The role of COBRA‐LIKE 2 function,as part of the complex network of interacting pathways regulating Arabidopsis seed mucilage polysaccharide matrix organization

The production of hydrophilic mucilage along the course of seed coat epidermal cell differentiation is a common adaptation in angiosperms. Previous studies have identified COBRA‐LIKE 2 (COBL2), a member of the COBRA‐LIKE gene family, as a novel component required for crystalline cellulose deposition in seed coat epidermal cells. In recent years, Arabidopsis seed coat epidermal cells (SCEs), also called mucilage secretory cells, have emerged as a powerful model system for the study of plant cell wall components biosynthesis, secretion, assembly and de muro modification. Despite accumulating data, the molecular mechanism of COBL function remains largely unknown. In the current research, we utilized genetic interactions to study the role of COBL2 as part of the protein network required for seed mucilage production. Using correlative phenotyping of structural and biochemical characteristics, unique features of the cobl2 extruded mucilage are revealed, including: ‘unraveled’ ray morphology, loss of primary cell wall ‘pyramidal’ organization, reduced Ruthenium red staining intensity of the adherent mucilage layer, and increased levels of the monosaccharides arabinose and galactose. Examination of the cobl2cesa5 double mutant provides insight into the interface between COBL function and cellulose deposition. Additionally, genetic interactions between cobl2 and fei1fei2 as well as between each of these mutants to mucilage‐modified 2 (mum2) suggest that COBL2 functions independently of the FEI‐SOS pathway. Altogether, the presented data place COBL2 within the complex protein network required for cell wall deposition in the context of seed mucilage and introduce new methodology expending the seed mucilage phenotyping toolbox.     

Development of a protein–ligand-binding site prediction method based on interaction energy and sequence conservation

We present a new method for predicting protein–ligand-binding sites based on protein three-dimensional structure and amino acid conservation. This method involves calculation of the van der Waals interaction energy between a protein and many probes placed on the protein surface and subsequent clustering of the probes with low interaction energies to identify the most energetically favorable locus. In addition, it uses amino acid conservation among homologous proteins. Ligand-binding sites were predicted by combining the interaction energy and the amino acid conservation score. The performance of our prediction method was evaluated using a non-redundant dataset of 348 ligand-bound and ligand-unbound protein structure pairs, constructed by filtering entries in a ligand-binding site structure database, LigASite. Ligand-bound structure prediction (bound prediction) indicated that 74.0 % of predicted ligand-binding sites overlapped with real ligand-binding sites by over 25 % of their volume. Ligand-unbound structure prediction (unbound prediction) indicated that 73.9 % of predicted ligand-binding residues overlapped with real ligand-binding residues. The amino acid conservation score improved the average prediction accuracy by 17.0 and 17.6 points for the bound and unbound predictions, respectively. These results demonstrate the effectiveness of the combined use of the interaction energy and amino acid conservation in the ligand-binding site prediction.     

Lifetime risk of diabetes among First Nations and non–First Nations people

Background:Lifetime risk is a relatively straightforward measure used to communicate disease burden, representing the cumulative risk of an outcome during the remainder of an individual’s life starting from a disease-free index age. We estimated the lifetime risk of diabetes among men and women in both First Nations and non–First Nations populations using a cohort of adults in a single Canadian province.Methods:We used a population-based cohort consisting of Alberta residents from 1997 to 2008 who were free of diabetes at cohort entry to estimate the lifetime risk of diabetes among First Nations and non–First Nations people. We calculated age-specific incidence rates with the person-year method in 5-year bands. We estimated the sex- and index-age–specific lifetime risk of incident diabetes, after adjusting for the competing risk of death.Results:The cohort included 70 631 First Nations and 2 732 214 non–First Nations people aged 18 years or older. The lifetime risk of diabetes at 20 years of age was 75.6% among men and 87.3% among women in the First Nations group, as compared with 55.6% among men and 46.5% among women in the non–First Nations group. The risk was higher among First Nations people than among non–First Nations people for all index ages and for both sexes. Among non–First Nations people, men had a higher lifetime risk of diabetes than women across all index ages. In contrast, among First Nations people, women had a higher lifetime risk than men across all index ages.Interpretation:About 8 in 10 First Nations people and about 5 in 10 non–First Nations people of young age will develop diabetes in their remaining lifetime. These population-based estimates may help health care planners and decision-makers set priorities and increase public awareness and interest in the prevention of diabetes.Diabetes mellitus is a major health problem worldwide and is associated with increased morbidity, mortality, life expectancy and health care costs.^1–4 The prevalence of diabetes in Canada has increased more than twofold over the past decade.⁵ Currently, the disease affects almost 2.4 million Canadians,⁶ and its management, along with that of associated complications, costs more than $9 billion annually.⁷ The burden of diabetes is particularly high among First Nations people in Canada, with prevalence rates 3–5 times higher than those among non–First Nations people.⁸Reducing the risk of type 2 diabetes will require a broad set of population-based and individual-level interventions that target diabetogenic aspects of lifestyle, as well as social determinants of health. The changes required to achieve these objectives will need buy-in from a wide range of stakeholders. Thus, it will be important to communicate risk in a way that is understood by the general population and by health authorities.Although estimates of incidence and prevalence provide important information about the burden of a disease in the community, they do not provide adequate information regarding the perspective of risk at the individual level. Lifetime risk (the probability of a disease-free individual developing the disease during his or her remaining lifespan) may be more informative for the general population and for decision-makers. Life-table modelling techniques use incidence and mortality data to estimate the lifetime risk of diabetes. This important assessment of the disease burden of diabetes has been undertaken in a few studies,^9–11 but it has not been done in Canada. The need for such estimates is particularly relevant given the higher prevalence of diabetes among First Nations people in Canada.We estimated the lifetime risk of diabetes among men and women in both First Nations and non–First Nations populations using a cohort of adults residing in a single Canadian province.     

