Identification of stimuli that mediate experience-dependent modification of homosexual courtship inDrosophila melanogaster

A naive, sexually matureD. melanogaster male tested with a young, sexually immature male will perform vigorous courtship, but the mature male will perform much less courtship if he is subsequently tested with a second young male. This phenomenon is called experience-dependent courtship modification (EDCM). We have shown that exposure to either or both of the two courtship-stimulating pheromones that immature males synthesize is sufficient to induce EDCM.     

Development and characterisation of neutralising monoclonal antibody to the SARS-coronavirus

There is a global need to elucidate protective antigens expressed by the SARS-coronavirus (SARS-CoV). Monoclonal antibody reagents that recognise specific antigens on SARS-CoV are needed urgently. In this report, the development and immunochemical characterisation of a panel of murine monoclonal antibodies (mAbs) against the SARS-CoV is presented, based upon their specificity, binding requirements, and biological activity. Initial screening by ELISA, using highly purified virus as the coating antigen, resulted in the selection of 103 mAbs to the SARS virus. Subsequent screening steps reduced this panel to seventeen IgG mAbs. A single mAb, F26G15, is specific for the nucleoprotein as seen in Western immunoblot while five other mAbs react with the Spike protein. Two of these Spike-specific mAbs demonstrate the ability to neutralise SARS-CoV in vitro while another four Western immunoblot-negative mAbs also neutralise the virus. The utility of these mAbs for diagnostic development is demonstrated. Antibody from convalescent SARS patients, but not normal human serum, is also shown to specifically compete off binding of mAbs to whole SARS-CoV. These studies highlight the importance of using standardised assays and reagents. These mAbs will be useful for the development of diagnostic tests, studies of SARS-CoV pathogenesis and vaccine development.     

Abnormalities of cholesterol metabolism in autism spectrum disorders.

Although Smith-Lemli-Opitz Syndrome (SLOS), a genetic condition of impaired cholesterol biosynthesis, is associated with autism [Tierney et al., 2001; Am J Med Genet 98:191-200.], the incidence of SLOS and other sterol disorders among individuals with autism spectrum disorders (ASD) is unknown. This study investigated (1) the incidence of biochemically diagnosed SLOS in blood samples from a cohort of subjects with ASD from families in which more than one individual had ASD and (2) the type and incidence of other sterol disorders in the same group. Using gas chromatography/mass spectrometry, cholesterol, and its precursor sterols were quantified in 100 samples from subjects with ASD obtained from the Autism Genetic Resource Exchange (AGRE) specimen repository. Although no sample had sterol levels consistent with SLOS, 19 samples had total cholesterol levels lower than 100 mg/dl, which is below the 5th centile for children over age 2 years. These findings suggest that, in addition to SLOS, there may be other disorders of sterol metabolism or homeostasis associated with ASD.     

Frequent spontaneous deletions at a shuttle vector locus in transgenic mice

Transgenic mice carrying multiple copies of a recoverable lambdaphage shuttle vector (     

Predictors of low CD4 count in resource-limited settings: based on an antiretroviral-naive heterosexual thai population

A barrier to the appropriate provision of antiretroviral therapy to treat immunosuppressed HIV-infected persons in resource-poor countries is identifying who requires treatment. The World Health Organization (WHO) has suggested using a clinical algorithm combined with a total lymphocyte count (TLC) < 1200 cells/mm as a surrogate for a CD4 count less than 200 cells/mm when it is not possible to measure the CD4 count. We evaluated various TLC levels, anemia, and body mass index and compared our data with the WHO criteria to develop a more sensitive algorithm to predict CD4 counts of < 200 cells/mm and < 350 cells/mm in 839 men and women from Thailand infected with HIV-1 subtype E (CRF01_AE). The December 2003 WHO guidelines had a sensitivity of 34.1% in men and 31.8% in women to detect persons with a CD4 count < 200 cells/mm in this HIV-infected population from Thailand. The use of a TLC < 1500 cells/mm or TLC < 2000 cells/mm combined with anemia or WHO stage II infection doubled the sensitivity to detect persons with a CD4 count < 200 (63.0% in men, 68.2% in women) with less than a 6% decrease in specificity.     

