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91.
D. Chakrabarty Y. H. Dewir E. J. Hahn S. K. Datta K. Y. Paek 《Plant Growth Regulation》2007,51(1):11-19
The present study investigated the dynamics of nutrient utilization and various growth and physiological parameters during
in vitro proliferation of apple root stock ‘M9 EMLA’ in two different bioreactor systems, i.e. temporary and continuous immersions.
Individual shoots obtained from temporary immersion system had higher dry mass and were of better quality than those obtained
from continuous immersion. In continuous immersion bioreactor, apple shoots appeared to utilize more nutrients from liquid
culture medium than that from temporary immersion. The shoot growth was limited by the availability of phosphate and nitrogen
in continuous immersion system. The shoots produced in temporary immersion bioreactor showed higher photosynthetic rate, maximum
quantum yield of photosystem-II and slow but steady rate of nutrient absorption, indicating the occurrence of higher photomixotrophic
metabolism. The study also showed that high level of antioxidant scavenging enzymes in shoots grown in continuous immersion
system induced physiological changes to foster adaptation to stresses. 相似文献
92.
Most plants are resistant to the majority of pathogens. Susceptibility is the exception to the more common state of resistance,
i.e., being refractory to infection. However, plant pathogens cause serious economic losses by reducing crop yield and quality.
Although such organisms are relatively simple genetic entities, in plants, the mechanisms underlying the generation of disease
symptoms and resistance responses are complex and, often, unknown. The study of genes associated with plant-pathogen resistance
addresses fundamental questions about the molecular, biochemical, cellular, and physiological means of these interactions.
Over the past 10 years, the cloning and analysis of numerous plant resistance genes has led researchers to formulate unifying
theories about resistance and susceptibility, and the co-evolution of plant pathogens and their hosts. In this review, we
discuss the identification of response genes that have been characterized at the molecular level, as well as their putative
links to various signaling pathways. We also summarize the knowledge regarding crosstalk among signaling pathways and plant
resistance genes. 相似文献
93.
Antiobesity effect of trans-10,cis-12-conjugated linoleic acid-producing Lactobacillus plantarum PL62 on diet-induced obese mice 总被引:1,自引:0,他引:1
AIMS: To observe the antiobesity activity of trans-10,cis-12-conjugated linoleic acid (CLA)-producing lactobacillus in mice. METHODS AND RESULTS: Lactobacillus plantarum PL62, which can grow in the presence of linoleic acid, was selected and studied. The culture supernatant of Lact. plantarum PL62 contained trans-10,cis-12-conjugated linoleic acid (6.4 microg ml(-1)), and the crude enzyme prepared from washed cells produced trans-10,cis-12 CLA (1395 microg mg(-1) protein). Lact. plantarum PL62 reduced the weights of epididymal, inguinal, mesenteric, and perirenal white adipose tissues and significantly reduced the blood levels of total glucose and body weights of mice (P<0.01). CONCLUSIONS: trans-10,cis-12-CLA-producing Lact. plantarum PL62 can exert the same antiobesity activity as trans-10,cis-12-CLA in mice. SIGNIFICANCE AND IMPACT OF THE STUDY: trans-10,cis-12-CLA-producing Lactobacillus can be a replacement for CLA for obesity treatment via the continuous production of trans-10,cis-12-CLA. The results provide a novel opportunity to develop foods with antiobesity activity. 相似文献
94.
Soon Lim Yun-Hee Kim Sun-Hyung Kim Suk-Yoon Kwon Haeng-Soon Lee Jin-Seog Kim Kwang-Yun Cho Kee-Yoeup Paek Sang-Soo Kwak 《Molecular breeding : new strategies in plant improvement》2007,19(3):227-239
Oxidative stress is one of the major factors causing injury to plants exposed to environmental stress. Transgenic sweetpotato
[Ipomoea batatas (L.) Lam. cv. Yulmi] plants with an enhanced tolerance to multiple environmental stresses were developed by expressing the
genes of both CuZn superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) under the control of an oxidative stress-inducible
SWPA2 promoter in the chloroplasts of sweetpotato plants (referred to as SSA plants). SSA plants were successfully generated by
the particle bombardment method and confirmed by PCR analysis. When leaf discs of SSA plants were subjected to 5 μM methyl viologen (MV), they showed approximately 45% less damage than non-transformed (NT) plants. When 200 μM MV was sprayed onto the whole plants, SSA plants showed a significant reduction in visible damage compared to leaves of NT
plants, which were almost destroyed. The expression of the introduced CuZnSOD and APX genes in leaves of SSA plants following
MV treatment was significantly induced, thereby reflecting increased levels of SOD and APX in the chloroplasts. APX activity
in chloroplast fractions isolated from SSA plants was approximately 15-fold higher than that in their counterparts from NT
plants. SSA plants treated with a chilling stress consisting of 4°C for 24 h exhibited an attenuated decrease in photosynthetic
activity (Fv/Fm) relative to NT plants; furthermore, after 12 h of recovery following chilling, the Fv/Fm of SSA plants almost
fully recovered to the initial levels, whereas NT plants remained at a lower level of Fv/Fm activity. These results suggest
that SSA plants would be a useful plant crop for commercial cultivation under unfavorable growth conditions. In addition,
the manipulation of the antioxidative mechanism in chloroplasts can be applied to the development of various other transgenic
crops with an increased tolerance to multiple environmental stresses. 相似文献
95.
