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1.
Analysis of the structural and functional properties of chromosomal DNA fragments of Streptococcus thermophilus ST128 delineated the promoter sequence STP2201 and identified its −35, −10 and Shine-Dalgarno regions. STP2201 was used in cloning vectors derived from small resident plasmids pER8 (2094 bp) and pER371 (2672 bp) of S. thermophilus strains to facilitate expression of a Streptomyces sp. marker gene (cholesterol oxidase) in lactic acid bacteria. Cell extracts of ST128 transformants converted up to 75% of
cholesterol into 4-cholesten-3-one during 8 h of incubation.
Received: 8 February 1997 / Accepted: 20 March 1997 相似文献
2.
A controlled growth chamber experiment was conducted to investigate the short-term water use and photosynthetic responses
of 30-d-old carrot seedlings to the combined effects of CO2 concentration (50–1 050 μmol mol−1) and moisture deficits (−5, −30, −55, and −70 kPa). The photosynthetic response data was fitted to a non-rectangular hyperbola
model. The estimated parameters were compared for effects of moisture deficit and elevated CO2 concentration (EC). The carboxylation efficiency (α) increased in response to mild moisture stress (−30 kPa) under EC when
compared to the unstressed control. However, moderate (−55 kPa) and extreme (−70 kPa) moisture deficits reduced α under EC.
Maximum net photosynthetic rate (P
Nmax) did not differ between mild water deficit and unstressed controls under EC. Moderate and extreme moisture deficits reduced
P
Nmax by nearly 85 % compared to controls. Dark respiration rate (R
D) showed no consistent response to moisture deficit. The CO2 compensation concentration (Γ) was 324 μmol mol−1 for −75 kPa and ranged 63–93 μmol mol−1 for other moisture regimes. Interaction between moisture deficit and EC was noticed for P
N, ratio of intercellular and ambient CO2 concentration (C
i/C
a), stomatal conductance (g
s
), and transpiration rate (E). P
N was maximum and C
i/C
a was minimum at −30 kPa moisture deficit and at C
a of 350 μmol mol−1. The g
s and E showed an inverse relationship at all moisture deficit regimes and EC. Water use efficiency (WUE) increased with moisture
deficit up to −55 kPa and declined thereafter. EC showed a positive influence towards sustaining P
N and increasing WUE only under mild moisture stress, and no beneficial effects of EC were noticed at moderate or extreme moisture
deficits. 相似文献
3.
Irzykowska L Bocianowski J Waśkiewicz A Weber Z Karolewski Z Goliński P Kostecki M Irzykowski W 《Journal of applied genetics》2012,53(2):237-247
Thirty single-spore isolates of a toxigenic fungus, Fusarium oxysporum, were isolated from asparagus spears and identified by species-specific polymerase chain reaction (PCR) and translation elongation
factor 1-α (TEF) sequence analysis. In the examined sets of F. oxysporum isolates, the DNA sequences of mating type genes (MAT) were identified. The distribution of MAT idiomorph may suggest that MAT1-2 is a predominant mating type in the F. oxysporum population. F. oxysporum is mainly recognised as a producer of moniliformin—the highly toxic secondary metabolite. Moniliformin content was determined
by high-performance liquid chromatography (HPLC) analysis in the range 0.05–1,007.47 μg g−1 (mean 115.93 μg g−1) but, also, fumonisin B1 was detected, in the concentration range 0.01–0.91 μg g−1 (mean 0.19 μg g−1). There was no association between mating types and the mycotoxins biosynthesis level. Additionally, a significant intra-species
genetic diversity was revealed and molecular markers associated with toxins biosynthesis were identified. 相似文献
4.
