Increased arginine-vasopressin response to hypertonic stimulation and upright posture in idiopathic hyperprolactinemia

To evaluate the possible influence of idiopathic hyperprolactinemia on the arginine-vasopressin (AVP) response to osmotic and pressure-volumetric stimuli, 14 idiopathic hyperprolactinemic women and 13 normoprolactinemic women were studied during a hypertonic saline infusion test (0.51M NaCl infusion for 2h) and an orthostatic test (standing upright and maintaining an orthostatic position for 20min). In both experimental conditions, the AVP response was significantly higher in women with idiopathic hyperprolactinemia than in normal normoprolactinemic women. These results indicate that in women hyperprolactinemia influences the AVP response to hyperosmotic and hypovolemic stimuli.     

Proteomic identification of differentially expressed proteins in the anoxic rice coleoptile

Rice is the staple food for more than fifty percent of the world's population, and is therefore an important crop. However, its production is hindered by several biotic and abiotic stresses. Although rice is the only crop that can germinate even in the complete absence of oxygen (i.e. anoxia), flooding (low oxygen) is one of the major causes of reduced rice production. Rice germination under anoxia is characterized by the elongation of the coleoptile, but leaf growth is hampered. In this work, a comparative proteomic approach was used to detect and identify differentially expressed proteins in the anoxic rice coleoptile compared to the aerobic coleoptile. Thirty-one spots were successfully identified by MALDI-TOF MS analysis. The majority of the identified proteins were related to stress responses and redox metabolism. The expression levels of twenty-three proteins and their respective mRNAs were analyzed in a time course experiment.     

Quantitative role of shrimp fecal bacteria in organic matter fluxes in a recirculating shrimp aquaculture system

Microorganisms play integral roles in the cycling of carbon (C) and nitrogen (N) in recirculating aquaculture systems (RAS) for fish and shellfish production. We quantified the pathways of shrimp fecal bacterial activities and their role in C- and N-flux partitioning relevant to culturing Pacific white shrimp, Penaeus (Litopenaeus) vannamei, in RAS. Freshly produced feces from P. vannamei contained 0.6-7 × 10(10) bacteria g(-1) dry wt belonging to Bacteroidetes (7%), Alphaproteobacteria (4%), and, within the Gammaproteobacteria, almost exclusively to the genus Vibrio (61%). Because of partial disintegration of the feces (up to 27% within 12 h), the experimental seawater became inoculated with fecal bacteria. Bacteria grew rapidly in the feces and in the seawater, and exhibited high levels of aminopeptidase, chitinase, chitobiase, alkaline phosphatase, α- and β-glucosidase, and lipase activities. Moreover, fecal bacteria enriched the protein content of the feces within 12 h, potentially enriching the feces for the coprophagous shrimp. The bacterial turnover time was much faster in feces (1-10 h) than in mature RAS water (350 h). Thus, shrimp fecal bacteria not only inoculate RAS water but also contribute to bacterial abundance and productivity, and regulate system processes important for shrimp health.     

Stanniocalcin 1 affects redox status of swine granulosa cells

Stanniocalcin 1 (STC1) is a glycoprotein hormone expressed in different mammalian tissues. In previous studies, we showed STC1 expression in swine ovarian follicles and we demonstrated that STC1 may be a physiological regulator of follicular function. Since reactive oxygen species (ROS) are important signal transducers in the ovary, the present study was undertaken to investigate STC1 action on ROS generation and on the activity of the major enzymatic and non-enzymatic scavengers in swine granulosa cells. O(2)- generation, catalase activity and FRAP levels were increased by STC1, whereas H(2)O(2) generation and peroxidase activity were decreased by STC1. Taken together, our data show that STC1 modulates redox status in swine granulosa cells.     

Structural analysis in nonsymbiotic hemoglobins: What can we learn from inner cavities?

Plants contain three classes of hemoglobins which are not associated with nitrogen fixing bacteria, and have been accordingly termed nonsymbiotic hemoglobins. The function of nonsymbiotic hemoglobins is as yet mostly unknown. A NO dioxygenase activity has been proposed and demonstrated for some of them in vitro. In this context, a sound molecular mechanism that relates the structure with the biological activity is crucial to suggest a given physiological role. Insight into such a mechanism is now facilitated by recent progress made in both experimental and computational techniques. These studies have highlighted a number of key structural features implicated in the function of nonsymbiotic hemoglobins. The bis-histidyl hexacoordination of the heme in both its ferric and ferrous states provides a powerful and general tool to modulate reactivity, protein dynamics, and shape of the cavities. In addition, the specific arrangement of distal cavity residues provides effective protection against autoxidation. Inspection of the static crystal structures available for both liganded and unliganded states seems unsufficient to explain the function of these proteins. Function appears to be intimately linked with protein flexibility, which influences the dynamical behavior of inner cavities, capable of delivering apolar reactants to the reaction site, and removing charged reaction products. In this mini review, we demonstrate how the integration of information derived from experimental assays and computational studies is valuable and can shed light into the linkage between structural plasticity of nonsymbiotic hemoglobins and their biological role.     

