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1.
A phylogenetic analysis of the early branching lineages of the monocotyledons is performed using data from two plastid genes (rbcL and matK), five mitochondrial genes (atp1, ccmB, cob, mttB and nad5) and morphology. The complete matrix includes 93 terminals representing Acorus, the 14 families currently recognized within Alismatales, and numerous lineages of monocotyledons and other angiosperms. Total evidence analysis results in an almost completely resolved strict consensus tree, but all data partitions, genomic as well as morphological, are incongruent. The effects of RNA editing and potentially processed paralogous sequences are explored and discussed. Despite a decrease in incongruence length differences after exclusion of edited sites, the major data partitions remain significantly incongruent. The 14 families of Alismatales are all found to be monophyletic, but Acorus is found to be included in Alismatales rather than being the sister group to all other monocotyledons. The placement is strongly supported by the mitochondrial data, atp1 in particular, but it cannot be explained as an artifact caused by patterns of editing or by sampling of processed paralogues.  相似文献   

2.
It has been shown in a previous paper (8) that the prime product of reassociation of related DNA sequences under open experimental conditions are mismatched duplexes which undergo maturation upon further incubation. Due to this feature, the Tm value of the duplexes of a large number of DNAs is strongly dependent on the Cot value. Here we present data showing that the Tm of the duplexes of such type of DNAs depends also on the concentration of DNA in the range of one and the same Cot value. The significance of this finding in studying the taxonomic relationship by DNA-DNA hybridisation is discussed.Abbreviations Co = initial concentration of single-stranded DNA in moles of nucleotides per liter - t = time of incubation in seconds - Cot = the product of Co and t (mol. sec. 11) - PB = an equimolar mixture of NaH2PO4 and Na2HPO4, pH 6.8 - HAP = hydroxyapatite - Ti = incubation temperature - Tm = melting temperature - Te = elution temperature, i.e. the temperature at which one half of the DNA is eluted as single strands by HAP-thermal chromatography  相似文献   

3.
《Gene》1998,211(1):159-167
Genomic sequences of the self-incompatibility genes, the S-RNase genes, from two rosaceous species, Japanese pear and apple, were characterized. Genomic Southern blot and sequencing of a 4.5-kb genomic clone showed that the S4-RNase gene of Japanese pear is surrounded by repetitive sequences as in the case of the S-RNase genes of solanaceous species. The flanking regions of the S2- and Sf-RNase genes of apple were also cloned and sequenced. The 5′ flanking regions of the three alleles bore no similarity with those of the solanaceous S-RNase genes, although the position and sequence of the putative TATA box were conserved. The putative promoter regions of the Japanese pear S4- and apple Sf-RNase genes shared a stretch of about 200 bp with 80% sequence identity. However, this sequence was not present in the S2-RNase gene of apple, and thus it may reflect a close relationship between the S4- and Sf-RNase genes rather than a cis-element important in regulating gene expression. Despite the uniform pattern of expression of the rosaceous S-RNase genes, sequence motifs conserved in the 5′ flanking regions of the three alleles were not found, implying that the cis-element controlling pistil specific gene expression also locates at the intragenic region or upstream of the analyzed promoter region.  相似文献   

4.
Metal ions like Cu(II) and Zn(II) are accumulated in Alzheimer's disease amyloid plaques. The amyloid-β (Aβ) peptide involved in the disease interacts with these metal ions at neutral pH via ligands provided by the N-terminal histidines and the N-terminus. The present study uses high-resolution NMR spectroscopy to monitor the residue-specific interactions of Cu(II) and Zn(II) with (15)N- and (13)C,(15)N-labeled Aβ(1-40) peptides at varying pH levels. At pH 7.4 both ions bind to the specific ligands, competing with one another. At pH 5.5 Cu(II) retains its specific histidine ligands, while Zn(II) seems to lack residue-specific interactions. The low pH mimics acidosis which is linked to inflammatory processes in vivo. The results suggest that the cell toxic effects of redox active Cu(II) binding to Aβ may be reversed by the protective activity of non-redox active Zn(II) binding to the same major binding site under non-acidic conditions. Under acidic conditions, the protective effect of Zn(II) may be decreased or changed, since Zn(II) is less able to compete with Cu(II) for the specific binding site on the Aβ peptide under these conditions.  相似文献   

