Snapshot prediction of carbon productivity,carbon and protein content in a Southern Ocean diatom using FTIR spectroscopy

Diatoms, an important group of phytoplankton, bloom annually in the Southern Ocean, covering thousands of square kilometers and dominating the region''s phytoplankton communities. In their role as the major food source to marine grazers, diatoms supply carbon, nutrients and energy to the Southern Ocean food web. Prevailing environmental conditions influence diatom phenotypic traits (for example, photophysiology, macromolecular composition and morphology), which in turn affect the transfer of energy, carbon and nutrients to grazers and higher trophic levels, as well as oceanic biogeochemical cycles. The paucity of phenotypic data on Southern Ocean phytoplankton limits our understanding of the ecosystem and how it may respond to future environmental change. Here we used a novel approach to create a ‘snapshot'' of cell phenotype. Using mass spectrometry, we measured nitrogen (a proxy for protein), total carbon and carbon-13 enrichment (carbon productivity), then used this data to build spectroscopy-based predictive models. The models were used to provide phenotypic data for samples from a third sample set. Importantly, this approach enabled the first ever rate determination of carbon productivity from a single time point, circumventing the need for time-series measurements. This study showed that Chaetoceros simplex was less productive and had lower protein and carbon content during short-term periods of high salinity. Applying this new phenomics approach to natural phytoplankton samples could provide valuable insight into understanding phytoplankton productivity and function in the marine system.     

Reducing HIV Risk among Transgender Women in Thailand: A Quasi-Experimental Evaluation of the Sisters Program

Transgender women are particularly at risk of HIV infection, but little evidence exists on effective HIV prevention strategies with this population. We evaluated whether Sisters, a peer-led program for transgender women, could reduce HIV risks in Pattaya, Thailand. The study used time-location sampling to recruit 308 transgender women in Pattaya into a behavioral survey in 2011. Coarsened exact matching was used to create statistically equivalent groups of program participants and non-participants, based on factors influencing likelihood of program participation. Using multivariable logistic regression, we estimated effects of any program participation and participation by delivery channel on: condom use at last sex; consistent condom and condom/water-based lubricant use in the past 3 months with commercial, casual, and regular partners; and receipt of HIV testing in the past 6 months. Program coverage reached 75% of the population. In a matched sub-sample (n = 238), participation in outreach was associated with consistent condom/water-based lubricant use with commercial partners (AOR 3.22, 95% CI 1.64–6.31). Attendance at the Sisters drop-in center was associated with receiving an HIV test (AOR 2.58, 95% CI 1.47–4.52). Dedicated transgender-friendly programs are effective at reducing HIV risks and require expansion to better serve this key population and improve HIV prevention strategies.     

Analysis of γ-Aminobutyric AcidA Receptor Subunits in the Mouse Cochlea by Means of the Polymerase Chain Reaction

Abstract: Unlike 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces consistent decreases in levels of striatal dopamine (DA) with considerably smaller and more variable effects on mouse brain levels of serotonin (5-HT) and norepinephrine (NE), a novel amine-substituted MPTP analogue, 1-methyl-4-(2'-aminophenyl)-1,2,3,6-tetrahydropyridine (2'-NH₂-MPTP), administered in a standard mouse dosing paradigm for MPTP (20 mg/kg X 4) did not affect striatal DA but led to marked reductions (60–70%) in levels of 5-HT, 5-hydroxyindoleacetic acid (5-HIAA), and NE measured in frontal cortex and hippocampus 1 week after treatment. Another 2'-substituted MPTP analogue, 1-methyl-4-(2'-methylphenyl)-1,2,3,6-tetrahydropyridine, affected cortical and hippocampal 5-HT, 5-HIAA, and NE only minimally, while markedly reducing the DA content in striatum (90%), thus indicating that the substituent (-NH₂ versus -CH₃) at the 2'position is important for the differential effects of these MPTP analogues. In a replication study with a 3-week end point, hippocampal and cortical 5-HT, 5-HIAA, and NE levels remained depressed with no indication of recovery. These results suggest that 2'-NH₂-MPTP may be a novel, regionally selective neurotoxin for serotonergic and norad-renergic nerve terminals.     

