RESUMEN

Introduction: Lead (Pb) pollution in agricultural soil has been accelerated by industrial development and human activities, and poses a major threat to agricultural ecosystems. Both biochar and arbuscular mycorrhiza (AM) fungi are considered to play an important role in remediation of Pb contaminated soil. Methods: The combined remediation effects of introduced AM fungi and biochar on soil properties, Pb availability, microbial community and functional profiles were systematically investigated in unsterilized Pb-polluted agricultural soil. Results: Results indicated that soil nutrients were significantly improved through the combined application of biochar and introduced AM fungi. The introduced AM fungi combined with biochar prepared at 400°C and 500°C promoted the transformation of Pb to a more stable state with low bioavailability. Moreover, the addition of AM fungi and biochar affected the relative abundances of dominant bacteria and fungi at the phylum and genus levels. Biochar mainly affected soil bacterial community and obviously increased the relative abundance of Actinobacteria and Blastococcus. The interactions between biochar and introduced AM fungi mainly affected fungal community, and increased the abundance of Ascomycota and Botryotrichum. Further, PICRUSt analysis indicated biochar amendment supported stronger bacterial metabolic functional potentials. Discussion: Therefore, the combined application of biochar and Therefore, the combined application of biochar and introduced AM fungi could improve soil nutrients, reduce Pb introduced AM fungi could improve soil nutrients, reduce Pb availability, availability, and show and show a positive effect on a positive effect on indigenous microbial communities and indigenous microbial communities and metabolic functions in metabolic functions in farmland soil.

RESUMEN

Polyurethane (PU) is a versatile plastic that boasts high environmental resistance. The biodegradation of PU has become a hot topic of research aimed at finding ways to potentially solve PU pollutants. Identifying microorganisms capable of efficiently degrading PU plastics is pivotal for the development of a green recycling process for PU. This study aimed to isolate and characterize PU-degrading fungi from the soil of a waste transfer station in Luoyang, China. We isolated four different fungal strains from the soil. Among the isolates, the P2072 and P2073 strains were identified as Rhizopus oryzae (internal transcribed spacer identity, 99.66%) and Alternaria alternata (internal transcribed spacer identity, 99.81%), respectively, through microscopic, morphologic, as well as 18S rRNA sequencing. The degradation ability of strains P2072 and P2073 was analyzed through measurement of weight loss, and they exhibited a degradation rate of 2.7% and 3.3%, respectively, for the PU films after 2 months' growth in mineral salt medium (MSM) with PU films as the sole carbon source. In addition, the P2073 strain exhibited protease activity in the presence of PU. To our knowledge, R. oryzae has never been reported as a PU-degrading fungus. This study provides a new perspective on the biodegradation of PU.

Asunto(s)

RESUMEN

Transcriptome analysis for the original Bacillus subtilis K1 strain and UV mutagenic strain UW07 with high yield of pectate lyase was implemented with RNA-seq. The function of genes was annotated and metabolic pathways were classified to look for different expression genes and classify these genes into related metabolic pathways to reveal the high-yield mechanism of pectate lyase in UW07. The results showed that 397 genes were up-regulated and 617 genes were down-regulated compared with the original strain. The up-regulated genes were mainly involved in ABC transporters, two-component system, biosynthesis of amino acids, and carbon metabolism.

Asunto(s)

