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.     

Studies of the cellular and free lipopolysaccharides form Neisseria canis and N. subflava.

Cellular and free lipopolysaccharides (LPS) obtained from Neisseria canis and N. subflava were essentially identical. Both cellular and free lipopolysaccharides contained O-polysaccharides of the following composition: L-rhamnose (46 mol), D-glucose (16 mol), L-glycero-D-manno-heptose (2 mol), ethanolamine (2 mol), 3-deoxy-D-manno-octulosonic acid (1 mol), and phosphate (1.5 mol). The core oligosaccharide, which was common to the cellular and free LPS of both organisms, contained L-rhamnose (4 mol), D-glucose (2 mol), L-glycero-D-manno-heptose (2 mol), 3-deoxy-D-manno-octulosonic acid (1 mol), ethanolamine (2 mol), and phosphate (1.5 mol). Accumulated results on LPS composition and structure indicated that Neisseria perflava, N. subflava, and N. flava could not be combined into a single species. On the basis of its nutritional requirements and LPS structure, N. canis could be considered a strain of N. subflava.     

A Cinderella effect in the childcare assistance provided by European grandparents

Survey data from 36,771 European grandparents were analyzed with respect to childcare assistance that interviewees provided to their birth children versus stepchildren. Interviewees with current partners provided far more such assistance to adult children who were the progeny of both partners than to those who were stepchildren of either one's self or one's partner, but both husband and wife helped the wife's children from prior unions more than they helped the husband's children, supporting the interpretation of stepfathers' involvement as primarily an investment in the new partnership (“mating effort”) rather than in the grandchildren. Interviewees resided farther away from their adult stepchildren than from their birth children, on average, but discriminative care did not depend merely on residential proximity, being substantial regardless of whether proximity was statistically controlled. Grandmothers without current partners exhibited the greatest discrimination, with stepchild: birth child Odds Ratios of 0.10 or less in various analyses, whereas grandfathers without partners exhibited no significant discrimination. Interviewees of both sexes listed far more stepchildren, proportionately, if they had a current partner than if they were either widowed or divorced, however, which suggests that single respondents may have omitted former stepchildren with whom they had ceased to interact from their list of children, and hence that the degree to which single grandparents divest from them may be even larger than estimated.     

Comparison of Water,Oils and Emulsifiable Adjuvant Oils as Formulating Agents for <Emphasis Type="Italic">Metarhizium Anisopliae</Emphasis> for Use in Control of <Emphasis Type="Italic">Boophilus Microplus</Emphasis>

Studies were conducted to identify oil-based formulating agents (paraffinic oil, palm oil and emulsifiable adjuvant oils (EAOs)) for Metarhizium anisopliae that were superior to water with simple surfactants using a germination test and a bioassay against Boophilus microplus. Germination of conidia in all formulations, except 10% coconut EAO, produced more than 68% germination at 24 h and nearly 100% at 48 h. Coconut oil (average survival time (AST)=4.6±0.28 days) and 10% liquid paraffin EAO (AST=4.4±0.15 days) enhanced the pathogenicity of M. anisopliae to B. microplus relative to water (AST=8.4±0.42 days). M. anisopliae in 10% liquid paraffin EAO was the most effective formulation having a moderately high germination after 24 h and a low AST as well as a high AST in the control. In the second experiment, germination of conidia in 2% liquid paraffin EAO and 2% Cropspray was higher than in 2% Codacide oil at 24 h, however, all treatments reached 100% germination after 48 h. The ASTs of the EAO based M. anisopliae formulations (Average AST=6.4±0.54 days) were similar but lower that the ASTs of the controls (Average AST=9.6±0.28 days).     

