The Contribution of Emotional Partners to Sexual Risk Taking and Violence among Female Sex Workers in Mombasa,Kenya: A Cohort Study

Objectives

To assess sexual risk-taking of female sex workers (FSWs) with emotional partners (boyfriends and husbands), compared to regular and casual clients. Experiences of violence and the degree of relationship control that FSWs have with emotional partners are also described.

Design

Cohort study with quarterly follow-up visit over 12-months.

Methods

Four hundred HIV-uninfected FSWs older than 16 years were recruited from their homes and guesthouses in Mombasa, Kenya. A structured questionnaire assessed participant characteristics and study outcomes at each visit, and women received risk-reduction counselling, male and female condoms, and HIV testing.

Results

Four or more unprotected sex acts in the past week were reported by 21.3% of women during sex with emotional partners, compared to 5.8% with regular and 4.8% with casual clients (P<0.001). Total number of unprotected sex acts per week was 5–6-fold higher with emotional partners (603 acts with 259 partners) than with regular or casual clients (125 acts with 456, and 98 acts with 632 clients, respectively; P<0.001). Mostly, perceptions of “trust” underscored unprotected sex with emotional partners. Low control over these relationships, common to many women (36.9%), was linked with higher partner numbers, inconsistent condom use, and being physically forced to have sex by their emotional partners. Half experienced sexual or physical violence in the past year, similarly associated with partner numbers and inconsistent condom use.

Conclusions

High-risk sexual behaviour, low control and frequent violence in relationships with emotional partners heighten FSWs'' vulnerability and high HIV risk, requiring targeted interventions that also encompass emotional partners.     

UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili

Archaea, like bacteria and eukaryotes, contain proteins involved in various mechanisms of DNA repair, highlighting the importance of these processes for all forms of life. Species of the order Sulfolobales of hyperthermophilic crenarchaeota are equipped with a strongly UV-inducible type IV pilus system that promotes cellular aggregation. Here we demonstrate by fluorescence in situ hybridization that cellular aggregates are formed based on a species-specific recognition process and that UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency. Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Knockout strains of Sulfolobus acidocaldarius incapable of pilus production could not self-aggregate, but were partners in mating experiments with wild-type strains indicating that one cellular partner can mediate the DNA transfer. Since pilus knockout strains showed decreased survival upon UV treatment, we conclude that the UV-inducible DNA transfer process and subsequent homologous recombination represents an important mechanism to maintain chromosome integrity in Sulfolobus. It might also contribute substantially to the frequent chromosomal DNA exchange and horizontal gene transfer in these archaea in their natural habitat.     

Use of benthic vs planktonic organic matter by sandy-beach organisms: A food tracing experiment with C labelled diatoms

Benthic diatoms are assumed to be of minor importance as food sources in sandy-beach food webs, since they are typically scarce in sandy-beach sediments; whereas organic matter derived from land and sea is known to be more important in sandy-beach food webs. In order to test if benthic and planktonic diatoms play a minor or major role, respectively, in sandy-beach food webs, a laboratory experiment was conducted. Labelled planktonic and benthic diatoms, enriched in the stable carbon ¹³C isotope, were offered as food sources to sandy-beach macrofauna and meiofauna communities. Uptake of both types of diatoms occurred with most of the species, but benthic diatoms were preferentially consumed by two macrofaunal species and all meiofaunal species. This result reveals the importance of benthic carbon sources in both macrofaunal and interstitial food webs, and suggests a link between both food webs through the common use of benthic diatoms.     

Separase, securin and Rad21 in neural cell growth

The key mitotic regulator securin is expressed at low levels in fetal brain compared with adult, and modulates the proliferation of human embryonic neuronal N-Tera2 (NT2) cells. We now examine the function and expression of securin's interacting partner separase, along with Rad21, the functional component of cohesin, which is cleaved by separase following interaction with securin. In contrast to securin, the cleaved forms of separase and Rad21 were highly expressed in human fetal cerebral cortex compared with adult. In a murine model of absent securin expression - the PTTG knock-out mouse - separase and Rad21 were over-expressed in multiple brain regions. In addition, cDNA array analysis of other key mitotic regulators additionally identified cyclin C and sestrin 2 to be induced in the brains of securin-null mice compared with wild type. Further, Rad21 mRNA expression was highly correlated with that of securin, separase, cyclin C and sestrin 2 in fetal brains. In embryonic neuronal NT2 cells, siRNA repression of separase failed to significantly alter cell turnover, whereas repression of securin expression resulted in increased levels of the activated forms of Rad21 and separase, and promoted cell proliferation. Our data suggest that the co-ordinated expression of separase, securin and Rad21 is fundamental for the developing brain.     

