A novel sesquiterpene lactone fraction from Eupatorium chinense L. suppresses hepatocellular carcinoma growth by triggering ferritinophagy and mitochondrial damage.

BACKGROUND: Hepatocellular carcinoma (HCC) is an aggressive tumor with limited treatment options, and it is the third leading cause of cancer-related deaths. Hence, novel therapeutic strategies are required to treat HCC. Eupatorium chinense L. is a traditional Chinese medicine (TCM) that can effectively neutralize heat and smoothen the flow of "Qi" through the liver. However, the anti-HCC effects of Eupatorium chinense L. remain unknown. PURPOSE: The present study investigated the anti-HCC effects and the underlying mechanisms of the electrophilic sesquiterpenes isolated from E. chinense L. (EChLESs) in the regulation of ferroptosis and apoptosis in HCC cells. STUDY DESIGN/METHODS: Cell viability was assessed by the MTT assay. Cell apoptosis was confirmed by flow cytometry and western blotting assay. Ferroptosis was assessed by flow cytometry, transmission electron microscopy, and western blotting assay. Ferritinophagy was detected by acridine orange staining and western blotting assay. Small interfering RNA of nuclear receptor coactivator 4 (NCOA4) was used to confirm the role of ferritinophagy in the therapeutic effect of EChLESs on HCC cells. A mouse xenograft model was constructed to determine the inhibitory effect of EChLESs on HCC in vivo. RESULTS: EChLESs induced apoptosis by disrupting mitochondrial membrane potential depolarization and mitochondrial reactive oxygen species. EChLESs induced ferroptosis as noted by a significant increase in mitochondrial disruption, lipid peroxidation, and intracellular iron level and decreased glutathione level. The apoptosis inhibitor Z-VAD-FMK and lipid reactive oxygen species scavenger ferrostatin 1 attenuated EChLESs-induced cell death. NCOA4-mediated ferritinophagy through autophagic flux was the crucial pathway for ferroptosis induced by EChLESs. NCOA4 knockdown alleviated EChLESs-induced cell death. EChLESs controlled the expression of NCOA4 at the transcriptional and post-transcriptional levels. In the in vivo experiment, EChLESs suppressed HCC growth in the xenograft tumor mouse model. CONCLUSION: EChLESs enhances cell apoptosis through mitochondrial dysfunction and ferroptosis through NCOA4-mediated ferritinophagy. Thus, Eupatorium chinense L. could be a potential TCM for treating HCC.

Serum free triiodothyronine is inversely associated with diabetic peripheral neuropathy but not with carotid atherosclerotic lesions in euthyroid patients with type 2 diabetes.

BACKGROUND: The associations between serum free triiodothyronine (FT3) and diabetic peripheral neuropatprohy (DPN)/carotid atherosclerotic lesions in euthyroid patients with type 2 diabetes are still unclear. The purpose of our study was to explore the relations of FT3 to DPN and carotid atherosclerotic lesions in Chinese type 2 diabetes inpatients with euthyroid function. METHODS: 2477 euthyroid inpatients with type 2 diabetes were recruited and they were stratified into quartiles by FT3 levels in this cross-sectional study. Peripheral neuropathy was assessed by neurological symptoms and signs as well as nerve conduction velocity tests. Carotid atherosclerotic lesions, including carotid intima-media thickness, plaque and stenosis, were evaluated by Doppler ultrasound. RESULTS: The prevalence of DPN in type 2 diabetic patients exhibited the significant decrease across the FT3 quartiles (23.5%, 20.9%, 18.8%, and 11.2%, respectively, p < 0.001). Multiple logistical regression analysis also revealed that FT3 quartiles were significantly and inversely associated with DPN. Compared with the subjects in the highest FT3 quartile, the adjusted odds ratios (95% confidence interval) of DPN from the first to third FT3 quartile were successively 2.338 (1.407-3.884), 1.903 (1.134-3.194) and 1.598 (0.960-1.125). The patients with DPN had significantly higher prevalence of carotid atherosclerotic lesions compared with non-DPN patients. However, no statistical association was observed between FT3 quartiles and carotid atherosclerotic lesions after adjusting for confounder factors. CONCLUSIONS: Lower FT3 within the normal range was independently associated with DPN, but not with carotid atherosclerotic lesions in Chinese euthyroid inpatients with type 2 diabetes.

