Complete genome sequence of antibiotic-producing Streptomyces sp. HBERC⁃20821, isolated from Wawushan Hill, Sichuan Province, China.

The complete genome of a Streptomyces capable of producing multiple antibiotics was sequenced. Strain HBERC-20821 was isolated from a soil sample collected at Wawushan Hill, Sichuan Province, China. Genomic information will facilitate our systematic genetic manipulation of the strain at the gene level, enhancing its antibiotic production.

Potential increased propofol sensitivity in cognitively impaired elderly: a controlled, double-blind study.

Background: Cognitive impairment in the elderly may lead to potential increased sensitivity to anesthetic agents targeting receptors associated with cognition. This study aimed to explore the effect of cognitive status on propofol consumption during surgery in elderly patients. Methods: Sixty elderly patients scheduled for laparoscopic radical prostatectomy were allocated to either a cognitively normal [CogN, Montreal Cognitive Assessment (MoCA) score ≥26] or cognitively impaired (CogI, MoCA <26) group. Propofol was administered via target-controlled infusion to maintain a bispectral index (BIS) between 55-65 during surgery. Propofol consumption was recorded at three time points: T1 (abolished eyelash reflex), T2 (BIS = 50), T3 (extubation). BIS values at eyelash reflex abolition were also recorded. Postoperative MoCA, Visual Analogue Scale (VAS) scores, and remifentanil/sufentanil consumption were assessed. Results: BIS values before induction were similar between CogN and CogI groups. However, at eyelash reflex abolition, BIS was significantly higher in CogI than CogN (mean ± SD: 65.3 ± 7.2 vs. 61.1 ± 6.8, p = 0.031). Propofol requirement to reach BIS 50 was lower in CogI vs. CogN (1.24 ± 0.19 mg/kg vs. 1.46 ± 0.12 mg/kg, p = 0.003). Postoperative MoCA, VAS scores, and remifentanil/sufentanil consumption did not differ significantly between groups. Conclusion: Compared to cognitively intact elderly, those with cognitive impairment exhibited higher BIS at eyelash reflex abolition and required lower propofol doses to achieve the same BIS level, suggesting increased propofol sensitivity. Cognitive status may impact anesthetic medication requirements in the elderly.

HbBIN2 Functions in Plant Cold Stress Resistance through Modulation of HbICE1 Transcriptional Activity and ROS Homeostasis in Hevea brasiliensis.

Cold stress poses significant limitations on the growth, latex yield, and ecological distribution of rubber trees (Hevea brasiliensis). The GSK3-like kinase plays a significant role in helping plants adapt to different biotic and abiotic stresses. However, the functions of GSK3-like kinase BR-INSENSITIVE 2 (BIN2) in Hevea brasiliensis remain elusive. Here, we identified HbBIN2s of Hevea brasiliensis and deciphered their roles in cold stress resistance. The transcript levels of HbBIN2s are upregulated by cold stress. In addition, HbBIN2s are present in both the nucleus and cytoplasm and have the ability to interact with the INDUCER OF CBF EXPRESSION1(HbICE1) transcription factor, a central component in cold signaling. HbBIN2 overexpression in Arabidopsis displays decreased tolerance to chilling stress with a lower survival rate and proline content but a higher level of electrolyte leakage (EL) and malondialdehyde (MDA) than wild type under cold stress. Meanwhile, HbBIN2 transgenic Arabidopsis treated with cold stress exhibits a significant increase in the accumulation of reactive oxygen species (ROS) and a decrease in the activity of antioxidant enzymes. Further investigation reveals that HbBIN2 inhibits the transcriptional activity of HbICE1, thereby attenuating the expression of C-REPEAT BINDING FACTOR (HbCBF1). Consistent with this, overexpression of HbBIN2 represses the expression of CBF pathway cold-regulated genes under cold stress. In conclusion, our findings indicate that HbBIN2 functions as a suppressor of cold stress resistance by modulating HbICE1 transcriptional activity and ROS homeostasis.

Improving the Activity of Tryptophan Synthetase via a Nucleic Acid Scaffold.

