Search

BACKGROUND: The insect cuticle consists of chitin fibers and a protein matrix, which plays an important role in protecting the body from invasion of various pathogens and prevents water loss. Periodic synthesis and degradation of the cuticle is required for the growth and development of insects. Key genes involved in cuticle formation have long been considered a potential target for pest control. RESULTS: In this study, a member of the RR‐2 subfamily of cuticular protein 8 (DcCP8) was identified from the Diaphorina citri genome database. Immunofluorescence analysis suggested that DcCP8 was mainly located in the Diaphorina citri exocuticle and can be induced to up‐regulate 12 h following 20‐hydroxyecdysone (20E) treatment. Silencing of DcCP8 by RNA interference (RNAi) significantly disrupted the metamorphosis to the adult stage, and improved the permeability of the cuticle. Transmission electron microscopy (TEM) analysis revealed that the synthesis of the exocuticle was impressed after silencing of DcCP8. Furthermore, the recombinant DcCP8 protein exhibited chitin‐binding properties in vitro, down‐regulation of DcCP8 significantly inhibited expression levels of chitin metabolism‐related genes. Additionally, a sprayable RNAi method targeting DcCP8 based on star polycation (SPc) nanoparticles‐wrapped double‐stranded RNA (dsRNA) significantly increased Diaphorina citri mortality. Transcriptome sequencing further confirmed that genes associated with the endocytic pathway and immune response were up‐regulated in Diaphorina citri after SPc treatment. CONCLUSIONS: The current study indicated that DcCP8 is critical for the formation of Diaphorina citri exocuticles, and lays a foundation for Diaphorina citri control based on large‐scale dsRNA nanoparticles. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Validamycin, as a broadly applied antibiotic, has been used to control rice sheath blight disease. Furthermore, validamycin was considered as an insecticide to control agricultural pests. Insight into the mechanism of validamycin's action on insects can provide molecular targets for the control of agricultural pests. In this study, a toxicological test analysis revealed that Spodoptera litura larval growth and development was significantly inhibited and the pupation rate was significantly reduced with the increase of the concentration of validamycin. According to the NMR‐based metabolomic analysis, a total of 15 metabolites involved in glycolysis and tricarboxylic acid cycle (TCA) pathways were identified. Additionally, trehalase activities, glucose and chitin contents were significantly downregulated, but the trehalose content was upregulated after exposure to validamycin. Reverse transcription quantitative PCR analysis revealed that the expression level of genes involved in glycolysis, TCA and chitin synthesis were upregulated after treating with validamycin. Further chitin staining also confirmed that chitin content was downregulated at 12 h after validamycin treatment. Our results indicated that validamycin worked via two different molecular mechanisms, one through inhibiting glycometabolism and the other by inhibiting chitin synthesis in S. litura. The information lays a theoretical foundation for further control of S. litura. [ABSTRACT FROM AUTHOR]

