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A thermostable alanine racemase from Thermoanaerobacter tengcongensis MB4 was successfully expressed in Escherichia coli and characterized. The full-length gene MBalr2 (1164 bp) encodes 388 amino acid residues including 6 out of 8 highly conserved amino acid residues at the entryway to the active site of alanine racemase. Recombinant MBAlr2 and three mutants (S171A, H359Y and double mutation S171A/H359Y) of MBAlr2 were purified by His 6 -tag affinity column and gel filtration chromatography. The purified protein MBAlr2 was a dimeric PLP-dependent enzyme with broad substrate specificity. The optimal racemization temperature and pH were 70–75 °C and 11.0, respectively. The kinetic parameters K m and V max of MBAlr2 at 70 °C, determined by HPLC, were 20.16 mM and 1414 μmol min −1 for l -alanine, and 9.95 mM and 702.6 μmol min −1 for d -alanine, respectively. Enzymatic assays showed that the activity of both mutants (S171A and H359Y) was lost, but the activity of mutant S171A/H359Y was recovered to 69.8 % of wild type, which suggested that residues Ser171 and His359 might be the important residues for catalytic mechanisms of MBAlr2.

Lactic acid has been identified as one of the top 30 potential building-block chemicals from biomass. Therefore, the search for cheap raw materials is an objective to reduce the production costs. Efficient polymer-grade L-lactic acid production was achieved in this report by a thermophilic strain Bacillus sp. XZL4 using corn stover hydrolyzate as sole carbon source. High L-lactic acid concentration (81.0 g L -1 ) was obtained from 162.5 g L -1 concentrated corn stover hydrolyzate (total reducing sugar of 83.0 g L -1 ) with a volumetric productivity of 1.86 g L -1 h -1 (0–36 h) and a product yield of 0.98 g g -1 total reducing sugars. This is the highest L-lactic acid concentration and yield reported from corn stover hydrolyzate. And the high optical purity of L-lactic acid obtained in this study also indicated that Bacillus sp. XZL4 is a promising polymer-grade L-lactic-acid producer from cellulosic biomass.

Osteoporosis is a metabolic bone disease characterized by dysregulated osteoclast activity, resulting in increased bone degradation and compromised bone microarchitecture. While the interconnection between osteoclast differentiation and cellular energy metabolism has become increasingly recognized, the role of pyrimidine metabolism in this process remains largely undefined. Integrative multi-omics analyses were performed to characterize transcriptional and metabolic alterations during receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. The effects of uridine (UD) on osteoclast development and resorptive function were assessed in vitro using RAW264.7 cells and bone marrow-derived macrophages (BMMs). In vivo effects of UD on bone loss were evaluated in an ovariectomized (OVX) mouse model. Integrative analyses revealed distinct metabolic remodeling during osteoclast differentiation and identified UD as a pivotal metabolite that showed a significant decline upon RANKL stimulation. Experimental evidence indicated that exogenous UD supplementation significantly suppressed osteoclast development and resorptive function, along with a reduction in the expression of nuclear factor of activated T cells c1 (NFATc1) and cathepsin K (CTSK). In OVX mice, UD administration improved trabecular microarchitecture, reduced osteoclast burden, and mitigated bone loss. Mechanistically, UD inhibited phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) phosphorylation, facilitated Forkhead box O (FoxO) nuclear translocation, and suppressed reactive oxygen species (ROS) accumulation, thereby preventing NFATc1 activation and nuclear import. Collectively, this research identifies a novel metabolic-signaling interplay linking pyrimidine metabolism with osteoclast differentiation and highlights UD as a promising metabolic regulator for the treatment and prevention of osteoporosis.

In modern society, subarachnoid hemorrhage, mostly caused by intracranial aneurysm rupture, is accompanied by high disability and mortality rate, which has become a major threat to human health. Till now, the etiology of intracranial aneurysm has not been entirely clarified. In recent years, more and more studies focus on the relationship between hemodynamics and intracranial aneurysm. Under the physiological condition, the mechanical force produced by the stable blood flow in the blood vessels keeps balance with the structure of the blood vessels. When the blood vessels are stimulated by the continuous abnormal blood flow, the functional structure of the blood vessels changes, which becomes the pathophysiological basis of the inflammation and atherosclerosis of the blood vessels and further promotes the occurrence and development of the intracranial aneurysm. This review will focus on the relationship between hemodynamics and intracranial aneurysms, will discuss the mechanism of occurrence and development of intracranial aneurysms, and will provide a new perspective for the research and treatment of intracranial aneurysms.

According to the properties of Fourier transform, Fourier single-pixel imaging uses the illumination lights with cosine distributions to obtain the Fourier spectrum of the object, and then apply the inverse Fourier transform to reconstruct the spatial information of the object. This technique does not require detector arrays, such as charge coupled device and has proven to be insensitive to distortion, which is a great improvement over traditional photography techniques. In this manuscript, we present a detailed analysis and discussion on the signal-to-noise ratio (SNR) of Fourier single-pixel imaging. Compared with conventional imaging whose SNR is independent of pixel number N , Fourier single-pixel imaging achieves an improved SNR which is up to N times as high as the dynamic range of detection. Furthermore, this SNR benefit is further confirmed experimentally, in cases of one dimension and two dimensions.