The dominant phosphoprotein pp65 (UL83) of human cytomegalovirus is dispensable for growth in cell culture.

The phosphoprotein pp65 (ppUL83) of human cytomegalovirus (HCMV) is abundantly synthesized during lytic infection in cultured fibroblasts. As a major constituent of extracellular particles, it gains entry to infected cells immediately after adsorption and subsequently translocates to the cell nucleus. This efficient transport is mediated by unique nuclear localization signals. To study the function of pp65, a viral deletion mutant was constructed by replacing the pp65 gene with the bacterial neomycin phosphotransferase gene, driven by the simian virus 40 early promoter. The resulting virus, RVAd65, could be grown and selected on human fibroblasts without complementation. The deletion of the pp65 gene in RVAd65 was verified by using Southern blot and PCR analyses. The lack of expression from the gene was investigated by immunoblotting with pp65-specific monoclonal antibodies. Single-cycle growth analyses showed that RVAd65 grew to levels of infectivity comparable to those of the wild-type virus. Therefore, pp65 is nonessential for the growth of HCMV in human fibroblasts. Electron microscopy revealed no differences in the processes of virion morphogenesis, although the maturation appeared to be delayed. However, the kinetics of expression of the immediate-early genes UL122 and UL123, the early gene UL44, and the late gene UL32 were the same in RVAd65-infected cells as in wild-type virus-infected cells in immunoblot analyses. In vitro phosphorylation assays showed that some of the virion proteins were labelled to a markedly reduced extent by virion-associated kinases in RVAd65 compared with wild-type virus. We therefore conclude that although deletion of the pp65 gene does not abolish replication of HCMV, a recombinant virus lacking pp65 displays phenotypic alterations compared with wild-type virus during growth in cultured fibroblasts.     

Scanning and transmission electron microscopic study of the supraependymal macrophages in the lateral ventricles of the toad brain

Transmission and scanning electron microscopy of the lateral ventricles of the toad brain revealed the presence of supraependymal cells that have the features of macrophages. Based solely on their surface morphology three different cell forms could be identified. The most frequently observed cells are flat and multipolar, and have a smooth or ruffled surface. The second type is spherical with a ruffled surface and occurs either singly, in which case it lacks processes, or in clusters from which processes radiate. The third type has surface blebs and numerous thin, smooth processes. However, when specimens that had been examined in the scanning electron microscope are viewed in the transmission electron microscope, all cells appear to belong to a single cell type. All cells viewed closely resemble macrophages in that they contain nuclei with clumped chromaffin, single cisternae of rough endoplasmic reticulum, numerous dense bodies, and many Golgi complexes. In addition, when horseradish peroxidase (HRP) was perfused into the ventricles, reaction product was found a short time thereafter within cytoplasmic vacuoles, and after a longer period within dense bodies. Because of their ultrastructural resemblance to macrophages and their capacity to ingest HRP, we suggest that these cells function as phagocytes and, as such, act to remove foreign materials from the cerbrospinal fluid.     

N-Acetylhistidine, Glutamate, and β-Alanine Are Concentrated in a Receptor Cell Layer of the Trout Inner Ear

