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1.
Br J Cancer ; 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750114

RESUMO

BACKGROUND: Chemokine signaling within the tumor microenvironment can promote tumor progression. Although CCR1 and CXCR2 on myeloid cells could be involved in tumor progression, it remains elusive what effect would be observed if both of those are blocked. METHODS: We employed two syngeneic colorectal cancer mouse models: a transplanted tumor model and a liver metastasis model. We generated double-knockout mice for CCR1 and CXCR2, and performed bone marrow (BM) transfer experiments in which sub-lethally irradiated wild-type mice were reconstituted with BM from either wild-type, Ccr1-/-, Cxcr2-/- or Ccr1-/-Cxcr2-/- mice. RESULTS: Myeloid cells that express MMP2, MMP9 and VEGF were accumulated around both types of tumors through CCR1- and CXCR2-mediated pathways. Mice reconstituted with Ccr1-/-Cxcr2-/- BM exhibited the strongest suppression of tumor growth and liver metastasis compared with other three groups. Depletion of CCR1+CXCR2+ myeloid cells led to a higher frequency of CD8+ T cells, whereas the numbers of Ly6G+ neutrophils, FOXP3+ Treg cells and CD31+ endothelial cells were significantly decreased. Furthermore, treatment with a neutralizing anti-CCR1 mAb to mice reconstituted with Cxcr2-/- BM significantly suppressed tumor growth and liver metastasis. CONCLUSION: Dual blockade of CCR1 and CXCR2 pathways in myeloid cells could be an effective therapy against colorectal cancer.

2.
Sci Rep ; 13(1): 22217, 2023 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-38097649

RESUMO

Osteoprotegerin (OPG) is a secreted cytokine that functions as a decoy receptor for receptor activator of nuclear factor kappa-B (RANK) ligand (RANKL). Anti-RANKL treatment for bone metastasis has been widely accepted for solid tumors. However, the mechanism of OPG-RANKL-RANK signaling in systemic colorectal cancer (CRC) metastasis remains unclear. In this study, we investigated the relevance and function of OPG expression in CRC liver metastasis. First, we performed in silico analysis using The Cancer Genome Atlas public database and found that lower OPG expression in CRC was associated with poor overall survival. Immunohistochemistry analyses using resected specimen from patients with CRC in our institute confirmed the result. Patient-matched primary CRC and liver metastases showed a significant downregulation of OPG expression in metastatic lesions. In CRC cell lines, OPG expression did not suppress cell proliferation and migration. However, OPG expression inhibited macrophage migration by suppressing the RANKL-RANK pathway. Moreover, in vivo mouse liver metastasis models showed that OPG expression in CRC cells suppressed liver metastases. In addition, treatment with an anti-RANKL neutralizing antibody also suppressed liver metastases. These results showed that downregulation of OPG expression in CRC cells promotes liver metastasis by activating tumor-associated macrophage, which can become a candidate for targeted therapy with anti-RANKL neutralizing antibody for CRC liver metastasis.


Assuntos
Neoplasias Colorretais , Neoplasias Hepáticas , Animais , Humanos , Camundongos , Anticorpos Neutralizantes/metabolismo , Neoplasias Colorretais/genética , Regulação para Baixo , Neoplasias Hepáticas/genética , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Ligante RANK/genética , Ligante RANK/metabolismo , Receptor Ativador de Fator Nuclear kappa-B/genética , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Macrófagos Associados a Tumor/metabolismo
3.
Int J Mol Sci ; 24(2)2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36674635

