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1.
Bacillus thuringiensis subsp israelensis (Bti) and subsp kurstaki (Btk); (2) vegetative cells derived from these BT products; and (3) Gram-positive and Gram-negative bacteria used as controls.
The XTT-kinetic assay improved sensitivity and early reading of MIC breakpoints. The conventional colony count method for
determining minimal bactericidal concentration (MBC) was used to validate a multi-sample dot-blot assay in which organisms
in individual MIC assays are trapped free of residual antibiotic and their viability is estimated by in situ conversion of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] to insoluble formazan. Tolerance (MBC/MIC)
for most antibiotics was low (≤4). Resistance to β-lactams was attributed to β-lactamase activity in both BT products and
cultures derived from them. MIC and MBC breakpoints in spore-based assays were also approximated by changes in genome copy,
using δ-endotoxin and β-lactamase genes as probes. The DNA assays are effective for monitoring and authenticating organisms
in microbe-containing biotechnology products.
Received 29 September 1998/ Accepted in revised form 12 February 1999 相似文献
2.
A novel actinomycete strain YIM 31724T was isolated from a soil sample collected from Dali, Yunnan Province, People’s Republic of China. The strain is characterized
by white to yellow white aerial mycelia, spiral spore chains and smooth spore surface. The cell wall of strain YIM 31724T contained LL-diaminopimelic acid (A2pm) and traces of meso-A2pm. Whole-cell hydrolysates contained mainly glucose and small amounts of galactose and xylose. The menaquinones were MK-9(H6) (31%) and MK-9(H8) (69%). Phosphatidylethanolamine was the diagnostic phospholipid. The DNA G+C content of strain YIM 31724T was 67.2 mol%. Phylogenetic analysis indicated that the strain belongs to the genus Streptomyces, with highest similarity to Streptomyces rimosus subsp. rimosus JCM 4667T (rRNA gene sequence similarity value of 98.9%) and Streptomyces erumpens DSM 40941T (rRNA gene sequence similarity value of 98.7%). Based on its phenotypic and genotypic characteristics, including low DNA–DNA
hybridization results, strain
is proposed as the type strain of a novel species, Streptomyces daliensis sp. nov. 相似文献
3.
Several studies reported the antioxidant activity of bifidobacteria using assays in vitro. In present study, the in vitro
and in vivo antioxidant activity of Bifidobacterium animalis 01 was investigated. Culture supernatant, intact cells, and intracellular cell-free extracts of B. animalis 01 were involved in this study. The antioxidant assays in vitro included lipid peroxidation assay, 1,1-diphenyl-2-picrylhydrazyl
(DPPH) assay, hydroxyl radical (
•
OH) assay and superoxide anion (
\textO2 - {\text{O}}_{2}^{ - } ) assay. The antioxidant assays in vivo were conducted using mice model. Activities of antioxidative enzymes, malondialdehyde
(MDA) content in serums and livers of aging mice were evaluated. Monoamine oxidase (MAO) activity and lipofuscin level in
brains of aging mice were also characterized. Results showed that culture supernatant, intact cells and intracellular cell-free
extracts of B. animalis 01 could effectively scavenge free radicals, significantly enhance mice’s activities of antioxidative enzymes and reduce
mice’s MDA content, lipofuscin level and MAO activity. Our results indicated that B. animalis 01 has the potential to be developed into a dietary antioxidant supplements. 相似文献
4.
