MyMedR

Displaying publications 1 - 20 of 80 in total

Abstract:

Sort:

Ultrasonic assisted ultrafiltration process for emulsification of oil field produced water treatment

Agi A, Junin R, Alqatta AYM, Gbadamosi A, Yahya A, Abbas A

Ultrason Sonochem, 2019 Mar;51:214-222.
PMID: 30401623 DOI: 10.1016/j.ultsonch.2018.10.023

Ultrafiltration has been proven to be very effective in the treatment of oil-in-water emulsions, since no chemical additives are required. However, ultrafiltration has its limitations, the main limits are concentration polarization resulting to permeate flux decline with time. Adsorption, accumulation of oil and particles on the membrane surface which causes fouling of the membrane. Studies have shown that the ultrasonic is effective in cleaning of fouled membrane and enhancing membrane filtration performance. But the effectiveness also, depends on the selection of appropriate membrane material, membrane geometry, ultrasonic module design, operational and processing condition. In this study, a hollow and flat-sheet polyurethane (PU) membranes synthesized with different additives and solvent were used and their performance evaluated with oil-in-water emulsion. The steady-state permeate flux and the rejection of oil in percentage (%) at two different modes were determined. A dry/wet spinning technique was used to fabricate the flat-sheet and hollow fibre membrane (HFMs) using Polyethersulfone (PES) polymer base, Polyvinylpyrrolidone (PVP) additive and N, N-Dimethylacetamide (DMAc) solvent. Ultrasonic assisted cross-flow ultrafiltration module was built to avoid loss of ultrasonic to the surrounding. The polyurethane (PU) was synthesized by polymerization and sulphonation to have an anionic group (-OH; -COOH; and -SO3H) on the membrane surface. Changes in morphological properties of the membrane had a significant effect on the permeate flow rate and oil removal. Generation of cavitation and Brownian motion by the ultrasonic were the dominant mechanisms responsible for ultrafiltration by cracking the cake layers and reducing concentration polarization at the membrane surface. The percentage of oil after ultrafiltration process with ultrasonic is about 90% compared to 49% without ultrasonic. Ultrasonic is effective in enhancing the membrane permeate flux and controlling membrane fouling.
Microbial community dynamics and functional potentials in the conversion of oil palm wastes into biomethane

Ng HJ, Goh KM, Yahya A, Abdul-Wahab MF

3 Biotech, 2024 Mar;14(3):91.
PMID: 38419684 DOI: 10.1007/s13205-024-03933-8

Oil palm processing generates substantial waste materials rich in organic content, posing various environmental challenges. Anaerobic digestion (AD), particularly for palm oil mill effluent (POME), offers a sustainable solution, by converting waste into valuable biomethane for thermal energy or electricity generation. The synergistic activities of the AD microbiota directly affect the biomethane production, and the microbial community involved in biomethane production in POME anaerobic digestion has been reported. The composition of bacterial and archaeal communities varies under different substrate and physicochemical conditions. This review discusses the characteristics of POME, explores the microbial members engaged in each stage of AD, and elucidates the impacts of substrate and physicochemical conditions on the microbial community dynamics, with a specific focus on POME. Finally, the review outlines current research needs and provides future perspectives on optimizing the microbial communities for enhanced biomethane production from oil palm wastes.
Sociobiological risk factors for spontaneous abortion in Malaysia

Tan NH, Yahya A, Adeeb N

J Obstet Gynaecol (Tokyo 1995), 1995 Aug;21(4):313-8.
PMID: 8775898

OBJECTIVE: To evaluate the risk factors of spontaneous abortion.
METHODS: A case-control study was conducted by interviewing 350 women who were admitted to the university gynaecological unit for spontaneous abortion and 350 women who delivered normally at the university obstetric unit. Odds ratios, as the estimators of relative risks, were calculated.
RESULTS: The relative risk for spontaneous abortion among women in the age-group 30 to 39 years was 1.61 and among women above 40 years of age was 3.68 when compared to those below 30 years of age. In relation to career women, the relative risk of spontaneous abortion for housewives was 0.45. Ethnic group, parity, subfertility, previous induced abortion, ectopic pregnancy, contraception and menarcheal age did not influence the risk of spontaneous abortion.
CONCLUSION: Increasing age and a woman's career are significant risk factors of spontaneous abortion.
Fulltext Coverage extension and balancing the transmitted power of the moving relay node at LTE-A cellular network

