Microbial Volatile Organic Compounds: Insights into Plant Defense.

Volatile organic compounds (VOCs) are low molecular weight molecules that tend to evaporate easily at room temperature because of their low boiling points. VOCs are emitted by all organisms; therefore, inter- and intra-kingdom interactions have been established, which are fundamental to the structuring of life on our planet. One of the most studied interactions through VOCs is between microorganism VOCs (mVOCs) and plants, including those of agricultural interest. The mVOC interactions generate various advantages for plants, ranging from promoting growth to the activation of defense pathways triggered by salicylic acid (systemic acquired resistance) and jasmonic acid (induced systemic resistance) to protect them against phytopathogens. Additionally, mVOCs directly inhibit the growth of phytopathogens, thereby providing indirect protection to plants. Among the current agricultural problems is the extensive use of chemicals, such as fertilizers, intended to combat production loss, and pesticides to combat phytopathogen infection. This causes problems in food safety and environmental pollution. Therefore, to overcome this problem, it is important to identify alternatives that do not generate environmental impacts, such as the application of mVOCs. This review addresses the protective effects of mVOCs emitted by microorganisms from different kingdoms and their implications in plant defense pathways.

In vitro and ex vivo anti-Pythium insidiosum potential of ozonated sunflower oil.

This study sought to evaluate the in vitro and ex vivo susceptibility of Pythium insidiosum to ozonized sunflower oil (OSO) and verify the morphological alterations of OSO-exposed hyphae. Susceptibility assays were performed according to the broth microdilution protocol M38-A2/CLSI, and the minimal inhibitory (MIC) and minimal oomicidal (MOC) concentrations were also determined. Non-ozonated sunflower oil (SO) was used as the oil control. Additionally, kunkers from equine pythiosis were exposed to OSO. Damages caused by OSO and SO on P. insidiosum hyphae ultrastructure were verified using scanning electron microscopy. The MIC range for OSO was 7000 to 437.5 mg/mL, and the values for SO were higher, ranging from 56000 to 14000 mg/mL. The MOC was equal to MIC for both oil formulations. The OSO fully inhibited the oomycete growth from kunkers, although there was P. insidiosum growth in the kunker control in 24 h of incubation. The SEM analyses showed that both OSO and SO caused morphological alterations in P. insidiosum hyphae, highlighting the presence of cavitation along the hyphae with loss of continuity of the cell wall, which was more evident in the OSO-treated hyphae. The OSO had the best oomicidal activity, leading us to believe that our findings may support future research containing this formulation to be applied in integrative medicine protocols to control pythiosis in animals and humans.

Synchrospora gen. nov., a New Peronosporaceae Genus with Aerial Lifestyle from a Natural Cloud Forest in Panama.

During a survey of Phytophthora diversity in Panama, fast-growing oomycete isolates were obtained from naturally fallen leaves of an unidentified tree species in a tropical cloud forest. Phylogenetic analyses of sequences from the nuclear ITS, LSU and ßtub loci and the mitochondrial cox1 and cox2 genes revealed that they belong to a new species of a new genus, officially described here as Synchrospora gen. nov., which resided as a basal genus within the Peronosporaceae. The type species S. medusiformis has unique morphological characteristics. The sporangiophores show determinate growth, multifurcating at the end, forming a stunted, candelabra-like apex from which multiple (8 to >100) long, curved pedicels are growing simultaneously in a medusa-like way. The caducous papillate sporangia mature and are shed synchronously. The breeding system is homothallic, hence more inbreeding than outcrossing, with smooth-walled oogonia, plerotic oospores and paragynous antheridia. Optimum and maximum temperatures for growth are 22.5 and 25-27.5 °C, consistent with its natural cloud forest habitat. It is concluded that S. medusiformis as adapted to a lifestyle as a canopy-dwelling leaf pathogen in tropical cloud forests. More oomycete explorations in the canopies of tropical rainforests and cloud forests are needed to elucidate the diversity, host associations and ecological roles of oomycetes and, in particular, S. medusiformis and possibly other Synchrospora taxa in this as yet under-explored habitat.