5.
The nucleotide sequences of the maize plastid genes for the alpha subunit of CF1 (atpA) and the proteolipid subunit of CF0 (atpH) are presented. The evolution of these genes among higher plants is characterized by a transition mutation bias of about 2:1 and by rates of synonymous and nonsynonymous substitution which are much lower than similar rates for genes from other sources. This is consistent with the notion that the plastid genome is evolving conservatively in primary sequence. Yet, the mode and tempo of sequence evolution of these and other plastid-encoded coupling factor genes are not the same. In particular, higher rates of nonsynonymous substitution in atpE (the gene for the epsilon subunit of CF1) and higher rates of synonymous substitution in atpH in the dicot vs. monocot lineages of higher plants indicate that these sequences are likely subject to different evolutionary constraints in these two lineages. The 5'- and 3'-transcribed flanking regions of atpA and atpH from maize, wheat and tobacco are conserved in size, but contain few putative regulatory elements which are conserved either in their spatial arrangement or sequence complexity. However, these regions likely contain variable numbers of "species-specific" regulatory elements. The present studies thus suggest that the plastid genome is not a passive participant in an evolutionary process governed by a more rapidly changing, readily adaptive, nuclear compartment, but that novel strategies for the coordinate expression of genes in the plastid genome may arise through rapid evolution of the flanking sequences of these genes.  相似文献   

6.
Despite a long tradition of research in applied genetics, particularly in agricultural research, in Italy the transition to the new knowledges and techniques of molecular biology was long and difficult. Political and financial constraints made academic institutions very slow to grasp the importance of molecular approaches to biology and medicine. In fact, the main studies concerning problems of molecular biology took place inside non-academic institutions. We reconstruct the complex paths leading to the birth of the International Laboratory of Genetics and Biophysics (LIGB) in Naples, and describe its work and activities in the period in which it was directed by its creator, Adriano Buzzati-Traverso, between 1962 and 1969. The origins of the LIGB are inextricably bound to the growth of biophysical research at the University of Pavia and at the Higher Health Institute in Rome. For a short period, with the aid provided by Italian and European physicists to biological research on the effects of nuclear radiation, LIGB became a focal point in European molecular biology. In 1968 the scientific and educational activities of the LIGB dramatically fell victim to the contradictions of the Italian academic and scientific system, and to the political climate which emerged in Italy at the time.  相似文献   

7.
Tradescantia pallida cv. purpurea, a popular garden plant in Brazil, was used for the Tradescantia micronucleus (Trad-MCN) assay. In situ monitoring of the genotoxicity of air pollutants was carried out by sentinel approach, using the plant grown in the field or using the plants in pots which were carried to the monitoring sites. Two highly polluted sites, in S?o Paulo city (Cerqueira Cesar and Congonhas) and two rural sites (the cities of Pirassununga, 200 km and Caucaia do Alto, 50 km from S?o Paulo, respectively) were chosen for this study, in order to determine the gradient difference of the air pollution levels. Sentinel plants in Congonhas site presented the highest frequency of micronuclei (4.4%), in comparison with 2.2 and 2.3% found in plants from Pirassununga and Cerqueira Cesar sites, respectively (Kruskal-Wallis; P<0.020). Significant increases (F test; P<0.0001) in the frequency of micronuclei were observed in plants exposed in the polluted urban sites (Cerqueira Cesar: 5.7%; Congonhas: 7.1% and Caucaia do Alto: 2.3%). The increase in the frequency of micronuclei observed indicates the potential risk of mutagenicity in presence of high concentrations of pollutants.  相似文献   

