1,834 research outputs found
The ossified interclinoid ligament
The paper presents an anatomical description of the ossified interclinoid ligament
which was found in a male human skull. In the case studied the ossified
ligament exists as a bony bridge between the anterior and posterior clinoid
processes on the left side of the skull. The length of this connection was measured
as 5.0 mm, while its thickness was 3.2 mm. We conjecture that the presence
of a considerably thick bony trabecula within the sella region might have
had an impact on the course of the internal carotid artery or the oculomotor
nerve, causing compression of these structures
Knockdown of the C. elegans kinome identifies kinases required for normal protein homeostasis, mitochondrial network structure, and sarcomere structure in muscle
Kinases are important signalling molecules for modulating cellular processes and major targets of drug discovery programs. However, functional information for roughly half the human kinome is lacking. We conducted three kinome wide, >90%, RNAi screens and epistasis testing of some identified kinases against known intramuscular signalling systems to increase the functional annotation of the C. elegans kinome and expand our understanding of kinome influence upon muscle protein degradation
Chemically defined medium and Caenorhabditis elegans
BACKGROUND: C. elegans has been established as a powerful genetic system. Use of a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of use in large-scale growth and screening of animals. RESULTS: We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats to using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change the composition of the defined medium. CONCLUSIONS: As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool
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Nonword repetition depends on the frequency of sublexical representations at different grain sizes: evidence from a multi-factorial analysis
The nonword repetition task (NWR) has been widely used in basic cognitive and clinical research, as well as in clinical assessment, and has been proposed as a clinical marker for Specific Language Impairment (SLI). Yet the mechanisms underlying performance on this task are not clear. This study offers insights into these mechanisms through a comprehensive examination of item-related variables identified in previous research as possibly contributing to NWR scores and through testing the predictive power of each in relation to the others. A unique feature of the study is that all factors are considered simultaneously. Fifty-seven typically developing children were tested with a NWR task containing 150 nonwords differing in length, phonotactic probability, lexical neighbourhood and phonological complexity. The results indicate that phonological processing of novel words draws on sublexical representations at all grain sizes and that these representations are phonological, unstructured and insensitive to morphemehood. We propose a novel index – mean ngram frequency of all phonemes – that best captures the extent to which a nonword draws on sublexical representations. The study demonstrates the primacy of sublexical representations in NWR performance with implications for the nature of the deficit in SLI
Bilingualism caught in a net: A new approach to understanding the complexity of bilingual experience
The growing importance of research on bilingualism in psychology and neuroscience motivates the need for a psychometric model that can be used to understand and quantify this phenomenon. This research is the first to meet this need. We reanalyzed two data sets (N = 171 and N = 112) from relatively young adult language-unbalanced bilinguals and asked whether bilingualism is best described by the factor structure or by the network structure. The factor and network models were established on one data set and then validated on the other data set in a fully confirmatory manner. The network model provided the best fit to the data. This implies that bilingualism should be conceptualized as an emergent phenomenon arising from direct and idiosyncratic dependencies among the history of language acquisition, diverse language skills, and language-use practices. These dependencies can be reduced to neither a single universal quotient nor to some more general factors. Additional in-depth network analyses showed that the subjective perception of proficiency along with language entropy and language mixing were the most central indices of bilingualism, thus indicating that these measures can be especially sensitive to variation in the overall bilingual experience. Overall, this work highlights the great potential of psychometric network modeling to gain a more accurate description and understanding of complex (psycho)linguistic and cognitive phenomena
Identification and Functional Clustering of Genes Regulating Muscle Protein Degradation from amongst the Known C. elegans Muscle Mutants
Loss of muscle mass via protein degradation is an important clinical problem but we know little of how muscle protein degradation is regulated genetically. To gain insight our labs developed C. elegans into a model for understanding the regulation of muscle protein degradation. Past studies uncovered novel functional roles for genes affecting muscle and/or involved in signalling in other cells or tissues. Here we examine most of the genes previously identified as the sites of mutations affecting muscle for novel roles in regulating degradation. We evaluate genomic (RNAi knockdown) approaches and combine them with our established genetic (mutant) and pharmacologic (drugs) approaches to examine these 159 genes. We find that RNAi usually recapitulates both organismal and sub-cellular mutant phenotypes but RNAi, unlike mutants, can frequently be used acutely to study gene function solely in differentiated muscle. In the majority of cases where RNAi does not produce organismal level phenotypes, sub-cellular defects can be detected; disrupted proteostasis is most commonly observed. We identify 48 genes in which mutation or RNAi knockdown causes excessive protein degradation; myofibrillar and/or mitochondrial morphologies are also disrupted in 19 of these 48 cases. These 48 genes appear to act via at least three sub-networks to control bulk degradation of protein in muscle cytosol. Attachment to the extracellular matrix regulates degradation via unidentified proteases and affects myofibrillar and mitochondrial morphology. Growth factor imbalance and calcium overload promote lysosome based degradation whereas calcium deficit promotes proteasome based degradation, in both cases myofibrillar and mitochondrial morphologies are largely unaffected. Our results provide a framework for effectively using RNAi to identify and functionally cluster novel regulators of degradation. This clustering allows prioritization of candidate genes/pathways for future mechanistic studies
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