Arleta Malecka Aneta Piechalak Barbara Tomaszewska 《Acta Physiologiae Plantarum》2009,31(5):1053-1063
The lead absorbed by the roots induce oxidative stress conditions through the Reactive oxygen species (ROS) production for
the pea plants cultivated hydroponically for 96 h on a Hoagland medium with the addition of 0.1 and 0.5 mM of Pb(NO3)2. The alterations in
\textO2 - · {\text{O}}_{2}^{ - \cdot } and H2O2 concentrations were monitored spectrophotometrically which show a rapid increase in
\textO2 - · {\text{O}}_{2}^{ - \cdot } production during the initial 2 h, and in case of H2O2, during the eighth hour of cultivation. The level of ROS remained higher at all the time points for the roots of the plants
cultivated with Pb2+ and it was proportional to metal concentration. The production of
\textO2 - · {\text{O}}_{2}^{ - \cdot } and H2O2 was visualized by means of fluorescence microscope technique. They are produced in nonenzymatic membrane lipid peroxidation
and its final product is Malondialdehyde, the level of which increased together with the level of H2O2. As stress intensity raised (duration of treatment and Pb2+ concentration), so did the activities of superoxide dismutases, catalase and ascorbate peroxidase antioxidative enzymes and
of low-molecular antioxidants, particularly glutathione (GSH), homoglutathione (h-GSH) and cysteine substrate toward their
synthesis. The root cells redox state (GSH/GSSG) dropped proportionally to lead stress intensity. 相似文献
5.
Interfacial tension has been determined for phosphatidylcholine (PC)–decanoic acid (DA) and PC–decylamine (DE) membranes.
PC (lecithin), DA and DE were used in the experiments; the interfacial tension values of the pure components are 1.62 × 10−3, −2.38 × 10−2 and −3.88 × 10−2 N/m (hypothetical values for DA and DE), respectively. The 1:1 complexes were formed during formation of PC–DA and PC–DE
membranes. The following parameters describing the complexes were determined: the surface concentrations of the lipid membranes
formed from these complexes, A3 - 1 A_{3}^{ - 1} ; the interfacial tensions of such membranes, γ
3; and the stability constants of these complexes, K. 相似文献
6.
Ming Chang Shun-Gui Zhou Na Lu Jin-Ren Ni 《World journal of microbiology & biotechnology》2008,24(4):441-447
Production of Bacillus thuringiensis (Bt) based bioinsecticide was studied by using starch processing wastewater (SPW) as a raw material. Results indicated that
the nutrients contained in SPW were sufficient for growth, sporulation and δ-endotoxin production of Bacillus
thuringiensis subsp. kurstaki (Btk). The final cell counts and spore counts achieved in SPW medium were 72% and 107% respectively higher than those in
the soybean meal based commercial medium. Higher δ-endotoxin yield of 2.67 mg mL−1 and higher entomotoxicity of 1,050 IU μL−1 were also obtained in SPW medium as compared with the commercial medium at the end of fermentation. The morphological observations
also revealed that the fermentation cycle of Btk could be shortened in this new medium. This process provides solutions for
safe SPW disposal and production of high potency and low cost bioinsecticide. 相似文献
7.
Zamora-Castro J Paniagua-Michel J Lezama-Cervantes C 《Marine biotechnology (New York, N.Y.)》2008,10(2):181-189
A novel alternative for wastewater effluent bioremediation was developed using constructed microbial mats on low-density polyester.
This biotechnology showed high removal efficiencies for nitrogen and phosphorous in a short retention time (48 h): 94% for
orthophosphate (7.78 g m3 d−1), 79% for ammonium (11.30 g m−3 d−1), 78% for nitrite (7.46 g m−3 d−1), and 83% for nitrate (8.55 g m−3 d−1). The microbial mats were dominated by Cyanobacteria genera such as Chroococcus sp., Lyngbya sp., and bacteria of the subclass Proteobacteria representative of the Eubacteria Domain. Nitzschia sp. was the dominant Eukaryote Domain. Various N and P substrates in the wastewater permit the growth of self-forming and
self-sustaining bacterial, microalgal, and cyanobacterial communities on a polyester support. The result is the continuous,
self-sufficient growth of microbial mats. This is an innovative, economical, and environmentally safe alternative for the
treatment of wastewater effluents in coastal marine environments. 相似文献
8.