RESUMO

Neutrophil extracellular traps (NETs) play important roles in host immunity, as there is increasing evidence of their contribution to the progression of several types of cancers even though their role in colorectal cancers (CRCs) remains unclear. To investigate the clinical relevance of NETs in CRCs, we examined the expression of citrullinated histone H3 using immunohistochemistry and preoperative serum myeloperoxidase-DNA complexes in CRC patients using an enzyme-linked immunosorbent assay. High expression of intratumoral or systemic NETs was found to correlate with poor relapse-free survival (RFS), for which it is an independent prognostic factor. In vitro investigations of CRC cells (HCT116, HT29) revealed that NETs did not affect their proliferation but did promote the migration of CRC cells mediated by neutrophil elastase (NE) released during NETosis to increase extracellular signal-regulated kinase (ERK) activity. In vivo experiments using nude mice (KSN/slc) revealed that NE inhibition suppressed liver metastases in CRC cells, although it did not affect the growth of subcutaneously implanted tumors. Taken together, these results suggest that NET formation correlates with poor prognoses of patients with CRC and that the inhibition of NE could be a potential therapy for CRC metastases.


Assuntos
Neoplasias Colorretais , Armadilhas Extracelulares , Animais , Camundongos , Armadilhas Extracelulares/metabolismo , Elastase de Leucócito/metabolismo , Neutrófilos/metabolismo , Camundongos Nus , Recidiva Local de Neoplasia/patologia , Neoplasias Colorretais/patologia
4.
Hum Cell ; 33(2): 397-404, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31939005

RESUMO

The objective of the study was to realize whether specific signatures for high-risk human papilloma virus (HPV) infection exist in the cytologic specimens with ASC-US judgement or not. The materials are 132 cytologic specimens with the diagnosis of ASC-US, including 56 cases with positive and 76 cases with negative HPV infection. Cytological findings are compared between two groups. Immature squamous metaplastic cells with nuclear atypia, SFT/IMT dyskaryotic cells, atypical parakeratosis, smudgy nuclei and multinucleated cells are the signature of high-risk HPV infection, whereas in the HPV(-) group immature metaplastic cells without atypia, moderately mature metaplastic cells without nuclear atypia and atrophic background are more popular. Instead, there are no differences on SFT/IMT background, microorganism infection and koilocytosis with or without nuclear atypia in both groups. The specific findings to confirm high-risk HPV infection are realized and the present results will contribute to decrease an unnecessary ASC-US judgement.


Assuntos
Células Escamosas Atípicas do Colo do Útero , Técnicas Citológicas , Infecções por Papillomavirus , Feminino , Humanos , Risco
5.
Medicine (Baltimore) ; 99(1): e18641, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31895826

RESUMO

RATIONALE: Cystic lymphangiomas are uncommon congenital malformations that originate from lymphatic channels. Lymphangiomas frequently appear in the head, neck, and axillary regions of children. Abdominal cystic lymphangiomas are extremely rare, having a reported incidence of 1 in 20,000 to 250,000. PATIENT CONCERNS: A 50-year-old female patient was admitted to our hospital with a cough that had persisted for several weeks. Abdominal ultrasonography incidentally revealed a multilocular cystic lesion in the lesser curvature of the stomach. DIAGNOSIS: Preoperative findings indicated that the lesion was cystic lymphangioma. However, the possibility of a pancreatic tumor could not be completely excluded. INTERVENTIONS: Laparoscopy revealed a multilocular cyst in the lesser curvature of the stomach. The gastrocolic ligament was divided, and the body and tail of the pancreas was exposed in the omental bursa, showing that the cystic lesion was not derived from the pancreas but from the lesser omentum. Although it was located directly beside the left gastric artery, the cyst was enucleated and totally resected laparoscopically without sacrificing the artery. OUTCOMES: The cystic lesion was histopathologically diagnosed as an abdominal cystic lymphangioma originating from the lesser omentum. The patient was discharged on the postoperative day 4 without complications. LESSONS: Preoperative imaging cannot completely distinguish abdominal cystic lymphangiomas from other types of cystic tumors. Because cystic lymphangiomas have the potential to grow, invade vital structures, and develop life-threatening complications, laparoscopic assessment followed by total resection is considered a useful treatment strategy for peripancreatic cystic lesions.


