Regulation of photosynthetic function and reactive oxygen species metabolism in sugar beet (Beta vulgaris L.) cultivars under waterlogging stress and associated tolerance mechanisms.

Sugar beet (Beta vulgaris L.) is an economically important sugar crop worldwide that is susceptible to sudden waterlogging stress during seedling cultivation, which poses a major threat to sugar beet development and production. Our understanding of the physiological basis of waterlogging tolerance in sugar beet is limited. To investigate the photosynthetic adaptation strategies of sugar beet to waterlogging stress conditions, the tolerant cultivar KUHN1260 (KU) and sensitive cultivar SV1433 (SV) were grown under waterlogging stress, and their photosynthetic function and reactive oxygen species (ROS) metabolism were assessed. Our results showed that waterlogging stress significantly reduced the photosynthetic pigment content, rubisco activity, and expression level of the photosynthetic enzyme genes SvRuBP, SvGAPDH, and SvPRK, gas exchange parameters, and chlorophyll fluorescence parameters, induced damage to the ultrastructure of the chloroplast of the two sugar beet cultivars, inhibited the photosynthetic carbon assimilation capacity of sugar beet leaves, damaged the structural stability of photosystem II (PSII), and disturbed the equilibrium between electrons at the acceptor and donor sides of PSII, which was the result of stomatal and non-stomatal limiting factors. Moreover, the level of ROS, H2O2, and O2▪-, antioxidant enzyme activity, and gene expression levels in the leaves of the two sugar beet cultivars increased over time under waterlogging stress; ROS accumulation was lower and antioxidant enzyme activities and gene expression levels were higher in the waterlogging-tolerant cultivar (KU) than the waterlogging-sensitive cultivar (SV). In sum, these responses in the more tolerant cultivars are associated with their resistance to waterlogging stress. Our findings will aid the breeding of waterlogging-tolerant sugar beet cultivars.

Melatonin modulates the tolerance of plants to water stress: morphological response of the molecular mechanism.

Water stress (drought and waterlogging) leads to an imbalance in plant water distribution, disrupts cell homeostasis, and severely inhibits plant growth. Melatonin is a growth hormone that plants synthesise and has been shown to resist adversity in many plants. This review discusses the biosynthesis and metabolism of melatonin, as well as the changes in plant morphology and physiological mechanisms caused by the molecular defence process. Melatonin induces the expression of related genes in the process of plant photosynthesis under stress and protects the structural integrity of chloroplasts. Exogenous melatonin can maintain the dynamic balance of root ion exchange under waterlogging stress. Melatonin can repair mitochondria and alleviate damage caused by reactive oxygen species and reactive nitrogen species; and has a wide range of uses in the regulation of stress-specific genes and the activation of antioxidant enzyme genes. Melatonin improves the stability of membrane lipids in plant cells and maintains osmotic balance by regulating water channels. There is crosstalk between melatonin and other hormones, which jointly improve the ability of the root system to absorb water and breathe and promote plant growth. Briefly, as a multifunctional molecule, melatonin improves the tolerance of plants under water stress and promotes plant growth and development.

Waterlogging stress alters the structure of sugar beet rhizosphere microbial community structure and recruiting potentially beneficial bacterial.

Waterlogging has been shown to have a significant inhibitory effect on plant growth. However, the response mechanisms of the soil environment of sugar beet seedlings under waterlogging conditions still need to be fully understood. This study aimed to investigate the effects of waterlogging treatments on the content of effective nutrients and the microbial communities in the rhizosphere and non-rhizosphere using high-throughput sequencing. We set up waterlogging and non-waterlogging treatments, sampled sugar beet seedlings after 10 days of waterlogging, determined the effective soil nutrients in the rhizosphere and non-rhizosphere of the plants, and analyzed the differences in microbial diversity at ten days of waterlogging. The results showed that waterlogging significantly affected available potassium (AK) content. The Ak content of waterlogged soil was significantly higher than that of non-waterlogged soil. Waterlogging caused no significant difference in available nitrogen (AN) content and pH. Moreover, the plant growth-promoting bacteria Pseudomonas was significantly enriched in sugar beet waterlogged rhizospheres compared with the non-waterlogged ones. Similarly, the harmful fungi Gibellulopsis and Alternaria were enriched in sugar beet non-waterlogged rhizosphere. The network analysis revealed that waterlogging built a less complex root-microbial network than non-waterlogging. These findings implied that sugar beets subjected to waterlogging stress were enriched with beneficial microorganisms in the rhizosphere, potentially alleviating the stress.

