Streptococcus equi but not Streptococcus zooepidemicus produces potent mitogenic responses from equine peripheral blood mononuclear cells

Streptococcus equi causes equine strangles. The acute disease has many of the hallmarks of an acute response including high fever, elevated plasma fibrinogen and neutrophilia, affects known to be mediated by proinflammatory cytokines. The objective of this study was to screen-culture supernatants from equine clinical isolates of S. equi and S. zooepidemicus for stimulation of mitogenic responses by horse peripheral blood mononuclear cells. Mitogenicity comparable to that of concanavalin A was detected in culture supernatants of S. equi strains but not in those of S. zooepidemicus. Mitogenicity was neutralised by Proteinase K and a post-strangles convalescent serum, and evidence for the presence of both thermo-resistant and thermo-labile mitogenic factors was obtained. Release of proteinaceous immunogenic mitogens in combination with the antiphagocytic protein SeM unique to S. equi may therefore contribute to some of the severe clinical manifestations of acute strangles in the horse.     

Light and scanning electron microscopic studies of the nasal turbinates of the horse

The nasal turbinates of 5 young horses were studied by light and scanning electron-microscopy. Stratified cuboidal epithelium lined the rostral part of the dorsal and ventral nasal turbinates of the vestibular region. The polyangular microvillus cells of this region were separated by linear depressions. The mid and caudal parts of the dorsal and ventral nasal turbinates and the rostral part of the ethmoturbinates were lined by pseudostratified columnar ciliated respiratory epithelium. Numerous cilia with dilated blebs on the ciliated cells concealed adjacent non-ciliated supporting cells and goblet cells. The olfactory zone consisting of the olfactory vesicle and a dense network of olfactory cilia localized to the caudal part of the ethmoturbinates. The three regions were delineated from each other by transitional zones.     

Antifungal and defense elicitor activities of pyrazines identified in endophytic Pseudomonas putida BP25 against fungal blast incited by Magnaporthe oryzae in rice

Journal of Plant Diseases and Protection - Black pepper-associated endophytic Pseudomonas putida BP25 displayed volatile-mediated antagonism against rice blast fungus Magnaporthe oryzae 1637. The...     

The mucosal humoral immune response of the horse to infective challenge and vaccination with equine herpesvirus-1 antigens.

Equine herpesvirus-1 (EHV-1) remains a frequent cause of upper respiratory tract infection and abortion in horses worldwide. However, little is known about the local antibody response elicited in the upper airways of horses following exposure to EHV-1. This study analysed the mucosal humoral immune response of weanling foals following experimental infection with virulent EHV-1, or vaccination with either of 2 commercial vaccines. Twenty weanlings were assigned to 5 groups and were inoculated with, or vaccinated against, EHV-1 following different regimens. Finally, all weanlings were simultaneously challenged intranasally with virulent EHV-1 Army 183 (A183). Nasal wash and serum samples were collected at regular intervals until 13 weeks after final challenge. Nasal washes were assayed for EHV-1-specific equine IgGa, IgGb, IgG(T), IgA, IgM and total virus-specific antibody using an indirect, quantitative ELISA. Total serum antibody responses were also monitored, and clinical signs of EHV-disease were recorded for each individual. Virus-specific IgA dominated the mucosal antibody response elicited in weanlings inoculated with A183, being detectable at up to 3.1 microg/mg total IgA 13 weeks after challenge. Neither inactivated EHV-1 administered i.m., nor attenuated EHV-1 administered intranasally induced detectable mucosal antibodies. EHV-1-specific mucosal antibodies impeded EHV-1 plaque formation in vitro. Such virus-neutralising antibody probably contributes to a reduction of shedding of EHV-1 from the respiratory tract of virus-infected horses.     

