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1.
Summary We report the delignification ofPinus radiata D Don,Eucalyptus globulus andEucalyptus grandis woods (formic acid treated and untreated) by 2 h treatment with a hemin/hydrogen peroxide system. The untreated chips and sawdust ofE. globulus were 30% and 50% delignified respectively. No significant effects were found forP. radiata sawdust;P. radiata treated chips (organosolv pulp) did not show any further delignification upon hemin/peroxide action, 25% delignification was achieved in untreated chips. In the case ofE. grandis untreated wood the delignification was better in sawdust than in chips, but in smaller percentage than in the otherEucalyptus species. This relation is maintained in substrates, treated with formic acid or untreated. The delignification of chips in both species ofEucalyptus was improved when they were pre-treated with formic acid. The loss of lignin in theE. grandis andE. globulus sawdust (pre-treated with formic acid) was 79% and 75% respectively.  相似文献   

2.
Summary Dotted (Dt) is the regulatory element of a two-unit controlling system in maize. Dt causes the inherited change from the recessive a (colorless) to its dominant allele, A (anthocyanin production), during the development of the stalk, leaves, and endosperm. The mutation events are observed as sectors of color in an anthocyaninless background.Since its discovery over 40 years ago, Dt has always been found in the terminal knob of the short arm of chromosome 9. This is puzzling because controlling and regulatory elements in general are not located permanently, but change positions (transpose) within the chromosomal complement. To resolve this seeming discrepancy, transpositions were looked for in a homozygous a Dt stock. Because the frequency of aleurone mutations is exponentially related to Dt dosage, a Dt transposition would result in a greatly increased number of dots if the egg or sperm nucleus contained both the transposed Dt and the Dt remaining on chromosome 9. A total of 6 transposed Dt's (Dt-T) were recovered in this manner. Dt-TA was found linked to the gene Y (yellow endosperm) of chromosome 6. Dt-TB no longer showed linkage with yg2 of chromosome 9, but remains unlocated (the original Dt in this stock is separated from yg2 by 6 or 7 cross-over units.). The remaining transpositions (C-F) assorted independently of Dt on chromosome 9.The transposed Dt's had the same effect as Dt on the frequency and timing of aleurone mutations. An increase in transposition frequency and losses of Dt-T's was characteristic of several of the transposed Dt's. Dt-T's B-F transposed so frequently that testcross ratios of 71 (three Dt' s) and 15 1 (four Dt' s) were observed. No secondary transpositions or losses of Dt-TA were detected. Thus, Dt-TA resembles the original Dt with regard to its transposition frequency and stability.Journal Paper No. J-8333 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1880.  相似文献   

3.
Summary A total of 55 yeast strains selected from 7 genera known to ferment carbohydrates to ethanol were screened for their ability to ferment glucose to ethanol in shaken flask culture at 37°, 40° and 45°C. Yields of more than 50% of the theoretical maximum were obtained with 28 strains at 37°C, but only 12 at 40°C. Only 6 could grow at 45°C, but they produced poor yields. In general Kluyveromyces strains were more thermotolerant than Saccharomyces and Candida strains, but Saccharomyces strains produced higher ethanol yields. The 8 strains with the highest yields at 40°C were evaluated in batch fermentations. Three of these, two Saccharomyces and one Candida, were able to meet minimum commercial targets set at 8% (v/v) ethanol from 14% (w/v) glucose at 40°C.  相似文献   

4.
One-dimensional (1D) simulation of the complete vascular network, so called THINkS (Total Human Intravascular Network Simulation) is developed to investigate changes of blood flow characteristics caused by the variation of CoW. THINkS contains 158 major veins, 85 major arteries, and 77 venous and 43 arterial junctions. THINkS is validated with available in vivo blood flow waveform data. The overall trends of flow rates in variations of the CoW, such as the missing anterior cerebral artery (missing-A1) or missing posterior cerebral artery (missing-P1), are confirmed by in vivo experimental data. It is demonstrated that the CoW has the ability to shunt blood flow to different areas in the brain. Flow rates in efferent arteries remain unaffected under the variation of CoW, while the flow rates in afferent vessels can be subject to substantial changes. The redistribution of blood flow can cause particular vessels to undergo extra flow rate and hemodynamic stresses.  相似文献   

