Maize root exudates promote Bacillus sp. Za detoxification of diphenyl ether herbicides by enhancing colonization and biofilm formation.

Diphenyl ether herbicides are extensively utilized in agricultural systems, but their residues threaten the health of sensitive rotation crops. Functional microbial strains can degrade diphenyl ether herbicides in the rhizosphere of crops, facilitating the restoration of a healthy agricultural environment. However, the interplay between microorganisms and plants in diphenyl ether herbicides degradation remains unclear. Thus, the herbicide-degrading strain Bacillus sp. Za and the sensitive crop, maize, were employed to uncover the interaction mechanism. The degradation of diphenyl ether herbicides by strain Bacillus sp. Za was promoted by root exudates. The strain induced root exudates re-secretion in diphenyl ether herbicide-polluted maize. We further showed that root exudates enhanced the rhizosphere colonization and the biofilm biomass of strain Za, augmenting its capacity to degrade diphenyl ether herbicide. Root exudates regulated gene fliZ, pivotal in biofilm formation. Wild-type strain Za significantly reduced herbicide toxicity to maize compared to the ZaΔfliZ mutant. Moreover, root exudates promoted strain Za growth and chemotaxis, which was related to biofilm formation. This mutualistic relationship between the microorganisms and the plants demonstrates the significance of plant-microbe interactions in shaping diphenyl ether herbicide degradation in rhizosphere soils.

Keguizhuia sedimenti gen. nov., sp. nov., isolated from river sediment represents a novel genus of the family Oxalobacteraceae.

A Gram-stain-negative bacterium, designated as R-40T, was isolated from sediment of the Mulong river in Mianyang city, Sichuan province, PR China. The cells of strain R-40T were aerobic non-motile and formed translucent white colonies on R2A agar. Growth occurred at 15-37 °C (optimum 30 °C), pH 5.0-9.0 (optimum 7.0) and salinities of 0-3.0 % (w/v, optimum 0 %). R-40T showed 95.2-96.6 % 16S rRNA gene sequence similarities with the type strains of species of the genera Oxalicibacterium, Herminiimonas, Lacisediminimonas, Paucimonas, Herbaspirillum and Noviherbaspirillum in the family Oxalobacteraceae. The results of phylogenetic analysis based on genome sequences indicated that the strain was clustered with type strains of species of the genera Oxalicibacterium and Herminiimonas in the family Oxalobacteraceae but formed a distinct lineage. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH) and average amino acid identity (AAI) values between R-40T and type strains of species of the genera Oxalicibacterium, Herminiimonas, Lacisediminimonas, Paucimonas, Herbaspirillum and Noviherbaspirillum ranged from 69.3 to 74.1 %, from 18.2 to 21.4 % and from 60.1 to 67.4 %, respectively. The major cellular fatty acids were C16 : 0, C17 : 0 cyclo and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The major quinone was ubiquinone-8 (Q-8). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phospholipid and small amounts of glycophospholipids. The genome size of R-40T was 5.1 Mbp with 54.0 % DNA G+C content. On the basis of the evidence presented in this study, strain R-40T represents a novel species of a novel genus in the family Oxalobacteraceae, for which the name Keguizhuia sedimenti gen. nov., sp. nov. (type strain R-40T=MCCC 1K08818T=KCTC 8137T) is proposed.

Paenibacillus lacisoli sp. nov., a mesotrione-degrading strain isolated from lakeside soil.

