DNAJA1 regulates protein ubiquitination and is essential for spermatogenesis in the testes of mice and rats.

DNAJA1 is a member of type I DnaJ proteins, which is essential for spermatogenesis and male fertility. However, its expression pattern in the testes and its impact on spermatogenesis remains unclear. Our study aimed to elucidate the mechanism of action of DNAJA1. We employed DNAJA1 knockout mice in this study. Western blotting and immunofluorescence analysis were conducted to determine the protein abundance of DNAJA1 in testes at various developmental stages. Our results revealed that DNAJA1 is predominantly expressed in the testes, and its knockout leads to complete infertility in male mice. We observed that DNAJA1 protein levels increased on postnatal days 14, 21, and 28, peaking on postnatal day 35 in mice. Immunofluorescence staining indicated that DNAJA1 expression varies across different stages of the spermatogenesis cycle. Additionally, DNAJA1 was absent in epididymal sperm. In early- and mid-stage tubules, DNAJA1 protein distribution was co-localized with residual bodies in elongating spermatids. Furthermore, we found that DNAJA1 knockout significantly reduced protein polyubiquitination in the testis. Analysis of the GEO database showed that DNAJA1 levels were significantly decreased in semen samples from subjects with teratozoospermia, asthenozoospermia, and impaired spermatogenesis. Our findings suggest that DNAJA1 is an essential protein for spermatogenesis, and its deletion reduces protein polyubiquitination in the testis, ultimately resulting in infertility and spermatogenesis defects.

Celastrol reduces lung inflammation induced by multiwalled carbon nanotubes in mice via NF-κb-signaling pathway.

Multiwalled carbon nanotubes (MWCNTs) have numerous applications in the field of carbon nanomaterials. However, the associated toxicity concerns have increased significantly because of their widespread use. The inhalation of MWCNTs can lead to nanoparticle deposition in the lung tissue, causing inflammation and health risks. In this study, celastrol, a natural plant medicine with potent anti-inflammatory properties, effectively reduced the number of inflammatory cells, including white blood cells, neutrophils, and lymphocytes, and levels of inflammatory cytokines, such as IL-1ß, IL-6, and TNF-α, in mice lungs exposed to MWCNTs. Moreover, celastrol inhibited the activation of the NF-κB-signaling pathway. This study confirmed these findings by demonstrating comparable reductions in inflammation upon exposure to MWCNTs in mice with the deletion of NF-κB (P50-/-). These results indicate the utility of celastrol as a promising pharmacological agent for preventing MWCNT-induced lung tissue inflammation.

Medium composition optimization and characterization of polysaccharides extracted from Ganoderma boninense along with antioxidant activity.

Ganoderma is a well-known medicinal macrofungal genus, of which several species have been thoroughly studied from the medicinal perspective, but most species are rarely involved in. In this study, we focus on the polysaccharides extracted from Ganoderma boninense and their antioxidant activity. Ganoderma boninense is a serious pathogen of oil palms that are cultivated commercially in Southeast Asia. Response surface methodology was conducted to optimize the liquid medium composition, and the mycelia biomass reached 7.063 g/L, that is, 1.4-fold compared with the seed medium. The crude and purified polysaccharides extracted from the fermentation broth showed well 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging abilities, and the scavenging abilities of purified polysaccharides reached 94.47 % and 99.88 %, respectively. Six fractions of polysaccharides were extracted and purified from fruiting bodies, mycelia and fermentation broth separately with the elution buffers of distilled water and 0.1 M NaCl solution. Generally, the polysaccharides from fruiting bodies showed stronger protective effect on H2O2-induced HepG2 cell oxidative damage than other fractions. A total of five to seven monosaccharides were identified in the six fractions of polysaccharides. The correlation analysis revealed that the content of fucose was significantly correlated with the antioxidant activity of polysaccharides, while xylose showed negative correlation results. In summary, the polysaccharides from G. boninense have a potential to be used as natural antioxidants.

Understanding of Co-boiling between Organic Contaminants and Water during Thermal Remediation: Effects of Nonequilibrium Heat and Mass Transport.

