Climate‐driven changes to the spatio‐temporal distribution of the parasitic nematode,Haemonchus contortus,in sheep in Europe

Recent climate change has resulted in changes to the phenology and distribution of invertebrates worldwide. Where invertebrates are associated with disease, climate variability and changes in climate may also affect the spatio‐temporal dynamics of disease. Due to its significant impact on sheep production and welfare, the recent increase in diagnoses of ovine haemonchosis caused by the nematode Haemonchus contortus in some temperate regions is particularly concerning. This study is the first to evaluate the impact of climate change on H. contortus at a continental scale. A model of the basic reproductive quotient of macroparasites, Q₀, adapted to H. contortus and extended to incorporate environmental stochasticity and parasite behaviour, was used to simulate Pan‐European spatio‐temporal changes in H. contortus infection pressure under scenarios of climate change. Baseline Q₀ simulations, using historic climate observations, reflected the current distribution of H. contortus in Europe. In northern Europe, the distribution of H. contortus is currently limited by temperatures falling below the development threshold during the winter months and within‐host arrested development is necessary for population persistence over winter. In southern Europe, H. contortus infection pressure is limited during the summer months by increased temperature and decreased moisture. Compared with this baseline, Q₀ simulations driven by a climate model ensemble predicted an increase in H. contortus infection pressure by the 2080s. In northern Europe, a temporal range expansion was predicted as the mean period of transmission increased by 2–3 months. A bimodal seasonal pattern of infection pressure, similar to that currently observed in southern Europe, emerges in northern Europe due to increasing summer temperatures and decreasing moisture. The predicted patterns of change could alter the epidemiology of H. contortus in Europe, affect the future sustainability of contemporary control strategies, and potentially drive local adaptation to climate change in parasite populations.     

The Network of Knowledge approach: improving the science and society dialogue on biodiversity and ecosystem services in Europe

The absence of a good interface between scientific and other knowledge holders and decision-makers in the area of biodiversity and ecosystem services has been recognised for a long time. Despite recent advancements, e.g. with the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), challenges remain, particularly concerning the timely provision of consolidated views from different knowledge domains. To address this challenge, a strong and flexible networking approach is needed across knowledge domains and institutions. Here, we report on a broad consultation process across Europe to develop a Network of Knowledge on biodiversity and ecosystem services (NoK), an approach aiming at (1) organising institutions and knowledge holders in an adaptable and responsive framework and (2) informing decision-makers with timely and accurate biodiversity knowledge. The consultation provided a critical analysis of the needs that should be addressed by a NoK and how it could complement existing European initiatives and institutions at the interface between policy and science. Among other functions, the NoK provides consolidated scientific views on contested topics, identification of research gaps to support relevant policies, and horizon scanning activities to anticipate emerging issues. The NoK includes a capacity building component on interfacing activities and contains mechanisms to ensure its credibility, relevance and legitimacy. Such a network would need to ensure credibility, relevance and legitimacy of its work by maximizing transparency and flexibility of processes, quality of outputs, the link to data and knowledge provision, the motivation of experts for getting involved and sound communication and capacity building.     

Genetic diversity and gene flow between wild, cultivated and weedy forms of Beta vulgaris L. (Chenopodiaceae), assessed by RFLP and microsatellite markers

 Beets belonging to the species Beta vulgaris L. can be found in crop, wild and weedy forms, all of which are interfertile. We studied the intra-specific genetic relationships of about 300 individuals from 54 populations of various French geographic origins using nuclear molecular markers (five single-copy RFLP loci and one microsatellite locus). The patterns of diversity were congruent for both types of markers. Genetic diversity in wild beets appeared to be high, both in term of allele number and observed heterozygosity, whereas the narrowness of the cultivated-beet gene pool was confirmed. Genetic distances between all forms showed that weed beets in northern France are intermediates between sugar beet and inland wild beets in south-western France. This analysis allowed us to infer the paternal origin of weed beets and furthermore, is in agreement with a previous study which focused on their maternal origin: weed beet infesting sugar-beet fields originated from accidental and recurrent hybridization between cultivated lines and ruderal inland wild beets during the production of commercial seeds in south-western France. Inland wild beets are genetically close to Mediterranean coastal wild beets, but differ from other coastal forms (from Biscay, Brittany and northern France). The study of gene flow in the beet complex contributes to the risk assessment of transgenic beets. Received: 8 June 1998 / Accepted: 8 October 1998     

Levels of extra‐pair paternity are associated with parental care in penduline tits (Remizidae)

In most passerine birds, individuals attempt to maximize their fitness by providing parental care while also mating outside their pair bond. A sex‐specific trade‐off between these two behaviours is predicted to occur, as the fitness benefits of extra‐pair mating differ between the sexes. We use nest observations and parentage analysis to reveal a negative association between male care and the incidence of extra‐pair paternity across three species of penduline tit (Remizidae). This provides evidence of a trade‐off between these two behaviours, possibly due to the devaluing of paternal care by extra‐pair offspring.     

