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1.
Cell Microbiol ; : e13294, 2020 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-33222390

RESUMO

Gametogenesis, the formation of gametes from gametocytes, an essential step for malaria parasite transmission, is targeted by transmission-blocking drugs and vaccines. We identified a conserved protein (PBANKA_0305900) in Plasmodium berghei, which encodes a protein of 22 kDa (thus named Pb22) and is expressed in both asexual stages and gametocytes. Its homologues are present in all Plasmodium species and its closely related, Hepatocystis, but not in other apicomplexans. Pb22 protein was localised in the cytosols of schizonts, as well as male and female gametocytes. During gamete-to-ookinete development, Pb22 became localised on the plasma membranes of gametes and ookinetes. Compared to the wild-type (WT) parasites, P. berghei with pb22 knockout (KO) showed a significant reduction in exflagellation (~89%) of male gametocytes and ookinete number (~97%) during in vitro ookinete culture. Mosquito feeding assays showed that ookinete and oocyst formation of the pb22-KO line in mosquito midguts was almost completely abolished. These defects were rescued in parasites where pb22 was restored. Cross-fertilisation experiments with parasite lines defective in either male or female gametes confirmed that the defects in the pb22-KO line were restricted to the male gametes, whereas female gametes in the pb22-KO line were fertile at the WT level. Detailed analysis of male gametogenesis showed that 30% of the male gametocytes in the pb22-KO line failed to assemble the axonemes, whereas ~48.9% of the male gametocytes formed flagella but failed to egress from the host erythrocyte. To explore its transmission-blocking potential, recombinant Pb22 (rPb22) was expressed and used to immunise mice. in vitro assays showed that the rPb22-antisera significantly inhibited exflagellation by ~64.8% and ookinete formation by ~93.4%. Mosquitoes after feeding on rPb22-immunised mice also showed significant decreases in infection prevalence (83.3-93.3%) and oocyst density (93.5-99.6%). Further studies of the Pb22 orthologues in human malaria parasites are warranted.

2.
Thorac Cancer ; 2020 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-33225621

RESUMO

Malignant pleural mesothelioma (MPM) is a type of cancer originating from the pleura with high aggressiveness and poor prognosis. A timely diagnosis is crucial to improve its prognosis. Laboratory biomarkers have significant advantages of reduced invasiveness, low cost, and are observer-independent, and therefore represent a promising diagnostic tool for MPM. MicroRNA is a family of non-coding RNA that regulates gene expression at the post-transcriptional level. Accumulated studies showed that microRNA, either in tissue, circulating, and body fluid, has potential diagnostic value for various disorders. Here, we reviewed the diagnostic value of microRNA for MPM.

3.
Eur J Med Chem ; 207: 112796, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32942073

RESUMO

Intrinsic Xase (iXase), the last and rate-limiting enzyme complex in the intrinsic coagulation pathway, may be an ideal target for antithrombotic treatment. A depolymerized fraction of fucosylated glycosaminoglycan from sea cucumber Holothuria fuscopunctata, dHG-5 (Mw 5.2 kDa), showed potent and selective inhibition of iXase (IC50, 14 nM). In this work, the series of oligosaccharides contained in dHG-5 were purified and their precise structures were confirmed by 2D NMR and MS spectra. The relationships between anti-iXase, f.IXa-binding, anticoagulant and antithrombotic activities (y) and molecular weight (x) could be approximately expressed as the power function (y = a × xb), and these activity potencies of dHG-5 were approximately equivalent to the weighted average sum of that of its oligosaccharides. Given the prominent pharmacological properties, well-defined chemical composition and explicable relationships between dHG-5 and its oligosaccharides in pharmacological behaviors, dHG-5 is expected to be an ideal novel anticoagulant medicine.

