Displaying publications 61 - 80 of 118 in total

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  1. Isolation of Potential Bacteria as Inoculum for Biofloc Formation in Pacific Whiteleg Shrimp, Litopenaeus vannamei Culture Ponds
    Kasan NA, Ghazali NA, Ikhwanuddin M, Ibrahim Z
    Pak J Biol Sci, 2017;20(6):306-313.
    PMID: 29023055 DOI: 10.3923/pjbs.2017.306.313
    BACKGROUND AND OBJECTIVE: A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc.

    MATERIALS AND METHODS: For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC.

    RESULTS: Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp.

    CONCLUSION: In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.

  2. Effect of some environmental parameters on biobutanol production by Clostridium acetobutylicum NCIMB 13357 in date fruit medium
    Khamaiseh EI, Hamid AA, Yusoff WM, Kalil MS
    Pak J Biol Sci, 2013 Oct 15;16(20):1145-51.
    PMID: 24506014
    Date fruit juice contains high concentration of simple sugars ranging from 65 to 75% (w/w) in dry form. In this study, the potential of date fruit juice as biobutanol fermentation medium by C. acetobutylicum was investigated. The fermentation process was carried out at initial pH of 5, 6 and 7, incubation temperature of 30, 35 and 40 degrees C for 72 hours. The date fruit concentrations tested were 10, 20, 30 and 40 g L(-1). Medium containing 30 g L(-1) of date fruit at 35 degrees C incubation temperature with initial medium pH 7.0 gave the highest concentration of solvents of 3.1, 0.1 and 1.1 g L(-1) butanol, ethanol and acetone respectively. The yield and productivity of biobutanol were 0.32 g g(-1) and 0.044 g L(-1)/h respectively, while for total ABE were 0.45 g g(-1) and 0.06 g L(-1) h, respectively.
  3. Bromophenol blue binding to mammalian albumins and displacement of albumin-bound bilirubin
    Kim BB, Abdul Kadir H, Tayyab S
    Pak J Biol Sci, 2008 Oct 15;11(20):2418-22.
    PMID: 19137852
    Interaction of bromophenol blue (BPB) with serum albumins from different mammalian species, namely, human (HSA), bovine (BSA), goat (GSA), sheep (SSA), rabbit (RbSA), porcine (PSA) and dog (DSA) was studied using absorption and absorption difference spectroscopy. BPB-albumin complexes showed significant differences in the spectral characteristics, i.e., extent of bathochromic shift and hypochromism relative to the spectral features of free BPB. Absorption difference spectra of these complexes also showed variations in the position of maxima and absorption difference (deltaAbs.) values. Absorption difference spectra of different bilirubin (BR)-albumin complexes showed a significant blue shift accompanied by decrease in deltaAbs. values in presence of BPB which were indicative of the displacement of bound BR from its binding site in BR-albumin complexes. These changes in the difference spectral characteristics of BR-albumin complexes were more marked at higher BPB concentration. However, the extent of these changes was different for different BR-albumin complexes. Taken together, all these results suggest that BPB partially shares BR binding site on albumin and different mammalian albumins show differences in the microenvironment of the BR/BPB binding site.
  4. Biodiversity of termite (Insecta: Isoptera) in tropical peat land cultivated with oil palms
    Kon TW, Bong CF, King JH, Leong CT
    Pak J Biol Sci, 2012 Feb 01;15(3):108-20.
