The human pre-replication complex is an open complex.

In eukaryotes, DNA replication initiation requires assembly and activation of the minichromosome maintenance (MCM) 2-7 double hexamer (DH) to melt origin DNA strands. However, the mechanism for this initial melting is unknown. Here, we report a 2.59-Å cryo-electron microscopy structure of the human MCM-DH (hMCM-DH), also known as the pre-replication complex. In this structure, the hMCM-DH with a constricted central channel untwists and stretches the DNA strands such that almost a half turn of the bound duplex DNA is distorted with 1 base pair completely separated, generating an initial open structure (IOS) at the hexamer junction. Disturbing the IOS inhibits DH formation and replication initiation. Mapping of hMCM-DH footprints indicates that IOSs are distributed across the genome in large clusters aligning well with initiation zones designed for stochastic origin firing. This work unravels an intrinsic mechanism that couples DH formation with initial DNA melting to license replication initiation in human cells.

Blockade of OX40/OX40L signaling using anti-OX40L alleviates murine lupus nephritis.

Genetic variants of the OX40 ligand (OX40L) locus are associated with the risk of systemic lupus erythematosus (SLE), it is unclear how the OX40L blockade delays the lupus phenotype. Therefore, we examined the effects of an anti-OX40L antibody in MRL/Lpr mice. Next, we investigated the effect of anti-OX40L on immunosuppression in keyhole limpet hemocyanin-immunized C57BL/6J mice. In vitro treatment of anti-OX40L in CD4+ T and B220+ B cells was used to explore the role of OX40L in the pathogenesis of SLE. Anti-OX40L alleviated murine lupus nephritis, accompanied by decreased production of anti-dsDNA and proteinuria, as well as lower frequencies of splenic T helper (Th) 1 and T-follicular helper cells (Tfh). In keyhole limpet hemocyanin-immunized mice, decreased levels of immunoglobulins and plasmablasts were observed in the anti-OX40L group. Anti-OX40L reduced the number and area of germinal centers. Compared with the control IgG group, anti-OX40L downregulated CD4+ T-cell differentiation into Th1 and Tfh cells and upregulated CD4+ T-cell differentiation into regulatory T cells in vitro. Furthermore, anti-OX40L inhibited toll-like receptor 7-mediated differentiation of antibody-secreting cells and antibody production through the regulation of the SPIB-BLIMP1-XBP1 axis in B cells. These results suggest that OX40L is a promising therapeutic target for SLE.

Nicotinic acetylcholine receptor modulator insecticides act on diverse receptor subtypes with distinct subunit compositions.

Insect nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels mainly expressed in the central nervous system of insects. They are the directed targets of many insecticides, including neonicotinoids, which are the most widely used insecticides in the world. However, the development of resistance in pests and the negative impacts on bee pollinators affect the application of insecticides and have created a demand for alternatives. Thus, it is very important to understand the mode of action of these insecticides, which is not fully understood at the molecular level. In this study, we systematically examined the susceptibility of ten Drosophila melanogaster nAChR subunit mutants to eleven insecticides acting on nAChRs. Our results showed that there are several subtypes of nAChRs with distinct subunit compositions that are responsible for the toxicity of different insecticides. At least three of them are the major molecular targets of seven structurally similar neonicotinoids in vivo. Moreover, spinosyns may act exclusively on the α6 homomeric pentamers but not any other nAChRs. Behavioral assays using thermogenetic tools further confirmed the bioassay results and supported the idea that receptor activation rather than inhibition leads to the insecticidal effects of neonicotinoids. The present findings reveal native nAChR subunit interactions with various insecticides and have important implications for the management of resistance and the development of novel insecticides targeting these important ion channels.

A SURF4-to-proteoglycan relay mechanism that mediates the sorting and secretion of a tagged variant of sonic hedgehog.

