Protein relationships between natural populations ofUlex europaeus andU. gallii (Faboideae,Genisteae) and their hybrids

Prostrate ecotypes ofUlex gallii, an atlantic species with autumnal flowering, grow on capes in Brittany (France).U. europaeus, a widespread species, has winter and spring flowering, but some plants can precociously flower in autumn, so that hybridization can be possible between these two species in areas where their ranges overlap. By using different isoenzyme systems and crossed immunoelectrophoresis obtained with seed proteins, it is possible to consider plants with intermediate morphological characters betweenU. gallii andU. europaeus as natural hybrids.     

中国海菜花属植物三种同工酶的酶谱式样及其系统学含义

本文研究了代表中国海菜花属全部已知分类群的18个野生居群的过氧化物酶同工酶(POX),和其中7个居群的细胞色素氧化酶同工酶(COX),3个居群的酯酶同工酶酶谱式样及其系统学含义。结果表明:所有分类群的POX酶谱和龙舌草的COX酶谱均具多形现象,暗示编码有关同工酶的基因在种内居群间存在差异;3种同工酶都具分类价值,其分类结果与形态学分类结果一致支持将出水水菜花归并到水菜花中,取消海菜花的两个变种——路南海菜花和通海海菜花,而仅保留变种波叶海菜花。此外,本文初步揭示了POX酶谱式样与繁育系统的相关性。     

Enzyme diversity in pearl millet (Pennisetum glaucum)

Summary The survey of enzyme polymorphism in West African pearl millet cultivars reported by Tostain et al. 1987 has been extended to include populations from other regions of Africa and from India. The eight enzyme systems studied included: alcohol dehydrogenase, -esterase, catalase, phosphoglucoisomerase, phosphoglucomutase, 6-phosphogluconate dehydrogenase, glutamate oxaloacetate transaminase, and malate dehydrogenase. One-hundred-ninety-nine populations of millet were analyzed, including 74 populations studied earlier. No new enzyme diversity was observed. Intrapopulation diversity ranged from 70%–90% of the total diversity, depending on their regions of origin. Four principal groups were distinguished in the following decreasing order of diversity: early-maturing cultivars from West and East Africa, late — maturing cultivars from West and East Africa, cultivars from India, and cultivars from southern Africa. The early-maturing cultivars were distributed between two principal focal points from East Africa in the East to Mali in the West. In the center were found millets from Niger which were most diverse. Indian and southern African cultivars were distinct, with the former appearing relatively similar to those of Niger, and the latter somewhat similar to late-maturing cultivars from West Africa, a diverse group that included late-maturing cultivars from East Africa. Based on the results obtained, an evolutionary hypothesis proposed here includes: multiple domestications in the Sahel, creation of early-maturing cultivars and their migration eastwards to India plus a southwards migration to Sudanian zone, and creation of late-maturing cultivars and their migration simultaneously westwards, eastwards, and southwards to southern Africa.     

Parallel evolution of pairs of dehydrogenase isoenzymes

Summary Lactate dehydrogenase and glycerol 3-phosphate dehydrogenase are metabolically coupled by the anaerobic dismutation of glyceraldehyde 3-phosphate and by the NAD redox state. This causes the concentrations of lactate and glycerol 3-phosphate to accumulate proportionally during anaerobic muscle contraction; these concentrations are high relative to those in aerobic tissues such as liver. We show that the isoenzymes of lactate dehydrogenase and glycerol 3-phosphate dehydrogenase from chicken breast muscle haveKm values for lactate and glycerol 3-phosphate, respectively, that are 10-fold higher than theKm values measured for the lactate dehydrogenase and glycerol 3-phosphate dehydrogenase isoenzymes from chicken liver. The association of proportionally higherKm values with the potential for proportionally higher accumulation of substrates suggests that the isoenzymes of lactate dehydrogenase and glycerol 3-phosphate dehydrogenase from chicken muscle have evolved in parallel as a coupled metabolic unit distinct from the coupled isoenzymes in liver. The parallelism observed for the reduced substrates extends to the oxidized substrates, and to the coenzymes, NAD⁺ and NADH.     

