The hypothalamic–hypophyseal–gonadal regulation of hepatic glutathione S-transferases in the rat

Hepatic glutathione S-transferase activities were determined with the substrates 1,2-dichloro-4-nitrobenzene and 1-chloro-2,4-dinitrobenzene. Sexual differentiation of glutathione S-transferase activities is not evident during the prepubertal period, but glutathione conjugation with 1,2-dichloro-4-nitrobenzene is 2–3-fold greater in adult males than in females. Glutathione conjugation with 1-chloro-2,4-dinitrobenzene is slightly higher in adult males than adult females. No change in activity was observed after postpubertal gonadectomy of males or females. Neonatal castration of males results in a significant decrease in glutathione conjugation with 1,2-dichloro-4-nitrobenzene. Hypophysectomy, or hypophysectomy followed by gonadectomy did result in significantly higher glutathione S-transferase activities in both sexes. These increases can be reversed by implanting an adult male or female pituitary or four prepubertal pituitaries under the kidney capsule. Postpubertal sexual differentiation of glutathione S-transferase activities is neither dependent on pituitary sexual differentiation nor pituitary maturation. Prolactin concentrations are inversely related to glutathione S-transferase activities in hypophysectomized rats with or without ectopic pituitaries. Somatotropin exogenously administered to hypophysectomized rats results in decreased glutathione S-transferase activities, whereas prolactin has no effect. Adult male rats treated neonatally with monosodium l-glutamate to induce arcuate nucleus lesions of the hypothalamus have decreased glutathione S-transferase activities towards 1,2-dichloro-4-nitrobenzene and decreased somatotropin concentrations. Our experiments suggests that sexual differentiation of hepatic glutathione S-transferase is a result of a hypothalamic inhibiting factor in the male (absent in the female). This postpubertally expressed inhibiting factor acts on the pituitary to prevent secretion of a pituitary inhibiting factor (autonomously secreted by the female), resulting in higher glutathione S-transferase activities in the adult male than the adult female.     

Coexpression of two functional odor receptors in one neuron

One of the most fundamental tenets in the field of olfaction is that each olfactory receptor neuron (ORN) expresses a single odorant receptor. However, the one receptor-one neuron principle is difficult to establish rigorously. Here we construct a receptor-to-neuron map for an entire olfactory organ in Drosophila and find that two receptor genes are coexpressed in one class of ORN. Both receptors are functional in an in vivo expression system, they are only 16% identical in amino acid sequence, and the genes that encode them are unlinked. Most importantly, their coexpression has been conserved for >45 million years. Expression of multiple odor receptors in a cell provides an additional degree of freedom for odor coding.     

Selective actions of growth hormone on rat liver estrogen binding proteins

Levels of hepatic estrogen receptor were 9.0 ± 2.4 fmoles/mg cytosol protein in intact females compared to 3.4 ± 2.2 in hypophysectomized females. Likewise, levels of receptor were 9.8 ± 1.5 fmoles/mg cytosol protein in intact males and 2.7 ± 1.8 in hypophysectomized males. Hypophysectomy abolished the sex differences in a second class of binding sites termed higher capacity lower affinity binding sites by increasing female levels and decreasing male levels. Treatment of hypophysectomized male or female rats with growth hormone (2 units/kg body wt, two times daily) restored normal levels of hepatic estrogen receptor. Administration of growth hormone to hypophysectomized rats did not reverse the effects of hypophysectomy on higher capacity lower affinity binding sites. These studies demonstrate that growth hormone exerts selective actions on different forms of hepatic estrogen binding proteins.     

MEASURING RATES OF AMMONIUM ASSIMILATION IN MARINE ALGAE: USE OF THE PROTONOPHORE CARBONYL CYANIDE m-CHLOROPHENYLHYDRAZONE TO DISTINGUISH BETWEEN UPTAKE AND ASSIMILATION

