Habitat selection and temporal abundance fluctuations of demersal cartilaginous species in the Aegean Sea (eastern Mediterranean)

Predicting the occurrence of keystone top predators in a multispecies marine environment, such as the Mediterranean Sea, can be of considerable value to the long-term sustainable development of the fishing industry and to the protection of biodiversity. We analysed fisheries independent scientific bottom trawl survey data of two of the most abundant cartilaginous fish species (Scyliorhinus canicula, Raja clavata) in the Aegean Sea covering an 11-year sampling period. The current findings revealed a declining trend in R. clavata and S. canicula abundance from the late '90 s until 2004. Habitats with the higher probability of finding cartilaginous fish present were those located in intermediate waters (depth: 200-400 m). The present results also indicated a preferential species' clustering in specific geographic and bathymetric regions of the Aegean Sea. Depth appeared to be one of the key determining factors for the selection of habitats for all species examined. With cartilaginous fish species being among the more biologically sensitive fish species taken in European marine fisheries, our findings, which are based on a standardized scientific survey, can contribute to the rational exploitation and management of their stocks by providing important information on temporal abundance trends and habitat preferences.     

Vesicular glutamate transporter modulates sex differences in dopamine neuron vulnerability to age‐related neurodegeneration

Age is the greatest risk factor for Parkinson''s disease (PD) which causes progressive loss of dopamine (DA) neurons, with males at greater risk than females. Intriguingly, some DA neurons are more resilient to degeneration than others. Increasing evidence suggests that vesicular glutamate transporter (VGLUT) expression in DA neurons plays a role in this selective vulnerability. We investigated the role of DA neuron VGLUT in sex‐ and age‐related differences in DA neuron vulnerability using the genetically tractable Drosophila model. We found sex differences in age‐related DA neurodegeneration and its associated locomotor behavior, where males exhibit significantly greater decreases in both DA neuron number and locomotion during aging compared with females. We discovered that dynamic changes in DA neuron VGLUT expression mediate these age‐ and sex‐related differences, as a potential compensatory mechanism for diminished DA neurotransmission during aging. Importantly, female Drosophila possess higher levels of VGLUT expression in DA neurons compared with males, and this finding is conserved across flies, rodents, and humans. Moreover, we showed that diminishing VGLUT expression in DA neurons eliminates females'' greater resilience to DA neuron loss across aging. This offers a new mechanism for sex differences in selective DA neuron vulnerability to age‐related DA neurodegeneration. Finally, in mice, we showed that the ability of DA neurons to achieve optimal control over VGLUT expression is essential for DA neuron survival. These findings lay the groundwork for the manipulation of DA neuron VGLUT expression as a novel therapeutic strategy to boost DA neuron resilience to age‐ and PD‐related neurodegeneration.     

Effect of sibutramine on regional fat pads and leptin levels in rats fed with three isocaloric diets

AIM: The aim of the study was to investigate: a) the differential effect of the three main macronutrients on food intake, fat depots and serum leptin levels and b) the impact of sibutramine on the above parameters in rats fed ad libitum with three isocaloric diets. METHODS: Three groups of male Wistar rats (n = 63) were fed with a high fat diet (HFD), a high carbohydrate diet (HCD) or a high protein diet (HPD) for 13 weeks. In the last three weeks, each group was divided into three subgroups and received sibutramine (S) either at 5 mg/kg or 10 mg/kg, or vehicle. Food intake was measured daily during the last week of the experiment; perirenal and epididymal fat and fat/lean ratio were calculated and serum leptin was assayed. RESULTS: HFD-fed rats demonstrated elevated food intake and higher regional fat depots. S at 10 mg/kg decreased food intake in the HFD and epididymal fat in the HCD group. S also reduced perirenal fat in the HCD and HPD groups. Leptin levels were higher in rats fed with either the HFD or the HPD compared to those fed with the HCD. Moreover, S at 10 mg/kg decreased serum leptin levels in the HPD group. CONCLUSIONS: Results suggest a preferential effect of S on perirenal visceral fat and support the view that body fat loss is greater when its administration is accompanied by a HCD diet. No effect of S on leptin levels was found, besides that expected as a result of the decrease in body fat.     

