Olfactory receptors (ORs) form the largest superfamily of G protein-coupled receptors (GPCRs). Traditionally recognized for their role in the nasal olfactory epithelium, where they mediate the sense of smell, accumulating evidence has firmly established their ectopic expression in non-olfactory tissues, including the intestine, lungs, and kidneys. The intestine, as the primary site for nutrient digestion and absorption, harbors a highly complex chemical environment. To adapt to this environment, the gut employs a sophisticated network of “chemosensors” to monitor luminal contents and maintain homeostasis. Among these sensors, intestinal ORs have emerged as crucial functional components, serving as a molecular bridge that connects environmental chemical signals—such as food-derived odorants—to specific physiological responses. This discovery has significantly deepened our understanding of how dietary flavors and compounds influence intestinal physiology at the molecular level. This review systematically summarizes the expression profiles, ligand classification, and biological functions of ORs within the gastrointestinal tract. Studies indicate that intestinal ORs exhibit distinct spatial distribution patterns across different gut segments and display cell-type specificity, particularly within enterocytes and enteroendocrine cells. These receptors function as versatile sensors capable of recognizing a wide variety of ligands, including exogenous dietary components, gut microbiota metabolites such as short-chain fatty acids, and endogenous small molecules like azelaic acid. Upon activation by specific ligands, intestinal ORs trigger intracellular signaling cascades, primarily involving the AC-cAMP-PKA pathway or calcium influx channels. A major focus of this review is to elucidate the molecular mechanisms by which these receptors regulate the secretion of gut hormones. Activation of specific ORs in enteroendocrine cells has been shown to stimulate the release of hormones such as glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and serotonin (5-HT), thereby modulating systemic energy metabolism, glucose homeostasis, and gastrointestinal motility. Furthermore, the review addresses the critical roles of ORs in immune regulation and pathology. Evidence suggests that specific ORs contribute to the maintenance of intestinal immune homeostasis and may offer protection against inflammation. Beyond their involvement in inflammatory responses, ORs such as Olfr78 have been shown to regulate the differentiation and function of intestinal endocrine cells. Similarly, Olfr544 has been demonstrated to alleviate intestinal inflammation by remodeling the gut microbiome and metabolome. These findings collectively suggest that specific ORs hold promise as therapeutic targets for mitigating intestinal inflammation and maintaining gut homeostasis. Additionally, the review explores the emerging role of ORs in cancer. Although OR expression is often downregulated in tumor tissues compared to normal mucosa, activation of specific ORs by certain ligands can inhibit tumor cell proliferation and migration and induce apoptosis via pathways such as MEK/ERK and p38 MAPK. Conversely, other receptors, such as OR7C1, may serve as biomarkers for cancer-initiating cells. In conclusion, intestinal ORs represent a vital component of the gut’s sensory network. The review also discusses the translational potential of these findings. By elucidating the precise pairing relationships between dietary components and specific ORs, novel therapeutic strategies could be developed. Intestinal ORs may thus emerge as promising targets for nutritional and pharmacological interventions in metabolic diseases, inflammatory bowel diseases, and malignancies.

Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe²⁺), whereas clMagR favors ferric iron (Fe³⁺) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe²⁺-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe²⁺/Fe³⁺ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.

Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe²⁺), whereas clMagR favors ferric iron (Fe³⁺) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe²⁺-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe²⁺/Fe³⁺ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.

