Metabolomics investigation of global responses of Cronobacter sakazakii against common sanitizing in infant formula processing environments.

Cronobacter sakazakii, an opportunistic bacterium, has raised a serious outbreak in powdered infant formula recent years. In this work, four sanitizing strategies used during infant formula processing, including chlorine, quaternary ammonium chloride (QAC), 60 °C heating, and malic acid (MA), were utilized against C. sakazakii among planktonic, air-dried (A), and air-dried & washed (AW) state, followed by an exploration of the metabolic responses induced by these treatments via a dual-platform metabolomics analysis with the ultra-high performance liquid chromatography-mass spectrometry and nuclear magnetic resonance. In the planktonic state, MA was the most effective in inhibiting bacterial growth, followed by chlorine, QAC, and 60 °C heating. Under A state, the efficacy of heating improved considerably, compared to that in the planktonic state, and remained unaltered under AW state. Chlorine and QAC were ineffective to control bacterial growth under A state, but their efficacy rose under AW state. Furthermore, the metabolomic analysis revealed chlorine induces amino acids catabolism, membrane lysis, and depression in carbohydrate and nucleotide metabolism in both planktonic and AW states, while the initiation of antioxidation mechanism was only found under AW state. Although the metabolic change caused by QAC in the planktonic state was similar to chlorine, the accumulation of osmoprotectant and membrane phospholipids within the AW cells reflected the effort to restore intracellular homeostasis upon QAC. Heating was characterized by considerable amino acid anabolism, along with mildly perturbed carbohydrate and nucleotide metabolism for heat shock protein preparation in both states. Lastly, MA promoted amino acid-dependent acid resistance under the planktonic state, and the regulation of antioxidation and osmoprotection under AW state. The metabolomics study elucidated the intracellular perturbation induced by common sanitizing, as well as the bacterial response, which provides insights for novel sanitization development.

Dual-Species Biofilms Formed by Escherichia coli and Salmonella Enhance Chlorine Tolerance.

In this research, mono- and dual-species biofilms of Escherichia coli (O45:H2 and O121:H19) and Salmonella enterica serovar Typhimurium formed on stainless-steel coupons were treated with 100 mg/L NaClO for 1 min. Confocal laser scanning microscopy (CLSM) was applied to investigate the spatial structural dynamics of mono- and dual-species biofilms, and nuclear magnetic resonance (NMR) spectroscopy was employed to further investigate their metabolic responses toward chlorine. CLSM results indicated that mixed-species biofilms (total biovolume, 148,000 to 167,000 µm3) stimulated the growth of biomass 2 to 6 times that of single-species biofilms. Upon chlorine treatment, E. coli O45 and S. Typhimurium achieved less reduction (P < 0.05) when coexisting in mixed biofilms (0.70 and 1.17 log CFU/coupon reductions, respectively) compared with their corresponding single-species biofilms (1.97 and 2.01 log CFU/coupon reductions, respectively), while for E. coli O121, more reduction (P < 0.05) was achieved in a mixed biofilm (1.37 log CFU/coupon reductions) compared with its single-species biofilm (0.59 log CFU/coupon reductions). Moreover, NMR results suggested that the increase of putrescine (antioxidation regulator) and the decrease of glucose (enhanced glycolysis for energy replenishment) might contribute to the improved chlorine tolerance in mixed biofilms. Overall, dual-species biofilms promoted biofilm growth and their chlorine tolerance. This study improved our knowledge of the metabolic difference of single- and mixed-species biofilms of E. coli and Salmonella to chlorine sanitization and raised an urgency to investigate the effectiveness of common disinfectants against multispecies consortia. IMPORTANCE Outbreaks of Escherichia coli and Salmonella in food might be associated with the cross-contamination of biofilms on food-contact surfaces. The knowledge of the sanitization of mono-species biofilm on the food-contact surface is well established, while mixed-species biofilm occurs more naturally, which could profoundly affect the efficacy of sanitizer. Therefore, this research aims to evaluate the efficacy of using chlorine against single- and dual-species biofilms of E. coli and Salmonella along with the underlying bacterial metabolic responses. The responses of a mixed biofilm of E. coli and Salmonella to chlorine sanitization were clarified, providing insights to develop a targeted and green sanitization strategy against specific pathogens by perturbing their most susceptible metabolism pathway without sanitizer residue.

Long read sequencing of Toona sinensis (A. Juss) Roem: A chromosome-level reference genome for the family Meliaceae.

