Explaining differential herbivory in sun and shade: the case of Aristotelia chilensis saplings

Differential herbivory in contrasting environments is commonly explained by differences in plant traits. When several plant traits are considered, separate correlation analyses between herbivory and candidate traits are typically conducted. This makes it difficult to discern which trait best explain the herbivory patterns, or to avoid spurious inferences due to correlated characters. Aristotelia chilensis saplings sustain greater herbivory in shaded environments than in open habitats. We measured alkaloids, phenolics, trichomes, leaf thickness and water content in the same plants sampled for herbivory. We conducted a multiple regression analysis to estimate the relationship between herbivory and each plant trait accounting for the effect of correlated traits, thus identifying which trait(s) better explain(s) the differential herbivory on A. chilensis. We also estimated insect abundance in both light environments. Palatability bioassays tested whether leaf consumption by the main herbivore on A. chilensis was consistent with field herbivory patterns. Overall insect abundance was similar in open and shaded environments. While saplings in open environments had thicker leaves, lower leaf water content, and higher concentration of alkaloids and phenolics, no difference in trichome density was detected. The multiple regression analysis showed that leaf thickness was the only trait significantly associated with herbivory. Thicker leaves received less damage by herbivores. Sawfly larvae consumed more leaf tissue when fed on shade leaves. This result is consistent with field herbivory and, together with results of insect abundance, renders unlikely that the differential herbivory in A. chilensis was due to greater herbivory pressure in open habitats.     

Secretion and properties of a hybrid Kluyveromyces lactis-Aspergillus niger β-galactosidase

Background  

The β-galactosidase from Kluyveromyces lactis is a protein of outstanding biotechnological interest in the food industry and milk whey reutilization. However, due to its intracellular nature, its industrial production is limited by the high cost associated to extraction and downstream processing.     

Rhesus macaque polyclonal and monoclonal antibodies inhibit simian immunodeficiency virus in the presence of human or autologous rhesus effector cells

Although antibodies can prevent or modulate lentivirus infections in nonhuman primates, the biological functions of antibody responsible for such effects are not known. We sought to determine the role of antibody-dependent cell-mediated virus inhibition (ADCVI), an antibody function that inhibits virus yield from infected cells in the presence of Fc receptor-bearing effector cells, in preventing or controlling SIVmac251 infection in rhesus macaques (Macaca mulatta). Using CEMx174 cells infected with simian immunodeficiency virus mac251 (SIVmac251), both polyclonal and monoclonal anti-SIV antibodies were capable of potent virus inhibition in the presence of human peripheral blood mononuclear cell (PBMC) effector cells. In the absence of effector cells, virus inhibition was generally very poor. PBMCs from healthy rhesus macaques were also capable of mediating virus inhibition either against SIVmac251-infected CEMx174 cells or against infected, autologous rhesus target cells. We identified both CD14(+) cells and, to a lesser extent, CD8(+) cells as the effector cell population in the rhesus PBMCs. Finally, pooled, nonneutralizing SIV-antibody-positive serum, shown in a previous study to prevent infection of neonatal macaques after oral SIVmac251 challenge, had potent virus-inhibitory activity in the presence of effector cells; intact immunoglobulin G, rather than F(ab')(2), was required for such activity. This is the first demonstration of both humoral and cellular ADCVI functions in the macaque-SIV model. ADCVI activity in nonneutralizing serum that prevents SIV infection suggests that ADCVI may be a protective immune function. Finally, our data underscore the potential importance of Fc-Fc receptor interactions in mediating biological activities of antibody.     

Gastroprotective and ulcer healing effect of ferruginol in mice and rats: assessment of its mechanism of action using in vitro models

The gastroprotective activity of the diterpene ferruginol isolated from Prumnopitys andina wood and bark was determined on HCl/EtOH-induced gastric lesions in mice. The effect of the compound on the healing of subacute gastric lesions in rats was also studied. The mode of action of the diterpene was assessed using human gastric epithelial cells (AGS) and MRC-5 fibroblasts. The effect of ferruginol on the prostaglandin E2 content, protection against sodium taurocholate induced-damage and reduced glutathione content was evaluated on AGS cells as well as on the growth of AGS and fibroblast cultures. The free radical scavenging effect of ferruginol was assessed by the 1,1-diphenyl-2-picryl-hydrazil radical and superoxide anion assays. The effect of ferruginol on human erythrocyte membrane lipoperoxidation was determined. The cytotoxicity of the compound was assessed by means of the neutral red uptake. At 25 mg/kg, ferruginol inhibited the appearance of gastric lesions by 60% showing similar effects than lansoprazole at 20 mg/kg. Additionally, the compound displayed a significant ulcer healing activity in rats at 25 and 50 mg/kg with curative ratios of 36.0% and 92.5%, respectively, while the reference compound ranitidine at 50 mg/kg showed a curative ratio of 79.6%. At 6 and 12 microM, ferruginol increased significantly the prostaglandin E2 content. A strong inhibition of lipoperoxidation was found (IC50: 1.4 microM), but no effect was observed on the sodium taurocholate induced-damage or reduced glutathione content. Ferruginol stimulated cell proliferation at 1-2 microM in AGS cells and at 4-8 microM in fibroblasts, with cytotoxicities (IC50) of 24 and 26 microM, respectively. Our results support that ferruginol acts as gastroprotective increasing the PGs content, protecting the cells against lipid peroxidation and improving the gastric ulcer healing by a stimulating effect on the cell proliferation. These findings encourage further pharmacological studies of ferruginol as a potential new anti-ulcerogenic drug.     