SignificanceSonic Hedgehog (Shh) is a key signaling molecule that plays important roles in embryonic patterning, cell differentiation, and organ development. Although fundamentally important, the molecular mechanisms that regulate secretion of newly synthesized Shh are still unclear. Our study reveals a role for the cargo receptor, SURF4, in facilitating export of Shh from the endoplasmic reticulum (ER) via a ER export signal. In addition, our study provides evidence suggesting that proteoglycans promote the dissociation of SURF4 from Shh at the Golgi, suggesting a SURF4-to-proteoglycan relay mechanism. These analyses provide insight into an important question in cell biology: how do cargo receptors capture their clients in one compartment, then disengage at their destination?

Electron Transfer Efficiency-Regulated Electrochemiluminescence for Rapid Crystallinity Analysis in Layered Materials.

The electrochemiluminescence (ECL) signal is largely determined by the electron transfer efficiency. Therefore, in the nanomaterial-involved ECL system, the structure-related electron distribution could affect the electron transfer efficiency and further alter the ECL intensity. These features make the design of versatile ECL-based analytical techniques for probing the correlated structure possible. And it is generally accepted that the increased crystallinity of nanomaterials usually leads to a uniform electron distribution, which provides higher conductivity. Therefore, the crystallinity-improved conductivity could facilitate electron transfer, promote the electrochemical activity of support materials, and boost the efficiency of the ECL reaction. In this study, we have demonstrated that the ECL signal of the graphitic carbon nitride reporter was proportional to the crystallinity of layered double hydroxides (LDHs), which meets the supposition well. On the basis of this phenomenon, an ECL-based crystallinity analysis approach has been established using CdAl-LDHs as the model materials. The universality of this proposed technique was further validated by the rapid and accurate crystallinity determination of ZnAl-LDH samples with diverse crystallinities. This work not only contributes an alternative to the X-ray diffraction technique for the rapid screening of crystallinity in layered materials but also opens a new avenue for the design of ECL-based structure analysis techniques toward nanomaterials and even organic materials by involving electron transfer regulation correlation.

Real-Time NMR-Based Drug Discovery to Identify Inhibitors against Fatty Acid Synthesis in Living Cancer Cells.

Abnormal fatty acid metabolism is recognized as a key driver of tumor development and progression. Although numerous inhibitors have been developed to target this pathway, finding drugs with high specificity that do not disrupt normal cellular metabolism remains a formidable challenge. In this paper, we introduced a novel real-time NMR-based drug screening technique that operates within living cells. This technique provides a direct way to putatively identify molecular targets involved in specific metabolic processes, making it a powerful tool for cell-based drug screening. Using 2-13C acetate as a tracer, combined with 3D cell clusters and a bioreactor system, our approach enables real-time detection of inhibitors that target fatty acid metabolism within living cells. As a result, we successfully demonstrated the initial application of this method in the discovery of traditional Chinese medicines that specifically target fatty acid metabolism. Elucidating the mechanisms behind herbal medicines remains challenging due to the complex nature of their compounds and the presence of multiple targets. Remarkably, our findings demonstrate the significant inhibitory effect of P. cocos on fatty acid synthesis within cells, illustrating the potential of this approach in analyzing fatty acid metabolism events and identifying drug candidates that selectively inhibit fatty acid synthesis at the cellular level. Moreover, this systematic approach represents a valuable strategy for discovering the intricate effects of herbal medicine.

Hyperspectral digital holography realized by using an electro-optical frequency comb via injection locking.

Hyperspectral digital holography (HSDH) is a versatile holographic imaging technique that offers large unambiguous depth range and spectroscopic information. In this Letter, we propose a novel, to the best of our knowledge, HSDH system that is realized by using an electro-optical frequency comb (EOFC) via injection locking. In comparison with conventional dual-comb HSDH, the proposed system only requires one EOFC and few other devices, which not only simplifies the system structure and reduces the cost but also improves the imaging speed. We validated the system using an EOFC with 20 optical frequencies spaced at 18 GHz intervals. In a total measurement time of 0.5 s, we successfully captured images of two targets that were 0.74 mm apart without phase ambiguity and obtained the transmission spectrum of an absorbing gas simultaneously. This work provides valuable insights for HSDH systems relying on an optical frequency comb.

