Initial cyclic-di-GMP upregulation triggers sporadic cellular expansion leading to improved cellular survival.

Bacterial second messenger c-di-GMP upregulation is associated with the transition from planktonic to sessile microbial lifestyle, inhibiting cellular motility, and virulence. However, in-depth elucidation of the cellular processes resulting from c-di-GMP upregulation has not been fully explored. Here, we report the role of upregulated cellular c-di-GMP in promoting planktonic cell growth of Escherichia coli K12 and Pseudomonas aeruginosa PAO1. We found a rapid expansion of cellular growth during initial cellular c-di-GMP upregulation, resulting in a larger planktonic bacterial population. The initial increase in c-di-GMP levels promotes bacterial swarming motility during the growth phase, which is subsequently inhibited by the continuous increase of c-di-GMP, and ultimately facilitates the formation of biofilms. We demonstrated that c-di-GMP upregulation triggers key bacterial genes linked to bacterial growth, swarming motility, and biofilm formation. These genes are mainly controlled by the master regulatory genes csgD and csrA. This study provides us a glimpse of the bacterial behavior of evading potential threats through adapting lifestyle changes via c-di-GMP regulation.

Development and validation of a sensitive UPLC-MS/MS analytical method for GFH009 in rat plasma and its application to toxicokinetics studies.

GFH009 is a potent, highly selective, small molecule that targets and inhibits the activity of the CDK9/cyclin T1 regulatory complex of P-TEFb. This study aimed to develop and validate a highly selective and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for precise quantification of GFH009 in rat plasma. This method was subsequently employed for conducting toxicokinetic studies of GFH009 in rats. Plasma was prepared using a simple protein precipitation method by acetonitrile. Chromatographic separation of the analytes was achieved on a BEH C18 analytical column with a rapid 3.0 min run time and a flow rate of 0.5 ml/min. The calibration curves for plasma samples exhibited excellent linearity over a wide concentration range of 1.0-1,000 ng/ml for GFH009. Intra- and inter-day accuracies were within 92.7-105.7%, and precisions were no more than 6.7%. Furthermore, the analyte demonstrated stability under four different storage conditions, with variations of <15.0%. This study pioneers a methodological innovation by introducing a highly reliable, specific and sensitive analytical method for GFH009 in rat plasma. The successful application of this method in toxicokinetic studies further underscores its significance, offering valuable insights for the methodology of clinical pharmacokinetic research.

Enhancing drug-drug Interaction Prediction by Integrating Physiologically-Based Pharmacokinetic Model with Fraction Metabolized by CYP3A4.

BACKGROUND: Enhancing the precision of drug-drug interaction (DDI) prediction is essential for improving drug safety and efficacy. The aim is to identify the most effective fraction metabolized by CY3A4 (fm) for improving DDI prediction using physiologically based pharmacokinetic (PBPK) models. RESEARCH DESIGN AND METHODS: The fm values were determined for 33 approved drugs using a human liver microsome for in vitro measurements and the ADMET Predictor software for in silico predictions. Subsequently, these fm values were integrated into PBPK models using the GastroPlus platform. The PBPK models, combined with a ketoconazole model, were utilized to predict AUCR (AUCcombo with ketoconazole/AUCdosing alone), and the accuracy of these predictions was evaluated by comparison with observed AUCR. RESULTS: The integration of in vitro fm method demonstrates superior performance compared to the in silico fm method and fm of 100% method. Under the Guest-limits criteria, the integration of in vitro fm achieves an accuracy of 76%, while the in silico fm and fm of 100% methods achieve accuracies of 67% and 58%, respectively. CONCLUSIONS: Our study highlights the importance of in vitro fm data to improve the accuracy of predicting DDIs and demonstrates the promising potential of in silico fm in predicting DDIs.

Aquiflexum gelatinilyticum sp. nov., isolated from river water.