Assuntos
Neoplasias Abdominais/cirurgia , Linfangioma Cístico/cirurgia , Omento/patologia , Neoplasias Abdominais/diagnóstico por imagem , Neoplasias Abdominais/patologia , Feminino , Humanos , Laparoscopia , Linfangioma Cístico/diagnóstico por imagem , Linfangioma Cístico/patologia , Pessoa de Meia-Idade
6.
Surg Today ; 50(2): 171-177, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31363844

RESUMO

PURPOSE: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) is the active treatment for peritoneal carcinomatosis of appendiceal origin. However, surgical management is sometimes difficult in patients with a high-tumor burden. METHODS: A high-tumor burden was defined as a peritoneal cancer index (PCI) ≥ 28. Among 49 patients receiving CRS + HIPEC, 29 had a PCI ≥ 28. RESULTS: Complete cytoreduction (CC-0/1) was achieved in 20 of the 29 patients with a PCI ≥ 28 and in all 20 patients with a PCI < 28. Among the patients achieving CC-0/1, gastrectomy or total colectomy was performed more frequently, the hospital stay was longer and postoperative complications were more frequent in those with a PCI ≥ 28 than in those with a PCI < 28. If CC-0/1 was achieved, the overall survival was comparable between patients with a PCI ≥ 28 and a PCI < 28. However, the recurrence-free survival was significantly worse for patients with a PCI ≥ 28 than for those with a PCI < 28 (5-year survival: 73.7% vs. 5.9%). Patients with recurrence who underwent repeat CRS showed a better overall survival than those without repeat CRS. Among patients with a PCI ≥ 28, a performance status (PS) of 2/3 was a significant prognostic factor (hazard ratio = 5.132). CONCLUSIONS: In patients with a high-tumor burden undergoing CRS + HIPEC, postoperative complications were more frequent, and the recurrence rate was higher than in those without a high-tumor burden. Repeat CRS improved the survival of patients with recurrence. The PS was a key indicator when selecting patients suitable for aggressive resection.


Assuntos
Apêndice , Carcinoma/cirurgia , Neoplasias Peritoneais/cirurgia , Antineoplásicos/administração & dosagem , Carcinoma/mortalidade , Carcinoma/patologia , Carcinoma/terapia , Procedimentos Cirúrgicos de Citorredução/métodos , Humanos , Hipertermia Induzida , Recidiva Local de Neoplasia , Neoplasias Peritoneais/mortalidade , Neoplasias Peritoneais/patologia , Neoplasias Peritoneais/terapia , Taxa de Sobrevida
7.
Acta Cytol ; 60(5): 429-437, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27701154

RESUMO

OBJECTIVE: To evaluate whether or not the liquid-based procedure (LBP) for endometrial cytology is as worthwhile for endometrial phasing as conventional slides. MATERIALS AND METHODS: The subjects were 81 women who underwent endometrial cytology and were defined as negative. The specimens obtained by either Endocyte® or Masubuchi aspiration tube® were processed first with the conventional procedure and then with LBP using TACAS™. RESULTS: (1) The number of subjects diagnosed by the conventional method as having proliferative, mid-, middle-secretory and late-secretory and atrophic phases was 40, 11, 10, 0 and 20, respectively. The rate of agreement with those using LBP was 87.7%. (2) Incidences of large clusters, ductal clusters, palisade arrangement, uneven staining and dirty mucous background detected were significantly higher with the conventional method, whereas with LBP clean background, inconspicuous bonding of cells, scattered solitary glandular cells, clear well-stained cytoplasm and cell compactness were higher. (3) Especially in the proliferative phase, clusters tended to be smaller and lose their architectural structures, and scattered solitary columnar cells were present. (4) Cells in the mid-phase tended to have loose contact and to mimic other phases. CONCLUSIONS: Cytodiagnosis of endometrial phasing prepared with LBP is feasible to perform when some modifications are implemented.


