Phylogeographic evidence for two species of muriqui (genus Brachyteles)

The taxonomy of muriquis, the largest extant primates in the New World, is controversial. While some specialists argue for a monotypic genus (Brachyteles arachnoides), others favor a two‐species classification, splitting northern muriquis (Brachyteles hypoxanthus) from southern muriquis (B. arachnoides). This uncertainty affects how we study the differences between these highly endangered and charismatic primates, as well as the design of more effective conservation programs. To address this issue, between 2003 and 2017 we collected over 230 muriqui fecal samples across the genus’ distribution in the Brazilian Atlantic Forest, extracted DNA from these samples, and sequenced 423 base pairs of the mitochondrial DNA (mtDNA) control region. Phylogenetic and species delimitation analyses of our sequence dataset robustly support two reciprocally monophyletic groups corresponding to northern and southern muriquis separated by an average 12.7% genetic distance. The phylogeographic break between these lineages seems to be associated with the Paraíba do Sul River and coincides with the transition between the north and south Atlantic Forest biogeographic zones. Published divergence estimates from whole mitochondrial genomes and nuclear loci date the split between northern and southern muriquis to the Early Pleistocene (ca. 2.0 mya), and our new mtDNA dataset places the coalescence time for each of these two clades near the last interglacial (ca. 120–80 kya). Our results, together with both phenotypic and ecological differences, support recognizing northern and southern muriquis as sister species that should be managed as distinct evolutionarily significant units. Given that only a few thousand muriquis remain in nature, it is imperative that conservation strategies are tailored to protect both species from extinction.     

Antibiotic resistance in Staphylococci isolated from the vaginas of captive female Leontopithecus (Callitrichidae-Primates)

The purpose of this study was to provide current data on Staphylococcus species from the vaginas of clinically normal captive lion tamarins and to determine the antimicrobial susceptibility of these isolates. Samples were collected from 25 adult lion tamarins, processed to isolate Staphylococcus species, and tested for susceptibility to penicillin G, gentamicin, chloramphenicol, tetracycline, trimethoprim-sulfamethoxazole, streptomycin, ampicillin, and rifampicin. Isolates with the typical characteristics of the genus Staphylococcus were recovered from all 25 samples. Coagulase-negative species were the most common (68% of the isolates), and the most frequently isolated species (10 samples) was S. simulans. Other coagulase-negative species, including S. saprophyticus (n=5), S. epidermidis (n=1), and S. arlettae (n=1), were also recovered. Coagulase-positive Staphylococci were obtained from eight animals (six of from the S. aureus species and two from S. intermedius). Resistance to antibiotics was frequently observed, and 88% of the isolates (23 samples) showed resistance to at least one drug. Resistance to penicillin G was a common finding, and the most active antimicrobial agents were chloramphenicol and gentamicin. Coagulase-positive strains were more frequently resistant to antibiotics (79.7%, average=6.4 drugs) than coagulase-negative strains (38.2%, average=3.0 drugs). The high frequency of resistance observed in those isolates is surprising and very alarming. A detailed history of the use of antimicrobial drugs in these subjects did not reveal any previous exposure to any of the tested antibiotics that could justify the observed resistance rate.     

Alignment-free prediction of mycobacterial DNA promoters based on pseudo-folding lattice network or star-graph topological indices

The importance of the promoter sequences in the function regulation of several important mycobacterial pathogens creates the necessity to design simple and fast theoretical models that can predict them. This work proposes two DNA promoter QSAR models based on pseudo-folding lattice network (LN) and star-graphs (SG) topological indices. In addition, a comparative study with the previous RNA electrostatic parameters of thermodynamically-driven secondary structure folding representations has been carried out. The best model of this work was obtained with only two LN stochastic electrostatic potentials and it is characterized by accuracy, selectivity and specificity of 90.87%, 82.96% and 92.95%, respectively. In addition, we pointed out the SG result dependence on the DNA sequence codification and we proposed a QSAR model based on codons and only three SG spectral moments.     

Structure-activity relationship of wedelolactone analogues: structural requirements for inhibition of Na+, K+ -ATPase and binding to the central benzodiazepine receptor

Coumestans 2a-i, bearing different patterns of substitution in A- and D-rings, were synthesized and evaluated as inhibitors of kidney Na+, K+ -ATPase and ligands for the central benzodiazepine (BZP) receptor. The presence of a hydroxyl group in position 2 favours the effect on Na+, K+ -ATPase but decreases the affinity for the BZP receptor, allowing the design of more selective molecules than the natural wedelolactone. On the other hand, the presence of a catechol in ring D is important for the effect on both molecular targets.     

