An Intriguing Shift Occurs in the Novel Protein Phosphatase 1 Binding Partner,TCTEX1D4: Evidence of Positive Selection in a Pika Model

T-complex testis expressed protein 1 domain containing 4 (TCTEX1D4) contains the canonical phosphoprotein phosphatase 1 (PPP1) binding motif, composed by the amino acid sequence RVSF. We identified and validated the binding of TCTEX1D4 to PPP1 and demonstrated that indeed this protein is a novel PPP1 interacting protein. Analyses of twenty-one mammalian species available in public databases and seven Lagomorpha sequences obtained in this work showed that the PPP1 binding motif ₉₀RVSF₉₃ is present in all of them and is flanked by a palindromic sequence, PLGS, except in three species of pikas (Ochotona princeps, O. dauurica and O. pusilla). Furthermore, for the Ochotona species an extra glycosylation site, motif ₉₆NLS₉₈, and the loss of the palindromic sequence were observed. Comparison with other lagomorphs suggests that this event happened before the Ochotona radiation. The d_N/d_S for the sequence region comprising the PPP1 binding motif and the flanking palindrome highly supports the hypothesis that for Ochotona species this region has been evolving under positive selection. In addition, mutational screening shows that the ability of pikas TCTEX1D4 to bind to PPP1 is maintained, although the PPP1 binding motif is disrupted, and the N- and C-terminal surrounding residues are also abrogated. These observations suggest pika as an ideal model to study novel PPP1 complexes regulatory mechanisms.     

Microbial Community Diversity in the Gut of the South American Termite Cornitermes cumulans (Isoptera: Termitidae)

Termites inhabit tropical and subtropical areas where they contribute to structure and composition of soils by efficiently degrading biomass with aid of resident gut microbiota. In this study, culture-independent molecular analysis was performed based on bacterial and archaeal 16S rRNA clone libraries to describe the gut microbial communities within Cornitermes cumulans, a South American litter-feeding termite. Our data reveal extensive bacterial diversity, mainly composed of organisms from the phyla Spirochaetes, Bacteroidetes, Firmicutes, Actinobacteria, and Fibrobacteres. In contrast, a low diversity of archaeal 16S rRNA sequences was found, comprising mainly members of the Crenarchaeota phylum. The diversity of archaeal methanogens was further analyzed by sequencing clones from a library for the mcrA gene, which encodes the enzyme methyl coenzyme reductase, responsible for catalyzing the last step in methane production, methane being an important greenhouse gas. The mcrA sequences were diverse and divided phylogenetically into three clades related to uncultured environmental archaea and methanogens found in different termite species. C. cumulans is a litter-feeding, mound-building termite considered a keystone species in natural ecosystems and also a pest in agriculture. Here, we describe the archaeal and bacterial communities within this termite, revealing for the first time its intriguing microbiota.     

Cytogenetic characterization of the ant Trachymyrmex fuscus Emery, 1934 (Formicidae: Myrmicinae: Attini) with the description of a chromosomal polymorphism

The genus Trachymyrmex is a key group in the tribe Attini because of its close phylogenetic relationship to leaf-cutter ants, Acromyrmex and Atta. Cytogenetic data are only available for five taxa of Trachymyrmex, with chromosome numbers of 2n = 12, 18, 20 and 22, and morphology with predominantly metacentric chromosomes. The aim of the present study was to characterize the karyotype of the ant Trachymyrmex fuscus Emery, 1934, by means of the number and morphology of its chromosomes, heterochromatin pattern, CMA₃ and DAPI fluorochromes in the population of two nests collected at Paraopeba, state of Minas Gerais, Brazil. Nineteen females presented 2n = 18 chromosomes (16m + 2sm) and a single male presented n = 9 (8m + 1sm). A size chromosomal polymorphism involving the short arm of the submetacentric pair was confirmed by statistical analysis, with three character conditions: heterozygous SB (with a difference in size between the short arms), standard SS (smaller short arms) and homozygote BB (bigger short arms). In the first nest, both SB and SS workers were observed. The other nest contained heterozygous (SB), homozygous (BB), and a male carrying the B chromosome (larger size). The presence of heterochromatin on all centromeric and pericentromeric chromosomes of T. fuscus suggests that the size difference observed in the submetacentric pair in the SB and BB workers is not related to the heterochromatin but to a duplication of euchromatic regions through intra- or inter- chromosomal rearrangements. The fluorochrome CMA₃ matched the C-banding markings, indicating that the heterochromatin is rich in GC base pairs. As far as we know, this is the first chromosomal polymorphism reported in the tribe Attini.     

Serological Survey of Paracoccidioidomycosis in Cats

The objective of the present study was to evaluate infection of cats by Paracoccidioides brasiliensis. Serum samples of 136 cats from rural (n = 86) and urban areas (n = 50) were analyzed by indirect ELISA and immunodiffusion test using P. brasiliensis gp43 and exoantigen as antigens, respectively, and an overall reactivity of 31.6 % was observed by ELISA although no reactivity was detected by immunodiffusion. The positivity observed in animals living in rural areas (48.8 %) with free access to soil was significantly higher (P < 0.0001) than among urban animals (2 %) with limited access to soil, although no significant difference was observed in relation to age or sex. The high rates of positivity observed in cats from rural areas suggest that not diagnosed cases of this mycosis may be occurring in cats living in endemic areas for human paracoccidioidomycosis. This is the first report showing serological evidence of P. brasiliensis infection in cats.     

