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1.
In this study, we have formulated chitosan-coated sodium alginate microparticles containing meloxicam (MLX) and aimed to investigate
the correlation between in vitro release and in vivo absorbed percentages of meloxicam. The microparticle formulations were prepared by orifice ionic gelation method with two
different sodium alginate concentrations, as 1% and 2% (w/v), in order to provide different release rates. Additionally, an oral solution containing 15 mg of meloxicam was administered
as the reference solution for evaluation of in vitro/in vivo correlation (ivivc). Following in vitro characterization, plasma levels of MLX and pharmacokinetic parameters [elimination half-life (t
1/2), maximum plasma concentration (C
max), time for C
max (t
max)] after oral administration to New Zealand rabbits were determined. Area under plasma concentration–time curve (AUC0–∞) was calculated by using trapezoidal method. A linear regression was investigated between released% (in vitro) and absorbed% (in vivo) with a model-independent deconvolution approach. As a result, increase in sodium alginate content lengthened in vitro release time and in vivo t
max value. In addition, for ivivc, linear regression equations with r
2 values of 0.8563 and 0.9402 were obtained for microparticles containing 1% and 2% (w/v) sodium alginate, respectively. Lower prediction error for 2% sodium alginate formulations (7.419 ± 4.068) compared to 1%
sodium alginate formulations (9.458 ± 5.106) indicated a more precise ivivc for 2% sodium alginate formulation. 相似文献
2.
Garbayo I Vílchez C Vega JM Nava-Saucedo JE Barbotin JN 《Biotechnology letters》2004,26(23):1825-1827
Streptococcus thermophilusand Lactobacillus bulgaricus were co-immobilized in different systems with varying calcium (0.1–1.5M) and alginate (1–2<><>, w/v) concentrations. Highest lactic acid production was 35 g l1 when both bacteria were in high viscosity beads (1<><>, w/v alginate) hardened in 0.1 M CaCl2 .The gel bead composition affected size and distribution of entrapped lactic acid bacteria. 相似文献
3.
This paper describes multiple shoot regeneration from leaf and nodal segments of a medicinally important herb Centella asiatica L. on Murashige and Skoog’s (MS) medium supplemented with a range of growth regulators. The highest number of multiple shoots
was observed on MS augmented with 3.0 mg dm−3 N6-benzylaminopurine (BAP) and 0.05 mg dm−3 α-naphthaleneacetic acid (NAA). Leaf explant showed maximum percentage of cultures regenerating shoots (81.6 %), with the
highest shoot number (8.3 shoots per explant) and the shoot length (2.1 cm) whereas, nodal explant showed less number of shoots
with callus formation at the base cut end. Successive shoot cultures were established by repeatedly sub-culturing the original
explant on a fresh medium. Rooting of in vitro raised shoots was best induced on half strength MS supplemented with 0.5 mg dm−3 indole-3-butyric acid (IBA) with highest percentage of shoot regenerating roots (76.8 %) with 3–4 roots per shoot. Plantlets
were acclimated in Vermi-compost and eventually established in soil. Contents of chlorophyll, total sugars, reducing sugars and proteins were estimated in
leaf tissue from both in vivo and in vitro raised plants. Chlorophyll content was higher in in vivo plants, whereas other three components were higher in in vitro plants. 相似文献
4.
A genetic transformation system has been developed for callus cells of Crataegus
aronia using Agrobacterium
tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with
5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different
types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red
colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli
were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this
is the first time to report an Agrobacterium-mediated transformation system in Crataegus
aronia. 相似文献
5.
Díaz-Barrera A Soto E Altamirano C 《Journal of industrial microbiology & biotechnology》2012,39(4):613-621
Alginates are polysaccharides that are used as thickening agents, stabilizers, and emulsifiers in various industries. These
biopolymers are produced by fermentation with a limited understanding of the processes occurring at the cellular level. The
objective of this study was to evaluate the effects of agitation rate and inlet sucrose concentrations (ISC) on alginate production
and the expression of the genes encoding for alginate-lyases (algL) and the catalytic subunit of the alginate polymerase complex (alg8) in chemostat cultures of Azotobacter vinelandii ATCC 9046. Increased alginate production (2.4 g l−1) and a higher specific alginate production rate (0.1 g g−1 h−1) were obtained at an ISC of 15 g l−1. Carbon recovery of about 100% was obtained at an ISC of 10 g l−1, whereas it was close to 50% at higher ISCs, suggesting that cells growing at lower sucrose feed rates utilize the carbon
source more efficiently. In each of the steady states evaluated, an increase in algL gene expression was not related to a decrease in alginate molecular weight, whereas an increase in the molecular weight of
alginate was linked to higher alg8 gene expression, demonstrating a relationship between the alg8 gene and alginate polymerization in A. vinelandii for the first time. The results obtained provide a possible explanation for changes observed in the molecular weight of alginate
synthesized and this knowledge can be used to build a recombinant strain able to overexpress alg8 in order to produce alginates with higher molecular weights. 相似文献
6.