Aldhaibani JA, Yahya A, Ahmad RB

ScientificWorldJournal, 2014;2014:815720.
PMID: 24672378 DOI: 10.1155/2014/815720

The poor capacity at cell boundaries is not enough to meet the growing demand and stringent design which required high capacity and throughput irrespective of user's location in the cellular network. In this paper, we propose new schemes for an optimum fixed relay node (RN) placement in LTE-A cellular network to enhance throughput and coverage extension at cell edge region. The proposed approach mitigates interferences between all nodes and ensures optimum utilization with the optimization of transmitted power. Moreover, we proposed a new algorithm to balance the transmitted power of moving relay node (MR) over cell size and providing required SNR and throughput at the users inside vehicle along with reducing the transmitted power consumption by MR. The numerical analysis along with the simulation results indicates that an improvement in capacity for users is 40% increment at downlink transmission from cell capacity. Furthermore, the results revealed that there is saving nearly 75% from transmitted power in MR after using proposed balancing algorithm. ATDI simulator was used to verify the numerical results, which deals with real digital cartographic and standard formats for terrain.
Fulltext Effects of saline irrigation water on morphological characteristics of banana (Musa spp.)

Al Harthy, K. M., Siti Aishah, H., Yahya, A., Roslan, I., Al Yahyai, R.

International Food Research Journal, 2018;25(102):195-200.
MyJurnal

Banana is one of the most important food crops after rice, wheat and corn around the world. It is susceptible to a wide spectrum of non-infectious problems such as abiotic stresses resulting in restricting growth and production. Studies were conducted to determine the effects of four salinity levels (0.17 (control), 3.0, 6.0, and 9.0 dS m-1) on morphological characteristics of four banana cultivars at vegetative growth stage. Banana cultivars from the Cavendish group (Williams, Malindi) and plantains group (FHIA18 and Diwan) were grown in 61 x 76 cm polyethylene bags filled with soil mixture comprising of top soil, sand and peat moss (3:1:2 v/v), with pH ranging from 6 - 6.5 and EC 0.02 mScm-1. The experiment was carried out under a rain-shelter in split-plot design with three replicates. Plants were irrigated manually. Data were collected at 3, 6 and 9 months after transplanting. The results revealed that, the number of leaves, stem height, stem girth and total leaf area were significantly affected by salinity, variety and plant age. Significant interaction was also found between salinity and variety, salinity and plant age, as well as variety and plant age. The morphological characteristics of banana were negatively affected by higher salinity levels (6.0 and 9.0 dS m-1). Under similar salinity level, cultivar Malindi had higher number of leaves, stem height, stem girth and total leaf area as compared to cultivar Williams. Among plantains banana, cultivar FHIA18 was more tolerance to high salinity levels than Diwan cultivar, while Malindi from Cavendish group shows high salt tolerant than Williams. Therefore cultivars Malindi and FHIA18 could be grown in arid and semiarid environment depend on their tolerance to high salinity level above 1.0 dS m-1.
Silica exposure is associated with an increased risk of developing ACPA-positive rheumatoid arthritis in an Asian population: evidence from the Malaysian MyEIRA case-control study

Yahya A, Bengtsson C, Larsson P, Too CL, Mustafa AN, Abdullah NA, et al.

