Quantitative detection of the Ralstonia solanacearum species complex in soil by qPCR combined with a recombinant internal control strain

IMPORTANCE

DNA-based detection and quantification of soil-borne pathogens, such as the Ralstonia solanacearum species complex (RSSC), plays a vital role in risk assessment, but meanwhile, precise quantification is difficult due to the poor purity and yield of the soil DNA retrieved. The internal sample process control (ISPC) strain RsPC we developed solved this problem and significantly improved the accuracy of quantification of RSSC in different soils. ISPC-based quantitative PCR detection is a method especially suitable for the quantitative detection of microbes in complex matrices (such as soil and sludge) containing various PCR inhibitors and for those not easy to lyse (like Gram-positive bacteria, fungi, and thick-wall cells like resting spores). In addition, the use of ISPC strains removes additional workload on the preparation of high-quality template DNA and facilitates the development of high-throughput quantitative detection techniques for soil microbes.

First report of Tobacco Fusarium Root Rot Caused by Fusarium meridionale in China

Tobacco (Nicotiana tabacum L.) was an important economic crop in China. A survey in Yunnan Province in the last several years showed that the incidence of tobacco root rot was 3 to 30%. In July 2021, root rot symptoms were observed with an average incidence of 5% on tobacco (cultivar Yunyan 87) in Dali (25.61° N, 100.27° E). Typical disease symptoms included plants stunted at early stages, brown-colored withering lower leaves and roots that became brown. Under high humidity conditions, symptoms of rot expanded in the roots, also the whole plant became wilted and stunted, and some plants ultimately died. Infected pieces of stem tissues and root were dissected and then sterilized with 2% NaOCl for 30 s, rinsed three times with sterile distilled water, and dried with sterilized filter paper. Three pieces were plated onto potato dextrose agar (PDA) for 3 days at 25°C with a 12-h light period. Colonies on PDA were characterized by white to pale yellow flocculent aerial mycelium, and a pink to red pigment in the agar. To induce sporulation, mycelium on PDA was transferred to carnation leaf agar (CLA) medium. After incubation for 7 days, a single spore was isolated from representative isolate 21DL16 for morphological and molecular analyses. Macroconidia observed on CLA were falcate, slightly curved, three to five septate, measured 33.1 to 53.7 × 3.2 to 4.6 μm (n=50), with a typical foot shaped basal cell. Morphological characteristics of the fungus were in agreement with the description of Fusarium graminearum (Leslie and Summerell 2006). For further identification, the internal transcribed spacer (ITS) region rDNA, translation elongation factor 1ɑ (EF-1α) and RNA polymerase II second largest subunit (RPB2) gene were amplified and sequenced using primers ITS1/ITS4 (White et al. 1990), EF1/EF2 (O'Donnell et al. 2015) and RPB2-5F/RPB2-7cR (Reeb et al. 2004), respectively. Although the ITS sequence (GenBank accession no. OM392025) cannot distinguish F. meridionale from F. graminearum, combined phylogenetic analysis of the sequence of TEF1 (ON062055) and RPB2 (ON211932) clearly showed that the pathogen is F. meridionale that the sequences were 100% similarity, 0.0e-value and 100% query coverage to F. meridionale. Pathogenicity studies were conducted on six-leaf-stage tobacco seedlings cultivar Yunyan 87. A conidial suspension (1×105 spores/mL) was poured over the roots of tobacco seedlings. Three seedlings were treated with sterile water that served as controls. All 10 seedlings were maintained at 25°C at 70% relative humidity. After 5 days, the lower leaves showed symptoms of wilting and the roots of all inoculated seedlings become discolored, that were similar with the original symptoms, whereas the control seedlings did not develop symptoms. The fungus reisolated from the inoculated seedlings was identical to F. meridionale using the EF-1α gene sequence. To date, Fusarium root rot on tobacco in China was caused by F. oxysporium (Chen 2013). However, to the best of our knowledge, this is the first report of F. meridionale causing root rot on tobacco in China. Identification of F. meridionale as a root rot agent might provide important insight for disease management practices on tobacco caused by Fusarium species.