4.
Arab J Gastroenterol ; 21(3): 199-206, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32830093

RESUMO

BACKGROUND AND STUDY AIMS: Gastric cancer (GC) is one of the most common malignant tumours worldwide. Long non-coding RNAs (lncRNAs) and microRNAs regulate the occurrence and development of various cancers and play an important role in GC progression. X-inactive specific transcript (XIST), a carcinogenic lncRNA, is involved in human tumourigenesis and is altered in GC. Janus kinase 2 (JAK2), a transcription factor, is involved in cancer cell metastasis and differentiation. However, the exact mechanism underlying the biological roles of XIST and JAK2 in cancer cells remains unclear. MATERIAL AND METHODS: This study was conducted using GES-1, HGC-27, AGS and HEK-293 T cells. Quantitative polymerase chain reaction and western blotting were performed to detect XIST, microRNA-337 (miR-337) and JAK2 expressions. GC cell invasion was investigated by using the Transwell assay. Fluorescein reporter gene detection was used to determine the relationship between JAK2 and XIST. RESULTS: Compared with that in GES-1 cells, XIST expression was significantly up-regulated in AGS and HGC-27 cells. miR-337 expression in GC cell lines was decreased. The proliferation, invasion and migration of GC cells were simultaneously inhibited by XIST knockdown, and the relationship between XIST and miR-337 was confirmed by bioinformatics analysis. JAK2 is expected to be the target gene of miR-337. MiR-337 can negatively regulate JAK2 expression in vitro. In addition, si-XIST decreased JAK2 expression by up-regulating miR-337 in vitro, thereby inhibiting GC cell proliferation and migration. Therefore, we speculated that XIST regulates JAK2 by competing with miR-337 as a competitive endogenous lncRNA in GC. CONCLUSION: We elucidated the effects of migration and invasion after XIST inhibition, at least in part, by inhibiting miR-337 expression in GC cells to regulate JAK2. These data indicate that a positive feedback loop exists between XIST and JAK2 and suggest that JAK2 and XIST play a vital role in cancer cell migration and invasion.

5.
Artigo em Inglês | MEDLINE | ID: mdl-32670896

RESUMO

Quiescin sulfhydryl oxidase (QSOX), present in a wide variety of eukaryotic species, catalyzes the insertion of disulfide bonds into unfolded, reduced proteins. Here we characterized the QSOX protein from the rodent malaria parasite Plasmodium berghei (PbQSOX), which is conserved in all sequenced malaria parasite species. The PbQSOX protein was not expressed in asexual erythrocytic stages, but was most abundantly expressed in ookinetes. Indirect immunofluorescence assays revealed PbQSOX was not only localized in cytoplasm of gametocytes, gametes and ookinetes, but also expressed on the surface of gametes and ookinetes. Western blot identified extracellular presence of PbQSOX in the culture medium of ookinetes suggestive of secretion. Pbqsox deletion (Δpbqsox) did not affect asexual intraerythrocytic development, but reduced exflagellation of male gametocytes as well as formation and maturation of ookinetes. Pbqsox deletion also led to a significant increase in the reduced thiol groups of ookinete surface proteins, suggesting that it may play a role in maintaining the integrity of disulfide bonds of surface proteins, which might be needed for ookinete development. Mosquitoes that fed on Δpbqsox-infected mice showed a significant reduction in ookinete and oocyst numbers compared to those fed on wild-type parasite-infected mice. Further, both polyclonal mouse antisera and a monoclonal antibody against the recombinant PbQSOX exhibited substantial transmission-blocking activities in in vitro and mosquito feeding assays, suggesting QSOX is a potential target for blocking parasite transmission.

