RAPID TEST FOR DIAGNOSIS OF ENTEROHEMORRHAGIC E. COLI O157:H7 IN HUMAN STOOL SAMPLES

A new rapid test platform for the direct detection of E. coli O157:H7 in stool samples of infected patients was compared with the current standard methods. The new test, DIAPRO FAST-Q®, used biochip ICEflo ®technology that provided results within 20 min. Twenty-one stool samples from patients infected with E. coli O157:H7 or of unknown status were studied. Using the DIAPRO FAST-Q® method, within 20 min, we confirmed positive results for the seven known E. coli O157:H7 samples. While the standard culture method gave rise to only four positives in the remaining 14 unknown samples, the DIAPRO FAST-Q® detected E. coli O157:H7 in eight of these samples, which was confirmed subsequently by broth enrichment culture method.     

The importance of cytoplasmic male killing elements in natural populations of the two spot ladybird, Adalia bipunctata (Linnaeus) (Goleoptera: Goccinellidae)

Adalia bipunctata , the two spot ladybird, is polymorphic for a cytoplasmically inherited element which produces female-biased sex ratios by effecting the death of male offspring during embryogenesis. The levels of this element were assessed in Cambridge populations. Six out of 82 females tested showed both a female-biased sex ratio and low egg hatch rates consistent with the presence of this element. Population sex ratios were assessed by collecting pupae from the Cambridge area. The population sex ratio was found to be 1.15: 1, female biased, significantly different from 1:1, and consistent with predictions based on a model incorporating the observed level of the sex ratio element in the population.     

Developmental Gene Expression in Amphioxus: New Insights into the Evolutionary Origin of Vertebrate Brain Regions, Neural Crest, and Rostrocaudal Segmentation

SYNOPSIS. Amphioxus is widely held to be the closest invertebraterelative of the vertebrates and the best available stand-infor the proximate ancestor of the vertebrates. The spatiotemporalexpression patterns of developmental genes can help suggestbody part homologies between vertebrates and amphioxus. Thisapproach is illustrated using five homeobox genes (AmphiHoxl,AmphiHox2, AmphiOtx, AmphiDll, and AmphiEri) to provide insightsinto the evolutionary origins of three important vertebratefeatures: the major brain regions, the neural crest, and rostrocaudalsegmentation. During amphioxus development, the neural expressionpatterns of these genes are consistent with the presence ofa forebrain (detailed neuroanatomy indicates that the forebrainis all diencephalon without any telencephalon) and an extensivehindbrain; the possible presence of a midbrain requires additionalstudy. Further, during neurulation, the expression pattern ofAmphiDll as well as migratory cell behavior suggest that theepidermal cells bordering the neural plate may represent a phylogeneticprecursor of the vertebrate neural crest. Finally, when theparaxial mesoderm begins to segment, the earliest expressionof AmphiEn is detected in the posterior part of each nascentand newly formed somite. This pattern recalls the expressionof the segment-polarity gene engrailed during establishmentof the segments of metameric protostomes. Thus, during animalevolution, the role of engrailed in establishing and maintainingmetameric body plans may have arisen in a common segmented ancestorof both the protostomes and deuterostomes.     

Selection of Nonmotile Tetrahymena with Ficoll Underlayers*,†

The mechanisms regulating the development of cilia in Tetrahymena are poorly understood but might be revealed through the study of ciliogenesis mutants. Failure to regenerate cilia after dibucaine deciliation results in continued absence of motility. Therefore, to isolate ciliogenesis mutants efficiently, methods for separating motile and nonmotile cells are essential. We examined the efficacy of Ficoll underlayers for these separations. Ciliates of T. thermophila strain mpr^-/mpr (6 mp sens IV) (6-methyl purine-sensitive; mating type IV) were mixed with Ficoll and added as underlayers to separatory funnels containing growth medium. At 27 C most of the cells remained motile and were found in the top layer; at 37 C, there was a time-dependent increase in the number of nonmotile cells and the number of cells in the Ficoll layer. After 150 min at 37 C, most of the cells became nonmotile and were found in the Ficoll layer. Other studies indicated that at 37 C, the cells remained alive and capable of regenerating cilia when deciliated. Thus, it is clear that the Ficoll underlayer effectively separates the majority of nonmotile cells from the majority of motile cells. Evidently, however, at 37 C wild-type T. thermophila exhibit temperature-sensitive phenotypic variability with regard to motility which should be minimized when selecting for mutations affecting motility and ciliogenesis.     

Foodplant effects on colour morphs of Eumorpha fasciata caterpillars (Lepidoptera: Sphingidae)

Caterpillars of the hawkmoth Eumorpha fasciata are highly polymorphic for colour, with green, pink, and pink-and-yellow forms in the second through fourth instars, and green and multicoloured forms in the fifth instar. Four years of field censuses on four foodplant species determined that all morphs were found on all plant species; morph frequencies were homogeneous on each plant species over time; and morph frequencies differed consistently among plant species. When larvae were reared from eggs on three of the hostplant species in the laboratory, differences in morph frequencies paralleled the census results. Thus foodplant quality is one factor affecting larval colour in E. fasciata. A literature survey reveals that foodplant effects on larval colouration may be widespread in the family Sphingidae, but most reports are anecdotal rather than experimental. The implications of this mechanism of colour determination are discussed.     

Building a Research Agenda for Indigenous Epistemologies and Education

One emergent issue in relation to research on Indigenous epistemologies and education concerns the extent to which Indigenous epistemologies lead to new kinds of educational experiences and outcomes and pose new research questions. This commentary responds to the sense of limits and possibilities for Indigenous education that are raised by the research in this theme issue, and suggests that there are indeed new questions to be asked and answered through research.