Three saponins from Oxytropis species.

Three flavonoids and three saponins have been isolated from Oxytropis species. Their structures were determined as isorhamnetin-3-O-beta-D-glucoside, rhamnetin-3-O-beta-D-galactoside, apigenin, 3-O-[alpha-L-rhamnopyranosyl (1----2)-beta-D-glucopyranosyl(1----4)-beta-D-glucuronopyranosyl]+ ++soyasapogenol B, 3-O-[beta-D-glucopyranosyl(1----2)-beta-D-glucuronopyranosyl] azukisapogenol and a new saponin 3-O-[beta-D-glucopyranosyl(1----2)-beta-D-glucopyranosyl]-25-O-alpha-L- rhamnopyranosyl-(20S,24S)-3 beta,16 beta, 20,24,25-pentahydroxy-9,19-cycloanostane.     

Development and use of striped bass-specific RFLP probes

We sought to develop nuclear DNA (nDNA) probes which could be used to complement mtDNA and DNA fingerprinting markers in distinguishing striped bass, Morone saxatilis (Walbaum), from discrete spawning systems. Restriction endonuclease-generated single copy, 10–20-kb striped bass nuclear nDNA fragments were cloned into the bacteriophage vector Lambda Dash II and tested in Southern blot analyses for their abilities to reveal population-specific polymorphisms. Three of the I7 nDNA sequences tested exhibited polymorphisms which potentially could be used to delineate striped bass populations. One probe, DSB 22, revealed significant genotypic frequency differences between Gulf of Mexico and Atlantic striped bass and among striped bass representative of some Atlantic systems. These preliminary results suggest that single copy nDNA sequences may provide sufficient polymorphisms to aid in stock identification of species which proved genetically monomorphic using other approaches.     

Interaction of the release factors with the Escherichia coli ribosome: structurally and functionally-important domains.

There are two major domains of interaction between the Escherichia coli release factors (RF-1 and RF-2) and each subunit of the ribosome. RF-2 has a binding domain on the shoulder and lower head region of the small subunit at the small lobe distant from the decoding site. This is in close proximity to one of the domains on the large subunit which includes the body dimer of L7/L12 and L11. The other domains of interaction, at the decoding site on the small subunit, and at the peptidyltransferase centre of the large subunit of the ribosome, are some distance from the first two, although the evidence for direct contact with the ribosome is less comprehensive. The release factors may therefore have two distinct structural domains, and in support of this concept RF-1 and RF-2 can both be cleaved into two fragments by papain. Region-specific antibodies, and antibodies against defined peptide within the RF sequences have given an indication that a significant part of an interacting RF molecule is in close proximity to the ribosome surface, confirming an observation by immunoelectron microscopy which suggested that the RF penetrates deeply into the cleft between the two subunits. A region of highly conserved primary sequence between the two release factors from E coli is also conserved in those from B subtilis suggesting it forms an important structural or functional domain. Antibodies against peptides from the N-terminal end of this region strongly inhibit binding of the RF to the ribosome.     

Alterations of auxin perception in rolB-transformed tobacco protoplasts. Time course of rolB mRNA expression and increase in auxin sensitivity reveal multiple control by auxin.

Expression and physiological effects of the root-inducing rolB gene of Agrobacterium rhizogenes T-DNA were studied simultaneously in tobacco (Nicotiana tabacum) mesophyll protoplasts. The kinetic study of the expression of rolB mRNA following exogenous auxin application showed that auxin transiently stimulated rolB expression, with mRNA levels starting to accumulate 6 to 9 h after auxin was supplied and increasing 300-fold after 12 to 18 h. The parallel study of the auxin sensitivity of rolB-transformed protoplasts, as assayed by their electrical response to the hormone, showed that the auxin treatment generated an increase in sensitivity by a factor of up to 100,000, whereas in untransformed protoplasts the same auxin treatment induced an increase in auxin sensitivity that never exceeded 30- to 50-fold. This reflects a strong cooperative effect of auxin and rolB in transformed protoplasts. Surprisingly, the maximal increase in sensitivity was observed several hours before the maximal accumulation of rolB mRNA, suggesting that the dramatic control of auxin sensitivity by auxin in rolB-transformed protoplasts requires only low levels of rolB expression. Antibodies directed against ZmER-abp1, the major auxin-binding protein from maize, differentially altered the auxin sensitivity of the electrical response of rolB-transformed and normal protoplasts. This suggests that alterations of the auxin reception-transduction pathway at the plasma membrane of rolB-transformed protoplasts may account for their increased auxin sensitivity.     

