Mollusks: how are they arranged in the rocky intertidal zone?

Mollusks occupy different kinds of environments, including the intertidal zone. The present study investigated the spatial distribution of mollusks on beach rocks of the intertidal zone of Pacheco Beach in the state of Ceará, Brazil. Sampling occurred from August 2006 to September 2007. Across two transects, six samples of 0.25 m² were collected monthly in gaps of 30 m (0 m, 30 m, 60 m, 90 m, 120 m and 150 m). The mollusks were counted in field, and samples of sediment and algae were taken for further analysis. A total of 74,515 individuals were found and classified into 67 species, 52 genera and 39 families. Gastropods were predominant, corresponding to 73.1% of the species, followed by bivalves (22.4%) and chitons (4.5%). Caecum ryssotitum de Folin, 1867 was the most abundant taxon, representing 68.8% of total specimen findings. In general, species were mostly found in Middle Littoral zone (samples 60 m and 90 m), suggesting that the greater number of microenvironments available in this area may contribute to establishment and survival.

Influence of seasonal changes in daily activity and annual life cycle of Geotrigona mombuca (Hymenoptera, Apidae) in a Cerrado habitat, São Paulo, Brazil

The foraging activity of Geotrigona mombuca Smith, 1863 was studied under natural conditions aiming to verify the influence of seasonal changes on daily flight activity and annual cycle of the colony. Daily flight activity was monitored for a year based on the observation and counting of foragers leaving and entering the hive, as well as the kind of material transported and meteorological factors such as day time, temperature and relative humidity. The influence of seasonal changes was evidenced by alterations on daily rhythm of flight activity and by differences on transportation of food resources, building material and garbage. These data indicate that forager behavior is related to daily microclimate conditions and it is synchronized with the requirements of colony annual cycle, which determines an intense pollen collection in the summer. Thus, the recomposition of the intranidal population in spring and summer can be ensured, which is characterized both for a higher intensity of flight activity and increase in garbage and resin transport, as well as the swarming process in the spring. In this way, an action targeting the preservation or management of the species in a natural environment should consider that survival and reproduction of the colony depends greatly on the amount of available pollen in late winter.

Cephalopoda as prey of juvenile Southern elephant seals at Isla 25 de Mayo/King George, South Shetland Islands

The aim of the present study was to enhance the knowledge of the feeding habits of the juvenile component of the population of Southern elephant seals [Mirounga leonina (Linnaeus, 1758)] from Isla 25 de Mayo, South Shetland Islands, age class whose diet information is scarce. A total of 60 individuals were stomach lavaged in the spring - summer seasons of three consecutive years (2003, 2004 and 2005) of which 53.3 % (n = 32) presented food remnants. The Antarctic glacial squid Psychroteuthis glacialis Thiele, 1921 was the dominant prey taxon in terms of frequency of occurrence (68.7%), numerical abundance (60.1%) and biomass (51.5%), contributing 84.1% to the total relative importance index. Other squid prey species of importance were Slosarczykovia circumantartica Lipinski, 2001 in terms of occurrence (37.5%) and numerical abundance (14%) and Moroteuthis knipovitchi Filippova, 1972 in terms of biomass (16%). All identified cephalopod prey taxa are distributed south of the Antarctic Polar Front, except for the squid Martialia hyadesi Rochebrune & Mabille, 1889 which has a circumpolar distribution associated to the Polar Frontal Zone. No significant differences in the sizes of P. glacialis preyed upon by elephant seals were found between sexes and years. However, significant interannual differences were found in the taxonomical composition of their diet. This would be associated with temporal changes in food availability at the foraging areas of seals, which in turn may have been influenced by changes in oceanographic conditions as a result of the El Niño Southern Oscillation (ENSO) phenomenon that occurred during part of the study period. Furthermore, a differential response of males and females to this temporal variation was observed, with the former being also associated to a predation on octopods. This would suggest a sexual segregation in foraging habits of this species from the early stages of its life cycle.