Wajahatullah Khan Carlos Costa Alfred Souleimanov Balakrishnan Prithiviraj Donald L. Smith 《Plant Growth Regulation》2011,63(3):243-249
Lipo-chitooligosaccharides (LCOs) are bacteria-to-plant signals required for the establishment of rhizobia–legume nitrogen
fixing symbioses. The ability of LCO [Nod Bj V (C18:1, MeFuc)] isolated from B. japonicum (strain 532C), and of oligomers of chitosan (tetramer, pentamer) and chitin (pentamer) to affect the developmental morphology
of roots in Arabidopsis thaliana (L.) Heynh ecotype Columbia (Col-0) was assessed using an interactive scanner-based image analysis system. LCOs have been
shown to play a role in plant organogenesis at nanomolar concentrations. LCO and the chitin pentamer promoted root growth
and development in Arabidopsis at concentrations of 10 nM and 100 μM, respectively. The LCO treated Arabidopsis plants had about 35% longer roots than untreated control plants. Similarly, treatment with 100 μM chitin pentamer (CHIT5)
resulted in 26% longer roots than the untreated plants; however, chitosan oligomer (CH4 or CH5) treated plants did not differ
from the control plants at either concentration (100 or 1 μM). Both LCOs and the chitin pentamer at higher concentrations
increased root surface area, mean root diameter and number of root tips. However, leaf area increase was observed only in
plants treated with LCO at 10 nM. 相似文献
7.
Hai-Nan Su Bin-Bin Xie Xiu-Lan Chen Jin-Xia Wang Xi-Ying Zhang Bai-Cheng Zhou Yu-Zhong Zhang 《Journal of applied phycology》2010,22(1):65-70
Allophycocyanin (APC) is a minor component of phycobiliproteins in cyanobacteria and red algae. This paper describes a simple
and inexpensive extracting method for isolating APC from Spirulina (Arthrospira) platensis with high efficiency. The crude phycobiliprotein extract was pretreated by ammonium sulfate fractionation. Then, by adding
hydroxylapatite into crude phycobiliprotein extract dissolved in 20 mM phosphate buffer (pH 7.0), APC was selectively adsorbed
by hydroxylapatite but C-phycocyanin (C-PC) was not. The hydroxylapatite was collected and APC was extracted from the crude
phycobiliprotein extract. Then, the enriched APC was washed off from the hydroxylapatite using 100 mM phosphate buffer (pH 7.0).
In this simple extracting method it was easy to remove C-PC and isolate APC in large amounts. The absorbance ratio A
650/A
280 of extracted APC reached 2.0. The recovery yield was 70%, representing 4.61 mg · g−1 wet weight. The extracted APC could be further purified by a simple anion-exchange chromatography with a pH gradient from
5.6 to 4.0. The absorbance ratio A
650/A
280 of the purified APC reached 5.0, and the overall recovery yield was 43%, representing 2.83 mg · g−1 wet weight. Its purity was confirmed by native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE. 相似文献
8.
Janhvi Mishra Mahendra Singh L. M. S. Palni S. K. Nandi 《Plant Cell, Tissue and Organ Culture》2011,104(2):181-186
In vitro grown microshoots of Picrrhiza kurrooa were encapsulated in the alginate beads. Regrowth of encapsulated microshoots, using alginate encapsulation, of P. kurrooa reached 89.33% following 3 months of storage. Amongst developing plantlets, 42.66% exhibited formation of multiple shoots
at the onset of regrowth and 21.43% demonstrated simultaneous formation of shoots and roots. Healthy root formation was observed
in plantlets following 2 weeks of their transfer to half-strength Murashige and Skoog medium containing 1 μM α-naphthalene
acetic acid. Plants were transplanted to the greenhouse in three batches with 95% frequency of survival. The genetic fidelity
of P. kurrooa plants growing out after storage in encapsulated form was ascertained by random amplified polymorphic DNA (RAPD) analysis.
