Characterization of culture supernatant proteins from Brucella abortus and its protection effects against murine brucellosis

In this study, we characterized the secreted proteins of Brucella abortus into the enriched media under the bacterial laboratory growth condition and investigated the pathogenic importance of culture supernatant (CS) proteins to B. abortus infection. CS proteins from stationary phase were concentrated and analyzed using 2D electrophoresis. In MALDI TOF/TOF analysis, more than 27 proteins including CuZn SOD, Dps, Tat, OMPs, Adh, LivF, Tuf, SucC, GroEL and DnaK were identified. Cytotoxic effects of CS proteins were found to increase in a dose-dependent manner in RAW 264.7 cells. Upon B. abortus challenge into phagocytes, however, CS proteins pre-treated cells exhibited lower bacterial uptake and intracellular replication compared to untreated cells. Immunization with CS proteins induced a strong humoral and cell mediated immune responses and exhibited significant higher degree of protection against virulence of B. abortus infection compared to mice immunized with Brucella broth protein (BBP). Taken together, these results indicate that B. abortus secreted a number of soluble immunogenic proteins under laboratory culture condition, which can promote antibody production resulted in enhancing host defense against to subsequently bacterial infection. Moreover, further analysis of CS proteins may help to understand the pathogenic mechanism of B. abortus infection and host–pathogen interaction.     

Effect of topical anesthesia on evaluation of corneal sensitivity and intraocular pressure in rats and dogs

Objective To determine the effect of 0.5% proparacaine in tonometry by evaluating corneal touch threshold (CTT) and intraocular pressure (IOP). Animal studied Nine rats (18 eyes, Sprague–Dawley) and 10 dogs (20 eyes, Beagle) Procedures The IOP and CTT were measured in each eye before and after topical anesthesia with 0.5% proparacaine. The IOP was evaluated using Tonopen for dogs and Tonolab for rats. The corneal sensitivity was evaluated by CTT through a Cochet–Bonnet aesthesiometer. Results The mean IOP was not significantly changed in rats or dogs before and after topical anesthesia. However, after application of proparacaine, CTT was significantly increased in both animal groups compared with that before application of proparacaine. Conclusion From this study, topical anesthesia was found to significantly lower the corneal sensitivity but have little effect on IOP measurements. In ophthalmologic examination, topical anesthesia can be used to reduce corneal sensation without an effect on IOP.     

Protective potential of an attenuated Pasteurella multocida,which expresses only the N-terminal truncated fragment of P. multocida toxin

Pasteurella multocida serogroup D causes progressive atrophic rhinitis in pigs and produces a potent, intracellular, mitogenic toxin known as P. multocida toxin (PMT), which is encoded by the toxA gene. Highly toxic to cells, PMT is a poor antigen and becomes more immunogenic after its native structure has been destroyed. Previously, we found that the N-terminal fragment of PMT (N-PMT) can induce a strong immune response that is protective against wild-type challenge. Here, an attenuated P. multocida mutant expressing only N-PMT was developed and its protective effect was evaluated. The mutant provides protective immune responses against bacterial and toxin challenges, and so is a good live vaccine candidate.     

Ectoparasites are the major causes of various types of skin lesions in small ruminants in Ethiopia

Ectoparasites are the major causes of skin lesions in animals. Clinical, skin scraping examination, and histopathological studies were conducted to identify and characterize skin lesions in small ruminants caused by ectoparasites. Mange mites, lice, sheep keds, and ticks were collected from the skin of affected animals for species identification. Skin biopsies were collected from affected part of the skin and fixed in 10% neutral buffered formalin for histopathology. Of 1,000 sheep and 600 goats examined, 815 (81.50%) sheep and 327 (54.5%) goats were infested with one or more types of ectoparasites. Sarcoptes scabiei var ovis, Demodex ovis, Psoroptes ovis, Bovicola ovis, Melophagus ovinus, and Amblyomma variegatum and other tick species were identified from sheep. S. scabiei var caprae, Demodex caprae, Linognathus stenopsis, and A. variegatum and other tick species were identified from goats. Gross skin lesions or defects observed on the skin include stained and ragged wool, loss of wool/hair, nodules, crusts, lichenification, and fissuring. Microscopic evaluation of H and E stained skin sections revealed lesions in the epidermal layer such as hyperkeratosis, acanthosis, and melanin inconsistency on the basal cells of the epidermis. Follicular keratosis, perifolliculitis, frunculosis, perivasculitis, and aggregates of inflammatory cells (of acute and chronic type) with fibrosis were experiential in the dermal layer of the skin. Most of the skin lesions caused by ectoparasites are overlapping. Thus, ectoparasites control program should be executed to reduce skin lesions as skins are the major export commodity of the country.     

