Outbreak of giardiasis in a daycare nursery.

Seven children and one member of staff in a nursery in Kent became ill with Giardia lamblia infection in three months in a nursery in Kent and three further children were found to carry giardia. Person to person spread among young children who were not toilet trained appeared to be responsible. All staff and children were screened for infection, and the outbreak was controlled by reinforcing hygiene measures, and treating microbiologically confirmed cases and carriers with metronidazole.

FIN219, an auxin-regulated gene, defines a link between phytochrome A and the downstream regulator COP1 in light control of Arabidopsis development.

Light signals perceived by photoreceptors are transduced to negatively regulate COP1, a key repressor of photomorphogenic development. To identify genes involved in light inactivation of COP1, a genetic screen was employed to identify extragenic modifier mutations of a temperature-sensitive cop1 allele. One suppressor mutation isolated also exhibited a far-red-specific long hypocotyl phenotype in a wild-type background. Further phenotypic analyses of this new mutation, named fin219, suggested that it defines a novel phytochrome A signaling component. Genetic analysis indicated that FIN219 interacts closely with another phytochrome A signaling component, FHY1. Molecular characterization of FIN219 indicated that it encodes a cytoplasmic localized protein highly similar to the GH3 family of proteins and its expression is rapidly induced by auxin. In contrast to its loss-of-function mutant phenotype, overexpression of FIN219 results in a far-red-specific hyperphotomorphogenic response. Our data suggest that FIN219 may define a critical link for phytochrome A-mediated far-red inactivation of COP1 and a possible cross-talk juncture between auxin regulation and phytochrome signaling.

Outbreak of hepatitis A in a special needs school in Kent: 1999.

In an outbreak of hepatitis A virus (HAV) infection in a special needs school salivary testing was used to identify those recently infected and those who were immune. The value of such testing as an epidemiological and outbreak control tool is discussed. HAV vaccine rather than human normal immunoglobulin was used to bring the outbreak under control.

The role of COP1 in repression of Arabidopsis photomorphogenic development.

Photomorphogenic development in Arabidopsis is regulated by the key repressor COP1, which interacts with specific transcription factors in the nucleus to modulate their activities. In the dark, COP1 accumulates in the nucleus and represses photomorphogenic development. Light diminishes the nuclear accumulation of COP1 and abrogates its repressor activity. A number of cellular components are involved in light-dependent nucleocytoplasmic partitioning of COP1, including the multisubunit COP9 complexes and at least three well-characterized photoreceptors. This review discusses current understanding of the mechanisms of COP1 action.

An outbreak of viral gastroenteritis associated with eating raw oysters.

Nine members of a party of 24 people who attended a birthday party fell ill with gastroenteritis between one and three days later. A cohort study undertaken using a postal questionnaire showed that illness was associated with having eaten raw oysters. Six of the cases had their stools examined and two were positive for small round structured virus. The illness was brief and none of the cases had consulted a general practitioner. Had the cases not been part of a party they would not have been identified. The oysters were grown in English coastal waters in grade B oyster beds. They underwent depuration treatment before they were sold for consumption. More work is needed to protect oyster beds from contamination and to identify methods to render oysters safe for consumption.

Role of a COP1 interactive protein in mediating light-regulated gene expression in arabidopsis.

Arabidopsis seedlings display distinct patterns of gene expression and morphogenesis according to the ambient light condition. An Arabidopsis nuclear protein, CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), acts to repress photomorphogenesis in the absence of light. The Arabidopsis CIP7 protein was identified by its capability to interact with COP1. CIP7 is a novel nuclear protein that contains transcriptional activation activity without a recognizable DNA binding motif. CIP7 requires light for its high level of expression, and COP1 seems to play a role in repressing its expression in darkness. Decreasing CIP7 expression by introducing antisense CIP7 RNA resulted in defects in light-dependent anthocyanin and chlorophyll accumulation. Antisense plants also displayed reduced expression of light-inducible genes for anthocyanin biosynthesis and photosynthesis. However, no defect was observed in light-dependent inhibition of hypocotyl elongation. Taken together, our data indicate that CIP7 acts as a positive regulator of light-regulated genes and is a potential direct downstream target of COP1 for mediating light control of gene expression.

Molecular interaction between COP1 and HY5 defines a regulatory switch for light control of Arabidopsis development.

Arabidopsis COP1 acts as a light-inactivable repressor of photomorphogenic development, but its molecular mode of action remains unclear. Here, we show that COP1 negatively regulates HY5, a bZIP protein and a positive regulator of photomorphogenic development. Both in vitro and in vivo assays indicate that COP1 interacts directly and specifically with HY5. The hyperphotomorphogenic phenotype caused by the over-expression of a mutant HY5, which lacks the COP1-interactive domain, supports the regulatory role of HY5-COP1 interaction. Further, HY5 is capable of directly interacting with the CHS1 minimal promoter and is essential for its light activation. We propose that the direct interaction with and regulation of transcription factors by COP1 may represent the molecular mechanism for its control of gene expression and photomorphogenic development.

