Abundance of archaeal and bacterial ammonia oxidizers – Possible bioindicator for soil monitoring

Many soil functions are driven by soil microorganisms and they have therefore been identified as appropriate indicators for monitoring of soil status. Genetic profiling of the bacterial ammonia oxidizing community was recently top-scored as soil biological indicator (Ritz et al., 2009). However, ammonia oxidation is not only performed by bacteria, but also ammonia oxidizing archaea. Based on the suggested niche differentiation between these two groups and findings that they are susceptible to environmental change in soil ecosystems at varying scales, we suggest that the abundance of these two communities rather than community profiling of the ammonia oxidizing bacteria could serve as a relevant and cost-effective bioindicator for soil monitoring.     

Do Stress Responses Promote Leukemia Progression? An Animal Study Suggesting a Role for Epinephrine and Prostaglandin-E2 through Reduced NK Activity

In leukemia patients, stress and anxiety were suggested to predict poorer prognosis. Oncological patients experience ample physiological and psychological stress, potentially leading to increased secretion of stress factors, including epinephrine, corticosteroids, and prostaglandins. Here we tested whether environmental stress and these stress factors impact survival of leukemia-challenged rats, and studied mediating mechanisms. F344 rats were administered with a miniscule dose of 60 CRNK-16 leukemia cells, and were subjected to intermittent forced swim stress or to administration of physiologically relevant doses of epinephrine, prostaglandin-E(2) or corticosterone. Stress and each stress factor, and/or their combinations, doubled mortality rates when acutely applied simultaneously with, or two or six days after tumor challenge. Acute administration of the β-adrenergic blocker nadolol diminished the effects of environmental stress, without affecting baseline survival rates. Prolonged β-adrenergic blockade or COX inhibition (using etodolac) also increased baseline survival rates, possibly by blocking tumor-related or normal levels of catecholamines and prostaglandins. Searching for mediating mechanisms, we found that each of the stress factors transiently suppressed NK activity against CRNK-16 and YAC-1 lines on a per NK basis. In contrast, the direct effects of stress factors on CRNK-16 proliferation, vitality, and VEGF secretion could not explain or even contradicted the in vivo survival findings. Overall, it seems that environmental stress, epinephrine, and prostaglandins promote leukemia progression in rats, potentially through suppressing cell mediated immunity. Thus, patients with hematological malignancies, which often exhibit diminished NK activity, may benefit from extended β-blockade and COX inhibition.     

Solvent isotope effects in intramolecular catalysis: Acyl transfer reactions of 4-nitrophenyl 5-nitrosalicylate in aqueous tris buffer

A kinetic study of the reactions of 4-nitrophenyl 5-nitrosalicylate in aqueous Tris buffer at 25°C has revealed three kinetically significant reactions: Tris aminolysis of the un-ionized substrate, Tris aminolysis of the ionized substrate, and spontaneous hydrolysis of the ionized substrate. Solvent isotope effects have been measured for all three reactions. Mechanisms are discussed, and the conclusion is reached that intramolecular catalysis is operating in only the spontaneous hydrolysis.     

Apelin cells in the rat stomach

Apelin is a recently discovered peptide that is the endogenous ligand for the APJ receptor. Apelin is produced in the central nervous system, heart, lung, mammary gland and gastrointestinal (GI) tract. The aim of this study was to identify by immunohistochemistry (IHC) cell types in the rat stomach that produce apelin peptide. IHC revealed abundant apelin-positive cells, primarily in the neck and upper base regions of the gastric glands in the mucosal epithelium. Apelin is not detected in the muscle layer. Apelin-positive cells were identified as mucous neck, parietal cells, and chief cells. Apelin is also identified in gastric epithelial cells that produce chromogranin A (CGA), a marker of enteroendocrine cells. The findings that apelin is expressed in gastric exocrine and endocrine cells agrees with and extends other data showing that apelin peptide is measurable in the gut lumen and in the systemic circulation by immunoassay.     

Leukomogenic factors downregulate heparanase expression in acute myeloid leukemia cells

Heparanase is a heparan sulfate-degrading endoglycosidase expressed by mature monocytes and myeloid cells, but not by immature hematopoietic progenitors. Heparanase gene expression is upregulated during differentiation of immature myeloid cells. PML-RARalpha and PLZF-RARalpha fusion gene products associated with acute promyelocytic leukemia abrogate myeloid differentiation and heparanase expression. AML-Eto, a translocation product associated with AML FAB M2, also downregulates heparanase gene expression. The common mechanism that underlines the activity of these three fusion gene products involves the recruitment of histone deacetylase complexes to specific locations within the DNA. We found that retinoic acid that dissociates PML-RARalpha from the DNA, and which is used to treat acute promyelocytic leukemia patients, restores heparanase expression to normal levels in an acute promyelocytic leukemia cell line. The retinoic acid effects were also observed in primary acute promyelocytic leukemia cells and in a retinoic acid-treated acute promyelocytic leukemia patient. Histone deacetylase inhibitor reverses the downregulation of heparanase expression induced by the AML-Eto fusion gene product in M2 type AML. In summary, we have characterized a link between leukomogenic factors and the downregulation of heparanase in myeloid leukemic cells.     