M cells and associated lymphoid tissue of the equine nasopharyngeal tonsil

The aim of this study was to characterise the morphological and histochemical features of equine nasopharyngeal tonsillar tissue. Nasal and oropharyngeal tonsillar tissue has been described as the gatekeeper to mucosal immunity because of its strategic location at the entrance to the respiratory and alimentary tracts. A combination of light, scanning and transmission electron microscopy has revealed the presence of follicle-associated epithelium (FAE) overlying lymphoid tissue of the equine nasopharyngeal tonsil caudal to the pharyngeal opening of the guttural pouch. Membranous microvillus (M) cells were identified in the FAE on the basis of short microvilli, an intimate association with lymphocytes, cytoplasmic vimentin filaments and epitopes on the apical surface reactive with lectin GS I-B4 specific for alpha-linked galactose. CD4-positive lymphocytes were scattered throughout the lamina propria mucosae as well as forming dense aggregates in the subepithelial part. The central follicular area was heavily populated with B lymphocytes and the dome and parafollicular areas contained both CD4- and CD8-positive lymphocytes. CD8-positive lymphocytes were also present in the epithelium and, together with B lymphocytes, in small numbers in the lamina propria mucosae. These observations indicate that the nasopharyngeal tonsil is potentially an important mucosal immune induction site in the horse and an appropriate target for intranasally administered vaccines.     

Association of Streptococcus equi with equine monocytes

Streptococcus equi (Se), the cause of equine strangles, is highly resistant to phagocytosis by neutrophils and is usually classified as an extracellular pathogen. Large numbers of the organism in tonsillar tissues during the acute phase of the disease are completely eliminated during convalescence by mechanisms not yet understood. In this study we demonstrate in an opsono-bactericidal assay and by cytometry and confocal microscopy that Se is interiorized and killed by equine blood monocytes. This finding supports the hypotheses that adaptive immune clearance is mediated by tonsillar macrophages and that macrophages monocytes could serve as a vehicle for transport from the tonsil to local lymph nodes.     

Genomic analysis of local isolate of Mycobacterium avium subspecies paratuberculosis

Mycobacterium avium subspecies paratuberculosis (MAP) causes Johne's disease (JD or paratuberculosis) in animals and has also been implicated in Crohn's disease of humans. It has been shown that MAP is endemic in animal population of India. Understanding of heterogeneity among MAP strains is important both for diagnosis and design control measures. Genotyping and epidemiological investigations revealed that MAP 'Bison type' was the predominant strain infecting domestic ruminant population in India. MAP 'Bison type' has also been reported from USA. A number of comparative genomics studies have been conducted to understand 'Cattle type' and 'Sheep type' strains. However, present study was the first attempt to characterize MAP 'Bison type' S5 using different markers including IS900, ISMAP02, IS1311, LSPs and SSRs. Study showed that MAP S5 is similar to MAP K10 in terms of number of IS900, IS1311 and ISMAP02 elements. There was high sequence similarity for IS900 and ISMAP02 between MAP K10 and MAP S5. However, this study also reported genetic differences between two strains. In some IS1311 loci, TG gap at 64th and 65th position was observed in MAP S5. Further sequencing of few more MAP isolates confirmed that this gap was specific to indigenous MAP 'Bison type' and can be further used as molecular signature. ISMAP02 locus 1 was observed at polymorphic position in MAP S5 compared to MAP K10. MAP 'Bison type' S5 also showed polymorphic profile for LSP(P)4. Polymorphism was also observed in SSRs. This pilot study may form the basis for future epidemiological investigations.     

Immunoglobulin isotypes in sera and nasal mucosal secretions and their neonatal transfer and distribution in horses

OBJECTIVE: To determine concentrations of IgA and IgG subclasses in serum, colostrum, milk, and nasal wash samples of adult horses and foals. ANIMALS: Seven 2-year-old Welsh ponies, 27 adult mixed-breed horses, and 5 Quarter Horse mares and their foals. PROCEDURE: Serum was obtained from ponies and adult horses. Colostrum and milk were obtained from mares and serum and nasal wash samples from their foals immediately after parturition and on days 1, 7, 14, 28, 42, and 63. Nasal wash samples were also obtained from 23 adult horses. Concentrations of immunoglobulins were determined by use of inhibition ELISA. To determine transfer of maternal isotypes to foals, concentrations in colostrum and milk were compared with those in foal serum. Serum half-lives of isotypes in foals were also determined. RESULTS: IgGb was the most abundant isotype in serum and colostrum from adult horses, whereas IgA was the predominant isotype in milk. The major isotype in nasal secretions of adult horses and foals > or = 28 days old was IgA, but IgGa and IgGb were the major isotypes in nasal secretions of foals < or = 14 days old. Serum half lives of IgGa, IgGb, IgG(T), and IgA in foals were 176, 32, 21, and 3.4 days, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The early immunoglobulin repertoire of neonatal foals comprised IgGa, IgG(T), and IgA; endogenous synthesis of IgGb could not be detected until 63 days after birth. The restricted repertoire of immunoglobulins in foals may influence humoral immune responses to vaccination.     

