181 resultados para Giganteus


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Although bats of the genus Pteropus are important ecologically as pollinators and natural hosts for zoonotic pathogens, little is known about their basic physiology. Hematology and plasma biochemistries were determined from wild-caught flying foxes (Pteropus giganteus) in northern India (n = 41). Mean lymphocyte differential count was higher for juveniles than adults. Mean platelet count was lower than previously reported. No hemoparasites were observed. No differences were observed between plasma biochemistry values of male and female bats, juveniles and adults, or lactating and nonlactating females. Variation in aspartate aminotransferase (AST) was seen based on body condition score. Blood urea nitrogen and cholesterol concentrations were lower in P. giganteus than other mammalian groups, but were consistent with those reported from other Pteropus species. Alanine aminotransferase and AST concentrations were higher than those reported for Pteropus vampyrus, a closely related species. This study provides basic physiologic information that can be used in future health and disease studies of Indian flying foxes.

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Reductive acetogenesis is an alternative to methanogenesis for removing hydrogen produced during enteric fermentation. In Australia, kangaroos have evolved an enlarged forestomach analogous to the rumen of sheep and cattle. However, unlike sheep and cattle, kangaroos produce very little methane from enteric fermentation. From samples of gut contents from five eastern grey and three red kangaroos, we were not able to detect methanogens using a PCR protocol, but did detect the formyltetrahydrofolate synthetase (FTHFS) gene (likely to be used for reductive acetogenesis) in all animals. Isolations to recover acetogens resulted in two different classes of hydrogen consuming bacteria being isolated. The first class consisted of acetogens that possessed the FTHFS gene, which except for Clostridium glycolicum, were not closely related to any previously cultured bacteria. The second class were not acetogens but consisted of enterobacteria (Escherichia coli and Shigella) that did not possess FTHFS genes but did utilise hydrogen and produce acetate. Enumeration of the acetogens containing the FTHFS gene by real-time PCR indicated that bacteria of the taxa designated YE257 were common to all the kangaroos whereas YE266/YE273 were only detected in eastern grey kangaroos. When present, both species occurred at densities above *106 cell equivalents per mL. C. glycolicum was not detected in the kangaroos and, unlike YE257 and YE266/273, is unlikely to play a major role in reductive acetogenesis in the foregut of kangaroos.

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The roles and epidemiological features of tick-borne protozoans are not well elicited in wildlife. Babesia spp. are documented in many domestic animals, including cattle, horses, pigs, dogs and cats. Three cases affecting eastern grey kangaroos are described. The kangaroos exhibited neurological signs, depression and marked anaemia, and microscopic examination of blood smears revealed intraerythrocytic piroplasms. One to seven intraerythrocytic spherical, oval, pyriform and irregularly-shaped parasites consistent with Babesia spp. were seen in the blood smears and the percentage of infected erythrocytes was estimated to be approximately 7% in each case. Data suggest that the tick vector for this kangaroo Babesia sp. is a Haemaphysalis species. For Case 2, ultrastructural examination of the erythrocytes of the renal capillaries showed parasites resembling Babesia spp. and 18 of 33 erythrocytes were infected. DNA sequencing of the amplified 18S rDNA confirmed that the observed intraerythrocytic piroplasms belong to the genus Babesia. The phylogenetic position of this new kangaroo Babesia sp. (de novo Babesia macropus), as a sister species to the new Australian woylie Babesia sp., suggests a close affinity to the described Afro-Eurasian species Babesia orientalis and Babesia occultans suggesting perhaps a common ancestor for the Babesia in kangaroos. © 2012 Australian Society for Parasitology.

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This is a retrospective study of 38 cases of infection by Babesia macropus, associated with a syndrome of anaemia and debility in hand-reared or free-ranging juvenile eastern grey kangaroos (Macropus giganteus) from coastal New South Wales and south-eastern Queensland between 1995 and 2013. Infection with B. macropus is recorded for the first time in agile wallabies (Macropus agilis) from far north Queensland. Animals in which B. macropus infection was considered to be the primary cause of morbidity had marked anaemia, lethargy and neurological signs, and often died. In these cases, parasitised erythrocytes were few or undetectable in peripheral blood samples but were sequestered in large numbers within small vessels of visceral organs, particularly in the kidney and brain, associated with distinctive clusters of extraerythrocytic organisms. Initial identification of this piroplasm in peripheral blood smears and in tissue impression smears and histological sections was confirmed using transmission electron microscopy and molecular analysis. Samples of kidney, brain or blood were tested using PCR and DNA sequencing of the 18S ribosomal RNA and heat shock protein 70 gene using primers specific for piroplasms. The piroplasm detected in these samples had 100 sequence identity in the 18S rRNA region with the recently described Babesia macropus in two eastern grey kangaroos from New South Wales and Queensland, and a high degree of similarity to an unnamed Babesia sp. recently detected in three woylies (Bettongia penicillata ogilbyi) in Western Australia.