Kim DS Jung MY Kang A Cho J Sin Y Paek J Kim DW Kim RN Nam SH Kim A Park HS Choi SH Chang YH 《Journal of bacteriology》2012,194(9):2405-2406
A new Peptoniphilus species has been isolated from samples from a patient who was scheduled for endoscopic sinus surgery for chronic rhinosinusitis. The isolate, Peptoniphilus rhinitidis 1-13(T) (KCTC 5985(T)), can use peptone as a sole carbon source and produce butyrate as a metabolic end product. This is the first report of the draft genome sequence of a novel species in the genus Peptoniphilus within the group of Gram-positive anaerobic cocci. 相似文献
96.
Kim DS Paek J Shin JH Kim DW Jung MY Kim RN Sin Y Kook JK Nam SH Kim A Kang A Park HS Choi SH Chang YH 《Journal of bacteriology》2012,194(10):2748-2749
A new Myroides species has been isolated from the urine of a patient with fever in spite of multiple antibiotic treatments who had undergone a radical hysterectomy for cervical cancer and percutaneous nephrostomies for hydronephrosis in the past. The isolate, Myroides injenensis M09-0166(T) (KCTC 23367(T)), showed a high level of resistance to multiple antibiotic agents. Here we provide the first report of the draft genome sequence of a novel species in the genus Myroides within the nonfermenting Gram-negative group. 相似文献
97.
Qiaoping?Qin Quentin?Kaas Chi?Zhang Luping?Zhou Xiaoyan?Luo Mingbing?Zhou Xiaoming?Sun Lanlan?Zhang Kee-Yoeup?Paek Yongyi?CuiEmail author 《Journal of Plant Growth Regulation》2012,31(2):139-155
Massive flowering of tropical Phalaenopsis orchids is coordinated by the cold-induced release of reproductive bud dormancy. Light and temperature are the two key factors
integrated by the dormancy mechanism to both stop and reactivate the meristem development of many other angiosperm species,
including fruit trees and ornamental plants. It is well established that leaves and roots play a major role in inducing flower
development; however, currently, knowledge of molecular events associated with reproductive bud dormancy release in organs
other than the bud is limited. Using differential gene expression, we have shown that the leaves of a hybrid of Phalaenopsis species, Doritaenopsis ‘Tinny Tender’, undergo major metabolic modifications. These changes result in the production of sucrose and amino acids,
both of which can sustain bud outgrowth, and auxin and ethylene, which may play important roles in awaking the dormant buds.
Intake of abscisic acid and synthesis of the hormone jasmonate may also explain the inhibition of vegetative growth that coincides
with bud growth. Interestingly, many genes that were upregulated by cold treatment are homologous for genes involved in flower
induction and vernalization in Arabidopsis, indicating that processes regulating flowering induction and those regulating reproductive bud dormancy release may use
similar pathways and effector molecules. 相似文献
98.
