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91.
92.
Seed of Stlosanthes humilis both have hard integuments and display physiological dormancy, the latter being lost during post-harvest ageing. Ethrel and l-aminocyclopropane-1-carboxylic acid (ACC) partially released scarified young seed from physiological dormancy. Cobalt and silver ions and abscisic acid inhibited germination of scarified non-dormant seed. Abscisic acid also inhibited germination of voung seed promoted by ACC. Thiourea and ethrel plus benzyladenine showed the greatest efficacy in breaking seed dormancy. 相似文献
93.
E. A. Santos R. Keller 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(5):374-379
The effects of glutamate, aspartate, glycine, proline, alanine, taurine, glycerol, glucose and lactate injections on the haemolymph levels of the crustancean hyperglycemic hormone and/or glucose and lactate in the shore crab, Carcinus maenas, were investigated. Only glucose and lactate caused significant changes of hyperglycaemic hormone levels. Glucose injections resulted in a drop of both hormone and lactate, while lactate had an opposite effect, i.e. it raised both crustacean hormone and glucose levels. The results suggest that during increases in glycolytic flux, lactate may cause a release of hormone by a positive feedback mechanism. The hormone would then stimulate glycogenolysis, thus increasing glucose availability. If more glucose is released than is metabolized, excess glucose may leak from the cells and suppress crustancean hyperglycemic hormone release from the X-organ/sinus gland complex by negative feedback.Abbreviations ABTS
2,2-azino-bis (3-ethylbenzthiazoline sulphonic acid)
- ANOVA
one-way analysis of variance
- BSA
bovine serum albumin
- BW
body weight
- CHH
crustacean hyperglycemic hormone
- ELISA
cnzyme-liked immunosorbent assay
- GIH
gonadinhibiting hormone
- IgG
immunoglobin G
- MIH
moult-inhibiting hormone
- MTGXO
medulla terminalis X-organ
- PB
sodium phosphate buffer
- PBS
phosphate buffered saline
- Pi
inorganic phosphate
- XO-SG
X-organ-sinus gland complex 相似文献
94.
L. M. Freitas dos Santos A. G. Livingston 《Applied microbiology and biotechnology》1993,40(1):151-157
The biological treatment of waste-waters containing 1,2-dichloroethane (DCE) in conventional bioreactors results in air-stripping of DCE. In the present work, a novel bioreactor system intended to overcome this problem has been developed for the treatment of a synthetically concocted DCE-containing waste-water (1000 mg DCE l–1). The operation of a conventional air-lift bioreactor at a waste-water flow rate of 0.24 l h–1 led to 33% of the DCE supplied to the reactor being lost to the exit gas stream. The use of the novel enclosed system, operated with a recycling O2 sparge instead of air, resulted in negligible air-stripping at the same waste-water flow rate. A control system was implemented to add O2 as required to maintain the pressure of the recycle gas stream, and a scrubber removed the CO2 produced. Over 99% of DCE supplied was biodegraded during operation of this system, and virtually all carbon entering the system was evolved as CO2.
Correspondence to: A. G. Livingston
Correspondence to: A. G. Livingston 相似文献
95.
M. Diez M. M. Jiménez J. L. Santos 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,87(1-2):17-21
In order to elucidate the possible effects of rye B chromosomes (Bs) on synapsis and metaphase-I associations of the A set, a comparative study between pachytene and metaphase-I-cells of rye plants carrying different numbers of Bs (0–8) has been carried out. The number of Bs was found to be positively correlated with the frequency of synaptic irregularities of the A set, i.e. multivalents and foldback pairing, and with the frequency of pachytene interlockings. It is proposed that interlockings are the origin of these irregularities because both appeared in close proximity in many nuclei. Examples of A-B pairing are described. The frequency of synaptic abnormalities seems to be unrelated to the mean of A chromosome-bound arms at metaphase I. 相似文献
96.
