Multi-level on-demand access control for flexible data sharing in cloud

The exponential growth of data storage and sharing in cloud demands an efficient access control mechanism for flexible data sharing. Attribute-Based Encryption (ABE) is a promising cryptographic solution to share data among users in the cloud. But it suffers from user revocation, attribute revocation, forward secrecy and backward secrecy issues. Communication and computation overhead is more due to the linear variation in the size of ciphertext and the secret key with respect to the number of attributes. In this paper, we investigate an on-demand access control for flexible sharing of secure data among randomly selected users. It is a tunable access control mechanism for the flexible sharing of ciphertext classes in the cloud. It delegates the decryption rights of any set of ciphertext classes among the users only if their attributes are satisfied with the access policy associated with ciphertext and if they should possess a compact key corresponding to the intended set of ciphertext classes. It produces a constant size ciphertext and a compact secret key to efficiently utilize the storage space and reduce the communication cost. The compact key aggregates the power of secret keys used to encrypt the outsourced data. This method flexibly shares the ciphertext classes among the randomly selected users with a specific set of attributes. All other ciphertext classes outside the set remain confidential. It allows dynamic data updates by verifying the data manipulation privilege of users with the help of claim policy. The proposed scheme provides access control of varying granularity, at user-level, at file-level, and attribute-level. Granularity levels can be chosen based on applications and user demands. Hence, it is a multi-level, tunable access control over the shared data. It is very useful for secure data storage. This scheme tackles user revocation and attribute revocation problems so that, it allows the data owner to revoke a specific user or a group of users. It prevents forward and backward secrecy issues.

     

Smoking related risk involved in individuals carrying genetic variants of CYP1A1 gene in head and neck cancer

Background: CYP1A1 is one of the commonest genes which had been widely investigated to find the risk of various malignancies in different ethnic groups. The polymorphism in these genes with a combination of environmental exposure has been hypothesized to confer a differential risk of cancer for individuals carrying these genetic variants. Based on this model, individuals with higher CYP1A1 activity would be at increased risk of cancer when exposed to high levels of smoke components. The proposed mechanism involves cytochrome P450 1A1 (CYP1A1), a gene that is inducible by xenobiotics to produce genetic susceptibility for malignancies. Patients and procedures: We performed a case–control study in 205 cases with histopathologically confirmed squamous cell carcinoma of head and neck and reported habits of bidi or cigarettes smoking and 245 similar controls to investigate the role of CYP1A1 polymorphisms in the risk of head and neck cancers especially among smokers of Hyderabad Indian population. Venous blood samples (5 ml) were collected from patients and control groups; genomic DNA was extracted and used for polymerase chain reaction (PCR) to determine the genotypes. RFLP assays were designed to detect each of the variant CYP1A1 alleles. Results and discussion: CYP1A1m1/m1 genotype (OR = 8.12, 95% CI: 3.27–21.30) and CYP1A1w1/m1 showed elevated risk when compared with CYP1A1w1/w1. Similarly CYP1A1w2/m2 (OR = 1.58, 95% CI: 0.94–2.67) and CYP1A1m2/m2 (OR = 6.31, 95% CI: 2.74–18.69) genotypes also showed elevated risk when compared with CYP1A1w2/w2 genotype. This data demonstrated that smoking was a risk factor for head and neck cancers. The m2 mutations were in close linkage disequilibrium with the m1 mutations; 53% m1 mutants had the mutation in the m2 site. Conclusion: Those individuals carrying at least one CYP1A1 m1 or m2 variant allele were at a 2-fold elevated risk for head and neck cancer. Our data clearly demonstrates that CYP1A1 is an important determinant in susceptibility to tobacco-induced head and neck carcinogens and there is an association between genetic polymorphism in the CYP1A1 locus and elevated risk of the type of smoking among Indians. This appears to be a new and important prognostic and diagnostic marker for determining the risk of head and neck cancers genetically.     