Histological and carbohydrate histochemical studies of the nasal mucosa of sheep in Saudi Arabia with special reference to its glandular tissue

The histology and carbohydrate histochemistry of the nasal mucosa with attention to glandular tissue had been studied in 7 heads of sheep. Tissues were taken from vestibular region, septum at level of the alar fold, rostral portion of nasal conchae, caudal portion of nasal conchae, middle portion of septum and ethmoidal conchae region. Stratified squamous nonkeratinized epithelium was observed covering the vestibular region. The propria-submucosa of the nasal vestibule was richly permeated with glands having affinity for PAS and non-alcianophilic. The post-vestibular portion of the nasal cavity was lined by transitional epithelium and caudal to it, stratified columnar nonciliated epithelium was noticed. The respiratory epithelium covered the caudal half of the nasal conchae and the major portion of the septum as well as the recesses of the ethmoidal conchae. The glands associated with the respiratory mucosa were thick, coiled and tubular, containing both nonalcianophilic PAS positive and alcianophilic PAS positive cells. The olfactory mucosa covered the ethmoidal conchae and showed predominant serous glands. The results were discussed with that given for other mammals and in regard to the respiratory functions of the nasal mucosa.     

Effect of cultivation conditions on proteinase production byLactobacillus murinus

Proteinase production byLactobacillus murinus was influenced by temperature, glucose concentration, initial pH and nitrogen sources. Maximum proteinase production occurred at 45°C, pH 6.6 and with 0.5 % (W/V) glucose. Tryptone, peptone and gelatin inhibited it. Member of theScientific Researcher’s Career of theConsejo Nacional de Investigaciones Cientificas y Técnicas (Conicet), Argentina.     

Teratology of intravaginally administered contraceptive jelly containing octoxynol-9 in rats

Octoxynol-9, a nonionic surfactant used as a spermicidal agent in ORTHO-GYNOL (registered trademark) Contraceptive Jelly (Ortho Pharmaceutical Corporation, Raritan, NJ), was administered intravaginally to pregnant Sprague Dawley COBS CD rats at dosages of 0.5 mg/kg/day and 5 mg/kg/day (two-thirds and six times the clinical dosage) on days 6-15 of gestation in order to assess its teratogenic potential. Untreated, sham, and vehicle control groups were also incorporated into the study protocol. No meaningful differences were observed between the treated and control groups in maternal toxicity, maternal reproductive parameters, fetal toxicity, and the incidence of external, visceral, and skeletal malformations or developmental variations. It is concluded that octoxynol-9 is not embryotoxic or teratogenic when administered intravaginally to rats during organogenesis.     

Reduction of aflatoxin B1 levels by sheep saliva

This study determined the decrease of aflatoxin B₁ by sheep saliva at concentrations of 150 and 300 μg aflatoxin B-₁/L saliva. Analyses for aflatoxins B₁, M₁, and aflatoxicol (R₀) were performed after 2, 4, 6, 24, and 48 hours of incubation. Aflatoxin M₁ and R₀ were not detected and only residues of aflatoxin B₁ were found. 4 to 13% of aflatoxin B₁ were decomposed by sheep’s saliva within 2 hrs and 33 to 43% of aflatoxin B₁ after 24 hrs. Decomposition was affected by the aflatoxin concentration. Decrease of aflatoxin B₁ at 2, 4, 6 hrs was nearly three times higher at the low concentration (150 ppb) compared to the high concentration (300 ppb). After 48 hrs incubation more than 80% of the initial aflatoxin B₁ had been decomposed by the saliva.     

Aflatoxin in human and camel milk in Abu Dhabi,United Arab Emirates

During an initial survey, using thin layer chromatography, 10 of 64 samples of mothers’ breast milk, collected from donors at the Corniche Maternity Hospital and the Al-Nehyan Clinic for Maternity and Childhood, were found to contain Aflatoxin M₁ at concentrations ranging from 0.3 to 1.3 ng mL^?1. A second survey using HPLC showed Aflatoxin M₁ at concentrations ranging from 7 to 23 pg mL^?1 in all of the 15 samples collected. 6 of 20 samples of camel milk collected from several sources in Abu Dhabi were also found to contain Aflatoxin M₁ at levels ranging from 0.25 to 0.8 ng mL^?1.     

Distributed Clone Detection in Static Wireless Sensor Networks: Random Walk with Network Division

Wireless Sensor Networks (WSNs) are vulnerable to clone attacks or node replication attacks as they are deployed in hostile and unattended environments where they are deprived of physical protection, lacking physical tamper-resistance of sensor nodes. As a result, an adversary can easily capture and compromise sensor nodes and after replicating them, he inserts arbitrary number of clones/replicas into the network. If these clones are not efficiently detected, an adversary can be further capable to mount a wide variety of internal attacks which can emasculate the various protocols and sensor applications. Several solutions have been proposed in the literature to address the crucial problem of clone detection, which are not satisfactory as they suffer from some serious drawbacks. In this paper we propose a novel distributed solution called Random Walk with Network Division (RWND) for the detection of node replication attack in static WSNs which is based on claimer-reporter-witness framework and combines a simple random walk with network division. RWND detects clone(s) by following a claimer-reporter-witness framework and a random walk is employed within each area for the selection of witness nodes. Splitting the network into levels and areas makes clone detection more efficient and the high security of witness nodes is ensured with moderate communication and memory overheads. Our simulation results show that RWND outperforms the existing witness node based strategies with moderate communication and memory overheads.