6.
Infect Drug Resist ; 13: 1537-1546, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547123

RESUMO

Purpose: The study investigates the molecular epidemiology of multi-drug resistant (MDR) Bacteroides spp. isolates and the clinical characteristics of the patients. Materials and Methods: Bacteroides spp. clinical strains were identified through MALDI-TOF MS and VITEK-2 anaerobes and corynebacterium (ANC) cards. A broth microdilution method was employed to detect the antimicrobial sensitivities of Bacteroides spp. isolates. PCR was used to detect the resistance genes, including cfxA, cepA, cfiA, ermF, nim, as well as the upstream insertion sequence (IS) element of the cfiA gene. The effects of broad-spectrum efflux pump inhibitors (EPIs) on the minimal inhibitory concentration (MICs) of cefoxitin, moxifloxacin, and imipenem for MDR Bacteroides spp. were investigated. Results: The total resistance rates of 115 Bacteroides spp. isolates to cefoxitin, moxifloxacin, clindamycin, metronidazole, imipenem and meropenem were 4.3%, 16.5%, 80.0%, 5.2%, 13.9% and 13.9%, respectively. The positive rates of carbapenem resistance gene cfiA were 38.9% and 8.6% for B. fragilis and non-B. fragilis isolates, respectively. The isolation rate of MDR isolates reached up to 18.26% (21/115), and the isolation rate among the gastrointestinal cancer patients was significantly higher when compared to the non-gastrointestinal cancer patients (52.38%/26.08%, P = 0.006). Furthermore, MDR isolates were more likely to be isolated from the patients exposed to cephalosporins 3 months before Bacteroides spp. isolation (76.19%/31.52%, P = 0.000). Conclusion: The overall resistance rates of Bacteroides spp. isolates against multiple antimicrobials were at a high level, especially for B. fragilis. The CfiA gene carrying rate among B. fragilis isolates was as high as 38.9%, and its mediated carbapenem resistance was the major resistance mechanism for B. fragilis. The findings of this study imply that the real resistance tendency of Bacteroides spp. may be underestimated and need to be given more attention.

7.
Thorac Cancer ; 11(2): 465-469, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31880403

RESUMO

Paraneoplastic neurological syndromes (PNS) are rare disorders affecting any part of the central, peripheral or autonomic nervous system that occur in association with cancer. Among cancer patients, less than 1% overall develop PNS. Anti-SOX1 antibodies' positive paraneoplastic neurological disorders are rare and are usually associated with small cell lung cancer (SCLC). Here, we report a case of a 61-year-old male patient who presented with an unusual anti-SOX1 positive PNS. The right tibialis anterior showed noticeable low-amplitude motor unit potentials and high amplitude motor potentials in electrodiagnostic study, suggesting the presence of Lambert-Eaton myasthenic syndrome (LEMS). Typical MRI and PET-CT found a hyperintense lesion with contrast enhancement in the thorax in front of 5-6 centrum of vertebrae, and thoracoscopic biopsy revealed pathological findings for SCLC. The patient underwent several lines of chemotherapy and radiotherapy and survived for 15 months after the diagnosis of SCLC.

8.
Mar Drugs ; 17(4)2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30934713

RESUMO

Apostichopus japonicus is one of the most economically important species in sea cucumber aquaculture in China. Fucosylated glycosaminoglycan from A. japonicus (AjFG) has shown multiple pharmacological activities. However, results from studies on the structure of AjFG are still controversial. In this study, the deaminative depolymerization method that is glycosidic bond-selective was used to prepare the depolymerized products from AjFG (dAjFG), and then a series of purified oligosaccharide fragments such as tri-, hexa-, nona-, and dodecasaccharides were obtained from dAjFG by gel permeation chromatography. The 1D/2D NMR and ESI-MS spectrometry analyses showed that these oligosaccharides had the structural formula of l-FucS-α1,3-d-GlcA-ß1,3-{d-GalNAc4S6S-ß1,4-[l-FucS-α1,3-]d-GlcA-ß1,3-}n-d-anTal-diol4S6S (n = 0, 1, 2, 3; FucS represents Fuc2S4S, Fuc3S4S, or Fuc4S). Thus, the unambiguous structure of native AjFG can be rationally deduced: it had the backbone of {-4-d-GlcA-ß1,3-d-GalNAc4S6S-ß1-}n, which is similar to chondroitin sulfate E, and each d-GlcA residue in the backbone was branched with a l-FucS monosaccharide at O-3. Bioactivity assays confirmed that dAjFG and nonasaccharides and dodecasaccharides from AjFG had potent anticoagulant activity by intrinsic FXase inhibition while avoiding side effects such as FXII activation and platelet aggregation.


