Tracing the Origin of Dietary Protein in Tropical Dry Forest Birds1

Fundamental to our understanding of the ecology of animal communities in the tropics is knowledge of the effect of seasonal changes in the abundance of food sources in consumer diets. We determined stable‐isotope composition (¹³C/¹²C and ¹⁵N/¹⁴N) in whole blood of 14 resident avian species in a tropical dry forest to quantify the origin of their assimilated protein. We used a probabilistic approach (IsoSource) to estimate the relative contribution of C₃ plants, CAM‐C₄ plants, C₃ insects, and CAM‐C₄ insects during the dry and rainy seasons. IsoSource iteratively creates each possible combination of source contribution and produces a distribution of all feasible combinations that adequately predict the observed isotopic signature of the consumer. Granivore–frugivores and granivore–frugivore–insectivores were modeled as predominantly dependent upon plants whereas insectivorous birds were modeled to derive protein almost exclusively from insects. Between these extremes there were several species using mixed diets such as insectivore–frugivores or insectivore–granivores. In most species, virtually all assimilated food was of C₃ origin with the exception of Ruddy Ground‐Doves (Columbina talpacoti) in which CAM or C₄ plants contributed significantly. Seasonal changes in relative food source contribution were followed in eight species of birds. Of these species, White‐tipped Doves (Leptotila verreauxi), Grayish Saltators (Saltator coerulescens), and Social Flycatchers (Myiozetetes similis) increased their use of insects in the rainy season, in contrast to Great Kiskadees (Pitangus sulphuratus), which decreased their use of insects. Our study suggests that that diverse strategies are used by various avian species to obtain dietary proteins within seasonal habitats.     

A phylogenetic reassessment of Hyalenna Forbes and Dircenna Doubleday, with a revision of Hyalenna (Lepidoptera: Nymphalidae: Ithomiinae)

Abstract.  A morphological study of adults and immature stages and a cladistic analysis were conducted to clarify the relationships amongst members of the sister nymphalid butterfly genera Dircenna Doubleday and Hyalenna Forbes. Two species formerly included in Dircenna , Ithomia paradoxa Staudinger and Dircenna hugia Schaus, clustered with Ithomia perasippa , the type species of Hyalenna . Therefore, the first two species are transferred from Dircenna to Hyalenna ( comb.n .). Hyalenna and Dircenna as now conceived are both monophyletic and well supported by morphological apomorphies and branch support measures. The taxonomy and classification of Hyalenna are reviewed and seven species and twenty-four taxa are recognized, including one new species, Hyalenna buckleyi sp.n. , and eleven new subspecies: Hyalenna paradoxa incachaca ssp.n. , H. perasippa valencia ssp.n. , H. perasippa ortygiosa ssp.n. , H. perasippa solitaria ssp.n. , H. buckleyi pomacocha ssp.n. , H. alidella exsulans ssp.n. , H. alidella cinereola ssp.n. , H. alidella vesca ssp.n. , H. sulmona balsamica ssp.n. , H. sulmona hyalina ssp.n. and H. sulmona tersa ssp.n. A key for the identification of all taxa, and illustrations of male and female genitalia for all species and adult specimens of all taxa (where known), are presented. The natural history of each species is summarized and the immature stages of H. paradoxa and H. sulmona are described for the first time.     

Effects of testosterone on nuclear ribonucleoprotein components of prostate epithelial cells

Summary— The changes of the nuclear components caused by castration and testosterone injection were studied in epithelial cells of the ventral prostate of the rat. Castration drastically diminishes the nuclear and nucleolar volume, as well as the fraction of the nuclear volume occupied by non-nucleolar ribonucleoprotein (RNP) fibrils. However, in castrated animals the frequency of perichromatin granules (PCG) is 79% higher than in controls. Testosterone injection causes a reduction of the number of PCG to 33% of the castrated level in 15 min, and increases the non-nucleolar RNP fibrils. Other parameters such as nuclear and nucleolar volume and the relative volume of the compact chromatin present only small changes in a period of 2 h following the hormone administration. High resolution quantitative autoradiography demonstrates that the transportation of previously synthesized RNA increases steeper than the RNA synthesis. All these effects are similar to those caused by ovariectomy and estradiol injection on the nuclear structures of endometrial epithelial cells. These similarities and other observations suggest that PCGs contain mRNA, of a few genes, stored in the nucleus by a restriction of its transportation to the cytoplasm.     