Ralstonia chuxiongensis sp. nov., Ralstonia mojiangensis sp. nov., and Ralstonia soli sp. nov., isolated from tobacco fields, are three novel species in the family Burkholderiaceae

Eight Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacteria were isolated from six tobacco fields in Yunnan, PR China. 16S rRNA gene sequence analysis revealed that all the strains belonged to the genus Ralstonia. Among them, strain 22TCCZM03-6 had an identical 16S rRNA sequence to that of R. wenshanensis 56D2T, and the other strains were closely related to R. pickettii DSM 6297T (98.34–99.86%), R. wenshanensis 56D2T (98.70–99.64%), and R. insidiosa CCUG 46789T (97.34–98.56%). Genome sequencing yielded sizes ranging from 5.17 to 5.72 Mb, with overall G + C contents of 63.3–64.1%. Pairwise genome comparisons showed that strain 22TCCZM03-6 shared average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values above the species cut-off with R. wenshanensis 56D2T, suggesting that strain 22TCCZM03-6 is a special strain of the R. wenshanensis. Five strains, including 21MJYT02-10T, 21LDWP02-16, 22TCJT01-1, 22TCCZM01-4, and 22TCJT01-2, had ANI values >95% and dDDH values >70% when compared with each other. These five strains had ANI values of 73.32–94.17% and dDDH of 22.0–55.20% with the type strains of the genus Ralstonia individually, supporting these five strains as a novel species in the genus Ralstonia. In addition, strains 21YRMH01-3T and 21MJYT02-11T represent two independent species. They both had ANI and dDDH values below the thresholds for species delineation when compared with the type species of the genus Ralstonia. In strains 21YRMH01-3T and 21MJYT02-10T, the main fatty acids were summed features 3, 8, and C16:0; however, strain 21MJYT02-11T contained C16:0, cyclo-C17:0, and summed features 3 as major fatty acids. The main polar lipids, including diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine, were identified from strains 21YRMH01-3T, 21MJYT02-10T, and 21MJYT02-11T. The ubiquinones Q-7 and Q-8 were also detected in these strains, with Q-8 being the predominant quinone. Based on the above data, we propose that the eight strains represent one known species and three novel species in the genus Ralstonia, for which the names Ralstonia chuxiongensis sp. nov., Ralstonia mojiangensis sp. nov., and Ralstonia soli sp. nov. are proposed. The type strains are 21YRMH01-3T (=GDMCC 1.3534T = JCM 35818T), 21MJYT02-10T (=GDMCC 1.3531T = JCM 35816T), and 21MJYT02-11T (=GDMCC 1.3532T = JCM 35817T), respectively.

Ralstonia wenshanensis sp. nov., a novel bacterium isolated from a tobacco field in Yunnan, China

A Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacterium strain (56D2^T) was isolated from tobacco planting soil in Yunnan, PR China. Major fatty acids were C_{16  :  1} ω7c (summed feature 3), C_{16  :  0} and C_{18  :  1}  ω7c (summed feature 8). The polar lipid profile of strain 56D2^T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid and one unidentified glycolipid. Moreover, strain 56D2^T contained ubiquinone Q-8 as the sole respiratory quinone. 16S rRNA gene sequence analysis showed that strain 56D2^T was closely related to members of the genus Ralstonia and the two type strains with the highest sequence identities were R. mannitolilytica LMG 6866^T (98.36 %) and R. pickettii K-288^T (98.22 %). The 16S rRNA gene sequence identities between strain 56D2^T and other members of the genus Ralstonia were below 98.00 %. Genome sequencing revealed a genome size of 5.87 Mb and a G+C content of 63.7 mol%. The average nucleotide identity values between strain 56D2^T and R. pickettii K-288^T, R. mannitolilytica LMG 6866 ^T and R. insidiosa CCUG 46789^T were less than 95 %, and the in silico DNA-DNA hybridization values (yielded by formula 2) were less than 70 %. Based on these data, we conclude that strain 56D2^T represents a novel species of the genus Ralstonia, for which the name Ralstonia wenshanensis sp. nov. is proposed. The type strain of Ralstonia wenshanensis sp. nov. is 56D2^T (=CCTCC AB 2021466^T=GDMCC 1.2886^T=JCM 35178^T).

