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Zhen Zhu

Publications and source records attributed to Zhen Zhu.

At least 19 recordsLinked to original sources
PubMed2025

Frequent Genomic Recombination in the 5'-Proximal Region Characterizes Human Adenovirus Species C Evolution.

To advance our understanding of the molecular recombination dynamics of circulating human adenovirus species C (HAdV-C) strains, whole genome sequence (WGS) analysis of seven strains representing five genotypes (P1H1F1, P1H2F2, P89H5F5, P2H2F2, and Px1/Ps3H1F1) isolated from pediatric severe acute respiratory infection (SARI) cases in China were performed, involving sequence similarity assessment, phylogenetic inference, and recombination mapping. The genomic analysis of seven strains showed substantial nucleotide identity (93.5%-99.2%) and distinct recombination patterns. Further comparative recombinant analysis with eight prototype strains and 214 publicly available strains revealed that strains with high genomic similarity or evolutionary relatedness showed substantial conservation in the posterior genomic regions, while the 5'-proximal ~14 000 bp region, particularly E1 and E2B regulatory and replication-associated genes, displayed significant recombination activity. In addition, identical or similar recombination patterns were found in the genomes of strains with high sequence identity and homology, which had been detected by different surveillance systems, and in multiple provinces in China and other countries. Further analysis revealed an independent evolutionary cluster for two strains (Henan2018-431 and Jilin2019-101), which also harbored fragments of unknown origin within the E3 region, potentially representing novel HAdV-C variants. These findings highlight the critical role of frequent recombination in HAdV-C evolution, particularly in low-diversity genomic regions, and emphasize the importance of WGS-based surveillance for tracking emerging recombinant strains with public health implications.

Humans↗
PubMed2006

Mitochondrial defects and oxidative damage in patients with peripheral arterial disease.

Abnormal mitochondrial function is present in patients with peripheral arterial disease and may contribute to its clinical manifestations. However, the specific biochemical mitochondrial defects and their association with increased oxidative stress have not been fully characterized. Gastrocnemius muscle was obtained from peripheral arterial disease patients (n = 25) and age-matched controls (n = 16) and mitochondrial parameters were measured. Complexes I through IV of the electron transport chain were individually evaluated to assess for isolated defects. Muscle was also evaluated for protein and lipid oxidative changes by measuring the levels of protein carbonyls, lipid hydroperoxides, and total 4-hydroxy-2-nonenal binding and for the activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. Mitochondrial electron transport chain complexes I, III, and IV in arterial disease patients demonstrated significant reductions in enzymatic activities and mitochondrial respiration compared to controls. Oxidative stress biomarker analysis demonstrated significantly increased levels of protein carbonyls, lipid hydroperoxides, and 4-hydroxy-2-nonenal compared to control muscle. Antioxidant enzyme activities were altered, with a significant decrease in superoxide dismutase activity and significant increases in catalase and glutathione peroxidase. Peripheral arterial disease is associated with abnormal mitochondrial function and evidence of significant oxidative stress.

Aged↗
PubMed2006

Associative learning in hierarchical self-organizing learning arrays.

In this paper, we introduce feedback-based associative learning in self-organized learning arrays (SOLAR). SOLAR structures are hierarchically organized networks of sparsely connected neurons that define their own functions and select their interconnections locally. This paper provides a description of neuron self-organization and signal processing. Feedforward processing is used to make necessary correlations and learn the input patterns. Discovered associations between neuron inputs are used to generate feedback signals. These feedback signals, when propagated to the primary inputs, can establish the expected input values. This can be used for heteroassociative (HA) and autoassociative (AA) learning and pattern recognition. Example applications in HA learning are given.

Algorithms↗
PubMed2006

Over-expression of exotic superoxide dismutase gene MnSOD and increase in stress resistance in maize.

