Methylation levels of a novel genetic element, EgNB3 as a candidate biomarker associated with the embryogenic competency of oil palm

The association between DNA methylation status and embryogenic competency in oil palm tissue culture was examined through Representational Difference Analysis (RDA) approach, using methylation-sensitive restriction endonucleases. “Difference Products” (DPs) of RDA derived from palms of similar genetic backgrounds but exhibiting different embryogenesis rates during the regeneration process were isolated. The DPs were sequenced using a pyrosequencing platform. To our knowledge, this is the first study profiling partial HpaII methylation sites in oil palm young leaf tissues which are potentially associated with embryogenic amenability through a genomic subtractive approach. Quantitative real-time PCR analysis demonstrated that the methylation status of a novel fragment, EgNB3, was higher in highly embryogenic leaf explants compared to low embryogenesis rate materials. These differences are likely to be contributed by the 5′-^mCCGG-3′ and/or 5′-^mC^mCGG-3′ methylation patterns. Our data suggest that the differentially methylated site in EgNB3 has potential as a molecular biomarker for the screening of oil palm leaf explants for their embryogenic potentials.     

Evidence for an endothelial cell-derived factor which stimulates the growth of human peripheral blood mononuclear cells

Evidence is provided which demonstrates that conditioned media of cultured endothelial cells derived from human umbilical veins contained a factor which stimulated peripheral blood mononuclear cell [3H]thymidine uptake. A dose-dependent response in peripheral blood mononuclear cell [3H]thymidine uptake was obtained when cells were incubated with increasing concentrations of supernatant of endothelial cell cultures. Studies on temporal kinetics demonstrated that stimulatory activity was evident when mononuclear cells had been incubated with endothelial cell supernatant for 120 hr or more. Preliminary characterization showed the growth immunoregulatory factor to have a molecular weight greater than 100,000 Da.     

Enzyme polymorphism in Mansonia uniformis, a mosquito vector of brugian filariasis

Three temporal samples of a wild population of Mansonia uniformis were analysed for genetic variation at six gene-enzyme systems. Adenylate kinase, hexokinase (3 loci) and cathodal malate dehydrogenase were monomorphic. Phosphoglucomutase, glucose phosphate isomerase, isocitrate dehydrogenase and anodal malate dehydrogenase were polymorphic. Each of the polymorphic loci was represented by three alleles. The average heterozygosity or gene diversity was 0.0437.     

Rotavirus electropherotypes in Malaysian children.

A 12-month study was carried out on the molecular epidemiology of rotavirus in urban and suburban Malaysian children. Analysis of faecal samples from 973 hospitalized diarrhoeic children by polyacrylamide gel electrophoresis detected 268 rotaviruses (28%). All isolates were group A rotaviruses, which produced 22 electropherotypes: 16 (91.5%) with long RNA migration patterns and 6 (8.5%) with short patterns. One of the long-pattern electropherotypes was the predominant strain (71.1% of the total electropherotypes) isolated during this study. Although 3 other strains were detected sporadically over the study period, 16 others were present only during the first 7 months and 2 others were confined to the last 5 months. Long- and short-pattern electropherotypes were found to co-circulate extensively. There was a significant association of short-pattern electropherotypes with infection in older children. In addition, the prevalence of vomiting and mean duration of diarrhoea were significantly associated with different electropherotypes.     

Sodium counterion activity of poly(S-carboxymethyl-L-cysteine) and the beta–random-coil transition

Sodium ion activity was measured using a Na-glass electrode in a solution of poly(S-carboxymethyl-L -cysteine) with no added salt at various degrees of neutralization and various concentrations for samples of different molecular weights. The conformational change from random coil to the β-structure was detected from the activity coefficient of counterions, as well as from CD. At a constant degree of neutralization, the activity coefficient is insensitive to a concentration change not only in the random-coil state, but also in the range of conformational change if the concentration is below about 3 × 10^?2 monomolal. At high concentrations of about 5 × 10^?2 monomolal, however, the activity coefficient becomes low, probably due to the occurrence of the stacking of the pleated sheets.