Lymphadenitis,trans-epidermal elimination and unusualhistopathology in human rhinosporidiosis

From a study of rhinosporidial tissues of 64 human cases of ocular, urethral and nasopharyngeal disease, unusual histopathological features of 27 cases are described. Histopathological evidence of lymphadenitis in rhinosporidiosis is presented for the first time. The phenomenon of `trans-epidermal elimination' of sporangia of the causative pathogen Rhinosporidium seeberi is illustrated and it is argued that this phenomenon is rather the pathogen's mechanism for endospore-dispersal than a non-specific defence reaction of the host as has previously been suggested. Other unusual appearances described include variations in the intensity and composition of the host-cell infiltrate in tissues from different patients and in different portions of the same tissue, pitfalls in histopathological diagnosis, and unusual appearances of the pathogen. Histopathological clues to the pathogenesis of rhinosporidiosis and mechanisms of anti-rhinosporidial immunity in the host are discussed, illustrating the probable occurrence of immunesuppressive reactions to account for the variations in the density and composition of the host-cell infiltrate and the state of the rhinosporidial sporangia – intact or degenerate –, relating these variations to the chronicity, recurrences and systemic dissemination of rhinosporidiosis. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro studies on the mechanisms of endospore release by Rhinosporidium seeberi

Studies of Rhinosporidium seeberi have demonstrated that this organism has a complex life cycle in infected tissues. Its in vivo life cycle is initiated with the release of endospores into a host's tissues from its spherical sporangia. However, little is known about the mechanisms of sporangium formation and endospore release since this pathogen is intractable to culture. We have studied the in vitro mechanisms of endospore release from viable R. seeberi's sporangia. It was found that watery substances visibly stimulates the mature sporangia of R. seeberi to the point of endospore discharge. The internal rearrangement of the endospores within the mature sporangia, the opening of an apical pore in R. seeberi's cell wall, and the active release of the endospores were the main features of this process. Only one pore per sporangium was observed. The finding of early stages of pore development in juvenile and intermediate sporangia suggested that its formation is genetically programed and that it is not a random process. The stimulation of R. seeberi's sporangia by water supports the epidemiological studies that had linked this pathogen with wet environments. It also explains, in part, its affinities for mucous membranes in infected hosts. The microscopic features of endospore discharge suggest a connection with organisms classified in the Kingdom Protoctista. This study strongly supports a recent finding that placed R. seeberi with organisms in the protoctistan Mesomycetozoa clade. This revised version was published online in June 2006 with corrections to the Cover Date.     

A simple filtration device for separating nonadherent microorganisms from mammalian cells in in vitro studies on microbial adherence

In adherence studies, the removal of nonadherent microorganisms is essential for the valid enumeration of microorganisms that adhere to host cells. Although filtration devices are available commercially for the removal of nonadherent microorganisms, these are expensive and not reusable. In this article, we describe a simple, inexpensive, and reusable filtration device composed of two chambers of nylon, a nylon membrane of desired pore size, a rubber washer, and supporting stainless steel mesh. The device was effective in in vitro adherence assays for removing nonadherent endospores of Rhinosporidium seeberi from human buccal epithelial cells, providing valid counts of adherent microorganisms.     

Cell-mediated immune responses (CMIR) to Rhinosporidium seeberi in mice

There is no published data on Cell Mediated Immune Responses in experimental animals to Rhinosporidium seeberi the causative agent of human and animal rhinosporidiosis. The quantitative mouse foot-pad model was used to assay the Delayed-Type Hypersensitivity (DTH) cell-mediated immune response to extracts of purified endospores and sporangia of R. seeberi. Histological examination was used to confirm that the foot-pad reactions were compatible with DTH reactions in the mouse. We report that sonically disintegrated rhinosporidial endospores/sporangia induced DTH responses in the foot-pads of sensitized mice which were comparable in intensity and histological profile to that induced by sheep red blood cells in SRBC sensitized mice. Anti-rhinosporidial antibody was also induced. Filtrates of the soluble antigens in sonicated suspensions failed to evoke a DTH-foot-pad (DTH-FP) response in sensitized mice although an anti-rhinosporidial antibody response to this preparation was detected. Prolonged pre-treatment with sonicated suspensions of endospores and sporangia resulted in a decrease of DTH reactivity as compared with reactions following pre-treatment of a shorter duration. This revised version was published online in June 2006 with corrections to the Cover Date.     

Rhinosporidium seeberi: Light,phase contrast,fluorescent and scanning electron microscopic study

Phase contrast microscopic study indicated the multilayered structure of the sporangial wall of R. seeberi while the scanning electronmicroscopic study revealed a trilaminated wall compared to a thick double walled light microscopic structure. The scanning electronmicroscopy revealed the spores of varying sizes which were found either discretely or in groups interconnected and seen attached to the inner aspect of the sporangial wall. Autofluorescence of sporangia and spores was observed under microscope. Acridine orange staining revealed the presence of DNA materials in the spore and sporangia.     