Assuntos
Citodiagnóstico/métodos , Neoplasias do Endométrio/patologia , Endométrio/patologia , Proliferação de Células/fisiologia , Citoplasma/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Esfregaço Vaginal/métodos
8.
Acta Cytol ; 59(2): 207-12, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25925150

RESUMO

OBJECTIVE: To evaluate a fully automated processing system (TACAS™ Pro) for liquid-based procedures (LBPs). METHODS AND MATERIALS: Materials were 3,483 and additionally 502 specimens that were taken at Kanagawa Health Service Association. Specimens obtained with a Cervex-Brush® were first smeared to glass slides using one side of the brush and then processed to TACAS Pro. RESULTS: (1) The microscopy watching time per normal case was 3.65 ± 0.85 min in the conventional procedure, whereas in the LBP it was 1.95 ± 0.60 min, and the latter reduced workload to 53%. (2) The handling time of TACAS Pro per day was 2 h and 25.8 min. The workload at a laboratory offset it and revealed the work saving to be 63.8%. (3) Unsatisfactory rates were 0% in the conventional procedure, whereas in the LBP it was 1.88% at first. The latter rate decreased to 0.5% after system improvement. (4) Specimens which may disturb microscopy analysis were found in 1.06%, including 3 cases of possible carry-over of cells to the following slides. An additional study with the revised system confirmed no carry-over. (5) Incidences of abnormal cytology were consistent between the two methods. CONCLUSIONS: The revised automated processing system TACAS Pro is a feasible and useful LBP and reduces the workload of cytology laboratories.


Assuntos
Colo do Útero/patologia , Microscopia , Teste de Papanicolaou , Esfregaço Vaginal , Adulto , Automação Laboratorial , Desenho de Equipamento , Feminino , Humanos , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Análise e Desempenho de Tarefas , Fatores de Tempo , Esfregaço Vaginal/instrumentação , Fluxo de Trabalho
9.
Biosci Biotechnol Biochem ; 78(6): 969-75, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25036121

RESUMO

Basic amino acids (lysine, histidine and arginine) accumulated in Saccharomyces cerevisiae vacuoles should be mobilized to cytosolic nitrogen metabolism under starvation. We found that the decrease of vacuolar basic amino acids in response to nitrogen starvation was impaired by the deletion of AVT4 gene encoding a vacuolar transporter. In addition, overexpression of AVT4 reduced the accumulation of basic amino acids in vacuoles under nutrient-rich condition. In contrast to AVT4, the deletion and overexpression of AVT3, which encodes the closest homologue of Avt4p, did not affect the contents of vacuolar basic amino acids. Consistent with these, arginine uptake into vacuolar membrane vesicles was decreased by Avt4p-, but not by Avt3p-overproduction, whereas various neutral amino acids were excreted from vacuolar membrane vesicles in a manner dependent on either Avt4p or Avt3p. These results suggest that Avt4p is a vacuolar amino acid exporter involving in the recycling of basic amino acids.


Assuntos
Sistemas de Transporte de Aminoácidos Básicos/metabolismo , Aminoácidos Básicos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo , Vacúolos/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Sistemas de Transporte de Aminoácidos Básicos/química , Transporte Biológico , Membranas Intracelulares/metabolismo , Dados de Sequência Molecular , Proteínas de Saccharomyces cerevisiae/química
10.
J Toxicol Sci ; 39(2): 311-7, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24646713

RESUMO

Tributyltin (TBT) has long been recognized as a major environmental pollutant that can cause significant damage to the cellular functions as well as disruption of endocrine homeostasis. TBT induces apoptosis accompanied by production of reactive oxygen species (ROS) in mammalian and yeast cells. We observed that the budding yeast cells exposed to this compound at low concentrations exhibited cell growth arrest, but not cell death. Flow cytometric analysis of yeast cells without synchronization and morphological assessment of cells synchronized at M phase by nocodazole treatment indicated that TBT-exposed Saccharomyces cerevisiae cells were arrested at G1 phase of the cell cycle. This arrest was recovered by the addition of N-acetylcysteine, suggesting the involvement of ROS production by TBT. This is the first study to evaluate the action of TBT on cell cycle events.


