Littoral decapods of Socorro Island, Revillagigedo Archipelago, Mexico

Decapod community inhabiting the rocky littoral of eight bays from Socorro island, Revillagigedo Archipelago, was studied during March 1992. Samples were collected from one-square meter plots placed following transects drawn perpendicularly to the shoreline along the intertidal zone. Species richness and abundance were determined in each bay, as well as the similarity between bays using Morisita's index. Organisms collected belong to six families, 20 genera and 26 species of the Brachyura and Anomura infraorders. Xanthidae was the family with the highest number of species, and the highest species richness was recorded at the V. Lozano bay. Pachygrapsus transversus, Xanthodius cooksoni and Calcinus explorator were the most abundant species in nearly all localities. Dendrogram obtained define two groups of bays at a similarity level above 0.67, given the similarity in the crab's species richness and their abundance between bays in the island.

Littoral decapods of Socorro Island, Revillagigedo Archipelago, Mexico.

Decapod community inhabiting the rocky littoral of eight bays from Socorro island, Revillagigedo Archipelago, was studied during March 1992. Samples were collected from one-square meter plots placed following transects drawn perpendicularly to the shoreline along the intertidal zone. Species richness and abundance were determined in each bay, as well as the similarity between bays using Morisita's index. Organisms collected belong to six families, 20 genera and 26 species of the Brachyura and Anomura infraorders. Xanthidae was the family with the highest number of species, and the highest species richness was recorded at the V. Lozano bay. Pachygrapsus transversus, Xanthodius cooksoni and Calcinus explorator were the most abundant species in nearly all localities. Dendrogram obtained define two groups of bays at a similarity level above 0.67, given the similarity in the crab's species richness and their abundance between bays in the island.

[Abundance and diversity of littoral invertebrates in the Socorro Island, Revillagigedo Archipelago, Mexico]. / Abundancia y diversidad de los invertebrados litorales de isla Socorro, Archipiélago Revillagigedo, México.

Composition, abundance, diversity and distribution of the littoral benthic invertebrates of Socorro Island with transects (parallel to the coast and with 1 m2 quadrats) were analyzed. During the spring of 1991 and 1992 samples were taken from the upper and middle levels of the intertidal zone in Vargas Lozano, Braithwaite, Blanca SW, Blanca NE, Binners, Grayson, Academia and Norte bays. The 161 species found belong to Porifera, Cnidaria, Platyhelmintha, Nemertina, Sipunculida, Annelida, Mollusca, Anthropoda and Echinodermata. Crustaceans and mollusks were the richest groups in both years, as in other rocky shores. Highest total density was found in Blanca NE bay in both samplings, with 281 orgs./m2 in the first and 172 orgs./m2 in the second. Most frequently found species were Isognomon janus (Mollusca, Pelecypoda), Littorina pullata (Mollusca, Gastropoda), Hipponix panamensis (Mollusca, Gastropoda), Pachygrapsus transversus (Crustacea, Grapsoidea) and Turbo funiculosus (Mollusca, Gastropoda). Because of the complexity of the habitat structure, Vargas Lozano was the bay with the highest specific richness (83 species), greatest diversity (4.7 bits/individual) and lowest dominance (0.065). Most species were classified as accidentals with the Dajoz's frequency classification, while the dominant species were accessories and only I. janus, in the spring 1991, was a constant species. Two kinds of bays were distinguished: those with some dominant species (density) and those in which there was no evident dominance by a particular species. Consequently, the diversity and evenness values were set apart: homogeneous communities (Vargas Lozano and Binners) and heterogeneous communities (Grayson bay and others), characterized by intermediate evenness values. The Jaccard similarity index identified two regions: one formed by bays found mainly in the southwest part of the island (Binners, Vargas Lozano, Braithwaite, Grayson and Blanca SW) and the other found in the northern region that included Blanca NE, Academia and Norte; however, Blanca NE had the most diverse species composition because of its physiographic particularities and because the sediment retained by the filamentous algae on the flat stones allow many species to settle down. Isognomon janus, Mitrella baccata (Mollusca, Gastropoda), P. transversus and Xanthodius cooksoni (Crustacea, Xanthoidea) were the most common species in all bays in both expeditions. The dominance-diversity relationship, the high specific richness and the low dominance of coastal invertebrates from the different bays, are indicative that the communities in Socorro Island are little disturbed; their specific richness are similar to those of coral reefs.

