A histone acetyltransferase regulates active DNA demethylation in Arabidopsis

Active DNA demethylation is an important part of epigenetic regulation in plants and animals. How active DNA demethylation is regulated and its relationship with histone modification patterns are unclear. Here, we report the discovery of IDM1, a regulator of DNA demethylation in Arabidopsis. IDM1 is required for preventing DNA hypermethylation of highly homologous multicopy genes and other repetitive sequences that are normally targeted for active DNA demethylation by Repressor of Silencing 1 and related 5-methylcytosine DNA glycosylases. IDM1 binds methylated DNA at chromatin sites lacking histone H3K4 di- or trimethylation and acetylates H3 to create a chromatin environment permissible for 5-methylcytosine DNA glycosylases to function. Our study reveals how some genes are indicated by multiple epigenetic marks for active DNA demethylation and protection from silencing.     

Accuracy of pastoralists' memory-based kinship assignment of Ankole cattle: a microsatellite DNA analysis

This study aimed to estimate the level of relatedness within Ankole cattle herds using autosomal microsatellite markers and to assess the accuracy of relationship assignment based on farmers' memory. Eight cattle populations (four from each of two counties in Mbarara district in Uganda) were studied. Cattle in each population shared varying degrees of relatedness (first-, second- and third-degree relatives and unrelated individuals). Only memory-based kinship assignments which farmers knew with some confidence were tested in this experiment. DNA isolated from the blood of a subsample of 304 animals was analysed using 19 microsatellite markers. Average within population relatedness coefficients ranged from 0.010 ± 0.005 (Nshaara) to 0.067 ± 0.004 (Tayebwa). An exclusion probability of 99.9% was observed for both sire-offspring and dam-offspring relationships using the entire panel of 19 markers. Confidence from likelihood tests performed on 292 dyads showed that first-degree relatives were more easily correctly assigned by farmers than second-degree ones (p < 0.01), which were also easier to assign than third-degree relatives (p < 0.01). Accuracy of kinship assignment by the farmers was 91.9% ± 5.0 for dam-offspring dyads, 85.5% ± 3.4 for sire-offspring dyads, 75.6% ± 12.3 for half-sib and 60.0% ± 5.0 for grand dam-grand offspring dyads. Herd size, number of dyads assigned and length of time spent by the herder with their cattle population did not correlate with error in memorizing relationships. However, herd size strongly correlated with number of dyads assigned by the herder (r = 0.967, p < 0.001). Overall, we conclude that memorized records of pastoralists can be used to trace relationships and for pedigree reconstruction within Ankole cattle populations, but with the awareness that herd size constrains the number of kinship assignments remembered by the farmer.     

The effect of two different routes of administration of oxytocin on peripheral plasma prostaglandin F(2α) metabolite levels in early post-partum dairy cows

Various parenteral treatment forms of oxytocin, as often used under praxis circumstances, may act differently on contractility of the uterus during the first days of the puerperium. Various patterns of such induced uterotonic responses may lead to alterations in the emptying characteristics of the uterine lumen, thus influencing, as a late consequence, the process of involution. Therefore, this study was designed to test whether two different parenteral administration forms of oxytocin induce changes in peripheral plasma concentrations of 15-ketodihydro-prostaglandin F(2α) (PGF(2α) metabolite) in early post-partum cows. Between 13 and 15 h after uncomplicated calving, healthy dairy cows without retained foetal membranes were treated with 50 IU oxytocin, either intramuscularly (OT-IM group; n = 15) or intravenously (OT-IV group; n = 16). Saline solution was administered intramuscularly as controls (CON group; n = 15). Jugular blood samples were taken at 10-min intervals from 1 h before to 2 h after treatment. Plasma PGF(2α) metabolite levels were measured by radioimmunoassay. No significant differences in peripheral plasma PGF(2α) metabolite concentrations occurred in the OT-IM and CON groups, but mean values significantly increased in the OT-IV group, peaking at 20 min after treatment and reaching pre-treatment baseline values again at 120 min. Although the source of prostaglandins was not investigated in this study, our results suggest that exogenous oxytocin may enhance secretion of prostaglandins by the uterus during the first day after normal calving. These prostaglandins might contribute, by an endocrine or paracrine route, to the stimulation of myometrial contractility when exogenous oxytocin is given during this early post-partum stage.     