Mammalian metallothioneins (
\textM7\textIIMTs {\text{M}}_7^{\text{IIMTs}} ) show a clustered arrangement of the metal ions and a nonregular protein structure. The solution structures of Cd3-thiolate cluster containing β-domain of mouse β-MT-1 and rat β-MT-2 show high structural similarities, but widely differing
structure dynamics. Molecular dynamics simulations revealed a substantially increased number of
\textNH - \textSg {\text{NH - }}{{\text{S}}^\gamma } hydrogen bonds in β-MT-2, features likely responsible for the increased stability of the Cd3-thiolate cluster and the enfolding protein domain. Alterations in the
\textNH - \textSg {\text{NH - }}{{\text{S}}^\gamma } hydrogen-bonding network may provide a rationale for the differences in dynamic properties encountered in the β-domains of
MT-1, -2, and -3 isoforms, believed to be essential for their different biological function. 相似文献
9.
The data processing method of the turbidimetric bioassay of nisin was modified to facilitate its industrial application. The
influence of the initial indicator concentration was minimized by a redefined specific dose of the bacteriocin as the quotient
between the titer of the added bacteriocin and the initial population density of the indicator in the suspension. It was found
that d
c = 0.125 μg ml−1 was the critical dose of nisin that can cause a complete inhibition of the indicator, Pediococcus acidilactici UL5, with an initial OD of 0.135. To eliminate the interference of the cell debris, an equation, , exploiting d
c, was formulated to obtain the intrinsic survival proportion. The use of the specific dose of the bacteriocin and the intrinsic
survival proportion as parameters of the dose/response curve greatly enhanced its repeatability and feasibility. A dual-dosage
approach was developed to further simplify the conventional standard dose/response curve method. 相似文献
10.
Zimmermann D Kiesel M Terpitz U Zhou A Reuss R Kraus J Schenk WA Bamberg E Sukhorukov VL 《The Journal of membrane biology》2008,221(2):107-121
Interactions of structurally dissimilar anionic compounds with the plasma membrane of HEK293 cells were analyzed by patch
clamp and electrorotation. The combined approach provides complementary information on the lipophilicity, preferential affinity
of the anions to the inner/outer membrane leaflet, adsorption depth and transmembrane mobility. The anionic species studied
here included the well-known lipophilic anions dipicrylamine (DPA−), tetraphenylborate (TPB−) and [W2(CO)10(S2CH)]−, the putative lipophilic anion
and three new heterocyclic W(CO)5 derivatives. All tested anions partitioned strongly into the cell membrane, as indicated by the capacitance increase in patch-clamped
cells. The capacitance increment exhibited a bell-shaped dependence on membrane voltage. The midpoint potentials of the maximum
capacitance increment were negative, indicating the exclusion of lipophilic anions from the outer membrane leaflet. The adsorption
depth of the large organic anions DPA−, TPB− and increased and that of W(CO)5 derivatives decreased with increasing concentration of mobile charges. In agreement with the patch-clamp data, electrorotation
of cells treated with DPA− and W(CO)5 derivatives revealed a large dispersion of membrane capacitance in the kilohertz to megahertz range due to the translocation
of mobile charges. In contrast, in the presence of TPB− and no mobile charges could be detected by electrorotation, despite their strong membrane adsorption. Our data suggest that the
presence of oxygen atoms in the outer molecular shell is an important factor for the fast translocation ability of lipophilic
anions. 相似文献
11.
12.