    PMID: 22866541
    Termites are the major decomposers in tropical region but yet their occurrences in oil palm plantation especially in peat soil are generally treated as pest. Study of termite species in peat land was conducted in selected oil palm plantations in North Sarawak with 5-7 years old palms and South Sarawak with 13-15 years old palms with two sites in each area. Results of quadrate (25 x 25 x 30 cm) sampling showed termite was significantly higher in relative density with increasing depth of soil (0-10 = 21.23, 10-20 = 42.52 and 20-30 cm = 81.12%) which could be advantaged from being predated by ants (Hymenoptera: Formicidae) which were higher in density from soil surface to 10 cm soil depth with relative density of 31.84%. Modified transect sampling (50x6 m) had successfully sampled 18 species of termites from 2 families (Rhinotermitidae and Termitidae), 5 subfamilies (Rhinotermitinae, Coptotermitinae, Termitinae, Macrotermitinae and Nasutitermitinae) and 11 genera (Coptotermes, Schedorhinotermes, Termes, Macrotermes, Nasutitermes, Globitermes, Amitermes, Parrhinotermes, Pericapritermes, Havilanditermes and Prohamitermes). Both plantation sites have termite dominantly feeding on rotten wood as a result of abundant dead woods. However, Coptotermes curvignathus Holmgren was identified to feed on the living tissues of oil palm causing damage or death of the tree. Study showed higher encounter of soil-feeding termite in longer established plantation. It indicates the gradually shifting of soil condition towards a stabilized environment which favors the successful settlement of soil feeder termite species. Termite control should be more targets specific to avoid harming beneficial termites.
  5. Rapid metastasis of breast cancer cells from primary tumour to liver
    Kumar SS, Radhakrishnan AK, Cheong SK
    Pak J Biol Sci, 2010 Apr 01;13(7):303-15.
    PMID: 20836285
    The aim of this study was to establish an animal model of mammary carcinoma metastasis to discern the in vivo effects of growth and spread of breast cancer. Six-week-old female BALB/c mice were inoculated with 4T1 murine breast cancer cells. Mice weight and primary tumour mass volume were regularly recorded to study the physical effects of a vigorously growing and spreading of cancer cell line. Gross and histological studies were carried out to determine the approximate day of metastatic onset. Production of IFN-gamma was assessed by ELISA to understand its role in tumour growth and metastasis. Lymphocyte markers such as CD8+, CD25 and CD49b were analysed to elucidate its role in tumour growth and progression. Present study showed that the metastatic onset occurs approximately 11 days after the mice were inoculated with the 4T1 murine breast cancer cells. Gross studies showed hepatosplenomegaly. The breast cancer cells from primary tumour were found to spread rapidly to the liver on day 11. IFN-gamma production was higher in inoculated mice serum compared to control mice serum. Higher numbers of CD8+, CD25 and CD49b cells were observed in the peripheral blood of inoculated mice, compared to control mice. In conclusion, the 4T1 murine breast cancer cells can migrate and metastasise rapidly to the liver, eliciting various immune responses.
  6. Large-scale culture of a tropical marine microalga Chaetoceros calcitrans (Paulsen) Takano 1968 at different temperatures using annular photobioreactors
    Lai JI, Yusoff FM, Shariff M
    Pak J Biol Sci, 2012 Jul 01;15(13):635-40.
    PMID: 24218933
    Outdoor mass culture of microalgae in the tropical area is important to minimize its production cost. This study evaluates the growth of Chaetoceros calcitrans in 120 L annular photobioreactors at indoor temperature (Treatment I, 25 +/- 2 degrees C) and outdoor tropical ambient temperature, (Treatment II, 30 +/- 6 degrees C). Each treatment was done in duplicates. For both treatments, C. calcitrans was first grown in starter columns of 10 L capacity for a period of 7 days at 25 +/- 2 degrees C. After 7 days, the 9 L culture was transferred to the annular photobioreactors and subsequently brought to a final volume of 100 L by adding 20 L fresh medium every 5 days. There was no significant difference (p > 0.05) in the dry weight of microalgae grown in natural light and those grown indoor. The results suggest that C. calcitrans can be grown in outdoor conditions, hence, saving time and microalgae production cost for the larviculture industry.
  7. Transformation of Morinda citrifolia via simple mature seed imbibition method
    Lee JJ, Ahmad S, Roslan HA
    Pak J Biol Sci, 2013 Dec 15;16(24):1913-21.