Assuntos
Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Fase G1/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/efeitos dos fármacos , Compostos de Trialquitina/toxicidade , Apoptose/efeitos dos fármacos , Relação Dose-Resposta a Droga , Nocodazol/farmacologia
11.
Biosci Biotechnol Biochem ; 77(9): 1988-90, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24018691

RESUMO

A vacuolar membrane protein, Vba2p of Schizosaccharomyces pombe, is involved in basic amino acid uptake by intact cells. Here we found evidence that Vba2p mediated ATP-dependent lysine uptake by vacuolar membrane vesicles of Saccharomyces cerevisiae. Vba2p was also responsible for quinidine sensitivity, and the addition of lysine improved cell growth on quinidine-containing media. These findings should be useful for further characterization of Vba2p.


Assuntos
Sistemas de Transporte de Aminoácidos Básicos/genética , Sistemas de Transporte de Aminoácidos Básicos/metabolismo , Membranas Intracelulares/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/genética , Vacúolos/genética , Trifosfato de Adenosina/metabolismo , Expressão Gênica , Lisina/metabolismo
12.
Biosci Biotechnol Biochem ; 76(9): 1802-4, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22972345

RESUMO

Amino acid analysis of Saccharomyces cerevisiae cells indicated that neutral amino acids such as glycine and alanine were probably excluded from the vacuoles, and that vacuolar H(+)-ATPase (V-ATPase) was involved in the vacuolar compartmentalization of these amino acids. We found that vacuolar membrane vesicles export neutral amino acids in an ATP-dependent manner. This is important in identifying vacuolar transporters for neutral amino acids.


Assuntos
Trifosfato de Adenosina/metabolismo , Aminoácidos Neutros/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Vesículas Transportadoras/metabolismo , ATPases Vacuolares Próton-Translocadoras/metabolismo , Transporte Biológico , Membranas Intracelulares/química , Cinética , Vesículas Transportadoras/química , Vacúolos/química
13.
Acta Cytol ; 56(1): 74-9, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22236749

RESUMO

OBJECTIVE: To evaluate the usefulness of a new liquid-based cytological procedure in a population screening program for cervix cancer. SUBJECTS AND METHODS: Subjects were 1,000 women who underwent primary screening at the Kanagawa Health Service Association. The cytological specimens obtained by either cotton stick and Cytobrush® or Cervex-Brush® were processed using the Thinlayer Advanced Cytology Assay System (TACAS™), following the manufacturer's instructions. RESULTS: (1) Cells were evenly distributed on specimens and stained evenly; (2) shrinkage of cells was 5% based on measurement of the nuclear diameters of granulocytes in comparison with those of the conventional procedure; (3) incidences of cells that occupied the whole area, 1/20≤, 1/4≤, 1/4> of the observation fields were 58.8, 26.2, 12.0 and 3.0%, respectively; (4) number of the squamous cells in cases with 1/4> was <5,000, in which specimen cells were correctly obtained from the squamocolumnar junction except in 3 cases (0.3%); (5) bleeding at cellular sampling was 5%, but did not disturb cell analysis; (6) inflammation caused by organisms was easily diagnosed; (7) detection rate of abnormal cytology was 4.3%, including ASC-US in 2.8% and ASC-H in 0.1%. CONCLUSION: TACAS is a feasible and useful cytological procedure.


