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71.
Riitta Puupponen-Pimiä Markku Saloheimo Tuija Vasara Runar Ra Janka Gaugecz Ulrika Kurtén Jonathan K. C. Knowles Sirkka Keränen Veli Kauppinen 《Plant molecular biology》1993,23(2):423-428
We have isolated the birch homologue (BP8) for the carrot embryogenic gene DC8 by heterologous hybridization. The birch BP8 gene encodes a putative protein of 53 kDa, showing 52% sequence identity with the DC8 gene at the amino acid level. The putative BP8 protein contains 20 repeats of 11 amino acids and thus belongs to the group of LEA proteins isolated from such plants as carrot, cotton and wheat. Northern hybridization of mRNA isolated from birch cells representing different stages of somatic embryogenesis and non-embryogenetic material with a PB8 probe gave no signals, suggesting a low expression level of the BP8 gene. 相似文献
72.
Glycoprotein Ibalpha (GP Ibα; CD 42b; hereafter GPIBA) is a component of the cell surface receptor for the von Willebrand factor (vWf) on platelets.
Immunizations against various platelet surface antigens play a major role in neonatal alloimmune thrombocytopenia and in post-transfusion
purpura. Only one antigenic polymorphism in GPIBA has thus far been established: the HPA-2 (Ko) alloantigen system. To screen
other polymorphisms in GPIBA systematically, we analyzed the whole coding sequence of the GPIBA gene in 50 Finnish blood donors using the single-strand conformation polymorphism method. In addition to the known polymorphisms,
we detected three others. Sequencing of the gene segments carrying the new polymorphisms revealed that none of them changed
the predicted amino acid sequence. Polymorphism designated RS was located five base pairs upstream from the initiation codon at position 3064 and had the gene frequency of 16% for R and 84% for S, respectively, in the Finnish population, and it was detectable by the restriction enzyme Hae III. The EF polymorphism was at position 3842 (Asn242) and the gene frequencies were 97% for E and 3% for F. The KL polymorphism was at position 4142 (Arg342) and the gene frequencies were 98% for K and 2% for L. The five polymorphic positions in GPIBA formed altogether six different alleles of the gene. The data suggest that there
are only a few variable amino acids in GPIBA.
Received: 16 January 1996 / Revised: 21 March 1996 相似文献
73.
Although several climatic factors are expected to change simultaneously in the future, the effect of such combined changes on plants have seldom been tested under field conditions. We report on a field experiment with dark-leaved willow, Salix myrsinifolia, subjected to enhancements in ultraviolet-A (UVA), UVB radiation and temperature, setup in Joensuu, Eastern Finland. S. myrsinifolia is a dioecious species, known as an important food plant for many herbivores. Cuttings of eight clones, four of each sex, of dark-leaved willow were planted in the field in spring 2009. In both 2009 and 2010, the total biomass increased significantly with temperature, and in 2010 there was an additive effect of UVB radiation. Both height and diameter increased with temperature in 2009, while the effect on height growth ceased in 2010. Males had greater diameter growth than females in 2010. Most phenolic compounds in the leaves decreased under enhanced temperature in both growing seasons. In 2010, four of six salicylates increased in response to enhanced temperature. Some quercetin derivatives increased under enhanced UVB radiation. Females had higher concentrations of chlorogenic acids than males, and while enhanced temperature reduced chlorogenic acid in females only, luteolins were reduced only in males. In summary, the combined enhancements gave no effects in addition to those that appeared under the single-factor treatments, except for the additive effect of UVB on temperature-increased biomass. The few gender-related differences found in response to climate change do not allow any marked expectations of future climate-induced changes in sex ratios. 相似文献
74.
Riitta Tegelberg Satu Turtola Matti Rousi Beat Meier Riitta Julkunen-Tiitto 《Trees - Structure and Function》2006,20(3):299-303
Hybridisation between certain willow species is a common feature leading to novel genotypes varying in growth rate and stress tolerance. The objective of this 4-week study was to investigate the effects of decreased watering, enhanced ultraviolet-B irradiation (UV-BBE, 280–315 nm, 7.2 kJ m−2 day−1) and combined decreased watering and enhanced UV-B irradiation on di- and polyamines in the leaves of Salix myrsinifolia and its hybrid with S. myrsinites. Control plantlets were well-watered and exposed to ambient UV-B irradiation (UV-BBE, 3.6 kJ m−2 day−1). HPLC analyses showed that the constitutive concentrations of soluble di- and polyamines varied markedly between S. myrsinifolia and its hybrids. The degree of responses to treatments also varied: in S. myrsinifolia, concentrations of free putrescine were clearly increased by reduced watering, while in the hybrid willow, change in putrescine was less pronounced and not significant. Results also showed that the increase in putrescine in S. myrsinifolia by reduced watering was mitigated by concurrent enhancement of UV-B irradiation. There were no direct UV-B effects on the soluble polyamines. 相似文献
75.