The effects of arginine vasotocin and catecholamines on nitrogen excretion and the cardio-respiratory physiology of the gulf toadfish, Opsanus beta

Simultaneous measurements of cardio-respiratory variables, oxygen uptake and whole body urea/ammonia/tritiated water effluxes were performed on cannulated gulf toadfish, Opsanus beta, before and after intra-arterial injection of the vasoactive agents, adrenaline, isoproterenol and arginine vasotocin. These experiments were conducted to test the hypothesis that the phenomenon of pulsatile urea excretion might reflect sudden changes in the general diffusive properties of the gill for solute transfer. Injection of isoproterenol (final nominal circulating level = 10⁻⁶ mol l⁻¹), was used as a tool to maximise the diffusive and perfusive conditions for branchial solute transfer. This protocol caused a pronounced reduction in arterial blood pressure, an elevation of cardiac frequency and associated increases in whole body urea and tritiated water effluxes; ammonia excretion and oxygen uptake were unaffected. Injection of adrenaline (final nominal circulating level=10⁻⁶ mol l⁻¹), caused a significant increase in arterial blood pressure and a tachycardia, yet nitrogen excretion and oxygen uptake were unaffected. Injection of arginine vasotocin, caused a dose-dependent (final nominal circulating levels = 10⁻¹¹–10⁻⁹ mol l⁻¹) increase in arterial blood pressure without affecting cardiac or ventilation frequency. At the two higher concentrations, arginine vasotocin caused large and transient increases in urea excretion without significantly affecting ammonia, water or oxygen fluxes. These results suggest that increased gill diffusive or perfusive conductance, while capable of augmenting urea efflux, cannot fully explain the sudden and massive increases in urea transfer associated with pulsatile urea excretion in toadfish. It is suggested that pulsatile urea excretion in this species may reflect a specific enhancement of urea excretion under the control of the neurohypophyseal hormone, arginine vasotocin. Accepted: 21 April 1998     

Cold tolerance of hatched and unhatched second stage juveniles of the potato cyst-nematode Globodera rostochiensis

Perry R. N. and Wharton D. A. 1985. Cold tolerance of hatched and unhatched second stage juveniles of the potato cyst-nematode, Globodera rostochiensis. International Journal for Parasitology15: 441–445. Hatched second-stage juveniles of Globodera rostochiensis can survive sub-zero temperatures by supercooling when not in contact with water. When frozen in water free juveniles cannot survive ice seeding across the cuticle and concomitant freezing of their body contents. Unhatched juveniles can survive in water, probably because the egg-shell protects the juvenile from ice seeding across from the medium; in this state juveniles survive by supercooling.     

Dispersal patterns of an Australian gall-forming thrips and its host tree (Oncothrips tepperi and Acacia oswaldii )

Abstract. 1. Clark and Evans' nearest-neighbour method was used to evaluate the distribution pattern of Acacia oswaldii and Oncothrips tepperi populations.
2. A random distribution pattern was supported statistically for both the host trees and trees that were parasitised by O. tepperi .
3. It is therefore likely that dispersal distances of colonising thrips are large enough to be able to traverse the 1 km² study site.     

Disrupting the stem cell niche: good seeds in bad soil

Stem cells reside in a microenvironment or niche that is critical for stem cell maintenance and regulation. But what happens when a stem cell niche is disrupted? In this issue of Cell, two reports (Walkley et al., 2007a, 2007b) demonstrate in mice that alterations in the niche for hematopoietic stem cells lead to the development of myeloproliferative disease.     

N6-Cycloalkyl-2-substituted adenosine derivatives as selective, high affinity adenosine A1 receptor agonists

A series of new selective, high affinity A(1)-AdoR agonists is reported. Compound 23 that incorporated a carboxylic acid functionality in the 4-position of the pyrazole ring displayed K(iL) value of 1 nM for the A(1)-AdoR and >5000-fold selectivity over the A(3) and A(2A)-AdoRs. In addition, compound 19 that incorporated a carboxamide functionality in the 4-position of the pyrazole ring displayed subnanomolar affinity for the A(1)-AdoR (K(iL)=0.6 nM) and >600-fold selectivity over the A(3) and A(2A)-AdoRs.