Filamentous morphology engineering of bacteria by iron metabolism modulation through MagR expression.

The morphology is the consequence of evolution and adaptation. Escherichia coli is rod-shaped bacillus with regular dimension of about 1.5 µm long and 0.5 µm wide. Many shape-related genes have been identified and used in morphology engineering of this bacteria. However, little is known about if specific metabolism and metal irons could modulate bacteria morphology. Here in this study, we discovered filamentous shape change of E. coli cells overexpressing pigeon MagR, a putative magnetoreceptor and extremely conserved iron-sulfur protein. Comparative transcriptomic analysis strongly suggested that the iron metabolism change and iron accumulation due to the overproduction of MagR was the key to the morphological change. This model was further validated, and filamentous morphological change was also achieved by supplement E. coli cells with iron in culture medium or by increase the iron uptake genes such as entB and fepA. Our study extended our understanding of morphology regulation of bacteria, and may also serves as a prototype of morphology engineering by modulating the iron metabolism.

A preliminary investigation of the regulatory effect of acupuncture on hippocampal circHDAC2/miR-3065/SLC30A3 axis in CIRI rats. / å¤§é¼ æµ·é©¬ç»„ç»‡circHDAC2/miR-3065/SLC30A3è½´å‚ä¸Žé’ˆåˆºè°ƒèŠ‚è„‘ç¼ºè¡€å†çŒæ³¨æŸä¼¤çš„åˆæ­¥ç ”ç©¶.

OBJECTIVES: To explore the mechanisms of acupuncture against cerebral ischemia/reperfusion injury (CIRI) through observing the expression of circular RNA HDAC2 (circHDAC2) in the hippocampus of rats. METHODS: SD rats were randomly divided into sham-operation, model and acupuncture groups, with 13 rats in each group. The rat model of CIRI was established by middle cerebral artery occlusion. In the acupuncture group, acupuncture was delivvered at "Dazhui" (GV14), "Shuigou" (GV26) and "Baihui" (GV20), and the needles were retained for 30 min each time and acupuncture was conducted once every 12 h for a total of 7 sessions. Before and after intervention, using modified Garcia scale, the neurological function of the rats were evaluated, and TTC staining was employed to determine the cerebral infarct area. Gene chip technology was used to screen the circRNAs with differential expressions in the ischemic hippocampus, and the circRNAs with co-differential expression (co-DE circRNAs) in the model group/sham-operation group, and the acupuncture group/model group separately. Among those circRNAs, the core circRNAs were screened according to P value, fold change (FC) and gene ontology (GO) analysis；and their expressions in the ischemic hippocampus were determined using quantitative real-time PCR (qPCR). Based on the verification results, a competing endogenous RNA (ceRNA) prediction network was constructed. The expression levels of microRNA (miRNA) and mRNA with high node centrality in the prediction network were validated by qPCR. RESULTS: Before intervention, compared with the sham-operation group, the modified Garcia score of each modeling group decreased (P<0.01). After intervention, the modified Garcia score was reduced and the cerebral infarct area ratio increased (P<0.01) in the model group when compared with the sham-operation group. In the acupuncture group, the modified Garcia score was higher and the cerebral infarct area ratio lower (P<0.01) than those of the model group. The microarray results of gene chip showed that 16 co-DE circRNAs were down-regulated in the model group and up-regulated in the acupuncture group, and 7 co-DE circRNAs up-regulated in the model group and down-regulated in the acupuncture group. The core circHDAC2 and circNTRK2 were screened according to P value, FC and the enrichment number of GO entries. QPCR results showed that, compared with the sham-operation group, the expression of circHDAC2 and circNTRK2 of the ischemic hippocampal tissue was down-regulated in the model group (P<0.01)；and that of circHDAC2 and circNTRK2 up-regulated in the acupuncture group when compared with the model group (P<0.01). The relevant ceRNA regulatory network was constructed for circHDAC2 and the prediction results showed that the regulatory networks contained 12 miRNAs and 31 mRNAs. Results of verifying miRNA with high network node centrality and mRNA relevant with nerve regulation showed that, when compared with the sham-operation group, the expression levels of miR-29a, miR-29b and the solute carrier family 30 member 3 (SLC30A3) mRNA in the ischemic hippocampus were down-regulated (P<0.01)；and those of miR-3065 and mercaptopyruvate sulfurtransferase (MPST) up-regulated (P<0.01) in the model group. Compared with the model group, the expressions of miR-29a, miR-29b and SLC30A3 mRNA in the ischemic hippocampus were up-regulated (P<0.01, P<0.05), while that of miR-3065 down-regulated (P<0.05) in the acupuncture group. CONCLUSIONS: Acupuncture significantly improves the neurological function and reduces the cerebral infarct area in CIRI rats, which may be related to the regulation of hippocampal circHDAC2/miR-3065/SLC30A3 axis.

[Prediction and analysis of Q-markers of Elephantopus scaber based on its UPLC fingerprint, content determination of components, and in vitro a nti-tumor activity].