To evaluate the effect of over-expressed Mn-superoxide dismutase (MnSOD) on stress resistance in maize, an over-expression vector with MnSOD gene of wheat was constructed and used to transform embryonic calli of elite maize inbred line by gene gun. After screening with a concentration gradient of hygromycin, 9 plants were regenerated from the positive calli and reproduced fertile seeds, 5 of which were shown to be positive by PCR and Southern blot analysis. This result indicated that the exotic gene had been integrated in maize genome. SOD enzyme extracts were separated by non-denatured polyacrylamide gel electrophoresis of gradient concentration. After inhibition with 5 mmol/L H(2)O(2) to FeSOD and Cu/ZnSOD, MnSOD enzyme activity was assayed with nitrotetrazolium chloride blue staining. All the 5 plants shown to be positive in Southern blot had higher MnSOD activity than untransformed control. Electric conductivity of leaf exudate was assayed after damage treatment with methyl viologen. The result suggested that the resistance of the transformed plants to oxidative damage was significantly higher than untransformed control.

Gene Expression Regulation, Enzymologic↗
PubMed2005

Identification of a glyphosate-resistant mutant of rice 5-enolpyruvylshikimate 3-phosphate synthase using a directed evolution strategy.

5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) is a key enzyme in the shikimate pathway and is targeted by the wide-spectrum herbicide glyphosate. Here, we describe the use of a selection system based on directed evolution to select glyphosate-resistant mutants of EPSPS. Using this system, the rice (Oryza sativa) EPSPS gene, mutagenized by Error-Prone polymerase chain reaction, was introduced into an EPSPS-deficient Escherichia coli strain, AB2829, and transformants were selected on minimal medium by functional complementation. Three mutants with high glyphosate resistance were identified in three independent glyphosate selection experiments. Each mutant contained a C(317)-->T transition within the EPSPS coding sequence, causing a change of proline-106 to leucine (P106L) in the protein sequence. Glyphosate resistance assays indicated a 3-fold increase in glyphosate resistance of E. coli expressing the P106L mutant. Affinity of the P106L mutant for glyphosate and phosphoenolpyruvate was decreased about 70-fold and 4.6-fold, respectively, compared to wild-type EPSPS. Analysis based on a kinetic model demonstrates that the P106L mutant has a high glyphosate resistance while retaining relatively high catalytic efficiency at low phosphoenolpyruvate concentrations. A mathematical model derived from the Michaelis-Menten equation was used to characterize the effect of expression level and selection conditions on kinetic (Ki and Km) variation of the mutants. This prediction suggests that the expression level is an important aspect of the selection system. Furthermore, glyphosate resistance of the P106L mutant was confirmed in transgenic tobacco (Nicotiana tabacum), demonstrating the potential for using the P106L mutant in transgenic crops.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed2005

Oral administration of geranylgeranylacetone blunts the endothelial dysfunction induced by ischemia and reperfusion in the rat heart.

It has been shown that geranylgeranylacetone (GGA) protects heart against ischemia/reperfusion injury via enhanced heat shock protein 72 (HSP72) expression in rats. In the present study, we investigated the protective effect of GGA on ischemia/reperfusion-induced endothelial dysfunction. Rats were given oral GGA (GGA group) or vehicle (CON group), and 24 hours later their hearts were removed and placed in the Langendorff apparatus for 30-minute low-flow ischemia followed by 30-minute reperfusion. GGA improved the postischemic functional recovery (P < 0.01), which was abolished by N-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor). NO production during both ischemia and reperfusion were increased in the GGA group, and the acetylcholine (ACh)-induced (endothelium-dependent) vasodilation, measured as the percentage decrease in coronary perfusion pressure after ischemia/reperfusion (14.9 +/- 1.3%), was preserved as compared with that in the CON group (7.9 +/- 1.4%). LY294002, a phosphatidylinositol 3 (PI3) kinase inhibitor, abolished the protective effects of GGA on endothelial-dependent coronary vasodilation and NO production, whereas Y27632 (Rho kinase inhibitor) increased endothelium-dependent coronary vasodilation and NO production in CON group toward the level seen in GGA group. The amount of adrenomedullin in the coronary effluent at basal condition was lower in the GGA group than in the CON group (P < 0.05), and during both ischemia and reperfusion there was no difference in the amount of adrenomedullin between the GGA and CON groups. In addition, no difference was observed in the amount of endothelin-1 between the GGA and CON groups. These results indicate that GGA attenuates the ischemia/reperfusion-induced coronary endothelial dysfunction, which may contribute to its cardioprotective effect. The PI3 kinase and/or Rho kinase pathways appear to be involved in this process, whereas adrenomedullin and endothelin-1 are not necessary for the GGA-induced cardioprotection.

