Recent horizontal transfer of a mariner transposable element among and between Diptera and Neuroptera

Transposable elements of the mariner family are widespread among insects and other invertebrates, and initial analyses of their relationships indicated frequent occurrence of horizontal transfers between hosts. A specific PCR assay was used to screen for additional members of the irritans subfamily of mariners in more than 400 arthropod species. Phylogenetic analysis of cloned PCR fragments indicated that relatively recent horizontal transfers had occurred into the lineages of a fruit fly Drosophila ananassae, the horn fly Haematobia irritans, the African malaria vector mosquito Anopheles gambiae, and a green lacewing Chrysoperla plorabunda. Genomic dot-blot analysis revealed that the copy number in these species varies widely, from about 17,000 copies in the horn fly to three copies in D. ananassae. Multiple copies were sequenced from genomic clones from each of these species and four others with related elements. These sequences confirmed the PCR results, revealing extremely similar elements in each of these four species (greater than 88% DNA and 95% amino acid identity). In particular, the consensus sequence of the transposase gene of the horn fly elements differs by just two base pairs out of 1,044 from that of the lacewing elements. The mosquito lineage has diverged from the other Diptera for over 200 Myr, and the neuropteran last shared a common ancestor with them more than 265 Myr ago, so this high similarity implies that these transposons recently transferred horizontally into each lineage. Their presence in only the closest relatives in at least the lacewing lineage supports this hypothesis. Such horizontal transfers provide an explanation for the evolutionary persistence and widespread distribution of mariner transposons. We propose that the ability to transfer horizontally to new hosts before extinction by mutation in the current host constitutes the primary selective constraint maintaining the sequence conservation of mariners and perhaps other DNA-mediated elements.      

Decrease of hepatic catalase level by treatment with diallyl sulfide and garlic homogenates in rats and mice

Diallyl sulfide (DAS) is a flavor compound derived from garlic and is active in the inhibition of chemically induced cytotoxicity and carcinogenicity in animal models. This study was conducted to examine the effects of the treatment of DAS and garlic homogenates on the activities of catalase, glutathione peroxidase, and superoxide dismutase. Male Sprague-Dawley rats were treated with DAS i.g. at daily doses of 50 or 200 mg/kg for 8 days, causing the hepatic catalase activity to decrease by 55 and 95%, respectively. Such a decrease in hepatic catalase activity was also observed when the DAS treatment was extended to 29 days. Western blot analysis showed that the DAS treatments resulted in corresponding decreases in the liver catalase protein level. No significant change in the catalase activity in the kidney, lung, and brain was observed with the treatments, but a slight decrease in heart catalase activity was observed. These treatments did not cause significant changes in superoxide dismutase and glutathione peroxidase activities in these tissues. Treatment with DAS at a daily dose of 200 mg/kg for 1-7 days resulted in a gradual decrease in the liver catalase activity to 5% of the control level, but it did not decrease the erythrocyte catalase activity. Treatment of rats with fresh garlic homogenates (2 or 4 g/kg, i.g., daily for 7 days) caused a 35% decrease in liver catalase activity. A/J mice treated with DAS and garlic homogenates also showed a decrease in the liver catalase activity. Diallyl sulfone (DASO2), a DAS metabolite, however, did not effectively decrease catalase activity in mice. The catalase activity was not inhibited by either DAS or DASO2 in vitro. The present results demonstrate that treatment with DAS and garlic homogenates decrease the hepatic catalase level in rats and mice.     

Effects of plant height and row spacing on kenaf forage potential with multiple harvests

Kenaf (Hibiscus cannabinus L.) forage potential can be enhanced through its regrowth capacity and higher production in narrow rows. A field experiment was conducted in Matamoros, Coahuila, Mexico, during 2 growing seasons (2004 and 2005) to study the effects of plant height and row spacing on kenaf forage potential with multiple harvests. This study evaluated the effects of (1) 2 plant heights at cutting (1.0-1.2 m and 1.8-2.0 m) and (2) 4 inter row spacings (0.19, 0.38, 0.57 and 0.76 m) using a 2 x 4 factorial arrangement of treatments in a completely randomized block design with 4 replications. Dry matter (DM) and crude protein (CP) yields, DM partitioning, neutral detergent fiber (NDF) and CP concentrations were determined. Heights at cutting × row spacing interactions were not significant for the monitored variables (p>0.05). Kenaf response to treatments was only relevant for main effects (p≤0.05). Row spacing and plant height affected DM and CP yields (p≤0.05), whereas only plant height affected chemical composition and DM partitioning (p≤0.05). Dry matter (17.0%-26.0%), and CP (12.4%-15.6%) yields were higher (p≤0.05) when plant heights had reached 1.8 to 2.0 m. Row spacing reduction from 0.76 m to 0.38 and 0.19 m increased DM yield (20.4-33.4%) and CP yield (24.2-38.5%) (p≤0.05). Kenaf forage potential increases when planted in narrow rows and harvested 2 or 3 times during the growing season.     

Characterization of two heparan sulphate-binding sites in the mycobacterial adhesin Hlp

Background  

The histone-like Hlp protein is emerging as a key component in mycobacterial pathogenesis, being involved in the initial events of host colonization by interacting with laminin and glycosaminoglycans (GAGs). In the present study, nuclear magnetic resonance (NMR) was used to map the binding site(s) of Hlp to heparan sulfate and identify the nature of the amino acid residues directly involved in this interaction.     