Angelica Del Giudice Domenica R. Massardo Filomena Manna Natalia Koltovaya Hans Hartings Luigi Del Giudice Klaus Wolf 《Current microbiology》1997,34(6):382-384
In previous papers (Del Giudice et al. Curr Genet
8:493–497, 1984; Massardo et al. Curr Genet 17:455–457, 1985) we have shown
that strains of Saccharomyces cerevisiae that are devoid of
mitochondrial DNA (rho
o) are resistant to the alkaloid
lycorine isolated from Amaryllis plants, whereas strains containing
mitochondrial DNA (rho
−
, mit
−
,
or rho
+
) are sensitive to this drug. In addition, we were
able to show that the so-called hypersuppressive petites, whose mitochondrial
genomes consist of short regions of DNA containing an ori sequence,
show intermediate resistance. In this paper, we demonstrate that the degree
of suppressiveness of a rho
− mutant correlates with the
degree of resistance to lycorine.
Received: 20 September 1996 / Accepted: 10 January 1997 相似文献
5.
Mineralization of pentachlorophenol in a contaminated soil by Pseudomonas sp UG30 cells encapsulated in κ-carrageenan 总被引:2,自引:0,他引:2
M B Cassidy H Mullineers H Lee J T Trevors 《Journal of industrial microbiology & biotechnology》1997,18(1):43-48
A fermentation process in Escherichia coli for production of supercoiled plasmid DNA for use as a DNA vaccine was developed using an automated feed-back control nutrient
feeding strategy based on dissolved oxygen (DO) and pH. The process was further automated through a computer-aided data
processing system to regulate the cell growth rate by controlling interactively both the nutrient feed rate and agitation
speed based on DO. The process increased the total yield of the plasmid DNA by approximately 10-fold as compared to a manual
fed-batch culture. The final cell yield from the automated process reached 60 g L−1 of dry cell weight (OD600 = 120) within 24 h. A plasmid DNA yield of 100 mg L−1 (1.7 mg g−1 cell weight) was achieved by using an alkaline cell lysis method. Plasmid yield was confirmed using High Performance Liquid
Chromatography (HPLC) analysis. Because cells had been grown under carbon-limiting conditions in the automated process,
acetic acid production was minimal (below 0.01 g L−1) throughout the fed-batch stage. In contrast, in the manual process, an acid accumulation rate as high as 0.36 g L−1 was observed, presumably due to the high nutrient feed rates used to maintain a maximum growth rate. The manual fed-batch
process produced a low cell density averaging 10–12 g L−1 (OD600 = 25–30) and plasmid yields of 5–8 mg L−1 (approximately 0.7 mg g−1 cells). The improved plasmid DNA yields in the DO- and pH-based feed-back controlled process were assumed to be a result
of a combination of increased cell density, reduced growth rate (μ) from 0.69 h−1 to 0.13 h−1 and the carbon/nitrogen limitation in the fed-batch stage. The DO- and pH-based feed-back control, fed-batch process has
proven itself to be advantageous in regulating cell growth rate to achieve both high cell density and plasmid yield without
having to use pure oxygen. The process was reproducible in triplicate fermentations at both 7-L and 80-L scales.
Received 22 March 1996/ Accepted in revised form 20 September 1996 相似文献
6.
