Identification and characterization of an L-type lectin from obscure puffer Takifugu obscurus in response to bacterial infection

L-type lectins (LTLs) contain a carbohydrate recognition domain homologous to leguminous lectins, and have functions in selective protein trafficking, sorting and targeting in the secretory pathway of animals. In this study, a novel LTL, designated as ToERGIC-53, was cloned and identified from obscure puffer Takifugu obscurus. The open reading frame of ToERGIC-53 contained 1554 nucleotides encoding 517 amino acid residues. The deduced ToERGIC-53 protein consisted of a signal peptide, a leguminous lectin domain (LTLD), a coiled-coil region, and a transmembrane region. Quantitative real-time PCR showed that ToERGIC-53 was expressed in all examined tissues, with the highest expression level in the liver. The expression of ToERGIC-53 was significantly upregulated after infection with Vibrio harveyi and Staphylococcus aureus. Recombinant ToERGIC-53-LTLD (rToERGIC-53-LTLD) protein could not only agglutinate and bind to one Gram-positive bacterium (S. aureus) and three Gram-negative bacteria (V. harveyi, V. parahaemolyticus and Aeromonas hydrophila), but also bind to glycoconjugates on the surface of bacteria such as lipopolysaccharide, peptidoglycan, mannose and galactose. In addition, rToERGIC-53-LTLD inhibited the growth of bacteria in vitro. All these results suggested that ToERGIC-53 might be a pattern recognition receptor involved in antibacterial immune response of T. obscurus.

Three novel L-type lectins from obscure puffer Takifugu obscurus promote antimicrobial immune response

L-type lectins (LTLs) have leguminous lectin domains that bind to high-mannose-type oligosaccharides. LTLs are involved in glycoprotein secretory pathways and associated with many immune responses. In the present research, three LTL homologs from obscure puffer Takifugu obscurus, designated as ToVIP36-1, ToVIP36-2, and ToVIP36-3, were first cloned and identified. The open reading frames of ToVIP36-1, ToVIP36-2, and ToVIP36-3 were 1068, 1002, and 1086 bp in length, respectively, and encode polypeptides with 355, 333, and 361 amino acids, respectively. Key conserved residues and functional domains, including lectin_leg-like domain (LTLD), transmembrane region, and C-terminal trafficking signal KRFY, were identified in all ToVIP36s. Quantitative real-time PCR analysis showed that the three ToVIP36s were widely expressed in six examined tissues and had relatively high expression levels in the liver and intestine. The expression levels of ToVIP36s were remarkably altered in the liver and kidney after induction by Vibrio harveyi and Staphylococcus aureus. Subsequently, the recombinant LTLDs of ToVIP36s (rToVIP36-LTLDs) were prepared by prokaryotic expression. Three rToVIP36-LTLD proteins agglutinated with S. aureus, V. harveyi, Vibrio parahaemolyticus, and Aeromonas hydrophila in a calcium-dependent manner. In the absence of calcium, rToVIP36-LTLD proteins bound to the bacteria by binding to lipopolysaccharides, peptidoglycans, d-mannose, and d-galactose and inhibited the growth of S. aureus and V. harveyi. Our results indicated that ToVIP36s function as pattern-recognition receptors in T. obscurus immunity, providing insights into the role of LTLs in the antibacterial immunity of fishes.

The mechanism and effects of remdesivir-induced developmental toxicity in zebrafish: Blood flow dysfunction and behavioral alterations

The antiviral drug remdesivir has been used to treat the growing number of coronavirus disease 2019 (COVID-19) patients. However, the drug is mainly excreted through urine and feces and introduced into the environment to affect non-target organisms, including fish, which has raised concerns about potential ecotoxicological effects on aquatic organisms. Moreover, studies on the ecological impacts of remdesivir on aquatic environments have not been reported. Here, we aimed to explore the toxicological impacts of microinjection of remdesivir on zebrafish early embryonic development and larvae and the associated mechanism. We found that 100 μM remdesivir delayed epiboly and impaired convergent movement of embryos during gastrulation, and dose-dependent increases in mortality and malformation were observed in remdesivir-treated embryos. Moreover, 10-100 μM remdesivir decreased blood flow and swimming velocity and altered the behavior of larvae. In terms of molecular mechanisms, eighty differentially expressed genes (DEGs) were identified by transcriptome analysis in the remdesivir-treated group. Some of these DEGs, such as manf, kif3a, hnf1ba, rgn, prkcz, egr1, fosab, nr4a1, and ptgs2b, were mainly involved in early embryonic development, neuronal developmental disorders, vascular disease and the blood flow pathway. These data reveal that remdesivir can impair early embryonic development, blood flow and behavior of zebrafish embryos/larvae, probably due to alterations at the transcriptome level. This study suggests that it is important to avoid the discharge of remdesivir to aquatic ecosystems and provides a theoretical foundation to hinder remdesivir-induced ecotoxicity to aquatic environments.