Tryptophan synthetase (TSase), which functions as a tetramer, is a typical enzyme with a substrate channel effect, and shows excellent performance in the production of non-standard amino acids, histamine, and other biological derivatives. Based on previous work, we fused a mutant CE protein (colistin of E. coli, a polypeptide with antibacterial activity) sequence with the sequence of TSase to explore whether its catalytic activity could be enhanced, and we also analyzed whether the addition of a DNA scaffold was a feasible strategy. Here, dCE (CE protein without DNase activity) protein tags were constructed and fused to the TrapA and TrapB subunits of TSase, and the whole cell was used for the catalytic reaction. The results showed that after the dCE protein tag was fused to the TrapB subunit, its whole cell catalytic activity increased by 50%. Next, the two subunits were expressed separately, and the proteins were bound in vitro to ensure equimolar combination between the two subunits. After the dCE label was fused to TrapB, the activity of TSase assembled with TrapA also improved. A series of experiments revealed that the enzyme fused with dCE9 showed higher activity than the wild-type protein. In general, the activity of assembly TSase was optimal when the temperature was 50 °C and the pH was about 9.0. After a long temperature treatment, the enzyme maintained good activity. With the addition of exogenous nucleic acid, the activity of the enzyme increased. The maximum yield was 0.58 g/L, which was almost three times that of the wild-type TSase (0.21 g/L). The recombinant TSase constructed in this study with dCE fusion had the advantages of higher heat resistance and higher activity, and confirmed the feasibility of adding a nucleic acid scaffold, providing a new idea for the improvement of structurally similar enzymes.

Current Insights on the Diverse Structures and Functions in Bacterial Collagen-like Proteins.

The dearth of knowledge on the diverse structures and functions in bacterial collagen-like proteins is in stark contrast to the deep grasp of structures and functions in mammalian collagen, the ubiquitous triple-helical scleroprotein that plays a central role in tissue architecture, extracellular matrix organization, and signal transduction. To fill and highlight existing gaps due to the general paucity of data on bacterial CLPs, we comprehensively reviewed the latest insight into their functional and structural diversity from multiple perspectives of biology, computational simulations, and materials engineering. The origins and discovery of bacterial CLPs were explored. Their genetic distribution and molecular architecture were analyzed, and their structural and functional diversity in various bacterial genera was examined. The principal roles of computational techniques in understanding bacterial CLPs' structural stability, mechanical properties, and biological functions were also considered. This review serves to drive further interest and development of bacterial CLPs, not only for addressing fundamental biological problems in collagen but also for engineering novel biomaterials. Hence, both biology and materials communities will greatly benefit from intensified research into the diverse structures and functions in bacterial collagen-like proteins.

Complete Genome Sequence of Brachybacterium sp. Strain NBEC-018, Isolated from Nematode-Infected Potatoes.

Brachybacterium species are ubiquitous Gram-positive bacteria. Here, we report the complete genome sequence of Brachybacterium sp. strain NBEC-018. The strain was isolated from rotten potatoes that were infected with potato rot nematodes (Ditylenchus destructor). The genome sequence will be beneficial to clarify the ecological role of Brachybacterium species.

Acaricidal Activity and Field Efficacy Analysis of the Potential Biocontrol Agent Bacillus vallismortis NBIF-001 against Spider Mites.

In recent years, spider mites have caused considerable economic losses to global agriculture. However, currently available management strategies are limited because of the rapid development of resistance. In this study, Bacillus vallismortis NBIF-001 was isolated and evaluated for its acaricidal activity. NBIF-001 exhibited a significant lethal effect on spider mites within 48 h. The median lethal concentration (LC50) of the culture powders (3.2 × 1010 CFU/g) was 50.2 µg/mL for Tetranychus urticae (red form), 18.0 µg/mL for T. urticae (green form), and 15.7 µg/mL for Panonychus citri (McGregor). Cultivation optimisation experiments showed that when the number of spores increased, fermentation toxicity also increased. Moreover, field experiments demonstrated that NBIF-001 performed well in the biocontrol of P. citri, which showed a similar corrected field efficacy with the chemical control (67.1 ± 7.9% and 71.1 ± 6.4% after 14 days). Genomics analysis showed that NBIF-001 contains 231 factors and seven gene clusters of metabolites that may be involved in its acaricidal activity. Further bioassays of the fermentation supernatants showed that 50× dilution treatments killed 72.5 ± 5.4% of the mites in 48 h, which was similar with those of the broth. Bioassays of the supernatant proteins confirmed that various proteins exhibited acaricidal activity. Five candidate proteins were expressed and purified successfully. The bioassays showed that the small protein BVP8 exhibited significant acaricidal activity with an LC50 of 12.4 µg/mL (T. urticae). Overall, these findings suggest that B. vallismortis NBIF-001 is a potential biocontrol agent for spider mite management.

