Molecular epidemiology of human rhinovirus infections in Kilifi, coastal Kenya

This study reports pediatric surveillance over 3 years for human rhinovirus (HRV) at the District Hospital of Kilifi, coastal Kenya. Nasopharyngeal samples were collected from children presenting at outpatient clinic with no signs of acute respiratory infection, or with signs of upper respiratory tract infection, and from children admitted to the hospital with lower respiratory tract infection. Samples were screened by real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR) and classified further to species by nucleotide sequencing of the VP4/VP2 junction. Of 441 HRV positives by real-time RT-PCR, 332 were classified to species, with 47% (155) being HRV-A, 5% (18) HRV-B, and 48% (159) HRV-C. There was no clear seasonal pattern of occurrence for any species. The species were present in similar proportions in the inpatient and outpatient sample sets, and no significant association between species distribution and the severity of lower respiratory tract infection in the inpatients could be determined. HRV sequence analysis revealed multiple but separate clusters in circulation particularly for HRV-A and HRV-C. Most HRV-C clusters were distinct from reference sequences downloaded from GenBank. In contrast, most HRV-A and HRV-B sequences clustered with either known serotypes or strains from elsewhere within Africa and other regions of the world. This first molecular epidemiological study of HRV in the region defines species distribution in accord with reports from elsewhere in the world, shows considerable strain diversity and does not identify an association between any species and disease severity

Embryotoxic Effects of Three Natural Occurring \u3cem\u3eVeratrum\u3c/em\u3e Alkaloids and One Synthetic Analog using In Vitro Produced Bovine Embryos

Three natural occurring plant toxins from Veratrum californicum and one related synthetic analog were screened for embryotoxicity using in vitro bovine embryo production techniques. Bovine oocytes were aspirated from ovaries collected from a local abattoir and embryos were generated through in vitro maturation (IVM) and in vitro culture (IVC) procedures. The three natural steroidal alkaloids, cyclopamine, jervine and veratramine and the synthetic steroidal derivative of cyclopamine, cyclopamine-4-en-3-one, were added to IVM and IVC media at 12 μM. Oocytes were exposed to the toxins during maturation (IVM) and pre-implantation embryo during culture (IVC). Cleavage rates and embryo growth (morula and blastocyst production) and development through the hatched blastocyst stage were evaluated. Cyclopamine and cyclopamine-4-en-3-one inhibited cleavage rates and embryo growth and development of morulae and blastocysts in culture. Oocytes that were exposed to cyclopamine and cyclopamine-4-en-3-one during IVM only showed reduced cleavage rates and resulted in lower numbers of embryos that developed to the morula, blastocyst, and hatched blastocyst stages. The effects of these steroidal alkaloids on the oocyte during IVM and on the embryo during all stages of development up to and including the hatched blastocyst stage, demonstrates a dramatic cytotoxic effect on oocytes maturation and early pre-implantation embryos. This research also suggests that the Hedgehog signaling pathway may play a role in the maturing oocyte as well as the pre-implantation embryo. These in vitro fertilization techniques provide an economical, rapid through put and effective method to screen natural toxins, especially suspected reproductive toxins for cytotoxicity

Comparison of Sheep and Goats to the Acute Toxic Effects of Foothill Death Camas

Death camas (Zigadenus spp) is a perennial forb found throughout the western United States, which is known to kill both sheep and cattle. In a previous study, goats appeared to be somewhat resistant to the adverse effects of death camas. Therefore, the objective of this study was to directly compare the susceptibility of goats and sheep to the acute toxic effects of death camas. Sheep and goats were dosed at 0.5, 1.0, 2.0, 4.0, and 6.0 g death camas per kg BW. The data presented in this manuscript suggest that goats are more susceptible to death camas than sheep. There were no differences in the serum concentrations of zygadenine in sheep versus goats. There was a difference between goats and sheep in the severity of observed clinical signs of poisoning. This is highlighted by the fact that five goats from the two highest doses died, whereas none of the sheep died. Consequently, when grazing goats in death camas infested pastures as much caution, if not more, should be taken than one would with sheep. Additionally, the data presented in the study suggests that goats can be used as a small ruminant model to study the toxic effects of death camas

Synthesis and biological evaluation of 1,2-disubsubstituted 4-quinolone analogues of Pseudonocardia sp. natural products.