5.
Summary Four cultures of white rot fungi were screened for their ability to degrade lignin and carbohydrates of sugarcane bagasse and their effect on changes inin vitro digestibility.Polyporus hirsutus534 degraded maximum lignin and carbohydrates accompanied with the highest increase in digestibility, but increase in nutrient availability was maximum withPleurotus sajorcaju (Z-6) due to lower dry matter loss during the process of fungal treatment. All the fungi tested exceptPolyporus caperatus Berk. degraded lignin more selectively than the other components of sugarcane bagasse.  相似文献   

6.
Catechol-O-methyltransferase (COMT) is an important modulator in the catabolism of extraneural dopamine, which plays an important role in drug reward mechanisms. It is hypothesized that genetic variations in the COMT gene, which can result in a three to fourfold difference in COMT enzyme activity, may be associated with several reward-motivated behaviors. The aim of our study was to examine the relationship between COMT polymorphisms with smoking, obesity and alcohol. Three single nucleotide polymorphisms (SNPs) in COMT were genotyped in 2,371 participants selected randomly from the screening arm of the PLCO Cancer Screening Trial after stratifying by sex, age, and smoking status. Smoking, obesity, and alcohol consumption were assessed by questionnaire. SNP and haplotype associations were estimated using odds ratios (ORs) and 95% confidence intervals (CIs) derived from conditional logistic regression models, adjusted for race/ethnicity. The COMT Ex4-76C > G (Leu136Leu) polymorphism was statistically significantly associated with individuals who had >30% increases in BMI from ages 20 to 50 years, compared to those with 0–5% increase in BMI (0–5%) over the same age period: (CC is referent; ORCG = 1.42, ORGG = 1.46, P trend = 0.06). By sex, the increased risk was further pronounced among females (ORCG = 1.50, ORGG = 2.10, P trend = 0.03). Consistent with our analyses of single polymorphisms, individuals whose BMI increased >30% from ages 20 to 50 years were more likely than individuals with 0–5% increases in BMI to possess COMT haplotypes [COMT Ex3-104C > T–COMT Ex4-76 C > G–COMT Ex4-12 A > G] that included the variant allele for COMT Ex4-76 C > G: C-G-G (T-C-A is referent: ORC-G-G = 1.33, 95% CI 1.01–1.77) and C-G-A (ORC-G-A = 1.79, 95% CI 0.72–4.49). We observed no association between any of the COMT polymorphisms with smoking behavior or alcohol intake. The COMT Ex4-76C > G (Leu136Leu) polymorphism appears to play a role in large increases in BMI. The null association with smoking and alcohol and the pronounced association with increasing BMI among women further implicates COMT’s role in estrogen metabolism as a potentially culpable pathway. Our results support a need for comprehensive evaluation of COMT variations and their functional relevance as COMT may be an important molecular target to evaluate for new treatments regarding obesity.  相似文献   

7.

Background  

The 'lid' subcomplex of the 26S proteasome and the COP9 signalosome (CSN complex) share a common architecture consisting of six subunits harbouring a so-called PCI domain (proteasome,CSN, eIF3) at their C-terminus, plus two subunits containing MPN domains (Mpr1/Pad1N-terminal). The translation initiation complex eIF3 also contains PCI- and MPN-domain proteins, but seems to deviate from the 6+2 stoichiometry. Initially, the PCI domain was defined as the region of detectable sequence similarity between the components mentioned above.  相似文献   