Composition and ecological patterns of snake assemblages in an Amazon-Cerrado Transition Zone in Brazil

ABSTRACT The present study encompasses the species composition and ecological characteristics of the snake community in a Cerrado-Amazon transition zone in Midwest of Brazil (state of Mato Grosso). The data were collected during six excursions to the "Tanguro" (study area) by visual encounter survey, pitfall traps with drift fences and non-systematic sampling. We collected 194 specimens, distributed in 34 species, 26 genera, and eight families. The most abundant species were Crotalus durissus Linnaeus, 1758 (n = 50), Philodryas olfersii (Lichtenstein, 1823) (n = 15), Philodryas nattereri Steindachner, 1870 (n = 13), Xenodon rabdocephalus (Wied, 1824) (n = 12), Lachesis muta (Linnaeus, 1766) (n = 10) and Erythrolamprus almadensis (Wagler, 1824) (n = 10). The composition of species found here represents a combination of Cerrado and Amazonian savanna fauna.

Climate and land-use changes effects on the distribution of a regional endemism: Melanophryniscus sanmartini (Amphibia, Bufonidae)

ABSTRACT Amphibians are the most threatened vertebrate group according to the IUCN. Land-use and land cover change (LULCC) and climate change (CC) are two of the main factors related to declining amphibian populations. Given the vulnerability of threatened and rare species, the study of their response to these impacts is a conservation priority. The aim of this work was to analyze the combined impact of LULCC and CC on the regionally endemic species Melanophryniscus sanmartini Klappenbach, 1968. This species is currently categorized as near threatened by the IUCN, and previous studies suggest negative effects of projected changes in climate. Using maximum entropy methods we modeled the effects of CC on the current and mid-century distribution of M. sanmartini under two IPCC scenarios - A2 (severe) and B2 (moderate). The effects of LULCC were studied by superimposing the potential distribution with current land use, while future distribution models were evaluated under the scenario of maximum expansion of soybean and afforestation in Uruguay. The results suggest that M. sanmartini is distributed in eastern Uruguay and the south of Brazil, mainly related to hilly and grasslands systems. Currently more than 10% of this species' distribution is superimposed by agricultural crops and exotic forest plantations. Contrasting with a recent modelling study our models suggest an expansion of the distribution of M. sanmartini by mid-century under both climate scenarios. However, despite the rise in climatically suitable areas for the species in the future, LULCC projections indicate that the proportion of modified habitats will occupy up to 25% of the distribution of M. sanmartini. Future change in climate conditions could represent an opportunity for M. sanmartini, but management measures are needed to mitigate the effects of habitat modification in order to ensure its survival and allow the eventual expansion of its distribution.

Lesões microscopicas do baço na purpura trombocitopenica idiopatica

Histopathological changes strikingly similar were found in the spleen of four cases (young female subjects) of idiopathic thrombocytopenic purpura hemorrhagica in which splenectomy was performed. The chief changes reported are enlargement of the marginal zone of the malpighian corpuscles, proliferation and mobilization of the reticulo-endothelial cells, myeloid metaplasia, local (tissue) eosinophilia, and stoppage of the circulation or stasis of platelets from which results a filling of the spelenic sinuses by such elements. The latter phenomenon will possibly present some bearing with thrombocytopenia which is such a characteristic feature in this disease and will perhaps account for the rapid increase in blood platelets which usually follows splenectomy and or the finding of increased megakaryocytes in the bone marrow.