Administration, Oral↗
PubMed2005

Self-organizing learning array.

A new machine learning concept--self-organizing learning array (SOLAR)--is presented. It is a sparsely connected, information theory-based learning machine, with a multilayer structure. It has reconfigurable processing units (neurons) and an evolvable system structure, which makes it an adaptive classification system for a variety of machine learning problems. Its multilayer structure can handle complex problems. Based on the entropy estimation, information theory-based learning is performed locally at each neuron. Neural parameters and connections that correspond to minimum entropy are adaptively set for each neuron. By choosing connections for each neuron, the system sets up its wiring and completes its self-organization. SOLAR classifies input data based on the weighted statistical information from all the neurons. The system classification ability has been simulated and experiments were conducted using test-bench data. Results show a very good performance compared to other classification methods. An important advantage of this structure is its scalability to a large system and ease of hardware implementation on regular arrays of cells.

Learning↗
PubMed2005

[Research of the contents of in vitro protein in the seed of sck transgenic rice].

OBJECTIVE: To detect the expression level of CpTI and HPT proteins in the seed of sck transgenic rice. METHODS: The seeds of T6 sck transgenic rice were detected by PCR. The CpTI and HPT proteins in the seeds, stems, roots and leaves of positive plants were detected by Western blot. The CpTI and HPT proteins in the seeds of positive plants and the control plants were detected by double sandwich ELISA. RESULTS: hpt and sck genes were found in T6 sck rice. The CpTI and HPT proteins were positive in the leaves, stems, and roots in Western blot analysis, and negative in the seeds. The content of CpTI protein is lower than LLD of double sandwich ELISA (< 14 ug/L), and HPT protein could not be detected. CONCLUSION: The content of CpTI protein in the seeds of T6 sck rice is lower than LLD of double sandwich ELISA, and HPT protein could not be detected.

Oryza↗
PubMed2005

[Expression specificity of hpt gene in sck transgenic rice].

OBJECTIVE: Evaluate the expression specificity of hpt gene in different developmental stages of sck transgenic rice. METHODS: The different tissues, including leaves, culms, roots and seeds (ripening stage), in different developmental stages of sck transgenic rice were detected by PCR. The positive plants and the control plants were detected by Northern blot analysis and double sandwich ELISA test. RESULTS: The hpt gene expression was found at transcription level and translation level in different tissues of sck transgenic rice. HPT protein in the seeds could not be detected. CONCLUSION: The hpt gene in different developmental stages of sck transgenic rice express stably at transcription level and translation level and HPT protein in the seeds could not be detected.

Gene Expression Regulation, Plant↗
PubMed2005

Elevated plasma tissue-type plasminogen activator (t-PA) and soluble thrombomodulin in patients suffering from severe acute respiratory syndrome (SARS) as a possible index for prognosis and treatment strategy.