Sulfenylation of ENOLASE2 facilitates H2O2-conferred freezing tolerance in Arabidopsis.

H2O2 affects the expression of genes that are involved in plant responses to diverse environmental stresses; however, the underlying mechanisms remain elusive. Here, we demonstrate that H2O2 enhances plant freezing tolerance through its effect on a protein product of low expression of osmotically responsive genes2 (LOS2). LOS2 is translated into a major product, cytosolic enolase2 (ENO2), and sometimes an alternative product, the transcription repressor c-Myc-binding protein (MBP-1). ENO2, but not MBP-1, promotes cold tolerance by binding the promoter of C-repeat/DRE binding factor1 (CBF1), a central transcription factor in plant cold signaling, thus activating its expression. Overexpression of CBF1 restores freezing sensitivity of a LOS2 loss-of-function mutant. Furthermore, cold-induced H2O2 increases nuclear import and transcriptional binding activity of ENO2 by sulfenylating cysteine 408 and thereby promotes its oligomerization. Collectively, our results illustrate how H2O2 activates plant cold responses by sulfenylating ENO2 and promoting its oligomerization, leading to enhanced nuclear translocation and transcriptional activation of CBF1.

HbSnRK2.6 Functions in ABA-Regulated Cold Stress Response by Promoting HbICE2 Transcriptional Activity in Hevea brasiliensis.

Low temperature remarkably limits rubber tree (Hevea brasiliensis Muell. Arg.) growth, latex production, and geographical distribution, but the underlying mechanisms of Hevea brasiliensis cold stress response remain elusive. Here, we identified HbSnRK2.6 as a key component in ABA signaling functions in phytohormone abscisic acid (ABA)-regulated cold stress response in Hevea brasiliensis. Exogenous application of ABA enhances Hevea brasiliensis cold tolerance. Cold-regulated (COR) genes in the CBF pathway are upregulated by ABA. Transcript levels of all five HbSnRK2.6 members are significantly induced by cold, while HbSnRK2.6A, HbSnRK2.6B, and HbSnRK2.6C can be further activated by ABA under cold conditions. Additionally, HbSnRK2.6s are localized in the cytoplasm and nucleus, and can physically interact with HbICE2, a crucial positive regulator in the cold signaling pathway. Overexpression of HbSnRK2.6A or HbSnRK2.6B in Arabidopsis extensively enhances plant responses to ABA and expression of COR genes, leading to increased cold stress tolerance. Furthermore, HbSnRK2.6A and HbSnRK2.6B can promote transcriptional activity of HbICE2, thus, increasing the expression of HbCBF1. Taken together, we demonstrate that HbSnRK2.6s are involved in ABA-regulated cold stress response in Hevea brasiliensis by regulating transcriptional activity of HbICE2.

Complete Genome Sequence of Bacillus badius NBPM-293, a Plant Growth-Promoting Strain Isolated from Rhizosphere Soil.

Bacillus species have a long history of widespread use in biocontrol and crop growth-promoting fields. Here, we present the genome sequence of the rhizobacterium B. badius NBPM-293. The genome sequence will provide valuable information for a better understanding of the mechanism of plant growth promotion.

Adverse effects of Alport syndrome-related Gly missense mutations on collagen type IV: Insights from molecular simulations and experiments.

