Optimisation of oxygen delignification in production of totally chlorine-free cellulose pulps from oil palm empty fruit bunch fibre

The effects of oxygen delignification on prehydrolysed-soda pulps produced from oil palm (Elaeis guineensis) empty fruit bunch fibre were statistically investigated by employing response surface methodology (RSM). Polynomial estimation models of five response variables namely yield, Kappa number, α-cellulose, viscosity and brightness were developed, each model comprised of four-independent variables: reaction temperature, reaction time, the alkali charge, and initial Kappa number. The calculated optimum condition (95 °C reaction temperature, 60 min reaction time, 2% alkali charge, and initial Kappa number of 6.6) is capable to produce pulp with 98.1% yield, Kappa number 2.4, 97.38% α-cellulose, pulp viscosity 13.8 cPs and ISO brightness 67.1%, which were proven close to the predicted values calculated from estimation models. The results indicated that oxygen delignification which is used as the first stage of bleaching sequence has the ability to both delignify and increase pulp brightness without substantial reduction in viscosity and α-cellulose, that appeared to be beneficial for subsequent TCF bleaching.     

Influence of pulping variables on the properties of Elaeis guineensis soda pulp as evaluated by response surface methodology

Response surface methodology with central composite design was used to investigate the influence of pulping conditions, viz. cooking temperature, time-at-temperature and alkali charge for alkaline pulping of oil palm empty fruit bunch fibres, on the properties of the pulp and paper obtained (screened yield, Kappa number, tensile and tear indices). Quadratic models consisting of the three independent variables were found to accurately describe the pulping of this material with correlation between the actual and predicted values of the response variables having a relatively good degree of R². The delignification of oil palm empty fruit bunch fibre can be achieved with ease using sodium hydroxide as the sole cooking agent to about 30–45% yield with the process greatly enhanced by an increase in temperature. Although, a relatively low temperature (about 160°C) within the limits of pulping time (60–120 min) and of alkali charge between 20 and 30% is generally sufficient.     

Evaluation of semen collected by electroejaculation from captive lesser Malay chevrotain (Tragulus javanicus).

Thirteen sexually mature captive male lesser Malay chevrotains (Tragulus javanicus) were each anesthetized twice with tiletamine-zolazepam for electroejaculation. Viable spermatozoa were collected from all animals. The semen was creamy, milky, pale yellowish, or watery. The mean values for ejaculate volume, sperm concentration, and percentages of sperm motility, normality and viability were 23.7 +/- 2.5 microl, 366.9 +/- 127.8 x 10(6) spermatozoa/ml, 40.0% +/- 3.1%, 71.4% +/- 1.6%, and 59.6% +/- 2.1%, respectively. Semen pH was 7-8. No adverse effects of electroejaculation were noted. These are the first reported values for semen of lesser Malay chevrotain. Electroejaculation should be usable for routine semen collection in this species.     

Gene flow from transgenic wheat and barley under field conditions

In this study the frequency and distance of gene flow from transgenic wheat (Triticum aestivum) and barley (Hordeum vulgare) to non-transgenic wheat and barley crops was investigated under local field conditions. Trials were conducted in the Australian Capital Territory (ACT) and in South Australia (SA). Gene flow from transgenic wheat was confirmed at frequencies of 0.012% and 0.0037% in the ACT and SA, respectively. In both trials gene flow occurred over distances of less than 12 m. Gene flow was also detected from transgenic barley at a frequency of 0.005%, over a distance of less than 12 m. The results show that under Australian field conditions, gene flow occurs at extremely low frequencies and over very short distances. Physical separation of transgenic and non-transgenic cereal crops by greater than 12 m should ensure that contamination of adjacent non-transgenic cereal crops remains less than 0.02%, well below the level permitted under Australian regulations.     

Evaluation of morpho-physiological traits of MRQ74 pyramided lines with drought yield QTLs

Drought regularly affects rainfed lowland and upland rice ecosystems in Malaysia. Three drought yield QTLs, viz qDTY _2.2 , qDTY _3.1 and qDTY _12.1 successfully pyramided into MRQ74 to increase its yield under reproductive stage drought stress (RS). Forty-eight genotypes comprising 39 pyramided lines (PLs) with different qDTYs combinations, four parents including MRQ74 (recipient) and five checks were evaluated for morpho-physiological traits under RS and non-stress (NS). This study aims to determine which traits influenced by individual qDTY and qDTY combinations and to gain better understanding of QTL interactions in enhancing grain yield (GY) under RS. Results showed plant height, number of panicles, root length, root weight, relative water content and 100-grain weight increased while chlorophyll content and GY decreased under RS compared to NS. No significant difference was observed in days to flowering, leaf rolling and grain length between selected PLs and MRQ74 under RS. Six PLs with yield advantage (YA) of 208.17–1751.63 kg ha^?1 compared to MRQ74 in RS but yielded similar to MRQ74 under NS were further selected. Under RS, qDTY class analysis showed qDTY _12.1 individually and combination qDTY _12.1  + ?qDTY _2.2 produced the highest yield of 1521.77 and 1092.30 kg ha^?1 respectively. qDTY _12.1 as single or combination with other qDTY is the best qDTY in stabilizing GY under RS. PL-77 with qDTY _12.1 is the best PL with YA of more than 1100 kg ha^?1 compared to MRQ74 in both RS and NS conditions can be recommended for cultivation in normal and drought-prone areas.     

Single, rapid coastal settlement of Asia revealed by analysis of complete mitochondrial genomes

A recent dispersal of modern humans out of Africa is now widely accepted, but the routes taken across Eurasia are still disputed. We show that mitochondrial DNA variation in isolated "relict" populations in southeast Asia supports the view that there was only a single dispersal from Africa, most likely via a southern coastal route, through India and onward into southeast Asia and Australasia. There was an early offshoot, leading ultimately to the settlement of the Near East and Europe, but the main dispersal from India to Australia approximately 65,000 years ago was rapid, most likely taking only a few thousand years.     

Robust transformation procedure for the production of transgenic farmer-preferred cassava landraces

ABSTRACT: Recent progress in cassava transformation has allowed the robust production of transgenic cassava even under suboptimal plant tissue culture conditions. The transformation protocol has so far been used mostly for the cassava model cultivar 60444 because of its good regeneration capacity of embryogenic tissues. However, for deployment and adoption of transgenic cassava in the field it is important to develop robust transformation methods for farmer- and industry-preferred landraces and cultivars. Because dynamics of multiplication and regeneration of embryogenic tissues differ between cassava genotypes, it was necessary to adapt the efficient cv. 60444 transformation protocol to genotypes that are more recalcitrant to transformation. Here we demonstrate that an improved cassava transformation protocol for cv. 60444 could be successfully modified for production of transgenic farmer-preferred cassava landraces. The modified transformation method reports on procedures for optimization and is likely transferable to other cassava genotypes reportedly recalcitrant to transformation provided production of high quality FEC. Because the three farmer-preferred cassava landraces selected in this study have been identified as resistant or tolerant to cassava mosaic disease (CMD), the adapted protocol will be essential to mobilize improved traits into cassava genotypes suitable for regions where CMD limits production.