Pseudomonas lijiangensis sp. nov., a novel phytopathogenic bacterium isolated from black spots of tobacco

Three Gram-stain-negative, motile, with amphilophotrichous flagella, and rod-shaped bacteria (LJ1, LJ2T and LJ3) were isolated from lower leaves with black spots on flue-cured tobacco in Yunnan, PR China. The results of phylogenetic analysis based on 16S rRNA gene sequences indicate that all the strains from tobacco were closely related to the type strains of the Pseudomonas syringae group within the P. fluorescens lineage and LJ2T has the highest sequence identities with P. cichorii DSM 50259T (99.92 %), P. capsici Pc19-1T (99.67 %) and P. ovata F51T (98.94 %) . The 16S rRNA gene sequence identities between LJ2T and other members of the genus Pseudomonas were below 98.50%. The average nucleotide identity by blast (ANIb) values between LJ2T and P. cichorii DSM 50259T, P. capsici Pc19-1T and P. ovata F51T were less than 95 %, and the in silico DNA–DNA hybridization (isDDH) values (yielded by formula 2) were less than 70 %. The major fatty acids were C16  :  1ω7c and/or C16  :  1ω6c (summed feature 3), C16  :  0 and C18  :  1ω7c and/or C18  :  1ω6c (summed feature 8). The polar lipids profile of LJ2T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, two unidentified phospholipids and one unidentified glycolipid. The predominant respiratory quinone was Q-9. The DNA G+C content of LJ2T was 58.4 mol%. On the basis of these data, we concluded that LJ2T represents a novel species of the genus Pseudomonas , for which the name Pseudomonas lijiangensis sp. nov. is proposed. The type strain of Pseudomonas lijiangensis sp. nov. is LJ2T (=CCTCC AB 2021465T=GDMCC 1.2884T=JCM 35177T).

First Report of Pectobacterium versatile Causing Stem Rot of Tobacco in China

Tobacco is one of the most significant non-food cash crops (Lu et al. 2020). In March 2022, cigar tobacco plants showing characteristic symptoms of vascular discoloration, stem rotting, leaf wilting and rotting were observed in Tengchong city (N 25°3'26″, E 98°25'6″) of Yunnan province, China (Fig. S1). The disease incidence was about 5% on cultivar Yunxue 6 in a 33-ha field. Infected stems were collected from Tengchong for pathogen isolation and 16S rDNA sequence analysis was performed as previously described (Lu et al. 2021). Sequence analysis showed that tobacco isolates (GenBank accession numbers: ON795108, ON795107 and ON795106) had an identical sequence with that of the species type strain of Pectobacterium versatile CFBP 6051T and shared the sequence identities of 99.55% and 99.47% with P. carotovorum DSM 30168T and P. parvum s0421T, respectively. Furthermore, phylogenetic analysis showed that tobacco strains were clustered with Pectobacterium versatile CFBP 6051T (Fig. S2a). In API assays, strain 22TC1 was positive for β-galactosidase activity, reduction of nitrates to nitrites, fermentation of glucose, hydrolysis of esculin and gelatin, assimilation of D-glucose, L-arabinose, D-mannose, D-mannitol, N-acetylglucosamine, malic acid and trisodium citrate; positive for the enzymatic substrates of alkaline phosphatase, leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, α-galactosidase, β-galactosidase and α-glucosidase. Furthermore, the average nucleotide identity (ANI) analysis (Richter et al. 2015) showed that strain 22TC1 (GenBank accession number: JAMWYQ000000000) had the highest ANIb score of 96.76% and ANIm value of 97.19% with P. versatile CFBP 6051T. Similarly, in silico DNA-DNA hybridization (isDDH) value was 74.5% compared to P. versatile CFBP 6051T, isDDH values were 35.5-63.7% with the other Pectobacterium species, which below the 70% threshold value for species delineation (Meier-Kolthoff et al. 2021). The phylogenomic analysis also showed that strain 22TC1 was clustered with the species type strain of P. versatile CFBP 6051T. For pathogenicity tests, cell suspension with ten-fold dilution (approx. 1 x 108 CFU/ml) was injected into the leaf axils of two 2-month-old tobacco stems (cv. Yunyan 87). As a control, tobacco seedlings were inoculated with sterile distilled water. The plants were sealed in plastic bags and maintained in a growth chamber at 28°C for 2 d. The symptoms of water-soaked decay were observed within 24 h of inoculation. Whole-plant decay was at 2 days after injection. No symptoms were developed in the controls. Reisolation was performed on diseased stems and the identity of isolated bacteria was confirmed by PCR and sequencing of 16S rRNA. Similar results were obtained in two independent experiments. Based on the above-described data, the causal pathogen of stem rot on cigar tobacco in Tengchong was identified as P. versatile. To our knowledge, this is the first time that P. versatile is found to cause stem rot on tobacco. Pectobacterium species have been reported to cause seed-borne diseases on tobacco seedlings in the floating tray system and soil-borne diseases in tobacco fields (Wang et al. 2017; Xia and Mo 2007). Therefore, studying the possible transmission of the P. versatile to tobacco plants is necessary.

