Prevalence of Cataract Surgery and Visual Outcomes in Indian Immigrants in Singapore: The Singapore Indian Eye Study

Objective

To determine the prevalence of cataract surgery and factors associated with post-surgical visual outcomes in migrant Indians living in Singapore.

Research Design and Methods

We conducted a population-based study in 3,400 Indian immigrants residing in Singapore−the Singapore Indian Eye Study (SINDI). All participants underwent comprehensive medical eye examination and a standardized interview. Post-operative visual impairment (VI) was defined as best-corrected or presenting visual acuity (BCVA or PVA) of 20/60 or worse.

Results

The age- and gender-standardized prevalence of cataract surgery was 9.7% (95% confidence interval [CI]: 8.9%, 10.7%) in Singapore resident Indians. Post-operative VI defined by BCVA occurred in 10.9% eyes (87/795). The main causes of post-operative VI were diabetic retinopathy (20.7%), posterior capsular opacification (18.4%), and age-related macular degeneration (12.6%). Undercorrected refractive error doubled the prevalence of post-operative VI when PVA was used.

Conclusions

The rate of cataract surgery is about 10% in Indian residents in Singapore. Socioeconomic variables and migration had no significant impact on the prevalence of cataract surgery. Diabetic retinopathy was a major cause of post-operative VI in migrant Indians living in Singapore. Uncorrected postoperative refractive error remains an efficient way to improve vision.     

Population trends of European common birds are predicted by characteristics of their climatic niche

Temperate species are projected to experience the greatest temperature increases across a range of modelled climate change scenarios, and climate warming has been linked to geographical range and population changes of individual species at such latitudes. However, beyond the multiple modelling approaches, we lack empirical evidence of contemporary climate change impacts on populations in broad taxonomic groups and at continental scales. Identifying reliable predictors of species resilience or susceptibility to climate warming is of critical importance in assessing potential risks to species, ecosystems and ecosystem services. Here we analysed long‐term trends of 110 common breeding birds across Europe (20 countries), to identify climate niche characteristics, adjusted to other environmental and life history traits, that predict large‐scale population changes accounting for phylogenetic relatedness among species. Beyond the now well‐documented decline of farmland specialists, we found that species with the lowest thermal maxima (as the mean spring and summer temperature of the hottest part of the breeding distribution in Europe) showed the sharpest declines between 1980 and 2005. Thermal maximum predicted the recent trends independently of other potential predictors. This study emphasizes the need to account for both land‐use and climate changes to assess the fate of species. Moreover, we highlight that thermal maximum appears as a reliable and simple predictor of the long‐term trends of such endothermic species facing climate change.     

Do mitochondria make nitric oxide? no?

Several papers have claimed that mitochondria contain nitric oxide synthase (NOS) and make nitric oxide (NO*) in amounts sufficient to affect mitochondrial respiration. However, we found that the addition of L-arginine or the NOS inhibitor L-NMMA to intact rat liver mitochondria did not have any effect on the respiratory rate in both State 3 and State 4. We did not detect mitochondrial NO* production by the oxymyoglobin oxidation assay, or electrochemically using an NO* electrode. An apparent NO* production detected by the Griess assay was identified as an artifact. NO* generated by eNOS added to the mitochondria could easily be detected, although succinate-supplemented mitochondria appeared to consume NO*. Our data show that NO* production by normal rat liver mitochondria cannot be detected in our laboratory, even though the levels of production claimed in the literature should easily have been measured by the techniques used. The implications for the putative mitochondrial NOS are discussed.     

Distribution of plasma alpha-1-B-glycoprotein phenotypes in several Mongoloid populations of East Asia

The distribution of plasma alpha 1B-glycoprotein (alpha 1B) phenotypes was determined by a simple method of two-dimensional electrophoresis followed by protein staining in a group of 1,154 individuals from 8 Mongoloid populations of East Asia. The sample comprised 581 Chinese from different localities (Singapore: 204; Taiwan: 150; Fujien and Hopeh provinces of eastern China: 146 and 81), 155 Koreans, 155 Filipinos, 152 Thais and 111 Malays. Altogether, 6 different alpha 1B phenotypes (1-1, 1-2, 2-2, 1-3, 2-3, and 1-6) were observed. The alpha 1B allele frequencies were very similar in all of the populations. The frequency of A1B*1 varied from 0.89 to 0.91 and that of A1B*2 from 0.08 to 0.10. The A1B*3 allele, reported previously only in American blacks, was observed with a frequency range of 0.003-0.01 in 3 of the Chinese populations, in Koreans and in Malays. A new alpha 1B allele (A1B*6) was observed in 2 Chinese individuals.     

