Metabolic disturbance of short- and medium-chain chlorinated paraffins to zebrafish larva.

Chlorinated paraffins (CPs) are widely produced chemicals. Short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) were listed as Persistent Organic Pollutants (POPs) and candidate POPs under the Stockholm Convention, respectively. The present study explored the developmental toxicity and metabolic disruption caused by SCCPs and MCCPs in zebrafish (Danio rerio) larvae. CPs exposure at environmentally relevant levels caused no obvious phenotypic changes with zebrafish larvae except that the body length shortening was observed after exposure to CPs at 1-200 µg/L for 7 day post fertilization. A further metabolomic approach was conducted to explore the early biological responses of developmental toxicity induced by CPs at low dose (1, 5, and 10 µg/L). The results of metabolic disorder, pathway analysis and chronic values indicated that, compared with SCCPs, MCCPs exhibited more risks to zebrafish larvae at low doses. Lipid metabolism was markedly affected in SCCPs exposure group, whereas MCCPs primarily disturbed lipid metabolism, amino acid, and nucleotide metabolisms. Compare with SCCPs, the relatively higher lipid solubility, protein affinity and metabolic rate of MCCPs can probably explain why MCCP-mediated metabolic disruption was significantly higher than that of SCCP. Notably, SCCPs and MCCPs have the same potential to cause cancer, but no evidence indicates the mutagenicity. In summary, our study provides insight into the potential adverse outcome for SCCP and MCCP at low doses.

Ecotoxicity and Risk to Zooplankton of a Novel Insecticide Used in Rice Paddies in a Simulated Ecosystem.

Diamide insecticides are widely used in rice paddies and pose a potential threat to aquatic organisms. However, the risk research related to their application in major rice-producing areas is very limited, especially mesocosm research to simulate the impact on aquatic ecosystems of long-term exposure, as well as exposure analysis based on local models and local scenarios. To assess potential risks from a novel diamide insecticide (tetrachlorantraniliprole) to aquatic nontarget organisms in the field over long-term exposure, an outdoor mesocosm study was performed, and the environmental concentrations were predicted by the multimedia paddy-pond model (TOPRICE). The mesocosm experiment showed that tetrachlorantraniliprole mainly stayed in the aqueous phase after entering the water body. Although the chemical dissipated quickly in the aqueous phase (half-life of 0.79-1.5 days), it showed toxic effects on zooplankton communities. Cladocerans, represented by Simocephalus vetulus, were most sensitive to tetrachlorantraniliprole stress. Significant short-term toxicity to cladocerans occurred in all treatment groups, but all recovered within 8 weeks except for the highest concentration group (30.0 µg /L). Based on the ecological recovery results, 7.74 µg tetrachlorantraniliprole/L (nominal concentration, 10.0 µg /L) is suggested to be the no-observed-ecological-adverse-effect concentration (NOEAEC) for the zooplankton community. When this NOEAEC was compared with predicted environmental concentrations (PECs; the PECs in natural ponds simulated by the TOPRICE model for 148 application scheme combinations in major rice-producing areas), a relatively high risk of applying tetrachlorantraniliprole during the rice tillering stage was found. The present study makes a positive contribution to the hypothesis that the current Tier 1 approaches for global acute risk assessment have a sufficient protective effect for assessing the risk of tetrachlorantraniliprole to aquatic organisms. Also, the present results should help us to gain a fuller understanding of the ecological risk of diamide insecticides in aquatic ecosystems and their rational application schemes. Environ Toxicol Chem 2024;43:429-439. © 2023 SETAC.

Cajanol Sensitizes A2780/Taxol Cells to Paclitaxel by Inhibiting the PI3K/Akt/NF-κB Signaling Pathway.

