Establishment of the induced pluripotent stem cell line SJTUGHi002-A from a CNGA1-related recessive retinitis pigmentosa patient.

Retinitis pigmentosa (RP) is the most common inherited retinal diseases, characterized by photoreceptor cell death and retinal pigment epithelial atrophy. Mutations in cyclic nucleotide gated channel subunit alpha 1 (CNGA1) have been reported to cause retinitis pigmentosa. Here, we established the human induced pluripotent stem cell line (iPSC) SJTUGHi002-A, generated from peripheral blood mononuclear cells of a 36-year-old male RP patient, who carried a homozygous frameshift variant in CNGA1 gene (c.265delC; p.L89Ffs*4). The cell line can serve as a patient-derived disease model for exploring the pathogenesis and drug development of CNGA1-RP.

Identification of Cuproptosis-Related circRNA-miRNA-mRNA Network in Laser-Induced Choroidal Neovascularization Models and in Peripheral Blood Mononuclear Cells of Patients with Neovascular Age-Related Macular Degeneration.

INTRODUCTION: The aims of this study were to investigate the molecular alterations of cuproptosis-related genes and to construct the cuproptosis-related circular RNA (circRNA)-microRNA (miRNA)-mRNA networks in neovascular age-related macular degeneration (nAMD). METHODS: The transcriptional profiles of laser-induced choroid neovascularization (CNV) mouse models and nAMD patient samples were obtained from sequencing and from the GEO database (GSE146887), respectively. The expression levels of ten cuproptosis-related genes (FDX1, DLAT, LIAS, DLD, PDHB, MTF1, CDKN2A, GLS, LIPT1, and PDHA1) were extracted and verified in both mouse CNV models and patient peripheral blood mononuclear cells (PBMCs) samples. The cuproptosis-related circRNA-miRNA-mRNA network was further constructed based on miRNet database, the dataset GSE131646 of small RNA expression profile, and the dataset GSE140178 of circRNA expression profile in mouse CNV models. RESULTS: The significant upregulation of Cdkn2a and Mtf1 and the downregulation of other 5 cuproptosis-related genes were verified in the mouse CNV model, but only CDKN2A significantly upregulated in PBMCs of patients with nAMD. Four miRNAs were detected in the intersection between miRNet prediction and sequencing data: miR-129-5p, miR-129-2-3p, miR-182-5p, and miR-615-3p. There were 9 circRNAs at the intersection of hsa-miR-182-5p and hsa-miR-615-3p predictions, one circRNA predicted by hsa-miR-129-5p and GSE140178 (hsa-circASH1L), and one circRNA predicted by hsa-miR-182-5p and hsa-miR-615-3p (hsa-circNPEPPS). CONCLUSION: This study suggested the repression of cuproptosis in nAMD pathologies and constructed a cuproptosis-related network of 8 cuproptosis-related genes, 4 miRNAs, and 11 circRNAs.

The intestinal microbiota of a Risso’s dolphin (Grampus griseus): possible relationships with starvation raised by macro-plastic ingestion / La microbiota intestinal del delfín gris (Grampus griseus): posibles relaciones con la inanición provocada por la ingestión de macroplásticos

Ingesting marine plastics is increasingly common in cetaceans, but little is known about their potential effects. Here, by utilizing 16S rRNA gene sequencing, we profiled the intestinal bacterial communities of a stranded Risso’s dolphin (Grampus griseus) which died because of the ingestion of rubber gloves. In this study, we explored the potential relationships between starvation raised by plastic ingestion with the dolphin gut microbiota. Our results showed significant differences in bacterial diversity and composition among the different anatomical areas along the intestinal tract, which may be related to the intestinal emptying process under starvation. In addition, the intestinal bacterial composition of the Risso’s dolphin showed both similarity and divergence to that of other toothed whales, suggesting potential roles of both host phylogeny and habitat shaping of the cetacean intestinal microbiome. Perhaps, the microbiota is reflecting a potentially disordered intestinal microbial profile caused by the ingestion of macro-plastics which led to starvation. Moreover, two operational taxonomic units (0.17% of the total reads) affiliated with Actinobacillus and Acinetobacter lwoffii were detected along the intestinal tract. These bacterial species may cause infections in immunocompromised dolphins which are malnourished. This preliminary study profiles the intestinal microbiota of a Risso’s dolphin, and provides an additional understanding of the potential relationships between starvation raised by ingesting macro-plastics with cetacean gut microbiota.(AU)

A novel microdeletion of 517 kb downstream of the PAX6 gene in a Chinese family with congenital aniridia.