Two Gram-stain-negative, strictly aerobic, rod-shaped, non-motile and non-gliding bacteria, designated as XJ19-10T and XJ19-11, were isolated from river water in Xinjiang Uygur Autonomous Region, PR China. Cells of these strains were catalase-, oxidase- and gelatinase-positive and contained carotenoids but no flexirubins. Growth occurred at 10-30 °C, pH 7.0-9.0 and with 0-2.5% (w/v) NaCl. On the basis of the results of 16S rRNA gene sequence and genome analyses, the two isolates represented members of the genus Aquiflexum, and the closest relative was Aquiflexum aquatile Z0201T with 16S rRNA gene sequence pairwise similarities of 97.9-98.1%. Furthermore, the average nucleotide identities and digital DNA-DNA hybridization identities between the two isolates and other relatives were all less than 82.9 and 28.2 %, respectively, all below the species delineation thresholds. The results of pan-genomic analysis indicated that the type strain XJ19-10T shared 2813 core gene clusters with other three type strains of members of the genus Aquiflexum, as well as having 623 strain-specific clusters. The major polar lipids were phosphatidylethanolamine, phosphatidylcholine, an unidentified aminolipid and unidentified lipids. The predominant fatty acids (>10% of the total contents) were iso-C15 : 0, iso-C15 : 1G, iso-C17 : 0 3-OH and summed feature 9, and MK-7 was the respiratory quinone. On the basis of the results of phenotypic, physiological, chemotaxonomic and genotypic characterization, strains XJ19-10T and XJ19-11 are considered to represent a novel species, for which the name Aquiflexum gelatinilyticum sp. nov. is proposed. The type strain is XJ19-10T (=CGMCC 1.19385T =KCTC 92266T).

Parapedobacter tibetensis sp. nov., isolated from shore soil of saline lake in Tibet of China and its genome mining of secondary metabolite.

Five aerobic, Gram-stain-negative, non-motile, non-spore-forming, short rod bacteria strains, designated as C3-1-R+6T, C3-2-M9, B3-2-R-7, B3-2-R-21 and C3-2-M2, were isolated from shore soil of LungmuCo Lake in Tibet of China. The 16S rRNA gene sequence comparisons confirmed their affiliation to the genus Parapedobacter of the family Sphingobacteriaceae, and showed that they were most closely related to Parapedobacter lycopersici KACC 18788T with 94.26 % similarities. The average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values between them and the validly published Parapedobacter species were all below the thresholds for delineating species, supporting that they were novel species of genus Parapedobacter. The ANI, AAI and dDDH values between strains C3-1-R+6T and Parapedobacter lycopersici KACC 18788T were 72, 75, and 18% respectively. Meanwhile, the ANI/AAI and dDDH values between these five isolates were higher than the threshold values, showing that they belonged to the same species of Parapedobacter. According to genome comparison, the novel isolates have some special biosynthetic gene clusters of secondary metabolites including bacteriton, aryl-polyene, lantipeptide and t1pks, which were absent from their most related phylogenetic neighbours P. lycopersici KACC 18788T and P. pyrenivorans CGMCC 1.12195T. The main polar lipids contained phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid, one unidentified glycolipid and five unidentified lipids. The predominant respiratory quinone was MK-7. The major cellular fatty acids were iso-C15 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and iso-C17 : 0 3-OH. The genome size of strain C3-1-R+6T was 5 984 948 bp, and its genomic DNA G+C content was 46.21 mol%. To sum up, the five strains were identified as a novel species of the genus Parapedobacter, for which the name Parapedobacter tibetensis sp. nov. was proposed. The type strain was C3-1-R+6T (=CGMCC 1.19194T=KCTC 92150T).

Flavobacterium frigoritolerans sp. nov. and Flavobacterium shii sp. nov., isolated from glaciers on the Tibetan Plateau.

