Aggregation of human serum albumin during a thermal viral inactivation step

A terminal pasteurization step has been used for some plasma-derived protein products such as human serum albumin (HSA), which consists of heating the protein in solution at 60 °C for 10 h. Native and denaturing SDS-PAGE and dynamic light scattering were used to follow the stability of HSA during this process. It appears that a thermally unstable fraction, comprised primarily of haptoglobin, is involved in the formation of soluble aggregates of HSA. Therefore, it appears that aggregation during heat treatment is not due to conformational instability of HSA itself, but arises from unfolding of a thermally labile protein impurity. As haptoglobin aggregates, it entraps some HSA, which is present at much higher concentrations. This study emphasizes that, in a complex mixture of naturally occurring proteins, one thermally labile species can trigger aggregation of more stable proteins.     

Variants in the CNR1 and the FAAH Genes and Adiposity Traits in the Community

Pharmacologic blockade of the endocannabinoid receptor 1 leads to weight loss and an improved metabolic risk profile in overweight and obese individuals. We hypothesize that common genetic variants in the CNR1 (encoding endocannabinoid receptor 1) and FAAH genes (encoding fatty acid amide hydrolase, a key enzyme hydrolyzing endocannabinoids) are associated with adiposity traits. We genotyped 18 single‐nucleotide polymorphisms (SNPs) in the CNR1 gene and 9 SNPs in the FAAH gene in 2,415 Framingham Offspring Study participants (mean age 61 ± 10 years; 52.6% women; mean BMI 28.2 ± 5.4 kg/m²; 30.3% obese) and studied them for association with cross‐sectional and longitudinal measures of adiposity (BMI, waist circumference, change over time in BMI and waist circumference, visceral and subcutaneous adipose tissue) using linear mixed‐effect models. The selected SNPs captured 85% (r² = 0.8) of the common variation (minor allele frequency >5%) at the CNR1 locus and 96% (r² = 0.8) of the common variation at the FAAH locus (defined as the genomic segment containing the gene +20 kb upstream and +10 kb downstream). After correction for multiple testing, none of the SNPs in the CNR1 gene or in the FAAH gene displayed statistical evidence for association with BMI, waist circumference, and visceral adipose tissue or subcutaneous adipose tissue (all P > 0.18). Despite comprehensive SNP mapping across the genes and their regulatory regions in a large unselected sample, we failed to find evidence for an association of common variants in the CNR1 and FAAH genes with measures of adiposity in our community‐based sample.     

Adaptive radiation of the putrid perianth: Ferraria (Iridaceae: Irideae) and its unusual pollinators

Field studies of 13 of the estimated 17 species of the southern African geophytic genus Ferraria (Iridaceae: Iridoideae) identified four distinct pollination systems. Ferraria flowers are radially symmetric and cupped with a large, mostly pale or dull-colored perianth. Perigonal nectaries secrete hexose dominant (fructose and glucose) nectar. Most species are pollinated by Diptera of four families, apparently attracted by strong floral odors, mostly putrid or fermenting, but sometimes apparently sweet, and a large perianth mottled and edged with dark color. Concentrated sugary secretions are produced on the tepal claws that form a shallow floral cup. In contrast, flowers of F. ferrariola have a deep, narrow floral cup, a pale blue or yellow perianth, and a spicy scent and are pollinated by bees in the family Apidae, rewarded by nectar of moderate sugar concentration. Ferraria divaricata and F. variabilis have dull-colored, darkly speckled or streaked perianths and produce ample, highly dilute nectar pooled at the base of the floral cup and are pollinated by eumenid and masarine wasps (Vespidae). Lastly, F. uncinata has flowers with a narrow floral cup and dull violet tepals with brown margins. They are visited only by meloid and melyrid beetles. All pollen transfers from the anther of a Ferraria flower to an insect’s body are passive, regardless of pollinator. Pollen load analyses suggests that all pollinators show a high degree of faithfulness to Ferraria flowers.     

Visualization of Coronary Wall Atherosclerosis in Asymptomatic Subjects and Patients with Coronary Artery Disease Using Magnetic Resonance Imaging

Background

Magnetic resonance imaging (MRI) is sensitive to early atherosclerotic changes such as positive remodeling in patients with coronary artery disease (CAD). We assessed prevalence, quality, and extent of coronary atherosclerosis in a group of healthy subjects compared to patients with confirmed CAD.

Methodology

Twenty-two patients with confirmed CAD (15M, 7F, mean age 60.4±10.4 years) and 26 healthy subjects without history of CAD (11M, 15F, mean age 56.1±4.4 years) underwent MRI of the right coronary artery (RCA) and vessel wall (MR-CVW) on a clinical 1.5T MR-scanner. Wall thickness measurements of both groups were compared.

Principal Findings

Stenoses of the RCA (both < and ≥50% on CAG) were present in all patients. In 21/22 patients, stenoses detected at MRI corresponded to stenoses detected with conventional angiography. In 19/26 asymptomatic subjects, there was visible luminal narrowing in the MR luminography images. Fourteen of these subjects demonstrated corresponding increase in vessel wall thickness. In 4/26 asymptomatic subjects, vessel wall thickening without luminal narrowing was present. Maximum and mean wall thicknesses in patients were significantly higher (2.16 vs 1.92 mm, and 1.38 vs 1.22 mm, both p<0.05).