Promising use of nanotechnology in Pythium insidiosum: a systematic review / Utilização promissora de nanotecnologia em Pythium insidiosum: uma revisão sistemática

ABSTRACT: The aquatic oomycete Pythium insidiosum is an emerging pathogen highly relevant in human and veterinary medicine and an etiologic agent of pythiosis, a disease of worldwide distribution mainly affecting horses, dogs, and humans, presenting cutaneous, subcutaneous, ocular, gastrointestinal, and systemic forms. The available therapeutic methods to treat this disease and its forms are not entirely effective, thus highlighting the need to investigate the forms of treatments with better efficacy, such as compounds from different pharmacological classes, compounds of natural origin, and new technological alternatives, including nanotechnology. Therefore, this study evaluated scientific publications regarding the use of nanotechnology in P. insidiosum treatment. For this, a systematic literature review, was carried out on articles published from 2010 to 2022 on the LILACS, MEDLINE, Google Scholar, PubMed, and SciELO databases using the descriptors 'Pythium insidiosum,' 'pythiosis,' 'nanotechnology,' 'nanoparticles,' 'nanoemulsion,' and 'treatment.' We reported 162 articles for the researched theme; although, only four studies were included because they met the criteria established herein. A meta-analysis was used for the statistical analysis of the data obtained in vitro studies, and we reported the use of nanotechnology can be a promising alternative in developing antimicrobial compounds with anti-P. insidiosum activity. Nevertheless, additional research is needed to verify the potential use of this technology in clinical therapy against P. insidiosum infections.

RESUMO: O oomiceto aquático Pythium insidiosum é um patógeno emergente de relevância em medicina humana e veterinária. É o agente etiológico da pitiose, uma enfermidade de distribuição mundial, que acomete principalmente em equinos, caninos e seres humanos, podendo apresentar-se nas formas cutâneas, subcutâneas, oculares, gastrointestinais e sistêmicas. Considerando que os métodos terapêuticos disponíveis para o tratamento da doença não são completamente efetivos, há uma necessidade de investigar formas de tratamentos com melhor eficácia, como os compostos de diferentes classes farmacológicas, compostos de origem natural, bem como, novas alternativas tecnológicas, incluindo a nanotecnologia. Deste modo, este trabalho objetivou avaliar publicações científicas referentes a utilização de nanotecnologia em P. insidiosum. Para isso, realizou-se uma revisão sistemática da literatura, buscando artigos no período de 2010 a 2022, nas bases de dados LILACS, MEDLINE, Google Scholar, PubMed e SciELO, utilizando-se os descritores Pythium insidiosum, pitiose, nanotecnologia, nanopartículas, nanoemulsão e tratamento. Encontrou-se 162 artigos com familiaridade a temática pesquisada; no entanto, apenas quatro estudos foram incluídos, pois atendiam os critérios estabelecidos na pesquisa. Para análise estatística dos dados obtidos nos estudos in vitro, utilizou-se meta-análise. Demonstrou-se o promissor uso de nanotecnologia como alternativa no desenvolvimento de compostos antimicrobianos com atividade anti-P. insidiosum. Entretanto, constata-se que estudos adicionais se fazem necessários para verificar o potencial uso desta tecnologia na terapêutica clínica contra infecções por P. insidiosum.

Biosíntesis inducida de fengicina y surfactina en una cepa de Bacillus amyloliquefaciens con actividad oomiceticida sobre zoosporas de Phytophthora capsica / Induced biosynthesis of fengycin and surfactin in a strain of Bacillus amyloliquefaciens with oomyceticidal activity on zoospores of Phytophthora capsici

