14 research outputs found
The Andaman day gecko paradox: an ancient endemic without pronounced phylogeographic structure
The Andaman day gecko (Phelsuma andamanensis) is endemic to the Andaman Archipelago, located ~ 6000 km away from Madagascar where the genus Phelsuma likely evolved. We complemented existing phylogenetic data with additional markers to show that this species consistently branches off early in the evolution of the genus Phelsuma, and this early origin led us to hypothesize that island populations within the Andaman Archipelago could have further diversified. We sampled the Andaman day gecko from all major islands in the Andamans, developed new microsatellite markers and amplified mitochondrial markers to study population diversification. We detected high allelic diversity in microsatellites, but surprisingly poor geographical structuring. This study demonstrates that the Andaman day gecko has a panmictic population (K = 1), but with weak signals for two clusters that we name ‘North’ (North Andaman, Middle Andaman, Interview, Baratang, Neil, and Long Islands) and ‘South’ (Havelock, South Andaman, Little Andaman Islands). The mitochondrial COI gene uncovered wide haplotype sharing across islands with the presence of several private haplotypes (except for the Little Andaman Island, which only had an exclusive private haplotype) signalling ongoing admixture. This species differs from two other Andaman endemic geckos for which we provide comparative mitochondrial data, where haplotypes show a distinct phylogeographic structure. Testing population history scenarios for the Andaman day gecko using Approximate Bayesian Computation (ABC) supports two possible scenarios but fails to tease apart whether admixture or divergence produced the two weak clusters. Both scenarios agree that admixture and/or divergence prior to the onset of the last glacial maximum shaped the genetic diversity and structure detected in this study. ABC supports population expansion, possibly explained by anthropogenic food subsidies via plantations of cash crops, potentially coupled with human mediated dispersal resulting in the observed panmictic population. The Andaman day gecko may thus be a rare example of an island endemic reptile benefiting from habitat modification and increased movement in its native range
Polymorphisms in ARMS2/HTRA1 and complement genes and age-related macular degeneration in India: findings from the INDEYE study.
PURPOSE: Association between genetic variants in complement factor H (CFH), factor B (CFB), component 2 (C2), and in the ARMS2/HTRA1 region with age-related macular degeneration (AMD) comes mainly from studies of European ancestry and case-control studies of late-stage disease. We investigated associations of both early and late AMD with these variants in a population-based study of people aged 60 years and older in India. METHODS: Fundus images were graded using the Wisconsin Age-Related Maculopathy Grading System and participants assigned to one of four mutually exclusive stages based on the worse affected eye (0 = no AMD, 1-3 = early AMD, 4 = late AMD). Multinomial logistic regression was used to derive risk ratios (RR) accounting for sampling method and adjusting for age, sex, and study center. RESULTS: Of 3569 participants, 53.2% had no signs of amd, 45.6% had features of early amd, and 1.2% had late amd. CFH (RS1061170), C2 (RS547154), OR CFB (RS438999) was not associated with early or late AMD. In the ARMS2 locus, RS10490924 was associated with both early (adjusted RR 1.22, 95% confidence interval [CI]: 1.13-1.33, P < 0.0001) and late AMD (adjusted RR 1.81, 95% CI: 1.15-2.86; P = 0.01); rs2672598 was associated only with early AMD (adjusted RR 1.12, 95% CI: 1.02-1.23; P = 0.02); rs10490923 was not associated with early or late AMD. CONCLUSIONS: Two variants in ARMS2/HTRA1 were associated with increased risk of early AMD, and for one of these, the increased risk was also evident for late AMD. The study provides new insights into the role of these variants in early stages of AMD in India
Modificación enzimática de fosfatidilcolina con n-3 PUFA a partir de ácidos grasos de aceites de gusanos de seda
α-Linolenic acid (ALA) containing phosphatidylcholine (PC) was prepared by an enzymatic method employing natural substrates comprising of egg and eri silkworm oil. Eri silkworm oil extracted from eri pupae was saponified to obtain the fatty acid mixture which was further subjected to urea complexation to obtain an ALA rich fraction with a purity of about 93%. Transesterification of PC with the ALA rich fraction with three immobilized lipases namely Lipozyme TL IM, Lipozyme RM IM and lipase from Candida Antarcticaz showed that only the lipase from Candida antarctica was successful for the incorporation of ALA into egg yolk PC. It was found that ALA was incorporated by up to 27% in the sn-1 position of egg PC and the positional distribution analysis of fatty acids in the modified PC showed that the sn-1 position was found to contain about 59% ALA.El ácido α-linolénico (ALA) contenido en fosfatidilcolina (PC) se preparó mediante un método enzimático empleando sustratos naturales que comprenden huevo y aceite de gusanos de seda. El aceite extraído de las crisálidas de gusanos de seda se saponificó para obtener la mezcla de ácidos grasos que se sometió a complejación con urea para obtener la fracción rica en ALA, con una pureza aproximadamente del 93%. La transesterificación de PC con fracción rica en ALA con tres lipasas inmovilizadas, Lipozyme TL IM, Lipozyme RM IM y lipasa de Candida antárctica, mostró que sólo la lipasa de Candida antarctica tuvo éxito en la incorporación de ALA en PC de yema de huevo. Se encontró que el ALA fue incorporado hasta 27% en la posición sn-1 de PC de huevo y el análisis de la distribución de los ácidos grasos en PC modificado mostró que la posición sn-1 que contenía aproximadamente 59% de ALA
Enzymatic modification of phosphatidylcholine with n-3 PUFA from silkworm oil fatty acids
EPHA2 Polymorphisms and Age-Related Cataract in India
