Hishamuddin Omar

Accumulation, depuration and distribution of cadmium and zinc in the green-lipped mussel Perna viridis (Linnaeus) under laboratory conditions

Ecotoxicological tests were conducted in the green-lipped mussel Perna viridis under laboratory conditions. Different rates of accumulation and depuration in soft tissues are found and this might be due to different mechanisms of metal binding and regulation. At the end of depuration, Cd levels in soft tissues of P. viridis were 10–30 times higher than before exposure, while Zn levels in soft tissues were almost similar to levels before exposure. These results indicate that P. viridis is a good biomonitoring organism for Cd but Zn levels might be actively regulated. It remains uncertain whether P. viridis is a good biomonitoring organism of environmental Zn contamination. However, the positive patterns, although different rates, of accumulation and depuration for Cd and Zn support the use of P. viridis as a biomonitoring agent for such metals.

Studies on the genetic variation of the green unicellular alga Haematococcus pluvialis (Chlorophyceae) obtained from different geographical locations using ISSR and RAPD molecular marker.

Haematococcus pluvialis (Flotow) is a unicellular green alga, which is considered to be the best astaxanthin-producing organism. Molecular markers are suitable tools for the purpose of finding out genetic variations in organisms; however there have been no studies conducted on ISSR or RAPD molecular markers for this organism. The DNA of 10 different strains of H. pluvialis (four strains from Iran, two strains from Finland, one strain from Switzerland and three strains from the USA) was extracted. A genetic similarity study was carried out using 14 ISSR and 12 RAPD primers. Moreover, the molecular weights of the bands produced ranged from 0.14 to 3.4 Kb. The PCA and dendrogram clustered the H. pluvialis strains into various groups according to their geographical origin. The lowest genetic similarity was between the Iran2 and USA2 strains (0.08) and the highest genetic similarity was between Finland1 and Finland2 (0.64). The maximum numbers of bands produced by the ISSR and RAPD primers were 35 and 6 bands, respectively. The results showed that ISSR and RAPD markers are useful for genetic diversity studies of Haematococcus as they showed geographical discrimination.

Sequence Analysis and Potentials of the Native RbcS Promoter in the Development of an Alternative Eukaryotic Expression System Using Green Microalga Ankistrodesmus convolutus

The availability of highly active homologous promoters is critical in the development of a transformation system and improvement of the transformation efficiency. To facilitate transformation of green microalga Ankistrodesmus convolutus which is considered as a potential candidate for many biotechnological applications, a highly-expressed native promoter sequence of ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (AcRbcS) has been used to drive the expression of β-glucuronidase (gusA) gene in this microalga. Besides the determination of the transcription start site by 5′-RACE, sequence analysis revealed that AcRbcS promoter contained consensus TATA-box and several putative cis-acting elements, including some representative light-regulatory elements (e.g., G-box, Sp1 motif and SORLIP2), which confer light responsiveness in plants, and several potential conserved motifs (e.g., CAGAC-motif, YCCYTGG-motifs and CACCACA-motif), which may be involved in light responsiveness of RbcS gene in green microalgae. Using AcRbcS promoter::gusA translational fusion, it was demonstrated that this promoter could function as a light-regulated promoter in transgenic A. convolutus, which suggested that the isolated AcRbcS promoter was a full and active promoter sequence that contained all cis-elements required for developmental and light-mediated control of gene expression, and this promoter can be used to drive the expression of heterologous genes in A. convolutus. This achievement therefore advances the development of A. convolutus as an alternative expression system for the production of recombinant proteins. This is the first report on development of gene manipulation system for unicellular green alga A. convolutus.

