Systematic revision of the genus Petromica Topsent (Demospongiae: Halichondrida), with a new species from the southwestern Atlantic

The status, scope and classification of the sublithistid demosponge genus Petromica Topsent are revised through morphological analysis of museum specimens of all seven species (including proposed synonyms and varieties), two of which were collected and observed in situ along the Brazilian coast (P. ciocalyptoides (Van Soest & Zea) and P. citrina sp. n.). The synonymy of Petromica and Monanthus Kirkpatrick with priority to the former is justified due to the consistent presence of monocrepid rhizoclone desmas and oxeas in an halichondroid arrangement, and to the lack of co-variance in other morphological characters among the species studied (presence and shape of papillae, surface texture, ectosomal skeleton and desma shape). The proposed synonymy of P. grimaldii Topsent and P. massalis Dendy is refuted due to differences in habit and spicule shape between the two species. Three forms described as varieties of Monanthus plumosus Kirkpatrick are raised to species level: P. plumosa (Kirkpatrick), P. tubulata (Kirkpatrick) and P. digitata (Burton). Phylogenetic analysis indicates that two possibly monophyletic clades may be recognized within Petromica, although with low bootstrap support (35–59%): (P. ciocalyptoides, P. citrina) and (P. grimaldii, P. massalis) (P. plumosa) (P. tubulata) (P. digitata). The classification of Petromica within the Halichondriidae (order Halichondrida) is supported by the confused reticulation of long oxeote spicules with ascending spicule tracts, present in all species of the genus.     

Multilocus phylogeographical analysis of Trypanosoma (Megatrypanum) genotypes from sympatric cattle and water buffalo populations supports evolutionary host constraint and close phylogenetic relationships with genotypes found in other ruminants

Species of the subgenus Trypanosoma (Megatrypanum) have been reported in cattle and other domestic and wild ruminants worldwide. A previous study in Brazil found at least four genotypes infecting cattle (Bos taurus), but only one in water buffalo (Bubalus bubalis). However, the small number of isolates examined from buffalo, all inhabiting nearby areas, has precluded evaluation of their diversity, host associations and geographical structure. To address these questions, we evaluated the genetic diversity and phylogeographical patterns of 25 isolates from water buffalo and 28 from cattle from four separate locations in Brazil and Venezuela. Multigene phylogenetic analyses of ssrRNA, internal transcribed spacer of rDNA (ITSrDNA), 5SrRNA, glycosomal glyceraldehyde 3-phosphate dehydrogenase (gGAPDH), mitochondrial cytochrome b (Cyt b), spliced leader (SL) and cathepsin L-like (CATL) sequences positioned all isolates from sympatric and allopatric buffalo populations into the highly homogeneous genotype TthIA, while the cattle isolates were assigned to three different genotypes, all distinct from TthIA. Polymorphisms in all of these sequences separated the trypanosomes infecting water buffalo, cattle, sheep, antelope and deer, and suggested that they correspond to separate species. Congruent phylogenies inferred with all genes indicated a predominant clonal structure of the genotypes. The multilocus analysis revealed one monophyletic assemblage formed exclusively by trypanosomes of ruminants, which corresponds to the subgenus T. (Megatrypanum). The high degree of host specificity, evidenced by genotypes exclusive to each ruminant species and lack of genotype shared by different host species, suggested that the evolutionary history of trypanosomes of this subgenus was strongly constrained by their ruminant hosts. However, incongruence between ruminant and trypanosome phylogenies did not support host-parasite co-evolution, indicating that host switches have occurred across ruminants followed by divergences, giving rise to new trypanosome genotypes adapted exclusively to one host species.     

Cysteine proteases of Trypanosoma (Megatrypanum) theileri: Cathepsin L-like gene sequences as targets for phylogenetic analysis,genotyping diagnosis

Although Trypanosoma theileri and allied trypanosomes are the most widespread trypanosomes in bovids little is known about proteolytic enzymes in these species. We have characterized genes encoding for cathepsin L-like (CATL) cysteine proteases from isolates of cattle, water buffalo and deer that largely diverged from homologues of other trypanosome species. Analysis of 78 CATL catalytic domain sequences from 22 T. theileri trypanosomes disclosed 6 genotypes tightly clustered together into the T. theileri clade. The CATL genes in these trypanosomes are organized in tandem arrays of ～ 1.7 kb located in 2 chromosomal bands of 600–720 kb. A diagnostic PCR assay targeting CATL sequences detected T. theileri of all genotypes from cattle, buffaloes and cervids and also from tabanid vectors. Expression of T. theileri cysteine proteases was demonstrated by proteolytic activity in gelatin gels and hydrolysis of Z-Phe-Arg-AMC substrate. Results from this work agree with previous data using ribosomal and spliced leader genes demonstrating that CATL gene sequences are useful for diagnosis, population genotyping and evolutionary studies of T. theileri trypanosomes.     

Phospholipid Containing Choline Histochemistry of Mouse Uterine Epithelia during Preimplantation Stage

The physiological role of high lipid content in endometrial cells during pregnancy has not been well established. In the present work we used histochemical techniques to analyze the total lipids and phospholipid containing choline (PCC) in the mouse uterine glandular and luminal epithelia during preimplantation stage. Sudan black histochemistry showed the highest intensity during the second day of pregnancy in both the basal and apical portions of luminal epithelium. Peaks of PCC staining were seen both in the luminal and glandular epithelia at the second and fifth days of pregnancy. Changes in localization and in the amount of lipid in the uterine epithelia suggest high mobility and metabolic rates of this substance, which maybe related to morphological and/or functional changes occurring at the same time in the pregnant uterus. The increase and depletion timing of PCC content in the uterine epithelia during preimplantation stage, when uterine prostaglandin is also oscillating, suggest a possible involvement of PCC in prostaglandin biosynthesis. Therefore, the fate of lipid droplets found in the uterine epithelia may be related to critical changes of the pregnant endometrium, rather than the nourishment of developing embryos alone.