Gene expression in Eucalyptus branch wood with marked variation in cellulose microfibril orientation and lacking G-layers

In response to gravitational stresses, angiosperm trees form tension wood in the upper sides of branches and leaning stems in which cellulose content is higher, microfibrils are typically aligned closely with the fibre axis and the fibres often have a thick inner gelatinous cell wall layer (G-layer). Gene expression was studied in Eucalyptus nitens branches oriented at 45 degrees using microarrays containing 4900 xylem cDNAs, and wood fibre characteristics revealed by X-ray diffraction, chemical and histochemical methods. Xylem fibres in tension wood (upper branch) had a low microfibril angle, contained few fibres with G-layers and had higher cellulose and decreased Klason lignin compared with lower branch wood. Expression of two closely related fasciclin-like arabinogalactan proteins and a beta-tubulin was inversely correlated with microfibril angle in upper and lower xylem from branches. Structural and chemical modifications throughout the secondary cell walls of fibres sufficient to resist tension forces in branches can occur in the absence of G-layer enriched fibres and some important genes involved in responses to gravitational stress in eucalypt xylem are identified.     

Processing of a membrane protein required for cell-to-cell signaling during endospore formation in Bacillus subtilis

Activation of the late prespore-specific RNA polymerase sigma factor sigma(G) during Bacillus subtilis sporulation coincides with completion of the engulfment process, when the prespore becomes a protoplast fully surrounded by the mother cell cytoplasm and separated from it by a double membrane system. Activation of sigma(G) also requires expression of spoIIIJ, coding for a membrane protein translocase of the YidC/Oxa1p/Alb3 family, and of the mother cell-specific spoIIIA operon. Here we present genetic and biochemical evidence indicating that SpoIIIAE, the product of one of the spoIIIA cistrons, and SpoIIIJ interact in the membrane, thereby linking the function of the spoIIIJ and spoIIIA loci in the activation of sigma(G). We also show that SpoIIIAE has a functional Sec-type signal peptide, which is cleaved during sporulation. Furthermore, mutations that reduce or eliminate processing of the SpoIIIAE signal peptide arrest sporulation following engulfment completion and prevent activation of sigma(G). SpoIIIJ-type proteins can function in cooperation with or independently of the Sec system. In one model, SpoIIIJ interacts with SpoIIIAE in the context of the Sec translocon to promote its correct localization and/or topology in the membrane, so that it can signal the activation of sigma(G) following engulfment completion.     

No association between Angiotensin Converting Enzyme (ACE) gene variation and endurance athlete status in Kenyans

East African runners are continually successful in international distance running. The extent to which genetic factors influence this phenomenon is unknown. The insertion (I) rather than deletion (D) of a 287 bp fragment in the human angiotensin converting enzyme (ACE) gene is associated with lower circulating and tissue ACE activity and with endurance performance amongst Caucasians. To assess the association between ACE gene variation and elite endurance athlete status in an African population successful in distance running, DNA samples were obtained from 221 national Kenyan athletes (N), 70 international Kenyan athletes (I), and 85 members of the general Kenyan population (C). Blood samples were obtained from C and assayed for circulating ACE activity. ACE I/D (rs????--from NCBI SNPdb first time poly mentioned) genotype was determined, as was genotype at A22982GD (rs????--from NCBI SNPdb first time poly mentioned) which has been shown to associate more closely with ACE levels in African subjects than the I/D polymorphism. ACE I/D and A22982G genotypes explained 13 and 24% of variation in circulating ACE activity levels (P = 0.034 and <0.001 respectively). I/D genotype was not associated with elite endurance athlete status (df = 4, chi(2) = 4.1, P=0.39). In addition, genotype at 22982 was not associated with elite endurance athlete status (df = 4, chi(2) = 5.7, P = 0.23). Nor was the A allele at 22982, which is associated with lower ACE activity, more prevalent in N (0.52) or I (0.41) relative to C (0.53). We conclude that ACE I/D and A22982G polymorphisms are not strongly associated with elite endurance athlete status amongst Kenyans.     

湖北省三品种猪27个微卫星座位的遗传变异

采用国际动物遗传学会（ISAG）和联合国粮农组织（FAO）共同推荐的27个微卫星标记,对湖北省3个主要地方猪种（通城猪、清平猪和阳新猪）的遗传变异进行了检测。计算出各个品种的基因杂合度、各个座位的多态信息含量及品种间的遗传距离。结果表明,3个地方猪种的平均基因杂合度分别为0.7489、0.6987和0.6273,遗传多样性比较丰富;通城猪和清平猪亲缘关系较近,而两者与阳新猪亲缘关系略远。     

A genetic linkage map for Pinus radiata based on RFLP, RAPD, and microsatellite markers

A genetic linkage map for radiata pine (Pinus radiata D. Don) has been constructed using segregation data from a three-generation outbred pedigree. A total of 208 loci were analyzed including 165 restriction fragment length polymorphism (RFLP), 41 random amplified polymorphic DNA (RAPD) and 2 microsatellite markers. The markers were assembled into 22 linkage groups of 2 or more loci and covered a total distance of 1382 cM. Thirteen loci were unlinked to any other marker. Of the RFLP loci that were mapped, 93 were detected by loblolly pine (P. taeda L.) cDNA probes that had been previously mapped or evaluated in that species. The remaining 72 RFLP loci were detected by radiata pine probes from a PstI genomic DNA library. Two hundred and eighty RAPD primers were evaluated, and 41 loci which were segregating in a 11 ratio were mapped. Two microsatellite markers were also placed on the map. This map and the markers derived from it will have wide applicability to genetic studies in P. radiata and other pine species.     

Sub-typing of animal and human Campylobacter spp. using RAPD

R.H. MADDEN, L. MORAN AND P. SCATES. 1996. Based on a 10-mer primer (5'- CCTGTTAGCC-3'), a random amplified polymorphic DNA (RAPD) method for typing Campylobacter coli isolated from pigs was developed. The method proved effective with a high discrimination and good reproducibility. In contrast with serotyping no untypable strains were found out of a total of 269 isolates (veterinary, food and clinical) examined. The method was also successfully applied to typing Campylobacter jejuni from a similar range of sources.