Current surgical procedures for spinal cord tumors lack in vivo high‐resolution multifunctional imaging systems, hindering precise tumor resection. This study introduces the fast adaptive focus tracking robotic optical coherence tomography (FACT‐ROCT) system, which provides real‐time, artifact‐free imaging during surgery, addressing motion artifacts and resolution degradation. Imaging occurs in 22 patients, including 13 with gliomas (WHO grade I‐IV). This represents the first in situ OCT imaging of human spinal cord tumors, enabling the differentiation of tumor types in real‐time. The standard deviation of the attenuation coefficient serves as a physical marker, achieving 90.2%  ±  2.7% accuracy in distinguishing high‐ from low‐grade gliomas intraoperatively at a threshold of 0.75  ±  0.01 mm−1. FACT‐ROCT also enables microvascular imaging, covering areas of 70 mm × 13 mm × 10 mm within 2 min and revealing greater vascular tortuosity in higher‐grade tumors. This extensive imaging capability provides critical information that guides surgical strategies, enhancing surgical outcomes. Overall, FACT‐ROCT represents a significant advancement in intraoperative imaging, offering high‐resolution, high‐speed, and comprehensive insights into spinal cord tumor structure and vasculature. The fast adaptive focus tracking robotic optical coherence tomography (FACT‐ROCT) offers real‐time, high‐resolution imaging of spinal cord tumors during surgery. By reducing motion artifacts with robotics and adaptive focal tracking, it accurately differentiates tumor grades using a novel attenuation coefficient marker and reveals critical microvascular details. FACT‐ROCT represents a major advancement in intraoperative spinal cord imaging techniques.

Pathological features are the gold standard for tumor diagnosis, guiding treatment and prognosis. However, the standard histopathological process is labor-intensive and time-consuming. Although frozen sections offer a quicker alternative, they often induce severe artifacts and suffer from lower accuracy. Dynamic full-field optical coherence tomography (D-FFOCT) is an innovative optical imaging technique that provides rapid histological information by utilizing subcellular dynamics as an intrinsic source of contrast. Despite its advantages, D-FFOCT images of adjacent tissues frequently exhibit abrupt shifts in hue and brightness, which is confusing for pathologists and diminishes its interpretability and reliability. Here, we present an active phase modulation-assisted D-FFOCT (APMD-FFOCT) to improve the imaging stability and achieve continuity and consistency in image stitching, which also enhances the image contrast of tissues with low metabolic dynamics. This enables us to further employ an unsupervised generative adversarial network to convert APMD-FFOCT images into virtual hematoxylin and eosin (H&E) stained images for the first time. Three-dimensional (3D) virtual H&E-stained images can be obtained at a scanning rate of 1 frame per second. Furthermore, we also demonstrate that this novel technique has been successfully applied in cancer diagnosis for the human central nervous system and breast, which proves that this new method will play a new unique and important role in intraoperative histology.

Abstract Pathological features are the gold standard for tumor diagnosis, guiding treatment and prognosis. However, the standard histopathological process is labor-intensive and time-consuming. Although frozen sections offer a quicker alternative, they often induce severe artifacts and suffer from lower accuracy. Dynamic full-field optical coherence tomography (D-FFOCT) is an innovative optical imaging technique that provides rapid histological information by utilizing subcellular dynamics as an intrinsic source of contrast. Despite its advantages, D-FFOCT images of adjacent tissues frequently exhibit abrupt shifts in hue and brightness, which is confusing for pathologists and diminishes its interpretability and reliability. Here, we present an active phase modulation-assisted D-FFOCT (APMD-FFOCT) to improve the imaging stability and achieve continuity and consistency in image stitching, which also enhances the image contrast of tissues with low metabolic dynamics. This enables us to further employ an unsupervised generative adversarial network to convert APMD-FFOCT images into virtual hematoxylin and eosin (H&E) stained images for the first time. Three-dimensional (3D) virtual H&E-stained images can be obtained at a scanning rate of 1 frame per second. Furthermore, we also demonstrate that this novel technique has been successfully applied in cancer diagnosis for the human central nervous system and breast, which proves that this new method will play a new unique and important role in intraoperative histology.

Fast Adaptive Focus Tracking Robotic Optical Coherence Tomography System The cover illustrates the fast adaptive focus tracking robotic optical coherence tomography (FACT‐ROCT) system providing real‐time, high‐resolution imaging during spinal cord tumor surgery. The robotic‐guided OCT probe scans over the surgical site, while the display reveals vascular and structural tumor features. This system enables intraoperative tumor grading and microvascular mapping, enhancing surgical precision and safety. More details can be found in article number 2503566 by Guihuai Wang, Ping Xue, and co‐workers.

Silica/polydopamine/silver (SiO2/PD/Ag) nanoparticles (NPs) with a core–shell–satellite structure were fabricated and the mechanisms of their antibacterial activity were investigated. In this reported work, the results of the reactive oxygen species (ROS) assays, the deoxyribonucleic acid (DNA) damage assays and a cell morphology observation confirmed that Vibrio natriegens, a gram negative bacterium and Bacillus subtilis, a gram positive bacterium could be inhibited by the NPs. Gram negative bacteria exhibited more sensitivity towards the Ag NPs because these NPs were associated with penetration into the cytoplasm, with the subsequent local interaction of Ag with the cell components; thus, causing damages to the cells. SiO2/PD/Ag NPs produced ROS which caused damage to the DNA leading to the suppression of transcription as detected by a reporter gene assay. Furthermore, ROS induced membrane damage was determined by transmission electron microscopy. Thus, the mechanisms of antibacterial activity were interpreted more precisely by using the aforementioned experiments. The results revealed that the production of ROS and damage to the membrane were the two major mechanisms of the bactericidal action of SiO2/PD/Ag NPs; thus, these NPs could be employed as effective antifouling agents.