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1.
Of 147 microorganisms isolated from a loamy sand, 71 showed good growth with lindane (-1,2,3,4,5,6-hexachlorocyclohexane) and produced chloride in an aqueous medium. Thirteen soil microorganisms were selected to study the utilization of lindane. Lindane was metabolized by the microbes to -2,3,4,5,6-pentachloro-1-cyclohexene (-PCCH), -3,4,5,6-tetrachloro-1-cyclohexene (-TCCH), -3,4,5,6-tetrachloro-1-cyclohexene (-TCCH), -3,4,5,6-tetrachloro-1-cyclohexene (-TCCH), and pentachlorobenzene (PCB). Cells of Pseudomonas sp. No. 62 grown on lindane simultaneously adapted to -PCCH, -TCCH, -TCCH, -TCCH, PCB, 1,2,3,4-tetrachlorobenzene (1,2,3,4-TCB) and 1,2,4,5-tetrachlorobenzene (1,2,4,5-TCB). The bacteria degraded each of these chemicals at least partially as indicated by an increased rate of oxygen consumption.Abbreviations Lindane -1,2,3,4,5,6-hexachlorocyclohexane - -PCCH -2,3,4,5,6-pentachloro-1-cyclohexene - -TCCH -3,4,5,6-tetrachloro-1-cyclohexene - -TCCH -3,4,5,6-tetrachloro-1-cyclohexene - -TCCH -3,4,5,6-tetrachloro-1-cyclohexene - PCB pentachlorobenzene - 1,2,3,4-TCB 1,2,3,4-tetrachlorobenzene - 1,2,3,5-TCB 1,2,3,5-tetrachlorobenzene - 1,2,4,5-TCB 1,2,4,5-tetrachlorobenzene - 1,2,3-tCB 1,2,3-trichlorobenzene - 1,2,4-tCB 1,2,4-trichlorobenzene - 1,3,5-tCB 1,3,5-trichlorobenzene - 1,2-DCB 1,2-dichlorobenzene - 1,3-DCB 1,3-dichlorobenzene - 1,4-DCB 1,4-dichlorobenzene - MCB monochlorobenzene Contribution No. 631, Research Institute, Agriculture Canada, University Sub Post Office, London, Ontario N6A 5B7  相似文献   

2.
Summary The histochemical activities of succinic dehydrogenase (SDH), myofibrillar Adenosine triphosphatase (ATPase) and alpha glycerophosphate dehydrogenase were studied in serial sections of rat vastus lateralis (red) (RVL), gastrocnemius and diaphragm muscles. Three main fibre-types were distinguished. The Type I fibres of RVL and gastrocnemius muscles fell into two distinct groups: one category-Type IA showed very low ATPase activity. The second category of Type IB fibres displayed moderate ATPase reaction. The Type IA fibres were divisible into two sub-groups when tested for SDH reaction. Type IA1 fibres possessed a homogenous distribution of diformazan·granules throughout the fibre: Type IA2 fibres displayed characteristic moth-eaten pattern of diformazan localization. The diaphragm muscle did not show either Type IB or Type IA2 varieties. The great majority of Type I fibres were sub-type IA1 in the three fast muscles studied. It is also demonstrated here that an inherent heterogeneity exists between Type I fibres of diaphragm and leg muscles in regard to -GPD localization. This histochemical data emphasizes the fact that subdivision of Type I striated muscle fibres of mammalian animals into two sub-types is only approximate and that a further subcategorization is possible.  相似文献   

