Experimental infection with a low virulence isolate of Neospora caninum at 70 days gestation in cattle did not result in foetopathy

The Nc-Spain 1H isolate of Neospora caninum, which was newly obtained from the brain of a congenitally asymptomatic infected calf, demonstrated a reduced in vitro tachyzoite yield and viability rate, as well as low virulence in mouse models. The objective of the present study was to determine the ability of this isolate to induce foetal death in a pregnant bovine model. For this purpose, 13 naïve pregnant heifers were divided into three groups and were experimentally challenged with either 10⁷ tachyzoites of Nc-1 (group 1, n = 5), Nc-Spain 1H (group 2, n = 5) isolates or phosphate-buffered saline (group 3, n = 3) intravenously at 70 days of gestation. After inoculation, pregnancy was monitored and dams were sacrificed when foetal death was detected. The remaining animals were slaughtered at 45 days post-infection. Maternal and foetal samples were collected for examination by histology and parasite DNA detection. Parasitaemia, specific anti-N. caninum IgG and interferon γ responses were also studied. At 3–4 weeks after infection, foetal death was detected in 3 out of 5 Nc-1-infected dams. However, no evidence of foetal death was observed in either Nc-Spain 1H-infected or control groups during the period studied. The most severe histopathological lesions were observed in the placenta and foetal organs from Nc-1-infected cattle that exhibited foetal death. It was in these animals that N. caninum DNA was more frequently detected. Parasitaemia was observed in all Nc-1-infected dams and in only 3 out of 5 Nc-Spain 1H-infected animals. The magnitude of the immune response was significantly higher in the Nc-1-inoculated group than in the group inoculated with the Nc-Spain 1H isolate. These data reveal the reduced virulence of the Nc-Spain 1H isolate in cattle.     

Effect of neutral detergent soluble fibre on digestion, intestinal microbiota and performance in twenty five day old weaned rabbits

The effect of neutral detergent soluble fibre (NDSF) level on digestibility, fermentation traits, intestinal microbiota and performance was studied in weaned rabbits. A control diet (DA) containing 103 g NDSF/kg DM included dehydrated alfalfa as the main source of fibre. Another diet (B-AP) was formulated by replacing half of the dehydrated alfalfa with a mixture of beet and apple pulp resulting in 131 g NDSF/kg DM. A third diet (OH) was obtained by substituting half of the dehydrated alfalfa with a mix of oat hulls and a soybean protein concentrate and contained 79 g NDSF/kg DM. All diets contained similar levels of total fibre (NDSF + neutral detergent fibre), starch and protein (446, 208, and 199 g/kg DM, respectively). Forty-two rabbits (14/diet) weaned at 25 days were used to determine faecal digestibility from 32 to 35 days of age. This group, plus another nine rabbits/diet (23/diet), were used to determine weight of stomach and caecum and their contents, caecal fermentation traits and similarity rate (SR) of intestinal microbiota. Another 105 and 245 weaned rabbits were used to determine growth traits and mortality, respectively. From 25 to 39 days of age, rabbits were fed the experimental diets and from 39 to 60 days they were fed a commercial diet, including robenidine hydrochloride in all diets. Drinking water was supplemented with apramicine sulfate and tylosine tartrate throughout the experimental period. Faecal and energy digestibility increased linearly by 8% and NDF digestibility by 43% between extreme diets with NDSF inclusion (P < 0.001). Weight of total gastrointestinal tract decreased linearly and quadratically with NDSF reduction (P = 0.008 and P = 0.089, respectively). Stomach pH decreased linearly with increasing levels of NDSF (P ≤ 0.041). Weight of caecal contents increased linearly between animals fed OH and B-AP diets (P < 0.001). Level of inclusion of NDSF had no effect (P ≥ 0.12) on pH, VFA concentration and VFA molar proportions in caecal contents. Treatments appeared to influence the SR of caecal microbiota but a lesser effect was observed on ileal microbiota. Post weaning feed efficiency (25–39 days) increased linearly (P < 0.001) with NDSF inclusion by 10% between extreme diets, and by 3% in the whole fattening period (P = 0.027). Average feed intake during the post weaning (25–39 days) and the whole fattening period increased with NDSF reduction (P ≤ 0.079). No effect of NDSF was detected on average daily gain (P ≥ 0.15). Mortality decreased linearly with increasing levels of NDSF in the post weaning and in the whole fattening period (P = 0.086 and 0.016, respectively).     