A Gram-stain-positive, facultatively anaerobic, rod-shaped bacterium, designated JX-17T, was isolated from a soil sample collected in Jiangxi Province, PR China. Growth was observed at 15-48 °C (optimum 37 °C), at pH 5.0-9.0 (optimum pH 7.0) and with 0-6.0% (w/v) NaCl (optimum 1.0%). Strain JX-17T could degrade approximately 50% of 50 mg/L mesotrione within 2 days of incubation, but could not use mesotrione as sole carbon source for growth. Strain JX-17T showed less than 95.3% 16S rRNA gene sequence similarity with type strains of the genus Paenibacillus. In the phylogenetic tree based on 16S rRNA gene and genome sequences, strain JX-17T formed a distinct lineage within the genus Paenibacillus. The ANI values between JX-17T and the most closely related type strains P. lentus CMG1240T and P. farraposensis UY79T were 70.1% and 71.4%, respectively, and the dDDH values between them were 19.0% and 23.3%, respectively. The major cellular fatty acids were anteiso-C15:0, iso-C16:0, anteiso-C17:0 and C16:0, the predominant respiratory quinone was MK-7, the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified glycolipid, an aminophospholipid and a phosphatidylinositol. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid, and the DNA G + C content was 50.1 mol%. Based on the phylogenetic, phenotypic and chemotaxonomic characteristics, strain JX-17T represents a novel species within the genus Paenibacillus, for which the name Paenibacillus lacisoli sp. nov is proposed, with strain JX-17T (= GDMCC 1.3962T = KCTC 43568T) as the type strain.

Flavobacterium sedimenticola sp. nov., isolated from sediment.

A novel yellow-pigmented bacterial strain, designated YZ-48T, was isolated from the sediment of the Yangtze River, PR China. Cells were Gram-stain-negative, non-motile, rod-shaped, strictly aerobic, catalase-positive and oxidase-positive. The strain grew optimally on R2A medium at 37 °C, pH 7.0 and with 1.0 % (w/v) NaCl. Strain YZ-48T showed the closest 16S rRNA gene sequence similarity to Flavobacterium solisilvae SE-s27T (96.4 %) and F. dankookense DSM 25687T (96.2 %). The phylogenetic trees based on 16S rRNA gene sequences showed that strain YZ-48T belonged to the genus Flavobacterium but formed a distinct phylogenetic lineage. The obtained average nucleotide identity and digital DNA-DNA hybridization values between YZ-48T and the two closest strains were 75.0 and 74.5 % and 19.6 and 19.0 %, respectively. The sole respiratory quinone was MK-6. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids and three unidentified polar lipids. The major cellular fatty acids were iso-C16 : 0, iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH, iso-C15 : 0 3-OH and iso-C16 : 0 3-OH. The DNA G+C content was 40.2 mol%. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic data, strain YZ-48T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium sedimenticola sp. nov. is proposed, with strain YZ-48T (=KCTC 82329T=CCTC AB 2023061T=MCCC 1K08804T) as the type strain.

Empedobacter sedimenti sp. nov., isolated from sediment of East Taihu Lake.

A Gram-reaction-negative, strictly aerobic, pale yellow, non-gliding, rod-shaped bacterium, designated DT-LB-19T, was isolated from the sediment of East Taihu Lake in Jiangsu Province, PR China. Strain DT-LB-19T showed the highest 16S rRNA gene sequence similarities to members of the genera Algoriella, Chishuiella and Empedobacter (94.84-95.77 %) in the family Weeksellaceae. In phylogenetic trees based on genomes, strain DT-LB-19T clustered within the genus Empedobacter but formed a separate subclade with a high bootstrap value. The average nucleotide identity and digital DNA-DNA hybridization values between DT-LB-19T and the closely related type strains were in the range of 82.5-86.9 % and 25.8-32.3 %, respectively. The major cellular fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, C16 : 1 ω5c, C16 : 0, summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B), summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and iso-C15 : 03-OH. The predominant menaquinone was menaquinone-6. The polar lipid profile consisted of phosphatidylethanolamine, one glycolipid, two aminophospholipids and five unidentified lipids. The DNA G+C content was 31.8 mol%. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic results, we propose that strain DT-LB-19T represents a novel species of the genus Empedobacter, for which the name Empedobacter sedimenti sp. nov. is proposed, with strain DT-LB-19T (=KCTC 82330T=CCTCC AB 2023026T= JSACC 11448T) as the type strain.