Accumulation of Heavy Metals (Zn, Cu, Pb, Cd) in Flat-Tree Oysters Isognomon Alatus Exposed to Pig Farm Effluent

Field experiments were conducted to measure the accumulation of heavy metals (Zn, Cu, Pb, Cd) in oysters Isognomon alatus transferred from the Sepang Kecil River (clean area) to the Sepang Besar River (polluted area), for a period of 6 months. Oysters were placed in an area near an effluent from pig farm. There were increase in all metals studied in the oysters introduced to the Sepang Besar River. The metals accumulated by transplanted oysters indicated chronic pollution by metals from the pig farm effluent. A significant difference was found between the accumulation rate of Zn and accumulation rates of the Cu, Pb and Cd. Accumulation rates of metals by oysters under field conditions were found to be 42.70, 1.77, 0.95 and 0.84 µg g m 1 month m 1 for Zn, Cu, Pb and Cd, respectively. It was also found that oysters have abilities to regulate their internal concentrations of metals over a range of external metal concentrations.

Efficiency of ligation-mediated PCR and TAIL-PCR methods for isolation of RbcS promoter sequences from green microalga Ankistrodesmus convolutus

Isolation of promoter sequences from known gene sequences is a tedious task in genome-related research. An efficient method of obtaining the promoter sequences is necessary in order to successfully use targeted promoters for genetic manipulations. Here, efficiency and usefulness of two PCR-based methods, namely: ligation-mediated PCR and thermal asymmetric interlaced (TAIL) PCR, for isolation of promoter sequences of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RbcS) gene from green microalga Ankistrodesmus convolutus (A. convolutus) were evaluated. The results showed that the amplification efficiency of TAIL-PCR was higher than that of the ligation-mediated PCR method, i.e. the amplified promoter fragments of 1.2 and 0.8 kb in length or promoter sequences of 813 and 606 bp (after eliminating the unreadable sequences). The use of TAIL-PCR described here presents a low cost and efficient strategy for the isolation of promoter sequences of known genes, especially in GC-rich regions, and species with little or no available genome information such as A. convolutus.

Heavy metal depuration in flat tree oysters isognomon alatus under field and laboratory conditions

Oysters Isognomon alatus containing high concentrations of Zn, Cu, Pb and Cd were collected from the Sepang Besar River, and transferred to the Sepang Kecil River where the native oysters contain low metal concentrations. Concentrations of heavy metals in oysters were measured monthly over six months. The concentrations of all metals decreased significantly (p<0.05) for Cd 87%, Pb 83%, Cu 78%, and Zn 59%. In addition, metal depuration in oysters was investigated under laboratory conditions. Oysters were exposed to 100 µg g−1 of metals for two weeks followed by one week of depuration. Our studies suggest that metals in oysters tend to be lost in the order, Cd>Pb>Cu>Zn. A comparison between laboratory and field data showed that depuration of metals under the laboratory conditions is significantly faster than in the field.

Relationship between Pb and Cd accumulations in house crow, their habitat, and food content from Klang area, Peninsular Malaysia

Heavy metal pollution has become a global concern due to accumulation in tissue and transferable effects to humans via the food chain. This study focused on monitoring the accumulation of cadmium (Cd) and lead (Pb) in surface soil and body content: bone, heart, brain, liver, lung, muscle, kidney, feathers, feces, and gizzard contents of house crow Corvus splendens in the Klang region, Malaysia. The results revealed the occurrence of Pb and Cd in all biological samples from house crows, food contents, and surface soil samples. Heart and kidney accrued high amounts of Cd, while high amounts of Pb were found to accumulate in bones and feathers. Major discrepancies were also discovered in the concentrations of metals between juvenile and adults, as well as female and male bird samples. Concentrations of Pb and Cd in house crow internal tissues correlated significantly with that of bird feathers, but none could be established with that of surface soil. In addition, a significant correlation was observed between Pb concentration in the internal tissues to that of the feces, but the same was not the case when compared with the surface soil concentration. Metal accrual in the house crows feathers and feces may be through a long-term transmission via the food chain, which are eliminated from feathers via molting. This may suggest the utility of molted breast feathers of house crow in the bio-monitoring of Cd and Pb contamination, whereas feces of house crow appear only to be suitable for the bio-monitoring of Pb contamination.

