Evidence of Repeated and Independent Saltational Evolution in a Peculiar Genus of Sphinx Moths (Proserpinus: Sphingidae)

Background

Saltational evolution in which a particular lineage undergoes relatively rapid, significant, and unparalleled change as compared with its closest relatives is rarely invoked as an alternative model to the dominant paradigm of gradualistic evolution. Identifying saltational events is an important first-step in assessing the importance of this discontinuous model in generating evolutionary novelty. We offer evidence for three independent instances of saltational evolution in a charismatic moth genus with only eight species.

Methodology/Principal Findings

Maximum parsimony, maximum likelihood and Bayesian search criteria offered congruent, well supported phylogenies based on 1,965 base pairs of DNA sequence using the mitochondrial gene cytochrome oxidase subunit I, and the nuclear genes elongation factor-1 alpha and wingless. Using a comparative methods approach, we examined three taxa exhibiting novelty in the form of Batesian mimicry, host plant shift, and dramatic physiological differences in light of the phylogenetic data. All three traits appear to have evolved relatively rapidly and independently in three different species of Proserpinus. Each saltational species exhibits a markedly different and discrete example of discontinuous trait evolution while remaining canalized for other typical traits shared by the rest of the genus. All three saltational taxa show insignificantly different levels of overall genetic change as compared with their congeners, implying that their divergence is targeted to particular traits and not genome-wide.

Conclusions/Significance

Such rapid evolution of novel traits in individual species suggests that the pace of evolution can be quick, dramatic, and isolated—even on the species level. These results may be applicable to other groups in which specific taxa have generated pronounced evolutionary novelty. Genetic mechanisms and methods for assessing such relatively rapid changes are postulated.     

A trypsin inhibitor from <Emphasis Type="Italic">Cassia obtusifolia</Emphasis> seeds: isolation,characterization and activity against <Emphasis Type="Italic">Pieris rapae</Emphasis>

A trypsin inhibitor was isolated from Cassia obtusifolia by ammonium sulfate precipitation, Sepharose 4B-trypsin affinity and Sephadex G-75 chromatography. The inhibitor consisted of a single polypeptide chain with a molecular mass of 19, 812.55 Da. It was stable from pH 2 to 12 for 24 h, whereas it was unstable either above 70°C for 10 min or under reduced conditions. The inhibitor, which inhibited trypsin activity with an apparent Ki of 0.3 μM, had one reactive site involving a lysine residue. The native inhibitor was resistant to pepsin digestion, whereas the heated inhibitor produced 40% degree of susceptibility. The disulfide linkage and lysine residue were important in maintaining its conformation. Partial amino acid sequence of the purified protein showed a high degree of homology with various members of the Kunitz inhibitor family. Moreover, the inhibitor showed significant inhibitory activity against trypsin-like proteases present in the larval midgut on Pieris rapae and could suppress the growth of larvae.     

A novel mutation in the SCN5A gene is associated with Brugada syndrome

Brugada syndrome (BS) is an inherited cardiac disorder associated with a high risk of sudden cardiac death and is caused by mutations in the SCN5A gene encoding the cardiac sodium channel alpha-subunit (Na(v)1.5). The aim of this study was to identify the genetic cause of familial BS and characterize the electrophysiological properties of a novel SCN5A mutation (W1191X). Four families and one patient with BS were screened for SCN5A mutations by PCR and direct sequencing. Wild-type (WT) and mutant Na(v)1.5 channels were expressed in tsA201 cells, and the sodium currents (I(Na)) were analyzed using the whole-cell patch-clamp technique. A novel mutation, W1191X, was identified in a family with BS. Expression of the WT or the mutant channel (Na(v)1.5/W1191X) co-transfected with the beta(1)-subunit in tsA201 cells resulted in a loss of function of Na(v)1.5 channels. While voltage-clamp recordings of the WT channel showed a distinct acceleration of Na(v)1.5 activation and fast inactivation kinetics, the Na(v)1.5/W1191X mutant failed to generate any currents. Co-expression of the WT channel and the mutant channel resulted in a 50% reduction in I(Na). No effect on activation and inactivation were observed with this heterozygous expression. The W1191X mutation is associated with BS and resulted in the loss of function of the cardiac sodium channel.     