Molecular analysis of randomly selected plants from each batch was conducted using 45 random decamer primers. Of 45 primes
tested, 14 produced scorable amplified products. Total 68 bands were observed amongst them 7.35% bands were polymorphic. Cluster
analysis of the RAPD profile revealed an average similarity coefficient of 0.966 thus confirming genetic stability of plants
derived from encapsulated microshoots following 3 months of storage. 相似文献
9.
Two plant growth promoting rhizobacteria––Sinorhizobium meliloti RMP1 and Pseudomonas aeruginosa GRC2 were studied for integrated nutrient management to obtain improved yield of Brassica juncea. Low concentrations of urea and diammonium phosphate (DAP) stimulated the growth of both S. meliloti RMP1 and P. aeruginosa GRC2. 1 M of urea and 0.35 M of DAP was found lethal for RMP1, while 1.3 M and 0.37 M concentrations of urea and DAP proved to
be toxic for GRC2. Lc50 was observed as 0.49 M of urea and 0.15 M of DAP for RMP1, and 0.66 M urea and 0.18 M of DAP for GRC2. Urea and DAP adaptive variants of RMP1 and GRC2 was isolated. Adaptive bacterial variants had better growth rates at sub-lethal (Lc50) concentrations of urea and DAP as compared to non-adaptive variants. They also retained plant growth promoting attributes
similar to non adaptive variants. GRC2 and RMP1 did not affect the growth of each other and were chemotactically active for DAP, urea as well as root exudates of
B. juncea. Both the isolates colonized well in the rhizosphere of B. juncea, as their populations were recorded ≈5 log10 cfu g−1 after 120 days. Interestingly, the colonization ability was found even better when both strains were co-inoculated, as their
population was recorded in the range of ≈6 log10 cfu g−1 after 120 days. In field trials, application of RMP1 and GRC2 resulted in significant increase in biomass and yield of B. juncea as compared to control. However, yield was better with application of half dose and full dose of recommended fertilizers.
Interestingly, the biomass as well as yield improved further when both isolates were applied together along with half dose
of recommended fertilizers. 相似文献
10.
Sazada Siddiqui Mukesh K. Meghvansi Mushtaq A. Wani Farah Jabee 《Acta Physiologiae Plantarum》2009,31(3):531-536
The effect of cadmium (Cd) was studied on root tips of Pisum sativum L. Seeds of P.
sativum were treated with a series of concentrations ranging from 0.125, 0.250, 0.500 and 1.000 mM for 6 h. The effect of Cd was
analyzed by studying the percentage seed germination, radicle length (RL), mitotic index (MI) and chromosomal aberrations
(CAs) in root tip. The results revealed that Cd had significant impeding effect on the root meristem activity of P.
sativum at 0.500 and 1.000 mM as noticed by reduction in seed germination percentage and RL compared to control. Furthermore, it
also reduced MI in dose-related manner compared to control. Additionally, the variation in the percentage of mitotic abnormalities
was observed. The overall percentage of aberrations generally increased with increasing concentrations of Cd. Among these
abnormalities laggards, bridges, stickiness, precocious separation and fragments were most common. The obtained results demonstrated
that the Cd treatment leads to a significant reduction in MI and increase in CAs. Overall results allow us to suggest that
the Cd has clastogenic effect on the crop. 相似文献
11.
The effects of cadmium (Cd) on germination, and antioxidative enzyme activity (AEA) involving superoxide dismutase, catalase,
peroxidase, and ascorbate peroxidase, and on amounts of malondialdehyde and proline present within Achnatherum inebrians, were determined for specimens infected (E+) vs. non-infected (E−) by Neotyphodium gansuense, and cultivated in the presence of various concentrations of CdCl2 (0, 50, 100, 200 and 300 μmol/l). Under high Cd concentrations (100, 200 and 300 μM), E+ (vs. E−) specimens exhibited a higher
germination rate and index, and higher values for shoot length, root length and dry biomass, but there was no significant
difference (P > 0.05) under low Cd concentrations (0 and 50 μM). AEA and the proline content increased, but malondialdehyde content declined
in the E+ (vs. E−) specimens under high Cd concentrations (100, 200 and 300 μM). There was no significant difference (P > 0.05) under low Cd concentrations (0 and 50 μM). Endophyte infection was concluded to be of benefit to the germination
and anti-oxidative mechanisms within A. inebrians under plant exposures to high CdCl2 concentrations. 相似文献
12.
