Predictors of Attrition and Immunological Failure in HIV-1 Patients on Highly Active Antiretroviral Therapy from Different Healthcare Settings in Mozambique

In Mozambique, the evaluation of retention in HIV care and ART programmes is limited. To assess rate and predictors of attrition (no retention in care) and HAART effectiveness in HIV-1 infected patients who pay for medication and laboratory testing in Mozambique, we conducted a multicenter survey of HIV-1-infected patients who started HAART during 2002–2006. Cox proportional hazard models were used to assess risk of attrition and of therapy failure. Overall, 142 patients from 16 healthcare centers located in the capital city Maputo were followed-up for 22.2 months (12.1–46.7). The retention rate was 75%, 48% and 37% after one, two and three years, respectively. Risk of attrition was lower in patients with higher baseline CD4 count (P = 0.022) and attending healthcare center 1 (HCC1) (P = 0.013). The proportion of individuals with CD4 count ≤200 cells/µL was 55% (78/142) at baseline and decreased to 6% (3/52) at 36 months. Among the patients with available VL, 86% (64/74) achieved undetectable VL levels. The rate of immunologic failure was 17.2% (95% CI: 12.6–22.9) per 100 person-years. Risk of failure was associated to higher baseline CD4 count (P = 0.002), likely reflecting low adherence levels, and decreased with baseline VL ≥10,000 copies/mL (P = 0.033). These results suggest that HAART can be effective in HIV-1 infected patients from Mozambique that pay for their medication and laboratory testing. Further studies are required to identify the causes for low retention rates in patients with low CD4 counts and to better understand the association between healthcare setting and attrition rate.     

Escherichia coli Producing Colibactin Triggers Premature and Transmissible Senescence in Mammalian Cells

Cellular senescence is an irreversible state of proliferation arrest evoked by a myriad of stresses including oncogene activation, telomere shortening/dysfunction and genotoxic insults. It has been associated with tumor activation, immune suppression and aging, owing to the secretion of proinflammatory mediators. The bacterial genotoxin colibactin, encoded by the pks genomic island is frequently harboured by Escherichia coli strains of the B2 phylogenetic group. Mammalian cells exposed to live pks+ bacteria exhibit DNA-double strand breaks (DSB) and undergo cell-cycle arrest and death. Here we show that cells that survive the acute bacterial infection with pks+ E. coli display hallmarks of cellular senescence: chronic DSB, prolonged cell-cycle arrest, enhanced senescence-associated β-galactosidase (SA-β-Gal) activity, expansion of promyelocytic leukemia nuclear foci and senescence-associated heterochromatin foci. This was accompanied by reactive oxygen species production and pro-inflammatory cytokines, chemokines and proteases secretion. These mediators were able to trigger DSB and enhanced SA-β-Gal activity in bystander recipient cells treated with conditioned medium from senescent cells. Furthermore, these senescent cells promoted the growth of human tumor cells. In conclusion, the present data demonstrated that the E. coli genotoxin colibactin induces cellular senescence and subsequently propel bystander genotoxic and oncogenic effects.     

Identification of a Wee1–Like Kinase Gene Essential for Procyclic Trypanosoma brucei Survival

Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases (CDKs). Activation of the cyclin B-cdc2 kinase complex is a pivotal step in mitotic initiation and the tyrosine kinase Wee1 is a key regulator of cell cycle sequence during G2/M transition and inhibits mitotic entry by phosphorylating the inhibitory tyrosine 15 on the cdc2 M-phase-inducing kinase. Wee1 degradation is essential for the exit from the G2 phase. In trypanosomatids, little is known about the genes that regulate cyclin B-cdc2 complexes at the G2/M transition of their cell cycle. Although canonical tyrosine kinases are absent in the genome of trypanosomatids, phosphorylation on protein tyrosine residues has been reported in Trypanosoma brucei. Here, we characterized a Wee1-like protein kinase gene from T. brucei. Expression of TbWee1 in a Schizosaccharomyces pombe strain null for Wee1 inhibited cell division and caused cell elongation. This demonstrates the lengthening of G2, which provided cells with extra time to grow before dividing. The Wee1-like protein kinase was expressed in the procyclic and bloodstream proliferative slender forms of T. brucei and the role of Wee1 in cell cycle progression was analyzed by generating RNA interference cell lines. In the procyclic form of T. brucei, the knock-down of TbWee1 expression by RNAi led to inhibition of parasite growth. Abnormal phenotypes showing an increase in the percentage of cells with 1N0K, 0N1K and 2N1K were observed in these RNAi cell lines. Using parasites with a synchronized cell cycle, we demonstrated that TbWee1 is linked to the G2/M phase. We also showed that TbWee1 is an essential gene necessary for proper cell cycle progression and parasite growth in T. brucei. Our results provide evidence for the existence of a functional Wee1 in T. brucei with a potential role in cell division at G2/M.     