The response of barley (Hordeum vulgare L. cv. Akcent) to various photosynthetic photon flux densities (PPFDs) and elevated [CO2] [700 μmol (CO2) mol−1; EC] was studied by gas exchange, chlorophyll (Chl) a fluorescence, and pigment analysis. In comparison with barley grown under ambient [CO2] [350 μmol (CO2) mol−1; AC] the EC acclimation resulted in a decrease in photosynthetic capacity, reduced stomatal conductance, and decreased total
Chl content. The extent of acclimation depression of photosynthesis, the most pronounced for the plants grown at 730 μmol
m−2 s−1 (PPFD730), may be related to the degree of sink-limitation. The increased non-radiative dissipation of absorbed photon energy for
all EC plants corresponded to the higher de-epoxidation state of xanthophylls only for PPFD730 barley. Further, a pronounced decrease in photosystem 2 (PS2) photochemical efficiency (given as FV/FM) for EC plants grown at 730 and 1 200 μmol m−2 s−1 in comparison with AC barley was related to the reduced epoxidation of antheraxanthin and zeaxanthin back to violaxanthin
in darkness. Thus the EC conditions sensitise the photosynthetic apparatus of high-irradiance acclimated barley plants (particularly
PPFD730) to the photoinactivation of PS2.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
The effect of lead on photosynthesis and respiration in detached leaves and in mesophyll protoplasts of Pisum sativum 总被引:2,自引:0,他引:2
Eugeniusz Parys Elżbieta Romanowska Maria Siedlecka Jerzy W. Poskuta 《Acta Physiologiae Plantarum》1998,20(3):313-322
Photosynthesis and transpiration rate of detached leaves of pea (Pisum sativum L. cv. Iłowiecki) exposed to solution of Pb(NO3)2 at 1 or 5 mmol·dm−3 concentrations were inhibited. The higher concentration of this toxicant decreased photosynthesis and transpiration rates
2 and 3 times respectively, and increased respiration by about 20 %, as measured after 24 hours of treatment. Similarly to
Pb(NO3)2, glyceraldehyde solution, an inhibitor of phosphoribulokinase, at 50 mmol·dm−3 concentration decreased the rates of photosynthesis and transpiration during introduction into pea leaves. The rate of dark
respiration, however, remained unchanged during 2 hours of experiment.
The potential photochemical efficiency of PS II (Fv/Fm) and the activity of Rubisco (EC 4.1.1.39) at 5 mmol·dm−3 of Pb(NO3)2 were lowered by 10 % and 20 % respectively, after 24 hours. Neither changes in the activity of PEPC (EC 4.1.1.31) or protein
and pigment contents were noted in Pb-treated leaves. The photosynthetic activity of protoplasts isolated from leaves treated
for 24 or 48 hours with Pb(NO3)2 at 5 mmol·dm−3 concentration was decreased 10 % or 25 %, whereas, the rate of dark respiration was stimulated by about 40 % and 75 %, respectively.
The content of abscisic acid, a hormone responsible for stomatal closure, in detached pea leaves treated for 24 h with 5 mmol·dm−3 of Pb(NO3)2 solution was increased by about 3 times; a longer (48h) treatment led to further increase (by about 7 times) in the amount
of this hormone. The results of our experiments provide evidences that CO2 fixation in detached pea leaves, at least up to 24 hours of Pb(NO3)2 treatment, was restricted mainly by stomatal closure. 相似文献
8.
Charles Masembe Vincent B. Muwanika Silvester Nyakaana Peter Arctander Hans R. Siegismund 《Conservation Genetics》2006,7(4):551-562
Phylogeographic and population genetic studies using sequence information are frequently used to infer species boundaries and history; and to assess hybridization and population level processes. In this study, partial mitochondrial DNA (mtDNA) control region (423 bp) and cytochrome b sequences (666 bp) of Oryx beisa sampled from five isolated localities in its entire current range in Africa were analyzed to investigate the extent of genetic variation and differentiation between populations. We observed high nucleotide diversity at the control region in the total sample (6.3%) but within populations, it varied considerably ranging from 1.6% to 8.1%. Population pairwise genetic differentiation was generally significantly high (ranging from F
ST = 0.15, P<0.01 to F
ST = 0.54, P<0.001). In the total sample, 29 and 12 haplotypes were observed in the control region and the cytochrome b data sets respectively. For both data sets, the haplotypes cluster into three distinct clades (sequence divergence ranged from 6.0%–12.9% to 0.8%–1.0% for the control region and cytochrome b sequences, respectively) that do not correspond to sampling locations. Two of these clades are found in the same localities (Samburu and Marsabit), which represent the O.beisa beisa subspecies, whereas the last clade represents the fringe-eared oryx (O. beisa callotis). We interpret these findings in terms of an ancient hybridization and introgression between two formerly isolated taxa of Oryx beisa. 相似文献
9.