Ovarian cancer is the second most common gynecological malignancy, and one of the most deadly. The bottleneck restricting the treatment of ovarian cancer is its multi-drug resistance to chemotherapy. Cajanol is an isoflavone from pigeon pea (Cajanus cajan) that has been reported to have anti-tumor activity. In this work, we evaluate the effect of cajanol in reversing paclitaxel resistance of the A2780/Taxol ovarian cancer cell line in vitro and in vivo, and we discuss its mechanism of action. We found that 8 µM cajanol significantly restored the sensitivity of A2780/Taxol cells to paclitaxel, and in vivo experiments demonstrated that the combination of 0.5 mM/kg paclitaxel and 2 mM/kg cajanol significantly inhibited the growth of A2780/Taxol metastatic tumors in mice. Flow cytometry, fluorescence quantitative PCR, western blotting and immunohistochemical staining methods were used to study the mechanism of reversing paclitaxel resistance with cajanol. First, we determined that cajanol inhibits paclitaxel efflux in A2780/Taxol cells by down-regulating permeability glycoprotein (P-gp) expression, and further found that cajanol can inhibit P-gp transcription and translation through the PI3K/Akt/NF-κB pathway. The results of this work are expected to provide a new candidate compound for the development of paclitaxel sensitizers.

Numerical Simulations of the Soil-Rock Mixture Mechanical Properties Considering the Influence of Rock Block Proportions by PFC2D.

Soil-rock mixtures (S-RMs), as a kind of special engineering geological material, need to be studied because of the special structure and complex movement mechanism of their rock blocks, their physical and mechanical properties, and the factors underlying rock block movement in the process of their deformation and failure. In this paper, a series of discrete-element numerical models are constructed in particle flow code software (PFC2D). First, the random structure numerical models of S-RMs with different rock block proportions are established. Then, the parameters of the soil meso-structure are inversed by the biaxial simulation test, and a series of biaxial compressive tests are performed. The characteristics of stress and strain, deformation and failure, and rock block rotation and energy evolution are systematically investigated. The results show the following. (1) As the rock block proportion (confining pressure 0.5 MPa) increases, the peak strength of increases, the fluctuations of the post-peak become more obvious, and the dilatancy of the sample increases. (2) As the rock block proportion increases, the width of the shear band increases, the distribution of cracks becomes more complex and dispersed, and the range of the shear zone increases. (3) The number of rock blocks with rotation also increases significantly as rock block proportion increases, and the rotation angles are mostly between -5° and 5°. (4) The strain energy of S-RMs with different rock block proportions follows the same change rule as axial strain, showing a trend of first increasing and then decreasing, like the stress-strain curve.

Long non-coding RNA Arid2-IR affects advanced glycation end products-induced human retinal endothelial cell injury by binding to Smad3.

PURPOSE: Long non-coding RNAs (lncRNAs) have been reported to play significant roles in the pathogenesis of diabetic retinopathy (DR). The aim of the present study was to investigate the role of lncRNA Arid2-IR in advanced glycation end product (AGE)-induced human retinal endothelial cells (HRECs) injury. MATERIALS AND METHODS: Cell viability was determined by Cell Counting Kit-8 assay following induction with AGEs. The expression of Arid2-IR and Smad3 was detected by reverse transcription-quantitative PCR or western blotting. A luciferase reporter assay was conducted to determine the interaction between Arid2-IR and Smad3. The levels of inflammation-related and oxidative stress-related factors were evaluated by respective kits. The expression of extracellular matrix (ECM)-related and apoptosis-related proteins was detected by western blotting. Immunofluorescence assay was used to detect the level of vascular endothelial growth factor, and flow cytometry was applied to measure the levels of apoptosis. RESULTS: The results revealed that AGE treatment decreased HREC proliferation and upregulated the expression of Arid2-IR and Smad3. The luciferase assay indicated that Smad3 was able to bind to the promoter region sequence of Arid2-IR. Moreover, Arid2-IR silencing reduced inflammation, oxidative stress and ECM production induced by AGEs in HRECs, and Smad3 inhibition further reduced the levels of the aforementioned factors, while Smad3 overexpression exerted the opposite effect. Furthermore, apoptosis of HRECs induced by AGEs was decreased following Arid2-IR silencing, which was further reduced following treatment with Smad3 inhibitor, but was reversed after transfection with Smad3 pcDNA3.1. CONCLUSION: The findings demonstrated that Arid2-IR affects AGE-induced HREC injury by binding to Smad3.

[Effect of dexmedetomidine on expression of tight junction protein ZO-1 in kidney tissue of rats with acute kidney injury induced by sepsis].

