Displaying publications 1 - 20 of 338 in total

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  1. Fulltext Draft Genome Sequence of Klebsiella pneumoniae Isolate PR04
    Zulkifli MH, Teh LK, Lee LS, Zakaria ZA, Salleh MZ
    Genome Announc, 2013;1(4).
    PMID: 23950113 DOI: 10.1128/genomeA.00418-13
    Klebsiella pneumoniae PR04 was isolated from a patient hospitalized in Malaysia. The draft genome sequence of K. pneumoniae PR04 shows differences compared to the reference sequences of K. pneumoniae strains MGH 78578 and NTUH-K2044 in terms of their genomic structures.
  2. Phenotypic and genetic characterization of multidrug-resistant Staphylococcus aureus in the tropics of Southeast Asia
    Zulkeflle SNM, Yusaimi YA, Sugiura N, Iwamoto K, Goto M, Utsumi M, et al.
    Microbiology (Reading), 2016 12;162(12):2064-2074.
    PMID: 27902427 DOI: 10.1099/mic.0.000392
    Antibiotic resistance has become a major public health problem throughout the world. The presence of antibiotic-resistant bacteria such as Staphylococcus aureus and antibiotic resistance genes (ARGs) in hospital wastewater is a cause for great concern today. In this study, 276 Staph. aureus isolates were recovered from hospital wastewater samples in Malaysia. All of the isolates were screened for susceptibility to nine different classes of antibiotics: ampicillin, ciprofloxacin, gentamicin, kanamycin, erythromycin, vancomycin, trimethoprim and sulfamethoxazole, chloramphenicol, tetracycline and nalidixic acid. Screening tests showed that 100 % of Staph.aureus isolates exhibited resistance against kanamycin, vancomycin, trimethoprim and sulfamethoxazole and nalidixic acid. Additionally, 91, 87, 50, 43, 11 and 8.7 % of isolates showed resistance against erythromycin, gentamicin, ciprofloxacin, ampicillin, chloramphenicol and tetracycline, respectively. Based on these results, 100 % of isolates demonstrated multidrug-resistant (MDR) characteristics, displaying resistance against more than three classes of antibiotics. Of 276 isolates, nine exhibited resistance to more than nine classes of tested antibiotics; these were selected for antibiotic susceptibility testing and examined for the presence of conserved ARGs. Interestingly, a high percentage of the selected MDR Staph.aureus isolates did not contain conserved ARGs. These results indicate that non-conserved MDR gene elements may have already spread into the environment in the tropics of Southeast Asia, and unique resistance mechanisms against several antibiotics may have evolved due to stable, moderate temperatures that support growth of bacteria throughout the year.
  3. Fulltext The treatment of neck lymphangioma with intralesional injection of bleomycin
    Zulfiqar MA, Zaleha AM, Zakaria Z, Amin T
    Med J Malaysia, 1999 Dec;54(4):478-81.
    PMID: 11072465
    We report our experience with intralesional injection of bleomycin in the treatment of neck lymphangioma. From May 1995 to April 1998, 11 patients aged between 6 to 22 months were treated with intralesional bleomycin injection. Ultrasonography and computed tomography were used to assess and select the cases suitable for sclerotherapy. Patients with lesions encasing the internal jugular vein and the carotid artery were chosen. With the patient under sedation and using ultrasound guidance, the cysts were aspirated and bleomycin was injected at a dose of 0.5 mg/kg body weight. The number of procedures varied from 1 to 4 over a period of 8 months to 1 year. Patients were initially followed-up 3 monthly, then 6 monthly and subsequently yearly. In 4 patients, the neck mass was no longer visible (excellent response). In 5 patients, the neck mass had reduced to a size (more than 50% reduction) that was cosmetically acceptable (good response). There were 2 failures (poor response). There were no complications. Our results suggest that intralesional injection of bleomycin can be effectively used to treat selected cases of neck lymphangiomas.
  4. Functional outcome and quality of life following treatment for post-traumatic osteomyelitis of long bones
    Zayzan KR, Yusof NM, Sulong AF, Zakaria Z, Ab Rahman J
    Singapore Med J, 2020 Dec 02.
    PMID: 33264560 DOI: 10.11622/smedj.2020164
    INTRODUCTION: The clinical outcomes and factors associated with treatment failure of post-traumatic osteomyelitis have been investigated by many studies. However, limb functionality and quality of life following treatment for this condition have not been thoroughly studied.