Juliana Vitória Messias Bittencourt Alexandre Magno Sebbenn 《Tree Genetics & Genomes》2009,5(4):573-582
Araucaria angustifolia is an endangered tropical/subtropical coniferous of great interest for conservation due its economical, ecological, and social
value. Only 3% of original Araucaria forests remain, which are generally confined to small forest fragments. Forest fragmentation can have serious consequences
on genetic process in tree population, affecting long-term fitness and adaptability. To investigate the effects of forest
fragmentation on genetic diversity and the structure of A. angustifolia populations, the genetic diversity of eight microsatellite loci was compared in four small fragmented populations (<22 ha),
four tree groups (five to 11 trees) occurring in pastures and in three plots in a large continuous population. The clearest
effect of fragmentation was the loss of rare alleles (p ≤ 0.05) in fragmented populations (19.4% to 47.2%) and intermediate frequency (0.05 < p ≤ 0.25) and rare alleles (p ≤ 0.05) in tree groups (19% to 86.1%) in comparison to continuous populations. Fragmented populations have significant higher
fixation index (
[^(F)]\textIS = 0.121 \widehat{F}_{\text{IS}} = 0.121 , P < 0.05) than continuous populations (
[^(F)]\textIS = 0.083 \widehat{F}_{\text{IS}} = 0.083 , P < 0.05). High genetic differentiation was detected among tree groups (
[^(G)]\textST¢ = 0.258 \widehat{G}_{{{\text{ST}}}}^{\prime } = 0.258 , P < 0.01) and low among fragments (
[^(G)]\textST¢ = 0.031 \widehat{G}_{{{\text{ST}}}}^{\prime } = 0.031 , P < 0.05) and continuous populations (
[^(G)]\textST¢ = 0.026 \widehat{G}_{{{\text{ST}}}}^{\prime } = 0.026 , P < 0.05), showing a significant bottleneck effect in tree groups. Evidence that forest fragments have experienced a recent
bottleneck was confirmed in at least two studied fragments. The implications of the results for conservation of the fragmented
A. angustifolia populations are discussed. 相似文献
13.
A model of the active transport of ions in the Cascinodiscus wailesii diatom cell is constructed taking into account the transport of H+, Na+, K+, Ca+2, NO3-\mathrm{NO}_{3}^{-}, Cl−, and NH4+\mathrm{NH}_{4}^{+} ions. This model allows calculating intracellular concentrations of basic ions and the biomembrane resting potential. A hierarchical
algorithm “one ion—one transport system” is used in the model. The dependence of the resting potential on the extracellular
concentration of potassium is plotted in terms of the model. The calculated values are in good agreement with the corresponding
experimental data. 相似文献
14.
Ernesto Trucco 《Bulletin of mathematical biology》1954,16(4):279-316
This paper is based on N. Rashevsky's theory of imitative behavior, the underlying idea being that performance of one reaction
by a given individual produces an increased stimulation (or tendency) toward the same reaction in other individuals. For simplicity,
consideration is limited to cases in which each individual may choose only between two (or two main categories of) reactions,
denoted byA andB in the following. However, upon suggestion from Dr. Rashevsky and certainly in better agreement with actual facts, the strength
of imitative interaction is assumed to vary from individual to individual. More precisely, if Ψi denotes the additional excitation caused by imitation in theith individual,PAi the probability for performance of reactionA, andPBi the probability for performance of reactionB by theith individual, we postulate that
where the constants α
ik
′
and β
ik
′
(coefficients of imitative interaction) measure the amount of imitative influence exerted by thekth individual upon theith,N being the total number of individuals in the population. The term — αi Ψi accounts for the spontaneous decay of excitation, and the quantities α
ik
′
and α
ik
′
are assumed to benon-negative. The expressions forPAi andPBi are obtained from H. D. Landahl's theory of conflicting stimuli; they depend non-linearly on the values Ψi.
It is implicit in this formulation that the theory can only be applied if the frequency of contacts between individuals is
not too small. Some further shortcomings and limitations of the model are outlined, and the discussion includes suggestions
for reinterpretation and improvement of the theory.
If all the quantities α
ik
′
and α
ik
′
have the same value, sayA, we return to the case treated by Rashevsky (and Landau, 1950); these authors, however, replace the sums in the equation
above by integrals, which automatically restricts the validity of their results to very large values ofN. Their work may therefore be characterized by the assumption of uniform interaction in large populations. Our equations,
on the other hand, are applicable even to very small groups, and therein lies one of their main advantages.
