Bacterial Colonization on Fecal Pellets of Harpacticoid Copepods and on Their Diatom Food

Fecal pellets make up a significant fraction of the global flux of organic matter in oceans, and the associated bacterial communities in particular are a potential food source for marine organisms. However, these communities remain largely unknown. In the present study, the bacterial communities on fecal pellets of the benthic copepod Paramphiascella fulvofasciata feeding on the diatoms Navicula phyllepta and Seminavis robusta were analyzed. The aim of this study was to characterize the bacterial communities associated with the diatoms and the fecal pellets by means of DGGE profiling. Furthermore, isolated bacteria were characterized by means of partial 16S rRNA gene sequencing. The composition of the bacterial microflora on fecal pellets was studied in terms of the effect of the original food source, the age of the fecal pellets and the copepod’s identity. Alphaproteobacteria, Flavobacteria, and Bacilli were found on the fecal pellets; whereas on diatoms, exclusively Gammaproteobacteria were identified. Especially after eating N. phyllepta, there was an important increase in bacterial diversity, although the diatom N. phyllepta harbored a less diverse bacterial community than S. robusta. Our data suggest that the additional bacteria originate from the copepod’s digestive tract and largely depends on the initial food source.     

Diversity and community structure of harpacticoid copepods associated with cold-water coral substrates in the Porcupine Seabight (North-East Atlantic)

The influence of microhabitat type on the diversity and community structure of the harpacticoid copepod fauna associated with a cold-water coral degradation zone was investigated in the Porcupine Seabight (North-East Atlantic). Three substrate types were distinguished: dead fragments of the cold-water coral Lophelia pertusa, skeletons of the glass sponge Aphrocallistes bocagei and the underlying sediment. At the family level, it appears that coral fragments and underlying sediment do not harbour distinctly different assemblages, with Ectinosomatidae, Ameiridae, Pseudotachidiidae, Argestidae and Miraciidae as most abundant. Conclusions on assemblage structure and diversity of the sponge skeletons are limited as only two samples were available. Similarity analysis at species level showed a strong variation in the sediment samples, which did not harbour a distinctly different assemblage in opposition to the coral and sponge samples. Several factors (sediment infill on the hard substrates, mobility of the copepods, limited sample sizes) are proposed to explain this apparent lack of a distinct difference between the microhabitats. Coral fragments and sediment were both characterised by high species diversity and low species dominance, which might indicate that copepod diversity is not substantially influenced by hydrodynamical stress. The additive partitioning of species diversity showed that by adding locations species richness was greatly enhanced. The harpacticoid community in the cold-water coral degradation zone is highly diverse and includes 157 species, 62 genera and 19 families. Information from neighbouring soft-bottom regions is necessary to assess whether total species diversity is increased by the presence of these complex habitat-providing substrates.     

Dietary Protein and Blood Pressure: A Systematic Review

Background

Elevated blood pressure (BP), which is a major risk factor for cardiovascular disease, is highly prevalent worldwide. Recently, interest has grown in the role of dietary protein in human BP. We performed a systematic review of all published scientific literature on dietary protein, including protein from various sources, in relation to human BP.

Methodology/Principal Findings

We performed a MEDLINE search and a manual search to identify English language studies on the association between protein and blood pressure, published before June 2010. A total of 46 papers met the inclusion criteria. Most observational studies showed no association or an inverse association between total dietary protein and BP or incident hypertension. Results of biomarker studies and randomized controlled trials indicated a beneficial effect of protein on BP. This beneficial effect may be mainly driven by plant protein, according to results in observational studies. Data on protein from specific sources (e.g. from fish, dairy, grain, soy, and nut) were scarce. There was some evidence that BP in people with elevated BP and/or older age could be more sensitive to dietary protein.

Conclusions/Significance

In conclusion, evidence suggests a small beneficial effect of protein on BP, especially for plant protein. A blood pressure lowering effect of protein may have important public health implications. However, this warrants further investigation in randomized controlled trials. Furthermore, more data are needed on protein from specific sources in relation to BP, and on the protein-BP relation in population subgroups.     

Intravaginal Practices,Vaginal Infections and HIV Acquisition: Systematic Review and Meta-Analysis

Background

Intravaginal practices are commonly used by women to manage their vaginal health and sexual life. These practices could, however, affect intravaginal mucosal integrity. The objectives of this study were to examine evidence for associations between: intravaginal practices and acquisition of HIV infection; intravaginal practices and vaginal infections; and vaginal infections and HIV acquisition.