Feline Nasal Granuloma Due to Cryptoccocus gattii Type VGII

The aims of this study are to make a more precise identification of the etiologic agent of a nasal granuloma in a cat, to verify the susceptibility to the antifungal drugs: ketoconazole, itraconazole, fluconazole, posaconazole, voriconazole, amphotericin B and the proper treatment. Part of the granuloma’s fragment was removed, added to a saline solution and sent to the Laboratory of Mycology. The solution was then seeded in Sabouraud dextrose agar, and the yeast was primarily identified by the traditional methods. The confirmation of the specie Cryptococcus gattii and its molecular type were performed using the PCR–RFLP molecular techniques. The antifungal susceptibility was verified by using the E-test method, and the cat was treated with itraconazole associated with 5-flucytosine. The isolated strain was identified as C. gattii type VGII and was susceptible to all antifungal drugs tested. The treatment with itraconazole associated with 5-flucytosine led to the cure of granulomatous lesions in the feline after 6 months. The characterization and molecular investigation of this microorganism are relevant because they could help us better understand the epidemiology of the infection and to guide us to treat properly the disease.     

Floral polymorphism in Chamaecrista flexuosa (Fabaceae-Caesalpinioideae): a possible case of atypical enantiostyly?

Background and Aims

Reciprocal herkogamy, including enantiostyly and heterostyly, involves reciprocity in the relative positions of the sexual elements within the flower. Such systems result in morphologically and, since pollen is deposited on and captured from different parts of the pollinator, functionally distinct floral forms. Deviations from the basic pattern may modify the functionality of these mechanisms. For heterostylous species, such deviations are generally related to environmental disturbances, pollination services and/or reduced numbers of one floral morph. Deviations for enantiostylous species have not yet been reported. This study aims to investigate enantiostyly in Chamaecrista flexuosa, in particular the presence of deviations from the standard form, in an area of coastal vegetation in north-east Brazil.

Methods

Observations and investigations of floral biology, the reproductive system, pollinator behaviour, floral morphology and morphometry were performed.

Key Results

In C. flexuosa flowers, anthers of different size but similar function are grouped. The flowers were self-compatible and set fruits after every treatment, except in the spontaneous self-pollination experiment, thereby indicating their dependence on pollen vectors. The flowers were pollinated by bees, especially Xylocopa cearensis and X. grisencens. Pollen is deposited and captured from the ventral portion of the pollinator''s body. Variations in the spatial arrangement of floral elements allowed for the identification of floral morphs based on both morphological and functional criteria. Using morphological criteria, morphologically right (MR) and morphologically left (ML) floral morphs were identified. Three floral morphs were identified using functional criteria: functionally right (FR), functionally central (FC) and functionally left (FL). Combinations of morphologically and functionally defined morphs did not occur in equal proportions. There was a reduced frequency of the MR–FR combination.

Conclusions

The results indicate the occurrence of an atypical enantiostyly in C. flexuosa. This seems to improve reproductive success by increasing the efficiency of pollen deposition and capture.     

Influence of Gasoline Inhalation on the Enantioselective Pharmacokinetics of Fluoxetine in Rats

Fluoxetine is used clinically as a racemic mixture of (+)‐(S) and (–)‐(R) enantiomers for the treatment of depression. CYP2D6 catalyzes the metabolism of both fluoxetine enantiomers. We aimed to evaluate whether exposure to gasoline results in CYP2D inhibition. Male Wistar rats exposed to filtered air (n = 36; control group) or to 600 ppm of gasoline (n = 36) in a nose‐only inhalation exposure chamber for 6 weeks (6 h/day, 5 days/week) received a single oral 10‐mg/kg dose of racemic fluoxetine. Fluoxetine enantiomers in plasma samples were analyzed by a validated analytical method using LC‐MS/MS. The separation of fluoxetine enantiomers was performed in a Chirobiotic V column using as the mobile phase a mixture of ethanol:ammonium acetate 15 mM. Higher plasma concentrations of the (+)‐(S)‐fluoxetine enantiomer were found in the control group (enantiomeric ratio AUC_{(+)‐(S)/(–)‐(R)} = 1.68). In animals exposed to gasoline, we observed an increase in AUC_0‐∞ for both enantiomers, with a sharper increase seen for the (–)‐(R)‐fluoxetine enantiomer (enantiomeric ratio AUC_{(+)‐(S)/(–)‐(R)} = 1.07), resulting in a loss of enantioselectivity. Exposure to gasoline was found to result in the loss of enantioselectivity of fluoxetine, with the predominant reduction occurring in the clearance of the (–)‐(R)‐fluoxetine enantiomer (55% vs. 30%). Chirality 25:206–210, 2013. © 2013 Wiley Periodicals, Inc.     

Vacuolaria tropicalis,a new species of Chloromonad from Southern Brazil

Vacuolaria tropicalis sp. nov. is here described as a new species of Chloromonadophyceae, observed in material collected during the summer of 1968–1969 from an artificial pool behind the greenhouses in the São Paulo Botanical Garden in the city of São Paulo. It is distinguished from the three previously described species of the genus chiefly by cell shape and by colour and localisation of the chromatophores.