Genome analysis of a plasmid-bearing myxobacterim Myxococcus sp. strain MxC21 with salt-tolerant property.

Myxobacteria are widely distributed in various habitats of soil and oceanic sediment. However, it is unclear whether soil-dwelling myxobacteria tolerate a saline environment. In this study, a salt-tolerant myxobacterium Myxococcus sp. strain MxC21 was isolated from forest soil with NaCl tolerance >2% concentration. Under 1% salt-contained condition, strain MxC21 could kill and consume bacteria prey and exhibited complex social behaviors such as S-motility, biofilm, and fruiting body formation but adopted an asocial living pattern with the presence of 1.5% NaCl. To investigate the genomic basis of stress tolerance, the complete genome of MxC21 was sequenced and analyzed. Strain MxC21 consists of a circular chromosome with a total length of 9.13 Mbp and a circular plasmid of 64.3 kb. Comparative genomic analysis revealed that the genomes of strain MxC21 and M. xanthus DK1622 share high genome synteny, while no endogenous plasmid was found in DK1622. Further analysis showed that approximately 21% of its coding genes from the genome of strain MxC21 are predominantly associated with signal transduction, transcriptional regulation, and protein folding involved in diverse niche adaptation such as salt tolerance, which enables social behavior such as gliding motility, sporulation, and predation. Meantime, a high number of genes are also found to be involved in defense against oxidative stress and production of antimicrobial compounds. All of these functional genes may be responsible for the potential salt-toleration. Otherwise, strain MxC21 is the second reported myxobacteria containing indigenous plasmid, while only a small proportion of genes was specific to the circular plasmid of strain MxC21, and most of them were annotated as hypothetical proteins, which may have a direct relationship with the habitat adaptation of strain MxC21 under saline environment. This study provides an inspiration of the adaptive evolution of salt-tolerant myxobacterium and facilitates a potential application in the improvement of saline soil in future.

Structural and Functional Properties of Porous Corn Starch Obtained by Treating Raw Starch with AmyM.

Porous starch is attracting considerable attention for its high surface area and shielding ability, properties which are useful in many food applications. In this study, native corn starch with 15, 25, and 45% degrees of hydrolysis (DH-15, DH-25, and DH-45) were prepared using a special raw starch-digesting amylase, AmyM, and their structural and functional properties were evaluated. DH-15, DH-25, and DH-45 exhibited porous surface morphologies, diverse pore size distributions and pore areas, and their adsorptive capacities were significantly enhanced by improved molecular interactions. Structural measures showed that the relative crystallinity decreased as the DH increased, while the depolymerization of starch double helix chains promoted interactions involving disordered chains, followed by chain rearrangement and the formation of sub-microcrystalline structures. In addition, DH-15, DH-25, and DH-45 displayed lower hydrolysis rates, and DH-45 showed a decreased C∞ value of 18.9% with higher resistant starch (RS) content and lower glucose release. Our results indicate that AmyM-mediated hydrolysis is an efficient pathway for the preparation of porous starches with different functionalities which can be used for a range of applications.

Remediation of fomesafen contaminated soil by Bacillus sp. Za: Degradation pathway, community structure and bioenhanced remediation.