J. E. Tomilova V. V. Kuznetsov M. A. Abdurashitov N. A. Netesova S. Kh. Degtyarev 《Molecular Biology》2010,44(4):606-615
The M1.Bst19I DNA-methyltransferase gene from restriction-modification system Bst19I (recognition sequence 5′-GCATC-3′) in
Bacillus stearothermophilus 19 has been cloned in the expressing vector pJW that carries a tandem of thermo inducible promoters P
R
/P
L
from phage λ. Highly purified enzyme has been isolated by chromatography on various resins from Escherichia coli cells where it is accumulated in a soluble form. The study of M1.Bst19I properties has revealed that the enzyme has a temperature
optimum at 50°C and demonstrates maximal activity at pH 8.0. M1.Bst19I modifies adenine in sequence 5′-GCATC-3′. Kinetic parameters
of M1.Bst19I DNA methylation reaction have been determined as follows: Km for λ DNA is 0.68 ± 0.07 μM, Km for S-adenosyl-L-methionine is 2.02 ± 0.31 μM. Catalytical constant (k
cat) is 1.8 ± 0.05 min−1. Comparative analysis of Target Recognition Domain amino acid sequences for M1.Bst19I and other α-N6-DNA-methyltransferases
has allowed us to suggest the presence of two types of the enzymes containing ATG or ATC triplets in the recognition sequence. 相似文献
10.
Two degenerate primers established from the alignment of highly conserved amino acid sequences of bacterial dihydropyrimidinases
(DHPs) were used to amplify a 330-bp gene fragment from the genomic DNA of Bacillus sp. TS-23 and the amplified DNA was successfully used as a probe to clone a dhp gene from the strain. The open reading frame of the gene consisted of 1422 bp and was deduced to contain 472 amino acids
with a molecular mass of 52 kDa. The deduced amino acid sequence exhibited greater than 45% identity with that of prokaryotic
d-hydantoinases and eukaryotic DHPs. Phylogenetic analysis showed that Bacillus sp. TS-23 DHP is grouped together with Bacillus stearothermophilus d-hydantoinase and related to dihydroorotases and allantoinases from various organisms. His6-tagged DHP was over-expressed in Escherichia coli and purified by immobilized metal affinity chromatography to a specific activity of 3.46 U mg−1 protein. The optimal pH and temperature for the purified enzyme were 8.0 and 60 °C, respectively. The half-life of His6-tagged DHP was 25 days at 50 °C. The enzyme activity was stimulated by Co2+ and Mn2+ ions. His6-tagged DHP was most active toward dihydrouracil followed by hydantoin derivatives. The catalytic efficiencies (kcat/Km) of the enzyme for dihydrouracil and hydantoin were 2.58 and 0.61 s−1 mM−1, respectively. 相似文献
11.
Likhareva Viktoria V. Mikhailova Anna G. Vaskovsky Boris V. Garanin Sergey K. Rumsh Lev D. 《International journal of peptide research and therapeutics》2002,9(2-3):71-76
Summary Enteropeptidase (enterokinase EC 3.4.21.9), catalyzing trypsinogen activation, exhibits unique properties for high efficiency
hydrolysis of the polypeptide chain after the N-terminal tetraaspartyl-lysyl sequence. This makes it a convenient tool for
the processing of fusion proteins containing this sequence. We found the enteropeptidase-catalysing degradation of some bioactive
peptides: cattle hemoglobin beta-chain fragments Hb (2–8) (LTAEEKA) and Hb (1–9) (MLTAEEKAA), human angiotensin II (DRVYIHPF)
(AT). Model peptides with truncated linker WDDRG and WDDKG also were shown to be susceptible to enteropeptidase action. Kinetic
parameters of enteropeptidase hydrolysis for these substrates were determined.K
m values for all substrates with truncated linker (≈10−3 M) are an order of magnitude higher than corresponding values for typical enteropeptidase artificial peptide or fusion protein
substrates with full enteropeptidase linker-DDDDK-(K
m
≈10−4 M).k
cat values for AT, Hb (2–8), WDDRG and WDDKG are ≈30–40 min−1. But one additional amino acid residue at both N-and C-terminus of Hb (2–8) results in a drastic increase of hydrolysis efficiency:k
cat value for Hb (1–9) is 1510 min−1. Recent study demonstrates the possibility of undesirable cleavage of target peptides or proteins containing the above-mentioned
truncated linker sequences; further, the ability of enteropeptidase to hydrolyse specifically several biologically active
peptidesin vitro along with its unique natural substrate trypsinogen was demonstrated. 相似文献
12.