    PMID: 24517006
    Morinda citrifolia, is a valuable medicinal plant with a wide range of therapeutic properties and extensive transformation study on this plant has yet been known. Present study was conducted to establish a simple and reliable transformation protocol for M. citrifolia utilising Agrobacterium tumefaciens via direct seed exposure. In this study, the seeds were processed by tips clipping and dried and subsequently incubated in inoculation medium. Four different parameters during the incubation such as incubation period, bacterial density, temperature and binary vectors harbouring beta-glucuronidase (GUS) gene (pBI121 and pGSA1131), were tested to examine its effect on transformation efficiency. The leaves from the treated and germinated seedlings were analysed via Polymerase Chain Reaction (PCR), histochemical assay of the GUS gene and reverse transcription-PCR (RT-PCR). Results of the study showed that Agrobacterium strain LBA4404 with optical density of 1.0 and 2 h incubation period were optimum for M. citrifolia transformation. It was found that various co-cultivation temperatures tested and type of vector used did not affect the transformation efficiency. The highest transformation efficiency for M. citrifolia direct seed transformation harbouring pBI121 and pGSA1131 was determined to be 96.8% with 2 h co-cultivation treatment and 80.4% when using bacterial density of 1.0, respectively. The transformation method can be applied for future characterization study of M. citrifolia.
  8. Response of Coptotermes curvignathus (Isoptera: Rhinotermitidae) to formaldehyde catcher-treated particleboard
    Lee SH, H'ng PS, Peng TL, Lum WC
    Pak J Biol Sci, 2013 Nov 01;16(21):1415-8.
    PMID: 24511759
    The objective of this study is to investigate the feasibility of formaldehyde catcher as termites repellent. Single-layered UF-bonded particleboard was post-treated with formaldehyde catcher and heat respectively. Besides that, some boards were also produced with the formaldehyde catcher was added into the resin during the blending process, called add-in method. Particleboard post-treated with formaldehyde catcher reported the most severe attack. Heat-treated particleboard showed slightly better durability than the control blocks while the add-in catcher showed the best durability among three methods. A valid test was obtained as the termites survived the first week of the test. However, all the termites were found dead at the end of the test.
  9. Bioconversion of oil palm frond by Aspergillus niger to enhances it's fermentable sugar production
    Lim SH, Ibrahim D
    Pak J Biol Sci, 2013 Sep 15;16(18):920-6.
    PMID: 24502148
    The aim of this study was to develop an economical bioprocess to produce the fermentable sugars at laboratory scales Using Oil Palm Frond (OPF) as substrate in Solid State Fermentation (SSF). OPF waste generated by oil palm plantations is a major problem in terms of waste management. However, this lignocellulosic waste material is a cheap source of cellulose. We used OPF as substrate to produce fermentable sugars. The high content of cellulose in OPF promises the high fermentable sugars production in SSF. Saccharification of OPF waste by A. niger USMAI1 generates fermentable sugars and was evaluated through a solid state fermentation. Physical parameters, e.g., inoculum size, initial substrate moisture, initial pH, incubation temperature and the size of substrate were optimized to obtain the maximum fermentable sugars from oil palm fronds. Up to 77 mg of fermentable sugars per gram substrate was produced under the optimal physical parameter conditions. Lower productivity of fermentable sugars, 32 mg fermentable sugars per gram substrate was obtained under non optimized conditions. The results indicated that about 140.6% increase in fermentable sugar production after optimization of the physical parameters. Glucose was the major end component amongst the fermentable sugars obtained. This study indicated that under optimum physical parameter conditions, the OPF waste can be utilized to produce fermentable sugars which then convert into other products such as alcohol.