Patients with Alport syndrome (AS) exhibit blood and elevated protein levels in their urine, inflamed kidneys, and many other abnormalities. AS is attributed to mutations in type IV collagen genes, particularly glycine missense mutations in the collagenous domain of COL4A5 that disrupt common structural motifs in collagen from the repeat (Gly-Xaa-Yaa)n amino acid sequence. To characterize and elucidate the molecular mechanisms underlying how AS-related mutations perturb the structure and function of type IV collagen, experimental studies and molecular simulations were integrated to investigate the structure, stability, protease sensitivity, and integrin binding affinity of collagen-like proteins containing amino acid sequences from the α5(IV) chain and AS-related Gly missense mutations. We show adverse effects where (i) three AS-related Gly missense mutations significantly reduced the structural stability of the collagen in terms of decreased melting temperatures and calorimetric enthalpies, in conjunction with a collective drop in the external work needed to unfold the peptides containing mutation sequences; (ii) due to local unwinding around the sites of mutations, these triple helical peptides were also degraded more rapidly by trypsin and chymotrypsin, as these enzymes could access the collagenous triple helix more easily and increase the number of contacts; (iii) the mutations further abolished the ability of the recombinant collagens to bind to integrins and greatly reduced the binding affinities between collagen and integrins, thus preventing cells from adhering to these mutants. Our unified experimental and computational approach provided underlying insights needed to guide potential therapies for AS that ameliorate the adverse effects from AS disease onset and progression.

Thermoplastic moulding of regenerated silk.

Early insights into the unique structure and properties of native silk suggested that ß-sheet nanocrystallites in silk would degrade prior to melting when subjected to thermal processing. Since then, canonical approaches for fabricating silk-based materials typically involve solution-derived processing methods, which have inherent limitations with respect to silk protein solubility and stability in solution, and time and cost efficiency. Here we report a thermal processing method for the direct solid-state moulding of regenerated silk into bulk 'parts' or devices with tunable mechanical properties. At elevated temperature and pressure, regenerated amorphous silk nanomaterials with ultralow ß-sheet content undergo thermal fusion via molecular rearrangement and self-assembly assisted by bound water to form a robust bulk material that retains biocompatibility, degradability and machinability. This technique reverses presumptions about the limitations of direct thermal processing of silk into a wide range of new material formats and composite materials with tailored properties and functionalities.

Propofol alleviates cisplatin-related cognitive impairment.

Chemotherapy-related cognitive impairment (CRCI) is commonly reported following the administration of chemotherapeutic agents and comprises a wide variety of neurological problems. Many patients after chemotherapy need further surgery under anesthesia. Thus, in this study, we examined whether propofol, one of the most commonly used anesthetics in surgery, could further affect the cognitive abilities in mouse CRCI models. The mice were injected intraperitoneally with cisplatin (2 mg/kg/day) for continuous 10 days and showed significantly reduced body weights. After 10 days reconversion, mice with cisplatin injection showed impaired memory retention in the inhibitory avoidance (IA) task, mimicking the CRCI in patients. Then, we found that a single injection of propofol with the sub-anesthetic dosage (50 mg/kg) but not the anesthetic dosage (250 mg/kg) could significantly alleviate the cisplatin-induced memory impairment. These results imply the possible clinical application of propofol, especially at the sub-anesthetic dosage, in the surgery of patients after chemotherapy.

Deciphering metabolic responses of biosurfactant lichenysin on biosynthesis of poly-γ-glutamic acid.

Poly-γ-glutamic acid (γ-PGA) is an extracellularly produced biodegradable polymer, which has been widely used as agricultural fertilizer, mineral fortifier, cosmetic moisturizer, and drug carrier. This study firstly discovered that lichenysin, as a biosurfactant, showed the capability to enhance γ-PGA production in Bacillus licheniformis. The exogenous addition of lichenysin improved the γ-PGA yield up to 17.9% and 21.9%, respectively, in the native strain B. licheniformis WX-02 and the lichenysin-deficient strain B. licheniformis WX02-ΔlchAC. The capability of intracellular biosynthesis of lichenysin was positively correlated with γ-PGA production. The yield of γ-PGA increased by 25.1% in the lichenysin-enhanced strain B. licheniformis WX02-Psrflch and decreased by 12.2% in the lichenysin-deficient strain WX02-ΔlchAC. Analysis of key enzyme activities and gene expression in the TCA cycle, precursor glutamate synthesis, and γ-PGA synthesis pathway revealed that the existence of lichenysin led to increased γ-PGA via shifting the carbon flux in the TCA cycle towards glutamate and γ-PGA biosynthetic pathways, minimizing by-product formation, and facilitating the uptake of extracellular substrates and the polymerization of glutamate to γ-PGA. Insight into the mechanisms of enhanced production of γ-PGA by lichenysin would define the essential parameters involved in γ-PGA biosynthesis and provide the basis for large-scale production of γ-PGA.