Resumen La aplicación de metabolitos antimicrobianos biosintetizados por especies de Bacillus es una alternativa potencial para controlar Phytophthora capsici (P. capsici) en hortalizas y podría evitar el uso de productos químicos con acción oomiceticida. El objetivo de este estudio fue evaluar el impacto de la adición al medio de cultivo de distintos agentes (ácido glutámico, hierro, celulosa, quitina y células inactivas de Colletotrichum spp.) sobre la biosíntesis de lipopéptidos en Bacillus amyloliquefaciens KX953161.1 y examinar la capacidad oomiceticida de dichos compuestos in vitro sobre las zoosporas de P. capsici. Los lipopéptidos identificados y cuantificados por cromatografía en capa fina de alta resolución (HPTLC) en los extractos crudos fueron fengicina y surfactina. El cultivo bacteriano adicionado con células inactivas de Colletotrichum spp. demostró la mayor biosíntesis de lipopéptidos: 1.847,02 ±11,8 pg/mL de fengicina y 2.563,45 ± 18,4 pg/mL de surfactina. Los tratamientos con menor producción de estos lipopéptidos fueron aquellos a los que se añadió hierro (608,05 ± 22,6 pg/mL de fengicina y 903,74 ±22,1 pg/mL de surfactina) o celulosa (563,31 ±11,9 y 936,96 ±41,1 pg/mL, igual orden). El extracto con los lipopéptidos presentó una inhibición del 100% en la germinación de zoosporas de P. capsici, se observó enquistamiento, malformaciones en el tubo germinal y degradación celular. Se concluye que los lipopéptidos producidos por B. amyloliquefaciens KX953161.1 podrían contribuir al control de P. capsici, sin embargo, se requieren más estudios a fin de elucidar el modo de acción biológica de estos compuestos y optimizar el perfil de producción y el rendimiento.

Abstract A potential alternative to the use of chemical products with oomyceticidal action for the control of Phytophthora capsici in vegetables is the use of antimicrobial metabolites, biosynthesized in Bacillus species. The objective of this study was to induce the biosynthesis of lipopeptides in Bacillus amyloliquefaciens KX953161.1 by using glutamic acid, iron, cellulose, chitin, or inactive Colletotrichum spp. cells. The in vitro oomyceticidal effect of the bacterial lipopeptides on zoospores of Phytophthora capsici was evaluated. The lipopeptides identified and quantified in the crude extracts by high performance thin layer chromatography (HPTLC) were fengycin and surfactin. The bacterial culture with inactive fungal cells yielded the greatest biosynthesis of lipopeptides, at 1847.02± 11.8 and 2563.45± 18.4 pg/ml of fengycin and surfactin, respectively and the treatments that obtained lower production of these lipopepti-des, were those to which iron and cellulose were added with 608.05 ± 22.6 and 903.74± 22.1; 563.31± 11.9 and 936.96± 41.1 pg/ml for fengicin and surfactin, respectively. The lipopeptide extracted showed 100% germination inhibition on zoospores of P. capsici, revealing encystment, malformations in the germ tube and cellular degradation. Lipopeptides have the potential to control P. capsici; however, the biosynthesis of these lipopeptides requires further study to determine their biological mode of action and optimize lipopeptide performance and profile.

A Retrospective Study of Pythiosis in Domestic Animals in Northeastern Brazil.

Pythiosis is an endemic disease in northeastern Brazil and we now report the epidemiological, clinical and pathological findings in a retrospective study of naturally occurring cases in domestic animals. From January 1985 to December 2020, the Laboratory of Animal Pathology of the Federal University of Campina Grande examined 13,542 tissue samples from necropsies and biopsies. Among these samples, 306 were diagnosed as pythiosis: 195 cases in horses, 75 in sheep, 19 in dogs, six in mules, four in cattle, three in cats, two in goats, one in a donkey and one in an ostrich. Affected equids had lesions in the skin, mammary glands and nasal cavities. Affected sheep had cutaneous, nasal and digestive lesions while cattle and goats had cutaneous lesions. Carnivores developed lesions, mainly in the alimentary tract, of sufficient severity to cause death or result in euthanasia. The single affected bird had lesions in the alimentary tract and surgical excision resulted in remission. The disease had a long and life-threatening clinical course in most affected species but resolved spontaneously in cattle. Clinical signs were directly related to the location of the lesions, which were invariably characterized by chronic inflammation associated with intralesional hyphae. Veterinary clinicians and pathologists should be familiar with the clinicopathological features of pythiosis and the wide range of susceptible animal species.

[Induced biosynthesis of fengycin and surfactin in a strain of Bacillus amyloliquefaciens with oomyceticidal activity on zoospores of Phytophthora capsici]. / Biosíntesis inducida de fengicina y surfactina en una cepa de Bacillus amyloliquefaciens con actividad oomiceticida sobre zoosporas de Phytophthora capsica.