The Microtubule Plus-End Tracking Proteins SPR1 and EB1b Interact to Maintain Polar Cell Elongation and Directional Organ Growth in Arabidopsis

The microtubule plus-end tracking proteins (+TIPs) END BINDING1b (EB1b) and SPIRAL1 (SPR1) are required for normal cell expansion and organ growth. EB proteins are viewed as central regulators of +TIPs and cell polarity in animals; SPR1 homologs are specific to plants. To explore if EB1b and SPR1 fundamentally function together, we combined genetic, biochemical, and cell imaging approaches in Arabidopsis thaliana. We found that eb1b-2 spr1-6 double mutant roots exhibit substantially more severe polar expansion defects than either single mutant, undergoing right-looping growth and severe axial twisting instead of waving on tilted hard-agar surfaces. Protein interaction assays revealed that EB1b and SPR1 bind each other and tubulin heterodimers, which is suggestive of a microtubule loading mechanism. EB1b and SPR1 show antagonistic association with microtubules in vitro. Surprisingly, our combined analyses revealed that SPR1 can load onto microtubules and function independently of EB1 proteins, setting SPR1 apart from most studied +TIPs in animals and fungi. Moreover, we found that the severity of defects in microtubule dynamics in spr1 eb1b mutant hypocotyl cells correlated well with the severity of growth defects. These data indicate that SPR1 and EB1b have complex interactions as they load onto microtubule plus ends and direct polar cell expansion and organ growth in response to directional cues.     

A pivotal heme-transfer reaction intermediate in cytochrome c biogenesis

c-Type cytochromes are widespread proteins, fundamental for respiration or photosynthesis in most cells. They contain heme covalently bound to protein in a highly conserved, highly stereospecific post-translational modification. In many bacteria, mitochondria, and archaea this heme attachment is catalyzed by the cytochrome c maturation (Ccm) proteins. Here we identify and characterize a covalent, ternary complex between the heme chaperone CcmE, heme, and cytochrome c. Formation of the complex from holo-CcmE occurs in vivo and in vitro and involves the specific heme-binding residues of both CcmE and apocytochrome c. The enhancement and attenuation of the amounts of this complex correlates completely with known consequences of mutations in genes for other Ccm proteins. We propose the complex is a trapped catalytic intermediate in the cytochrome c biogenesis process, at the point of heme transfer from CcmE to the cytochrome, the key step in the maturation pathway.     

Do established SNPs affecting bovine milk traits exist in other dairy ruminants?

To assess whether established single nucleotide polymorphisms (SNPs) affecting bovine milk traits are present in small ruminants, we genotyped samples from Chios and Cyprus fat-tailed sheep, as well as Damascus and Machaeras goats for the presence of the acylCoA:diacylglycerol acyltransferase 1 (DGAT1) K232A and the growth hormone receptor (GHR) F279Y SNPs. Both of these SNPs have been previously well documented in cattle as having strong effects on milk yield and composition and have been postulated as being the causative mutations to partially explain QTLs identified on bovine chromosomes 14 and 20. Although we were able to confirm the presence of both of these mutations in bovine sample controls by both allele specific PCR reactions and direct DNA sequencing, we were unable to detect them in any of the four major pure breeds of sheep and goats supporting the dairy industry of Cyprus.     

Oral supplementation with l-aspartate and l-glutamate inhibits atherogenesis and fatty liver disease in cholesterol-fed rabbit