Linkage of bovine erythrocyte antigen loci B, C, L, S, Z, R' and T' and the serum protein loci post-transferrin 2 (PTF 2), vitamin D binding protein (GC) and albumin (ALB) to DNA microsatellite markers

Seven bovine erythrocyte antigen loci and three serum protein loci were tentatively assigned to chromosomes or synteny groups by linkage analysis to previously assigned microsatellite DNA markers. The erythrocyte antigen locus EAB was mapped to synteny group U27; EAC to chromosome 18, synteny group U9; EAL to chromosome 3, synteny group U6; EAS to chromosome 21, synteny group U4; EAZ to chromosome 10, synteny group U5; EAR' to chromosome 16, synteny group U1; and EAT' to chromosome 19, synteny group U21. The vitamin D binding protein (GC) and albumin (ALB) loci were assigned to chromosome 6, synteny group U15 and post-transferrin 2 (PTF 2) to chromosome 19, synteny group U21.     

Integrating the porcine physical and linkage map using cosmid-derived markers

An essential part in the development of informative linkage maps is to include genetic markers that have been anchored by physical mapping. Here a set of 18 porcine cosmid-derived genetic markers are reported that have been mapped by linkge analysis, and that also have been physically localized by fluorescence in situ hybridization (FISH). Three different strategies were used to establish polymorphic markers from the cosmid clones. Firstly, dinucleotide microsatellite loci were derived by sequencing cosmid subclones containing (CA), repeats. Secondly, variable SINE 3′ poly(A) tracts (SINEVA) were identified by direct SINE-PCR amplification of cosmid clones. Thirdly, the cosmids were used in Southern blot hybridization to detect restriction fragment length polymorphisms (RFLPs). Compared with the most recent consensus compilation of the porcine gene map, the present assignment of markers to chromosomes Zp, 3, 4, 10, 12q, and 16 represents the first loci mapped to these chromosomes, for which linkage as well as in situ data are now available.     

Conservation of two predator species for biological control ofChrysophtharta bimaculata (Col.: Chrysomelidae) in tasmanian forests

Chrysophtharta bimaculata (Olivier) (Coleoptera: Chrysomelidae) is a major defoliator of regeneration eucalypt trees in Tasmania causing a significant reduction in height and diameter increment of trees which reduces wood volume per hectare. A study to conserve and enhance the efficiency of coccinellid species chieflyCleobora mellyi (Mulsant) (Coleoptera: Coccinellidae), and the cantharid,Chauliognathus pulchellus (Macleay) (Coleoptera: Cantharidae), for the biological control ofC. bimaculata was conducted in young regeneration forests in southern Tasmania from 1991–92. Cantharid adults and coccinellid adults and larvae feed onC. bimaculata eggs and, to a lesser extent, young larvae. The study found that coccinellids were more active throughout the egg and early (1^st and 2^nd) stage ofC. bimaculata. The cantharid, however was active only during the egg stage of the prey and then disappeared from the plantation. The coccinellids were therefore the most useful predators, but their population declined when the prey reached the 3^rd and 4^th stages. As shortage of food may account for this decline, supplementary food was provided in the form of sucrose sprays or sugar granules at a feeding station. This resulted in the retention of both predators and particularly the coccinellids and enhanced their efficacy.