Validamycin has been widely used as a specific competitive inhibitor of trehalase. In our previous research, validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri, resulting in abnormal phenotypes. However, the mechanism of validamycin's action on D. citri remains unclear. Here, using a comparative transcriptome analysis, 464 differentially expressed genes (DEGs) in D. citri were identified after validamycin treatment. A Gene Ontology enrichment analysis revealed that these DEGs were mainly involved in "small molecule process", "structural molecule activity" and "transition metal ion binding". DEGs involved in chitin metabolism, cuticle synthesis and insecticide detoxification were validated by reverse transcription quantitative polymerase chain reaction. The RNA interference of D. citri chitinase‐like protein ENO3 and D. citri cuticle protein 7 genes significantly affected D. citri molting. Moreover, the recombinant chitinase‐like protein ENO3 exhibited a chitin‐binding property, and an antimicrobial activity against Bacillus subtilis. This study provides a first insight into the molecular changes in D. citri after exposure to validamycin and identifies two effective RNA interference targets for D. citri control. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid, Diaphorina citri is the principal vector of huanglongbing, which transmits Candidatus Liberibacter asiaticus. Trehalase is a key enzyme involved in trehalose hydrolysis and plays an important role in insect growth and development. The specific functions of this enzyme in D. citri have not been determined. In this study, three trehalase genes (DcTre1‐1, DcTre1‐2, and DcTre2) were identified based on the D. citri genome database. Bioinformatic analysis showed that DcTre1‐1 and DcTre1‐2 are related to soluble trehalase, whereas DcTre2 is associated with membrane‐bound trehalase. Spatiotemporal expression analysis indicated that DcTre1‐1 and DcTre1‐2 had the highest expression levels in the head and wing, respectively, and DcTre2 had high expression levels in the fat body. Furthermore, DcTre1‐1 and DcTre1‐2 expression levels were induced by 20‐hydroxyecdysone and juvenile hormone Ⅲ, but DcTre2 was unaffected. The expression levels of DcTre1‐1, DcTre1‐2, and DcTre2 were significantly upregulated, which resulted in high mortality after treatment with validamycin. Trehalase activities and glucose contents were downregulated, but the trehalose content increased after treatment with validamycin. In addition, the expression levels of chitin metabolism‐related genes significantly decreased at 24 and 48 h after treatment with validamycin. Furthermore, silencing of DcTre1‐1, DcTre1‐2, and DcTre2 reduced the expression levels of chitin metabolism‐related genes and led to a malformed phenotype of D. citri. These results indicate that D. citri trehalase plays an essential role in regulating chitin metabolism and provides a new target for control of D. citri. [ABSTRACT FROM AUTHOR]

[Objective] The present study was conducted to clone coat protein gene of citrus tristeza virus (CTY) collected from Gannan navel oranges (south of Jiangxi province) and analyze its sequence genetic information, in order to lay the foundation for preventing CTY from spreading by using mild strains cross protection method. [Method] The CP gene of CTY sample was amplified with RT-PCR and sequenced. The recombination and nucleotide sequence composition of CP gene in different CTY samples were detected by using software. The nucleotide genetic distance among collected CTY samples and 10 completed whole genome sequencing CTY isolates were calculated, and followed by sequence homology comparison and phylogenetic tree construction. [Result] Amongst 214 collected citrus leaf samples, 78 samples were infected with CTY, and the disease incidence was 36.4%. Out of 78 CTY samples, only one sample was found to be has genetic recombination. The full-length sequence of CP gene in 78 CTY samples was 672 bp in length, and there were no any base deletion and insertion. The average GC and AT (U) compositions of CP gene were 52.8% and 47.2%, respectively. The CP nucleotide genetic distance amongst 78 CTY samples were 0-0.072, and those between 78 samples and 10 known isolates were 0-0.106, respectively. The nucleotide and its deduced amino acid of CP gene amongst 78 samples shared 89.1%-100.0% and 92.3%-100.0% of homology, and they shared 76.5%-98.9% and 73.6%-99.5% of homologies with 10 known CTY isolates, respectively. The phylogenetic tree analysis results showed that, 78 samples and 10 known CTY isolates could be divided into four groups. The first group (I) contained 49 collected CTY samples and 7 known isolates (6 virulent strains and 1 mild strain). The second group(II) contained 21 collected samples and 2 known isolates Qaha and Mexico-ctv. The third group (III) only contained sample CRJ14 which came from Ruijin region. The fourth group (IV) contained one known isolate HA16-5 and those collected samples from Jiangkou and Ningdu regions of Jiangxi province. [Conclusion] The CP gene of CTY isolates from Gannan navel oranges is highly conserved, and its sequence has variation at a certain extent. There are higher and complex relationship amongst each collected isolate, and most of them are associated with virulent and stem pitting isolates. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the efficacy and safety of adalimumab (ADA) for Crohn's disease. Methods: Electronic databases, including PubMed, Embase, the Cochrane Library, and the Science Citation Index, were searched to retrieve relevant trials. We estimated pooled estimates of the odds ratio (OR) and relevant 95 % confidence interval (CI) using fixed effects model or random effects model as appropriate. Results: Six randomized placebo-controlled studies met the selection criteria. Short-term clinical response/remission and long-term remission were better in the ADA groups than in the control groups ( P < 0.05), both in anti-TNF-naive patients and in subjects who lost their response and/or became intolerant to infliximab (IFX). And ADA was also effective for patients who were previously treated with IFX, and its efficacy in infliximab-exposed patients was probably less than in infliximab-naive patients. In patients with active Crohn's disease (CD), ADA therapy was more effective than placebo for obtaining complete fistula closure. In comparison with placebo, ADA does not increase the risk of serious adverse events. Conclusions: ADA appears to be effective in achieving short-term clinical response/remission, long-term remission, and complete fistula healing in CD, including patients not manageable with IFX, and appears to have a favorable safety profile. A longer duration of follow-up and a larger number of patients are required to better assess the safety profile of ADA in CD. [ABSTRACT FROM AUTHOR]

