Selfing ability and dispersal are positively related, but not affected by range position: a multispecies study on southern African Asteraceae

Dispersal and breeding system traits are thought to affect colonization success. As species have attained their present distribution ranges through colonization, these traits may vary geographically. Although several theories predict associations between dispersal ability, selfing ability and the relative position of a population within its geographic range, there is little theoretical or empirical consensus on exactly how these three variables are related. We investigated relationships between dispersal ability, selfing ability and range position across 28 populations of 13 annual, wind-dispersed Asteraceae species from the Namaqualand region of South Africa. Controlling for phylogeny, relative dispersal ability--assessed from vertical fall time of fruits--was positively related to an index of autofertility--determined from hand-pollination experiments. These findings support the existence of two discrete syndromes: high selfing ability associated with good dispersal and obligate outcrossing associated with lower dispersal ability. This is consistent with the hypothesis that selection for colonization success drives the evolution of an association between these traits. However, no general effect of range position on dispersal or breeding system traits was evident. This suggests selection on both breeding system and dispersal traits acts consistently across distribution ranges.

A survey of U.S. obstetrician-gynecologists' clinical and epidemiological knowledge of cryptosporidiosis in pregnancy

Although cryptosporidiosis is frequently diagnosed in the U.S., there has been very little assessment of obstetrician-gynaecologist knowledge about this disease. In 2010, we surveyed U.S. obstetricians about the diagnosis, treatment and epidemiology of cryptosporidiosis. Data were examined through univariable analysis and multivariable regression models. Of 1000 obstetrician-gynaecologists surveyed, 431 (43.1%) responded. Only 44.4% of respondents correctly identified that prolonged, intermittent diarrhoea would lead them to consider cryptosporidiosis in a differential diagnosis. Routine ova and parasites (O&P) testing was incorrectly chosen to identify Cryptosporidium in stool by 30.4% of respondents. Questions about nitazoxanide, the only drug approved by the U.S. Food & Drug Administration (FDA) for treatment of cryptosporidiosis, were the most frequently missed questions. Only 9.0% of respondents correctly classified nitazoxanide as an FDA pregnancy Category B drug, and only 5.6% of respondents correctly indicated that FDA approved nitazoxanide for immunocompetent patients aged ≥1 years. Regarding prevention- and control-related knowledge, only 14.1% of respondents correctly indicated that alcohol-based hand sanitizers were not effective at inactivating Cryptosporidium spp., and <10% correctly indicated that cryptosporidiosis is a reportable disease in their state of practice. Multivariable analysis found that ≥19 years in practice was positively associated with O&P diagnostic testing knowledge, while rural and urban non-inner city practice location, compared with suburban practice location, was positively associated with nitazoxanide knowledge. The low level of knowledge among obstetrician-gynaecologists about cryptosporidiosis indicates a need to develop resources for physicians about all aspects of cryptosporidiosis, particularly on diagnosis, treatment and prevention strategies.

Endogenous synthesis of n-3 PUFA modifies fatty acid composition of kidney phospholipids and eicosanoid levels in the fat-1 mouse

The goal of the present study was to determine whether endogenous synthesis of n-3 polyunsaturated fatty acids (PUFA) in the fat-1 mouse is comparable to fish oil feeding with respect to kidney n-3 PUFA composition and eicosanoid levels. Wild-type and heterozygous fat-1 mice, capable of synthesizing n-3 PUFA endogenously, were given diets enriched in either n-3 or n-6 PUFA in a 2×2 factorial design and terminated after 12 weeks. Kidney phospholipid fatty acids were analysed by gas chromatography. Kidney eicosanoids were analysed by liquid chromatography tandem mass spectrometry. Relative to control mice fed n-6 PUFA, n-3 PUFA fed and fat-1 mice had higher levels of kidney phospholipid n-3 PUFA, and lower levels of n-6 PUFA and eicosanoids. However, mice fed n-3 PUFA mice had higher levels of n-3 PUFA and lower levels of eicosanoids as compared to fat-1 mice. In conclusion, diet feeding had a greater impact on kidney fatty acid composition and eicosanoid levels than the genetic effect of the fat-1 gene. However, the fat-1 mouse remains a close approximation that can be used as a complementary model to study the role of n-3 PUFA in the kidney.