Titta Kotilainen Jari Haimi Riitta Tegelberg Riitta Julkunen-Tiitto Elina Vapaavuori Pedro Jose Aphalo 《Oecologia》2009,161(4):719-728
Solar ultraviolet (UV)-A and UV-B radiation were excluded from branches of grey alder (Alnus incana) and white birch (Betula pubescens) trees in a field experiment. Leaf litter collected from these trees was used in microcosm experiments under laboratory conditions.
The aim was to evaluate the effects of the different UV treatments on litter chemical quality (phenolic compounds, C, N and
lignin) and the subsequent effects of these changes on soil fauna and decomposition processes. We measured the decomposition
rate of litter, growth of woodlice (Porcellio scaber), soil microbial respiration and abundance of nematodes and enchytraeid worms. In addition, the chemical quality of woodlice
feces was analyzed. The exclusion of both UV-A and UV-B had several effects on litter chemistry. Exclusion of UV-B radiation
decreased the C content in litter in both tree species. In alder litter, UV exclusion affected concentration of phenolic groups
variably, whereas in birch litter there were no significant differences in phenolic compounds. Moreover, further effects on
microbial respiration and chemical quality of woodlice feces were apparent. In both tree species, microbial CO2 evolution was lower in soil with litter produced under exclusion of both UV-A and UV-B radiation when compared to soil with
control litter. The N content was higher in the feces of woodlice eating alder litter produced under exclusion of both UV-A
and UV-B compared to the control. In addition, there were small changes in the concentration of individual phenolic compounds
analyzed from woodlice feces. Our results demonstrate that both UV-A and UV-B alter litter chemistry which in turn affects
decomposition processes. 相似文献
76.
Mervi T. Hyvönen Riitta Sinervirta Nikolay Grigorenko Alex R. Khomutov Jouko Vepsäläinen Tuomo A. Keinänen Leena Alhonen 《Amino acids》2010,38(2):575-581
The role of polyamines in carbon tetrachloride (CCl4)-induced organ injury was studied in syngenic rats and transgenic rats with activated polyamine catabolism. In syngenic rats,
administration of CCl4 resulted in the induction of hepatic spermidine/spermine N
1-acetyltransferase (SSAT), accumulation of putrescine, reduction in spermine level and appearance of moderate hepatic injury
within 24 h. Upon treatment with CCl4, transgenic rats overexpressing SSAT displayed induction of both hepatic and pancreatic SSAT, with subsequent accumulation
of putrescine and decrease of both spermidine and spermine pools. Administration of CCl4 in SSAT transgenic rats induced not only massive hepatic injury, but also severe acute necrotizing pancreatitis. Pretreatment
of the animals with catabolically stable functional polyamine mimetic, α-methylspermidine (MeSpd) prevented pancreatic and
hepatic injury in SSAT rats and markedly reduced liver damage in syngenic animals. As assessed by immunostaining of proliferating
cell nuclear antigen, MeSpd increased the amount of regenerating hepatocytes in both genotypes. These results show that CCl4 induces hepatic and pancreatic polyamine catabolism, and the extent of organ damage correlates with the degree of polyamine
depletion. Furthermore, MeSpd protects against CCl4-induced hepatic and pancreatic damage and promotes tissue regeneration. 相似文献
77.
Mari Pekkanen-Mattila Markku Pelto-Huikko Ville Kujala Riitta Suuronen Heli Skottman Katriina Aalto-Setälä Erja Kerkelä 《Histochemistry and cell biology》2010,133(5):595-606
Human embryonic stem cell (hESC) differentiation in embryoid bodies (EBs) provides a valuable tool to study the interplay
of different germ layers and their influence on cell differentiation. The gene expression of the developing EBs has been shown
in many studies, but the protein expression and the spatial composition of different germ layers in human EBs have not been
systematically studied. The aim of the present work was to study the temporal and spatial organisation of germ layers based
on the expression of mesoderm (Brachyury T), endoderm (AFP) and ectoderm (SOX1) markers during the early stages of differentiation
in eight hESC lines. Tissue multi-array technology was applied to study the protein expression of a large number of EBs. According
to our results, EB formation and the organisation of germ layers occurred in a similar manner in all the lines. During 12 days
of differentiation, all the germ layer markers were present, but no obvious distinct trajectories were formed. However, older
EBs were highly organised in structure. Pluripotency marker OCT3/4 expression persisted unexpectedly long in the differentiating
EBs. Cavity formation was observed in the immunocytological sections, and caspase-3 expression was high, suggesting a role
of apoptosis in hESC differentiation and/or EB formation. The expression of Brachyury T was notably low in all the lines,
also those with the best cardiac differentiation capacity, while the expression of SOX1 was higher in some lines, suggesting
that the neural differentiation propensity may be detectable already in the early stages of EB differentiation. 相似文献
78.