Circ-CARD6 inhibits oxidative stress-induced apoptosis and autophagy in ARPE-19 cells via the miR-29b-3p/PRDX6/PI3K/Akt axis.

BACKGROUND: Oxidative stress-induced damage and dysfunction of retinal pigment epithelium (RPE) cells are important pathogenetic factors of age-related macular degeneration (AMD) and hereditary retinopathy diseases (HRDs). This study aimed to elucidate the roles and mechanisms of circ-CARD6 and miR-29b-3p in oxidative stress-induced RPE and provide new ideas for the diagnosis and treatment of retinopathy disease (RD). METHODS: A model of oxidative stress-induced RPE (ARPE-19) was established, and the level of malondialdehyde (MDA) and concentration of reactive oxygen species (ROS) were detected by a DCFH-DA fluorescent probe and MDA kit. The cell viability was measured by a CCK-8 assay. The expression of PRDX6/PI3K/Akt axis genes and proteins related to apoptosis and autophagy were determined by RT‒qPCR and Western blot analyses. The dual-luciferase reporter system confirmed the targeting relationship between miR-29b-3p and circ-CARD6 and between miR-29b-3p and PRDX6. RESULTS: In H2O2-treated ARPE-19 cells, the expression of circ-CARD6 and PRDX6 was decreased, while the expression of miR-29b-3p was increased. The overexpression of circ-CARD6 inhibits oxidative stress-induced increases in ROS, apoptosis and autophagy in ARPE-19 cells. circ-CARD6 targets miR-29b-3p, miR-29b-3p targets PRDX6, and circ-CARD6 regulates PRDX6 via miR-29b-3p. Further studies showed that circ-CARD6 acts as a competitive endogenous RNA of miR-29b-3p to affect the expression of PRDX6, thereby inhibiting autophagy and apoptosis in ARPE-19 cells. CONCLUSION: circ-CARD6 can inhibit oxidative stress and apoptosis by regulating the miR-29b-3p/PRDX6/PI3K/Akt axis.

T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain as a promising immune checkpoint target for the treatment of SLE.

Immune checkpoints (ICs) play a pivotal role in orchestrating immune regulation, crucial for the maintenance of immune tolerance and prevention of autoimmune diseases. One noteworthy example among these immune regulators is T cell immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT). The TIGIT pathway's inhibition or the absence of TIGIT has been linked to the hyperactivation and excessive proliferation of T cells, rendering individuals more susceptible to autoimmune diseases and exacerbating inflammatory responses. Conversely, the activation of TIGIT has exhibited promising outcomes in ameliorating autoimmune disorders, as observed in murine models of systemic lupus erythematosus (SLE). Consequently, a judicious exploration of the co-inhibitory axis appears warranted for the effective management of pathogenic immune responses in SLE. In light of compelling evidence, this review undertakes a comprehensive examination of TIGIT's characteristics within the context of autoimmunity, offering insights into its potential as a therapeutic target for SLE.

A comprehensive investigation on the chemical changes of traditional Chinese medicine with classic processing technology: Polygonum multiflorum under nine cycles of steaming and sunning as a case study.

The processing of traditional Chinese medicine (TCM) plays an important role in the clinical application, which usually has the function of "increasing efficiency and reducing toxicity". Polygonum multiflorum (PM) has been reported to induce hepatotoxicity, while it is believed that the toxicity is reduced after processing. Studies have shown that the hepatotoxicity of PM is closely related to the changes in chemical components before and after processing. However, there is no comprehensive investigation on the chemical changes of PM during the processing progress. In this research, we established a comprehensive method to profile both small molecule compounds and polysaccharides from raw and different processed PM samples. In detail, an online two-dimensional liquid chromatography coupled with quadrupole-orbitrap mass spectrometry (2D-LC/Q-Orbitrap MS) was utilized to investigate the small molecules, and a total of 150 compounds were characterized successfully. After multivariate statistical analysis, 49 differential compounds between raw and processed products were screened out. Furthermore, an accurate and comprehensive method for quantification of differential compounds in PM samples was established based on ultra-high performance liquid chromatography/Q-Orbitrap-MS (UHPLC/Q-Orbitrap-MS) within 16 min. In addition, the changes of polysaccharides in different PM samples were analyzed, and it was found that the addition of black beans and steaming times would affect the content and composition of polysaccharides in PM significantly. Our work provided a reference basis for revealing the scientific connotation of the processing technology and increasing the quality control and safety of PM.

