Atmospheric culturable bacteria associated with meteorological conditions at a summer-time site in the mid-Willamette Valley,Oregon

A set of simultaneously collected quantitative measurements of 12 meteorological and 6 culturable atmospheric bacterial (CAB) variables was made over a grass seed field during several early, mid, and late summer days. The observation site was located between the Cascade and Coastal Mountain Ranges near Corvallis in the Willamette Valley, Oregon. Principal component analysis identified those meteorological variables that had the highest loadings in six eigenvectors that account for 95.9% of variation in the data factors, i.e., temperature @ 6.3 m above ground level (AGL), wind velocity @ 10.0 m AGL, wind velocity difference @ 1.7–10.0 m, barometric pressure, wind direction standard deviation, and wind direction. When these variables were used in a cluster analysis, they formed three statistically distinct meteorological variable clusters with means at ca. “midnight”, ca. “midday”, and ca. “evening.” The highest mean density of CAB (i.e., 153.4 ± 162.5 CFU/m³) was associated with the “midday” meteorological Cluster-1 that had warm, dry “gentle breezes” from the southeast, in the relatively bacteria loaded Willamette Valley air. The lowest mean density of CAB (i.e., 35.5 ± 24.1 CFU/m³) was associated with meteorological Cluster-3 in the late afternoon and “evening” occurring during the hottest and driest part of the day with “fresh breezes” coming from the north northwest in air off the Pacific Ocean. Finally, the last cluster, Cluster-2 occurred about midnight and had an intermediate density of CAB (74.2 ± 76.2 CFU/m³) in “light air” coming from the northwest, perhaps off the Pacific Ocean. The CAB associated with each of the three meteorological clusters was only partially statistically distinct. Partially because the CAB in both the Pacific Ocean derived air masses of the “evening” Cluster-3 and “midnight” Cluster-2 were not statically separable, though both were statistically separable from the midday, Willamette Valley derived Cluster-1. Further indicating their common source, both Pacific Ocean derived air masses had very similar percentages of pigmented bacteria, which were dissimilar to the pigmented bacterial population density in the Willamette Valley air masses. In short, it is speculated that “midnight” atmosphere may simply contain the settling concentrated residual bacterial particles in the abated fresh Pacific Ocean breezes after sundown. It is clearly shown that with the methods employed, it is possible to associate the uniqueness of the quantity, and to a lesser extent the quality, of the CAB population with the atmospheric conditions reported herein. From this project comes speculation that the strategies relating the quasi-conservative bacterial populations associated with distinct but nonconservative air mass properties can help to better understand more of the bacterial dynamics found in such situations. And to a further extent, molecular biological methods could be applied to identify bacterial taxa in specific air masses.     

Complete genome sequence of Desulfotomaculum acetoxidans type strain (5575)

Desulfotomaculum acetoxidans Widdel and Pfennig 1977 was one of the first sulfate-reducing bacteria known to grow with acetate as sole energy and carbon source. It is able to oxidize substrates completely to carbon dioxide with sulfate as the electron acceptor, which is reduced to hydrogen sulfide. All available data about this species are based on strain 5575(T), isolated from piggery waste in Germany. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a Desulfotomaculum species with validly published name. The 4,545,624 bp long single replicon genome with its 4370 protein-coding and 100 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Common genetic variation in multiple metabolic pathways influences susceptibility to low HDL-cholesterol and coronary heart disease

A low level of HDL-C is the most common plasma lipid abnormality observed in men with established coronary heart disease (CHD). To identify allelic variants associated with susceptibility to low HDL-C and CHD, we examined 60 candidate genes with key roles in HDL metabolism, insulin resistance, and inflammation using samples from the Veterans Affairs HDL Intervention Trial (VA-HIT; cases, n = 699) and the Framingham Offspring Study (FOS; controls, n = 705). VA-HIT was designed to examine the benefits of HDL-raising with gemfibrozil in men with low HDL-C (≤40 mg/dl) and established CHD. After adjustment for multiple testing within each gene, single-nucleotide polymorphisms (SNP) significantly associated with case status were identified in the genes encoding LIPC (rs4775065, P < 0.0001); CETP (rs5882, P = 0.0002); RXRA (rs11185660, P = 0.0021); ABCA1 (rs2249891, P = 0.0126); ABCC6 (rs150468, P = 0.0206; rs212077, P = 0.0443); CUBN (rs7893395, P = 0.0246); APOA2 (rs3813627, P = 0.0324); SELP (rs732314, P = 0.0376); and APOC4 (rs10413089, P = 0.0425). Included among the novel findings of this study are the identification of susceptibility alleles for low HDL-C/CHD risk in the genes encoding CUBN and RXRA, and the observation that genetic variation in SELP may influence CHD risk through its effects on HDL.     

Dynamics of the cyanobacterial photosynthetic network: communication and modification of membrane protein complexes

Cyanobacterial photosystem 2 and cytochrome b(6)f complexes have been structurally resolved up to the molecular level while the adjustment of their function in response to environmental and intracellular parameters is based on various modifications of these complexes which have not yet been resolved in detail. This minireview summarizes recent results on two central modifications for each complex: (a) for the cytochrome b(6)f complex the implication of PetP, a new subunit, and of three copies of PetC, the Rieske protein, for the fine-tuning of the photosynthetic electron transport is evaluated; (b) for photosystem 2, the heterogeneity of the D1 subunit and the role of subunit Psb27 is discussed in relation to stress response and the biogenesis/repair cycle. The presented "dynamic" models for both complexes should illustrate the need to complement structural by more extensive functional models which consider the flexibility of individual complexes in the physiological context - beyond structure.     

