Quantitative study of iron metabolism-related genes expression in rat / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the multiple iron metabolism-related genes expression, its regulation by iron and the expression correlation among the genes in rat tissues.</p><p><b>METHODS</b>Two groups (n=30) of Sprague-Dawley female weanling rats were fed with a control diet and an iron deficient diet respectively for 4 weeks. All rats were then sacrificed, and blood and tissue samples were collected. The routine blood examination was performed with a veterinary automatic blood cell analyzer. Elemental iron levels in liver, spleen and serum were determined by atomic absorption spectrophotometry. The mRNA expression of genes was detected by real-time fluorescence quantitative PCR.</p><p><b>RESULTS</b>After 4 weeks, the hemoglobin (Hb) level and red blood cell (RBC) count were significantly lower in the iron deficient group compared with those in the control group. The iron levels in liver, spleen and serum in the iron deficient group were significantly lower than those in the control group. In reference to small intestine, the relative expression of each iron-related gene varied in the different tissues. Under the iron deficiency, the expression of these genes changed in a tissue-specific manner. The expression of most of the genes significantly correlated in intestine, spleen and lung, but few correlated in liver, heart and kidney.</p><p><b>CONCLUSION</b>Findings from our study provides new understandings about the relative expression, regulation by iron and correlation among the mRNA expressions of transferrin receptors 1 and 2, divalent metal transporter 1, ferritin, iron regulation proteins 1 and 2, hereditary hemochromatosis protein, hepcidin, ferroportin 1 and hephaestin in intestine, liver, spleen, kidney, heart, and lung of rat.</p>

STUDY ON THE CHARACTERS OF AN HARPIN-PRODUCING BACTERIA STRAIN TOLERANT TO AMMONIUM AND NITROGEN-FIXING / 微生物学通报

The ability to induce hypersensity on leaves of tomato and the stability of double-plasmid of an harpin-producing, nitrogen-fixing engineered strain E4 were tested. Hypelsensitivity-inducing experiment indicated that the time and density of hypersensitivity-induction of E4 was similar to those of DH5, the positive control of pCPP430. Although E4 took the same time to induce hypersensitivity as 308R, another positive control of pCPP430, it induced weaker hypersen- sitivity on tobacco leaves. On tomato leaves, there was no difference in time and density of hypersensitivity between E4 and 308R (pCPP430). Results revealed that the two plasmids, pCPP430 and pMC73A, were unstable in host bacteria, with the losing rate of 100% at the 48th generation. The emergence probability of bacteria with either pCPP430 or pMC73A was almost the same.

IDENTIFICATION OF ENDOPHYTES FROM TOMATO SEEDLINGS AND ANALYSIS OF DNA FINGERPRINTS USING ERIC-PCR / 微生物学通报

A new method of identification and study of diversity of endophytes wa s described in this paper. The seedlings of tomato were treated using four meth o ds, sterile water, chemical reagents, ultraviolet radiation and mechanical to pe el off, respectively. Then endophytes were isolated using plates of beef- pept on e, Gaos I and PDA respectively. The optimal method of wiping off non-endophyte s was determined. We had obtained 148 isolates of endophytes with different size, shape and color. 43 strains of 148 were amplified using method of ERIC-PCR. T he results showed that 32 strains with amplified bands could fall into 28 classes. The purified bacteria were cultured confronting to leaf blight pathogen of tomat o to screen high resistant strain. Three bacteria strains with high resistance to pathogen were obtained.

Genetic Stability of a Recombinant Biocontrol Bacteria 308R(pKSH) / 微生物学通报

Biocontrol bacteria 308R(pKSH) with hrpN of Erwinia amyloyora. It can secrete the Harpin protein which can induce plant resistance. After successive growth in antibiotic-free LB medium for 50 generations, only 23.1% of the cell still retained the plasmid pKSH, in comparison with 4.75% of the cosmid pCPP430. Sprayed onto the leaves of tomato, the recombinant strain maintained a population density of over 10~ 5 cfu/cm~ 2 when kept under high humidity in thirteen days, but if without humidity, the strain keep 10~ 4 cfu/cm~ 2 over in five days. On the tomato leaves, the stability of the recombinant strain 308R(pKSH) was higher than the strain 308R(pCPP430). The experiment indicated that the recombinant strain 308R(pKSH) had higher stability compared with the strain 308R(pCPP430), but that was not enough. In this paper reasons for unstability and strategies for improving were discussed for the recombinant strain.

Effects of Transgenic Biocontrol Bacterium 308R(pCPP430) on Tomato Rhizosphere Bacterial Community / 微生物学通报

The study aimed at investigation the effect of the transgenic biocontrol bacteria 308R(pCPP430) on the tomato rhizosphere bacterial communities. Strain 308R (Pantoea agglomerans), an adnascent bacterium isolated from tomato, was a biocontrol bacterium. The recombinant cosmid pCPP430 contained the hrp gene cluster of Erwinia amylovora was transformed into 308R Strain. Transgenic biocontrol bacterium 308R(pCPP430) produced Harpin protein which induce hypersensitive response and disease resistance in plants and, surprisingly, increase plant growth. Two complementary methods, sole-carbon-source utilization tests (SCSU) and ERIC-PCR, were used to compare the characterization of bacterial communities from three groups of tomato roots dipped in sterilized water, 308R suspended liquid and 308R(pCPP430) suspended liquid. The cluster analysis and principal components analysis of the number of colonies from SCSU indicated consistent differences in the rhizosphere of each group. Cluster analysis of SCSU data showed that there were consistent differences in the rhizosphere of each group. The rhizosphere bacteria communities of root dipped with 308R(pCPP 430) and 308R have a relative good replication, but the differences of corresponding replicates in dipped with distilled water was increased by degrees. Cluster analysis of ERIC-PCR fingerprints revealed that most of results (eight in ten) have overlaps between roots dipped in water and those dipped in 308R liquid. The methods used in this study may prove a useful approach for the comparison of bacterial communities.