Hydration deactivation mechanism of the 〈100〉 oriented cuprous oxide photocathodes in solar water splitting and the regenerated three-dimensional structure.

Photocorrosion is the most ticklish problem of cuprous oxide (Cu2O), and it is widely assumed that the deactivation of Cu2O photocathodes in solar water splitting is caused by spontaneous oxidation-reduction (REDOX) reactions. However, this work shows that 〈100〉-oriented Cu2O photocathodes undergo a non-REDOX hydration deactivation mechanism. Briefly, water molecules are embedded in the Cu2O crystals at low potential under illumination and produce amorphous CuOH, which can be dehydrated at high potential to heal the Cu-O-Cu bonds and regenerate foamed Cu2O films with a three-dimensional skeleton structure. This study provides a new insight towards the protection and application of Cu2O photocathodes.

Preliminary Study on the Correlation Between Episcleral Venous Pressure and Intraocular Pressure in TAO Patients and Its Clinical Value.

Objective: To study the correlation between episcleral vein pressure (EVP) with intraocular pressure (IOP), exophthalmos, and optic nerve injury in thyroid-associated ophthalmopathy (TAO) patients and to explore the possibility of higher EVP as an intervention indicator in TAO patients. Methods: This study was a case-control study, including the TAO group and normal control group. TAO group: 15 patients (30 eyes) were diagnosed with TAO complicated with exophthalmos. Normal control group: 14 cases, 28 eyes. EVP, IOP, exophthalmos, retinal nerve fiber layer thickness, and visual field were measured, respectively in the two groups. Non-parametric test was used to compare the difference between EVP and IOP between the two groups, test the correlation between EVP and IOP or exophthalmos, and analyze the clinical characteristics of optic nerve injury in patients with elevated IOP in the TAO group. Results: The EVP in the TAO group (15.30±3.48 mmHg) was significantly higher than the normal control group (8.82±1.44 mmHg) (P < .001). The IOP in the TAO group (18.55±8.13 mmHg) was significantly higher than in the normal control group (12.98±2.10 mmHg) (P < .001) (3) There was a positive linear correlation between EVP (X) and IOP (Y) in TAO group: Y = 0.9684x + 3.737 (rs>0, P < .05); There was a positive linear correlation between EVP (Y) and exophthalmos (X) in TAO group: Y = 0.9218x - 2.691 (rs>0, P < .05); Some TAO patients with elevated EVP had the related manifestations of optic nerve function impairment: thinning of retinal nerve fiber layer and loss of visual field. However, there was no clear correlation between EVP and the thickness of the optic nerve fiber layer (P = .4354). Conclusion: The increase of EVP is an important factor leading to elevated IOP in TAO patients, which may be used as an indicator for intervention treatment in TAO patients. EVP can be used to indirectly evaluate orbital pressure. TAO patients can develop secondary glaucoma with irreversible optic nerve damage due to the continuous Elevation of EVP.

Monolithic Interphase Enables Fast Kinetics for High-Performance Sodium-Ion Batteries at Subzero Temperature.

