Parasitism Behavior of Tetrastichus howardi (Hymenoptera: Eulophidae) on Larvae and Pupae of Sugarcane Borers

Journal of Insect Behavior - Control of the sugarcane borers, Diatraea saccharalis and Diatraea impersonatella (= D. flavipennella) (Lepidoptera: Crambidae), in Brazil, is based on mass release of...     

The Role of Historical Barriers in the Diversification Processes in Open Vegetation Formations during the Miocene/Pliocene Using an Ancient Rodent Lineage as a Model

The Neotropics harbors a high diversity of species and several hypotheses have been proposed to account for this pattern. However, while species of forested domains are frequently studied, less is known of species from open vegetation formations occupying, altogether, a larger area than the Amazon Forest. Here we evaluate the role of historical barriers and the riverine hypothesis in the speciation patterns of small mammals by analyzing an ancient rodent lineage (Thrichomys, Hystricomorpha). Phylogenetic and biogeographic analyses were carried out with mitochondrial and nuclear DNA markers to analyze the evolutionary relationships between Thrichomys lineages occurring in dry domains along both banks of the Rio São Francisco. This river is one of the longest of South America whose course and water flow have been modified by inland tectonic activities and climate changes. Molecular data showed a higher number of lineages than previously described. The T. inermis species complex with 2n = 26, FN = 48 was observed in both banks of the river showing a paraphyletic arrangement, suggesting that river crossing had occurred, from east to west. A similar pattern was also observed for the T. apereoides complex. Thrichomys speciation occurred in Late Miocene when the river followed a different course. The current geographic distribution of Thrichomys species and their phylogenetic relationships suggested the existence of frequent past connections between both banks in the middle section of the Rio São Francisco. The extensive palaeodune region found in this area has been identified as a centre of endemism of several vertebrate species and is likely to be a center of Thrichomys diversification.     

The interplay between increased tooth crown‐height and chewing efficiency,and implications for Cervidae evolution

Mammals of numerous lineages have evolved high‐crowned (hypsodont) teeth particularly during the last 20 million years. This major phenotypic change is one of the most widely studied evolutionary phenomena in a broad range of disciplines, though the mechanisms underlying its transformation remain unresolved. Here, we present the first Finite Element Analysis (FEA) to investigate the alternative hypothesis that there is a biomechanical link between increased hypsodonty and a more effective mastication in deer. Our FE experiments compared patterns of stress and strain within and between different fossil and living species under different loading conditions, and found that more hypsodont teeth are suited for restricting stresses to those areas where chewing loading occurs. This mechanical improvement is consequence of specific and pronounced variations in tooth geometry and morphology of the occlusal surface that are strongly related to crown growth in the vertical plane. We demonstrate that hypsodonty enables selenodont‐teeth to adopt a mechanically improved design that increases the pressure whilst shearing foods. As ruminants are physiologically limited by both the quantity of food consumed and the time spent in the mastication and digestion, hypsodonty is highly advantageous when feeding on mechanically resistant, tough and fibrous foods. Consequently, it allows grass‐eaters to spend less time chewing, thereby increasing the volume of food ingested and/or providing more time for digestion. This study provides a promising line of evidences in support of biomechanical effectiveness, in addition to or instead of increased wear resistance, as a factor in explaining the evolutionary origins of the hypsodont phenotype.     

Antinoceptive and Anti-inflammatory Activities of the Ethanolic Extract,Fractions and Flavones Isolated from Mimosa tenuiflora (Willd.) Poir (Leguminosae)