A. M. Fauzi David J. Hardman Alan T. Bull 《Applied microbiology and biotechnology》1996,46(5-6):660-666
The degradation of low concentrations of 1,3-dichloro-2-propanol (1,3-DCP) and related halohydrins by whole cells and cell-free
extracts of soil bacteria has been investigated. Three bacteria (strains A1, A2, A4), isolated from the same soil sample,
were distinguished on the basis of cell morphology, growth kinetics and haloalcohol dehalogenase profiles. Strain A1, probably
an Agrobacterium sp., dehalogenated 1,3-DCP with the highest specific activity (0.33 U mg protein−1) and also had the highest affinity for 1,3-DCP (K
m, 0.1 mM). Non-growing cells of this bacterium dehalogenated low concentrations of 1,3-DCP with a first-order rate constant
(k
1) of 1.13 h−1 . The presence of a non-dehalogenating bacterium, strain G1 (tentatively identified as Pseudomonas mesophilius), did not enhance the dehalogenation rate of low 1,3-DCP concentrations. However, the mixed-species consortium of strains
A1 and G1 had greater stability than the mono-species culture at DCP concentrations above 1.0 gl−1.
Received: 30 April 1996 / Received revision: 30 July 1996 / Accepted: 5 August 1996 相似文献
13.
In three tropical rain forest light environments in Sabah, Malaysia, we compared photosynthesis in seedlings of ten climax
tree species with putatively differing shade tolerances. The objectives of the study were (a) to characterise the range of
photosynthetic responses in ten species of the Dipterocarpaceae and (b) to elucidate those photosynthetic characteristics
that might provide a basis for niche partitioning. Seedlings were acclimated (c. 7 months) in three light environments; understorey, partial shade and a gap (140 m2). The light environments represented a gradation in median diurnal (0630–1830 hours) photon flux density (PFD) ranging from
understorey (4.7 μmol m−2 s−1), through partial shade (21.2 μmol m−2 s−1) to gap (113.7 μmol m−2 s−1). Integrated diurnal PFD were in the sequence gap > partial shade > understorey (15.2, 4.7, 1.3 mol m−2 day−1, respectively). In gap-acclimated plants, species differed in the photosynthetic light-response variables apparent quantum
yield, dark respiration rate, light compensation point, net saturated leaf assimilation rate (A
sat), and in stomatal conductance (g
s sat) when assimilation rate (A) was saturated. A light-demanding pioneer species (Macaranga hypoleuca) and a shade-demanding understorey species (Begonia sp.) had, respectively, higher and lower A
sat and g
s sat than the dipterocarp species. In high-light conditions A
sat and g
s sat were strongly positively correlated in dipterocarp species. Differing photosynthetic characteristics of gap-acclimated plants
suggest that, in these dipterocarp species, different rates of carbon fixation may be an important factor contributing towards
niche partitioning. Mean integrated diurnal A (A
diurnal) in the gap, partial shade and understory were, respectively, 122.9, 52.7, 20.5 mmol m−2 day−1. Differences occurred in A
diurnal of dipterocarp species between light environments. When Macaranga was included, differences in A
diurnal were evident in the gap and partial shade, and in both cases were attributed to the pioneer. For the variable A
diurnal, there was of a shift in the rank position of Macaranga among light environments, but a shift did not occur among the dipterocarp species. Results from this study are consistent
with the idea that rates of carbon fixation per unit leaf area may contribute towards niche differentiation between the climax
and single pioneer species, but not within the group of climax species. Other physiological and/or carbon allocation factors
may be involved in any niche partitioning; dipterocarp species often have inherently different growth rates and susceptibility
to herbivory. As an alternative to niche partitioning, dipterocarp species may co-exist in natural light environments as a
result of habitat disequilibrium or purely stochastic processes.