The response of sugar beet rhizosphere micro-ecological environment to continuous cropping.

Continuous cropping can lead to increased soil-borne diseases of sugar beet (Beta vulgaris L.), resulting in a reduction in its yield quality. However, our understanding of the influence of continuous cropping on sugar beet-associated microbial community is limited and their interactions remain unclear. Here, we described and analyzed microbial diversity (N = 30) from three sugar beet belowground compartments (bulk soil, rhizosphere soil, and beetroot) using 16S rRNA and ITS sequencing. The continuous cropping showed lower bacterial alpha diversity in three belowground compartments and higher fungal alpha diversity in roots compared to the non-continuous cropping. There were significant differences in fungal community composition between the two groups. Compared with non-continuous cropping, continuous cropping increased the relative abundance of potentially pathogenic fungi such as Tausonia, Gilbellulopsis, and Fusarium, but decreased the relative abundance of Olpidium. The fungal flora in the three compartments displayed different keystone taxa. Fungi were more closely related to environmental factors than bacteria. Overall, changes in microbial diversity and composition under continuous cropping were more pronounced in the fungal communities, and the results of the study could guide development strategies to mitigate continuous crop adversity.

Growth status and physiological changes of sugar beet seedlings in response to acidic pH environments.

Sugar beet (Beta vulgaris L.) is an important sugar crop that is popularly cultivated in a variety of agriculture conditions. Here, we studied sugar beet growth in different pH soils (pH 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, and 9.0) and analyzed their growth status and physiology. Sugar beet growth was best at pH 9.0 and worst at pH 5.0. As the soil pH decreased from 9.0 to 5.0, the osmoregulatory substances, antioxidant enzyme activity, and elemental contents in leaves and roots showed increasing trends, while photosynthesis and macronutrient contents showed decreasing trends. To explore the physiological mechanisms sugar beet use to respond to different pH environments, we analyzed the correlations between leaf net photosynthesis rate and physiological changes and nutrient contents of sugar beet. One of the factors inhibiting sugar beet growth in low pH soils was a reduction in photosynthetic capacity. The accumulation of osmoregulatory substances and increased peroxidative damage may have led to the decrease in leaf net photosynthesis rate. Furthermore, the decrease in nutrient content and accumulation of metal elements were correlated with the decrease in leaf photosynthetic rate. QRT-PCR analysis showed higher expression levels of antioxidant enzyme genes in the leaves and roots of sugar beet grown in low pH environments compared to those in high pH environments. Correspondingly, antioxidant enzyme activity was significantly higher in beets in low pH environments than in beets in high pH environments. These results provide important insight into the physiological responses by which sugar beet can adapt to different pH soils.

Factors Associated With Informational Support in Transitional Care for Older Adults With Chronic Diseases: A Cross-Sectional Study.

To evaluate the current situation and associated factors of informational support for older adults with chronic diseases in transitional care. Study was conducted in five hospitals of five different cities in Jiangsu Province, China. A random cluster sample of 800 older adults with chronic diseases responded to the informational support questionnaire of transitional care survey. Descriptive analysis, t-tests, variance analysis, and stepwise multiple linear regression were used to analyze data. The STROBE statement for observational studies was applied. Total score of ISQTC for older adults with chronic diseases was (44.05 ± 17.21). Marital status, educational level, past occupation, close friends, medical insurance, complications, and exercise habits were significantly correlated with informational support. The level of informational support in transitional care for older adults with chronic diseases was low. Clinical staff should periodically and primarily assess their informational support, help find information resources for those who have low initial informational support, and identify which information they preferred to carry out accurate transitional care.

