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1.
Biomacromolecules ; 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34212715

RESUMO

As an important component of biomaterials, collagen provides three-dimensional scaffolds and biological cues for cell adhesion and proliferation in tissue engineering. Recombinant collagen-like proteins, which were initially discovered in Streptococcus pyogenes and produced in heterologous hosts, have been chemically and genetically engineered for biomaterial applications. However, existing collagen-like proteins do not form gels, limiting their utility as biomaterials. Here, we present a series of rationally designed collagen-like proteins composed of a trimerization domain, triple-helical domains with various lengths, and a pair of heterotrimeric coiled-coil sequences attached to the N- and C-termini as adhesive ends. These designed proteins fold into triple helices and form self-supporting gels. As the triple-helical domains are lengthened, the gels become less stiff, pore sizes increase, and structural anisotropy decreases. Moreover, cell-culture assay confirms that the designed proteins are noncytotoxic. This study provides a design strategy for collagen-based biomaterials. The sequence variations reveal a relationship between the protein primary structure and material properties, where variations in the cross-linking density and association energies define the gelation of the protein network.

2.
Adv Mater ; : e2102525, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34223676

RESUMO

In situ electrical control of the Dzyaloshinskii-Moriya interaction (DMI) is one of the central but challenging goals toward skyrmion-based device applications. An atomic design of defective interfaces in spin-orbit-coupled transition-metal oxides can be an appealing strategy to achieve this goal. In this work, by utilizing the distinct formation energies and diffusion barriers of oxygen vacancies at SrRuO3 /SrTiO3 (001), a sharp interface is constructed between oxygen-deficient and stoichiometric SrRuO3 . This interfacial inversion-symmetry breaking leads to a sizable DMI, which can induce skyrmionic magnetic bubbles and the topological Hall effect in a more than 10 unit-cell-thick SrRuO3 . This topological spin texture can be reversibly manipulated through the migration of oxygen vacancies under electric gating. In particular, the topological Hall signal can be deterministically switched ON and OFF. This result implies that the defect-engineered topological spin textures may offer an alternate perspective for future skyrmion-based memristor and synaptic devices.

3.
Artigo em Inglês | MEDLINE | ID: mdl-34312760

RESUMO

Environment-friendly sound measures with high algal growth inhibition efficiency are required to control and eliminate CyanoHABs. This study examined the effects of protopine on growth, gene expression, and antioxidant system of the M. aeruginosa TY001 and explored possible damage mechanism. The results revealed that higher concentrations of protopine seriously inhibited the growth of M. aeruginosa. Quantitative real-time PCR analysis showed downregulated expression of stress response genes (prx and fabZ), and DNA repair gene (recA) on days 3 and 5. The activities of antioxidant enzymes were also decreased markedly, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Additionally, protopine stress can significantly increase the malondialdehyde (MDA) level in cells. In conclusion, oxidative damage and DNA damage are the main mechanisms of protopine inhibition on M. aeruginosa TY001. Our studies provide evidence that alkaloid compounds such as protopine may have a potential use value as components of aquatic management strategies.

4.
Front Endocrinol (Lausanne) ; 12: 598005, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34248833

RESUMO

Diabetes mellitus (DM) is a highly prevalent chronic disease that is accompanied with serious complications, especially cardiac and vascular complications. Thus, there is an urgent need to identify new strategies to treat diabetic cardiac and vascular complications. Nuclear factor erythroid 2-related factor 2 (NRF2) has been verified as a crucial target for the prevention and treatment of diabetic complications. The function of NRF2 in the treatment of diabetic complications has been widely reported, but the role of NRF2-related epigenetic modifications remains unclear. The purpose of this review is to summarize the recent advances in targeting NRF2-related epigenetic modifications in the treatment of cardiac and vascular complications associated with DM. We also discuss agonists that could potentially regulate NRF2-associated epigenetic mechanisms. This review provides a better understanding of strategies to target NRF2 to protect against DM-related cardiac and vascular complications.

