Characterization of a truncated soluble form of the baculovirus (AcMNPV) major envelope protein Gp64

A truncated tagged form of the Autographica californica multiple nuclear polyhedrosis virus major surface glycoprotein, gp64, has been expressed using the baculovirus expression system and purified to homogeneity by immune-affinity chromatography. The protein, which is responsible for virus-cell fusion, was a trimer in solution and retained this oligomeric form at pH 5, the pH of fusion. Circular dichroism spectroscopy indicated a protein with mixed alpha-helix and beta-sheet content that did not undergo significant change at pH 5. The soluble protein showed no detectable binding to the insect cell surface. These data suggest a novel fusion mechanism for gp64 compared to models such as the influenza HA. In a crystal screen, deglycosylated, but not glycosylated, preparations of the protein were found to form small needle-shaped crystals that may form the basis of a dedicated structural study.     

A Plasmodium falciparum copper-binding membrane protein with copper transport motifs

Formerly known as a hypoendemic malaria country, the Republic of Djibouti declared the goal of pre-eliminating malaria in 2006. The aim of the present study was to evaluate the prevalence of Plasmodium falciparum, Plasmodium vivax and mixed infections in the Djiboutian population by using serological tools and to identify potential determinants of the disease and hotspots of malaria transmission within the country. The prevalence of P. falciparum and P. vivax within the districts of the capital city and the rest of the Republic of Djibouti were assessed using 13 and 2 serological markers, respectively. The relationship between the immune humeral response to P. falciparum and P. vivax and variables such as age, gender, wealth status, urbanism, educational level, distance to rivers/lakes, living area, having fever in the last month, and staying in a malaria-endemic country more than one year was estimated and analysed by questionnaires administered to 1910 Djiboutians. Multivariate ordinal logistic regression models of the immune humeral response were obtained for P. falciparum and P. vivax. The P. falciparum and P. vivax seroprevalence rates were 31.5%, CI95% [29.4-33.7] and 17.5%, CI95% [15.8-19.3], respectively. Protective effects against P. falciparum and P. vivax were female gender, educational level, and never having visited a malaria-endemic area for more than one year. For P. falciparum only, a protective effect was observed for not having a fever in the last month, living more than 1.5 km away from lakes and rivers, and younger ages. This is the first study that assessed the seroprevalence of P. vivax in the Republic of Djibouti. It is necessary to improve knowledge of this pathogen in order to create an effective elimination programme. As supported by recent observations on the subject, the Republic of Djibouti has probably demonstrated a real decrease in the transmission of P. falciparum in the past seven years, which should encourage authorities to improve efforts toward elimination.     

Mechanoreceptors innervating soft cuticle in the abdomen of the hermit crab, <Emphasis Type="Italic">Pagurus pollicarus</Emphasis>

Mechanoreceptors in the soft cuticle of the 4th abdominal segment of the hermit crab, Pagurus pollicarus, that are associated with reflex activation of abdominal postural motoneuron, were studied to determine whether their properties are consistent with a feedback control of abdominal stiffness. Three classes of receptors were identified: (1) setal dome receptors, (2) hypodermal receptors, and (3) funnel-canal receptors. The hypodermal receptors, which have the largest extracellular action potentials, were selected for further study. Their axons innervate the entire ipsilateral half of a segment; receptive fields of receptors with different amplitudes show extensive overlap. They are phasic and show significant adaptation; at higher frequencies they signal displacement rather than velocity. Although they are activated by changing muscle tension, their threshold for cuticular displacement is much lower than for forces generated by postural muscles. These features suggest that they are primarily involved in signaling cuticular displacement and shearing forces as they contact the columella of the shell in which the hermit crab lives.     

Peripheral and central asymmetry in the swimmeret system of the hermit crab,Pagurus pollicarus

Summary The consequences of the degeneration of all pleopods on the right side in the adult hermit crab were examined by comparing the motor and sensory components of the first root on both sides of the abdomen. In the third segment, the populations of sensory receptors remain relatively unaffected, with the number of units recorded extracellularly, their position and mode of activation, and their conduction velocities similar on the two sides. In contrast, only 2 or 3 somata in the ganglion are back-filled with cobalt via the right first root, compared to approximately 20 filled through the left root. While no remnant of the pleopod musculature remains on the right side, extracellular action potentials propagating centrifugally could be elicited in the right first root. The central cytoarchitecture of the first root neurons, as revealed by cobalt staining, was also studied in 3 other macruran species. The apparent phylogenetic variability revealed in comparing the swimmeret systems of the 4 related decapods is discussed in terms of different probabilistic strategies for crustacean neuromuscular ontogeny.     

How the internet affects patients' experience of cancer: a qualitative study

Objective To explore how men and women with cancer talk about using the internet.Design Qualitative study using semistructured interviews collected by maximum variation sampling.Setting Respondents recruited throughout the United Kingdom during 2001-2.Participants 175 men and women aged 19-83 years, with one of five cancers (prostate, testicular, breast, cervical, or bowel) diagnosed since 1992 and selected to include different stages of treatment and follow up.Results Internet use, either directly or via friend or family, was widespread and reported by patients at all stages of cancer care, from early investigations to follow up after treatment. Patients used the internet to find second opinions, seek support and experiential information from other patients, interpret symptoms, seek information about tests and treatments, help interpret consultations, identify questions for doctors, make anonymous private inquiries, and raise awareness of the cancer. Patients also used it to check their doctors'' advice covertly and to develop an expertise in their cancer. This expertise, reflecting familiarity with computer technology and medical terms, enabled patients to present a new type of “social fitness.”Conclusion Cancer patients used the internet for a wide range of information and support needs, many of which are unlikely to be met through conventional health care. Serious illness often undermines people''s self image as a competent member of society. Cancer patients may use the internet to acquire expertise to display competence in the face of serious illness.     

Fungal virulence studies come of age

Sophisticated molecular biological research has revealed many virulence attributes in at least four pathogenic fungi, but the future study of fungal virulence requires investigators to distinguish between molecules that directly interact with the host, molecules that regulate these, and molecules that are always required for fungal growth and survival, independent of the host.