BACKGROUND: To identify the disease-causing gene in a Chinese family affected with congenital aniridia. METHODS: Patients underwent systematic ophthalmic examinations such as anterior segment photography, fundus photography, optical coherence tomography, and fundus fluorescein angiography. The proband was screened for pathogenic variants by whole exome sequencing (WES) and copy number variant (CNV) analysis. Real-time quantitative PCR (RT-qPCR) was applied to confirm the CNV results. Breakpoints were identified by long-range PCR followed by Sanger sequencing. RESULTS: All seven members of this Chinese family, including four patients and three normal individuals, were recruited for this study. All patients showed bilateral congenital aniridia with nystagmus, except the son of the proband, who presented with bilateral partial coloboma of the iris. A novel heterozygous deletion (chr11:31,139,019-31,655,997) containing the 3' regulatory enhancers of the PAX6 gene was detected in this family. We also reviewed the reported microdeletions downstream of PAX6 in patients with aniridia. CONCLUSIONS: We identified a novel microdeletion, 517 kb in size located about 133 kb downstream of the PAX6 gene, responsible for congenital aniridia in this Chinese family, which expands the spectrum of aniridia-associated mutations in PAX6.

Nomogram of uveal melanoma as prediction model of metastasis risk.

Background: Since the poor prognosis of uveal melanoma with distant metastasis, we intended to screen out possible biomarkers for uveal melanoma metastasis risk and establish a nomogram model for predicting the risk of uveal melanoma (UVM) metastasis. Methods: Two datasets of UVM (GSE84976, GSE22138) were selected. Data was analyzed by R language, CTD database and GEPIA. Results: The co-upregulated genes of two datasets, HTR2B, CHAC1, AHNAK2, and PTP4A3 were identified using a Venn diagram. These biomarkers are combined with clinical characteristics, and Lasso regression was conducted to filter the metastasis-related biomarkers. HTR2B, CHAC1, AHNAK2, PTP4A3, tumor thickness, and retinal detachment (RD) were selected to establish the nomogram. Conclusion: Our study provides a comprehensive predictive model and personalized risk estimation tool for assessment of 3-year metastasis risk of UVM with a better accuracy.

AAV-mediated base-editing therapy ameliorates the disease phenotypes in a mouse model of retinitis pigmentosa.

Base editing technology is an ideal solution for treating pathogenic single-nucleotide variations (SNVs). No gene editing therapy has yet been approved for eye diseases, such as retinitis pigmentosa (RP). Here, we show, in the rd10 mouse model, which carries an SNV identified as an RP-causing mutation in human patients, that subretinal delivery of an optimized dual adeno-associated virus system containing the adenine base editor corrects the pathogenic SNV in the neuroretina with up to 49% efficiency. Light microscopy showed that a thick and robust outer nuclear layer (photoreceptors) was preserved in the treated area compared with the thin, degenerated outer nuclear layer without treatment. Substantial electroretinogram signals were detected in treated rd10 eyes, whereas control treated eyes showed minimal signals. The water maze experiment showed that the treatment substantially improved vision-guided behavior. Together, we construct and validate a translational therapeutic solution for the treatment of RP in humans. Our findings might accelerate the development of base-editing based gene therapies.

Macrophage Sult2b1 promotes pathological neovascularization in age-related macular degeneration.

Disordered immune responses and cholesterol metabolism have been implicated in age-related macular degeneration (AMD), the leading cause of blindness in elderly individuals. SULT2B1, the key enzyme of sterol sulfonation, plays important roles in inflammation and cholesterol metabolism. However, the role and underlying mechanism of SULT2B1 in AMD have not been investigated thus far. Here, we report that SULT2B1 is specifically expressed in macrophages in choroidal neovascularization lesions. Sutl2b1 deficiency significantly reduced leakage areas and inhibited pathological angiogenesis by inhibiting M2 macrophage activation in vivo and in vitro. Mechanistically, loss of Sult2b1 activated LXRs and subsequently increased ABCA1 and ABCG1 (ABCA1/G1)-mediated cholesterol efflux from M2 macrophages. LXR inhibition (GSK2033 treatment) in Sult2b1 -/- macrophages reversed M2 polarization and decreased intracellular cholesterol capacity to promote pathological angiogenesis. In contrast to SULT2B1, STS, an enzyme of sterol desulfonation, protected against choroidal neovascularization development by activating LXR-ABCA1/G1 signalling to block M2 polarization. Collectively, these data reveal a cholesterol metabolism axis related to macrophage polarization in neovascular AMD.