Complete Genome Sequence of Ralstonia syzygii subsp. indonesiensis Strain LLRS-1, Isolated from Wilted Tobacco in China

Here, we present the complete genome sequence and annotation of Ralstonia syzygii subsp. indonesiensis strain LLRS-1, which caused bacterial wilt on flue-cured tobacco in Yunnan Province, southwest China. Strain LLRS-1 is the first R. syzygii strain identified to be pathogenic to tobacco in China. The completely assembled genome of strain LLRS-1 consists of a 3,648,314-bp circular chromosome and a 2,046,405-bp megaplasmid with 5,190 protein-coding genes, 55 transfer RNAs, 28 small RNAs, 3 structural RNAs (5S, 16S, and 23S), and a G+C content of 67.05%.

NtSWEET1 promotes tobacco resistance to Fusarium oxysporum-induced root rot disease

Sugars Will Eventually be Exported Transporter (SWEET) is a newly characterized family of sugar transporters, which plays critical roles in plant-pathogen interactions. However, the function of SWEET in tobacco and its interaction with Fusarium oxysporum, a causal agent of root rot, remain unclear. This study aimed to dissect the function of NtSWEETs in tobacco root rot using stem bases from tobacco plants inoculated with F. oxysporum. RNA-sequencing (RNA-Seq) analysis was performed, and the results indicated that Sucrose Transporter 4 (NtSUC4), Sugar Transporter 12 (NtSTP12), Hexose Transporter 6 (NtHEX6), NtSWEET1, NtSWEET3b, and NtSWEET12 were downregulated by infection with F. oxysporum. The expression of NtSWEET1, but not of NtSUC4, NtSTP12, NtHEX6, NtSWEET3b, or NtSWEET12, was suppressed at all the time points tested after inoculation with F. oxysporum. The NtSWEET1-green fluorescent protein was localized on the plasma membrane and possessed the ability to transport glucose, fructose and galactose. Compared with the wild-type plants, NtSWEET1 RNAi plants were more susceptible to root rot, indicating that NtSWEET1 positively regulated the defense of tobacco against root rot. This study identified the role of SWEETs in tobacco and their interaction with F. oxysporum. The results might be useful in protecting tobacco plants from root rot.

Research Progress on the Determination of Electrical Conductivity in Forensic Science

Abstract

Electrical conductivity （EC） is an important physical and chemical index in electrochemical analysis. In recent years, with the penetration and reference of transformation medicine and interdisciplinary theory and technology in the forensic field, new applications of EC in the field of forensic science have been developed. This paper reviews three aspects of the application of EC, the determination of biological tissue freshness, postmortem interval estimation and the application in forensic taphonomy, in order to provide reference for relevant scientific research and related practices.