Endothelial peroxynitrite causes disturbance of neuronal oscillations by targeting caspase-1 in the arcuate nucleus.

Severe anorexia limits the clinical application of cisplatin, and even leads to the discontinuation of treatment. However, the mechanisms underlying cisplatin-induced anorexia are unknown. Herein, we demonstrated that cisplatin could affect neuronal gamma oscillations and induce abnormal neuronal theta-gamma phase-amplitude coupling in the arcuate nucleus (Arc) of the hypothalamus, and these findings were associated with significantly decreased food intake and weight loss in mice. Chemogenetic activation of AgRP neurons in the Arc reversed the cisplatin-induced food intake reduction in mice. We further demonstrated that endothelial peroxynitrite (ONOO-) formation in the Arc induced nitrosative stress following cisplatin treatment via a previously uncharacterized pathway involving neuronal caspase-1 activation. Strikingly, treatment with the ONOO- scavenger uric acid (UA) reversed the reduced action potential (AP) frequency of AgRP neurons and increased the AP frequency of POMC neurons induced by SIN1, a donor of ONOO-, in the Arc, as determined by whole-cell patch-clamp electrophysiological recording. Consistent with these findings, UA treatment effectively alleviated cisplatin-induced dysfunction of neuronal oscillations and neuronal theta-gamma phase-amplitude coupling in the Arc of mice. Taken together, these results suggest, for the first time, that targeting the overproduction of endothelial ONOO- can regulate cisplatin-induced neurotoxicity through neuronal caspase-1, and thereby serve as a potential therapeutic approach to alleviate chemotherapy-induced anorexia and weight loss.

Anatomic study of the femur-vastus intermedius muscle-anterolateral thigh osteomyocutaneous free flap.

INTRODUCTION: Resection of head and neck malignancy usually causes facial defects and esthetic deformities. Among the wide range of free flaps available for reconstruction, a novel chimeric free flap-the femur-vastus intermedius muscle-anterolateral thigh osteomyocutaneous free flap (FVATLO flap)-has been demonstrated for clinical use. In this study, we illustrate the anatomy and harvest of the FVATLO flap. METHODS: Eighteen fresh cadavers without damage to either thigh were recruited for dissection. Blood supply to the vastus intermedius muscle and femur were traced and recorded. The diameter, circumference of the middle part of the femur, and thickness of the femoral cortex were measured. RESULTS: The major blood supply to the vastus intermedius muscle showed two patterns of origin. The first arising from the descending branch of the lateral circumflex femoral artery (LCFA-db) accounts for 78% of the cases (28/36), and the second arising from the transverse branch of the lateral circumflex femoral artery (LCFA-tb) accounts for 22% (8/36). Blood supply to the femur consists of two major sources: one from branches penetrating through the nutrient foramen on the posteromedial surface of the femur to the medullary cavity, and the other from the periosteum branches spreading over on the femoral surface. No visible branch from the vastus intermedius muscle to the underlying periosteum was found. The mean diameter, femoral circumference, and mean cortical thickness were 26.30 mm, 85.58 mm, and 6.85 mm, respectively. CONCLUSION: Considering that there is only one injured donor site, the FVALTO flap is an alternative chimeric flap for cases with a large amount of soft tissue loss together with small bony defects.

[Regulation of ß-mercuryl alcohol metabolic flow in Saccharomyces cerevisiae cells].

In this study, citrate synthase gene(CIT2), and malate synthase gene(MLS1) were successfully knocked out in ß-amyrin-producing yeast cells by using CRISPR/CAS9. The promoter of phosphoglucose isomerase gene(PGI1) was replaced by that of cytochrome c oxidase subunit Ⅶa(Cox9)to weaken its expression, aiming to channel more carbon flux into the NADPH-producing pathway. The fermentation results showed that CIT2 deletion had no effect on the ß-amyrin production. Compared with the control strain, the production of ß-amyrin was increased by 1.85 times after deleting MLS1, reaching into 3.3 mg·L~(-1). By replacing the promoter of PGI1, the ß-amyrin yield was 3.75 times higher than that of the control strain, reaching up to 6.7 mg·L~(-1). This study successfully knocked out the CITT2 and MLS1 genes and weakened the PGI1 gene by using CRISPR/CAS9, which directly influenced the production of ß-amyrin and provided some reference for the the metabolic engineering of triterpernoid producing strain.