Carbohydrate metabolism is perturbed in peroxisome-deficient hepatocytes due to mitochondrial dysfunction, AMP-activated protein kinase (AMPK) activation, and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) suppression

Hepatic peroxisomes are essential for lipid conversions that include the formation of mature conjugated bile acids, the degradation of branched chain fatty acids, and the synthesis of docosahexaenoic acid. Through unresolved mechanisms, deletion of functional peroxisomes from mouse hepatocytes (L-Pex5(-/-) mice) causes severe structural and functional abnormalities at the inner mitochondrial membrane. We now demonstrate that the peroxisomal and mitochondrial anomalies trigger energy deficits, as shown by increased AMP/ATP and decreased NAD(+)/NADH ratios. This causes suppression of gluconeogenesis and glycogen synthesis and up-regulation of glycolysis. As a consequence, L-Pex5(-/-) mice combust more carbohydrates resulting in lower body weights despite increased food intake. The perturbation of carbohydrate metabolism does not require a long term adaptation to the absence of functional peroxisomes as similar metabolic changes were also rapidly induced by acute elimination of Pex5 via adenoviral administration of Cre. Despite its marked activation, peroxisome proliferator-activated receptor α (PPARα) was not causally involved in these metabolic perturbations, because all abnormalities still manifested when peroxisomes were eliminated in a peroxisome proliferator-activated receptor α null background. Instead, AMP-activated kinase activation was responsible for the down-regulation of glycogen synthesis and induction of glycolysis. Remarkably, PGC-1α was suppressed despite AMP-activated kinase activation, a paradigm not previously reported, and they jointly contributed to impaired gluconeogenesis. In conclusion, lack of functional peroxisomes from hepatocytes results in marked disturbances of carbohydrate homeostasis, which are consistent with adaptations to an energy deficit. Because this is primarily due to impaired mitochondrial ATP production, these L-Pex5-deficient livers can also be considered as a model for secondary mitochondrial hepatopathies.     

Availability of Volunteer-Led Home-Based Care System and Baseline Factors as Predictors of Clinical Outcomes in HIV-Infected Patients in Rural Zambia

Background

We assessed the impact of home-based care (HBC) for HIV+ patients, comparing outcomes between two groups of Zambians receiving antiretroviral therapy (ART) who lived in villages with and without HBC teams.

Methods

We conducted a retrospective cohort study using medical charts from Macha Mission Hospital, a hospital providing HIV care in Zambia''s rural Southern Province. Date of birth, date of ART initiation, place of residence, sex, body mass index (BMI), CD4+ cell count, and hemoglobin (Hgb) were abstracted. Logistic regression was used to test our hypothesis that HBC was associated with treatment outcomes.

Results

Of 655 patients, 523 (80%) were eligible and included in the study. There were 428 patients (82%) with favorable outcomes (alive and on ART) and 95 patients (18%) with unfavorable outcomes (died, lost to follow-up, or stopped treatment). A minority of the 523 eligible patients (n = 84, 16%) lived in villages with HBC available. Living in a village with HBC was not significantly associated with treatment outcomes; 80% of patients in a village with HBC had favorable outcomes, compared to 82% of patients in a village without HBC (P = 0.6 by χ²). In bivariable analysis, lower BMI (P<0.001), low CD4+ cell count (P = 0.02), low Hgb concentration (P = 0.02), and older age at ART initiation (P = 0.047) were associated with unfavorable outcomes. In multivariable analysis, low BMI remained associated with unfavorable outcomes (P<0.001).

Conclusions

We did not find that living in a village with HBC available was associated with improved treatment outcomes. We speculate that the ART clinic''s rigorous treatment preparation before ART initiation and continuous adherence counseling during ART create a motivated group of patients whose outcomes did not improve with additional HBC support. An alternative explanation is that the quality of the HBC program is suboptimal.     

