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1.
This paper aims to achieve insight into various ecological theories in the Netherlands which have different, and sometimes opposing, views on the conservation of nature. Interviews, publications and archival research brought to light four separate theories: vitalistic/holistic, dynamic, cybernetic and chaos. Diversity is reached through stability according to vitalistic/holistic and cybernetic theories, but through change and instablility according to the dynamic and chaos theories. These two groups are working apart, and continue to have their own ideas. Prediction of the future is only possible with the vitalistic/holistic and cybernetic theories. Ecologists who adhere to these theories feel responsible and able in different ways to change ecological nature towards desirable end goals. The other two theories, dynamic and chaos, appear to be less activist. 相似文献
2.
Brian P. Lockhart Thomas P. Smith Christopher J. Bailey 《The Histochemical journal》1991,23(9):385-391
Summary An epidermolytic toxin target was observed in keratohyalin granules of sectioned epidermis by a direct fluorescence procedure using FTC-toxin, but not by an indirect procedure using sequential reaction with toxin, anti-toxin and FTC-secondary antibody. The investigation of the two procedures was extended to keratinocytes. A dispase digestion procedure yielded three fractions which corresponded to basal, spinous and granular cells according to biochemical and morphological criteria. It was shown that the direct and indirect procedures both detected the toxin target in the keratohyalin granules of granular cells, but that the indirect procedure was very insensitive. In control experiments, the profilaggrin of keratohyalin granules was detected readily in cells by a direct procedure using FTC-antiprofilaggrin but only weakly by an indirect double antibody procedure. Insensitivity to indirect procedures thus appears to be a particular property of the keratohyalin granule site. It was shown that the toxin target was readily accessible in permeable (trypsin-isolated) granular cells but inaccessible in impermeable (dispase-isolated) cells. 相似文献
3.
The conformational properties of the oligosaccharide chain of GM1 ganglioside containingN-glycolyl-neuraminic acid, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer, were studied through NMR nuclear Overhauser effect investigations on the monomeric ganglioside in dimethylsulfoxide, and on mixed micelles of ganglioside and dodecylphosphocholine in water. Several interresidual contacts for the trisaccharide core--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-were found to fix the relative orientitation of the three saccharides, while the glycosidic linkage of the terminal -Gal-was found to be quite mobile as the -Gal-(1-3)--GalNAc-disaccharide exists in different conformations. These results are similar to those found for two GM1 gangliosides containingN-acetyl-neuraminic acid and neuraminic acid [1].Abbreviations Ganglioside nomenclature is in accordance with Svennerholm [23] and the IUPAC-IUB Recommendations [24] GM3(Neu5Ac)
II3Neu5AcLacCer, -Neu5Ac-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer
- GM3(Neu5Gc)
II3Neu5GcLacCer, -Neu5Gc-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer
- GM1(Neu5Ac)
II3Neu5AcGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- GM1(Neu5Gc)
II3Neu5GcGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- GM1(Neu)
II3NeuGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu-(2-3)]--Glc-(1-1)-Cer
- GD1a
IV3Neu5AcII3Neu5AcGgOse4Cer, -Neu5Ac-(2-3)--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- GalNAc-GD1a
IV4GalNAcIV3Neu5AcII3Neu5AcGgOse4Cer, -GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- Neu
neuraminic acid
- Neu5Ac
N-acetyl-neuraminic acid
- Neu5Gc
N-glycolyl-neuraminic acid
- Cer
ceramide 相似文献
4.
