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1.
Summary The angular dependence of1JC,H in model compounds related to -linked oligosaccharides has been established by FPT INDO quantum chemical calculations. Values calculated for models of (1 1)-, (1 2)-, (1 3)- and (1 4)-linked disaccharides were compared, and the effect of the orientation of HO-2 elucidated. The angular dependence of1JC,H on the torsional angles H and H and the solvent dielectric constant (s) was characterized in the form:1JC,H = A cos2+B cos + C sin2 + D since + E + Fe. The1JC,H values, measured by DEPT methods for C-1-H-1 and C-X-H-X in cellobiose, cyclic trisaccharide and hexopyranoses were used to adjust the calculated angular dependences. Based on the occurrence of the conformers for agarobiose, neoagarobiose, mannobiose and methyl -xylobioside, the thermodynamically averaged <1JC,H > values were calculated. The results obtained (<1JC-1,H-1 > 162.4, <1JC-4, H-4 > 147.6 Hz for methyl -xylobioside; <1JC-1,H-1 > 162.4 and <1JC-4,H-4] > 147.6 Hz for mannobiose; <1JC-1,H-1 > 162.8 Hz for neo agarobiose and <1JC-1,H-1 > 163.2 Hz for agarobiose) agree well with the experimental values of 162.7, 147.5, 160.4, 147.2, 160.9 and 165.7 Hz, respectively.  相似文献   

2.
A combination of molecular and in silico approaches was employed to assemble a survey of Na, K-ATPase genes contained in the ancestrally tetraploid genome of the Atlantic salmon (Salmo salar). Molecular characterization of genomic clones coding for the subunit revealed two single genes (1a and 2) and two pairs of presumably homeologous genes (1b/i-ii and 1c/i-ii). Each of the six genes showed high sequence similarity to isoforms previously isolated from rainbow trout and extensive structural differences relative to putative orthologs in the human genome. In silico analysis of expressed sequence tag (EST) collections indicated that at least five (1a, 1b, 1c, 2, and 3) and four (1a, 1b, 2, and 3b) subunit isoforms are expressed in Atlantic salmon. Meiotic linkage analysis further showed that Na, K-ATPase genes are dispersed throughout the salmon genome, with the exception of two multigene clusters on linkage groups AS-22 and AS-28. Duplicate gene copies for the isoform 1b were assigned to linkage groups with multiple homeologous anchors (AS-22 and AS-23), while 2 duplicates suggested a new homeologous affinity between AS-05 and AS-28. In addition, the comparison of linkage arrangements with rainbow trout also showed that the genomic organization of Na, K-ATPase genes is consistent with the evolutionary conservation of syntenic chromosome regions between these species.Electronic Supplementary Material Supplementary material is available for this article at .  相似文献   

3.
Mesophyll protoplasts were isolated from leaves of three cultivars of Lycopersicon esculentum (L.) Mill., namely Hilda 72, Rutgers and Rentita, and from the wild tomato species Lycopersicon peruvianum (L.) Mill. Protoplasts from L. peruvianum divided and grew actively in a liquid medium according to Zapata et al. (1977), whereas protoplasts from the tomato cultivars Hilda 72 and Rutgers showed comparable rates for cell division only, when the content of major elements in this medium was reduced to one half of the original concentration and when mannitol as osmoticum was replaced by glucose. In Rentita protoplasts no cell division could be observed in about 15 different modifications of the five basic culture media tested. The morphogenetic potential of these tomato cells was assessed by comparing the root and shoot formation of protoplasts and of leaf explants. L. peruvianum exhibited the highest potential. Calli derived from protoplasts regenerated roots on Murastrige-Skoog agar containing 1 M benzylaminopurine (BAP) plus 10 M indole-3-acetic acid (IAA) and 0.1 M BAP plus 1 M IAA. Shoot formation occurred in the combinations of 10 M BAP with 0.1, 1.0, and 10 M IAA. Plantlets regenerated from the L. peruvianum calli could be grown in soil. No shoots or roots were regenerated from calli of Hilda 72 and Rutgers protoplasts in all combinations of BAP and IAA tested in the range from 0.1 M to 100 M, thus indicating the rather low morphogenetic potential of these protoplasts as compared to protoplasts from L. peruvianum leaves.Abbreviations BAP benzylaminopurine - IAA indole-acetic acid - TMV tobacco mosaic virus  相似文献   