8.
A study of shoot regeneration from cotyledons of three basic diploid species of Brassica, B. campestris (AA), B. nigra (BB), B. oleracea (CC) and their amphidiploids B. juncea (AABB), B. napus (AACC) and B. carinata (BBCC) showed species-specific responses for in vitro shoot regeneration. Analysis of the species mean shoot regeneration response over a range of growth regulator combinations revealed that i) B. campestris is the lowest regenerating species, ii) B. nigra and B. oleracea regenerate with high frequencies, iii) In amphidiploids, the presence of B. campestris component brings down shoot regeneration frequency below the value of B. oleracea in B. napus combination and is additive of the combining genomes in B. juncea combination. In B. carinata regeneration frequencies are less than the parental diploid species, iv) Significant intraspecific genotypic differences were observed for B. nigra and B. oleracea among diploids and B. juncea and B. carinata among amphidiploids, when cotyledons of eighteen genotypes were tested in one growth regulator combination.Abbreviations MS Murashige and Skoog (1962) - NAA -naphthalene acetic acid - IAA Indole 3-acetic acid - BA 6-Benzyl aminopurine  相似文献   

9.
Cultured protoplasts from cell suspensions of Pelargonium aridum, P.x hortorum and P. peltatum divided and formed callus. On agar-solidified regenerative medium, such protoplast-derived calli (p-calli) underwent plant regeneration at frequencies approaching 100% for P. aridum and 10% for P.x hortorum. Under similar conditions shoot primordia arose in 5% of P. peltatum p-calli, but these never developed into normal shoots. However, following a liquid-shake culture regime, whole plants were induced in 20% of P. peltatum p-calli. This approach also improved regeneration of P.x hortorum to 60%.Abbreviations NAA napthaleneacetic acid - 6-BAP 6-benzylaminopurine  相似文献   

10.
Interspecific somatic hybrid plants betweenRudbeckia hirta cv. Marmalade andR.laciniata cv. Irish Eyes were regenerated following the electro-fusion of mesophyll protoplasts ofR.hirta with callus protoplasts ofR.laciniata. A hybrid selection scheme was based on the fact that plant regeneration, from parental protoplasts ofR.hirta, was via shoot regeneration of callus, and only via rhizogenesis forR.laciniata. The other half of the selection strategy was based on the presence of anthocyanin-pigmented roots; a characteristic of theR.hirta parent only. Somatic hybrids were regenerated, via rhizogenesis, alongside normalR.laciniata but were distinguished by the presence of pigmented roots (a feature ofR.hirta). Hybrid plants had a floral morphology that was intermediate as compared to that of the two parents, with an expected somatic chromosome number of 2n=(2x+4x)=74. Pollen viability though was low. Esterase and peroxidase isozyme profiles confirmed the hybrid nature of the regenerated plants with pigmented roots, whilst chloroplast DNA restriction analysis showed that these hybrids had aR.laciniata chloroplast DNA. This demonstration of somatic hybridisation not only opens up the possibility of incorporating novel traits between such ornamentalCompositae species, but provides a selection strategy based on rhizogenesis as the route to plant regeneration coupled with heritable pigmentation production of roots as a confirmatory hybrid marker.ABBREVIATIONS BSA bovine serum albumin - EDTA ethylene diamine tetra acetic acid - FDA fluorescein diacetate - f.wt. fresh weight - IAA indole 3-acetic acid - MS Murashige and Skoog (1962) medium - TEMED N,N,N,N-Tetra methyl ethylene diamine - TES (N-tris (hydroxymethyl) methyl-2-aminoethanesulfonic acid)  相似文献   

11.
Reverse micelle extraction is still in the stage of laboratory. Major limitation associated with use of synthetic surfactants in reverse micelle extraction process is the unfolding or denaturation of proteins. Sugar surfactants are thought non-toxic and environmentally benign, and can exhibit interesting interfacial properties, but the application of sugar-based surfactants in protein extraction is still limited. In the present study, we extracted bovine serum albumin (BSA) by using reverse micelles from glucosylammonium (GA) and lactosylammonium (LA) surfactants (with dicarboxylate as counter ion). It was found that under optimum condition, (1) the maximum forward extraction efficiency was ca. 86% with GA, while only around 50% with LA, and (2) almost all BSA solubilized in reverse micelles prepared from GA could be recovered into aqueous phase, while the recovery of BSA from the reverse micelles of LA was lower. In addition, the optimum extraction parameters were closely related to surfactant structure. Therefore, the electrostatic interaction, H-bonding and sugar head size should be important for BSA transfer.  相似文献   