Assuntos
Anticoagulantes/farmacologia , Glicosaminoglicanos/química , Glicosaminoglicanos/farmacologia , Oligossacarídeos/farmacologia , Stichopus/química , Animais , Anticoagulantes/química , Coagulação Sanguínea/efeitos dos fármacos , Sequência de Carboidratos , Fator XII/metabolismo , Humanos , Estrutura Molecular , Oligossacarídeos/química , Tempo de Tromboplastina Parcial , Agregação Plaquetária/efeitos dos fármacos , Relação Estrutura-Atividade
9.
Mar Drugs ; 17(4)2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30934819

RESUMO

Sulfated polysaccharides from sea cucumbers possess distinct chemical structure and various biological activities. Herein, three types of polysaccharides were isolated and purified from Pattalus mollis, and their structures and bioactivities were analyzed. The fucosylated glycosaminoglycan (PmFG) had a CS-like backbone composed of the repeating units of {-4-d-GlcA-ß-1,3-d-GalNAc4S6S-ß-1-}, and branches of a sulfated α-l-Fuc (including Fuc2S4S, Fuc3S4S and Fuc4S with a molar ratio of 2:2.5:1) linked to O-3 of each d-GlcA. The fucan sulfate (PmFS) had a backbone consisting of a repetitively linked unit {-4-l-Fuc2S-α-1-}, and interestingly, every trisaccharide unit in its backbone was branched with a sulfated α-l-Fuc (Fuc4S or Fuc3S with a molar ratio of 4:1). Apart from the sulfated polysaccharides, two neutral glycans (PmNG-1 & -2) differing in molecular weight were also obtained and their structures were similar to animal glycogen. Anticoagulant assays indicated that PmFG and PmFS possessed strong APTT prolonging and intrinsic factor Xase inhibition activities, and the sulfated α-l-Fuc branches might contribute to the anticoagulant and anti-FXase activities of both PmFG and PmFS.


Assuntos
Anticoagulantes/química , Anticoagulantes/farmacologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Pepinos-do-Mar/química , Animais , Anticoagulantes/isolamento & purificação , Coagulação Sanguínea/efeitos dos fármacos , Sequência de Carboidratos , Físico-Química , Cromatografia Líquida de Alta Pressão , Cisteína Endopeptidases , Humanos , Estrutura Molecular , Proteínas de Neoplasias/antagonistas & inibidores , Ressonância Magnética Nuclear Biomolecular , Polissacarídeos/isolamento & purificação , Relação Estrutura-Atividade , Sulfatos/química , Sulfatos/isolamento & purificação , Sulfatos/farmacologia
10.
Infect Immun ; 86(8)2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29866905

RESUMO

Transmission-blocking vaccines (TBVs) interrupting malaria transmission are an integrated tool for malaria eradication. We characterized a sexual-stage-specific gene (PBANKA_060330) from Plasmodium berghei and studied its potential for use as a TBV. This gene, referred to as pbg37, encodes a protein of 37 kDa with a signal peptide and multiple transmembrane domains and is preferentially expressed in gametocytes. A recombinant Pbg37 (rPbg37) protein targeting the N-terminal 63 amino acids (amino acids 26 to 88) expressed in bacteria elicited strong antibody responses in mice. Western blotting demonstrated Pbg37 expression in gametocytes, zygotes, and, to a lesser extent, ookinetes and its predominant association with the membranes of gametocytes. Indirect immunofluorescence assay showed an abundant surface localization of Pbg37 on gametes and zygotes but reduced amounts on retorts and ookinetes. Knockout of pbg37 (Δpbg37) led to a considerable reduction in gametocytemia, which translated into a ~92.1% decrease in the oocyst number in mosquitoes. Deletion of pbg37 had a more substantial influence on the development and maturation of microgametocytes. As a result, the Δpbg37 lines exhibited a higher female/male gametocyte ratio, fewer mature male gametocytes, and defects in the exflagellation of mature microgametocytes. To test the transmission-blocking potential of Pbg37, an in vitro ookinete assay showed that the major inhibitory effects of anti-Pbg37 antiserum were on the exflagellation and fertilization processes. Direct feeding of mosquitoes on mice immunized with rPbg37 or a control protein showed that rPbg37-immunized and P. berghei-infected mice had a significant reduction (49.1%) in oocyst density compared to the controls. The conservation of this gene in Plasmodium warrants further investigations in human malaria parasites.