Fomesafen is a diphenyl ether herbicide used to control the growth of broadleaf weeds in bean fields. The persistence, phytotoxicity, and negative impact on crop rotation associated with this herbicide have led to an increasing concern about the buildup of fomesafen residues in agricultural soils. The exigent matter of treatment and remediation of soils contaminated with fomesafen has surfaced. Nevertheless, the degradation pathway of fomesafen in soil remains nebulous. In this study, Bacillus sp. Za was utilized to degrade fomesafen residues in black and yellow brown soils. Fomesafen's degradation rate by strain Za in black soil reached 74.4%, and in yellow brown soil was 69.2% within 30 days. Twelve intermediate metabolites of fomesafen were identified in different soils, with nine metabolites present in black soil and eight found in yellow brown soil. Subsequently, the degradation pathway of fomesafen within these two soils was inferred. The dynamic change process of soil bacterial community structure in the degradation of fomesafen by strain Za was analyzed. The results showed that strain Za potentially facilitate the restoration of bacterial community diversity and richness in soil samples treated with fomesafen, and there were significant differences in species composition at phylum and genus levels between these two soils. However, both soils shared a dominant phylum and genus, Actinobacteriota, Proteoobacteria, Firmicutes and Chloroflexi dominated in two soils, with a high relative abundance of Sphingomonas and Bacillus. Moreover, an intermediate metabolite acetaminophen degrading bacterium, designated as Pseudomonas sp. YXA-1, was isolated from yellow brown soil. When strain YXA-1 was employed in tandem with strain Za to remediate fomesafen contaminated soil, the degradation rate of fomesafen markedly increased. Overall, this study furnishes crucial insights into the degradation pathway of fomesafen in soil, and presents bacterial strain resources potentially beneficial for soil remediation in circumstances of fomesafen contamination.

Quality Characteristics of Reduced-Fat Emulsified Sausages Made with Yeast Mannoprotein Enzymatically Prepared with a ß-1,6-glucanase.

Mannoproteins, as yeast polysaccharides, have been utilized in food the industry as dietary fibers, emulsifying agents or fat replacers. Mannoprotein MP112, produced from yeast by enzymatic hydrolysis of myxobacterial ß-1,6-glucanase GluM, exhibits excellent emulsifying properties in emulsion preparation. In this study, we aimed to examine the application of stable emulsion with the addition of mannoprotein MP112 (MP112 emulsion) to reduce the fat content of sausages. The addition of MP112 emulsion in emulsified sausages significantly reduced the fat content and increased the moisture and protein contents of emulsified sausages without the expense of their good sensory quality. Moreover, the textural properties of sausages were markedly improved with the higher hardness, chewiness and cohesiveness, especially in the 50-75% replacement ratio of MP112 emulsion. On the other hand, MP112 emulsion replacement of animal fat markedly improved the nutritional composition of emulsified sausages; they displayed a higher PUFA/SFA ratio and lower n-6/n-3 ratio due to their saturated fatty acids being replaced by poly-unsaturated fatty acids. Meanwhile, the oxidative stability of sausages was improved linearly, corresponding to the increased replacement ratio of MP112 emulsion. Our results show that mannoprotein-based emulsions could be used as potential fat alternatives in developing reduced-fat meat products.

Development of solid agents of the diphenyl ether herbicide degrading bacterium Bacillus sp. Za based on a mixed organic fertilizer carrier.

The long-term and widespread use of diphenyl ether herbicides has caused serious soil residue problems and threatens the agricultural ecological environment. The development of biodegrading agents using high-efficiency degrading strains as pesticide residue remediation materials has been widely recognized. In this study, the strain Bacillus sp. Za was used to prepare solid agents for the remediation of diphenyl ether herbicides-contaminated soil. The ratio of organic fertilizer was 1:3 (pig manure: cow dung), the inoculum amount of Za was 10%, the application amount of solid agents was 7%, and the application mode was mixed application, all of which were the most suitable conditions for solid agents. After the solid agents were stored for 120 days, the amount of Za remained above 108 CFU/g. The degradation rates of the solid agents for lactofen, bifenox, fluoroglycofen, and fomesafen in soil reached 87.40, 82.40, 78.20, and 65.20%, respectively, on the 7th day. The application of solid agents alleviated the toxic effect of lactofen residues on maize seedlings. A confocal laser scanning microscope (CLSM) was used to observe the colonization of Za-gfp on the surface of maize roots treated in the solid agents, and Za-gfp mainly colonized the elongation zone and the mature area of maize root tips, and the colonization time exceeded 21 days. High-throughput sequencing analysis of soil community structural changes in CK, J (solid agents), Y (lactofen), and JY (solid agents + lactofen) groups showed that the addition of solid agents could restore the bacterial community structure in the rhizosphere soil of maize seedlings. The development of solid agents can facilitate the remediation of soil contaminated with diphenyl ether herbicide residues and improve the technical level of the microbial degradation of pesticide residues.

