Eulógio Carlos Queiroz de Carvalho

Apa antigen of Mycobacterium avium subsp. paratuberculosis as a target for species-specific immunodetection of the bacteria in infected tissues of cattle with paratuberculosis

Comparative genomics of Mycobacterium spp. have revealed conservative genes and respective proteins differently expressed in mycobacteria that could be used as targets for the species-specific immunodiagnostics. The alanine and proline-rich antigen Apa is a mycobacterial protein that present significant variability in primary sequence length and composition between members of M. avium and M. tuberculosis complexes. In this study, the recombinant Apa protein encoded by the MAP1569/ModD gene of M. avium subsp. paratuberculosis (Map) was used to generate a panel of monoclonal antibodies which were shown to recognize the most important veterinary pathogens of the M. avium complex, specifically Map and M. avium subsp. hominissuis, and which did not cross-react with M. bovis or M. tuberculosis. The produced antibodies were demonstrated to be a useful tool for the species-specific immunofluorescence or immunohistochemical detection of Map in experimentally infected cell cultures or intestinal tissues from cattle with bovine paratuberculosis and, additionally, they may be employed for the discrimination of pathogenic M. avium subspecies via Western blotting.

Hypervirulent Mycobacterium tuberculosis strain triggers necrotic lung pathology associated with enhanced recruitment of neutrophils in resistant C57BL/6 mice

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb) that in most cases induces irreversible necrosis of lung tissue as a result of excessive inflammatory reactions. The murine model of TB in resistant C57BL/6 mice infected with reference Mtb strains is widely used in TB studies; however, these mice do not show a necrotic pathology, which restricts their use in studies of irreversible tissue damage. Recently, we demonstrated that necrotic lung lesions could be induced in the C57BL/6 mice by highly virulent Mtb strains belonging to the modern Beijing sublineage. However, the pathogenic mechanisms leading to necrosis in this model were not elucidated. In this study, we investigated the dynamics of lung lesions in mice infected with highly virulent Beijing Mtb strain M299, compared with those infected with laboratory Mtb strain H37Rv. The data demonstrate that necrotic lung lesions in mice infected by the strain M299 were associated with enhanced recruitment of myeloid cells, especially neutrophils, and increased levels of proinflammatory cytokines, consistent with exacerbated inflammation. High levels of IFN-γ production contributed to the control of bacterial growth. Further progression to chronic disease was associated with a reduction in the levels of inflammatory mediators in the lungs, the accumulation of foamy macrophages and partial healing of the necrotic tissue by fibrosis. At a late stage of disease, degradation of foamy cells resulted in the liberation of accumulated lipids and persisting bacilli and further activation of inflammation, which promoted lung consolidation. Overall, our studies show that C57BL/6 mice infected with highly virulent Mtb strain may serve as a TB model reproducing an exacerbated inflammatory response in a resistant host to hypervirulent mycobacteria, leading to irreversible necrotic lung lesions.

Pathologies of the digestive system caused by marine debris in Chelonia mydas

The growth of human population and deficient pollution control measures pose significant challenge to the environment. Despite conservation efforts, all sea turtle species are at some risk of extinction. The present study investigated the effect of marine debris on the gastrointestinal tract of green turtles in southeastern Brazil. Of the 777 animals evaluated, 290 showed marine debris in one segment of the gastrointestinal tract. The presence of these materials in the gastrointestinal tract may be harmful, independent of the segment involved, and increases the risk of impaction. Marine debris has become a significant hazard to Chelonia mydas in the region surveyed, causing perforation, rupture, or fecal impaction that, when not treated, is potentially fatal, exposing the intestine to bacterial infection.

Caracterização do processo de rigor mortis em músculos de eqüinos e maciez da carne

This work studied 12 horses at different ages butchered in a slaughterhouse in Minas Gerais State, Brazil (SIF 1803) and evaluated temperature, pH, sarcomere length in different periods after slaughter (1h, 5h, 8h, 10h, 12h, 15h, and 24 hours) as well as the shear force (meat tenderness) of the Longissimus dorsi and Semitendinosus muscles, aiming at characterizing the rigor mortis onset in the meat during industrial processing. The chilly room temperature varied from 10.2°C to 4.0°C, and the mean initial carcass temperature was 35.32°C and the final one was 4.15°C. The mean initial pH of Longissimus dorsi was 6.49 and the final one was 5.63; the mean initial pH of Semitendinosus was 6.44 and the final one was 5.70. The smallest sarcomere size obtained in both muscles occurred at 15 hours postmortem, and the sarcomere lengths were 1.44 µm and 1.41 µm, respectively. The meat from adult horses was tougher than that from young ones (p<0.05), and the Semitendinosus muscle was tougher than Longissimus dorsi muscle.

Toxoplasma gondii Oral Infection Induces Intestinal Inflammation and Retinochoroiditis in Mice Genetically Selected for Immune Oral Tolerance Resistance

