1.Partitioning and purification of extracellular beta-1,3-1,4-glucanase in aqueous two-phase systems.
Guo-qing HE ; Xiu-yan ZHANG ; Xing-jun TANG ; Qi-he CHEN ; Hui RUAN
Journal of Zhejiang University. Science. B 2005;6(8):825-831
The partition behaviors of beta-1,3-1,4-glucanase, alpha-amylase and neutral proteases from clarified and whole fermentation broths of Bacillus subtilis ZJF-1A5 were investigated. An aqueous two-phase system (polyethylene glycol (PEG)/MgSO(4)) was examined with regard to the effects of PEG molecular weight (MW) and concentration, MgSO(4) concentration, pH and NaCl concentration on enzyme partition and extraction. The MW and concentration of PEG were found to have significant effects on enzyme partition and extraction with low MW PEG showing the greatest benefit in the partition and extraction of beta-glucanase with the PEG/MgSO(4) system. MgSO(4) concentration influenced the partition and extraction of beta-glucanase significantly. pH had little effect on beta-glucanase or proteases partition but affected alpha-amylase partition when pH was over 7.0. The addition of NaCl had little effect on the partition behavior of beta-glucanase but had very significant effects on the partitioning of alpha-amylase and on the neutral proteases. The partition behaviors of beta-glucanase, alpha-amylase and proteases in whole broth were also investigated and results were similar to those obtained with clarified fermentation broth. A two-step process for purifying beta-glucanase was developed, which achieved beta-glucanase recovery of 65.3% and specific activity of 14027 U/mg, 6.6 times improvement over the whole broth.
Bacillus subtilis
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enzymology
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Chemical Fractionation
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methods
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Endo-1,3(4)-beta-Glucanase
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biosynthesis
;
chemistry
;
isolation & purification
;
Extracellular Fluid
;
chemistry
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Phase Transition
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Water
;
chemistry
2.Sequence analysis and expression pattern of MGTA1 gene in rice blast pathogen Magnaporthe grisea.
Jiao-yu WANG ; Xiao-hong LIU ; Jian-ping LU ; Fu-cheng LIN
Journal of Zhejiang University. Science. B 2005;6(8):817-824
MGTA1, a putative fungal Zn(II)(2)Cys(6) transcriptional activator-encoding gene, was isolated from rice blast pathogen Magnaporthe grisea, which is homologous to CLTA1 from Colletotrichum lindemuthianum with 51% identity at protein level. MGTA1 cassette contains a 2370 bp open reading frame, consisting of 6 exons, coding a 790 amino acid peptide. MGTA1 gene exists as a single copy in genomes of 7 strains of M. grisea, and is expressed in tip hyphae, conidia, and mature appressoria of strain Guy11.
Amino Acid Sequence
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Gene Expression Profiling
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Gene Expression Regulation, Fungal
;
physiology
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Magnaporthe
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genetics
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metabolism
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Molecular Sequence Data
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Oryza
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microbiology
;
Sequence Analysis, Protein
3.Behavioral response of tilapia (Oreochromis niloticus) to acute ammonia stress monitored by computer vision.
Jian-yu XU ; Xiang-wen MIAO ; Ying LIU ; Shao-rong CUI
Journal of Zhejiang University. Science. B 2005;6(8):812-816
The behavioral responses of a tilapia (Oreochromis niloticus) school to low (0.13 mg/L), moderate (0.79 mg/L) and high (2.65 mg/L) levels of unionized ammonia (UIA) concentration were monitored using a computer vision system. The swimming activity and geometrical parameters such as location of the gravity center and distribution of the fish school were calculated continuously. These behavioral parameters of tilapia school responded sensitively to moderate and high UIA concentration. Under high UIA concentration the fish activity showed a significant increase (P<0.05), exhibiting an avoidance reaction to high ammonia condition, and then decreased gradually. Under moderate and high UIA concentration the school's vertical location had significantly large fluctuation (P<0.05) with the school moving up to the water surface then down to the bottom of the aquarium alternately and tending to crowd together. After several hours' exposure to high UIA level, the school finally stayed at the aquarium bottom. These observations indicate that alterations in fish behavior under acute stress can provide important information useful in predicting the stress.
Ammonia
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administration & dosage
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Animals
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Artificial Intelligence
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Behavior, Animal
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drug effects
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physiology
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Dose-Response Relationship, Drug
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Exercise Test
;
methods
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Image Interpretation, Computer-Assisted
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methods
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Social Behavior
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Swimming
;
physiology
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Tilapia
;
physiology
4.Isolation and physiological characteristics of a premature senescence mutant in rice (Oryza sativa L.).
