Leukocyte endothelial cell interactions in pig to human organ xenograft rejection

In cases where antibody- and complement-mediated hyperacute rejection (HAR) of vascularized organ xenografts has been prevented, acute vascular rejection (AVR) and acute T cell-mediated rejection (ACR) cause graft destruction. Infiltration of leukocytes (innate and graft-primed T cells) into the graft execute the latter two rejection modalities. The leukocyte extravasation process, which is a prerequisite for graft infiltration, is governed by adhesion molecules, including the selectin, integrin and immunoglobulin protein families, and the chemokine protein family. The compatibility between porcine endothelial cell and human leukocyte adhesion molecules was investigated in dynamic adhesion and static transendothelial migration assays. The effect of human anti-pig antibodies on human leukocyte adhesion to, and transendothelial migration across, porcine endothelium was assessed under dynamic and static conditions, respectively. In contrast to previously published results, no difference in the ability of neutrophils to adhere to pig and human endothelium was observed. Furthermore, no evident quantitative or qualitative differences in the capacity of human and porcine endothelium to support transendothelial migration of human leukocytes (T, B and natural killer (NK) cells, monocytes, and neutrophils) could be detected. The presence of human anti-pig antibodies (Abs) modulated the migration of leukocytes across porcine endothelium, as well as neutrophil adhesion to porcine endothelium under conditions of flow. Antibodies specific for pig endothelial adhesion molecules can potentially be used as species (graft)-specific immunosuppressive reagents in order to prevent cellular organ xenograft rejection.     

Astrovirus as a possible cause of congenital tremor type AII in piglets?

Background

Congenital tremor is associated with demyelination of the brain and spinal cord and is clinically noted as outbreaks of trembling and shaking in newborn piglets during a limited time-period. Six forms of the disease have been described, where form AII may be caused by an, as yet, unidentified viral infection. This study aimed to investigate the presence of astrovirus and circovirus by sequencing and polymerase chain reaction (PCR) analysis and by relating the findings to the occurrence of disease and lesions in the brain, in 4–6 days-old piglets obtained from a clinical outbreak of congenital tremor.

Results

In piglets with congenital tremor, there were mild to moderate vacuolar changes of the white matter in the cerebrum, brain stem and cerebellum. In healthy piglets, less conspicuous vacuolar changes were detected. One healthy and one diseased piglet were positive for porcine circovirus type 2. The nested pan-PCR showed the presence of astrovirus in at least one brain region in all piglets and by sequencing, two different porcine astrovirus lineages were identified.

Conclusions

The results do not support previous studies identifying porcine circovirus type 2 as the cause of congenital tremor. The demonstration of astrovirus in the brain of piglets suffering from congenital tremor is interesting. However, astrovirus was demonstrated in both healthy and diseased individuals and therefore, further studies are warranted to determine the possible involvement of astrovirus in the pathogenesis of congenital tremor in pigs.     

A wide diversity of zoonotic intestinal parasites infects urban and rural dogs in Neuquén,Patagonia, Argentina

The presence of parasites was investigated by the examination of 1944 dog faecal samples collected from urban (n = 646) and rural (n = 1298) areas of the province of Neuquén, Patagonia, Argentina. Parasitic agents (PA) were found in 37.86% of samples. A total of 15 different PA were detected, including Toxocara canis (16.35%), Taenia spp./Echinococcus spp. (12.65%), Trichurisvulpis (6.06%), Giardia spp. (1.29%), Toxascaris leonina (0.56%), Ancylostomacaninum (0.41%), Dipylidium caninum (0.31%), Diphyllobothrium spp. (0.10%), among others. Several of these PA are recognized as zoonotic agents. Therefore, the results of this investigation revealed that local population is exposed to a broad spectrum of zoonotic parasites by means of environmental contamination with dog faeces. Prevalence of PA was slightly higher in rural (40.06%) than in urban (33.44%) locations. Distribution of groups of PA (cestodes, nematodes, and protozoa) showed statistical differences between both habitats. Prevalence of cestodes (18.18%) and protozoa (11.86%) was significantly higher in the rural environment than in urban areas and nematodes (29.10%) were more frequent in urban locations. Infection of dogs with Linguatula serrata and Cryptosporidium sp. was demonstrated for the first time in Neuquén. Rural dogs of the study area are under hydatic disease control program, which includes treatment with praziquantel every 6 weeks; thus, the finding of high level of cestode infection in these areas is of great relevance. The epidemiology of zoonotic parasitic infections in urban and rural dogs showed different patterns and, in consequence, different control measurements should be applied in each location.     