A study of the endocervical columnar cells II - effects of physiological changes and of oathological lesions of the uterus on the specific numerical composition of the endocervical epithelium

In the second part of this paper we nalysed the correlation between the clinical pathological alterations and the sum of the types of columnar cells of 300 histological sections of cervix. Fifty histological sections of normal cervix of sexually mature women were selected and considered as normal in pattern. The specific counts of the columnar cells which line the endocervical mucosa and those of the glands of 50 normal cervices were compared with other similar counts made in 50 histological sections of cervices of old women and emphasized the differences. Comparisons were made also between 50 normal cervices and 50 sections of cervices with chronic inflammation, 50 cervices with epidermoid metaplasia and 50 cervices with myoma of the corpus. Counts were made from 50 cervices of patients who on the occasion of the surgical operation were in the proliferative phase of the menstrual cycle; these were compared with the counts of 50 cervices of uteri in the luteal phase. Finally, the numerical frequency of the following data encountered in the 300 cervices was recorded: 1. aspects of the ectocervical epithelium; 2. number of Nabothian cysts; 3. number of cervical glands; 5. number of deliveries and 6. aspect of the material within the cervical canal.

Hematological changes in mice experimentally infected with Trypanosoma Cruzi

Mice inoculated with trypanosoma cruzi display an intense thrombocytopenia which is more severe in animals infected with the Y than CL strain. In animals inoculated with a T. cruzi strain which induces chronic infection (Colombiana), the number of platelets decreases as parasitemia ascends, and then reverts to normal values as soon as the acute infection merges into the chronic phase. The mechanisms involved in the thrombocytopenia are still obscure and are likely to be related to more general phenomena affecting the host rather than to direct damage of platelets or precursor cells by parasitism. Anemia and leukopenia are also present in T. cruzi infected mice.

Mitochondrial ultrastructural and atpase changes during the life cycle of Ascaris Suum

Ultrastructural morphology and ATPase specific activities of mitochondria isolated from 1-celled fertilized egg, 10-day embryo, 21-day infective larvae and adult body wall muscle of Ascaris suum and rat liver were determined and compared. Although cristae of both muscle and egg mitochondria contained numerous elementary particles with head pieces of conventional diameter (85 A), each muscle mitochondrion contained relatively few, short cristae with a diminished frequency of elementary particles and associated ATPase activity. These morphological relationships are related to the previous conclusion that the transition from an aerobic to an essentially anaerobic metabolism is intimately associated with the mitochondrion and is a normal and mandatory feature of development.

Comparison of pathologic changes in mammalian hosts infected with Schistosoma mansoni, S. japonicum and S. haematobium

The hepatic, intestinal and cardiopulmonary lesions produced by Schistosoma mansoni, S. haematobium and S. japonicum in man and experimental animals often bear striking similarities but usually have distinctive features as well. These are often related to parasitologic differences. Thus S. japonicum and S. haematobium lay their eggs in clusters which elicit the formation of large composite granulomas. The worms of these two species also tend to be sedentary, remaining in a single location for prolonged periods, thus producing large focal lesions in the intestines or urinary tract. Worm pairs of these two species also are gregarious and many worm pairs are often found in a single lesion. The size of circumoval granulomas, and the degree of fibrosis, are T cell dependent. The modulation of granuloma size is largely T cell dependent in mice infected with S. mansoni but is mostly regulated by serum factors in S. japonicum infected mice. In spite of these differences in egg laying and immunoregulation both S. mansoni and S. japonicum produce Symmers' fibrosis in the chimpanzee while S. haematobium does not, despite the presence of numerous eggs in the liver.

Trypanosoma cruzi: metacyclogenesis in vitro - I. Changes in the properties of metacyclic trypomastigotes maintained in the laboratory by different methods

In this work we have studied the modifications in the biological properties of Trypanosoma cruzi when the parasite is maintained for a long time in axenic culture. The studies were done with a clone from an avirulent strain (Dm30L) and a non-cloned virulent strain (EP) of T. cruzi. Both parasiteswere maintained, for at least three years, by successive triatomine/mouse alternate passage (control condition), or by serial passage in axenic medium (culture condition), or only in the mouse (mouse condition). The comparison between parasites of culture and control condition showed that metacyclogenesis capacity was reduced in the former and that the resulting metacyclics displayed an attenuatedvirulence. In order to compare the virulence of metacyclics from the urine of the insect vector, Rhodnius prolixus were infected by artificial feeding with parasites of the control or culture condition. After three triatomine/triatomine passages, there was observed an almost identical biological behavior for these parasites, hence indicating that the maintenance of T. cruzi for a long time in axenic culture affects the differentiation capacity and the virulence of the parasite. Additionally, it was demonstrated that it is possible to maintain T. cruzi exclusively through passages in the invertebrate host.

