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  1. Syamila N, Syahir A, Sulaiman Y, Ikeno S, Tan WS, Ahmad H, et al.
    Bioelectrochemistry, 2022 Feb;143:107952.
    PMID: 34600402 DOI: 10.1016/j.bioelechem.2021.107952
    The diagnosis of hepatitis B virus (HBV) and monitoring of the vaccination efficiency against HBV require real-time analysis. The presence of antibody against hepatitis B virus surface antigen (anti-HBsAg) as a result of HBV infection and/or immunization may indicate individual immune status towards HBV. This study investigated the ability of a bio-nanogate-based displacement immunosensing strategy in detecting anti-HBsAg antibody, via nonspecific-binding between polyamidoamine dendrimers encapsulated gold nanoparticles (PAMAM-Au) and the 'antigenic determinant' region (aD) of HBsAg. For this purpose, maltose binding protein harbouring the aD region (MBP-aD) was synthesized as a bioreceptor and immobilized on the screen-printed carbon electrode (SPCE). Following that, PAMAM-Au was deposited on MBP-aD, forming the 'gate' and was used as a monitoring agent. Under optimal conditions, the high specificity of anti-HBsAg antibody towards MBP-aD displaced PAMAM-Au causing the decrement of anodic peak in differential pulse voltammetry (DPV) analysis. The signal changes were proportionally related to the concentration of anti-HBsAg antibody, in a range of 1 - 1000 mIU/mL with a limit of detection (LOD) of 2.5 mIU/mL. The results also showed high specificity and selectivity of the immunosensor platform in detecting anti-HBsAg antibody both in spiked buffer and human serum samples.
  2. Md Hussin NS, Karuppannan M, Gopalan Y, Tan KM, Gnanasan S
    Singapore Med J, 2023 Aug;64(8):497-502.
    PMID: 34600449 DOI: 10.11622/smedj.2021125
    INTRODUCTION: Behavioural and psychological symptoms of dementia (BPSD) are considered integral parts of dementia. While pharmacotherapy is reserved for severe symptoms of BPSD, the associated adverse effects can be detrimental. Therefore, non-pharmacological intervention is recommended as the first line of treatment in the management of BPSD. This study aimed to explore the non-pharmacological approaches for the management of BPSD and the strategies and barriers to implementing them in secondary care facilities in Malaysia.

    METHODS: A qualitative study design was employed. Data were collected through observations and semi-structured interviews of 12 caregivers and 11 people with dementia (PWD) at seven secondary care facilities. Observations were written in the field notes, and interviews were audio-recorded and transcribed. All data were subjected to thematic analysis.

    RESULTS: Some personalised non-pharmacological interventions, such as physical exercise, music therapy, reminiscence therapy and pet therapy, were conducted in several nursing care centres. Collaborative care from the care providers and family members was found to be an important facilitating factor. The lack of family support led to care providers carrying additional workload beyond their job scope. Other barriers to non-pharmacological interventions were cultural and language differences between the care providers and PWD, inadequate staff numbers and training, and time constraints.

    CONCLUSION: Although non-pharmacological approaches have been used to some extent in Malaysia, continuous education and training of healthcare providers and the family members of PWD is needed to overcome the challenges to their successful implementation.

  3. Xu XJ, Myint PK, Kioh SH, Mat S, Rajasuriar R, Kamaruzzaman SB, et al.
    Arch Gerontol Geriatr, 2021 09 30;98:104535.
    PMID: 34601313 DOI: 10.1016/j.archger.2021.104535
    BACKGROUND: While anticholinergic use is associated with stroke, dementia and mortality, few have evaluated its potential link with falls. To determine the relationship between anticholinergic cognitive burden (ACB) and falls over five years using the Malaysian Elders Longitudinal Research (MELoR).

    METHODS: Community-dwelling adults aged 55 years and over were recruited through electoral roll sampling. Data obtained at baseline and follow-up (FU) at two and five years were included. Falls in the preceding 12 months were recorded.