Relationship between Electrical Conductivity and Chemical Content of Rat Skeletal Muscle Impregnating Solution and Postmortem Interval

Abstract

Objective To study the mechanism of change of the electrical conductivity （EC） of rat skeletal muscle impregnating solution that occurs with the change of postmortem interval （PMI）. Methods Healthy Sprague-Dawley rats were killed and kept at about 25 ℃. Skeletal muscles were extracted at different PMI--immediate （0 d）, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d, and 7 d, then mixed with deionized water to make impregnating solution with a mass concentration of 0.1 g/mL. The solution's EC and nine common chemicals in it, such as potassium ion, calcium ion, and chloride ion, were determined. Results EC increased gradually with the extending of PMI （P=0.024） during the 7 days after the rats' death. The content of uric acid （P=0.032）, urea nitrogen （P=0.013） and phosphorus （P=0.022） also increased during the extension. However, the content of magnesium ions decreased with extending of PMI （P=0.047）. The correlation between potassium ion, sodium ion, chlorine ion, calcium ion, creatinine and PMI were weak （P>0.05）. Conclusion The molecular basis of skeletal muscle EC change in rats after their death is the changes of uric acid, urea nitrogen, inorganic phosphorus and other chemical components. Furthermore, combine use of various indicators can improve the accuracy of the EC method to infer PMI.

[Reduction of the atlantoaxial dislocation associated with basilar invagination through single-stage posterior approach: using Xuanwu occipital-cervical reduction surgical suite]

Objective: To examine the effect of posterior reduction in atlantoaxial dislocation (AAD) associated with basilar invagination(BI) using Xuanwu occipital-cervical fusion system in single stage. Methods: Thirty-seven AAD accompanied with BI cases treated at Department of Neurosurgery, Xuanwu Hospital, Capital Medical Universiy and the Second Hospital of Hebei Medical University were retrospective analyzed. There were 15 males and 22 females with age of (42.3±12.3)years (range: 18-69 yars). All the cases had congenital osseous abnormalities, such as assimilation of atlas and abnormal cervical fusion. Anterior tissue was released through posterior route followed by cage implantation into facet joint and occipital-cervical fixation with cantilever technique. The clinical results were evaluated using Japanese Orthopedic Association scale(JOA) and the main radiological measurements including anterior atlantodental interval (ADI),the distance of odontoid tip above Chamberlain line,clivus-canal angle (CCA) and the length of syrinx were collected.The preoperative and postoperative JOA score and radiological measurements were compared by paired t-test. Results: The mean JOA score of the patients increased from 10.5 to 14.4 at the one-year follow-up(t=14.3,P=0.00).Complete reduction of AAD and BI was achieved in 34 patients.The mean clivus-canal angle improved from 118.0 degrees preoperative to 143.7 degrees postoperative(t=6.2,P=0.00). Shrinkage of the syrinx was observed 1 week after surgery in 24 patients, and 6 months in 31 patients. Twenty-eight patients achieved bone fusion 6 months after surgery. All the patients achieved bone fusion 12 months after surgery. One-side vertebral artery occlusion was diagnosed in 1 case postoperatively for transient dizziness, and relieved in 2 weeks. Two patients developed moderate neck pain after surgery, and relieved in 1 month. No implant failure, spacer subsidence or infection was observed. Conclusions: The treatment of AAD associated with BI using Xuanwu occipital-cervical fusion system from posterior approach in single stage is effective and safe. Cage implantation intraarticularly and fixation with cantilever technique achieve complete reduction in most cases.

Relationship between Early Postmortem Interval and Electrical Conductivity of Rat Liver, Spleen and Kidney after Death in Rats

OBJECTIVES

To determine the electrical conductivity （EC） of the liver, spleen and kidney of rats at different postmortem intervals （PMIs） within 24 hours for investigating the relationship between EC of different organs and early PMI.

METHODS

Totally 45 SD rats were sacrificed by cervical dislocation and kept at a constant temperature of 25 ℃. Tissues were taken from the liver, spleen, and kidney of rats at 0, 3, 6, 9, 12, 15, 18, 21 and 24 h. Impregnating solution with a mass concentration 0.1 g/mL was prepared using deionized water. The EC value of impregnating solution with different organs was separately determined. The regression equations of EC and PMI for different organs were established, respectively. The relationship between EC of different organs and early PMI was analysed in deceased rats.

RESULTS

The relationship between PMI and EC of the liver and spleen was well fitted with the linear equation. The liver showed the best fitting degree followed by the spleen, while the EC of the kidney showed no significant changes within 24 h. There was a good linear relationship between early PMI and the EC of the liver and spleen.

CONCLUSIONS

A good linear relationship between early PMI and the EC of the liver and spleen can be found in rats after death, which can be used for the early PMI estimation.