    METHODS: This was a cross-sectional study that included 47 patients with post-traumatic osteomyelitis of the lower limb. Functional outcome was assessed using the Lower Extremity Functional Score (LEFS), and quality of life was assessed using the validated Malay version of Short Form-36 version 2.

    RESULTS: Mean follow-up time was 4.6 (range 2.3-9.5) years. Median age was 44 years. Osteomyelitis was located in the tibia for 26 patients and in the femur for 21 patients. Osteomyelitis was consequent to internal infection in 38 patients and due to infected open fractures in nine patients. 42 (89.4%) patients had fracture union and control of infection. Bone defect was found to be a significant contributing factor for treatment failure (p = 0.008). The median LEFS for the success group was 65 when compared to 49 for the failure group. Although the success group showed better scores with regard to quality of life, the difference between the two groups was not statistically significant.

    CONCLUSION: The success rate for post-traumatic osteomyelitis of the lower limb was high. The presence of a bone defect was associated with treatment failure. Successfully treated patients had significantly better functional outcomes than failed ones.

  5. Inoculation of Bacillus sphaericus UPMB-10 to young oil palm and measurement of its uptake of fixed nitrogen using the ¹⁵N isotope dilution technique
    Zakry FA, Shamsuddin ZH, Abdul Rahim K, Zawawi Zakaria Z, Abdul Rahim A
    Microbes Environ, 2012;27(3):257-62.
    PMID: 22446306
    There are increasing applications of diazotrophic rhizobacteria in the sustainable agriculture system. A field experiment on young immature oil palm was conducted to quantify the uptake of N derived from N₂ fixation by the diazotroph Bacillus sphaericus strain UPMB-10, using the ¹⁵N isotope dilution method. Eight months after ¹⁵N application, young immature oil palms that received 67% of standard N fertilizer application together with B. sphaericus inoculation had significantly lower ¹⁵N enrichment than uninoculated palms that received similar N fertilizers. The dilution of labeled N served as a marker for the occurrence of biological N₂ fixation. The proportion of N uptake that was derived from the atmosphere was estimated as 63% on the whole plant basis. The inoculation process increased the N and dry matter yields of the palm leaflets and rachis significantly. Field planting of young, immature oil palm in soil inoculated with B. sphaericus UPMB-10 might mitigate inorganic fertilizer-N application through supplementation by biological nitrogen fixation. This could be a new and important source of nitrogen biofertilizer in the early phase of oil palm cultivation in the field.
  6. Fulltext Small scale imaging using ultrasonic tomography
    Zakaria, Z., Fazalul Rahiman, M.H., Abdul Rahim, R., Megat Ali, M.S.A., Baharuddin, M.Y., Jahidin, A.H.
    Journal of Nuclear and Related Technologies, 2009;2009(1):266-281.
    MyJurnal
    Ultrasound technology progressed through the 1960’s from simple A-mode and B-mode scans to today’s M-mode and Doppler two dimensional (2-D) and even three dimensional (3-D) systems. Modern ultrasound imaging has its roots in sonar technology after it was first described by Lord John Rayleigh over 100 years ago on the interaction of acoustic waves with media. Tomography technique was developed as a diagnostic tool in the medical area since the early of 1970’s. This research initially focused on how to retrieve a cross sectional images from living or non-living things. After a decade, the application of tomography systems span into the industrial area. However, the long exposure time of medical radiation-based method cannot tolerate the dynamic changes in industrial process two phase liquid/gas flow system.. An alternative system such as a process tomography system, can give information on the nature of the flow regime characteristic. The overall aim of this paper is to investigate the use of a small scale ultrasonic tomography method based on ultrasonic transmission mode tomography for online monitoring of liquid/gas flow in pipe/vessel system through ultrasonic transceivers application. This non-invasive technique applied sixteen transceivers as the sensing elements to cover the pipe/vessel cross section. The paper also details the transceivers selection criteria, hardware setup, the electronic measurement circuit and also the image reconstruction algorithm applied. The system was found capable of visualizing the internal characteristics and provides the concentration profile for the corresponding liquid and gas phases.
  7. Fulltext Methanol extract of Bauhinia purpurea leaf possesses anti-ulcer activity
    Zakaria ZA, Abdul Hisam EE, Norhafizah M, Rofiee MS, Othman F, Hasiah AH, et al.
    Med Princ Pract, 2012;21(5):476-82.
    PMID: 22398984 DOI: 10.1159/000336593
    The aim of the present study was to determine the anti-ulcer activity of a methanol extract of Bauhinia purpurea leaf (MEBP).