    RESULTS: Of the 1499 individuals (mean (SD) age= 68.9(7.5) yrs and 53.3% female) with information on baseline ACB exposure, 575(38.4%) had ACB scores of 1-2 and 117(7.8%) had ACB scores ≥3. Differences in age, ethnicity, smoking status, diabetes, hypertension, cardiovascular disease, arthritis and education existed between ACB groups. Fall occurrence differed between ACB groups at recruitment (p = 0.004) and 2-year FU (p = 0.001) but not at 5-year FU (p = 0.053). Logistic regression revealed an independent association between ACB 1-2 and falls at baseline (odds ratio, OR (95% confidence interval, CI) =1.412(1.035-1.926)) and ACB≥3 and falls at 2-yr FU (OR (95%CI) =2.098(1.032-4.263)) following adjustment for confounders.

    CONCLUSION: Low level exposure to drugs with anticholinergic properties was associated cross-sectionally with falls, while exposure to higher levels were prospectively associated with falls at 2-year but not at 5-year FU. Future studies should determine whether avoidance of drugs with anticholinergic effects will lead to reduction in falls.

  4. Tong KTX, Tan IS, Foo HCY, Tiong ACY, Lam MK, Lee KT
    Bioresour Technol, 2021 Dec;342:125880.
    PMID: 34592620 DOI: 10.1016/j.biortech.2021.125880
    The development of an efficient third-generation L-lactic acid (L-LA) production process from Eucheuma denticulatum extract (EDE) was achieved in this study. Microwave-assisted dilute acid hydrolysis (MADAH) and microwave-assisted hydrothermal hydrolysis (MAHTH) were chosen as the hydrolysis of EDE for the objective of increasing galactose yield. Single-factor optimization of hydrolysis of the EDE was studied, MADAH had high performance in galactose production relative to MAHTH, in which the yield and optimal conditions for both processes were 50.7% (0.1 M H2SO4, 120 °C for 25 min) and 47.8% (0 M H2SO4,160 °C for 35 min), respectively. For fermentation, the optimal L-LA yield was achieved at the inoculum cell density of 4% (w/w) Bacillus coagulans ATCC 7050 with 89.4% and 6% (w/w) Lactobacillus acidophilus LA-14 with 87.6%. In addition, lipid-extracted Chlorella vulgaris residues (CVRs) as co-nutrient supplementation increased the relative abundance of B. coagulans ATCC 7050, thus benefiting L-LA production.
  5. Krishnan PB, Abdullah M, Hudu SA, Sekawi Z, Tan SS, Amin-Nordin S
    Trop Biomed, 2019 Sep 01;36(3):703-708.
    PMID: 33597492
    Asian countries account for almost three quarter of hepatocellular carcinoma (HCC) reported globally and chronic hepatitis B infection is one of the main contributors. Clinical observations show that Malay patients with chronic hepatitis B and HCC tend to have a worse outcome, when compared to other two major races in Malaysia. The objectives of this study was to determine the frequency of human leukocyte antigen (HLA) class II alleles in chronic hepatitis B patients with HCC among Malays compared to the general population to identify potential associations of HLA alleles with this disease. HLA class II typing was performed in chronic hepatitis B patients with hepatocellular carcinoma (n=12) by -polymerase chain reaction, sequence specific primer (PCR-SSP) method. There were higher allelic frequencies of certain HLA-DQB1 and HLA-DRB1 alleles; HLA-DQB1*03 (07) (41.7%), and HLA-DRB1*12 (41.7% vs 28.6%) and compared to controls (41.7% vs 29.7%). However, there was no significant statistical correlation found when compared with the normal healthy general population. This study provides an insight into the HLA Class II association with chronic hepatitis B and hepatocellular carcinoma in Malays. However, findings from this study should be validated with a larger number of samples using a high resolution HLA typing.
  6. Chemoh W, Nur Farhana MN, Noor Azmi MA, Si Lay K, Sawangjaroen N, Tan TC, et al.
    Trop Biomed, 2019 Sep 01;36(3):694-702.
    PMID: 33597491
    Toxoplasma gondii is a protozoan parasite that is capable of causing a zoonotic disease, known as toxoplasmosis. Vertical transmission of T. gondii from the mother to the fetus, during pregnancy may cause severe complications to the developing fetus. This current study aimed to determine the seroprevalence and investigate the associated risk factors of Toxoplasma infection in pregnant women (n=219) visiting the antenatal clinic at UMMC. While the elevated level of anti-Toxoplasma IgG and IgM antibodies indicates the presence of infection, it fails to differentiate between a past and a recent infection. Thus, the study also demonstrates the usefulness of IgG avidity in validating the timing of infection. The serum samples were tested for the presence of anti-Toxoplasma IgG and IgM antibodies by ELISA test, and the seropositive samples for both anti-Toxoplasma IgG and IgM antibodies were further evaluated by IgG avidity. The results showed that the overall prevalence of T. gondii seropositivity was 34.7%. Of these, 30.6% (67/219) were positive for anti-Toxoplasma IgG antibody only, 2.3% (5/219) were positive for anti-Toxoplasma IgM only, and the remaining 1.8% (4/219) was positive for both anti-Toxoplasma IgG and IgM antibodies. All of the pregnant women who were positive for both anti-Toxoplasma IgG and IgM antibody were found to have past infection when evaluated by IgG avidity. In this study, Malay ethnicity and the number of existing previous children were significantly associated with T. gondii seropositivity (p<0.05). Based on these findings, information and education on the transmission and prevention of congenital toxoplasmosis are very crucial as a public health effort towards a healthier society.
  7. Wong LP, Tan SL, Alias H, Sia TE, Saw A
    Omega (Westport), 2023 Nov;88(1):157-170.
    PMID: 34490819 DOI: 10.1177/00302228211043613
    This study assessed death anxiety (Death Anxiety Questionnaire, DAQ) and psychophysical- (psychological and physical) symptom experience following cadaveric dissection among the Silent Mentor Program (SMP) participants before thawing (T1), after the suturing, dressing and coffining session (T2), and one month post-program (T3). There was a significant decline in the total DAQ score comparing T1 and T2 (t = 7.69, p 
  8. Teo CS, Tan PM, Shu CSI, Choo ZX, Te KK
    Integr Med Res, 2021;10:100783.
    PMID: 34642627 DOI: 10.1016/j.imr.2021.100783
    Background: Implementing Chinese medicine (CM) for COVID-19 in Malaysia is challenging for local CM practitioners. The successful experience of CM in China can only be partially adopted in Malaysia due to differences in the national health care system and legislation, geographical health disparities and cultural diversity. Despite all the challenges, Malaysian CM practitioners have managed to thrive and found a Malaysian CM solution amid COVID-19.