Ecological distribution of the shrimp Pleoticus muelleri (Bate, 1888) (Decapoda: Penaeoidea) in southeastern Brazil

The abundance and ecological distribution of the shrimp Pleoticus muelleri as a function of certain environmental factors were investigated from January 1998 through December 1999 in the region of Ubatuba, São Paulo, Brazil. The collections were made monthly in the bays of Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV). Each bay was divided into six sampling transects, four transects parallel to the shoreline and two near the rocky shores on the opposite side. We employed a commercial shrimp boat equipped with two double-rig nets. A total of 6252 shrimp were collected, including 3321 from MV, 1467 from UBM, and 1464 from UBA. Most of the shrimp were caught in the deeper, higher-salinity areas. The high abundance of P. muelleri observed in the southern part of the region studied was related to a sediments with a higher percentage of silt and clay. The numbers of P. muelleri were positively correlated with periods of cooler temperatures. Thus, temperature and the type of sediment were determinant factors in the distribution of P. muelleri in this region.     

Distribution and seasonal dynamics of Rhodophyta in the Preto River basin,southeastern Brazil

Distribution and seasonal dynamics of freshwater Rhodophyta were investigated in the Preto River basin, located in northwestern São Paulo State, southeastern Brazil. Twenty-two sites were sampled, six monthly during one year, four bimonthly during two years, and 12 twice (hot-rainy and cool-dry seasons) during the study period (May 1989 through March 1991). Red algal representatives were found in 19 sites (86.4%). Four species occurred in the basin with varying frequencies:Batrachospermum delicatulum (54.5%),Compsopogon coeruleus (36.4%),B. bicudoi (13.6%) andB. virgatum (4.5%). In addition, Chantransia stage of the batrachospermalean species was found in 17 sites (77.3%).B. bicudoi, B. virgatum andC. coeruleus occurred only in large stream segments ( 3-order), generally in the main river, whereasB. delicatulum was more frequent in small streams ( 3-order). The stream variables most closely related to the species distribution in the basin were specific conductance, pH and oxygen.B. bicudoi andB. delicatulum showed a marked seasonality: gametophytes were observed from late fall to early spring, while the Chantransia stage generally occurred throughout the year.C. coeruleus was observed throughout the year in most sites, but the populations were generally more abundant from late fall to early spring. The combination of lower temperature and reduced turbidity resulting in increased illumination to the benthic algae during the dry winter months promotes the gametophytic growth of the batrachospermalean species, whereas current velocity was found to be the most influential stream variable forC. coeruleus. The persistance of the Chantransia stage throughout the year as well as its tolerance to wider environmental conditions are key factors in the efficiency of the batrachospermalean life history strategy in lotic ecosystems.     

Beetle pollination and flowering rhythm ofAnnona spp. (Annonaceae) in Brazil

Dynastid scarab beetles are the main or exclusive pollinators ofAnnona spp. with large flowers and wide floral chambers. These nocturnal beetles are attracted by the characteristic odours which are caused by measurable temperature elevation of the flowers up to 10°C or even 15°C above the ambient air temperature. TheAnnona spp. investigated showed different floral rhythms varying from one to three days. The elaborate and wellcoordinated flowering processes, along with floral heating and olfactorial attraction of the night-activeCyclocephala spp., result in a very precise and effective pollination. The floral chamber provides alimentation for the beetles in the form of nutritious food-tissues and pollen and offers a mating place and a well developed shelter against predation and environmental changes. A staggered flowering period and an alternative attraction of different beetle species seems to be more a device for diminishing competition between the cooccurringAnnona spp. than a hybridization barrier.     

Biological control of plant pathogens in Brazil: application and current research

There are several examples of successful isolation, selection and development of antagonists of plant pathogens available for commercial use: mild strains of Tristeza virus of citrus for the control of Tristeza virus of citrus through preimmunization; Acremonium alternatum and A. persicinum for the control of tar spot of coconut (Catacauma torrendiella and Coccostroma palmicola); Trichoderma spp. for the control of Phytophthora cactorum on apple after soil treatment with formaldehyde and Dicyma pulvinata for the control of South American leaf blight (Microcyclus ulei) on rubber trees (Hevea brasiliensis) associated with polyclone plantations, are just a few. In an advanced stage of development there are for example: Bacillus subtilis for seed treatment and control of Sphaerotheca fuliginea on zucchini squash; Trichoderma spp. for soilborne pathogens; and Gliocladium roseum for the control of Botrytis cinerea in greenhouse cultivated strawberry.The author is with EMBRAPA/CNPMA, C.P. 69, 13820-000, Jaguariúna, SP-Brazil     

Dilleniaceae Novae Neotropicae VIII. Two new species of Davilla from Brazil

Two new species of the genusDavilla from Brazil are described and illustrated (D. kubitzkii andD. morri). The new species are assigned to sect.Homalochlaena and their relationships with allied species are discussed.     

Rhinosporidiosis in man: Case reports

Three cases of rhinosporidiosis with complications, hitherto not reported, are presented. Frog-faced deformity and seizures were observed in one case, excessive bleeding, loss of olfactory sensation and septal perforation were noticed in the second case, while the third one exhibited a disseminated type of the disease. Clinical findings of these cases are discussed.     