The genus Flavobacterium belongs to the family Flavobacteriaceae and its members are widely distributed in the environment. Taxonomic descriptions of strains LS1R47T and LS1R49T isolated from the Laigu glacier on the Tibetan Plateau, China, are presented in this study. Both strains were psychrotolerant, Gram-stain-negative, aerobic and rod-shaped. The comparative analysis of 16S rRNA gene sequences showed that strain LS1R47T was closest to Flavobacterium bizetiae CIP 105534T (98.90 %) and strain LS1R49T was closest to Flavobacterium collinsii 983-08T (98.73 %). The 16S rRNA gene sequence similarity, average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two novel isolates were 99.4, 86.0 and 30.9 %, respectively. The ANI and dDDH values between strains LS1R47T and LS1R49T and their closely relatives were below 87.6 and 33.3 %, respectively. Phylogenomic analysis showed that the two strains cluster together with Flavobacterium hydatis ATCC 29551T. Both strains contained MK-6 as sole quinone, phosphatidylethanolamine as the principal polar lipid, and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c), iso-C15 : 0 3-OH, C15 : 0 3-OH and iso-C17 : 0 3-OH as the main fatty acids. These results indicated that strains LS1R47T and LS1R49T represented two novel species within the genus Flavobacterium. Therefore, we propose two novel species, Flavobacterium frigoritolerans sp. nov. (LS1R47T=CGMCC 1.11577T=NBRC 113654T) and Flavobacterium shii sp. nov. (LS1R49T=CGMCC 1.11581T=NBRC 113652T).

Rectangular-Phase Tellurene on Ni(111) from Monolayer Films to Periodic Striped Patterns.

As an emerging member of monoelemental two-dimensional (2D) materials, 2D tellurium (tellurene) has recently attracted intensive attention due to its polymorphism arising from the multivalent nature and fascinating properties such as wide-range band gaps, high carrier mobilities, etc. Herein, we predict the formation of a rectangular-phase tellurene on Ni(111) by first-principles density functional theory (DFT) calculations and realize its direct syntheses and characterizations by molecular beam epitaxy (MBE) and scanning tunneling microscopy (STM). We reveal that the monolayer rectangular tellurene and underlying Ni(111) substrate are strongly coupled, along with good lattice registry along two mutually perpendicular directions, which serves as the key driving force for the tellurene formation. We also uncover the unique morphological transitions of Te/Ni(111) from rectangular tellurene monolayer, to uniform periodic striped patterns at the second layer, and then to thick striped patterns. This work should offer valuable insights for the substrate-mediated syntheses of monoelemental 2D materials, thus propelling their phase engineering and intriguing property explorations.

Death-associated protein kinase 1 is associated with cognitive dysfunction in major depressive disorder.

We previously showed that death-associated protein kinase 1 (DAPK1) expression is increased in hippocampal tissue in a mouse model of major depressive disorde and is related to cognitive dysfunction in Alzheimer's disease. In addition, depression is a risk factor for developing Alzheimer's disease, as well as an early clinical manifestation of Alzheimer's disease. Meanwhile, cognitive dysfunction is a distinctive feature of major depressive disorder. Therefore, DAPK1 may be related to cognitive dysfunction in major depressive disorder. In this study, we established a mouse model of major depressive disorder by housing mice individually and exposing them to chronic, mild, unpredictable stressors. We found that DAPK1 and tau protein levels were increased in the hippocampal CA3 area, and tau was hyperphosphorylated at Thr231, Ser262, and Ser396 in these mice. Furthermore, DAPK1 shifted from axonal expression to overexpression on the cell membrane. Exercise and treatment with the antidepressant drug citalopram decreased DAPK1 expression and tau protein phosphorylation in hippocampal tissue and improved both depressive symptoms and cognitive dysfunction. These results indicate that DAPK1 may be a potential reason and therapeutic target of cognitive dysfunction in major depressive disorder.