OBJECTIVE: To detect the presence of endothelial injury in patients with severe acute respiratory syndrome (SARS) via enhanced levels of tissue-type plasminogen activator (t-PA) and soluble thrombomodulin (sTM). METHODS: Case patients were from Xuanwu Hospital (Capital University of Medical Sciences, Beijing, China), and all of them met clinical criteria for SARS. Healthy controls were some of the hospital employees. Endothelial injury bio-markers tPA and sTM were detected by commercial ELISA-methods. RESULTS: Classic plasma markers of endothelial injury, tPA and sTM significantly elevated in SARS patients in comparison to controls [t-PA: 1.48 +/- 0.16 nmol/L versus 0.25 +/- 0.03 nmol/L (P<0.0001), and sTM: 0.26 +/- 0.06 nmol/L versus 0.14 +/- 0.02 nmol/L (P<0.05)]. The only patient who died had extremely high levels of these endothelial injury markers (t-PA: 2.77 nmol/L and sTM: 1.01 nmol/L). The likelihood ratio analysis indicated the excellent discriminating power for SARS at the optimal cut-point of 0.49 nmol/L for tPA and 0.20 nmol/L for sTM, respectively. Significant numerical correlations were found among these endothelial injury markers in SARS patients. The numerical coefficient of correlation Pearson r between t-PA and sTM was 0.5867 (P<0.05). CONCLUSION: Increased plasma concentrations of tPA and sTM in patients with SARS suggest the possibility of endothelial injury. SARS patients might need anticoagulant therapy or fibrinolytic therapy in order to reverse intraalveolar coagulation, microthrombi formation, alveolar and interstitial fibrin deposition. It may not only provide a useful treatment and prognostic index but also allow a further understanding of the pathological condition of the disease.

Adult↗
PubMed2005

Preparation of monoclonal antibody against HPT and its application to detecting marker protein in genetically modified rice.

OBJECTIVE: To produce the monoclonal antibodies (mAbs) against hygromycin B phosphotransferase (HPT) and to develop immunoassay based on mAbs for biosafety assessment of HPT in genetically modified rice (GM rice). METHODS: BALB/c mice were immunized with purified recombinant 6His. HPT protein, and the conventional hybridoma technology was used to generate the monoclonal hybridoma cells. ELISA and Western blot were used to analyze the specificity of mAbs recognizing HPT and the cross reaction with other proteins. A double-Ab sandwich ELISA method was established to detect HPT expression level in the sck gene-modified rice plants. RESULTS: Four hybridomas, named F1, D4-2, D4-4, and D4-5, producing the mAbs against HPT were successfully obtained with the titer of ascetic mAbs ranging from 1x10(-4) to 1x10(-5). Identification of subclass showed that all the produced mAbs belonged to IgG1. Western blot showed specific binding reaction between the mAbs to the HPT proteins expressed in the GM rice. A double sandwich ELISA coated with anti-HPT polyclonal antibody was established with mAbs as sandwich antibody, which showed a sensitivity of 30ng/mL and did not crossreact with other proteins. The expression level of HPT in the leaves of sck-transformed lines was detected (80-150ng/mL). But HPT protein in the grain and seed of GM rice could not be detected using this ELISA assay. CONCLUSION: Anti-HPT mAbs prepared herein have a high specificity and can be used for rapid assay of HPT antigen. The expression level of HPT in the GM rice grain and seed is lower than our ELISA detection limit.

Animals↗
PubMed2004

Green fluorescent protein as a vital elimination marker to easily screen marker-free transgenic progeny derived from plants co-transformed with a double T-DNA binary vector system.

We investigated the potential of a novel double T-DNA vector for generating marker-free transgenic plants. Co-transformation methods using a double T-DNA vector or using mixture of two Agrobacterium tumefaciens strains were compared, and showed that the double T-DNA vector method could produce marker-free transgenic tobacco (Nicotiana tabacum L.) plants more efficiently. A dual marker double T-DNA vector was then constructed by assembling the green fluorescent protein (GFP) gene mgfp5 and the neomycin phosphotransferase gene nptII into the same T-DNA. The frequency of co-transformants produced by this vector was 56.3%. Co-expression of mgfp5 and nptII was found in 28 out of 29 T1 lines, and segregation of the reporter beta-glucuronidase gene, gusA, from mgfp5 to nptII was found in 12 out of 29 T1 lines. Therefore, GFP could be used as a vital marker to improve the transformation efficiency and to easily monitor the segregation of marker genes, thus facilitating screening of marker-free progeny.

