Central NPY-Y5 receptors activation plays a major role in fasting-induced pituitary-thyroid axis suppression in adult rat

Neuropeptide Y (NPY) inhibits TRH neurons in fed state, and hypothalamic NPY higher expression during fasting has been proposed to be involved in fasting-induced suppression of the hypothalamus-pituitary-thyroid (HPT) axis. We investigated the role of central Y5 receptors in the control of thyrotropin (TSH) and thyroid hormone (TH) secretion. Fed and fasting rats received twice daily central injections (3rd ventricle) of Y5 receptor antagonist (CGP71683; 15nmol/rat) for 72h. Fasted rats also received a single central injection of CGP71683 (15nmol/rat) at the end of 72h of fasting. In fed rats, Y5 receptor blockade reduced total food intake by 32% and body mass by almost 10% (p<0.01), corroborating the role of this receptor in food intake control. 72h-fasted rats exhibited a 4-fold increase in serum TSH (p<0.001), 1h after a single injection of Y5 antagonist. Also with multiple injections during 72h of fasting, Y5 blockade resulted in activation of thyroid axis, as demonstrated by a 3-times rise in serum T4 (p<0.001), accompanied by unchanged TSH and T3. In fed rats, the chronic central administration of CGP71683 resulted in reduced total serum T4 without changes in free T4 and TSH. Serum leptin and PYY were not altered by the NPY central blockade in both fed and fasted rats, suggesting no role of these hormones in the alterations observed. Therefore, the inhibition of central Y5 neurotransmission resulted in activation of thyroid axis during fasting suggesting that NPY-Y5 receptors contribute to fasting-induced TSH and TH suppression.     

The functional traits of host fish can act as good predictors for parasite composition in a neotropical floodplain

Parasite diversity can be influenced by the interaction of environmental factors and host traits, but understanding which traits can be decisive for the establishment of the parasite may provide subsidies for a better understanding of the host-parasite relationship. In this study, we investigated whether functional traits, diet, and host phylogeny can predict the similarity of the endoparasite composition of a fish assemblage in a Brazilian floodplain. Of the three evaluated components, the host's diet was the factor that showed the greatest influence on the composition and similarity of endoparasites, demonstrating the highest value of the explanation. The functional traits and phylogeny, despite presenting significant values (unique effect and global effect), showed low explainability in the composition of the endoparasites. When analyzing the joint effects, all components showed significant influence. Hosts that live in the same environment that are phylogenetically related and have a similar ecology have a certain degree of homogeneity in their parasite assemblages and, because they are endoparasites (which are acquired trophically along the chain), diet is the main driver of parasite richness and similarity. Overall, host traits can be one of the main determinants of parasite composition, so studies that address the functional traits of the host provide a representation of local diversity and define the possible patterns of these parasite communities.     

c-FLIP regulates autophagy by interacting with Beclin-1 and influencing its stability

c-FLIP (cellular FLICE-like inhibitory protein) protein is mostly known as an apoptosis modulator. However, increasing data underline that c-FLIP plays multiple roles in cellular homoeostasis, influencing differently the same pathways depending on its expression level and isoform predominance. Few and controversial data are available regarding c-FLIP function in autophagy. Here we show that autophagic flux is less effective in c-FLIP−/− than in WT MEFs (mouse embryonic fibroblasts). Indeed, we show that the absence of c-FLIP compromises the expression levels of pivotal factors in the generation of autophagosomes. In line with the role of c-FLIP as a scaffold protein, we found that c-FLIP_L interacts with Beclin-1 (BECN1: coiled-coil, moesin-like BCL2-interacting protein), which is required for autophagosome nucleation. By a combination of bioinformatics tools and biochemistry assays, we demonstrate that c-FLIP_L interaction with Beclin-1 is important to prevent Beclin-1 ubiquitination and degradation through the proteasomal pathway. Taken together, our data describe a novel molecular mechanism through which c-FLIP_L positively regulates autophagy, by enhancing Beclin-1 protein stability.Subject terms: Biochemistry, Autophagy     

In vitro Biological Activities of Seed Essential Oils from the Cameroonian Spices Afrostyrax lepidophyllus Mildbr. and Scorodophloeus zenkeri Harms Rich in Sulfur‐Containing Compounds