Genetics of Brazil nut (Bertholletia excelsa Humb. & Bonpl.: Lecythidaceae)

Summary We provide an estimate of genetic variation within and between two populations of Bertholletia excelsa (Brazil nut), a large canopy tree found in the rain forests of South America. Average heterozygosity is 0.190, and 54.3% of the sampled loci are polymorphic. The population structure deviates significantly from Hardy-Weinberg expectations for Fest2 and Pgm2 (F =0.405 and 0.443, respectively) in one population, and highly significantly (F=-0.341) for Gdh in the other population. Although allele frequencies of the two populations differ significantly for Aat2, Est5, Mdh1, and Mdh2B, Nei's coefficient of gene differentiation (G_st) indicates that the between-population component (D_st) of genic diversity represents only 3.75% of the size of the within-population component (H_s). The implications of these findings in terms of conservation genetics are that much of the genetic diversity of this species may be preserved within one or a few populations. However, such populations must be very large because it appears that the large amount of genetic variation in Brazil nut populations is maintained by extensive gene flow and bonds of mating over a large area. The genetic architecture of Bertholletia excelsa is similar to that expected for an extensively diploidized paleopolyploid species.     

Temperature-related effects of three insects on growth ofSalvinia molesta in Brazil

The effect ofCyrtobagous salviniae, Samea multiplicalis, andPaulinia acuminata on the growth ofSalvinia molesta was assessed in relation to temperature in field cages at 2 sites in Brazil, a canal with running-water and a lagoon with stillwater. Each insect species reduced the growth ofS. molesta over a mean leaftemperature range of 16–30°C, causing more damage as temperature increased. There was no difference between the 3 species in response to temperature. These results and their implication to the performance of these insects as biological control agents againstS. molesta are discussed.

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Résumé L'effet deCyrtobagous salviniae, deSamea multiplicalis et dePaulinia acuminata sur la croissance deSalvinia molesta a été étudié en relation avec la température dans des cages implantées dans 2 situations au Brésil, un canal avec de l'eau courante et une lagune avec de l'eau stagnante. Chaque espèce réduit la croissance deS. molesta dans une gamme de températures des feuilles s'étendant de 16° à 30°C, les dégats augmentent avec l'accroissement de la température. Il n'y a pas de différence entre les 3 espèces vis-à-vis de leur réaction à la température. Ces résultats et leur implication quant au rendement de ces insectes comme agents biologiques de lutte contreS. molesta sont discutés.

     

Renewed hope for the threatened avian endemics of northeastern Brazil

The forests north of the São Francisco River, in northeastern Brazil, conform a centre of endemism for plants and animals. Currently only 5% of its original forest cover is left, following 500 years of human colonisation. Avian endemism is high, and during the 1980s four birds were described from these forests, Alagoas Foliage-gleaner Philydor novaesi, Orange-bellied Antwren Terenura sicki, Alagoas Antwren Myrmotherula snowi and Alagoas Tyrannulet Phylloscartes ceciliae. Their type locality, Murici Ecological Station, in the coastal mountains of Alagoas state, was the only site where the four species were known to occur together, and became the focus of much attention from conservation organisations. We here report on recent surveys at Reserva Privada do Patrimônio Natural Frei Caneca, in the mountains of Pernambuco state, which found these 4 species and 27 other threatened and endemic birds, and a yet undescribed taxon. We propose that more thorough surveys are needed in the reserve and its vicinity, to locate fragments of suitable forest for these species. These should be regarded within a management plan for the reserve (including research and monitoring), and such work should be expanded to a regional level. An educational programme focusing on the values of these forests and the negative impacts of human activities is needed very much.     

Marine Ornamental Trade in Brazil

Brazil is one of the five leading exporting countries of tropical aquarium fishes in the world, and the interest in marine ornamental organisms has increased substantially there from the mid to the late 1990s. About 120 reef fish species are currently harvested in Brazil's ornamental trade. Among the 75 most harvested species, 26 (34.7%) are endemic, eight (10.7%) are rare, and six (8.2%) are estuarine-dependent species. Fifty-five species (75.3%) have complex reproductive strategies and/or parental care. In quantitative terms, the top 10 species comprises 62% of the species exported from Brazil to the USA and the European Community. The most harvested reef invertebrates include about 65 species. The most representative groups are crustaceans with 15 species (23%), and molluscs and stony corals with 10 species (15.4%) each. Among these, 15 (23%) are endemics, nine (13.8%) are rare species, and seven (10.8%) are important reef builders. A case of local extinction of the giant anemone Condylactis gigantea is reported. To alleviate ecological impacts a series of urgent measures is suggested, including the creation of specific laws for marine ornamental harvesting and improving law enforcement to prevent illegal trade in Brazil.     

Two new species of Hippocrateaceae from Brazil

Two new species of Hippocrateaceae from Brazil are described and illustrated:Pristimera sclerophylla Lombardi, the one species of the genus that occurs in the xerophytic vegetation of northeastern Brazil, andCheiloclinium puberulum Lombardi, a species with puberulent inflorescences from the rain forests of the Amazon basin.