In situ thermal desorption (ISTD) provides an efficient solution to remediation of soil and groundwater contaminated with nonaqueous phase liquids (NAPLs). Establishing a relationship between the subsurface temperature rise and NAPL removal is significant to reduce energy consumption of ISTD. However, the co-boiling phenomenon between NAPL and water poses a great challenge in developing this relationship due to the nonequilibrium heat and mass transport effects. We performed a systematic experimental investigation into the local temperature rise patterns at different distances from a NAPL pool and under different degrees of superheat by selecting four representative NAPLs (i.e., trichloroethylene, tetrachlorethylene, n-hexane, and n-octane) according to their density and boiling point relative to water. The patterns of temperature rise indicated that the underground temperature field can be divided into three zones: the zone of local thermal equilibrium, the nonequilibrium zone affected by co-boiling, and the zone unaffected by co-boiling. We developed a pattern-recognition-based approach, which considers the effects of local heat and mass transport to establish a qualitative correlation between the temperature rise and NAPL removal. Our results give deeper insights into the understanding of subsurface temperatures in ISTD practice, which can serve as the guideline for more accurate and sustainable remediation.

Drought stress in rice: morpho-physiological and molecular responses and marker-assisted breeding.

Rice (Oryza Sativa L.) is an essential constituent of the global food chain. Drought stress significantly diminished its productivity and threatened global food security. This review concisely discussed how drought stress negatively influenced the rice's optimal growth cycle and altered its morpho-physiological, biochemical, and molecular responses. To withstand adverse drought conditions, plants activate their inherent drought resistance mechanism (escape, avoidance, tolerance, and recovery). Drought acclimation response is characterized by many notable responses, including redox homeostasis, osmotic modifications, balanced water relations, and restored metabolic activity. Drought tolerance is a complicated phenomenon, and conventional breeding strategies have only shown limited success. The application of molecular markers is a pragmatic technique to accelerate the ongoing breeding process, known as marker-assisted breeding. This review study compiled information about quantitative trait loci (QTLs) and genes associated with agronomic yield-related traits (grain size, grain yield, harvest index, etc.) under drought stress. It emphasized the significance of modern breeding techniques and marker-assisted selection (MAS) tools for introgressing the known QTLs/genes into elite rice lines to develop drought-tolerant rice varieties. Hence, this study will provide a solid foundation for understanding the complex phenomenon of drought stress and its utilization in future crop development programs. Though modern genetic markers are expensive, future crop development programs combined with conventional and MAS tools will help the breeders produce high-yielding and drought-tolerant rice varieties.

Characteristics of reflux and gastric electrical activity in gastroesophageal reflux disease with ineffective esophageal motility.

OBJECTIVES: The impact of ineffective esophageal motility (IEM) on gastroesophageal reflux disease (GERD) remains unknown, and abnormal esophageal motility often coexists with abnormal gastric motility. We aimed to investigate the role of IEM in GERD and its relationship with gastric electrical activity. METHODS: Patients diagnosed as GERD based on GERD-questionnaire score ≥8 in our hospital from January 2020 to June 2022 were included. All patients underwent 24-h multichannel intraluminal impedance-pH monitoring, high-resolution manometry, and electrogastrogram and were categorized into the normal esophageal motility (NEM) and IEM groups, respectively. Reflux characteristics and gastric electric activity were compared between the two groups, and the correlation between gastric electric activity and reflux was analyzed. RESULTS: Acid exposure time, total reflux episodes, and DeMeester score in the IEM group were higher than those in the NEM group. Distal mean nocturnal baseline impedance was significantly lower in the IEM group. Compared with the NEM group, the power ratio (PR) of fundus, antrum and pylorus and premeal and postmeal normal wave ratio of antrum were significantly lower in IEM. The total reflux episodes were negatively correlated with the PR of fundus and pylorus, and the DeMeester score was negatively correlated with the PR of corpus and pylorus. CONCLUSIONS: IEM may lead to increased reflux, resulting in esophageal mucosal damage. There may be consistency between abnormal esophageal motility and gastric motility.

Celastrol alleviates oxidative stress induced by multi-walled carbon nanotubes through the Keap1/Nrf2/HO-1 signaling pathway.

Multi-walled carbon nanotubes (MWCNTs) mainly induce oxidative stress through the overproduction of reactive oxygen species (ROS), which can lead to cytotoxicity. Celastrol, a plant-derived compound, can exert antioxidant effects by reducing ROS production. Our results indicated that exposure to MWCNTs decreased cell viability and increased ROS production. Nrf2 knockdown (kd) led to increased ROS production and enhanced MWCNT-induced cytotoxicity. Keap1-kd led to decreased ROS production and attenuated cytotoxicity. Treatment with celastrol significantly decreased ROS production and promoted Keap1 protein degradation through the lysosomal pathway, thereby enhancing the translocation of Nrf2 from the cytoplasm to the nucleus and increasing HO-1 expression. The in vivo results showed that celastrol could alleviate the inflammatory damage of lung tissues, increase the levels of the antioxidants, GSH and SOD, as well as promote the expression of the antioxidant protein, HO-1 in MWCNT-treated mice. Celastrol can alleviate MWCNT-induced oxidative stress through the Keap1/Nrf2/HO-1 signaling pathway.