An epithelial sheet isolated from the trout saccular macula, highly enriched in acousticolateralis receptor cells (hair cells), has been analyzed for primary amine-containing compounds. The hair cell preparation, compared to the saccular nerve, was found to contain elevated levels of the presumptive receptoneural transmitter, glutamate, as well as beta-alanine, and components eluting in the positions of the standards phosphoserine and phosphoethanolamine on cation-exchange HPLC. Saccular nerve contained a different spectrum of primary amines and was elevated specifically in carnosine/homocarnosine. Acid hydrolysis of perchlorate extracts of both hair cell and nerve fractions yielded large amounts of histidine. For the saccular nerve fraction, production of histidine by acid hydrolysis was matched by production of beta-alanine and gamma-aminobutyric acid (GABA) and disappearance of carnosine/homocarnosine. The dipeptides carnosine and homocarnosine have been chromatographically resolved by expanded HPLC and found to be present in saccular nerve in a ratio of approximately 10:1, respectively. Production of histidine in the hair cell extract was not coupled with production of beta-alanine and GABA. The hair cell histidine-containing unknown, present in millimolar concentration, has been identified as N-acetylhistidine by the hydrolysis and rechromatography of fractions from cation-exchange HPLC. The large and specific presence of N-acetylhistidine in the hair cell preparation, together with electrophysiological evidence for its facilitatory action on afferent fibers in the frog semicircular canal, is suggestive of a role for this molecule as well as glutamate in acousticolateralis receptoneural transmission.     

Molecular variants of human papillomavirus type 16 from four continents suggest ancient pandemic spread of the virus and its coevolution with humankind.

We have amplified by the polymerase chain reaction, cloned, and sequenced genomic segments of 118 human papillomavirus type 16 (HPV-16) isolates from 76 cervical biopsy, 14 cervical smear, 3 vulval biopsy, 2 penile biopsy, 2 anal biopsy, and 1 vaginal biopsy sample and two cell lines. The specimens were taken from patients in four countries--Singapore, Brazil, Tanzania, and Germany. The sequence of a 364-bp fragment of the long control region of the virus revealed 38 variants, most of which differed by one or several point mutations. Phylogenetic trees were constructed by distance matrix methods and a transformation series approach. The trees based on the long control region were supported by another set based on the complete E5 protein-coding region. Both sets had two main branches. Nearly all of the variants from Tanzania were assigned to one (African) branch, and all of the German and most of the Singaporean variants were assigned to the other (Eurasian) branch. While some German and Singaporean variants were identical, each group also contained variants that formed unique branches. In contrast to the group-internal homogeneity of the Singaporean, German, and Tanzanian variants, the Brazilian variants were clearly divided between the two branches. Exceptions to this were the seven Singaporean isolates with mutational patterns typical of the Tanzanian isolates. The data suggest that HPV-16 evolved separately for a long period in Africa and Eurasia. Representatives of both branches may have been transferred to Brazil via past colonial immigration. The comparable efficiencies of transfer of the African and the Eurasian variants to the New World suggest pandemic spread of HPV-16 in past centuries. Representatives of the African branch were possibly transferred to the Far East along old Arab and Indonesian sailing routes. Our data also support the view that HPV-16 is a well-defined virus type, since the variants show only a maximal genomic divergence of about 5%. The small amount of divergence in any one geographic location and the lack of marked divergence between the Tanzanian and Brazilian African genome variants two centuries after their likely introduction into the New World suggest a very slow rate of viral evolution. The phylogenetic tree therefore probably represents a minimum of several centuries of evolution, if not an age equal to that of the respective human races.     

The removal response ofApis mellifera L. colonies to brood in wax and plastic cells after artificial and natural infestation withVarroa jacobsoni Oud. and to freeze-killed brood

LikeApis cerana colonies,A. mellifera colonies also show removal response toVarroa-infested brood cells. Infested worker brood cells of artificially and naturally infested combs were detected by the worker bees to various degrees in all types of comb-material used.The bees uncap brood cells and remove larvae or pupae infested with one or two mites. The removal response of worker bees was stronger towards brood cells containing two mites than cells with one mite.The specific signals which cause the removal of brood cells infested withVarroa mites are unknown. Removal response toVarroa-infested brood cells in plastic comb-material (Jenter-and ANP-comb) was significantly higher than to brood in wax combs. Up to now we do not know to what extent this tolerance mechanism is influenced by genetic and environmental factors.Our experiments comparing the removal of freeze-killed brood with the removal of brood infested withVarroa mites demonstrate positive correlations. Considering the time-consuming method of the artificial infestation with living mites, the hygienic behaviour-including the removal of brood cells infested with mites-of large series of colonies can be tested using freeze-killed brood.