Pablo Morales Alfredo Corell Jorge Martínez-Laso J. Manuel Martín-Villa Pilar Varela Estela Paz-Artal Luis-M. Allende Antonio Arnaiz-Villena 《Immunogenetics》1993,38(5):323-331
Three new allelic forms of the HLA-G DNA sequence (HLA-G*II, HLA-G*III, and HLA-G*IV) have been identified. With the HLA-G*I sequence (previously designated HLA 6.0) as a reference, HLA-G*II shows a silent (G A) mutation at the third base of codon 57, HLA-G*III bears a non-synonymous (A T), but conservative, (Thr Ser) substitution at the first base of codon 31, and HLA-G*IV shows two silent substitutions: (A T) at the third base of codon 107 and (G A) at the third base of codon 57. A rapid method of singling out each allele on genomic DNA has been developed by using polymerase chain reaction amplification followed by restriction endonuclease treatment. Also, more or less strong linkage disequilibria has been found between most HLA-A alleles and either HLA-G*I or *II, both being the most prevalent alleles in the population, with a genotypic frequency of 0.55 and 0.38, respectively; HLA-G*III is very rare and HLA-G*IV has a genotypic frequency of 0.07. An evolutive classification of HLA-A alleles results according to their association with either HLA-G*I or HLA-G*II, which does not correlate with the classical serological cross-reacting groups classification. The finding of a strong and selective A/G linkage disequilibria with most HLA-A alleles, together with the existence of less frequent random A/G associations, may suggest that there exist in different haplotypes true and varied A/G genetic distances (and not a recombinational hotspot). It may be inferred from preliminary data that in primates HLA-A/G haplotypes bearing G*II may have appeared later than those bearing G*I.The nucleotide sequence data reported in this paper have been submitted to the GenBank and EMBL nucleotide sequence databases and have been assigned the following accession numbers: EMBL-X60983 (HLA-G*II), GenBank-M99048 (HLA-G*III), and GenBank-L07784 (HLA-G*IV).The contribution to this paper by P. Morales and A. Corell is equal, and the order of authorship is arbitrary.
Correspondence to: A. Arnaiz-Villena. 相似文献
97.
The effects of four exogenous amino acids (proline, glycine, asparagine and serine) on the production of maize embryogenic callus and on its endogenous amino acid content have been investigated. For this purpose, an established embryogenic line of Type 1 callus from the inbred W64Ao2 has been used. From the results it may be concluded that a concentration of proline exceeding 6 mM is negative for the production of embryogenic callus. When proline is eliminated from the medium, other amino acids tested in certain concentrations yield a percentage of embryogenic callus production that exceeds or equals that of proline. The endogenous free proline content in embryogenic callus is significantly higher than that in non-embryogenic callus regardless of proline presence in the medium. The only exception are the glycine-containing media, in which endogenous free alanine of embryogenic callus increases at the expense of endogenous free proline. This study suggest a positive role of endogenous free proline or alanine accumulation in the embryogenic callus production which might be related to an adaptation to the metabolic changes produced by in vitro culture and embryogenesis induction. Furthermore, these results indicate that treatments with amino acids that are different from proline can be used to improve the efficiency of embryogenic callus production from well established maize callus cultures.Abbreviations Ala
alanine
- Asn
asparagine
- 2,4-d
2,4-dichlorophenoxyacetic acid
- EC
embryogenic callus
- nEC
non-embryogenic callus
- Gaba
gamma-aminobutyric acid
- Glu
glutamic acid
- Gly
glycine
- Pro
proline
- Ser
serine 相似文献
98.
99.
This study is the first report of an algal disease, developed in close association with an endophytic organism, documented for the southeastern Pacific. We describe a disease affecting wild populations of the red alga Iridaea laminarioides Bory in central Chile, characterized by gall development on the surface of sporophytic, cystocarpic, and immature thalli. These abnormal growths result in severe morphological alterations of the affected thalli. Diseased fronds display an aggregated spatial distribution and occur throughout the year, with a maximum in summer followed by a decline in winter. The presence of galls was not associated with broken or torn fronds. Although causality has not been unequivocally demonstrated, our field and laboratory observations indicate a strong association of the galls with infections by an endophytic cyanobacterium, probably belonging to the genus Pleurocapsa. 相似文献
100.
Comparison of glucose fermentation by suspended and gel-entrapped yeast cells: An in vivo nuclear magnetic resonance study 总被引:1,自引:0,他引:1
Phosphorus-31 nuclear magnetic resonance ((31)P NMR) was used to compare the anaerobic metabolism of glucose by suspended and gel-entrapped Saccharomyces bayanus cells. The fermentation of glucose was carried out in a reaction system with continuous circulation through the NMR sample tube. The intracellular pH and the levels of some phosphorylated compounds were the levels of some phosphorylated compounds were noninvasively monitored by (31)P NMR while glucose, fermentation products, and biomass were determined by analytic techniques comparisons showed that no significant differences are observed in the relative concentrations in the spectra, but distinct profiles for the variation of both intracellular and extracellular pH are found. The internal pH of immobilized cells is maintained at a constant value throughout the fermentation as opposed to freely suspended cells for which a steady decrease in the internal pH occurs. A faster and stronger acidification is also observed in the external medium of the assays with suspended cells. Furthermore, higher yields for ethanol and biomass production and lower yields of fermentation by-products are obtained with immobilized cells. It is concluded that the higher intracellular pH achieved in the presence of the gel matrix had a regulatory effect on the metabolism which favored the ethanol production pathway. (c) 1993 John Wiley & Sons, Inc. 相似文献