In this paper the mathematical properties of the non-linear system of equations above are studied with particular reference
to the existence and stability of steady states [dΨi/dt ≡ 0;, i = 1 , 2, . . . N].
A sufficient condition for the existence of only one stable steady state is derived. It may be formulated roughly by stating
that all the coefficients of interaction should be sufficiently small. It that is not the case, there may exist a greater
number of stationary states. In particular, two of them (called “extremal”) have the following properties: they arestable and such that the average number of individuals in the group performing one or the other reaction is the largest (or smallest)
possible as compared with the other steady states. Hence the situation is qualitatively similar to that found by Rashevsky
and Landau.Quantitatively, however, important differences may arise, depending on the nature of the matrix specifying the interaction.
A stable state may be approached through damped oscillations, but this effect is important only if the damping is sufficiently
small for the oscillations to become practically observable. Little information could be obtained on this point, due to mathematical
difficulties.
As mentioned above, the most interesting applications of this theory will be with respect to small populations or to populations
partitioned into subgroups with varying amounts of imitative interaction within as well as between groups. 相似文献
15.
Fluctuating hydrochemistry, as a result of extreme hydrological regimes, imposes major physiological constraints on the biota
of ephemeral saline lakes. While the inverse relationship between salinity and zooplankton species richness is well-known
across salinity gradients, few studies have documented closely the response of zooplankton to seasonal changes in salinity.
Weekly sampling during two flood seasons at Sua Pan, an intermittent saline lake in central Botswana demonstrated the importance
of spatial and temporal salinity gradients for crustacean community composition, associated with a decline in species richness,
from 11 to three species. Conductivity ranged between 320 and 125,800 μS cm−1 during seasonal flooding; changing from dominance by
and , Ca2+ and Mg2+, at the beginning of the floods, to NaCl dominated waters as the lake dried out and salinities increased. pH estimates generally
ranged between 8.6 and 10, with maximum values recorded during initial flooding. Crustaceans comprised mainly Branchinella spinosa, Moina belli, Lovenula africana and Limnocythere tudoranceai, all of which occurred across a wide range of salinities, while halotolerant freshwater species (Metadiaptomus transvaalensis, Leptestheria striatochonca and the ostracods Plesiocypridopsis aldabrae, Cypridopsis newtoni and a newly identified Potamocypris species) disappeared above conductivities of 1,500 μS cm−1. A unique crustacean composition in southern Africa was attributed to Sua Pans’ rare chemical composition among southern
African saline lakes; flood waters on Sua Pan contained a higher proportion of Na+ and , and less K+, Mg2+ and than over 80% of records from salt pans elsewhere in southern African. The freshwater species of crustaceans in Sua Pan were
similar to those found in other southern Africa lakes, and these similarities decreased in lakes with higher pH and proportions
of Na, and less SO4 and Mg in their chemical composition. The predominant saline tolerant species on Sua Pan, however, showed a greater similarity
to those in saline lakes in southern and East Africa with higher proportions of and, particularly, Mg2+ in their chemical composition.
Handling editor: J. M. Melack 相似文献
16.
Competition for nutrients and water between crops and associated hedgerows reduces overall performance of contour hedgerow
systems and hampers its acceptance by rural communities in tropical mountainous regions. Therefore, it is imperative to better
understand competition leading to a decline in crop response close to hedges. In the highlands of North East Thailand spatial
variability in grain yield of maize (Zea mays L., cv. Suwan 1) was assessed for two contour hedgerow systems based on Brachiaria ruziziensis Germain et Evrard (Ruzi grass) barriers or Leucaena leucocephala (Lam) de Wit hedges without or with fertilizer (60 kg N ha−1 and 14 kg P ha−1). Available was analyzed across the slope. In addition, shoot N concentration and δ13C values in leaves were measured for maize plants in the center of the alley and in the row next to and at the upper side
of barriers or hedges. Despite variable field conditions, δ13C values were significantly (p < 0.05) less depleted close to the barriers or hedges, except for 2 out of 16 plots, suggesting that water deficiency was
not the main driver for spatial variability along the alleys. The negative correlation between 13C isotopic discrimination and available in the soil, with R
2 ranging from 0.5 (p < 0.10) to 0.9 (p < 0.01), assigned a major role to N availability in the reduced crop response towards the barriers. The proposed framework
of 13C isotopic discrimination, together with plant and soil N data, is a new approach and was shown to be suitable to determine
N and water competition between hedgerows and crops grown in alleys under field conditions. 相似文献
17.