4.
Summary Using the existing restriction map and probes from wheat and pea ct-DNA, seven protein genes have been localized in the chloroplast genome of N. tabacum. On the clock-like map, the location of each gene is indicated by its time zone: the 15.2 kD polypeptide of the cytochrome b/f complex at 315, cytochrome f at 430, LS of RuBPCase at 450, both and subunits of ATP synthase at or near 500, proton-translocating subunit of ATP synthase at 820, subunit of ATP synthase at 840 and the 32 kD protein at 930. The genome organization of Nicotiana chloroplast DNA is similar to spinach.  相似文献   

5.
On the basis of the filament rotation model that was elaborated for interpretations in cell motility, the lateral hydrodynamic effects of rotating filaments have been investigated by large-scale model experiments. Helices were rotated by small electric motors in a medium of high viscosity (honey or polyethyleneglycol). The observed effects, hitherto not investigated in detail by hydrodynamics, show some features that were attributed to the indefinable formative power or vital force of the past. The main effects generated by the rotating filaments are (1) flows and flow patterns with impact zones where flows collide, (2) regions of excessive pressure and negative pressure (corner effect) along a wall, (3) grooves and smoothly shaped ridges on a free fluid surface, and (4) rolling motions of freely hanging filaments. All effects and flow patterns depend on the appropriate distribution of rotating and counterrotating filaments. Each change of the rotational direction means a dramatic alteration. The application of the observed effects explains largely the function of the microtubule/microfilament hoops or helices during the cytokinesis of a plant cell. Interpretations or simulations are described for events as the formation of secondary wall thickenings, the orientation of their microfibrils, the motion of the preprophase band microtubules, the formation of the phragmosome, the migration, stationary position and shape of the preprophase nucleus, the girdle-, septum- and H-piece formation of cell walls in algae and some events of morphogenesis inMicrasterias. Further interpretations are related to the lateral flows and to invaginations of free cell membranes, to lateral filament motions, to the right-left problem, to the selfintertwining of filaments, to the rotation of a cell body by its flagellum, to the repulsion of chromatids during meiosis and to the tetragonal and hexagonal arrangement of filaments.Dedicated to Prof. DrLothar Geitler on the occasion of the 90th anniversary of his birthday.  相似文献   

6.
Zusammenfassung Der Schalenkalk der Schwanen-Eischale — der in den exosphäritischen Schichten von den bekannten Globular-Inklusionen durchsetzt ist — enthält im Bereich der inneren Säulen zahllose luftgefüllte Spalten. Diese werden von Kristallflächen (insbesondere Rhomboederflächen) begrenzt und sind innerhalb eines jeden Calcitindividuums (Säulenprismas) einheitlich orientiert. So entsteht ein Rhomben- oder Blockmuster. Der Schalenquerschliff zeigt das Muster am deutlichsten; beim Übergang der inneren in die äußeren Säulen aber tritt es auch am Flachschliff klar hervor. Der zackige Verlauf der Lateralgrenzen der inneren Säulen beruht auf dem Verfugen der benachbarten Prismen entsprechend den Musterelementen. Das Muster findet sich auch bei anderen Anatiden; sein weiteres Vorkommen bedarf noch der Überprüfung.
Summary The lime of the swan's egg shell — containing in the exospheritical layers the well known globular inclusions—shows in the reach of the inner columns numberless airfilled clefts. These are bordered by crystal faces (especially rhomb faces) and are orientated uniformly within every calcite individual (column prism). So a rhomb- or block-pattern arises. The transverse ground section of the egg shell shows the pattern most distinct; but in the transition region from the inner to the outer columns it also can be seen cleary on the tangential ground section. The pronged cours of the lateral boundaries of the inner columns is caused by the indentation between the pattern elements of neighboured prisms. Also other Anatidae possess this pattern; its farther occurence needs more examination.
  相似文献   