A Novel Module Promotes Horizontal Gene Transfer in Azorhizobium caulinodans ORS571.

Azorhizobium caulinodans ORS571 contains an 87.6 kb integrative and conjugative element (ICEAc) that conjugatively transfers symbiosis genes to other rhizobia. Many hypothetical redundant gene fragments (rgfs) are abundant in ICEAc, but their potential function in horizontal gene transfer (HGT) is unknown. Molecular biological methods were employed to delete hypothetical rgfs, expecting to acquire a minimal ICEAc and consider non-functional rgfs as editable regions for inserting genes related to new symbiotic functions. We determined the significance of rgf4 in HGT and identified the physiological function of genes designated rihF1a (AZC_3879), rihF1b (AZC_RS26200), and rihR (AZC_3881). In-frame deletion and complementation assays revealed that rihF1a and rihF1b work as a unit (rihF1) that positively affects HGT frequency. The EMSA assay and lacZ-based reporter system showed that the XRE-family protein RihR is not a regulator of rihF1 but promotes the expression of the integrase (intC) that has been reported to be upregulated by the LysR-family protein, AhaR, through sensing host's flavonoid. Overall, a conservative module containing rihF1 and rihR was characterized, eliminating the size of ICEAc by 18.5%. We propose the feasibility of constructing a minimal ICEAc element to facilitate the exchange of new genetic components essential for symbiosis or other metabolic functions between soil bacteria.

Predicting the Postmortem Interval Based on Gravesoil Microbiome Data and a Random Forest Model.

The estimation of a postmortem interval (PMI) is particularly important for forensic investigations. The aim of this study was to assess the succession of bacterial communities associated with the decomposition of mouse cadavers and determine the most important biomarker taxa for estimating PMIs. High-throughput sequencing was used to investigate the bacterial communities of gravesoil samples with different PMIs, and a random forest model was used to identify biomarker taxa. Redundancy analysis was used to determine the significance of environmental factors that were related to bacterial communities. Our data showed that the relative abundance of Proteobacteria, Bacteroidetes and Firmicutes showed an increasing trend during decomposition, but that of Acidobacteria, Actinobacteria and Chloroflexi decreased. At the genus level, Pseudomonas was the most abundant bacterial group, showing a trend similar to that of Proteobacteria. Soil temperature, total nitrogen, NH4+-N and NO3--N levels were significantly related to the relative abundance of bacterial communities. Random forest models could predict PMIs with a mean absolute error of 1.27 days within 36 days of decomposition and identified 18 important biomarker taxa, such as Sphingobacterium, Solirubrobacter and Pseudomonas. Our results highlighted that microbiome data combined with machine learning algorithms could provide accurate models for predicting PMIs in forensic science and provide a better understanding of decomposition processes.

Correlation between sarcopenia and nailfold microcirculation, serum 25-hydroxycholecalciferol (vitamin D3) and IL-17 levels in female patients with rheumatoid arthritis.