Mod Rheumatol, 2014 Mar;24(2):271-4.
PMID: 24593203 DOI: 10.3109/14397595.2013.854076

OBJECTIVES: Silica exposure has been associated with an increased risk of developing rheumatoid arthritis (RA), especially among smokers. In this study, we aimed at examining the association between silica exposure (and its interaction with smoking) and the risk of RA in the Malaysian population.
METHODS: In total, 149 cases and 213 matched controls, all men, were included between August 2005 and December 2009. A case was defined as a person with early diagnosed RA using the 1987 American College of Rheumatology criteria for RA. Controls were randomly selected matched on sex, age and residential area. Silica exposure was defined as exposure to stone dust, rock drilling or stone crushing, and smoking status was categorized as ever/never cigarette smoking.
RESULTS: An increased risk of anti-citrullinated protein antibody (ACPA)-positive RA (OR = 2.4, 95 % CI 1.0-5.6) was observed among those exposed to silica. Ever-smokers exposed to silica had a particularly high risk of developing ACPA-positive RA (OR = 7.5, 95 % CI 2.3-24.2), compared with never-smokers not exposed to silica. No association was found regarding ACPA-negative RA.
CONCLUSION: Our data demonstrate that exposure to both silica and cigarette smoke comprise risks for developing RA in the Malaysian genetic context. The findings expand a link between environmental lung exposures and ACPA-positive RA to Asian populations.
Silica exposure is associated with an increased risk of developing ACPA-positive rheumatoid arthritis in an Asian population: evidence from the Malaysian MyEIRA case-control study

Yahya A, Bengtsson C, Larsson P, Too CL, Mustafa AN, Abdullah NA, et al.

Mod Rheumatol, 2013 Apr 25.
PMID: 23615838

OBJECTIVES: Silica exposure has been associated with an increased risk of developing rheumatoid arthritis (RA), especially among smokers. In this study, we aimed at examining the association between silica exposure (and its interaction with smoking) and the risk of RA in the Malaysian population. METHODS: In total, 149 cases and 213 matched controls, all men, were included between August 2005 and December 2009. A case was defined as a person with early diagnosed RA using the 1987 American College of Rheumatology criteria for RA. Controls were randomly selected matched on sex, age and residential area. Silica exposure was defined as exposure to stone dust, rock drilling or stone crushing, and smoking status was categorized as ever/never cigarette smoking. RESULTS: An increased risk of anti-citrullinated protein antibody (ACPA)-positive RA (OR = 2.4, 95 % CI 1.0-5.6) was observed among those exposed to silica. Ever-smokers exposed to silica had a particularly high risk of developing ACPA-positive RA (OR = 7.5, 95 % CI 2.3-24.2), compared with never-smokers not exposed to silica. No association was found regarding ACPA-negative RA. CONCLUSION: Our data demonstrate that exposure to both silica and cigarette smoke comprise risks for developing RA in the Malaysian genetic context. The findings expand a link between environmental lung exposures and ACPA-positive RA to Asian populations.
Fulltext Pinostrobin attenuates azoxymethane-induced colorectal cytotoxicity in rats through augmentation of apoptotic Bax/Bcl-2 proteins and antioxidants

Ali Abed Wahab B, Ain Salehen N, Abdulla MA, A J Jabbar A, Abdel Aziz Ibrahim I, Almaimani G, et al.

SAGE Open Med, 2023;11:20503121231216585.
PMID: 38078205 DOI: 10.1177/20503121231216585

OBJECTIVES: Pinostrobin (5-hydroxy-7-methoxyflavanone; PN) is a natural active ingredient with numerous biological activities extensively utilized in tumour chemotherapy. The present study investigates the chemo-preventive potentials of PN on azoxymethane-mediated colonic aberrant crypt foci in rats.
METHODS: Sprague Dawley rats clustered into five groups, normal control (A) and cancer controls were subcutaneously injected with normal saline and 15 mg/kg azoxymethane, respectively, and nourished on 10% tween 20 and fed on 10% tween 20; reference control (C), injected with 15 mg/kg azoxymethane and injected (intraperitoneal) with 35 mg/kg 5-fluorouracil (5-FU); D and E rat groups received a subcutaneous injection of 15 mg/kg azoxymethane and nourished on 30 and 60 mg/kg of PN, respectively.
RESULTS: The acute toxicity trial showed a lack of any abnormal signs or mortality in rats ingested with 250 and 500 mg/kg of PN. The gross morphology of colon tissues revealed significantly lower total colonic aberrant crypt foci incidence in PN-treated rats than that of cancer controls. Histological examination of colon tissues showed increased aberrant crypt foci availability with bizarrely elongated nuclei, stratified cells and higher depletion of the submucosal glands in cancer controls. PN treatment caused positive modulation of apoptotic (Bax and Bcl-2) proteins and inflammatory cytokines (TNF-α, IL-6 and IL-10). Moreover, rats fed on PN had significantly higher antioxidants (superoxide dismutase) and lower malondialdehyde concentrations in their colon tissue homogenates.
CONCLUSION: The chemoprotective efficiency of PN against azoxymethane-induced aberrant crypt foci is shown by lower aberrant crypt foci values and higher aberrant crypt foci inhibition percentage, possibly through augmentation of genes responsible for apoptotic cascade and inflammations originating from azoxymethane oxidative stress insults.
Boric Acid (Boron) Attenuates AOM-Induced Colorectal Cancer in Rats by Augmentation of Apoptotic and Antioxidant Mechanisms