Analysis of the Status Quo and Influencing Factors of Community Residents' Awareness of Basic Life Support and Willingness to Attempt Rescue.

OBJECTIVE: This study aimed to investigate community residents' awareness of basic life support (BLS) and their willingness to attempt rescue. METHODS: From October to December 2020, in the communities of Nantong City, a stratified three-stage random sampling method was adopted to select residents from 12 neighborhood committees over the age of 18 with whom to conduct a cross-sectional questionnaire survey. A self-designed questionnaire was adopted, the contents of which included the general situation of the respondent, knowledge, attitude, and behavior in relation to BLS; the Cronbach's α coefficient of the questionnaire was 0.719. RESULTS: A total of 3000 questionnaires were distributed, of which 2812 were valid, with a valid response rate of 93.73%. Of the 2812 respondents, 41.18% had seen an automatic external defibrillator (AED), 48.83% had experience of' cardiopulmonary resuscitation (CPR), and 25.07% of the respondents had experience of' AEDs. When an accident occurred, 50.50% of residents were willing to attempt rescue, 70.80% were willing to attempt rescue under professional guidance, and 71.23% were willing to attempt rescue after learning BLS techniques. Of the residents who were unwilling to attempt rescue, 32.75% were worried about their lack of ability, 27.91% were concerned about legal issues, 14.01% feared infectious diseases, and 10.35% were unwilling to perform mouth-to-mouth artificial respiration. Age, occupation, education level, and whether they had participated in first aid training were the influencing factors. CONCLUSION: Residents in Nantong have less knowledge of BLS, and their knowledge of CPR is better than that of AEDs. Residents have a strong willingness to learn BLS. Measures need to be taken to improve their understanding of BLS and their application skills. Residents have high levels of willingness to attempt rescue, but a certain percentage of residents have concerns. Interventions can be made to target the different reasons.

Physiological and Proteomic Analysis of Different Molecular Mechanisms of Sugar Beet Response to Acidic and Alkaline pH Environment.

Soil pH is a major constraint to crop plant growth and production. Limited data are available on sugar beet growth status under different pH conditions. In this study, we analyzed the growth status and phenotype of sugar beet under pH 5, pH 7.5, and pH 9.5. It was found that the growth of sugar beet was best at pH 9.5 and worst at pH 5. The activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves and roots increased as pH decreased from 9.5 to 5. Moreover, compared with pH 9.5, the levels of soluble sugar and proline in leaves increased significantly at pH 5. To explore the mechanisms of sugar beet response to different soil pH environments, we hypothesized that proteins play an important role in plant response to acidic and alkaline pH environment. Thus, the proteome changes in sugar beet modulated by pH treatment were accessed by TMT-based quantitative proteomic analysis. A total of three groups of differentially expressed proteins (DEPs) (pH 5 vs. pH 7.5, pH 9.5 vs. pH7.5 and pH 5 vs. pH 9.5) were identified in the leaves and roots of sugar beet. Several key proteins related to the difference of sugar beet response to acid (pH 5) and alkaline (pH 9.5) and involved in response to acid stress were detected and discussed. Moreover, based on proteomics results, QRT-PCR analysis confirmed that expression levels of three N transporters (NTR1, NRT2.1, and NRT2.5) in roots were relatively high under alkaline conditions (pH 9.5) compared with pH 5 or pH 7.5. The total nitrogen content of pH 9.5 in sugar beet was significantly higher than that of pH 7.5 and pH 5. These studies increase our understanding of the molecular mechanism of sugar beet response to different pH environments.