Functional genetic analysis of rhesus cytomegalovirus: Rh01 is an epithelial cell tropism factor

Rhesus cytomegalovirus (RhCMV) is an emerging model for human cytomegalovirus (HCMV) pathogenesis that facilitates experimental CMV infection of a natural primate host closely related to humans. We have generated a library of RhCMV mutants with lesions in genes whose HCMV orthologues have been characterized as nonessential for replication in human fibroblasts, and we characterized their replication in rhesus fibroblasts and epithelial cells. The RhCMV mutants grew well in fibroblasts, as predicted by earlier studies with HCMV. However, mutations in four genes caused replication defects in rhesus retinal pigment epithelial cells: Rh01 (an HCMV TRL1 orthologue), Rh159 (HCMV UL148), Rh160 (HCMV UL132), and Rh203 (HCMV US22). Growth of the Rh01-deficient mutant was examined in detail. After entry into epithelial cells, the mutant expressed representative viral proteins, accumulated viral DNA, and generated infectious virus, but it failed to spread efficiently. We conclude that Rh01 is a cell tropism determinant that has the potential to dramatically affect virus spread and pathogenesis.     

Pigment epithelium-derived factor binds to hyaluronan. Mapping of a hyaluronan binding site

Pigment epithelium-derived factor (PEDF) is a multifunctional serpin with antitumorigenic, antimetastatic, and differentiating activities. PEDF is found within tissues rich in the glycosaminoglycan hyaluronan (HA), and its amino acid sequence contains putative HA-binding motifs. We show that PEDF coprecipitation with glycosaminoglycans in media conditioned by human retinoblastoma Y-79 cells decreased after pretreatments with hyaluronidase, implying an association between HA and PEDF. Direct binding of human recombinant PEDF to highly purified HA was demonstrated by coprecipitation in the presence of cetylpyridinium chloride. Binding of PEDF to HA was concentration-dependent and saturable. The PEDF-HA interactions were sensitive to increasing NaCl concentrations, indicating an ionic nature of these interactions and having affinity higher than PEDF-heparin. Competition assays showed that PEDF can bind heparin and HA simultaneously. PEDF chemically modified with fluorescein retained the capacity for interacting with HA but lacked heparin affinity, suggesting one or more distinct HA-binding regions on PEDF. The HA-binding region was examined by site-directed mutagenesis. Single-point and cumulative alterations at basic residues within the putative HA-binding motif K189A/K191A/R194A/K197A drastically reduced the HA-binding activity without affecting heparin- or collagen I binding of PEDF. Cumulative alterations at sites critical for heparin binding (K146A/K147A/R149A) decreased HA affinity but not collagen I binding. Thus these clusters of basic residues (BXBXXBXXB and BX3AB2XB motifs) in PEDF are functional regions for binding HA. In the spatial PEDF structure they are located in distinct areas away from the collagen-binding site. The HA-binding activity of PEDF may contribute to deposition in the extracellular matrix and to its reported antitumor/antimetastatic effects.     

The dentition of Manidens condorensis (Ornithischia; Heterodontosauridae) from the Jurassic Cañadón Asfalto Formation of Patagonia: morphology,heterodonty and the use of statistical methods for identifying isolated teeth

The recently described Manidens condorensis is one of the most completely known taxa of the family Heterodontosauridae from the southern landmasses. However, some dental aspects are not well known due to preservational problems in the type material. This contribution reports new isolated teeth found in the Cañadón Asfalto Formation (Early-Middle Jurassic). These teeth are referred to Manidens condorensis based on the presence of autapomorphic characters of the unusual dentition of this taxon, such as the highly asymmetric tooth crowns and small crenulations on each denticles. The isolated crowns are well preserved and reveal the presence of undescribed and new autapomorphical features, including apical and basal wear facets on the occlusal surface of isolated crowns and a wear surface also in the caniniform tooth. We carried out statistical analyses (including morphogeometrical and discriminant analyses), using the holotype crowns as a morphological starting point, for characterising shape variation of the crowns along the toothrow and for identifying the position of isolated crowns. These analyses allow defining morphological regions within the postcaniniform toothrow and produce a metrically based discriminant function to predict the hypothetical position of future discoveries, providing a methodological framework that could be applied to other extinct heterodont dinosaurs.     