Previous studies have shown that dietary supplementation with l-aspartate and l-glutamate inhibits fatty streak initiation in cholesterol-fed rabbit. The present study investigates the role of dicarboxylic amino acids on the progression of fatty streaks and the development of fatty liver disease, which were caused in New Zealand White rabbits after a 0.5% w/w cholesterol diet for 7 weeks. A group of animals additionally received a combination of 12.5 mM l-aspartate and 12.5 mM l-glutamate per day through drinking water. Total cholesterol (TC), high-density lipoproteins cholesterol (HDLC), non-HDLC and triacylglycerol (TAG) concentrations were measured in plasma. Serum gamma-glutamyl transferase (γ-GT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were also determined. At the end of dietary intervention, animals were sacrificed. Aortic, hepatic and brain lesions were evaluated after staining with hematoxylin and eosin. Supplementation with dicarboxylic amino acids inhibited the progression of aortic intima thickness (P < 0.05) and the development of liver lesions (P < 0.05). TC, non-HDLC and TAG were similarly increased in both cholesterol-fed groups. Serum γ-GT and AST activities elevated during the study in all cholesterol-fed animals but the elevation of γ-GT was milder and significantly lower in rabbits treated with l-aspartate and l-glutamate (P < 0.05). ALT activity was not affected by cholesterol feeding. In conclusion, oral supplementation with l-aspartate and l-glutamate inhibits the progression of atherogenesis and the development of fatty liver disease in the animal model of cholesterol-fed rabbit. The beneficial effects of dicarboxylic amino acids reflect the limited elevation of serum γ-GT activity.     

The role of the pro-apoptotic protein Siva in the pathogenesis of Familial Mediterranean fever: A structural and functional analysis

Familial Mediterranean fever (FMF) is an autosomal, recessive disease, attributed to mutations in MEFV gene encoding pyrin, which is characterized by recurrent, acute and self-limiting attacks of fever as well as an increased neutrophil and monocyte apoptosis. Most disease-associated mutations in MEFV gene reside on the C-terminal PRYSPRY (B30.2) domain of pyrin, an area found to interact with the pro-apoptotic protein Siva. Because apoptotic events may be contributing to endogenous inflammation we hypothesized that mutations in pyrin may affect Siva-mediated apoptosis. The confirmation of this hypothesis would be of a great biological significance since it would be demonstrated a connection between apoptosis and inflammation. We used homology modeling to construct a 3-D model of Siva protein and the constructed model of Siva defined structural elements with potential of binding other proteins to induce apoptosis. Given that Siva protein binds pyrin as shown by transfection and immunoprecipitation experiments, apoptosis was assessed by FACS and Western blotting. No differences in rates of apoptosis in myeloid cells (THP-1) upon transfection with either wt pyrin or mutant forms of pyrin were found. Patients with FMF did not display any mutations in the Siva-1 (full length) gene. Siva-1 was not linked to pyrin in the major predicted FMF gene network constructed using a literature-curated gene signature for FMF. These results suggest that Siva-mediated unprovoked apoptosis is not likely to be involved in the pathogenesis of FMF.     

Significance of immunocytochemical expression of E-cadherin, N-cadherin and CD44 in serous effusions using liquid-based cytology

OBJECTIVE: To assess the diagnostic utility of E-cadherin (E-cad), N-cadherin (N-cad) and CD44 to discriminate adenocarcinoma cells from benign and malignant mesothelial cells in body cavity fluids and to clarify the origin of cancer cells. STUDY DESIGN: A total of 120 ThinPrep (Cytyc Corp., Boxborough, Massachusetts, U.S.A.) cytologic specimens of serous effusions, which included 22 cases of reactive mesothelium, 6 cases of malignant mesothelioma and 92 cases of metastatic adenocarcinoma from various sites, were immunostained for E-cad, N-cad and CD44. RESULTS: Eighty-three of 92 metastatic adenocarcinomas (90.21%) expressed E-cad, while 1 of 6 malignant mesotheliomas and 1 of 22 cases of reactive mesothelium were positive for E-cad. All 6 cases of mesothelioma expressed N-cad, whereas most cases of metastatic adenocarcinomas were negative. CD44 immunoreactivity was seen in 18 of 22 (81.81%) benign effusions and in 21 of 92 (22.82%) metastatic adenocarcinomas. CONCLUSION: The combination of E-cad, N-cad and CD44 appears to be a useful panel for distinguishing metastatic adenocarcinoma, mesothelioma and reactive mesothelium and also for clarifying the exact histogenetic origin of cancer cells. This is of great importance in a few otherwise-insoluble cases because of differences in tumor treatment and prognosis.