Ophthalmic Solution of Smart Supramolecular Peptides to Capture Semaphorin 4D against Diabetic Retinopathy.

Diabetic retinopathy (DR) is the leading cause of vision loss in working age population. Intravitreal injection of anti-VEGF antibody is widely used in clinical practice. However, about 27% of patients show poor response to anti-VEGF therapy and about 50% of these patients continue to have macular thickening. Frequent intravitreal injections of antibody may increase the chance of endophthalmitis and cause visual loss or even blindness once happened. Therefore, there is a greatly urgent need for novel noninvasive target to treat DR clinically. Here, the formulation of a smart supramolecular peptide (SSP) eye drop for DR treatment that is effective via specifically identifying and capturing soluble semaphorin 4D (sSema4D), a strongly pro-angiogenesis and exudates factor, is reported. The SSP nanostructures encapsulate sSema4D so that all biological effects mediated by three receptors of sSema4D are inhibited, thereby significantly alleviating pathological retinal angiogenesis and exudates in DR. Moreover, it is found that combination of SSPs eye drop and anti-VEGF injection shows better therapeutic effect over anti-VEGF treatment alone. Overall, SSP eye drop provide an alternative and effective method for noninvasive treatment for DR.

Inhibition of UGT1A1*1 and UGT1A1*6 catalyzed glucuronidation of SN-38 by silybins.

UGT1A1 is the main enzyme that catalyzes the metabolic elimination and detoxification of SN-38, the active form of the drug irinotecan. Milk thistle products have been used widely to protect the liver from injury associated with the use of chemotherapeutic agents. To evaluate whether SN-38 metabolism can be affected by milk thistle products, the inhibitory effects of silybins on UGT1A1*1 and UGT1A1*6 were evaluated in the present investigation. Both silybin A and silybin B potently inhibited SN-38 glucuronidation catalyzed by UGT1A1*1 or UGT1A1*6. It was noteworthy that silybin A and silybin B showed synergistic effect in UGT1A1*1 microsomes at concentration around IC50, while additive effect in UGT1A1*6. According to the predicted AUCi/AUC ratios (the ratio of the area under the plasma concentration-time curve of SN-38 in the presence and absence of silybins), the coadministration of irinotecan and several milk thistle products, including silybin-phosphatidylcholine complex, two Legalon capsules, four Silymarin tablets or four Liverman capsules, may lead to clinically significant herb-drug interactions (HDI) via UGT1A1 inhibition. Meanwhile, Rgut values were much higher than 11 in all the groups, indicating potential HDI due to intestinal UGT1A1 inhibition.

Power equalization method of a DFB fiber laser sensor array.

To reduce the output power ununiformity mainly caused by the exponential attenuation of pump power in a distributed feedback fiber laser (DFB FL) sensor array, a power equalization method based on array structure optimization is proposed. By analyzing the influencing factors of the output power flatness of the array, an output power prediction model of a DFB FL wavelength division multiplexing (WDM) array is established, and the standard deviation coefficient of the output power is proposed as the main evaluating indicator for assessing the output power flatness. An array structure optimization scheme based on the simulated annealing algorithm is designed, and the optimized array structure of the 64-element DFB FL sensor array is achieved. The results show that the power fluctuation of the optimized array is significantly reduced from universal 5-10 dB to smaller than 2.6 dB, while the performance of the DFB FL sensor array is improved with better noise floor and increased multiplexing capacity, as well as improved array design efficiency.

A painless and flexible bi-directional blood glucose-regulating system inspired by an inverter air conditioner.