Objective:To evaluate the association between body mass index (BMI) and bone mineral density of calcaneus in adults.Methods:Data of the second resurvey of China Kadoorie Biobank study from Tongxiang of Zhejiang Province were used. A total of 2 896 participants aged 44-84 years were included in the final analysis. Overweight was defined as 23.0 kg/m 2≤BMI<25.0 kg/m 2, and obesity was defined as BMI ≥25.0 kg/m 2 based on the criteria recommended by WHO/West Pacific Region. Multiple linear regression model was used to evaluate the association between BMI and calcaneus bone mineral density. Restricted cubic splines were used to investigate the dose-response relationship between BMI and calcaneus bone mineral density. Results:The calcaneus bone mineral density in the study subjects were as follow ( x± SE): the broadband ultrasound attenuation was (109.4±12.1) dB/MHz, the speed of ultrasound was (1 545.9±33.8) m/s, and the stiffness index was 85.7±15.8. After adjusting for socio-demographic factors, lifestyle, waist circumference, diabetes and hypertension prevalence, BMI was positively associated with calcaneus stiffness index in non-overweight and non-obese adults, with β of 2.30 (95% CI: 1.11-3.49) for men ( P<0.001) and 1.08 (95% CI: 0.38-1.78) for women ( P=0.003), respectively. In addition, BMI was positively associated with calcaneus stiffness index in overweight and obese women ( β=0.90, 95% CI: 0.38-1.42) ( P<0.001), and null association was found in overweight and obese men ( β=0.06, 95% CI: -0.92-1.04) ( P=0.900). Restricted cubic spline model showed a nonlinear dose-response relationship between BMI and calcaneus stiffness index. Conclusion:Non-linear association was found between BMI with calcaneus bone mineral density in adults.

Objective:To investigate the mode and timing of delivery in pregnant women with complex fetal congenital heart disease (CHD) detected by prenatal ultrasound.Methods:The clinical data of 123 fetuses with complex CHD detected by prenatal ultrasound in Peking University People′s Hospital from January 2016 to December 2023 were retrospectively analyzed. Pregnant women with indications for prenatal diagnosis underwent G-banding karyotype analysis, single nucleotide polymorphism array (SNP arrry) or whole exome sequencing after informed consent. Integrated managements were provided for pregnant women with complex CHD during pregnancy and perinatal period, and to determine the mode and timing of delivery. Infants with complex CHD received timely treatment or referral after birth.Results:The gestational age at ultrasound diagnosis of the 123 fetuses with complex CHD was (23.7±3.4) weeks. There were 11 cases (8.9%) of total anomalous pulmonary venous connection (TAPVC), 14 cases (11.4%) of anomalous pulmonary valve (PVA), 7 cases (5.7%) of right ventricle double outlet (RVDO), 13 cases (10.6%) of anomalous aortic arch, 69 cases (56.1%) of transposition of the great arteries (TGA), 9 cases (7.3%) of other types. All cases were treated with fetal preservation after prenatal consultation. Among the 72 cases undergoing prenatal diagnosis, 9 cases (12.5%) had chromosomal variations. Fifty-five cases (44.7%, 55/123) underwent trial of labor, of which 46 cases (37.4%, 46/123) had successful vaginal delivery, including 6 cases of forceps delivery, and other 9 cases of failed trial of labor transferred to cesarean section. A total of 77 cases of pregnant women underwent cesarean section. Except for the 21 cases of pregnant women who asked for cesarean section, the cesarean section rate of pregnant women with complex CHD was 45.5% (56/123), which was not significantly different from the average cesarean section rate of the same period in our hospital (40.2%; χ2=7.34, P=0.270). The gestational age at delivery of the 123 fetuses with complex CHD was (37.9±1.4) weeks, the birth weight of the neonates was (3 099±480) g, and the umbilical artery blood pH value was 7.31±0.05. The oxygen saturation of 86 cases before and after alprostadil infusion were (72.8±6.0)% and (80.5±5.0)%, respectively, and the difference was statistically significant ( t=4.38, P<0.001). One hundred and fourteen children underwent surgical treatment, 112 of them (98.2%) had good postoperative reexamination. Only 2 cases (1.8%) died after surgery, and 14.0% (16/114) had the possibility of secondary surgery. Conclusions:Fetal complex CHD is not an indication for cesarean section, and the delivery mode could be selected according to the obstetric situation. If the mother and child are in stable condition, the delivery is planned after 39 weeks of gestation. For children with low oxygen saturation after birth, alprostadil could be pumped to maintain the open ductus arteriosus, and timely referral to the pediatric cardiac surgery for subsequent surgical treatment, which could achieve a good prognosis.