Chitinase is a rate-limiting and endo-splitting enzyme involved in the bio-degradation of chitin, an important component of the cuticular exoskeleton and peritrophic matrix in insects. We isolated a cDNA-encoding chitinase from the last larval integument of the cabbage moth, Mamestra brassicae (Lepidoptera; Noctuidae), cloned the ORF cDNA into E. coli to confirm its functionality, and analyzed the deduced amino acid sequence in comparison with previously described lepidopteran chitinases. M. brassicae chitinase expressed in the transformed E. coli cells with the chitinase-encoding cDNA enhanced cell proliferation to about 1.6 times of the untransformed wild type strain in a colloidal chitin-including medium with only a very limited amount of other nutrients. Compared with the wild type strain, the intracellular levels of chitin degradation derivatives, glucosamine and N-acetylglucosamine were about 7.2 and 2.3 times higher, respectively, while the extracellular chitinase activity was about 2.2 times higher in the transformed strain. The ORF of M. brassicae chitinaseencoding cDNA consisted of 1686 nucleotides (562 amino acid residues) except for the stop codon, and its deduced amino acid composition revealed a calculated molecular weight of 62.7 and theoretical pI of 5.3. The ORF was composed of N-terminal leading signal peptide (AA 1-20), catalytic domain (AA 21-392), linker region (AA 393-498), and C-terminal chitin-binding domain (AA 499-562) showing its characteristic structure as a molting fluid chitinase. In phylogenetic analysis, the enzymes from 6 noctuid species were grouped together, separately from a group of 3 bombycid and 1 tortricid enzymes, corresponding to their taxonomic relationships at both the family and genus levels. 相似文献
99.
Lee HY Park JH Seok SH Baek MW Kim DJ Lee KE Paek KS Lee Y Park JH 《Biochimica et biophysica acta》2006,1761(7):736-744
Many previous studies have reported that conjugated linoleic acid could be produced by starter culture bacteria, but the effects of the bacteria were not investigated. Moreover, there was no evidence of the conjugated linoleic acid-producing bacteria having potential health or nutritional effects related to conjugated linoleic acid, including reducing body fat. Here, we investigated the anti-obesity effect of Lactobacillus rhamnosus PL60, a human originated bacterium that produces t10, c12-conjugated linoleic acid, on diet-induced obese mice. After 8 weeks of feeding, L. rhamnosus PL60 reduced body weight without reducing energy intake, and caused a significant, specific reduction of white adipose tissue (epididymal and perirenal). Although the size of epididymal adipocytes was not reduced by L. rhamnosus PL60, apoptotic signals and UCP-2 mRNA levels increased in adipose tissue. Liver steatosis, a well known side effect of CLA, was not observed by L. rhamnosus PL60 treatment; on the contrary it seemed to be normalized. Results showed that the amount of conjugated linoleic acid produced by Lactobacillus rhamnosus PL60 was enough to produce an anti-obesity effect. 相似文献
100.
Copper-induced changes in the growth, oxidative metabolism, and saponin production in suspension culture roots of Panax ginseng in bioreactors 总被引:3,自引:0,他引:3
Roots of Panax ginseng exposed to various concentrations of Cu (0.0, 5, 10.0, 25.0, and 50.0 μM) accumulated high amounts of Cu in a concentration-dependent and duration-dependent manner. Roots treated with 50 μM Cu resulted in 52% and 89% growth inhibition after 20 and 40 days, respectively. Saponin synthesis was stimulated at a Cu concentration between 5 and 25 μM but decreased at 50 μM Cu. Malondialdehyde content (MDA), lipoxygenase activity (LOX), superoxide ion (O2
•−) accumulation, and H2O2 content at 5 and 10 μM Cu-treated roots were not increased but strongly increased at 50 μM Cu resulting in the oxidation of ascorbate (ASC) and glutathione (GSH) to dehydroascorbate (DHA) and glutathione disulfide (GSSG), respectively indicating a clear oxidative stress. Seven well-resolved bands of superoxide dismutase (SOD) were detected in the gel and an increase in SOD activity seemed to be mainly due to the induction of Fe-SOD 3. Five to 10 μM Cu slightly induced activity of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR), guaiacol peroxidase (G-POD) but inhibited monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR) enzyme activities. No changes in catalase (CAT) activity and in activity gel were found up to 25 μM Cu, but both G-POD and CAT activities were inhibited at 50 μM Cu. Glutathione metabolism enzymes such as γ-glutamylcysteine synthetase (γ-GCS), glutathione-S-transferase (GST), and glutathione peroxidase activities (GPx) were activated at 5 and 10 μM Cu but were strongly inhibited at 50 μM Cu due to the Cu accumulation in root tissues. The strong depletion of GSH at 50 μM Cu was associated to the strong induction of γ-glutamyltranspeptidase (γ-GGT) activity. These results indicate that plant could grow under Cu stress (5–25 μM) by modulating the antioxidant defense mechanism for combating Cu induced oxidative stress. 相似文献