Jabbar AAJ, Alamri ZZ, Abdulla MA, Salehen NA, Ibrahim IAA, Hassan RR, et al.

Biol Trace Elem Res, 2024 Jun;202(6):2702-2719.
PMID: 37770673 DOI: 10.1007/s12011-023-03864-0

Boric acid (BA) is a naturally occurring weak Lewis acid containing boron, oxygen, and hydrogen elements that can be found in water, soil, and plants. Because of its numerous biological potentials including anti-proliferation actions, the present investigates the chemopreventive possessions of BA on azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) in rats. Thirty laboratory rats were divided into 5 groups: negative control (A) received two subcutaneous inoculations of normal saline and nourished on 10% Tween 20; groups B-E had two injections of 15 mg/kg azoxymethane followed by ingestion of 10% Tween 20 (B, cancer control), inoculation with intraperitoneal 35 mg/kg 5-fluorouracil injection (C, reference group), or ingested with boric acid 30 mg/kg (D) and 60 mg/kg (E). The gross morphology results showed significantly increased total colonic ACF in cancer controls, while BA treatment caused a significant reduction of ACF values. Histopathological evaluation of colons from cancer controls showed bizarrely elongated nuclei, stratified cells, and higher depletion of the submucosal glands than that of BA-treated groups. Boric acid treatment up-surged the pro-apoptotic (Bax) expression and reduced anti-apoptotic (Bcl-2) protein expressions. Moreover, BA ingestion caused upregulation of antioxidant enzymes (GPx, SOD, CAT), and lowered MDA contents in colon tissue homogenates. Boric acid-treated rats had significantly lower pro-inflammatory cytokines (TNF-α and IL-6) and higher anti-inflammatory cytokines (IL-10) based on serum analysis. The colorectal cancer attenuation by BA is shown by the reduced ACF numbers, anticipated by its regulatory potentials on the apoptotic proteins, antioxidants, and inflammatory cytokines originating from AOM-induced oxidative damage.
Sterilizing orthodontic appliances: A systematic review and meta-analysis on the available methods

Abutayyem H, Alam MK, Kanwal B, Alswairki HJ, Alogaibi YA

J Orthod Sci, 2023;12:51.
PMID: 37881658 DOI: 10.4103/jos.jos_53_23

Infection control is essential to protect both the doctor and the patient by preventing the spread of infectious diseases. There is no exception in the field of dentistry, particularly in orthodontics, where numerous appliances are used for a variety of functions and also because the mouth cavity has the highest concentration of bacteria of any body part. Through this systematic review, we aimed to assess the various methods of sterilization employed in an orthodontic setting. Using relevant keywords, reference searches, and citation searches, the databases such as PubMed, MEDLINE, Web of Science, Cochrane, and Scopus were all searched; a total of 206 documents were found, of which 113 were initially selected. The remaining 23 distinct papers were initially made available after 90 publications that were identical to or similar to one another were eliminated. The final selection was made from eight documents that met all inclusion and exclusion requirements. The existing methods of sterilization were found to be competent in dealing with the microorganisms found in a typical orthodontic setting. The chemical method of sterilization was the norm in most of the studies that we assessed, with glutaraldehyde and peracetic acid (PAA) being the most commonly employed compounds for disinfection. PROSPERO Registration Number: CRD42022380831.
Fulltext A dataset representing the identification of three microalgae species isolated from freshwater areas at Glami Lemi River, Malaysia