7.
Summary There is little information on the energy turnover of carnivorous water insects. This study concerns the energy flow through an imaginal population of the water scorpion, Nepra rubra, a water bug common in the lake Neusiedler See in eastern Austria.Population dynamics, production and respiration were determined from 1972 to 1975 under conditions as natural as possible. The cumulative sum of production energy is small, comprising 179.3 J for and 223.8 J for , with an additional 241.6 J for reproduction. Food reserves, particularly fat accumulated in the fat body during prediapause, are utilized in winter and extensively by females during breeding the next spring. The largest fat content indicated for was 4.64 mg and 9.64 mg for (crude lipoids).The respiration rate is high even in winter. It is assumed that at this time oxygen is utilized exclusively for the oxydation of fats. Cumulative respiration energy for the adult stage was 2000.2 J for males and 3221.4 J for females. Total annual energy flow through a population of adults was about 663 kJ/100 m2 of which 596 kJ (=89%) were applied to respiration and 67 kJ (=11%) to production.Supported by the Kommission zur Erforschung des Neusiedler Sees of the Austrian Academy of Sciences  相似文献   

8.
This paper describes a model of a neural visual system of a higher animal, in which the capability of pattern recognition develops adaptively. To produce the adaptability, we adopted self-organizing cells, and with them modeled feature-detecting cells which were discovered by Hubel and Wiesel and whose plasticity was found by Blakemore and Cooper. Combining the self-organizing cells and the learning principle of a Perceptron-type system, we constructed a model of the whole visual system. The model is also equipped with an eye movement control mechanism for gazing, which reduces the number of selforganizing cells required for pattern recognition, thus contributing to their quick self-organization. Computer simulation and an experiment using a hardware simulator showed that self-organizing cells quickly become sensitive to the features often seen and that the resulted system can classify patterns with a rather small number of feature-detecting cells.  相似文献   

9.
The antiinsectan properties of the Fusarium graminearum-derived novel sterol sulfate, 4,4,24-trimethylcholesta-8,14,24(28)-trien-2,3,11,12-tetrol 12 acetate, 3-sulfate were tested on the corn earworm (Heliothis zea (Boddie), the fall armyworm (Spodoptera frugiperda (J. E. Smith), and the driedfruit beetle (Carpophilus hemipterus L.). The sterol sulfate could not be used as a sterol source by any of the insects. The sterol sulfate inhibited growth of S. frugiperda and C. hemipterus larvae at 2500 and 4000 ppm, respectively. Defensive implications of this compound are discussed.  相似文献   

10.
Radiolabeled human 2-microglobulin (2m) can bind to mouse histocompatibility (H-2) antigens on the cell surface or to partially purified H-2 antigens in solution. The complexes containing human 2m and H-2 antigens from C3H (H-2k) mice could be immunoprecipitated specifically with alloantisera, rabbit anti-H-2 xenoantisera, and with monoclonal H-2-specific antibodies. Specific association with H-2 antigens was also observed with other haplotypes. The only exception was B10.D2 (H-2 d ) from which complexes containing human 2M could only be precipitated with anti-H-2 xenosera. Thus radiolabeled human 2M can be used as a specific label for mouse H-2 antigens in precipitation and radioimmunoassays. The application of this finding extends to major histocompatibility complex antigens of other species, and to differentiation antigens with primary association with 2m.Abbreviations used in this paper MHC major histocompatibility complex - 2m 2-microglobulin - LcH Lens culinaris hemagglutinin  相似文献   

11.
The polymorphic variation of liver GM1 (NeuGc) ganglioside was found in inbred strains of the mouse. The genetic analysis using C57BL/10 (GM1-negative) and SWR (GM1-positive) mice revealed that a single autosomal gene (Ggm-1) was involved in the expression of liver GM1(NeuGc) and that C57BL/10 mice lacking GM1(NeuGc) expression carried a defective gene on Ggm-1. Since our previous study on H-2 congenic mice indicated that Ggm-1 was linked to the H-2 complex, in this study we measured recombination frequencies among Ggm-1, Go-1 and H-2K in the backcross progeny between (C57BL/10 × SWR)F1 and C57BL/10. Ggm-1 was mapped 1 cM centromeric to H-2K on chromosome 17.Abbreviations used in this paper GM1(NeuGc) Gal1-3GalNAc1-4 (NeuGc2-3)Gal1-4Glc1-ceramide - GM2(NeuGc) Gal1-4(Neu Gc2-3)Gal1-4Glc1-ceramide - GM3(NeuGc) NeuGc2-3Gal1-4 Glc1-ceramide - GD1a(NeuGc) NeuGc2-3Gal1-3GalNAc1-4 (NeuGc2-3)Gal1-4Glc1-ceramide  相似文献   