  8. Bacterial reduction of Cr(VI) at technical scale--the Malaysian experience
    Zakaria ZA, Ahmad WA, Zakaria Z, Razali F, Karim NA, Sum MM, et al.
    Appl Biochem Biotechnol, 2012 Jul;167(6):1641-52.
    PMID: 22350941 DOI: 10.1007/s12010-012-9608-9
    The bacterial reduction of Cr(VI) from industrial wastewater was evaluated using a 2.0-m(3) bioreactor. Liquid pineapple waste was used as a nutrient for the biofilm community formed inside the bioreactor. The use of rubber wood sawdust as packing material was able to immobilize more than 10(6) CFU mL(-1) of Acinetobacter haemolyticus cells after 3 days of contact time. Complete reduction of 15-240 mg L(-1) of Cr(VI) was achieved even after 3 months of bioreactor operation. Cr(VI) was not detected in the final effluent fraction indicating complete removal of Cr from solution from the flocculation/coagulation step and the unlikely re-oxidation of Cr(III) into Cr(VI). Impatiens balsamina L. and Gomphrena globosa L. showed better growth in the presence of soil-sludge mixture compared to Coleus scutellarioides (L.) Benth. Significant amounts of Cr accumulated at different sections of the plants indicate its potential application in Cr phytoremediation effort. The bacterial-based system was also determined not to be detrimental to human health based on the low levels of Cr detected in the hair and nail samples of the plant operators. Thus, it can be said that bacterial-based Cr(VI) treatment system is a feasible alternative to the conventional system especially for lower Cr(VI) concentrations, where sludge generated can be used as growth supplement for ornamental plant as well as not detrimental to the health of the workers.
  9. Fulltext In vitro antiproliferative and antioxidant activities and total phenolic contents of the extracts of Melastoma malabathricum leaves
    Zakaria ZA, Rofiee MS, Mohamed AM, Teh LK, Salleh MZ
    J Acupunct Meridian Stud, 2011 Dec;4(4):248-56.
    PMID: 22196508 DOI: 10.1016/j.jams.2011.09.016
    The present study aims to determine the in vitro antiproliferative and antioxidant activities of various extracts from the leaves of Melastoma malabathricum using various established in vitro assays. The aqueous extract inhibited the proliferation of Caov-3 and HL-60 cell lines, while the chloroform extract exhibited antiproliferative activity against the Caov-3, HL-60, and CEM-SS cell lines. The methanol extract demonstrated antiproliferative activity against more cell lines, including the MCF-7, HeLa, Caov-3, HL-60, CEM-SS, and MDA-MB-231 cancer cell lines. Interestingly, all extracts did not inhibit the proliferation of 3T3 cells, thus indicating their noncytotoxic properties. Unlike the chloroform extracts, the aqueous and methanol extracts of M malabathricum (20, 100, and 500 μg/ml) produced high antioxidant activity for the superoxide scavenging assay with only the 500 μg/ml aqueous and methanol extracts exhibited high activity for the 2,2-diphenyl -1-picrylhydrazyl radical scavenging assay. The total phenolic content recorded for the aqueous, methanol, and chloroform extracts were 3344.2 ± 19.1, 3055.1 ± 8.7, and 92.5 ± 7.3 mg/100 g of gallic acid, respectively. The M malabathricum leaves possessed potential antiproliferative and antioxidant activities that could be attributed to its high content of phenolic compounds.
  10. In vivo antiulcer activity of the aqueous extract of Bauhinia purpurea leaf
    Zakaria ZA, Abdul Hisam EE, Rofiee MS, Norhafizah M, Somchit MN, Teh LK, et al.
    J Ethnopharmacol, 2011 Sep 2;137(2):1047-54.
    PMID: 21802502 DOI: 10.1016/j.jep.2011.07.038
    Bauhinia purpurea (Fabaceae) is a medicinal plant traditionally used to treat various ailments, including ulcers. In order to establish pharmacological properties of the leaf of Bauhinia purpurea, studies were performed on antiulcer activity of the plant's aqueous extract.
  11. In vivo antinociceptive and anti-inflammatory activities of dried and fermented processed virgin coconut oil
    Zakaria ZA, Somchit MN, Mat Jais AM, Teh LK, Salleh MZ, Long K
    Med Princ Pract, 2011;20(3):231-6.
    PMID: 21454992 DOI: 10.1159/000323756
    The present study was carried out to investigate the antinociceptive and anti-inflammatory activities of virgin coconut oil (VCO) produced by the Malaysian Agriculture Research and Development Institute (MARDI) using various in vivo models.