SYVN1 Promotes STAT3 Protein Ubiquitination and Exerts Antiangiogenesis Effects in Retinopathy of Prematurity Development.

Purpose: SYVN1, a gene involved in endoplasmic reticulum-associated degradation, has been found to exert a protective effect by inhibiting inflammation in retinopathy. This study aimed to clarify whether SYVN1 is involved in the pathogenesis of retinopathy of prematurity (ROP) and its potential as a candidate for target therapy. Methods: Human retinal microvascular endothelial cells (hRMECs) and a mouse model of oxygen-induced retinopathy (OIR) were used to reveal the retinopathy development-associated protein expression and molecular mechanism. An adenovirus overexpressing SYVN1 or vehicle control was injected intravitreally at postnatal day 12 (P12), and the neovascular lesions were evaluated in retinal flatmounts with immunofluorescence staining, and hematoxylin and eosin staining at P17. Visual function was assessed by using electroretinogram (ERG). Results: Endogenous SYVN1 expression dramatically decreased in hRMECs under hypoxia and in ROP mouse retinas. SYVN1 regulated the signal transducer and activator of transcription 3 (STAT3)/vascular endothelial growth factor (VEGF) axis. SYVN1 overexpression promoted ubiquitination and degradation of STAT3, decreased the levels of phospho-STAT3, secretion of VEGF, and formation of neovascularization in hRMECs, which could be rescued by STAT3 activator treatment. In addition, SYVN1 overexpression prevented neovascularization and extended physiologic retinal vascular development in the retinal tissues of OIR mice without affecting retinal function. Conclusions: SYVN1 has a protective effect against OIR, and the molecular mechanisms are partly through SYVN1-mediated ubiquitination of STAT3 and the subsequent downregulation of VEGF. These findings strongly support our assumption that SYVN1 confers ROP resistance and may be a potentially novel pharmaceutical target against proliferative retinopathy.

Rapid and Sensitive Diagnosis of Leber Hereditary Optic Neuropathy Variants Using CRISPR/Cas12a Detection.

Leber hereditary optic neuropathy (LHON) is the most common maternally inherited mitochondrial disease, with >90% of cases harboring one of three point variants (m.3460G>A, m.11778G>A, and m.14484T>C). Rapid and sensitive diagnosis of LHON variants is urgently needed for early diagnosis and timely treatment after onset, which is currently limited. Herein, we adapted the Cas12a-based DNA detection platform for LHON mitochondrial variant diagnosis. Single-strand guide CRISPR RNAs and enzymatic recombinase amplification primers were first screened, the CRISPR/Cas12a system was then optimized with restriction enzymes, and finally compared with Sanger sequencing and next-generation sequencing (NGS) in multicenter clinical samples. This approach can be completed within 30 minutes using only one drop of blood and could reach a sensitivity of 1% of heteroplasmy. Among the 182 multicenter clinical samples, the CRISPR/Cas12a detection system showed high consistency with Sanger sequencing and NGS in both specificity and sensitivity. Notably, a sample harboring a de novo 3.78% m.11778G>A variant detected by NGS, but not by Sanger sequencing, was successfully confirmed using the CRISPR/Cas12a assay, which proved the effectiveness of our method. Overall, our CRISPR/Cas12a detection system provides an alternative for rapid, convenient, and sensitive detection of LHON variants, exhibiting great potential for clinical practice.

Acoustic Presence of Cetaceans in the Miaodao Archipelago, China.

Once an important cetacean habitat, the Miaodao Archipelago has been altered by human-induced disturbances over several decades. While cetacean diversity is known to have decreased, no recent data on species diversity around Miaodao are known to exist. Capitalizing on the high vocal activity of cetaceans, three passive acoustic surveys, including towed and stationary types, were undertaken to detect the presence of species-specific vocalizations in May 2021, October 2021, and July 2022, as most cetacean sightings occurred during May and August in recent years. The results revealed that the East Asian finless porpoise is the sole cetacean species that can be reliably observed around the archipelago, as no other species were detected. The acoustic data also revealed potentially clumped distributions of finless porpoises with some seasonal variation. While not acoustically detected during any of the surveys, humpback whales, minke whales, and killer whales have been visually sighted in the region. The lack of acoustic detection of these species suggests that they are likely to be temporary visitors to the region, or at least exhibit strong seasonality in their presence within the region. These new data provide the latest snapshot of cetacean presence around the Miaodao Archipelago that can help inform future research and conservation.