Eugene K. Balon 《Environmental Biology of Fishes》2002,65(1):1-35
When I started the journal Environmental Biology of Fishes more than 25 years ago, it was designed to avoid any prejudices and scientific dogmas, to keep an open mind, and to allow publication of ideas that are irritating to followers of the so-called mainstream, ideas that few other journals dared to touch (Balon 1976, 1989d). While such articles in the journal were often ignored by the mainstream practitioners and the political establishment, none was ever opposed or proven wrong. As in many similar cases before, only time will show if these contributions were valid and of value to the advancement of knowledge.I have often wondered why it takes so long for some of the universal facts and ideas to be accepted or even to be known. I have come to believe that like with many textbooks some facts and conclusions are copied from one book to the next (as in the case of the origin of the common carp – Balon 1974, 1995a,b) without knowing or admitting that in the meantime new facts require new syntheses and conclusions. Even good scholars resist unknown facts or ideas. It is irritating that one's knowledge is inadequate or that others beat us to be first. I have wondered why wrong ideas persist for so long; but Bateson (1979, p. 206) already explained it to his daughter ... yes, your image of evolution is exact. And what Darwin called natural selection is the surfacing of the tautology or presupposition that what stays true longer does indeed stay true longer than what stays true not so long.After all it was Jean Baptiste Lamarckgrave, the founder of evolutionary theory, miserable, old, and blind, ... (Bateson 1972, p. xii) and/or Gottfried Treviranus who presented the truth long before the privileged Charles Darwin, alas in wrong languages. Over time, ignoring the truth became fashionable and the question which of the four theories of evolution (Løvtrup 1982) can be attributed to Darwin, if any, irrelevant. It is [exclaims Croizat 1977, transl. 1987, p. 137] a gross, very grave mistake to confuse Darwin as a historical figure with Darwin as an exalted figure of the thinking of biology (Croizat's italics).Nearly 30 years ago a BBC TV series and book on evolution glorified Darwin and molecular biology. Calder (1973, p. 9), the author of this book entitled The life game: evolution and the new biology felt that Darwin would [merely] need to know about the survival of the quickest, when it came to crossing the street. But the street was never crossed! Many TV viewers of the recent PBS series Evolution were again misled into believing that evolution was discovered by Darwin. Even Gould (2001) in the Introduction and the producer Hutton (2001) in the Foreword to the companion book of this series (Zimmer 2001) give the Darwinian evolution [sic] an exposé it hardly deserves. While such views have been repeatedly proven wrong, most scholars, with the exception of a few scientists, philosophers, and journalists, comfortably assume Darwin's priority in spite of numerous published evidences to the contrary. This myth is then fed to the general public. The following retrospective essay attempts to compile proofs in support of the evolutionary processes other than Darwin's natural selection and the gene-centric new synthesis, old by now as it is. 相似文献
5.
Summary Homology maps between bacteriophages 81, 80 and were constructed on the basis of electron microscope observation of DNA heteroduplexes. In 81/80 heteroduplex, the left half and the right terminal region of 13% the total molecular length were highly homologous, while the remaining region covering the early gene cluster was entirely nonhomologous. In 81/ heteroduplex, high-degree homologies were detected at the left 14% terminal region covering the head gene cluster, the central 3.8% region covering the att-int-xis region and the 1.3% Q homology region. Low-degree homologies of shorter length were scattered at the tail gene cluster, b2 region, cIII region, PQ region and SR region. Comparing our results with the homology maps of other lambdoid phages reported by Simon et al. (1971) and Fiandt et al. (1971), a phylogenic relation of 81 to other lambdoid phages and the role of recombination in the course of divergence of lambdoid phages are discussed. 相似文献
6.
Burtseva Yu. V. Verigina N. S. Sova V. V. Pivkin M. V. Zvyagintseva T. N. 《Applied Biochemistry and Microbiology》2003,39(5):475-481
The ability to produce extracellular O-glycosylhydrolases was studied in 14 strains of marine filamentous fungi sampled from the bottom sediments of the South China Sea. The following activities were detected in the culture liquids of the fungi: N-acetyl--D-glucosaminidase, -D-glucosidase, -D-galactosidase, -1,3-glucanase, amylase, and pustulanase. -1,3-Glucanases were isolated by ultrafiltration, hydrophobic interaction chromatography, and ion exchange chromatography, and their properties were studied. Data on products of enzymatic digestion of laminaran, absence of transglycosylation activity, and the pattern of action of natural inhibitors confirmed that -1,3-glucanase belonged to the exo type. Inhibitor analysis demonstrated the role of a thiol group and tryptophan and tyrosine residues in the catalytic activity. 相似文献
7.
Summary A mentally retarded boy with trisomy 9p is described. This trisomy arose through aberrant segregation of translocation chromosome during meiosis in his mother, who has a complex translocation involving chromosomes 9, 13, and 14. Based on both G-, Q-banding, and DNA replication patterns, the patient's karyotype was identified as 47,XY,-13, +(9;13) (9pter9q12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter). We suppose his mother's karyotype to be 46,XX,-9,-13,-14,+t(9;13) (9pterq12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter), +t(9;14) (9qter9q12::14pl?14qter). His phenotypically normal brother and sister are also carriers, having the same translocation chromosome as their mother. Clinical findings of the patient included peculiar face with hypertelorism, prominent nasal bridge and deformed helix, marked delay of osseous development, hypoplastic phalangia in fingers and toes, dysplastic nails and absence of digital triradii. 相似文献
8.
