A comparative study of cleaning activity of two reef fishes at Fernando de Noronha Archipelago, tropical West Atlantic

Cleaner fishes are usually classified as obligate or facultative cleaners according to their diet and the extent to which their nutritional requirements in the different ontogenetic stages are gained from cleaning. While obligate cleaners clean throughout their lives and ingest mainly food taken from the clients` body surface, facultative cleaners clean only as juveniles and have a broader diet. In addition, some facultative cleaners may experience a relatively higher predation risk, and thus rarely interact with piscivorous fishes. Despite these acknowledged differences, there are very few studies that compare cleaning activity of obligate and facultative cleaners within the same area. Cleaning activity of the obligate cleaner goby Elacatinus cf. randalli and the facultative cleaner wrasse Thalassoma noronhanum were comparatively examined at Fernando de Noronha Archipelago, tropical West Atlantic. The client assemblage attended by the two cleaners differed, as the goby attended a slightly greater diversity of species (22), mostly piscivores and zoobenthivores, and the wrasse attended fewer species (19), mostly planktivores. Chromis multilineata was the most common client species of both cleaners, although body size (which is expected to be positively correlated to clients` ectoparasite load) of C. multilineata individuals attended by the goby was larger than that of the individuals attended by the wrasse. Despite such differences, T. noronhanum showed a surprisingly species-rich client assemblage when compared with other cleaners of the genus Thalassoma. In addition, the frequency and time spent on cleaning interactions, as well as the number of client species attended per 10-min period, was similar for both cleaner species, which indicate that they have important yet complimentary ecological roles in the reef community at Fernando de Noronha Archipelago.

Non-random reef use by fishes at two dominant zones in a tropical, algal-dominated coastal reef

Habitat use and the processes which determine fish distribution were evaluated at the reef flat and reef crest zones of a tropical, algal-dominated reef. Our comparisons indicated significant differences in the majority of the evaluated environmental characteristics between zones. Also, significant differences in the abundances of twelve, from thirteen analyzed species, were observed within and between-sites. According to null models, non-random patterns of species co-occurrences were significant, suggesting that fish guilds in both zones were non-randomly structured. Unexpectedly, structural complexity negatively affected overall species richness, but had a major positive influence on highly site-attached species such as a damselfish. Depth and substrate composition, particularly macroalgae cover, were positive determinants for the fish assemblage structure in the studied reef, prevailing over factors such as structural complexity and live coral cover. Our results are conflicting with other studies carried out in coral-dominated reefs of the Caribbean and Pacific, therefore supporting the idea that the factors which may potentially influence reef fish composition are highly site-dependent and variable.

Genetic variation and population structuring in two brooding coral species (Siderastrea stellata and Siderastrea radians) from Brazil

Siderastrea stellata and S. radians are scleractinian coral species that present a remarkable overlap of diagnostic characteristics and sympatric distribution. Moreover, both are viviparous with similar reproductive strategies and with a gregarious larval behavior. Samples of both species from the Brazilian coast were analyzed using 18 isozymic loci to quantify their genetic variability and populational structure. Results confirmed species identity, high intrapopulational variability and revealed moderate genetic structuring among all samples (S. stellata: F(ST) = 0.070; S. radians: F(ST) = 0.092). Based on genotypic diversity analysis, there was evidence that local recruitment may have a minor role in the populations (mean, G(o) :G(e) = 1.00 +/- 0.0003 SD for S. stellata and 0.99 +/- 0.0023 SD for S. radians). Deviations towards heterozygote deficiencies found in both Siderastrea species could be explained by the Wahlund effect, since there was evidence that populations might be composed of colonies of different ages. In S. radians it is also likely that there is some inbreeding occurring in the studied populations. Despite the brooding pattern and the gregarious larval behavior, our data suggest the occurrence of gene flow along the Brazilian coast. This is the first study on population genetics of Brazilian reef corals.

