Telomere length and risk of melanoma,squamous cell carcinoma,and basal cell carcinoma

Background: Telomeres help maintain chromosomal structure and may influence tumorigenesis. We examined the association between telomere length and skin cancer in a clinic-based case-control study of 198 melanoma cases, 136 squamous cell carcinoma (SCC) cases, 185 basal cell carcinoma (BCC) cases, and 372 healthy controls. Methods: Cases were histologically confirmed patients treated at the Moffitt Cancer Center and University of South Florida Dermatology Clinic in Tampa, FL. Controls self-reported no history of cancer and underwent a skin cancer screening exam at study enrollment to rule out the presence of skin cancer. Quantitative real time PCR was used to measure telomere length in peripheral blood samples. Results: Melanoma patients had longer telomeres than controls (odds ratio (OR) = 3.75; 95% confidence interval (CI): 2.02–6.94 for highest versus lowest tertile) (P for trend = <0.0001). In contrast, longer telomere length was significantly inversely associated with SCC (OR = 0.01; 95% CI: 0.00–0.05 for highest versus lowest tertile) (P for trend = <0.0001) and BCC (OR = 0.10; 95% CI: 0.06–0.19 for highest versus lowest tertile) (P for trend = <0.0001). Conclusion: Telomere length may be involved in the development of skin cancer, although the effect on cancer risk differs for melanoma and non-melanoma carcinomas. Our findings suggest that long telomere length is positively associated with melanoma while inversely associated with SCC and BCC.     

Identification and Characterisation of the RalA-ERp57 Interaction: Evidence for GDI Activity of ERp57

RalA is a membrane-associated small GTPase that regulates vesicle trafficking. Here we identify a specific interaction between RalA and ERp57, an oxidoreductase and signalling protein. ERp57 bound specifically to the GDP-bound form of RalA, but not the GTP-bound form, and inhibited the dissociation of GDP from RalA in vitro. These activities were inhibited by reducing agents, but no disulphide bonds were detected between RalA and ERp57. Mutation of all four of ERp57’s active site cysteine residues blocked sensitivity to reducing agents, suggesting that redox-dependent conformational changes in ERp57 affect binding to RalA. Mutations in the switch II region of the GTPase domain of RalA specifically reduced or abolished binding to ERp57, but did not block GTP-specific binding to known RalA effectors, the exocyst and RalBP1. Oxidative treatment of A431 cells with H₂O₂ inhibited cellular RalA activity, and the effect was exacerbated by expression of recombinant ERp57. The oxidative treatment significantly increased the amount of RalA localised to the cytosol. These findings suggest that ERp57 regulates RalA signalling by acting as a redox-sensitive guanine-nucleotide dissociation inhibitor (RalGDI).     

Landscape correlates of forest plant invasions: A high‐resolution analysis across the eastern United States

Aim

Invasive species occurrence is often related to the anthropogenic context of a given area. Quantifying the effects of roads is of particular interest as roads are a major vector for invasion. Our objective was to further quantify the effects of roads on forest plant invasion through a macroscale, high‐resolution investigation to assist effective invasion control and mitigation.

Location

Eastern United States.

Methods

Using invasive plant data from 23,039 forest inventory plots in 13 ecological provinces, we employed logistic regression to relate the odds of invasion to distance from a road, with adjustments for broadscale differences attributable to ecological provinces, and local scale differences in productivity, forest fragmentation and land use.

Results

The overall proportion (P) of invaded plots was 0.58 (0.65 for plots within 50 m of a road), and the highest odds (P/1 ? P) of invasion were found in relatively more productive, fragmented forest in landscapes with more than 10% agriculture or developed land cover. Wald chi‐square statistics indicated the best predictor of the odds of invasion was ecological province, followed by land use, productivity, forest fragmentation and distance from a road. Depending on the province, the adjusted odds of invasion decreased by up to 23% (typically 4%–10%) per 100 m distance from a road. The adjusted probability of invasion approached zero in only three provinces, for the least productive, least fragmented forest that was at least 2,000 m from a road in landscapes with less than 10% agricultural or developed land cover.