The prognostic value of volumetric reduction of the target lesions after induction chemotherapy in locoregionally advanced nasopharyngeal carcinoma.

BACKGROUND: We explored whether the volumetric reduction ratio of target lesion after induction chemotherapy (IC) had any prognostic value in nasopharyngeal carcinoma (NPC). METHODS: From 2013 to 2016, 72 NPC patients treated with PCF (paclitaxel, cisplatin, 5-fluorouracil) IC followed by cisplatin-based concurrent chemoradiotherapy were analyzed. The volumes of target lesions before and after IC and survival conditions were assessed. RESULTS: For all cases, volumetric reduction ratios of the total tumor load ≥ optimal cutoff values were significantly associated with increased 2-year progression-free survival, locoregional failure-free survival, and distant metastasis-free survival (DMFS) rates, and for cervical lymph nodes, the volumetric reduction ratio ≥ optimal cutoff value was significant for DMFS (all P < .05). Accordingly, the optimal cutoff values were 24.56% (AUC = 60.5%), 23.91% (AUC = 57.7%), 29.77% (AUC = 75.8%), and 34.17% (AUC = 62.5%), respectively. CONCLUSION: Volumetric reductions of target lesions after IC are independent survival predictors for NPC, especially for those with N2/N3 disease.

Non-destructive characterization of egg odor and fertilization status by SPME/GC-MS coupled with electronic nose.

BACKGROUND: Early and non-destructive identification of fertile (F) eggs is a difficult task in the process of breeding laying hens. The odors emitted from unfertilized (UF), infertile (IF), and fertile (F) eggs were characterized by solid-phase microextraction / gas chromatograph-mass spectrometry (SPME/GC-MS) and electronic nose (E-nose) to determine their differences by principal component, partial least squares, and canonical discriminant analyses. RESULTS: A total of 14 volatiles were identified in unhatched shell white Leghorn eggs, such as nonanal, decanal, 6-methyl-5-hepten-2-one, and 6,10-dimethyl-5,9-undecadien-2-one. Cedrene and decanal contributed greatly to the classification of UF and fertilized (Fd)/IF eggs; cedrene, decanal, 1-octanol and hexanal contributed greatly to the distinction between UF and IF eggs; heptanal might be the potential marker to determine F/IF eggs. P40/1, P10/2, P10/1, TA/2, T40/2 and T30/1, P30/1, P40/2, PA/2, T40/2 mostly contributed to the distinction between UF and Fd eggs and between F and IF eggs, respectively. Canonical discriminant analysis presented superior differentiating efficiency for almost all groups, and the odor differences between UF and Fd eggs were significantly larger than the differences between F and IF eggs. CONCLUSION: Solid-phase microextraction / gas chromatograph-mass spectrometer combined with E-nose may have the potential to non-destructively distinguish UF, F, and IF eggs, which will provide a new perspective to understand the differences among them. © 2018 Society of Chemical Industry.

UVB Radiation Delays Tribolium castaneum Metamorphosis by Influencing Ecdysteroid Metabolism.

Ultraviolet B (UVB) radiation is an important environmental factor. It is generally known that UVB exhibits high genotoxicity due to causing DNA damage, potentially leading to skin carcinogenesis and aging in mammals. However, little is known about the effects of UVB on the development and metamorphosis of insects, which are the most abundant terrestrial animals. In the present study, we performed dose-response analyses of the effects UVB irradiation on Tribolium castaneum metamorphosis, assessed the function of the T. castaneum prothoracicotropic hormone gene (Trcptth), and analyzed ecdysteroid pathway gene expression profile and ecdysterone titers post-UVB irradiation. The results showed that UVB not only caused death of T. castaneum larvae, but also delayed larval-pupal metamorphosis and reduced the size and emergence rate of pupae. In addition, we verified the function of Trcptth, which is responsible for regulating metamorphosis. It was also found that the expression profiles of Trcptth as well as ecdysteroidogenesis and response genes were influenced by UVB radiation. Therefore, a disturbance pulse of ecdysteroid may be involved in delaying development under exposure to irradiation. To our knowledge, this is the first report indicating that UVB can influence the metamorphosis of insects. This study will contribute to a better understanding of the impact of UVB on signaling mechanisms in insect metamorphosis.

[Inhibitory effect of Genipin on uncoupling protein-2 and energy metabolism of androgen-independent prostate cancer cells].