Prevention of HCl-ethanol induced gastric mucosal injury in rats by Garcinia cambogia extract and its possible mechanism of action

Oral pretreatment of rats with G. cambogia fruit extract (1 g/kg body weight/day at interval of 7 and 15 days) protected gastric mucosa against HCl-ethanol induced damage by decreasing the volume and acidity of gastric juice. Increased lipid peroxidation, decreased activity of antioxidant enzymes, altered levels of protein and glycoproteins in the ulcerated mucosa, and gastric juice were maintained at near normal levels in G. cambogia pretreated rats. The results suggest the anti-ulcer activity of G. cambogia by virtue of its ability to decrease acidity and increase mucosal defense.     

The Effect of Pseudomonas fluorescens and Fusarium oxysporum f.sp. cubense on Induction of Defense Enzymes and Phenolics in Banana

The effect of Pseudomonas fluorescens treatment and Fusarium oxysporum f. sp. cubense inoculation on induction of phenylalanine ammonia-lyase (PAL), peroxidase (POX), chitinase, -1,3-glucanase and accumulation of phenolics in banana (Musa sp.) was studied. When banana roots were treated with P. fluorescens strain Pf10, a two-fold increase in phenolic content in leaf tissues was recorded 3 – 6 d after treatment. Challenge inoculation with F. oxysporum, the wilt pathogen, steeply increased the phenolic content in P. fluorescens-treated banana plants. Significant increase in POX activity was detected 6 – 9 d after P. fluorescens treatment. PAL, chitinase and -1,3-glucanase activities increased significantly from 3 d after P. fluorescens treatment and reached the maximum 6 d after treatment. Challenge inoculation with F. oxysporum further increased the enzyme activities. These results suggest that the enhanced activities of defense enzymes and elevated content of phenolics may contribute to bioprotection of banana plants against F. oxysporum.     

Effect of a polyherbal formulation, Ambrex, on butylated hydroxy toluene (BHT) induced toxicity in rats

Effect of polyherbal formulation Ambrex was evaluated in butylated hydroxytoluene (BHT) induced toxicity of lungs and liver in rats. Toxicity was produced by administering BHT (500 mg/kg/day) for 3 days. Lung damage was evidenced by elevated levels of broncho alveolar lavage fluid (BAL) parameters such as protein, lactate, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), acid phosphatase (ACP) and glucose-6-phosphate dehydrogenase (G6PDH). Liver damage was proved by elevated levels of serum protein and markers such as LDH, ALP, aspartate amino transferase (AST), alanine amino transferase (ALT), decreased level of lipid peroxides (LPO) in serum and glutathione (GSH) in liver. Administration of aqueous suspension of Ambrex (50 mg/kg orally) retained these elevated levels of BAL-protein, lactate, LDH, ALP, ACP, G6PDH and serum-protein, LDH, ALP, AST and ALT at near normal values. Decreased level of liver GSH was retained at near normalcy in Ambrex pretreated BHT-administered animals. There was no change in liver LPO in all the four groups.     

Gaseous ozone: A potent pest management strategy to control Callosobruchus maculatus (Coleoptera: Bruchidae) infesting green gram

Extending the storage life of legumes by protecting it from the Callosobruchus maculatus infestation is a major concern for the producers, processors and exporters. Legume processing industry requires “greener” alternatives to the conventional fumigants. Gaseous ozone has a great potential as an insect management strategy that is suited for this niche. Nevertheless, the efficacy of ozone against C. maculatus is yet unknown. A laboratory study was conducted to test the insecticidal effect of ozone in controlling the infestation of C. maculatus in green gram. We have determined the concentration of ozone exposure time–mortality relationship for all the stages of C. maculatus that were exposed to 500–1,500 ppmv ozone. The percentages of mortality for different stages of C. maculatus increased with the increase in ozone concentration and exposure time. It was documented that adult stage is least tolerant to ozone (500 ppmv for 274.40 min exposure required to kill 90%), whereas the most tolerant stage is pupa (500 ppmv for 1816.54 min is required to kill 90%). The results indicate that gaseous ozone is the attractive alternative to the synthetic fumigants.     

Metabolomics in early Alzheimer's disease: identification of altered plasma sphingolipidome using shotgun lipidomics

Background

The development of plasma biomarkers could facilitate early detection, risk assessment and therapeutic monitoring in Alzheimer''s disease (AD). Alterations in ceramides and sphingomyelins have been postulated to play a role in amyloidogensis and inflammatory stress related neuronal apoptosis; however few studies have conducted a comprehensive analysis of the sphingolipidome in AD plasma using analytical platforms with accuracy, sensitivity and reproducibility.