Activity evaluation of cocoa pod borer sex pheromone in cacao fields

The previously identified female sex pheromone of cocoa pod borer, Conopomorpha cramerella, was re-evaluated for its attractive activity in different field conditions. It was found that lures containing 100-mug of synthetic sex pheromone blend, (E,Z,Z)- and (E,E,Z)-4,6,10-hexadecatrienyl acetates, and the corresponding alcohols in a ratio of 40:60:4:6 in a polyethylene vial attracted male C. cramerella moths in Sabah and peninsular Malaysia and in Sumatra and Sulawesi, Indonesia, suggesting that the same pheromone strain existed in a wide stretch of the Indo-Malayan archipelago. Of the three kinds of trap designs tested, the Delta traps were more effective than Pherocon V scale traps. Male captures were not significantly different among traps baited with 100-, 300-, or 1,000-mug doses of sex pheromone. A release rate study of pheromone formulation conducted in the laboratory showed that volatile active ingredients were desorbed from polyethylene vials following first-order kinetics, which indicates a satisfactory "half-life time" of a 100-mug loading is approximately 6 wk under laboratory conditions. A satisfactory attractiveness of the lure with a 100-mug loading was approximately 1-2 mo in the fields.     

Identification of Peptide Leads to Inhibit Hepatitis C Virus: Inhibitory Effect of Plectasin Peptide Against Hepatitis C Serine Protease

The emerging of hepatitis C virus (HCV) resistant strains has been considered as a main drawback of the available drugs. Since HCV has a large inactive surface, we would like to hypothesis that the mutation occur in HCV is minimal and causing less resistance against inhibition. In this study, a short peptide inhibitor of HCV namely plectasin was identified by HCV NS3-4A serine protease assay. Plectasin peptide showed considerable inhibition against HCV NS3-4A serine protease. Enzymatic activity of the recombinant NS3-4Apro was analysed by fluorescence release from several fluorogenic peptide substrates which resembling the dibasic cleavage site sequences of the flavivirus polyprotein precursor. Of all amc-labelled peptides, Pyr-RTKR-amc was the most efficiently cleaved substrate with the lowest Km value of 20 µM. The kinetic assay showed that plectasin peptide inhibited NS3-4Apro activity with an IC₅₀ value of 4.3 μM compared to the aprotinin as a standard proteases inhibitor with an IC₅₀ of 6.1 μM. From the results, plectasin peptide also demonstrated a dose-dependent inhibition of HCV replication with a considerable reduction in RLuc activity at 15 µM using HCV replicon- containing Huh-7 cells. Our study has identified a unique natural peptide that can be used to highlight novel structures for the development of drug derivatives with high efficacy of HCV NS3-4A protease inhibitors.     

ImageParser: a tool for finite element generation from three-dimensional medical images

Background

The finite element method (FEM) is a powerful mathematical tool to simulate and visualize the mechanical deformation of tissues and organs during medical examinations or interventions. It is yet a challenge to build up an FEM mesh directly from a volumetric image partially because the regions (or structures) of interest (ROIs) may be irregular and fuzzy.

Methods

A software package, ImageParser, is developed to generate an FEM mesh from 3-D tomographic medical images. This software uses a semi-automatic method to detect ROIs from the context of image including neighboring tissues and organs, completes segmentation of different tissues, and meshes the organ into elements.

Results

The ImageParser is shown to build up an FEM model for simulating the mechanical responses of the breast based on 3-D CT images. The breast is compressed by two plate paddles under an overall displacement as large as 20% of the initial distance between the paddles. The strain and tangential Young's modulus distributions are specified for the biomechanical analysis of breast tissues.

Conclusion

The ImageParser can successfully exact the geometry of ROIs from a complex medical image and generate the FEM mesh with customer-defined segmentation information.

     

Low rates of clinical restenosis with the new flexible stainless steel tube intracoronary stent: the R Stent. A six-month safety and feasibility study

BACKGROUND: Coronary stents have been used with increasing frequency and in increasingly complex coronary lesions for the treatment of symptomatic coronary artery disease. A new stainless steel coronary stent, the R Stent, has been designed to provide maximum flexibility for tracking and high radial strength post-deployment. AIMS: To assess the safety and feasibility of the R Stent in patients with coronary artery disease. Specific objectives were to assess the R Stent's deployment success, angiographic and procedural success (< 20% residual stenosis and TIMI 3 flow), safety (absence of complications), 30-day and six-month clinical follow-up. METHODS: Between April 1998 and January 1999, stent deployment was attempted in 36 lesions in 30 patients with stable (43%) or unstable (57%) angina pectoris and 29/36 of the lesions were anatomically complex. Treated lesions were in the LAD (n = 15), RCA (n = 13) or LCX (n = 8). RESULTS: Stent deployment was achieved in 97% with one crossing failure in a patient with a long, calcified, proximal LAD lesion. After the procedure, patients were scheduled for one- and six-month clinical follow-up. One patient experienced a non-Q-wave myocardial infarction in hospital. At one month, there were no additional complications. Only one patient experienced recurrence of angina (CCS class 2) within the 30 days. At six-month follow-up, one sudden death had occurred. Three (10%) patients had anginal complaints, one of them received target lesion repeat PTCA. All other patients (87%) were event- and angina-free. CONCLUSION: This first clinical experience with the R Stent shows acceptable feasibility and safety with good long-term clinical results.