Prey location by Oechalia schellembergii

A total of 548 spiders (Gnaphosidae, Clubionidae, Thomisidae, Philodromidae, Salticidae, Lycosidae, Pisauridae, Linyphiidae) from three sand dune grassland sites were tested serologically for feeding on the grasshoppers, Chorthippus brunneus (Thunberg) and Myrmeleotettix maculatus (Thunberg). Lycosidae were the most commonly tested species and gave the greatest proportion of positive tests. Laboratory observations suggest that predation in the field was predominantly on first instar grasshoppers.

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Résumé Afin d'améliorer la connaissance de l'importance des prédateurs dans la biologie des populations de criquets (Orthoptères; Acrididae), les araignées de trois pelouses sur dunes de sable ont été examinées sérologiquement pour estimer leur consommation des populations sympatriques de Chorthippus brunneus Thunberg et Myrmeleotettix maculatus Thunberg. Au total, 548 araignées (Gnaphosidae, Clubionidae, Thomisidae, Philodromidae, Salticidae, Lycosidae, Pisauridae, Linyphiidae) ont été récoltées à la main ou par piège pendant la période d'éclosion des ufs de criquets. Les Lycosidae ont été le plus fréquemment observées (90,5% de toutes les récoltes) et ont donné la plus forte proportion d'individus positifs (jusqu'à 32,3%). Les expériences d'alimentation en laboratoire suggèrent que, dans la nature, les Lycosidae sont les plus actives contre les criquets du premier stade.

     

Predation by three hemipterans:Tropiconabis nigrolineatus,Oechalia schellenbergii andCermatulus nasalis,onHeliothis punctiger larvae in two types of searching arenas

Three species of hemipteran predators preyed differently upon 1^st instarHeliothis punctiger Wallengren larvae.Cermatulus nasalis consumed more larvae thanOechalia schellenbergii which consumed more larvae thanTropiconabis nigrolineatus. All the species consumed significantly less 1^st instar larvae on plants than what they consumed in Petri-dishes. Fifth instar predators showed significant differences in terms of prey consumption due to sex independent of searching conditions. Only 4^th and 5^th instars ofT. nigrolineatus attacked and captured 2^nd instars ofH. punctiger larvae. The other 2 species however readily attacked and consumed 2^nd instarH. punctiger larvae. Their prey consumption was similar in Petri-dishes and on plants. Only 5^th instars ofT. nigrolineatus could subdue and capture 3^rd instarH. punctiger larvae. Second instar pentatomids captured just one 3^rd instar larva but older instars killed and ate more. Fourth instarH. punctiger larvae were immune to attacks by allT. nigrolineatus and younger pentatomids due to their defense ploys but 5^th instar pentatomids could subdue and capture them. None of the predators captured 5^th instarH. punctiger larvae except few 5^th instar females ofC. naslis andO. schellenbergii.      

Expression levels of the metalloproteinase ADAM8 critically regulate proliferation,migration and malignant signalling events in hepatoma cells

Hepatocellular carcinoma (HCC) is one of the most common metastatic tumours. Tumour growth and metastasis depend on the induction of cell proliferation and migration by various mediators. Here, we report that the A Disintegrin and Metalloproteinase (ADAM) 8 is highly expressed in murine HCC tissues as well as in murine and human hepatoma cell lines Hepa1-6 and HepG2, respectively. To establish a dose-dependent role of different ADAM8 expression levels for HCC progression, ADAM8 expression was either reduced via shRNA- or siRNA-mediated knockdown or increased by using a retroviral overexpression vector. These two complementary approaches revealed that ADAM8 expression levels correlated positively with proliferation, clonogenicity, migration and matrix invasion and negatively with apoptosis of hepatoma cells. Furthermore, the analysis of pro-migratory and proliferative signalling pathways revealed that ADAM8 expression level was positively associated with expression of β1 integrin as well as with the activation of focal adhesion kinase (FAK), mitogen-activated protein kinase (MAPK), Src kinase and Rho A GTPase. Finally, up-regulation of promigatory signalling and cell migration was also seen with a proteolytically inactive ADAM8 mutant. These findings reveal that ADAM8 is critically up-regulated in hepatoma cells contributes to cell proliferation and survival and furthermore induces pro-migratory signalling pathways independently of its proteolytic activity. By this, ADAM8 can promote cell functions most relevant for HCC growth and metastasis.     

The genetic association study of TP53 polymorphisms in Saudi obese patients

Obesity is a multifactorial metabolic disorder characterized by low grade chronic inflammation. Rare and novel mutations in genes which are vital in several key pathways have been reported to alter the energy expenditure which regulates body weight. The TP53 or p53 gene plays a prominent role in regulating various metabolic activities such as glycolysis, lipolysis, and glycogen synthesis. Recent genome-wide association studies reported that tumor suppressor gene p53 variants play a critical role in the predisposition of type 2 diabetes and obesity. Till date, no reports are available from the Arabian population; hence the present study was intended to assess the association between p53 variants with risk of obesity development in the Saudi population. We have selected three p53 polymorphisms, rs1642785 (C > G), and rs9894946 (A > G), and rs1042522 (Pro72Arg; C > G) and assessed their association with obesity risk in the Saudi population. Phenotypic and biochemical parameters were also evaluated to check their association with p53 genotypes and obesity. Genotyping was carried out on 136 obese and 122 normal samples. We observed that there is significantly increased prevalence p52 Pro72Arg (rs1042522) polymorphism in obese persons when compared to controls at GG genotype in overall comparison (OR: 2.169, 95% CI: 1.086-4.334, p = 0.02716). Male obese subjects showed three-fold higher risk at GG genotype (OR: 3.275, 95% CI: 1.230-8.716, p = 0.01560) and two-fold risk at G allele (OR: 1.827, 95% CI: 1.128-2.958, p = 0.01388) of p53 variant Pro72Arg respectively. This variant has also shown significant influence on cholesterol, LDL level, and random insulin levels in obese subjects (p ≤ 0.05). In conclusion, p53 Pro72Arg variant is highly prevalent among obese individuals and may act as a genetic modifier for obesity development among Saudis.     