5.
Leg Med (Tokyo) ; 53: 101938, 2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34256322

RESUMO

Malignant hyperthermia (MH) is characterized by a rapid rise in body temperature after using inhalational anesthetics and depolarizing muscle relaxants. A 19-year-old female had a rapidly developing fever up to 43.0 °C, after rhinoplasty surgery. Inhalational anesthetics and depolarizing muscle relaxants were used in general anesthesia. It was suspected that the patient died of MH. The medico-legal autopsy findings showed classical MH histopathological changes in the skeletal muscles, cardiac muscles, as well as lungs. Additionally, postmortem blood biochemical results indicated rhabdomyolysis. A combination of clinical records and autopsy revealed that MH might have caused the death. A diagnostic genetic testing was performed to confirm the existence of MH, and an MH diagnostic variant RYR1 c.7048G >A (p. A2350T) was detected. Eventually, the cause of death was determined as MH based on clinical records, autopsy, and genetic analysis. This case highlights that diagnostic genetic analysis plays a vital role in postmortem diagnosis of MH in routine medico-legal contexts.

6.
Anal Chem ; 93(28): 9860-9868, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34247486

RESUMO

Extracellular vesicles (EVs) have recently emerged as a promising tumor biomarker, and EV phenotyping offers many benefits for cancer diagnosis. However, the practicality of EV assays remains a challenge due to macromolecule disturbances, biomarker heterogeneities, and EV abundance limitations. Here, we demonstrate a membrane-based biosensor for precise and sensitive EV identification. The sensor synergistically integrates EV capture and detection by virtue of EV membrane features (membrane protein and lipid bilayer), comprising antibody-conjugated magnetic beads (AbMBs) and duplex-specific nuclease (DSN)-mediated amplification cycles. Bivalent cholesterol (biChol)-modified RNA-DNA duplexes are designed to insert into the EV membrane, transforming EV signals into RNA signals and initiating the signal amplification. The membrane-based signal production pattern eliminates protein interference. By employing four antibodies specific to PCa-related membrane proteins, the AbMB-biChol platform enables the successful differentiation and monitoring of PCa-related EVs and distinguishes PCa patients from healthy donors with improved efficacy, exhibiting superior efficiency over the analyses based on clinically used biomarker CA19-9 and PCa-related proteins. As such, the developed system has great potential for clinical PCa diagnosis.

7.
Int J Mol Sci ; 22(14)2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34298865

RESUMO

Poplar is one of the most important tree species in the north temperate zone, but poplar plantations are quite water intensive. We report here that CaMV 35S promoter-driven overexpression of the PdERECTA gene, which is a member of the LRR-RLKs family from Populus nigra × (Populus deltoides × Populus nigra), improves water use efficiency and enhances drought tolerance in triploid white poplar. PdERECTA localizes to the plasma membrane. Overexpression plants showed lower stomatal density and larger stomatal size. The abaxial stomatal density was 24-34% lower and the stomatal size was 12-14% larger in overexpression lines. Reduced stomatal density led to a sharp restriction of transpiration, which was about 18-35% lower than the control line, and instantaneous water use efficiency was around 14-63% higher in overexpression lines under different conditions. These phenotypic changes led to increased drought tolerance. PdERECTA overexpression plants not only survived longer after stopping watering but also performed better when supplied with limited water, as they had better physical and photosynthesis conditions, faster growth rate, and higher biomass accumulation. Taken together, our data suggest that PdERECTA can alter the development pattern of stomata to reduce stomatal density, which then restricts water consumption, conferring enhanced drought tolerance to poplar. This makes PdERECTA trees promising candidates for establishing more water use efficient plantations.

8.
Molecules ; 26(14)2021 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-34299529

RESUMO

Aroma deterioration is one of the biggest problems in processing tea beverages. The aroma of tea infusion deteriorates fast during heat sterilization and the presence of ferrous ion (Fe2+) aggravates it. The underlying mechanism remains unveiled. In this study, Fe2+ was verified to deteriorate the aroma quality of green tea infusion with heat treatment. Catechins were necessary for Fe2+-mediated aroma deterioration. By enhancing the degradation of catechins, Fe2+ dramatically increased the production of hydrogen peroxide (H2O2). Fe2+ and H2O2 together exacerbated the aroma of green tea infusion with heat treatment. GC-MS analysis revealed that the presence of Fe2+ enhanced the loss of green/grassy volatiles and promoted the formation of new volatiles with diversified aroma characteristics, resulting in a dull scent of green tea infusion. Our results revealed how Fe2+ induced aroma deterioration of green tea infusion with heat treatment and could help guide tea producers in attenuating the aroma deterioration of tea infusion during processing.

