Isolation and Characterization of a Molybdenum-reducing and Phenolic- and Catechol-degrading Enterobacter SP. Strain Saw-2

Molybdenum is an emerging pollutant worldwide. The objective of this study is to isolate molybdenum-reducing bacterium with the ability to grow on phenolic compounds (phenol and catechol). The screening process was carried out on a microplate. The bacterium reduced molybdenum in the form of sodium molybdate to molybdenum blue (Mo-blue). The bacterium required a narrow pH range for optimal reduction of molybdenum, i.e. between pH 6.3 and 6.8, with temperature between 34 and 37 oC. Molybdate reduction to Mo-blue was best supported by glucose as the carbon source. However, both phenol and catechol could not support molybdate reduction. Other requirements for molybdate reduction included sodium molybdate concentrations between 15 and 30 mM, and phosphate concentration of 5.0 mM. The bacterium exhibited a Mo-blue absorption spectrum with a shoulder at 700 nm and a maximum peak near the infrared region at 865 nm. The Mo-reducing bacterium was partially identified as Enterobacter sp. strain Saw-2. The capability of this bacterium to grow on toxic phenolic compounds and to detoxify molybdenum made it a significant agent for bioremediation

Identification of arsenic accumulator from traditional upland rice genotypes: A field survey in interior division, North Borneo

The Pan Borneo Highway provide traditional farmers better access to modern agronomic products that changes the rice agricultural management practices in rural areas. This study provides baseline data on selected heavy metal (As, Cd, Cr, Cu, Fe, Ni, Pb, Zn) concentration in rice and rhizosphere soil of four traditional rice landraces (Lantai, Tesik, Kembulaung & Sepulut) that was cultivated by the Dusun Minokok ethnic group residing in the small district of Sook, Interior Division, North Borneo. Heavy metals in soils and rice were determined by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The soil pH value for all rice landraces except Lantai had increased in between the rice life cycle at the vegetative and reproductive phase. Certain heavy metals bioavailability had decreased at reproductive phase when soil pH had increased. Cd and Cr was not detected in any rice landraces grains. None of the heavy metals concentration for all rice landraces had exceed the maximum allowable limit of Malaysia Food Regulation 1985. However, arsenic was efficiently mobile from root to grain of the late-maturing rice landraces’ Kembulaung and Sepulut. The Kembulaung and Sepulut landrace is an accumulator of arsenic with Enrichment Factor value more than 11 and 2 respectively. Increase of As phytoavailability in this cultivation area might pose health hazard if not manage sustainably

Lactic acid bacteria and their bacteriocins: new potential weapons in the fight against methicillin-resistant Staphylococcus aureus

Alternative solutions are eminently needed to combat the escalating number of infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Bacteriocins produced by lactic acid bacteria are promising candidates for next-generation antibiotics. Studies have found that these stable and nontoxic ribosomally synthesized antimicrobial peptides exhibit significant potency against other bacteria, including antibiotic-resistant strains. Here the authors review previous studies on bacteriocins that have been effectively employed to manage MRSA infections. The authors' review focuses on the beneficial traits of bacteriocins for further application as templates for the design of novel drugs. Treatments that combine bacteriocins with other antimicrobials to combat pervasive MRSA infections are also highlighted. In short, future studies should focus on the pharmacodynamics and pharmacokinetics of bacteriocins–antimicrobials to understand their interactions, as this aspect would likely determine their efficacy in MRSA inhibition

Alteration in morphological features of Puntius javanicus liver exposed to copper sulfate

The environmental toxicants such as copper are known to affect vital organ especially liver. This study examined the effects of copper sulfate (CuSO4 ) on the liver morphological structure of P. javanicus. The untreated control, 0.1 and 0.3 mg/L CuSO4 treated groups displayed normal polygonal structure of the hepatocyte. However, at the concentrations of 0.5, 1.0 and 5.0 mg/L CuSO4 , the hepatostructure was significantly affected, as shown by the increasing number of dilation and congestion of sinusoids, vacuolation, macrophage activities and peliosis. The damage level and HSI value were increased while the number of hepatic nuclei per mm2 was decreased with the increasing of copper concentration. In conclusion, this study shows that the degree of liver damage in P.javanicus is dependent to the dose exposure

Characterisation of cholinesterase from kidney tissue of Asian seabass (Lates calcarifer) and its inhibition in presence of metal ion

Aim: The cholinesterase (ChE) based inhibition studies from fish were investigated and presented here emerged to be one of the great potential biomarkers for heavy metals monitoring. Methodology: In this study, the capability of ChE extracted from the kidney of Lates calcarifer was assessed for of metal. ChE was purified through ammonium sulphate precipitation and ion exchange chromatography. Results: The purified enzyme gave 12 fold purification with the recovery of 12.17% with specific activity of 2.889 U mg-1. The Michaelis-Menten constant (Km) and Vmax value obtained was 0.1426 mM and 0.0217 �mol min-1mg-1, respectively. The enzyme has the ability to hydrolyse acetylthiocholine iodide (ATC) at a faster rate compared to other two synthetic substrates, propionylthiocholine iodide (PTC) and butyrylthiocholine iodide (BTC). ChE gave highest activity at 20-30�C in Tris-HCl buffer pH 8.0. The results showed that cholinesterase from L. calcarifer kidney was very sensitive to sensitive to copper and lead after being tested argentum, arsenic, cadmium, chromium, copper, cobalt, mercury, nickel, lead and zinc. Interpretation: The effect of heavy metals studied on the activity of ChE differed from each other. The result of the study can be used as a tool for further developing a biomarker for the detection of heavy metals in aquatic ecosystems. In addition, the information can also be used for designing a kit, that would give a rapid and accurate result

Enzyme inhibition-based biosensors using Acetylcholinesterase from Monopterus albus for detection of carbamates contamination

Insecticides are an example of an environmental contaminant that can cause harmful effects on various types of organisms. Implementation of continuous monitoring program is needed to ensure the level of contamination can be controlled. In this present study, acetylcholinesterase (AChE) from the brain of Monopterus albus was elucidated to determine the potential alternative source of biosensor kit, which is sensitive towards various insecticides, especially carbamates. AChE from M. albus brain was extracted and purified through ammonium sulfate precipitation followed by procainamide-based affinity chromatography. Carbamate insecticides were used, such as bendiocarb, carbaryl, carbofuran, methomyl, and propoxur, to test their ability to inhibit AChE activity. Bendiocarb and methomyl show the capability to inhibit almost half of the enzyme activity at 51.05 and 51.20 %, respectively, while carbaryl, propoxur, and carbofuran inhibit 43.03, 42.80, and 15.06 %, respectively. Bendiocarb and methomyl were selected, and M. albus AChE was separately exposed with different concentrations of those carbamates and half maximal inhibitory concentration; IC50 was determined at 0.874 and 1.639 ppm, respectively. A field trial was conducted by testing the enzyme with various vegetable samples. All samples show no significant effect on AChE activity, meaning there was no existence of insecticides in each sample (p > 0.05). This study could be used as an alternative source for developing biosensor kits for the environmental monitoring program