    Methods: A literature review was conducted using various databases and gray literature from inception to August 15, 2021, to evaluate the challenges faced by Malaysian CM practitioners and the corresponding strategies in Malaysia's country context during COVID-19.

    Results: A total of 9 challenges and issues faced by Malaysian CM practitioners during COVID-19 were identified. Their corresponding strategies were further categorized into 3 phases, namely, preparation, development and implementation. The strategies were appraised using the SWOT analysis method, and 17 factors were identified. Strength analysis includes personalized CM prescriptions with online consultations in Malaysia. Limited research input for CM in COVID-19 and the inadequate research capacity of local CM institutions are discussed in threat analysis.

    Conclusion: Various approaches have been implemented by Malaysian CM practitioners to provide safe, qualified and effective CM services for COVID-19 at the community level, aiming to reduce the national health care burden. A public-private partnership initiative can bridge the knowledge gap and optimize the role of CM in the health emergency system. This Malaysian CM solution can provide insights to interested countries to capitalize on the potential contribution of Traditional and Complementary Medicine (T&CM) in the era of COVID-19.

  9. Bakibillah ASM, Kamal MAS, Tan CP, Susilawati S, Hayakawa T, Imura JI
    Sensors (Basel), 2021 Sep 30;21(19).
    PMID: 34640852 DOI: 10.3390/s21196533
    Traditional uncoordinated traffic flows in a roundabout can lead to severe traffic congestion, travel delay, and the increased fuel consumption of vehicles. An interesting way to mitigate this would be through cooperative control of connected and automated vehicles (CAVs). In this paper, we propose a novel solution, which is a roundabout control system (RCS), for CAVs to attain smooth and safe traffic flows. The RCS is essentially a bi-level framework, consisting of higher and lower levels of control, where in the higher level, vehicles in the entry lane approaching the roundabout will be made to form clusters based on traffic flow volume, and in the lower level, the vehicles' optimal sequences and roundabout merging times are calculated by solving a combinatorial optimization problem using a receding horizon control (RHC) approach. The proposed RCS aims to minimize the total time taken for all approaching vehicles to enter the roundabout, whilst minimally affecting the movement of circulating vehicles. Our developed strategy ensures fast optimization, and can be implemented in real-time. Using microscopic simulations, we demonstrate the effectiveness of the RCS, and compare it to the current traditional roundabout system (TRS) for various traffic flow scenarios. From the results, we can conclude that the proposed RCS produces significant improvement in traffic flow performance, in particular for the average velocity, average fuel consumption, and average travel time in the roundabout.
  10. Tang HW, Abbasiliasi S, Ng ZJ, Lee YY, Tang TK, Tan JS
    PMID: 34647854 DOI: 10.1080/10826068.2021.1986721
    Enterococcus sp. has been used as starters in food fermentation due to their probiotic and antimicrobial properties in food biopreservation. The antimicrobial properties were mainly contributed by the bacteriocin called enterocin. Hence, the availability of a cost-effective pilot-scale cultivation conditions is a necessity for the production of probiotic bacteria. This study aims to investigate optimization of medium composition using sugarcane molasses as a carbon source using response surface methodology and the potential use of fed-batch cultivation for improvement of the cell viability of Enterococcus faecium CW3801 for the use as a probiotic starter culture. Two feeding strategies (ramp and constant) were applied in fed-batch cultivation for enhancement of the production of E. faecium in a 2-L stirred tank bioreactor using the optimized medium and scaled up to a 15-L bioreactor. Optimized fermentation medium which comprised of 10% (v/v) of molasses and 10 g/L of yeast extract at pH 7 yielded maximum cell viability of 29.4 × 1011 CFU/mL with 3900 AU/mL of bacteriocin-like inhibitory substances (BLIS) activity. In the fed-batch, the cell viability (8.4 × 1013) and dry cell weight (6.34 g/L) reached the highest in optimized medium when the ramp (stepwise) feeding was applied. In scaling up to 15-L bioreactor, the growth of E. faecium was achieved at 2.3 × 1013 CFU/mL with the dry cell weight of 5.28 g/L under the same condition. The BLIS in 15-L bioreactor was 6% higher than the 2-L bioreactor. This study demonstrated that molasses and yeast extract are good feedstock for the growth of E. faecium. The E. faecium, a non-vancomycin resistant enterococcus (VRE) was successfully produced by a fed-batch cultivation approach and scaled up to a 15-L bioreactor using a ramp feeding strategy. Results from this study revealed that the fed-batch cultivation using molasses-based medium has industrial potential for the production of probiotics.