Enzymatic Phosphorylation of Ser in a Type I Collagen Peptide.

Phosphoproteomics studies have reported phosphorylation at multiple sites within collagen, raising the possibility that these post-translational modifications regulate the physical or biological properties of collagen. In this study, molecular dynamics simulations and experimental studies were carried out on model peptides to establish foundational principles of phosphorylation of Ser residues in collagen. A (Gly-Xaa-Yaa)11 peptide was designed to include a Ser-containing sequence from type I collagen that was reported to be phosphorylated. The physiological kinase involved in collagen phosphorylation is not known. In vitro studies showed that a model kinase ERK1 (extracellular signal-regulated protein kinase 1) would phosphorylate Ser within the consensus sequence if the collagen-like peptide is in the denatured state but not in the triple-helical state. The peptide was not a substrate for FAM20C, a kinase present in the secretory pathway, which has been shown to phosphorylate many extracellular matrix proteins. The unfolded single chain (Gly-Xaa-Yaa)11 peptide containing phosphoSer was able to refold to form a stable triple helix but at a reduced folding rate and with a small decrease in thermal stability relative to the nonphosphorylated peptide at neutral pH. These biophysical studies on model peptides provide a basis for investigations into the physiological consequences of collagen phosphorylation and the application of phosphorylation to regulate the properties of collagen biomaterials.

Collagen Gly missense mutations: Effect of residue identity on collagen structure and integrin binding.

Gly missense mutations in type I collagen, which replace a conserved Gly in the repeating (Gly-Xaa-Yaa)n sequence with a larger residue, are known to cause Osteogenesis Imperfecta (OI). The clinical consequences of such mutations range from mild to lethal, with more serious clinical severity associated with larger Gly replacement residues. Here, we investigate the influence of the identity of the residue replacing Gly within and adjacent to the integrin binding 502GFPGER507 sequence on triple-helix structure, stability and integrin binding using a recombinant bacterial collagen system. Recombinant collagens were constructed with Gly substituted by Ala, Ser or Val at four positions within the integrin binding region. All constructs formed a stable triple-helix structure with a small decrease in melting temperature. Trypsin was used to probe local disruption of the triple helix, and Gly to Val replacements made the triple helix trypsin sensitive at three of the four sites. Any mutation at Gly505, eliminated integrin binding, while decreased integrin binding affinity was observed in the replacement of Gly residues at Gly502 following the order Val > Ser > Ala. Molecular dynamics simulations indicated that all Gly replacements led to transient disruption of triple-helix interchain hydrogen bonds in the region of the Gly replacement. These computational and experimental results lend insight into the complex molecular basis of the varying clinical severity of OI.

POCD in patients receiving total knee replacement under deep vs light anesthesia: A randomized controlled trial.

Objectives: Clinical observation, as well as randomized controlled trials, indicated an increasing rate of postoperative cognitive dysfunction (POCD) with increasing depth of general anesthesia. However, the findings are subject to bias due to varying degree of analgesia. In this trial, we compared the rate of POCD between patients receiving light versus high anesthesia while holding analgesia comparable using nerve block. Methods: Elderly patients (≧60 years) receiving elective total knee replacement were randomized to receive the surgery under general anesthesia at BIS 40-50 (LOBIS group) or BIS 55-65 (HIBIS group). The femoral nerve and the sciatic nerve were blocked under ultrasonic guidance in all patients before induction. Cognitive performance was assessed with Montreal cognitive assessment (MoCA) at the baseline and 1d, 3d, and 7d after the surgery. POCD was defined by Z score of >1.96 using cross-reference. The extubation time and recovery time were also compared. Results: A total of 66 patients were randomized; 60 (n = 30 per group) completed trial as the protocol specified. POCD occurred in six patients (20%) in the LOBIS group vs. in one patient (3.3%) in the HIBIS group (Figure 3, p = .04). In all seven cases, the diagnosis of POCD was based on MoCA assessment on 1d after the surgery. Assessment in 3d and 7d after surgery did not reveal POCD in any case. Extubation time was longer in the LOBIS group (12.16 ± 2.58 vs. 5.77 ± 3.01 min in the HIBIS group (p < .001)). The time of comeback of directional ability was 13.47 ± 3.14 and 6.17 ± 3.23 min in the LOBIS and HIBIS groups, respectively (p < .001). Conclusions: In elderly patients receiving a total knee replacement, lighter anesthesia could reduce the rate of POCD with complete analgesia during surgery.