  10. Optimization of Culture Medium for the Growth of Candida sp. and Blastobotrys sp. as Starter Culture in Fermentation of Cocoa Beans (Theobroma cacao) Using Response Surface Methodology (RSM)
    Mahazar NH, Zakuan Z, Norhayati H, MeorHussin AS, Rukayadi Y
    Pak J Biol Sci, 2017;20(3):154-159.
    PMID: 29023007 DOI: 10.3923/pjbs.2017.154.159
    BACKGROUND AND OBJECTIVE: Inoculation of starter culture in cocoa bean fermentation produces consistent, predictable and high quality of fermented cocoa beans. It is important to produce healthy inoculum in cocoa bean fermentation for better fermented products. Inoculum could minimize the length of the lag phase in fermentation. The purpose of this study was to optimize the component of culture medium for the maximum cultivation of Candida sp. and Blastobotrys sp.

    MATERIALS AND METHODS: Molasses and yeast extract were chosen as medium composition and Response Surface Methodology (RSM) was then employed to optimize the molasses and yeast extract.

    RESULTS: Maximum growth of Candida sp. (7.63 log CFU mL-1) and Blastobotrys sp. (8.30 log CFU mL-1) were obtained from the fermentation. Optimum culture media for the growth of Candida sp., consist of 10% (w/v) molasses and 2% (w/v) yeast extract, while for Blastobotrys sp., were 1.94% (w/v) molasses and 2% (w/v) yeast extract.

    CONCLUSION: This study shows that culture medium consists of molasses and yeast extract were able to produce maximum growth of Candida sp. and Blastobotrys sp., as a starter culture for cocoa bean fermentation.

  11. Germination and seedling development of Trapa bispinosa Roxb
    Mirani OI, Harah ZM, Sidik BJ
    Pak J Biol Sci, 2012 Jul 01;15(13):653-7.
    PMID: 24218936
    Trapa bispinosa is a freshwater macrophyte occurring in stagnant or slow moving water streams. Information on assessment of seeds storage and germination of Trapa bispinosa is less available in literature. Dependence on fresh seeds abundance only from natural environment for plant propagation or cultivation may lead to insufficient supply of seeds due to various biotic and abiotic factors. This study evaluated the viability and germination of Trapa bispinosa seeds stored in zip-lock plastic bag at low temperature of 7 degrees C for six months and fresh seeds. In addition germinating seeds progressive development to juvenile plants was recorded and described. Experiments were conducted where stored and fresh seeds were soaked in 62 x 45 x 54 cm glass tanks filled with aged tap water to the level of 15 cm depth. Stored seeds showed low percentage germination of 2.82% compared to fresh seeds which was 71.19%. Eight distinct developmental stages were identified from germinating seeds to juvenile plants. Both stored and fresh seeds produced plants of similar morphology but stored seeds progressive development from germination, seedling to juvenile plants needed longer duration to achieve. The storage of seed at low temperature at 7 degrees C for six months showed reduced viability and also vigorousity. Improved methods should be developed for Trapa seeds storage taking into account of the seeds' endurance to dryness and moisture levels in order to maintained seeds viability for future uses either for production, research purposes or even conservation and restoration programs.
  12. Optimum dietary protein requirement of Malaysian mahseer (Tor tambroides) fingerling
    Misieng JD, Kamarudin MS, Musa M
    Pak J Biol Sci, 2011 Feb 01;14(3):232-5.
    PMID: 21870647
    The optimum dietary protein requirement of the Malaysian mahseer (Tor tambroides) fingerlings was determined in this study. In this completely randomized designed experiment, formulated diets of five levels of dietary protein (30, 35, 40, 45 and 50%) were tested on the T. tambroides fingerlings (initial body weight of 5.85 +/- 0.40 g), reared in aquarium fitted with a biofiltering system. The fingerlings were fed twice daily at 5% of biomass. The fingerling body weight and total length was taken at every two weeks. Mortality was recorded daily. The dietary protein had significant effects on the body weight gain and Specific Growth Rate (SGR) of the fingerlings. The body weight gain and SGR of fingerlings fed with the diet with the dietary protein level of 40% was significantly higher (p<0.05) than that of 30, 35 and 50%. The feed conversion ratio of the 40% dietary protein was the significantly lowest at 2.19 +/- 0.163. The dietary protein level of 40% was the most optimum for T. tambroides fingerlings.