  12. Preliminary analysis of the anti-inflammatory activity of essential oils of Zingiber zerumbet
    Zakaria ZA, Mohamad AS, Ahmad MS, Mokhtar AF, Israf DA, Lajis NH, et al.
    Biol Res Nurs, 2011 Oct;13(4):425-32.
    PMID: 21112917 DOI: 10.1177/1099800410386590
    Nonsteroidal anti-inflammatory drugs (NSAIDs) have been widely used for the treatment of inflammation. However, despite their effectiveness, most NSAIDs cause various side effects that negatively affect the management of inflammation and, in part, pain. Thus, there is a need to search for new anti-inflammatory agents with few, or no, side effects. Natural products of plant, animal, or microorganism origin have been good sources of new bioactive compounds. The present study was carried out to evaluate the acute and chronic anti-inflammatory activities of the essential oil of the rhizomes of Zingiber zerumbet (Zingiberaceae) using the carrageenan-induced paw edema and cotton pellet-induced granuloma tests, respectively. The effect of the essential oil on inflammatory- and noninflammatory-mediated pain was also assessed using the formalin test. Essential oil of Z. zerumbet, at doses of 30, 100, and 300 mg/kg, was administered intraperitoneally to rats. The substance exhibited significant anti-inflammatory activity both in acute and chronic animal models. The essential oil also inhibited inflammatory- and noninflammatory-mediated pain when assessed using the formalin test. In conclusion, the essential oil of Z. zerumbet possessed anti-inflammatory activity, in addition to its antinociceptive activity, which may explain its traditional uses to treat inflammatory-related ailments.
  13. Anti-inflammatory activity of the aqueous extract of ficus deltoidea
    Zakaria ZA, Hussain MK, Mohamad AS, Abdullah FC, Sulaiman MR
    Biol Res Nurs, 2012 Jan;14(1):90-7.
    PMID: 21278166 DOI: 10.1177/1099800410395378
    Ficus deltoidea (Family Moraceae) leaves have been used traditionally by the Malays to treat ailments such as wounds, sores, and rheumatism. The aim of the present study was to determine the anti-inflammatory activity of the aqueous extract of F. deltoidea leaf (FDA) using acute and chronic inflammatory models. FDA, in the doses of 30, 100, and 300 mg/kg, was administered intraperitoneally in rats (n = 6) before the animals were subjected to the carrageenan-induced paw edema test, cotton pellet-induced granuloma test, and formalin test. The first two tests represent acute and chronic models of inflammation, respectively. The first and second phases of the formalin test represent neurogenic pain and inflammatory-mediated pain, respectively; thus, only the second phase was measured in the present study. Results showed that FDA exerted significant (p < .05) anti-inflammatory activity in all assays, with dose-response effects seen in the paw edema and formalin tests. In conclusion, the leaf of F. deltoidea possesses anti-inflammatory activity against acute and chronic inflammatory responses and against pain-associated inflammatory response. These findings justify the traditional uses of F. deltoidea leaves for treatment of inflammatory-mediated ailments.
  14. Antinociceptive, anti-inflammatory and antipyretic effects of Solanum nigrum aqueous extract in animal models
    Zakaria ZA, Sulaiman MR, Morsid NA, Aris A, Zainal H, Pojan NH, et al.
    Methods Find Exp Clin Pharmacol, 2009 Mar;31(2):81-8.
    PMID: 19455262 DOI: 10.1358/mf.2009.31.2.1353876
    The present study was carried out to evaluate the antinociceptive, anti-inflammatory and antipyretic effects of the aqueous extract of Solanum nigrum leaves using various animal models. The extract, at concentrations of 10, 50 and 100%, was prepared by soaking (1:20; w/v) air-dried powdered leaves (20 g) in distilled water (dH2O) for 72 h. The extract solutions were administered subcutaneously in mice/rats 30 min prior to the tests. The extract exhibited significant (P < 0.05) antinociceptive activity when assessed using the abdominal constriction, hot plate and formalin tests. The extract also produced significant (P < 0.05) anti-inflammatory and antipyretic activities when assessed using the carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests, respectively. Overall, these activities occurred in a concentration-dependent manner, except for the 50% concentration of the extract, which was not effective in the abdominal constriction test. In conclusion, the present study demonstrated that S. nigrum leaves possessed antinociceptive, anti-inflammatory and antipyretic effects and thus supported traditional claims of its medicinal uses.