Main conclusions

In the eastern United States, the existence of a nearby road is less important than the landscape context associated with the road. A purely road‐mediated effect has little practical meaning because anthropogenic activities and roads are pervasive and confounded.

     

In vitro effect of some Indian honeys on Staphylococcus aureus from wounds

Staphylococcus aureus is the most frequently isolated pathogen from wounds with multiple resistances to antibiotics. Honey has been demonstrated and reported to be effective antibacterial agent on Gram positive and Gram negative organisms. Hence, the present study was conducted to evaluate the in vitro antibacterial effect of Indian honeys on Staphylococcus aureus obtained from wounds. A total of 123 Staphylococcus aureus isolates along with ATCC 25923 were categorized as sensitive, multi drug resistant (MDR) and non-MDR strains. Out of total nine Indian honeys (three each of unifloral, multifloral and branded marketed honey) used, three unifloral and three multifloral honey samples showed antibacterial activity against all the organisms tested by Agar diffusion method but not the branded marketed honeys. The MIC values of all honey samples for all studied Staphylococcus aureus isolates ranged between 5-15% (v/v). Unifloral honey samples showed higher antibacterial activity than multifloral honey. The single sample of Jambhul honey showed the highest activity. Thus, Indian honeys were found to be effective for their antimicrobial activity on sensitive, non-MDR, MDR and ATCC strains of S. aureus.     

Morphometric and allozyme variation in central and southern Greek populations ofMicrotus (Terricola) thomasi

The endemic Balkan vole taxonMicrotus (Terricola) thomasi (Barrett-Hamilton, 1903) exhibits great karyological variability in Greece. In this study, populations belonging to two different karyotypic forms (‘atticus’ and ‘thomasi’) are examined both morphometrically and electrophoretically. A total of 140 individuals ofM. (T.) thomasi were collected from 6 localities of south and central Greece. For the morphometric analysis, 27 variables (external body and cranial characters) were examined and evaluated according to multivariate analyses (PCA, MANOVA, CVA and CLUS). For the electrophoretic analysis, 18 putative genetic loci were examined and the allozymic data were treated by the biostatistical package BIOSYS-1. According to the results obtained, all the populations studied show little overall morphometric variability, whereas they are characterized by high electrophoretic variability. The populations studied are not grouped according to the karyotypic form. In almost all the cases, in the two UPGMA-dendrograms plotted according to morphometric and electrophoretic distances (Mahalanobis’ and Nei’s distances, respectively), the populations branching together belong to different karyotypic forms. Conclusively, the morphometric and electrophoretic results of this study revealed that the two karyotypic forms should not be considered separate species or subspecies, as it has been proposed by some authors in the past, and the populations studied can be considered only as different local populations of the rather variable vole speciesM. (T.) thomasi.     

A Moricandia arvensis– based cytoplasmic male sterility and fertility restoration system in Brassica juncea

 A cytoplasmic male-sterility system has been developed in mustard (Brassica juncea) following repeated backcrossings of the somatic hybrid Moricandia arvensis (2n=28, MM)+B. juncea (2n=36, AABB), carrying mitochondria and chloroplasts from M. arvensis, to Brassica juncea. Cytoplasmic male-sterile (CMS) plants are similar to normal B. juncea; however, the leaves exhibit severe chlorosis resulting in delayed flowering. Flowers are normal with slender, non-dehiscent anthers and excellent nectaries. CMS plants show regular meiosis with pollen degeneration occurring during microsporogenesis. Female fertility was normal. Genetic information for fertility restoration was introgressed following the development of a M. arvensis monosomic addition line on CMS B. juncea. The additional chromosome paired allosyndetically with one of the B. juncea bivalents and allowed introgression. The putative restorer plant also exhibited severe chlorosis similar to CMS plants but possessed 89% and 73% pollen and seed fertility, respectively, which subsequently increased to 96% and 87% in the selfed progeny. The progeny of the cross of CMS line with the restorer line MJR-15, segregated into 1 fertile : 1 sterile. The CMS (Moricandia) B. juncea, the restorer (MJR-15), and fertility restored F₁ plants possess similar cytoplasmic organellar genomes as revealed by ‘Southern’ analysis. Received: 17 September 1997 / Accepted: 18 February 1998     