Objective:To explore the dosimetry optimization strategy based on filter thickness and shape selection for the bulb superficial X-ray radiotherapy unit.Methods:Monte Carlo code TOPAS was used to model tubular equipment, and the dose distribution from six X-ray energies (50-150 kV) and five conventional aluminum filters (0.5-3.0 mm) with different thickness were simulated in the water model. The percentage depth dose (PDD) curve along the central axis, the center-axis profile dose at different depths, and the lateral dose distribution were analyzed. The dose distribution of three different designs of aluminum filters (conventional cylindrical, conical and oblique cylindrical filters) was compared to evaluate the effect of dosimetric optimization of different filter shapes.Results:Under the same energy, increasing the thickness of the filter can optimize the superficial skin dose, and the optimization effect of depth dose uniformity can be increased by 26% at a depth of 5.5 mm at 70 kV energy. The raised, flat and inclined dose distribution modes can be achieved by using conventional cylindrical, conical and inclined aluminum filters.Conclusions:By selecting the appropriate X-ray energy and filter thickness, an ideal dose distribution matching the tumor depth can be achieved. The application of personalized filters is also of great significance for diverse target areas.

Objective:To investigate the application of the conjugate gradient (CG) algorithm to treatment plan optimization for intensity-modulated brachytherapy (IMBT).Methods:The general Monte Carlo software TOPAS was utilized to simulate the 192Ir source of IMBT, and the unit dose contribution matrix was calculated. An objective function was established using the weighted least squares method and was solved using the CG algorithm to achieve optimized IMBT treatment plans. The optimization was validated using five clinical cervical cancer cases under modulation width 60°. The dose distributions of IMBT treatment plans under 45°, 60°, 90°, 120°, and 180° modulation widths were compared using the Wilcoxon test to determine the optimal IMBT treatment plan for cervical cancer treatment. Results:The CG algorithm successfully optimized IMBT treatment plans under modulation width 60° for five cases within 22.2 s on average. On the premise of sufficient target dose coverage, the average D2 cm 3 values of the bladder and rectum in IMBT treatment plans were 3.66 and 1.97 Gy, respectively, representing reductions of 0.54 and 0.69 Gy compared to traditional brachytherapy plans. For the five modulation widths, the D90% values of all IMBT treatment plans reached 6 Gy, without statistically significant differences ( P > 0.05). The average D2 cm 3 values of the bladder in IMBT treatment plans were significantly lower than those in the traditional brachytherapy plans( P<0.05), with modulation width 60° associated with the greatest reduction of 0.61 Gy. In contrast, the average D2 cm 3 values of the rectum under 45°, 60°, and 90° modulation widths decreased by 0.63, 0.54, and 0.45 Gy, respectively, compared to traditional plans, with statistically significant differences( P<0.05). Conclusions:The CG method enables rapid achievement of optimized IMBT treatment plans that meet clinical requirements, and modulation width 60° contributes to valid dosimetric optimization. This study can serve as a guide for the clinical implementation of IMBT.