  15. In vivo anti-nociceptive and anti-inflammatory activities of the aqueous extract of the leaves of Piper sarmentosum
    Zakaria ZA, Patahuddin H, Mohamad AS, Israf DA, Sulaiman MR
    J Ethnopharmacol, 2010 Mar 2;128(1):42-8.
    PMID: 20035852 DOI: 10.1016/j.jep.2009.12.021
    Ethnopharmacological relevance: Piper sarmentosum (Piperaceae) is a medicinal plant traditionally used by the Malays to treat headaches, toothaches, coughs, asthma and fever.

    Aim of the study: In order to establish the pharmacological properties of the leaf of this plant, studies were performed on anti-nociceptive and anti-inflammatory activities.

    Materials and methods: The aqueous extract of Piper sarmentosum (AEPS) was prepared in the doses of 30, 100 and 300 mg/kg. Anti-nociceptive activity of AEPS was evaluated by abdominal constriction and hot-plate tests. AEPS was also pre-challenged with 5mg/kg naloxone to determine the involvement of opioid receptors. Anti-inflammatory activity was evaluated using carrageenan-induced paw edema assay.

    Results: Subcutaneous administration of AEPS exhibited anti-nociceptive activity (P<0.05) in a dose-dependent manner in the abdominal constriction and hot-plate tests. Pre-treatment with naloxone completely (P<0.05) diminished the extract anti-nociceptive activity in both tests. The AEPS, at all doses used, exerted significant (P<0.05) anti-inflammatory activity in a dose-dependent manner.

    Conclusions: The AEPS exhibits opioid-mediated anti-nociceptive activity at the peripheral and central levels, as well as anti-inflammatory activity, which confirmed the traditional uses of the plant in the treatment of pain- and inflammatory-related ailments.
  16. Antinociceptive, antiinflammatory and antipyretic properties of Channa striatus fillet aqueous and lipid-based extracts in rats
    Zakaria ZA, Kumar GH, Mat Jais AM, Sulaiman MR, Somchit MN
    Methods Find Exp Clin Pharmacol, 2008 Jun;30(5):355-62.
    PMID: 18806894 DOI: 10.1358/mf.2008.30.5.1186084
    The present study was carried out to elucidate the antinociceptive, antiinflammatory and antipyretic properties of the aqueous and lipid-based extracts of Channa striatus fillet in rats. The antinociceptive activity was assessed using the formalin test, and the antiinflammatory and antipyretic activities were assessed using the carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests, respectively. Both types of extracts were prepared in concentrations of 10%, 50% and 100% by serial dilution in distilled water or dimethyl sulfoxide, respectively, and were administered subcutaneously 30 min prior to each test. Except for the 10% aqueous extract which exhibits activity only in the early phase, the extracts were found to exhibit significant (P < 0.05) activity in the early and late phases of the formalin test. Furthermore, the aqueous and lipid-based extracts were also found to show significant (P < 0.05) antiinflammatory activity, with the former showing a greater effect at the lowest concentration used. The lipidbased, but not the aqueous, extract was found to have significant (P < 0.05) activity in the pyrexia test. In conclusion, the present study demonstrated that C. striatus extracts possess antinociceptive, antiinflammatory and antipyretic activities.
  17. Effects of various nonopioid receptor antagonists on the antinociceptive activity of Muntingia calabura extracts in mice
    Zakaria ZA, Hassan MH, Nurul Aqmar MN, Abd Ghani M, Mohd Zaid SN, Sulaiman MR, et al.
    Methods Find Exp Clin Pharmacol, 2007 Oct;29(8):515-20.
    PMID: 18040526
    This study was carried out in mice to determine the nonopioid receptor signaling pathway(s) that might modulate the antinociceptive activity of the aqueous and chloroform extracts of Muntingia calabura (M. calabura) leaves, using the hot-plate test. The leaves of M. calabura were sequentially soaked [1:2 (w/v); 72 h] in distilled water (dH(2)O) and chloroform. The 50% concentration extracts were selected for this study based on the plant's previously established antinociceptive profiles. The mice (n = 7) were pretreated (s.c.) for 10 min with the selected nonopioid receptor antagonists, followed by the (s.c.) administration of the respective extract. The latency of discomfort was recorded at the interval time of 0.5, 1, 2, 3, 4 and 5 h after the extract administration. The 5 mg/kg atropine, 10 mg/kg phenoxybenzamine, 10 mg/kg yohimbine, 10 mg/kg pindolol, 1 mg/kg haloperidol and 10 mg/kg bicuculline caused significant (p < 0.05) reduction in the aqueous extract-induced antinociceptive activity. The 10 mg/kg phenoxybenzamine, 10 mg/kg yohimbine, 10 mg/kg pindolol and 10 mg/kg bicuculline caused significant (p < 0.05) reduction in the chloroform extract-induced antinociceptive activity. In conclusion, the central antinociceptive activity of M. calabura leaves appears to be involved in the modulation of various nonopioid receptor signaling pathways. Its aqueous extract antinociceptive activity is mediated via modulation of the muscarinic, alpha(1)-adrenergic, alpha(2)-adrenergic, beta-adrenergic, dopaminergic and GABAergic receptors, while its chloroform extract activity is mediated via modulation of the alpha(1)-adrenergic, alpha(2)-adrenergic, beta-adrenergic and GABAergic receptors.
