[Absorption and Transportation of Selenium Nanoparticles in Wheat and Rice].

Hydroponics experiments were carried out to study the effects of different sizes of selenium nanoparticles (SeNPs) and different pH on the absorption and transportation of Se by wheat (Triticum aestivum L.) and rice (Oryza sativa L.). The results showed that SeNPs with different sizes (50, 100, and 150 nm) had various characteristics with respect to absorption and translocation in wheat and rice. There was no significant difference in the uptake of SeNPs with different sizes by wheat roots after 24 h and 72 h; however, the highest Se content in wheat shoots was (1.89±0.47) µg·g-1 dry weight (DW) and (5.18±1.51) µg·g-1 DW under the 50 nm SeNPs treatment after 24 h and 72 h, respectively. Moreover, the transfer factor for Se in wheat under the 50 nm SeNPs treatment was 2.38 times higher than that of the 100 nm and 150 nm treatments. The Se content of rice roots treated for 24 h with the 50 nm SeNPs increased by 11.18% and 41.81% compared to those treated with the 100 nm and 150 nm SeNPs, respectively. There were, however, no significant differences in Se content between all of the SeNPs treatments after 72 h. The Se content of rice shoots and the Se transfer factor both reached the maximum when 50 nm SeNPs were applied. In addition, Se absorption by plants was also affected by pH. Specifically, the amount of Se absorbed by wheat roots treated with SeNPs was the greatest at a pH of 6 after 24 h, which was 89.47% higher than wheat treated with selenite. Furthermore, the highest Se transfer factor occurred at a pH of 4 in wheat. The uptake of SeNPs in rice was markedly lower than that of selenite at low pH values (pH=3.5 and 5.5) and SeNPs was more readily transported at a pH of 3.5. These results demonstrate that SeNPs could be taken up by wheat and rice and that it could be transferred more easily as small particle size (50 nm) than the larger ones (100 nm and 150 nm) at low pH values (pH 3.5).

[Remote sensing detection of vegetation health status after ecological restoration in soil and water loss region]. / 水土流失区生态修复后植被健康的遥感判别.

This paper proposed a vegetation health index (VHI) to rapidly monitor and assess vegetation health status in soil and water loss region based on remote sensing techniques and WorldView-2 imagery. VHI was constructed by three factors, i.e., the normalized mountain vegetation index, the nitrogen reflectance index and the reflectance of the yellow band, through the principal component transformation, in order to avoid the deviation induced by subjective method of weighted summation. The Hetian Basin of Changting County in Fujian Province, China, was taken as a test area to assess the vegetation health status in soil and water loss region using VHI. The results showed that the VHI could detect vegetation health status with a total accuracy of 91%. The vegetation of Hetian Basin in good, moderate and poor health status accounted for 10.1%, 49.2% and 40.7%, respectively. The vegetation of the study area was still under an unhealthy status because the soil was poor and the growth of newly planted vegetation was not good in the soil and water loss region.

[Impact of land use change and cultivation measures on soil organic carbon (SOC) and its 13C values].

In Quzhou County, Hebei Province where now intensive farming system is operated, original grassland and farming land under different tillage, crop straw return and fertilization measures were studied using isotope carbon for the analysis of the impact on soil organic carbon (SOC) properties. The research indicated that after change into farmland (34 years), SOC is significantly reduced and for 1 m of soil layer, the scope of reduction is from 13.3%-35% and this decrease happens in 0-40 cm of soil layer. After 8 years of fertilization, SOC can be increased at 0.83 g x kg(-1). No-tillage can significantly increase the SOC especially in 0-10 cm but plough will increase the SOC at 10-15 cm and 15-20 cm. Change of delta13 C of SOC due to land use change mainly happens in 0-20 cm, where input of organic materials from maize stored. In soil layer of 0-5 cm, only maximum 18% of SOC is from crop residues and in 15-20 cm, this percentage is about 5%.

Mutations that disrupt either the pqq or the gdh gene of Rahnella aquatilis abolish the production of an antibacterial substance and result in reduced biological control of grapevine crown gall.