Pain Facilitation Brain Regions Activated by Nalbuphine Are Revealed by Pharmacological fMRI

Nalbuphine, an agonist-antagonist kappa-opioid, produces brief analgesia followed by enhanced pain/hyperalgesia in male postsurgical patients. However, it produces profound analgesia without pain enhancement when co-administration with low dose naloxone. To examine the effect of nalbuphine or nalbuphine plus naloxone on activity in brain regions that may explain these differences, we employed pharmacological magnetic resonance imaging (phMRI) in a double blind cross-over study with 13 healthy male volunteers. In separate imaging sessions subjects were administered nalbuphine (5 mg/70 kg) preceded by either saline (Sal-Nalb) or naloxone 0.4 mg (Nalox-Nalb). Blood oxygen level-dependent (BOLD) activation maps followed by contrast and connectivity analyses revealed marked differences. Sal-Nalb produced significantly increased activity in 60 brain regions and decreased activity in 9; in contrast, Nalox-Nalb activated only 14 regions and deactivated only 3. Nalbuphine, like morphine in a previous study, attenuated activity in the inferior orbital cortex, and, like noxious stimulation, increased activity in temporal cortex, insula, pulvinar, caudate, and pons. Co-administration/pretreatment of naloxone selectively blocked activity in pulvinar, pons and posterior insula. Nalbuphine induced functional connectivity between caudate and regions in the frontal, occipital, temporal, insular, middle cingulate cortices, and putamen; naloxone co-admistration reduced all connectivity to non-significant levels, and, like phMRI measures of morphine, increased activation in other areas (e.g., putamen). Naloxone pretreatment to nalbuphine produced changes in brain activity possess characteristics of both analgesia and algesia; naloxone selectively blocks activity in areas associated with algesia. Given these findings, we suggest that nalbuphine interacts with a pain salience system, which can modulate perceived pain intensity.     

Fibrotic response induced by angiotensin-II requires NAD(P)H oxidase-induced reactive oxygen species (ROS) in skeletal muscle cells

Fibrotic disorders are typified by excessive connective tissue and extracellular matrix (ECM) deposition that precludes normal healing processes in different tissues. Angiotensin-II (Ang-II) is involved in the fibrotic response. Several muscular dystrophies are characterized by extensive fibrosis. However, the exact role of Ang-II in skeletal muscle fibrosis is unknown. Here we show that myoblasts responded to Ang-II by increasing protein levels of connective tissue growth factor (CTGF/CCN2), collagen-III and fibronectin. These Ang-II-induced pro-fibrotic effects were mediated by AT-1 receptors. Remarkably, Ang-II induced reactive oxygen species (ROS) via a NAD(P)H oxidase-dependent mechanism, as shown by inhibition of ROS production via the NAD(P)H oxidase inhibitors diphenylene iodonium (DPI) and apocynin. This increase in ROS is critical for Ang-II-induced fibrotic effects, as indicated by the decrease in Ang-II-induced CTGF and fibronectin levels by DPI and apocynin. We also show that Ang-II-induced ROS production and fibrosis require PKC activity as indicated by the generic PKC inhibitor chelerythrine.These results strongly suggest that the fibrotic response induced by Ang-II is mediated by AT-1 receptor and requires NAD(P)H-induced ROS in skeletal muscle cells.     

Gut microbiota in nymph and adults of the giant mesquite bug (Thasus neocalifornicus) (Heteroptera: Coreidae) is dominated by Burkholderia acquired de novo every generation

The coreid bug Thasus neocalifornicus Brailovsky and Barrera, commonly known as the giant mesquite bug, is a ubiquitous insect of the southwestern United States. Both nymphs and adults are often found aggregated on mesquite trees (Prosopis spp.: Fabaceae) feeding on seedpods and plant sap. We characterized the indigenous bacterial populations of nymphs and adults of this species by using molecular and phylogenetic techniques and culturing methods. Results show that this insect's bacterial gut community has a limited diversity dominated by Burkholderia associates. Phylogenetic analysis by using 16s rRNA sequences suggests that these β-Proteobacteria are closely related to those symbionts obtained from other heteropteran midgut microbial communities but not to Burkholderia symbionts associated with other insect orders. These bacteria were absent from the eggs and were not found in all younger nymphs, suggesting that they are acquired after the insects have hatched. Rearing experiments of nymphs with potentially Burkholderia contaminated soil suggested that if this symbiont is not acquired, giant mesquite bugs experience higher mortality. Egg, whole-body DNA extractions of younger nymphs, and midgut DNA extractions of fifth-instar nymphs and adults also revealed the presence of α-Proteobacteria from the Wolbachia genus. However, this bacterium was also present in reproductive organs of adults, indicating that this symbiont is not specific to the gut.