  11. Chew CL, Tan BA, Low JYS, Mohd Hakimi NIN, Kua SF, Lim CM
    Food Sci Nutr, 2021 Oct;9(10):5335-5343.
    PMID: 34646505 DOI: 10.1002/fsn3.2423
    Quality and food safety are of paramount importance to the palm oil industry. In this work, we investigated the practicability of ethylene gas exogenous application on post-harvested oil palm fruit bunches to improve the crude palm oil (CPO) quality. The bunches were first exposed to ethylene gas for 24 hr to induce abscission of palm fruits from bunches. The detached fruits were then subjected to heat treatment, mechanical extraction, clarification and drying to produce CPO. Critical quality parameters of CPO produced, that is free fatty acid, deterioration of the bleachability index and triacylglycerol showed improvement with ethylene gas treatment. Contaminant content that is phosphorus, chloride, iron, and copper also showed a reduction in the CPO derived from ethylene-treated bunches. These findings corresponded with low levels of contaminants such as 3-monochloropropane-1,2-diol esters and glycidyl esters in refined oil. The implementation strategy and practicability of this method is herein proposed and discussed. Ethylene application not only improves the CPO quality, but could potentially enhance the process sustainability of palm oil mills.
  12. Tan MY, Kwong HC, Crouse KA, Ravoof TBSA, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2021 Aug 01;77(Pt 8):839-846.
    PMID: 34422312 DOI: 10.1107/S2056989021007398
    The title zinc bis-(thio-semicarbazone) complex, [Zn(C22H17N4O2S)2], comprises two N,S-donor anions, leading to a distorted tetra-hedral N2S2 donor set. The resultant five-membered chelate rings are nearly planar and form a dihedral angle of 73.28 (3)°. The configurations about the endocyclic- and exocyclic-imine bonds are Z and E, respectively, and that about the ethyl-ene bond is E. The major differences in the conformations of the ligands are seen in the dihedral angles between the chelate ring and nitro-benzene rings [40.48 (6) cf. 13.18 (4)°] and the N-bound phenyl and nitro-benzene ring [43.23 (8) and 22.64 (4)°]. In the crystal, a linear supra-molecular chain along the b-axis direction features amine-N-H⋯O(nitro) hydrogen bonding. The chains assemble along the 21-screw axis through a combination of phenyl-C-H⋯O(nitro) and π(chelate ring)-π(phen-yl) contacts. The double chains are linked into a three-dimensional architecture through phenyl-C-H⋯O(nitro) and nitro-O⋯π(phen-yl) inter-actions.
  13. Tan MY, Kwong HC, Crouse KA, Ravoof TBSA, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2021 Aug 01;77(Pt 8):788-794.
    PMID: 34422302 DOI: 10.1107/S2056989021006666
    The title thio-urea derivative, C17H19N3OS, adopts a U-shaped conformation with the dihedral angle between the terminal aromatic rings being 73.64 (5)°. The major twist in the mol-ecule occurs about the ethane bond with the Ci-Ce-Ce-Cb torsion angle being -78.12 (18)°; i = imine, e = ethane and b = benzene. The configuration about the imine bond is E, the N-bound H atoms lie on opposite sides of the mol-ecule and an intra-molecular amine-N-H⋯N(imine) hydrogen bond is evident. In the mol-ecular packing, hydroxyl-O-H⋯S(thione) and amine-N-H⋯O hydrogen bonding feature within a linear, supra-molecular chain. The chains are connected into a layer in the ab plane by a combination of methyl-ene-C-H⋯S(thione), methyl-ene-C-H⋯O(hydrox-yl), methyl-C-H⋯π(phen-yl) and phenyl-C-H⋯π(hy-droxy-benzene) inter-actions. The layers stack without directional inter-actions between them. The analysis of the calculated Hirshfeld surface highlights the presence of weak methyl-C-H⋯O(hydrox-yl) and H⋯H inter-actions in the inter-layer region. Computational chemistry indicates that dispersion energy is the major contributor to the overall stabilization of the mol-ecular packing.
  14. Ting RS, Aw Yong YY, Tan MM, Yap CK