The chemical composition of the essential oils obtained from the seeds of bush onion (Afrostyrax lepidophyllus) and tropical garlic tree (Scorodophloeus zenkeri), plants used as spices in the traditional African cuisine, was determined by GC‐FID and GC/MS analyses. Moreover, in vitro biological properties of the oils, namely, the cytotoxic, antioxidant, and antimicrobial activities, were investigated by the MTT, the DPPH^. and ABTS^.+ scavenging, and the agar disc‐diffusion methods, respectively. Both oils were composed mainly by S‐containing compounds, accounting for 91.0–96.1% of the total oil compositions, which provided them the typical garlic‐ and onion‐like odors of spices. The predominant compound in both oils, 2,4,5,7‐tetrathiaoctane ( 1 ; 51.5–52.9%), was isolated by preparative TLC and structurally elucidated by ¹H‐ and ¹³C‐NMR data. The oils exhibited a strong inhibitory effect on the growth of human cancer cells, namely, T98G (human glioblastoma multiforme cell line), MDA‐MB 231 (human breast adenocarcinoma cell line), A375 (human malignant melanoma cell line), and HCT116 (human colon carcinoma cell line) cells, and a good DPPH^.‐ and ABTS^.+‐scavenging activity, while the antimicrobial effects were negligible. The volatile compositions of A. lepidophyllus and S. zenkeri oils supported their use as odorous spices. The significant inhibition activities detected make these oils worthy of further investigation as promising chemopreventive agents to be exploited in the African pharmaceutical market.     

Probiotic Properties of Lactic Acid Bacteria Isolated from Water-Buffalo Mozzarella Cheese

This study evaluated the probiotic properties (stability at different pH values and bile salt concentration, auto-aggregation and co-aggregation, survival in the presence of antibiotics and commercial drugs, study of β-galactosidase production, evaluation of the presence of genes encoding MapA and Mub adhesion proteins and EF-Tu elongation factor, and the presence of genes encoding virulence factor) of four LAB strains (Lactobacillus casei SJRP35, Leuconostoc citreum SJRP44, Lactobacillus delbrueckii subsp. bulgaricus SJRP57 and Leuconostoc mesenteroides subsp. mesenteroides SJRP58) which produced antimicrobial substances (antimicrobial peptides). The strains survived the simulated GIT modeled in MRS broth, whole and skim milk. In addition, auto-aggregation and the cell surface hydrophobicity of all strains were high, and various degrees of co-aggregation were observed with indicator strains. All strains presented low resistance to several antibiotics and survived in the presence of commercial drugs. Only the strain SJRP44 did not produce the β-galactosidase enzyme. Moreover, the strain SJRP57 did not show the presence of any genes encoding virulence factors; however, the strain SJRP35 presented vancomycin resistance and adhesion of collagen genes, the strain SJRP44 harbored the ornithine decarboxylase gene and the strain SJRP58 generated positive results for aggregation substance and histidine decarboxylase genes. In conclusion, the strain SJRP57 was considered the best candidate as probiotic cultures for further in vivo studies and functional food products development.     

Leuconostoc mesenteroides SJRP55: A Bacteriocinogenic Strain Isolated from Brazilian Water Buffalo Mozzarella Cheese

The production of bacteriocins by Leuconostoc mesenteroides represents an important opportunity for exploration of their potential use for industrial purpose. The antimicrobial compounds produced by L. mesenteroides subsp. mesenteroides SJRP55 strain were characterized and purified. Cell-free supernatant of Leuc. mesenteroides subsp. mesenteroides SJRP55 produced antibacterial compounds against Listeria spp. strains and not inhibiting against Lactobacillus spp. The antimicrobial substances were stable at high temperatures (100 °C for 2 h and 121 °C for 20 min) and low pH (pH 2–4) values, but sensitive to proteolytic enzymes and resistant to α-amylase, lipase and catalase enzymes. The optimal temperature for active peptides production was 25 °C. The antimicrobial compounds were purified by ammonium sulfate precipitation, affinity column and reverse-phase chromatography. Mass spectrometry and amino acids analyses showed that the bacteriocins were identical to mesentericin Y105 and B105. The producer strain’s DNA analysis revealed presence of open reading frames possibly coding for virulence factors, such as enterococcal surface protein (esp), collagen adhesion (ace) and intrinsic vancomycin resistance (vanA); however, biogenic amines encoding genes were not observed. Leuc. mesenteroides subsp. mesenteroides SJRP55 is a promising biopreservative culture in fermented milk, and the purified bacteriocins can also be applied in food preservation.     