Hanan MY, Yahya A, Jaafar MZ, Amatul-Samahah MA

Data Brief, 2022 Dec;45:108761.
PMID: 36471664 DOI: 10.1016/j.dib.2022.108761

Microalgae play an important function in aquatic environments by serving as the energy foundation of the food chain for all aquatic species. Microalgae produce a wide range of bioproducts, including polysaccharides, lipids, pigments, proteins, vitamins, bioactive chemicals, and antioxidants. In this study, a dataset of identification of three microalgae isolated from freshwater riverine areas at Glami Lemi River, Malaysia is presented. The identification data was acquired using molecular identification using the PCR method and morphological observation. The morphological observation of the microalgae isolates, GL01, GL02, and GL03, showed the closest features and characteristics with Chlorella sp., Ankinstrodesmus sp., and Tetradesmus (Scenedesmus) sp., respectively. The sequence similarity analysis of partial 18s rDNA gene using BLASTn identified the three microalgae species as Chlorella sorokiniana for isolate GL01, Ankistrodesmus fusiformis for isolate GL02, and Tetradesmus obliquus for isolate GL03. Both morphological observation and molecular identification were in agreement in the determination of the species. This is the first report on the three microalgae species isolated from this area.
Influence of Feeding and Controlled Dissolved Oxygen Level on the Production of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) Copolymer by Cupriavidus sp. USMAA2-4 and Its Characterization

Shantini K, Yahya AR, Amirul AA

Appl Biochem Biotechnol, 2015 Jul;176(5):1315-34.
PMID: 25951779 DOI: 10.1007/s12010-015-1648-5

Copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] has been the center of attention in the bio-industrial fields, as it possesses superior mechanical properties compared to poly(3-hydroxybutyrate) [P(3HB)]. The usage of oleic acid and 1-pentanol was exploited as the carbon source for the production of P(3HB-co-3HV) copolymer by using a locally isolated strain Cupriavidus sp. USMAA2-4. In this study, the productivity of polyhydroxyalkanoate (PHA) was improved by varying the frequency of feeding in fed-batch culture. The highest productivity (0.48 g/L/h) that represents 200 % increment was obtained by feeding the carbon source and nitrogen source three times and also by considering the oxygen uptake rate (OUR) and oxygen transfer rate (OTR). A significantly higher P(3HB-co-3HV) concentration of 25.7 g/L and PHA content of 66 wt% were obtained. The 3-hydroxyvalerate (3HV) monomer composition obtained was 24 mol% with the growth of 13.3 g/L. The different frequency of feeding carried out has produced a blend copolymer and has broadened the monomer distribution. In addition, increase in number of granules was also observed as the frequency of feeding increases. In general, the most glaring increment in productivity offer advantage for industrial P(3HB-co-3HV) production, and it is crucial in developing cost-effective processes for commercialization.
Fulltext Correlation analysis of air pollutant index levels and dengue cases across five different zones in Selangor, Malaysia