Methodology/Principal Findings

We conducted a systematic review of prospective longitudinal studies, searching 15 electronic databases of journals and abstracts from two international conferences to 31^st January 2008. Relevant articles were selected and data extracted in duplicate. Results were examined visually in forest plots and combined using random effects meta-analysis where appropriate. Of 2120 unique references we included 22 publications from 15 different studies in sub-Saharan Africa and the USA. Seven publications from five studies examined a range of intravaginal practices and HIV infection. No specific vaginal practices showed a protective effect against HIV or vaginal infections. Insertion of products for sex was associated with HIV in unadjusted analyses; only one study gave an adjusted estimate, which showed no association (hazard ratio 1.09, 95% confidence interval, CI 0.71, 1.67). HIV incidence was higher in women reporting intravaginal cleansing but confidence intervals were wide and heterogeneity high (adjusted hazard ratio 1.88, 95%CI 0.53, 6.69, I² 83.2%). HIV incidence was higher in women with bacterial vaginosis (adjusted effect 1.57, 95%CI 1.26, 1.94, I² 19.0%) and Trichomonas vaginalis (adjusted effect 1.64, 95%CI 1.28, 2.09, I² 0.0%).

Conclusions/Significance

A pathway linking intravaginal cleaning practices with vaginal infections that increase susceptibility to HIV infection is plausible but conclusive evidence is lacking. Intravaginal practices do not appear to protect women from vaginal infections or HIV and some might be harmful.     

Filamentous fungi as production organisms for glycoproteins of bio-medical interest

Filamentous fungi are commonly used in the fermentation industry for large scale production of glycoproteins. Several of these proteins can be produced in concentrations up to 20–40 g per litre. The production of heterologous glycoproteins is at least one or two orders of magnitude lower but research is in progress to increase the production levels. In the past years the structure of protein-linked carbohydrates of a number of fungal proteins has been elucidated, showing the presence of oligo-mannosidic and high-mannose chains, sometimes with typical fungal modifications. A start has been made to engineer the glycosylation pathway in filamentous fungi to obtain strains that show a more mammalian-like type of glycosylation. This mini review aims to cover the current knowledge of glycosylation in filamentous fungi, and to show the possibilities to produce glycoproteins with these organisms with a more mammalian-like type of glycosylation for research purposes or pharmaceutical applications     

Development and validation of a method to determine the unbound paclitaxel fraction in human plasma

Paclitaxel is pharmaceutically formulated in a mixture of Cremophor EL and ethanol (1:1, v/v). The unbound fraction of the anticancer drug paclitaxel in plasma is dependent on both plasma protein binding and entrapment in Cremophor EL micelles. We have developed a simple and reproducible method for the quantification of the unbound paclitaxel fraction in human plasma. Human plasma was spiked with [3H]paclitaxel and [14C]glucose (unbound reference) and incubated at 37 degrees C for 30 min. Plasma ultrafiltrate was prepared by a micropartition system (MPS-1) and collected in a sample cup containing 100 microl of plasma to prevent the loss of paclitaxel due to adsorption. The radionuclides were separated after combustion of the biological samples using a sample oxidizer and the radioactivity was determined by liquid scintillation counting. The unbound fraction of paclitaxel was calculated by dividing the ratios of 3H and 14C in plasma ultrafiltrate and in plasma. The method was thoroughly validated using human plasma spiked with pharmacologically relevant concentrations of paclitaxel (10-1000 ng/ml) and Cremophor EL (0.25-2.0%). The method was precise, with a within-day precision ranging from 3.9 to 11.0% and a between-day precision ranging from 5.8 to 13.1%. In patient plasma with low serum albumin values containing 1% of Cremophor EL, the unbound fraction appeared to be significantly higher than that in plasma with normal albumin values. The determination of the unbound fraction of paclitaxel proved to be stable during a 10-week storage at -20 degrees C. Furthermore, the assay was applicable in patient samples. This assay can be used to determine the unbound fraction of paclitaxel in plasma. Moreover, its design should allow the determination of the unbound concentrations of other hydrophobic drugs.     

Diversity of the human immunodeficiency virus type 1 (HIV-1) env sequence after vertical transmission in mother-child pairs infected with HIV-1 subtype A

Although several virologic and immunologic factors associated with an increased risk of perinatal human immunodeficiency virus type 1 (HIV-1) transmission have been described, the mechanism of mother-to-child transmission is still unclear. More specifically, the question of whether selective pressures influence the transmission remains unanswered. The aim of this study was to assess the genetic diversity of the transmitted virus after in utero transmission and after peripartum transmission and to compare the viral heterogeneity in the child with the viral heterogeneity in the mother. To allow a very accurate characterization of the viral heterogeneity in a single sample, limiting-dilution sequencing of a 1016-bp fragment of the env gene was performed. Thirteen children were tested, including 6 with in utero infections and 7 with peripartum infections. Samples were taken the day after birth and at the ages of 6 and 14 weeks. A homogeneous virus population was seen in six (46.2%) infants, of whom two were infected in utero and four were infected peripartum. A more heterogeneous virus population was detected in seven infants (53.8%), four infected in utero and three infected peripartum. The phylogenetic trees of the mother-child pairs presented a whole range of different tree topologies and showed infection of the child by one or more maternal variants. In conclusion, after HIV-1 transmission from mother to child a heterogeneous virus population was detected in approximately one-half of the children examined. Heterogeneous virus populations were found after peripartum infection as well as after in utero infection. Phylogenetic tree topologies argue against selection processes as the major mechanism driving mother-to-child transmission but support the hypothesis that virus variability is mainly driven by the inoculum level and/or exposure time.