Mutation in the Gene Encoding Ubiquitin Ligase LRSAM1 in Patients with Charcot-Marie-Tooth Disease

Charcot-Marie-Tooth disease (CMT) represents a family of related sensorimotor neuropathies. We studied a large family from a rural eastern Canadian community, with multiple individuals suffering from a condition clinically most similar to autosomal recessive axonal CMT, or AR-CMT2. Homozygosity mapping with high-density SNP genotyping of six affected individuals from the family excluded 23 known genes for various subtypes of CMT and instead identified a single homozygous region on chromosome 9, at 122,423,730–129,841,977 Mbp, shared identical by state in all six affected individuals. A homozygous pathogenic variant was identified in the gene encoding leucine rich repeat and sterile alpha motif 1 (LRSAM1) by direct DNA sequencing of genes within the region in affected DNA samples. The single nucleotide change mutates an intronic consensus acceptor splicing site from AG to AA. Direct analysis of RNA from patient blood demonstrated aberrant splicing of the affected exon, causing an obligatory frameshift and premature truncation of the protein. Western blotting of immortalized cells from a homozygous patient showed complete absence of detectable protein, consistent with the splice site defect. LRSAM1 plays a role in membrane vesicle fusion during viral maturation and for proper adhesion of neuronal cells in culture. Other ubiquitin ligases play documented roles in neurodegenerative diseases. LRSAM1 is a strong candidate for the causal gene for the genetic disorder in our kindred.     

Tissue‐dependent induction of apoptosis by matrix metalloproteinase stromelysin‐3 during amphibian metamorphosis

Matrix metalloproteinases (MMPs) are a superfamily of Zn²⁺‐dependent proteases that are capable of cleaving the proteinaceous component of the extracellular matrix (ECM). The ECM is a critical medium for cell–cell interactions and can also directly signal cells through cell surface ECM receptors, such as integrins. In addition, many growth factors and signaling molecules are stored in the ECM. Thus, ECM remodeling and/or degradation by MMPs are expected to affect cell fate and behavior during many developmental and pathological processes. Numerous studies have shown that the expression of MMP mRNAs and proteins associates tightly with diverse developmental and pathological processes, such as tumor metastasis and mammary gland involution. In vivo evidence to support the roles of MMPs in these processes has been much harder to get. Here, we will review some of our studies on MMP11, or stromelysin‐3, during the thyroid hormone‐dependent amphibian metamorphosis, a process that resembles the so‐called postembryonic development in mammals (from a few months before to several months after birth in humans when organ growth and maturation take place). Our investigations demonstrate that stromelysin‐3 controls apoptosis in different tissues via at least two distinct mechanisms. Birth Defects Research (Part C) 90:55–66, 2010. © 2010 Wiley‐Liss, Inc.     

Insecticidal activity of Origanum majorana L. essential oil as anti‐cholinergic agent

The present study was focused on exploring the presence of active compounds in Origanum majorana essential oil (OmEO), and its various knock‐down effects against the rice moth, Corcyra cephalonica. GC–MS analysis detected the existence of major compounds such as monoterpenes, cis‐β‐terpineol and terpinen‐4‐ol with the total proportion of 52.16%. Fumigant toxicity against adult and larvae was calculated with an LC₅₀ value of 11.31 and 49.83 μL/L air, respectively. The contact toxicity against adult, pupa, larvae and eggs was observed with LC₅₀ value 2.54, 0.95, 2.78, and 0.49 μL/L, respectively. Furthermore, the influential repellent behavior against adults has been observed. Acetylesterase (AChE) inhibition activity of OmEO was observed against adult and larvae of C. cephalonica with an IC₅₀ value of 35.89 and 118.54 μL/mL, respectively. Moreover, computational docking study revealed the binding affinity of Cis‐β‐terpineol and terpinen‐4‐ol towards the active binding sites of AChE. On the other hand, Fluorescence‐assisted cytometry and comet assay confirmed the cytotoxic and genotoxic effect of OmEO at various concentrations on C. cephalonica. Altogether, the results showed the knock‐down effect of OmEO against C. cephalonica, and it could be a potential biocontrol measure against the stored product pest.     

The evolution of an ideal stent design and its impact on the aortic endothelium during and after percutaneous replacement

Vascular support structures are important devices for treating valve stenosis. A large population of patients is treated for valvular disease and the preferred mode of treatment is percutaneous valve replacement. Stent devices are proving to be an improved technology in minimally invasive cardiac surgery. This new technology provides highly effective results at minimal cost and with a short duration of hospitalisation. Stents as a supporting structure for tissue valves have evolved over the years into remarkably useful and effective devices. During this process, a number of specific designs have come and gone, and a few have remained. Many design changes were successful, and many were not. This article describes the merits and demerits of various stent designs and details the specific reasons why a particular novel design is expected to be the most suitable implant during and after percutaneous aortic valve replacement.     

<Emphasis Type="Italic">Vive la différence</Emphasis>: naming structural variants in the human reference genome

The HUGO Gene Nomenclature Committee has approved gene symbols for the majority of protein-coding genes on the human reference genome. To adequately represent regions of complex structural variation, the Genome Reference Consortium now includes alternative representations of some of these regions as part of the reference genome. Here, we describe examples of how we name novel genes in these regions and how this nomenclature is displayed on our website, http://genenames.org.     

Unique morphogenesis in Saccharomyces cerevisiae strain GS1731

During the lag and early exponential phase of growth, 50–60% of budded cells of Saccharomyces cerevisiae strain GS1731 were multiply budded. During subsequent culture growth, the frequency of multiply budded cells decreased until by stationary phase multiply budded cells were rare. Data from renewed growth of a culture after hydroxyurea treatment indicated that GS1731 mother cells could assemble up to three pre-bud sites and begin bud growth and development in each. Light and scanning electron microscopy showed two or three very small buds emerging simultaneously on a mother cell and either reaching full size at the same time or enlarging sequentially. Immunofluorescence studies revealed that these multiply budded cells had multiple bundles of cytoplasmic microtubules. DAPI staining of nuclei revealed that some of the unbudded mother cells were multinucleate and completed cytokinesis giving rise to normal daughter cells.