Objective:To rapidly and accurately detect volumetric modulated arc therapy (VMAT) plans with potentially inaccurate radiation doses.Methods:The measurement-based dosimetric verification result of 196 VMAT plans obtained using ArcCHECK phantoms were retrospectively collected. Independent dosimetric calculation and verification were conducted for these plans using the ArcherQA system based on a fast Monte Carlo algorithm. The gamma passing rates of dosimetric verification using ArcCHECK phantom and the ArcherQA system were compared, followed by their correlation analysis and linear regression fitting. The ArcherQA system′s gamma passing rate threshold used to detect positive dosimetric verification result obtained using ArcCHECK phantoms, as well as the specificity of the detection, were calculated. Based on this gamma passing rate threshold, another 50 VMAT plans were selected as a test set to assess the ArcherQA system′s ability to detect positive measurement-based dosimetric verification result.Results:The average gamma passing rates for the dosimetric verification of the VMAT plans using the ArcherQA system and ArcCHECK phantoms were 97.28% and 96.57% (3%/3 mm, TH=10%), respectively. Both rates had a correlation coefficient of 0.71 ( P < 0.01) and a linear fitting coefficient of 0.54 ( R2=0.51). When the gamma passing rate for dosimetric verification using ArcCHECK phantoms was set at 90% (3%/2 mm, TH=10%), the gamma passing rate threshold for dosimetric verification using the ArcherQA system should be adjusted to 94.8% to detect all VMAT plans with positive dosimetric verification result obtained using ArcCHECK phantoms, with a specificity of 67.8%. Using this threshold, the ArcherQA system detected all VMAT plans in the test set for which ArcCHECK phantom-based measurement yielded positive dosimetric verification result. Conclusions:By determining an appropriate gamma passing rate threshold, the ArcherQA system can rapidly and accurately detect VMAT plans with potentially inaccurate doses, thus ensuring treatment accuracy and improving work efficiency.

Toxin-antitoxin(TA)systems serve as central hubs of bacterial adaptive regulation and play critical roles in the pathogenesis of Mycobacterium tuberculosis(M.tb)and Bordetella pertussis(B.per-tussis).This review summarizes the functional evolution and therapeutic potential of TA systems in M.tb and B.pertussis.It systematically outlines the molecular mechanisms and pathogenic functions of TA sys-tems in these two pathogens.M.tb relies on type Ⅱ TA systems(e.g.,VapBC,MazEF)to drive persis-ter formation and antibiotic tolerance through toxin-mediated ribonuclease activity that cleaves host nucle-ic acids or DarT/DarG-mediated DNA modification.In contrast,B.pertussis utilizes a unique tempera-ture-sensing PhtA/PhtB system to release adenylate cyclase toxin,which targets the host cAMP signaling pathway to achieve immune evasion.Both pathogens employ TA toxins to suppress host defenses-such as VapC cleaving tRNA and RelE degrading NF-κB components.Their high-frequency mutation sites(e.g.,the VapC47-Ser46Leu mutation frequency＞50 000 in M.tuberculosis)reveal strong positive selec-tion pressure,closely associated with persister phenotypes and virulence evolution.This review further discusses therapeutic strategies,including small-molecule inhibitors targeting toxin-antitoxin interactions,TA-deletion attenuated vaccines,and antitoxin-based immunization approaches.Finally,it highlights the need for future research to elucidate TA-host interaction networks and develop nanocarrier delivery tech-nologies to advance breakthroughs in precision therapy for tuberculosis and pertussis.

Pancreatic cancer is highly aggressive and often diagnosed at an advanced stage,leaving most patients ineligible for radical resection.This study retrospectively analyzed four patients with locally advanced or advanced pancreatic cancer to evaluate the clinical efficacy and safety of high-intensity focused ultrasound(HIFU)ablation combined with chemotherapy as a neoadjuvant and conversion therapy.All cases were reviewed and individualized treatment plans were formulated through a multidisciplinary team evaluation.All patients received HIFU plus gemcitabine and nab-paclitaxel chemotherapy,with assessments of tumor volume,vascular involvement,surgical conversion,symptom relief,and adverse events.Three patients achieved marked tumor shrinkage and reduction of vascular invasion,enabling successful R0 resection without recurrence during follow-up.The remaining patient achieved disease stability,significant pain relief,and maintained good quality of life under repeated HIFU therapy.All treatments were well tolerated,and no severe adverse reactions occurred.The combination of HIFU and chemotherapy demonstrated synergistic local and systemic effects,effectively achieving tumor downstaging,improving resectability,and alleviating symptoms.As a safe,noninvasive,and repeatable therapeutic approach,this strategy offers a promising option for patients with advanced pancreatic cancer.Further large-scale prospective studies are warranted to validate its long-term efficacy and elucidate underlying mechanisms.