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 This study conducted molecular biological identification of the viruses carried by Culex pipiens pallens specimens collected in Shunyi District, Beijing in 2023, and observed the changes in the infection rate of the viruses carried by Cx. pipiens pallens at different collection times. Methods Cx. pipiens pallens were collected using carbon dioxide mosquito traps. The mosquito samples were ground in batches and analyzed by molecular biology technologies. The virus infection rate at different collection times was analyzed statistically. Results 17 strains of Culex pipiens pallens densovirus(CppDNV)were identified from Cx. pipiens pallens samples collected in Shunyi District, Beijing, in 2023. The nucleotide sequence analysis of the virus genome coding region showed that CppDNV was a single-stranded DNA virus with a total length of 3 335 nt, encoding 2 non-structural proteins(NS1, NS2)and 1 capsid protein(VP). The nucleotide(amino acid)sequence lengths of the three proteins were 2 376 nt(791 aa),1 092 nt(363 aa)and 1 071 nt(356 aa), respectively. Phylogenetic analysis showed that CppDNV was located in genus Brevihamaparvovirus. Statistical analysis showed no significant difference in infection rates across collection times(χ2=4.429, P=0.194). Conclusions CppDNV was identified in Cx. pipiens pallens in Beijing, and it was stably maintained in this natural population.

Objective To investigate the species composition of mosquitoes and breeding conditions of larvae in the rice planting areas of Beijing, and to provide a scientific basis for mosquito control in rice fields. Methods Adult mosquitoes were collected using CO2-baited light traps, and mosquito larvae(including pupae)were sampled via the dipping method. Results A total of 4 genera and 6 species of adult mosquitoes were captured in the study area. The dominant species were Culex pipiens pallens, Cx. tritaeniorhynchus, and Anopheles sinensis. The average adult mosquito density was 5.11 specimens per trap-hour, with slightly lower density in July compared to August. For larvae and pupae,3 genera and 4 species were identified, dominated by Cx. tritaeniorhynchus, An. sinensis, and Aedes vexans. Conclusions The mosquito species composition in Beijing′s rice planting areas is diverse. Mosquito control strategies should prioritize the management of adult mosquitoes, while density control of mosquito larvae in paddy fields can be achieved through intermittent irrigation techniques.

Objective To investigate the effect and mechanism of melatonin in alleviating hypoxia-induced apoptosis in ovarian gra-nulosa cells.Methods Rat ovarian granulosa cells were isolated and divided into normoxic,hypoxic,and melatonin groups.Hypoxia-induced injury models were established in the hypoxic and melatonin groups,and granulosa cells in the melatonin group were treated with melatonin.A total of 24 rats were randomized into the control,model,and intervention groups(n=8 per group).Rat models of declining ovarian function induced by long-term hypoxia were established in the model and intervention groups.The rats in the intervention group were intraperitoneally injected with melatonin.Cell proliferation was measured using a CCK-8 assay,and lactate secretion and HIF-1αprotein with a specific kit,respectively.The levels of estradiol and progesterone in the cell supernatant and rat serum were detected using ELISA.Granulosa cell apoptosis was detected by flow cytometry,ovarian morphology by HE staining,and Bax and caspase-3 expression by Western blotting.Results Compared with the normoxic group,the hypoxic group exhibited decreased granulosa cell proliferation,increased apoptosis,elevated lactate and HIF-1α levels,and reduced estradiol and progesterone levels(P＜0.05).Compared with hypoxic group,these changes were significantly reversed in the molatonin group(P＜0.05).Compared with the control group,the model group showed increased lactate,HIF-1α,Bax,and caspase-3 levels,decreased estradiol and progesterone levels,and reduced follicles.Compared with the model group,all the indicators were ameliorated in the intervention group(P＜0.05).Conclusion Melatonin alleviated hypoxia-induced granulosa cell apoptosis and promoted the recovery of ovarian function.

Objective To observe the origin and course of the obturator artery(OA),so as to provide anatomical reference for reducing hemorrhage during pelvic surgery and pubic fracture fixation.Methods A total of 65 human hemi-pelvises specimens with intact structure were dissected to observe the origin,course and other variations of OA.Measure the length of the inner section of OA basin and the outer diameter at the origin,etc.Results OA originated from the internal iliac artery in 57 cases(87.7%),including 3 cases(4.6%)of the superior gluteal artery,5 cases(7.7%)of the inferior gluteal artery,3 cases(4.6%)of the external iliac artery and 5 cases(7.7%)of the inferior epigastric artery.OA participated in the formation of the arterial trunk in 3 cases(4.6%).The length of the pelvic segment of the OA in male and female was(50.87±15.41)mm and(51.71±14.19)mm,respectively,with no statistically significant difference between them(P>0.05).The outer diameters at the origin of the OA in male and female were(2.79±1.05)mm and(2.35±0.86)mm,and there was no statistically significant difference between them(P>0.05).Conclusion OA mainly originated from the anterior trunk of the internal iliac artery,with a few OA originated from the branches of the posterior trunk or the inferior epigastric artery,or participated in the formation of the arterial trunk.In pelvic surgery involving OA area,attention should be paid to the length of its pelvic segment and the outer diameter at the origin of OA,so as to better locate and protect blood vessels during surgery.