13.
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
14.
An efficient regeneration protocol for rapid multiplication of Melia azedarach, an economically as well as medicinally important timber-yielding tree, was developed. Nearly 90% of the culture exhibited
axillary bud sprouting and multiple shoot formation from nodal segments derived from 20-year-old candidate plus tree on Murashige
and Skoog (MS) medium supplemented with 5 μM 6-benzyladenine (BA). The highest shoot regeneration frequency (92%), maximum
number of multiple shoots (19.7 ± 0.31) as well as shoot length (4.9 ± 0.08 cm) was induced from nodal explants on MS medium
amended with 5.0 μM BA, 0.5 μM indole-3-acetic acid (IAA) and 30 μM adenine sulfate (AdS). Addition of 250 mg l−1 ammonium sulphate, (NH4)2SO4, and 100 mg l−1 K2SO4, prevented defoliation and tip burning without affecting the number of shoots. The explant harvest period also influenced
the bud break and shoot sprouting from nodal segments. Repeated subculturing of nodal explants on fresh MS medium containing
lower concentration of BA (2.5 μM) along with IAA (0.5 μM), AdS (30 μM) and additives was found most suitable growth regulator
regime for achieving 1.2-fold increase in shoot multiplication rate. The percentage of shoot multiplication as well as the
number of shoots per node remained the same during first three subculture passages, afterwards a decline was recorded. About
90% of the in vitro regenerated shoots were successfully rooted ex vitro by giving a pulse treatment of 250 μM indole-3-butyric
acid for 15 min, followed by their transfer to thermocol cups containing soilrite. The raised plantlets were successfully
acclimatized first under culture room conditions, then to green house with 85% survival rate. 相似文献
15.
To overcome the extracellular salt stress, Methanohalophilus portucalensis FDF1T synthesizes the compatible solute betaine through the methylation of glycine, sarcosine, and N,N-dimethylglycine. S-adenosylmethionine (AdoMet) is the methyl donor. The enzyme sarcosine dimethylglycine N-methyltransferase (SDMT) of M. portucalensis, that catalyzes the formation of N,N-dimethylglycine and glycine betaine, has been purified and characterized. SDMT, a monomer of 33 kDa with a pI at 5.03, has
a narrow substrate specificity limited to using only sarcosine and dimethylglycine as substrates for the methyl transferase
reaction. The K
m values for sarcosine and AdoMet were 2.29 and 0.21 mM, respectively, with a V
max of 0.83 μmol/mg-min (k
cat value of 0.44 s−1). The K
m values for dimethylglycine and AdoMet were 3.76 and 0.59 mM, respectively, with a V
max of 4.88 μmol/mg-min (k
cat of 2.68 s−1). A high concentration of the end product betaine (2.0 M) did not affect the SMT activity, but it slightly inhibited the
DMT activity. Both activities were also not affected by potassium or sodium ions in concentrations of 200–1,000 mM. We compared
this novel archaeal SDMT enzyme to other similar bacterial transferases as well as to the glycine sarcosine dimethylglycine
methyltransferase found also in M. portucalensis. 相似文献
16.
Summary Efficient and highly reproducible induction of somatic embryogenesis was obtained in four out of seven selected clones of
neem, Azadirachta indica A. Juss. This was achieved either directly from root and nodal explants or indirectly from callus cultures initiated from
leaf explants excised from 1-yr-old axenic plants. Direct induction of somatic embryogenesis was achieved both from nodal
and root segments within 8 wk of culture on MS1 medium without growth regulators. However, the addition of 2.3–4.5 μM thidiazuron and 0.5 μM 2,4-dichlorophenoxyacetic acid into the medium were necessary to induce somatic embryogenesis via callus phase from leaf
explants. Repetitive embryogenesis was observed within 3–4 wk following transfer of somatic embryos to a plant growth regulator-free
medium. When somatic embryos of nodal and root segments were left on the induction medium without subculturing, approximately
15% of the somatic embryos developed into whole plantlets after passing through a series of developmental stages. Plantlets
thus produced were hardy, lush green, and acclimatized casily under greenhouse conditions. However, somatic embryos derived
from leaf explants showed low conversion rates (<5%). HPLC analysis revealed no detectable levels of azadirachtin in somatic
embryos. 相似文献
17.