Objective: We investigated whether previously reported single nucleotide polymorphisms (SNPs) of EPHA2 in European studies are associated with cataract in India. Methods: We carried out a population-based genetic association study. We enumerated randomly sampled villages in two areas of north and south India to identify people aged 40 and over. Participants attended a clinical examination including lens photography and provided a blood sample for genotyping. Lens images were graded by the Lens Opacification Classification System (LOCS III). Cataract was defined as a LOCS III grade of nuclear >= 4, cortical >= 3, posterior sub-capsular (PSC) >= 2, or dense opacities or aphakia/pseudophakia in either eye. We genotyped SNPs rs3754334, rs7543472 and rs11260867 on genomic DNA extracted from peripheral blood leukocytes using TaqMan assays in an ABI 7900 real-time PCR. We used logistic regression with robust standard errors to examine the association between cataract and the EPHA2 SNPs, adjusting for age, sex and location. Results: 7418 participants had data on at least one of the SNPs investigated. Genotype frequencies of controls were in Hardy-Weinberg Equilibrium (p > 0.05). There was no association of rs3754334 with cataract or type of cataract. Minor allele homozygous genotypes of rs7543472 and rs11260867 compared to the major homozygote genotype were associated with cortical cataract, Odds ratio (OR) = 1.8, 95% Confidence Interval (CI) (1.1, 3.1) p = 0.03 and 2.9 (1.2, 7.1) p = 0.01 respectively, and with PSC cataract, OR = 1.5 (1.1, 2.2) p = 0.02 and 1.8 (0.9, 3.6) p = 0.07 respectively. There was no consistent association of SNPs with nuclear cataract or a combined variable of any type of cataract including operated cataract. Conclusions: Our results in the Indian population agree with previous studies of the association of EPHA2 variants with cortical cataracts. We report new findings for the association with PSC which is particularly prevalent in Indians
31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two
Background
The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd.
Methods
We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background.
Results
First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001).
Conclusions
In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival
Population structure in the Andaman keelback, Xenochrophis tytleri: geographical distance and oceanic barriers to dispersal influence genetic divergence on the Andaman archipelago
Limited gene flow between populations due to geographic distance, presence of barriers or inherent low dispersal ability leads to the formation of genetically structured populations. Strong population structure indicates lowered levels or absence of gene flow which might lead to inbreeding and loss of genetic capacity to recuperate from anthropogenic stress and natural calamities. Terrestrial reptiles are generally known to have low dispersal abilities and few studies have explored drivers of their population structure on continental islands, where both anthropogenic stress and natural calamities are relatively common. We investigated the population structure and drivers of diversification of the Andaman keelback (Xenochrophis tytleri), an endemic, terrestrial and freshwater snake species in the Andaman archipelago, a continental group of islands in the Bay of Bengal. Data was collected from 86 individuals from seven islands and 78 individuals were sequenced for the gene Nuclear Dehydrogenase subunit 4 to identify the number of populations and distribution of genetic diversity across populations. We found 11 haplotypes on seven islands and observed high genetic differentiation between seven populations defined island-wise (F-ST = 0.82). We further tested the number of populations by incorporating spatial data into Bayesian Clustering Analysis (GENELAND) and identified six populations of the Andaman keelback. We tested for the influence of Isolation-by-distance on these populations. While the overall trend showed a positive correlation between geographic and genetic distance, a correlogram revealed that the positive correlation disappears beyond -20-40 km. We also tested for the presence of geographical barriers to gene flow using Monmonier's algorithm (SPADS), which identified five barriers to dispersal confirming that there are oceanic barriers to dispersal for some island populations of the Andaman keelback. As the Andaman Islands are arranged almost in a straight line from North to South, our data are insufficient to tease apart the roles of geographical distance and barriers to gene flow. We conclude that salt waters between near islands are weak barriers and as the geographical distance between islands increases, so does the strength of the barrier
An unusual case of idiopathic multiple invasive cervical resorption
Invasive cervical resorption is a rare form of root resorption, characterized by destruction of the cervical region of teeth resulting from the action of tooth resorbing cells. Being an asymptomatic condition, it is often discovered on routine radiographic examination. This multifactorial disease process can most commonly occur as a sequel to orthodontic treatment, dental trauma, bleaching procedures, and less commonly, as an outcome of segmental orthognathic surgery, periodontal root planning, tetracycline conditioning of the root canal, bruxism, transplantation of tooth, guided tissue regeneration, cementoenamel disjunction. In the absence of these predisposing factors, it can be labeled as ′idiopathic multiple cervical resorption′. This article describes the case of a medically fit Indian male, who displayed idiopathic invasive cervical resorption in multiple teeth
Associations between cataract and rs7543472.
1<p>defined as any of the following on LOCS III: cortical≥3, PSC≥2, nuclear≥4, dense opacities, operated cataract.</p>2<p>LOCS III: cortical≥3.</p>3<p>LOCS III: posterior subcapsular (PSC)≥2.</p>4<p>LOCS III: nuclear≥4.</p
Distribution of participants by cataract status for those who have at least one of the genotyped SNPs.
1<p>“no cataract” defined as the absence of all of the following on LOCS III: cortical≥3, PSC≥2, nuclear≥4, dense opacities, operated cataract.</p>2<p>defined as any of the following on LOCS III: cortical≥3, PSC≥2, nuclear≥4, dense opacities, operated cataract.</p>3<p>LOCS III: cortical≥3.</p>4<p>LOCS III: posterior subcapsular (PSC)≥2.</p>5<p>LOCS III: nuclear ≥4.</p