Characterization of Bacillus thuringiensis Cry toxin binding novel GPI anchored aminopeptidase from fat body of the moth Spodoptera litura

Aminopeptidase N (APN) isoforms were identified as candidate receptors for Bacillus thuringiensis Cry toxins from the midgut of several insect species. In this study a partial cDNA encoding aminopeptidase (slfbAPN) was cloned from fat body of the moth Spodoptera litura. In the deduced amino acid sequence the characteristic metallopeptidase sequences, HEXXHX₁₈E and GAMENWG were conserved but the sequence showed only 33–39% identity to other insect APNs, which were also reported to be Cry toxin receptors. The presence of a putative GPI anchor signal sequence at the C-terminus indicated that it is a membrane-anchored protein. The slfbAPN expression was restricted to the fat body as suggested by northern blot analysis of different tissues. Biochemical analyses including immunoblotting, ligand blotting and lectin blotting, demonstrated that slfbAPN is a membrane-anchored glycoprotein in the fat body and it binds to Cry toxins. The nucleotide sequence shown here has been submitted to the GenBank sequence data bank and is available under accession number EF372603.     

Excessive zinc in diet induces leptin resistance in Wistar rat through increased uptake of nutrients at intestinal level

ProjectThe ob gene has either been found to be mutant defective resulting in a deficiency of its product leptin or leptin has been found to be resistant to its receptors in obese human and rodents. The factors inducing leptin resistance have not been identified. Since excessive bioavailability of Zn has been implicated in obesity, we investigated if its excess in diet induces leptin resistance.ProcedureFor the investigations, three groups of Wistar rats were included in this study and they were fed on equicalories semi synthetic basal diet containing 20 mg, 40 mg or 80 mg Zn/kg diet for 120 days. There after they were sacrificed for hormonal status and intestinal investigations.ResultsThe data of this study revealed that the food intake, gain in body weight, serum leptin, glucose, insulin, cortisol increased with increased Zn concentration in diet. TEM study showed a positive correlation between Zn concentration in diet and number of microvilli/unit surface area of the mucosal epithelial cells of the intestine.ConclusionThe results of this study suggest that excessive bioavailability of Zn induces leptin resistance through increased uptake of nutrients at intestinal level, leading to the growth of the fat cells which aggravated the leptin synthesis and its release in the blood stream. In spite of its higher circulating level, it was unable to reduce the food intake and gain in body weight in Zn treated rats equivalent to the control group.     

Constitutive expression of mustard annexin, <Emphasis Type="Italic">AnnBj1</Emphasis> enhances abiotic stress tolerance and fiber quality in cotton under stress

Annexins belong to a multigene family of Ca²⁺ dependent, phospholipid and cytoskeleton binding proteins. They have been shown to be upregulated under various stress conditions. We generated transgenic cotton plants expressing mustard annexin (AnnBj1), which showed enhanced tolerance towards different abiotic stress treatments like sodium chloride, mannitol, polyethylene glycol and hydrogen peroxide. The tolerance to these treatments was associated with decreased hydrogen peroxide levels and enhanced total peroxidase activity, enhanced content of osmoprotectants- proline and sucrose in transgenic plants. They showed higher retention of total chlorophyll and reduced TBARS in leaf disc assays with stress treatments, and decreased hydrogen peroxide accumulation in the stomatal guard cells when compared to their wild type counterparts. They also showed significantly enhanced fresh weight, relative water content, dry weight under stress. Treatment with sodium chloride resulted in enhanced expression of genes for ∆-pyrroline-5-carboxylase synthetase in leaves, and sucrose phosphate synthase, sucrose synthase and cellulose synthase A in the leaves and fibers of transgenic plants. The transgenic plants maintained normal seed development, fiber quality and cellulose content under stress.