Pursuing painless and flexible blood glucose regulation has been a century-long arduous mission. The current therapeutic systems can only regulate blood glucose unidirectionally (reduce), and the adjustment range is large, which is prone to the risk of hypoglycemia. Herein, inspired by the temperature fluctuation range controlled by the inverter air conditioner, we report a new bi-directional blood glucose-regulating drug delivery system (BDRS) consisting of glucose-loaded pressure-responsive nano-vesicles (Glu@PRNV), insulin-loaded black phosphorus nanosheets (Insulin@BPNs), hydrogel, and a painless blood sugar monitor patch. At first, BDRS could monitor blood glucose in real-time through visible color changes. Afterward, according to different requirements, BDRS could release glucose with the guidance of external pressure, or supplement insulin under near-infrared (NIR) irradiation, through which, the blood glucose level of diabetics could be accurately accommodated within a reasonable fluctuation range, thus minifying the likelihood of sudden hyperglycemia or hypoglycemia. Collectively, the supply-demand balance of blood glucose could be maintained via this real-time bi-directional drug delivery system, thereby improving the quality of life of diabetics. We have also verified the universality of this technique through a similar bi-directional sleep regulation.

Mechanism-Based Pharmacokinetic Model for the Deglycosylation Kinetics of 20(S)-Ginsenosides Rh2.

Aim: The 20(S)-ginsenoside Rh2 (Rh2) is being developed as a new antitumor drug. However, to date, little is known about the kinetics of its deglycosylation metabolite (protopanoxadiol) (PPD) following Rh2 administration. The aim of this work was to 1) simultaneously characterise the pharmacokinetics of Rh2 and PPD following intravenous and oral Rh2 administration, 2) develop and validate a mechanism-based pharmacokinetic model to describe the deglycosylation kinetics and 3) predict the percentage of Rh2 entering the systemic circulation in PPD form. Methods: Plasma samples were collected from rats after the I.V. or P.O. administration of Rh2. The plasma Rh2 and PPD concentrations were determined using HPLC-MS. The transformation from Rh2 to PPD, its absorption, and elimination were integrated into the mechanism based pharmacokinetic model to describe the pharmacokinetics of Rh2 and PPD simultaneously at 10 mg/kg. The concentration data collected following a 20 mg/kg dose of Rh2 was used for model validation. Results: Following Rh2 administration, PPD exhibited high exposure and atypical double peaks. The model described the abnormal kinetics well and was further validated using external data. A total of 11% of the administered Rh2 was predicted to be transformed into PPD and enter the systemic circulation after I.V. administration, and a total of 20% of Rh2 was predicted to be absorbed into the systemic circulation in PPD form after P.O. administration of Rh2. Conclusion: The developed model provides a useful tool to quantitatively study the deglycosylation kinetics of Rh2 and thus, provides a valuable resource for future pharmacokinetic studies of glycosides with similar deglycosylation metabolism.

[Research Progress of Fibroblast Growth Factor 8's Role in the Regulation of Bone Development and Homeostasis].

The proper development and the homeostasis maintenance of bones are important prerequisites for the normal functioning of the human body. Bone developmental deformities or homeostasis disorders, such as Kashin-Beck disease, craniosynostosis, cleft palate and osteoarthritis, severely affect the life of patients, causing significant stress to the family and the society. Fibroblast growth factor 8 (FGF8) plays multiple functions through the course of the life of organisms. Abnormal expression of FGF8 may cause disorders of bone homeostasis and developmental abnormalities of bones. More and more studies have found that FGF8 may play an important role in bone development and may become a potential therapeutic target. Herein, we reviewed the role of FGF8 in a variety of skeletal abnormalities, intending to provide new perspectives for the prevention and treatment of related diseases in the future.

Mucilaginibacter aurantiaciroseus sp. nov. and Mucilaginibacter flavidus sp. nov., isolated from Renlongba glacier on the Tibetan Plateau.