OBJECTIVE: To explore whether the inhibitory effect of Genipin on uncoupling protein-2 (UCP-2) in mitochondria is involved in energy metabolism of androgen-independent PC3 prostate cancer cells. METHODS: PC3 prostate cancer cells were cultured and treated with Genipin at the concentrations of 40, 80, and 160 µmol/L for 48 hours. Then the proliferation of the cells was detected by MTT assay, the expression of UCP-2 mRNA determined by RT-PCR, and the content of intracellular pyruvic acid (PA) and the activity of succinate dehydrogenase (SDH) in the mitochondria measured by visible spectrophotometry. RESULTS: With the increased concentration of Genipin, the proliferative activity of the PC-3 cells, the expression level of UCP-2 mRNA, the content of intracellular PA and the activity of SDH in the cells were all decreased, namely, with the enhanced inhibitory effect of Genipin on UCP-2, a trend of reduction was observed in the proliferation of the cells, intracellular PA content, and SDH activity in the mitochondria. CONCLUSION: Genipin is involved in the energy metabolism of androgen-independent PC3 prostate cancer cells by reducing the content of intracellular PA and the activity of SDH in the mitochondria, which may be associated with its inhibitory effect on UCP-2.

[STC-1 is involved in anti-hypoxia proliferative balance of renal cancer cells by down-regulation of intracellular Ca2+ and HIF-1α levels].

OBJECTIVE: To investigate effects of stanniocalcin-1 (STC-1) on proliferation balance under hypoxic condition in renal cancer cells and its mechanism. METHODS: Hypoxic model was induced on renal cancer GRC-1 cells (Group H), the cells were treated with STC-1 protein at concentrations of 0.1 nmol/L (H1), 0.5 nmol/L (H2), 1.0 nmol/L (H3), or normal saline (H0) for 48 h， respectively. Cells proliferation was measured by MTT assay; mRNA and protein expressions of hypoxia inducible factor 1α (HIF-1α) and STC-1 in GRC-1 cells were detected by RT-PCR and ELISA, respectively; the intracellular levels of Ca2+ and adenosine triphosphate (ATP) were determined by fluorescence spectrophotometry and spectrophotometry, respectively. RESULTS: The expression of HIF-1α, STC-1 and Ca2+ levels were increased in GRC-1 cells under hypoxia condition; STC-1 reversed these changes in a dose-effect manner. Hypoxia significantly inhibited cell proliferation and the generation of ATP in GRC-1 cells and exogenous STC-1 reversed the effects of hypoxia; ATP generation increased gradually with increasing STC-1 concentration, but the cell proliferation was reduced. CONCLUSION: Exogenous STC-1 can promote the proliferation of renal cancer cells in hypoxia condition by reducing HIF-1α expression and Ca2+ content and increased ATP production, but the progressive inhibition of HIF-1 α hindered the renal carcinoma cell proliferation further, which indicates that STC-1 may be involved in anti-hypoxia proliferative balance of renal cancer cells.

Differential temporal expression profiles of heat shock protein genes in Drosophila melanogaster (Diptera: Drosophilidae) under ultraviolet A radiation stress.

Solar UV radiation is indispensable for certain behaviors of many organisms. Nevertheless, UV-A might be expected to stress insects that possess intensive positive taxis toward UV-A light. To avoid stress hazards, organisms generally exhibit the upregulation of heat shock proteins (Hsps) expression. To gain a better understanding of the roles of the different Hsps in response to UV-A stress in the diurnal phototactic fly Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae), we tested the temporal expression patterns of 11 DmHsps following UV-A radiation. The results indicated that each DmHsp had a differential temporal expression profile under UV-A radiation stress. Potential transcription factor-binding motifs in the promoter regions of strongly inducible DmHsps were identified; results showed these transcription factor-binding motifs were highly homologous to binding sites that have been identified for transcription factors associated with UV radiation stimuli. So DmHsps might act in a coordinated and cooperative manner at the transcriptional level to counteract UV-A radiation-based stress.

[Effects of stanniocalcin-1 and hypoxia-inducible factor-1α on mitochondrial membrane potential stability in renal carcinoma cells].