A potential alternative to the use of chemical products with oomyceticidal action for the control of Phytophthora capsici in vegetables is the use of antimicrobial metabolites, biosynthesized in Bacillus species. The objective of this study was to induce the biosynthesis of lipopeptides in Bacillus amyloliquefaciens KX953161.1 by using glutamic acid, iron, cellulose, chitin, or inactive Colletotrichum spp. cells. The in vitro oomyceticidal effect of the bacterial lipopeptides on zoospores of Phytophthora capsici was evaluated. The lipopeptides identified and quantified in the crude extracts by high performance thin layer chromatography (HPTLC) were fengycin and surfactin. The bacterial culture with inactive fungal cells yielded the greatest biosynthesis of lipopeptides, at 1847.02± 11.8 and 2563.45± 18.4 µg/ml of fengycin and surfactin, respectively and the treatments that obtained lower production of these lipopeptides, were those to which iron and cellulose were added with 608.05 ± 22.6 and 903.74± 22.1; 563.31± 11.9 and 936.96± 41.1 µg/ml for fengicin and surfactin, respectively. The lipopeptide extracted showed 100% germination inhibition on zoospores of P. capsici, revealing encystment, malformations in the germ tube and cellular degradation. Lipopeptides have the potential to control P. capsici; however, the biosynthesis of these lipopeptides requires further study to determine their biological mode of action and optimize lipopeptide performance and profile.

Experimental Pythium aphanidermatum Infection in Rabbits.

Pythium aphanidermatum is a common plant pathogen, reportedly capable of human infection. This study investigated whether P. aphanidermatum can infect domestic rabbits. Four rabbits were inoculated with P. aphanidermatum subcutaneously and evaluated for 30 days. Blood and tissue samples were collected from all animals. The animals developed palpable nodules 5-10 days after inoculation. Necropsy revealed caseous nodular lesions characterized histopathologically by pyogranulomatous inflammation containing hyphae in the necrotic areas. P. aphanidermatum was isolated from the caseous material and anti-P. aphanidermatum antibodies were detected by serological examination. This is the first report of experimental P. aphanidermatum infection in mammals. The results demonstrate that this oomycete can produce infection at the inoculation site and induce an immune response. The results suggest that P. aphanidermatum may be undergoing adaptation to vertebrate hosts.

Oomycete intracellular effectors: specialised weapons targeting strategic plant processes.

Oomycete phytopathogens have adapted to colonise plants using effectors as their molecular weapons. Intracellular effectors, mostly proteins but also small ribonucleic acids, are delivered by the pathogens into the host cell cytoplasm where they interfere with normal plant physiology. The diverse host processes emerging as 'victims' of these 'specialised bullets' include gene transcription and RNA-mediated silencing, cell death, protein stability, protein secretion and autophagy. Some effector targets are directly involved in defence execution, while others participate in fundamental metabolisms whose alteration collaterally affects defences. Other effector targets are susceptibility factors (SFs), that is host components that make plants vulnerable to pathogens. SFs are mostly negative regulators of immunity, but some seem necessary to sustain or promote pathogen colonisation.

Metastatic calcification and granulomatous grastroenteritis associated to Pythium insidiosum in a dog

Pythiosis is a granulomatous process of which the oomycete Pythium insidiosum is its etiological agent. It can affect animals and humans alike and its infection occurs when free zoospores in the water get in contact with the target tissues and encyst. The disease often occurs in tropical places with abundance of water and aquatic plants that host the fungus. Dogs infection is predominantly gastric with granuloma formations in the stomach and intestine with progressive signs of vomiting, weight loss and diarrhea. In this case report, we described clinical, surgical, necroscopic and histopathological findings of a one year and two months old, male boxer that presented clinical signs of anorexia and persistent vomiting. It was noticed on ultrasound examination an increase in stomach and intestine thickness. Laparotomy confirmed a mass affecting the gastric wall which, an incision biopsy, showed an abundant fibrous tissue associated with granulomatous reaction that was surrounded by tubuliform structures. Due to clinical complications, euthanasia was performed and in necroscopic examination a markedly increased stomach and duodenum was observed. An; histological examination of this areas it was observed that they contained granulation tissue with giant cells and epithelioids macrophages around necrosed areas associated with lymphocytes infiltrate. Also, it was possible to observe tubuliform structures by the Grocott-Gomoris Methenamine Silver (GMS) stain, this finding is compatible with the agent Pythium insidiosum. Therefore, this presumptive identification was confirmed by PCR analysis which amplicon had 97.83% similarity with current available genomic sequence of P. insidiosum.(AU)