Chitin deacetylase (CDA) is a chitin degradation enzyme that strictly catalyzes the deacetylation of chitin to form chitosan, which plays an important role in regulating growth and development, as well as the immune response. In this study, a chitin deacetylase 3 gene (CDA3) was identified with a complete open reading frame (ORF) of 1362 bp from the genome database of Diaphorina citri, encoding a protein of 453 amino acids. Spatiotemporal expression analysis suggested that D. citriCDA3 (DcCDA3) had the highest expression level in the integument and third-instar nymph stage. Furthermore, DcCDA3 expression level can be induced by 20-hydroxyecdysone (20E). Injection of Escherichia coli and Staphylococcus aureus induced the upregulation of DcCDA3 in the midgut, while DcCDA3 was downregulated in the fat body. After silencing DcCDA3 by RNA interference, there was no influence on the D. citri phenotype. In addition, bactericidal tests showed that recombinant DcCDA3 inhibited gram-positive bacteria, including S. aureus and Bacillus subtilis (B. subtilis). In conclusion, our results suggest that DcCDA3 might play an important role in the immune response of D. citri. [ABSTRACT FROM AUTHOR]

Aim: To determine the effects of safranal on choroidal neovascularization (CNV) and oxidative stress damage of human choroidal microvascular endothelial cells (HCVECs) and its possible mechanisms., Methods: Forty-five rats were used as a laser-induced CNV model for testing the efficacy and safety of safranal (0.5 mg/kg·d, intraperitoneally) on CNV. CNV leakage on fluorescein angiography (FA) and CNV thickness on histology was compared. HCVECs were used for a H 2 O 2 -induced oxidative stress model to test the effect of safranal in vitro . MTT essay was carried to test the inhibition rate of safranal on cell viability at different concentrations. Tube formation was used to test protective effect of safranal on angiogenesis at different concentrations. mRNA transcriptome sequencing was performed to find the possible signal pathway. The expressions of different molecules and their phosphorylation level were validated by Western blotting., Results: On FA, the average CNV leakage area was 0.73±0.49 and 0.31±0.11 mm 2 ( P =0.012) in the control and safranal-treated group respectively. The average CNV thickness was 127.4±18.75 and 100.6±17.34 µm ( P =0.001) in control and safranal-treated group. Under the condition of oxidative stress, cell proliferation was inhibited by safranal and inhibition rates were 7.4%-35.4% at the different concentrations. For tube formation study, the number of new branches was 364 in control group and 35, 42, and 17 in 20, 40, and 80 µg/mL safranal groups respectively ( P <0.01). From the KEGG pathway bubble graph, the PI3K-AKT signaling pathway showed a high gene ratio. The protein expression was elevated of insulin receptor substrate (IRS) and the phosphorylation level of PI3K, phosphoinositide-dependent protein kinase 1/2 (PDK1/2), AKT and Bcl-2 associated death promoter (BAD) was also elevated under oxidative stress condition but inhibited by safranal., Conclusion: Safranal can inhibit CNV both in vivo and in vitro , and the IRS-PI3K-PDK1/2-AKT-BAD signaling pathway is involved in the pathogenesis of CNV., (International Journal of Ophthalmology Press.)

