Study of ehrlichiosis in kennel dogs under treatment and prevention during seven months in Dakar (Senegal)

In Dakar kennels where morbidity and mortality attributed to diseases transmitted by ticks were high, we conducted a field study to assess the prevalence of Ehrlichia canis, Anaplasma platys and Babesia spp. infections in two kennels (n = 34 dogs) and to study the impact of tick protection. The first day of the study, the E. canis PCR were positive in 18 dogs (53%). A. platys was found in one dog and all dogs were negative for Babesia spp. After one month of doxycycline treatment, the number of PCR positive dogs decreased significantly to 2 (5.9%). During seven months, all dogs were treated monthly topically with a novel combination (Certifect^®, Merial) delivering at least 6.7 mg fipronil/kg body weight, 8.0 mg amitraz/kg and 6 mg (S)-methoprene/kg. The number of PCR positive dogs remained stable all over the seven months, with 4 dogs being positive at Day 90 and 2 at Day 210. The combination of treatment and monthly prevention had a significant effect in the two kennels. All dogs remained healthy, which was not the case in previous years.     

Survey of Anaplasmataceae bacteria in sheep from Senegal

Purpose

The authors studied the role of bacteria belonging to Anaplasmataceae family as the causes of acute illnesses of sheep in West Africa.

Methods

We examined and sampled 120 febrile sheep in two regions of Senegal for this study. The DNA extracted from these blood samples was tested by PCR using two pairs of primers (groEL-based and 16S rRNA gene-based).

Results

In 52/120 samples, the microscopic examination revealed intraerythrocytic and/or intraphagocytic spherical inclusions. In 48/52 cases, we succeeded in identifying the bacterial agent: in 38 cases, it was Anaplasma ovis; in six cases, it was Ehrlichia ruminantium; in two cases, Anaplasma phagocytophilum; in one case, Anaplasma platys; and in one case, a yet uncultured Anaplasma sp. closely related to A. phagocytophilum.

Conclusions

Our studies demonstrated the great variety of pathogenic bacteria from the Anaplasmataceae family in the blood of clinically ill sheep. A. ovis was identified unexpectedly often. For the first time, A. phagocytophilum was found in sub-Saharan Africa, and its further epidemiology may be now reconsidered. The roles of canine pathogen, A. platys, and yet undescribed Anaplasma sp. “Badiouré” in ovine pathology should be more closely studied.     

Impact of irrigation water quality on soil nitrifying and total bacterial communities

Disturbance induced by two contrasting irrigation regimes (groundwater versus urban wastewater) was evaluated on a sandy agricultural soil through chemical and microbial analyses. Contrary to wastewater, groundwater displayed very high nitrate contents but small amounts of ammonium and organic matter. Despite these strong compositional shifts, soil organic carbon and nitrogen, nitrate and ammonium contents were not significantly different in both types of irrigated plot. Moreover, neither microbial biomass nor its activity, determined as fluorescein diacetate hydrolysis activity, was influenced by irrigation regimes. Bacterial community structure, assessed by denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA fragments, was also weakly impacted as molecular fingerprints shared an overall similarity of 85%. Ammonia-oxidizing bacterial community (AOB) was monitored by DGGE of the functional molecular marker amoA gene (alpha subunit of the ammonia monooxygenase). Surprisingly, no amoA signals were obtained from plots irrigated with groundwater, whereas signal intensities were high in all plots under wastewater. Among the last, compositional shifts of the AOB community were weak. Overall, impact of irrigation water quality on soil chemistry could not be evidenced, whereas effects were low on the total bacterial compartment but marked on the AOB community.     

Changes in the diversity and geographic distribution of cultivated millet (Pennisetum glaucum (L.) R. Br.) and sorghum (Sorghum bicolor (L.) Moench) varieties in Niger between 1976 and 2003

Changes in the diversity of landraces in centres of diversity of cultivated plants need to be assessed in order to monitor and conserve agrobioversity—a key-element of sustainable agriculture. This notably applies in tropical areas where factors such as increased populations, climate change and shifts in cropping systems are hypothesized to cause varietal erosion. To assess varietal erosion of staple crops in a country subjected to various anthropogenic and natural environmental changes, we carried out a study based on a comparison of the diversity of pearl millet and sorghum varieties collected in 79 villages spanning the entire cereal-growing zone of Niger over a 26 year period (1976–2003). For these two crops, the number, name and type of varieties according to important traits for farmers were considered at different spatial scales (country, region, village) at the two collection dates. The results confirmed the high diversity of millet and sorghum varieties in Niger. No erosion of varietal diversity was noted on a national scale during the period covered. Some changes were observed but were limited to the geographical distribution of certain varieties. This highlights that farmers’ management can preserve the diversity of millet and sorghum varieties in Niger despite recurrent and severe drought periods and major social changes. It also indicates that rainfed cereal cropping systems in Niger should remain to be based on millet and sorghum, while reinforcing farmers’ seed systems.     

A novel Gateway®-compatible binary vector allows direct selection of recombinant clones in Agrobacterium tumefaciens

Background

In vivo detection of protein-bound genomic regions can be achieved by combining chromatin-immunoprecipitation with next-generation sequencing technology (ChIP-seq). The large amount of sequence data produced by this method needs to be analyzed in a statistically proper and computationally efficient manner. The generation of high copy numbers of DNA fragments as an artifact of the PCR step in ChIP-seq is an important source of bias of this methodology.

