The taxonomic status of pest species of Coptotermes in Southeast Asia: Resolving the paradox in the pest status of the termites, Coptotermes gestroi, C-havilandi and C-travians (Isoptera : Rhinotermitidae)

The taxonomic status of Coptotermes gestroi (Wasmann), C. havilandi Holmgren, C. travians (Haviland) and C. borneensis Oshima (Isoptera: Rhinotermitidae) is revised. The apparent discrepancy between the reported importance of C. havitandi in countries to which it has been introduced and the region from which it originated is shown to be due to misidentification and taxonomic confusion between C. travians, C. havilandi and C. gestroi. Based on an examination of specimens from Southeast Asia, two species are recognized, namely C. gestroi and C. travians. Coptotermes havilandi, described from imagos, is shown to be the same species as C. gestro described earlier from the soldier caste, and is designated a junior synonym. Coptotermes gestroi occurs from Assam through Burma and Thailand to Malaysia and the Indonesian archipelago, and has been introduced into other geographic regions, including parts of North and South America and the Caribbean. It is frequently found damaging wood in buildings, and is often intercepted outside its range in cargo onboard ships and sailing vessels, which is a likely mechanism for its spread to new geographical areas. Coptotermes gestroi has been misidentified in much literature as C. travians. Conversely, C. travians has been misidentified in recent literature in Peninsular Malaysia as C. havilandi and was redescribed from Borneo as C. borneensis, which is here designated a junior synonym of C. travians. It has a known distribution from Peninsular Malaysia to Borneo, and has not been found infesting wood in buildings. It is envisaged that the resolution of this taxonomic problem will enable the deployment of common pest management strategies for C. gestro the primary pest species of Coptotermes originating from Southeast Asia.

Contribution of redox status to hepatitis C virus E2 envelope protein function and antigenicity

Disulfide bonding contributes to the function and antigenicity of many viral envelope glycoproteins. We assessed here its significance for the hepatitis C virus E2 envelope protein and a counterpart deleted for hypervariable region-1 (HVR1). All 18 cysteine residues of the antigens were involved in disulfides. Chemical reduction of up to half of these disulfides was compatible with anti-E2 monoclonal antibody reaction, CD81 receptor binding, and viral entry, whereas complete reduction abrogated these properties. The addition of 5,5'-dithiobis-2-nitrobenzoic acid had no effect on viral entry. Thus, E2 function is only weakly dependent on its redox status, and cell entry does not require redox catalysts, in contrast to a number of enveloped viruses. Because E2 is a major neutralizing antibody target, we examined the effect of disulfide bonding on E2 antigenicity. We show that reduction of three disulfides, as well as deletion of HVR1, improved antibody binding for half of the patient sera tested, whereas it had no effect on the remainder. Small scale immunization of mice with reduced E2 antigens greatly improved serum reactivity with reduced forms of E2 when compared with immunization using native E2, whereas deletion of HVR1 only marginally affected the ability of the serum to bind the redox intermediates. Immunization with reduced E2 also showed an improved neutralizing antibody response, suggesting that potential epitopes are masked on the disulfide-bonded antigen and that mild reduction may increase the breadth of the antibody response. Although E2 function is surprisingly independent of its redox status, its disulfide bonds mask antigenic domains. E2 redox manipulation may contribute to improved vaccine design.

A comparison of the active surveillance of scrapie in the European Union

The abattoir and the fallen stock surveys constitute the active surveillance component aimed at improving the detection of scrapie across the European Union. Previous studies have suggested the occurrence of significant differences in the operation of the surveys across the EU. In the present study we assessed the standardisation of the surveys throughout time across the EU and identified clusters of countries with similar underlying characteristics allowing comparisons between them. In the absence of sufficient covariate information to explain the observed variability across countries, we modelled the unobserved heterogeneity by means of non-parametric distributions on the risk ratios of the fallen stock over the abattoir survey. More specifically, we used the profile likelihood method on 2003, 2004 and 2005 active surveillance data for 18 European countries on classical scrapie, and on 2004 and 2005 data for atypical scrapie separately. We extended our analyses to include the limited covariate information available, more specifically, the proportion of the adult sheep population sampled by the fallen stock survey every year. Our results show that the between-country heterogeneity dropped in 2004 and 2005 relative to that of 2003 for classical scrapie. As a consequence, the number of clusters in the last two years was also reduced indicating the gradual standardisation of the surveillance efforts across the EU. The crude analyses of the atypical data grouped all the countries in one cluster and showed non-significant gain in the detection of this type of scrapie by any of the two sources. The proportion of the population sampled by the fallen stock appeared significantly associated with our risk ratio for both types of scrapie, although in opposite directions: negative for classical and positive for atypical. The initial justification for the fallen stock, targeting a high-risk population to increase the likelihood of case finding, appears compromised for both types of scrapie in some countries.