Conclusions

In this cohort of middle-aged individuals, both patients with stable angina and angiographically proven coronary artery disease, as well as age-matched asymptomatic subjects. exhibited coronary vessel wall thickening detectable with MR coronary vessel wall imaging. Maximum and mean wall thicknesses were significantly higher in patients. The vast majority of asymptomatic subjects had either positive remodeling without luminal narrowing, or non-significant stenosis.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00456950","term_id":"NCT00456950"}}NCT00456950     

Association of Group B Streptococcus Colonization and Bovine Exposure: A Prospective Cross-Sectional Cohort Study

Background

While Group B Streptococcus (GBS) human colonization and infection has long been suspected as originating from cows, several investigators have suggested that ongoing interspecies GBS transmission is unlikely due to genotyping data demonstrating that human and bovine-derived GBS strains represent mostly distinct populations. The possibility of ongoing transmission between humans and their livestock has not been systematically examined.

Methodology/Principal Findings

To examine ongoing interspecies transmission, we conducted a prospective cross-sectional cohort study of 68 families and their livestock. Stool specimens were collected from 154 people and 115 livestock; GBS was detected in 19 (12.3%) humans and 2 (1.7%) animals (bovine and sheep). Application of multilocus sequence typing (MLST) identified 8 sequence types (STs or clones), with STs 1 and 23 predominating. There were 11 families in which two members submitted stools and at least one had GBS colonization. In 3 of these families, both members (consisting of couples) were colonized, yielding a co-colonization rate of 27% (95% CI: 7%–61%). Two of these couples had strains with identical MLST, capsule (cps) genotype, susceptibility, and RAPD profiles. One couple co-colonized with ST-1 (cps5) strains also had a bovine colonized with the identical strain type. On multivariate analysis of questionnaire data, cattle exposure was a predictor of GBS colonization, with each unit increase in days of cattle exposure increasing the odds of colonization by 20% (P = 0.02). These results support interspecies transmission with additional evidence for transmission provided by the epidemiological association with cattle exposure.

Conclusions/Significance

Although GBS uncommonly colonizes livestock stools, increased frequency of cattle exposure was significantly associated with human colonization and one couple shared the same GBS strains as their bovine suggesting intraspecies transmission. These results set the framework for GBS as a possible zoonotic infection, which has significant public health implications.     

Chloroquine and Its Derivatives Exacerbate B19V-Associated Anemia by Promoting Viral Replication

Background

An unexpectedly high seroprevalence and pathogenic potential of human parvovirus B19 (B19V) have been observed in certain malaria-endemic countries in parallel with local use of chloroquine (CQ) as first-line treatment for malaria. The aims of this study were to assess the effect of CQ and other common antimalarial drugs on B19V infection in vitro and the possible epidemiological consequences for children from Papua New Guinea (PNG).

Methodology/Principal Findings

Viral RNA, DNA and proteins were analyzed in different cell types following infection with B19V in the presence of a range of antimalarial drugs. Relationships between B19V infection status, prior 4-aminoquinoline use and anemia were assessed in 200 PNG children <10 years of age participating in a case-control study of severe infections. In CQ-treated cells, the synthesis of viral RNA, DNA and proteins was significantly higher and occurred earlier than in control cells. CQ facilitates B19V infection by minimizing intracellular degradation of incoming particles. Only amodiaquine amongst other antimalarial drugs had a similar effect. B19V IgM seropositivity was more frequent in 111 children with severe anemia (hemoglobin <50 g/L) than in 89 healthy controls (15.3% vs 3.4%; P = 0.008). In children who were either B19V IgM or PCR positive, 4-aminoquinoline use was associated with a significantly lower admission hemoglobin concentration.

Conclusions/Significance

Our data strongly suggest that 4-aminoquinoline drugs and their metabolites exacerbate B19V-associated anemia by promoting B19V replication. Consideration should be given for choosing a non-4-aminoquinoline drug to partner artemisinin compounds in combination antimalarial therapy.     

Rheb fills a GAP between TSC and TOR

There has been much interest in determining the molecular and cellular functions of hamartin and tuberin, which are encoded by the genes TSC1 and TSC2 that are mutated in the tuberous sclerosis complex disease. Recently, several laboratories have independently reported a major breakthrough in this field. Together, these genetic, biochemical and cell-biological studies have demonstrated that the tuberin-hamartin complex inhibits target of rapamycin (TOR) signaling by acting as a GTPase-activating protein for the Ras-related small G protein Rheb.     

Vibrio cholerae bacteriophage CP-T1: characterization of bacteriophage DNA and restriction analysis

Temperature bacteriophage CP-T1 of Vibrio cholerae has a capsid that is 45 nm in diameter, a contractile tail 65 nm long and 9.5 nm wide, and a baseplate with several spikes or short tail fibers. The linear double-stranded DNA is 43.5 +/- 1.4 kilobases long, and the phage genome is both terminally redundant and partially circularly permuted. The extent of terminal redundancy is ca. 4%, and circular permutation is up to ca. 44%. Circular restriction maps have been constructed for the enzymes HindIII, EcoRI, BamHI, and PstI. By restriction endonuclease and heteroduplex analyses of phage DNA, the presence and location of a site (pac) at which packaging of phage DNA is initiated was established.     

RNA-polymerase binding sites within the tra region of the F factor of Escherichia coli K-12

Chimeric plasmids containing the tra operon of the Escherichia coli K-12 F factor were used to map by electron microscopy the RNA polymerase binding sites within the contiguous F EcoRI restriction fragments f6, f16, f1, f17, f19 and f2. [These fragments have been previously cloned in the EcoRI site of pSC101 to give the chimeric plasmids pRS27 (f6, f15), pRS29 (f15, f1) and pRS31 (f17, f19 and f2)]. The results may reflect the presence of a number of previously unrecognized promoters within the traY----Z operon.