Lichenysin production is improved in codY null Bacillus licheniformis by addition of precursor amino acids.

Lichenysin is categorized into the family of lipopeptide biosurfactants and has a variety of applications in the petroleum industry, bioremediation, pharmaceuticals, and the food industry. Currently, large-scale production is limited due to the low yield. This study found that lichenysin production was repressed by supplementation of extracellular amino acids. The global transcriptional factor CodY was hypothesized to prevent lichenysin biosynthesis under an amino acid-rich condition in Bacillus licheniformis. Thus, the codY null strain was constructed, and lichenysin production was increased by 31.0% to 2356 mg/L with the addition of precursor amino acids, and the lichenysin production efficiency was improved by 42.8% to 98.2 mg/L• h. Correspondingly, the transcription levels of the lichenysin synthetase gene lchAA, and its corresponding regulator genes comA, degQ, and degU, were upregulated. Also, the codY deletion enhanced biosynthesis of lichenysin precursor amino acids (Gln, Ile, Leu, and Val) and reduced the formation of byproducts, acetate, acetoin, and 2,3-butanediol. This study firstly reported that lichenysin biosynthesis was negatively regulated by CodY and lichenysin production could be further improved with the precursor amino acid amendment in the codY null strain.

Untangling the transcription regulatory network of the bacitracin synthase operon in Bacillus licheniformis DW2.

The bacitracin synthetase gene cluster in Bacillus licheniformis DW2 is composed of the bacABC operon encoding a non-ribosomal peptide synthetase and bacT encoding a thioesterase. Although the bacitracin gene cluster has been well studied, little is known about how this gene cluster is regulated. This study provides insight into how the transcription factors Spo0A and AbrB regulate bacitracin biosynthesis. Deletion of spo0A resulted in drastically reduced expression of bacA and bacT, and subsequently bacitracin production. On the other hand, the expression of bacA and bacT increased significantly in B. licheniformis DW2ΔabrB and DW2Δ0AΔabrB compared to the wild-type strain DW2. The bacitracin yields on cell numbers (U/CFU) in DW2ΔabrB and DW2Δ0A/pHY300-0A-sad67 were 17.5% and 14.9% higher than that of the wild-type strain. An electrophoretic mobility shift assay (EMSA) further confirmed that AbrB could directly bind to the promoter regions of bacA and bacT. These results indicate that AbrB acts as a repressor of bacitracin biosynthesis by inhibiting bacA and bacT expression, while Spo0A indirectly promotes bacitracin biosynthesis by repressing abrB expression.

Airflow behavior changes in upper airway caused by different head and neck positions: Comparison by computational fluid dynamics.

The feasibility of computational fluid dynamics (CFD) to evaluate airflow characteristics in different head and neck positions has not been established. This study compared the changes in volume and airflow behavior of the upper airway by CFD simulation to predict the influence of anatomical and physiological airway changes due to different head-neck positions on mechanical ventilation. One awake volunteer with no risk of difficult airway underwent computed tomography in neutral position, extension position (both head and neck extended), and sniffing position (head extended and neck flexed). Three-dimensional airway models of the upper airway were reconstructed. The total volume (V) and narrowest area (Amin) of the airway models were measured. CFD simulation with an Spalart-Allmaras model was performed to characterize airflow behavior in neutral, extension, and sniffing positions of closed-mouth and open-mouth ventilation. The comparison result for V was neutral