Nonlinear process modeling of fructosyltransferase (FTase) using bootstrap re-sampling neural network model

Recently, the increased demand of fructooligosaccharides (FOS) as a functional food has alarmed researchers to screen and identify new strains capable of producing fructosyltransferase (FTase). FTase is the enzyme that converts the substrate (sucrose) to glucose and fructose. The characterization of complex sugar such as table sugar, brown sugar, molasses, etc. will be carried out and the sugar that contained the highest sucrose concentration will be selected as a substrate. Eight species of macro-fungi will be screened for its ability to produce FTase and only one strain with the highest FTase activity will be selected for further studies. In this work, neural networks (NN) have been chosen to model the process based on their excellent ‘resume’ in coping with nonlinear process. Bootstrap re-sampling method has been utilized in re-sampling the data in this work. This method has successfully modeled the process as shown in the results.     

Construction costs and physico-chemical properties of the assimilatory organs of Nepenthes species in Northern Borneo

BACKGROUND AND AIMS: Species of the Nepenthaceae family are under-represented in studies of leaf traits and the consequent view of mineral nutrition and limitation in carnivorous plants. This study is aimed to complement existing data on leaf traits of carnivorous plants. METHODS: Physico-chemical properties, including construction costs (CC), of the assimilatory organs (leaf and pitcher) of a guild of lowland Nepenthes species inhabiting heath and/or peat swamp forests of Brunei, Northern Borneo were determined. KEY RESULTS: Stoichiometry analyses indicate that Nepenthes species are nitrogen limited. Most traits vary appreciably across species, but greater variations exist between the assimilatory organs. Organ mass per unit area, dry matter tissue concentration (density), nitrogen (N), phosphorus (P), carbon, heat of combustion (H(c)) and CC values were higher in the leaf relative to the pitcher, while organ thickness, potassium (K) and ash showed the opposite trend. Cross-species correlations indicate that joint rather than individual consideration of the leaf and the pitcher give better predictive relationships between variables, signalling tight coupling and functional interdependence of the two assimilatory organs. Across species, mass-based CC did not vary with N or P, but increases significantly with tissue density, carbon and H(c), and decreases with K and ash contents. Area-based CC gave the same trends (though weaker in strength) in addition to a significant positive correlation with tissue mass per unit area. CONCLUSIONS: The lower CC value for the pitcher is in agreement with the concept of low marginal cost for carnivory relative to conventional autotrophy. The poor explanatory power of N, P or N : P ratio with CC suggests that factors other than production of expensive photosynthetic machinery (which calls for a high N input), including concentrations of lignin, wax/lipids or osmoregulatory ions like K(+), may give a better explanation of the CC variation across Nepenthes species.     

Utilization of seagrass habitats by juvenile groupers and snappers in Banten Bay,Banten Province,Indonesia

Coastal development in Banten Bay, Indonesia, decreased seagrass coverage to only 1.5% of its surface area. We investigated the importance of seagrass as habitat for juvenile groupers (Serranidae) and snappers (Lutjanidae), by performing beam trawl hauls on a weekly basis in two seagrass locations and one mudflat area, and monthly trawl hauls in three different microhabitats (dense, mixed and patchy seagrass) in one of the seagrass locations. We studied the effects of location and microhabitat, as well as temporal patterns (diel, weekly and monthly) on the probability of occurrence and abundance of the most abundant grouper (Orange-spotted grouper, Epinephelus coioides) and snapper (Russell’s snapper, Lutjanus russellii). We found that both species were almost exclusively found in seagrass locations, with a preference for microhabitats of high complexity (dense and mixed microhabitats). L. russellii had a higher probability of catch and abundance during the night, most probably because of its ability to avoid the beam trawl during daytime sampling. In addition there was an effect of week and month on the presence and abundance of both species, but patterns were unclear, probably because of high fishing pressure on juvenile groupers and snappers by push net fishermen. Groupers and snappers mainly fed on abundant shrimps, and to a lesser extent on fish. Moreover, juveniles find protection against predators in seagrass, which confirmed the critical role of quantity and quality of seagrass areas for juvenile groupers and snappers in Banten Bay.     