Agrobacterium tumefaciens↗
PubMed2004

Cardiac sympathetic afferent stimulation impairs baroreflex control of renal sympathetic nerve activity in rats.

It is well known that cardiac sympathetic afferent reflexes contribute to increases in sympathetic outflow and that sympathetic activity can antagonize arterial baroreflex function. In this study, we tested the hypothesis that in normal rats, chemical and electrical stimulation of cardiac sympathetic afferents results in a decrease in the arterial baroreflex function by increasing sympathetic nerve activity. Under alpha-chloralose (40 mg/kg) and urethane (800 mg/kg i.p.) anesthesia, renal sympathetic nerve activity, mean arterial pressure, and heart rate were recorded. The arterial baroreceptor reflex was evaluated by infusion of nitroglycerin (25 microg i.v.) and phenylephrine (10 microg i.v.). Left ventricular epicardial application of capsaicin (0.4 microg in 2 microl) blunted arterial baroreflex function by 46% (maximum slope 3.5 +/- 0.3 to 1.9 +/- 0.2%/mmHg, P < 0.01). When the central end of the left cardiac sympathetic nerve was electrically stimulated (7 V, 1 ms, 20 Hz), the sensitivity of the arterial baroreflex was similarly decreased by 42% (maximum slope 3.2 +/- 0.3 to 1.9 +/- 0.4%/mmHg; P < 0.05). Pretreatment with intracerebroventricular injection of losartan (500 nmol in 1 microl of artificial cerebrospinal fluid) completely prevented the impairment of arterial baroreflex function induced by electrical stimulation of the central end of the left cardiac sympathetic nerve (maximum slope 3.6 +/- 0.4 to 3.1 +/- 0.5%/mmHg). These results suggest that the both chemical and electrical stimulation of the cardiac sympathetic afferents reduces arterial baroreflex sensitivity and the impairment of arterial baroreflex function induced by cardiac sympathetic afferent stimulation is mediated by central angiotensin type 1 receptors.

Animals↗
PubMed2004

[Obtainment of transgenic wheat with the insecticidal lectin from snowdrop (Galanthus nivalis agglutinin; GNA) gene and analysis of resistance to aphid].

Snowdrop lectin (Galanthus nivalis agglutinin; GNA) is toxic to sap sucking injurious insects of Homopteran. A new gna gene has been transferred into common spring wheat Zhong60634 and winter wheat Yumai66 with high yield by using the biolistic transformation method. Transgenic wheat plants have been obtained in both of the two varieties. Two transgenic plants (T0) have been obtained from the bombarded 535 immature embryos of Zhong60634. Bioassay results show that the development of aphid could be slowed down and the survival rate of young aphid could be reduced by gna gene. Seventeen transgenic plants (T0) were obtained from the bombarded 4636 immature embryos of Yumai66. Twenty plantlets with good resistance to Rhopalosiphum padi and Macrosiphum avenae, which are mainly aphid in north wheat area, were identified from the transgenic plants of T1 generation that came from 8 T0 transgenic plants with good resistance to aphid. The anti-aphid bioassay shows that resistance to the different grain aphid is not the same in transgenic wheat plants. To Rhopalosiphum padi, the rate of survival aphid 8 days after exposing transgenic plants to aphids is significantly lower than that of nontransgenic plants. To Macrosiphum avenae, growth speed of aphids is slowed down but not killed. At the same time, the death rate of young aphids is increased. Anyway, feeding of the two kinds of aphids has been controlled in a certain degree by gna gene when aphids can free to move in plants.