The intestinal microbiota of a Risso's dolphin (Grampus griseus): possible relationships with starvation raised by macro-plastic ingestion.

Ingesting marine plastics is increasingly common in cetaceans, but little is known about their potential effects. Here, by utilizing 16S rRNA gene sequencing, we profiled the intestinal bacterial communities of a stranded Risso's dolphin (Grampus griseus) which died because of the ingestion of rubber gloves. In this study, we explored the potential relationships between starvation raised by plastic ingestion with the dolphin gut microbiota. Our results showed significant differences in bacterial diversity and composition among the different anatomical areas along the intestinal tract, which may be related to the intestinal emptying process under starvation. In addition, the intestinal bacterial composition of the Risso's dolphin showed both similarity and divergence to that of other toothed whales, suggesting potential roles of both host phylogeny and habitat shaping of the cetacean intestinal microbiome. Perhaps, the microbiota is reflecting a potentially disordered intestinal microbial profile caused by the ingestion of macro-plastics which led to starvation. Moreover, two operational taxonomic units (0.17% of the total reads) affiliated with Actinobacillus and Acinetobacter lwoffii were detected along the intestinal tract. These bacterial species may cause infections in immunocompromised dolphins which are malnourished. This preliminary study profiles the intestinal microbiota of a Risso's dolphin, and provides an additional understanding of the potential relationships between starvation raised by ingesting macro-plastics with cetacean gut microbiota.

METTL3-mediated m6A modification of HMGA2 mRNA promotes subretinal fibrosis and epithelial-mesenchymal transition.

Subretinal fibrosis is a major cause of the poor visual prognosis for patients with neovascular age-related macular degeneration (nAMD). Myofibroblasts originated from retinal pigment epithelial (RPE) cells through epithelial-mesenchymal transition (EMT) contribute to the fibrosis formation. N6-Methyladenosine (m6A) modification has been implicated in the EMT process and multiple fibrotic diseases. The role of m6A modification in EMT-related subretinal fibrosis has not yet been elucidated. In this study, we found that during subretinal fibrosis in the mouse model of laser-induced choroidal neovascularization, METTL3 was upregulated in RPE cells. Through m6A epitranscriptomic microarray and further verification, high-mobility group AT-hook 2 (HMGA2) was identified as the key downstream target of METTL3, subsequently activating potent EMT-inducing transcription factor SNAIL. Finally, by subretinal injections of adeno-associated virus vectors, we confirmed that METTL3 deficiency in RPE cells could efficiently attenuate subretinal fibrosis in vivo. In conclusion, our present research identified an epigenetic mechanism of METTL3-m6A-HMGA2 in subretinal fibrosis and EMT of RPE cells, providing a novel therapeutic target for subretinal fibrosis secondary to nAMD.

Bifidobacterium promotes retinal ganglion cell survival by regulating the balance of retinal glial cells.

INTRODUCTION: Optic nerve injury is a leading cause of irreversible blindness worldwide. The retinal ganglion cells (RGCs) and their axons cannot be regenerated once damaged. Therefore, reducing RGC damage is crucial to prevent blindness. Accordingly, we aimed to investigate the potential influence of the gut microbiota on RGC survival, as well as the associated action mechanisms. METHODS: We evaluated the effects of microbiota, specifically Bifidobacterium, on RGC. Optic nerve crush (ONC) was used as a model of optic nerve injury. Vancomycin and Bifidobacterium were orally administered to specific pathogen-free (SPF) mice. RESULTS: Bifidobacterium promoted RGC survival and optic nerve regeneration. The administration of Bifidobacterium inhibited microglia activation but promoted Müller cell activation, which was accompanied by the downregulation of inflammatory cytokines and upregulation of neurotrophic factors and retinal ERK/Fos signaling pathway activation. CONCLUSIONS: Our study demonstrates that Bifidobacterium-induced changes in intestinal flora promote RGC survival. The protective effect of Bifidobacterium on RGC can be attributed to the inhibition of microglia activation and promotion of Müller cell activation and the secondary regulation of inflammatory and neurotrophic factors.