Masanori Sakurai Masaaki Iigo Tomohide Tamura Atsushi Otsu Yasutsuna Sasaki Hidehiko Nakano Kazuhiko Nakagawa Koichi Minato Yuichiro Ohe Nagahiro Saijo 《Cancer immunology, immunotherapy : CII》1988,26(2):109-113
Summary A comparative study of the antitumor effect of murine recombinant interferon() Mu-rIFN() and murine recombinant interferon() Mu-rIFN() on B16-F10 melanoma was conducted. Administration of Mu-rIFN() i.p. into C57BL/6 mice on days 1 to 7 produced a higher suppressive effect than Mu-rIFN() both on the growth of s.c. implanted tumor and on the formation of artificial pulmonary metastasis. Pharmacokinetic study of Mu-rIFN() demonstrated that high plasma levels were retained for a long time. In clonogenic assay, Mu-rIFN() at 1000 units/ml showed about 80% inhibition of colonies of B16-F10 melanoma. However, Mu-rIFN() hardly inhibited the colonies, even at 1000 units/ml. Augmentation of natural killer (NK) cytotoxicity was much greater with Mu-rIFN() than Mu-rIFN(), whereas Mu-rIFN() enhanced the cytotoxicity of peritoneal macrophages more strongly than Mu-rIFN(). Injection of Mu-rIFN() i.p. 1 day before tumor challenge also inhibited the formation of pulmonary metastasis of B16-F10 melanoma. However, pretreatment of mice with carrageenan significantly suppressed the inhibitory effect of Mu-rIFN(). From these results, it is suggested that the inhibitory effect of Mu-rIFN() on the tumor growth and metastases of B16-F10 melanoma is mediated partly by direct antitumor effect and partly by the activation of macrophages, and that the augmentation of NK activity contributes mainly to the antitumor effect of Mu-rIFN(). 相似文献
9.
M. García A. Gradillas C. del Campo E.F. Llama J.M. Sanchez-Montero J.V. Sinisterra 《Biotechnology letters》1997,19(10):999-1004
sThe hydrolysis of several esters catalyzed by lipase of Candida rugosa was used to analyse the interaction between the ester substrate and the active site and the geometry and steric restrictions of alk, ar and h subsites. Using 4-R-C H -CH(R)-COOEt and ethyl trans-cinnamate, the presence of a low electronic density zone in the ar pocket is described, the dimensions of the pocket produced by Phe-296 and Leu-297 in the alk subsite and the size of the h subsite are described. 相似文献
10.
The features of random chemical modification are defined with reference to acetylation of bovine hemoglobin, which has been performed in a random manner so that all of the amino groups that participate in functional chloride binding (i.e., those that are oxygen-linked) could be identified. Random chemical modification, which has objectives different from those of both specific (selective) and extensive chemical modification, has been achieved for bovine hemoglobin with the mild reagent,14C-methyl acetate phosphate; retention of function was demonstrated by a Hill coefficient ofn=2.2 for the modified hemoglobin. After removal of unmodified Hb chains, the mixture of randomly modified acetylated or chains was subjected to tandem treatment with trypsin and chymotrypsin. Peptides were purified by HPLC and identified by amino acid analysis. The amount of radioactivity in the acetylated amino group of a purified peptide was taken as an estimate of the degree of chloride binding. For bovine Hb, two amino groups of the -chain (Val-1 and Lys-99) and three amino groups of the -chain (Met-1, Lys-81, and Lys-103) were shown to be oxygen-linked (i.e., to have incorporated significantly more radioactivity in the deoxy conformation compared to the same site in the oxy conformation). Three of these sites were already known chloride-binding sites [i.e., Val-1(), the N-terminus of the -chain, and two sites between the 2 -chains of bovine hemoglobin, Met-1() and Lys-81(); these findings support the conclusions of the random modification approach. Two other chloride-binding sites, Lys-99() and Lys-103(), align the sides of the central dyad axis connecting the two well-known major chloride-binding sites of bovine Hb. The interrelationship of these five chloride-binding sites was assessed by improved molecular graphics. When viewed through the central dyad axis, the functional chloride-binding sites in the central cavity appear to be symmetrically related and to connect the two major chloride-binding sites. Modifiers or mutants that are directed at these regions in the central dyad axis may favor the deoxy conformation to provide a lower oxygen affinity by preventing the constriction of the central cavity that normally occurs upon oxygenation. 相似文献
11.