Methods and Findings

We prospectively analyzed plasma from 26 AD patients (mean MMSE 21) and 26 cognitively normal controls in a non-targeted approach using multi-dimensional mass spectrometry-based shotgun lipidomics [1], [2] to determine the levels of over 800 molecular species of lipids. These data were then correlated with diagnosis, apolipoprotein E4 genotype and cognitive performance. Plasma levels of species of sphingolipids were significantly altered in AD. Of the 33 sphingomyelin species tested, 8 molecular species, particularly those containing long aliphatic chains such as 22 and 24 carbon atoms, were significantly lower (p<0.05) in AD compared to controls. Levels of 2 ceramide species (N16:0 and N21:0) were significantly higher in AD (p<0.05) with a similar, but weaker, trend for 5 other species. Ratios of ceramide to sphingomyelin species containing identical fatty acyl chains differed significantly between AD patients and controls. MMSE scores were correlated with altered mass levels of both N20:2 SM and OH-N25:0 ceramides (p<0.004) though lipid abnormalities were observed in mild and moderate AD. Within AD subjects, there were also genotype specific differences.

Conclusions

In this prospective study, we used a sensitive multimodality platform to identify and characterize an essentially uniform but opposite pattern of disruption in sphingomyelin and ceramide mass levels in AD plasma. Given the role of brain sphingolipids in neuronal function, our findings provide new insights into the AD sphingolipidome and the potential use of metabolomic signatures as peripheral biomarkers.     

Xanthophylls are preferentially taken up compared with beta-carotene by retinal cells via a SRBI-dependent mechanism

The purpose of this study was to investigate the mechanisms by which carotenoids [xanthophylls vs. beta-carotene(beta-C)] are taken up by retinal pigment epithelial (RPE) cells. The human RPE cell line, ARPE-19, was used. When ARPE-19 cells were fully differentiated (7-9 weeks), the xanthophylls lutein (LUT) and zeaxanthin (ZEA) were taken up by cells to an extent 2-fold higher than beta-C (P < 0.05). At 9 weeks, cellular uptakes were 1.6, 2.5, and 3.2%, respectively, for beta-C, LUT, and ZEA. Similar extents were observed when carotenoids were delivered in either Tween 40 or "chylomicrons" produced by Caco-2 cells. Differentiated ARPE-19 cells did not exhibit any detectable beta-C 15,15'-oxygenase activity or convert exogenous beta-C into vitamin A. When using specific antibodies against the lipid transporters cluster determinant 36 (CD36) and scavenger receptor class B type I (SR-BI), cellular uptake of beta-C and ZEA were significantly decreased (40-60%) with anti-SR-BI but not with anti-CD36. Small interfering RNA transfection for SR-BI led to marked knockdown of SR-BI protein expression (approximately 90%), which resulted in decreased beta-C and ZEA uptakes by 51% and 87%, respectively. Thus, the present data show that RPE cells preferentially take up xanthophylls versus the carotene by a process that appears to be entirely SR-BI-dependent for ZEA and partly so for beta-C. This mechanism may explain, in part, the preferential accumulation of xanthophylls in the macula of the retina.     

Oculocutaneous Albinism Type 1: The Last 100 Years

Research on human albinism has been central to many of the major discoveries in human genetics. These include the first evidence that Mendel's rules of genetic segregation apply to humans, first published in 1903. Contrary to initial thought that albinism is caused by mutations in a single gene, we now know that the genetics of albinism are complex. The complexity of albinism was hinted at, in early publications, but has only recently been fully appreciated with the advent of molecular techniques. Currently, 12 different genes have been identified, that when mutated, result in a different type of albinism. Oculocutaneous albinism type 1 (OCA1), resulting from mutations of the tyrosinase gene, is genetically and biochemically the best understood type of albinism. Though much of the research in albinism has involved OCA1, there are many unanswered questions about OCA1 and albinism, in general. The next 100 yr should still provide many surprises as did the first 100 yr.