8.
The anticonvulsant activity of bis(acetato)tetrakis(imidazole) copper(II), Cu(OAc)2(Im)4, was studied in normal mice using chemical convulsions induced by strychnine, thiosemicarbazide, picrotoxin, and pentelenetetrazol. Intraperitoneal administration of Cu(OAc) 2(Im)4, 50 mg/kg body mass, has delayed the onset of strychnine (3 mg/kg)-induced convulsion by 204% (p≤0.005) and thiosemicarbazide (20 mg/kg)-induced convulsant by 61% (p≤0.005). The changes in the onset of picrotoxin-(6 mg/kg) and pentelenetetrazol (50 mg/kg)-induced convulsions were not significant. The same dosage of the copper compound was effective in delaying the lethal time and reducing the mortality rate of treated animals. The anticonvulsant activity of Cu(OAc) 2(Im)4 complex against strychnine was not related to its constituents because the inorganic form of copper such as copper chloride, copper acetate, and the parent imidazole has no anticonvulsant activity. Other copper(II) complexes like copper(II)aspirinate and bis(acetato)bis(2-methyl imidazole) copper(II) were less effective.  相似文献   

9.
This study provides comprehensive documentation of silk production in the pest moth Helicoverpa armigera from gland secretion to extrusion of silk thread. The structure of the silk glands, accessory structures and extrusion apparatus are reported. The general schema of the paired silk glands follows that found for Lepidoptera. Morphology of the duct, silk press, muscle attachments and spigot are presented as a three-dimensional reconstruction and the cuticular crescent-shaped profile of the silk press is demonstrated in both open and closed forms with attendant muscle blocks, allowing advances in our knowledge of how the silk press functions to regulate the extrusion of silk. Growth of the spigot across instars is documented showing a distinctive developmental pattern for this extrusion device. Its shape and structure are related to use and load-bearing activity.  相似文献   

10.
James W. Moore 《Oecologia》1978,35(3):357-363
Summary The importance of algae in the diet of the oligochaetes Lumbriculus variegatus and Rhyacodrilus sodalis was determined from cellections made in a eutrophic bay from April 1977 to April 1978. During the summer, algae represented 70–85% of the gut contents of both species. The most frequently ingested algae were Cymatopleura elliptica, Cymbella spp., Epithemia turgida, Pinnularia spp., and Synedra ulna. Almost all species were consumed in proportion to their abundance in the environment. However, Nostoc pruniforme and Nostoc verrucosum were not eaten due to size selection. The high level of algal consumption exhibited by the oligochaetes was primarily related to the large standing crop of algae on the sediments. During the winter, when algal densities were low in the environment, detritus and associated bacteria were the major food source.  相似文献   

11.
Jere Kahanp?? 《ZooKeys》2014,(441):319-324
A Finnish checklist of the sphaeroceroid fly families Chyromyidae and Heleomyzidae is provided.  相似文献   

12.
A revised checklist of the flies of superfamilies Tephritoidea and Sciomyzoidea of Finland is provided. The following families are covered: Eurygnathomyiidae, Lonchaeidae, Neottiophilidae, Pallopteridae, Piophilidae, Platystomatidae, Tephritidae, Ulidiidae (Tephritoidea); Coelopidae, Dryomyzidae, Heterocheilidae, Phaeomyiidae, Sciomyzidae, Sepsidae (Sciomyzoidea).  相似文献   