Rahnella aquatilis HX2, a biocontrol agent for grapevine crown gall caused by Agrobacterium vitis, produces an antibacterial substance that inhibits the growth of A. vitis in vitro. In this study, we show that MH15 and MH16, two Tn5-induced mutants of HX2, have lost their abilities to inhibit A. vitis and have reduced biocontrol activities; they grow in logarithmic phase at a rate similar to that of the wild type and have single Tn5 insertions. They are also impaired in producing pyrroloquinoline quinone (PQQ) or glucose dehydrogenase (GDH). Complementation of MH15 and MH16 with cosmid clones of CP465 and CP104 from an HX2 DNA library restored the antibiosis, biocontrol, and PQQ or GDH production phenotypes. A 6.7-kb BamHI fragment from CP465 that fully restored the MH15-affected phenotypes was cloned and sequenced. Sequence analysis of the mutated DNA region resulted in the identification of seven open reading frames (ORFs), six of which share significant homology with PQQ-synthesizing genes in other bacteria, designated pqqA through pqqF. Meanwhile, A 5.5-kb PstI fragment from CP104 fully complemented the MH16 mutant and contained a single ORF highly similar to that of genes coding for GDHs. An in-frame gdh deletion mutant has the same phenotypes as the Tn5 mutant of MH16. Complementation of both deletion and Tn5 gdh mutants restored the affected phenotypes to wild-type levels. Our results suggest that an antibacterial substance plays a role in biocontrol of A. vitis by HX2.

[Chest X-ray features of severe acute respiratory syndrome and clinical staging].

OBJECTIVE: To establish a clinical staging system for patients with severe acute respiratory syndrome (SARS) based on clinical feature, laboratory tests as well as dynamic changes of chest X-ray images. METHOD: Dynamic changes of chest X-ray images and laboratory tests in 45 SARS patients managed from March to May, 2003 were analyzed. RESULTS: (1) Chest X-ray image: among 45 cases, 23 were common type: the time to appearance of unilateral patched shadow of the lung were 2 to 5 (2.9 +/- 1.0) days. The time to appearance of bilateral patched shadow of the lungs were 2 to 12 (6.9 +/- 2.5) days. The time to appearance of ground glass or consolidation in the lung were 6 to 19 (11.0 +/- 2.0) days. The time to the beginning of absorption of X-ray changes were 10 to 21 (15.0 +/- 4.1) days. The time for chest X-ray image to be absorbed completely were 18 to 46 (25.9 +/- 7.2) days. Twenty-two patients were severe type, in which the time to the appearance of ground glass of the lung were (9.0 +/- 3.2) days, with no significant difference when compared with common type (P < 0.05). However, the time to the beginning of absorption and complete absorption were (19.0 +/- 4.6) days (P = 0.009) and (36.0 +/- 8.1) days (P = 0.001), respectively. Noticeably, the time to pan-consolidation of the lung were less than 7 days in 7 fatal cases. (2) Laboratory tests: decrease in the number of lymphocytes and T lymphocyte subset were seen in the early stage. While the account recovered in 10 to 14 days of disease course in the 38 patients who survived, there was no recovery in 7 patients who died. CONCLUSIONS: SARS can be divided into five stages: incubation period 2 to 10 days, prodromal period 1 to 3 days, progressive period 4 to 7 days, advanced period 8 to 15 days were, convalescent period 16 to 24 days. The appearance of pan-consolidation in the lung in less than 7 days and/or unable to recover the number of lymphocytes and T lymphocyte subset will be associated with poor prognosis.

[Clinical manifestation, treatment, and outcome of severe acute respiratory syndrome: analysis of 108 cases in Beijing].

OBJECTIVE: To investigate the clinical manifestations, treatment, and outcome of severe acute respiratory syndrome (SARS). METHODS: The clinical data of 108 SARS in-patients were analyzed. RESULTS: Among the 108 cases, 35 males (32.4%) and 73 females (67.6%), aged 37 +/- 9 (range 13 approximately 83 years), most were white-collar workers, medical workers accounting for 28.7%. 87.0% had a definite contact history. 20.4% were complicated by other internal diseases. The main clinical manifestations included fever, cough, pectoralgia, chest distress, headache, etc. Involvement of multiple organs was often. The incubation period was 2 approximately 14 days. The course included early stage, progressive stage, climax, and convalescence. Mild type accounted for 4.6%, common type 39.8%, severe type 20.4%, and extremely severe type 35.2%. At the early stage, white blood cell count, lymphocyte count and ratio of lymphocyte, proalbumin, transferring, CD(3)(+), CD(4)(+), CD(8)(+) cell count were remarkably decreased, and C-reactive protein, alpha-acid glycoprotein, and alpha(2)-globulin were remarkably increased. X-ray chest film showed solitary or multiple local exudative changes, mostly in pulmonary lower field. During the progressive stage the hyaline or consolidation images were enlarged. High solution CT showed solitary or multiple cotton wadding like images and ground glass-like or consolidation images. Hypoxemia was common. At the progressive stage application of adrenocortical hormones and non-invasive mechanical ventilation helped stop the progress of disease. Ninety-four cases were discharged, 14 cases died. Traditional Chinese medicine (TCM) regards SARS as one of epidemic febrile diseases. Treatment by combination of TCM and Western medicine was effective. CONCLUSION: SARS mainly affects youth and people in their prime of life. It has its own characteristic clinical manifestations. The classification system of 5 types and 4 stages helps judge the condition. Treatment by combination of TCM and Western medicine is encouraged.

