This study evaluated the use of alginate-immobilized bentonite to remove Cu(II) as an alternative to mitigate clogging problems. The adsorption efficacy (under the influence of time, pH and initial Cu(II) concentration) and reusability of immobilized-bentonite (1% w/v bentonite) was tested against plain alginate beads. Results revealed that immobilized bentonite demonstrated significantly higher sorption efficacy compared to plain alginate beads with 114.70 and 94.04 mg Cu(II) adsorbed g(-1) adsorbent, respectively. Both sorbents were comparable in other aspects where sorption equilibrium was achieved within 6 h, with optimum pH between pH 4 and 5 for adsorption, displayed maximum adsorption capacity at initial Cu(II) concentrations of 400 mg l(-1), and demonstrated excellent reusability potential with desorption greater than 90% throughout three consecutive adsorption-desorption cycles. Both sorbents also conformed to Langmuir isotherm and pseudo-second order kinetic model. Immobilized bentonite is therefore recommended for use in water treatments to remove Cu(II) without clogging the system.
Cu(II) removal efficacies of alginate-immobilized Trichoderma asperellum using viable and non-viable forms were investigated with respect to time, pH, and initial Cu(II) concentrations. The reusability potential of the biomass was determined based on sorption/desorption tests. Cu(II) biosorption by immobilized heat-inactivated T. asperellum cells was the most efficient, with 134.22mg Cu(II) removed g(-1) adsorbent, compared to immobilized viable cells and plain alginate beads (control) with 105.96 and 94.04mg Cu(II) adsorbed g(-1) adsorbent, respectively. Immobilized non-viable cells achieved equilibrium more rapidly within 4h. For all biosorbents, optimum pH for Cu(II) removal was between pH 4 and 5. Reusability of all biosorbents were similar, with more than 90% Cu(II) desorbed with HCl. These alginate-immobilized cells can be applied to reduce clogging and post-separation process incurred from use of suspended biomass.
Endophytes are novel sources of natural bioactive compounds. This study seeks endophytes that produce the anticancer enzyme l-asparaginase, to harness their potential for mass production. Four plants with anticancer properties; Cymbopogon citratus, Murraya koenigii, Oldenlandia diffusa and Pereskia bleo, were selected as host plants. l-Asparaginase-producing endophytes were detected by the formation of pink zones on agar, a result of hydrolyzes of asparagine into aspartic acid and ammonia that converts the phenol red dye indicator from yellow (acidic condition) to pink (alkaline condition). The anticancer enzyme asparaginase was further quantified via Nesslerization. Results revealed that a total of 89 morphotypes were isolated; mostly from P. bleo (40), followed by O. diffusa (25), C. citratus (14) and M. koenigii (10). Only 25 of these morphotypes produced l-asparaginase, mostly from P. bleo and their asparaginase activities were between 0.0069 and 0.025 μM mL(-1) min(-1). l-Asparaginase producing isolates were identified as probable species of the genus Colletotrichum, Fusarium, Phoma and Penicillium. Studies here revealed that endophytes are good alternative sources for l-asparaginase production and they can be sourced from anticancer plants, particularly P. bleo.
Triphenylmethane dyes (TPM) are recalcitrant colorants brought into the environment. In this study, a lesser-known white rot fungus Coriolopsis sp. (1c3), isolated from compost of Empty Fruit Bunch (EFB) of oil palm, was explored for its decolorization potential of TPM dyes. The isolate 1c3 demonstrated good decolorization efficiencies in the treatment of Crystal Violet (CV; 100 mg l(-1)), Methyl Violet (MV; 100 mg l(-1)) and Cotton Blue (CB; 50 mg(-1)), with 94%, 97% and 91%, within 7, 7 and 1 day(s), respectively. Malachite Green (MG; 100 mg l(-1)) was the most recalcitrant dye, with 52% decolorization after 9 days. Dye removal by 1c3 was presumably via biosorption, whereby the process was determined to be influenced by fungal biomass, initial dye concentrations and oxygen requirements. Biodegradation was also a likely mechanism responsible for dye removal by 1c3, occurred as indicated by the reduction of dye spectra peaks. Detection of laccase, lignin peroxidase and NADH-DCIP reductase activities further substantiate the possible occurrence of biodegradation of TPM dyes by 1c3.
This systematic review was conducted to develop a conceptual framework that addresses various factors associated with return to work among cancer survivors. Databases Medline, EMBASE, ProQuest, PubMed and ScienceDirect were systematically searched using medical subject headings [MeSH] for studies published in English from 1990 to 2013. Studies that described adult cancer patients' self-reported data or patients' point of view on factors associated with return to work or employment status following cancer diagnosis were included. Articles selection was conducted in three steps: selection based on title and abstract, retrieval of full text and additions of articles from reference lists and recommendations from experts. Disagreement in data extraction was solved by consultation of third reviewer. Out of twenty seven articles, breast cancer was the most studied type of cancer (30%) while colorectal cancer was studied independently in two articles (7.4%). Conceptual framework on return to work identifies factors under environmental, personal, work demand, work ability, health status and financial factors. Extensive search of scientific databases over last 24 years and the development of the conceptual frame-work are the strength of this review. Conceptual framework reveals the various factors including non-medical factors associated with return to work upon cancer diagnosis. It serves as a reminder to the policy makers to focus on modifiable factors as potential areas for intervention to assist cancer survivors return to work, especially those with little financial assistance and health insurance.
