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BACKGROUND AND AIMS: Despite the great importance of autopolyploidy in the evolution of angiosperms, relatively little attention has been devoted to autopolyploids in natural polyploid systems. Several hypotheses have been proposed to explain why autopolyploids are so common and successful, for example increased genetic diversity and heterozygosity and the transition towards selfing. However, case studies on patterns of genetic diversity and on mating systems in autopolyploids are scarce. In this study allozymes were employed to investigate the origin, population genetic diversity and mating system in the contact zone between diploid and assumed autotetraploid cytotypes of Vicia cracca in Central Europe. METHODS: Four enzyme systems resolved in six putative loci were investigated in ten diploid, ten tetraploid and five mixed-ploidy populations. Genetic diversity and heterozygosity, partitioning of genetic diversity among populations and cytotypes, spatial genetic structure and fixed heterozygosity were analysed. These studies were supplemented by a pollination experiment and meiotic chromosome observation. KEY RESULTS AND CONCLUSIONS: Weak evidence of fixed heterozygosity, a low proportion of unique alleles and genetic variation between cytotypes similar to the variation among populations within cytotypes supported the autopolyploid origin of tetraploids, although no multivalent formation was observed. Tetraploids possessed more alleles than diploids and showed higher observed zygotic heterozygosity than diploids, but the observed gametic heterozygosity was similar to the value observed in diploids and smaller than expected under panmixis. Values of the inbreeding coefficient and differentiation among populations (ρST) suggested that the breeding system in both cytotypes of V. cracca is mixed mating with prevailing outcrossing. The reduction in seed production of tetraploids after selfing was less than that in diploids. An absence of correlation between genetic and geographic distances and high differentiation among neighbouring tetraploid populations supports the secondary contact hypothesis with tetraploids of several independent origins in Central Europe. Nevertheless, the possibility of a recent in situ origin of tetraploids through a triploid bridge in some regions is also discussed.
- Klíčová slova
- Autopolyploidy, F-statistics, Vicia cracca, allozymes, artificial pollination, fixed heterozygosity, genetic differentiation, genetic diversity, heterozygosity, inbreeding depression, mating system, meiotic chromosomes,
- MeSH
- alely MeSH
- diploidie * MeSH
- genetická variace * MeSH
- heterozygot MeSH
- izoenzymy genetika MeSH
- opylení genetika MeSH
- populační genetika * MeSH
- samooplození genetika MeSH
- semena rostlinná genetika MeSH
- tetraploidie * MeSH
- vikev genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Evropa MeSH
- Slovenská republika MeSH
- Názvy látek
- izoenzymy MeSH
Many recent studies have explored the effects of present and past landscape structure on species distribution and diversity. However, we know little about the effects of past landscape structure on distribution of genetic diversity within and between populations of a single species. Here we describe the relationship between present and past landscape structure (landscape connectivity and habitat size estimated from historical maps) and current genetic structure in a perennial herb, Succisa pratensis. We used allozymes as co-dominant markers to estimate genetic diversity and deviation from Hardy-Weinberg equilibrium in 31 populations distributed within a 5 km(2) agricultural landscape. The results showed that current genetic diversity of populations was related to habitat suitability, habitat age, habitat size and habitat connectivity in the past. The effects of habitat age and past connectivity on genetic diversity were in most cases also significant after taking the current landscape structure into account. Moreover, current genetic similarity between populations was affected by past connectivity after accounting for current landscape structure. In both cases, the oldest time layer (1850) was the most informative. Most populations showed heterozygote excess, indicating disequilibrium due to recent gene flow or selection against homozygotes. These results suggest that habitat age and past connectivity are important determinants of distribution of genetic diversity between populations at a scale of a few kilometres. Landscape history may significantly contribute to our understanding of distribution of current genetic structure within species and the genetic structure may be used to better understand landscape history, even at a small scale.
- MeSH
- alely MeSH
- Dipsacaceae genetika MeSH
- ekosystém * MeSH
- genetická variace * MeSH
- genetické markery genetika MeSH
- genetické struktury * MeSH
- heterozygot MeSH
- inbreeding MeSH
- izoenzymy genetika MeSH
- populační genetika * MeSH
- regresní analýza MeSH
- rostlinné proteiny genetika MeSH
- selekce (genetika) MeSH
- tok genů MeSH
- životní prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- genetické markery MeSH
- izoenzymy MeSH
- rostlinné proteiny MeSH
Total amylase activity in serum and urine is formed by pancreatic (P) and salivary (S) isoenzymes. The evaluation of isoamylases provides better information on enzyme changes during the disease than total activities alone. The resolution of pancreatic from extrapancreatic origin of hyperamylasemia may be clinically important. The experience obtained from the analysis of isoamylases in more than 1500 patients with different clinical diagnoses we compare with a contemporary knowledge of disturbances in amylase activities. We developed a method separating quantitatively both isoamylases on the mini-columns of ion-exchanger which we used in routine clinical investigation. In the first section we selected the findings on physiology and biochemistry of isoamylases. We described for the first time a significant decrease of P-isoamylase activity in serum during the intravenous infusions of hypertonic glucose, amino acids and during acute hypercalcaemia. We suggested that hypertonic glucose, amino acids and calcium may regulate directly or indirectly the amylase flux from acinar cells in the pancreas across basolateral membrane into blood. This endocrine secretion of amylase may be important in different clinical conditions in which changes of neurohumoral and/or hormonal regulation are developed. The isoamylase activities in patients with different diagnosis are analyzed in the clinical section. The results may be correctly evaluated only in connection with the pathogenesis of isoamylase changes. Disorders of the organs producing amylase (i.e. pancreas or salivary glands) may induce changes of isoamylases depending on their functional status. A progressive loss of amylase producing cells may be accompanied by a decrease of enzyme activity in serum as was described in chronic pancreatitis with exocrine insufficiency. However, the amylase activity in serum is significantly influenced by clearance mechanisms, too. Disorders of the liver or kidneys are accompanied predominantly with hyperamylasemia caused by the disturbed clearance mechanisms. The amylase activity in serum is a consequence of the result between input and output of the enzyme within the blood stream. Some humoral and hormonal regulations are able to modulate both processes in vivo. We suppose that pathogenetic standpoint has the main role for correct interpretation of isoamylase activities. The pathogenesis of hyperamylasemia is therefore discussed in single chapters. In conclusion, the isoamylase activities in serum and urine are influenced beside genetic background by many factors in health and disease which may be respected during the evaluation of the results.