Metastatic calcification and granulomatous grastroenteritis associated to Pythium insidiosum in a dog

Pythiosis is a granulomatous process of which the oomycete Pythium insidiosum is its etiological agent. It can affect animals and humans alike and its infection occurs when free zoospores in the water get in contact with the target tissues and encyst. The disease often occurs in tropical places with abundance of water and aquatic plants that host the fungus. Dogs infection is predominantly gastric with granuloma formations in the stomach and intestine with progressive signs of vomiting, weight loss and diarrhea. In this case report, we described clinical, surgical, necroscopic and histopathological findings of a one year and two months old, male boxer that presented clinical signs of anorexia and persistent vomiting. It was noticed on ultrasound examination an increase in stomach and intestine thickness. Laparotomy confirmed a mass affecting the gastric wall which, an incision biopsy, showed an abundant fibrous tissue associated with granulomatous reaction that was surrounded by tubuliform structures. Due to clinical complications, euthanasia was performed and in necroscopic examination a markedly increased stomach and duodenum was observed. An; histological examination of this areas it was observed that they contained granulation tissue with giant cells and epithelioids macrophages around necrosed areas associated with lymphocytes infiltrate. Also, it was possible to observe tubuliform structures by the Grocott-Gomori’s Methenamine Silver (GMS) stain, this finding is compatible with the agent Pythium insidiosum. Therefore, this presumptive identification was confirmed by PCR analysis which amplicon had 97.83% similarity with current available genomic sequence of P. insidiosum.

In vitro anti-Pythium insidiosum activity of amorolfine hydrochloride and azithromycin, alone and in combination.

Pythium insidiosum infections have been widely studied in an attempt to develop an effective therapeutic protocol for the treatment of human and animal pythiosis. Several antifungal agents are still prescribed against this oomycete, although they present contradictory results. To evaluate the susceptibility profile and to verify the morphological alterations in P. insidiosum isolates treated with amorolfine hydrochloride and azithromycin, alone or in combination. Susceptibility tests for P. insidiosum isolates (n = 20) against amorolfine hydrochloride (AMR) and azithromycin (AZM) were performed according to Clinical and Laboratory Standards Institutes (CLSI) protocol M38-A2. Combinations of both drugs were evaluated using the checkerboard microdilution method. Additionally, transmission and scanning electron microscopy were performed in order to verify the morphological alterations in P. insidiosum isolates in response to these drugs. All P. insidiosum isolates had a minimum inhibitory concentration (MIC) ranging from 16 to 64 mg/l and 8 to 64 mg/l for amorolfine hydrochloride and azithromycin, respectively. Synergistic interactions between the drugs were not observed, with antagonism in 59.8% of isolates, and indifferent interactions in 36.2%. Electron microscopy showed changes in the surface of P. insidiosum hyphae, disorganization of intracellular organelles, and changes in the plasma membrane and cell wall of oomycetes treated with the drugs. This is the first study to demonstrate in vitro anti-P. insidiosum effect of amorolfine hydrochloride. These results indicate the therapeutic potential of this drug against cutaneous and subcutaneous forms of pythiosis, but further studies are necessary to confirm this potential.

Inhibition of the lemon brown rot causal agent Phytophthora citrophthora by low-toxicity compounds.