Host-induced morphological changes of Schistosoma mansoni Sambon, 1907 male worms

In order to evaluate the permissiveness of Nectomys squamipes to Schistosoma mansoni and the influence of the albino mice on the morphological aspects of adult worms derived from a population isolated from N. squamipes, the morphology of adult S. mansoni Sambon, 1907 male worms was studied using a digital image analyser (MOP VIDEOPLAN) and light microscopy. Their sources were as follows: (1) recovered from the wild rodent N. squamipes Brants naturally infected from Sumidouro, RJ, Brazil; (2) recovered from albino mice experimentally infected with the strain derived from N. squamipes; (3) recovered after the isolation of a strain derived from aboriginal human infections in Sumidouro. Worms recovered from N. squamipes (group 1) showed body lenght and distance between suckers significantly bigger than those of the specimens maintained in mice (groups 2 and 3). The number of tests in group 1 was statistically less than of groups 2 and 3. Group 2 strains which were maintained in mice, presented the lenght of the worms as the only significant different character. Data show that: (1) N. squamipes is a more suitable host for the development of S. mansoni when compared to the albino mice; (2) a strain of S. mansoni isolated from a natural host undergoes morphological changes after its passage in the white mouse.

Hemagglutinating and fusogenic activities of Newcastle disease virus: studies on receptor binding specificity and pH-induced conformational changes

Vaccinal and wild strains of Newcastle Disease virus (NDV) were analyzed for cell receptor binding and fusogenic biological properties associated with their HN (hemagglutinin-neuraminidase) and F (fusion protein) surface structures respectively. The evaluation of the biological activities of HN and F was carried out respectively by determination of hemagglutinating titers and hemolysis percentages, using erythrocytes from various animal origins at different pH values. Significant differences in hemagglutination titers for some strains of NDV were detected, when interacting with goose, sheep, guinea-pip and human "O" group erythrocytes at neutral pH. Diversity of hemolysis percentagens was observed between different NDV strains at acid pH. These analysis were developed to evaluate particular aspects of the actual influence of the receptor specifity and pH on the receptor binding and fusogenic processes of Newcastle Disease viruses.

Onchocerciasis in Ecuador: changes in prevalence of ocular lesions in Onchocerca volvulus infected individuals over the period 1980-1990

Trends in prevalence rates of onchocercal ocular lesions were examined over the period 1980 to 1990 using data from two cross-sectional surveys. There was evidence for increasing prevalence of anterior chamber microfilariae, iridocyclitis, optic atrophy, and chorioretinopathy. Large increases in prevalence, in particular, were seen for posterior segment lesions: optic atrophy increased from 2.7% to 6.4% and chorioretinopathy from 8.8% to 35.6%. Greatest increases in these lesions were seen in the Chachi which was attributed to the large increases in prevalence of microfilariae in the anterior chamber particularly in those aged 30 years or greater. The study findings suggest that ocular onchocerciasis is evolving in parallel with the well documented parasitological changes.

Fecundity Changes Induced by Low-Doses of Gamma Radiation on Biomphalaria straminea (Dunker, 1848)

A population of 420 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, received gamma-rays obtained from a 60Co source in low-doses (0/2,5/5/7,5/10/15/20 and 25 Gy); half population was kept in colonies (allowing cross fertilization) and the other half was mantained in sexual isolation (allowing self fertilization). Results showed that 15 Gy stimulates the fertility of both groups but the colonies were more sensitive and at this dose its fertility overpasses the control group dose. The possible hormonal role played in the observed phenomena is under investigation