Bacteriophages lytic for Salmonella rapidly reduce Salmonella contamination on glass and stainless steel surfaces

A cocktail of six lytic bacteriophages, SalmoFresh™, significantly (p < 0.05) reduced the number of surface-applied Salmonella Kentucky and Brandenburg from stainless steel and glass surfaces by > 99% (2.1–4.3 log). Both strains were susceptible to SalmoFresh™ in the spot-test assay. Conversely, SalmoFresh™ was unable to reduce surface contamination with a Salmonella Paratyphi B strain that was not susceptible to the phage cocktail in the spot-test assay. However, by replacing two SalmoFresh™ component phages with two new phages capable of lysing the Paratyphi B strain in the spot-test assay, the target range of the cocktail was shifted to include the Salmonella Paratyphi B strain. The modified cocktail, SalmoLyse™, was able to significantly (p < 0.05) reduce surface contamination of the Paratyphi B strain by > 99% (2.1–4.1 log). The data show that both phage cocktails were effective in significantly reducing the levels of Salmonella on hard surfaces, provided the contaminating strains were susceptible in the spot-test (i.e., spot-test susceptibility was indicative of efficacy in subsequent surface decontamination studies). The data also support the concept that phage preparations can be customized to meet the desired antibacterial application.

Sticky plant captures prey for symbiotic bug: is this digestive mutualism?

Many plants capture and kill insects but, until relatively recently, only carnivorous plants with digestive enzymes were known to gain directly from the nutrients of those insects. Recent studies show that some carnivorous plants lack digestive enzymes and have evolved digestive mutualisms with symbiotic insects that digest their prey for them. Rhododendron macrosepalum, a plant with sticky leaves that captures insects, has an association with symbiotic Mirid bugs that consume the insects captured. Here, we determine what the nature of the relationship is between Mirid and plant. We find that R. macrosepalum has no digestive enzymes of its own but that it does not seem to have the ability to absorb hemipteran faeces through its leaf cuticle. Naturally occurring levels of (15) N and (14) N were used to determine that R. macrosepalum gains no nitrogen through its association with the Mirid bugs and that it obtains all of its nitrogen from the soil. The Mirids, on the other hand, seem to obtain nitrogen from insects captured by the plant, as well as from plant tissues. The relationship between plant and Mirid is not a digestive mutualism but more likely an antagonistic relationship. This study adds to our understanding of how digestive mutualisms evolve and shows that insect capture alone, or in combination with a symbiotic insect relationship does not necessarily make a plant 'carnivorous'.

Sexual risk behavior among HIV-positive patients at an urban clinic in Santiago, Dominican Republic

More than 1% of adults in the Dominican Republic are HIV-infected and most infections are acquired sexually. We studied sexual risk behaviors in a group of HIV-positive patients treated in Santiago, Dominican Republic. Interviews were conducted with 129 participants seen in May 2006 at one of the country's largest public hospital HIV clinics. Questions included demographics, sexual history, condom use, and focused on patients' last sexual encounter. Most patients (72.4%) had been sexually active since their HIV diagnosis. Following their diagnosis, 72.8% of sexually active patients used condoms more frequently, 21.7% used condoms with the same frequency, and 5.4% used condoms less often. The most common reason cited for not using a condom after HIV diagnosis differed by gender; men cited decreased sexual pleasure (70.0%) and women reported that their partner had refused to use a condom (71.8%). Sexually active patients who believed that their partner did not have HIV were much more likely to report using a condom at their last sexual encounter than those who did not know their partner's HIV status (odds ratio [OR] = 16.9). HIV-positive patients reported using condoms more frequently following their HIV diagnosis and were more likely to use a condom if they believed their partner did not have HIV. Increased HIV testing may lead to reduced sexual risk behavior in the Dominican Republic.