Assuntos
Detecção Precoce de Câncer/métodos , Neoplasias do Colo do Útero/diagnóstico , Colposcopia , Citodiagnóstico/métodos , Feminino , Humanos , Pessoa de Meia-Idade , Displasia do Colo do Útero/diagnóstico
14.
J Toxicol Sci ; 36(1): 117-20, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21297349

RESUMO

ATP-binding cassette (ABC) transporter plays an important role for resistance against xenobiotics. There are eleven ABC transporter genes in the genome of fission yeast Schizosaccharomyces pombe. We examined the role of ABC transporter against the toxicity of tributyltin chloride (TBT), a widespread environmental pollutant, in cell growth. Among individual ABC transporter mutants, the growth of a mutant deficient in Bfr1p, a plasma membrane-embedded transporter, was extremely sensitive to TBT. The lethal TBT concentration inducing 50% of cell death (LC(50)) was 25 µM for the parent strain and 10.2 µM for the bfr1∆ mutant. Thus, Bfr1p was responsible for TBT resistance in S. pombe.


Assuntos
Transportadores de Cassetes de Ligação de ATP/fisiologia , Farmacorresistência Fúngica/genética , Poluentes Ambientais/toxicidade , Proteínas de Schizosaccharomyces pombe/fisiologia , Schizosaccharomyces/efeitos dos fármacos , Compostos de Trialquitina/toxicidade
15.
Biosci Biotechnol Biochem ; 75(2): 385-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21307582

RESUMO

The fission yeast Schizosaccharomyces pombe has a homolog of the budding yeast Atg22p, which is involved in spore formation (Mukaiyama H. et al., Microbiology, 155, 3816-3826 (2009)). GFP-tagged Atg22p in the fission yeast was localized to the vacuolar membrane. Upon disruption of atg22, the amino acid levels of the cellular fraction as well as the vacuolar fraction decreased. The uptake of several amino acids, such as lysine, histidine, and arginine, was impaired in atg22Δ cells. S. pombe Atg22p plays an important role in the compartmentalization of amino acids.


Assuntos
Aminoácidos/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/citologia , Schizosaccharomyces/metabolismo , Vacúolos/metabolismo , Proteínas Relacionadas à Autofagia , Transporte Biológico
16.
Biosci Biotechnol Biochem ; 74(10): 2166-9, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20944394

RESUMO

A recent study filling the gap in the genome sequence in the left arm of chromosome 2 of Schizosaccharomyces pombe revealed a homolog of budding yeast Vba2p, a vacuolar transporter of basic amino acids. GFP-tagged Vba2p in fission yeast was localized to the vacuolar membrane. Upon disruption of vba2, the uptake of several amino acids, including lysine, histidine, and arginine, was impaired. A transient increase in lysine uptake under nitrogen starvation was lowered by this mutation. These findings suggest that Vba2p is involved in basic amino acid transport in S. pombe under diverse conditions.


Assuntos
Aminoácidos Básicos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Transporte Biológico , Desoxiglucose/metabolismo , Nitrogênio/deficiência , Schizosaccharomyces/citologia
17.
J Toxicol Sci ; 34(5): 541-5, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19797862

RESUMO

Tributyltin chloride (TBT), an environmental pollutant, is toxic to a variety of eukaryotic and prokaryotic organisms. Although it has been reported that TBT induces apoptotic cell death in mammalian, the action of TBT on eukaryotic microorganisms has not yet been fully investigated. In this study we examined the mechanism involved in cell death caused by TBT exposure in Saccharomyces cerevisiae. The median lethal concentration of TBT was 10 microM for the parent strain BY4741 and 3 microM for the pdr5Delta mutant defective in a major multidrug transporter, respectively. Fluorescence microscopic observations revealed nuclear condensation and chromatin fragmentation in cells treated with TBT indicating that cells underwent an apoptosis-like cell dearth. TBT-induced cell death was suppressed by deletion of the yca1 gene encoding a homologue of the mammalian caspase. In parallel, reactive oxygen species (ROS) were produced by TBT. These results suggest that TBT induces apoptosis-like cell death in yeast via an Yca1p-dependent pathway possibly downstream of the ROS production. This is the first report on TBT-induced apoptotic cell death in yeast.