OBJECTIVE: To observe the effect of dexmedetomidine (DEX) on the expression of tight junction protein ZO-1 in kidney tissues of rats with acute kidney injury (AKI) induced by sepsis. METHODS: Sixty healthy male Sprague-Dawley rats were selected and divided into four groups: sham operation group (Sham group), DEX + Sham group, cecal ligation and puncture (CLP) group and DEX + CLP group according to a random number table, with 15 rats in each group. Each group was then divided into 3 subgroups at 6, 12, and 24 hours after the operation, with 5 rats in each subgroup. Modified CLP was used to establish a sepsis model. In Sham group and DEX + Sham group, only laparotomy and abdominal closure were performed. Each group was given pretreatment 1 hour before modeling. DEX + Sham group and DEX + CLP group were pumped into DEX at a rate of 5 µg×kg-1×h-1 through the caudal vein; Sham group and CLP group were pumped with the equal amount of normal saline through the caudal vein. Rats in each group were sacrificed at 6, 12, and 24 hours after operation to obtain kidney tissue. After hematoxylin-eosin (HE) staining, the pathological changes were observed under a light microscope, and the pathological score of renal injury was calculated. The positive expression level of ZO-1 in kidney tissue was detected by immunohistochemistry. RESULTS: The pathological changes of rat kidney tissue could be seen at 6 hours after CLP. With the prolongation of postoperative time, the degree of renal injury showed a tendency to aggravate, with 24 hours being more significant. Semi-quantitative analysis showed that compared with the Sham group, the CLP group had significantly higher renal injury pathology scores at each time point (1.98±0.37 vs. 0.36±0.25 at 6 hours, 2.62±0.34 vs. 0.39±0.18 at 12 hours, 3.52±0.34 vs. 0.42±0.20 at 24 hours,all P < 0.01); the positive expression level of ZO-1 in kidney tissue was significantly reduced [percentage of positive area: (3.17±0.74)% vs. (10.83±0.83)% at 6 hours, (2.56±0.76)% vs. (9.02±0.88)% at 12 hours, (1.75±0.66)% vs. (8.25±0.94)% at 24 hours, all P < 0.01]. Compared with the CLP group, the pathological score of renal injury in the DEX + CLP group was significantly reduced at each time point (0.66±0.27 vs. 1.98±0.37 at 6 hours, 1.34±0.26 vs. 2.62±0.34 at 12 hours, 2.08±0.38 vs. 3.52±0.34 at 24 hours, all P < 0.01); the positive expression level of ZO-1 in kidney tissue was significantly increased [percentage of positive area: (8.58±0.86)% vs. (3.17±0.74)% at 6 hours, (7.44±1.05)% vs. (2.56±0.76)% at 12 hours, (6.60±0.87)% vs. (1.75±0.66)% at 24 hours, all P < 0.01]. There was no significant difference in renal injury pathology score and ZO-1 positive expression between the DEX+Sham group and the Sham group. CONCLUSIONS: DEX may reduce sepsis-induced AKI in rats by up-regulating the expression of tight junction protein ZO-1 in kidney tissue.

Helicobacter pylori infection associated with type 2 diabetic nephropathy in patients with dyspeptic symptoms.

AIMS: The aim of this conventional case-control study was to investigate the prevalence and relationship between Helicobacter pylori infection in type 2 diabetes mellitus (DM) and diabetic nephropathy (DN). METHODS: A total of 241 type 2 DM patients and 69 non-diabetic subjects with dyspeptic symptoms were enrolled in the study. Gastroduodenal lesions were observed by gastrointestinal endoscopy and the presence of H. pylori was identified by rapid urease test and serum IgG antibodies to H. pylori. According to the urinary albumin excretion rate (UAE), patients were classified into diabetes mellitus group (DM group, with UAE <30 mg/24h); diabetic nephropathy group 1 (DN group 1, with UAE 30 mg/24 h to <300 mg/24 h); and diabetic nephropathy group 2 (DN group 2 ≥ 300 mg/24 h). The 69 non-diabetic subjects were used as control group. The serum levels of inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-8 were determined using ELISA. RESULTS: The prevalence of H. pylori infection in DN group 1 and DN group 2 was 45/72 (62.5%) and 34/53 (64.15%), respectively, which was significantly higher than in control [28/65 (43.1%)] and DM groups [42.9% (27/63)]. No significant differences of H. pylori prevalence were detected between DN groups as well as DM and control groups. Interestingly, in both DN groups, higher levels of IL-8, TNF-α and urinary albumin excretion rate were found in H. pylori positive subjects. CONCLUSIONS: Diabetic nephropathy patients are more susceptible to H. pylori infection. Our data support an association between H. pylori infection and diabetic nephropathy.