Three sugarcane fields in Bundaberg and four fields in each of the Burdekin, Tully and Innisfail (Queensland, Australia) were
sampled for spores of Metarhizium anisopliae (Metchnikoff) (Deuteromycotina: Hyphomycetes). This entomopathogenic fungus is the active ingredient in the biocide “BioCaneTM”, which was developed for the management of the greyback canegrub Dermolepida albohirtum (Waterhosue) (Coleoptera: Scarabaeidae) and other scarabs in cane fields. Fields sampled were of different crop ages and
all had a history of BioCaneTM treatment in Plant Cane in past years. Soil samples were taken in each field from four depths (0–10, 10–20, 20–30 and 30–40 cm
below soil level) with the use of an auger. Spore levels were highest at the depths of 10–20 and 20–30 cm. Spore levels differed
between locations with Innisfail and Tully recording the highest spore counts. Spores were also found in the inter-row space
in plots sampled in Tully. Sampling statistics were determined for M. anisopliae spores at the four soil depths with 0.1 and 0.25 precision levels. Three sampling methods were compared (use of marker beads;
use of 100 mm auger and 150 mm auger). Samples that relied on marker beads resulted in higher spore counts, however, an auger
can still be used since BioCaneTM does not normally contain coloured markers. Results obtained demonstrate the ability of the pathogen to translocate in soil
profile and across rows, most likely due to grub movements and other soil fauna. Sampling for M. anisopliae spores provides good monitoring of their levels in soil. The implications of this on grub management decisions are discussed. 相似文献
18.
Algal communities inhabiting four calamine mine spoils differing in time since cessation of exploitation and loaded with high
concentrations of zinc (20,284–61,599 μg g−1 soil DW), lead (2,620–3,885 μg g−1 DW) and cadmium (104–232 μg g−1 DW) were studied. In dump soils of slightly alkaline pH (7.28–7.52) and low nutrient (, , ) concentrations, chlorophyll a content ranged from 0.41 to 2.27 μg g−1 soil DW. In total, 23 algal species were recorded. Chlorophyta were the dominant taxonomic group (42–55% of all identified
species) followed by Cyanobacteria (28–36%) and Heterokontophyta (13–21%). The highest species richness (18) was observed
in the oldest dump (120 years old) with natural succession, while in younger dumps it was lower (11–15). Total algal abundance
ranged between 5.5 and 19.1 × 102 ind. g−1 soil DW, and values of Margalef’s diversity indices (1.59–2.25) were low. These results may suggest that both high concentrations
of heavy metals and low nutrient content influenced the algal communities in all the dumps studied. The differences in algal
microflora observed between tailing dumps may indicate that habitat quality improved with time and that algae isolated from
Zn/Pb-loaded soils may be Zn/Pb-resistant ecotypes of ubiquitous species. 相似文献
19.