Neuronic or decision equations, first proposed as a mathematical model of neural activity, have shown, after their exact, compact solution was found, typical behaviours that make them natural tools for General Systems studies. It is shown here that their mathematical investigation is remarkably furthered by generalizing the triangular inequality to polygonal ones. These permit the immediate computation of the tensorial expansion of linearly separable boolean functions, and exhibit clearly the connection between their continuous and discontinuous aspects. 相似文献
12.
EF-1a binds aminoacyl-tRNA to the ribosome with the hydrolysis of GTP; the complex facilitates the exchange of GDP for GTP to initiate another round of elongation. To examine the subunit structure of EF-1 and phosphorylation by protein kinase CKII, recombinant , , and subunits from rabbit were expressed in E. coli and the subunits were reconstituted into partial and complete complexes and analyzed by gel filtration. To determine the availability of the and subunits for phosphorylation by CKII, the subunits and the reconstituted complexes were examined as substrates for CKII. Formation of the nucleotide exchange complex increased the rate of phosphorylation of the subunit and reduced the Km, while addition of to or the complex inhibited phosphorylation by CKII. However, a had little effect on phosphorylation of . Thus, the and subunits in EF-1 were differentially phosphorylated by CKII, in that phosphorylation of was altered by association with other subunits, while the site on was always available for phosphorylation by CKII. From the availability of the subunits for phosphorylation by CKII and the composition of the reconstituted partial and complete complexes, a model for the subunit structure of EF-1 consisting of (22)2 is proposed and discussed. 相似文献
13.
Dr. V. R. Southgate 《Cell and tissue research》1971,120(3):420-449
Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells. 相似文献
14.
InEchinops the flowers are surrounded by several scales and initiated in an acropetal and spiral succession on a cone-like inflorescence axis (Figs. 1–6). The floral organs originate in the following sequence: petals—stamens—carpels—pappus. The petals arise from a meristematic rim and therefore are already interconnected when they arise as primordia. This sympetalous zone remains rather inconspicuous for a long period, but eventually, the elongated corolla tube is formed through intercalary growth in a ring zone. Thereby, the stamens are moved upwards and form ledges on the corolla tube (Fig. 34). In the inferior ovary the usual zones of the typical angiospermous gynoecium can be distinguished, namely a synascidiate, symplicate and hemisymplicate zone. The ovule is borne on carpellary tissue. 相似文献
15.
The effect of an induced salmonid parr-to-smolt metamorphosis (smoltification) on the optical quality of the ocular lens was studied. In two separate experiments, rainbow trout (Oncorhynchus mykiss) parr were fed thyroxine in their diet to induce the metamorphosis. Lenses were excised at regular samplings during the treatment period and optically scanned using a custom scanning laser monitor. Radioimmunoassay was used to measure serum titers of thyroxine and 3,5,3-triiodo-L-thyronine. It was found that lens optical quality was consistently negatively correlated with 3,5,3-triiodo-L-thyronine levels, but not with thyroxine levels. To test if thyroid hormones are directly responsible for the change in optical quality, rainbow trout lenses were cultured for 72 h in a medium containing 3,5,3-triiodo-L-thyronine, but no effect was observed. The significance of these findings in the contexts of the fishes visual capabilities and smolting physiology is discussed. 相似文献
16.
Dennis J. Paulson Mahesh Gupta Radovan Zak Jiansheng Zhao 《Molecular and cellular biochemistry》1992,117(2):175-179
This study determined whether the beneficial effects of exercise training on the diabetic heart previously observed are associated with alterations in ventricular myosin heavy chain (MHC) isoform composition. Diabetes was induced in rats by i.v. streptozotocin. Trained rats were run on a treadmill for 60 min/day, 27 m/min, 10% grade. After 10 wks, ventricular MHC isoenzyme protein composition was analyzed for MHC composition using gel electrophoresis. -MHC and -MHC mRNA were determined by Northern and slot blot hybridization techniques. Both protein and mRNA analyses indicated that sedentary control rats exhibited a predominance of -MHC. Sedentary diabetics exhibited a shift to -MHC. Exercise trained diabetic rats showed a predominance of -MHC. The results indicate that treadmill exercise training of diabetic rat does not prevent the diabetes-induced shift in MHC composition towards the -MHC isoform, thus it is unlikely that the beneficial effects of exercise training on the diabetic heart, previously shown, are due to a normalization of the myosin isoform composition. 相似文献
17.