3.
The pericentric chromatin of chromosome 18 was found to be far more heterogeneous for restriction endonuclease AluI (5 ··· AG CT···3) than previously thought. The extent of such heterogeneity was characterized using 50 normal Caucasians and 5 cases of trisomy 18 or Edwards' Syndrome. The AluI-resistant chromatin can arbitrarily be classified into at least five sizes by comparison with the length of the short arm (p) of chromosome 18. They are: negative (1), small (2), medium (3), large (4) and very large (5) with incidences of 11.30%, 19.13%, 29.57%, 29.57% and 10.43%, respectively. In addition the location of the chromatin can be classified into four types depending upon the position relative to the primary constriction. For example: Type I (absent); Type II (present on p arm only); Type III (present on q arm only); Type IV (present on centromere and extending into both p and q arms). The incidences of types I, II, III, and IV were 11.30%, 62.61%, 0.87%, and 25.22%, respectively. Based on limited data, AluI-resistant chromatin was found to be predominantly large and very large in Edwards' Syndrome samples. In addition, no case with negative Alu-resistant chromatin was noted. Therefore, it is tempting to speculate that the amount of chromatin present on the centromere might play a role in non-disjunction in Edwards' Syndrome cases. Although the variation observed in the present study is continuous, the proposed classification has some important implications for future investigations.  相似文献   

4.
Embryonic, larval, and juvenile development of an Indian cyprinid fish, Chela dadiburjori, is described from laboratory-reared specimens. The eggs, measuring 0.7–0.9mm in diameter, were demersal, almost spherical in shape, transparent and unpigmented, with a pale yellow yolk and no oil globule. Hatching occurred 50–61h after fertilization at ca. 27°C. The newly hatched larvae, measuring 2.4–2.6mm in body length (BL), had melanophores on the body with 14–16+14–17=29–31 myomeres. Two dark transverse bands on the ventral body surface and one melanophore on the lower margin of the eye in newly hatched larvae were diagnostic. Additionally, a cement organ for adhering to objects was present on the forehead of yolk sac larvae <3.1mm BL. The yolk was completely absorbed at 3.5mm BL. Notochord flexion was initiated at 5.0mm BL and finished at 6.0mm BL. Aggregate numbers of all fin rays were completed at 9.2mm BL. Squamation was initiated on the caudal peduncle at 8.0mm BL and completed at 10mm BL. The eggs of C. dadiburjori resembled those of the closely related species Devario malabaricus and Danio rerio. The larvae and juveniles of C. dadiburjori were also similar to those of the latter species in general morphology, especially the presence of body melanophores in newly hatched individuals and a distinctive lateral streak on the head during the period from yolk sac to postflexion larvae. However, early yolk sac larvae of C. dadiburjori were more similar to those of Devario malabaricus than Danio rerio in having a cement organ on the forehead. Larvae and juveniles of C. dadiburjori differed from those of the latter two species in pigmentation on the ventral body surface at hatching and around the mouth during the period from preflexion to early postflexion larvae and in having a dark lateral streak or band on the body in postflexion larvae and juveniles.  相似文献   

5.
A standard pachytene karyotype of chickpea (Cicer arietinum L.) is presented for the first time. Individual pachytene chromosomes were identified and described in detail. An idiogram was prepared on the basis of chromosome length, arm ratio, and distribution of heterochromatin and euchromatin. Chickpea pachytene chromosomes belong to the differentiated type with darker staining heterochromatin proximal to and lighter staining euchromatin distal to the centromeres. Chromosomes were numbered from 1 to 8 following a descending order of length. The total length of the chromosome complement at pachytene was 335.33 , and chromosome size ranged from 58.05 to 30.53 .  相似文献   

6.
Cerebellar granule cells (CGC) at different stages of maturation in vitro (1 or 6 DIV), were treated with 25–35 and acetyl-L-carnitine arginine amide (ST857) in presence of 25 mM KC1 in the culture medium, and neuronal viability was assessed. Three days of treatment slightly modified the survival of 1 DIV-treated cells, which degenerate and die five days later -amyloid matching. Similarly, a significative neurotoxic effect was observed on 6 DIV treated-cells after 5 days of exposure to the peptide, while the death occurred within 8 days. ST857 coincubated with 25–35 was able to rescue neurons from 25–35-induced neurotoxicity. We also studied the changes in Ca2+ homeostasis following glutamate stimulation, in control and -amyloid treated single cells, either in presence or in absence of ST857. 25–35 did not affect basal [Ca2+]i, while modified glutamate-induced [Ca2+]i increase, causing a sustained plateau phase of [Ca2+]i, that persisted after the removal of the agonist. ST857 pretreatment completely reverted this effect suggesting that, in CGC chronically treated with 25–35, ST857 could protect the cells by neurotoxic insults of the peptide likely interfering with the cellular mechanisms involved in the control of Ca2+ homeostasis.  相似文献   