Aim: To explore the concrete mechanism of a Mongolian compound medicine-Gurigumu-13 (GRGM) for glaucoma treatment., Methods: DBA/2J mice, as glaucoma models, were intragastric administrated with GRGM to study the effect of GRGM on retinal ganglion cells (RGCs). The loss of RGCs was evaluated with the number of RGCs and axons. The expression of the target protein of RGCs or mouse retinas was determined by Western blot. The relative content of malondialdehyde (MDA) was examined by ELISA assay., Results: GRGM distinctly improved retina damage via increasing the number of neurons, RGCs and axons in a concentration dependent manner. Meanwhile, GRGM obviously decreased the high level of MDA and the expression of oxidative stress-related proteins in retinas of DBA/2J mice, but promoted the expression of antioxidant proteins. Additionally, GRGM also significantly inhibited the protein expression of Bip and Chop, which were markers of endoplasmic reticulum stress-induced apoptosis., Conclusion: GRGM have obvious protective effects on RGCs in DBA/2J mice, and increase the number of RGCs and axons via inhibiting oxidative stress and endoplasmic reticulum stress.

An intact L1 define element is 6 kb in length in human genome. The majority of the L1s is truncated and has direction difference, implying that it is interesting to study the effects of different length and directions of L1s on gene. In this work, 7 different segments were obtained from L1-open reading frame 2 (ORF2), each of which was 280 bp in length. Each segment was connected into 8 repeats in head and tail tandem manner and was inserted to downstream of GFP gene in different directions in pEGFP-C1. The inserted ORF2 segments in the sense orientation caused much stronger inhibition on gene transcription and protein expression than antisense sequences did. Among all segments, the first and ninth 280 bp segments of ORF2 in both orientations induced weaker inhibition on gene transcription than other segments in the same orientations and did not induce transcriptional elongation. The distribution of Alu in most regions of genome was inverse ratio with L1. The inserted Alus in both orientations inhibited GFP gene expression, but the inhibition in antisense orientation was stronger than that in sense orientation and the sense Alu was the sequence of inducing transcription elongation. A-rich of ORF2 was probably the molecular basis of its sense orientation with stronger inhibition on gene expression.

Aim: To observe the effect of rhubarb ethanol-extract on hyperlipidemia and liver fatty in rabbits., Methods: Thirty healthy male white rabbits were divided randomly into five groups, six rabbits in each group. The rabbits in control group were fed with common forage. The rabbits in model group were fed with high lipid forage. The rabbits in three different rhubarb groups were fed with high lipid forage and treated with different level rhubarb ethanol-extract (REE). In the process of experiment, periodically measured serology index of the rabbits and observed common physiology index. The rabbits were killed at the end of tenth week, liver fatty degeneration degree and liver coefficient were measured and compared., Results: REE could decrease serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), and increase serum high density lipoprotein cholesterol (HDL-C), and reduce liver fatty de generation and protect liver cell function. And the dose-effect relation was showed among different dose REE groups., Conclusion: REE can significantly reduce blood lipid, prevent and treat hyperlipidemia and liver fatty.

Aim: To observe the synergic action of monkshood polysaccharide (MPS) and adriamycin (ADM) long circulating temperature-sensitive liposome (ALTSL) in targeting therapy for H22 tumor-bearing mice and explore the mechanism., Methods: The anti-tumor activity was evaluated by using the tumor's weight as an index. The life prolongation rate of mice was calculated according to the survival time of the tumor-bearing mice. The killer activity of NK cells and the lymphocyte transformation rate were detected by the LDH release assay and MTT colorimetry, respectively. The apoptosis of tumor cells and the expressions of p53, Fas, Fas-L and caspase-3 were analyzed by flow cytometry. The expressions of IL-2 mRNA and IL-12 mRNA in spleen lymphocytes were determined by RT-PCR. The pathologic changes of tumor, heart, liver and kidney tissues of the tumor-bearing mice were observed under light microscope., Results: Compared with the adriamycin liposome group, the anti-tumor effects were enhanced in (MPS+ALTSL) group with tumor growth inhibitory rate up to 80.4%. The survival time of the tumor-bearing mice in ALTSL and (MPS+ALTSL) groups was significantly prolonged compared with the ADM group (P<0.01). The killer activity of NK cells was higher in ALTSL group than in the NS and ADM groups, and was highest in (MPS+ALTSL) group. The lymphocyte transformation rate of (MPS+ALTSL) group was markedly increased (P<0.01) as compared with the ADM group. The result of RT-PCR indicated that the expressions of IL-2 mRNA and IL-12 mRNA in lymphocytes in the adriamycin long circulating liposome (ALCL) group were significantly higher than those in the ADM group. Expressions of IL-2 mRNA and IL-12 mRNA was much higher in (MPS+ALTSL) group than in ALTSL group. The pathological examination indicated that in (MPS+ALTSL) group, more lymphocytes and monocytes were found in tumor tissue., Conclusion: ALTSL can increase the anti-tumor effect and decrease the side-effects (such as the cytotoxicity) of ADM. MPS combined with ALTSL can enhance killer activity of NK cells and transformation of T cells, supporting their synergic anti-tumor effect.

