An attempt to correlate cattle breed origins and diseases associated with or transmitted by the tick Amblyomma variegatum in the French West Indies

A l'aide de données biologiques et de la recherche historique, on a essayé d'expliquer la différence, en ce qui concerne la résistance et la sensibilité aux maladies transmises par (cowdriose) ou associées à (dermatophilose) la tique Amblyomma variegatum, entre deux races bovines des Antilles françaises : la race Créole hybride de la Guadeloupe et le zébu Brahman de la Martinique. Les polymorphismes de 5 systèmes génétiques indépendants (hémoglobine érythrocytaire, albumine et transferrine du sérum, la région classe I du complexe BolA et le gène gamma S cristallin) ont été étudiés chez différentes races, à savoir des Bos taurus d'Europe et d'Afrique, des Bos indicus d'Afrique de l'Ouest et de l'Est, le Brahamn de la Martinique et le Créole de la Guadeloupe. Par comparaison des fréquences de différents allèles de ces 5 loci polymorphiques non liés et à l'aide de deux matrices mathématiques différentes de NEI et de CAVALLI-SFORZA, on a établi les distances génétiques entre ces races. Il apparaît clairement que le bovin Créole de la Guadeloupe est dans une position intermédiaire entre le Bos taurus N'Dama de l'Afrique de l'Ouest et le Brahma

Mycolactone Diffuses into the Peripheral Blood of Buruli Ulcer Patients - Implications for Diagnosis and Disease Monitoring.

BACKGROUND: Mycobacterium ulcerans, the causative agent of Buruli ulcer (BU), is unique among human pathogens in its capacity to produce a polyketide-derived macrolide called mycolactone, making this molecule an attractive candidate target for diagnosis and disease monitoring. Whether mycolactone diffuses from ulcerated lesions in clinically accessible samples and is modulated by antibiotic therapy remained to be established. METHODOLOGY/PRINCIPAL FINDING: Peripheral blood and ulcer exudates were sampled from patients at various stages of antibiotic therapy in Ghana and Ivory Coast. Total lipids were extracted from serum, white cell pellets and ulcer exudates with organic solvents. The presence of mycolactone in these extracts was then analyzed by a recently published, field-friendly method using thin layer chromatography and fluorescence detection. This approach did not allow us to detect mycolactone accurately, because of a high background due to co-extracted human lipids. We thus used a previously established approach based on high performance liquid chromatography coupled to mass spectrometry. By this means, we could identify structurally intact mycolactone in ulcer exudates and serum of patients, and evaluate the impact of antibiotic treatment on the concentration of mycolactone. CONCLUSIONS/SIGNIFICANCE: Our study provides the proof of concept that assays based on mycolactone detection in serum and ulcer exudates can form the basis of BU diagnostic tests. However, the identification of mycolactone required a technology that is not compatible with field conditions and point-of-care assays for mycolactone detection remain to be worked out. Notably, we found mycolactone in ulcer exudates harvested at the end of antibiotic therapy, suggesting that the toxin is eliminated by BU patients at a slow rate. Our results also indicated that mycolactone titres in the serum may reflect a positive response to antibiotics, a possibility that it will be interesting to examine further through longitudinal studies

Combined Inflammatory and Metabolic Defects Reflected by Reduced Serum Protein Levels in Patients with Buruli Ulcer Disease

Buruli ulcer is a skin disease caused by Mycobacterium ulcerans that is spreading in tropical countries, with major public health and economic implications in West Africa. Multi-analyte profiling of serum proteins in patients and endemic controls revealed that Buruli ulcer disease down-regulates the circulating levels of a large array of inflammatory mediators, without impacting on the leukocyte composition of peripheral blood. Notably, several proteins contributing to acute phase reaction, lipid metabolism, coagulation and tissue remodelling were also impacted. Their down-regulation was selective and persisted after the elimination of bacteria with antibiotic therapy. It involved proteins with various functions and origins, suggesting that M. ulcerans infection causes global and chronic defects in the host’s protein metabolism. Accordingly, patients had reduced levels of total serum proteins and blood urea, in the absence of signs of malnutrition, or functional failure of liver or kidney. Interestingly, slow healers had deeper metabolic and coagulation defects at the start of antibiotic therapy. In addition to providing novel insight into Buruli ulcer pathogenesis, our study therefore identifies a unique proteomic signature for this disease

Causes of variation in BCG vaccine efficacy: examining evidence from the BCG REVAC cluster randomized trial to explore the masking and the blocking hypotheses.

