The Protector Species Hypothesis: Do Black Skimmers Find Refuge from Predators in Gull-billed Tern Colonies?

The protector-species hypothesis explains mixed-species coloniality on the basis of benefits individuals of a species may receive by nesting with another species, the ‘protector’ species, that responds aggressively to potential threats. The reactions of nesting individuals to both natural and model predators were observed to determine whether black skimmers (Rhynchops niger) gain an antipredator advantage by nesting with gull-billed terns (Sterna nilotica). Observations of natural predators were gathered from three mixed-species and three single-species (black skimmers) subcolonies. Natural predators most commonly encountered by the colonies were herring gulls (Larus argentatus), laughing gulls (Larus atricilla), and ruddy turnstones (Arenaria interpres). Gull-billed terns responded to the gulls, but not to the turnstones, in higher proportions than did black skimmers. Two decoys, a mink and a gull, were used to simulate predatory encounters, and a duck decoy was used as a control at two mixed-species and one single-species subcolonies. Gull-billed terns responded in significantly higher proportions than did skimmers to all decoy treatments in the mixed-species subcolonies. Mobbing of both natural and model predators by the terns suggests that skimmers may gain a reproductive advantage by nesting with these terns. However, the response of black skimmers to both natural and simulated predators was independent of the presence of gull-billed terns in the colony, indicating that black skimmers may not perceive these objects as threats, or may react differently to predators than do gull-billed terns.     

Novel anti-inflammatory and analgesic agents: synthesis,molecular docking and in vivo studies

Twelve new derivatives of benzothiazole bearing benzenesulphonamide and carboxamide were synthesised and investigated for their in vivo anti-inflammatory, analgesic and ulcerogenic activities. Molecular docking showed an excellent binding interaction of the synthesised compounds with the receptors, with 17c showing the highest binding energy (–12.50?kcal/mol). Compounds 17c and 17i inhibited carrageenan-induced rat paw oedema at 72, 76, and 80% and 64, 73, and 78% at 1?h, 2?h, and 3?h, respectively. In the analgesic activity experiment, compounds 17c, 17?g, and 17i had ED₅₀ (µM/kg) of 96, 127, and 84 after 0.5?h; 102, 134, and 72 after 1?h and 89, 156, and 69 µM/kg after 2?h, respectively, which were comparable with 156, 72, and 70 µM/kg for celecoxib. The ulcerogenic index of the most active derivatives 17c and 17i were 0.82 and 0.89, respectively, comparable to 0.92 for celecoxib. The physicochemical studies of the new derivatives showed that they will not have oral bioavailability problems.     

Effect of trophic status of a deep-water lake on breeding Great Crested Grebes Podiceps cristatus during a phase of recovery from eutrophication: a long-term study

Capsule: Trophic status of a deep-water lake was the main driver of changes in breeding population size of Great Crested Grebes Podiceps cristatus while reproductive success was also strongly affected by weather parameters.

Aims: To determine the effects of changes in nutrient status of a formerly highly-eutrophicated deep-water lake and other environmental parameters on a Great Crested Grebe population during a phase of re-oligotrophication.

Methods: Annual surveys were carried out on a natural lake in Switzerland over a period of 25 years to determine breeding population size and reproductive success. The effects of phosphorus content, other limnological parameters and weather variables were analysed with quasi-Poisson models.

Results: The breeding population increased from 80 pairs in 1992 to 417 pairs in 2001, after which numbers showed strong fluctuations. Total phosphorus content in the lake had a strong negative effect on breeding population size. A significant positive correlation was found with the national population index. Reproductive success fluctuated strongly but showed an overall decline. The model indicated positive effects on reproductive success of phosphorus and negative effects of the number of days with strong wind. Rapid water-level increases in early summer and water transparency in June led to higher proportions of late broods.

Conclusion: Phosphorus concentration was identified as the main driver affecting the breeding population of Great Crested Grebes during the phase of recovery of the lake from a highly-eutrophic state. Results indicate that mesotrophic to eutrophic conditions enabled a large population and high breeding success. Reproductive output was further negatively affected by strong wind during a critical breeding phase.     

Structural Insights into the Lipid A Transport Pathway in MsbA

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Cell spreading and focal adhesion dynamics are regulated by spacing of integrin ligands

Integrin-mediated adhesion is regulated by multiple features of the adhesive surface, including its chemical composition, topography, and physical properties. In this study we investigated integrin lateral clustering, as a mechanism to control integrin functions, by characterizing the effect of nanoscale variations in the spacing between adhesive RGD ligands on cell spreading, migration, and focal adhesion dynamics. For this purpose, we used nanopatterned surfaces, containing RGD-biofunctionalized gold dots, surrounded by passivated gaps. By varying the spacing between the dots, we modulated the clustering of the associated integrins. We show that cell-surface attachment is not sensitive to pattern density, whereas the formation of stable focal adhesions and persistent spreading is. Thus cells plated on a 108-nm-spaced pattern exhibit delayed spreading with repeated protrusion-retraction cycles compared to cells growing on a 58-nm pattern. Cell motility on these surfaces is erratic and nonpersistent, leaving thin membrane tethers bound to the RGD pattern. Dynamic molecular profiling indicated that the adhesion sites formed with the 108-nm pattern undergo rapid turnover and contain reduced levels of zyxin. These findings indicate that a critical RGD density is essential for the establishment of mature and stable integrin adhesions, which, in turn, induce efficient cell spreading and formation of focal adhesions.     