Development of the osteocranium in the suckermouth armored catfish Ancistrus cf. triradiatus (Loricariidae, siluriformes)

The development of the osteocranium of the suckermouth armored catfish Ancistrus cf. triradiatus is described based on specimens ranging from prehatching stages to juvenile stages where the osteocranium is more or less fully formed. The first bony elements that arise are the opercle, jaws, and lateralmost branchiostegal rays, as well as the basioccipital and parasphenoid in the skull floor. The supracleithrum and the membranous and perichondral pterotic components form one large, double-layered skull bone during ontogeny, without clear evidence of the involvement of a supratemporal. The Baudelot's ligament ossifies from two sides, i.e., from the basioccipital medially and the supracleithrum laterally. The lower jaw consists of a dentary, mentomeckelian, and angulo-articular, which all soon fuse. The parurohyal, formed by the fusion of a ventral sesamoid bone and a dorsal cartilage element associated with the first basibranchial, is pierced by a vein, unlike in some other siluriforms. The interhyal cartilage disappears during ontogeny; medially of it, a small sesamoid bone appears in a ligament. The largest, canal-bearing cheek plate is not homologous to the interopercle. The results of the present research, with emphasis on bone formations and homologies, are compared with studies on related catfishes.     

Expression, purification and characterization of full-length RNA-free hepatitis B core particles

The nucleocapsid or core particle of the hepatitis B virus has become one of the favourite recombinant vaccine carriers for foreign peptides, proteins and stimulatory oligonucleotides. The core protein consists of three regions: an N-terminal, a central and a C-terminal region that can accommodate the addition or insertion of the foreign sequences. The protamine-like C-terminal region that binds host RNA randomly during recombinant particle formation is often truncated. It is commonly thought that these truncations do not affect particle assembly. Recent studies have demonstrated that the C-terminal domains mediate a glycosaminoglycan-dependent attachment of nucleocapsids to the plasma membranes of host cells. This interaction might well contribute to the immunogenicity of nucleocapsids. Testing the hypothesis that full-length particles might be safer and superior for the induction of an immune response against the nucleocapsids and inserted sequences, requires the availability of purified particles. In this report, we detail a novel method for the synthesis and purification of full-length core particles essentially free of RNA from Escherichia coli.     

A novel mutation in Slc2a4 as a mouse model of fatigue

Chronic fatigue is a debilitating disorder with widespread consequences, but effective treatment strategies are lacking. Novel genetic mouse models of fatigue may prove invaluable for studying its underlying physiological mechanisms and for testing treatments and interventions. In a screen of voluntary wheel‐running behavior in N‐ethyl‐N‐nitrosourea mutagenized C57BL/6J mice, we discovered two lines with low body weights and aberrant wheel‐running patterns suggestive of a fatigue phenotype. Affected progeny from these lines had lower daily activity levels and exhibited low amplitude circadian rhythm alterations. Their aberrant behavior was characterized by frequent interruptions and periods of inactivity throughout the dark phase of the light‐dark cycle and increased levels of activity during the rest or light phase. Expression of the behavioral phenotypes in offspring of strategic crosses was consistent with a recessive inheritance pattern. Mapping of phenotypic abnormalities showed linkage with a single locus on chromosome 1, and whole exome sequencing identified a single point mutation in the Slc2a4 gene encoding the GLUT4 insulin‐responsive glucose transporter. The single nucleotide change (A‐T, which we named “twiggy”) was in the distal end of exon 10 and resulted in a premature stop (Y440*). Additional metabolic phenotyping confirmed that these mice recapitulate phenotypes found in GLUT4 knockout mice. However, to the best of our knowledge, this is the first time a mutation in this gene has been shown to result in extensive changes in general behavioral patterns. These findings suggest that GLUT4 may be involved in circadian behavioral abnormalities and could provide insights into fatigue in humans.