BACKGROUND: Phytophthora spp., soil-borne oomycetes, cause brown rot (BR) on postharvest lemons. The management of this disease is based on cultural practices and chemical control using inorganic salts of limited efficacy. In the search for new alternatives, the aim of this work was to evaluate the effect of low-toxicity compounds to inhibit the growth of P. citrophthora and to control BR disease on lemons. Sodium bicarbonate, potassium sorbate, polyhexamethylene guanidine, Ascophyllum nodosum extract and a formulation containing phosphite salts plus A. nodosum (P+An) were evaluated. RESULTS: All tested products inhibited mycelial growth, sporangia formation and zoospore germination of P. citrophthora in vitro. In postharvest applications on artificially inoculated lemons, only P+An exhibited a BR curative effect, with incidence reduction of around 60%. When this formulation was applied in field treatments, BR incidence was reduced by 40% on lemons harvested and inoculated up to 30 days post application. CONCLUSION: Our results demonstrate the in vitro direct anti-oomycete effect of low-toxicity compounds and the in vivo efficacy of P+An formulation to control BR, encouraging the incorporation of the latter in the management of citrus BR. © 2020 Society of Chemical Industry.

Segmental enteritis associated with Pythium insidiosum infection in a horse

Background: Pythiosis is an infectious disease caused by the oomycete Pythium insidiosum, with higher occurrence in wetlands and hot climate regions. This microorganism develops its cycle in aquatic plants, and most cases happen because of the contact of animals or people with water containing the motile zoospores (infectious form). Horses are the principal species affected and develop principally cutaneous and subcutaneous lesions, but the gastrointestinal tract is seldom affected. Humans develop various forms of pythiosis, such as a vascular form. The objectives of the current study are to describe an unusual case of intestinal pythiosis, its clinical signs, aspects of pathogenesis, and diagnosis. Case: A 13-year-old Crioula mare, from Santa Maria, RS, Brazil, presented with reduced food and water intake, apathy, restlessness, rolling, nasal reflux, firm abdomen upon palpation, and tachypnea during 2 days. The horses of this farm were fed native pasture and horse feed, and they had access to a nearby pond. Two days following the start of the clinical signs, the horse died and was necropsied on the farm. During necropsy, there was around 400 mL of reddish effusion in the abdominal cavity (modified transudate). A 15 cm segment of jejunum was firm upon palpation and had a severe transmural thickening. The wall of the affected area was up to 3 cm in thickness and firm, with small yellowish and irregular masses that stood out and looked friable, interpreted as kunkers. Microscopically, the yellowish masses (kunkers) were characterized by dense accumulations of intact and degenerate eosinophils (eosinophilic necrosis). Within these kunkers, and also on their periphery, there were multiple negatively stained hyphal profiles. Hyphae were also seen on the wall of small arteries inside the kunkers. These hyphae had nearly parallel walls and were occasionally...(AU)

The Climate-Driven Genetic Diversity Has a Higher Impact on the Population Structure of Plasmopara viticola Than the Production System or QoI Fungicide Sensitivity in Subtropical Brazil.

Downy mildew, caused by Plasmopara viticola, is the main disease affecting vineyards in subtropical Brazil. Here, we collected 94 P. viticola isolates from four organic and conventional vineyards in the two main grape-growing states of Brazil to evaluate the sensitivity to the quinone outside inhibitor (QoI) azoxystrobin by pheno- and genotyping assays. The impact of location, production system and sensitivity to QoI fungicides on the population genetics and structure of P. viticola was determined using 10 microsatellite markers. Cytochrome b sequencing revealed that 28 and 100% of the isolates from vineyards under organic and conventional management carried the G143A mutation, respectively. The G143A mutation was associated with high levels of azoxystrobin resistance. Three out of the 94 isolates analyzed carried the M125I alteration, not previously described in P. viticola, which was associated with a five-fold reduction in azoxystrobin sensitivity compared to wild-type isolates. Haplotype network analysis based on cytochrome b gene sequences suggested that the Brazilian populations are more closely related to the European than the North American population. A total of six haplotypes were identified, with two of them carrying the G143A mutation. Microsatellite analysis revealed high allelic and genotypic variation among the four populations. Population differentiation analyses indicated that state of origin directly influences the population biology of P. viticola, while production system and QoI sensitivity have little effect. Great genetic diversity, sexual reproduction and high levels of admixture were observed in Rio Grande do Sul State. In contrast, populations in São Paulo State were dominated by a few clonal genotypes, and no admixed genotype was detected between the two genetic pools identified in the state. This study raises the hypothesis that winter weather conditions influence the overwinter survival strategy with profound effects in the population biology of P. viticola.