Vibrios dominate as culturable nitrogen-fixing bacteria of the Brazilian coral Mussismilia hispida

Taxonomic characterization was performed on the putative N-2-fixing microbiota associated with the coral species Mussismilia hispida, and with its sympatric species Palythoa caribaeorum, P. variabilis, and Zoanthus solanderi, off the coast of Sao Sebastiao (Sao Paulo State, Brazil). The 95 isolates belonged to the Gammaproteobacteria according to the 16S rDNA gene sequences. In order to identify the isolates unambiguously, pyrH gene sequencing was carried out. The majority of the isolates (n = 76) fell within the Vibrio core group, with the highest gene sequence similarity being towards Vibrio harveyi and Vibrio alginolyticus. Nineteen representative isolates belonging to V. harveyi (n = 7), V. alginolyticus (n = 8), V. campbellii (n = 3), and V parahaemolyticus (n = 1) were capable of growing six successive times in nitrogen-free medium and some of them showed strong nitrogenase activity by means of the acetylene reduction assay (ARA). It was concluded that nitrogen fixation is a common phenotypic trait among Vibrio species of the core group. The fact that different Vibrio species can fix N, might explain why they are so abundant in the mucus of different coral species. (C) 2008 Published by Elsevier GmbH.

Palythine-threonine, a major novel mycosporine-like amino acid (MAA) isolated from the hermatypic coral Pocillopora capitata

Using a high-resolution reverse-phase liquid chromatography method we found that the tissues of the hermatypic coral Pocillopora capitato (collected in Santiago Bay, Mexico) contain a high diversity of primary and secondary mycosporine-like amino acids (MAAs) typical of some reef-building coral species: mycosporine-glycine, shinorine, porphyra-334, mycosporine-methylamine-serine, mycosporine-methylamine-threonine, palythine-serine, palythine and one additional novel predominant MAA, with an absorbance maximum of 320 nm. Here we document the isolation and characterization of this novel MAA from the coral A capitata. Using low multi-stage mass analyses of deuterated and non deuterated compounds, high-resolution mass analyses (Time of Flight, TOF) and other techniques, this novel compound was characterized as palythine-threonine. Palythine-threonine was also present in high concentrations in the corals Pocillopora eydouxi and Stylophora pistillata indicating a wider distribution of this MAA among reef-building corals. From structural considerations we suggest that palythine-threonine is formed by decarboxylation of porphyra-334 followed by demethylation of mycosporine-methylamine-threonine. (C) 2008 Elsevier B.V. All rights reserved.

Carbapenem stewardship: positive impact on hospital ecology

INTRODUCTION: Excessive group 2 carbapenem use may result in decreased bacterial susceptibility. OBJECTIVE: We evaluated the impact of a carbapenem stewardship program, restricting imipenem and meropenem use. METHODS: Ertapenem was mandated for ESBL-producing Enterobacteriaceae infections in the absence of non-fermenting Gram-negative bacilli (GNB) from April 2006 to March 2008. Group 2 carbapenems were restricted for use against GNB infections susceptible only to carbapenems and suspected GNB infections in unstable patients. Cumulative susceptibility tests were done for nosocomial pathogens before and after restriction using Clinical and Laboratory Standards Institute (CLSI) guide-lines.Vitek System or conventional identification methods were performed and susceptibility testing done by disk diffusion according to CLSI.Antibiotic consumption (t-test) and susceptibilities (McNemar's test) were determined. RESULTS: The defined daily doses (DDD) of group 2 carbapenems declined from 61.1 to 48.7 DDD/1,000 patient-days two years after ertapenem introduction (p = 0.027). Mean ertapenem consumption after restriction was 31.5 DDD/1,000 patient-days. Following ertapenem introduction no significant susceptibility changes were noticed among Gram-positive cocci. The most prevalent GNB were P. aeruginosa, Klebsiella pneumoniae, and Acinetobacter spp. There was no change in P. aeruginosa susceptibility to carbapenems. Significantly improved P. aeruginosa and K. pneumoniae ciprofloxacin susceptibilities were observed, perhaps due to decreased group 2 carbapenem use. K. pneumoniae susceptibility to trimethoprim-sulfamethoxazole improved. CONCLUSION: Preferential use of ertapenem resulted in reduced group 2 carbapenem use, with a positive impact on P. aeruginosa and K. pneumoniae susceptibility.