12.
Summary A bacterium capable of utilizing -pinene as a sole carbon and energy source was isolated from soil. This strain, named strain S201-1, which was identified as Pseudomonas maltophilia on the basis of its taxonomical properties, accumulated limonene, borneol, camphor, perillic acid, and 2-(4-methyl-3-cyclohexenylidene) propionic acid from -pinene in the culture broth. It was demonstrated that -pinene, -pinene, borneol, camphor, and a number of p-menthane derivatives were oxidized by this strain. Relations between the protonation of -pinene and the formation of the products by the microbe are discussed.  相似文献   

13.
Sensitivities to recombinant human tumor necrosis factor- (TNF-) and chemotherapeutic agents (cisplatin, peplomycin, methotrexate) were evaluated in 20 tumor cells of head and neck squamous cell carcinomas, using a dye uptake method. Also, numbers of TNF receptors of these tumor cells were measured by Scatchard plot analysis. There was no relationship between the number of TNF- receptors and the sensitivity to TNF-. Furthermore, there was no correlation between the sensitivity to TNF- and that to chemotherapeutic drugs, nor between the sensitivity to TNF- and the clinical response to chemotherapy including of cisplatin and peplomycin. The sensitivity to TNF- was higher in poorly differentiated carcinomas than in well differentiated ones.Abbreviations BSA Bovine serum albumin - CDDP Cisplatin - 5-Fu 5-fluorouracil - IC50 Inhibition concentration 50 - MTX Methotrexate - PLM Peplomycin - TNF- Tumor necrosis factor-  相似文献   

14.
An isolated β 1 exon next to the DR α gene in the HLA-D region   总被引:3,自引:0,他引:3  
A cosmid clone containing the DR gene and a 1 exon of a DR -related gene was isolated from a human cosmid clone bank made from the consanguineous DR7 cell line MANN. No other DR-related exons were found on this clone. The 1 exon was located about 15 kb away from the DR gene in a tail-to-tail (3 to 3) orientation. The exon contained several deleterious mutations: a defective splice site at the 5 end, two translational frame shifts (a 1 by deletion and a 1 bp insertion), and three extra cysteine residues. Nucleotide and amino acid sequence comparisons of the 1 exon indicated that although it is substantially different from other class II -chain genes, it is slightly more related to DR than to any other class 11 gene. The DR-related sequence was on a DNA fragment which showed no polymorphism on a panel of cell lines with Eco RI or Pst 1. These Southern blots, however, revealed a related, polymorphic sequence in the human genome. Nucleotide sequences in the intron flanking the 1 exon shared greater sequence homology than the 1 exon itself when compared with the DR genomic sequence. The exon may play a role in the generation of variation in expressed class II -chain genes and it may be a relic of a different subset of class II products.  相似文献   

15.
The organization of the major histocompatibility complex (MHC) class II region in cattle was investigated by Southern blot analysis using human probes corresponding to DO, DP, DQ, and DR genes. Exon-specific probes were also employed to facilitate the assessment of the number of different bovine class II genes. The results indicated the presence of single DO and DR genes, at least three DR genes, while the number of DQ genes was found to vary between MHC haplotypes. Four DQ haplotypes, DQ 1 1 to DQ 2 4, possessed a single DQ and a single DQ gene whereas both these genes were duplicated in eight other haplotypes, DQ 3 5 to DQ 9 12. No firm evidence for the presence of bovine DP genes was obtained. The same human probes were also used to investigate the genetic polymorphism of bovine class II genes. DQ DQ , DR DR , and DO restriction fragment length polymorphisms (RFLPs) were resolved and in particular the DQ restriction fragment patterns were highly polymorphic. Comparison of the present result with the current knowledge of the class II region in other mammalian species suggested that the DO, DP, DQ, DR, and DZ subdivision of the class II region was established already in the ancestor of mammals. The DP genes appear to be the least conserved class II genes among mammalian species and may have been lost in cattle. The degree of polymorphism of different class II genes, as revealed by RFLP analyses, shows striking similarities between species.  相似文献   