13.
Parkinson’s disease (PD) is hallmarked by the abnormal intracellular inclusions (Lewy bodies or LBs) in dopaminergic cells. Amyloidogenic protein α-synuclein (α-syn) and iron (including both Fe(III) and Fe(II)) are both found to be present in LBs. The interaction between iron and α-syn might have important biological relevance to PD etiology. Previously, a moderate binding affinity between α-syn and Fe(II) (5.8 × 103 M−1) has been measured, but studies on the binding between α-syn and Fe(III) have not been reported. In this work, electrospray mass spectrometry (ES-MS), cyclic voltammetry (CV), and fluorescence spectroscopy were used to study the binding between α-syn and Fe(II) and the redox property of the resultant α-syn-Fe(II) complex. The complex is of a 1:1 stoichiometry and can be readily oxidized electrochemically and chemically (by O2) to the putative α-syn-Fe(III) complex, with H2O2 as a co-product. The reduction potential was estimated to be 0.025 V vs. Ag/AgCl, which represents a shift by −0.550 V vs. the standard reduction potential of the free Fe(III)/Fe(II) couple. Such a shift allows a binding constant between α-syn and Fe(III), 1.2 × 1013 M−1, to be deduced. Despite the relatively high binding affinity, α-syn-Fe(III) generated from the oxidation of α-syn-Fe(II) still dissociates due to the stronger tendency of Fe(III) to hydrolyze to Fe(OH)3 and/or ferrihydrite gel. The roles of α-syn and its interaction with Fe(III) and/or Fe(II) are discussed in the context of oxidative stress, metal-catalyzed α-syn aggregation, and iron transfer processes.  相似文献   

14.
Aspects of pantopod ontogeny have been known for a long time, but specific information is available for only a few species. Our account of the postembryonic development of Pycnogonum litorale is based on laboratory-reared individuals and SEM studies. We documented particularly all early developmental stages, with emphasis on morphogenetic changes of head structures and appendages. In P. litorale the protonymphal limbs, the chelicerae and two more uniramous legs, degenerate already during the larval phase; only the third one, the ovigers, reappears in male juveniles. Other Pantopoda vary in this aspect from retention of all three protonymphal appendages to their complete reduction, as in P. litorale. Accordingly, the two post-cheliceral larval appendages are separate legs in front of the walking legs in the adults, the ‘parapalps’ and the ‘ovigers’, but they do not occur in all pantopods. The scarcity of studies of the ontogeny of Pantopoda prevents us from a more conclusive picture, but our data are promising to state that additional such studies will increase the usability of ontogenetic data for a phylogenetic analysis of Pantopoda, the crown group of the Pycnogonida. We also discuss the phylogenetic implications of our data in the light of new information from Hox genes and developmental-biological data on body segmentation and tagmosis of the Chelicerata. These suggest the homology of chelicerae and antenn(ul)ae of other euarthropods. Accepting this, we conclude that the adult pycnogonid/pantopod head, the cephalosoma, corresponds to the euarthropod head and that the protonymph with three appendage-bearing segments may represent an even shorter, possibly phylogenetically older larval type than the euarthropod ‘head larva’ bearing four pairs of appendages. In further consequence, the fourth walking legs of Pycnogonida/Pantopoda should correspond to the first opisthosomal appendages, the chilaria, of euchelicerates. This implies that within Pycnogonida the post-prosomal region became compacted during evolution to a single leg-bearing segment plus a tubular end piece. Accordingly, neither the anterior nor the posterior functional boundaries of the walking-leg region correspond to the original tagma borders.  相似文献   

15.
Wielkopolska (western Poland) is a region, with good reason, called the main food base of Poland. All indices of agricultural production have always been there (since 19th century) much higher than elsewhere in the country (Ratajczak 1977/1978, Buszko 1984, Gorzelak 1989, Czyzewski et al. 1992; table 1). Such a situation had a beneficial effect on the amount of the income generated by a family of Wielkopolska and, thus, decided on its better financial status. Additionally, rural inhabitants of this region have always been characterised by a more advantageous educational structure in comparison with people of other Polish villages. Generally, it is easy to detect the relationship between the life standard, the level of education and family planning. The aim of this paper is to assess fertility of women from villages of Wielkopolska in the period of transformation of the political and economic system in Poland.  相似文献   