Aim: To observe the synergistic role between rhIL-2 and adriamycin long circulating temperature-sensitive liposome (ALTSL) in targeting therapy of H22 tumor-bearing mice and explore their anti-tumor mechanism., Methods: The antitumor activity was evaluated by using the tumor's weight as an index. The prolongation rate of mouse life was calculated according to the survival time of the tumor-bearing mice. The killer activity of NK cells and the lymphocyte transformation rate were detected by the LDH and MTT colorimetry, respectively. The apoptosis of tumor cells and the expression of p53, Fas, Fas-L and Caspase-3 were analyzed by flow cytometry (FCM). The expression of IL-2 mRNA and IL-12 mRNA in splenocytes was determined by RT-PCR. The pathologic changes of tumor, heart, liver and kidney tissues of the tumor-bearing mice were observed under light microscope., Results: The tumoristatic rate of rhIL-2+ALTSL (73.5%) was higher than that of adriamycin liposome (ADML) group (67.0%). The survival time of tumor-bearing mice in ALTSL and rhIL-2+ALTSL groups was significantly extended as compared with the NS group (treated with normal saline) and the free ADM group (P <0.01 or P <0.05). The killer activities of NK cells of ALTSL group and rhIL-2+ALTSL group were higher than those of the NS and free ADM groups, and was highest in rhIL-2+ALTSL group. The lymphocyte transformation rate of ALTSL+rhIL-2 group markedly increased ( P <0.01) as compared with the free ADM group. The result of RT-PCR indicated that the expression of IL-2 mRNA and IL-12 mRNA in splenocytes in the adriamycin long circulating liposome (ALCL) group was significantly higher than that in the free ADM group. The enhancement of rhIL-2+ALTSL on expression of IL-2 mRNA and IL-12 mRNA was much stronger than that of ALTSL alone. The pathological examination indicated that in rhIL-2+ALTSL group, the tumor cells were mostly destroyed, and a large amount of lymphocytes and monocytes were found in tumor tissue., Conclusion: ALTSL can increase the anti-tumor effect and decreased the side-effects (such as the cytotoxicity) of ADM. rhIL-2+ALTSL can induce the apoptosis of tumor cells and enhance killer activities of T cells and NK cells. rhIL-2 and ALTSL can synergistically play the antitumor effect.

Aim: To prepare monoclonal antibody(mAb) against human c-erbB2 and identify its specificity., Methods: The epitope of human c-erbB2 antigen was analyzed by using computer software and a immunodominant epitope at the carboxyl-terminal was selected. A peptide consisting of 13 amino acids was synthesized and coupled with keyholelimpet hemocyanin (KLH), and then it was used to immunize BLAB/c mice. The splenocytes of the immunized mice were fused with Sp2/0 cells routinely and the hybridoma cells were selected by HAT selected culture, indirect ELISA, and immunohistochemical staining, and cloned by limiting dilution. The specificity of the mAb was identified by cross-reaction test and blocking test., Results: A hybridoma cell line SC8C1, stably secreting anti-c-erbB2 mAb was obtained. The mAb SC8C1 could react to breast cancer tissue expressing c-erbB2 molecule but did not react to other c-erbB2-negative cells. The mAb will lose the activity after being blocked with synthesized 13 peptide., Conclusion: A anti-c-erbB2 mAb SC8C1 is prepared successfully using synthesized 13 peptide as immunogen.