9.
Bioengineered ; 12(1): 4432-4441, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34308775

RESUMO

Circular RNAs (circRNAs) play essential roles in the progression of human tumors, including renal cell carcinoma (RCC). The present study aimed to explore the functions and potential mechanisms of human circular RNA hsa_circRNA_101705 (circTXNDC11) in RCC. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to measure circTXNDC11 expression in RCC tissues and cell lines. RNase R and actinomycin D assays were conducted to analyze the characteristic of circTXNDC11. Cell Counting Kit-8 (CCK-8) assay, colony formation assay, and transwell invasion assay were performed to assess cell proliferation and invasion abilities. Western blotting was applied to assess the levels of MEK and ERK proteins in RCC cells. Murine xenograft model assay was conducted to deduce the role of circTXNDC11 in vivo. The current data showed that circTXNDC11 was overexpressed in RCC tissues and cells. The overexpression of circTXNDC11 is linked to advanced TNM stage and lymph node metastasis of renal cancer. Knocking down circTXNDC11 suppressed cell proliferation and invasion in vitro and reduced tumor growth in vivo. Mechanistically, circTXNDC11 promoted RCC growth and invasion by activating the MAPK/ERK pathway. Thus, the current findings identified circTXNDC11 as a novel regulator of RCC tumorigenesis through the regulation of the MAPK/ERK pathway, offering a potential therapeutic target for RCC treatment.

10.
Hypertension ; : HYPERTENSIONAHA12015423, 2021 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-34275335

RESUMO

GPR35 (G-protein-coupled receptor 35) is a poorly characterized receptor that has garnered increased interest as a therapeutic target through its implications in a range of inflammatory and cardiovascular diseases, but its biological functions stay largely unknown. The current study evaluated the effect of GPR35 on endothelial cell (EC) functions and hemodynamic homeostasis. In primary human aortic ECs, the expression of GPR35 was manipulated by transfections of adenovirus carrying either GPR35 cDNA or shRNA against GPR35, using adenovirus carrying ß-gal as control. Mouse aortic ECs were isolated and cultured from GPR35 knockout and wild-type control mice. Our results indicated that genetic inhibition of GPR35 in human and mouse ECs significantly promoted cell proliferation, migration, and tube formation in vitro. The GCH1 (guanosine triphosphate cyclohydrolase I)-mediated biosynthesis of tetrahydrobiopterin was enhanced, reducing intracellular superoxide. Knocking down GCH1 or eNOS (endothelial nitric oxide synthase) significantly blunted the robust angiogenesis induced by GPR35 suppression. Male GPR35 knockout mice demonstrated reduced basal arterial blood pressure and an attenuated onset of hypertension in deoxycorticosterone acetate-salt induced hypertensive model compared with male GPR35 wild-type control mice in vivo, with concomitant improved endothelium-dependent vasodilation and decreased superoxide in isolated aortas. The difference in arterial blood pressure was absent between female GPR35 wild-type control and female GPR35 knockout mice. Our study provides novel insights into the roles of GPR35 in endothelial function and vascular tone modulation that critically contribute to the pathophysiology of blood pressure elevation. Antagonizing GPR35 activity might represent a potentially effective therapeutic approach to restore EC function and hemodynamic homeostasis.

11.
Molecules ; 26(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34279375

RESUMO

Infection is the major reason that people die from burns; however, traditional medical dressings such as gauze cannot restrain bacterial growth and enhance the healing process. Herein, an organic- and inorganic-base hydrogel with antibacterial activities was designed and prepared to treat burn wounds. Oxidized dextran (ODex) and adipic dihydrazide grafted hyaluronic acid (HA-ADH) were prepared, mixed with quaternized chitosan (HACC) and silver nanoparticles to fabricate Ag@ODex/HA-ADH/HACC hydrogel. The hydrogel, composed of nature biomaterials, has a good cytocompatibility and biodegradability. Moreover, the hydrogel has an excellent antibacterial ability and presents fast healing for burn wounds compared with commercial Ag dressings. The Ag@ODex/HA-ADH/HACC hydrogel will be a promising wound dressing to repair burn wounds and will significantly decrease the possibility of bacterial infection.