Abundancia y diversidad de los invertebrados litorales de isla Socorro, ArchipiÚlago Revillagigedo, México / Abundance and diversity of littoral invertebrates in the Socorro Island, Revillagigedo Archipelago, Mexico

Composition, abundance, diversity and distribution of the littoral benthic invertebrates of Socorro Island with transects (parallel to the coast and with 1 m2 quadrats) were analyzed. During the spring of 1991 and 1992 samples were taken from the upper and middle levels of the intertidal zone in Vargas Lozano, Braithwaite, Blanca SW, Blanca NE, Binners, Grayson, Academia and Norte bays. The 161 species found belong to Porifera, Cnidaria, Platyhelmintha, Nemertina, Sipunculida, Annelida, Mollusca, Anthropoda and Echinodermata. Crustaceans and mollusks were the richest groups in both years, as in other rocky shores. Highest total density was found in Blanca NE bay in both samplings, with 281 orgs./m2 in the first and 172 orgs./m2 in the second. Most frequently found species were Isognomon janus (Mollusca, Pelecypoda), Littorina pullata (Mollusca, Gastropoda), Hipponix panamensis (Mollusca, Gastropoda), Pachygrapsus transversus (Crustacea, Grapsoidea) and Turbo funiculosus (Mollusca, Gastropoda). Because of the complexity of the habitat structure, Vargas Lozano was the bay with the highest specific richness (83 species), greatest diversity (4.7 bits/individual) and lowest dominance (0.065). Most species were classified as accidentals with the Dajoz's frequency classification, while the dominant species were accessories and only I. janus, in the spring 1991, was a constant species. Two kinds of bays were distinguished: those with some dominant species (density) and those in which there was no evident dominance by a particular species. Consequently, the diversity and evenness values were set apart: homogeneous communities (Vargas Lozano and Binners) and heterogeneous communities (Grayson bay and others), characterized by intermediate evenness values. The Jaccard similarity index identified two regions: one formed by bays found mainly in the southwest part of the island (Binners, Vargas Lozano, Braithwaite, Grayson and Blanca SW) and the other found in the northern region that included Blanca NE, Academia and Norte; however, Blanca NE had the most diverse species composition because of its physiographic particularities and because the sediment retained by the filamentous algae on the flat stones allow many species to settle down. Isognomon janus, Mitrella baccata (Mollusca, Gastropoda), P. transversus and Xanthodius cooksoni (Crustacea, Xanthoidea) were the most common species in all bays in both expeditions. The dominance-diversity relationship, the high s

Solid waste characterisation study in the Guadalajara Metropolitan Zone, Mexico.

The key findings of a solid waste characterisation study conducted at the Guadalajara Metropolitan Zone, Mexico, are reported. Objectives of the study were to estimate the daily generation rate of household (HSW) and municipal solid waste (MSW), characterise and compare their composition by type of material, determine the proportion that HSW contributes to MSW, explore changes in MSW composition through time after final disposal, and estimate the types and amount of MSW that are sorted out for recycling at final disposal sites. HSW generated during seven days by a sample of 300 households chosen through a two-stage stratified sampling design was collected, weighed and classified. MSW entering the four local disposal sites was recorded for 12 weeks, and materials' sorting was quantified. MSW samples taken by excavating trenches in two final disposal sites were also characterised. The average per capita daily HSW generation rate was 508 g. HSW mainly consisted of putrescible waste (53%), paper (10%) and plastic (9%). The average daily generation rate of MSW was 3119.2 metric tonnes. HSW represented 55.9% of MSW, and the main difference between HSW and MSW was a lower proportion of organic materials (53% vs. 16.5%, respectively). The major changes in MSW composition through time after final disposal, were the result of the quick decomposition of putrescible materials. Only 2.2% of total MSW generated in Guadalajara (mainly package waste) was sorted for recycling.