Chinese mahogany (Toona sinensis) is a woody plant that is widely cultivated in China and Malaysia. Toona sinensis is important economically, including as a nutritious food source, as material for traditional Chinese medicine and as a high-quality hardwood. However, the absence of a reference genome has hindered in-depth molecular and evolutionary studies of this plant. In this study, we report a high-quality T. sinensis genome assembly, with scaffolds anchored to 28 chromosomes and a total assembled length of 596 Mb (contig N50 = 1.5 Mb and scaffold N50 = 21.5 Mb). A total of 34,345 genes were predicted in the genome after homology-based and de novo annotation analyses. Evolutionary analysis showed that the genomes of T. sinensis and Populus trichocarpa diverged ~99.1-103.1 million years ago, and the T. sinensis genome underwent a recent genome-wide duplication event at ~7.8 million years and one more ancient whole genome duplication event at ~71.5 million years. These results provide a high-quality chromosome-level reference genome for T. sinensis and confirm its evolutionary position at the genomic level. Such information will offer genomic resources to study the molecular mechanism of terpenoid biosynthesis and the formation of flavour compounds, which will further facilitate its molecular breeding. As the first chromosome-level genome assembled in the family Meliaceae, it will provide unique insights into the evolution of members of the Meliaceae.

Evaluate the performance of four artificial intelligence-aided diagnostic systems in identifying and measuring four types of pulmonary nodules.

PURPOSE: This study aims to evaluate the performance of four artificial intelligence-aided diagnostic systems in identifying and measuring four types of pulmonary nodules. METHODS: Four types of nodules were implanted in a commercial lung phantom. The phantom was scanned with multislice spiral computed tomography, after which four systems (A, B, C, D) were used to identify the nodules and measure their volumes. RESULTS: The relative volume error (RVE) of system A was the lowest for all nodules, except for small ground glass nodules (SGGNs). System C had the smallest RVE for SGGNs, -0.13 (-0.56, 0.00). In the Bland-Altman test, only systems A and C passed the consistency test, P = 0.40. In terms of precision, the miss rate (MR) of system C was 0.00% for small solid nodules (SSNs), ground glass nodules (GGNs), and solid nodules (SNs) but 4.17% for SGGNs. The comparable system D MRs for SGGNs, SSNs, and GGNs were 71.30%, 25.93%, and 47.22%, respectively, the highest among all the systems. Receiver operating characteristic curve analysis indicated that system A had the best performance in recognizing SSNs and GGNs, with areas under the curve of 0.91 and 0.68. System C had the best performance for SGGNs (AUC = 0.91). CONCLUSION: Among four types nodules, SGGNs are the most difficult to recognize, indicating the need to improve higher accuracy and precision of artificial systems. System A most accurately measured nodule volume. System C was most precise in recognizing all four types of nodules, especially SGGN.

Influence of CT effective dose and convolution kernel on the detection of pulmonary nodules in different artificial intelligence software systems: A phantom study.

PURPOSE: To investigate the effective dose (E) and convolution kernel's effects on the detection of pulmonary nodules in different artificial intelligence (AI) software systems. METHODS: Simulated nodules of various sizes and densities in the Lungman phantom were CT scanned at different levels of E (3 - 5, 1 - 3, 0.5 - 1, and <0.5 mSv) and were reconstructed with different kernels (B30f, B60f, and B80f). The number of nodules and corresponding volumes in different images were detected by four AI software systems (A, B, C, and D). Sensitivity, false positives (FPs), false negatives (FNs), and relative volume error (RVE) were calculated and compared to the aspects of the E and convolution kernel. RESULTS: System B had the highest median sensitivity (100 %). The median FPs of systems B (1) and D (1) was lower than A (11.5) and C (5). System D had the smallest RVE (13.12 %). When the E was <0.5 mSv, system D's sensitivity decreased, while the FPs and FNs of systems A and B increased significantly (P < 0.05). When the kernel was changed from B80f to B30f, the FPs of system A decreased, while that of system C increased, and the RVE of systems A, B, and C increased (P < 0.05). CONCLUSION: AI software systems B and D have high detection efficiency under normal or low dose conditions and show better stability. However, the detection efficiency of systems A and C would be affected by the E or convolution kernel, but the E would not affect the volume measurement of four systems.

Membrane functionalization of polymersomes: alleviating mass transport limitations by integrating multiple selective membrane transporters for the diffusion of chemically diverse molecules.