A method for determining rates of ammonium assimilation in marine algae is described. Ammonium assimilation is defined as the decrease in total (medium + cellular) ammonium. The protonophore carbonyl cyanide m- chlorophenylhydrazone (CCCP) was used to distinguish between uptake and assimilation of ammonium. Ammonium uptake by nitrogen-replete and nitrogen-starved cells of the diatom Phaeodactylum tricornutum Bohlin and the green macroalga Enteromorpha sp. was completely (98%–99%) inhibited in the presence of 100 μM CCCP. In addition to inhibiting further uptake of ammonium, CCCP promoted the release of unassimilated ammonium by nitrogen-replete and nitrogen-starved P. tricornutum and Enteromorpha that had been allowed to take up ammonium for a period. Most (97.5%) of preaccumulated ¹⁴C-methylammonium was released by nitrogen-starved P. tricornutum in the presence of CCCP. Specific rates of ammonium assimilation in nitrogen-replete cultures of P. tricornutum were identical to the maximum growth rate, but specific rates in nitrogen-starved cultures were fourfold greater. Rates of ammonium assimilation in Enteromorpha during both the surge and the internally controlled uptake phases were the same as the internally controlled rate of uptake, suggesting that the latter is a reliable measure of the maximum rate of assimilation.     

Effect of a nutraceutical treatment on diabetic rats with targeted and CE-MS non-targeted approaches

Despite the introduction of hypoglycemic drugs, diabetes and related complications continue being a major medical problem. Diabetes long-term complications are not only related to the genesis of free radicals due to oxidation of glucose and to the non-enzymatic and progressive glycation of proteins but also to the endothelial dysfunction secondary to persistent hyperglycemia that causes cardiovascular complications. In an experimental model of streptozotocin (STZ) diabetic rats, the effect of five doses of an extract containing both an antioxidant (Rosmarinus officinalis) and folic acid were intragastrically administrated. Urine fingerprints of control and diabetic rats, both with and without treatment, were obtained by capillary electrophoresis with mass spectrometry (CE-TOF-MS). In order to have further biochemical knowledge of the effect, after treatment, rats were killed and plasma glucose, triglycerides, cholesterol, total protein, urea were analysed. Vitamin E in plasma and liver was also measured. Among the changes observed, the reduction in diuresis and plasma triglycerides, together with reduction in 2-aminobutyric, leucine/isoleucine, and dimethylglycine have shown that a short term nutraceutical treatment was able to reduce some of the complications in the STZ diabetic rats. In addition, this CE-MS metabolomic approach has permitted to identify metabolites related to metabolism of arginine, histidine, lysine and glycine in urine that can help monitoring the efficiency of treatments against the deleterious effects of type 1 diabetes.

     

Biochar as a Biocompatible Mild Anti-Inflammatory Supplement for Animal Feed and Agricultural Fields

Biochar is an organic material and high in carbon content, besides its use for energy purposes, it is also a material that serves the purpose of improving soil fertility, organic matter content of soils and removing heavy metals from water and soil. This study aims to investigate the antimicrobial effects of biochar whose beneficial effects on agricultural productivity has been proven by different studies. Scientific literature concerning the antibacterial, antifungal, and antiviral effects of the apricot seed and olive seed biochar is limited. Biochar applications may help to alter the microbial diversity by modifying biological environment either in agriculture or in animal husbandry. Moreover, biochar has been used in animal husbandry to improve animal health especially by regulating the intestinal flora and inflammation in the intestines. Hence, in our study, we investigated the effect of biochar on the growth of Aspergillus niger, Cryphonectria parasitica, Phytophthora cinnamomi, Plenodomus tracheiphilus, Enterococcus casseliflavus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and two different bacteriophage strains. Biochar did not have any direct effect on the growth of either Gram-positive or Gram-negative bacteria, bacteriophages, and fungi. In order to test their direct effects on the immune cells, mammalian macrophages were used and biochar directly reduced the inflammatory cytokine levels produced by the in vitro activated macrophages.     

Blood group O alleles in Native Americans: Implications in the peopling of the Americas

All major ABO blood alleles are found in most populations worldwide, whereas the majority of Native Americans are nearly exclusively in the O group. O allele molecular characterization could aid in elucidating the possible causes of group O predominance in Native American populations. In this work, we studied exon 6 and 7 sequence diversity in 180 O blood group individuals from four different Mesoamerican populations. Additionally, a comparative analysis of genetic diversity and population structure including South American populations was performed. Results revealed no significant differences among Mesoamerican and South American groups, but showed significant differences within population groups attributable to previously detected differences in genetic drift and founder effects throughout the American continent. Interestingly, in all American populations, the same set of haplotypes O¹, O^1v, and O^1v(G542A) was present, suggesting the following: (1) that they constitute the main genetic pool of the founding population of the Americas and (2) that they derive from the same ancestral source, partially supporting the single founding population hypothesis. In addition, the consistent and restricted presence of the G542A mutation in Native Americans compared to worldwide populations allows it to be employed as an Ancestry informative marker (AIM). Present knowledge of the peopling of the Americas allows the prediction of the way in which the G542A mutation could have emerged in Beringia, probably during the differentiation process of Asian lineages that gave rise to the founding population of the continent. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Up-regulation of the neuronal nicotinic receptor α7 by HIV glycoprotein 120: potential implications for HIV-associated neurocognitive disorder