Gene selection via the BAHSIC family of algorithms

MOTIVATION: Identifying significant genes among thousands of sequences on a microarray is a central challenge for cancer research in bioinformatics. The ultimate goal is to detect the genes that are involved in disease outbreak and progression. A multitude of methods have been proposed for this task of feature selection, yet the selected gene lists differ greatly between different methods. To accomplish biologically meaningful gene selection from microarray data, we have to understand the theoretical connections and the differences between these methods. In this article, we define a kernel-based framework for feature selection based on the Hilbert-Schmidt independence criterion and backward elimination, called BAHSIC. We show that several well-known feature selectors are instances of BAHSIC, thereby clarifying their relationship. Furthermore, by choosing a different kernel, BAHSIC allows us to easily define novel feature selection algorithms. As a further advantage, feature selection via BAHSIC works directly on multiclass problems. RESULTS: In a broad experimental evaluation, the members of the BAHSIC family reach high levels of accuracy and robustness when compared to other feature selection techniques. Experiments show that features selected with a linear kernel provide the best classification performance in general, but if strong non-linearities are present in the data then non-linear kernels can be more suitable. AVAILABILITY: Accompanying homepage is http://www.dbs.ifi.lmu.de/~borgward/BAHSIC. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.     

High reinforcing efficacy of nicotine in non-human primates

Although tobacco appears highly addictive in humans, there has been persistent controversy about the ability of its psychoactive ingredient nicotine to induce self-administration behavior in laboratory animals, bringing into question nicotine's role in reinforcing tobacco smoking. Because of ethical difficulties in inducing nicotine dependence in na?ve human subjects, we explored reinforcing effects of nicotine in experimentally-naive non-human primates given access to nicotine for periods of time up to two years. Five squirrel monkeys with no experimental history were allowed to intravenously self-administer nicotine by pressing one of two levers. The number of presses on the active lever needed to obtain each injection was fixed (fixed-ratio schedule) or increased progressively with successive injections during the session (progressive-ratio schedule), allowing evaluation of both reinforcing and motivational effects of nicotine under conditions of increasing response cost. Over time, a progressive shift toward high rates of responding on the active lever, but not the inactive lever, developed. The monkeys' behavior was clearly directed toward nicotine self-administration, rather than presentation of environmental stimuli associated with nicotine injection. Both schedules of reinforcement revealed a high motivation to self-administer nicotine, with monkeys continuing to press the lever when up to 600 lever-presses were needed for each injection of nicotine. Thus, nicotine, by itself, in the absence of behavioral or drug-exposure history, is a robust and highly effective reinforcer of drug-taking behavior in a non-human primate model predictive of human behavior. This supports the use of nicotinic ligands for the treatment of smokers, and this novel preclinical model offers opportunities to test future medications for the treatment of nicotine dependence.     

The effects of cutting and herbicide treatment on Pteridium aquilinum encroachment

Abstract. Pteridium aquilinum (bracken) encroachment is an important factor in the loss of certain habitats in the United Kingdom. However, no information exists as to whether prevention of encroachment is a cost‐effective strategy for Pteridium management. Conventional methods for the control of Pteridium (cutting, asulam application) were tested at one site (Levisham) to quantify their ability to prevent or delay encroachment and to affect the vigour of the Pteridium at the edge of the stand. The effects of encroachment and asulam application on the vegetation present were monitored at a second site (Ramsley), where techniques commonly used for moorland restoration were employed in combination with asulam application. Cutting once per year or a single application of asulam delayed the advance of the Pteridium front. At Levisham, the untreated front advanced 2.7 m in 5 yr, while in the same period the cut front advanced 0.88 m and the sprayed front was 1.5 m behind its initial position. At Ramsley, the untreated front invaded 1.8 m in 5 yr, and the sprayed front was again 1.5 m behind its starting position. Both spraying and cutting reduced frond biomass, frond cover and rhizome biomass. Herbicide spraying prevented the loss of Calluna vulgaris, though the restoration treatments had little effect. The merits of a balanced targeting of control on encroaching fronts or Pteridium at the stand level are discussed for different situations.     