RESUMEN

Background: Because osteoporotic vertebral fracture (OVF) on chest radiographs is commonly missed in radiological reports, we aimed to develop a software program which offers automated detection of compressive vertebral fracture (CVF) on lateral chest radiographs, and which emphasizes CVF detection specificity with a low false positivity rate. Methods: For model training, we retrieved 3,991 spine radiograph cases and 1,979 chest radiograph cases from 16 sources, with among them in total 1,404 cases had OVF. For model testing, we retrieved 542 chest radiograph cases and 162 spine radiograph cases from four independent clinics, with among them 215 cases had OVF. All cases were female subjects, and except for 31 training data cases which were spine trauma cases, all the remaining cases were post-menopausal women. Image data included DICOM (Digital Imaging and Communications in Medicine) format, hard film scanned PNG (Portable Network Graphics) format, DICOM exported PNG format, and PACS (Picture Archiving and Communication System) downloaded resolution reduced DICOM format. OVF classification included: minimal and mild grades with <20% or ≥20-25% vertebral height loss respectively, moderate grade with ≥25-40% vertebral height loss, severe grade with ≥40%-2/3 vertebral height loss, and collapsed grade with ≥2/3 vertebral height loss. The CVF detection base model was mainly composed of convolution layers that include convolution kernels of different sizes, pooling layers, up-sampling layers, feature merging layers, and residual modules. When the model loss function could not be further decreased with additional training, the model was considered to be optimal and termed 'base-model 1.0'. A user-friendly interface was also developed, with the synthesized software termed 'Ofeye 1.0'. Results: Counting cases and with minimal and mild OVFs included, base-model 1.0 demonstrated a specificity of 97.1%, a sensitivity of 86%, and an accuracy of 93.9% for the 704 testing cases. In total, 33 OVFs in 30 cases had a false negative reading, which constituted a false negative rate of 14.0% (30/215) by counting all OVF cases. Eighteen OVFs in 15 cases had OVFs of ≥ moderate grades missed, which constituted a false negative rate of 7.0% (15/215, i.e., sensitivity 93%) if only counting cases with ≥ moderate grade OVFs missed. False positive reading was recorded in 13 vertebrae in 13 cases (one vertebra in each case), which constituted a false positivity rate of 2.7% (13/489). These vertebrae with false positivity labeling could be readily differentiated from a true OVF by a human reader. The software Ofeye 1.0 allows 'batch processing', for example, 100 radiographs can be processed in a single operation. This software can be integrated into hospital PACS, or installed in a standalone personal computer. Conclusions: A user-friendly software program was developed for CVF detection on elderly women's lateral chest radiographs. It has an overall low false positivity rate, and for moderate and severe CVFs an acceptably low false negativity rate. The integration of this software into radiological practice is expected to improve osteoporosis management for elderly women.

RESUMEN

Background: In the process of percutaneous coronary intervention (PCI), patients with ST-segment elevation myocardial infarction (STEMI) may receive large doses of the iodine contrast agent. Some adverse events may be aroused if the patients receive the gadolinium agents. We investigate the association between cine cardiac magnetic resonance (CMR)-based radiomics signature and microvascular obstruction (MVO) in patients with STEMI. Methods: A total of 116 STEMI patients who received continuous CMR within 6 days after PCI were retrospectively included in this study. According to the late gadolinium enhancement (LGE) of CMR, the myocardial infarction (MI) was divided into with and without MVO. Radiomic features were extracted from cine CMR images and the least absolute shrinkage and selectionator operator (LASSO) algorithm was used for features selection and radiomic signatures construction. Binary logistic regression was used to assess association between radiomic signatures and MVO with adjusted for baseline clinical characteristics. Results: Of 116 patients with STEMI, MI with MVO was found in 50 patients and MI without MVO was found in 66 patients. LASSO regression selected five radiomics features for radiomics signature construction. Logistic regression revealed that radiomics score, high sensitivity C-reactive protein (hs-CRP) and creatine phosphokinases (CPK) were independent risk factors for MVO with odds ratio (OR) of 4.41 (95% CI: 2.26-9.93), 1.018 (95% CI: 1.006-1.034) and 1.0007 (95% CI: 1.0004-1.0012), respectively. Area under curve (AUC) of receiver operating characteristic (ROC) of radiomics score to predict MVO was 0.75 (95% CI: 0.68-0.85). Conclusions: Cine CMR-based radiomics signature was an independent predictive factor of MVO in patients with STEMI, which showed the potential of this contrast free radiomics signature to be an imaging biomarker for MVO.

RESUMEN

INTRODUCTION: To develop and validate a simple-to-use nomogram based on preoperative CT to predict spread through air space (STAS) status of stage IA lung adenocarcinoma (ADC). METHODS: In this retrospective study, 434 patients with pathological proven periphery stage IA lung adenocarcinoma were included, which consisted of 349 patients from center I for training group and 85 patients from Center II for test group. STAS was identified in 53 patients (40 patient in the training group and 13 patients in the test group). On the basis of preoperative CT images, 19 morphological characteristics were analyzed. Univariable analysis was used to explore the association between clinical and CT characteristics and STAS status in the training group (P < 0.002). Independent risk factors for STAS were identified using multivariable logistic regression analysis and then used to build a nomogram for preoperative predicting STAS status. RESULTS: Type of nodules, diameter of solid component, lobulation and percentage of the solid component (PSC) were associated with STAS status of peripheral stage IA lung ADCs statistical significantly. Multivariate logistics regression analysis revealed that PSC and lobulation were independent risk factors for STAS. The nomogram based on these factors achieved good predictive performance for STAS with a C-index of 0.803 in the training group and a well-fitted calibration curve. Using a cut-off value which was obtained from Youden index of the receiver operating characteristic (ROC) curve, a diagnosis accuracy of 70.6% was obtained in the test group with sensitivity, specificity, positive prediction value (PPV) and negative prediction value (NPV) of 92.3%, 66.7%, 33.3% and 98.0%, respectively. CONCLUSION: The nomogram based on preoperative CT images could achieve good predictive performance for STAS status of lung adenocarcinomas. This simple-to-used model can facilitate surgeons for a rational operation pattern choice at bedside.