Assuntos
Transmissão de Doença Infecciosa/prevenção & controle , Vacinas Antimaláricas/imunologia , Malária/prevenção & controle , Plasmodium berghei/imunologia , Proteínas de Protozoários/imunologia , Animais , Anticorpos Antiprotozoários/sangue , Formação de Anticorpos , Western Blotting , Modelos Animais de Doenças , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Deleção de Genes , Perfilação da Expressão Gênica , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/genética , Masculino , Proteínas de Membrana/análise , Proteínas de Membrana/imunologia , Camundongos Endogâmicos BALB C , Mosquitos Vetores/parasitologia , Carga Parasitária , Parasitemia , Plasmodium berghei/química , Plasmodium berghei/genética , Proteínas de Protozoários/análise , Proteínas de Protozoários/genética , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Virulência
11.
Thorac Cancer ; 9(8): 1074-1077, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29802756

RESUMO

Trapped lung is defined by the lung's inability to expand and fill the thoracic cavity because of a restricting "peel" caused by benign or malignant pleural disease. However, trapped lung secondary to pneumothorax is rarely reported. We present a case of trapped lung caused by a pneumothorax that occurred some 14 years before the patient presented to our hospital with a complaint of incapacitating dyspnea. Computed tomography (CT) scans revealed trapping of the right lung with abnormal thickening of the visceral pleura. In view of the patient's history of pneumothorax, we concluded that his dyspnea was attributable mainly to the trapping of his lung by the earlier pneumothorax. We therefore scheduled thoracoscopic decortication, which was successfully completed. The patient's recovery after the operation was uneventful, and seven weeks after surgery the right lung had re-expanded well.


Assuntos
Pneumopatias Obstrutivas/cirurgia , Pneumotórax/complicações , Cirurgia Torácica Vídeoassistida/métodos , Humanos , Pneumopatias Obstrutivas/diagnóstico por imagem , Pneumopatias Obstrutivas/etiologia , Masculino , Pessoa de Meia-Idade , Toracoscopia , Tomografia Computadorizada por Raios X
12.
Carbohydr Polym ; 186: 217-225, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29455981

RESUMO

The digestibility of fucosylated glycosaminoglycan (FG) and its effects on digestive enzymes were investigated using an in vitro digestion model. Results showed that the molecular weight and the reducing sugar content of FG were not significantly changed, and no free monosaccharides released from FG were detected after the salivary, gastric and intestinal digestion, indicating that both the backbone and the sulfated fucose branches of FG are resistant to be cleaved in the saliva and gastrointestinal tract environments. Furthermore, FG can dose-dependently inhibit digestive enzymes such as α-amylase, pepsin and pancreatic lipase in different degrees under the simulated digestion conditions due to the sulfate and carboxyl groups. These physiological effects of FG may help control the postprandial glucose concentration and have the potential in the prevention or treatment of reflux disease and obesity. The findings may provide information on the digestibility and beneficial physiological effects of FG as a potential natural product to promote human health.


Assuntos
Trato Gastrointestinal/metabolismo , Glicosaminoglicanos/metabolismo , Pepinos-do-Mar/metabolismo , Animais , Gastroenteropatias/metabolismo , Monossacarídeos/metabolismo , Pepsina A/metabolismo , alfa-Amilases/metabolismo
13.
Malar J ; 16(1): 458, 2017 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-29132428

RESUMO

BACKGROUND: A vaccine that targets multiple developmental stages of malaria parasites would be an effective tool for malaria control and elimination. METHODS: A conserved gene in Plasmodium, the Plasmodium berghei gene (PBANKA_020570) encoding a 51 kDa protein (pb51 gene), was identified through search of the PlasmoDB database using a combination of expression and protein localization criteria. A partial domain of the Pb51 protein was expressed in a prokaryotic expression system (rPb51) and used for immunization in mice. The protein expression profile and localization were studied by Western blot and indirect immunofluorescence assay (IFA), respectively. The inhibitory effect of the anti-rPb51 antibodies on parasite proliferation was evaluated in erythrocytes in vivo. The transmission-blocking activity of the immune sera was determined by in vitro ookinete conversion assay and by direct mosquito feeding assay (DFA). RESULTS: The rPb51 elicited specific antibodies in mice. Western blot confirmed Pb51 expression in schizonts, gametocytes and ookinetes. IFA showed localization of Pb51 on the outer membranes of schizonts, gametocytes, zygotes, retorts, ookinetes and sporozoites of P. berghei. Mice immunized with the rPb51 protein significantly reduced parasite proliferation and gametocyte conversion in vivo. Moreover, the rPb51 antisera also significantly reduced the in vitro ookinete conversion when added into the ookinete culture medium. In DFA, mice immunized with the rPb51 reduced the prevalence of mosquito infection by 21.3% and oocyst density by 54.8%. CONCLUSIONS: In P. berghei, P51 was expressed in both asexual erythrocytic and sexual stages and localized on the surface of these stages with the exception of the ring stage. The anti-rPb51 antibodies inhibited both P. berghei proliferation in mice and transmission of the parasite to mosquitoes.