Nutrient Management for Sustaining Productivity of Sunflower-Based Cropping Sequence in Indian Semiarid Regions

A comprehensive long-term study (2006–2010) was undertaken to develop a balanced and integrated nutrient supply system for sunflower-based cropping sequence considering the efficient utilization of residual and cumulative soil nutrient balance along with added fertilizers by the crops grown in rotation. The fertilizer application was done in potato and sunflower while greengram was raised as such on their residual effect. Significant response in yield was observed with 150% of the recommended nitrogen, phosphorus and potassium (NPK) or inclusion of farmyard manure (FYM) with the recommended NPK in the cropping sequence indicating 6.2–7.0% gain in system productivity over the existing recommendations. Each additional unit of P and K nutrition prompted system productivity by 18.9 and 11.0 kg kg^?1 of applied nutrient, respectively. Apparent yield decline was observed in K and PK omission plots to the extent of 15.8 and 27.4% in potato, 10.5 and 23.9% in sunflower and 4.2 and 8.3% in greengram, respectively, compared to the recommended fertilization. The superiority of the FYM along with the recommended NPK (potato/sunflower) was evident on the overall profitability and sustainability of the system, highlighted by the significantly higher productivity (7.16 t SFEY ha^?1), sustainability yield index (SYI; 0.76), production efficiency (PE; 27.85 kg SFEY ha^?1 day^?1) and net returns (2520 USD ha^?1) with a B:C ratio of 2.91. Apparent change in potassium permanganate (KMnO₄)-N was negative in all the treatments while N and P balance was positive with 150% NPK fertilization. Nutrient uptake exceeded the replenishment with 100% NPK application and maintained net negative soil nutrient stock for all the primary nutrients, indicating the need for revalidation of the existing recommendations in the system perspective. Conspicuous improvement in residual soil fertility in terms of maximum buildup of soil organic carbon (14%) and enhancement in soil KMnO₄-N (4.2%), Olsen-P (19.4%), ammonium acetate (NH4OAc)-K (5.8%) and dehydrogenase enzyme activity (44.4%) was observed in FYM-treated plots over the initial values. The study suggested that the inclusion of legumes and FYM application with the recommended NPK in potato-sunflower cropping sequence will sustain the system’s productivity through the efficient use of nutrients, enhanced microbial activity and improved soil health while combating escalating prices of fertilizers as well as environmental issues in the Indo-Gangetic plains of India and similar environments.     

Genetic analysis of Ankamali pigs of India using microsatellite markers and their comparison with other domesticated Indian pig types

Ankamali pigs, the domesticated native pigs of Kerala province of India were genetically characterized using 23 FAO recommended microsatellite markers and were compared with other native Indian pig types and Large White pigs. Twenty‐six blood samples were collected from genetically unrelated animals from their breeding tract and DNA was isolated by standard procedure of phenol/chloroform. The genomic DNA was amplified by polymerase chain reaction (PCR) at these 23 microsatellite loci, which were also used earlier to characterize Desi (North Indian) and Gahuri (North‐East Indian) pigs, the other two native domesticated pig types of India. The PCR products were resolved by denaturing urea‐polyacrylamide gel electrophoresis and alleles were visualized after silver nitrate staining. The data were analysed for allele size range, number of alleles, allelic frequencies, heterozygosity and polymorphism information content for each locus. The allele size range varied between 92–108 bp at locus S0026 and 280–296 bp at locus IGF‐1. The total number of alleles varied between five (S0178 and S0386) and 11 (S0355). The mean observed and expected heterozygosities were found to be 0.74 ± 0.09 and 0.83 ± 0.03 respectively. In the neighbour‐joining dendrogram based on D_A genetic distances developed after 1000 bootstraps, the Ankamali pigs did not show genetic closeness either with other native Indian pig types or exotic Large White pigs with high bootstrap values indicating genetic distinctness of Ankamali pigs.