Can biological nitrification inhibition (BNI) genes from perennial Leymus racemosus (Triticeae) combat nitrification in wheat farming? 总被引:1,自引:0,他引:1
G. V. Subbarao Ban Tomohiro Kishii Masahiro Ito Osamu H. Samejima H. Y. Wang S. J. Pearse S. Gopalakrishnan K. Nakahara A. K. M. Zakir Hossain H. Tsujimoto W. L. Berry 《Plant and Soil》2007,299(1-2):55-64
Using a recombinant luminescent Nitrosomonas europaea assay to quantify biological nitrification inhibition (BNI), we found that a wild relative of wheat (Leymus racemosus (Lam.) Tzvelev) had a high BNI capacity and releases about 20 times more BNI compounds (about 30 ATU g−1 root dry weight 24 h−1) than Triticum aestivum L. (cultivated wheat). The root exudate from cultivated wheat has no inhibitory effect on nitrification when applied to soil;
however, the root exudate from L. racemous suppressed formation and kept more than 90% of the soil’s inorganic-N in the -form for 60 days. The high-BNI capacity of L. racemosus is mostly associated with chromosome Lr#n. Two other chromosomes Lr#J, and Lr#I also have an influence on BNI production.
Tolerance of L. racemosus to is controlled by chromosome 7Lr#1-1. Sustained release of BNI compounds occurred only in the presence of in the root environment. Given the level of BNI production expressed in DALr#n and assuming normal plant growth, we estimated
that nearly 87,500,000 ATU of BNI activity ha−1 day−1 could be released in a field of vigorously growing wheat; this amounts to the equivalent of the inhibitory effect from the
application of 52.5 g of the synthetic nitrification inhibitor nitrapyrin (one AT unit of BNI activity is equivalent to 0.6 μg
of nitrapyrin). At this rate of BNI production it would take only 19 days for a BNI-enabled wheat crop to produce the inhibitory
power of a standard commercial application of nitrapyrin, 1 kg ha−1. The synthetic nitrification inhibitor, dicyandiamide, blocked specifically the AMO (ammonia monooxygenase) pathway, while
the BNI from L. racemosus blocked the HAO (hydroxylamine oxidoreductase) pathway in Nitrosomonas. Here we report the first finding of high production of BNI in a wild relative of any cereal and its successful introduction
and expression in cultivated wheat. These results demonstrate the potential for empowering the new generation of wheat cultivars
with high-BNI capacity to control nitrification in wheat-production systems.
Responsible Editor: Hans Lambers. 相似文献
20.
The effects of nitric oxide (NO) on caulogenesis, shoot organogenesis and rhizogenesis from hypocotyl explants of Linum usitatissimum were investigated. Exogenously supplied NO donors, 5 μM sodium nitroprusside (SNP), 2 μM S-nitroso-N-acetylpenicillamine (SNAP) and 2 μM 3-morpholinosydnonimine (SIN-1), significantly promoted shoot differentiation from the
hypocotyl explants of L. usitatissimum excised from its in vitro raised seedlings. Potassium ferrocyanide, a structural analogue of SNP, lacking NO group, did not
promote shoot organogenesis. Likewise, products of NO,
\textNO2 - {\text{NO}}_{2}^{ - } and
\textNO3 - {\text{NO}}_{3}^{ - } supplied as 5 μM NaNO2 and 5 μM NaNO3 did not enhance shoot differentiation. Another source of NO, a mixture of sodium nitrite (SN) provided along with ascorbic
acid (AsA), also caused significant promotion in the average number of shoots per responding explant. SNP also augmented the
rhizogenic response of the microshoots in terms of percentage of responding explants, number of roots per responding explant
and average root length. The NO scavengers, 2-(4-carboxy-phenyl)-4, 4, 5, 5-tetramethylimideazoline-1-oxyl-3-oxide (cPTIO)
or methylene blue (MB), provided along with SNP, SNAP, SIN-1 or SN + AsA, at concentrations equimolar to the optimum concentration
of the donors, reversed the promotory influence, thereby, confirming the role of NO in promotion of in vitro morphogenesis.
However, NO scavengers individually did not affect the observed morphogenic processes. Morphological and histological studies
of hypocotyl segments cultured on BM or BM + SNP for 4, 8 and 12 days demonstrated that SNP enhanced shoot differentiation
by inducing a higher number of shoot primordia, each of which develops into a single shoot. 相似文献