7.
Shoot regeneration from seed-derived callus cultures of Kentucky bluegrass (Poa pratensis L.) was tested on MS basal medium supplemented with four different growth regulators. Regeneration frequencies for medium supplemented with 10 M 2,4-dichlorophenoxyacetic acid (2,4-D), 60 M 4amino-3, 5,6-picolinic acid (picloram), or 30 M 3,6dichloro-o-anisic acid (dicamba) ranged from 0.4 to 4%. Medium supplemented with 30 M dicamba plus 10 M 6-benzylaminopurine (BA) resulted in regeneration of shoots from 20% of the calli tested. Higher rates of growth regulators (60 or 90 M dicamba, 20 M BA) resulted in regeneration of shoots from 45% of calli of the cultivar Baron. In a subsequent study, the response of 12 North American cultivars grown on these media was cultivar-specific, with mean frequencies of regeneration ranging from 4% to 40%.Abbreviations 2,4-D 2,4-dichlorophenoxyaceticacid - dicamba 3,6-dichloro-o-anisic acid - picloram 4-amino-3,5,6-picolinic acid - BA 6-benzylaminopurine  相似文献   

8.
Autopsied liver tissue samples collected from 42 males and 31 females were analyzed for copper, manganese and zinc using atomic absorption spectrometry (AAS). With the exception of two liver samples for which the copper levels were determined to be 74.8 and 104.0 g/g (dry weight), hepatic copper concentrations were found to range from 1.7 to 32.4 g/g with a mean concentration of 14.2 g/g and standard deviation of 7.0 g/g. Manganese concentrations (with the exception of one sample having 12.9 g/g) ranged from 0.22 to 4.6 g/g with a mean of 2.26 ± 1.00 g/g. Hepatic zinc levels averaged 118.3 ± 44.4 g/g and ranged from 38.5 to 231.3 g/g. There were no apparent trends for the levels of any metals versus age nor were there any differences in average hepatic metal concentrations for males and females. © Rapid Science 1998.  相似文献   

9.
Summary The non-tandem inverted duplication in the 2-m DNA of Saccharomyces cerevisiae has a length of 0.19 m and is located asymmetrically along the molecule. The majority of the dumb-bell structures that are formed upon denaturation and selfannealing of the 2-m monomer consists of the renatured inverted duplication sequences as double stranded stem and two single stranded loops of 0.67 m±0.06 m (S-loop) and 0.86 m±0.05 m (L-loop) length. Two additional size classes which comprised 5–10% of the measured molecules had contour lengths of around 1.7 m and 2.1 m. The smaller dumb-bells contained two S-loops and the larger dumb-bells contained two L-loops as was shown by heteroduplex mapping with an HindIII fragment from the L-loop. Two models which assume illegitimate or site specific recombination, are presented to explain the generation of double S-loop and double L-loop molecules. At least part of the 4-m and 6- circular molecules present in the yeast supercoiled DNA fraction are shown to be dimers and trimers of 2-m monomers, but often with inverted loop segments most probably due to intramolecular recombination between sequences of the inverted duplication.2-m DNA is used to indicate the supercoiled DNA fraction although in our measurements the average monomeric length is 1.9 mPart of this work has been presented at the Conference: The Genetics and Biogenesis of Chloroplasts and Mitochondria, Munich, August, 1976  相似文献   