AIMS: To investigate the correlation between sarcopenia and nailfold microcirculation and serum 25-hydroxycholecalciferol [25 (OH) D3] (instead of 25-hydroxyvitamin D) and IL-17 levels in female rheumatoid arthritis (RA) patients. METHODS: 130 female rheumatoid arthritis (RA) patients and 80 healthy controls were tested. Nailfold capillaroscopic scores (NFCS) were measured. Bioimpedance analysis (BIA) was used to measure skeletal muscle mass. Enzyme-linked immunosorbant assay (ELISA) was used to detect the levels of IL-17, IL-6 and TNF-α. Serum 25 (OH) D3 concentration was determined by photochemical immunoassay. The correlation was analyzed by Pearson's correlation, and the influencing factors were analyzed by binary logistic regression. RESULTS: (1) Compared with the control group, NFCS and serum IL-17 levels were higher in the RA group, while the serum 25 (OH) D3 and skeletal mass index (SMI) were lower. (2) Pearson correlation analysis found: SMI was positively correlated with 25 (OH) D3 (r=0.515, P<0.001), SMI was negatively correlated with IL-17 (r=-0.468, P<0.001), SMI was negatively correlated with NFS (r = -0.229, P=0.009); (3) Logistic regression analysis: serum 25 (OH) D3 was a protective factor for sarcopenia (OR=0.392, P=0.016); IL-17, C-reactive protein, and NFS were risk factors for sarcopenia (OR=1.516, P=0.049; OR=1.469, P=0.045; OR=3.497, P=0.002). CONCLUSION: Secondary sarcopenia in RA is common and is closely related to microcirculation abnormalities. Increased NFCS is a risk factor for sarcopenia. Decreased serum 25 (OH) D3 levels and increased IL-17 are also risk factors for sarcopenia, but the mechanisms involved in sarcopenia and microcirculation abnormalities need further investigation.

Bilobalide alleviates IL-17-induced inflammatory injury in ATDC5 cells by downregulation of microRNA-125a.

Ankylosing spondylitis (AS) is a high disability and greatly destructive disease. In this study, we preliminarily studied the function and mechanism of bilobalide (BIL) on interleukin (IL)-17-induced inflammatory injury in ATDC5 cells. CCK-8 and migration assays were used to detect the functions of IL-7, BIL, and microRNA (miR)-125a on cell viability and migration. The miR-125a level was changed by transfection, and tested by real-time quantitative polymerase chain reaction. Additionally, Western blot tested the levels of inflammatory factors (IL-6 and tumor necrosis factor-α), matrix metalloproteinases (MMPs), and pathway-related proteins. Moreover, the enzyme-linked immunosorbent assay also was used to detect inflammatory factor levels. IL-7 was used to construct an inflammatory injury model in ATDC5 cells. Based on this, BIL inhibited IL-17-induced cell viability, migration, and expressions of inflammatory factors and MMPs. Furthermore, we found BIL negatively regulated miR-125a, and the miR-125a mimic could partly reverse the effects of BIL on IL-17-injury. Finally, we showed that BIL inhibited the c-Jun N-terminal kinase (JNK) and nuclear factor kappa B (NF-κB) pathways, and the miR-125a mimic had the opposite effect. BIL inhibited IL-17-induced inflammatory injury in ATDC5 cells by downregulation of miR-125a via JNK and NF-κB signaling pathways.

Sinomonas susongensis sp. nov., isolated from the surface of weathered biotite.

A novel actinomycete, designated strain A31(T), was isolated from the surface of weathered biotite in Susong, Anhui Province, China. The organism grew optimally at 30 °C, at pH 8.0 and with 1% (w/v) NaCl. Strain A31(T) had A3α as the cell-wall peptidoglycan type and galactose, mannose and rhamnose as whole-cell sugars. Anteiso-C(15 : 0) and anteiso-C(17 : 0) were the major cellular fatty acids and MK-9(H2) was the predominant respiratory quinone. In addition, the total polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylmonomethylethanolamine and four glycolipids. The genomic DNA G+C content of strain A31(T) was 70.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain A31(T) was related most closely to Sinomonas albida LC13(T) (98.3% similarity), Sinomonas atrocyanea DSM 20127(T) (98.2%), Sinomonas soli CW 59(T) (98.1%), Sinomonas flava CW 108(T) (97.8%), 'Sinomonas mesophila' MPKL 26 (97.3%), Sinomonas echigonensis LC10(T) (97.1%) and ' Sinomonas notoginsengisoli ' SYP-B575 (96.7%). DNA-DNA hybridization studies with the new isolate showed relatedness values of 16.0-56.6% with its six closest neighbours. Based on phenotypic, chemotaxonomic and phylogenetic analysis, strain A31(T) represents a novel species of the genus Sinomonas , for which the name Sinomonas susongensis sp. nov. is proposed. The type strain is A31(T) ( = DSM 28245(T) = CCTCC AB 2014068(T)).