Ecology and natural history of Akodon lindberghi (Rodentia, Sigmodontinae) in southeastern Brazil

We studied the ecology and natural history of the globally threatened and poorly known Akodon lindberghi Hershkovitz, 1990 in Parque Nacional da Serra da Canastra (PNSC) and Juiz de Fora (JF), southeastern Brazil. From November 1998 to September 2001 a total of 131 individuals were captured in wire-cage live-traps and 52 by pitfalls traps. They were all marked and released at the site. The largest abundances were registered during the dry season, and most of the captures occurred in open habitats. The mean body mass of the two populations was significantly different (18.1 g at PNSC versus 13.1 g at JF; H = 46.2678, g.l.=2, p<0.001). In PNSC, individuals were reproductively active from August to February, and juveniles were present from May to August. The results suggest that the changes in vegetation structure caused by deforestation and intensive agricultural activities could increase the predation rate, affecting the mean body mass of the population.

Transcriptomic basis for an antiserum against Micrurus corallinus (coral snake) venom

Background: Micrurus corallinus (coral snake) is a tropical forest snake belonging to the family Elapidae. Its venom shows a high neurotoxicity associated with pre- and post-synaptic toxins, causing diaphragm paralysis, which may result in death. In spite of a relatively small incidence of accidents, serum therapy is crucial for those bitten. However, the adequate production of antiserum is hampered by the difficulty in obtaining sufficient amounts of venom from a small snake with demanding breeding conditions. In order to elucidate the molecular basis of this venom and to uncover possible immunogens for an antiserum, we generated expressed sequences tags (ESTs) from its venom glands and analyzed the transcriptomic profile. In addition, their immunogenicity was tested using DNA immunization. Results: A total of 1438 ESTs were generated and grouped into 611 clusters. Toxin transcripts represented 46% of the total ESTs. The two main toxin classes consisted of three-finger toxins (3FTx) (24%) and phospholipases A(2) (PLA(2)s) (15%). However, 8 other classes of toxins were present, including C-type lectins, natriuretic peptide precursors and even high-molecular mass components such as metalloproteases and L-amino acid oxidases. Each class included an assortment of isoforms, some showing evidence of alternative splicing and domain deletions. Five antigenic candidates were selected (four 3FTx and one PLA(2)) and used for a preliminary study of DNA immunization. The immunological response showed that the sera from the immunized animals were able to recognize the recombinant antigens. Conclusion: Besides an improvement in our knowledge of the composition of coral snake venoms, which are very poorly known when compared to Old World elapids, the expression profile suggests abundant and diversified components that may be used in future antiserum formulation. As recombinant production of venom antigens frequently fails due to complex disulfide arrangements, DNA immunization may be a viable alternative. In fact, the selected candidates provided an initial evidence of the feasibility of this approach, which is less costly and not dependent on the availability of the venom.

Retention-favorable timing of propagule release in barnacles and periwinkles

Recent studies on the ecology of marine larvae suggest that retention near coastal areas and self-recruitment are probably much more common than previously thought. In light of this, the advective potential of pelagic stages can be partially determined by the timing of propagule release. We sampled the upper-shore levels of a subtropical coastline in southeastern Brazil to examine the temporal patterns of propagule release for the common barnacle Chthamalus bisinuatus and the periwinkle Nodilittorina lineolata. The release timing in both species was very consistent between sites a few kilometers apart. Barnacles released nauplii in a rhythmic pattern, mostly coinciding with neap tides, when the speed of tidal currents was lowest. There was no variation in propagule release in relation to diel or flood-ebb tidal cycles. Periwinkles released propagules in a very irregular pattern, which remarkably matched a time series of wave heights. Egg capsules were released during periods of rough seas, when onshore surface currents were expected to prevail. Eggs were released mostly during ebb tides, and there was no diel variation. Propagule release rhythms are usually viewed as a means to ensure fast offshore advection, thus avoiding presumed hazardous conditions for larvae. However, propagule release strategies in these upper-shore species would more likely contribute to the retention of offspring close to parental stocks.