Pathogenicity of hyphomycet fungi to aphids Aphis gossypii Glover and Myzus persicae (Sulzer) (Hemiptera: Aphididae)

The aphids Aphis gossypii and Myzus persicae are cosmopolitan, poliphagous and damage cultivated plants. The effects of the entomopathogenic fungi Beauveria bassiana (isolate IBCB 66), Metarhizium anisopliae (isolate IBCB 121), Paecilomyces fumosoroseus (isolate IBCB 141) and Lecanicillium (= Verticillium) lecanii (isolate JAB 02) on third instar nymphs of A. gossypii and M. persicae were evaluated in the laboratory at 25 degrees C, 70 +/- 10% RH and 12h photophase. The aphids were transferred to petri dishes with a foliar disk (cotton or pepper) with a layer of 1 cm tick of agar-water. The fungi were applied in a suspension containing 1.0 x 106 to 1.0 x 108 conidia/ml. In the control treatment 1 ml of sterilized water was added to the foliar disks. The mortality of aphids was evaluated daily. B. bassiana and M. anisopliae caused 100% mortality at the seventh day after inoculation, for both species. L. lecanii was the fungus that provided mortality later in the aphids and M. persicae was more susceptible to both fungi than A. gossypii.     

A new karyotype of an endangered primate species (Callicebus personatus) from the Brazilian Atlantic forests

The genus Callicebus has 28 species arranged in five groups: donacophilus, torquatus, moloch, cupreus and personatus. The personatus group occurs in the Brazilian Atlantic forests where it is isolated from the other Callicebus groups. The present paper is the first report on the karyotype of Callicebuspersonatus. We compared the karyotypes of C. personatus and C. nigrifrons utilizing the following classic banding techniques: G-, C-, NOR banding, G/C- and G/NOR sequential banding. The karyotype of C. personatus has 2n=44, while C. nigrifrons presented 2n=42. Both the species diverge in the diploid number in consequence of a rearrangement type centric fusion/fission. Our results support personatus as a valid group and the specific status for C. personatus and C. nigrifrons.     

On the mechanism of activation of the plasma membrane Ca2+-ATPase by ATP and acidic phospholipids

The activation of purified and phospholipid-depleted plasma membrane Ca2+-ATPase by phospholipids and ATP was studied. Enzyme activity increased with [ATP] along biphasic curves representing the sum of two Michaelis-Menten equations. Acidic phospholipids (phosphatidylinositol (PI) and phosphatidylserine (PS)) increased Vmax without affecting apparent affinities of the ATP sites. In the presence of 20 microm ATP, phosphorylation of the enzyme preincubated with Ca2+ (CaE1) was very fast (kapp congruent with 400 s-1). vo of phosphorylation of CaE1 increased with [ATP] along a Michaelis-Menten curve (Km of 15 microm) and was phospholipid-independent. Without Ca2+ preincubation (E1 + E2), vo of phosphorylation was also phospholipid-independent, but was slower and increased with [ATP] along biphasic curves. The high affinity component reflected rapid phosphorylation of CaE1, the low affinity component the E2 --> E1 shift, which accelerated to a rate higher than that of the ATPase activity when ATP was bound to the regulatory site. Dephosphorylation of EP did not occur without ATP. Dephosphorylation increased along a biphasic curve with increasing [ATP], showing that ATP accelerated dephosphorylation independently of phospholipid. PI, but not phosphatidylethanolamine (PE), accelerated dephosphorylation even in the absence of ATP. kapp for dephosphorylation was 57 s-1 at 0 microM ATP; that rate was further increased by ATP. Steady-state [EP] x kapp for dephosphorylation varied with [ATP], and matched the Ca2+-ATPase activity measured under the same conditions. Apparently, the catalytic cycle is rate-limited by dephosphorylation. Acidic phospholipids stimulate Ca2+-ATPase activity by accelerating dephosphorylation, while ATP accelerates both dephosphorylation and the conformational change from E2 to E1, further stimulating the ATPase activity.     

First characterization of Candida albicans by random amplified polymorphic DNA method in Nicaragua and comparison of the diagnosis methods for vaginal candidiasis in Nicaraguan women

A total of 106 women with vaginitis in Nicaragua were studied. The positive rate for the identification of Candida species was 41% (44 positive cultures out of 106 women with vaginitis). The sensitivity of microscopic examination of wet mount with the potassium hydroxide (KOH) was 61% and 70% with Gram's stain when using the culture of vaginal fluid as gold standard for diagnosis of candidiasis. Among the 44 positives cultures, isolated species of yeast from vaginal swabs were C. albicans (59%), C. tropicalis (23%), C. glabrata (14%) and C. krusei (4%). This study reports the first characterization of 26 C. albicans stocks from Nicaragua by the random amplified polymorphic DNA method. The genetic analysis in this small C. albicans population showed the existence of linkage disequilibrium, which is consistent with the hypothesis that C. albicans undergoes a clonal propagation.