A series of analogues of Pseudonocardia sp. natural products were synthesized, which have been reported to possess potent antibacterial activity against Helicobacter pylori and induce growth defects in Escherichia coli and Staphylococcus aureus. Taking inspiration from a methodology used in our total synthesis of natural products, we applied this methodology to access analogues possessing bulky N-substituents, traditionally considered to be challenging scaffolds. Screening of the library provided valuable insights into the structure-activity relationship of the bacterial growth defects, and suggested that selectivity between bacterial species should be attainable. Furthermore, a structurally related series of analogues was observed to inhibit production of the virulence factor pyocyanin in the human pathogen Pseudomonas aeruginosa, which may be a result of their similarity to the Pseudomonas quinolone signal (PQS) quorum sensing autoinducer. This provided new insights regarding the effect of N-substitution in PQS analogues, which has been hitherto underexplored.SF was supported by a BBSRC studentship. DRS acknowledges support from the Engineering and Physical Sciences Research Council (EP/P020291/1) and Royal Society (Wolfson Research Merit Award)

The word landscape of the non-coding segments of the Arabidopsis thaliana genome

<p>Abstract</p> <p>Background</p> <p>Genome sequences can be conceptualized as arrangements of motifs or words. The frequencies and positional distributions of these words within particular non-coding genomic segments provide important insights into how the words function in processes such as mRNA stability and regulation of gene expression.</p> <p>Results</p> <p>Using an enumerative word discovery approach, we investigated the frequencies and positional distributions of all 65,536 different 8-letter words in the genome of <it>Arabidopsis thaliana</it>. Focusing on promoter regions, introns, and 3' and 5' untranslated regions (3'UTRs and 5'UTRs), we compared word frequencies in these segments to genome-wide frequencies. The statistically interesting words in each segment were clustered with similar words to generate motif logos. We investigated whether words were clustered at particular locations or were distributed randomly within each genomic segment, and we classified the words using gene expression information from public repositories. Finally, we investigated whether particular sets of words appeared together more frequently than others.</p> <p>Conclusion</p> <p>Our studies provide a detailed view of the word composition of several segments of the non-coding portion of the <it>Arabidopsis </it>genome. Each segment contains a unique word-based signature. The respective signatures consist of the sets of enriched words, 'unwords', and word pairs within a segment, as well as the preferential locations and functional classifications for the signature words. Additionally, the positional distributions of enriched words within the segments highlight possible functional elements, and the co-associations of words in promoter regions likely represent the formation of higher order regulatory modules. This work is an important step toward fully cataloguing the functional elements of the <it>Arabidopsis </it>genome.</p

Deletion of genes encoding PU.1 and Spi-B in B cells impairs differentiation and induces pre-B cell acute lymphoblastic leukemia

The E26 transformation-specific (Ets) transcription factor PU.1 is required to generate lymphoid progenitor cells from hematopoietic stem cells, but it is not required to generate B cells from committed B-cell lineage progenitors.We hypothesized that PU.1 function in B-cell differentiation is complemented by the related Ets transcription factor Spi-B. To test this hypothesis, mice were generated lacking both PU.1 and Spi-B in the B-cell lineage. Unlike mice lacking PU.1 or Spi-B, mice deficient in both PU.1 and Spi-B in the B-cell lineage had reduced frequencies of B cells as well as impaired B-cell differentiation. Strikingly, all PU.1 and Spi-B-deficient mice developed pre-B cell acute lymphoblastic leukemia before 30 weeks of age. Pre-B cells accumulated in the thymus resulting in massive thymic enlargement and dyspnea. These findings demonstrate that PU.1 and Spi-B are essential transcriptional regulators of B-cell differentiation as well as novel tumor suppressors in the B-cell lineage. © 2011 by The American Society of Hematology

Influenza surveillance among children with pneumonia admitted to a district hospital in coastal Kenya, 2007-2010

Background: Influenza data gaps in sub-Saharan Africa include incidence, case fatality, seasonal patterns, and associations with prevalent disorders. Methods: Nasopharyngeal samples from children aged <12 years who were admitted to Kilifi District Hospital during 2007–2010 with severe or very severe pneumonia and resided in the local demographic surveillance system were screened for influenza A, B, and C viruses by molecular methods. Outpatient children provided comparative data. Results: Of 2002 admissions, influenza A virus infection was diagnosed in 3.5% (71), influenza B virus infection, in 0.9% (19); and influenza C virus infection, in 0.8% (11 of 1404 tested). Four patients with influenza died. Among outpatients, 13 of 331 (3.9%) with acute respiratory infection and 1 of 196 without acute respiratory infection were influenza positive. The annual incidence of severe or very severe pneumonia, of influenza (any type), and of influenza A, was 1321, 60, and 43 cases per 100 000 <5 years of age, respectively. Peak occurrence was in quarters 3–4 each year, and approximately 50% of cases involved infants: temporal association with bacteremia was absent. Hypoxia was more frequent among pneumonia cases involving influenza (odds ratio, 1.78; 95% confidence interval, 1.04–1.96). Influenza A virus subtypes were seasonal H3N2 (57%), seasonal H1N1 (12%), and 2009 pandemic H1N1 (7%). Conclusions: The burden of influenza was small during 2007–2010 in this pediatric hospital in Kenya. Influenza A virus subtype H3N2 predominated, and 2009 pandemic influenza A virus subtype H1N1 had little impact