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We present the complete mitochondrial genome (accession number: LK995454) of an iconic Australian species, the eastern grey kangaroo (Macropus giganteus). The mitogenomic organization is consistent with other marsupials, encoding 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, an origin of light strand replication and a control region or Dloop. No repetitive sequences were detected in the control region. The M. giganteus mitogenome exemplifies a combination of tRNA gene order and structural peculiarities that appear to be unique to marsupials. We present a maximum likelihood phylogeny based on complete mitochondrial protein and RNA coding sequences that confirms the phylogenetic position of the grey kangaroo among macropodids.

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In southeastern Australia ecological burning is frequently used to maintain a number of plant and animal populations. However, many of these prescribed fires are small, and may focus intense grazing activity on new regrowth. At Reef Hills Regional Park, Victoria shrub species have senesced, presumably due to the absence of fire. Ecological burning may be necessary to promote regeneration, however, the population density of the Eastern Grey Kangaroo (Macropus giganteus) is high (approx 38 per km2), and grazing pressure presents a significant risk to postfire vegetation recovery. An assessment of grazing patterns and their effects on postfire recovery was carried out at Reef Hills Regional Park through grazing exclusion plots. Preferential grazing by Eastern Grey Kangaroos occurred on small burnt plots compared to adjacent unburnt areas as determined by faecal pellet counts. On burnt areas, there was a significant reduction in shrub diversity on grazed plots compared to ungrazed plots. Most observations of kangaroos were of animals grazing on farmland surrounding the Park, and it is likely that any burning might shift grazing from farmland to burnt areas when new growth occurs. This needs to be considered before any ecological burn plan is applied to manage vegetation communities, particularly if the plan requires small areas to be burnt. We recommended that a large area up to 200 ha area be burnt and monitored to determine whether burning larger areas disperses grazing pressure from macropods to a level where impacts on vegetation are reduced and localized plant extinctions do not occur.

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An Aspergillus giganteus strain was isolated as an excellent producer of xylanase associated with low levels of cellulase. Optimal xylanase production was obtained in liquid VOGEL medium containing xylan as carbon source, pH 6.5 to 7.0, at 25degreesC and. under shaking at 120 rpm during 84h. Among the several carbon sources tested, higher xylanase production was verified in xylan, xylose, sugar-cane bagasse, wheat bran and corn cob cultures, respectively. Optimal conditions for activity determination were 50degreesC and pH 6.0. The xylanolytic complex of A. giganteus showed low thermal stability with T-50 of 2 h, 13 min and I min when it was incubated at 40, 50 and 60degreesC, respectively, and high stability from pH 4.5 to 10.5, with the best interval between 7.0 to 7.5. This broad range of stability in alkali pH indicates a potential applicability in some industrial processes, which require such condition. Xylanolytic activity of A. giganteus was totally inhibited by Hg+2, Cu+2 and SDS at 10 mm. The analysis of the products from the oat spelts xylan hydrolysis through thin-layer chromatography indicated endoxylanase activity, lack of debranching enzymes and P-xylosidase activity in assay conditions.

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Polygalacturonases are part of the group of enzymes involved in pectin degradation. The aim of this work was to investigate some of the factors affecting polygalacturonase production by an Aspergillus giganteus strain and to characterize this pectinolytic activity. Several carbon sources, both pure substances and natural substrates, were tested in standing cultures, and the best results were obtained with orange bagasse and purified citrus pectin. on citrus pectin as sole carbon source, the highest extracellular activity (9.5 U/ml and 40.6 U/mg protein) was obtained in 4.5-day-old cultures shaken at 120 rpm, pH 3.5 and 30 degrees C, while on orange bagasse, the highest extracellular activity (48.5 U/ml and 78.3 U/mg protein) was obtained in 3.5-day-old cultures shaken at 120 rpm, pH 6.0 and 30 degrees C. Optimal polygalacturonase activity was observed in assays conducted at pH 5.5-6.5 and 55-60 degrees C. The activity showed good thermal stability, with half-lives of 90 and 30 min when incubated at 55 and 60 degrees C, respectively. High stability was observed from pH 4.5 to 8.5; more than 90% of the activity remained after 24 h in this pH range.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A strain of Aspergillus giganteus cultivated in a medium with xylan produced two xylanases (xylanase I and II) which were purified to homogeneity. Their molar mass, estimated by SDS-PAGE, were 21 and 24 kDa, respectively. Both enzymes are glycoproteins with 50°C temperature optimum; optimum pH was 6.0-6.5 for xylanase I and 6.0 for xylanase II. At 50°C xylanase I exhibited higher thermostability than xylanase II. Hg2+, Cu 2+ and SDS were strong inhibitors, 1,4-dithiothreitol stimulated the reaction of both enzymes. Both xylanases are xylan-specific; kinetic parameters indicated higher efficiency in the hydrolysis of oat spelts xylan. In hydrolysis of this substrate, xylotriose, xylotetraose and larger xylooligosaccharides were released and hence the enzymes were classified as endoxylanases.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)