Assuntos
Vacinas Antimaláricas/imunologia , Malária/prevenção & controle , Plasmodium berghei/imunologia , Proteínas de Protozoários/genética , Animais , Western Blotting , Proliferação de Células/efeitos dos fármacos , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Malária/parasitologia , Malária/transmissão , Camundongos , Camundongos Endogâmicos BALB C , Plasmodium berghei/genética , Proteínas de Protozoários/metabolismo , Coelhos
14.
Thorac Cancer ; 8(6): 710-713, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28851076

RESUMO

Invasive mucinous adenocarcinoma (IMA) is an uncommon entity in the lung, with a poor prognosis. Multifocal IMA of the lung is even more unusual, and there is little experience with effective treatments. Herein, we present a case of multifocal IMA diagnosed in a 36 year-old man by video-assisted thoracoscopic surgery. A right middle lobe and a nodule in the right upper lobe were resected, as were mediastinal lymph nodes, leaving behind an autonomous right lower lobe nodule. To explore the feasibility of molecular treatment, next-generation sequencing of genetic mutations was performed after four cycles of chemotherapy (pemetrexed + cisplatin). Ultimately, a KIAA1468-RET fusion gene was detected at a disproportionate level (~67.3%), indicating that targeted therapy may be efficacious in treating this disease.


Assuntos
Adenocarcinoma Mucinoso/terapia , Neoplasias Pulmonares/terapia , Proteínas de Neoplasias/genética , Proteínas Proto-Oncogênicas c-ret/genética , Adenocarcinoma Mucinoso/diagnóstico , Adenocarcinoma Mucinoso/genética , Adulto , Cisplatino/uso terapêutico , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Masculino , Proteínas de Fusão Oncogênica/genética , Pemetrexede/uso terapêutico , Análise de Sequência de DNA , Cirurgia Torácica Vídeoassistida
16.
Parasit Vectors ; 10(1): 8, 2017 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-28057055

RESUMO

BACKGROUND: Plasmodium ookinete surface proteins as post-fertilization target antigens are potential malaria transmission-blocking vaccine (TBV) candidates. Putative secreted ookinete protein 25 (PSOP25) is a highly conserved ookinete surface protein, and has been shown to be a promising novel TBV target. Here, we further investigated the TBV activities of the full-length recombinant PSOP25 (rPSOP25) protein in Plasmodium berghei, and characterized the potential functions of PSOP25 during the P. berghei life-cycle. METHODS: We expressed the full-length P. berghei PSOP25 protein in a prokaryotic expression system, and developed polyclonal mouse antisera and a monoclonal antibody (mAb) against the recombinant protein. Indirect immunofluorescence assay (IFA) and Western blot were used to test the specificity of antibodies. The transmission-blocking (TB) activities of antibodies were evaluated by the in vitro ookinete conversion assay and by direct mosquito feeding assay (DFA). Finally, the function of PSOP25 during Plasmodium development was studied by deleting the psop25 gene. RESULTS: Both polyclonal mouse antisera and anti-rPSOP25 mAb recognized the PSOP25 proteins in the parasites, and IFA showed the preferential expression of PSOP25 on the surface of zygotes, retorts and mature ookinetes. In vitro, these antibodies significantly inhibited ookinetes formation in an antibody concentration-dependent manner. In DFA, mice immunized with the rPSOP25 and those receiving passive transfer of the anti-rPSOP25 mAb reduced the prevalence of mosquito infection by 31.2 and 26.1%, and oocyst density by 66.3 and 63.3%, respectively. Genetic knockout of the psop25 gene did not have a detectable impact on the asexual growth of P. berghei, but significantly affected the maturation of ookinetes and the formation of midgut oocysts. CONCLUSIONS: The full-length rPSOP25 could elicit strong antibody response in mice. Polyclonal and monoclonal antibodies against PSOP25 could effectively block the formation of ookinetes in vitro and transmission of the parasites to mosquitoes. Genetic manipulation study indicated that PSOP25 is required for ookinete maturation in P. berghei. These results support further testing of the PSOP25 orthologs in human malaria parasites as promising TBV candidates.