Genetic variability of Myzus persicae nicotianae densovirus based on partial NS and VP gene sequences

We previously described a novel densovirus [Myzus persicae nicotianae densovirus (MpnDV)] infecting M. persicae nicotianae (Hemiptera: Aphididae) with 34% prevalence. This single-stranded DNA virus has a 5480-nucleotide ambisense genome and belongs to the Densovirinae subfamily within the family Parvoviridae. In the present study, we estimated the genetic diversity of MpnDV using partial nonstructural protein (NS) and capsid protein (VP) gene sequences from 10 locations in China. First, we identified MpnDV-positive samples by amplifying a 445-bp fragment with primers MpDVF/MpDVR. Subsequently, we amplified and sequenced COI genes with primers MpCOIF/ MpCOIR, and partial NS and VP sequences with primers MpnDVF1/MpnDVR1. The respective 655-, 1461-, and 423-bp COI, NS, and VP fragments were used to analyze the genetic diversity of MpnDV using MEGA 6.0 and DnaSP 5.0. The high level of identity shared by all COI sequences (>99%) suggested that the aphids sampled were of the same species, and indicated population homogeneity across the 10 locations investigated. The nucleotide diversity of MpnDV sequences (0.0020 ± 0.0025) was significantly higher than that of the COI genes (0.0002 ± 0.0005). The pairwise fixation index for MpnDV was 0.832, and the total gene flow was 0.05. Phylogenetic analysis revealed that the MpnDV haplotypes clustered according to geographical location, except for those from the Liaoning and Shanxi provinces. In conclusion, MpnDV demonstrated a low level of gene flow and high genetic diversity, suggesting that it is vertically transmitted, and implying that endosymbiotic viruses could be used as markers in studies of insect population genetics.

Modulation of BCRP mediated atypical multidrug resistance phenotype by RNA interference

Multidrug resistance (MDR) in human cancers is one of the major causes of failure of chemotherapy. The emergence of breast cancer resistance protein (BCRP), a member of the ABC transporter family, has necessitated the development of antagonists. To overcome the BCRP-mediated atypical multidrug drug resistance, two small interfering RNA constructs (RNAi) targeting two different regions of BCRP mRNA were designed to inhibit the atypical MDR expression by transfecting them into MCF-7/MX100 cell lines. The multidrug resistance index to mitoxantrone and the intensity of mitoxantrone fluorescence of MCF-7/MX100 decreased after transfected by pSUPER-BCRP-A and pSUPER-BCRP-B respectively; the BCRP mRNA level and the BCRP protein level of MCF-7/MX100 decreased after treated with pSUPER-BCRPs. The two constructed RNAi plasmids could reverse the atypical mutidrug resistance mediated by BCRP, but neither can reversed it completely, this may be due to low transfection efficiency and transient transfection.

[Determination of the pKa value of icariin and its content in the Chinese herb medicine epimedium grandiflorum morr. by capillary electrophoresis]

Knowledge of dissociation constants is important for prediction and understanding the migration behavior of analytes in capillary electrophoresis. Icariin is the active component of the Chinese herb medicine Epimedium grandiflorum Morr.. In order to determine the dissociation constant of icariin and to show many important pharmacology activities, a CZE method has been used to determine the ion mobility (mu A-) and the pKa value of icariin based on the non-linear relation between mu eff and [H+] and the linear relation between the reciprocal of effective mobility of the solute (1/mu eff) and the [H+] of the buffer solution. In addition, the change of pKa of icariin with the increase of ethanol concentration in the buffer was also investigated. Under the buffer condition of 24 mmol/L phosphate + 30% ethanol, the content of the active component icariin in Chinese herb Epimedium grandiflorum Morr. was quantitatively determined. The linear correlation equation was Y = 6.96 x 10(-3) + 17.0X, and the linear range is 0.032 g/L-0.354 g/L.

[Determination of the active components in Chinese herb Aloe vera L. var. chinensis (Haw.) Berger by capillary zone electrophoresis]

It has been proved that the Chinese herb Aloe vera L. var. chinensis (Haw.) Berger as well as its active components showed many important pharmacology activities. In order to find an easy and low-cost method to control the quality of the herb, a CZE method for the determination of the active components aloin and aloe-emodin in Aloe vera L. var. chinensis (Haw.) Berger was developed in this work. Under the buffer conditions of 24 mmol/L phosphate (pH 10.52), applied voltage of 15 kV and detector wavelength of 254 nm, baseline separation of the active compounds in Aloe vera L. var. chinensis (Haw.) Berger was achieved and the active components were quantitatively analyzed. The linear calibration equations of the two components are: Y= -0.140 + 57.2X (r = 0.997) for aloin and Y = -0.393 + 1.08 x 10(2) X (r = 0.999) for aloe-emodin respectively. In addition, the effects of buffer pH value and organic modifier on the migration behavior of the solutes were also investigated.

[Comparative study of the effect of wei-yan-ning and furazolidone in the treatment of gastritis and gastric ulcer caused by pyloric Campylobacter]

Wei-Yan-Ning and Furazolidone were used separately in the treatment of 62 cases of gastritis and gastric ulcer caused by pyloric campylobacteria. The examinations one month later proved, through the gastrofiberscopy and pathological test as well as the urease test, that, among the 40 cases of Wei-Yan-Ning group, there were 25 cures (62.5%), prominent effect for 9 cases (22.5%), improvement for 3 cases (7.5%). The total effective rate was 92.5%. Among the 22 cases of the Furazolidone group, there were 7 cures (31.8%), prominent effect for 5 cases (22.7%), improvement for 4 cases (18.2%). The total effective rate was 72.7%. As for the improvement of symptom, the average time for the Wei-Yan-Ning group was 12.5 +/- 8.12 days; and the Furazolidone group was 21.63 +/- 7.87 days. Therefore, the effect of Wei-Yan-Ning group was superior to that of the Furazolidone group (P less than 0.05).