10.
Integrin 5 1 and 2 1 are the major integrin receptors in human hepatocytes. However, in human hepatocellular carcinoma cells it was found that the expression of integrin 5 1 was decreased and another integrin 6 1 increased. In this study, the SMMC7721 human hepatocellular carcinoma cells cotransfected or singlely transfected with integrin 5 and/or 1 cDNAs were established, and designated 5 1.6-7721, 5.3-7721, and 1.6-7721 cell lines, respectively. Transfection with cDNAs of integrin 5 and 1 subunits resulted in the overexpression of each integrin and modified biological properties, including a slowed growth rate, changes in the cell cycle from 15.5% of control cells in the G2/M phase to 12.1%, 9.6% and 9.4% in 5.3-7721, 1.6-7721, 5 1.6-7721, respectively, and a decrease in the Cell Mitosis Index from 1.6 in controls to 0.96, 0.95, and 0.72, and 34%, 28% and 52% derived from colony forming ability, respectively. Tumorigenicity was also tested in nude mice with inoculation of cells subcutaneously. Tumor masses growing in nude mice following inoculation with 1.6-7721,and 5 1.6-7721 cells weighed only 52% or 31% those of control cells. These results indicated that deletion or low expression of integrin 5 1 may play an important role in the development of hepatocellular carcinoma. Therefore, induction of expression of the integrin 5 1 in malignant cells could be a potential means of treating hepatocellular carcinoma.  相似文献   

11.
Glycolipids of peripheral leukocytes which had been used for the production of interferon were separated into oligoglycosylceramides, polyglycosylceramides and polyglycosylpeptides (erythroglycan). Neutral oligoglycosylceramides comprised glucosylceramide, galactosylceramide, lactosylceramide, lactotriaosylceramide, globotriaosylceramide andneolactotetraosylceramide. Globotetraosylceramide was not detected. Glycolipids which were more complex thanneolactotetraosylceramide belonged exclusively to theneolacto series of compounds and were essentially unbranched at galactopyranosyl residues. The polyglycosylceramide fraction contained a glycolipid with a probable structure Gal1-4(Fuc1-3) GlcNAc1-3Gal1-4GlcNAc1-3 Gal1-4GlcNAc1-3Gal1-4Glc1-1ceramide. Polyglycosylpeptides were found only in trace amounts and were also unbranched at galactopyranosyl residues. All glycoconjugates studies did not contain significant amounts of carbohydrate structures derived from ABH immunodominant groups.Nomenclature Gal1-4Gal1-4GlcCer Lactotrioasylcermide (LcOse3Cer) - Gal1-4Gal1-4GlcCer globotriaosylceramide, (GbOse4Cer) - GalNAc1-3Gal1-4 Gal1-4GlcCer globoside (globotetraosylceramide, GbOse4Cer) - Gal1-4GlcNAc1-3Gal1-4GlcCer paragloboside (lacto-N-neo tetraosylceramide,nLcOse4Cer)  相似文献   

12.
Summary The ratio of deuterium to hydrogen (expressed as D) in hydrogen released as water during the combustion of dried plant material was examined. The D value (metabolic hydrogen) determined on plant materials grown under controlled conditions is correlated with pathways of photosynthetic carbon metabolism. C3 plants show mean D values of-132 for shoots and -117 for roots; C4 plants show mean D values of -91 for shoots and-77 for roots and CAM plants a D value of-75 for roots and shoots. The difference between the D value of shoot material from C3 and C4 plants was confirmed in species growing under a range of glasshouse conditions. This difference in D value between C3 and C4 species does not appear to be due to differences in the D value (tissue water) in the plants as a result of physical fractionation of hydrogen isotopes during transpiration. In C3 and C4 plants the hydrogen isotope discrimination is in the same direction as the carbon isotope discrimination and factors contributing to the difference in D values are discussed. In CAM plants grown in the laboratory or collected from the field D values range from-75 to +50 and are correlated with 13C values. When deprived of water, the D value (metabolic hydrogen) in both soluble and insoluble material in leaves of Kalanchoe daigremontiana Hamet et Perr., becomes less negative. These changes may reflect the deuterium enrichment of tissue water during transpiration, or in field conditions, may reflect the different D value of available water in areas of increasing aridity. Whatever the origin of the variable D value in CAM plants, this parameter may be a useful index of the water relations of these plants under natural conditions.  相似文献   