Occurrence and molecular analysis of Campylobacter in wildlife on livestock farms

Wildlife harbor a variety of Campylobacter spp. and may play a significant role in the transmission of Campylobacter to livestock. Although studies have been conducted on wildlife-associated Campylobacter isolates from farms in other countries, there are little data available for livestock farms in the United States. In addition, the critical questions of whether wildlife harbor Campylobacter that is pathogenic to ruminants and/or antibiotic-resistant Campylobacter have yet to be addressed. We captured wild small mammals (n=142) and small birds (n=188) at livestock farms in central Iowa and sampled them for thermophilic Campylobacter during autumn 2009, spring 2010, and autumn 2010. Overall prevalence was 4.79%, with isolates found only in wild birds. Molecular typing revealed four multilocus sequence types (STs), three of which are novel. The remaining ST (ST-806) was found in two house sparrows and is an ST previously associated with ruminant abortion cases. Further analysis of ST-806 wild bird and ruminant abortion isolates by pulsed-field gel electrophoresis, resistance gene location, and antibiotic susceptibility tests indicated that the isolates are nearly identical. This is the first account of isolation of Campylobacter types from wild birds that are known to be pathogenic to ruminants. Furthermore, these same two wild bird isolates are resistant to the antibiotic fluoroquinolone. Our results indicate there is an overall low prevalence of Campylobacter in selected wildlife in Iowa, but suggest that wildlife may play a role in the epidemiology of pathogenic Campylobacter for domestic livestock, and may also serve as a reservoir for antibiotic-resistant Campylobacter.     

Immunohistochemical detection of piscine reovirus (PRV) in hearts of Atlantic salmon coincide with the course of heart and skeletal muscle inflammation (HSMI)

ABSTRACT: Aquaculture is the fastest growing food production sector in the world. However, the increased production has been accompanied by the emergence of infectious diseases. Heart and skeletal muscle inflammation (HSMI) is one example of an emerging disease in farmed Atlantic salmon (Salmo salar L). Since the first recognition as a disease entity in 1999 it has become a widespread and economically important disease in Norway. The disease was recently found to be associated with infection with a novel reovirus, piscine reovirus (PRV). The load of PRV, examined by RT-qPCR, correlated with severity of HSMI in naturally and experimentally infected salmon. The disease is characterized by epi-, endo- and myocarditis, myocardial necrosis, myositis and necrosis of the red skeletal muscle. The aim of this study was to investigate the presence of PRV antigens in heart tissue of Atlantic salmon and monitor the virus distribution in the heart during the disease development. This included target cell specificity, viral load and tissue location during an HSMI outbreak. Rabbit polyclonal antisera were raised against putative PRV capsid proteins μ1C and σ1 and used in immunohistochemical analysis of archived salmon heart tissue from an experimental infection. The results are consistent with the histopathological changes of HSMI and showed a sequential staining pattern with PRV antigens initially present in leukocyte-like cells and subsequently in cardiomyocytes in the heart ventricle. Our results confirm the association between PRV and HSMI, and strengthen the hypothesis of PRV being the causative agent of HSMI. Immunohistochemical detection of PRV antigens will be beneficial for the understanding of the pathogenesis of HSMI as well as for diagnostic purposes.     