Experimental acute intoxication with ripe fruit of Karwinskia humboldtiana (Tullidora) in rat, guinea-pig, hamster and dog.

Previous acute toxicity studies with 'Tullidora' in mice showed mainly hepatic and pulmonary complications. We tested samples in rat, guinea-pig, hamster and dog, searching for the mechanism of death. A single oral preparation of ripe fruit of Karwinskia humboldtiana was given to all animals. Clinical signs and histopathology were reproduced in all species except dogs. We propose a selective toxicity of the toxins of this fruit to the lungs and liver.

Killing of Paracoccidioides brasiliensis conidia by pulmonary macrophages and the effect of cytokines.

The ability of conidia, the infectious form of the dimorphic fungus Paracoccidioides brasiliensis, to be killed in vitro by murine pulmonary macrophages was studied. Mice were immunized by intravenous injection of killed conidia, which resulted in cellular immunity demonstrated by delayed type hypersensitivity in vivo and macrophage migration inhibition factor production in vitro. Resident pulmonary macrophages from non-immune mice were able to significantly kill the conidia (28%). Such macrophages treated with supernatants (cytokines) from antigen-stimulated immune mononuclears had a markedly enhanced ability to kill conidia (73%). These results show that activated pulmonary macrophages are potent killers of conidia of P. brasiliensis and that immune mononuclears play a role in activation of macrophages. Activated macrophages may be important for pulmonary defense against the initial stages of infection with this fungus.

Electron microscopic study of conidia produced by the mycelium of Paracoccidioides brasiliensis.

The ultrastructure of asexual spores (conidia) produced by the mycelial form of Paracoccidioides brasiliensis was studied for the first time with transmission electron microscopy, using thin sections of aldehyde-osmium-fixed and epoxy-resin-embedded samples. The various types of conidia observed in the sections correlated well with previous light-microscopic descriptions. These types were intercalary or apical conidia, depending on their location along the originating hyphae. As in previous studies they were characterized as arthroconidia, aleuriospores and sessile or pedunculate pyriform conidia. The sporogenous cells were clearly distinguished from hyphal cells by the thickness and appearance of their cell walls. Copious fibrillar material (glycocalyx) detected at the cell surface was stained with ruthenium red during the fixation process. Typical subcellular organelles (nucleus, nucleolus, mitochondria, ribosomes, etc) were found in most of the sections. It was concluded that the spores produced by the mycelial phase of P. brasiliensis possess all attributes of viable and physiologically competent eukaryotic cells.

Scanning electron microscopy of the conidia produced by the mycelial form of Paracoccidioides brasiliensis.

The conidia produced by the mycelial form of Paracoccidioides brasiliensis were examined by scanning electron microscopy for the first time. Several different conidial types were characterized. These included intercalary arthroconidia, several types of septate conidia that are formed from other conidia, pedunculate conidia, and terminal hyphal conidia. In addition, the ultrastructure of the supporting pedestal of the pedunculate conidium was found to be separated from the mother conidium by a septum in some instances, and at other times it was not.

Inhibition by estrogens of conidium-to-yeast conversion in the fungus Paracoccidioides brasiliensis.

Conidia produced by Paracoccidioides brasiliensis are inhibited by mammalian estrogens in their in vitro conversion into yeast-form cells. This was demonstrated with four different isolates. In these experiments, conversion was reduced to 10.7 and 34.4% of the control values by 17-beta-estradiol at 10(-6) and 10(-8) M, respectively. At the same concentrations, the synthetic estrogen diethylstilbestrol was slightly less inhibitory. In contrast, other sex hormones and analogs, i.e., testosterone, 17-alpha-estradiol, tamoxifen, and hydroxytamoxifen, had no effect on conidium-to-yeast conversion. Previous studies have shown that estrogens similarly inhibit mycelium-to-yeast-form transition in P. brasiliensis. Conidia, and not mycelial fragments, are believed to be the natural infectious propagules. These findings with conidia support the hypothesis that estrogens, affecting the initial host-parasite interactions by suppressing conversion to the parasitic form of the organism, are, at least in part, responsible for the greater resistance of females to paracoccidioidomycosis.