Evaluation of the effect of two dose rates of cyclosporine on the severity of perianal fistulae lesions and associated clinical signs in dogs

OBJECTIVE: To investigate the effect of cyclosporine (2 or 5 mg/kg every 24 hours) on perianal fistulae (PAF) lesions. STUDY DESIGN: Blinded randomized, prospective trial. ANIMALS: Dogs (n = 20) with perianal fistulae. METHODS: Dogs were randomly assigned to administration of either 2 mg/kg (n = 10) or 5 mg/kg (n=10) of cyclosporine orally every 24 hours for 8 weeks. Lesion surface area was measured, lesion severity was graded using a visual analog scale, and the presence and severity of clinical signs recorded every 2 weeks. RESULTS: Lesion variables were significantly reduced in both groups after 8 weeks and owners also reported a reduction in clinical sign severity. The 5 mg/kg dose rate significantly accelerated lesion resolution compared with 2 mg/kg. In the 2 mg/kg group, 20% of dogs had complete resolution of clinical signs and 10% had resolution of lesions. In the 5 mg/kg group, 40% of dogs had complete resolution of clinical signs and 60% had resolution of lesions. CONCLUSIONS: A dose rate of 5 mg/kg every 24 hours was more effective at reducing the surface area and severity of PAF lesions than 2 mg/kg every 24 hours but less effective at resolving PAF lesions than previous studies using dose rates > or =5 mg/kg every 12 hours. CLINICAL RELEVANCE: Cyclosporine at 5 mg/kg every 24 hours may be useful for the palliation of PAF lesions.     

Cytokine expression in porcine lungs experimentally infected with Mycoplasma hyopneumoniae

To gain further insight into the pathogenesis of porcine enzootic pneumonia (PEP), cytokine expression in different pulmonary compartments was examined. Mycoplasma hyopneumoniae (Mh) and proinflammatory and immunoregulatory cytokines (IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10 and TNF-alpha) were detected by immunohistochemical methods in porcine lungs experimentally infected with Mh. Ten pigs were inoculated intranasally with Mh and killed in pairs weekly from 1- to 5-week post-inoculation (wpi). Three Mh-free pigs were taken as controls. Mh-antigen was shown in paraffin-wax-embedded tissues by immunohistochemistry in the luminal surface of bronchial and bronchiolar epithelial cells of all Mh-infected pigs. Significant increase in cytokine expression was detected on snap-frozen tissues from the bronchoalveolar exudate of the airways, mononuclear cells of the alveolar septa and macrophages and lymphocytes of the peribronchial and peribronchiolar lymphoid tissue, from 1 wpi onwards, compared to expression in non-pneumonic lungs. The main cytokines in the BALT of Mh-infected animals that showed an increase were IL-2, IL-4, IL-8, IL-10 and TNF-alpha. In the alveolar septa and bronchoalveolar exudate IL-1 (alpha and beta), IL-2, IL-4, IL-8 and IL-10 expression also increased in infected animals.     

Apoptotic and free radical scavenging properties of the methanolic extract of Gentianella alborosea

Gentianella alborosea ("Hercampure") is a Peruvian species used in folk medicine for the treatment of a variety of health disorders. We tested the free radical scavenging (DPPH) and induction of apoptosis on a human uterus tumor cell line (HeLa) by its methanolic extract. The results showed a noticeable radical scavenging activity and a dose-dependent apoptotic effect.     