Cost-Effectiveness of Clinical Decision Support System in Improving Maternal Health Care in Ghana

ObjectiveThis paper investigated the cost-effectiveness of a computer-assisted Clinical Decision Support System (CDSS) in the identification of maternal complications in Ghana.MethodsA cost-effectiveness analysis was performed in a before- and after-intervention study. Analysis was conducted from the provider’s perspective. The intervention area was the Kassena- Nankana district where computer-assisted CDSS was used by midwives in maternal care in six selected health centres. Six selected health centers in the Builsa district served as the non-intervention group, where the normal Ghana Health Service activities were being carried out.ResultsComputer-assisted CDSS increased the detection of pregnancy complications during antenatal care (ANC) in the intervention health centres (before-intervention= 9 /1,000 ANC attendance; after-intervention= 12/1,000 ANC attendance; P-value=0.010). In the intervention health centres, there was a decrease in the number of complications during labour by 1.1%, though the difference was not statistically significant (before-intervention =107/1,000 labour clients; after-intervention= 96/1,000 labour clients; P-value=0.305). Also, at the intervention health centres, the average cost per pregnancy complication detected during ANC (cost –effectiveness ratio) decreased from US$17,017.58 (before-intervention) to US$15,207.5 (after-intervention). Incremental cost –effectiveness ratio (ICER) was estimated at US$1,142. Considering only additional costs (cost of computer-assisted CDSS), cost per pregnancy complication detected was US$285.ConclusionsComputer –assisted CDSS has the potential to identify complications during pregnancy and marginal reduction in labour complications. Implementing computer-assisted CDSS is more costly but more effective in the detection of pregnancy complications compared to routine maternal care, hence making the decision to implement CDSS very complex. Policy makers should however be guided by whether the additional benefit is worth the additional cost.     

Occurrence of Antibiotic Resistance Genes and Bacterial Markers in a Tropical River Receiving Hospital and Urban Wastewaters

The occurrence of emerging biological contaminants including antibiotic resistance genes (ARGs) and Faecal Indicator Bacteria (FIB) is still little investigated in developing countries under tropical conditions. In this study, the total bacterial load, the abundance of FIB (E. coli and Enterococcus spp. (ENT)), Pseudomonas spp. and ARGs (bla_TEM, bla_CTX-M, bla_SHV, bla_NDM and aadA) were quantified using quantitative PCR in the total DNA extracted from the sediments recovered from hospital outlet pipes (HOP) and the Cauvery River Basin (CRB), Tiruchirappalli, Tamil Nadu, India. The abundance of bacterial marker genes were 120, 104 and 89 fold higher for the E. coli, Enterococcus spp. and Pseudomonas spp., respectively at HOP when compared with CRB. The ARGs aadA and bla_TEM were most frequently detected in higher concentration than other ARGs at all the sampling sites. The ARGs bla_SHV and bla_NDM were identified in CRB sediments contaminated by hospital and urban wastewaters. The ARGs abundance strongly correlated (r ≥ 0.36, p < 0.05, n = 45) with total bacterial load and E. coli in the sediments, indicating a common origin and extant source of contamination. Tropical aquatic ecosystems receiving wastewaters can act as reservoir of ARGs, which could potentially be transferred to susceptible bacterial pathogens at these sites.     

Mortality in sickle cell anemia in Africa: a prospective cohort study in Tanzania

Background

The World Health Organization has declared Sickle Cell Anemia (SCA) a public health priority. There are 300,000 births/year, over 75% in Africa, with estimates suggesting that 6 million Africans will be living with SCA if average survival reaches half the African norm. Countries such as United States of America and United Kingdom have reduced SCA mortality from 3 to 0.13 per 100 person years of observation (PYO), with interventions such as newborn screening, prevention of infections and comprehensive care, but implementation of interventions in African countries has been hindered by lack of locally appropriate information. The objective of this study was to determine the incidence and factors associated with death from SCA in Dar-es-Salaam.

Methods and Findings

A hospital-based cohort study was conducted, with prospective surveillance of 1,725 SCA patients recruited from 2004 to 2009, with 209 (12%) lost to follow up, while 86 died. The mortality rate was 1.9 (95%CI 1.5, 2.9) per 100 PYO, highest under 5-years old [7.3 (4.8–11.0)], adjusting for dates of birth and study enrollment. Independent risk factors, at enrollment to the cohort, predicting death were low hemoglobin (<5 g/dL) [3.8 (1.8–8.2); p = 0.001] and high total bilirubin (≥102 µmol/L) [1.7 (1.0–2.9); p = 0.044] as determined by logistic regression.

Conclusions

Mortality in SCA in Africa is high, with the most vulnerable period being under 5-years old. This is most likely an underestimate, as this was a hospital cohort and may not have captured SCA individuals with severe disease who died in early childhood, those with mild disease who are undiagnosed or do not utilize services at health facilities. Prompt and effective treatment for anemia in SCA is recommended as it is likely to improve survival. Further research is required to determine the etiology, pathophysiology and the most appropriate strategies for management of anemia in SCA.