Received: 2 April 1997 / Accepted: 13 July 1997 相似文献
14.
Laura Pinilla Rodrigo Torres Claudia Ortiz 《World journal of microbiology & biotechnology》2011,27(11):2521-2528
Two wild strains of Zymomonas mobilis were isolated (named as ML1 and ML2) from sugar cane molasses obtained from different farms of Santander, Colombia. Initially,
selection of the best ethanol-producer strains was carried out using ethanol production parameters obtained with a commercial
strain Z. mobilis DSM 3580. Three isolated strains were cultivated in a culture medium containing yeast extract, peptone, glucose and salts,
at pH 6 and 32°C with stirring rate of 65 rpm during 62 h. The best results of ethanol production were obtained with the native
strain ML1, reaching a maximum ethanol concentration of 79.78 g l−1. ML1 and ML2 strains were identified as Z.
mobilis, according to the morphology, biochemical tests and molecular characterization by PCR of specific DNA sequences from Z. mobilis. Subsequently, the effect of different nitrogen sources on production of ethanol was evaluated. The best results were obtained
using urea at a 0.73 g/l. In this case, maximum concentration of ethanol was 83.81 g l−1, with kinetic parameters of yield of ethanol on biomass (YP/X) = 69.01(g g−1), maximum volumetric productivity of ethanol (Qpmax) = 2.28 (g l−1 h−1), specific productivity of ethanol (qP) = 3.54 (h−1) and specific growth rate (μ) = 0.12 h−1. Finally, we studied the effect of different culture conditions (pH, temperature, stirring, C/N ratio) with a Placket-Burman′s
experimental design. This optimization indicated that the most significant variables were temperature and stirring. In the
best culture conditions a significant increase in all variables of response was achieved, reaching a maximum ethanol concentration
of 93.55 g l−1. 相似文献
15.
Isochorismate hydroxymutase (i.e. isochorismate synthase, EC 5.4.99.6) was purified from an anthraquinone-producing cell-suspension
culture of Galium mollugo L. Although attempts to stabilize the labile enzyme met with little success, a substantial increase in enzyme activity was
observed in the presence of glycine betaine (500 mM). Column chromatography on solid supports other than diethylaminoethyl
(DEAE)-Sephacel, Phenylsepharose Cl-4B or Cibacron Blue 3G-A did not give active enzyme preparations. In spite of these drawbacks
the enzyme was purified 573-fold. Enzyme activity depended strictly on the presence of Mg2+. Kinetic data for chorismate in the forward reaction (K
m = 807 μM, V
max = 6.2 pkat · mg−1) and for isochorismate in the reverse reaction (K
m = 675 μM, V
max = 5.9 pkat · mg−1) were determined.
Received: 18 November 1996 / Accepted: 28 December 1996 相似文献
16.
Alasdair J. E. Gordon Jennifer A. Halliday Michael J. Horsfall Barry W. Glickman 《Molecular & general genetics : MGG》1991,227(1):160-164
Summary A novel forward mutational system, based on the acquisition of an Iq-d dominant phenotype from an initial Iq− recessive state, was used to identify second-site frameshift mutation [±1(±3
n
) events] within the N-terminal region of thelacI gene ofEscherichia coli. The DNA sequences are described of forty-six spontaneous and twenty 9-aminoacridine(9-AA)-induced second site mutations.
Although −1 frameshift events dominate both spectra, the nature and site specificity of these events clearly distinguish two
mutational distributions. The spontaneous distribution contains two −(A: T) frameshift hotspots; one within a monotonic A5 run (9 occurrences), the other at a 5′-CACAACAAC-3′ sequence (12 occurrences). In contrast 17 of the 20 mutations recovered after 9-AA treatment involve the loss of a
G: C pair, 14 of which occur at a single site (5′-CGGGC-3′). The striking specificity of the observed mutational hotspots is of interest since this open genetic target contains
similar sequences which were infrequently recovered. 相似文献
17.