Thiruchelvam L, Dass SC, Zaki R, Yahya A, Asirvadam VS

Geospat Health, 2018 05 07;13(1):613.
PMID: 29772882 DOI: 10.4081/gh.2018.613

This study investigated the potential relationship between dengue cases and air quality - as measured by the Air Pollution Index (API) for five zones in the state of Selangor, Malaysia. Dengue case patterns can be learned using prediction models based on feedback (lagged terms). However, the question whether air quality affects dengue cases is still not thoroughly investigated based on such feedback models. This work developed dengue prediction models using the autoregressive integrated moving average (ARIMA) and ARIMA with an exogeneous variable (ARIMAX) time series methodologies with API as the exogeneous variable. The Box Jenkins approach based on maximum likelihood was used for analysis as it gives effective model estimates and prediction. Three stages of model comparison were carried out for each zone: first with ARIMA models without API, then ARIMAX models with API data from the API station for that zone and finally, ARIMAX models with API data from the zone and spatially neighbouring zones. Bayesian Information Criterion (BIC) gives goodness-of-fit versus parsimony comparisons between all elicited models. Our study found that ARIMA models, with the lowest BIC value, outperformed the rest in all five zones. The BIC values for the zone of Kuala Selangor were -800.66, -796.22, and -790.5229, respectively, for ARIMA only, ARIMAX with single API component and ARIMAX with API components from its zone and spatially neighbouring zones. Therefore, we concluded that API levels, either temporally for each zone or spatio- temporally based on neighbouring zones, do not have a significant effect on dengue cases.
Fulltext Evaluation of awareness & utilisation of clinical practise guideline for management of adult dengue infection among Malaysia doctors

Ariff MI, Yahya A, Zaki R, Sarimin R, Mohamed Ghazali IM, Gill BS, et al.

PLoS One, 2017;12(5):e0178137.
PMID: 28562626 DOI: 10.1371/journal.pone.0178137

Clinical Practice Guideline (CPG) provides evidence-based guidance for the management of Dengue Infection in adult patients. A cross sectional study was conducted to evaluate awareness and utilization of CPG among doctors in public or private hospitals and clinics in Malaysia. Doctors practicing only at hospital Medical and Emergency Departments were included, while private specialist clinics were excluded in this study. A multistage proportionate random sampling according to region (Central, Northern, Southern, Eastern, Sabah and Sarawak) was performed to select study participants. The overall response rate was 74% (84% for public hospitals, 82% for private hospitals, 70% for public clinics, and 64% for private clinics). The CPG Awareness and Utilization Feedback Form were used to determine the percentage in the study. The total numbers of respondent were 634 with response rate of 74%. The mean lengths of service of the respondent were 13.98 (11.55).A higher percentages of doctors from public facilities (99%) were aware of the CPG compared to those in private facilities (84%). The percentage of doctors utilising the CPG were also higher (98%) in public facilities compared to private facilities (86%). The percentage of Medical Officer in private facilities that utilizing the CPG were 84% compares to Medical Officer in public facilities 98%. The high percentage of doctors using the CPG in both public (97%) and private (94%) hospitals were also observed. However, only 69% of doctors in private clinics utilised the CPG compared to doctors in public clinics (98%). Doctors in both public and private facilities were aware of the dengue CPG. However, most doctors in private clinic were less likely to utilise the CPG. Therefore, there is a need to increase the level of CPG utilisation especially in private clinics.
Study site: primary care and hospital from Medical and Emergency Department, public and private health facilities in Malaysia
Sarcopenia and All-Cause Mortality Risk in Community-Dwelling Rural Malaysian Older Adults

Ramoo K, Hairi NN, Yahya A, Choo WY, Hairi FM, Ismail N, et al.

Asia Pac J Public Health, 2024 Mar;36(2-3):225-231.
PMID: 38482589 DOI: 10.1177/10105395241237811

Sarcopenia is associated with numerous adverse health outcomes, including frailty, disability, and mortality. Since the Asian Working Group for Sarcopenia 2019 guidelines, which were published in 2020, are relatively new, studies on the association between sarcopenia as defined by these guidelines and mortality are limited in the Asian region. Accordingly, this study aimed to examine the all-cause mortality risk associated with sarcopenia among community-dwelling older adults in rural Malaysia. This cohort study included 2404 older adults residing in Kuala Pilah District, Negeri Sembilan, Malaysia who were followed up for 83 months. The prevalence rates of sarcopenia and severe sarcopenia were 5.0% and 3.60%, respectively. Older adults with sarcopenia and severe sarcopenia had a 114% (hazard ratio [HR]: 2.14) and 146% (HR: 2.46) increased mortality risk compared with those without sarcopenia (HR: 2.14). Our findings indicate that early intervention is recommended to prevent sarcopenia in older adults.
A review of heart valve disease research in Malaysia