OBJECTIVE: To explore the effects of stanniocalcin-1 (STC-1) and hypoxia-inducible factor-1α (HIF-1α) on the calcium and thus on the mitochondrial membrane potential (Δψm) in renal carcinoma cells. METHODS: We successfully established the renal carcinoma cell models with high HIF-1α gene expression. After various concentrations of STC-1 solutions were added to the culture medium, the proliferation of cells, expressions of HIF-1α and STC-1, levels of Ca(2+), Δψm, and mPTP were detected by MTT, RT-PCR, ELISA, fluorescence spectrophotometry, and ultraviolet spectrophotometry, respectively. RESULTS: The proliferation of renal carcinoma cells and Δψm were improved after HIF-1α gene transfection, STC-1 protein intervention, and STC-1 protein intervention after gene transfection. While the intracellular Ca(2+) level and mPTP were decreased significantly (P<0.05), all the changes were intensified with the gradual increase of STC-1. However, the increasing trend of cell proliferation gradually declined. CONCLUSION: HIF-1α may participate in malignant proliferation of renal carcinoma cells by promoting STC-1 proliferation or down-regulating Ca(2+); however, such an effect may be gradually attenuated due to the inhibitory effect of STC-1 on HIF-1α.

Identification and transcriptional profiling of differentially expressed genes associated with response to UVA radiation in Drosophila melanogaster (Diptera: Drosophilidae).

Ultraviolet A (UVA) radiation, the major component of solar ultraviolet (UV) radiation reaching the earth's surface, leads to negative effects in insects, such as oxidative stress, photoreceptor damage, and cell death. To better understand the molecular mechanisms of insect response to UVA radiation, suppression subtractive hybridization (SSH) and real-time quantitative polymerase chain reaction approaches were combined to reveal differential transcript expression in Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae). In this study, two subtractive cDNA libraries were constructed and sequenced, obtaining 131 high-quality unique expressed sequence tags (ESTs) that were up- or downregulated in D. melanogaster exposed to UVA radiation for 0.5 h. Of the 131 ESTs, 102 unique ESTs were differentially expressed and classified into 10 functional categories. The results showed that UVA radiation induces expression of genes related to stress and defense response and metabolism. Potential transcription factor binding motifs upstream of these genes are associated with multiple signaling pathways that may help the insect cope with the stress of UVA radiation. To our knowledge, this is the first analysis of insect response to UVA radiation at the transcriptional level. Our results reveal that UVA radiation influences the expression profiles of stress-responsive genes and provide further insights into the mechanisms of adaptive response to UVA radiation stress.

[Analysis of expression pattern of zebrafish leg1 homologus gene mu-leg1 in mouse].

Gene leg1 (liver-enriched gene 1) was first identified as a novel gene whose expression was enriched in the liver of zebrafish. Further studies revealed that Leg1 protein was a novel secretory protein, which played a role in the liver development in zebrafish. Here we reported the analysis of expression pattern of zb-leg1 homologus gene mu-leg1. The cDNA of mu-leg1 was isolated from adult mouse liver by nested PCR. This gene encodes a putative protein, mu-Leg1, which shares 31% similarity with zb-Leg1 of zebrafish. Both Northern blotting and semi-quantitative RT-PCR demonstrated that the expression of mu-leg1 was enriched in the small intestine rather than in the liver in adult mouse. We also produced a recombined mu-Leg1 protein and a mu-Leg1 specific antibody. Western blottingdemonstrated that mu-Leg1 was a secretory protein. In addition, we have established a mu-leg1 conditional knock-out heterozygous mouse. Our work builds a basis for further studies of mu-leg1.

[The detection of hatching eggs prior to incubation by the near infrared spectrum].

The detection of the infertile eggs and fertile eggs by the near infrared diffuse reflectance spectra was proposed. Models based on different band regions range, different principal component numbers and the different spectral pre-processing methods were compared and the optimal calibration model was established. The results show that qualitative forecasting model of hatching eggs is established by Mahalanobis Distance, which is with band regions range being 4 119.20-9 881.46 cm(-1), principal component number being 19 and spectral pre-processing method being SNV + first derivative + Norris differential filter. The precision rate of calibration set is 92.5% and that of validation set is 91.67%. The study provides a new way for nondestructive testing of the fertile eggs and infertile eggs prior to incubation.

The involvement of heat shock protein and cytochrome P450 genes in response to UV-A exposure in the beetle Tribolium castaneum.