Background & Objective: Thalidomide may have curative effect on tumor because of its function of anti-angiogenesis. The aim of this research was to observe the effect of thalidomide on tumor homograft growth in mouse H22 model and to investigate the mechanisms involved and its curative possibility to hepatoma., Methods: BALB/c mice were inoculated subcutaneously with H22 cells. The first treatment group was injected intraperitoneal everyday with thalidomide 50 mg/kg from the day of inoculation and the second treatment group was injected from the fourth day of inoculation. The diameters of the tumors were measured everyday. On the twelfth day, the mice were sacrificed and the tumors were weighed. The microvessel densities of the tumors were measured by immunohistochemical staining with anti-CD31 monoclonal antibody; CD31 expression, apoptosis, and proliferation were analyzed by flow cytometry. Expression of vascular endothelial growth factor (VEGF) mRNA was examined by reverse transcription-polymerase chain reaction (RT-PCR)., Results: The tumor weight of the first treatment group (2.27+/-0.33 g) was decreased compared with that of control group (2.70+/-0.61 g) (P >0.05); the ratio of inhibition was 15.93%. The tumor weight of the second treatment group (3.32+/-0.47 g) was decreased compared with that of control group (3.42+/-0.60 g) (P >0.05); the ratio of inhibition was 2.92%. The microvessel count (48.40+/-12.90) and CD31 expression (5.59+/-0.75) of the first treatment group were significantly decreased (P< 0.05) in comparison with those of control groups (81.20+/-26.91,7.04+/-0.50) (P< 0.05). The microvessel count (46.4+/-9.71) and CD31 expression (7.29+/-0.48) of the second treatment group were not statistically significant (P >0.05) compared with those of control groups (74.0+/-32.69, 6.80+/-0.68) (P >0.05). The apoptosis indices of the two treatment groups (17.20+/-7.80,15.33+/-4.10) were significantly increased, compared with control groups (4.37+/-1.98,4.87+/-1.91) (P< 0.05), while there was no significant difference of VEGF mRNA expression between the two treatment groups and control groups (P >0.05). The relative quantities of VEGF mRNA of the two treatment groups were 0.50+/-0.13 and 0.51+/-0.06 (control groups:0.48+/-0.11 and 0.64+/-0.11) (P >0.05), respectively., Conclusion: Thalidomide can significantly induce apoptosis and inhibit angiogenesis in mouse H22 model when it is used at the beginning of carcinogenesis, but it has no obvious anti-angiogenic efficacy on the grown tumor. Thalidomide cannot inhibit VEGF mRNA expression of grafted H22 tumor in mouse.

Aim: To observe the synergistic inhibitory effects of rhIL-2 and adriamycin magnetic albumin microsphere(ADM-MAM) targeting therapy on tumor and to explore their antitumor mechanism., Methods: The antitumor activity was observed using the tumor weight as index. The killer activity of natural killer (NK) cells and the lymphocyte transformation were examined by the LDH release assay and MTT colorimetry, respectively. The apoptosis of tumor cells and the expressions of p53,Fas and FasL were examined by flow cytometry. The expressions of IL-2 and IL-12 were determined by RT-PCR., Results: Compared with the control group, in ADM-MAM targeting therapy group and combination therapy (ADM-MAM and rhIL-2 therapy) group, tumor weight, killer activity of NK cells, and the lymphocyte transformation;were obviously decreased; while the expression of Fas, FasL, IL-2 and IL-12 were markedly increased., Conclusion: ADM-MAM targeting therapy exerts anti-tumor effects with fewer side effects, which can be enhanced when combined with rhIL-2 therapy. Such synergistic anti-tumor effects may be realized by stimulating the proliferation of T cells and growth of NK cell to enhance cellular immunological function.