Symbiosis and insect diversification: an ancient symbiont of sap-feeding insects from the bacterial phylum Bacteroidetes

Several insect groups have obligate, vertically transmitted bacterial symbionts that provision hosts with nutrients that are limiting in the diet. Some of these bacteria have been shown to descend from ancient infections. Here we show that the large group of related insects including cicadas, leafhoppers, treehoppers, spittlebugs, and planthoppers host a distinct clade of bacterial symbionts. This newly described symbiont lineage belongs to the phylum Bacteroidetes. Analyses of 16S rRNA genes indicate that the symbiont phylogeny is completely congruent with the phylogeny of insect hosts as currently known. These results support the ancient acquisition of a symbiont by a shared ancestor of these insects, dating the original infection to at least 260 million years ago. As visualized in a species of spittlebug (Cercopoidea) and in a species of sharpshooter (Cicadellinae), the symbionts have extraordinarily large cells with an elongate shape, often more than 30 mum in length; in situ hybridizations verify that these correspond to the phylum Bacteroidetes. "Candidatus Sulcia muelleri" is proposed as the name of the new symbiont.     

Oligomycin strengthens the effect of cyclosporin A on mitochondrial permeability transition by inducing phosphate uptake

The purpose of this work was to assess the effect of oligomycin on the mitochondrial membrane permeability transition. The antibiotic was found to strengthen cyclosporin A (CSA)-induced protection of non-specific permeability, which is triggered by a matrix Ca2+ load in the absence of ADP. Oligomycin also reinforced the protective effect of CSA on carboxyatractyloside-induced pore opening in the absence of ADP, but failed to do so in mitochondria incubated under anaerobic conditions or after addition of CCCP. Analyzing the efflux of matrix Ca2+, we found that mitochondrial swelling and the collapse of the transmembrane electric gradient coincided with membrane leakage. The effects of the antibiotic were observed in phosphate-containing media but not in the presence of acetate. Furthermore, N-ethylmaleimide hindered the protective effect of oligomycin-CSA. In addition, the matrix phosphate concentration increased concurrently with a diminution in the matrix-free fraction of Ca2+. We concluded that oligomycin increases phosphate uptake by stimulating the phosphate-/OH- exchange reaction.     

Gastroduodenal lesions and Helicobacter pylori infection in dyspeptic patients with and without chronic renal failure

BACKGROUND: Patients with chronic renal failure (CRF) often have dyspeptic symptoms and may develop peptic disease or digestive disorders leading to severe gastrointestinal complications. The primary aim of this study was to evaluate the prevalence of peptic lesions and Helicobacter pylori infection, and the severity of dyspeptic symptoms, in dyspeptic patients with and without CRF. Our secondary aim was to investigate whether uremic status may affect the diagnostic efficiency of the [13]C-urea breath test ([13]C-UBT). PATIENTS AND METHODS: We consecutively enrolled in the study 50 dyspeptic patients with chronic kidney failure (mean age 52 +/- 5 years), of whom 11 were on hemodialysis treatment (HD), and 93 subjects (mean age 54 +/- 7 years) with chronic dyspepsia and normal renal function (NRF). All patients completed an oriented and validated questionnaire scoring the severity of nine dyspeptic symptoms (i.e. epigastric pain, epigastric burning, postprandial fullness, early satiety, bloating, belching, nausea and vomiting) and underwent upper endoscopy with multiple bioptic sampling for rapid urease test and histological examination, [13]C-UBT and HpSA test. RESULTS: The prevalences of peptic lesions and H. pylori infection and mean symptom score were 74%, 52% and 3.5 +/- 3, respectively, in dyspeptic patients with CRF and 18%, 36% and 8 +/- 5, respectively, in dyspeptic patients with NRF. The diagnostic accuracy of [13]C-UBT with respect to histological diagnosis was 94% and 97% for dyspeptic patients with and without renal failure, respectively. CONCLUSIONS: 1, A high frequency of peptic lesions and low symptom scores were observed in uremic patients in spite of H. pylori infection; 2, uremic status did not affect the diagnostic accuracy of [13]C-UBT.     

Comparative culturing of Pleurotus spp. on coffee pulp and wheat straw: biomass production and substrate biodegradation

The results of the cultivation of six strains of Pleurotus (P. djamor (2), P. ostreatus (2) and P. pulmonarius (2)) on coffee pulp and wheat straw are presented. Metabolic activity associated with biomass of each strain was determined, as well as changes in lignin and polysaccharides (cellulose and hemicellulose), phenolic and caffeine contents in substrate samples colonized for a period of up to 36 days. Analysis were made of changes during the mycelium incubation period (16 days) and throughout different stages of fructification. Greater metabolic activity was observed in the wheat straw samples, with a significant increase between 4 and 12 days of incubation. The degradation of polysaccharide compounds was associated with the fruiting stage, while the reduction in phenolic contents was detected in both substrates samples during the first eight days of incubation. A decrease was observed in caffeine content of the coffee pulp samples during fruiting stage, which could mean that some caffeine accumulates in the fruiting bodies.