Seroepidemiology of beef and dairy herds and fetal study of Neospora caninum in Argentina

The purpose of the present work was to study the epidemiology of Neospora caninum in beef and dairy herds in the Humid Pampas of Argentina. The seroprevalence of N. caninum was evaluated in 2414 serum samples of cows from beef and dairy farms. An indirect fluorescent antibody test (IFAT) was used to determine specific antibodies. The sera was screened at a dilution >or=1:200 and >or=1:600 in cows with reproductive disease antecedents and without them, respectively. Cows without history of reproductive diseases from nine beef and fifteen dairy farms were grouped according to the percentage (> or or 相似文献   

Effect of age and abomasal puncture on peritoneal fluid, hematology, and serum biochemical analyses in young calves

The goals of this study were to evaluate techniques for collection of peritoneal fluid from calves, establish reference ranges for fibrinogen in peritoneal fluid during the 1st month of life, and determine if abomasal puncture would alter peritoneal fluid or hematologic variables. Twenty-two healthy Holstein calves underwent 3 peritoneal fluid collections on day 1, day 15, and day 30 of age. Fibrinogen concentration in peritoneal fluid was 0.20 g/dL and 0.10 g/dL (P < .05) for day 1 and day 30, respectively, and 0.10 at day 15 (P > .05) for calves without abomasal puncture. Plasma fibrinogen concentration was 0.60 g/dL and 0.70 g/ dL (P < .05) for days 15 and 30, respectively, in calves without abomasal puncture. There were no significant differences (P < or = .05) in peritoneal fluid and peripheral blood total protein and fibrinogen concentrations, specific gravity, total and differential cell count, or erythrocyte counts between calves with or without abomasal puncture. We concluded that the reference ranges established for fibrinogen and total protein concentration are important for accurate evaluation of peritoneal fluid in calves for further comparison with similar-aged animals with gastrointestinal-tract or abdominal-cavity disease. Additionally, accidental abomasal puncture does not alter values of fibrinogen, total protein, and nucleated cell count in peritoneal fluid and does not cause apparent clinical abnormalities.     

Resistance gene analogue isolation and RGA-based marker development for identifying downy mildew resistance in radish (Raphanus sativus L.)

Resistance Gene Analogs (RGAs)-based molecular markers can significantly enhance the breeding efficiency for disease resistance in various crops. However, RGAs isolation and RGA-based marker development have not been conducted in radish. In this study, two prevalent approaches, PCR amplification with degenerate primers and data-mining of radish EST databases, were used to isolate radish resistance gene candidate sequences. A total of 26 RsRGAs with high homology to known R-genes or RGAs were obtained by PCR amplification. Meanwhile, 257 R-gene-like unigenes/ESTs were identified using data-mining method. In total, 115 out of 124 designed RGA-specific primer pairs can successfully amplified the target bands. To explore the RGA genetic variability, 32 radish accessions were genotyped and 269 RGA loci were successfully identified. It was found that 44 RGA primers only generated monomorphic band and the remaining 71 RGA primers generated 225 RGA polymorphic bands among the 32 radish accessions. Based on RGA marker analysis, 32 radish accessions were clustered into four main groups at the similarity index of 0.68, which was in a high accordance with disease index from a downy mildew evaluation. This study might be the first report on candidate R-genes identification and RGA-based markers development in radish. These findings will facilitate the disease resistance identification and speed up the genetic improvement of DM resistances in radish breeding programs.     

Flow cytometry: a quick method to determine ploidy levels in honeybush (<Emphasis Type="Italic">Cyclopia</Emphasis> spp.)

Cyclopia (honeybush) species are widely-used in the production of a South African herbal tea and are endemic to the fynbos region of the Western and Eastern Cape Provinces. Honeybush is still one of the orphan agriculture crops and recent breeding efforts by researchers are hampered by the lack of basic genetic information e.g. basic chromosome numbers and ploidy levels. This study determined nuclear DNA content and ploidy level of various genotypes of three Cyclopia species using flow cytometry and cytological counting of chromosomes. Nuclei analysis of young leaves of C. genistoides, C. longifolia and C. subternata were done using a flow cytometer, while root tip squashes were carried out in order to correlate flow cytometry results. Flow cytometry analysis indicated differences in the nuclear DNA content among and within species whilst the DNA ploidy level only differed among species. Cyclopia genistoides had a higher DNA ploidy level (≥?10C) and DNA content (10.63 pg) than C. longifolia (6.09 pg) and C. subternata (5.99 pg), with no differences observed between the ploidy level of the latter two species (6C). The inferred ploidy level from nuclear DNA content by flow cytometry was consistent in all 30 genotypes of C. longifolia, and 24 of the 25 C. subternata and in only four of the 15 C. genistoides studied genotypes. These findings are important in breeding new cultivars with desired horticultural traits, thus improving the commercial characteristics for the sustainable production of honeybush.