In spite of the competitive performance at room temperature, the development of sodium-ion batteries (SIBs) is still hindered by sluggish electrochemical reaction kinetics and unstable electrode/electrolyte interphase under subzero environments. Herein, a low-concentration electrolyte, consisting of 0.5M NaPF6 dissolving in diethylene glycol dimethyl ether solvent, is proposed for SIBs working at low temperature. Such an electrolyte generates a thin, amorphous, and homogeneous cathode/electrolyte interphase at low temperature. The interphase is monolithic and rich in organic components, reducing the limitation of Na+ migration through inorganic crystals, thereby facilitating the interfacial Na+ dynamics at low temperature. Furthermore, it effectively blocks the unfavorable side reactions between active materials and electrolytes, improving the structural stability. Consequently, Na0.7Li0.03Mg0.03Ni0.27Mn0.6Ti0.07O2//Na and hard carbon//Na cells deliver a high capacity retention of 90.8 % after 900 cycles at 1C, a capacity over 310 mAh g-1 under -30 °C, respectively, showing long-term cycling stability and great rate capability at low temperature.

Noninvasive imaging signatures of HER2 and HR using ADC in invasive breast cancer: repeatability, reproducibility, and association with pathological complete response to neoadjuvant chemotherapy.

BACKGROUND: The immunohistochemical test (IHC) of HER2 and HR can provide prognostic information and treatment guidance for invasive breast cancer patients. We aimed to develop noninvasive image signatures ISHER2 and ISHR of HER2 and HR, respectively. We independently evaluate their repeatability, reproducibility, and association with pathological complete response (pCR) to neoadjuvant chemotherapy. METHODS: Pre-treatment DWI, IHC receptor status HER2/HR, and pCR to neoadjuvant chemotherapy of 222 patients from the multi-institutional ACRIN 6698 trial were retrospectively collected. They were pre-separated for development, independent validation, and test-retest. 1316 image features were extracted from DWI-derived ADC maps within manual tumor segmentations. ISHER2 and ISHR were developed by RIDGE logistic regression using non-redundant and test-retest reproducible features relevant to IHC receptor status. We evaluated their association with pCR using area under receiver operating curve (AUC) and odds ratio (OR) after binarization. Their reproducibility was further evaluated using the test-retest set with intra-class coefficient of correlation (ICC). RESULTS: A 5-feature ISHER2 targeting HER2 was developed (AUC = 0.70, 95% CI 0.59 to 0.82) and validated (AUC = 0.72, 95% CI 0.58 to 0.86) with high perturbation repeatability (ICC = 0.92) and test-retest reproducibility (ICC = 0.83). ISHR was developed using 5 features with higher association with HR during development (AUC = 0.75, 95% CI 0.66 to 0.84) and validation (AUC = 0.74, 95% CI 0.61 to 0.86) and similar repeatability (ICC = 0.91) and reproducibility (ICC = 0.82). Both image signatures showed significant associations with pCR with AUC of 0.65 (95% CI 0.50 to 0.80) for ISHER2 and 0.64 (95% CI 0.50 to 0.78) for ISHER2 in the validation cohort. Patients with high ISHER2 were more likely to achieve pCR to neoadjuvant chemotherapy with validation OR of 4.73 (95% CI 1.64 to 13.65, P value = 0.006). Low ISHR patients had higher pCR with OR = 0.29 (95% CI 0.10 to 0.81, P value = 0.021). Molecular subtypes derived from the image signatures showed comparable pCR prediction values to IHC-based molecular subtypes (P value > 0.05). CONCLUSION: Robust ADC-based image signatures were developed and validated for noninvasive evaluation of IHC receptors HER2 and HR. We also confirmed their value in predicting treatment response to neoadjuvant chemotherapy. Further evaluations in treatment guidance are warranted to fully validate their potential as IHC surrogates.

A novel missense mutation in the CRYBA2 caused autosomal dominant presenile cataract in a Chinese family.