OUTER RETINAL TUBULATION IN BIETTI CRYSTALLINE DYSTROPHY ASSOCIATED WITH THE RETINAL PIGMENT EPITHELIUM ATROPHY.

PURPOSE: To determine the prognostic value of outer retinal tubulation (ORT) in the eyes of a Chinese cohort with Bietti crystalline dystrophy (BCD). METHODS: This retrospective, multicenter cohort study enrolled 42 patients with clinically and genetically diagnosed BCD. Eighty eyes with good-quality images of spectral domain optical coherence tomography were included. Demographic details and clinical data were collected. The characteristics of ORT, including prevalence, location, and morphologic characteristics were analyzed. RESULTS: Forty-two patients with BCD harbored potentially CYP4V2 disease-causing mutations. The mutation spectrum comprised 17 unique variants, 9 of which were novel. Fifty-two of these 80 eyes demonstrated evidence of ORT. The incidence of ORT is significantly higher in Stage 2 than other stages ( P < 0.001). ORT was mainly bilateral and located at the margin of the atrophic area of retinal pigment epithelium (RPE), and dynamically changed with the progressive RPE atrophy. The process of RPE atrophy was slower in eyes with ORT ( P = 0.017), with significantly longer intact RPE width in Stage 3 ( P = 0.024). Eyes with ORT had slower vision loss than eyes without ORT ( P = 0.044). CONCLUSION: ORT may be a sign of the onset of RPE atrophy in early-stage BCD and may suggest less risk of rapid progression in late-stage BCD.

CircRNA Uxs1/miR-335-5p/PGF axis regulates choroidal neovascularization via the mTOR/p70 S6k pathway.

Age-related macular degeneration (AMD) is one of the leading causes of irreversible blindness in the elderly population. Neovascular AMD is the late stage, characterized by choroidal neovascularization (CNV). Non-coding RNAs have been implicated in CNV; however, the role of circular RNAs (circRNAs) has not yet been elucidated. Herein, we comprehensively investigated circRNA profiles in laser-induced CNV mouse models and patient specimens. A novel circRNA, circRNA Uxs1, was identified, and its function in CNV regulation was investigated in the present study. CircRNA Uxs1 was consistently upregulated in CNV patient specimens and CNV mouse models. Knockdown of circRNA Uxs1 interrupted the tube formation, migration, and proliferation of endothelial cells in vitro. Silencing circRNA Uxs1 in vivo alleviated neovascularization formation, as shown by the decreased size of laser spots. Mechanistically, circRNA Uxs1 functioned by binding to miR-335-5p, which further upregulated the expression of placental growth factor (PGF) gene and activated the mammalian target of rapamycin/p70 S6 Kinase (mTOR/p70 S6k) pathway. By subretinal injections of adeno-associated virus (AAV), we demonstrated the anti-angiogenic function of circRNA Uxs1 knockdown in vivo. In conclusion, circRNA Uxs1 promoted CNV by sponging miR-335-5p, which stimulated PGF expression and subsequently activated the mTOR/p70 S6k pathway. Therefore, circRNA Uxs1 may serve as a promising therapeutic target for CNV.

Comprehensive analysis of the PRPF31 gene in retinitis pigmentosa patients: Four novel Alu-mediated copy number variations at the PRPF31 locus.

Retinitis pigmentosa (RP) is a monogenic disease characterized by irreversible degeneration of the retina. PRPF31, the second most common causative gene of autosomal dominant RP, frequently harbors copy number variations (CNVs), but the underlying mechanism is unclear. In this study, we summarized the phenotypic and genotypic characteristics of 18 RP families (F01-F18) with variants in PRPF31. The prevalence of PRPF31 variants in our cohort of Chinese RP families was 1.7% (18/1024). Seventeen different variants in PRPF31 were detected, including eight novel variants. Notably, four novel CNVs encompassing PRPF31, with a proportion of 22.2% (4/18), were validated to harbor gross deletions involving Alu/Alu-mediated rearrangements (AAMRs) in the same orientation. Among a total of 12 CNVs of PRPF31 with breakpoints mapped on nucleotide-resolution, 10 variants (83.3%) were presumably mediated by Alu elements. Furthermore, we described the correlation between the genotypes and phenotypes in PRPF31-related RP. Our findings expand the mutational spectrum of the PRPF31 gene and provide strong evidence that Alu elements of PRPF31 probably contribute to the susceptibility to genomic rearrangement in this locus.