Assuntos
Antígenos de Protozoários/imunologia , Transmissão de Doença Infecciosa/prevenção & controle , Vacinas Antimaláricas/imunologia , Malária/prevenção & controle , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium berghei/imunologia , Proteínas de Protozoários/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/genética , Modelos Animais de Doenças , Deleção de Genes , Imunização Passiva , Camundongos , Plasmodium berghei/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo
17.
Parasit Vectors ; 9: 190, 2016 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-27038925

RESUMO

BACKGROUND: Transmission-blocking vaccines (TBVs) are a promising strategy for malaria control and elimination. However, candidate TBV antigens are currently limited, highlighting the urgency of identifying new antigens for TBV development. METHODS: Using a combination of bioinformatic analysis and functional studies in the rodent malaria model Plasmodium berghei, we identified a conserved Plasmodium protein PbPH (PBANKA_041720) containing a pleckstrin homology (PH) domain. The expression of PbPH was detected by Western blot and indirect immunofluorescence assay (IFA). The function of PbPH was tested by genetic knockout. The TB activity was confirmed by in vitro ookinete conversion assay and mosquito feeding. RESULTS: PbPH was detected in Western blot as highly expressed in sexual stages (gametocytes and ookinetes). IFA revealed localizations of PbPH on the surface of gametes, zygotes, and ookinetes. Deletion of the pbph gene did not affect asexual growth, but significantly reduced the formation of gametocytes, ookinetes, and oocysts, indicating that PbPH protein is required for parasite sexual development. Recombinant PbPH expressed and purified from bacteria elicited strong antibody responses in mice and the antibodies significantly inhibited exflagellation of male gametocytes and formation of ookinetes in a concentration-dependent manner. Mosquito feeding experiments confirmed that mosquitoes fed on mice immunized with PbPH had 13 % reduction in the prevalence of infection and almost 48 % reduction in oocyst density. CONCLUSIONS: Pbph is a highly conserved Plasmodium gene and is required for parasite sexual development. PbPH protein is expressed on the surface of gametes and ookinetes. Immunization of mice against the recombinant PbPH protein induced strong antibody responses that effectively reduced the formation of male gametes and ookinetes in vitro and blocked transmission of the parasites to mosquitoes. These results highlight PbPH as a potential TBV candidate that is worth future investigations in human malaria parasites.


Assuntos
Antígenos de Protozoários/imunologia , Transmissão de Doença Infecciosa/prevenção & controle , Vacinas Antimaláricas/imunologia , Vacinas Antimaláricas/isolamento & purificação , Malária/prevenção & controle , Plasmodium berghei/imunologia , Proteínas de Protozoários/imunologia , Animais , Antígenos de Protozoários/genética , Western Blotting , Biologia Computacional , Modelos Animais de Doenças , Técnica Indireta de Fluorescência para Anticorpo , Técnicas de Inativação de Genes , Camundongos , Plasmodium berghei/fisiologia , Proteínas de Protozoários/genética
18.
Vaccine ; 34(23): 2570-8, 2016 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-27083421