- MeSH
- amylasy metabolismus MeSH
- izoenzymy metabolismus MeSH
- lidé MeSH
- příušnice enzymologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
- Názvy látek
- amylasy MeSH
- izoenzymy MeSH
- MeSH
- izoenzymy MeSH
- kolorimetrie MeSH
- koncentrace vodíkových iontů MeSH
- L-laktátdehydrogenasa analýza MeSH
- tetrazoliové soli * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- izoenzymy MeSH
- L-laktátdehydrogenasa MeSH
- tetrazoliové soli * MeSH
Syntheses of conjugates of garden pea (Pisum sativum) and grass pea (Lathyrus sativus) amine oxidases (PSAO and GPAO respectively) with BCD (beta-cyclodextrin), performed to improve the thermostability of the enzymes, are described in the present study. Periodate-oxidized BCD reacted with the enzyme proteins via free primary amino groups in a buffered solution containing cyanoborohydride as a reductant. Although the specific activities of PSAO and GPAO partially decreased after modification, Km values determined for the best diamine substrates remained almost unchanged. Both the BCD conjugates could be incubated at 65 degrees C for 30 min without considerable inactivation, and the residual activity remained detectable even after incubation at 75 degrees C. The conjugates contained approx. 30% of neutral sugars. Molecular masses of BCD-PSAO and BCD-GPAO (180 kDa), as estimated by gel-permeation chromatography, were higher compared with the value of 145 kDa for the native enzymes. This was in good correlation with the number of modified lysine residues determined by a spectrophotometric method. Peptide mass fingerprints of tryptic digests of BCD-PSAO and BCD-GPAO were less specific than those of the native enzymes when compared with the database sequence of PSAO. As a consequence of the modification, many unidentified peaks were observed in the digests of the studied conjugates that were not seen in the digests of native PSAO and GPAO. Only some of these peaks overlapped between BCD-PSAO and BCD-GPAO. The BCD conjugates described in the present study represent suitable candidates for biotechnological applications, e.g. in analyses using biosensors, which might benefit from increased storage stability and amine oxidation at high temperatures.
- MeSH
- aktivace enzymů MeSH
- beta-cyklodextriny chemie MeSH
- hrách setý enzymologie MeSH
- izoenzymy chemie MeSH
- Lathyrus enzymologie MeSH
- stabilita enzymů MeSH
- substrátová specifita MeSH
- teplota MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- beta-cyklodextriny MeSH
- betadex MeSH Prohlížeč
- izoenzymy MeSH
- MeSH
- benzoáty chlorortuťnaté farmakologie MeSH
- chromatografie MeSH
- hořčík farmakologie MeSH
- izoenzymy analýza izolace a purifikace MeSH
- malátdehydrogenasa analýza izolace a purifikace MeSH
- oxalacetáty farmakologie MeSH
- spektrofotometrie MeSH
- Streptomyces účinky léků enzymologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- benzoáty chlorortuťnaté MeSH
- hořčík MeSH
- izoenzymy MeSH
- malátdehydrogenasa MeSH
- oxalacetáty MeSH
- MeSH
- akutní nemoc MeSH
- hepatitida diagnóza MeSH
- izoenzymy MeSH
- L-laktátdehydrogenasa * MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- izoenzymy MeSH
- L-laktátdehydrogenasa * MeSH
Isoenzymes of phosphoglucomutase and hexokinase were repeatedly evaluated using starch gel electrophoresis in polyxenic cultures of Entamoeba histolytica. In two out of 18 strains spontaneous changes of isoenzyme patterns were recorded. While originally they were categorized into virulent group of zymodemes, following isoenzyme analysis classified them as non-virulent. The relation between virulence and isoenzyme pattern is questionable.
- MeSH
- časové faktory MeSH
- ektroforéza na škrobovém gelu MeSH
- Entamoeba histolytica enzymologie patogenita MeSH
- izoenzymy * MeSH
- kultivační média MeSH
- kultivované buňky MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- izoenzymy * MeSH
- kultivační média MeSH