[Use of glucocorticoid in treatment of severe acute respiratory syndrome cases].

OBJECTIVE: To explore the effect of glucocorticoid in the treatment for severe acute respiratory syndrome (SARS). METHODS: Clinical data of 70 patients with SARS admitted to Youan Hospital in Beijing during March to May, 2003 were analyzed. RESULTS: (1) Sixty-three of 70 cases of SARS recovered and seven cases died, with a case-fatality ratio of 10%. (2) Average length of hospital stay was 16.9 days for the all 70 cases, and 16.8 days for the 11 cases without glucocorticoid treatment, without statistical significance (F = 1.018, P = 0.39). (3) The other 59 cases were administered with 40 mg to 640 mg of methylprednisolone daily. (4) Average hospital stay was 15 days for the 23 cases with lower dose of 40 mg to 80 mg methylprednisolone daily, 18.5 days for the 27 cases with medium dose of 120 mg to 240 mg daily, and 17.9 days for the nine cases with higher dose of 320 mg to 640 mg daily (F = 1.018, P = 0.39). CONCLUSIONS: Earlier use of glucocorticoid therapy with suitable doses could alleviate their clinical symptoms, improve their clinical courses, and promote the absorbance of infiltration in their lungs on chest-X-ray films for the cases with SARS. However, current clinical data showed that glucocorticoid therapy could not shorten the length of hospitalization for the cases with SARS.

[Detection of the mutation in HBV polymerase gene by RFLP PCR method in hepatitis B patients treated with lamivudine].

BACKGROUND: To investigate the mutation of HBV polymerase gene in chronic hepatitis B patients treated with lamivudine. METHODS: The restriction-fragment-length-polymorphism (RFLP) assay for HBV DNA sequence determination at the codon 528 and 552 in the HBV polymerase gene associated with lamivudine resistance in vitro. HBV DNA samples extracted from sera of 240 patients were subjected to PCR amplification with primer pairs F2/R2 (552), F3/R2 (528). Each PCR product was digested with Nde I or Nla III. RESULTS: Serum HBV DNA mutation was found in 51/240 patients (38/51M552V, 26/38L528M, 13/51M552I) after therapy for 52 weeks. DNA sequence analysis was performed on samples of 3 patients, and the results were consistent with those of RFLP assay. CONCLUSION: The RFLP assay was able to detect the mutation of HBV DNA at codon 552 and 528 which are the principal site of HBV DNA resistant to lamivudine. The specific PCR method for HBV DNA mutation is rapid, simple and specific.

[A clinical research on oxymatrine for the treatment of chronic hepatitis B].

OBJECTIVE: To investigate the clinical effect of oxymatrine on chronic viral hepatitis B and to look for new methods for treating hepatitis B. METHODS: Multi-center, controlled study was used. In this study, 196 patients were allocated to oxymatrine, oxymatrine with Ara-AMP, IFN-a1b, and glucose groups to observe ALT, AST and viral marker changes. RESULTS: At the end of treatment, the rate of normal ALT, the negative rate of HBV DNA and HBeAg, and the positive rate of HBeAb were similar in oxymatrine, oxymatrine with Ara-AMP, and IFN-a1b groups. It was higher than that of glucose group. After 12 months follow up, the total effective rate is 40.8%, 60.8% and 43.1% in oxymatrine, oxymatrine with Ara-AMP, and IFN-a1b groups, respectively. CONCLUSIONS: Oxymatrine, oxymatrine with Ara-AMP, and IFN-a1b are effective to treat hepatitis B with a good negative rate of HBV DNA and HBeAg and positive rate of HBeAb.