Characterisation of novel functionality within the Blastocystis tryptophanase gene

In recent years, the human gut microbiome has been recognised to play a pivotal role in the health of the host. Intestinal homeostasis relies on this intricate and complex relationship between the gut microbiota and the human host. While much effort and attention has been placed on the characterization of the organisms that inhabit the gut microbiome, the complex molecular cross-talk between the microbiota could also exert an effect on gastrointestinal conditions. Blastocystis is a single-cell eukaryotic parasite of emerging interest, as its beneficial or pathogenic role in the microbiota has been a subject of contention even to-date. In this study, we assessed the function of the Blastocystis tryptophanase gene (BhTnaA), which was acquired by horizontal gene transfer and likely to be of bacterial origin within Blastocystis. Bioinformatic analysis and phylogenetic reconstruction revealed distinct divergence of BhTnaA versus known bacterial homologs. Despite sharing high homology with the E. coli tryptophanase gene, we show that Blastocystis does not readily convert tryptophan into indole. Instead, BhTnaA preferentially catalyzes the conversion of indole to tryptophan. We also show a direct link between E. coli and Blastocystis tryptophan metabolism: In the presence of E. coli, Blastocystis ST7 is less able to metabolise indole to tryptophan. This study examines the potential for functional variation in horizontally-acquired genes relative to their canonical counterparts, and identifies Blastocystis as a possible producer of tryptophan within the gut.     

Biodegradation of dimethyl phthalate by Sphingomonas sp. isolated from phthalic-acid-degrading aerobic granules

This study isolated nine strains of aerobic phenol-degrading granules. These isolates (I1–I9) were characterized using 16S rRNA gene sequencing, with γ-Proteobacteria as the dominant strains in the aerobic granules. While most strains demonstrated either high phenol-degrading capabilities or auto-aggregation capabilities, three isolates, I2, I6, and I8 showed both features. These findings contradict the previous view that auto-aggregation and phenol degradation are mutually exclusive in aerobic granules. Strains I2 and I8 independently formed single-culture aerobic granules except for I3. Anti-microbial activity test results indicated that strains I2 and I8 inhibited growth of strain I3. However, co-culturing I3 with I2 or I8 helped to form granules.     

Observations of a set of isomeric anti-lactose antibodies directed against a group D streptococcal polysaccharide

Sets of isomeric anti-lactose antibodies with specificity for the lactose units of a cell wall polysaccharide fromStreptococcus faecalis strain N were induced in rabbits immunized with a vaccine of nonviable cells of the organism. Such sets of anti-lactose antibodies were isolated from the serum of immunized animals by affinity chromatography on lactosyl-Sepharose. Gel electrofocusing experiments showed that the preparations consisted of multiprotein components. One preparation of antibodies of 13 isomers was separated into homogeneous components by liquid isoelectrofocusing. The individual isomeric antibodies exhibit specificity for the lactose units of the antigenic polysaccharide, possess isoelectric points in the range of 5.9–8.0, and belong to the IgG class of immunoglobulins, and each member yields one light chain and one heavy chain on dissociation in sodium dodecyl sulfate (SDS) and mercaptoethanol. These results have been interpreted as evidence for the assembly of the chains of isomeric antibodies by a single-chain pairing mechanism.     

Bacillus naphthovorans sp. nov. from oil-contaminated tropical marine sediments and its role in naphthalene biodegradation

. A Bacillus sp., designated as strain MN-003, was isolated as the dominant cultivatable naphthalene-degrading organism from oil-contaminated tropical marine sediments. Strain MN-003 is strictly aerobic, rod-shaped, Gram-positive, catalase positive, oxidase negative, and forms endospores. Strain MN-003 grew at salinities ranging from 0.28 to 7.00% and temperatures ranging from 15 to 41°C. Phylogenetic analyses reveal that strain MN-003 is most similar to Bacillus sp. VAN14, with a 16S rRNA sequence identity of 97.9%. Based on taxonomic and 16S rRNA data, strain MN-003 was named Bacillus naphthovorans sp. nov. When grown with naphthalene as sole carbon source, strain MN-003 had a maximal specific growth rate (µmax) of 0.32ǂ.03 h^–1, and a half-saturation constant (Ks) of 22.3dž.2 µM. A batch study of the tropical marine sediments enriched with naphthalene showed that cells of the Bacillus genus grew to become dominant members of the microbial community. The bacilli comprised 39.5Lj.5% of the microbial fraction after 20 days of enrichment.     

Conservation of the Native Orchids Through Seedling Culture and Reintroduction—A Singapore Experience

Singapore is located near the equator, off the southern tip of the Malay Peninsula. The whole country consists mostly of lowland. It has many interesting types of natural habitats such as primary rain forest, freshwater swamp forest, mangroves, secondary forests, shrub, grasslands, and urban parks and fields. The climate is equatorial with relatively uniform temperature and high humidity. Unfortunately, many of the natural habitats and the native orchids which thrive there have disappeared due to habitat destruction. Some 226 species of native orchids have been recorded in Singapore. However, of these 178 are considered to be extinct, and only five are common. The orchid conservation programme aims to monitor existing species, explore ways to conserve their germplasm, and increase their numbers in natural, semi-natural, and urban environments through ex-situ seedling culture and subsequent re-introduction into appropriate habitats, including roadside trees, parks and natural areas. In the first phase of the programme, we have successfully propagated and carried out experiments of re-introduction on five species of native orchids, namely, Grammatophyllum speciosum, Bulbophyllum vaginatum, Bulbophyllum membranaceum, Cymbidium finlaysonianum and Cymbidium bicolor. Survival percentages 8-yr after the reintroduction events ranged from 10 to 95 for G. speciosum, the target species of the earliest re-introduction experiments. Size of the seedlings at reintroduction, host trees, and relative humidity seemed to play significant roles in the success rate of the reintroductions.