The bark of Mimosa tenuiflora (Willd.) Poiret (Leguminosae family), popularly known as “jurema preta” in Brazil, is used by the population of Contendas of Sincorá (Bahia State, Brazil) for the treatment of coughs and wound healing. Thus, the aim of this study was to evaluate the antinociceptive and anti-inflammatory activities of the bark ethanol extract (EEMT) and solvent soluble fractions (hexane—H, DCM—D, EtOAc—E and BuOH—B) of the extract in vivo. Additionally, we synthesized 5,7-dihidroxy-4’-methoxyflavanone (isosakuranetin) and isolated the compound sakuranetin, and both compounds were also tested. The anti-inflammatory and antinociceptive assays performed were: writhing test; nociception induced by intraplantar formalin injection; leukocyte recruitment to the peritoneal cavity; evaluation of vascular permeability (Evans blue test); and evaluation of mechanical hypernociception (von Frey test). Production of TNF-α, IL-10, myeloperoxidase and the expression of ICAM-1 were also evaluated. Statistical analysis was performed by one-way ANOVA followed by the Bonferroni post-test (n = 8), with P < 0.05. The EEMT showed antinociceptive activities in writhing test (100–200 mg/kg), in the second phase of the formalin test (50–200 mg/kg), and in mechanical hypernociception (100 mg/kg). EEMT showed an anti-inflammatory effect by reducing neutrophil migration to the peritoneal cavity and in the plantar tissue detected by the reduction of myeloperoxidase activity (100 mg/kg), reduction of IL-10 levels and expression of ICAM-1 in the peritoneal exudate and the mesentery (100 mg/kg), respectively. The four soluble EEMT fractions showed good results in tests for antinociceptive (H, D, E, B) and anti-inflammation (H, D, E). Only sakuranetin showed reduction of the writhing and neutrophil migration (200 mg/kg). Thus, the EEMT and soluble fractions of M. tenuiflora bark demonstrated great antinociceptive and anti-inflammatory activities, as also sakuranetin. More studies should be conducted to elucidate the mechanism of action of this compound. To the best of our knowledge, this is the first report on the antinociceptive activity of the M. tenuiflora fractions and the bioactive isolated compound sakuranetin in vivo.     

Facilitated invasion of an overseas invader: human mediated settlement and expansion of the giant African snail, <Emphasis Type="Italic">Lissachatina fulica</Emphasis>, in Cuba

The giant African snail, Lissachatina fulica, is considered one of the most invasive species worldwide, acting as a crop pest and diseases vector. It was first detected in Cuba in 2014 and is dispersing throughout Havana. We mapped 34 sites in the vicinity of Havana to assess its spread and analysed ecological (forestation and humidity) and anthropogenic (pollution and religious sites) factors in relation to the presence/absence of the snails using multivariate correspondence analysis. There were 14 sites at which the snail was present and where religious rituals of the Yoruba creed, an African rooted religion, were observed. No other variables showed significant relationships. This indicates that the rituals may be a major factor in the dispersal of the snail in Havana and more widely in Cuba. In light of this an outreach program with key Yoruba leaders may help in slowing the dispersal of the snail within Cuba, once the threats posed by this species are known.     

Chk2 is a tumor suppressor that regulates apoptosis in both an ataxia telangiectasia mutated (ATM)-dependent and an ATM-independent manner

In response to ionizing radiation (IR), the tumor suppressor p53 is stabilized and promotes either cell cycle arrest or apoptosis. Chk2 activated by IR contributes to this stabilization, possibly by direct phosphorylation. Like p53, Chk2 is mutated in patients with Li-Fraumeni syndrome. Since the ataxia telangiectasia mutated (ATM) gene is required for IR-induced activation of Chk2, it has been assumed that ATM and Chk2 act in a linear pathway leading to p53 activation. To clarify the role of Chk2 in tumorigenesis, we generated gene-targeted Chk2-deficient mice. Unlike ATM(-/-) and p53(-/-) mice, Chk2(-/-) mice do not spontaneously develop tumors, although Chk2 does suppress 7,12-dimethylbenzanthracene-induced skin tumors. Tissues from Chk2(-/-) mice, including those from the thymus, central nervous system, fibroblasts, epidermis, and hair follicles, show significant defects in IR-induced apoptosis or impaired G(1)/S arrest. Quantitative comparison of the G(1)/S checkpoint, apoptosis, and expression of p53 proteins in Chk2(-/-) versus ATM(-/-) thymocytes suggested that Chk2 can regulate p53-dependent apoptosis in an ATM-independent manner. IR-induced apoptosis was restored in Chk2(-/-) thymocytes by reintroduction of the wild-type Chk2 gene but not by a Chk2 gene in which the sites phosphorylated by ATM and ataxia telangiectasia and rad3(+) related (ATR) were mutated to alanine. ATR may thus selectively contribute to p53-mediated apoptosis. These data indicate that distinct pathways regulate the activation of p53 leading to cell cycle arrest or apoptosis.     