Different anthropometric adiposity measures and their association with cardiovascular disease risk factors: a meta-analysis

Objectives

To investigate which anthropometric adiposity measure has the strongest association with cardiovascular disease (CVD) risk factors in Caucasian men and women without a history of CVD.

Design

Systematic review and meta-analysis.

Methods

We searched databases for studies reporting correlations between anthropometric adiposity measures and CVD risk factors in Caucasian subjects without a history of CVD. Body mass index (BMI), waist circumference, waist-to-hip ratio, waist-to-height ratio and body fat percentage were considered the anthropometric adiposity measures. Primary CVD risk factors were: systolic blood pressure, diastolic blood pressure, high density lipoprotein (HDL) cholesterol, triglycerides and fasting glucose. Two independent reviewers performed abstract, full text and data selection.

Results

Twenty articles were included describing 21,618 males and 24,139 females. Waist circumference had the strongest correlation with all CVD risk factors for both men and women, except for HDL and LDL in men. When comparing BMI with waist circumference, the latter showed significantly better correlations to CVD risk factors, except for diastolic blood pressure in women and HDL and total cholesterol in men.

Conclusions

We recommend the use of waist circumference in clinical and research studies above other anthropometric adiposity measures, especially compared with BMI, when evaluating CVD risk factors.     

Dynamics and attenuation characteristics of periphyton upon artificial substratum under various light conditions and some additional observations on periphyton upon Potamogeton pectinatus L.

The seasonal variation in periphyton dynamics has been studied upon artificial substratum (microscopic glass slides) under various light conditions during the periods May–October 1986 and May–September 1987, in Lake Veluwe. Some additional observations on the periphyton development upon leaves of Potamogeton pectinatus L. have been made simultaneously. Four different light conditions were created in an experimental setup by manipulating the photon flux density through artificial shading.Periphyton upon artificial substratum exhibited a relatively high abundance with a distinct seasonal pattern. Periphyton accrual rates were highest at the beginning of June and in August and September upon slides which were incubated for two weeks. Periphyton mass increased during May and June, decreased or remained about the same during July and subsequently increased until an upper plateau was reached upon slides which were incubated from the beginning of May onwards.Generally, periphyton mass was lower upon slides than upon P. pectinatus. The seasonal variation in periphyton mass was more pronounced upon P. pectinatus leaves than upon the slides.Attenuation by periphyton upon slides ranged from 5 to 65% after two weeks of incubation. Periphyton upon slides which had been incubated for more than two weeks demonstrated an attenuation of more than 85%.Water quality parameters other than photon flux density were probably more important in determining the periphyton dynamics, since only minor differences were observed in periphyton mass between the various light conditions. Chlorophyll-a content was higher with increased shading on various sampling dates.Periphyton, especially older periphyton consisted largely of settled silt and clay particles and to a lesser extent of detrital matter on both substrata. Living epiphytes were only a relatively small fraction.It is concluded that a reduction of resuspension of sediment particles, giving less suspended matter in the water column, will result in lower periphytic mass. Consequently, the quantity of photosynthetically active radiation reaching the submerged macrophytes is expected to increase considerably.     

Electron microscopic study of DNA complexes with proteins from the Archaebacterium Sulfolobus acidocaldarius

DNA-protein complexes formed in vitro with isolated DNA-binding proteins from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius were analyzed by electron microscopy. Two of the proteins (10a and 10b) formed specific structures after incubation with DNA. Protein 10a, at low protein concentrations, showed individual small spots on the DNA and at high concentrations evenly covered doublestranded DNA. Protein 10b showed three different types of regular structures: one with single-stranded and two with double-stranded DNA. Using double-stranded DNA, 10b first bound cooperatively to two strands forming long, plait-like structures only slightly shorter than respective free DNA. The complex consists of two right-handed, interwound fibers, with a helical pitch of 26 nm and a diameter of ~10-11 nm. At higher protein concentration than needed to package all DNA into the complex with two double-stranded DNAs, the two DNAs were separated again and a new structure was formed evenly covering only one DNA strand. Both structures showed no significant contraction of the length of the DNA covered in the complex. Nucleoprotein formed with single-stranded ΦX174 DNA had a diameter of ~11 nm and could form circles with a contour length of 0.5 μm.