Morphological study of a variant of Paracoccidioides brasiliensis that exists in the yeast form at room temperature.

Incubation of Paracoccidioides brasiliensis conidia at 20-25 degrees C (RT) results in two types of colonies, mycelial (M) and yeast (YRT). A study of the latter colonies was undertaken. Conidia were plated in complex (BHI) and chemically-defined media (CDCM), with and without fetal calf serum (FCS). Incubation was carried out at 21 degrees C for 4 weeks. The mean number of YRT colonies was approximately 18.5% on BHI agar. Selected YRT colonies were transferred to liquid CDCM, incubated 7 days at 21 degrees C and transferred to solid media; YRT appearance was preserved in 95% of the colonies if media were FCS-supplemented; otherwise, most colonies reverted to the M form. When FCS was replaced by bovine albumin or by alpha-globulin, 63% and 68% respectively of the colonies obtained after plating YRT cells, became mycelial. Comparative morphologic studies of both YRT and yeasts grown at 37 degrees C suggested that there were no major differences between these two types of yeast cells when size and budding were taken into consideration. The results indicate that in this particular variant, dimorphism is not exclusively temperature-dependent.

Nuclear staining of Paracoccidioides brasiliensis conidia.

More than 80% of the conidia produced by two different isolates of Paracoccidioides brasiliensis, were found to be uninucleate; however, when they were incubated at 37 degrees C and began to transform into yeast cells, they became bi- or multi-nucleated, so that when most of the conidia had already transformed into yeast cells (72-96 h), there were at least four or five nuclei per cell in approximately 80% of the conidia examined.

Experimental murine paracoccidiodomycosis induced by the inhalation of conidia.

Adult BALB/c mice of both sexes were infected intranasally with 10(6) viable P. brasiliensis conidia. Animals were sacrificed at intervals up to 6 months and studied by histopathology and organ cultures. At the time of challenge lung sections showed that instilled conidia had reached the alveoli; at 12 h such conidia were transforming into yeast cells, with multiple buds appearing by 18 h. Initially, the cellular infiltrate was composed of polymorphonuclear leukocytes; 6 days later, lymphocytes, plasmocytes and macrophages predominated. Multinucleated giant cells appeared only after 6 weeks. The rate of pulmonary infection as determined by organ culture was high (82 of the 83 mice studied). The experimental infection was progressive as indicated by increasing numbers of viable fungi with time. The results of this study demonstrate that the conidia produced by P. brasiliensis mycelial form are infectious, producing active disease in healthy animals.

Morphological development of the conidia produced by Paracoccidioides brasiliensis mycelial form.

P. brasiliensis conidia were studied for their ability to grow as yeasts or as molds according to temperature. Using a microculture system we found that such conidia shared the ability of the parent mycelium to transform directly into multiple-budding yeast cells at 36 degrees C or to produce germ tubes and branching mycelia if kept at 22 degrees C.

A technique to collect and dislodge conidia produced by Paracoccidioides brasiliensis mycelial form.

Collection and separation of mycelial propagules produced by P. brasiliensis was accomplished by agitation with glass beads, centrifugation and filtration through cotton wool. The mean number of conidia liberated per plate (approximately 1 000 000) and their viability (79%), lead us to think that it is now possible to undertake experimental studies with these propagules.

Morphogenesis of the mycelium-to-yeast transformation in Paracoccidioides brasiliensis.

The sequential changes observed during the mycelium to yeast transformation in Paracoccidioides brasiliensis were studied microscopically. The mycelial elements produced terminal and intercalary swellings which, later on, became chlamydospore-like structures. These increased in size, acquired a double contour and, finally, gave rise to multiple budding cells. Transformation was asynchronous. During the observation period, multiple budding cells and chlamydospores remained attached to the parent mycelium.