    Front Psychol, 2021;12:634863.
    PMID: 34421700 DOI: 10.3389/fpsyg.2021.634863
    Many psychological researchers have proven the deteriorating effects of the coronavirus disease 2019 (Covid-19) pandemic on public mental health. In Malaysia, various Covid-19 clusters were associated with religious gatherings. From a cultural psychology perspective, how ethno-religious groups respond to this crisis originating from their unique rationality and ecological systems. Therefore, this study aimed to explore the illness perceptions of major religious groups (Christian, Muslim, and Buddhist) in Malaysia toward the Covid-19 pandemic, their stress levels, and the relationship between illness perception, stress, and forms of religious expression during the lockdown period. Through an online survey method, 608 Malaysian religious believers were included in this mixed-method empirical study, which adapted standardized instruments [Duke University Religion Index (DUREL), Brief Illness Perception Questionnaire (BIPQ), and Perceived Stress Scale (PSS)]. Statistical analysis showed that all three groups reported moderate levels of stress in average without any significant difference after controlling for age. Both internal and external forms of religious expression had a significant negative relationship with stress levels. Personal control, comprehension, and emotions domains of illness perception accounted for a significant variance in the stress level. Furthermore, religious expression significantly moderated the relationship between some illness perception domains and stress. Qualitative coding revealed that most participants perceived human behavior and attitudes, sociopolitical, and sociological factors as causal factors to the current pandemic. These findings confirmed the relationship between religious expression, illness belief, and stress regulation during the pandemic lockdown. Incidental findings of age as a potential protective factor for Malaysian believers warrants further study. In the conclusion, implications for public health policymakers and religious communities on pandemic prevention and well-being promotion were discussed.
  15. Selvaraj BA, Mariatulqabtiah AR, Ho KL, Ng CL, Yong CY, Tan WS
    Int J Mol Sci, 2021 Aug 13;22(16).
    PMID: 34445426 DOI: 10.3390/ijms22168725
    The causative agent of white tail disease (WTD) in the giant freshwater prawn is Macrobrachium rosenbergii nodavirus (MrNV). The recombinant capsid protein (CP) of MrNV was previously expressed in Escherichia coli, and it self-assembled into icosahedral virus-like particles (VLPs) with a diameter of approximately 30 nm. Extensive studies on the MrNV CP VLPs have attracted widespread attention in their potential applications as biological nano-containers for targeted drug delivery and antigen display scaffolds for vaccine developments. Despite their advantageous features, the recombinant MrNV CP VLPs produced in E. coli are seriously affected by protease degradations, which significantly affect the yield and stability of the VLPs. Therefore, the aim of this study is to enhance the stability of MrNV CP by modulating the protease degradation activity. Edman degradation amino acid sequencing revealed that the proteolytic cleavage occurred at arginine 26 of the MrNV CP. The potential proteases responsible for the degradation were predicted in silico using the Peptidecutter, Expasy. To circumvent proteolysis, specific protease inhibitors (PMSF, AEBSF and E-64) were tested to reduce the degradation rates. Modulation of proteolytic activity demonstrated that a cysteine protease was responsible for the MrNV CP degradation. The addition of E-64, a cysteine protease inhibitor, remarkably improved the yield of MrNV CP by 2.3-fold compared to the control. This innovative approach generates an economical method to improve the scalability of MrNV CP VLPs using individual protease inhibitors, enabling the protein to retain their structural integrity and stability for prominent downstream applications including drug delivery and vaccine development.
  16. Tan BK, Chua SS, Chen LC, Chang KM, Balashanker S, Bee PC
    J Oncol Pharm Pract, 2021 Oct;27(7):1644-1656.
    PMID: 33040675 DOI: 10.1177/1078155220964539
    PURPOSE: Chronic myeloid leukaemia (CML) patients on long-term tyrosine kinase inhibitor (TKI) therapy are susceptible to drug-related problems (DRPs). This study aimed to evaluate the acceptability and outcomes of pharmacist-led interventions on DRPs encountered by CML patients.