12.
One evidence for a luteolytic role for prostaglandin F2α in the human is the increase in luteal PGF at times corresponding to luteolysis as reported earlier by us and other groups. There have been other contradictory reports on this point. In the present experiments we have measured the concentrations of PGE and PGF in 16 more human corpora lutea and have determined the capacity of those tissues to form PGE and PGF in vitro. PGF concentrations were highest in the mid luteal phase but were accompanied by high PGE concentrations. On the other hand, in the late luteal phase PGF concentrations, lower than in mid luteal but generally higher than in early luteal phase, were significantly higher than PGE concentrations. This pattern in PGE and PGF concentrations was also evident in the capacity of these tissues to form these compounds in vitro. In view of the known capacity of PGE2 to counteract the luteolytic effect of PGF2α, these variations in the relative concentrations of PGE and PGF during the luteal phase may be of significance in the process of luteolysis in the human.  相似文献   

13.
Summary Cultures ofStr. thermophilus assimilated less cholesterol than those ofLactobacillus delbrueckii subsp.bulgaricus. A significant difference was found between strains ofL. delbrueckii subsp.bulgaricus — LB1 and LB2 and LB3 (p<0.001).Bif. bifidum actively assimilated cholesterol, but no significant difference was observed between their two strains (p>0.05). Cultures ofL. asidophilus assimilated significantly more cholesterol than those ofStr. thermophilus and a commercial yoghurt culture.  相似文献   

14.
Microscopic observations made during preparation of protoplasts and vacuoles from red radish seedling hypocotyl (Raphanus sativus L.) show that anthocyanoplasts, the strongly pigmented bodies present in the pigmented cells of the hypodermis, begin as apparently membranous vesicles in the cytoplasm made visible by the deposition and accumulation of anthocyanins, but only rarely appear in the isolated vacuole. Isolation of protoplasts and vacuoles was also achieved from mung bean seedling hypocotyl (Vigna radiata L Wilczek), red cabbage leaf (Brassica oleracea L.) and Prunus x yedoensis Matsum callus. Anthocyanoplasts were usually in the vacuole, although sometimes in the cytoplasm, of the mung bean and cabbage, but were never seen in vacuoles of Prunus callus.  相似文献   

15.
Comparative shoot regeneration responses of three diploid Brassica species, B. campestris (AA), B. nigra (BB) and B. oleracea (CC) and their synthetic amphidiploid combinations have been investigated. The study indicates that A genome has an inhibitory effect on regeneration as evident from significantly low responses of B. juncea (AABB) and B. napus (AACC) combinations, in comparison with regeneration response of B. nigra and B. oleracea. This inhibition may arise from genomic interactions or from the B. campestris cytoplasm interacting negatively with the alien genome. Significant cytoplasmic influence on regenerability has been observed in B. carinata (BBCC) synthesised from reciprocal crosses of B. nigra and B. oleracea.Abbreviations MS Murashige and Skoog (1962) - IAA Indole-3-acetic acid - NAA -napthaleneacetic acid - BA 6-Benzylaminopurine  相似文献   

16.
Both cell suspension cultures of Thalictrum flavum and T. dipterocarpum were found to produce berberine (0.3 and 0.4 g/l, respectively) as a main alkaloid. Berberine production in the latter was markedly stimulated by 1-naphthaleneacetic acid in combination with 6-benzylaminopurine, whereas it was rather suppressed by the same auxin in the former. T. flavum cultures accumulated berberine and columbamine in the cells without releasing them into medium. On the other hand, T. dipterocarpum cultures released berberine into medium during the logarithmic growth phase, but thereafter accumulated all the berberine synthesized in the cells.Abbreviations LS Linsmaier and Skoog - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-naphthaleneacetic acid - IAA indole-3-acetic acid - IBA indole-3-butyric acid - BA 6-benzylaminopurine - TFG a culture strain of T. flavum ssp. glaucum - TDP a culture strain of T. dipterocarpum  相似文献   