Physiological and Transcriptome Analysis of Sugar Beet Reveals Different Mechanisms of Response to Neutral Salt and Alkaline Salt Stresses.

The salinization and alkalization of soil are widespread environmental problems. Sugar beet (B. vulgaris L.) is a moderately salt tolerant glycophyte, but little is known about the different mechanisms of sugar beet response to salt and alkaline stresses. The aim of this study was to investigate the influence of neutral salt (NaCl:Na2SO4, 1:1) and alkaline salt (Na2CO3) treatment on physiological and transcriptome changes in sugar beet. We found that a low level of neutral salt (NaCl:Na2SO4; 1:1, Na+ 25 mM) or alkaline salt (Na2CO3, Na+ 25 mM) significantly enhanced total biomass, leaf area and photosynthesis indictors in sugar beet. Under a high concentration of alkaline salt (Na2CO3, Na+ 100 mM), the growth of plants was not significantly affected compared with the control. But a high level of neutral salt (NaCl: Na2SO4; 1:1, Na+ 100 mM) significantly inhibited plant growth and photosynthesis. Furthermore, sugar beet tends to synthesize higher levels of soluble sugar and reducing sugar to cope with high neutral salt stress, and more drastic changes in indole acetic acid (IAA) and abscisic acid (ABA) contents were detected. We used next-generation RNA-Seq technique to analyze transcriptional changes under neutral salt and alkaline salt treatment in sugar beet. Overall, 4,773 and 2,251 differentially expressed genes (DEGs) were identified in leaves and roots, respectively. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that genes involving cutin, suberine and wax biosynthesis, sesquiterpenoid and triterpenoid biosynthesis and flavonoid biosynthesis had simultaneously changed expression under low neutral salt or alkaline salt, so these genes may be related to stimulating sugar beet growth in both low salt treatments. Genes enriched in monoterpenoid biosynthesis, amino acids metabolism and starch and sucrose metabolism were specifically regulated to respond to the high alkaline salt. Meanwhile, compared with high alkaline salt, high neutral salt induced the expression change of genes involved in DNA replication, and decreased the expression of genes participating in cutin, suberine and wax biosynthesis, and linoleic acid metabolism. These results indicate the presence of different mechanisms responsible for sugar beet responses to neutral salt and alkaline salt stresses.

Transcriptome Analysis of Salt-Sensitive and Tolerant Genotypes Reveals Salt-Tolerance Metabolic Pathways in Sugar Beet.

Soil salinization is a common environmental problem that seriously affects the yield and quality of crops. Sugar beet (Beta vulgaris L.), one of the main sugar crops in the world, shows a strong tolerance to salt stress. To decipher the molecular mechanism of sugar beet under salt stress, we conducted transcriptomic analyses of two contrasting sugar beet genotypes. To the best of our knowledge, this is the first comparison of salt-response transcriptomes in sugar beet with contrasting genotypes. Compared to the salt-sensitive cultivar (S710), the salt-tolerant one (T710MU) showed better growth and exhibited a higher chlorophyll content, higher antioxidant enzyme activity, and increased levels of osmotic adjustment molecules. Based on a high-throughput experimental system, 1714 differentially expressed genes were identified in the leaves of the salt-sensitive genotype, and 2912 in the salt-tolerant one. Many of the differentially expressed genes were involved in stress and defense responses, metabolic processes, signal transduction, transport processes, and cell wall synthesis. Moreover, expression patterns of several genes differed between the two cultivars in response to salt stress, and several key pathways involved in determining the salt tolerance of sugar beet, were identified. Our results revealed the mechanism of salt tolerance in sugar beet and provided potential metabolic pathways and gene markers for growing salt-tolerant cultivars.

Effects of Five-Element Music on Language Recovery in Patients with Poststroke Aphasia: A Systematic Review and Meta-Analysis.