This study aimed to provide scientific evidence for predicting quality markers(Q-markers) of Elephantopus scaber by establishing UPLC fingerprint of E. scaber from different geographical origins and determining the content of 13 major components, as well as conducting in vitro anti-cancer activity investigation of the main components. The chromatographic column used was Waters CORTECS UPLC C_(18)(2.1 mm×150 mm, 1.6 µm), and the mobile phase consisted of acetonitrile and 0.1% formic acid solution(gradient elution). The column temperature was set at 30 ℃, and the flow rate was 0.2 mL·min~(-1). The injection volume was 1 µL, and the detection wavelength was 240 nm. The UPLC fingerprint of E. scaber was fitted using the Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine(2012 edition) to determine common peaks, evaluate similarity, identify and determine the content of major components. The CCK-8 assay was used to explore the inhibitory effect of the main components on the proliferation of lung cancer cells. The results showed that in the established UPLC fingerprint of E. scaber, 35 common peaks were identified. Thirteen major components, including neochlorogenic acid(peak 1), chlorogenic acid(peak 2), cryptochlorogenic acid(peak 3), caffeic acid(peak 4), schaftoside(peak 6), galuteolin(peak 9), isochlorogenic acid B(peak 10), isochlorogenic acid A(peak 12), isochlorogenic acid C(peak 18), deoxyelephantopin(peak 28), isodeoxyelephantopin(peak 29), isoscabertopin(peak 31), and scabertopin(peak 32) were identified and quantified, and a quantitative analysis method was established. The results of the in vitro anti-cancer activity study showed that deoxyelephantopin, isodeoxyelephantopin, isoscabertopin, and scabertopin in E. scaber exhibited inhibition rates of lung cancer cell proliferation exceeding 80% at a concentration of 10 µmol·L~(-1), higher than the positive drug paclitaxel. These results indicate that the fingerprint of E. scaber is highly characteristic, and the quantitative analysis method is accurate and stable, providing references for the research on quality standards of E. scaber. Four sesquiterpene lactones in E. scaber show significant anti-cancer activity and can serve as Q-markers for E. scaber.

High-fidelity fluorescent probes for visualizing the inhibitory behavior of selenium on cadmium uptake in rice.

Cadmium (Cd), a widespread and highly toxic environmental contaminant, has seriously impacted the growth of rice and the quality of its products. Hence, it is crucial to monitor and employ robust means to reduce Cd levels in rice, and selenium (Se) has been proven to chelate cadmium ion (Cd2+) in rice with rational use. Herein, for the first time, the reported selenocysteine (Sec) probe NN-Sec and the newly designed Cd2+ probe SCP were chosen as visualization tools to monitor Sec-inhibited Cd2+ uptake in rice. Specifically, reduced fluorescence of rice precultured with Cd2+ was observed by SCP after Se application, while similarly decreased fluorescence of rice pretreated with Se was observed by NN-Sec after Cd2+ addition. The diminished fluorescence indicated the formation of Cd-Se complexes reduced the Cd2+ content in rice. Additionally, it was Cd2+ and Se that entered the rice causing the fluorescence generation, as demonstrated by inductively coupled plasma mass spectrometry (ICP-MS). To conclude, the two probes successfully visualized Se inhibited Cd2+ uptake in rice, which could provide a robust tool for supporting the development of novel organic fertilizers and reagents to reduce Cd2+ content in rice and the environment.

Combined apatite, biochar, and organic fertilizer application for heavy metal co-contaminated soil remediation reduces heavy metal transport and alters soil microbial community structure.

Soil amendments are used extensively to remediate soils contaminated with heavy metals. However, the effects of soil amendments on heavy metal bioavailability, plant yield, and bacterial community structure in tropical farmland soils remain largely unknown. In the present study, seaweed organic fertilizer (S), apatite (A), biochar (B), and seaweed organic fertilizer-apatite-biochar mixtures (SAB) were applied at different rates to assess their influence on cadmium (Cd), lead (Pb), and chromium (Cr) bioavailability in contaminated farmland soils, using different component ratios and doses in maize field plots, and maize yield. Effects on soil bacterial community structure were also evaluated based on high-throughput sequencing. Following addition of 2 % S + A + B combined amendment at a ratio of 1:0.5:1.5 (2%S1A0.5B1.5), soil pH and electrical conductivity (EC) were elevated, and bioavailable Cd, Pb, and Cr concentrations were reduced in potted soils, leading to higher heavy metal immobilization. Under field conditions, soil pH, EC, organic matter, ammonium­nitrogen, available phosphorus, available potassium, and crop productivity were all increased considerably, whereas soil Cd and Cr bioavailability were lower in the combined amendment treatments than in the control treatments. Particularly, application of a 2.49 t·ha-1 combined amendment (0.83 t·ha-1 S + 0.41 t·ha-1A + 1.25 t·ha-1B,1:0.5:1.5) decreased Cd, Pb, and Cr concentrations in maize grain by 68.9 %, 68.9 %, and 65.7 %, respectively. Species abundance and evenness in bacterial communities increased in field soils subjected to combined amendments, with shifts in community structure and function mostly driven by changes in soil pH, organic matter content, and nutrient availability. Overall, the results suggest that 1.5%S1A0.5B1.5 is the optimal treatment for remediating heavy metal co-contaminated soil, and thereby, improving maize yield and quality. Combined organic and inorganic amendments achieve high remediation efficiency, mainly by improving chemical properties, reducing heavy metal bioavailability, and altering bacterial community structure and function in heavy metal contaminated farmland soils.