12.
Oncogene ; 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34290402

RESUMO

The ARID1A gene, which encodes a subunit of the SWI/SNF chromatin remodeling complex, has been found to be frequently mutated in many human cancer types. However, the function and mechanism of ARID1A in cancer metastasis are still unclear. Here, we show that knockdown of ARID1A increases the ability of breast cancer cells to proliferate, migrate, invade, and metastasize in vivo. The ARID1A-related SWI/SNF complex binds to the second exon of CDH1 and negatively modulates the expression of E-cadherin/CDH1 by recruiting the transcriptional repressor ZEB2 to the CDH1 promoter and excluding the presence of RNA polymerase II. The silencing of CDH1 attenuated the migration, invasion, and metastasis of breast cancer cells in which ARID1A was silenced. ARID1A depletion increased the intracellular enzymatic processing of E-cadherin and the production of C-terminal fragment 2 (CTF2) of E-cadherin, which stabilized ß-catenin by competing for binding to the phosphorylation and degradation complex of ß-catenin. The matrix metalloproteinase inhibitor GM6001 inhibited the production of CTF2. In zebrafish and nude mice, ARID1A silencing or CTF2 overexpression activated ß-catenin signaling and promoted migration/invasion and metastasis of cancer cells in vivo. The inhibitors GM6001, BB94, and ICG-001 suppressed the migration and invasion of cancer cells with ARID1A-deficiency. Our findings provide novel insights into the mechanism of ARID1A metastasis and offer a scientific basis for targeted therapy of ARID1A-deficient cancer cells.

13.
Nature ; 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34290409

RESUMO

The mTOR complex 1 (mTORC1) controls cell growth in response to amino acid levels1. Here we report SAR1B as a leucine sensor that regulates mTORC1 signalling in response to intracellular levels of leucine. Under conditions of leucine deficiency, SAR1B inhibits mTORC1 by physically targeting its activator GATOR2. In conditions of leucine sufficiency, SAR1B binds to leucine, undergoes a conformational change and dissociates from GATOR2, which results in mTORC1 activation. SAR1B-GATOR2-mTORC1 signalling is conserved in nematodes and has a role in the regulation of lifespan. Bioinformatic analysis reveals that SAR1B deficiency correlates with the development of lung cancer. The silencing of SAR1B and its paralogue SAR1A promotes mTORC1-dependent growth of lung tumours in mice. Our results reveal that SAR1B is a conserved leucine sensor that has a potential role in the development of lung cancer.

14.
Endokrynol Pol ; 2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34292572

RESUMO

OBJECTIVES: The clinical data of 23 cases of congenital hyperinsulinemia (CHI) treated by pancreatectomy were retrospectively analyzed, and the therapeutic effect and prognosis of pancreatectomy in the treatment of CHI were discussed. METHODS: A total of 23 Chinese children with CHI who had undergone pancreatectomy between February 2002 and March 2020 were selected as the study objects. The clinical data, the results of the 18Fluoro-L-3-4 dihydroxyphenylalanine positron emission tomography/computerized tomography (18F-DOPA PET/CT) scanning, and the diagnosis, treatment, and follow-up were analyzed retrospectively. RESULTS: Among the 23 cases, 14 patients were diagnosed with focal-type CHI via a 18F-DOPA PET/CT scan prior to the operation, with the lesions removed via partial pancreatectomy. After the operation, ten patients (71%) had normal blood glucose levels, while frequent feeding was required in four patients (29%) to control the hypoglycemia. Three cases were diagnosed as diffuse-type CHI via preoperative scanning, two of which were treated by subtotal pancreatectomy, with one returning to normal blood glucose levels, while a subcutaneous injection of octreotide was required in the other to prevent hypoglycemia. The other case was treated by near-total pancreatectomy, and the blood glucose level was normal following the operation. The remaining six cases were not diagnosed via the pancreatic scanning prior to the operation due to the limitation of certain conditions. Here, pancreatectomy was performed directly due to severe hypoglycemia. CONCLUSIONS: 18F-DOPA PET/CT scanning was a reliable method for determining the histological type and localizing the lesion before the operation. Partial pancreatectomy for focal-type CHI had a high cure rate. In the children with diffuse-type CHI, the surgical methods were more complex and the therapeutic effect and the prognosis were also different.