    METHODS: This study included participants from the intervention arm of a randomised controlled trial which was conducted to evaluate the effects of pharmacist-led interventions on CML patients treated with TKIs. Participants were recruited and followed up in the haematology clinics of two hospitals in Malaysia from March 2017 to January 2019. A pharmacist identified DRPs and helped to resolve them. Patients were followed-up for six months, and their DRPs were assessed based on the Pharmaceutical Care Network Europe Classification for DRP v7.0. The identified DRPs, the pharmacist's interventions, and the acceptance and outcomes of the interventions were recorded. A Poisson multivariable regression model was used to analyse factors associated with the number of identified DRPs per participant.

    RESULTS: A total of 198 DRPs were identified from 65 CML patients. The median number of DRPs per participants was 3 (interquartile range: 2, 4). Most participants (97%) had at least one DRP, which included adverse drug events (45.5%), treatment ineffectiveness (31.5%) and patients' treatment concerns or dissatisfaction (23%). The 228 causes of DRPs identified comprised the following: lack of disease or treatment information, or outcome monitoring (47.8%), inappropriate drug use processes (23.2%), inappropriate patient behaviour (19.9%), suboptimal drug selection (6.1%), suboptimal dose selection (2.6%) and logistic issues in dispensing (0.4%). The number of concomitant medications was significantly associated with the number of DRPs (adjusted Odds Ratio: 1.100; 95% CI: 1.005, 1.205; p = 0.040). Overall, 233 interventions were made. These included providing patient education on disease states or TKI-related side effects (75.1%) and recommending appropriate instructions for taking medications (7.7%). Of the 233 interventions, 94.4% were accepted and 83.7% were implemented by the prescriber or patient. A total of 154 DRPs (77.3%) were resolved.

    CONCLUSIONS: The pharmacist-led interventions among CML patients managed to identify various DRPs, were well accepted by both TKI prescribers and patients, and had a high success rate of resolving the DRPs.