Khoo PLZ, Poon JS, Tan GJS, Yahya A, Chan KMJ

Med J Malaysia, 2020 11;75(6):722-730.
PMID: 33219184

INTRODUCTION: Heart valve disease comprises a cluster of conditions affecting the aortic, mitral, pulmonary and tricuspid valves. This paper reviews all the research on heart valve disease in Malaysia published between the years 2000- 2016.
METHODS: The methodology was based on the search process described in the paper, "Bibliography of clinical research in Malaysia: methods and brief results". The search databases included PubMed, Scopus and several Malaysian journals such as MyJurnal and UKM Journal Repository, by using the following keywords: (heart valve disease OR infective endocarditis OR rheumatic heart disease) and (Malaysia).
RESULTS: In all 94 papers were identified of which 39 papers were selected and reviewed on the basis of their relevance. The local studies contributed to the knowledge and understanding of the epidemiology, aetiology, pathophysiology, clinical presentations, investigations, treatment, and outcomes of heart valve disease in the country.
DISCUSSION: The clinical relevance of the studies performed in the country is discussed along with recommendations for future research.
Draft genome sequence of Parvularcula flava strain NH6-79 T, revealing its role as a cellulolytic enzymes producer

Abdul Karim MH, Lam MQ, Chen SJ, Yahya A, Shahir S, Shamsir MS, et al.

Arch Microbiol, 2020 Nov;202(9):2591-2597.
PMID: 32607725 DOI: 10.1007/s00203-020-01967-z

To date, the genus Parvularcula consists of 6 species and no potential application of this genus was reported. Current study presents the genome sequence of Parvularcula flava strain NH6-79 T and its cellulolytic enzyme analysis. The assembled draft genome of strain NH6-79 T consists of 9 contigs and 7 scaffolds with 3.68 Mbp in size and GC content of 59.87%. From a total of 3,465 genes predicted, 96 of them are annotated as glycoside hydrolases (GHs). Within these GHs, 20 encoded genes are related to cellulosic biomass degradation, including 12 endoglucanases (5 GH10, 4 GH5, and 3 GH51), 2 exoglucanases (GH9) and 6 β-glucosidases (GH3). In addition, highest relative enzyme activities (endoglucanase, exoglucanase, and β-glucosidase) were observed at 27th hour when the strain was cultured in the carboxymethyl cellulose/Avicel®-containing medium for 45 h. The combination of genome analysis with experimental studies indicated the ability of strain NH6-79 T to produce extracellular endoglucanase, exoglucanase, and β-glucosidase. These findings suggest the potential of Parvularcula flava strain NH6-79 T in cellulose-containing biomass degradation and that the strain could be used in cellulosic biorefining process.
Fulltext Robertkochia solimangrovi sp. nov., isolated from mangrove soil, and emended description of the genus Robertkochia

Lam MQ, Vodovnik M, Zorec M, Chen SJ, Goh KM, Yahya A, et al.

Int J Syst Evol Microbiol, 2020 Mar;70(3):1769-1776.
PMID: 31976852 DOI: 10.1099/ijsem.0.003970

To date, there is sparse information for the genus Robertkochia with Robertkochia marina CC-AMO-30DT as the only described member. We report here a new species isolated from mangrove soil collected at Malaysia Tanjung Piai National Park and perform polyphasic characterization to determine its taxonomic position. Strain CL23T is a Gram-negative, yellow-pigmented, strictly aerobic, catalase-positive and oxidase-positive bacterium. The optimal growth conditions were determined to be at pH 7.0, 30-37 °C and in 1-2 % (w/v) NaCl. The major respiratory quinone was menaquinone-6 (MK-6) and the highly abundant polar lipids were four unidentified lipids, a phosphatidylethanolamine and two unidentified aminolipids. The 16S rRNA gene similarity between strain CL23T and R. marina CC-AMO-30DT is 96.67 %. Strain CL23T and R. marina CC-AMO-30DT clustered together and were distinguished from taxa of closely related genera in 16S rRNA gene phylogenetic analysis. Genome sequencing revealed that strain CL23T has a genome size of 4.4 Mbp and a G+C content of 40.72 mol%. Overall genome related indexes including digital DNA-DNA hybridization value and average nucleotide identity are 17.70 % and approximately 70%, below the cutoffs of 70 and 95%, respectively, indicated that strain CL23T is a distinct species from R. marina CC-AMO-30DT. Collectively, based on the phenotypic, chemotaxonomic, phylogenetic and genomic evidences presented here, strain CL23T is proposed to represent a new species with the name Robertkochia solimangrovi sp. nov. (KCTC 72252T=LMG 31418T). An emended description of the genus Robertkochia is also proposed.
Genome analysis of cellulose and hemicellulose degrading Micromonospora sp. CP22