Summary Foliar nutrition has been conceived as a possible means of overcoming the recalcitrance of Prosopis chilensis (Molina) Stuntz explants to standard in vitro culture. The foliar uptake of cations (K from 20 gl−1 KNO3 and Ca from 50 gl−1 CaCl2), anions (NO3 from 50 gl−1 KNO3 and PO4 from 50 gl−1 NaH2PO4), and glucose from a 100 mg l−1 solution studied. All of the nutrients examined were absorbed. The efficacy of foliar nutrition in prolonging the vigor of
micropropagated P. chilensis shoot tips was compared with nutrients supplied as a liquid to the base of the stem (liquid) or as an agar-solidified medium
(agar). A foliar-feeding apparatus was constructed that employed pressurization of the medium reservoir to drive the medium
into the culture vessel with a passive return by a siphoning effect. The medium used was Murashige and Skoog with 30 gl−1 sucrose, 0.1 mgl−1 benzylaminopurine, and 1 mgl−1 indole-3-butyric acid. Over a 9-wk test period it was found that explants cultured by foliar nutrition performed significantly
better than those grown on agar for shoot length, nodal production, and leaf retention; and better than liquid MS for node
production. There was no significant difference among the three treatments in percentage survival, percentage rooting, or
the mean number of roots. 相似文献
18.
The gene encoding malate dehydrogenase (MDH) was overexpressed in a pflB ldhA double mutant of Escherichia coli, NZN111, for succinic acid production. With MDH overexpression, NZN111/pTrc99A-mdh restored the ability to metabolize glucose anaerobically and 0.55 g/L of succinic acid was produced from 3 g/L of glucose
in shake flask culture. When supplied with 10 g/L of sodium bicarbonate (NaHCO3), the succinic acid yield of NZN111/pTrc99A-mdh reached 1.14 mol/mol glucose. Supply of NaHCO3 also improved succinic acid production by the control strain, NZN111/pTrc99A. Measurement of key enzymes activities revealed
that phosphoenolpyruvate (PEP) carboxykinase and PEP carboxylase in addition to MDH played important roles. Two-stage culture
of NZN111/pTrc99A-mdh was carried out in a 5-L bioreactor and 12.2 g/L of succinic acid were produced from 15.6 g/L of glucose. Fed-batch culture
was also performed, and the succinic acid concentration reached 31.9 g/L with a yield of 1.19 mol/mol glucose. 相似文献
19.
Giovanni Iapichino Marcello Airò 《In vitro cellular & developmental biology. Plant》2008,44(4):330-337
Multiple shoots were induced on stem segments of an 8-y-old plant of Metrosideros excelsa Sol ex Gaertn. “Parnel”. Axillary shoots produced on uncontaminated explants were excised, segmented, and recultured in the
same medium to increase the stock of shoot cultures. The Murashige and Skoog (MS) medium, augmented with different concentrations
of 2- isopenthenyladenine (2iP) and indole-3-acetic acid (IAA), either singly or in combinations, as potential medium for
shoot multiplication by nodal segments was tested. In the following experiment, equal molar concentrations of four cytokinins
[2iP, kinetin, zeatin, and N
6-benzyladenine (BA)] in combination with equal molar concentrations of three auxins [IAA, α-naphthaleneacetic acid (NAA),
and indole-3-butyric acid (IBA)] were tested for ability to induce axillary shoot development from single-node stem segments.
The highest rate of axillary shoot proliferation was induced on MS agar medium supplemented with 1.96μM 2iP and 1.14μM IAA
after 6 wk in culture. Different auxins (IAA, IBA, and NAA) were tested to determine the optimum conditions for in vitro rooting of microshoots. The best results were accomplished with IAA at 5.71μM (89% rooting) and with IBA at 2.85 or 5.71μM
(86% and 86% rooting, respectively). Seventy and 90 percent of the microshoots were rooted ex vitro in bottom-heated bench (22 ± 2°C) after 2 and 4 wk, respectively. In vitro and ex vitro rooted plantlets were successfully established in soil. 相似文献