  17. Chew PC, Christianus A, Zudaidy JM, Ina-Salwany MY, Chong CM, Tan SG
    Animals (Basel), 2021 Sep 08;11(9).
    PMID: 34573599 DOI: 10.3390/ani11092633
    In this study, a mixture of Tor tambra and T. tambroides with unknown genetic background were collected from 11 localities in Malaysia for broodstock development and sperm cryo-banking. This study aims to assess the microsatellite (simple sequence repeat, SSR) variation, genetic diversity, genetic differentiation, level of gene flow, population structure, genetic relatedness and their demographic aspects among these Tor populations, in addition to establishing their SSR profile by employing 22 SSR markers via fragment analysis. Total genomic DNA was extracted from 181 samples (91 cryopreserved milt samples and 90 scale samples of live broodfish). Results showed the Tor spp. collection retained their genetic variation but exhibited excessive homozygosity among individuals within population. Moderate genetic differentiation was shown among the populations, with highly significant (p < 0.001) fixation indices (FST, FIS and FIT). A low gene flow over all loci (Nm 1.548) indicates little genetic variation transfer between populations. The genetic structures of all the populations were successfully resolved into four main clusters by an unweighted pair group method with arithmetic mean (UPGMA) dendrogram generated based on Nei's genetic distances. The population structures based on principal coordinates analysis (PCoA) and the Bayesian model also suggested four distinct clusters following geographical regions and eight closely related populations. This study provided a useful baseline reference for better genetic management and utilization of the Tor spp. stocks in their breeding and conservation programmes.
  18. Tiong ACY, Tan IS, Foo HCY, Lam MK, Mahmud HB, Lee KT
    J Colloid Interface Sci, 2022 Feb;607(Pt 2):1131-1141.
    PMID: 34571300 DOI: 10.1016/j.jcis.2021.09.042
    The synthesis of Janus nanosheets using κ-carrageenan (κ-Ca) as a green template endows a greener and more straightforward method compared to traditional approaches of using wax template. We hypothesize that the hydrogen bonding interaction between κ-Ca and graphene oxide (GO) allows partial masking of GO's single facet, paving the way for the asymmetric modification of the exposed surface. GO is first encapsulated within the porous hydrogel matrix formed by κ-Ca to isolate one of the facets. The exposed surface was then selectively hydrophobized to produce an amphiphilic asymmetrically modified graphene oxide (AMGO). The properties of AMGO synthesized under different κ-Ca/GO ratios were studied. The κ-Ca/GO interactions and the properties of GO and AMGO were investigated and characterized. AMGO was successfully produced with a yield of 90.37 % under optimized synthesis conditions. The separation of κ-Ca and AMGO was conducted without organic solvents, and the κ-Ca could be subsequently recovered. Furthermore, the porous hydrogel matrix formed by κ-Ca and GO exhibited excellent shape-retaining properties with high thermal tolerance of up to 50 °C. Given these benefits, this newly developed method endows sustainability and open the possibility of formulating more flexible material synthesis protocols.
  19. Zhang Y, Yu J, Tan L, Wang X, Li R, Kim DY
    J Microbiol, 2021 Nov;59(11):1044-1055.
    PMID: 34570337 DOI: 10.1007/s12275-021-1361-8
    Getah virus (GETV), which was first isolated in Malaysia in 1955, and Sagiyama virus (SAGV), isolated in Japan in 1956, are members of the genus Alphavirus in the family Togaviridae. It is a consensus view that SAGV is a variant of GETV. In the present study, we determined the complete sequences of the prototype GETV MM2021 and SAGV M6-Mag132 genomic RNA extracted from plaque-purified viruses. The MM2021 genome was 11,692 nucleotides (nt) in length in the absence of 3' poly(A) tail, and the length of M6-Mag132 genome was 11,698 nt. Through sequence alignment of MM2021 and M6-Mag132, we located all the amino acid differences between these two strains, which were scattered in all the encoded proteins. Subsequently, we validated the close evolutionary relationship between GETV and SAGV by constructing phylogenetic trees based on either complete genomes or structural genomes. We eventually analyzed the growth kinetics of GETV and SAGV as well as other representative alphaviruses in various mammalian and insect cell lines. It was shown that human-oriented cell lines such as HEK-293T and Hela cells were relatively resistant to GETV and SAGV infection due to absence of proviral factors or species-specific barrier. On the other hand, both GETV and SAGV replicated efficiently in non-human cell lines. Our results provide essential genetic information for future epidemiological surveillance on Alphaviruses and lay the foundation for developing effective interventions against GETV and SAGV.
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