Objectives: Five-element music constitutes a complementary therapy in stroke and other acquired brain injuries. Aphasia represents a great problem faced by individuals with stroke. Five-element music, a new type of therapy, may benefit people with poststroke aphasia (PSA). The present study summarized evidences describing the effects of five-element music in language treatment in patients with PSA. Methods: A total of 20 databases and websites were searched from inception to May 2018, including published or unpublished gray literature. Both randomized controlled trials (RCTs) and controlled clinical trials were included in the literature review. Two reviewers independently screened and assessed relevant publications; data extraction was carried out with specific forms. The above reviewers also assessed the quality of each trial by using the Cochrane Handbook for Systematic Reviews of Interventions. After evaluating heterogeneity among studies, quantitative synthesis was applied, where appropriate. Review Manager (Rev Man) 5.3 was employed to examine the pooled effect of five-element music for PSA compared with control therapy. Results: Six RCTs met the eligibility criteria and included 516 patients and were assessed by meta-analysis and quality analysis. Five-element music more significantly increased language scores than Western music therapy or routine care controls in repetition (standardized mean difference [SMD] = 1.96; 95% confidence interval [CI] 0.55-3.37), spontaneous speech (SMD = 1.29; 95% CI 0.53-2.04), and naming (SMD = 1.11; 95% CI 0.80-1.43) (all p < 0.05). No adverse events were reported. Conclusions: Five-element music might moderately improve language rehabilitation in individuals with PSA; however, higher quality RCTs with consistent interventions are required to confirm these findings.

Comparative Physiological and Proteomic Analysis of Two Sugar Beet Genotypes with Contrasting Salt Tolerance.

Soil salinity is one of the major constraints affecting agricultural production and crop yield. A detailed understanding of the underlying physiological and molecular mechanisms of the different genotypic salt tolerance response in crops under salinity is therefore a prerequisite for enhancing this tolerance. In this study, we explored the changes in physiological and proteome profiles of salt-sensitive (S210) and salt-tolerant (T510) sugar beet cultivars in response to salt stress. T510 showed better growth status, higher antioxidant enzymes activities and proline level, less Na accumulation, and lower P levels after salt-stress treatments. With iTRAQ-based comparative proteomics method, 47 and 56 differentially expressed proteins were identified in the roots and leaves of S210, respectively. In T510, 56 and 50 proteins changed significantly in the roots and leaves of T510, respectively. These proteins were found to be involved in multiple aspects of functions such as photosynthesis, metabolism, stress and defense, protein synthesis, and signal transduction. Our proteome results indicated that sensitive and tolerant sugar beet cultivars respond differently to salt stress. The proteins that were mapped to the protein modification, amino acid metabolism, tricarboxylic acid cycle, cell wall synthesis, and reactive oxygen species scavenging changed differently between the sensitive and tolerant cultivars, suggesting that these pathways may promote salt tolerance in the latter. This work leads to a better understanding of the salinity mechanism in sugar beet and provides a list of potential markers for the further engineering of salt tolerance in crops.

Effect of different anesthetic methods on cellular immune functioning and the prognosis of patients with ovarian cancer undergoing oophorectomy.

The present study aimed to explore the effects of different anesthetic methods on cellular immune function and prognosis of patients with ovarian cancer (OC) undergoing oophorectomy. A total of 167 patients who received general anesthesia (GA) treatment (GA group) and 154 patients who received combined general/epidural anesthesia (GEA) treatment (GEA group) were collected retrospectively. Each group selected 124 patients that met the inclusion and exclusion criteria for further study. ELISA and radioimmunoassay were employed to detect levels of IL-2, TNF-α, and CA-125. The rates of tumor-red cell rosette (RTRR), red cell immune complex rosette (RRICR), and red cell C3b receptor rosette (RRCR) were also measured. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were determined by hemodynamics. The levels of tumor necrosis factor-α (TNF-α) and interleukin (IL)-2 decreased at 1 h intraoperation (T2), but increased 24-h post surgery (T3). The levels of TNF-α and IL-2 were recovered faster in the GEA group than in the GA group. The GA group exhibited greater levels of CA-125 expression than in the GEA group. The levels of RTRR, RRICR, and RRCR; ratios of CD3+, CD4+, CD4+/CD8+, CD16+, and CD56+ at 30 min after anesthesia (T1), T2, T3 and 48 h after the operation (T4) and levels of SBP, DBP, and HR at T1, T2, and T3 displayed increased levels in the GEA group than in the GA group. At 72-h post surgery (T5), the 5-year survival rate significantly increased in the GEA group compared with the GA group. GEA to be more suitable than GA for surgery on OC patients.