  18. Biosorption and bioreduction of Cr(VI) by locally isolated Cr-resistant bacteria
    Zakaria ZA, Aruleswaran N, Kaur S, Ahmad WA
    Water Sci Technol, 2007;56(8):117-23.
    PMID: 17978439
    Cr(VI) biosorption and bioreduction ability of locally isolated Cr-resistant bacteria was investigated using the shake-flask technique. A mixture of S. epidermidis and B. cereus showed the highest minimum inhibitory concentration (MIC) level at 750 mg/L Cr(VI) followed by S. aureus and Bacillus sp. of 250 mg/L, and A. haemolyticus of 70 mg/L. From the Langmuir adsorption isotherm, the treatment of cells with heat-acid resulted in the highest amount of Cr(VI) adsorped (78.25 mg/g dry wt. for S. epidermidis) compared to heat-acetone (67.93 mg/g dry wt. Bacillus sp.), heat only (36.05 mg/g dry wt. S. epidermidis) or untreated cells (45.40 mg/g dry wt. S. epidermidis and B. cereus). FTIR analysis showed the involvement of amine groups in Cr(VI) adsorption. In the bioreduction study, A. haemolyticus was able to completely reduce Cr(VI) up to 50 mg/L.
  19. Biological detoxification of Cr(VI) using wood-husk immobilized Acinetobacter haemolyticus
    Zakaria ZA, Zakaria Z, Surif S, Ahmad WA
    J Hazard Mater, 2007 Sep 5;148(1-2):164-71.
    PMID: 17368716
    Acinetobacter haemolyticus, a Gram-negative aerobic locally isolated bacterium, immobilized on wood-husk showed the ability to detoxify Cr(VI) to Cr(III). Wood-husk, a natural cellulose-based support material, packed in an upward-flow column was used as support material for bacterial attachment. Around 97% of the Cr(VI) in wastewater containing 15 mg L(-1) of Cr(VI) was reduced at a flow rate of 8.0 mL min(-1). The wastewater containing Cr(VI) was added with liquid pineapple wastewater as nutrient source for the bacteria. Electron microscopic examinations of the wood-husk after 42 days of column operation showed gradual colonization of the wood-husk by bacterial biofilm. The use of 0.1% (v/v) formaldehyde as a disinfecting agent inhibited growth of bacteria present in the final wastewater discharge. This finding is important in view of the ethical code regarding possible introduction of exogenous bacterial species into the environment.
  20. Hexavalent chromium reduction by Acinetobacter haemolyticus isolated from heavy-metal contaminated wastewater
    Zakaria ZA, Zakaria Z, Surif S, Ahmad WA
    J Hazard Mater, 2007 Jul 19;146(1-2):30-8.
    PMID: 17188812
    Possible application of a locally isolated environmental isolate, Acinetobacter haemolyticus to remediate Cr(VI) contamination in water system was demonstrated. Cr(VI) reduction by A. haemolyticus seems to favour the lower concentrations (10-30 mg/L). However, incomplete Cr(VI) reduction occurred at 70-100 mg/L Cr(VI). Initial specific reduction rate increased with Cr(VI) concentrations. Cr(VI) reduction was not affected by 1 or 10 mM sodium azide (metabolic inhibitor), 10 mM of PO(4)3-, SO4(2-), SO(3)2-, NO3- or 30 mg/L of Pb(II), Zn(II), Cd(II) ions. However, heat treatment caused significant dropped in Cr(VI) reduction to less than 20% only. A. haemolyticus cells loses its shape and size after exposure to 10 and 50 mg Cr(VI)/L as revealed from TEM examination. The presence of electron-dense particles in the cytoplasmic region of the bacteria suggested deposition of chromium in the cells.
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