Microarray and RNAi Analysis of P450s in Anopheles gambiae Male and Female Steroidogenic Tissues: CYP307A1 Is Required for Ecdysteroid Synthesis

In insects, the steroid hormone 20-hydroxyecdysone (20E) coordinates major developmental transitions. While the first and the final steps of 20E biosynthesis are characterized, the pathway from 7-dehydrocholesterol to 5β-ketodiol, commonly referred as the “black box”, remains hypothetical and whether there are still unidentified enzymes is unknown. The black box would include some oxidative steps, which are believed to be mediated by P450 enzymes. To identify new enzyme(s) involved in steroid synthesis, we analyzed by small-scale microarray the expression of all the genes encoding P450 enzymes of the malaria mosquito Anopheles gambiae in active steroidogenic organs of adults, ovaries from blood-fed females and male reproductive tracts, compared to inactive steroidogenic organs, ovaries from non-blood-fed females. Some genes encoding P450 enzymes were specifically overexpressed in female ovaries after a blood-meal or in male reproductive tracts but only three genes were found to be overexpressed in active steroidogenic organs of both females and males: cyp307a1, cyp4g16 and cyp6n1. Among these genes, only cyp307a1 has an expression pattern similar to other mosquito steroidogenic genes. Moreover, loss-of-function by transient RNAi targeting cyp307a1 disrupted ecdysteroid production demonstrating that this gene is required for ecdysteroid biosynthesis in Anopheles gambiae.     

Environmentally Enriched Male Mink Gain More Copulations than Stereotypic,Barren-Reared Competitors

Wild carnivores in zoos, conservation breeding centres, and farms commonly live in relatively small, unstimulating enclosures. Under these captive conditions, in a range of species including giant pandas, black-footed ferrets, and European mink, male reproductive abilities are often poor. Such problems have long been hypothesized to be caused by these animals'' housing conditions. We show for the first time that rearing under welfare-improving (i.e., highly valued and stress-reducing) environmental enrichments enhances male carnivores'' copulatory performance: in mate choice competitions, enriched male American mink (Neovison vison) mated more often than non-enriched males. We screened for several potential mediators of this effect. First was physiological stress and its impact on reproductive physiology; second, stress-mediated changes in morphology and variables related to immunocompetence that could influence male attractiveness; and third, behavioural changes likely to affect social competence, particularly autistic-like excessive routine and repetition (‘perseveration’) as is reflected in the stereotypies common in captive animals. Consistent with physiological stress, excreted steroid metabolites revealed that non-enriched males had higher cortisol levels and lower androgen levels than enriched conspecifics. Their os penises (bacula) also tended to be less developed. Consistent with reduced attractiveness, non-enriched males were lighter, with comparatively small spleens and a trend to greater fluctuating asymmetry. Consistent with impaired social competence, non-enriched males performed more stereotypic behaviour (e.g., pacing) in their home cages. Of all these effects, the only significant predictor of copulation number was stereotypy (a trend suggesting that low bodyweights may also be influential): highly stereotypic males gained the fewest copulations. The neurophysiological changes underlying stereotypy thus handicap males sexually. We hypothesise that such males are abnormally perseverative when interacting with females. Investigating similar problems in other taxa would be worthwhile, since many vertebrates, wild and domestic, live in conditions that cause stereotypic behaviour and/or impair neurological development.     