The physiological and metabolic changes in sugar beet seedlings under different levels of salt stress.

Salinity stress is a major limitation to global crop production. Sugar beet, one of the world's leading sugar crops, has stronger salt tolerant characteristics than other crops. To investigate the response to different levels of salt stress, sugar beet was grown hydroponically under 3 (control), 70, 140, 210 and 280 mM NaCl conditions. We found no differences in dry weight of the aerial part and leaf area between 70 mM NaCl and control conditions, although dry weight of the root and whole plant treated with 70 mM NaCl was lower than control seedlings. As salt concentrations increased, degree of growth arrest became obvious In addition, under salt stress, the highest concentrations of Na+ and Cl- were detected in the tissue of petioles and old leaves. N and K contents in the tissue of leave, petiole and root decreased rapidly with the increase of NaCl concentrations. P content showed an increasing pattern in these tissues. The activities of antioxidant enzymes such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione peroxidase showed increasing patterns with increase in salt concentrations. Moreover, osmoprotectants such as free amino acids and betaine increased in concentration as the external salinity increased. Two organic acids (malate and citrate) involved in tricarboxylic acid (TCA)-cycle exhibited increasing contents under salt stress. Lastly, we found that Rubisco activity was inhibited under salt stress. The activity of NADP-malic enzyme, NADP-malate dehydrogenase and phosphoenolpyruvate carboxylase showed a trend that first increased and then decreased. Their activities were highest with salinity at 140 mM NaCl. Our study has contributed to the understanding of the sugar beet physiological and metabolic response mechanisms under different degrees of salt stress.

Proteomic changes induced by potassium deficiency and potassium substitution by sodium in sugar beet.

In this study, sugar beets (Beta vulgaris L.) were grown at different K(+)/Na(+) concentrations: mmol/L, 3/0 (control); 0.03/2.97 (K-Na replacement group; T(rep)); 0.03/0 (K deficiency group; T(def)) in order to investigate the effects of K(+) deficiency and replacement of K(+) by Na(+) on plant proteomics, and to explore the physiological processes influenced by Na(+) to compensate for a lack of K(+). After 22 days, fresh and dry weight as well as the Na(+) and K(+) concentration were measured and changes in proteomics were tested by 2D gel electrophoresis. Interestingly, Na(+) showed stimulation in growth of seedlings and hindrance of K(+) assimilation in T(rep). Significant changes were also observed in 27 protein spots among the treatments. These are proteins involved in photosynthesis, cellular respiration, protein folding and degradation, stress and defense, other metabolisms, transcription related, and protein synthesis. A wide range of physiological processes, including light reaction, CO2 assimilation, glycolysis, and tricaboxylic acid cycle, was impaired owing to K(+) starvation. Compensating for the effect of K(+) starvation, an increase in photosynthesis was also observed in T(rep). However, we also found a limitation of cellular respiration by Na(+). Na(+) is therefore in some ways able to recover damage due to K deficiency at protein level, but cannot functionally replace K as an essential nutrient.

Transcriptome analysis of Glomus mosseae/Medicago sativa mycorrhiza on atrazine stress.