Life Course Socioeconomic Position and C-Reactive Protein: Mediating Role of Health-Risk Behaviors and Metabolic Alterations. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Background

Chronic inflammation has been postulated to be one mediating mechanism explaining the association between low socioeconomic position (SEP) and cardiovascular disease (CVD). We sought to examine the association between life course SEP and C-reactive protein (CRP) levels in adulthood, and to evaluate the extent to which health-risk behaviors and metabolic alterations mediate this association. Additionally, we explored the possible modifying influence of gender.

Methods and Findings

Our analytical sample comprised 13,371 participants from ELSA-Brasil baseline, a multicenter prospective cohort study of civil servants. SEP during childhood, young adulthood, and adulthood were considered. The potential mediators between life course SEP and CRP included clusters of health-risk behaviors (smoking, low leisure time physical activity, excessive alcohol consumption), and metabolic alterations (obesity, hypertension, low HDL, hypertriglyceridemia, and diabetes). Linear regression models were performed and structural equation modeling was used to evaluate mediation. Although lower childhood SEP was associated with higher levels of CRP in adult life, this association was not independent of adulthood SEP. However, CRP increased linearly with increasing number of unfavorable social circumstances during the life course (p trend <0.001). The metabolic alterations were the most important mediator between cumulative SEP and CRP. This mediation path accounted for 49.5% of the total effect of cumulative SEP on CRP among women, but only 20.2% among men. In consequence, the portion of the total effect of cumulative SEP on CRP that was mediated by risk behaviors and metabolic alterations was higher among women (55.4%) than among men (36.8%).

Conclusions

Cumulative SEP across life span was associated with elevated systemic inflammation in adulthood. Although health-risk behaviors and metabolic alterations were important mediators of this association, a sizable fraction of this association was not mediated by these factors, suggesting that other pathways might play a role, especially among men.     

The Cratylia mollis Seed Lectin Induces Membrane Permeability Transition in Isolated Rat Liver Mitochondria and a Cyclosporine A‐Insensitive Permeability Transition in Trypanosoma cruzi Mitochondria

Previous results provided evidence that Cratylia mollis seed lectin (Cramoll 1,4) promotes Trypanosoma cruzi epimastigotes death by necrosis via a mechanism involving plasma membrane permeabilization to Ca²⁺ and mitochondrial dysfunction due to matrix Ca²⁺ overload. In order to investigate the mechanism of Ca²⁺‐induced mitochondrial impairment, experiments were performed analyzing the effects of this lectin on T. cruzi mitochondrial fraction and in isolated rat liver mitochondria (RLM), as a control. Confocal microscopy of T. cruzi whole cell revealed that Cramoll 1,4 binding to the plasma membrane glycoconjugates is followed by its internalization and binding to the mitochondrion. Electrical membrane potential (?Ψ_m) of T. cruzi mitochondrial fraction suspended in a reaction medium containing 10 μM Ca²⁺ was significantly decreased by 50 μg/ml Cramoll 1,4 via a mechanism insensitive to cyclosporine A (CsA, membrane permeability transition (MPT) inhibitor), but sensitive to catalase or 125 mM glucose. In RLM suspended in a medium containing 10 μM Ca²⁺ this lectin, at 50 μg/ml, induced increase in the rate of hydrogen peroxide release, mitochondrial swelling, and ?Ψ_m disruption. All these mitochondrial alterations were sensitive to CsA, catalase, and EGTA. These results indicate that Cramoll 1, 4 leads to inner mitochondrial membrane permeabilization through Ca²⁺ dependent mechanisms in both mitochondria. The sensitivity to CsA in RLM characterizes this lectin as a MPT inducer and the lack of CsA effect identifies a CsA‐insensitive MPT in T. cruzi mitochondria.