Phylogenetic relationships within an endemic group of Malagasy 'assassin spiders' (Araneae, Archaeidae): ancestral character reconstruction, convergent evolution and biogeography

The phylogenetic relationships in an endemic group of Malagasy 'assassin spiders' (Araneae, Archaeidae: Eriauchenius) called the gracilicollis group, are inferred from mitochondrial 12S, 16S and COI DNA sequence data. Archaeid spiders of Madagascar have evolved varying degrees of elongation in the cephalic area. These molecular data support the monophyly of the gracilicollis group. The evolution of the cephalic area is examined by performing an ancestral character reconstruction on this character, which reveals that the cephalic area is elongating independently. The biogeography of the gracilicollis group reveals an east-west split of the clade on Madagascar.     

Hepatocyte growth factor enhances IL-1β stimulated IL-8 secretion by Caco-2 epithelial cells

Hepatocyte growth factor (HGF) can induce proliferation and migration of intestinal epithelial cells and has also been shown to be important in wound healing of inflamed mucosal tissues. HGF is known to be expressed along with interleukin-1 (IL-1) by inflamed mucosal tissues, yet the effect of HGF on IL-1-induced proinflammatory cytokine responses by colonic epithelial cells is unknown. In this report, we have examined the effect of HGF on IL-1-induced secretion of IL-8 by the Caco-2 colonic epithelial cell line. HGF stimulation alone had no effect on the secretion of IL-8 by the Caco-2 cells. However, culture of the cells with HGF and suboptimal levels of IL-1 resulted in a significant enhancement of IL-8 secretion compared to cells cultured with IL-1 alone. A similar effect was seen with HGF and IL-1 simulation of monocyte chemoattractant protein-1 secretion by the rat IEC-6 intestinal epithelial cell line. The enhancing effect of HGF was seen regardless of whether the culture medium contained serum or not. Simultaneous stimulation with HGF and IL-1 was required for the enhancing effect as cells pretreated with HGF for 24 h and then stimulated with IL-1 alone secreted IL-8 levels similar to that of cells stimulated with IL-1 alone. These results suggest that in addition to wound healing, HGF may play a role in the IL-1-induced chemokine response of epithelial cells in inflamed mucosal tissues.     

The consequences of surrendering a degree of freedom to the participant in a contingency assessment task

Many studies of contingency judgments have used a task in which, on each trial, the participant is free either to respond or not to respond, and an outcome may, or may not, be presented. Typically, the experimenter specifies a nominal value for the contingency between responding and outcome, but the actual values of a variety of variables experienced by a particular participant depend on that participant's frequency of responding. The results of computer simulations of various strategies for implementing the contingency manipulation, and the results of an experiment, indicate that the same nominal contingency value will lead to considerable variability in the actual contingency experienced by participants. Moreover, nominal contingency manipulations are confounded with the probability that the subject experiences an outcome. While researchers might be aware of these issues, not enough attention has been paid to their potential impact.     

Assessment of genetic stability of the germplasm lines of medicinal plant <Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi (Huang-qin) in long-term,in vitro maintained cultures

An approach of combining flow cytometry (FCM) analysis with morphological and chemical profiling was used to assess the genetic stability and bioactive compound diversity in a Scutellaria baicalensis Georgi (Huang-qin) germplasm collection that was clonally maintained in in vitro for a period of over 6 years. Based on the FCM analysis of nuclei samples from young shoots, the nuclear DNA content of S. baicalensis was calculated as 0.84 pg/2C. FCM analysis showed no significant variation in the nuclear DNA contents and ploidy levels in the long-term in vitro maintained germplasm lines. Germplasm lines, acclimatized to ex vitro conditions, exhibited distinctive plant growth and bioactive compound production capacities. The high level of genetic stability observed in in vitro maintained S. baicalensis lines opens up a variety of opportunities such as allowing long-term aseptic preservation and easy distribution of well-characterized germplasm lines of this medicinal plant species. This study represents a novel approach for continuous maintenance, monitoring, and production of medicinal plant tissues with specific chemistry.     

Neuregulin-1 enhances depolarization-induced GABA release

Neuregulin-1 (NRG1), a regulator of neural development, has been shown to regulate neurotransmission at excitatory synapses. Although ErbB4, a key NRG1 receptor, is expressed in glutamic acid decarboxylase (GAD)-positive neurons, little is known about its role in GABAergic transmission. We show that ErbB4 is localized at GABAergic terminals of the prefrontal cortex. Our data indicate a role of NRG1, both endogenous and exogenous, in regulation of GABAergic transmission. This effect was blocked by inhibition or mutation of ErbB4, suggesting the involvement of ErbB4. Together, these results indicate that NRG1 regulates GABAergic transmission via presynaptic ErbB4 receptors, identifying a novel function of NRG1. Because both NRG1 and ErbB4 have emerged as susceptibility genes of schizophrenia, these observations may suggest a mechanism for abnormal GABAergic neurotransmission in this disorder.     

The differential response of human dendritic cells to live and killed Neisseria meningitidis

There is currently no effective vaccine for Neisseria meningitidis (Nm) serogroup B. Generation of optimal immune responses to meningococci could be achieved by targeting meningococcal antigens to human dendritic cells (DCs). Recent studies have shown that diverse DC responses and subsequent generation of protective immunity can be observed if the microbes are viable or killed. This is important because the host is likely to be exposed to both live and killed bacteria during natural infection. There are currently few data on comparative DC responses to live and killed meningococci. We show here that exposure of human DC to live meningococci does not result in a typical maturation response, as determined by the failure to upregulate CD40, CD86, HLA-DR and HLA-Class I. Despite this, live meningococci were potent inducers of IL-12 and IL-10, although the ratios of these cytokines differed from those to killed organisms. Our data also suggest that enhanced phagocytosis of killed organisms compared with live may be responsible for the differential cytokine responses, involving an autocrine IL-10-dependent mechanism. The consequences of these findings upon the effectiveness of antigen presentation and T-cell responses are currently under investigation.     

A decision support tool for integrated fisheries bycatch management

Reviews in Fish Biology and Fisheries - Participatory decision tools enable stakeholders to reconcile conflicting natural resources management objectives. Fisheries targeting highly productive...