Alcohol:NAD oxidoreductase in brain of rats from a colony fed dilute ethanol for many generations.

—Alcohol:NAD oxidoreductase (EC 1.1.1.1) was studied in brain cortex, hypothalamus, cerebellum and midbrain of adult and immature rats, and in the whole encephalon of neonatal rats. The rats used in this study were (i) from a colony which has been given 12% (v/v) aqueous ethanol as the only fluid for 54 generations (‘E.F.’ rats); (ii) rats removed from this colony after the forty-eighth generation and thereafter fed water instead of the alcohol solution (‘E.F./H₂O’ rats); and (iii) normal rats. Enzyme activity in the 20,000 g supernatant of tissue homogenates was measured by the method of Raskin and Sokoloff. Activity was found to be highest in neonatal rat brain and to decrease as the age increased. Activity in the hypothalamus of adult E.F. rats was significantly higher than that found in the same region of adult E.F./H₂O rats. Immature rat cerebellum alcohol:NAD oxidoreductase activity was higher both in ‘E.F.’ and ‘E.F./H₂O’ suggesting a possible genetic change be involved in this CNS region. It may be concluded that, with the exception of neonatal rats, ethanol consumption induces an increase in rat CNS alcohol :NAD oxidoreductase activity.     

Evidence for Chronic Low-Grade Systemic Inflammation in Individuals with Agoraphobia from a Population-Based Prospective Study

Background

Anxiety disorders have been linked to an increased risk of incident coronary heart disease in which inflammation plays a key pathogenic role. To date, no studies have looked at the association between proinflammatory markers and agoraphobia.

Methods

In a random Swiss population sample of 2890 persons (35-67 years, 53% women), we diagnosed a total of 124 individuals (4.3%) with agoraphobia using a validated semi-structured psychiatric interview. We also assessed socioeconomic status, traditional cardiovascular risk factors (i.e., body mass index, hypertension, blood glucose levels, total cholesterol/high-density lipoprotein-cholesterol ratio), and health behaviors (i.e., smoking, alcohol consumption, and physical activity), and other major psychiatric diseases (other anxiety disorders, major depressive disorder, drug dependence) which were treated as covariates in linear regression models. Circulating levels of inflammatory markers, statistically controlled for the baseline demographic and health-related measures, were determined at a mean follow-up of 5.5 ± 0.4 years (range 4.7 – 8.5).

Results

Individuals with agoraphobia had significantly higher follow-up levels of C-reactive protein (p = 0.007) and tumor-necrosis-factor-α (p = 0.042) as well as lower levels of the cardioprotective marker adiponectin (p = 0.032) than their non-agoraphobic counterparts. Follow-up levels of interleukin (IL)-1β and IL-6 did not significantly differ between the two groups.

Conclusions

Our results suggest an increase in chronic low-grade inflammation in agoraphobia over time. Such a mechanism might link agoraphobia with an increased risk of atherosclerosis and coronary heart disease, and needs to be tested in longitudinal studies.     

Compromised proteasome degradation elevates neuronal nitric oxide synthase levels and induces apoptotic cell death

The significance of impairment of proteasome activity in PC12 cells was examined in connection with nitrative/nitrosative stress and apoptotic cell death. Treatment of differentiated PC12 cells with MG132, a proteasome inhibitor, elicited a dose- and time-dependent increase in neuronal nitric oxide synthase (nNOS) protein levels, decreased cell viability, and increased cytotoxicity. Viability and cytotoxicity were ameliorated by L-NAME (a broad NOS inhibitor). Nitric oxide/peroxynitrite formation was increased upon treatment of PC12 cells with MG132 and decreased upon treatment with the combination of MG132 and 7-NI (a specific inhibitor of nNOS). The decreases in cell viability appeared to be effected by an activation of JNK and its effect on mitochondrial Bcl-x_L phosphorylation. These effects are strengthened by the activation of caspase-9 along with increased caspase-3 activity upon treatment of PC12 cells with MG132. These results suggest that impairment of proteasome activity and consequent increases in nNOS levels lead to a nitrative stress that involves the coordinated response of JNK cytosolic signaling and mitochondrion-driven apoptotic pathways.     

Desarrollo global del niño: más allá de la suplementación farmacológica con yodo

Iodine deficiency is a factor that may compromise child development, but is not the only one. Other health determinants, some of them outside the healthcare system, are able to influence development. Fighting iodine deficiency may be a pragmatic and useful strategy if it is found to be not maleficent, beneficial to health, and cost-effective, and does not make us lose the notion that child development goes beyond psychomotor or cognitive performance. This article analyzes such constraints from a critical point of view.     