Chen SJ, Lam MQ, Thevarajoo S, Abd Manan F, Yahya A, Chong CS

3 Biotech, 2020 Apr;10(4):160.
PMID: 32206494 DOI: 10.1007/s13205-020-2148-z

In this study, a bacterial strain CP22 with ability to produce cellulase, xylanase and mannanase was isolated from the oil palm compost. Based on the 16S rRNA gene analysis, the strain was affiliated to genus Micromonospora. To further investigate genes that are related to cellulose and hemicellulose degradation, the genome of strain CP22 was sequenced, annotated and analyzed. The de novo assembled genome of strain CP22 featured a size of 5,856,203 bp with G + C content of 70.84%. Detailed genome analysis on lignocellulose degradation revealed a total of 60 genes consisting of 47 glycoside hydrolase domains and 16 carbohydrate esterase domains predicted to be involved in cellulolytic and hemicellulolytic deconstruction. Particularly, 20 genes encode for cellulases (8 endoglucanases, 3 exoglucanases and 9 β-glucosidases) and 40 genes encode for hemicellulases (15 endo-1,4-β-xylanase, 3 β-xylosidase, 3 α-arabinofuranosidase, 10 acetyl xylan esterase, 6 polysaccharide deacetylase, 1 β-mannanase, 1 β-mannosidase and 1 α-galactosidase). Thirty-two genes encoding carbohydrate-binding modules (CBM) from six different families (CBM2, CBM4, CBM6, CBM9, CBM13 and CBM22) were present in the genome of strain CP22. These CBMs were found in 27 cellulolytic and hemicellulolytic genes, indicating their potential role in enhancing the substrate-binding capability of the enzymes. CBM2 and CBM13 are the major CBMs present in cellulases and hemicellulases (xylanases and mannanases), respectively. Moreover, a GH10 xylanase was found to contain 3 CBMs (1 CBM9 and 2 CBM22) and these CBMs were reported to bind specifically to xylan. This genome-based analysis could facilitate the exploration of this strain for lignocellulosic biomass degradation.
Fulltext Genome sequence data of Mangrovimonas sp. strain CR14 isolated from mangrove forest at Tanjung Piai National Park, Malaysia

Zakaria MR, Lam MQ, Chen SJ, Abdul Karim MH, Tokiman L, Yahya A, et al.

Data Brief, 2020 Jun;30:105658.
PMID: 32426431 DOI: 10.1016/j.dib.2020.105658

Mangrovimonas sp. strain CR14 is a halophilic bacterium affiliated with family Flavobacteriaceae which was successfully isolated from mangrove soil samples obtained from Tanjung Piai National Park, Johor. The whole genome of strain CR14 was sequenced on an Illumina HiSeq 2500 platform (2 × 150 bp paired end). Herein, we report the genome sequence of Mangrovimonas sp. strain CR14 in which its assembled genome consisted 20 contigs with a total size of 3,590,195 bp, 3209 coding sequences, and an average 36.08% G + C content. Genome annotation and gene mining revealed that this bacterium demonstrated proteolytic activity which could be potentially applied in detergent industry. This whole-genome shotgun data of Mangrovimonas sp. strain CR14 has been deposited at DDBJ/ENA/GenBank under the accession JAAFZY000000000. The version described in this paper is version JAAFZY010000000.

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links