Comparison of the pathogensis of two isolates of <Emphasis Type="Italic">Besnoitia caprae</Emphasis> in inbred BALB/c mice

This study was performed to evaluate the infectivity of bradyzoites of two Besnoitia caprae isolates, BC-1 and BC-2, to inbred BALB/c mice. Each group of inbred BALB/c mice was inoculated intraperitoneally with 1 × 10³, 1 × 10⁴, 1 × 10⁵, 5 × 10⁵ and 1 × 10⁶ of one of the two isolates of B. caprae bradyzoites. The mice were monitored daily for a period of 40 days for survival. After death of each mice, several passages from its peritoneal washing and tissues were analyzed using ribosomal DNA-specific PCR assay. Marked differences in pathogenicity between the isolates were seen. All the inbred BALB/c mice infected with BC-2 survived but all the mice that were administered with 1 × 0⁵, 5 × 10⁵ and 1 × 10⁶ BC-1 bradyzoites were died within 4–9 days post-infection (DPI). Histopathological examination of the tissues of the dead mice revealed hyperemia and necrosis with presence of mononuclear and polymorphonuclear cell infiltration in myocardium, spleen and intestines together with interstitial pneumonia and peritonitis. All inbred BALB/c mice in the 1 × 10³ and 1 × 10⁴ groups of BC-1 inoculated mice survived and they were euthanized after 40 DPI. Chronic inflammation with infiltration of mononuclear cells was evident in myocardium, spleen, alveolar septa of the lungs of most of the examined tissues with hemorrhagic enteritis in the mice infected with 1x10⁶ bradyzoites. The mice infected with different doses of BC-2 were euthanized after 40 DPI and no lesion was seen in histopathological sections of their organs. All peritoneal washings and examined tissues were PCR positive in BC-1 group. This experiment is the first report to show inbred BALB/c mice as a relevant model for B. caprae and demonstrates that this strain of inbred BALB/c mice is a suitable animal model for biological studies and examination of pathogenesis for this species of Besnoitia. The present findings also provide evidence for significant differences between the two isolates of B. caprae.     

The effect of a single intramammary infusion of a biological response modifier in cows at drying off

Biological response modifiers (BRM) are compounds that interact with the immune system to regulate specific aspects of host response. The objective of this study was to describe clinical and morphological changes during involution of bovine mammary gland following a single-dose infusion of a BRM containing lipopolysaccharide and cellular fractions of Escherichia coli incorporated into liposomes. A massive leukocyte response and increased subepithelial stroma infiltration of mononuclear cells, eosinophils and mast cells was observed in BRM-treated quarters compared with untreated controls; however, morphologic parameters assessed at 11 days post infusion were indicative of only slightly accelerated involution compared with untreated controls. In addition, BRM infusion at the end of lactation did not interfere with mammary epithelial cell proliferation and caused only mild systemic effects.     

In situ hybridization for the detection and localization of swine Chlamydia trachomatis

Gnotobiotic piglets were inoculated intralaryngeally with swine Chlamydia trachomatis strain R33 or orally with swine C. trachmatis strain R27. Archived formalin-fixed, paraffin-embedded tissues from piglets euthanatized 4-7 days postinoculation were examined by in situ hybridization for C. trachomatis nucleic acid using a nonradioactive digoxigenin-labeled DNA probes that targeted specific ribosomal RNA or omp1 mRNA molecules of the swine C. trachomatis strains. Positive hybridization signals were detected in bronchial epithelial cells, bronchiolar epithelial cells, pneumocytes, alveolar and interstitial macrophages, and jejunal and ileal enterocytes. Chlamydia-infected cells had a strong signal that was confined to the intracytoplasmic inclusions. Positive hybridization signals were not detected in tissue sections from an uninfected control piglet or in C. psittaci-infected sheep placenta. The morphology of host cells was preserved despite the relatively high temperature required in parts of the incubation procedure. The data indicate that in situ hybridization can be used to detect swine C. trachomatis in formalin-fixed, paraffin-embedded tissue specimens.     

Effects of road transportation on metabolic and immunological responses in Holstein heifers

This study examined the effects of road transportation on metabolic and immunological responses in dairy heifers. Twenty Holstein heifers in early pregnancy were divided into non‐transported (NT; n = 7) and transported (T; n = 13) groups. Blood was collected before transportation (BT), immediately after transportation for 100 km (T1) and 200 km (T2), and 24 h after transportation (AT). The T heifers had higher (P < 0.05) blood cortisol and non‐esterified fatty acid concentrations after T1 and T2 than did NT heifers. By contrast, the T heifers had lower (P < 0.05) serum triglyceride concentrations after T1 and T2 than had the NT heifers. The serum cortisol and triglyceride concentrations returned (P > 0.05) to the BT concentrations at 24 h AT in the T heifers. The granulocyte‐to‐lymphocyte ratio and the percentage of monocytes were higher (P < 0.05) after T2 in the T heifers than in the NT heifers, suggesting that transportation stress increased the numbers of innate immune cells. T heifers had higher (P < 0.01) plasma haptoglobin concentrations than NT heifers 24 h AT. In conclusion, transportation increased cortisol secretion and was correlated with increased metabolic responses and up‐regulation of peripheral innate immune cells in dairy heifers.     

Early exposure to probiotics in a canine model of atopic dermatitis has long-term clinical and immunological effects

Probiotics modulate the immune response and may have protective effects against atopic dermatitis (AD). Clinical trials using dogs with spontaneous disease are limited by confounding factors such as different diets, environments and sensitizations while a more controlled evaluation is possible using experimental models. A validated model of canine AD showed that early exposure to Lactobacillus rhamnosus GG (LGG) significantly decreases allergen-specific IgE and partially prevents AD in the first 6 months of life. This study is a follow-up three years after discontinuation of LGG. Clinical signs were evaluated after allergen challenge with ragweed, timothy, Dermatophagoides farinae. Allergen-specific IgE, IL-10 and TGF-β were measured on the 1st day of challenge, before allergen exposure. Normal dogs were included as controls. Analyses included seven dogs in the non-probiotic and nine in the probiotic litter. For clinical scores, a 2-Group × 9-Time Analysis of Variance showed significant effects of group (p=0.0003, probiotic相似文献