13.
Summary The distribution of -tubulin throughout cell division is studied in several taxa of higher plants. -Tubulin is present along the whole length of microtubules (Mts) in every cell stage-specific Mt array such as the preprophase band, the preprophase-prophase perinuclear Mts, the kinetochore Mt bundles, the phragmoplast, and the telophase-interphase transition Mt arrays. -Tubulin follows with precision the Mt pattern, being absent from any other, Mt-free, cell site. In cells treated with anti-Mt drugs, -tubulin is present only on degrading or on reappearing Mt arrays, while it is totally absent from cells devoid of Mts. -Tubulin is also present in tubulin paracrystals, which are formed in colchicine-treated cells. These observations support the view that in higher plants -tubulin may not be a microtubule-organizing-center-specific protein, but it may play a certain structural and/or functional role being related to - and -tubulin.Abbreviations Mt microtubule - MTOC microtubule-organizing center - PPB preprophase band  相似文献   

14.
Early-stage morphologies of the mandarinfish Siniperca chuatsi are described on the basis of an ontogenetic series of reared specimens in an aquarium. Spherical eggs (diameter 1.70–1.82mm) with a single oil globule (0.40–0.48mm) were free-demersal and easily floated when agitated. Hatching occurred about 3 days after spawning at about 24°C. Newly hatched larvae (3.8–4.2mm in notochord length: NL) had many melanophores on the yolk sac. After reaching ca. 5.5mm NL (8–9+19–20=27–28 myomeres), larvae had almost completely absorbed the yolk, possessed a large mouth and sharp teeth, and were starting to prey on other fish larvae. Three large preopercle spines appeared at ca. 5.5mm NL, five spines by ca. 8.5mm NL, and eight by ca. 21mm in standard length (SL). The interopercle bore a single spine at ca. 8.5mm NL and two spines at ca. 13.5mm SL. A single spine appeared at the supracleithrum and another at the opercle at ca. 10mm SL. Dorsal fin spines and pelvic, anal, and caudal fins were completed at ca. 10mm SL. Dorsal fin rays and pectoral fins were completed at ca. 13.5mm SL. Four ontogenetic characters (free-demersal eggs, large jaws with large teeth, conspicuous head spination, and precocious completion of dorsal fin spines) are rare among freshwater percoids.  相似文献   

15.
Summary Zoospores derived from ordinary colorless plants ofBlastocladiella emersonii grown under 240 W/cm2 of visible light contain an average of ca. 5 -particles and numerous aggregates of cytoplasmic granules which resemble the -matrix, while spores from dark-grown plants contain ca. 12 -particles but none of the granules. Correspondingly, the amount of chitin synthetase associated with -particles is approximately proportional to the number of -particles in the two spore types. The foregoing light effects, known to be accompanied by an increased capacity for encystment, probably take place before sporogenesis. Conversely, zoospores derived from dark-grown plants do not encyst appreciably over an 8 h period unless they are illuminated, but the number of -particles/spore decreases from 12 to ca. 6 whether or not light is present. Arguments are presented for considering the latter disappearance of -particles as an essential ark reaction which precedes a photochemical reaction, both being needed for light-induced encystment.  相似文献   

16.
Apostichopus (= Stichopus) japonicus blastulae and gastrulae were acclimated for 18 h to salinities of 32 (control), 24 and 22 (the lower limit of the range of tolerance), and 20 (below the range of tolerance). Acclimation to 20 resulted in the appearance of teratic larvae, most of which subsequently died. Acclimation to 24, 22, and 20 led to a shift in the range of tolerance of the larvae at further stages of development. With a decrease in salinity, acclimated larvae developed more successfully than unacclimated larvae. Acclimated larvae attained the pentactula stage and settled at a salinity range of 32–20; unacclimated larvae, at 32–22. At different stages of development, acclimated larvae survived greater decreases in salinity than unacclimated larvae. The acclimation effects could be traced up to metamorphosis and settling, i.e., two weeks after the end of the acclimation process.  相似文献   

