with applications in the food industry and biomedicine.     

The effects of 12-week progressive strength training on strength,functional capacity,metabolic biomarkers,and serum hormone concentrations in healthy older women: morning versus evening training

ABSTRACT

Previous findings suggest that performing strength training (ST) in the evening may provide greater benefit for young individuals. However, this may not be optimal for the older population. The purpose of this study was to compare the effects of a 12-week ST program performed in the morning vs. evening on strength, functional capacity, metabolic biomarker and basal hormone concentrations in older women. Thirty-one healthy older women (66 ± 4 years, 162 ± 4 cm, 75 ± 13 kg) completed the study. Participants trained in the morning (M) (07:30, n = 10), in the evening (E) (18:00, n = 10), or acted as a non-training control group (C) (n = 11). Both intervention groups performed whole-body strength training with 3 sets of 10–12 repetitions with 2–3 minutes rest between sets. All groups were measured before and after the 12-week period with; dynamic leg press and seated-row 6-repetition maximum (6-RM) and functional capacity tests (30-second chair stands and arm curl test, Timed Up and Go), as well as whole-body skeletal muscle mass (SMM) (kg) and fat mass (FM-kg, FM%) assessed by bioelectrical impedance (BIA). Basal blood samples (in the intervention groups only) taken before and after the intervention assessed low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), blood glucose (GLU), triglycerides (TG), high-sensitive C-reactive protein (hsCRP) concentrations and total antioxidant status (TAS) after a 12 h fast. Hormone analysis included prolactin (PRL), progesterone (P) estradiol (ESTR), testosterone (T), follicle stimulating hormone (FSH), and luteinizing hormone (LH). While C showed no changes in any variable, both M and E significantly improved leg press (+ 46 ± 22% and + 21 ± 12%, respectively; p < 0.001) and seated-row (+ 48 ± 21% and + 42 ± 18%, respectively; p < 0.001) 6-RM, as well as all functional capacity outcomes (p < 0.01) due to training. M were the only group to increase muscle mass (+ 3 ± 2%, p < 0.01). Both M and E group significantly (p < 0.05) decreased GLU (–4 ± 6% and –8 ± 10%, respectively), whereas significantly greater decrease was observed in the E compared to the M group (p < 0.05). Only E group significantly decreased TG (–17 ± 25%, p < 0.01), whereas M group increased (+ 15%, p < 0.01). The difference in TG between the groups favored E compared to M group (p < 0.01). These results suggest that short-term “hypertrophic” ST alone mainly improves strength and functional capacity performance, but it influences metabolic and hormonal profile of healthy older women to a lesser extent. In this group of previously untrained older women, time-of-day did not have a major effect on outcome variables, but some evidence suggests that training in the morning may be more beneficial for muscle hypertrophy (i.e. only M significantly increased muscle mass and had larger effect size (M: g = 2 vs. E: g = 0.5).     

Genetic evidence for the identity of Caulerpa racemosa (Forsskål) J. Agardh (Caulerpales,Chlorophyta) in the Adriatic Sea

Three taxa of Caulerpa racemosa that differ morphologically and genetically have been reported in the Mediterranean Sea. The ‘invasive variety’ was recorded for the first time in the early 1990s in Libya. In less than 10 years, it was found in almost all parts of the Mediterranean. The first record of C. racemosa in the Croatian part of the Adriatic Sea was in 2000 and as many as 35 different localities were established by the end of 2004. In terms of morphology, the specimens from the Adriatic Sea resemble the ‘invasive variety’. To confirm this, we analysed populations from two different localities (the island of Mljet and the peninsula of Pelje?ac) using the ITS1-5.8S-ITS2 region of 18S-5.8S-26S rDNA unit as a molecular marker. The ITS1-5.8S-ITS2 region from nine individual plants was amplified by PCR, cloned in a pCR 2.1 vector and sequenced. Phylogenetic comparison of sequences from specimens found in the Adriatic Sea with specimens of the same and similar taxa, found both inside and outside the Mediterranean, provided genetic evidence that C. racemosa populating the Adriatic Sea corresponds to the Mediterranean C. racemosa var. cylindracea (Sonder) Verlaque, Huisman?&?Boudouresque, i.e. to the ‘invasive variety’.     

Biochemical and crystallographic characterization of a glucansucrase from Lactobacillus reuteri 180

Glucansucrases are large extracellular transglycosidases secreted by lactic acid bacteria. Using sucrose as a substrate they synthesize high molecular mass α-glucans or, in the presence of suitable acceptor molecules, low molecular mass oligosaccharides. Although about 60 glucansucrases have been classified in glycoside hydrolase family GH70, no three-dimensional structure has been reported for any. With the aim of solving the first structure of a GH70 glucansucrase, purification and crystallization experiments were performed with a fully active, 117 kDa N-terminally truncated fragment of glucansucrase GTF180 from Lactobacillus reuteri 180 (residues 742–1772). Crystallization experiments yielded crystals that belong to two different triclinic crystal forms (space group P1) and one orthorhombic crystal form (space group P2₁2₁2₁). Native data sets for both triclinic and the orthorhombic crystals were collected at 1.7 and 2.0 Å resolution, respectively. Enzyme activity assays, pH and temperature optima show comparable values for both the full-length and the N-terminally truncated GTF180.     

Research Note: Postnatal Development of Electrolyte Transport in Calf Rumen as Affected by Weaning Time

In a previous study we found a positive correlation between early weaning in calves and morphological parameters which were indicative of ruminal development, i.e. the length and width of the papillae. The objective of the present study was to determine to what extent this observation could be reflected by modulations of absorptive and secretory functions of the rumen mucosa. For this purpose the short-circuit currents (I sc ) as a measure of electrogenic net ion fluxes and the transepithelial conductances (G T ) as a measure of the overall tissue permeability were measured in vitro applying the Ussing-chamber technique. Simultaneously, the unidirectional flux rates of sodium and chloride across rumen wall epithelia were determined in the absence of electrochemical gradients. Under these conditions, significant positive net flux rates (J net ) clearly indicate active mechanisms for electrolyte absorption. For the experiments 12 male Holstein calves 7d of age were assigned to three groups of 4 animals each: milk group (I, slaughtered after 6 weeks of age), late weaning group (II, slaughtered after 9 weeks of age) and early weaning group (II, weaned after 6 weeks of age and slaughtered after 9 weeks of age). Whereas G T values remained unaffected by different age and feeding, I sc values were significantly affected by early weaning but were not influenced by age. Irrespective of weaning time active absorption of Na + tended to be higher by about 60% in 9 weeks old animals. Active absorption of chloride was significantly increased in milk fed 9 weeke old calves and this effect was further stimulated by early weaning. In conclusion, the data show an increasing active Na + absorption with age in calf rumen that could not be influenced by early weaning. Similarly, active Cl m absorption was initially increased during postnatal development and this effect could be stimulated further by early weaning.