BCG protection varies and in some places (nearest the equator) is low or absent. Understanding this variation can inform the efforts to develop new vaccines against tuberculosis. Two main hypotheses are used to explain this variation: under masking, new vaccines are unlikely to increase protection; under blocking new vaccines have a greater potential to be effective when BCG is not. We conducted a cluster randomized trial to explored the masking and blocking hypotheses by studying BCG vaccine efficacy of neonatal vaccination and when administered for the first or a second (revaccination) time at school age in two sites (Manaus close and Salvador further south from the equator). Seven hundred and sixty three state schools were matched on socio economic characteristics of the neighborhood and 239,934 children were randomized to vaccine (BCG vaccination at school age) or control group. Protection by first BCG vaccination at school age was high in Salvador (34%, 95% CI 7-53%, p=0.017) but low in Manaus (8%, 95% CI t0 39-40%, p=0.686). For revaccination at school age, protection was modest in Salvador (19%, 95% CI 3-33%, p=0.022) and absent in Manaus (1%, 95% CI to 27-23%, p=0.932). Vaccine efficacy for neonatal vaccination was similar in Salvador (40%, 95% CI 22-54%, p<0.001) and Manaus (36%, 95% CI 11-53%, p=0.008). Variation in BCG efficacy was marked when vaccine was given at school age but absent at birth, which points towards blocking as the dominant mechanism. New tuberculosis vaccines that overcome or by pass this blocking effect could confer protection in situations where BCG is not protective

Electron transfer ferredoxins with unusual cluster binding motifs support secondary metabolism in many bacteria

The proteins responsible for controlling electron transfer in bacterial secondary metabolism are not always known or characterised. Here we demonstrate that many bacteria contain a set of unfamiliar ferredoxin encoding genes which are associated with those of cytochrome P450 (CYP) monooxygenases and as such are involved in anabolic and catabolic metabolism. The model organism Mycobacterium marinum M contains eleven of these genes which encode [3Fe–4S] or [4Fe–4S] single cluster containing ferredoxins but which have unusual iron–sulfur cluster binding motif sequences, CXX?XXC(X)nCP, where ‘?’ indicates a variable amino acid residue. Rather than a cysteine residue, which is highly conserved in [4Fe–4S] clusters, or alanine or glycine residues, which are common in [3Fe–4S] ferredoxins, these genes encode at this position histidine, asparagine, tyrosine, serine, threonine or phenylalanine. We have purified, characterised and reconstituted the activity of several of these CYP/electron transfer partner systems and show that all those examined contain a [3Fe–4S] cluster. Furthermore, the ferredoxin used and the identity of the variable motif residue in these proteins affects the functionality of the monooxygenase system and has a significant influence on the redox properties of the ferredoxins. Similar ferredoxin encoding genes were identified across Mycobacterium species, including in the pathogenic M. tuberculosis and M. ulcerans, as well as in a wide range of other bacteria such as Rhodococcus and Streptomyces. In the majority of instances these are associated with CYP genes. These ferredoxin systems are important in controlling electron transfer across bacterial secondary metabolite production processes which include antibiotic and pigment formation among others

IFN-γ and IL-5 whole blood response directed against mycolactone polyketide synthase domains in patients with Mycobacterium ulcerans infection.

Background: Buruli ulcer is a disease of the skin and soft tissues caused by infection with a slow growing pathogen, Mycobacterium ulcerans. A vaccine for this disease is not available but M. ulcerans possesses a giant plasmid pMUM001 that harbours the polyketide synthase (PKS) genes encoding a multi-enzyme complex needed for the production of its unique lipid toxin called mycolactone, which is central to the pathogenesis of Buruli ulcer. We have studied the immunogenicity of enzymatic domains in humans with M. ulcerans disease, their contacts, as well as non-endemic areas controls. Methods: Between March 2013 and August 2015, heparinized whole blood was obtained from patients confirmed with Buruli ulcer. The blood samples were diluted 1 in 10 in Roswell Park Memorial Institute (RPMI) medium and incubated for 5 days with recombinant mycolactone PKS domains and mycolyltransferase antigen 85A (Ag85A). Blood samples were obtained before and at completion of antibiotic treatment for 8 weeks and again 8 weeks after completion of treatment. Supernatants were assayed for interferon-γ (IFN-γ) and interleukin-5 (IL-5) by enzyme-linked immunosorbent assay. Responses were compared with those of contacts and non-endemic controls. Results: More than 80% of patients and contacts from endemic areas produced IFN-γ in response to all the antigens except acyl carrier protein type 3 (ACP3) to which only 47% of active Buruli ulcer cases and 71% of contacts responded. The highest proportion of responders in cases and contacts was to load module ketosynthase domain (Ksalt) (100%) and enoylreductase (100%). Lower IL-5 responses were induced in a smaller proportion of patients ranging from 54% after ketoreductase type B stimulation to only 21% with ketosynthase type C (KS C). Among endemic area contacts, the, highest proportion was 73% responding to KS C and the lowest was 40% responding to acyltransferase with acetate specificity type 2. Contacts of Buruli ulcer patients produced significantly higher IFN-γ and IL-5 responses compared with those of patients to PKS domain antigens and to mycolyltransferase Ag85A of M. ulcerans. There was low or no response to all the antigens in non-endemic areas controls. IFN-γ and IL-5 responses of patients improved after treatment when compared to baseline results. Discussion: The major response to PKS antigen stimulation was IFN-γ and the strongest responses were observed in healthy contacts of patients living in areas endemic for Buruli ulcer. Patients elicited lower responses than healthy contacts, possibly due to the immunosuppressive effect of mycolactone, but the responses were enhanced after antibiotic treatment. A vaccine made up of the most immunogenic PKS domains combined with the mycolyltransferase Ag85A warrants further investigation