An essential esterase (BroH) for the mineralization of bromoxynil octanoate by a natural consortium of Sphingopyxis sp. strain OB-3 and Comamonas sp. strain 7D-2.

A natural consortium of two bacterial strains ( Sphingopyxis sp. OB-3 and Comamonas sp. 7D-2) was capable of utilizing bromoxynil octanoate as the sole source of carbon for its growth. Strain OB-3 was able to convert bromoxynil octanoate to bromoxynil but could not use the eight-carbon side chain as its sole carbon source. Strain 7D-2 could not degrade bromoxynil octanoate, although it was able to mineralize bromoxynil. An esterase (BroH) that is involved in the conversion of bromoxynil octanoate into bromoxynil and is essential for the mineralization of bromoxynil octanoate by the consortium was isolated from strain OB-3 and molecularly characterized. BroH encodes 304 amino acids and resembles α/ß-hydrolase fold proteins. Recombinant BroH was overexpressed in Escherichia coli BL21 (DE3) and purified by Ni-NTA affinity chromatography. BroH was able to transform p-nitrophenyl esters (C2-C14) and showed the highest activity toward p-nitrophenyl caproate (C6) on the basis of the catalytic efficiency value (Vmax/Km). Additionally, BroH activity decreased when the aliphatic chain length increased. The optimal temperature and pH for BroH activity was found to be 35 °C and 7.5, respectively. On the basis of a phylogenetic analysis, BroH belongs to subfamily V of bacterial lipolytic enzymes.

[Comparison study between main influencing factors and diurnal variation of net photosynthetic rate in different types of Pueraria thomsonii].

OBJECTIVE: To study the diurnal variation of net photosynthetic rate (P(n)) and main influencing factors in different types of Pueraria thomsonii, aimed at providing the theoretical basis for breeding the fine varieties of P. thomsonii suitable for the local light condition. METHOD: Diurnal variations of photosynthesis in leaves of different types of P. thomsonii were determined with the Li-6400 Portable Photosynthesis System. RESULT: (1) Diurnal variation of P(n), transpiration Rate (T(r)), stomatal conductance (G(s)) in leaves of six varieties of P. thomsonii showed unimodal curve and asymmetric bimodal curve. Diurnal variation of water use efficiency (WUE), intercellular CO2 concentration (C(i)) showed single valley curve. Diurnal variation curve of stomatal limitation value (L(s)) was single peak and S-type. (2) P(n) in leaves of six varieties of P. thomsonii was positively correlated with photosynthetic active radiation (PAR), air temperature (T(a)), G(s), and negatively correlated with air relative humidity (RH), C(i), P(n) of all varieties were very significantly correlated with PAR, G(s). CONCLUSION: Diurnal variations of photosynthesis in leaves of different types of P. thomsonii show significant difference. Jiuding, Chuanyu, Gange, Dijin No. 1 planted in Ya'an overcome "midday depression" phenomenon. Hechuan has the greatest photosynthetic potential, suitable for planting in forest understory and intercropping with high stalk to avoid the strong flashes. Planted in long-day region was beneficial to its growth. CO2 use efficiency of Geboshi No. 11 and Dijin No. 1 were significantly higher than that of the others. The accumulation efficiency of organics can be increased in cultivation management by fertilizing CO2.