Fu-zhen LI ; Song-heng JIN ; Guo-cheng HU ; Ya-ping FU ; Hua-min SI ; De-an JIANG ; Zong-xiu SUN
Journal of Zhejiang University. Science. B 2005;6(8):803-811
A rice pse(t) (premature senescence, tentatively) mutant line, was isolated from 4,500 independent T-DNA inserted transgenic lines. The symptoms of premature senescence appeared more severely than those of the control plants (Zhonghua 11, japonica) at the last development stage. To characterize the mutant and provide basic information on the candidate genes by mapping to a physical region of 220-kb, experiments were carried out in two phytotrons under controlled temperature of 24 degrees C and 28 degrees C, respectively. The content of chlorophyll, soluble protein and MDA (malondialdehyde), net photosynthesis, the antioxidant enzyme activities of SOD (superoxide dismuase) (EC 1.15.1.1) and POD (peroxidase) (EC 1.11.1.7) and the peptidase activities of leaves were measured from top to bottom according to the leaf positions at the flowering stage. Compared with the control plant, the mutant showed the following characteristics: (1) Higher net photosynthesis rate (P(n)) appeared in the 1st and 2nd leaves, contents of chlorophyll and soluble protein were also higher in the 1st leaf; (2) The activities of SOD, POD and peptidase were higher according to the leaf position from top to bottom; (3) The symptom of premature senescence was accelerated in the mutant at 28 degrees C treatment. The MDA content and the SOD and POD activities between the 24 degrees C and 28 degrees C treatment mutants were not significantly different. Content of chlorophyll and soluble protein of leaves mutant decreased rapidly at 28 degrees C treatment. The results show that pse(t) is sensitive to high temperature. The probable function of PSE(T) is discussed.
Aging
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physiology
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Antioxidants
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metabolism
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Apoptosis
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physiology
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Mutation
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Oryza
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classification
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genetics
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growth & development
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Photosynthesis
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physiology
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Plant Leaves
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classification
;
genetics
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growth & development
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Plant Proteins
;
genetics
;
metabolism
5.Effects of the dietary supplementation with fructooligosaccharides on the excretion of nitrogen and phosphorus in Miichthys miiuy fries.
Tian-xing WU ; Zeng-fu SONG ; Li-sheng CAI ; Xue-yan DING ; Qing-sen YU
Journal of Zhejiang University. Science. B 2005;6(8):798-802
Effects of dietary supplementation with fructooligosaccharides on the excretion of nitrogen and phosphorus in Miichthys miiuy fries were investigated. Nine hundred Miichthys miiuy fries were divided into 3 groups, each with triplicates. The basal diet and the basal diet supplemented with carnitine groups were considered as the negative and positive controls respectively. Results showed that the nitrogen concentration in excreted feces decreased significantly in fries fed the diet supplementation with 1000 x 10(-6) fructooligosaccharides and 200 x 10(-6) carnitine (P<0.05). The ammonic-nitrogen concentration decreased significantly in the carnitine group only (P<0.05), indicating the decreasing tendency caused by the supplementation with fructooligosaccharides. Supplementation with both did not have significant effects on the concentration of phosphorus in feces of Miichthys miiuy fries.
Administration, Oral
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Animals
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Dietary Supplements
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Feces
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Fishes
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metabolism
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Nitrogen
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metabolism
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Oligosaccharides
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administration & dosage
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Phosphorus
;
metabolism
6.Effects of supplementary urea-minerals lick block on the kinetics of fibre digestion, nutrient digestibility and nitrogen utilization of low quality roughages.