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 August 2010-30 September 2010

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis x Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

Cellular prion protein modulates defensive attention and innate fear-induced behaviour evoked in transgenic mice submitted to an agonistic encounter with the tropical coral snake Oxyrhopus guibei

The cellular prion protein (PrPC) is a neuronal anchored glycoprotein that has been associated with distinct functions in the CNS, such as cellular adhesion and differentiation, synaptic plasticity and cognition. Here we investigated the putative involvement of the PrPC in the innate fear-induced behavioural reactions in wild-type (WT), PrPC knockout (Prnp(0/0)) and the PrPC overexpressing Tg-20 mice evoked in a prey versus predator paradigm. The behavioural performance of these mouse strains in olfactory discrimination tasks was also investigated. When confronted with coral snakes, mice from both Prnp(0/0) and Tg-20 strains presented a significant decrease in frequency and duration of defensive attention and risk assessment, compared to WT mice. Tg-20 mice presented decreased frequency of escape responses, increased exploratory behaviour, and enhancement of interaction with the snake, suggesting a robust fearlessness caused by PrPC overexpression. Interestingly, there was also a discrete decrease in the attentional defensive response (decreased frequency of defensive alertness) in Prnp(0/0) mice in the presence of coral snakes. Moreover, Tg-20 mice presented an increased exploration of novel environment and odors. The present findings indicate that the PrPC overexpression causes hyperactivity, fearlessness, and increased preference for visual, tactile and olfactory stimuli-associated novelty, and that the PrPC deficiency might lead to attention deficits. These results suggest that PrPC exerts an important role in the modulation of innate fear and novelty-induced exploration. (C) 2008 Published by Elsevier B.V.

Ecology of Rickettsia in South America

Until the year 2000, only three Rickettsia species were known in South America: (i) Rickettsia rickettsii, transmitted by the ticks Amblyomma cajennense, and Amblyomma aureolatum, reported in Colombia, Argentina, and Brazil, where it is the etiological agent of Rocky Mountain spotted fever; (ii) Rickettsia prowazekii, transmitted by body lice and causing epidemic typhus in highland areas, mainly in Peru; (iii) Rickettsia typhi, transmitted by fleas and causing endemic typhus in many countries. During this new century, at least seven other rickettsiae were reported in South America: Rickettsia felis infecting fleas and the tick-associated agents Rickettsia parkeri, Rickettsia massiliae, Candidatus ""Rickettsia amblyommii,"" Rickettsia bellii, Rickettsia rhipicephali, and Candidatus ""Rickettsia andeanae. "" Among these other rickettsiae, only R. felis, R. parkeri and R. massiliae are currently recognized as human pathogens. R. rickettsii is a rare agent in nature, infecting : <= 1% individuals in a few tick populations. Contrastingly, R. parkeri, Candidatus ""R. amblyommii, "" R. rhipicephali, and R. bellii are usually found infecting 10 to 100% individuals in different tick populations. Despite rickettsiae being transmitted transovarially through tick generations, low infection rates for R. rickettsii are possibly related to pathogenic effect of R. rickettsii for ticks, as shown for A. aureolatum under laboratory conditions. This scenario implies that R. rickettsii needs amplifier vertebrate hosts for its perpetuation in nature, in order to create new lines of infected ticks (horizontal transmission). In Brazil, capybaras and opossums are the most probable amplifier hosts for R. rickettsii, among A. cajennense ticks, and small rodents for A. aureolatum.