RESUMO

With a renewed hope for malaria elimination, interventions that prevent transmission of parasites from humans to mosquitoes have received elevated attention. Transmission-blocking vaccines (TBVs) targeting the sexual stages are well suited for this task. Here, through bioinformatic analysis, we selected two putative Plasmodium berghei ookinete-stage proteins (PBANKA_111920, and PBANKA_145770) and a previously characterized ookinete protein PBANKA_135340 (PSOP7) for evaluation of their transmission-blocking potentials. Fragments of these predicted proteins were expressed in bacteria and purified recombinant proteins were used to immunize mice. Antisera against these recombinant proteins recognized proteins of predicted sizes from ookinete lysates and localized their expression on the surface of ookinetes. Inclusion of these antisera in in vitro ookinete culture significantly inhibited ookinete formation. Mosquitoes fed on mice immunized with the recombinant proteins also showed significantly reduced oocyst densities (60.0-70.7%) and modest reductions of oocyst prevalence (10.7-37.4%). These data, together with the conservation of these genes in Plasmodium, suggest that these three ookinete proteins could be new promising targets for TBVs and are worth of future investigations in the human malaria parasites.


Assuntos
Antígenos de Protozoários/imunologia , Genes de Protozoários , Vacinas Antimaláricas/imunologia , Malária/prevenção & controle , Plasmodium berghei/genética , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/genética , Biologia Computacional , Culicidae , Feminino , Soros Imunes/imunologia , Malária/transmissão , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/imunologia
19.
Parasit Vectors ; 8: 615, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26627683

RESUMO

BACKGROUND: The male gamete fertilization factor P48/45 in malaria parasites is a prime transmission-blocking vaccine (TBV) candidate. Efforts to develop antimalarial vaccines are often thwarted by genetic diversity of the target antigens. Here we evaluated the genetic diversity of Pvs48/45 gene in global Plasmodium vivax populations. METHODS: We determined 200 Pvs48/45 sequences collected from temperate and subtropical parasite populations in China. Population genetic and evolutionary analyses were performed to determine the levels of genetic diversity, potential signature of selection, and population differentiation. RESULTS: Analysis of the Pvs48/45 sequences from 200 P. vivax parasites collected in a temperate and a tropical region revealed a low level of genetic diversity (π = 0.0012) with 14 single nucleotide polymorphisms, of which 11 were nonsynonymous. Analysis of 344 Pvs48/45 sequences from nine worldwide P. vivax populations detected a total of 38 haplotypes, of which 13 haplotypes were present only once. Multiple tests for selection confirmed a signature of positive selection on Pvs48/45 with selection skewed to the second cysteine domain. Haplotype network analysis and Wright's fixation index showed large geographical differentiation with the presence of continent-or region-specific mutations in this gene. CONCLUSIONS: Pvs48/45 displays low levels of genetic diversity with the presence of region-specific mutations. Some of the mutations may be potential epitope targets based on their positions in the predicted structure, highlighting the need for future evaluation of these mutations in designing Pvs48/45-based TBV.


Assuntos
Antígenos de Protozoários/genética , Variação Genética , Plasmodium vivax/genética , Vacinas Protozoárias/genética , Antígenos de Protozoários/imunologia , China , DNA de Protozoário/química , DNA de Protozoário/genética , Epitopos/genética , Epitopos/imunologia , Haplótipos , Dados de Sequência Molecular , Filogeografia , Plasmodium vivax/imunologia , Polimorfismo de Nucleotídeo Único , Vacinas Protozoárias/imunologia , Análise de Sequência de DNA
20.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 17(4): 1061-3, 2009 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-19698260

RESUMO

The objective of study was to observe the efficacy and adverse events of modified CAG regimen in treating patients with relapsed acute myeloid leukemia. CAG regimen with prolongation of aclarubicin up to 7 days were used to treat 17 cases of relapsed acute myeloid. After 1 course of chemotherapy, the efficacy and adverse events were evaluated, patients who did not achieve remission were excluded from this regimen, patients who achieved remission were continuously given 1 course of CAG regimen. The results showed that out of 17 case 8 patients achieved complete remission (CR, 47.06%) and 5 patients achieved partial remission (PR, 29.14%). Most of these cases had slight adverse events which mainly were marrow suppression that could be tolerated, overall survival was 76.47%. In conclusion, treatment for relapsed acute myeloid leukemia with modified CAG regiment is safe and effective, and can provide conditions for allo-hematopoietic stem cell transplantation, but its long term efficacy needs to further study.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Leucemia Mieloide Aguda/tratamento farmacológico , Aclarubicina , Citarabina , Fator Estimulador de Colônias de Granulócitos , Humanos , Resultado do Tratamento
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