Approximately 30-50% of the >30 million HIV-infected subjects develop neurological complications ranging from mild symptoms to dementia. HIV does not infect neurons, and the molecular mechanisms behind HIV-associated neurocognitive decline are not understood. There are several hypotheses to explain the development of dementia in HIV(+) individuals, including neuroinflammation mediated by infected microglia and neuronal toxicity by HIV proteins. A key protein associated with the neurological complications of HIV, gp120, forms part of the viral envelope and can be found in the CSF of infected individuals. HIV-1-gp120 interacts with several receptors including CD4, CCR5, CXCR4, and nicotinic acetylcholine receptors (nAChRs). However, the role of nAChRs in HIV-associated neurocognitive disorder has not been investigated. We studied the effects of gp120(IIIB) on the expression and function of the nicotinic receptor α7 (α7-nAChR). Our results show that gp120, through activation of the CXCR4 chemokine receptor, induces a functional up-regulation of α7-nAChRs. Because α7-nAChRs have a high permeability to Ca(2+), we performed TUNEL staining to investigate the effects of receptor up-regulation on cell viability. Our data revealed an increase in cell death, which was blocked by the selective antagonist α-bungarotoxin. The in vitro data are supported by RT-PCR and Western blot analysis, confirming a remarkable up-regulation of the α7-nAChR in gp120-transgenic mice brains. Specifically, α7-nAChR up-regulation is observed in mouse striatum, a region severely affected in HIV(+) patients. In summary, CXCR4 activation induces up-regulation of α7-nAChR, causing cell death, suggesting that α7-nAChR is a previously unrecognized contributor to the neurotoxicity associated with HIV infection.     

Epigenetically regulated clonal heritability of CTA expression profiles in human melanoma

The intratumoral heterogeneity of cancer testis antigens (CTA) expression, which is driven by promoter methylation status, may hamper the effectiveness of CTA‐directed vaccination of melanoma patients. Thus, we investigated whether the intratumoral heterogeneity of CTA expression is inherited at cellular level, or evolves throughout cellular replication, leading to a phenotypically unstable tumor cell population with reduced immunogenicity and/or able to escape immune control. Utilizing a previously characterized ex vivo clonal model of intratumoral heterogeneity of CTA expression in melanoma, Mel 313 MAGE‐A3‐low clone 5 (clone 5^M3‐low) and MAGE‐A3‐high clone 14 (clone 14^M3‐high) were sub‐cloned and analyzed for CTA profile. Molecular assays demonstrated that levels of MAGE‐A3 expression were highly conserved among generated sub‐clones, as compared to parental clones. A similar behavior was identified for an extensive panel of other CTA investigated. Inherited levels of MAGE‐A3 expression correlated with the extent of promoter methylation among clone 5^M3‐low and clone 14^M3‐high sub‐clones analyzed. Treatment of clone 5^M3‐low with a DNA hypomethylating agent (DHA) resulted in an up‐regulated expression of MAGE‐A3, which was inherited at single cell level, being still detectable at day 60 in its sub‐clones. Bisulfite sequencing demonstrated that also MAGE‐A3 promoter methylation status was inherited among sub‐clones generated from DHA‐treated clone 5^M3‐low and strictly correlated with MAGE‐A3 expression levels in investigated sub‐clones. Similar results were obtained for additional CTA studied. Altogether our findings demonstrate that constitutive and DHA‐modified CTA profiles of melanoma cells are clonally inherited throughout cellular replications, thus providing relevant insights to improve the effectiveness of CTA‐based immunotherapy. J. Cell. Physiol. 223: 352–358, 2010. © 2010 Wiley‐Liss, Inc.