Collaborative study for the calibration of a replacement international standard for diphtheria toxoid adsorbed

We present the results of a collaborative study for the characterization of a preparation of diphtheria toxoid adsorbed, and its calibration in terms of the 3rd International Standard (IS) for Diphtheria Toxoid Adsorbed. Calibration was performed using established World Health Organization (WHO) and European Pharmacopoeia (Ph. Eur.) protection models. Two candidate toxoid preparations were included in the study, one of which was adopted as a replacement Ph. Eur. Biological Reference Preparation (BRP, batch 4) in February 2009. The second candidate preparation was found to have a unitage of 213 IU/ampoule based on the calibration by in vivo bioassay in 19 laboratories in 16 countries, and was established as the 4th IS for Diphtheria Toxoid Adsorbed by the WHO Expert Committee on Biological Standardization (ECBS) in October 2009.The study also assessed performance of the replacement standard in mouse and guinea pig serological assays which are used as alternative procedures for diphtheria potency testing. Participants tested both candidate preparations and potency was expressed in relative terms only. Results suggest that the replacement standard is suitable for use as the reference vaccine in serological assays and that the Vero cell assay may be suitable for calibration of future replacement standards.     

Terpene synthases and the regulation, diversity and biological roles of terpene metabolism

Terpene synthases are the primary enzymes in the formation of low-molecular-weight terpene metabolites. Rapid progress in the biochemical and molecular analysis of terpene synthases has allowed significant investigations of their evolution, structural and mechanistic properties, and regulation. The organization of terpene synthases in large gene families, their characteristic ability to form multiple products, and their spatial and temporal regulation during development and in response to biotic and abiotic factors contribute to the time-variable formation of a diverse group of terpene metabolites. The structural diversity and complexity of terpenes generates an enormous potential for mediating plant-environment interactions. Engineering the activities of terpene synthases provides opportunities for detailed functional evaluations of terpene metabolites in planta.     

Enzyme histochemistry and hormones of the developing gastrointestinal tract of the chick embryo

Summary The oxidative enzymes are important in most metabolic processes. Their localisations in embryonic tissues may indicate the onset of important metabolic processes essential for both histodifferentiation and chemodifferentiation. The diphosphate nucleotide and the triphosphate nucleotide diaphorases have been demonstrated as early as the 8th day.Isocitric dehydrogenase, glucose-6-phosphate dehydrogenase and lactic dehydrogenase have been demonstrated histochemically in the epithelial cells and in muscle cells of both stomach-complex and intestine as early as the 6th day. The intensity of these histochemical reactions appears to increase with the age of the embryo reaching a maximum before hatching and indicating the onset of secretory and absorptive functions.     

A Leishmania donovani gene that confers accelerated recovery from stationary phase growth arrest

We have isolated a gene, LdGF1, from the protozoan parasite Leishmania donovani. Overexpression of this gene confers a strong selective advantage in liquid culture after stationary phase growth arrest. We could show that recombinant L. donovani or Leishmania major, when overexpressing LdGF1, recover faster from a stationary phase growth arrest than control parasite strains. While no advantage of LdGF1 overexpression could be observed in log phase cultures or after a hydroxyurea-induced S-phase growth arrest, recovery from a cell cycle arrest due to serum deprivation was faster in LdGF1-overexpressing strains. This was found to be due to an accelerated release from a G₁ cell cycle arrest. By contrast, in a BALB/c mouse infection system, overexpression of LdGF1 in L. major resulted in reduced virulence. We conclude that increased levels of LdGF1 are beneficiary during recovery from G₁ cell cycle arrest, but pose a disadvantage inside a mammalian host. These results are discussed in the context of the observed loss of virulence during in vitro passage of Leishmania parasites.     

Functional characterization of pendrin in a polarized cell system. Evidence for pendrin-mediated apical iodide efflux

Pendred's syndrome is an autosomal recessive disorder characterized by sensorineural deafness, goiter, and impaired iodide organification. It is caused by mutations in the PDS/SLC26A4 gene that encodes pendrin. Functionally, pendrin is a transporter of chloride and iodide in Xenopus oocytes and heterologous mammalian cells and a chloride/base exchanger in beta-intercalated cells of the renal cortical collecting duct. The partially impaired thyroidal iodide organification in Pendred's syndrome suggests a possible role of pendrin in iodide transport at the apical membrane of thyroid follicular cells, but experimental evidence for this concept is lacking. The iodide transport properties of pendrin were determined in polarized Madin-Darby canine kidney cells expressing the sodium iodide symporter (NIS), pendrin, or NIS and pendrin using a bicameral system-permitting measurement of iodide content in the basal, intracellular, and apical compartments. Moreover, we determined the functional consequences of two naturally occurring mutations (L676Q and FS306>309X). In polarized Madin-Darby canine kidney cells, NIS mediates uptake at the basolateral membrane. Only minimal amounts of iodide reach the apical compartment in the absence of pendrin. In cells expressing NIS and pendrin, pendrin mediates transport of iodide into the apical chamber. Wild type pendrin also mediates iodide efflux in transiently transfected cells. In contrast, both pendrin mutants lose the ability to promote iodide efflux. These results provide evidence that pendrin mediates apical iodide efflux from polarized mammalian cells loaded with iodide. Consistent with the partial organification defect observed in patients with Pendred's syndrome, naturally occurring mutations of pendrin lead to impaired transport of iodide.