Rhipicephalus sanguineus (Ixodida, Ixodidae) as intermediate host of a canine neglected filarial species with dermal microfilariae

The life cycles of filarioids of dogs presenting dermal microfilariae have been little studied. Following the recent retrieval of dermal microfilariae identified as Cercopithifilaria sp. in a dog from Sicily (Italy), this study was designed to assess the role of the brown dog tick Rhipicephalus sanguineus as an intermediate host of this filarial species. An experimental tick infestation was performed on an infected dog using 300 nymphs of R. sanguineus. Engorged nymphs were collected and examined by both microscopic dissection and molecular analysis at five time points (i.e., the same day of tick detachment and 10, 20, 30 and 50 days post-detachment) to detect the presence and developmental stage of filariae in the ticks. A total of 270 engorged nymphs were collected from the dog and developing filarioid larvae detected in 10 (5%) out of 200 ticks dissected. Infective third-stage larvae were observed in 4 (2%) of the all dissected ticks, 30 days post-detachment. Twelve (6.6%) out of 181 samples molecularly tested were positive for Cercopithifilaria sp. This study demonstrates that nymphs of R. sanguineus feeding on a dog naturally infected by Cercopithifilaria sp. can ingest microfilariae, which develop up to the third infective stage thus suggesting that this tick species might act as an intermediate host of this little known canine filarioid.     

Immunoprotective effect of cysteine proteinase fractions from two Haemonchus contortus strains adapted to sheep and goats

A preliminary analysis of the significance of genetic diversity in cysteine proteinase genes has been performed simultaneously in sheep and goats, with regard to the immunological control using these enzymes against haemonchosis. For this purpose, we have studied the cross-immunoprotective effect of cysteine protease-enriched protein fractions (CPFs) in adult worms of two Haemonchus contortus strains from North America and Spain that are adapted to sheep and goats, respectively. Previous genetic analysis of cysteine proteinase genes in both strains has shown that some of loci are polymorphic and these differences are translated into changes in the amino acid sequences. However, our results show that CPFs from H. contortus adult worms have a protective effect against the parasite in both sheep and goats. These results are similar regardless of whether they were obtained from sheep or goat-adapted H. contortus strains, which could be very important in case H. contortus CPFs were commercially used in different countries, as vaccines to prevent the negative effects of this parasite. Interestingly, this experimental inoculation of both species with a heterologous strain of H. contortus contributes to the idea shown in previous studies about how difficult is the interpretation and the comparison of vaccination where strains not adapted to a specific host are used. Therefore, the challenger of using heterologous strains could provide similar results to those observed in immunised animals. This study suggests the possibility of exploring the mechanisms involved in natural protection against non-adapted strains, in order to develop strategies to control haemonchosis.     

Comparative efficacy of flubendazole and a commercially available herbal wormer against natural infections of Ascaridia galli, Heterakis gallinarum and intestinal Capillaria spp. in chickens

The efficacy of a commercially available flubendazole-based product and a commercially available herbal product were compared against three species of helminth parasites of chickens: Ascaridia galli, Heterakis gallinarum and Capillaria spp. A total of 48 naturally infected chickens were used in the study with 16 birds in each of three treatment groups (untreated control; flubendazole; and a herbal product). One bird from each treatment group was necropsied on Day 0 prior to first treatment to confirm the parasite species present in the birds. Treatments were administered as labelled and the 45 remaining birds were necropsied on Day 12 and worm counts performed. Average worm counts in the two treated groups were compared to the untreated controls to calculate efficacy. Flubendazole (Group A) achieved an overall efficacy of 99.4% for the three parasite species. The herbal product (Group B) achieved efficacies ranging from less than zero to 11.6% for the three parasites, with worm counts not significantly different to the untreated controls. At present, commercially available herbal products claiming anthelmintic properties do not require licencing as veterinary medicinal products (Directive 2004/28/EC: see Article 17 and 33-38) and thus are not required to meet specific efficacy thresholds. Products which do not appear to deliver acceptable anthelmintic efficacy, are obviously a concern from many aspects but specifically from an animal welfare perspective.