<Emphasis Type="Italic">Trichomonas vaginalis</Emphasis> metalloproteinase TvMP50 is a monomeric Aminopeptidase P-like enzyme

Previously, metalloproteinase was isolated and identified from Trichomonas vaginalis, belonging to the aminopeptidase P-like metalloproteinase subfamily A/B, family M24 of clan MG, named TvMP50. The native and recombinant TvMP50 showed proteolytic activity, determined by gelatin zymogram, and a 50 kDa band, suggesting that TvMP50 is a monomeric active enzyme. This was an unexpected finding since other Xaa-Pro aminopeptidases/prolidases are active as a biological unit formed by dimers/tetramers. In this study, the evolutionary history of TvMP50 and the preliminary crystal structure of the recombinant enzyme determined at 3.4 Å resolution is reported. TvMP50 was shown to be a type of putative, eukaryotic, monomeric aminopeptidase P, and the crystallographic coordinates showed a monomer on a “pseudo-homodimer” array on the asymmetric unit that resembles the quaternary structure of the M24B dimeric family and suggests a homodimeric aminopeptidase P-like enzyme as a likely ancestor. Interestingly, TvMP50 had a modified N-terminal region compared with other Xaa-Pro aminopeptidases/prolidases with three-dimensional structures; however, the formation of the standard dimer is structurally unstable in aqueous solution, and a comparably reduced number of hydrogen bridges and lack of saline bridges were found between subunits A/B, which could explain why TvMP50 portrays monomeric functionality. Additionally, we found that the Parabasalia group contains two protein lineages with a “pita bread” fold; the ancestral monomeric group 1 was probably derived from an ancestral dimeric aminopeptidase P-type enzyme, and group 2 has a probable dimeric kind of ancestral eukaryotic prolidase lineage. The implications of such hypotheses are also presented.     

Presence of the dinoflagellates Ceratium dens, C. fusus and C. furca (Gonyaulacales: Ceratiaceae) in Golfo de Nicoya, Costa Rica

Harmful Algae Blooms (HAB) are a frequent phenomenon in the Gulf of Nicoya, Costa Rica, as in other parts of the world. The morphology and physiology of these microalgae are important because HAB species have adaptive characteristics. The production of high concentrations of paralytic toxins by Ceratium dinoflagellates has only been documented at the experimental level. However, this genus has been associated with the mortality of aquatic organisms, including oyster and shrimp larva, and fish, and with decreased water quality. Recently, fishermen reported massive mortality of encaged fish near Tortuga Island (Gulf of Nicoya). Samples were taken from an algal bloom that had produced an orange coloration and had a strong foul-smelling odor. Ultrastructural details were examined with scanning electron microscopy. The dinoflagellates Ceratium dens, C. furca and C. fusus were found in samples taken at the surface. The cell count revealed four million cells of this genus per liter. The morphological variability of these species is high; therefore electron microscopy is an useful tool in the ultrastructural study of these organisms. This is the first time that three Ceratium species are reported concurrently producing harmful blooms in Costa Rica.     

Sensitive genome-wide screen for low secondary enzymatic activities: the YjbQ family shows thiamin phosphate synthase activity

Contemporary enzymes are highly efficient and selective catalysts. However, due to the intrinsically very reactive nature of active sites, gratuitous secondary reactions are practically unavoidable. Consequently, even the smallest cell, with its limited enzymatic repertoire, has the potential to carry out numerous additional, very likely inefficient, secondary reactions. If selectively advantageous, secondary reactions could be the basis for the evolution of new fully functional enzymes. Here, we investigated if Escherichia coli has cryptic enzymatic activities related to thiamin biosynthesis. We selected this pathway because this vitamin is essential, but the cell's requirements are very small. Therefore, enzymes with very low activity could complement the auxotrophy of strains deleted of some bona fide thiamin biosynthetic genes. By overexpressing the E. coli's protein repertoire, we selected yjbQ, a gene that complemented a strain deleted of the thiamin phosphate synthase (TPS)-coding gene thiE. In vitro studies confirmed TPS activity, and by directed evolution experiments, this activity was enhanced. Structurally oriented mutagenesis allowed us to identify the putative active site. Remote orthologs of YjbQ from Thermotoga, Sulfolobus, and Pyrococcus were cloned and also showed thiamin auxotrophy complementation, indicating that the cryptic TPS activity is a property of this protein family. Interestingly, the thiE- and yjbQ-coded TPSs are analog enzymes with no structural similarity, reflecting distinct evolutionary origin. These results support the hypothesis that the enzymatic repertoire of a cell such as E. coli has the potential to perform vast amounts of alternative reactions, which could be exploited to evolve novel or more efficient catalysts.     

Protein kinase D1 inhibition interferes with mitosis progression

Protein kinase D1 (PKD1) plays a vital role in signal transduction, cell proliferation, membrane trafficking, and cancer; however, the majority of the studies up to date had centered primarily on PKD1 functions in interphase, very little is known about its role during cell division. We previously demonstrated that during mitosis PKD1 is activated and associated with centrosomes, spindles, and midbodies. However, these observations did not address whether PKD1 was associated with mitosis regulation. Accordingly, we used rapidly acting PKD-specific inhibitors to examine the contribution of PKD1 the sequence of events in mitosis. We found that although PKD1 overexpression did not affect mitosis progression, suppression of its catalytic activity by two structurally unrelated inhibitors (kb NB 142-70 and CRT 0066101) induced a significant delay in metaphase to anaphase transition time. PKD1 inhibition during mitosis also produced the appearance of abnormal spindles, defects in chromosome alignment, and segregation as well as apoptosis. Thus, these observations indicate that PKD1 activity is associated with mitosis regulation.