Presenile cataract is a relatively rare type of cataract, but its genetic mechanisms are currently not well understood. The precise identification of these causative genes is crucial for effective genetic counseling for patients and their families. The aim of our study was to identify the causative gene associated with presenile cataract in a Chinese family. In February 2020, a four-generation pedigree of presenile cataract patients was recruited at the 2nd Affiliated Hospital of Kunming Medical University. One patient and her healthy husband from the family underwent whole exome sequencing. The variant was validated through sanger sequencing, and co-segregation analysis was conducted in all family members to assess its pathogenicity. Molecular dynamics simulation (MDS) was used to analyze the conformation of both the wild type and pathogenic mutant loci p.Y153H of CRYBA2. We identified presenile cataract in the pedigree, which follows an autosomal-dominant pattern of inheritance. The family includes five clinically affected patients who all developed presenile cataract between the ages from 24 to 30. We confirmed the pathogenicity of a heterozygous missense variant (NM_057093:c.457T >C) in CRYBA2 within this family. The affected amino acid demonstrates high conservation across species. Subsequent sanger sequencing confirmed co-segregation of the disease in all family members. MDS analysis revealed that the p.Y153H mutant disrupted hydrogen bond formation between Y153 and R193 within the two ß-strands of the fourth Greek key domain, leading to destabilization of the ßA2-crystallin. In conclusion, a novel causative mutation (NM_057093:c.457T>C) in CRYBA2 might contribute to autosomal dominant presenile cataract.

Fecal microbiota transplantation for the management of autoimmune diseases: Potential mechanisms and challenges.

Autoimmune diseases (AIDs) are a series of immune-mediated lethal diseases featured by over-activated immune cells attacking healthy self-tissues and organs due to the loss of immune tolerance, which always causes severe irreversible systematical organ damage and threatens human health heavily. To date, there are still no definitive cures for the treatment of AIDs due to their pathogenesis has not been clearly understood. Besides, the current clinical treatments of AIDs majorly rely on glucocorticoids and immune suppressors, which can lead to serious side effects. In the past years, there are increasing studies demonstrating that an imbalance of gut microbiota is intimately related to the pathogenesis of various AIDs, shedding light on the development of therapeutics by targeting the gut microbiota for the management of AIDs. Among all the approaches targeting the gut microbiota, fecal microbiota transplantation (FMT) has attracted increasing interest, and it has been proposed as a possible strategy to intervene in the homeostasis of gut microbiota for the treatment of various diseases. However, despite the reported good curative effects and clinical studies conducted on FMT, the detailed mechanisms of FMT for the effective treatment of those diseases have not been figured out. To fully understand the mechanisms of the therapeutic effects of FMT on AIDs and improve the therapeutic efficacy of FMT treatment, a systematic review of this topic is necessary. Hence, in this review paper, the potential mechanisms of FMT for the treatment of various AIDs were summarized, including promotion, shaping, activation, or inhibition of the host immune system via the interactions between the microorganisms and the gut immune system, gut-brain, gut-liver, gut-kidney axis, and so on. Then, applications of FMT for the treatment of various AIDs were detailed presented. Finally, the current challenges and potential solutions for the development of FMT formulations and FMT therapeutics were comprehensively discussed.

Scanning-free hybrid Rayleigh-Brillouin distributed fiber-optic sensing system.

Hybrid systems based on Brillouin optical time domain analysis (BOTDA) utilizing Rayleigh backscattering light wave as a probe have enabled single-end and long-range distributed sensing for multiple parameters. However, the spatial resolution for dynamic parameter measurement is limited, and the frequency scanning process of BOTDA is time-consuming. To address these challenges, we propose a hybrid system that combines BOTDA and time-gated digital optical frequency domain reflectometry (TGD-OFDR), aiming to enhance the spatial resolution of dynamic measurements without compromising the system's signal-to-noise ratio and eliminate the frequency scanning process of BOTDA. In the experimental setup, we conducted measurements on a 9.52 km single-mode fiber. A sinusoidal vibration with a frequency of 3 kHz was measured with a spatial resolution of 3 m, achieving a noise floor of 0.05 nε/√Hz. Furthermore, temperature measurements with a spatial resolution of 10 m and a Brillouin frequency shift (BFS) measurement accuracy of 0.74 MHz were successfully obtained using the scanning-free single-end BOTDA technique. This hybrid system shows promising potential for various applications in distributed fiber-optic sensing.

Optical frequency domain reflectometry with broadened frequency sweep range assisted by a dual electro-optic frequency comb.