Biogeographic patterns of potential pathogenic bacteria in the middle and lower reaches of the Yangtze River as well as its two adjoining lakes, China.

Understanding the distribution patterns and shaping factors of bacterial pathogens in aquatic ecosystems, especially in natural waters, are critical to the control of pathogen transmission. In this study, using 16S rRNA gene amplicon sequencing, we explored the composition and biogeographic dynamics of potential bacterial pathogens in the middle and lower reaches of the Yangtze River, as well as its two vast adjoining lakes (Dongting Lake and Poyang Lake). The pathogen community belonged to 12 potential pathogenic groups, with "intracellular parasites," "animal parasites or symbionts" and "human pathogens all" occupying 97.5% in total. The potential pathogen community covered seven phyla with Proteobacteria (69.8%) and Bacteroidetes (13.5%) the most predominant. In addition, 53 genera were identified with Legionella (15.2%) and Roseomonas (14.2%) the most dominant. The average relative abundance, alpha diversity and microbial composition of the potential bacterial pathogens exhibited significant biogeographical variations among the different sections. An in-depth analysis reflected that environmental variables significantly structured the potential bacterial pathogens, including water physiochemical properties (i.e., chlorophyll-a, total nitrogen and transparency), heavy metals (i.e., As and Ni), climate (i.e., air temperature) and land use type (i.e., waters). Compared to the overall bacterial community which was composed of both pathogenic and non-pathogenic bacteria, the pathogen community exhibited distinct microbial diversity patterns and shaping factors. This signifies the importance of different variables for shaping the pathogen community. This study represents one attempt to explore pathogen diversity patterns and their underlying drivers in the Yangtze River, which provides a foundation for the management of pathogenic bacteria.

Targeting C3b/C4b and VEGF with a bispecific fusion protein optimized for neovascular age-related macular degeneration therapy.

Antiangiogenesis therapies targeting vascular endothelial growth factor (VEGF) have revolutionized the treatment of neovascular ocular diseases, including neovascular age-related macular degeneration (nAMD). Compelling evidence has implicated the vital role of complement system dysregulation in AMD pathogenesis, implying it as a potential therapeutic strategy for geographic atrophy in dry AMD and to enhance the efficacy of anti-VEGF monotherapies in nAMD. This study reports the preclinical assessment and phase 1 clinical outcomes of a bispecific fusion protein, efdamrofusp alfa (code: IBI302), which is capable of neutralizing both VEGF isoforms and C3b/C4b. Efdamrofusp alfa showed superior efficacy over anti-VEGF monotherapy in a mouse laser-induced choroidal neovascularization (CNV) model after intravitreal delivery. Dual inhibition of VEGF and the complement activation was found to further inhibit macrophage infiltration and M2 macrophage polarization. Intravitreal efdamrofusp alfa demonstrated favorable safety profiles and exhibited antiangiogenetic efficacy in a nonhuman primate laser-induced CNV model. A phase 1 dose-escalating clinical trial (NCT03814291) was thus conducted on the basis of the preclinical data. Preliminary results showed that efdamrofusp alfa was well tolerated in patients with nAMD. These data suggest that efdamrofusp alfa might be effective for treating nAMD and possibly other complement-related ocular conditions.

Biofilm formation, antimicrobial assay, and toxin-genotypes of Clostridium perfringens type C isolates cultured from a neonatal Yangtze finless porpoise.

This is a culture-dependent study with the objective of pure culturing and characterizing pathogenic bacteria from the blowhole, lung, stomach and fecal samples of a neonatal crucially endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) that died 27 days after birth. Bacteria were inoculated using a swab onto blood and MacConkey agar plates and representative isolates were identified through 16S rRNA gene sequence analysis. A total of three Clostridium perfringens type C strains from the fecal samples were isolated. Toxin genes, including cpa, cpb and cpb2, were detected by PCR amplification, whereas the etx, iap and cpe genes were not detected. Biofilm formation of the three strains was then examined. Only one strain was capable of biofilm formation. In addition, isolates showed strong resistance against the antibiotics amikacin (3/3), erythromycin (1/3), gentamicin (3/3), streptomycin (3/3), and trimethoprim (3/3), while sensitivity to ampicillin (3/3), bacitracin (3/3), erythromycin (2/3), penicillin G (3/3), and tetracycline (3/3). The results suggested C. perfringens type C could have contributed to the death of this neonatal porpoise.