Clinical prospective study of Gallium 68 (68Ga)-labeled fibroblast-activation protein inhibitor PET/CT in the diagnosis of biliary tract carcinoma.

PURPOSE: This study is to investigate the [68Ga]Ga-DOTA-FAPI PET/CT diagnosis performance in biliary tract carcinoma (BTC) and analyze the association between [68Ga]Ga-DOTA-FAPI PET/CT and clinical indexes. METHODS: A prospective study (NCT05264688) was performed between January 2022 and July 2022. Fifty participants were scanned using [68Ga]Ga-DOTA-FAPI and [18F]FDG PET/CT and acquired pathological tissue. We employed the Wilcoxon signed-rank test to compare the uptake of [68Ga]Ga-DOTA-FAPI and [18F]FDG, and the McNemar test was used to compare the diagnostic efficacy between the two tracers. Spearman or Pearson correlation was used to assess the association between [68 Ga]Ga-DOTA-FAPI PET/CT and clinical indexes. RESULTS: In total, 47 participants (mean age 59.09 ± 10.98 [range 33-80 years]) were evaluated. The [68Ga]Ga-DOTA-FAPI detection rate was greater than [18F]FDG in primary tumors (97.62% vs. 85.71%), nodal metastases (90.05% vs. 87.06%), and distant metastases (100% vs. 83.67%). The uptake of [68Ga]Ga-DOTA-FAPI was higher than [18F]FDG in primary lesions (intrahepatic cholangiocarcinoma, 18.95 ± 7.47 vs. 11.86 ± 0.70, p = 0.001; extrahepatic cholangiocarcinoma, 14.57 ± 6.16 vs. 8.80 ± 4.74, p = 0.004), abdomen and pelvic cavity nodal metastases (6.91 ± 6.56 vs. 3.94 ± 2.83, p < 0.001), and distant metastases (pleural, peritoneum, omentum, and mesentery, 6.37 ± 4.21 vs. 4.50 ± 1.96, p = 0.01; bone, 12.15 ± 6.43 vs. 7.51 ± 4.54, p = 0.008). There was a significant correlation between [68Ga]Ga-DOTA-FAPI uptake and fibroblast-activation protein (FAP) expression (Spearman r = 0.432, p = 0.009), carcinoembryonic antigen (CEA) (Pearson r = 0.364, p = 0.012), and platelet (PLT) (Pearson r = 0.35, p = 0.016). Meanwhile, a significant relationship between [68Ga]Ga-DOTA-FAPI metabolic tumor volume and carbohydrate antigen199 (CA199) (Pearson r = 0.436, p = 0.002) was confirmed. CONCLUSION: [68Ga]Ga-DOTA-FAPI had a higher uptake and sensitivity than [18F]FDG in the diagnosis of BTC primary and metastatic lesions. The correlation between [68Ga]Ga-DOTA-FAPI PET/CT indexes and FAP expression, CEA, PLT, and CA199 were confirmed. TRIAL REGISTRATION: clinicaltrials.gov: NCT 05,264,688.

Visible Light-Induced Cross-Dehydrocoupling of 3-Cyanocoumarins with Unactivated Aliphatic Aldehydes Enables Access to 4-Acylated Coumarins.

We report visible light-induced cross-dehydrocoupling of 3-cyanocoumarins with unactivated aliphatic aldehydes for the direct synthesis of 4-acylated coumarins. Inexpensive and readily available (n-Bu)4NBr was used as a precursor of the hydrogen atom transfer (HAT) catalyst and [Ir(ppy)2(dtbbpy)PF6] as a photocatalyst. A variety of aldehydes including linear, branched, cyclic, and α,ß-unsaturated aliphatic aldehydes were suitable for this reaction yielding the desired acylated coumarin derivatives in 41-98% yields. This method provides a mild, atom-economical, and environmentally friendly synthetic route for the direct acylation of 3-cyanocoumarins. This is the first example so far of C-4 aliphatic acylation of coumarins.