Aquatic risk assessment of a novel strobilurin fungicide: A microcosm study compared with the species sensitivity distribution approach.

The ecotoxicological effects of pyraoxystrobin, a novel strobilurin fungicide, were studied using outdoor freshwater microcosms and the species sensitivity distribution approach. The microcosms were treated with pyraoxystrobin at concentrations of 0, 1.0, 3.0, 10, 30 and 100µg/L. Species sensitivity distribution (SSD) curves were constructed by means of acute toxicity data using the BurrliOZ model for fourteen representatives of sensitive invertebrates, algae and fish and eleven taxa of invertebrates and algae, respectively. The responses of zooplankton, phytoplankton and physical and chemical endpoints in microcosms were studied. Zooplankton, especially Sinodiaptomus sarsi was the most sensitive to pyraoxystrobin exposure in the microcosms. Short-term toxic effects (<8 weeks) on zooplankton occurred in 1µg/L treatment group. The duration of toxic effects on S. sarsi could not be evaluated within the initial 56 days. Significant long-term toxic effects were observed at 10, 30 and 100µg/L (>281 days) for S. sarsi and the zooplankton community. Based on the results obtained from the organisms in the microcosm system, 1µg/L was recommended as the NOEAEC (no observed ecologically adverse effect concentration). Also, 0.33µg/L was derived as the Regulatory Acceptable Concentration based on the ecological recovery option (ERO-RAC) of pyraoxystrobin. For all fourteen tested species, the median HC5 (hazardous concentration affecting 5% of species) was 0.86µg/L, and the lower limit HC5 (LL-HC5) was 0.39µg/L. For the eleven taxa of invertebrates and algae tested, the median HC5 was 1.1µg/L, and the LL-HC5 was 0.26µg/L. The present study positively contributes to the suggestion of adequately using acute L(E)C50-based HC5/ LL-HC5 for deriving protective concentrations for strobilurin fungicides, and it should be valuable for full comprehension of the potential toxicity of pyraoxystrobin in aquatic ecosystems.

[Magnetic beads adsorption-PCR detection method of four common foodborne pathogens in food].

OBJECTIVE: To evaluate the adsorption capacity of magnetic beads for common foodborne pathogens. METHODS: Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Cronobacter sakazakii were used as targets, the suitable conditions were obtained by optimization the incubation time, bead size, reaction temperature and so on. The adsorption efficiency of the magnetic beads in analog samples was also tested. RESULTS: The optimum conditions were as follows: 2.0 - 3.0 microm diameter magnetic beads 50 microl, incubation for 60 min under 37 degrees C. In analog samples, the adsorption efficiency of the magnetic beads for Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Cronobacter sakazakii in juice, milk, duck meat were 50% - 84%, 46% - 66%, 54% - 74%, respectively. CONCLUSION: Magnetic beads enrichment technique has high adsorption efficiency, simple to operate, which is meet the requirement for PCR detection.

DNA-based authentication method for detection of yak (Bos grunniens) in meat products.

A TaqMan probe real-time PCR method was developed for rapid detection of yak component in raw and cooked meat products. Specific primers and TaqMan probes of yak (Bos grunniens) were designed in the cytochrome b gene. The specificity of the method was evaluated using pure meat of eight yak breeds (Jiulong, Qinghai plateau, Maiwa, Gannan, Bazhou, Sibu, Zhongdian, and Jiali) samples and nine non-Bos grunniens animals (sheep, goat, pig, chicken, cattle, water buffalo, donkey, horse, and rabbit). DNA showed no cross-reaction with non-Bos grunniens animal DNA. This method proved to be sensitive in detecting the presence of low levels of target DNA obtained from 0.001% (w/w) component in a mixed meat sample. The method also successfully identified commercial yak meat products. The results showed that some yak meat might be involved in business fraud by using cattle meat (in this paper, cattle meat means meat of Bos taurus) instead of yak meat. In conclusion, real-time PCR assay used in this study was shown to be a rapid and sensitive method for detection of yak DNA in fresh meat and cooked meat products.