Jenni Leppänen Perttu Seppä Kari Vepsäläinen Riitta Savolainen 《Molecular ecology》2015,24(10):2463-2476
Pairs of obligate social parasites and their hosts, where some of the parasites have recently diverged from their host through intraspecific social parasitism, provide intriguing systems for studying the modes and processes of speciation. Such speciation, probably in sympatry, has also been propounded in the ant Myrmica rubra and its intraspecific social parasite. In this species, parasitism is associated with queen size dimorphism, and the small microgyne has become a social parasite of the large macrogyne. Here, we investigated the genetic divergence of the host and the parasite queen morphs in 11 localities in southern Finland, using nuclear and mitochondrial markers of queens and workers. We formulated and tested four speciation‐related hypotheses that differed in the degree of genetic divergence between the morphs. The queen morphs were genetically distinct from each other with little hybridization. In the nuclear data, when localities were nested within queen morphs in the hierarchical amova , 39% of the genetic variation was explained by the queen morph (standardized F'CT = 0.63, uncorrected FCT = 0.39), whereas 18% was explained by the locality (F'SC = 0.39, FSC = 0.29). This result corroborated the hypothesis of advanced sympatric speciation. In contrast, the mitochondrial DNA could not settle between the hierarchical levels of locality and queen morph, thus substantiating equally the hypotheses of incipient and advanced sympatric speciation. Together, our results support the view that the microgynous parasite has genetically diverged from its macrogynous host to the level of a nascent species. 相似文献
79.
Sandy Sampaio Videira Michele de Cássia Pereira e Silva Péricles de Souza Galisa Armando Cavalcante Franco Dias Riitta Nissinen Vera Lúcia Baldani Divan Jan Dirk van Elsas José Ivo Baldani Joana Falcão Salles 《Plant and Soil》2013,373(1-2):737-754
Aims
Previous studies have shown that elephant grass is colonized by nitrogen-fixing bacterial species; however, these results were based on culture-dependent methods, an approach that introduces bias due to an incomplete assessment of the microbial community. In this study, we used culture-independent methods to survey the diversity of endophytes and plant-associated bacterial communities in five elephant grass genotypes used in bioenergy production.Methods
The plants of five genotypes of elephant grass were harvested from the experimental area of Embrapa Agrobiologia and divided into stem and root tissues. Total DNA and RNA were extracted from plant tissues and the bacterial communities were analyzed by DGGE and clone library of the 16S rRNA and nifH genes at both the cDNA and DNA levels.Results
Overall, the patterns based on DNA- and RNA-derived DGGE-profiles differed, especially within tissue samples. DNA-based DGGE indicated that both total bacterial and diazotrophic communities associated with roots (rhizoplane?+?endophytes) differed clearly from those obtained from stems (endophytes). These results were confirmed by the phylogenetic analyses of RNA-derived sequences of 16S rRNA (total bacteria; 586 sequences), but not for nifH (186). In fact, rarefaction analyses showed a higher diversity of diazotrophic organisms associated with stems than roots. Based on 16S rRNA sequences, the clone libraries were dominated by sequences affiliated to members of Leptotrix (12.8 %) followed by Burkholderia (9 %) and Bradyrhizobium (6.5 %), while most of the nifH clones were closely related to the genus Bradyrhizobium (26 %).Conclusions
Our results revealed an unexpectedly large diversity of metabolically active bacteria, providing new insights into the bacterial species predominantly found in association with elephant grass. Furthermore, these results can be very useful for the development of new strategies for selection of potential bacteria that effectively contribute to biological nitrogen fixation and enhance the sustainable production of elephant grass as bioenergy crop. 相似文献80.
Jing Liu Dong Li Bin Cao Yu-xia Li Riitta Herva Yun-shang Piao Yan-Ling Wang 《The journal of histochemistry and cytochemistry》2007,55(7):701-708
SWAP-70 has been demonstrated as a multiple functional signaling protein involved in formation of membrane ruffling induced by signal cascade of tyrosine kinase growth factor receptors. In the present study, the spatial and temporal expression pattern of SWAP-70 on human fetomaternal interface was investigated using specimens collected from tubal and normal pregnancies by in situ hybridization, immunohistochemistry, and Western blotting. Data showed an intense expression of SWAP-70 in trophoblasts at weeks 3-6 of fallopian implantation and at weeks 6-7 of normal pregnancy. The most intense expression was exhibited by those highly motile and invasive extravillous trophoblasts. From gestational week 8 on, the level of SWAP-70 in trophoblasts decreased significantly, and the signal was restricted in villous cytotrophoblast cells. In the in vitro cultured human trophoblast cell line, B6Tert-1, colocalization of SWAP-70 with F-actin was verified. Data in human placenta were similar to what we recently reported on rhesus monkey fetomaternal interface. Our results suggest that SWAP-70 may be involved in regulating migration and invasion of trophoblast cells during the processes of embryonic implantation and placentation in primates. 相似文献