Strains RB4R14T and RT5R15T, two Gram-stain-negative, aerobic, rod-shaped, non-motile bacteria, were isolated from ice and cryoconite of Renlongba glacier, respectively, on the Tibetan Plateau, PR China. The results of phylogenetic analysis based on 16S rRNA genes indicated that strains RB4R14T and RT5R15T belonged to the genus Mucilaginibacter with the highest similarities to Mucilaginibacter rigui WPCB133T (98.78 %) and Mucilaginibacter xinganensis BJC16-A31T (97.64 %), respectively. The genomic DNA G+C contents of strains RB4R14T and RT5R15T were 42.8 and 43.1 mol%, respectively. The digital DNA-DNA hybridization values between strains RB4R14T, RT5R15T and their close relatives were below 31.9 and 17.4 %, respectively. The average nucleotide identity values between the two novel strains and their close relatives were 79.5-82.0 and 77.9-79.3 % respectively, indicating the novelty of the two isolates at a species level. The two novel strains contained MK-7 as the major menaquinone, and summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c), iso-C15 : 0 and iso-C17 : 0-3OH as the major fatty acids. The major polar lipid of the two novel strains were phosphatidylethanolamine. Based on phenotypic, chemotaxonomic and phylogenetic results, we propose two novel species, Mucilaginibacter aurantiaciroseus sp. nov. (RB4R14T=CGMCC 1.11911T=NBRC 114020T) and Mucilaginibacter flavidus sp. nov. (RT5R15T=CGMCC 1.23117T=NBRC 113930T).

Devosia ureilytica sp. nov., isolated from Kuche River in China.

Two novel strains, designated XJ19-45T and XJ19-1, were isolated from water of Kuche River in Xinjiang Uygur Autonomous Region, China. Their cells were Gram-stain-negative, aerobic and motile rods. The phylogenetic analyses based on 16S rRNA genes and genomes showed that the two isolates belonged to the genus Devosia and the closest relative was Devosia subaequoris HST3-14T. The 16S rRNA genes sequences pairwise similarities, average nucleotide identities, digital DNA-DNA hybridizations and average amino acid identities between type strain XJ19-45T and other relatives were all less than 98.3, 80.3, 23.6 and 85.7 %, respectively, all below the species delineation thresholds. Pan-genomic analysis indicated that the novel isolate XJ19-45T shared 1594 core gene clusters with the 11 closely related type strains in Devosia, and the number of strain-specific clusters was 390. The major cellular fatty acids (>10 %) of the two isolates were summed feature 8, C18 : 1 ω7c 11-methyl and C16 : 0. Diphosphatidylglycerol, phosphatidylglycerol and glycolipids were the major polar lipids, and Q10 was the detected respiratory quinone. Based on the results of phenotypic, physiological, chemotaxonomic and genotypic characterizations, we propose that the isolates represent a novel species, for which the name Devosia ureilytica sp. nov. is proposed. The type strain is XJ19-45T (=CGMCC 1.19388T=KCTC 92263T).

Arthrobacter cheniae and Arthrobacter frigidicola sp. nov., isolated from a glacier.

Two Gram-stain-positive, aerobic, rod-shaped, pink and light pink colony-forming bacteria, designated as Hz2T and MDT2-14T, respectively, were isolated from glacier cryoconite samples. Comparisons based on 16S rRNA gene sequences showed that strains Hz2T and MDT2-14T take Arthrobacter bussei KR32T and Arthrobacter zhaoguopingii J391T as their closest neighbours, respectively. The average nucleotide identity values between the two novel strains and their closest relatives were 83.56 and 93.06 %, respectively. The two strains contain MK-9(H2) as their predominant menaquinone. The polar lipids of both strains were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and an unidentified glycolipid. The major fatty acids of strain Hz2T were anteiso-C15 : 0, summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c) and iso-C15 : 0, while the major fatty acids of strain MDT2-14T were anteiso-C15 : 0 and anteiso-C17 : 0. Based on these data, we propose two novel species, Arthrobacter cheniae sp. nov. (Hz2T = CGMCC 1.9262T=NBRC 113086T) and Arthrobacter frigidicola sp. nov. (MDT2-14T=CGMCC 1.9882T=NBRC 113089T).