[Molecular Identification of Sarcosaphagous Flies in Luoyang Based on 28S rRNA Gene Sequence]

OBJECTIVES

To detect 715 bp sequence of 28S rRNA in sarcosaphagous flies, and to identify their common species for solving the problem of morphological identification, as well as providing technical support for postmortem interval （PMI） estimation.

METHODS

Twenty-nine common sarcosaphagous flies were collected in Luoyang and classified by morphological characteristics. The DNA was extracted from the fly's legs by Chelex-100 method and then the fragments of 28S rRNA were amplified and sequenced. The results were compared with twenty-eight corresponding fly species of GenBank and EMBL databases. All the sequences were analyzed by MEGA7.0 software, and sequence alignment was performed by the searching in BLAST. The nucleotide composition was analysed, and the intraspecific and interspecific genetic distance and phylogenetic tree were established.

RESULTS

Twenty-nine sarcosaphagous flies were classified into 6 species of 5 genera, 3 families by morphological characteristics. In the obtained 715 bp sequence of 28S rRNA, the comparison result of online BLAST showed that the similarity was 100%. Five species were well clustered by a phylogenetic tree. Between different groups, the interspecific and intraspecific differences ranged from 0.007 to 0.045 and 0 to 0.001, respectively.

CONCLUSIONS

The 28S rRNA target gene sequences shows a good identification capability, which can be a new genetic marker for the identification of sarcosaphagous flies.

[Relationship between the Change Rules of Volatile Organic Compounds in Rat Muscle and Postmortem Interval]

OBJECTIVES

To explore the relationship between the change rules of volatile organic compounds （VOCs） in rat muscle and postmortem interval （PMI）.

METHODS

A total of 120 healthy rats were divided randomly into 12 groups （10 for each group）. After the rats were sacrificed by cervical dislocation, the bodies were kept at （25±1） ℃. Rat muscle samples were separately obtained at 12 PMI points, including 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 d. The VOCs in rat muscles were collected, detected and analyzed by headspace solid-phase microextraction （HS-SPME） coupled to gas chromatography-mass spectrometer （GC-MS）.

RESULTS

In total, 15 species of VOCs were identified, including 9 aromatic compounds, 3 sulfur compounds, 2 aliphatic acids and 1 heterocyclic compound. The species of VOCs increased with PMI： no species were detected within 1 day, 3 species were detected on day 2, 9 on day 3, 11 on day 4, 14 from day 5 to 7, and 15 from day 8 to 10. Total peak area of 15 species of VOCs was significantly correlated to PMI （adjusted R²=0.15-0.96）： the regression function was y=-17.05 x²+ 164.36 x-246.36 （adjusted R²=0.96） from day 2 to 5, and y=2.24 x+101.13 （adjusted R²=0.97） from day 6 to 10.

CONCLUSIONS

The change rules of VOCs in rat muscle are helpful for PMI estimation.

[Relationship between Electrical Conductivity and Decomposition Rate of Rat Postmortem Skeletal Muscle]

OBJECTIVES

To analyze the relationship among electrical conductivity （EC）, total volatile basic nitrogen （TVB-N）, which is an index of decomposition rate for meat production, and postmortem interval （PMI）. To explore the feasibility of EC as an index of cadaveric skeletal muscle decomposition rate and lay the foundation for PMI estimation.

METHODS

Healthy Sprague-Dawley rats were sacrificed by cervical vertebrae dislocation and kept at 28 ℃. Muscle of rear limbs was removed at different PMI, homogenized in deionized water and then skeletal extraction liquid of mass concentration 0.1 g/mL was prepared. EC and TVB-N of extraction liquid were separately determined. The correlation between EC (x₁) and TVB-N (x₂) was analyzed, and their regression function was established. The relationship between PMI (y) and these two parameters were studied, and their regression functions were separately established.

RESULTS

The change trends of EC and TVB-N of skeletal extraction liquid at different PMI were almost the same, and there was a linear positive correlation between them. The regression equation was x₂=0.14x₁-164.91(R²=0.982). EC and TVB-N of skeletal muscle changed significantly with PMI, and the regression functions were y=19.38x₁³-370.68x₁²+2 526.03 x₁-717.06(R²=0.994), and y=2.56x₂³-48.39x₂²+330.60x₂-255.04(R²=0.997), respectively.