  13. Selenium supplementation reduced oxidative stress in diethylnitrosamine-induced hepatocellular carcinoma in rats
    Mohamed J, Wei WL, Husin NN, Alwahaibi NY, Budin SB
    Pak J Biol Sci, 2011 Dec 01;14(23):1055-60.
    PMID: 22590839
    Selenium in the form of sodium selenite (SSE) is an essential micronutrient which known to possess antioxidant and anticancer properties. This study emphasizes the role of selenium on oxidative stress in experimental rats with N-diethylnitrosamine (DEN) initiated and 2-acetylaminofluorene (2-AAF) promoted multistage hepatocellular carcinogenesis (HCC). Rats were divided randomly into six groups: negative control, positive control (DEN+2-AAF), preventive group (pre-SEE 4 weeks+DEN), preventive control (respective control for preventive group), therapeutic group (DEN+post-SSE 12 weeks) and therapeutic control (respective control for therapeutic group). SSE (4 mg L(-1)) was given to animals before initiation and during promotion phase of HCC. The levels of total protein (TP), conjugated diens (CD), malondialdehyde (MDA), fluorescent pigment (FP), antioxidant activity (AOA) and DNA damage were measured. Supplementation of SSE before the initiation phase of carcinogenicity significantly increased TP and AOA level (p < 0.05) while it decreased the levels of CD, MDA, DNA damage and FP (p < 0.05). Supplementation of SSE during the promotion phase of carcinogenicity significantly decreased the DNA damage and FP level (p < 0.05) and there were negative correlation between the level of AOA and with the level of FP and CD. Thus, supplementation of SSE reduced the adverse changes which occur in liver cancer. However, the chemoprevention effect of SSE was more pronounced when it was supplemented before initiation phase of cancer when compared to promotion phase.
  14. Antibacterial and Antifouling Properties of the Horseshoe Crab Carcinoscorpius rotundicauda
    Mohd Faizal MN, Ismail N, M S Eldeen I, Mariam T
    Pak J Biol Sci, 2021 Jan;24(5):579-587.
    PMID: 34486333 DOI: 10.3923/pjbs.2021.579.587
    <b>Background and Objective:</b> Horseshoe crabs are widely used in both traditional and modern pharmaceutical applications. Most of the previous studies on horseshoe crabs focused on their blood which contains hemolymph and amoebocyte lysate. This study aimed to determine the potential antibacterial and antifouling properties of different extracts from the carapace and the book gills of <i>Carcinoscorpius rotundicauda</i>. <b>Materials and Methods:</b> The crude extracts were subjected to the bioactivity tests using the disc-diffusion and the inhibition of biofilm-formation measurement assays, for both the antibacterial and antifouling activities respectively. <b>Results:</b> The results obtained indicated that the carapace extracts had stronger antibacterial and antifouling effects compared to the book gills extracts. Extracts obtained from the male displayed more activity compared to the extracts from the female with a few exceptions. Methanol and acetone carapace crude extracts showed the best overall performance. A sterol compound was isolated from the carapace acetone extracts of the male of <i>C. rotundicauda</i>. However, the compound did not display strong activity compared to the crude extract. The compound might be contributing to the observed activity with other components through a synergistic effect. <b>Conclusion:</b> The presence of antibacterial and antifouling activities in the carapace and book gills extracts could be added to the complexity of the defence mechanisms of horseshoe crabs. The results of this study, therefore, may contribute to the knowledge of the defence mechanisms of <i>C. rotundicauda</i>. Further research is needed to determine the bioactivities of other parts of the animal and to explore their potential applications.