Asunto(s)

RESUMEN

In this work, an exploratory study was conducted to examine Gram staining based on the capillary tube. Each Gram staining step for all bacterial strains tested was completed in capillary tubes. The results showed that different Gram staining morphologies were clearly visible in the capillary tubes. The results presented here demonstrated that the improved method could effectively distinguish between Gram-positive and Gram-negative bacteria, and only small volumes of reagents were required in this method. Collectively, this efficient method could rapidly and accurately identify the types of bacteria. Therefore, our findings could be used as a useful reference study for other staining methods.

Asunto(s)

RESUMEN

A simple and valid ultraviolet (UV) spectrophotometric method for the determination of poly(γ-glutamic acid) is developed. The method is based on the UV absorption spectrum of γ-PGA in aqueous solution, which exhibits a maximum absorption wavelength at 216 nm. The results obtained were comparable to those obtained with the reported high-performance liquid chromatography (HPLC) method according to ICH guidelines. Under the proposed procedure, the calibration graph is linear over the range of 20-200 µg/ml with regression correlation coefficient of 0.9997. Precision (%R.S.D.<1.50) and recovery (%R.>99.29%) are good. The limit of detection (LOD) and limit of quantitation (LOQ) are 0.39 and 1.19 µg/ml, respectively. These results agree well with those of HPLC method. Its spectrum properties studies showed that the spectrum of γ-PGA remarkably changed with an increase in temperature due to γ-PGA was digested into glutamate monomer. In spite of this, the determining procedure could carried out in a wide temperature range (25-50°C). In addition, the method is not influenced by the molecular weight, but the measurement system need to control in pH 3.0-10.0 and ionic strength not more than 0.5M. The proposed method is applied successfully for high-throughput quantification of poly(γ-glutamic acid) in biological samples. The advantages of the UV method are simplicity of operation, rapidity, sensitive, low-cost and high-throughput.

Asunto(s)

RESUMEN

An intracellular α-glucosidase with high transglycosylation activity was purified from a mutant strain of Aspergillus niger M-1 by sequential chromatography using a DEAE-cellulose 52 column, a DEAE-Sepharose CL-6B column, and a Sephadex G-100 column. The molecular mass of the purified enzyme was determined to be 116 kD with no subunits and a pI of 5.23. Maximal α-glucosidase activity occurred at pH 6.0 and 50°C. The N-terminal amino acid sequences were identified as N-SVPGTEYVV-. The presence of Ca(2+) enhanced the enzyme activity by 20%, while the α-glucosidase activity was strongly inhibited by p-chloromercuribenzoate, N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride, monochloroacetic acid, and 2-mercaptoethanol. In addition, Ag(+), n-bromosuccinimide, and acetylacetone inhibited enzyme activity by 70%, 50%, and 22%, respectively. K(m) values of 4.32 m mol L(-1) and V(max) of 3.10 × 10(-2) mol L(-1) min(-1) were found for methyl-α-D-glucopyranoside (α-MG). Maltose was identified as the preferred substrate. The high-performance liquid chromatography (HPLC) analysis indicated that the oligosaccharide products contained 10.54% of isomaltose, 8.08% of panose, and 9.29% of isomaltotriose, and the amount of glucose, maltose, maltotriose, and maltotetrose was dropped from 22.21% to 15.80% using the purified enzyme in the solution of 25% maltose and 3% glucose. This intracellular α-glucosidase has potential applications in the synthesis of sugar derivatives and the investigation of associated mechanisms.

Asunto(s)

RESUMEN

A novel high-throughput method was established for rapid screening of large numbers of Aspergillus niger mutants with high transglucosylation activity by exploiting that yeast can hardly hydrolyze isomaltooligosaccharides (IMO). Supernatants of A. niger fermentation were incubated with Saccharomyces cerevisiae to remove glucose and maltose, and the remaining non-reducing sugars, which is positively correlated with the amount of IMO, the products of transglucosylation reaction, were used as indicator of transglucosidase activity of A. niger and examined by dinitrosalicylic acid assay. Using this method, 15 stains that could convert liquefied cassava starch to IMO more efficiently were selected from 8721 A. niger mutants. Among them, mutant C-6181 strain had transglycosidase activity of 4.61 U/ml (increased by 122% compared to its parental strain) and IMO yield of 83.7%. Taking together, the method is easy, simple, efficient and cheap, and has great application potential in selection of transglucosidase-producing strains used in industrial IMO fermentation.