Estimation of linear and mass attenuation coefficients of soy–lignin bonded Rhizophora spp. particleboard as a potential phantom material using caesium-137 and cobalt-60

In this study, linear and mass attenuation coefficients of fabricated particleboards intended for use as phantom material were estimated using ¹³⁷Cs and ⁶⁰Co radiation sources. Particleboards made of Rhizophora spp. wood trunk bonded with soy flour and lignin were fabricated at a target density of 1.0 g cm^?3, with and without gloss finish coating. Elemental composition of the particleboards was obtained by means of energy dispersive X-ray (EDX) spectroscopy. Experimental setups were simulated via the GATE Monte Carlo (MC) package, with particle histories of 1?×?10⁶–1?×?10⁷. Linear and mass attenuation coefficients obtained from measurements and GATE simulations were compared and discussed. The percentage differences between the measured and simulated linear and mass attenuation coefficients of the samples were reasonably small (2.05–4.88% for ¹³⁷Cs and 3.24–5.38% for ⁶⁰Co). It is shown that all the particleboards have the potential to be used as phantom materials as the attenuation coefficients measured were in good agreement with those of water (calculated with XCOM) and with those simulated with the GATE toolkit. The use of gloss finish coating also did not show any significant effect on the attenuation coefficient of the phantom material. Verification of experimental results via GATE simulations has been shown crucial in providing reliable data for energy transmission studies. Based on the results achieved in this study, it is concluded that the studied material—Rhizophora spp. wood trunk bonded with soy flour and lignin including gloss finish coating—can be used in radiation dosimetry studies.

     

Evolution of Influenza B Virus in Kuala Lumpur,Malaysia, between 1995 and 2008

Influenza B virus causes significant disease but remains understudied in tropical regions. We sequenced 72 influenza B viruses collected in Kuala Lumpur, Malaysia, from 1995 to 2008. The predominant circulating lineage (Victoria or Yamagata) changed every 1 to 3 years, and these shifts were associated with increased incidence of influenza B. We also found poor lineage matches with recommended influenza virus vaccine strains. While most influenza B virus lineages in Malaysia were short-lived, one circulated for 3 to 4 years.     

A fluorescence-based alkaline phosphatase-coupled polymerase assay for identification of inhibitors of dengue virus RNA-dependent RNA polymerase

The flaviviral RNA-dependent RNA polymerase (RdRp) is an attractive drug target. To discover new inhibitors of dengue virus RdRp, the authors have developed a fluorescence-based alkaline phosphatase-coupled polymerase assay (FAPA) for high-throughput screening (HTS). A modified nucleotide analogue (2'-[2-benzothiazoyl]-6'-hydroxybenzothiazole) conjugated adenosine triphosphate (BBT-ATP) and 3'UTR-U(30) RNA were used as substrates. After the polymerase reaction, treatment with alkaline phosphatase liberates the BBT fluorophore from the polymerase reaction by-product, BBT(PPi), which can be detected at excitation and emission wavelengths of 422 and 566 nm, respectively. The assay was evaluated by examining the time dependency, assay reagent effects, reaction kinetics, and signal stability and was validated with 3'dATP and an adenosine-nucleotide triphosphate inhibitor, giving IC(50) values of 0.13 μM and 0.01 μM, respectively. A pilot screen of a diverse compound library of 40,572 compounds at 20 μM demonstrated good performance with an average Z factor of 0.81. The versatility and robustness of FAPA were evaluated with another substrate system, BBT-GTP paired with 3'UTR-C(30) RNA. The FAPA method presented here can be readily adapted for other nucleotide-dependent enzymes that generate PPi.     

A two-step acid-catalyzed process for the production of biodiesel from rice bran oil

A study was undertaken to examine the effect of temperature, moisture and storage time on the accumulation of free fatty acid in the rice bran. Rice bran stored at room temperature showed that most triacylglyceride was hydrolyzed and free fatty acid (FFA) content was raised up to 76% in six months. A two-step acid-catalyzed methanolysis process was employed for the efficient conversion of rice bran oil into fatty acid methyl ester (FAME). The first step was carried out at 60 degrees C. Depending on the initial FFA content of oil, 55-90% FAME content in the reaction product was obtained. More than 98% FFA and less than 35% of TG were reacted in 2 h. The organic phase of the first step reaction product was used as the substrate for a second acid-catalyzed methanolysis at 100 degrees C. By this two-step methanolysis reaction, more than 98% FAME in the product can be obtained in less than 8 h. Distillation of reaction product gave 99.8% FAME (biodiesel) with recovery of more than 96%. The residue contains enriched nutraceuticals such as gamma-oryzanol (16-18%), mixture of phytosterol, tocol and steryl ester (19-21%).