M. Piontek 《Mycotoxin Research》2007,23(1):34-38
In biomasses from 22 moulds isolated in housing buildings a Chromatographie HPLC UV/VIS analysis was carried out to assess
the production of sterigmatocystin by fungal isolates. The results are discussed with respect to mycotoxic risk for people
exposed to the presence ofAspergillus versicolor. This fungus is often present on building materials, but does not always produce the carcinogenic mycotoxin sterigmatocystin
(ST). In this study, 19 (86%) of the 22 strains synthesized ST at detectable levels (>0.03 mg kg−1 biomass). Three of the strains (14%) were found to synthesize ST at levels exceeding 100 mg kg−1 of the air-dry mould biomass with laboratory medium. One strain proved to be highly productive and synthesized more than
500 mg kg−1 ST. Thus, it presented the highest mycotoxic danger for the dwellers of the buildings whereA. versicolor infested the walls. However, most strains are low producers of ST, with 12 of 22 isolates synthesizing less than 10 mg kg−1 biomass. Mycotoxigenic and highly productive strains that produced significant amounts of ST (>500 mg kg−1 biomass) were less frequently found, with approximately 5% of all isolates from buildings studied for ST production.
Presented at the 28th Mykotoxin-Workshop, Bydgoszcz, Poland, May 29–31, 2006 相似文献
18.
19.
Maizirwan Mel Abdul Rafiz Abdul Rahman Mohamad Ramlan Mohamed Salleh Yumi Zuhanis Has-Yun Hashim 《World journal of microbiology & biotechnology》2008,24(9):1923-1927
The study was done to improve the viability of the RC1 hybridoma cell in order to produce more amount of monoclonal antibody
(mAb). By using the optimized media, the cell had been cultured in two bioreactor systems which were the MiniPerm and Stirred
Tank bioreactor (ST bioreactor), and the results were compared to the one obtained by using the T-Flask bioreactor which was
used as a standard. The results showed that the ST bioreactor was able to improve the viability of the cell to the value of
91.8% which was a little bit better than the one obtained by the MiniPerm bioreactor (88.6%) and far better than that of achieved
by the T-Flask bioreactor (76.4%). This was well correlated with the good growth performance of the cell in the ST bioreactor
with the specific growth rate (μ) value of 0.0289 h−1 followed by MiniPerm bioreactor with the value of 0.0243 h−1 and then the T-Flask with the value of 0.0151 h−1. The low value of doubling time (t
d
) obtained in the ST bioreactor (24 h) compared to the one obtained in the MiniPerm (29 h) and T-Flask bioreactor (46 h) had
also contributed to the higher value of cell viability. As a result a higher concentration of mAb was able to be produced
by the ST bioreactor (0.42 g l−1) compared to that of the MiniPerm (0.37 g l−1) and T-Flask bioreactor (0.23 g l−1). 相似文献
20.
A Pessoa Jr I M de Mancilha S Sato 《Journal of industrial microbiology & biotechnology》1997,18(6):360-363
Sugar cane bagasse hemicellulosic fraction submitted to hydrolytic treatment with 100 mg of sulfuric acid per gram of dry
mass, at 140°C for 20 min, was employed as a substrate for microbial protein production. Among the 22 species of microorganisms
evaluated, Candida tropicalis IZ 1824 showed TRS consumption rate of 89.8%, net cell mass of 11.8 g L−1 and yield coefficient (Yx/s) of 0.50 g g−1. The hydrolyzate supplemented with rice bran (20.0 g L−1), P2O5 (2.0 g L−1) and urea (2.0 g L−1) provided a TRS consumption rate of 86.3% and a cell mass of 8.4 g L−1. At pH 4.0 cellular metabolism was inhibited, whereas at pH 6.0 the highest yield was obtained. The presence of furfural
(2.0 g L−1) hydroxymethylfurfural (0.08 g L−1) and acetic acid (3.7 g L−1) in the hydrolyzate did not interfere with cultivation at pH 6.0.
Received 25 October 1996/ Accepted in revised form 10 March 1997 相似文献