Estrogens inhibit mycelium-to-yeast transformation in the fungus Paracoccidioides brasiliensis: implications for resistance of females to paracoccidioidomycosis.

Evidence that disease due to the thermally dimorphic fungus Paracoccidioides brasiliensis occurs post-puberty predominantly in males led us to hypothesize that hormonal factors critically affect its pathogenesis. We show here that estrogens inhibit mycelial- to yeast-form transformation of P. brasiliensis in vitro. Transformation of three isolates was inhibited to 71, 33, and 19% of the control values in the presence of 10(-10), 10(-8), and 10(-6) M 17 beta-estradiol, respectively. The synthetic estrogen diethylstilbestrol was active but less potent than estradiol, whereas testosterone, 17 alpha-estradiol, tamoxifen, and corticosterone were inactive. This function was specifically inhibited, since yeast-to-mycelium transformation, yeast growth, and yeast reproduction by budding were unaffected by 17 beta-estradiol. Of note is the fact that mycelium-to-yeast transformation occurs as the first step in vivo in the establishment of infection. The cytosol of the three isolates studied possesses a steroid-binding protein which has high affinity for 17 beta-estradiol. We believe that this binding protein represents a P. brasiliensis hormone receptor which can also recognize mammalian estrogens. We hypothesize that the ability of estrogen to decrease or delay mycelium-to-yeast transformation at the initial site of infection contributes to or is responsible for the marked resistance of females, and that the binder described is the molecular site of action.

Tratamiento con clindamicina de la malaria por Falciparum resistente. / Treatment with clindamycin of malaria caused by resistant Falciparum

Fueron tratados con clindamicina treinta pacientes con malaria por P. falciparum la mayoria multiquimio-resistentes. En diecinueve, la dosis fue de 20 mg/kg/peso/dia durante siete dias, por via venosa u oral.Seis recibieron la clindamicina a razon de 40 mg/kg/peso/dia venosa durante tres dias y cinco pacientes recibieron 40 mg/kg/peso/dia durante siete dias. La sintomatologia duro, en promedio 2,8 dias.Con el tratamiento la parasitemia ascendio en diecisiete pacientes y la desaparicion de la parasitemia fue, en promedio, de 5.06 dias Todos los pacientes con antecedentes malaricos con infecciones resistentes a la cloroquina y a otras drogas. Los efectos colaterales fueron minimos

[Measurements of the urban low socioeconomic level in families with malnourished infants]. / Mediciones del nivel socioeconómico bajo urbano en familias con lactante desnutrido.

Two measurements of low socioeconomic level (LSL) were compared in a group of families of low socioeconomic strata from the Metropolitan Area of Santiago, Chile. The purpose was to search for an instrument capable of discriminating the more deprived sectors. The sample included 85 families with infant, the experimental group consisted of 42 families with severely malnourished infant, and the control group was formed by 43 families with healthy infant. The modified Graffar Scale and a Specific Index to measure LSL were applied throughout a survey carried out in the mothers. The study also comprised health and sociocultural aspects. Results indicated that the modified Graffar Scale does not discriminate at the level of an apparently homogeneous group. In contrast, the Specific Index does detect significant differences between both groups, as well as correlations between the health and sociocultural variables. The Specific Index is therefore a helpful and easy to use instrument when applied to urban groups of low socioeconomic level.

PIP: 2 measurements of low socioeconomic level (LSL) were compared in a group of families of low socioeconomic strata from the metroplitan area of Santiago, Chile. The purpose was to discover an instrument capable of discriminating the more deprived sectors in the population. The sample included 85 families with infants; the experimental group had 42 families with severely malnourished infants and the control group had 43 families with healthy infants. The modified Graffar Scale and a Specific Index to measure LSL were applied throughout a survey carried out among the mothers. The study also examined health and sociocultural aspects of life among these 2 groups. Results indicated that the modified Graffar Scale does not discriminate at a level of an apparently homogenous group. In contrast, the Specific Index does detect significant differences between the 2 groups, as well as correlations between the health and sociocultural variables. The Specific Index is therefore a helpful and easy instrument to use when applied to LSL urban groups. (author's modified)