Mitochondrial BCL-2 inhibits AMBRA1-induced autophagy

BECLIN 1 is a central player in macroautophagy. AMBRA1, a BECLIN 1-interacting protein, positively regulates the BECLIN 1-dependent programme of autophagy. In this study, we show that AMBRA1 binds preferentially the mitochondrial pool of the antiapoptotic factor BCL-2, and that this interaction is disrupted following autophagy induction. Further, AMBRA1 can compete with both mitochondrial and endoplasmic reticulum-resident BCL-2 (mito-BCL-2 and ER-BCL-2, respectively) to bind BECLIN 1. Moreover, after autophagy induction, AMBRA1 is recruited to BECLIN 1. Altogether, these results indicate that, in normal conditions, a pool of AMBRA1 binds preferentially mito-BCL-2; after autophagy induction, AMBRA1 is released from BCL-2, consistent with its ability to promote BECLIN 1 activity. In addition, we found that the binding between AMBRA1 and mito-BCL-2 is reduced during apoptosis. Thus, a dynamic interaction exists between AMBRA1 and BCL-2 at the mitochondria that could regulate both BECLIN 1-dependent autophagy and apoptosis.     

The link between the PDL1 costimulatory pathway and Th17 in fetomaternal tolerance

Fetomaternal tolerance has been shown to depend both on regulatory T cells (Tregs) and negative signals from the PD1-PDL1 costimulatory pathway. More recently, IL-17-producing T cells (Th17) have been recognized as a barrier in inducing tolerance in transplantation. In this study, we investigate the mechanisms of PDL1-mediated regulation of fetomaternal tolerance using an alloantigen-specific CD4(+) TCR transgenic mouse model system (ABM-tg mouse). PDL1 blockade led to an increase in embryo resorption and a reduction in litter size. This was associated with a decrease in Tregs, leading to a lower Treg/effector T cell ratio. Moreover, PDL1 blockade inhibited Ag-specific alloreactive T cell apoptosis and induced apoptosis of Tregs and a shift toward higher frequency of Th17 cells, breaking fetomaternal tolerance. These Th17 cells arose predominantly from CD4(+)Foxp3(-) cells, rather than from conversion of Tregs. Locally in the placenta, similar decrease in regulatory and apoptotic markers was observed by real-time PCR. Neutralization of IL-17 abrogated the anti-PDL1 effect on fetal survival rate and restored Treg numbers. Finally, the adoptive transfer of Tregs was also able to improve fetal survival in the setting of PDL1 blockade. This is to our knowledge the first report using an alloantigen-specific model that establishes a link between PDL1, Th17 cells, and fetomaternal tolerance.     

Palytoxin Induces Functional Changes of Anion Transport in Red Blood Cells: Metabolic Impact

Palytoxin (PTX) is classified as one of the most powerful marine biotoxins (of high molecular weight and no protein origin) because it is able to interact strongly with important cellular structures influencing their function in different biological processes. This study of the effects of PTX on red blood cells (RBC) extends the knowledge about its toxicity, which concerns not only the well-known action on Na(+)/K(+)-ATPase but also band 3 protein (B3 or AE1), the role of which is essential for anion transport and for the structure, function, and metabolic integrity of the erythrocyte. The effects of PTX on RBC can be summarized as follows: it alters the anionic flux and seriously compromises not only CO(2) transport but also the metabolic modulation centered on the oxy-deoxy cycle of hemoglobin; it stabilizes the plasma membrane by preventing lipid peroxidation; and its effect does not lead to activation of caspases 3 and 8. From what is reported in steps 2 and 3, and on the basis of the results obtained on hemolysis, methemoglobin levels, and phosphatase activity, an increase of the reducing power of the erythrocytes (RBC) in the presence of PTX clearly emerges. The results have enabled us to outline some metabolic adaptations induced in the RBC by PTX.