  15. Morphological alteration in mitochondria following diclofenac and ibuprofen administration
    Moorthy M, Fakurazi S, Ithnin H
    Pak J Biol Sci, 2008 Aug 01;11(15):1901-8.
    PMID: 18983031
    This study was conducted to identify and to compare the mitochondrial morphological alterations in livers of rats treated with various doses of diclofenac and ibuprofen. Hundred and forty-four male Sprague Dawley rats were dosed with 3, 5 and 10 mg kg(-1) diclofenac and ibuprofen in saline via intraperitoneal injection for 15 days. The control group was administered with saline in a similar manner. Four rats were euthanised every 3 days until day 15. While 200 mg kg(-1) diclofenac and ibuprofen-treated rats (n = 4) were euthanized 10 h posttreatment. The livers were removed, cleaned and a section across the right lobe was taken and fixed in 4% (v/v) glutaraldehyde for electron microscopy analysis and the remaining samples were kept at -80 degrees C for Western blot analysis. Five milligram per kilogram and 10 mg kg(-1) diclofenac-administered rats for 15 days revealed the presence of enlarged mitochondria, irregular and ruptured mitochondrial membranes. While rats administered with 10 mg kg(-1) ibuprofen also showed the presence of mitochondria with irregular membrane structure and ruptured membranes. Western blotting analysis of mitochondrial fractions revealed the expression of cytochrome c in all samples and complete absence of cytochrome c expression in the cytosolic fraction of all samples after day 15. Analysis in 200 mg kg(-1) diclofenac and ibuprofen-treated groups, revealed expression of cytochrome c in both mitochondrial and cytosolic fractions. This observation indicates that both diclofenac and ibuprofen may alter the morphology of mitochondria, leading to cytochrome c release into the cytosol. Further studies needs to be conducted to investigate on the activity of the mitochondria following both treatments.
  16. Enhancement of biodegradation of crude petroleum-oil in contaminated water by the addition of nitrogen sources
    Mukred AM, Hamid AA, Hamzah A, Yusoff WM
    Pak J Biol Sci, 2008 Sep 01;11(17):2122-7.
    PMID: 19266926
    Addition of nitrogen sources as supplementary nutrient into MSM medium to enhance biodegradation by stimulating the growth four isolates, Acinetobacter faecalis, Staphylococcus sp., Pseudomonas putida and Neisseria elongata isolated from petroleum contaminated groundwater, wastewater aeration pond and biopond at the oil refinery Terengganu Malaysia was investigated. The organic nitrogen sources tested not only supported growth but also enhances biodegradation of 1% Tapis crude oil. All four isolates showed good growth especially when peptone was employed as the organic nitrogen compared to growth in the basal medium. Gas chromatography showed that more then 91, 93, 94 and 95% degradation of total hydrocarbon was observed after 5 days of incubation by isolates Pseudomonas putida, Neisseria elongate, Acinetobacter faecalis and Staphylococcus sp., respectively.
  17. Growth enhancement of effective microorganisms for bioremediation of crude oil contaminated waters
    Mukred AM, Abd-Hamid A, Hamzah A, Yusoff WM
    Pak J Biol Sci, 2008 Jul 01;11(13):1708-12.
    PMID: 18819623
    The bioremediation of polluted groundwater, wastewater aeration pond and biopond sites was investigated using bacteria isolated from these sites located at the oil refinery Terengganu Malaysia. Out of 62 isolates, only 16 isolates from groundwater (8) and wastewater aeration pond (3) and biopond (5) were chosen based on growth medium containing 1% (v/v) Tapis crude oil. Only four isolates; Acinetobacter faecalis, Staphylococcus sp., Pseudomonas putida and Neisseria elongata showed percentage biodegradation of crude oil more than 50% after 5 days using Mineral Salts Medium (MSM). The effect of physical parameters (temperature, pH and agitation) on growth by all four strains showed a maximum growth in MSM medium with 1% Tapis crude oil at 37 degrees C with pH 7 and agitation of 130 rpm.
