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  1. Akansha EO, Bui BV, Ganeshrao SB, Bakthavatchalam P, Gopalakrishnan S, Mattam S, et al.
    Int J Environ Res Public Health, 2022 Oct 09;19(19).
    PMID: 36232222 DOI: 10.3390/ijerph191912922
    Evidence suggests that prolonged blue-light exposure can impact vision; however, less is known about its impact on non-visual higher-order functions in the brain, such as learning and memory. Blue-light-blocking lenses (BBLs) claim to reduce these potential impacts. Hence, we assessed structural and functional hippocampal alterations following blue-light exposure and the protective efficacy of BBLs. Male Wistar rats were divided into (n = 6 in each group) normal control (NC), blue-light exposure (LE), and blue-light with BBLs (Crizal Prevencia, CP and DuraVision Blue, DB) groups. After 28 days of light exposure (12:12 light: dark cycle), rats were trained for the Morris water maze memory retention test, and brain tissues were sectioned for hippocampal neuronal analysis using Golgi and Cresyl violet stains. The memory retention test was significantly delayed (p < 0.05) in LE compared with DB groups on day 1 of training. Comparison of Golgi-stained neurons showed significant structural alterations, particularly in the basal dendrites of hippocampal neurons in the LE group, with BBLs significantly mitigating these structural changes (p < 0.05). Comparison of Cresyl-violet-stained neurons revealed significantly (p < 0.001) increased degenerated hippocampal neurons in LE rats, with fewer degenerated neurons in the CP lens group for CA1 neurons (p < 0.05), and for both CP and DB groups (p < 0.05) for CA3 neurons. Thus, in addition to documented effects on visual centers, high-level blue-light exposure also results in degeneration in hippocampal neurons with associated behavioral deficits. These changes can be partially ameliorated with blue-light-blocking lenses.
  2. Ding Y, Saw WY, Tan LWL, Moong DKN, Nagarajan N, Teo YY, et al.
    Appl Environ Microbiol, 2021 09 28;87(20):e0048821.
    PMID: 34347523 DOI: 10.1128/AEM.00488-21
    Multidrug-resistant (MDR) Escherichia coli strains that carry extended-spectrum β-lactamases (ESBLs) or colistin resistance gene mcr-1 have been identified in the human gut at an increasing incidence worldwide. In this study, we isolated and characterized MDR Enterobacteriaceae from the gut microbiota of healthy Singaporeans and show that the detection rates for ESBL-producing and mcr-positive Enterobacteriaceae are 25.7% (28/109) and 7.3% (8/109), respectively. Whole-genome sequencing analysis of the 37 E. coli isolates assigned them into 25 sequence types and 6 different phylogroups, suggesting that the MDR E. coli gut colonizers are highly diverse. We then analyzed the genetic context of the resistance genes and found that composite transposons played important roles in the cotransfer of blaCTX-M-15/55 and qnrS1, as well as the acquisition of mcr-1. Furthermore, comparative genomic analysis showed that 12 of the 37 MDR E. coli isolates showed high similarity to ESBL-producing E. coli isolates from raw meat products in local markets. By analyzing the core genome single nucleotide polymorphisms (SNPs) shared by these isolates, we identified possible clonal transmission of an MDR E. coli clone between human and raw meat, as well as a group of highly similar IncI2 (Delta) plasmids that might be responsible for the dissemination of mcr-1 in a much wider geographic region. Together, these results suggest that antibiotic resistance may be transmitted between different environmental settings by the expansion of MDR E. coli clones, as well as by the dissemination of resistance plasmids. IMPORTANCE The human gut can harbor both antibiotic-resistant and virulent Escherichia coli which may subsequently cause infections. In this study, we found that multidrug-resistant (MDR) E. coli isolates from the gut of healthy Singaporeans carry a diverse range of antibiotic resistance mechanisms and virulence factor genes and are highly diverse. By comparing their genomes with the extended-spectrum β-lactamase (ESBL)-producing E. coli isolates from raw meat products that were sampled at a similar time from local markets, we detected an MDR E. coli clone that was possibly transmitted between humans and raw meat products. Furthermore, we also found that a group of resistance plasmids might be responsible for the dissemination of colistin resistance gene mcr-1 in Singapore, Malaysia, and Europe. Our findings call for better countermeasures to block the transmission of antibiotic resistance.
  3. Teh BT, Lim K, Yong CH, Ng CCY, Rao SR, Rajasegaran V, et al.
    Nat Genet, 2017 Nov;49(11):1633-1641.
    PMID: 28991254 DOI: 10.1038/ng.3972
    Durian (Durio zibethinus) is a Southeast Asian tropical plant known for its hefty, spine-covered fruit and sulfury and onion-like odor. Here we present a draft genome assembly of D. zibethinus, representing the third plant genus in the Malvales order and first in the Helicteroideae subfamily to be sequenced. Single-molecule sequencing and chromosome contact maps enabled assembly of the highly heterozygous durian genome at chromosome-scale resolution. Transcriptomic analysis showed upregulation of sulfur-, ethylene-, and lipid-related pathways in durian fruits. We observed paleopolyploidization events shared by durian and cotton and durian-specific gene expansions in MGL (methionine γ-lyase), associated with production of volatile sulfur compounds (VSCs). MGL and the ethylene-related gene ACS (aminocyclopropane-1-carboxylic acid synthase) were upregulated in fruits concomitantly with their downstream metabolites (VSCs and ethylene), suggesting a potential association between ethylene biosynthesis and methionine regeneration via the Yang cycle. The durian genome provides a resource for tropical fruit biology and agronomy.
  4. Mac Aogáin M, Chandrasekaran R, Lim AYH, Low TB, Tan GL, Hassan T, et al.
    Eur Respir J, 2018 07;52(1).
    PMID: 29880655 DOI: 10.1183/13993003.00766-2018
    Understanding the composition and clinical importance of the fungal mycobiome was recently identified as a key topic in a "research priorities" consensus statement for bronchiectasis.Patients were recruited as part of the CAMEB study: an international multicentre cross-sectional Cohort of Asian and Matched European Bronchiectasis patients. The mycobiome was determined in 238 patients by targeted amplicon shotgun sequencing of the 18S-28S rRNA internally transcribed spacer regions ITS1 and ITS2. Specific quantitative PCR for detection of and conidial quantification for a range of airway Aspergillus species was performed. Sputum galactomannan, Aspergillus specific IgE, IgG and TARC (thymus and activation regulated chemokine) levels were measured systemically and associated to clinical outcomes.The bronchiectasis mycobiome is distinct and characterised by specific fungal genera, including Aspergillus, Cryptococcus and ClavisporaAspergillus fumigatus (in Singapore/Kuala Lumpur) and Aspergillus terreus (in Dundee) dominated profiles, the latter associating with exacerbations. High frequencies of Aspergillus-associated disease including sensitisation and allergic bronchopulmonary aspergillosis were detected. Each revealed distinct mycobiome profiles, and associated with more severe disease, poorer pulmonary function and increased exacerbations.The pulmonary mycobiome is of clinical relevance in bronchiectasis. Screening for Aspergillus-associated disease should be considered even in apparently stable patients.
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