Results

We present here an R package for the statistical analysis of ChIP-seq experiments. Taking the average size of DNA fragments subjected to sequencing into account, the software calculates single-nucleotide read-enrichment values. After normalization, sample and control are compared using a test based on the ratio test or the Poisson distribution. Test statistic thresholds to control the false discovery rate are obtained through random permutations. Computational efficiency is achieved by implementing the most time-consuming functions in C++ and integrating these in the R package. An analysis of simulated and experimental ChIP-seq data is presented to demonstrate the robustness of our method against PCR-artefacts and its adequate control of the error rate.

Conclusions

The software ChIP-seq Analysis in R (CSAR) enables fast and accurate detection of protein-bound genomic regions through the analysis of ChIP-seq experiments. Compared to existing methods, we found that our package shows greater robustness against PCR-artefacts and better control of the error rate.     

Effects of nitric oxide and tumor necrosis factor-alpha on production of prostaglandin F2alpha and E2 in bovine endometrial cells

The purpose of this study was to determine whether nitric oxide (NO) mediates tumor necrosis factor (TNF)alpha influence on the bovine endometrium. TNFalpha influence on the bovine endometrium is limited to the stromal cells. Therefore, it was interesting to find out whether NO production by the stromal cells, stimulated by TNFalpha might influence the endometrial epithelium. Moreover, we investigated the intracellular mechanisms of TNFalpha- and NO-regulated prostaglandin (PG) F(2alpha) and PGE(2) synthesis. Epithelial and stromal cells from the bovine endometrium (Days 2-5 of the oestrous cycle) were separated by means of enzymatic dispersion and cultured for 6-7 days in 48-well plates. The confluent endometrial cells were exposed to a NO donor (S-NAP; 1-1000 microM) for 24 h. S-NAP strongly stimulated PGE(2) production in both bovine endometrial cell types (P<0.001). The effect of SNAP on PGF(2alpha) production was limited only to the stromal cells (P<0.05). To study the intracellular mechanisms of TNFalpha and NO action, stromal cells were incubated for 24 h with TNFalpha or S-NAP and with NO synthase (NOS) inhibitor (L-NAME; 10 microM) or an inhibitor of phosphodiesterase (IBMX; 10 microM). When the cells were exposed to TNFalpha in combination with NOS inhibitor (L-NAME), TNFalpha-stimulated PGs production was reduced (P<0.05). The inhibition of enzymatic degradation of cGMP by IBMX augmented the actions of S-NAP and TNFalpha on PGs production (P<0.05). The overall results suggest that TNFalpha augments PGs production by bovine endometrial stromal cells partially via induction of NOS with subsequent stimulation of NO-cGMP formation. NO also stimulates PGE(2) production in epithelial cells.     

Contextualized re-calculation of enteric methane emission factors for small ruminants in sub-humid Western Africa is far lower than previous estimates

Tropical Animal Health and Production - Given the projected growth of methane emission by ruminants in developing countries, there is a clear need for reliable estimates of their contribution to...     

High selfing rate inferred for white fonio [<Emphasis Type="Italic">Digitaria exilis</Emphasis> (Kippist.) Stapf] reproductive system opens up opportunities for breeding programs

In a context of the global major changes, it is mandatory to enlarge the range of crops supporting food security and pay great attention to neglected and underutilized species. However, basic knowledge of the biology of many neglected and underutilized species is still lacking to increase their yields. In this study, the mating system of white fonio [Digitaria exilis (Kippist.) Stapf], a West African minor and promising cereal, is assessed. Progenies arrays from both homozygous and heterozygous mothers were genotyped with microsatellites markers. The rate of genotyping errors in the experiments was assessed and a likelihood framework was used to determine the probability of different mating systems: outcrossing, self-fertilization and apomixis. The results suggested that white fonio has a highly selfing reproductive system with a possible outcrossing rate of 1.7%. Understanding the reproduction system of white fonio opens up opportunities for more effective breeding programs and a wider use of this cereal for food security improvement.     

Photodegradation of Sulfamethoxazole Applying UV- and VUV-Based Processes

The efficiency of UV- and VUV-based processes (UV, VUV, UV/H₂O₂, and VUV/H₂O₂) for removal of sulfamethoxazole (SMX) in Milli-Q water and sewage treatment plant (STP) effluent was investigated at 20??C. The investigated factors included initial pH, variety of inorganic anions (NO ₃ ^? and HCO ₃ ^? ), and humic acid (HA). The results showed that the degradation of SMX in Milli-Q water at both two pH (5.5 and 7.0) followed the order of VUV/H₂O₂ > VUV > UV/H₂O₂ > UV. All the experimental data well fitted the pseudo-first order kinetic model and the rate constant (k) and half-life time (t _1/2) were determined accordingly. Indirect oxidation of SMX by generated ^?OH was the main degradation mechanism in UV/H₂O₂ and VUV/H₂O₂, while direct photolysis predominated in UV processes. The quenching tests showed that some other reactive species along with ^?OH radicals were responsible to the SMX degradation under VUV process. The addition of 20?mg?L^?1 HA significantly inhibited SMX degradation, whereas, the inhibitive effects of NO ₃ ^? and HCO ₃ ^? (0.1?mol?L^?1) were observed as well in all processes except in UV irradiation for NO ₃ ^? . The removal rate decreased 1.7?C3.6 times when applying these processes to STP effluent due to the complex constituents, suggesting that from the application point of view the constituents of these complexes in real STP effluent should be considered carefully prior to the use of UV-based processes for SMX degradation.