Adaptive rather than non-adaptive evolution of Mimulus guttatus in its invasive range

Adaptive and non-adaptive evolutionary processes are likely to play important roles in biological invasions but their relative importance has hardly ever been quantified. Moreover, although genetic differences between populations in their native versus invasive ranges may simply reflect different positions along a genetic latitudinal cline, this has rarely been controlled for. To study non-adaptive evolutionary processes in invasion of Mimulus guttatus, we used allozyme analyses on offspring of seven native populations from western North America, and three and four invasive populations from Scotland and New Zealand, respectively. To study quantitative genetic differentiation, we grew 2474 plants representing 17 native populations and the seven invasive populations in a common greenhouse environment under temporarily and permanently wet soil conditions. The absence of allozyme differentiation between the invasive and native range indicates that multiple genotypes had been introduced to Scotland and New Zealand, and suggests that founder effects and genetic drift played small, if any, roles in shaping genetic structure of invasive M. guttatus populations. Plants from the invasive and native range did not differ in phenology, floral traits and sexual and vegetative reproduction, and also not in plastic responses to the watering treatments. However, plants from the invasive range produced twice as many flower-bearing upright side branches than the ones from the native populations. Further, with increasing latitude of collection, vegetative reproduction of our experimental plants increased while sexual reproduction decreased. Plants from the invasive and native range shared these latitudinal clines. Because allozymes showed that the relatedness between native and invasive populations did not depend on latitude, this suggests that plants in the invasive regions have adapted to the local latitude. Overall, our study indicates that quantitative genetic variation of M. guttatus in its two invasive regions is shaped by adaptive evolutionary processes rather than by non-adaptive ones.     

不同无机盐对柱胞鱼腥藻同工酶的影响

盐胁迫对蓝藻的影响已有广泛的研究,人们围绕着渗透胁迫(osmoticstress),研究了高浓度盐影响蓝藻的生长、光合作用、呼吸作用、固氮作用、蛋白质和RNA的合成等〔1～4〕;但迄今为止,尚未见到有关盐胁迫下蓝藻同工酶变化情况的报道。无机盐对同工酶影响无论对于盐胁迫反应生理及机制的研究,还是对于蓝藻基因表达调控等都有重要的意义。为此,我们在研究了无机盐对蓝藻的细胞学效应、固氮酶活性的影响〔5～7〕等之后,就无机盐对蓝藻同工酶的影响进行了初步研究。1　材料与方法试验用的柱胞鱼腥藻(Anabaenacylindrica)是一种具异形胞的丝状固氮…     

Hydrophobic interaction chromatography and capillary zone electrophoresis to explore the correlation between the isoenzymes of salivary α-amylase and dental caries

High-performance hydrophobic interaction chromatography (HIC) and capillary zone electrophoresis (CZE) were utilized in an effort to find the correlation between the composition of some isoenzymes of human salivary α-amylase (HSA) and dental caries. The mixture of more than three isoenzymes of HSA, fractionated from human parotid saliva with HIC, was further separated by CZE at the optimum pH 6.50. The composition and relative quantity of these isoenzymes were compared between two groups of individuals with different caries-susceptibility. It is found that the present frequency of peak II on CZE in the caries-free group was higher than that in the caries-active group and the relative quantities of peak III and peak IV showed remarkable differences (p<0.05) between the two groups. These results may indicate that the composition of HSA isoenzymes is related to the occurrence of dental caries. However, more work should be done to further affirm this correlation between the isoenzymes of salivary α-amylase and dental caries.     

Danish Rhizobium leguminosarum strains nodulating 'Afghanistan' pea (Pisum sativum)

A wild pea ( Pisum sativum L.) native to Afghanistan normally known to be resistant to nodulation with European strains of Rhizobium leguminosarum was nodulated early and effectively in field soil in Denmark. Isolates from nodules formed effective nodules abundantly on 'Afghanistan' on reinfection under aseptic conditions. Five types differing in isoenzyme composition pattern were found among 15 isolates from 'Afghanistan' nodules. None were identical with the 'Tom' strain from Turkey, which also forms effective nodules with 'Afghanistan'. The five types were also different with respect to isoenzyme pattern from Rhizobium leguminosarum strains isolated from a modern pea variety cultivated in the same field.     

Identification of pig liver esterase variants by tandem mass spectroscopy analysis and their characterization

Pig liver esterase (PLE) is probably the most important carboxyl esterase in organic synthesis and is commercially obtained by extraction of the animal tissue. However, problems occur in its application due to the presence of several isoenzymes (α-, β- and γ-PLE). The functional expression of the γ-isoenzyme was already shown and differences in the enantioselectivity compared to the commercial preparations were confirmed. The amino acid and nucleotide sequences of the α- and β-PLE are still unknown. In this work, putative sequences of the α-isoenzyme were identified from a commercial PLE preparation by 2D gel electrophoresis, digestion with proteases and analysis using Matrix-assisted laser desorption/ionization–time of flight (TOF) and electrospray ionisation quadrupole–TOF mass spectrometry. Based on these results, three amino acid exchanges were introduced into the gene encoding γ-rPLE by site-directed mutagenesis, and the proteins were expressed in E. coli Origami (DE3). The produced PLE mutants were characterised with respect to their substrate specificity and enantioselectivity. No significant differences in the activity towards methyl butyrate were found, but several variants showed substantially enhanced enantioselectivity in the resolution of (R,S)-1-phenyl-2-butyl acetate with E = 100 for the best mutant V236P/A237G.