Sunlight is an important environmental factor that affects all living organisms on Earth. Ultraviolet A (UV-A) is one of the many frequency bands found in sunlight. Many animals use UV-A to attain visual cues, for example, in foraging and mate selection. However, UV-A can also induce damage, such as oxidative stress, DNA lesions and apoptosis. In the present study, we investigated the effects of UV-A on the survival, fecundity and expression profiles of several stress-responsive genes belonging to the heat shock protein (Hsp) and the cytochrome CYP6BQ families from the adult red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The results showed that short-term UV-A exposure (365 nm, <4h) did not influence the survival or fecundity of the beetles; however, Hsp27, Hsp68, Hsp83, CYP6BQ4 and CYP6BQ8 mRNA levels significantly increased during the first 2h of UV-A exposure. Among them, Hsp68 was the most highly up-regulated, increasing by 8.9-fold. These results indicate that these genes may participate in the defense against harmful UV-A radiation. In addition, we investigated the potential transcription factor binding motifs (TFBMs) in the promoter sequences of genes induced in similar pattern from the Hsp and P450 gene families; the results indicated that, these motifs are highly homologous to environmental stress transcription factor binding sites in mammals. Our experiments revealed that UV-A irradiation could influence the expression profile of stress-responsive genes, such as Hsps and P450s, which have universal TFBMs, and that these genes may be involved in reducing the ecological challenges posed by irradiation.

Expression of cyclooxygenase-2 in human esophageal squamous cell carcinomas.

AIM: To determine whether cyclooxygenase-2 (COX-2) was expressed in human esophageal squamous cell carcinoma. METHODS: Quantitative reverse transcription-polymerase chain reaction (RT-PCR), western blotting, immunohistoc-hemistry and immunofluorescence were used to assess the expression level of COX-2 in esophageal tissue. RESULTS: COX-2 mRNA levels were increased by >80-fold in esophageal squamous cell carcinoma when compared to adjacent noncancerous tissue. COX-2 protein was present in 21 of 30 cases of esophageal squamous cell carcinoma tissues, but was undetectable in noncancerous tissue. Immunohistochemistry was performed to directly show expression of COX-2 in tumor tissue. CONCLUSION: These results suggest that COX-2 may be an important factor for esophageal cancer and inhibition of COX-2 may be helpful for prevention and possibly treatment of this cancer.

[Association between mutation of phospholamban gene and dilated cardiomyopathy].

Phospholamban (PLB) is a prominent regulator of myocardial contractility and a reversible inhibitor of the cardiac sarcoplasmic reticulum Ca2+ ATPase activity. In normal cardiac muscles, phospholamban can be phosphorylated at distinct sites by various protein kinases and release its inhibition to sarcoplasmic reticulum Ca2+ ATPase. The studies of pedigrees have shown dilated cardiomyopathy (DCM) is related with mutation of PLB. The aim of present study is to investigate the relationship between mutation of PLB gene and DCM. Sixty patients with idiotic DCM were enrolled in present study. The clinical data were collected, including clinical symptoms, ECG and echocardiography. Peripheral blood samples of all these subjects were collected to extract genome DNA. The fragments of PLB gene were amplified by PCR and PCR fragment sequencing was performed to study weather mutation of phospholamban gene exists. phospholamban gene did not show any mutation in these patients. Most Chinese DCM patients may not be related with mutation of PLB gene.

Molecular cloning and functional expression of a gene encoding an antiarrhythmia peptide derived from the scorpion toxin.

From a cDNA library of Chinese scorpion Buthus martensii Karsch, full-length cDNAs of 351 nucleotides encoding precursors (named BmKIM) that contain signal peptides of 21 amino acid residues, a mature toxin of 61 residues with four disulfide bridges, and an extra Gly-Lys-Lys tail, were isolated. The genomic sequence of BmKIM was cloned and sequenced; it consisted of two exons disrupted by an intron of 1622 bp, the largest known in scorpion toxin genomes, inserted in the region encoding the signal peptide. The cDNA was expressed in Escherichia coli. The recombinant BmKIM was toxic to both mammal and insects. This is the first report that a toxin with such high sequence homology with an insect-specific depressant toxin group exhibits toxicity to mammals. Using whole cell patch-clamp recording, it was discovered that the recombinant BmKIM inhibited the sodium current in rat dorsal root ganglion neurons and ventricular myocytes and protected against aconitine- induced cardiac arrhythmia.