Immunogenicity of the outer domain of a HIV-1 clade C gp120

Background: The possibility that a sub domain of a C clade HIV-1 gp120 could act as an effective immunogen was investigated. To do this, the outer domain ( OD) of gp120(CN54) was expressed and characterized in a construct marked by a re-introduced conformational epitope for MAb 2G12. The expressed sequence showed efficient epitope retention on the isolated ODCN54 suggesting authentic folding. To facilitate purification and subsequent immunogenicity ODCN54 was fused to the Fc domain of human IgGl. Mice were immunised with the resulting fusion proteins and also with gp120(CN54)-Fc and gp120 alone. Results: Fusion to Fc was found to stimulate antibody titre and Fc tagged ODCN54 was substantially more immunogenic than non-tagged gp120. Immunogenicity appeared the result of Fc facilitated antigen processing as immunisation with an Fc domain mutant that reduced binding to the FcR lead to a reduction in antibody titre when compared to the parental sequence. The breadth of the antibody response was assessed by serum reaction with five overlapping fragments of gp120(CN54) expressed as GST fusion proteins in bacteria. A predominant anti-inner domain and anti-V3C3 response was observed following immunisation with gp120(CN54)-Fc and an anti-V3C3 response to the ODCN54-Fc fusion. Conclusion: The outer domain of gp120(CN54) is correctly folded following expression as a C terminal fusion protein. Immunogenicity is substantial when targeted to antigen presenting cells but shows V3 dominance in the polyvalent response. The gp120 outer domain has potential as a candidate vaccine component.

Effects of biologically active tumour-promoting and non-promoting phorbol esters on in vivo growth of melanocytic cells

Sapintoxin A (SAP A), a naturally occurring biologically active but non-promoting phorbol ester, acts as an effective in vitro mitogen for freshly derived human melanocytes. Seven days after addition of 50 nM SAP A there was a four to fivefold increase in melanocyte number over that observed in untreated control cultures comparable to that achieved with a 50 nM concentration of 12-0-tetradecanoylphorbol 13-acetate (TPA). The fluorescent stage 2 promoter sapintoxin D (SAP D) also supported the growth of these cells, with a 50 nM dose producing an increase in cell number comparable to that observed with 200 nM TPA. Similar results were obtained with an established, but non-tumorigenic, line of murine melanocytes. The same compounds exerted a potent anti-proliferative effect against transformed melanocyte lines of murine and human origin associated with morphological alterations and an increase in melanin production consistent with induced cytodifferentiation.

Design of an active arm support for assisting arm movements

In this paper we have explored areas of application for health care manipulators and possible user groups. We have shown the steps in the design approach to the conceptual mechanism from the AAS. The future work will be measurement from properties of the muscle with the elbow parameterization test-bed to get a database to design one part of the control area from the AAS. More work on the mechanical design is required before a functional prototype can be built.

Modelling and control of Hammerstein system using B-spline approximation and the inverse of De Boor algorithm

In this article a simple and effective controller design is introduced for the Hammerstein systems that are identified based on observational input/output data. The nonlinear static function in the Hammerstein system is modelled using a B-spline neural network. The controller is composed by computing the inverse of the B-spline approximated nonlinear static function, and a linear pole assignment controller. The contribution of this article is the inverse of De Boor algorithm that computes the inverse efficiently. Mathematical analysis is provided to prove the convergence of the proposed algorithm. Numerical examples are utilised to demonstrate the efficacy of the proposed approach.

Tin–osmium cluster formation with a monomeric tin(II) alkyl: the formation, crystal structure and reactivity of [Os3(µ-H)SnR(CO)10], a formal stannyne complex of the osmium triangle {R = C(SiMe3)2C5H4N-2}

The monomeric tin(II) species SnR2{R = C(SiMe3)2C5H4N-2} reacts with [Os3(H)2(CO)10] in hexane to give [Os3(µ-H)SnR(CO)10]1 quantitatively; 1 is the first formal stannyne complex of the triosmium nucleus, in which the picoline nitrogen is coordinated to the tin atom, and which is itself also reactive, being a potential precursor to high nuclearity SnOs clusters.