17.
Alzheimer's disease is the most prevalent form of dementia worldwide. Therapies are desperately needed to prevent and cure the disease. Mouse models of amyloid- deposition [APP and PSAPP transgenic (tg) mice] have been useful in determining the role of amyloid- (A) in both the pathogenesis and cognitive changes in AD. In addition, they have allowed scientists to investigate potential AD therapies in living animals. Active and passive A immunizations have been employed successfully in APP and PSAPP tg mice to lower cerebral A levels and improve cognition. Optimization of immunization protocols and characterization of immune responses in wildtype mice have been reported. Based on the promising results of A immunization studies in mice, a clinical trial was initiated for A vaccination in humans with AD. Although no adverse effects were reported in the Phase I safety trials, about 5% of AD patients in the phase II clinical trial developed meningoencephalitis, ending the trial prematurely in March 2002. Studies in AD mouse models and wildtype mice may help elucidate the mechanism for these unwanted side effects and will be useful for testing newer, safer vaccines for future use in human clinical trials.  相似文献   

18.
Summary Ground leaf litter was inoculated with the fungus Coriolus versicolor and incubated in respirometers for 6 days (fresh cultures) or 33 days (senescent cultures) before different number of Folsomia candida were added. Grazing by 5 animals stimulated O2 consumption in both series of cultures but 10, 15 or 20 animals inhibited microbial respiration. The stimulatory effect was less marked in the senescent cultures. Bacterial and fungal standing crops increased in fresh cultures during the course of the experiment but grazing by collembola increased bacterial and reduced fungal standing, crops in proportion to the grazing intensity. Microbial standing crops were not determined for senescent cultures. Microarthropod feeding activities can therefore exert a strong differential effect on fungal and bacterial populations which has not been previously recognised.  相似文献   

19.
Tumor necrosis factor and interleukin-1 increase surfactant secretion in type II pneumocytes in a time- and dose-dependent manner. This stimulatory effect was additive to that of lipopolysaccharide, suggesting that cytokines and lipopolysaccharide may exert their actions through different signal transduction pathways. Tumor necrosis factor and interleukin-1 did not modify the increase on phosphatidylcholine secretion induced by the direct protein kinase C activator tetradecanoylphorbol 13-acetate, whereas this effect was inhibited by the protein kinase C inhibitors bisindolylmaleimide (2 × 10-6M) and 1-(5-isoquinolinylsulphonyl)-2-methyl piperazone (10-4M). In addition, the stimulatory effect of tumor necrosis factor and interleukin-1 was not suppressed by the intracellular Ca2+ chelator BAPTA (5 × 10-6M) or by KN-62 (3 × 10-5M), a specific inhibitor of Ca2+-calmodulin-dependent protein kinase. These results suggest that tumor necrosis factor or interleukin-1 stimulate phosphatidylcholine secretion via protein kinase C activation in a Ca2+ -independent manner.  相似文献   

20.
Theaflavins were synthesized from tea polyphenols extracted from green tea using an immobilized polyphenol oxidase system. To optimize the production of theaflavins, response surface methodology was applied to determine the effects of five critical variables and their mutual interactions on theaflavin biosynthesis at five levels. A total of 52 individual experiments were performed and a statistical model predicted that the highest theaflavin concentration was 0.766mgml–1 at optimized conditions. Using these optimal parameters under experimental conditions in three independent replicates, the average value of the biosynthesized theaflavin concentration reached 0.75±0.017mgml–1 and matched the value predicted by the modelRevisions requested 03 November 2004; Revisions received 7 December 2004  相似文献   

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