This study aimed to establish the colonization behavior and proliferation potential of three endophytes and one pathogen Ganoderma boninense (Gb) introduced into oil palm ramets (host model). The endophytes selected were Diaporthe phaseolorum (WAA02), Trichoderma asperellum (T2), and Penicillium citrinum (BTF08). Ramets were first inoculated with 100 mL of fungal cells (106 cfu mL-1) via soil drenching. For the next 7 days, ramets were sampled and subjected to three different assays to detect and identify fungal colonization, and establish their proliferation potential in planta. Plate assay revealed the presence of endophytes in root, stem and leaf tissues within 7 days after inoculation. Polymerase Chain Reaction (PCR) detected and identified the isolates from the plant tissues. The ergosterol assay (via high performance liquid chromatography, HPLC) confirmed the presence of endophytes and Gb in planta. The increase in ergosterol levels throughout 49 days was however insignificant, suggesting that proliferation may be absent or may occur very slowly in planta. This study strongly suggests that the selected endophytes could colonize the host upon inoculation, but proliferation occurs at a slower rate, which may subsequently influence the biocontrol expression of endophytes against the pathogen.
Next generation sequencing (NGS) enables rapid analysis of the composition and diversity of microbial communities in several habitats. We applied the high throughput techniques of NGS to the metagenomics study of endophytic bacteria in Aloe vera plant, by assessing its PCR amplicon of 16S rDNA sequences (V3-V4 regions) with the Illumina metagenomics technique used to generate a total of 5,199,102 reads from the samples. The analyses revealed Proteobacteria, Firmicutes, Actinobacteria and Bacteriodetes as the predominant genera. The roots have the largest composition with 23% not present in other tissues. The stems have more of the genus-Pseudomonas and the unclassified Pseudomonadaceae. The α-diversity analysis indicated the richness and inverse Simpson diversity index of the bacterial endophyte communities for the leaf, root and stem tissues to be 2.221, 6.603 and 1.491 respectively. In a similar study on culturable endophytic bacteria in the same A. vera plants (unpublished work), the dominance of Pseudomonas and Bacillus genera was similar, with equal proportion of four species each in root, stem and leaf tissues. It is evident that NGS technology captured effectively the metagenomics of microbiota in plant tissues and this can improve our understanding of the microbial-plant host interactions.
This study aims to determine the prevalence and associated factors of noise-induced hearing loss (NIHL) among vector control workers in the state of Negeri Sembilan, Malaysia. This was an analytical cross-sectional study conducted on 181 vector control workers who were working in district health offices in a state in Malaysia. Data were collected using a self-administered questionnaire and audiometry. Prevalence of NIHL was 26% among this group of workers. NIHL was significantly associated with the age-group of 40 years and older, length of service of 10 or more years, current occupational noise exposure, listening to loud music, history of firearms use, and history of mumps/measles infection. Following logistic regression, age of more than 40 years and noise exposure in current occupation were associated with NIHL with an odds ratio of 3.45 (95% confidence interval = 1.68-7.07) and 6.87 (95% confidence interval = 1.54-30.69), respectively, among this group of vector control workers.
Twenty-nine culturable bacterial endophytes were isolated from surface-sterilized tissues (root, stem and leaf) of Aloe vera and molecularly characterized to 13 genera: Pseudomonas, Bacillus, Enterobacter, Pantoea, Chryseobacterium, Sphingobacterium, Aeromonas, Providencia, Cedecea, Klebsiella, Cronobacter, Macrococcus and Shigella. The dominant genera include Bacillus (20.7%), Pseudomonas (20.7%) and Enterobacter (13.8%). The crude and ethyl acetate fractions of the metabolites of six isolates, species of Pseudomonas, Bacillus, Chryseobacterium and Shigella, have broad spectral antimicrobial activities against pathogenic Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Streptococcus pyogenes and Candida albicans, with inhibition zones ranging from 6.0 ± 0.57 to 16.6 ± 0.57 mm. In addition, 80% of the bacterial endophytes produced 1,1-diphenyl-2-picrylhydrazyl (DPPH) with scavenging properties of over 75% when their crude metabolites were compared with ascorbic acid (92%). In conclusion, this study revealed for the first time the endophytic bacteria communities from A. vera (Pseudomonas hibiscicola, Macrococcus caseolyticus, Enterobacter ludwigii, Bacillus anthracis) that produce bioactive compounds with high DPPH scavenging properties (75-88%) and (Bacillus tequilensis, Pseudomonas entomophila, Chryseobacterium indologenes, Bacillus aerophilus) that produce bioactive compounds with antimicrobial activities against bacterial pathogens. Hence, we suggest further investigation and characterization of their bioactive compounds.
The aim of this study was to determine the prevalence of job stress among secondary school teachers using Karasek Job Content Questionnaire (JCQ), the association between salivary cortisol, salivary IgA, and sociodemographic characteristics, and the association between log cortisol, IgA levels, and job strain categories. A cross-sectional study was undertaken using JCQ and salivary cortisol and IgA samples. Cluster sampling was done yielding 302 respondents. The prevalence of stress among all teachers was 20.2%. Being a Malay, teaching experience of 5 to 10 years, and those without a supervisor's support had higher prevalence of high job strain. Teachers in the 31 to 40 years age bracket, educating handicapped children with the absence of supervisor support exhibited higher stress levels with lower log salivary IgA levels. Further studies must be conducted using salivary biomarkers to study the in-depth relationship of stress, extending into other occupational groups.