15.
Artigo em Inglês | MEDLINE | ID: mdl-34245411

RESUMO

Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application in treating COVID-19. Most studies on GC removal mainly focused on aquatic environment, while GC behaviors in soil were less mentioned. In this study, degradation of three selected GCs in soil has been investigated using citric acid (CA)-modified Fenton-like processes (H2O2/Fe(III)/CA and CaO2/Fe(III)/CA treatments). The results showed that GCs in soil can be removed by modified Fenton-like processes (removal efficiency gt; 70% for 24 h). CaO2/Fe(III)/CA was more efficient than H2O2/Fe(III)/CA at low oxidant dosage (< 0.28-0.69 mmol/g) for long treatment time (> 4 h). Besides the chemical assessment with GC removal, effects of Fenton-like processes were also evaluated by biological assessments with bacteria and plants. CaO2/Fe(III)/CA was less harmful to the richness and diversity of microorganisms in soil compared to H2O2/Fe(III)/CA. Weaker phytotoxic effects were observed on GC-contaminated soil treated by CaO2/Fe(III)/CA than H2O2/Fe(III)/CA. This study, therefore, recommends CaO2-based treatments to remediate GC-contaminated soils.

16.
Autoimmunity ; : 1-7, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34282692

RESUMO

Chondrocyte apoptosis contributes to osteoarthritis, while miR-146a is a critical player in chondrocyte apoptosis. Our bioinformatics analysis showed that miR-146a may bind with long non-coding RNA (lncRNA) CALML3 antisense RNA 1 (CALML3-AS1). Our study was therefore carried out to investigate the interactions between lncRNA CALML3-AS1 and miR-146a in osteoarthritis. This study included 66 osteoarthritis patients who were admitted at Shanxi People's Hospital from July 2016 to June 2019. Transfections were performed to analyse gene interactions. RT-qPCR and Western blot were performed to determine the expression levels of gene and protein, respectively. Cell apoptosis of chondrocytes induced by lipopolysaccharide (LPS) was analysed by cell apoptosis assay. We found that CALML3-AS1 was downregulated, while miR-146a was upregulated in osteoarthritis. However, no significant correlation was found between them. In addition, overexpression of CALML3-AS1 or miR-146a did not affect the expression of each other. However, overexpression of CALML3-AS1 resulted in the upregulation of Smad family member 4 (Smad4), a downstream target of miR-146a. We also found that the expression of miR-146a and Smad4 were negatively correlated, while the correlation between CALML3-AS1 and smad4 was not significant. In cell apoptosis assay, overexpression of CALML3-AS1 and Smad4 resulted in decreased proliferation of chondrocytes. MiR-146a played an opposite role and reduced the effects of overexpression of CALML3-AS1 and Smad4. Therefore, CALML3-AS1 may regulate chondrocyte apoptosis by acting as a sponge for miR-146a to upregulate Smad4.