Assuntos
Caspases/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Compostos de Trialquitina/toxicidade , Genes Fúngicos/efeitos dos fármacos , Saccharomyces cerevisiae/genética
18.
J Toxicol Sci ; 34(5): 575-9, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19797867

RESUMO

Tributyltin chloride (TBT), an environmental pollutant, is toxic to a variety of eukaryotic and prokaryotic organisms. Some members of F-ATP synthase (F-ATPase)/vacuolar type ATPase (V-ATPase) superfamily have been identified as the molecular target of this compound. TBT inhibited the activities of H(+)-transporting or Na(+)-transporting F-ATPase as well as H(+)-transporting V-ATPase originated from various organisms. However, the sensitivity to TBT of Na(+)-transporting V-ATPase has not been investigated. We examined the effect of TBT on Na(+)-transporting V-ATPase from an eubacterium Enterococus hirae. The ATP hydrolytic activity of E. hirae V-ATPase in purified form as well as in membrane-bound form was little inhibited by less than 10 microM TBT; IC50 for TBT inhibition of purified enzyme was estimated to be about 35 microM. Active sodium transport by E. hirae cells, indicating the in vivo activity of this V-ATPase, was not inhibited by 20 microM TBT. By contrast, IC50 of H(+)-transporting V-ATPase of the vacuolar membrane vesicles from Saccharomyces cerevisiae was about 0.2 microM. E. hirae V-ATPase is thus extremely less sensitive to TBT.


Assuntos
Adenosina Trifosfatases/efeitos dos fármacos , Proteínas de Bactérias/efeitos dos fármacos , Enterococcus/enzimologia , Transporte de Íons/efeitos dos fármacos , Compostos de Trialquitina/toxicidade , Trifosfato de Adenosina/metabolismo , Enterococcus/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo
19.
Anim Cogn ; 12(1): 193-9, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18712531

RESUMO

This study investigated whether Asian elephants can make relative quantity judgment (RQJ), a dichotomous judgment of unequal quantities ordered in magnitude. In Experiment 1, elephants were simultaneously shown two baskets with differing quantities of bait (up to 6 items). In Experiment 2, elephants were sequentially presented with baits, which could not be seen by elephants in their total quantities. The task of elephants was to choose the larger quantity in both experiments. Results showed that the elephants chose the larger quantity with significantly greater frequency. Interestingly, the elephants did not exhibit disparity or magnitude effects, in which performance declines with a smaller difference between quantities in a two-choice task, or the total quantity increases, respectively. These findings appear to be inconsistent with the previous reports of RQJ in other animals, suggesting that elephants may be using a different mechanism to compare and represent quantities than previously suggested for other species.


Assuntos
Formação de Conceito , Elefantes/psicologia , Julgamento , Conceitos Matemáticos , Resolução de Problemas , Animais , Comportamento de Escolha , Feminino , Masculino , Matemática , Reconhecimento Visual de Modelos , Aprendizagem Seriada
20.
Anim Cogn ; 11(2): 359-65, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18087732

RESUMO

The present study explores to what extent Asian elephants show "means-end" behavior. We used captive Asian elephants (N = 2) to conduct four variations of the Piagetian "support" problem, which involves a goal object that is out of reach, but rests on a support within reach. In the first condition, elephants were simultaneously presented with two identical trays serving as the "support", with the bait on one tray and the other tray left empty. In the next two conditions, the bait was placed on one tray, while additional bait was placed beside the other tray. In the last condition, both trays contained bait, but one of the trays had a small gap which prevented the elephants from reaching the reward. Subjects were required to choose and pull either tray with their trunk and to obtain the bait (i.e. goal). Results showed that one elephant performed all of the support problems significantly above chance after several sessions, suggesting that the elephant was capable of understanding that pulling the tray was the "means" for achieving the "end" of obtaining the bait. This study showed that elephants show means-end behavior when subjected to a Piagetian "support" task, and indicates that such goal-directed behavior occurs in species other than primates.


Assuntos
Formação de Conceito , Elefantes/psicologia , Objetivos , Resolução de Problemas , Comportamento de Utilização de Ferramentas , Animais , Compreensão , Feminino
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