Arabidopsis bZIP protein HY5 directly interacts with light-responsive promoters in mediating light control of gene expression.

The Arabidopsis HY5 gene has been defined genetically as a positive regulator of photomorphogenesis and recently has been shown to encode a basic leucine zipper type of transcription factor. Here, we report that HY5 is constitutively nuclear localized and is involved in light regulation of transcriptional activity of the promoters containing the G-box, a well-characterized light-responsive element (LRE). In vitro DNA binding studies suggested that HY5 can bind specifically to the G-box DNA sequences but not to any of the other LREs present in the light-responsive promoters examined. High-irradiance light activation of two synthetic promoters containing either the consensus G-box alone or the G-box combined with the GATA motif (another LRE) and the native Arabidopsis ribulose bisphosphate carboxylase small subunit gene RBCS-1A promoter, which has an essential copy of the G-box, was significantly compromised in the hy5 mutant. The hy5 mutation's effect on the high-irradiance light activation of gene expression was observed in both photosynthetic and nonphotosynthetic tissues. Furthermore, the characteristic phytochrome-mediated red light- and far-red light-reversible low-fluence induction of the G-box-containing promoters was diminished specifically in hy5 plants. These results suggest that HY5 may interact directly with the G-box in the promoters of light-inducible genes to mediate light-controlled transcriptional activity.

Regulatory hierarchy of photomorphogenic loci: allele-specific and light-dependent interaction between the HY5 and COP1 loci.

Previous studies suggested that the CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) gene product represses photomorphogenic development in darkness and that light signals reverse this action. In this report, we used genetic analysis to investigate the regulatory hierarchical relationship of COP1 and the loci encoding the photoreceptors and other signaling components. Our results showed that cop1 mutations are epistatic to the long hypocotyl mutations hy1, hy2, hy3, and hy4, suggesting that COP1 acts downstream of the phytochromes and a blue light receptor. Although epistasis of a putative null cop1-5 mutation over a hy5 mutation implied that COP1 acts downstream of HY5, the same hy5 mutation can suppress the dark photomorphogenic phenotypes (including hypocotyl elongation and cotyledon cellular differentiation) of the weak cop1-6 mutation. This, and other allele-specific interactions between COP1 and HY5, may suggest direct physical contact of their gene products. In addition, the synthetic lethality of the weak deetiolated1 (det1) and cop1 mutations and the fact that the cop1-6 mutation is epistatic to the det1-1 mutation with respect to light control of seed germination and dark-adaptative gene expression suggested that DET1 and COP1 may act in the same pathway, with COP1 being downstream. These results, together with previous epistasis studies, support models in which light signals, once perceived by different photoreceptors, converge downstream and act through a common cascade(s) of regulatory steps, as defined by DET1, HY5, COP1, and likely others, to derepress photomorphogenic development.

Assembly of flagellar radial spoke proteins in Chlamydomonas: identification of the axoneme binding domain of radial spoke protein 3.

Radial spokes of the eukaryotic flagellum extend from the A tubule of each outer doublet microtubule toward the central pair microtubules. In the paralyzed flagella mutant of Chlamydomonas pf14, a mutation in the gene for one of 17 polypeptides that comprise the radial spokes results in flagella that lack all 17 spoke components. The defective gene product, radial spoke protein 3 (RSP3), is, therefore, pivotal to the assembly of the entire spoke and may attach the spoke to the axoneme. We have synthesized RSP3 in vitro and assayed its binding to axonemes from pf14 cells to determine if RSP3 can attach to spokeless axonemes. In vitro, RSP3 binds to pf14 axonemes, but not to wild-type axonemes or microtubules polymerized from purified chick brain tubulin. The sole axoneme binding domain of RSP3 is located within amino acids 1-85 of the 516 amino acid protein; deletion of these amino acids abolishes binding by RSP3. Fusion of amino acids 1-85 or 42-85 to an unrelated protein confers complete or partial binding activity, respectively, to the fusion protein. Transformation of pf14 cells with mutagenized RSP3 genes indicates that amino acids 18-87 of RSP3 are important to its function, but that the carboxy-terminal 140 amino acids can be deleted with little effect on radial spoke assembly or flagellar motility.

Gene transfer by microinjection in the zebra fish Brachydanio rerio.

Although transgenesis studies of fish started relatively later compared to those of mammals, they have not been completely neglected, and in recent years, many publications have appeared in this field. Reviews of transgenesis in fish are given by Maclean et al., Hew, Maclean and Penman, and Ozato et al. Much attention had been focused on commercially important food species, especially in the attempt to insert beneficial genes, such as the antifreeze and growth-hormone genes, into salmonids, such as trout and salmon. Zhang et al have successfully shown transfer, expression, and inheritance of rainbow trout growth-hormone cDNA microinjected into the common carp.