A new species of Heteromyoxyuris (Nematoda: Oxyuridae), parasite of Perognathus flavus (Rodentia: Heteromyidae) from Mexico

Heteromyoxyuris otomii n. sp., which inhabits the intestinal caecum of Perognathus flavus (Heteromyidae), in Zaragoza, Hidalgo, Mexico, is described. This new species differs from the 2 other congeneric species in the morphology and length of lateral alae in males. Heteromyoxyuris deserti has simple lateral alae located at both sides of the body, whereas in the new species, these structures are double at both sides; in contrast, lateral alae of Heteromyoxyuris longejector begin at the posterior half of the body, whereas they arise in the first third in the new species. Heteromyoxyuris longejector was found in 2 new host species, i.e., Perognathus amplus and Chaetodipus hispidus. This record represents the first record for the species in Mexico, increasing its geographic distribution.     

Subcellular localisation of VEGF in different pituitary cells. Changes of its expression in oestrogen induced prolactinomas

Summary Vascular endothelial growth factor (VEGF) is an important angiogenic factor in the pituitary gland. The objective of this study was to unveil the VEGF subcellular localisation in different pituitary cell types and to evaluate changes in its expression at different time intervals after oestrogen stimulation. A relevant feature demonstrated was the identification of this cytokine in the nucleus and cytoplasm of lactotrophs, somatotrophs and gonadotrophs, as well as in follicle-stellate cells of male rats. Oestrogen treatment increased the number of VEGF immunopositive cells and its expression detected differentially by western blot in both nucleus and cytoplasm of pituitary cells when compared to the control. At ultrastructural level VEGF appeared associated with nucleolus and euchromatin involving a possible internal autocrine loop. In lactotrophs, the predominant cell of the tumour, VEGF was immunodetected in RER, Golgi complex, and vesicular organelles, supporting further the association with an auto-paracrine effect exerted by VEGF. The nucleus/cytoplasm ratio of VEGF revealed a prevalent accumulation of VEGF in the cytoplasm. The presence of VEGF in the nucleus may probably be associated with a translocation to this cell compartment. This study demonstrated a cytoplasmic and nuclear immunolocalisation of VEGF in normal and tumoural adenohypophyseal cells. In the course of prolactinoma development, the oestrogen stimulated VEGF expression in tumoural cells, promoting a vascular adaptation which contributes to growth and progression of the tumour.     

Ultrastructure and Immunofluorescence of the midgut of Bombus morio (Hymenoptera: Apidae: Bombini)

Bumblebees are widely distributed across the world and have great economic and ecological importance as pollinators in the forest as well as in agriculture. The insect midgut consists of three cell types, which play various important roles in digestion, absorption, and hormone production. The present study characterized the anterior and posterior midgut regions of the bumblebee, Bombus morio. The digestive, regenerative and endocrine cells in the midgut showed regional differences in their number, nuclear size, as well as the size of the striated border. Ultrastructurally, the digestive cells contained many mitochondria and long microvilli; however, in the anterior midgut region, these cells showed dilated basal labyrinths with a few openings for the hemocoel, whereas the labyrinths of the basal posterior region remained inverse characteristics. Thus, the characterization of the midgut of B. morio supported an ecto-endoperitrophic circulation, contributing to a better understanding of the digestive process in this bee.