Animals↗
PubMed2004

[Relationship between genetic lineage and pathotype of Pyricularia grisea in Yunnan Plateau].

Rice blast caused by Pyricularia grisea is the most destructive disease in Yunnan Plateau, China. In order to elucidate the relationship between genetic lineage and pathotype of P. grisea of Yunnan Plateau as well as the variability of the fungus at DNA level,the repetitive element-based PCR (rep-PCR) of Pot2, an element found in approximately 100 copies in the fungus genome,was exploited. Two hundred and thirty-six isolates of P. grisea collected from 15 main rice-growing counties of Yunnan Plateau were fingerprinted by using rep-PCR. A linkage graph of the rep-PCR fingerprints from 134 representative isolates was generated using an unweighted pair-grouped average program (UPGMA) of the STATISTICAL 5.0 software. The isolates were classified into 8 genetic lineages (G1 approximately G8) at the level of 1.75 genetic linkage distance, of which the G1, G2 and G4 were the dominant lineages. The isolates in a certain area generally belonged to one correspondent genetic lineage and the isolates from the same plot and host rice variety mostly shared one linkage group though different genetic lineages within one lesion. Furthermore, 29 isolates representing the eight genetic lineages were inoculated on 33 rice cultivars of Yunnan at the stage of 3 approximately 4 leaves in greenhouse. The isolates were divided into 6 pathotype groups (P1 approximately P6) according to its compatibility, which demonstrated that some isolates of one genetic lineage sharing two or three pathotype groups, alternatively, one or four pathotype groups. The isolates from each genetic lineage, however, may share one pathotype group such as P2. The preliminary results implicated that the relationship between genetic lineages and pathotype groups of P. grisea in Yunnan Plateau was complicated rather than simple. On the other hand,2 rice cultivars including HeXi 16 and JingGuo 92 were resistant to the 29 isolates but YunJing 20 and HeXi 30 both susceptible to all of them, which was helpful for deploying the blast-resistant genes in rice production of Yunnan Plateau. Therefore, the rice blast-resistance spectrum of the tentative new rice cultivars should be evaluated before its release considering the blast-resistant rice breeding and the practice of rice production in Yunnan Plateau.

Ascomycota↗
PubMed2003

A metallothionein-like gene htMT2 strongly expressed in internodes and nodes of Helianthus tuberosus and effects of metal ion treatment on its expression.

A cDNA sequence encoding a type-2 metallothionein (MT)-like protein, designated htMT2, was isolated from a Helianthus tuberosus L. tuber cDNA library. The isolated cDNA is 509 bp, coding a 7.8-kDa polypeptide. Two partial genomic fragments covering the open reading frame of htMT2 were cloned by PCR. The fragments htMTG-1 (986 bp) and htMTG-2 (982 bp) contain three exons and two introns. The N- and C-terminal domains of the predicted polypeptide have eight and seven cysteine residues, separated by a central cysteine-free spacer. Sequence alignment revealed that the predicted protein was homologous to type-2 MTs of plants. Southern blot analysis indicated that htMT2 is encoded by a small multi-gene family in the H. tuberosus genome. Northern blot analysis showed that htMT2 transcripts were predominantly expressed in internodes and nodes, but were low in leaves, leafstalks, tubers and young roots, and none was detected in roots. Treatment with Cu(2+) reduced the expression of htMT2 in internodes, nodes, leaves and leafstalks. In addition, the expression levels in internodes and nodes share an inverse relationship with the concentrations of Cu(2+). In internodes and nodes, treatment with Zn(2+) at 10 and 100 microM reduced the expression levels of htMT2, and 1000 microM Zn(2+)reduced it to the lowest level, but 500 microM Zn(2+) had little effect. The expressions of htMT2 in different tissues were not appreciably affected by heat shock. It is suggested that HtMT2 might be involved in the transport or availability of Cu(2+) and Zn(2+) to some apo-metal enzymes or apo-metal proteins.

Amino Acid Sequence↗