Study of genetic divergence among wheat genotypes through random amplified polymorphic DNA

The degree of genetic divergence was estimated in seven wheat genotypes, six exotic genotypes and one local variety, through random amplified polymorphic DNA methodology. A total of 112 DNA fragments were generated by the 15 random primers, with an average of about 7.4 bands per primer. Among the 112, 50 fragments showed polymorphism among the seven wheat genotypes. Nei and Li's similarity matrix ranged from 86.2 to 93.0%, which indicated a narrow genetic base among the genotypes. The maximum similarity, 93.0%, was observed between 12WLRG/1-12 and WL-43. The local variety, Chenab-70, showed the lowest similarity with the exotic types. We conclude that random amplified polymorphic DNA analysis can be used for the characterization and grouping of wheat genotypes; these results will be helpful in our wheat breeding program.     

Cloning and characterization of Kin5, a novel Tetrahymena ciliary kinesin II

Two Tetrahymena kinesin-like proteins (klps) of the kinesin II subfamily, Kin1 and Kin2, were first identified by Brown et al. [1999: Mol Biol Cell 10: 3081-3096] and shown to be involved in ciliary morphogenesis probably as molecular motors in intraciliary transport (ICT). Using Tetrahymena genomic DNA as a template, we cloned Kin5, another kinesin II subfamily member. Kin5 is upregulated upon deciliation, suggesting that Kin5 is a ciliary protein. Kin5 is most closely related to Osm3, a Caenorhabditis elegans kinesin II; Osm3 and Kin5 have a 56% identity, which rises to 60.4% in the motor domain and a 45% identity in a 60 amino acid region of the C-terminal FERM (4.1, Ezrin, Radixin, Moesin) domain, not present in Kin1 or Kin2, which we hypothesize to be a critical domain either for dimerization or for cargo recognition in ICT. An antibody to a peptide sequence from the tail region of Kin5 localizes in a punctate pattern along the ciliary axoneme, colocalizing with an antibody to the raft protein IFT139. These findings suggest that Kin5 is an ICT motor like Osm3. Osm3 orthologs apparently transport membrane proteins and Kin5 may be the homodimeric kinesin II that performs this function in Tetrahymena cilia.     

Influence of Environmental Factors,Cultural Practices,and Herbicide Application on Seed Germination and Emergence Ecology of Ischaemum rugosum Salisb

Ischaemum rugosum Salisb. (Saramolla grass) is a noxious weed of rice that is difficult to control by chemical or mechanical means once established. A study was conducted to determine the effect of light, temperature, salt, drought, flooding, rice residue mulch, burial depth, and pre-emergence herbicides on seed germination and emergence of I. rugosum. Germination was stimulated by light and inhibited under complete darkness. Optimum temperature for germination was 30/20°C (97.5% germination). Germination reduced from 31 to 3.5% when the osmotic potential of the growing medium decreased from -0.1 to -0.6 MPa and no germination occurred at -0.8 MPa. Germination was 18 and 0.5% at 50 and 100 mM NaCl concentrations, respectively, but was completely inhibited at 150 mM or higher. Residue application at 1–6 t ha^-1 reduced weed emergence by 35–88% and shoot biomass by 55–95%. The efficacy of pre-emergence herbicides increased with increasing application rates and decreased with increasing rice residue mulching. The efficacy of herbicides was in the order of oxadiazon> pendimethalin> pretilachlor. At 6 t ha^-1, all herbicides, regardless of rates, did not differ from the control treatment. I. rugosum seeds buried at 2 cm or deeper did not emerge; however, they emerged by 4.5 and 0.5% at 0.5 and 1 cm depths, respectively, compared to the 39% germination for soil surface seeding. Flooding at 4 DAS or earlier reduced seedling emergence and shoot biomass while flooding at 8 DAS reduced only seedling emergence. The depth and timing of flooding independently reduced root biomass. Flooding at 4 and 6 cm depths reduced the root biomass. Relative to flooding on the day of sowing, flooding at 8 DAS increased root biomass by 89%. Similarly, flooding on the day of sowing and at 2 DAS reduced the root–shoot biomass ratio. Under the no-flood treatment, increasing rates of pretilachlor from 0.075 to 0.3 kg ai ha^-1 reduced weed emergence by 61–79%. At the flooding depth of 2–4 cm, pretilachlor reduced weed emergence and shoot and root biomass, but the differences across rates were non-significant. Information generated in this study will be helpful in developing integrated weed management strategies for managing this weed.