Risk factors for the long-term prognosis and recurrence of HIV-negative cytomegalovirus retinitis in North China.

AIM: To demonstrate the clinical features, the risk factors, the visual prognosis and the recurrence of cytomegalovirus (CMV) retinitis (CMVR) in HIV-negative patients. METHODS: HIV-negative patients with CMVR were involved in this study. Best corrected visual acuity (BCVA), intraocular pressure (IOP), CMV-DNA load in aqueous and/or serum samples, treatment, follow-up time, recurrence and complications were recorded. Ocular characteristics were evaluated by fundus photographs. Association between ocular factors and visual prognosis were analyzed by regression analysis. RESULTS: Twenty-five eyes of 16 patients were included. All 25 eyes underwent intravitreal injections of anti-viral agents. The mean logMAR BCVA improved from 0.94±0.98 (0.98-0.78) initially to 0.77±0.73 (0.82-0.68) at last visit, but not significantly. After antiviral treatment, the aqueous CMV DNA load significantly reduced to (3.42±1.47)×102 copies/mL (P=0.001), compared with (2.51±3.11)×105 copies/mL at baseline. Macular involvement (R 2=0.475, P=0.049) and initial visual acuity (R 2=0.475, P=0.017) were significantly associated with the poor visual prognosis (BCVA<20/400). The extent of retinal lesions (R 2=0.064, P=0.04) was significant associated with the risk of recurrence of CMVR. CONCLUSION: Intravitreal injection of anti-viral agents offers a safe and effective treatment for CMVR. Macular involvement and initial visual acuity significantly associate with visual prognosis. The extent of retinal lesions is significantly associated with the recurrence of CMVR. These ocular factors can be used as predictive risk factors for long term visual prognosis in HIV-negative CMVR patients.

Vascular toxicity of multi-walled carbon nanotubes targeting vascular endothelial growth factor.

Multiwalled carbon nanotubes (MWCNTs) are currently widely used and are expected to be used as drug carriers and contrast agents in clinical practice. Previous studies mainly focused on their lung toxicity; therefore, their effects on the vascular endothelium are unclear. In this study, a human angiogenesis array was used to determine the effect of MWCNTs on the expression profile of angiogenic factors in endothelial cells and to clarify the role of vascular endothelial growth factor (VEGF) in MWCNT-induced endothelial cell injury at the cellular and animal levels. The results indicated that MWCNTs (20-30 nm and 30-50 nm) could enter endothelial cells and disrupt human umbilical vein endothelial cell (HUVECs) activity in a concentration-dependent manner. MWCNTs disrupted the tube formation ability and cell migration function of HUVECs. The results from a Matrigel Plug experiment in mice showed that angiogenesis in the MWCNT experimental group was significantly reduced. The results of a protein chip analysis indicated that VEGF expression in the MWCNT treatment group was decreased, a finding that was validated by ELISA results. The protein expression levels of AKT and eNOS in the MWCNT treatment group were significantly decreased; the administration of recombinant VEGF significantly alleviated the migration ability and tube formation ability of endothelial cells injured by MWCNTs, upregulated the protein expression of AKT and eNOS, and increased the number of neovascularization in mice in the MWCNT treatment group. This study demonstrated that MWCNTs affect angiogenesis via the VEGF-Akt-eNOS axis which can be rescued by VEGF endothelial treatment.

Alloexidiopsis gen. nov., A Revision of Generic Delimitation in Auriculariales (Basidiomycota).

Auriculariales is a fungal order with highly diverse morphological traits of basidiomes, which partially leads to a poor understanding of its taxonomic system at the generic level. To identify our recently collected specimens of Auriculariales to a species level, we perform a comprehensive phylogenetic analysis of the generic relationships in Auriculariales. In association with morphological characteristics, a new genus Alloexidiopsis belonging to Auriculariaceae is erected with two new species, namely, A. australiensis and A. schistacea. Moreover, Exidiopsis calcea separated from the generic type E. effusa and Heteroradulum niveum and H. yunnanense recently inaccurately described as members of Heteroradulum are recovered in the clade of Alloexidiopsis. These three species are thus transferred to this new genus. One collection of Exidiopsis grisea also falls in the clade of Alloexidiopsis, whereas another collection of this species is separated far from Alloexidiopsis and E. effusa. Since we have no collection to confirm the species identity of E. grisea, its generic position is uncertain. The main taxonomic morphological differences among Alloexidiopsis and related corticioid genera in Auriculariales are summarized. A key to all the five accepted species of Alloexidiopsis is provided. As two unnamed lineages exist in Alloexidiopsis besides the abovementioned five species, it is assumed that more new species will be revealed from this genus under its current circumscription.