CONCLUSIONS

EC and TVB-N of rat postmortem skeletal muscle show similar change trends, which can be used as an index for decomposition rate of cadaveric skeletal muscle and provide a method for further study of late PMI estimation.

Biodegradation of the Herbicide 2,4-Dichlorophenoxyacetic Acid by a New Isolated Strain of Achromobacter sp. LZ35

In this study, a bacterial strain of Achromobacter sp. LZ35, which was capable of utilizing 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxy acetic acid (MCPA) as the sole sources of carbon and energy for growth, was isolated from the soil in a disused pesticide factory in Suzhou, China. The optimal 2,4-D degradation by strain LZ35 occurred at 30 °C and pH 8.0 when the initial 2,4-D concentration was 200 mg L^-1. Strain LZ35 harbored the conserved 2,4-D/alpha-ketoglutarate dioxygenase (96%) and 2,4-dichlorophenol hydroxylase (99%), and catabolized 2,4-D via the intermediate 2,4-dichlorophenol. The inoculation of 7.8 × 10⁶ CFU g^-1 soil of strain LZ35 cells to 2,4-D-contaminated soil could efficiently remove over 75 and 90% of 100 and 50 mg L^-1 2,4-D in 12 days and significantly released the phytotoxicity of maize caused by the 2,4-D residue. This is the first report of an Achromobacter sp. strain that was capable of mineralizing both 2,4-D and MCPA. This study provides us a promising candidate for its application in the bioremediation of 2,4-D- or MCPA-contaminated sites.

Study of the expression of GABA(A) receptor in rats during acute lung injury caused by endotoxin

The objective of the present study was to investigate the role of γ-aminobutyric acid type A receptor (GABA(A)R) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats. Thirty-two male wistar rats were randomly divided into four groups. Rats in the GABA group were pretreated with LPS and GABA, while those in the bicuculline (BIC) group were pretreated with LPS and bicuculline. We assessed the arterial blood gas, dry/wet ratio, and the level of tumor necrosis factor-α (TNF-α), IL-6, malondialdehyde, and superoxide dismutase 6 h after the immunization. Paraffin sections of samples were detected using the steptavidin-peroxidase method. Protein expression was detected using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting. PaO2 in the LPS group was significantly lower than that in the control rats. Activation of GABA-mediated signaling by GABA increased the expression of GABA(A)R in airway bronchial and alveolar epithelial cells. Blockade of the GABA(A)R by bicuculline limited the expression of this receptor. The GABA group rats had higher levels of tissue TNF-α and IL-6 than in ALI rats and control rats. The BIC group rats demonstrated an opposite expression level compared to the GABA group rats. Our results suggest that the GABA(A)R could aggravate the inflammatory response syndrome and oxidative stress in the lungs and play an essential role in LPS-induced acute lung injury. It provides a novel method to study the incidence and mortality of ALI during the peroperative period.

Recombinant PTD-Cu/Zn SOD attenuates hypoxia-reoxygenation injury in cardiomyocytes

BACKGROUND

Oxidative stress plays a pivotal role in myocardial ischemia-reperfusion injury. Increasing the protein expression of intracellular Cu/Zn SOD, which is the major endogenous antioxidant enzyme, may attenuate or prevent hypoxia-reoxygenation injury (HRI) in cultured cardiomyocytes. However, ectogenic Cu/Zn-SOD can hardly be transferred into cells to exert biological effects. In this study, we constructed PTD-Cu/Zn SOD plasmid with a kind of translocation structure-Protein transduction domain (PTD) and detected its transmembrane ability and antioxidant effects in H9c2 rat cardiomyocytes subjected to hypoxia/reoxygenation injury (HRI).

METHODS

We constructed the pET-PTD-Cu/Zn SOD (CDs) prokaryotic expression vectors in plasmid that were inserted into E. coli BL21 to induce the protein expression of PTD-Cu/Zn SOD. H9c2 cardiomyocyte HRI was achieved by exposing cardiomyocytes to 12 h hypoxia followed by 2 h reoxygenation. Protein expression of PTD-Cu/Zn SOD in cardiomyocytes was assayed by Western blot and their enzyme activities were investigated by immunohistochemistry and flow cytometry.