Are the low protein requirements of nectarivorous birds the consequence of their sugary and watery diet? A test with an omnivore

Nectar-feeding birds have remarkably low nitrogen requirements. These may be due either to adaptation to a low-protein diet or simply to feeding on a fluid diet that minimizes metabolic fecal nitrogen losses. We measured minimal nitrogen requirements (MNR) and total endogenous nitrogen loss (TENL) in the omnivorous European starling Sturnus vulgaris, fed on an artificial nectar-like fluid diet of varying concentrations of sugar and protein. The MNR and TENL of the birds were similar and even slightly higher than allometrically expected values for birds of the starlings' mass (140% and 103%, respectively). This suggests that the low measured nitrogen requirements of nectar-feeding birds are not simply the result of their sugary and watery diets but a physiological adaptation to the low nitrogen input. We also measured the effect of water and protein intake on the nitrogenous waste form in the excreta and ureteral urine in European starlings. Neither high water intake nor low protein intake increased the fraction of nitrogen excreted as ammonia. Ammonia was excreted at consistently low levels by the starlings, and its concentration was significantly higher in ureteral urine than in excreta. We hypothesize that ureteral ammonia was reabsorbed in the lower intestine, indicating a postrenal modification of the urine.     

Quantitative high-throughput measurement of gene expression with sub-zeptomole sensitivity by capillary electrophoresis

Microarray technologies have provided the ability to monitor the expression of whole genomes rapidly. However, concerns persist with regard to quantitation and reproducibility, and the detection limits for individual genes in particular arrays are generally unknown. This article describes a semiautomated PCR-based technology, Q-RAGE, which rapidly provides measurements of mRNA abundance with extremely high sensitivity using fluorescent detection of specific products separated by capillary electrophoresis. A linear relationship between template concentration and fluorescent signal can be demonstrated down to template concentrations in the low aM region, corresponding to approximately 0.04 zmol (24 molecules) per reaction. The technique is shown to be quantitative over five orders of magnitude of template concentration, and average mRNA abundances of approximately 0.01 molecule per cell can be detected. A single predefined set of 320 primers provides 90-95% coverage of all eukaryotic genomes. Analysis of a set of 19 p53-regulated genes in untreated cultures of normal human epithelial cells, derived from three different tissues, revealed a 600-fold range of apparent constitutive expression levels. For most of the genes assayed, good correlations were observed among the expression levels in normal mammary, bronchial, and epidermal epithelial cells.     

Phylogenetic analysis of nuclear and mitochondrial DNA reveals a complex of cryptic species in Crassicutis cichlasomae (Digenea: Apocreadiidae), a parasite of Middle-American cichlids

We obtained nuclear ITS-1 and mitochondrial cox1 sequences from 225 Crassicutis cichlasomae adults collected in 12 species of cichlids from 32 localities to prospect for the presence of cryptic species. This trematode is commonly found in species of cichlids over a wide geographic range in Middle-America. Population-level phylogenetic analyses of ITS-1 and cox1, assessments of genetic and haplotype diversity, and morphological observations revealed that C. cichlasomae represents a complex of seven cryptic species for which no morphological diagnostic characters have been discovered thus far. Bayesian and Maximum Likelihood analyses of concatenated datasets (906 bp) recovered eight lineages of C. cichlasomae, all with high posterior probabilities and bootstrap branch support. Values of genetic divergence between clades ranged from 1.0% to 5.2% for ITS-1, and from 7.2% to 30.0% for cox1. Morphological study of more than 300 individuals did not reveal structural diagnostic traits for the species defined using molecular evidence. These observations indicate that some traditional morphological characters (e.g., testes position) have substantial intra-specific variation, and should be used with caution when classifying C. cichlasomae and their sister taxa. Additionally, phylogenetic analyses did not reveal a strict correlation between these cryptic species and their host species or geographic distribution, however it appears that genetic distinctiveness of these cryptic species was influenced by the diversification and biogeographical history of Middle-American cichlids.     

Long-chain polyunsaturated fatty acids in maternal and infant nutrition

Homo sapiens has evolved on a diet rich in alpha-linolenic acid and long chain polyunsaturated fatty acids (LCP). We have, however, gradually changed our diet from about 10,000 years ago and accelerated this change from about 100 to 200 years ago. The many dietary changes, including lower intake of omega3-fatty acids, are related to 'typically Western' diseases. After a brief introduction in essential fatty acids (EFA), LCP and their functions, this contribution discusses our present low status of notably LCPomega3 in the context of our rapidly changing diet within an evolutionary short time frame. It then focuses on the consequences in pregnancy, lactation and neonatal nutrition, as illustrated by some recent data from our group. We discuss the concept of a 'relative' EFA/LCP deficiency in the fetus as the outcome of high transplacental glucose flux. This flux may in the fetus augment de novo synthesis of fatty acids, which not only dilutes transplacentally transported EFA/LCP, but also causes competition of de novo synthesized oleic acid with linoleic acid for delta-6 desaturation. Such conditions were encountered by us in mothers with high body mass indices, diabetes mellitus and preeclampsia. The unifying factor might be compromised glucose homeostasis. In search of the milk arachidonic acid (AA) and docosahexaenoic acid (DHA) contents of our African ancestors, we investigated women in Tanzania with high intakes of freshwater fish as only animal lipid source. These women had milk AA and DHA contents that were well above present recommendations for infant formulae. Both studies stimulate rethinking of 'optimal homeostasis'. Subtle signs of dysbalanced maternal glucose homeostasis may be important and observations from current Western societies may not provide us with an adequate basis for dietary recommendations.