Role of dual-site phospholamban phosphorylation in intermittent hypoxia-induced cardioprotection against ischemia-reperfusion injury

Cardioprotection by intermittent high-altitude (IHA) hypoxia against ischemia-reperfusion (I/R) injury is associated with Ca(2+) overload reduction. Phospholamban (PLB) phosphorylation relieves cardiac sarcoplasmic reticulum (SR) Ca(2+)-pump ATPase, a critical regulator in intracellular Ca(2+) cycling, from inhibition. To test the hypothesis that IHA hypoxia increases PLB phosphorylation and that such an effect plays a role in cardioprotection, we compared the time-dependent changes in the PLB phosphorylation at Ser(16) (PKA site) and Thr(17) (CaMKII site) in perfused normoxic rat hearts with those in IHA hypoxic rat hearts submitted to 30-min ischemia (I30) followed by 30-min reperfusion (R30). IHA hypoxia improved postischemic contractile recovery, reduced the maximum extent of ischemic contracture, and attenuated I/R-induced depression in Ca(2+)-pump ATPase activity. Although the PLB protein levels remained constant during I/R in both groups, Ser(16) phosphorylation increased at I30 and 1 min of reperfusion (R1) but decreased at R30 in normoxic hearts. IHA hypoxia upregulated the increase further at I30 and R1. Thr(17) phosphorylation decreased at I30, R1, and R30 in normoxic hearts, but IHA hypoxia attenuated the depression at R1 and R30. Moreover, PKA inhibitor H89 abolished IHA hypoxia-induced increase in Ser(16) phosphorylation, Ca(2+)-pump ATPase activity, and the recovery of cardiac performance after ischemia. CaMKII inhibitor KN-93 also abolished the beneficial effects of IHA hypoxia on Thr(17) phosphorylation, Ca(2+)-pump ATPase activity, and the postischemic contractile recovery. These findings indicate that IHA hypoxia mitigates I/R-induced depression in SR Ca(2+)-pump ATPase activity by upregulating dual-site PLB phosphorylation, which may consequently contribute to IHA hypoxia-induced cardioprotection against I/R injury.     

Molecular characterization of the malaria vector Anopheles gambiae s.s. in Madagascar

Abstract.  Anopheles gambiae s.s. Giles (Diptera: Culicidae), the primary African malaria vector, has been characterized at the subspecies level in Madagascar, where only the molecular form S and haplotype gIA occur. The haplotype gIC proposed by other authors was not observed amongst the 35 mosquito genomes sequenced. These S/gIA characteristics are also found on the Comoros archipelago and in continental Africa.     

Lodopyridones B and C from a marine sediment-derived bacterium Saccharomonospora sp.

HPLC-UV guided isolation of the culture broth of a marine bacterium Saccharomonospora sp. CNQ-490 has led to the isolation of two new natural products, lodopyridones B and C (1 and 2) along with the previously reported lodopyridone A (3). Their chemical structures were established from the interpretation of 2D NMR spectroscopic data and the comparison of NMR data with the lodopyridone A (3). Lodopyridones B and C (1 and 2) possess the thiazole, and chloroquinoline groups which are characteristic features of these molecules. Lodopyridones A–C show weak inhibitory activities on the β-site amyloid precursor protein cleaving enzyme 1 (BACE1).