Pythiosis in cats in northeastern Brazil.

The epidemiological, clinical and anatomopathological aspects of pythiosis in cats in northeastern Brazil are described. From January 2000 to December 2018 the Laboratory of Animal Pathology of the Federal University of Campina Grande received 1928 tissue samples of cats, three of which were diagnosed as pythiosis. Grossly, the cats showed a multinodular mass in the oral cavity associated with facial deformity (case 1), a large multinodular mass thickening the jejunum wall (case 2), and an ulcerated nodule in the skin at the base of the tail (case 3). Histologically, pyogranulomatous inflammation and necrosis, with intralesional predominantly negatively stained hyphae, were observed in all cases. Immunohistochemistry for Pythium insidiosum revealed strong immunolabelling of the hyphae. The diagnosis of pythiosis was based on the epidemiological, clinical and anatomopathological findings, and was confirmed by immunohistochemistry. Although uncommon in cats, pythiosis should be readily considered as a differential diagnosis of chronic pyogranulomatous infections of the gastrointestinal tract and skin, especially in endemic areas, where the disease is often diagnosed in other animal species.

Pythiosis in cattle in Northeastern Brazil / Pitiose em bovinos no Nordeste do Brasil

The epidemiological, clinical and pathological aspects of cutaneous pythiosis occurring in cattle from three farms in the Northeastern of Brazil are described. A biopsy of the lesions of one bovine from each farm was performed. In two cases, the affected cattle had contact with water accumulated in dams during the dry season in the semiarid region. Another case occurred in the coastal tropical region in cattle grazing around irrigation channels. Clinically, lesions were observed mainly on the skin of the thoracic and/or pelvic limbs, characterized by flat and irregular ulcerated areas or nodules of varying sizes, some with fistulous tracts penetrating deep into the subcutaneous tissue. In one case the regional lymph nodes were affected. Histologically, in all cases, pyogranulomatous dermatitis associated with negative hyphae images, in hematoxylin-eosin stained sections, were observed. In sections stained by Grocott methenamine silver, the hyphae measured 2-8μm and had irregular ramifications and rare septations. Immunohistochemistry technique demonstrated strong immunolabeling for Pythium insidiosum. Pythiosis should be included in the differential diagnosis of dermatopathies in cattle in the Northeastern of Brazil.(AU)

Descrevem-se os aspectos epidemiológicos, clínicos e patológicos da pitiose cutânea em bovinos de três propriedades do Nordeste do Brasil. Uma biópsia das lesões de um bovino de cada propriedade foi realizada. Em dois casos, os bovinos afetados tiveram acesso à água acumulada em açudes durante a estação seca da região semiárida. O outro bovino acometido estava a pastoreio próximo a canais de irrigação na região litorânea. Clinicamente, as lesões foram observadas principalmente na pele dos membros torácicos e/ou pélvicos e caracterizavam-se por áreas planas e irregulares de ulceração ou nódulos de tamanhos variados, alguns com trajetos fistulosos penetrando profundamente no tecido subcutâneo. Em um caso, os linfonodos regionais foram afetados. Histologicamente, em todos os casos, observou-se dermatite piogranulomatosa associada a imagens negativas de hifas, em secções corados por hematoxilina e eosina. Em seções coradas por metenamina de prata de Grocott, as hifas mediam 2-8μm e possuíam ramificações irregulares com raras septações. A imuno-histoquímica demonstrou forte imunomarcação para Pythium insidiosum. A pitiose deve ser incluída como diagnóstico diferencial de dermatopatias de bovinos no Nordeste do Brasil.(AU)

Pythiosis in cattle in Northeastern Brazil / Pitiose em bovinos no Nordeste do Brasil