Venezuelan Equine Encephalitis Viruses (VEEV) in Argentina: Serological Evidence of Human Infection

Venezuelan equine encephalitis viruses (VEEV) are responsible for human diseases in the Americas, producing severe or mild illness with symptoms indistinguishable from dengue and other arboviral diseases. For this reason, many cases remain without certain diagnosis. Seroprevalence studies for VEEV subtypes IAB, ID, IF (Mosso das Pedras virus; MDPV), IV (Pixuna virus; PIXV) and VI (Rio Negro virus; RNV) were conducted in persons from Northern provinces of Argentina: Salta, Chaco and Corrientes, using plaque reduction neutralization test (PRNT). RNV was detected in all studied provinces. Chaco presented the highest prevalence of this virus (14.1%). Antibodies against VEEV IAB and -for the first time- against MDPV and PIXV were also detected in Chaco province. In Corrientes, seroprevalence against RNV was 1.3% in the pediatric population, indicating recent infections. In Salta, this was the first investigation of VEEV members, and antibodies against RNV and PIXV were detected. These results provide evidence of circulation of many VEE viruses in Northern Argentina, showing that surveillance of these infectious agents should be intensified.     

Interruption of Transmission of Onchocerca volvulus in the Southern Chiapas Focus,México

Background

The Southern Chiapas focus of onchocerciasis in Southern Mexico represents one of the major onchocerciasis foci in Latin America. All 559 endemic communities of this focus have undergone semi-annual mass treatment with ivermectin since 1998. In 50 communities of this focus, ivermectin frequency shifted from twice to four times a year in 2003; an additional 113 communities were added to the quarterly treatment regimen in 2009 to achieve a rapid suppression of transmission.

Methodology/Principal findings

In-depth epidemiologic and entomologic assessments were performed in six sentinel communities (which had undergone 2 rounds of ivermectin treatment per year) and three extra-sentinel communities (which had undergone 4 rounds of ivermectin treatment per year). None of the 67,924 Simulium ochraceum s.l. collected from this focus during the dry season of 2011 were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in an upper bound of the 95% confidence interval (95%-ULCI) of the infective rate in the vectors of 0.06/2,000 flies examined. Serological assays testing for Onchocerca volvulus exposure conducted on 4,230 children 5 years of age and under (of a total population of 10,280 in this age group) revealed that 2/4,230 individuals were exposed to O. volvulus (0.05%; one sided 95% confidence interval = 0.08%).

Conclusions/Significance

The in-depth epidemiological and entomological findings from the Southern Chiapas focus meet the criteria for interruption of transmission developed by the international community.     

Pistil Starch Reserves at Anthesis Correlate with Final Flower Fate in Avocado (Persea americana)

A common observation in different plant species is a massive abscission of flowers and fruitlets even after adequate pollination, but little is known as to the reason for this drop. Previous research has shown the importance of nutritive reserves accumulated in the flower on fertilization success and initial fruit development but direct evidence has been elusive. Avocado (Persea americana) is an extreme case of a species with a very low fruit to flower ratio. In this work, the implications of starch content in the avocado flower on the subsequent fruit set are explored. Firstly, starch content in individual ovaries was analysed from two populations of flowers with a different fruit set capacity showing that the flowers from the population that resulted in a higher percentage of fruit set contained significantly more starch. Secondly, in a different set of flowers, the style of each flower was excised one day after pollination, once the pollen tubes had reached the base of the style, and individually fixed for starch content analysis under the microscope once the fate of its corresponding ovary (that remained in the tree) was known. A high variability in starch content in the style was found among flowers, with some flowers having starch content up to 1,000 times higher than others, and the flowers that successfully developed into fruits presented significantly higher starch content in the style at anthesis than those that abscised. The relationship between starch content in the ovary and the capacity of set of the flower together with the correlation found between the starch content in the style and the fate of the ovary support the hypothesis that the carbohydrate reserves accumulated in the flower at anthesis are related to subsequent abscission or retention of the developing fruit.