41 research outputs found
Testing the waters: Exploring the teaching of genres in a Cape flats primary school in South Africa
Twenty years after democracy, the legacy of apartheid and hitherto unmet challenges of
resourcing and teacher development are reflected in a severely inequitable and
underperforming education system. This paper focuses on second language writing in the
middle years of schooling when 80% of learners face a double challenge: to move from
‘common sense’ discourses to the more abstract, specialised discourses of school subjects
and, simultaneously, to a new language of learning, in this case English. It describes an
intervention using a systemic functional linguistic (SFL) genre-based pedagogy involving
72 learners and two teachers in a low socio-economic neighbourhood of Cape Town.
Using an SFL analytical framework, we analyse learners’ development in the information
report genre. All learners in the intervention group made substantial gains in control of
staging, lexis, and key linguistic features. We argue that the scaffolding provided by SFL
genre-based pedagogies together with their explicit focus on textual and linguistic
features offer a means of significantly enhancing epistemic access to the specialised
language of school subjects, particularly for additional language learners. Findings have
implications for language-in-education policy, teacher education, curriculum, pedagogy,
and assessment in multilingual classrooms
Identification of Potential Mediators of Retinotopic Mapping: A Comparative Proteomic Analysis of Optic Nerve from WT and <i>Phr1</i> Retinal Knockout Mice
Retinal ganglion cells (RGCs) transmit visual information
topographically
from the eye to the brain, creating a map of visual space in retino-recipient
nuclei (retinotopy). This process is affected by retinal activity
and by activity-independent molecular cues. <i>Phr1</i>,
which encodes a presumed E3 ubiquitin ligase (PHR1), is required presynaptically
for proper placement of RGC axons in the lateral geniculate nucleus
and the superior colliculus, suggesting that increased levels of PHR1
target proteins may be instructive for retinotopic mapping of retinofugal
projections. To identify potential target proteins, we conducted a
proteomic analysis of optic nerve to identify differentially abundant
proteins in the presence or absence of <i>Phr1</i> in RGCs.
1D gel electrophoresis identified a specific band in controls that
was absent in mutants. Targeted proteomic analysis of this band demonstrated
the presence of PHR1. Additionally, we conducted an unbiased proteomic
analysis that identified 30 proteins as being significantly different
between the two genotypes. One of these, heterogeneous nuclear ribonucleoprotein
M (hnRNP-M), regulates antero-posterior patterning in invertebrates
and can function as a cell surface adhesion receptor in vertebrates.
Thus, we have demonstrated that network analysis of quantitative proteomic
data is a useful approach for hypothesis generation and for identifying
biologically relevant targets in genetically altered biological models
Gastric cancer screening in common variable immunodeficiency
Individuals with common variable immunodeficiency (CVID) have an increased risk of gastric cancer, and gastrointestinal lymphoma, yet screening for premalignant gastric lesions is rarely offered routinely to these patients. Proposed screening protocols are not widely accepted and are based on gastric cancer risk factors that are not applicable to all CVID patients. Fifty-two CVID patients were recruited for screening gastroscopy irrespective of symptoms or blood results and were compared to 40 controls presenting for gastroscopy for other clinical indications. Overall, 34% of CVID patients had intestinal metaplasia (IM), atrophic gastritis or moderate to severe non-atrophic gastritis, which can increase the risk of gastric cancer, compared to 7.5% of controls (p < 0.01). Focal nodular lymphoid hyperplasia, a precursor lesion for gastrointestinal lymphoma, was seen in eight CVID patients (16%), one of whom was diagnosed with gastrointestinal lymphoma on the same endoscopy. High-risk gastric pathology was associated with increased time since diagnosis of CVID, smoking, Helicobacter pylori, a low-serum pepsinogen I concentration, and diarrhea, but not pepsinogen I/II ratio, iron studies, vitamin B12 levels or upper gastrointestinal symptoms. There was a lower rate of detection of IM when fewer biopsies were taken, and IM and gastric atrophy were rarely predicted by the endoscopist macroscopically, highlighting the need for standardized biopsy protocols. The prevalence of premalignant gastric lesions in patients with CVID highlights the need for routine gastric screening. We propose a novel gastric screening protocol to detect early premalignant lesions and reduce the risk of gastric cancer and gastric lymphoma in these patients
The E3 ubiquitin ligase Mycbp2 genetically interacts with Robo2 to modulate axon guidance in the mouse olfactory system
The E3 ubiquitin ligase Mycbp2 and it homologues play an important role in axon guidance and synaptogenesis in Drosophila, Caenorhabditis elegans, zebrafish and mouse. Despite this conserved function, the molecular and cellular basis of Mycbp2-dependent axon guidance remains largely unclear. We have examined here the effect of the loss-of-MYCBP2 function on the topography of the olfactory sensory neuron projection from the nasal cavity to the olfactory bulb in mice. A subpopulation of olfactory sensory axons failed to project to the dorsal surface of the olfactory bulb causing abnormal topography in this neural pathway. These defects were similar to the olfactory bulb phenotype in loss-of-ROBO2 function mice. While mice heterozygous for either Mycbp2 or Robo2 were normal, mice double heterozygous for these two genes produced severe defects in the olfactory system. Therefore, Mycbp2 and Robo2 were found to cooperate within a genetic network that has profound effects on axon guidance. The Mycbp2 phenotype could be partly explained by aberrant patterning of olfactory sensory neurons residing in the dorsal compartment of the nasal cavity. Some of these neurons fail to appropriately express Robo2 which is consistent with their aberrant projection to the ventral olfactory bulb. These results provide the first evidence linking an ubiquitin ligase to an axon guidance receptor during pathfinding in the developing mammalian nervous system