The purified isopropylmalate synthase of Alcaligenes eutrophus H 16 reacted with the following -keto acids and acyl-coenzyme A derivatives (in the sequence of decreasing affinities): -ketoisovalerate, -keto-n-valerate, -ketobutyrate and pyruvate; acetyl-CoA, propionyl-CoA, butyryl-CoA. malonyl-CoA, valeryl-CoA, and crotonyl-CoA. -Ketoisocaproate, however, is a strong inhibitor of the enzyme. All reactions catalyzed by isopropylmalate synthase were inhibited to the same extent by the endproduct l-leucine. the substrate saturation curves of -ketoisovalerate or other -keto acids and of acetyl-coenzyme A or other acyl-CoA derivatives had intermediary plateau regions; the Hill coefficient alternated between n
H
-values higher and lower than 1.0, indicating changes from positive to negative and from negative to positive cooperativity for the substrates. The products, isopropylmalate and free coenzyme A, showed competitive inhibition patterns against both substrates (-ketoisovalerate and acetyl-CoA). Free coenzyme A (1 M) inactivated the enzyme irreversibly. The 3-phosphate of coenzyme A and the free carboxyl group of -ketoisovalerate were involved in optimal binding of these substrates, but 3-dephospho-acetyl-coenzyme A and the methylester of -ketoisovalerate were also converted by this enzyme. A CH3–CH2-grouping of the -keto acids seemed to be necessary for binding this substrate.Abbreviations Used CoA
Coenzyme A
- Tris
Tris(hydroxymethyl)aminomethane hydrochloride
- DTNB
5,5-dithiobis-(2-nitrobenzoic acid)
- IPM
-Isopropylmalate
- KIV
-Ketoisovalerate
Prepared from doctoral thesis of the University of Göttingen 1973 相似文献
18.
R. Gondko W. Michalak A. Rogala Dr. B. Rózga M. Adamska 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1977,51(2):87-93
Summary Leghorn, Cornish and White Rock hens were subjected to starvation. Free amino acids were determined in blood samples taken after 48, 72 and 96 h of starvation. A progressive decrease in concentration of the majority of amino acids was found. Changes in amino acid concentrations during starvation were dependent on the breed of hen. 相似文献
19.
Patil Vishwanath Bjørnstad Åsmund Mackey James 《Molecular breeding : new strategies in plant improvement》2003,12(2):169-183
Doubled haploid (DH) progeny from a cross between the scald susceptible barley (Hordeum vulgare L.) cultivar Ingrid and the resistant accession CI 11549 (Nigrinudum) was evaluated for resistance in the pathogen Rhynchosporium secalis (Oudem) J.J. Davis. Two linked and incompletely dominant loci confer resistance CI 11549 against isolate 4004. One is an allele at the complex Rrs1 locus on chromosome 3H close to the centromere; the other is located 22 cM distally on the long arm. The latter locus is designated Rrs4. In BC3-lines into Ingrid from CI 2222 (another Nigrinudum) resistance seems governed by one locus close to the telomeric region of chromosome 7H, probably allelic to Rrs2. In neither case did we find any trace of the recessive gene rh8 reported to be present in Nigrinudum. Various resistance donors of Ethiopian origin designated as Nigrinudum, Jet or Abyssinian were identical to a great extent with respect to markers, but differed in resistance to different isolates of scald or in barley yellow dwarf virus (BYDV) resistance. The implications for their use as differentials in scald tests and screening of germplasm collections are discussed. 相似文献
20.
The component spectra (maxima of absorption, circular and linear dichroism) of individual chromophores have been assigned for phycoerythrocyanin (PEC) trimer, monomer(s), and its subunits (-PEC and -PEC) by titration with p-chloromercury-benzene-sulfonate (PCMS), linear dichroism and photochemical transformations, as well as by deconvolution using a bilin line-shape spectrum based on the -84 phycoviolobilin-chromophore in the -subunit. The level ordering PVB--84 PCB--155 PCB--84 is the same irrespective of aggregation. Two different monomers () were observed. In 4 M urea, the spectra are appropriately weighted sums of the subunit spectra, whereas in the monomer obtained in 1 M KSCN, both -chromophores are red-shifted by 4–5 nm. Formation of trimer ()_3gives considerable spectral changes: (1) the absorption is narrowed, which has been rationalized by excitonic coupling between neighbouring monomers, (2) the short wavelength part in the CD spectrum is missing and (3) a fourth band (+) at 528 in the LD spectrum appears. A deconvolution of the trimeric aggregation state using only the bilin line-shape model is not possible. 相似文献