RESULTS

In cultured cardiomyocytes hypoxia-reoxygenation injury model, exogenous PTD-Cu/Zn SOD could penetrate cell membrane to clear superoxide anion and decrease hydrogen peroxide level in H9c2 cardiomyocytes subjected to HRI. The level of mitochondrial membrane potential was restored to normal, and the cell apoptosis was reduced in cardiomyocytes with PTD-Cu/Zn SOD treatment during HRI.

CONCLUSION

Recombinant PTD-Cu/Zn SOD could scavenge intracellular-free superoxide anion, protect mitochondria from damages, and attenuate the hypoxia-reoxygenation injury in cultured cardiomyocytes.

Impact of carotid artery stenting on plasma interleukin-6, tumor necrosis factor-α and C-reactive protein

AIM

This study aimed to investigate the impact of carotid artery stenting (CAS) on plasma levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) and C-reactive protein (CRP).

METHODS

The levels of CRP, IL-6, and TNF-α were measured in 61 patients before CAS, 1 h, 2 weeks, 1 month, 6 months, and 12 months after the stenting.

RESULTS

The levels of CRP, IL-6 and TNF-α increased immediately after CAS (P<0.05 or <0.01). The levels of CRP, IL-6 and TNF-α in patients receiving two stents for multiple lesions or single diffusive lesions was also high than in patients receiving one stent for a single lesion (P<0.05 or <0.01). The levels of CRP, IL-6 and TNF-α in patients with restenosis (14/61, or 23%) were higher than in those without restenosis (P<0.05 or <0.01).

CONCLUSION

CAS was associated with a significant increase in plasma CRP, IL-6 and TNF-α. The levels of these inflammatory factors in patients with post-CAS restenosis were higher than in those without restenosis.

[Clinical observation on gastrointestinal protective effect of Composite Salviae injection in patients undergoing cardio-pulmonary bypass heart surgery]

OBJECTIVE

To observe the gastrointestinal protective effect of Composite Salviae Injection (CSI) in patients undergoing cardio-pulmonary bypass (CPB) heart surgery.

METHODS

Eighteen patients, who were scheduled to cardiac surgery (either atrial or ventrical septal repairing) undergoing CPB were randomized equally into two groups. Before CPB, the CSI group was treated with CSI 0.5 ml/kg by intravenous dripping and the control group was treated with normal saline in equal volume. The intragastric mucosa pH value (pHi) of patients was monitored by tensiometer.

RESULTS

As compared with the pre-CPB value, pHi lowered significantly during, 1 h and 2 hrs after CPB in the control group (P < 0.05 or P < 0.01), while in the CSI group, pHi lowered significantly only during CPB (P < 0.05), but with insignificant change at 1 h and 2 hrs after CPB. Comparison between the two groups showed that pHi value in the CSI group was higher significantly than that in the control group at all respective monitoring period (P < 0.05).

CONCLUSION

CSI has gastrointestinal protective effect in patients undergoing CPB cardiosurgery to some extent.

The Shanghai 800: prevalence of tardive dyskinesia in a Chinese psychiatric hospital

The authors found that 73 (8.4%) of 866 patients with chronic schizophrenia in the Shanghai Psychiatric Hospital who had been treated with neuroleptics had tardive dyskinesia. This low prevalence rate is possibly ascribable to the use of relatively low doses of neuroleptics.

Lower CSF level of dynorphin(1-8) immunoreactivity in schizophrenic patients

Using a highly specific and sensitive radioimmunoassay for dynorphin(1-8) (D 1-8), and a singly blind test design, we measured D(1-8) immunoreactivity (ir D 1-8) in CSF of 35 first break cases of acute schizophrenic patients. All patients were free of psychotropic medication for at least one week before the study. Another 31 neurological patients suffered from cervical arthrosis, tumor, myelopathy etc. were studied as controls. The ir D(1-8) in CSF of schizophrenic patients were significantly lower than that of controls (91.8 +/- 5.6, means +/- S.E.M., and 131.9 +/- 6.8 fmol/ml CSF respectively, p less than 0.001).