The recombinant rabbit hemorrhagic disease virus VP60 protein obtained from Pichia pastoris induces a strong humoral and cell-mediated immune response following intranasal immunization in mice

Rabbit hemorrhagic disease (RHD) is a contagious and highly lethal viral disease of rabbits that spreads rapidly and infects animals by nasal, conjunctival and oral routes. Therefore, this experiment was undertaken to study the immune response generated after intranasal (i.n.) vaccination with the recombinant VP60 capsid protein from rabbit hemorrhagic disease virus (RHDV) expressed at high levels in Pichia pastoris. Groups of BALB/c mice were immunized with three doses of purified VP60 protein (Group 1), VP60 formulated within the cell debris fraction of the transformed yeast (Group 2) and placebo (Group 3) by intranasal route. Mice were also intramuscularly injected with purified VP60 protein (Group 4). A rapid antibody response specific against rabbit hemorrhagic disease virus was observed in all the experimental groups, except in Group 3, as detected by ELISA. The highest titers were found 60 days after the first immunization. Mice from Group 1 showed the highest IgG response (p<0.05) and the most balanced profile of IgG1, IgG2a and IgG2b subclasses. IgA titers specific to the virus were found only in animals from this group, which also developed the highest specific lymphocyte proliferative response. Interferon-gamma (IFN-gamma) and interleukin-12 (IL-12) gene expression was also detected after an ex vivo-specific stimulation of mice from Groups 1 and 4. These data demonstrated the capacity of VP60 protein expressed in P. pastoris to elicit a potent humoral and cell-mediated immune response following an intranasal immunization scheme.     

Affinity purification of angiotensin converting enzyme inhibitory peptides using immobilized ACE

A lung extract rich in angiotensin converting enzyme (ACE) and pure ACE were immobilized by reaction with the activated support 4 BCL glyoxyl-agarose. These immobilized ACE derivatives were used for purification of ACE inhibitory peptides by affinity chromatography. The immobilized lung extract was used to purify inhibitory peptides from sunflower and rapeseed protein hydrolysates that had been obtained by treatment of protein isolates with alcalase. The ACE binding peptides that were retained by the derivatives were specifically released by treatment with the ACE inhibitor captopril and further purified by reverse-phase C18 HPLC chromatography. Inhibitory peptides with IC50 50 and 150 times lower than those of the original sunflower and rapeseed hydrolysates, respectively, were obtained. The derivative prepared using pure ACE was used for purification of ACE inhibitory peptides from the same type of sunflower protein hydrolysate. ACE binding peptides were released from the ACE-agarose derivatives by treatment with 1 M NaCl and had an IC50 a little higher than those obtained using immobilized extract and elution with captopril. Affinity chromatography facilitated the purification of ACE inhibitory peptides and potentially other bioactive peptides present in food proteins.     

Allelopathy--a natural alternative for weed control

Allelopathy studies the interactions among plants, fungi, algae and bacteria with the organisms living in a certain ecosystem, interactions that are mediated by the secondary metabolites produced and exuded into the environment. Consequently, allelopathy is a multidisciplinary science where ecologists, chemists, soil scientists, agronomists, biologists, plant physiologists and molecular biologists offer their skills to give an overall view of the complex interactions occurring in a certain ecosystem. As a result of these studies, applications in weed and pest management are expected in such different fields as development of new agrochemicals, cultural methods, developing of allelopathic crops with increased weed resistance, etc. The present paper will focus on the chemical aspects of allelopathy, pointing out the most recent advances in the chemicals disclosed, their mode of action and their fate in the ecosystem. Also, attention will be paid to achievements in genomics and proteomics, two emerging fields in allelopathy. Rather than being exhaustive, this paper is intended to reflect a critical vision of the current state of allelopathy and to point to future lines of research where in the authors' opinion the main advances and applications could and should be expected.