Objective To develop an enteral nutrition delivery device for nasal feeding patients to relieve gastrointestinal discomfort during enteral nutrition therapy and solve the problems in heating,quality preservation and constant temperature maintenance of the solution.Methods The enteral nutrition delivery device was mainly composed of a nasal feeding container,a fixing frame,a limiting trough,a heating wire,a temperature control unit and a speed control unit.The heating wire and temperature and speed control units were combined to facilitate the nasogastric solution in the container to be delivered to the patient's stomach and intestines at a constant temperature and a uniform speed.The device developed had its shell made of 304 waterproof stainless steel and the nasal feeding container made of 05-polypropylene.Results The device developed realized constant-temperature and uniform-speed delivery and auto cleaning,and could reduced effectively gastrointestinal adverse reactions during nasal feeding.Conclusion The device developed gains advantages in easy operation and autonomous feeding,and thus is worth promoting for nasal feeding patients clinically.[Chinese Medical Equipment Journal,2025,46(2):108-111]

Objective:To analyze the clinical and ultrasonic features of breast invasive ductal carcinoma in young women patients,and improve the accuracy of ultrasonic diagnosis of breast invasive ductal carcinoma in young patients.Methods:A retrospective study was conducted on patients with invasive ductal carcinoma who underwent surgery in the Second Hospital of Shandong University from December 2015 to June 2023,with complete clinical data,preopera-tive ultrasonography and postoperative pathology.All patients were divided into two groups:young group(≤35 year-old)and control group(>35 year-old).Univariate t-test and multivariate Logistic regression analyses were used to assess the factors.Results:There was a statistical difference between the young group and the control group in the accuracy of ultrasound diagnosis(young group 81%vs control group 94%,χ2=13.082,P=0.001).Compared with the control group,the young group had a shorter disease history,a higher proportion of multiple masses,posterior echo changes and hypo-vascular lesions(P<0.05).However,there was no statistical difference in family history of breast cancer,other cancer family history,clinical symptoms,size,lesion classification,palpation,location,aspect ratio,focus echo,shape,edge per-formance,bright ring sign,calcification characteristics,ER,PR,HER-2 and Ki67(P>0.05).Conclusion:The incidence rate of young breast IDC is low,while the misdiagnosis rate of ultrasound is relatively high.More attention should be paid when the patient has a short history,multiple masses,changes in the posterior echo and less lesion blood supply.

Objective To observe the origin and course of the obturator artery(OA),so as to provide anatomical reference for reducing hemorrhage during pelvic surgery and pubic fracture fixation.Methods A total of 65 human hemi-pelvises specimens with intact structure were dissected to observe the origin,course and other variations of OA.Measure the length of the inner section of OA basin and the outer diameter at the origin,etc.Results OA originated from the internal iliac artery in 57 cases(87.7%),including 3 cases(4.6%)of the superior gluteal artery,5 cases(7.7%)of the inferior gluteal artery,3 cases(4.6%)of the external iliac artery and 5 cases(7.7%)of the inferior epigastric artery.OA participated in the formation of the arterial trunk in 3 cases(4.6%).The length of the pelvic segment of the OA in male and female was(50.87±15.41)mm and(51.71±14.19)mm,respectively,with no statistically significant difference between them(P>0.05).The outer diameters at the origin of the OA in male and female were(2.79±1.05)mm and(2.35±0.86)mm,and there was no statistically significant difference between them(P>0.05).Conclusion OA mainly originated from the anterior trunk of the internal iliac artery,with a few OA originated from the branches of the posterior trunk or the inferior epigastric artery,or participated in the formation of the arterial trunk.In pelvic surgery involving OA area,attention should be paid to the length of its pelvic segment and the outer diameter at the origin of OA,so as to better locate and protect blood vessels during surgery.

Streptococcus equinus is a zoonotic disease that can cause illness in various animals under specific environmental condi-tions.No reports have described isolation of this bacterium from the liver in affected sheep.This study successfully isolated and identi-fied a strain of Streptococcus equinus through bacterial isolation and culture,Gram staining,drug sensitivity testing,mouse sensitivity testing,bacterial biochemical testing,and whole genome sequencing.The strain was found to have pathogenicity toward Kunming white mice,and to be sensitive to four antibiotics(penicillin,ampicillin,ceftiofur sodium,and ceftriaxone sodium)but resistant to four antibiotics(streptomycin,amoxicillin,tetracycline,and gentamicin).On the basis of drug sensitivity testing,targeted treatment of the affected sheep flock with ceftiofur sodium effectively controlled the disease within 2 days,and no new cases occurred.This study provides a reference for biological characterization of ovine Streptococcus equinus;public health;and the investigation of disease pre-vention,control,and epidemiology.