17.
Hum Brain Mapp ; 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34288264

RESUMO

The investigation of neural circuits is important for interpreting both healthy brain function and psychiatric disorders. Currently, the architecture of neural circuits is always investigated with fluorescent protein encoding neurotropic virus and ex vivo fluorescent imaging technology. However, it is difficult to obtain a whole-brain neural circuit connection in living animals, due to the limited fluorescent imaging depth. Herein, the noninvasive, whole-brain imaging technique of MRI and the hypotoxicity virus vector AAV (adeno-associated virus) were combined to investigate the whole-brain neural circuits in vivo. AAV2-retro are an artificially-evolved virus vector that permits access to the terminal of neurons and retrograde transport to their cell bodies. By expressing the ferritin protein which could accumulate iron ions and influence the MRI contrast, the neurotropic virus can cause MRI signal changes in the infected regions. For mice injected with the ferritin-encoding virus vector (rAAV2-retro-CAG-Ferritin) in the caudate putamen (CPu), several regions showed significant changes in MRI contrasts, such as PFC (prefrontal cortex), HIP (hippocampus), Ins (insular cortex) and BLA (basolateral amygdala). The expression of ferritin in those regions was also verified with ex vivo fluorescence imaging. In addition, we demonstrated that changes in T2 relaxation time could be used to identify the spread area of the virus in the brain over time. Thus, the neural connections could be longitudinally detected with the in vivo MRI method. This novel technique could be utilized to observe the viral infection process and detect the neural circuits in a living animal.

18.
Sci Rep ; 11(1): 15016, 2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34294801

RESUMO

Low birth weight (< 2500 g; LBW) and macrosomia (> 4000 g) are both adverse birth outcomes with high health risk in short- or long-term period. However, national prevalence estimates of LBW and macrosomia varied partially due to methodology limits in China. The aim of this study is to estimate the prevalence of LBW and macrosomia after taking potential birth weight heaping into consideration in Chinese children under 6 years in 2013. The data were from a nationally representative cross-sectional survey in mainland China in 2013, which consists of 32,276 eligible records. Birth weight data and socio-demographic information was collected using standard questionnaires. Birth weight distributions were examined and LBW and macrosomia estimates were adjusted for potential heaping. The overall prevalence of LBW of Chinese children younger than 6 years was 5.15% in 2013, with 4.57% in boys and 5.68% in girls. LBW rate was higher for children who were minority ethnicity, had less educated mothers, mothers aged over 35 years or under 20 years, or were in lower income household than their counterparts. The overall prevalence of macrosomia of Chinese children younger than 6 years was 7.35% in 2013, with 8.85% in boys and 5.71% in girls. The prevalence of macrosomia increased with increasing maternal age, educational level and household income level. Both LBW and macrosomia varied among different regions and socio-economic groups around China. It is found that estimates based on distribution adjustment might be more accurate and could be used as the foundation for policy-decision and health resource allocation. It would be needed to take potential misclassification of birth weight data arising from heaping into account in future studies.

19.
Chem Commun (Camb) ; 2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34296709

RESUMO

Modular construction of polyfunctional arenes from abundant feedstocks stands as an unremitting pursue in synthetic chemistry, accelerating the discovery of drugs and materials. Herein, using the multiple C-H activation strategy with versatile imidate esters, the expedient delivery of molecular libraries of densely functionalized sulfur-containing arenes was achieved, which enabled the concise construction of biologically active molecules, such as Bipenamol.

20.
Exp Appl Acarol ; 2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34297228

RESUMO

Ticks are hematophagous ectoparasites and cause a major public health threat worldwide. Development of anti-tick vaccines is regarded to be an optimal alternative for tick control. AV422, a unique protein in ticks, is secreted into hosts during blood-feeding, but its roles are not confirmed in Haemaphysalis flava ticks. We retrieved a gene fragment encoding AV422 from a transcriptome dataset of H. flava, and based on it, we reconstructed the full length of AV422 from H. flava (Hf-AV422) by rapid amplification of cDNA ends. Expression profiles of Hf-AV422 in whole ticks and organs of different engorgement levels were determined by qPCR. Then its opening reading frame (ORF) was expressed in Escherichia coli strain BL21 (DE3). The prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) assays were conducted to test anticoagulant activities of the purified recombinant protein (rHf-AV422). The full length of AV422 was 1152 bp. Hf-AV422 showed to be conserved as indicated by multiple sequence alignment. Expression of Hf-AV422 was significantly higher in salivary glands and cuticles than in ovaries. Its expression in whole ticks decreased during engorgement with the highest levels in 1/4 engorged ticks. rHf-AV422 prolonged PT, APTT and TT when incubated with rabbit plasma. Our data demonstrated that Hf-AV422 is a conserved salivary protein with anticoagulant activity. Further studies are needed to test in detail its functional properties to ensure it an adequate antigen candidate for the development of broad-spectrum vaccines against ticks.

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