16.
To study the class II genes of the major histocompatibility region of the sheep genome, human HLA class II genes corresponding to the known subregions in man (DR, DQ, DP, DO, and DZ) were used for Southern hybridization analysis of sheep DNA and to probe a sheep genomic library. Hybridizing bands were noted for all probes except DP. DQ and and DR appear to be present as multicopy genes, while DR-, DZ-, , and DO -like genes appear to be single copy. All bands detected with the DP probe were also detectable with other chain probes. From eight -bacteriophage clones of a sheep genomic library nine distinct class II genes were identified. These genes were characterized by differential hybridization analysis and restriction mapping. Two genes were DR -like, three DQ-like and four DQ -like. The extensive cross-hybridization observed with chain probes was not seen with chain probes. The results of this study suggest that the major histocompatibility complex class II region of the sheep has a similar genetic organization to that of man, with the provisional exception of the DP subregion.Abbreviation used in this paper OLA ovine major histocompatibility complex  相似文献   

17.
Our laboratory is involved in investigating the role of T-cell receptor (Tcr) in collagen-induced arthritis (CIA). During these studies we found AU/ssJ (H-2 q ) mice to be resistant to CIA like SWR (H-2 q ), as compared with other H-2 q strains with wild-type Tcr like DBA/1 and B 10. Q. Upon screening with monoclonal antibodies F23.1 and KJ23a, AU/ssJ was found to be F23.1 negative (V 8 Tcr negative) and KJ23a positive (V 17a Tcr positive). Southern blot analysis on liver DNA using specific Tcr-V probes confirmed the deletion of V 8 gene family and also showed that AU/ssJ mice have deletions of V 9, V 13, V 12, and V 11 genes of Tcr. Further, these mice show a restriction fragment length polymorphism pattern with V 10, V 6, and V 17 probes similar to SWR mice as compared with 1310 mice. Since SWR and AU/ssJ are from different backgrounds, these studies indicate that specific variable region chain genes of Tcr are crucial for susceptibility to CIA in mice. Furthermore, these studies identify an additional inbred strain which has also deleted 50% of its Tcr-V genes.  相似文献   

18.
Summary Dominant alleles of the Kr1 and Kr2 genes reduce the crossability of hexaploid wheat with many alien species, including rye and Hordeum bulbosum, with Kr1 having the greater effect. However, a cytological study of wheat ovaries fixed 48 h after pollination showed that the wheat genotypes Highbury (kr1, Kr2) and Chinese Spring (Hope 5B) (kr1, kr2) were crossable with Seneca 60 maize, fertilization occurring in 14.4 and 30.7% of embryo sacs respectively. The latter figure was similar to the 29.7% fertilization found in Chinese Spring (kr1, kr2). Most embryo sacs in which fertilization occurred contained an embryo but lacked an endosperm and where an endosperm was formed it was usually highly aberrant. All three wheat x maize combinations were karyotypically unstable and rapidly eliminated maize chromosomes to produce haploid wheat embryos.  相似文献   

19.
The partition of native Escherichia coli -galactosidase and of two different fusion proteins comprised mainly of -galactosidase from E. coli was studied in aqueous two-phase systems composed of polyethylene glycol (PEG) and dextran. These fusions contain an amino-terminal segment from the E. coli outer membrane protein F (OmpF) and a linker peptide. Differences in the partition pattern could be observed for the three enzymes despite their similarity. Decreased polymer concentrations in the phase system increased the partition coefficient for all three -galactosidases.  相似文献   

20.
The rat major histocompatibility complex (RT1) encodes twin sets of class II molecules, each consisting of two polypeptide chains referred to as A and A , and E and E . A gene encoding the RTLA chain was isolated from a rat genomic library using an HLA-DQ chain cDNA as a probe. The nucleotide sequence of the coding regions of this gene was determined. Comparison of this sequence with those of the corresponding genes of mouse (H-2A ) and human (HLA-DQ ) revealed that this gene has been highly conserved during evolution, and that some parts of the molecule are more conserved than others. Analysis of the nucleotide sequence encoding the two external domains suggests that the membrane proximal domain has been subject to conservative selection, whereas replacement substitutions have been selected positively at certain residues within the amino terminal domain. The overall organization of the RT1.A gene is similar to that of the H-2A gene.  相似文献   

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