Yue-ming WU ; Wei-lian HU ; Jian-xin LIU
Journal of Zhejiang University. Science. B 2005;6(8):793-797
Three yearling lambs with a rumen cannula were used to investigate the effects of supplementation with an urea-minerals lick block (ULB) on the kinetics of ruminal fibre digestion, nutrient digestibility and nitrogen (N) utilization of rice straw (RS), ammonia bicarbonate (AB)treated RS (ABRS) and hay prepared from natural pasture. The digestibility of dry matter and organic matter of RS increased by 13.1% and 12.7% (P<0.05) when the diet was supplemented with ULB, and approached to that of ABRS, indicating that the effect of ULB on digestibility of RS is similar to that of AB treatment. The digestibility of ABRS was slightly improved by the ULB feeding. Nitrogen retention was highest in lambs fed on ABRS alone, followed by hay with ULB, and was lowest in animals fed on RS with ULB. However, both the amount and proportion of N retention to N intake were enhanced by ULB supplementation to lambs fed on hay. The proportion of N retained to N digested decreased due to ULB supplementation to lambs fed on RS or ABRS. Supplementing ULB did not greatly influence the rumen degradation of either dry matter or crude protein in each of the three diets. RS and hay had similar values in the potential extent of digestion (PED) and digestion rate of PED (kd) of fibrous materials, but the discrete lag time for RS was lower than that for hay. The AB treatment significantly increased the PED (P<0.05) and kd (P<0.05) of RS. Neither the PED nor kd for RS and ABRS was influenced by ULB supplementation, but the kd for hay significantly increased due to ULB. The lag time for hay was also shortened by the ULB feeding. The ULB improved the digestion of fibre in the rumen of lambs fed on low quality roughage. It is inferred that while ULB is effective in increasing nutrient digestibility of low quality roughages by improving ruminal fibre digestion. A synchronized supply of N and energy to rumen microbes should be considered to improve the efficiency of N utilization when the basal diet is ammoniated straw.
Administration, Oral
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Animal Feed
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Animals
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Dietary Fiber
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metabolism
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Dietary Supplements
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Digestion
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drug effects
;
physiology
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Feeding Behavior
;
drug effects
;
physiology
;
Minerals
;
administration & dosage
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Nitrogen
;
metabolism
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Sheep
;
physiology
;
Urea
;
administration & dosage
7.Tea saponins affect in vitro fermentation and methanogenesis in faunated and defaunated rumen fluid.
Wei-lian HU ; Yue-ming WU ; Jian-xin LIU ; Yan-qiu GUO ; Jun-an YE
Journal of Zhejiang University. Science. B 2005;6(8):787-792
The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were evaluated in the faunated and defaunated rumen fluid. Compared to the control, TS addition decreased the 24 h gas production in the faunated rumen fluid, but had a minor effect on gas yield in the defaunated rumen fluid. The TS significantly reduced methane production in vitro. In the faunated rumen fluid, 0.2 or 0.4 mg/ml TS decreased the 24 h methane emission by 12.7% or 14.0%, respectively. Rumen fluid pH value was affected neither by TS addition nor by defaunation. The TS addition had only minor effects on volatile fatty acids, but the yield and pattern of volatile fatty acids were greatly affected by defaunation. While the molar proportion of acetate was not affected by defaunation, the propionate was significantly increased and the butyrate significantly decreased. Ammonia-N concentration and microbial protein yield were influenced by TS inclusion and defaunation. Inclusion of 0.4 mg/ml TS increased the microbial protein mass by 18.4% and 13.8% and decreased the ammonia-N concentration by 8.3% and 19.6% in the faunated and defaunated rumen fluid, respectively. Protozoa counts were significantly reduced by TS inclusion. The current study demonstrated the beneficial effect of TS on methane production and rumen fermentation, and indicated that this may be due to the effect of the associated depression on protozoa counts.
Animals
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Camellia sinensis
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metabolism
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Eukaryota
;
drug effects
;
physiology
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Fermentation
;
drug effects
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Gastrointestinal Contents
;
drug effects
;
microbiology
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In Vitro Techniques
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Methane
;
metabolism
;
Plant Extracts
;
pharmacology
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Rumen
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metabolism
;
microbiology
;
Saponins
;
pharmacology
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Seeds
;
metabolism
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Sheep
;
Tea
;
chemistry
8.Active changes of lignification-related enzymes in pepper response to Glomus intraradices and/or Phytophthora capsici.
