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Multiple Families (multiple + family)

Distribution by Scientific Domains
Life Sciences75%

Terms modified by Multiple Families

  • multiple family member
    		•

    Selected Abstracts

    Evolution and phylogenetic relationships of chitin synthases from yeasts and fungi

    FEMS YEAST RESEARCH, Issue 4 2002
    José Ruiz-Herrera
    Abstract Chitin, the structural component that provides rigidity to the cell wall of fungi is the product of chitin synthases (Chs). These enzymes are not restricted to fungi, but are amply distributed in four of the five eukaryotic ,crown kingdoms'. Dendrograms obtained by multiple alignment of Chs revealed that fungal enzymes can be classified into two divisions that branch into at least five classes, independent of fungal divergence. In contrast, oomycetes and animals each possess a single family of Chs. These results suggest that Chs originated as a branch of ,-glycosyl-transferases, once the kingdom Plantae split from the evolutionary line of eukaryotes. The existence of a single class of Chs in animals and Stramenopiles, against the multiple families in fungi, reveals that Chs diversification occurred after fungi departed from these kingdoms, but before separation of fungal groups. Accordingly, each fungal taxon contains members with enzymes belonging to different divisions and classes. Multiple alignment revealed the conservation of specific motifs characteristic of class, division and kingdom, but the strict conservation of only three motifs QXXEY, EDRXL and QXRRW, and seven isolated amino acids in the core region of all Chs. Determination of different structural features in this region of Chs brought to light a noticeable conservation of secondary structure in the proteins. [source]

    Screening of ARHSP-TCC patients expands the spectrum of SPG11 mutations and includes a large scale gene deletion,

    HUMAN MUTATION, Issue 3 2009
    Paola S. Denora
    Abstract Autosomal recessive spastic paraplegia with thinning of corpus callosum (ARHSP-TCC) is a complex form of HSP initially described in Japan but subsequently reported to have a worldwide distribution with a particular high frequency in multiple families from the Mediterranean basin. We recently showed that ARHSP-TCC is commonly associated with mutations in SPG11/KIAA1840 on chromosome 15q. We have now screened a collection of new patients mainly originating from Italy and Brazil, in order to further ascertain the spectrum of mutations in SPG11, enlarge the ethnic origin of SPG11 patients, determine the relative frequency at the level of single Countries (i.e., Italy), and establish whether there is one or more common mutation. In 25 index cases we identified 32 mutations; 22 are novel, including 9 nonsense, 3 small deletions, 4 insertions, 1 in/del, 1 small duplication, 1 missense, 2 splice-site, and for the first time a large genomic rearrangement. This brings the total number of SPG11 mutated patients in the SPATAX collection to 111 cases in 44 families and in 17 isolated cases, from 16 Countries, all assessed using homogeneous clinical criteria. While expanding the spectrum of mutations in SPG11, this larger series also corroborated the notion that even within apparently homogeneous population a molecular diagnosis cannot be achieved without full gene sequencing. © 2008 Wiley-Liss, Inc. [source]

    Do canal-cutting behaviours facilitate host-range expansion by insect herbivores?

    BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009
    DAVID E. DUSSOURD
    According to the escalation,radiation model of co-evolution, insect herbivores that acquire the ability to circumvent a plant defence enter a new adaptive zone and increase in species. How herbivore counter-adaptations to plant defences might lead to speciation is poorly understood. Studies of nymphalid butterflies suggest that the evolution of a broadened host range may be a critical step. This paper examines if leaf-feeding insects capable of deactivating defensive plant canals with canal cutting often have broad host ranges. A total of 94 species of canal-cutting insects were identified from the literature, including eight new canal cutters described in this paper. Only 27% of canal cutters with known host ranges are generalists that feed on plants in multiple families. The proportion of generalist canal cutters is similar or lower than estimates of generalists among phytophagous insects overall. Only five species, at most, of the canal-cutting generalists feed exclusively on plants with secretory canals. The paucity of generalists can be attributed in part to the considerable taxonomic distance separating canal-bearing plant families and to their corresponding chemical distinctiveness. The dependence of many canal-cutting species on host chemicals for defence would also favour specialization. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 715,731. [source]

    Barriers and Enablers to the Use of Measures to Prevent Pediatric Scalding in Cape Town, South Africa

    PUBLIC HEALTH NURSING, Issue 3 2010
    Ashley Van Niekerk
    ABSTRACT Objective: Little attention has been paid to the prevention of pediatric scalding injuries in low-income settings, especially from the standpoint of local stakeholders. This study investigates stakeholder understandings of potential measures to prevent childhood scalding and the related hinders and enablers to such measures. Design and Sample: The study utilized an exploratory qualitative design. Content analysis was applied to the transcriptions of interviews with 13 caregivers and 8 burn prevention research, policy, and practitioner professionals. Measures: The study used semistructured interviews using illustrations to generate data. The 21 individual interviews were audio-recorded, transcribed verbatim, and analyzed using content analytic steps. Interviews focused on 2 illustrations that depict circumstances that surround the occurrence of pediatric scalding typical for Cape Town. Results: 3 categories of prevention measures were identified: enhancements to the safety of the home environment, changes to practice, and improvements to individual competence. The barriers identified were spatial constraints in homes, hazardous home facilities, and multiple family demands. Conclusions: Caregivers and professionals report a similar range of measures to prevent pediatric scalding. Many of these might not be readily implementable in low-income settings with key barriers that would need to be addressed by policymakers and prevention practitioners. [source]