Risk Factors Associated with Peptic Ulcer Disease

Background: Helicobacter pylori (H. pylori) infection is usually acquired in early childhood. H. pylori infection is associated with several upper gastrointestinal disorders. Since H. pylori affects about 50% of the population in their lifetime therefore there is a necessity to examine the extent of the disease and to study the risk factors associated with H. pylori infection. The purpose of this study is to evaluate the rate of H. pylori infection among the target population. Methods: This study included one hundred seventy eight randomly selected participants by interview and questionnaire. The independent variables included in the questionnaire were: age, sex, weight, marital status, smoking, drink tea, drink coffee, type of drinking water during childhood and adulthood (filtered, unfiltered water). HpSAg test were used to detect antigen in stool specimen. Results: In crude analysis, the infection risk was associated with type of drinking water during childhood with P value=0.018. Tea drinking seemed to be a protective factor against H. pylori infection. Conclusions: The independent variables were considered as risk factors with peptic ulcer disease. H. pylori infection appears to be multifactorial. The results of this work supported the hypothesis that H. pylori acquisition occurs early in childhood and persist throughout life.

Effects of calcium supplementation on iron bioavailability from spirulina

Purpose – The purpose of this study is to determine the effect of calcium supplementation on the iron bioavailability from spirulina (SP) and ferrous sulphate (FE) as reference in iron deficient rats.Design/methodology/approach – Sixty‐four weanling male Sprague‐Dawley rats were first depleted of iron by giving low iron diet for a period of 28 days. The anaemic rats were repleted with iron sources from SP, spirulina+CaCO3 (SPC), FE, FeSO4+CaCO3 (FEC), normal diet (ND), normal diet+CaCO3 (NDC) for 21 days. Iron level of FE supplementation was twice the level of that in SP supplementation. Haematological variables were measured on the last day of preexperimental period and at the end of the repletion period.Findings – Paired samples t‐test at P<0.05 showed that haemoglobin (Hb) and haematocrit (Ht) was increased in all the groups. The diet with added calcium did not significantly inhibit haemoglobin repletion after 21 days in SP and FE. The haemoglobin repletion efficiency (HRE) was significantly higher in ...

Formulation of Cost-effective Medium Using Urea as a Nitrogen Source for Arthrospira platensis Cultivation under Real Environment

Even though Arthrospira is a well-known superfood, it is not extensively commercialized in developing countries like Malaysia due to the high production cost with low biomass yield. Based on literature, the algal production cost can be discounted by reducing the cost of medium utilizing cheaper and readily available chemicals. Therefore, the present study was conducted to Original Research Article Sukumaran et al.; ARRB, 22(2): 1-12, 2018; Article no.ARRB.38182 2 experiment the prospect of Arthrospira platensis cultivation in newly designed medium with commercial or industrial grade fertilizers under real environment. Consequently, growth and yield of A. platensis was investigated under outdoor condition using modified Kosaric medium (MKM) which was designed by substituting the major laboratory chemicals in standard Kosaric medium (SKM) with commercial grade baking soda, sea salt, urea, phosphoric acid, potassium hydroxide and Epsom salt. Urea as an alternative nitrogen resource to sodium nitrate was pulse-fed throughout the cultivation period. The algal growth was measured through optical density, biomass dry weight and chlorophyll a content. The algal yield was determined by calculating its productivity and specific growth rate. The growth and yield of A. platensis was significantly higher (p < 0.05) in MKM in terms of optical density with 2.541 ABS, biomass dry weight with 1.30 g L, chlorophyll a content with 12.96 mg L, productivity with 0.141 g L d and specific growth rate with 0.253 μ d compared to SKM in eight days of cultivation period. The present finding showed the potential of MKM in lowering the medium cost up to 97% compared to SKM without compromising the algal yield under natural condition with proper cultivation techniques such as preadaptation and fedbatch addition of urea in the late evening.