Toxoplasmosis is a worldwide disease with most of the infections originating through the oral route and generates various pathological manifestations, ranging from meningoencephalitis to retinochoroiditis and inflammatory bowel disease. Animal models for these pathologies are scarce and have limitations. We evaluated the outcome of Toxoplasma gondii oral infection with 50 or 100 cysts of the ME-49 strain in two lines of mice with extreme phenotypes of susceptibility (TS) or resistance (TR) to immune oral tolerance. Therefore, the aim of this study was to evaluate the behaviour of TS and TR mice, orally infected by T. gondii, and determine its value as a model for inflammatory diseases study. Mortality during the acute stage of the infection for TR was 50% for both dosages, while 10 and 40% of the TS died after infection with these respective dosages. In the chronic stage, the remaining TS succumbed while TR survived for 90 days. The TS displayed higher parasite load with lower intestinal inflammation and cellular proliferation, notwithstanding myocarditis, pneumonitis and meningoencephalitis. TR presented massive necrosis of villi and crypt, comparable to inflammatory bowel disease, with infiltration of lymphoid cells in the lamina propria of the intestines. Also, TR mice infected with 100 cysts presented intense cellular infiltrate within the photoreceptor layer of the eyes, changes in disposition and morphology of the retina cell layers and retinochoroiditis. During the infection, high levels of IL-6 were detected in the serum of TS mice and TR mice presented high amounts of IFN-γ and TNF-α. Both mice lineages developed different disease outcomes, but it is emphasized that TR and TS mice presented acute and chronic stages of the infection, demonstrating that the two lineages offer an attractive model for studying toxoplasmosis.

Myrtenal-induced V-ATPase inhibition - A toxicity mechanism behind tumor cell death and suppressed migration and invasion in melanoma

BACKGROUND Metastatic tumor cells have acidic extracellular pH and differential electrochemical H+ gradients generated across their cell membranes by V-type H+-ATPases. This study shows that inhibition of the V-ATPases by the plant-derived monoterpene Myrtenal results in tumor cell death and decreased metastatic dissemination in mice. METHODS The Myrtenal anticancer toxicity was evaluated in vitro using murine (B16F0 and B16F10) and human (SkMel-5) melanoma cell lines, and in in vivo mouse metastatic dissemination model. Proton flux and extracellular acidification were directly evaluated at the surface of living cells using a non-invasive selective ion electrode approach. RESULTS The inhibition of V-ATPases by 100 μM Myrtenal disrupted the electrochemical H+ gradient across the cell membranes, strongly induced cell death (4-5 fold), and decreased tumor cells migration and invasion in vitro. Myrtenal (15 mg/kg) also significantly reduced metastasis induced by B16F10 in vivo, further reinforcing that V-ATPase is a molecular target to halt the progression of cancers. CONCLUSIONS These data revealed the therapeutic potential of Myrtenal as inhibitor of melanoma progression proposing a mechanism of action by which once inhibited by this monoterpene the proton pumps fail to activate cancer-related differential electrochemical gradients and H+ fluxes across the tumor cell membranes, disrupting pH signatures inherent in tumor progression, resulting in reprogrammed cell death and metastasis inhibition. GENERAL SIGNIFICANCE The work represents a new mechanistic strategy for contention of melanoma, the most aggressive and deadly form of cutaneous neoplasm, and highlights Myrtenal, other related monoterpenes and derivatives as promising proton pump inhibitors with high chemotherapeutic potential.

Chronic Cystitis Associated with Plesiochorus cymbiformis (Rudolphi, 1819) Looss, 1901 (Digenea: Gorgoderidae) in a Loggerhead Turtle Caretta caretta (Linnaeus 1758) (Testudines, Cheloniidae) from Brazil: A Case Report

Abstract This paper reports the first occurrence of Plesiochorus cymbiformis (Digenea: Gorgoderidae) in a loggerhead turtle (Caretta caretta [Testudines, Cheloniidae]) in Brazil and describes the histological findings of related injuries to the urinary bladder.

Tissue Lesions Due to Spirorchiid Eggs in a Loggerhead Turtle (Caretta caretta Linnaeus 1758) from Brazil: First Report Outside of the United States

Abstract Spirorchiids (family Spirorchiidae Stunkard 1921) are a group of flukes that inhabit the circulatory system of turtles. Infection by members of the family Spirorchiidae involves egg deposition in the host bloodstream and accumulation in tissues, which cause inflammatory reactions and embolisms, leading or contributing to the death of the host. Reports of spirorchiid egg lesions in loggerhead turtles (Caretta caretta Linnaeus, 1758) have only been reported from U.S. hosts. In the present report a female loggerhead sea turtle was found dead on the beach in the north part of the State of Rio de Janeiro, Brazil. During gross necropsy, no parasite egg nodule was found. But the microscopic analysis revealed a mild granulomatous inflammatory process due to eggs from the family Spirorchiidae and both Langhans giant cells and foreign-body giant cells in the heart, kidneys, intestines, lungs, and spleen. The present note is the first record of tissue lesions due to spirorchiid eggs in a loggerhead sea turtle outside the United States.

Parasitic Ulcerous Caseous Gastroesophagitis Associated with Rameshwarotrema uterocrescens Rao, 1975 (Digenea: Pronocephalidae) in a Juvenile Green Turtle (Chelonia mydas, Linnaeus 1758 [Testudines: Cheloniidae]): A Case Report

Abstract Here we report a case of ulcerative caseous gastroesophagitis associated with Rameshwarotrema uterocrescens, Rao, 1975 (Digenea: Pronocephalidae), in a juvenile green turtle (Chelonia mydas) from southern Brazil. Similar pathologies have been reported only in adult green turtles from Costa Rica. This paper presents the second report of parasitic esophagitis due to R. uterocrescens and the first occurrence in juvenile green turtles along coastal Brazil.

First report of kidney lesions due to Renicola sp. (Digenea: Trematoda) in free living Magellanic penguins (Spheniscus magellanicus Forster, 1781) found on the coast of Brazil.

Abstract This paper presents the first report of parasites from the genus Renicola sp. in the kidneys of Magellanic penguins. The histological analysis revealed inflammatory infiltrate (eonsinophils, lymphocytes, and plasmocytes), together with fibroplasia and compression of the adjacent ducts.