A Rationally Designed Building Block of the Putative Magnetoreceptor MagR.

The ability of animals to perceive guidance cues from Earth's magnetic field for orientation and navigation has been supported by a wealth of behavioral experiments, yet the nature of this sensory modality remains fascinatingly unresolved and wide open for discovery. MagR has been proposed as a putative magnetoreceptor based on its intrinsic magnetism and its complexation with a previously suggested key protein in magnetosensing, cryptochrome, to form a rod-like polymer structure. Here, we report a rationally designed single-chain tetramer of MagR (SctMagR), serving as the building block of the hierarchical assembly of MagR polymer. The magnetic trapping experiment and direct magnetic measurement of SctMagR demonstrated the possibility of magnetization of nonmagnetic cells via overexpressing a single protein, which has great potential in various applications. SctMagR, as reported in this study, serves as a prototype of designed magnetic biomaterials inspired by animal magnetoreception. The features of SctMagR provide insights into the unresolved origin of the intrinsic magnetic moment, which is of considerable interest in both biology and physics. © 2022 Bioelectromagnetics Society.

[Clinical study of teicoplanin in the treatment of patients with gram-positive cocci: the Chinese experience].

OBJECTIVE: To evaluate the efficacy and safety of Teicoplanin (TEC) in the treatment of Chinese patients with moderate and severe Gram positive (G(+)) coccus infections. METHODS: A prospective, multicenter, non-comparator control, open-label drug clinical trial of phase IV was conducted. RESULTS: Totally 156 cases with established and highly suspected G(+) coccus infections are enrolled. Mean age was 53.6 +/- 20.9 (9-93). The infections included: lower respiratory tract infections (66.0%), sepsis (9.0%), catheters-associated infections (5.1%), endocarditis (1.9%), leucopenia with fever (14.1%), bone-joint infections (1.3%), skin-soft tissue infections (7.7%), and other infections (10.9%). Eighty seven point eight percent of the patients suffered from severe underlying diseases, 28.2% (44/156) had immunocompromised conditions. 69.2% had received antibiotics previously (57.4% with cephalosporins and 28.7% with carbapenem, respectively). One hundred and thirty strains of G(+) cocci were isolated from 123 patients (78.8%). Among them methicillin-resistant Staphylococcus aureus (MRSA) accounted for 90.7% (49/54) and methicillin-resistant coagulase-negative Staphylococcus (MRCNS) 88.2% (30/34). The TEC susceptibility test for 105 strains showed that all of the Staphylococci and Enterococci were susceptible. In 121 strains tested for vancomycin, all of the Staphylococci but only 78.3% (18/23) of the Enterococci were susceptible. There were 18 strains of Gram negative bacilli and 1 strain of Candida A. isolated concomitantly with G(+) cocci from 17 cases. The total clinical effectiveness was 82.1% by ITT (156 cases) analysis and 85.2% by PP (135 cases) analysis, respectively. Bacteriologic eradication rate was 87.7%. Thirty three patients with negative culture result were empirically treated with TEC and had 96.8% of clinical effectiveness. The efficacy of TEC to different infections was similar. The total adverse effects, such as decrease in blood cells and transient abnormal liver functions, accounted only for 1.28%. CONCLUSIONS: Teicoplanin was a very effective antibiotic for G(+) coccus infections and safe for patients. In highly suspected infections with methicillin-resistant Staphylococci or Enterococci, TEC may be a choice for initial empirical treatment.

The relative influence of metal ion binding sites in the I-like domain and the interface with the hybrid domain on rolling and firm adhesion by integrin alpha4beta7.

We examined the effect of conformational change at the beta(7) I-like/hybrid domain interface on regulating the transition between rolling and firm adhesion by integrin alpha(4)beta(7). An N-glycosylation site was introduced into the I-like/hybrid domain interface to act as a wedge and to stabilize the open conformation of this interface and hence the open conformation of the alpha(4) beta(7) headpiece. Wild-type alpha(4)beta(7) mediates rolling adhesion in Ca(2+) and Ca(2+)/Mg(2+) but firm adhesion in Mg(2+) and Mn(2+). Stabilizing the open headpiece resulted in firm adhesion in all divalent cations. The interaction between metal binding sites in the I-like domain and the interface with the hybrid domain was examined in double mutants. Changes at these two sites can either counterbalance one another or be additive, emphasizing mutuality and the importance of multiple interfaces in integrin regulation. A double mutant with counterbalancing deactivating ligand-induced metal ion binding site (LIMBS) and activating wedge mutations could still be activated by Mn(2+), confirming the importance of the adjacent to metal ion-dependent adhesion site (ADMIDAS) in integrin activation by Mn(2+). Overall, the results demonstrate the importance of headpiece allostery in the conversion of rolling to firm adhesion.