We propose an optical frequency domain reflectometry (OFDR) with the assistance of a dual electro-optic frequency comb (EOFC), which is intended to improve the system spatial resolution. As the spatial resolution of an OFDR system is inversely proportional to the frequency sweep range, the EOFC acts as a multi-frequency light source for collecting Rayleigh backscattering signals, which are combined to extend the effective frequency sweep range. By utilizing this technique, we have successfully expanded the experimental frequency sweep range to hundreds of gigahertz, achieving a sub-millimeter spatial resolution.

Discovery and characterization of a novel PKD-Fn3 domains containing GH44 endoglucanase from a Tibetan metagenomic library.

AIMS: To explore novel microbial endoglucanases with unique properties derived from extreme environments by using metagenomics approach. METHODS AND RESULTS: A Tibetan soil metagenomic library was applied for screening cellulase-active clones by function-based metagenomics. The candidate genes in the active clones were identified through bioinformatic analyses and heterologously expressed using an Escherichia coli system. The recombinant endoglucanases were purified and characterized using enzyme assays to determine their bioactivities, stabilities, substrate specificities, and other enzymatic properties. A novel endoglucanase gene Zfeg1907 was identified, which consisted of a glycoside hydrolase family 44 (GH44) catalytic domain along with a polycystic kidney disease (PKD) domain and a fibronectin type Ⅲ (Fn3) domain at the C terminal. Recombinant enzyme ZFEG1907 and its truncated mutant ZFEG1907t (ΔPKDΔFn3) were successfully expressed and purified. The two recombinants exhibited catalytic activities toward carboxymethyl cellulose, konjac glucomannan (KGM), and lichenan. Both enzymes had an optimal temperature of 50°C and an optimal pH value of 5.0. The catalytic activities of both recombinant enzymes were promoted by adding Zn2+ and Ca2+ at the final concentration of 10 mM. The Km value of ZFEG1907 was lower, while the kcat/Km value of ZFEG1907 was higher than those of of ZFEG1907t when using carboxymethyl cellulose, KGM, and lichenan as substrates. Structure prediction of two recombinants revealed that PKD-Fn3 domains consisted of a flexible linker and formed a ß-sandwich structure. CONCLUSIONS: A novel endoglucanase ZFEG1907 contained a GH44 catalytic domain and a PKD-Fn3 domain was characterized. The PKD-Fn3 domains were not indispensable for the activity but contributed to the enzyme binding of the polysaccharide substrates as a carbohydrate-binding module (CBM).

Three-Dimensional Digitalized Virtual Planning of Free Anterior Tibial Artery Perforator Flap for Repairing Soft Tissue Defects in Extremities.

BACKGROUND: Traditional research methods have limited the application of anterior tibial artery perforator flap due to incomplete knowledge of the perforator. This study aimed to investigate the feasibility of three-dimensional digitalized virtual planning of free anterior tibial artery perforator flap for repairing soft tissue defects in extremities. METHODS: A total of 11 patients with soft tissue defects in extremities were included. The patient underwent computed tomography angiography (CTA) of bilateral lower limbs, and then the three-dimensional models of bones, arteries, and skin were constructed. Septocutaneous perforators with appropriate length and diameter were selected to design anterior tibial artery perforator flaps in software, and the virtual flaps were superimposed onto the patient's donor site in a translucent state. During the operation, the flaps were dissected and anastomosed to the proximal blood vessel of the defects as designed. RESULTS: Three-dimensional modeling showed clear anatomical relationships between bones, arteries, and skin. The origin, course, location, diameter, and length of the perforator obtained during the operation were consistent with those observed preoperatively. Eleven anterior tibial artery perforator flaps were successfully dissected and transplanted. Postoperative venous crisis occurred in one flap, partial epidermis necrosis occurred in another flap, while the remaining flaps completely survived. One flap was treated with debulking operation. The remaining flaps maintained aesthetic appearance, which did not affect the function of the affected limbs. CONCLUSIONS: Three-dimensional digitalized technology can provide comprehensive information on anterior tibial artery perforators, thus assisting in planning and dissecting patient-specific flaps for repairing soft tissue defects in extremities.