Introduction of 5'-terminal functional groups into synthetic oligonucleotides for selective immobilization

Oligodeoxyribonucleotides terminating in a 5'-primary amine group are synthesized using solid-phase supported phosphoramidite chemistry. The 5'-terminal amine group in the deprotected oligomers is further derivatized with either succinic anhydride to give 5'-carboxylic acid or with dithiobis(succinimidylpropionate) followed by treatment with dithioerythritol to produce 5'-thiol-terminated oligonucleotides. The 5'-thiol-terminated oligonucleotides are selectively immobilized on solid supports containing either p-chloromercuribenzoate or 2,2'-dithiobis(5-nitropyridine) activated thiol groups.     

Determination of impurities in nucleoside 3'-phosphoramidites by fast atom bombardment mass spectrometry

Negative-ion fast atom bombardment mass spectrometry is quite useful for the identification of products and by-products formed during the synthesis of nucleoside 3'-phosphoramidites. The data show that detritylation and oxidation are side reactions which occur during the synthesis of monomeric units used in the construction of oligodeoxyribonucleotides by the phosphite triester method.     

Spartina alterniflora loisel root structure and meiofaunal abundance

Meiofauna were collected from adjacent areas with and without Spartina alterniflora Loisel culms. Environmental complexity resulting from root structure cannot be determined by simply observing S. alterniflora culm distribution. There were no significant differences between the two areas with respect to root density or root sizes; however, the number of live roots was significantly higher in the area containing Spartina culms. Nematodes, the most abundant taxon were positively correlated with live root density. In contrast, the number of dead roots and harpacticoid copepods were higher in the area without culms. This study suggests that nematodes are positively associated with micro-oxygenated zones produced by live S. alterniflora roots. Other measures of biogenic structure, such as total root density or root size fractions are not important in affecting nematode abundance.