First evidence of Palaeo-Tethyan Upper Triassic calcareous nannofossils in North Dobrogean Orogen (Romania)

This study presents the analysis of Upper Triassic sediments from five locations in North Dobrogea (Romania) and the Black Sea. Microfacies analyses on thin sections from the Frecăţei log reveal a shallowing trend and likely an increase in energy upward into the section. The oldest part of the log is characterised by deposition of mudstones transitioning to wackestones, with an increase of bivalves. Similar wackestones are observed in the Izvoarele and Rândunica logs, i.e. microfacies with abundant bivalves, some foraminifera and echinoderms. The off-shore boreholes 816 and 817 Lebăda Vest (core CM 9 and CM 31) seem to have been deposited in a basinal or distal marine shelf environment indicated by the presence of mudstones with rare bioclasts. In contrast, sample CM 10 from borehole 816 LV is a micritised grainstone suggesting a deposition in a shallower, higher energy environment. Scanning electron microscope observations reveal a moderate diagenetic alteration in all studied samples, mainly due to dissolution. Two calcareous nannofossil species: Prinsiosphaera triassica triassica and Eoconusphaera zlambachensis were commonly observed in sample F of the Frecăţei log, allowing for assignment of the sediments to the Rhaetian age. Two coccoliths were also observed in sample F of Frecăţei log and sample CM 9 of the borehole 816 LV indicating the presence of coccolithophorids within the study region. This discovery constitutes the first confirmed record of well-preserved, determinable Upper Triassic calcareous nannofossils in the Palaeo-Tethys Ocean

Clasificación de humedales en la cuenca del Río Copiapó para la conservación de la fauna vertebrada, según su valor ambiental y la presión antrópica

Memoria para optar al título profesional de Ingeniero en Recursos Naturales RenovablesLos humedales de la cuenca del río Copiapó se encuentran en una situación crítica debido a la intervención y la extracción de agua para actividades humanas. Se realizó una clasificación de 30 humedales en base a su relevancia ambiental para la conservación, la cual se obtuvo a partir de la ponderación del valor ambiental, definido como la combinación de algunos atributos comunitarios de la fauna vertebrada (riqueza de especies, singularidad, especies amenazadas), y de la presión antrópica (una medida de la intervención humana actual y potencial) a partir de cartografías de usos del territorio. Además, se analizaron y compararon tres ecuaciones de valor ambiental propuestas. Los resultados mostraron las dificultades en el levantamiento de información y la importancia de los algoritmos elegidos para la valoración de sitios. Se destaca lo inevitable de establecer criterios subjetivos de priorización o, en su defecto, utilizar objetivos de conservación predeterminados. Por medio de las ecuaciones propuestas se determinó la presencia de tres sitios de alta relevancia ambiental: el Estuario del Río Copiapó (ya se encuentra dentro de un área de protección oficial); Río Manflas (se encuentra próximo a un sitio prioritario para la conservación, que corresponde a una declaración de intenciones por organismos públicos); y Piedra Colgada (se encuentra ubicado en una zona de alta presión antrópica y denota deterioro ambiental). Se recomienda la protección oficial de los dos últimos sitios mencionados y medidas de restauración del cause asociado al sector de Piedra Colgada.The wetlands of the Copiapó River basin are in critical condition as a result of human intervention and water extraction. A total of 30 sites wetlands were classified based on the environmental relevance for conservation, which was obtained from the combination of the environmental value, defined as the combination of some community attributes of the vertebrate fauna (species richness, singularities, threatened species), and the anthropogenic pressure, a measure of the actual and potential human intervention in the territory. Three equations of environmental value are proposed and discussed, which showed the difficulties of data collection and the choice of algorithms, where stands out the inevitability of using subjective criteria or establishing objectives for conservation. Using the three proposed equations, 3 sites were defined as of high environmental relevance: the Estuary of the Copiapó river is already inside an officially protected area; Manflas river is near to a site of priority for the conservation, that corresponds to a statement of purpose for public organisms; Piedra Colgada is in an area of “high” anthropogenic pressure. It is recommended the protection of the last two mentioned sites and restoration measures in the riverbed associated to the Piedra Colgada zone

Defensive-lipid droplets: Cellular organelles designed for antimicrobial immunity

Microbes have developed many strategies to subvert host organisms, which, in turn, evolved several innate immune responses. As major lipid storage organelles of eukary- otes, lipid droplets (LDs) are an attractive source of nutrients for invaders. Intracellular viruses, bacteria, and protozoan parasites induce and physically interact with LDs, and the current view is that they “hijack” LDs to draw on substrates for host colonization. This dogma has been challenged by the recent demonstration that LDs are endowed with a protein-mediated antibiotic activity, which is upregulated in response to danger signals and sepsis. Dependence on host nutrients could be a generic “Achilles’ heel” of intracellular pathogens and LDs a suitable chokepoint harnessed by innate immunity to organize a front-line defense. Here, we will provide a brief overview of the state of the conflict and discuss potential mechanisms driving the formation of the ‘defensive- LDs’ functioning as hubs of innate immunity