Redelimitation of Heteroradulum (Auriculariales, Basidiomycota) with H.australiense sp. nov.

Auriculariales accommodates species with diverse basidiomes and hymenophores. From morphological and phylogenetic perspectives, we perform a taxonomic study on Heteroradulum, a recently validated genus within the Auriculariales. The genus Grammatus is merged into Heteroradulum, and thus its generic type G.labyrinthinus is combined with Heteroradulum and G.semis is reaccepted as a member of Heteroradulum. Heteroradulumaustraliense is newly described on the basis of three Australian specimens. Heteroradulumyunnanense is excluded from this genus and its taxonomic position at the generic level is considered uncertain. Accordingly, the circumscription of Heteroradulum is re-delimited and the concept of this genus is adjusted by including irpicoid to poroid hymenophores and a hyphal system with clamp connections or simple septa. A key to all nine accepted species of Heteroradulum is presented.

Pyruvate Kinase M2 Mediates Glycolysis Contributes to Psoriasis by Promoting Keratinocyte Proliferation.

Psoriasis is characterized by keratinocyte proliferation and immune cell infiltration. M2 isoform of pyruvate kinase (PKM2) was reported to have an important role in cell proliferation, which is a rate-limiting enzyme that regulates the final step of glycolysis. However, how PKM2 regulates cell metabolism and proliferation in psoriatic keratinocytes is still poorly understood. Interestingly, we found that PKM2 was highly expressed in psoriatic epidermis from patients and mouse models. PKM2 overexpression promoted keratinocyte glycolytic metabolism while knockdown inhibited keratinocyte proliferation and glycolysis. Mice lacking PKM2 specifically in keratinocytes, pharmacological inhibition of PKM2 or glycolysis inhibited keratinocyte proliferation and showed obvious remission in an imiquimod-induced psoriatic mouse model. Moreover, the inhibitor of the EGF-receptor blocked EGF-stimulated PKM2 expression and glycolysis in keratinocytes. We identify PKM2 as an upregulated gene in psoriasis. PKM2 is essential in keratinocyte over-proliferation and may represent a therapeutic target for psoriasis.

Nucleotide sequences of the infectious DNA clones of two mink enteritis virus isolates exhibit the diversity of the terminal palindromic sequences and predicted secondary structures.

In this study, the infectious RF-DNA clones of two mink enteritis viruses, MEV-SD1 and MEV-SD7, were constructed, which generated progeny virions and seemed to contain an almost or completely full-length genome. The genomes of MEV-SD1 and MEV-SD7 were 5162 bp and 5113 bp in length, respectively. The genomic organizations of MEV-SD1 and MEV-SD7 were similar to that of the other carnivore parvoviruses. The 3'-UTR of the virion strand of MEV-SD1 and MEV-SD7 were 311 bp and 313 bp in length, respectively, containing a 208 bp palindromic sequence assuming Y-shaped configurations. Interestingly, the difference of the 3' palindromic sequences between MEV-SD1 and MEV-SD7 resulted in the orientation inversion of the hairpin ears. And the 5'-UTRs of MEV-SD1 and MEV-SD7 were 582 bp and 531 bp, respectively, containing a 198 bp palindromic sequence assuming U-shaped configurations, a triplet mismatch (5'-TAC-3') in the center of the duplex stem and a triplet mismatch (5'-AGA-3') forming a small asymmetric bubble. The findings demonstrated that the genomic termini of the carnivore parvoviruses showed the diversity in length, base composition, and predicted secondary structure.

Endothelium-Specific GTP Cyclohydrolase I Overexpression Restores Endothelial Function in Aged Mice.

This study tested the hypothesis that endothelium-specific GTP cyclohydrolase I (GTPCH I) overexpression (Tg-GCH) restores age-associated endothelial dysfunction in vivo. Aortic GTPCH I expression and serum nitric oxide (NO) release were measured in young and aged mice. Aortic rings from young and aged wild-type (WT) mice and aged Tg-GCH mice were suspended for isometric tension recording. A hind limb ischemia model was used to measure blood flow recovery. Aged mice showed reduced GTPCH I expression in the aorta and decreased NO levels in serum. Compared with aged WT mice, Tg-GCH significantly elevated NO levels in serum in aged Tg-GCH mice, restored the impaired aortic relaxation in response to acetylcholine, and significantly elevated aortic constriction in response to L-NAME. Importantly, aged Tg-GCH mice displayed a significant increase in blood flow recovery compared with aged WT mice. GTPCH I reduction contributes to aging-associated endothelial dysfunction, which can be retarded by Tg-GCH.