Hu-zhe ZHENG ; Chun-lan CUI ; Yu-ting ZHANG ; Dan WANG ; Yu JING ; Kil Yong KIM
Journal of Zhejiang University. Science. B 2005;6(8):778-786
The activities of enzymes responsible for lignification in pepper, pre-inoculation with arbuscular mycorrhizal (AM) fungus of Glomus intraradices and/or infection with pathogenic strain of Phytophthora capsici, and the biological control effect of G. intraradices on Phytophthora blight in pepper were investigated. The experiment was carried out with four treatments: (1) plants pre-inoculated with G. intraradices (Gi), (2) plants pre-inoculated with G. intraradices and then infected with P. capsici (Gi+Pc), (3) plants infected with P. capsici (Pc), and (4) plants without any of the two microorganisms (C). Mycorrhizal colonization rate was reduced by about 10% in pathogen challenged plants. Root mortality caused by infection of P. capsici was completely eliminated by pre-inoculation with antagonistic G. intraradices. On the ninth day after pathogen infection, Peroxidase (POD) activity increased by 116.9% in Pc-treated roots but by only 21.2% in Gi+Pc-treated roots, compared with the control, respectively. Polyphenol oxidase (PPO) and Phenylalanine ammonia-lyase (PAL) activities gradually increased during the first 3 d and dramatically decreased in Pc-treated roots but slightly decreased in Gi+Pc-treated roots, respectively. On the ninth day after pathogen infection, PPO and PAL decreased by 62.8% and 73.9% in Pc-treated roots but by only 19.8% and 19.5% in Gi+Pc-treated roots, compared with the control, respectively. Three major POD isozymes (45,000, 53,000 and 114,000) were present in Pc-treated roots, while two major bands (53,000 and 114,000) and one minor band (45,000) were present in spectra of Gi+Pc-treated roots, the 45,000 POD isozyme was significantly suppressed by G. intraradices, suggesting that the 45,000 POD isozyme was induced by the pathogen infection but not induced by the antagonistic G. intraradices. A 60,000 PPO isozyme was induced in Pc-treated roots but not induced in Gi+Pc-treated roots. All these results showed the inoculation of antagonistic G. intraradices alleviates root mortality, activates changes of lignification-related enzymes and induces some of the isozymes in pepper plants infected by P. capsici. The results suggested that G. intraradices is a potentially effective protection agent against P. capsici.
Capsicum
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cytology
;
enzymology
;
microbiology
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Lignin
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metabolism
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Pest Control, Biological
;
methods
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Phyllachorales
;
cytology
;
physiology
;
Phytophthora
;
cytology
;
physiology
;
Plant Proteins
;
metabolism
9.Survival of the biocontrol agents Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116 on the spikes of barley in the field.
Xin ZHANG ; Bing-xin ZHANG ; Zhen ZHANG ; Wei-feng SHEN ; Ching-hong YANG ; Jing-quan YU ; Yu-hua ZHAO
Journal of Zhejiang University. Science. B 2005;6(8):770-777
Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating disease that results in extensive yield losses to wheat and barley. A green fluorescent protein (GFP) expressing plasmid pRP22-GFP was constructed for monitoring the colonization of two biocontrol agents, Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116, on the spikes of barley and their effect on suppression of FHB. Survival and colonization of the Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116 strains on spikes of barley were observed by tracking the bacterial transformants with GFP expression. Our field study revealed that plasmid pRP22-GFP was stably maintained in the bacterial strains without selective pressure. The retrieved GFP-tagged strains showed that the bacterial population fluctuation accorded with that of the rain events. Furthermore, both biocontrol strains gave significant protection against FHB on spikes of barley in fields. The greater suppression of barley FHB disease was resulted from the treatment of barley spikes with biocontrol agents before inoculation with F. graminearum.
Bacillus
;
classification
;
cytology
;
isolation & purification
;
physiology
;
Cell Survival
;
physiology
;
Fusarium
;
isolation & purification
;
pathogenicity
;
physiology
;
Hordeum
;
microbiology
;
parasitology
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Pest Control, Biological
;
methods
;
Plant Diseases
;
microbiology
;
parasitology
;
Species Specificity
;
Survival Analysis
10.DNA sequence representation by trianders and determinative degree of nucleotides.
Journal of Zhejiang University. Science. B 2005;6(8):743-755
A new version of DNA walks, where nucleotides are regarded unequal in their contribution to a walk is introduced, which allows us to study thoroughly the "fine structure" of nucleotide sequences. The approach is based on the assumption that nucleotides have an inner abstract characteristic, the determinative degree, which reflects genetic code phenomenological properties and is adjusted to nucleotides physical properties. We consider each codon position independently, which gives three separate walks characterized by different angles and lengths, and that such an object is called triander which reflects the "strength" of branch. A general method for identifying DNA sequence "by triander" which can be treated as a unique "genogram" (or "gene passport") is proposed. The two- and three-dimensional trianders are considered. The difference of sequences fine structure in genes and the intergenic space is shown. A clear triplet signal in coding sequences was found which is absent in the intergenic space and is independent from the sequence length. This paper presents the topological classification of trianders which can allow us to provide a detailed working out signatures of functionally different genomic regions.
Algorithms
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Base Sequence
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Chromosome Mapping
;
methods
;
Codon
;
genetics
;
DNA
;
genetics
;
Molecular Sequence Data
;
Nucleotides
;
genetics
;
Sequence Analysis, DNA
;
methods