Recently, the interest in polymersomes as nanoreactors for synthetic applications has increased due to interesting proof-of-concept studies, indicating a versatile use of polymeric vesicles to compartmentalize complex reaction cascades. However, the low permeability of polymeric membranes and the requirement for a controlled mass transport across the compartment boundaries have posed a major limitation to the broad applicability of polymersomes for synthetic reactions. Current advances in the functional integration of membrane proteins (MPs) into poly(2-dimethylsiloxane)-based membranes have allowed the selective increase of the permeability for a controlled mass transport of the desired compounds across the membrane. Herein we demonstrate that polymer membranes are capable of harboring different MPs to alleviate the mass transport limitations of chemically diverse molecules, thereby enabling complex cascade reactions to be performed within the nanoreactors. The ability to functionalize the polymer membrane with multiple, highly selective MPs allows a reduction in mass transport limitations without abandoning compartmentalization of the reaction space on a low molecular mass level. As the model reaction, a two enzyme system consisting of a ketoreductase (KR) and a formate dehydrogenase was studied. For the transport of the hydrophobic substrate and product of the KR, the MPs AlkL, OmpW, OprG and TodX were investigated. For the transport of formate, OmpF, PhoE and FocA were used. AlkL showed the highest integration efficiency (39%) and a maximum of 120 AlkL molecules were successfully inserted into each polymersome. The highest channel-specific effects on the mass transfer were achieved using TodX and PhoE, respectively. The combination of both proteins led to an improvement of the space-time yield of the product (S)-pentafluorophenyl ethanol by 2.32-fold compared to nanoreactors without MPs.

High-level production of the industrial product lycopene by the photosynthetic bacterium Rhodospirillum rubrum.

The biosynthesis of the major carotenoid spirilloxanthin by the purple nonsulfur bacterium Rhodospirillum rubrum is thought to occur via a linear pathway proceeding through phytoene and, later, lycopene as intermediates. This assumption is based solely on early chemical evidence (B. H. Davies, Biochem. J. 116:93-99, 1970). In most purple bacteria, the desaturation of phytoene, catalyzed by the enzyme phytoene desaturase (CrtI), leads to neurosporene, involving only three dehydrogenation steps and not four as in the case of lycopene. We show here that the chromosomal insertion of a kanamycin resistance cassette into the crtC-crtD region of the partial carotenoid gene cluster, whose gene products are responsible for the downstream processing of lycopene, leads to the accumulation of the latter as the major carotenoid. We provide spectroscopic and biochemical evidence that in vivo, lycopene is incorporated into the light-harvesting complex 1 as efficiently as the methoxylated carotenoids spirilloxanthin (in the wild type) and 3,4,3',4'-tetrahydrospirilloxanthin (in a crtD mutant), both under semiaerobic, chemoheterotrophic, and photosynthetic, anaerobic conditions. Quantitative growth experiments conducted in dark, semiaerobic conditions, using a growth medium for high cell density and high intracellular membrane levels, which are suitable for the conventional industrial production in the absence of light, yielded lycopene at up to 2 mg/g (dry weight) of cells or up to 15 mg/liter of culture. These values are comparable to those of many previously described Escherichia coli strains engineered for lycopene production. This study provides the first genetic proof that the R. rubrum CrtI produces lycopene exclusively as an end product.

[Effect of skull acupuncture and scalp acupuncture on serum vascular endothelial growth factor in the patient of acute cerebral infarction].

OBJECTIVE: To investigate effect of skull suture acupuncture (skull acupuncture) and scalp acupuncture on serum vascular endothelial growth factor (VEGF) in the patient of acute cerebral infarction (CI). METHODS: Twenty cases of CI were treated with skull suture acupuncture at coronal suture, sagittal suture, lambdoid suture, etc. combined with medication (group B), group C (n=20) with scalp acupuncture at contralateral Dingnie Qian-xiexian (MS 6) and Dingnie Houxiexian (MS 7) plus medication, and group A (n=20) with medication. Changes of serum VEGF contents were investigated in the three groups. RESULTS: After treatment, the serum VEGF content did not significantly change in group A (P > 0.05), and significantly increased in group B and group C (P < 0.01, P < 0.05), with significant difference as group B and C compared with that of group A (P < 0.05), and with no significant difference between group B and group C (P > 0.05). CONCLUSION: Skull suture acupuncture combined with medication and scalp acupuncture plus medication have a similar effect on serum VEGF in the patient of acute cerebral infarction.