Molecular characteristics of H9N2 influenza viruses isolated from farmed raccoon dogs and arctic foxes in China.

In this study, eight H9N2 IAVs were isolated from infected diseased, farmed raccoon dogs and arctic foxes. Eight genes shared 98.6%-100% identity among the isolates possessing a PSRSSR/GL motif at the HA cleavage site, which is same as the motif of G1 and Y280 lineages of H9N2 IAVs. The phylogenetic analysis showed that the HA genes of the eight isolates clustered with Y280-like viruses, whereas the NA genes belonged to F/98-like sublineage. Interestingly, the NS, NP, PB2 and PA genes of the isolates were closely related to H7N9 IAVs. This is the first evidence for isolation of H9N2 IAVs from raccoon dogs and arctic foxes. Raccoon dogs and arctic foxes potentially serve as an intermediate host for influenza viruses with pandemic potential toward other animals due to co-expression of both SA α-2,6-Gal and SA α-2,3-Gal receptors in a wide range of their tissues.

Triiodothyronine levels were positively correlated with opening of collateral circulation in cerebral infarction patients with large artery atherosclerosis.

INTRODUCTION: Non-thyroidal illness syndrome (NTIS) is one of the signs for poor prognosis of cerebral infarction (CI), but its risk factors had never been explored. In this study, we analyzed the potential effect of collateral circulation on prognosis prediction of triiodothyronine for large artery atherosclerosis cerebral infarction (LAA-CI) patients. MATERIAL AND METHODS: Clinical data of CI patients between 2012 and 2014 were collected. Imaging inspection was used for determining TOAST classification and evaluating collateral circulation. One-year follow-up was conducted for mRS score by telephone. RESULTS: T3 level in the NTIS group (p = 0.001) was significantly decreased while TSH level (p < 0.001) was increased. Patients in the NTIS group had a poorer prognosis (p = 0.008) and the main reason was the high mortality (p = 0.002). NTIS predicted poor collateral circulation (p = 0.026) and good collateral circulation tended to be less likely concomitant with NTIS (p = 0.001). Logistic regression analysis showed that triiodothyronine concentrations (OR = 4.760, 95% CI: 1.981-11.456, p < 0.001) were positively correlated with but advanced age (OR = 0.756, 95% CI: 0.645-0.886, p = 0.001) negatively with opening of collateral circulation. CONCLUSIONS: Poor opening of collateral circulation was likely to mediate the prediction of NTIS for prognosis of LAA-CI patients.

Co-infection of H9N2 influenza virus and Pseudomonas aeruginosa contributes to the development of hemorrhagic pneumonia in mink.

Influenza A virus (IAV) and bacteria co-infection can influence the host clinical conditions. Both H9N2 IAV and Pseudomonas aeruginosa (P. aeruginosa) are potential pathogens of respiratory diseases in mink. In this study, to clarify the effects of H9N2 IAV and P. aeruginosa co-infections on hemorrhagic pneumonia in mink, we carried out to establish the mink models of the two-pathogen co-infections in different orders. Compared with the single infections with H9N2 IAV or P. aeruginosa, the mink co-infected with H9N2 IAV and P. aeruginosa showed severe respiratory diseases, and exacerbated histopathological lesions and more obvious apoptosis in the lung tissues. H9N2 IAV shedding and viral loads in the lungs of the mink co-infected with H9N2 IAV and P. aeruginosa were higher than those in the mink with single H9N2 IAV infection. Furthermore, the clearance of P. aeruginosa in the co-infected mink lungs was delayed. In addition, the anti-H9N2 antibody titers in mink with P. aeruginosa co-infection following H9N2 IAV infection were significantly higher than those of the other groups. This implied that H9N2 IAV and P. aeruginosa co-infection contributed to the development of hemorrhagic pneumonia in mink, and that P. aeruginosa should play a major role in the disease. The exact interaction mechanism among H9N2 IAV, P. aeruginosa and the host needs to be further investigated.