17.
Axillary buds from 5 genotypes of mulberry belonging to 4 species were cultured on modified MS basal medium. A total of 30 media combinations were tried for all the genotypes. The response of axillary buds and the requirement for growth regulators varied with genotype. In Morus indica BAP (0.25–0.5 mg/l), and in M. alba and M. rotondifolia GA3 (0.5–1.0 mg/l)were found to induce sprouting. Two genotypes of M. bombycis, namely Schimanochi and Mizusawa, developed healthy shoots on the incorporation of 2,4-D (0.5–1.0 mg/l) and BAP (0.5–2.0 mg/l), respectively. IBA (0.5 mg/l), along with cytokinin/auxin/gibberellin, had no effect on bud growth but helped root induction. Shoots developed from the axillary buds were further multiplied as nodal explants. MS basal medium supplemented with 0.5 mg/l IBA and LS vitamins was found best to produce healthy plantlets in all the genotypes. An average 89% survival was observed on transferring the plantlets to soil.Abbreviations MS Murashige and Skoog (1962) - LS Linsmaier and Skoog (1965) - IBA 3-indole-butyric acid - GA3 Gibberellic acid - BAP 6-Benzylaminopurine - Kn Kinetin - 2,4-D 2,4-Dichlorophenoxyacetic acid  相似文献   

18.
Summary Three strains ofPichia stipitis and three ofCandida shehatae were compared withPachysolen tannophilus in their abilities to ferment xylose at concentrations as high as 200 g/L when subjected to both aerobic and microaerophilic conditions. Evaluations based on accumulated ethanol concentrations, ethanol productivities, xylose consumption, and ethanol and xylitol yields were determined from batch culture time courses. Of the strains considered,P.stipitis NRRL Y-7124 seemed most promising since it was able to utilize all but 7 g/L of 150 g/L xylose supplied aerobically to produce 52 g/L ethanol at a yield of 0.39 g per gram xylose (76% of theoretical yield) and at a rate comparable to the fastest shown byC.shehatae NRRL Y-12878. For all strains tested, fermentation results from aerobic cultures were more favorable than those from microaerophilic cultures.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.  相似文献   

19.
Soluble cytokine receptors are frequently found in human serum, most of them possessing antagonistic properties. The Interleukin 6 receptor (IL-6R) is found as a transmembrane protein on hepatocytes and subsets of leukocytes, but soluble isoforms of the IL-6R (sIL-6R) are generated by alternative splicing or by limited proteolysis of the A Disintegrin And Metalloproteinases (ADAM) gene family members ADAM10 and ADAM17. Importantly, the sIL-6R in complex with its ligand Interleukin 6 (IL-6) has agonistic functions and requires cells expressing the signal transducing ß-receptor gp130 but not the membrane-bound IL-6R. We have called this process IL-6 trans-signaling. Naturally occurring isoforms of soluble gp130 (sgp130), which are generated by alternative splicing, are natural inhibitors of IL-6 trans-signaling, leaving IL-6 classic signaling via the membrane-bound IL-6R unaffected. We used recombinant sgp130Fc protein and recently generated transgenic mice expressing high levels of sgp130Fc to discriminate between classic and trans-signaling in vivo, and demonstrated that IL-6 trans-signaling is critically involved in generation and maintenance of several inflammatory and autoimmune diseases including chronic inflammatory bowel disease, rheumatoid arthritis, peritonitis and asthma, as well as inflammation-induced colon cancer.  相似文献   

20.
Summary One strain each of the fungus,Aspergillus niger, and the yeast,Saccharomycopsis lipolytica, were investigated for their ability to produce citric acid from the sugars present in hemicellulose hydrolysates.S. lipolytica produced citric acid as efficiently from mannose as from glucose, but failed to assimilate xylose, arabinose or galactose.A. niger readily assimilated mannose, xylose and arabinose, and produced citric acid from these sugars although the yields were lower than from glucose. A possible inhibitory effect of arabinose on citric acid production from other sugars was observed usingA. niger.  相似文献   

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