The epidemiological, clinical and pathological aspects of cutaneous pythiosis occurring in cattle from three farms in the Northeastern of Brazil are described. A biopsy of the lesions of one bovine from each farm was performed. In two cases, the affected cattle had contact with water accumulated in dams during the dry season in the semiarid region. Another case occurred in the coastal tropical region in cattle grazing around irrigation channels. Clinically, lesions were observed mainly on the skin of the thoracic and/or pelvic limbs, characterized by flat and irregular ulcerated areas or nodules of varying sizes, some with fistulous tracts penetrating deep into the subcutaneous tissue. In one case the regional lymph nodes were affected. Histologically, in all cases, pyogranulomatous dermatitis associated with negative hyphae images, in hematoxylin-eosin stained sections, were observed. In sections stained by Grocott methenamine silver, the hyphae measured 2-8μm and had irregular ramifications and rare septations. Immunohistochemistry technique demonstrated strong immunolabeling for Pythium insidiosum. Pythiosis should be included in the differential diagnosis of dermatopathies in cattle in the Northeastern of Brazil.(AU)

Descrevem-se os aspectos epidemiológicos, clínicos e patológicos da pitiose cutânea em bovinos de três propriedades do Nordeste do Brasil. Uma biópsia das lesões de um bovino de cada propriedade foi realizada. Em dois casos, os bovinos afetados tiveram acesso à água acumulada em açudes durante a estação seca da região semiárida. O outro bovino acometido estava a pastoreio próximo a canais de irrigação na região litorânea. Clinicamente, as lesões foram observadas principalmente na pele dos membros torácicos e/ou pélvicos e caracterizavam-se por áreas planas e irregulares de ulceração ou nódulos de tamanhos variados, alguns com trajetos fistulosos penetrando profundamente no tecido subcutâneo. Em um caso, os linfonodos regionais foram afetados. Histologicamente, em todos os casos, observou-se dermatite piogranulomatosa associada a imagens negativas de hifas, em secções corados por hematoxilina e eosina. Em seções coradas por metenamina de prata de Grocott, as hifas mediam 2-8μm e possuíam ramificações irregulares com raras septações. A imuno-histoquímica demonstrou forte imunomarcação para Pythium insidiosum. A pitiose deve ser incluída como diagnóstico diferencial de dermatopatias de bovinos no Nordeste do Brasil.(AU)

Segmental enteritis associated with Pythium insidiosum infection in a horse

Background: Pythiosis is an infectious disease caused by the oomycete Pythium insidiosum, with higher occurrence in wetlands and hot climate regions. This microorganism develops its cycle in aquatic plants, and most cases happen because of the contact of animals or people with water containing the motile zoospores (infectious form). Horses are the principal species affected and develop principally cutaneous and subcutaneous lesions, but the gastrointestinal tract is seldom affected. Humans develop various forms of pythiosis, such as a vascular form. The objectives of the current study are to describe an unusual case of intestinal pythiosis, its clinical signs, aspects of pathogenesis, and diagnosis. Case: A 13-year-old Crioula mare, from Santa Maria, RS, Brazil, presented with reduced food and water intake, apathy, restlessness, rolling, nasal reflux, firm abdomen upon palpation, and tachypnea during 2 days. The horses of this farm were fed native pasture and horse feed, and they had access to a nearby pond. Two days following the start of the clinical signs, the horse died and was necropsied on the farm. During necropsy, there was around 400 mL of reddish effusion in the abdominal cavity (modified transudate). A 15 cm segment of jejunum was firm upon palpation and had a severe transmural thickening. The wall of the affected area was up to 3 cm in thickness and firm, with small yellowish and irregular masses that stood out and looked friable, interpreted as kunkers. Microscopically, the yellowish masses (kunkers) were characterized by dense accumulations of intact and degenerate eosinophils (eosinophilic necrosis). Within these kunkers, and also on their periphery, there were multiple negatively stained hyphal profiles. Hyphae were also seen on the wall of small arteries inside the kunkers. These hyphae had nearly parallel walls and were occasionally...

Genome Sequence Data of Six Isolates of Phytophthora capsici from Mexico.

Phytophthora capsici is an oomycete plant pathogen with a wide host range. Worldwide, P. capsici is known for causing the principal disease of chili pepper crops. Our goal was to expand the available genome resources for this diverse pathogen by generating whole-genome sequences for six isolates of P. capsici from Mexico.