Arbuscular mycorrhizal fungi (AMF) protect host plants against diverse biotic and abiotic stresses, and promote biodegradation of various contaminants. In this study effect of Glomus mosseae/Medicago sativa mycorrhiza on atrazine degradation was investigated. It was observed that the atrazine degradation rates with any addition level in mycorrhizal treatments were all significantly higher than those in non-mycorrhizal treatments. When atrazine was applied at 20 mg kg(-1), the removal efficiency was up to 74.65%. Therefore, G. mosseae can be considered as ideal inhabitants of technical installations to facilitate phytoremediation. Furthermore, a total of 10.4 Gb was used for de novo transcriptome assembly, resulting in a comprehensive data set for the identification of genes corresponding to atrazine stress in the AM association. After comparative analysis with edgeR, a total of 2,060 differential expressed genes were identified, including 570 up-regulated genes and 1490 down-regulated genes. After excluding 'function unknown' and 'general function predictions only' genes, 172 up-regulated genes were obtained. The differentially expressed genes in AM association with and without atrazine stress were associated with molecular processes/other proteins, zinc finger protein, intracellular/extracellular enzymes, structural proteins, anti-stress/anti-disease protein, electron transport-related protein, and plant growth associated protein. Our results not only prove AMF has important ecological significance on atrazine degradation but also provide evidence for the molecular mechanisms of atrazine degradation by AMF.

Safety assessment of meat from transgenic cattle by 90-day feeding study in rats.

The study was carried out to evaluate the subchronic toxicity of meat derived from human lactoferrin gene-modified cattle in male and female Wistar rats. Rats were fed 5% or 10% transgenic meat diet, 5% or 10% conventional meat diet, or AIN93G diet for 90 days. During the study, body weight and food consumption were weighed weekly and clinical observations were conducted daily. At the end of the study, urinary examination, hematology and blood biochemistry examination, macroscopic and microscopic examinations were performed. There were no biologically significant differences in these factors between the rat groups fed transgenic meat diet and conventional meat diet. Therefore, the present 90-day rodent feeding study suggests that meat derived from the transgenic cattle is equivalent to meat from conventional cattle in use as dietary supplements.

[Isolation, identification and soil remediation of fomesafen-degrading strain FB8].

OBJECTIVE: In order to find new strains to degrade fomesafen in contaminated soil, we isolated and identified a high-efficiency degrading bacterium from polluted soil. The degrading characteristics and remediation ability of the strain were also studied. METHODS: Characteristics of morphological, physiological, biochemical and 16S rRNA sequence were applied to identify the strain. The optimum growth conditions were obtained by studying the effect of environmental factors such as fomesafen concentration, primary pH and temperature on the strain. The strain's remediation ability to fomesafen-polluted soil was verified by sensitive crop and target weeds bioassay in pot soil. RESULTS: A high-efficiency degrading strain FB8 that used fomesafen as sole carbon source was isolated from soybean field suffering fomesafen in Heilongjiang province. It was initially identified as a member of the genus Pseudomonas. The strain could degrade 86.75% of 500 mg/L fomesafen within 96 h. Its optimal growth conditions were determined as follows: 500 mg/L fomesafen, primary pH between 6.0 and 8.0, and at 35 to 37 degrees C. The strain could remedy the sensitive crop maize and sorghum biomass after treating for 30 d for soil contaminated with 5 mg/kg of fomesafen. CONCLUSION: A fomesafen-degrading strain FB8 was selected from fomesafen-contaminated soil in Heilongjiang Province. The strain was closely related to Pseudomonas mendocina. The strain was a suitable candidate for bioremediation of fomesafen-contaminated soil.

Low temperature induced synthesis of TiN nanocrystals.

TiN nanocrystals were successfully prepared through the direct reaction between TiCl(4) and NaNH(2) induced at 300 degrees C. The yield based on Ti is approximately 80%. X-ray powder diffraction indicated that the product was cubic TiN with a lattice constant of a = 4.243 A. Transmission electron microscopy revealed that nanocrystalline TiN with a diameter of 10 nm or so and extremely long straight rods were synthesized. The possible formation mechanism was also proposed.