From surnames to the history of Y chromosomes: the Sardinian population as a paradigm

A total of 202 Sardinian male subjects were examined for 13 biallelic stable markers, the complex 49a,f/TaqI system and three microsatellites of the Y chromosome in order to investigate, through surname analysis, on a possible territorial heterogeneity inside the island. The study of geographical distribution and linguistic derivation of Sardinian surnames allow us to discover their 'probable place of origin' and reconstruct ancient genetic isolates which borders are, today, no more recognizable. The molecular analysis revealed that about 90% of the Sardinian Y chromosomes fell into haplogroups E-M35, G-M201, I-M26, J-12f2 and R-M269. In contrast with the territorial homogeneity of these haplogroups, when the individuals were distributed according to their birthplace, a significant difference between the three historically and culturally distinct geographical areas into which Sardinia can be subdivided was observed when the individuals were distributed according to the ancestral location of surnames. In particular, the major contribution to this heterogeneity is due to the 'Sardinian-specific' haplogroup I-M26 (almost completely associated with the 49a,f-Ht12/12f2-10Kb/YCAIIa-21/YCAIIb-11 compound haplotype), which shows both a significantly higher incidence in the central-eastern (archaic) area and a significantly lower frequency in the northern area. The results of this study agree with the hypothesis that the ancestral homeland of this specific subset of haplogroup I is the mountainous central-eastern area of Sardinia, where the population underwent a long history of isolation since ancient times, and highlight the informative power of the surname analysis.     

Neurobehavioral phenotype in carriers of the fragile X premutation

There have been contradictory findings in the fragile X (fraX) literature about possible neurocognitive and psychological symptoms due to the fraX premutation (pM). The purpose of the present study was to investigate the relationship between CGG repeat length and neurobehavioral functioning in carriers of the fraX pM. Eighty‐five female carriers of the pM with allele sizes ranging from 59–166 were administered a comprehensive IQ test (WAIS‐III) and completed a questionnaire designed to measure psychopathology (Symptom Checklist (SCL)‐90‐R). No relationship between allele size and cognition was identified. A significant negative relationship between allele size and age was found, as well as a positive relationship between allele size and depression. Follow‐up analyses separating small and large allele sizes (below and above 100 CGG repeats) indicated that individuals with larger allele sizes scored significantly higher on the Interpersonal Sensitivity and Depression subscales of the SCL‐90‐R. Despite the limitation of few individuals with high CGG repeat lengths, our findings suggest that females with larger premutated alleles (≥ 100 repeats) display some clinical manifestations of fraX syndrome. © 2001 Wiley‐Liss, Inc.     

Micronuclei containing whole chromosomes harbouring the selectable gene do not lead to mutagenesis

Loss of heterozygosity is one genetic change observed in manytumours. We do not know whether the loss of chromosomal materialthrough micronucleus formation is a viable mechanism associatedwith, and possibly leading to, genetic disease. Previously,we treated L5178Y mouse lymphoma cells with four aneugens. Althoughthese aneugens induced micronuclei containing predominantlywhole chromosomes, they did not induce mutations at Tk1, theselectable gene, under the same non-toxic conditions in whichthey induced micronuclei. This suggested that the inductionof micronuclei containing whole chromosomes was not an earlyevent leading to phenotypically expressed mutations in thesecells under the conditions used. However, it is possible thatchromosome 11, on which Tk1 resides, may be under-representedin the micronucleus population. To find out the frequency ofinduction of micronuclei containing chromosome 11, we appliedfluorescence in situ hybridization using a chromosome 11 paintto micronuclei induced by colcemid and vinblastine. We foundthat the numbers of micronuclei containing chromosome 11 aremore than sufficient to be detectable as mutations if thesemicronuclei lead to viable mutants. We conclude that the formationof micronuclei containing whole chromosomes does not lead toviable, dividing mutants in this system. ⁵To whom correspondence should be addressed