16.
The abundance and aggregation of eggs of Aedes aegypti L. and Aedes albopictus Skuse was evaluated in the municipalities of Cambé, Ibipor?, Jacarezinho, Maringá and Paranavaí, in the State of Paraná, Brazil by means of oviposition traps. Of the 225 installed traps, 100 were registered as positive for eggs; 4140 eggs were collected, thus demonstrating an highly aggregate distribution. Both species were registered in Cambé, Jacarezinho, Maringá and Paranavaí. Ae. albopictus was generally less abundant and was not present in Ibipor? nor in the oviposition traps of a second collection of Maringá. The relation between sexes for Ae. aegypti was approximately 1:1. In the comparison of the number of adults collected between the two species, a negative correlation was obtained in the samples of Maringá and Cambé, what was attributed the seasonality of these populations. The coexistence of these species indicates that both are under pressure by the control programs, therefore specific evaluations are necessary.  相似文献   

17.
Results of studies of the species composition of micronektonic fish and ichthyoplankton in the frontal zone of the Gulf Stream and subpolar waters at the stationary polygone “Titanic” performed in years with different hydrological situations (2000 and 2003) are provided. In July through August of 2000 during the penetration in the polygone of warm waters of the Gulf Stream, a considerable (almost by an order of magnitude) increase in the species composition of fish due to numerous tropical and subtropical species was recorded in comparison with the period of studies in 2003, close by dates, when the region was occupied by the cold waters of the Labrador Current. In the summer of 2000, of the 80 taxonomic forms found on the polygone, 48 were represented only by larval stages of development; 27, only by juvenile and adult specimens; and 5, by both larvae and juvenile and adult specimens. The last five species include Ceratoscopelus maderensis and Lampanyctus pusillus (Myctophidae), Arctozenus risso (Paralepididae), Stomias boa (Stomiidae), and Gonostoma elongatum (Gonostomatidae). In the summer of 2003, larval fish were absent in collections, and only juvenile and adult specimens of eight species from ten families were found. The bulk of the population of micronektonic fish in this period, as in the summer of 2000, was formed by the same arcto-boreal species of myctophids Benthosema glaciale.  相似文献   

18.
In 1865, the German botanist Julius Sachs published a seminal monograph entitled Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants) and hence became the founder of a new scientific discipline that originated 150 y ago. Here, we outline the significance of the achievements of Sachs. In addition, we document, with reference to his Vorlesungen über Pflanzen-Physiologie (Lectures on the Physiology of Plants, 1882), that Sachs was one of the first experimentalists who proposed the functional unity of all organisms alive today (humans, animals, plants and other “vegetable” organisms, such as algae, cyanophyceae, fungi, myxomycetes, and bacteria).  相似文献   

19.
This work revises the rhinoceros remains from the well-known early Villafranchian locality of Étouaires (Auvergne, France), which have been collected on multiple occasions since the late 18th century. The species Stephanorhinus elatus and S. etruscus are present, both represented mainly by postcranial elements. To identify them, a detailed preliminary analysis of the morphological differences between the postcranial skeletons of the two species has been undertaken, using the material from Vialette (Haute-Loire, early Villafranchian) and Senèze (Haute-Loire, early late Villafranchian) as comparison for S. elatus and S. etruscus respectively, plus some specimens of S. etruscus from Upper Valdarno (Tuscany, middle Villafranchian). These localities have been chosen because they all yielded only one of the two species. The morphological distinction between the two species is not easy, since the interspecific variability often overlaps and includes polymorphic characters. However, a few diagnostic characters are described, and intra-specific variability has been investigated as much as possible with the fossil material under investigation.  相似文献   

20.

Background  

The PDZ-LIM proteins are a family of signalling adaptors that interact with the actin cross-linking protein, α-actinin, via their PDZ domains or via internal regions between the PDZ and LIM domains. Three of the PDZ-LIM proteins have a conserved 26-residue ZM motif in the internal region, but the structure of the internal region is unknown.  相似文献   

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