  18. Evaluating ligand-receptor networks of TGF-beta with membrane computing
    Muniyandi RC, Zin AM
    Pak J Biol Sci, 2011 Dec 15;14(24):1100-8.
    PMID: 22335049
    Ligand-Receptor Networks of TGF-beta plays essential role in transmitting a wide range of extracellular signals that affect many cellular processes such as cell growth. However, the modeling of these networks with conventional approach such as ordinary differential equations has not taken into account, the spatial structure and stochastic behavior of processes involve in these networks. Membrane computing as the alternatives approach provides spatial structure for molecular computation in which processes are evaluated in a non-deterministic and maximally parallel way. This study is carried out to evaluate the membrane computing model of Ligand-Receptor Networks of TGF-beta with model checking approach. The results show that membrane computing model has sustained the behaviors and properties of Ligand-Receptor Networks of TGF-beta. This reinforce that membrane computing is capable in analyzing processes and behaviors in hierarchical structure of cell such as Ligand-Receptor Networks of TGF-beta better than the deterministic approach of conventional mathematical models.
  19. Determination of physical processes influencing Chl a distribution using remotely sensed images
    Mustapha AM, Lihan T, Saitoh S
    Pak J Biol Sci, 2011 Jan 15;14(2):82-90.
    PMID: 21916257
    In management of the Japanese scallop Mizuhopecten yessoensis culture, it is important to understand the phytoplankton bloom development in the coastal region of the Okhotsk Sea. Variations in food available to this benthic bivalve are a primary environmental factor affecting growth in nature. This paper determined the seasonal variability of Chlorophyll a (Chl a) at the scallop farming region in the Okhotsk Sea from 1998 to 2004 using satellite imageries. Satellite images were processed using default NASA coefficients and community-standard algorithms as implemented by Sea DAS. Spatial and temporal variation of Chl a was determined by EOF analysis. The Chl a concentration showed high seasonal and interannual variability. Peak of Chl a concentration occurred in spring followed by autumn and summer. This was evident in the Empirical Orthogonal Function (EOF) analysis. The spatial pattern of the first mode of EOF analysis of Chl a revealed intensified Chl a at the shelf and offshore areas in spring and autumn (51.8% of variance). The second mode explained 14.2% of the variance indicating enhancement of spring (April-May) Chl a pattern in the frontal area along the coast. Meanwhile, the third mode captured 9.0% of the variability demonstrating high Chl a extending seaward from the shelf area during late autumn. These seasonal variability of Chl a resulted from the variability in occurrences of physical processes associated with retreat of sea ice in spring, advection of Soya Warm Current in summer and intrusion of East Sakhalin Current in autumn.
  20. Occurrence of Plesiomonas shigelloides in cultured red hybrid tilapia (Oreochromis niloticus) from tropical rivers, east coast Malaysia
    Nadirah M, Ruhil HH, Jalal KC, Najiah M
    Pak J Biol Sci, 2012 Jun 15;15(12):600-3.
    PMID: 24191623
    A total of 182 isolates of Plesiomonas shigelloides were identified from 40 healthy red hybrid tilapia, Oreochromis niloticus cultured at two important rivers in Terengganu, Malaysia namely Como River and Terengganu River from east coast Malaysia. P. shigelloides count in Digestive Tract Content (DTC) and Muscle (MUS) of red hybrid tilapia cultured at Terengganu River was 1000-fold higher than Como River. Antibiotic susceptibility test was also performed on Plesiomonas shigelloides isolates. The incidence of antibiotic resistance was higher in Plesiomonas shigelloides isolated from red hybrid tilapia cultured at Terengganu River compared to Como river. Thus, the findings of the study indicate that P. shigelloides from tilapia muscle and an intestine could be an alarming for serious public health risk to consumers.
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