Characterization of Listeria monocytogenes isolates in import food products of China from 8 provinces between 2005 and 2007.

UNLABELLED: A total of 48 Listeria monocytogenes isolates of different import food products from 8 provinces between 2005 and 2008 were characterized. The serotype and virulence were confirmed for each strain and molecular subtyping were analyzed by multilocus sequence typing (MLST). Twenty five strains were assigned to serotype 1/2a, and 11 isolates to serotype 1/2b, serotype 4b were found in 7 isolate, and the remaining 5 strains were grouped into serotypes 1/2c, 4a, and 4e. Molecular subtyping schemes found thirty two sequence types (STs) among these isolates and the majority of L. monocytogenes strains belonged to lineage II (56%), followed by lineage I (38%), lineage III (6%). Two molecular subtype clusters, cluster A included all isolates of lineage II, while cluster B contained the isolates of lineages I and lineages III. Two L. monocytogenes strains were not grouped in either of the two clusters. Fifty three isolates were as virulent as L. monocytogenes reference strain EGD in mouse virulence assay, while the isolates 22213 and 22265 had low pathogenicity. These results provide the first molecular insight into the L. monocytogenes strains isolated from import food products of 8 provinces in China and indicate the potential risk to cause human disease if intake by contaminated foods. MLST could be used as a routine subtyping method of L. monocytogenes isolates. In China, inspection and quarantine strategies of imported foods should be strengthened. PRACTICAL APPLICATION: There is a potential risk of listeriosis in China and routine subtyping of L. monocytogenes isolates is important. It is necessary for food hygiene management to strengthen the supervision of imported foods.

[Real-time PCR assay for rapid detection of Listeria monocytogenes in simulated milk specimens].

OBJECTIVE: To establish a real-time PCR assay for the rapid detection of Listeria monocytogenes in simulated milk specimens. METHODS: Based on part fragments of hlyO gene, a pair of primers and Taq-Man probe were designed for quantitative detection of L. monocytogenes. The specificity of the primers and probe were tested by using different L. monocytogenes strains and other common pathogenic bacteria. RESULTS: L. monocytogenes strains were positive in the detection and other tested strains were negative. The sensitivity of assay was 9 copies per PCR reaction. CONCLUSION: The specificity and sensitivity of Taq Man real-time PCR technology for detecting L. monocytogenes in simulated dairy specimens were high, and the assay could be completed within 1.5 h. This method could be used to detect other food samples contaminated by L. monocytogenes and identify the cause of food-borne Listeriosis outbreaks.

[Taxonomy of Enterobacter sakazakii and the biological characteristics of the new species and genus].

Enterobacter sakazakii, one of the major pathogens affecting the safety of infant formula powder was defined as a species in 1980. However, the new names and new combinations about Enterobacter sakazakii notified in volume 58, part 6, of the International Journal of Systematic and Evolutionary Microbiology (IJSB). The taxonomic relationship of strains described as E. sakazakii, biological characteristics of its new genus and species, the development related to its isolation and identification were reviewed in this paper, in order to facilitate the related personnel to keep in touch with the latest developments on E. sakazakii. It's also conducive to unify and standardize the Chinese name for E. sakazakii.

Detection of allergen walnut component in food by an improved real-time PCR method.

A real-time PCR method aimed at the gene sequence of the walnut vicilin-like seed storage protein was established for the detection of the allergen walnut in food. The primers and probe were designed based on published methods. The method provided positive results for walnut and negative results for other tested agricultural plant materials including pecan. The intrinsic detection limit of the method was 0.00125 ng of walnut DNA, and the practical detection limit was 0.001% (wt/wt) walnut content in wheat; both of these values are lower than that of previously published methods. Therefore, this real-time PCR method is sufficiently specific and sensitive for the detection of walnut component in food.