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OBJECTIVE: To evaluate the efficacy and prognostic significance of reperfusion therapy in patients with Trousseau syndrome-related cerebral infarction. STUDY DESIGN: Descriptive study. Place and Duration of the Study: Department of Neurology, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China, and The Second Affiliated Hospital of Xiamen Medical College, Xiamen, China, between January 2017 and December 2023. METHODOLOGY: Patients with Trousseau-associated cerebral infarction who were treated at two hospitals were included in the study. Clinical outcomes, including early neurological deterioration, intracranial haemorrhage, in-hospital mortality, 90-day modified Rankin scale (mRS) score, 90-day mortality, initial and discharge National Institutes of Health Stroke Scale (NIHSS) score, and ΔNIHSS (difference between the initial and discharge NIHSS score), were compared between the reperfusion-treated group (n = 9) and the conventionally treated group (n = 23). RESULTS: Patients who received reperfusion therapy demonstrated significant neurological improvement at discharge, with a statistically significant difference in their ΔNIHSS scores compared to those of the conventionally treated group (p <0.001). No significant differences were observed in early neurological deterioration (11.10% vs. 13.00%, p = 1.000), intracranial haemorrhage (33.33% vs. 8.70%, p = 0.121), in-hospital mortality (22.20% vs. 26.10%, p = 1.000), 90-day mortality (55.60% vs. 87.00%, p = 0.076), or 90-day mRS score (p = 0.052) between the two groups. CONCLUSION: Despite the high mortality rate within 90 days, reperfusion therapy has the potential to improve the quality of life of surviving cancer patients with Trousseau-associated cerebral infarction. KEY WORDS: Trousseau syndrome-related cerebral infarction, Reperfusion therapy, Intravenous thrombolysis, Mechanical thrombectomy, Acute cerebral infarction.
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Infarto Cerebral , Reperfusión , Humanos , Masculino , Femenino , Persona de Mediana Edad , Reperfusión/métodos , Infarto Cerebral/terapia , Anciano , Pronóstico , Estudios de Casos y Controles , Resultado del Tratamiento , Mortalidad Hospitalaria , China/epidemiología , SíndromeRESUMEN
Floral spurs, widely recognized as a classic example of key morphological and functional innovation and thought to have promoted the origin and adaptive evolution of many flowering plant lineages, have attracted the attention of researchers for centuries. Despite this, the mechanisms underlying the development and evolution of these structures remain poorly understood. Recent studies have discovered the phytohormones and transcription factor genes that play key roles in regulating patterns of cell division and cell expansion during spur morphogenesis. Spur morphogenesis was also found to be tightly linked with the programs specifying floral zygomorphy, floral organ identity determination, and nectary development. Independent origins and losses of spurs in different flowering plant lineages, therefore, may be attributed to changes in the spur program and/or its upstream ones.
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RATIONALE: Argon gas poisoning is an often overlooked yet critical public health concern with the potential for severe and persistent neurological consequences. Current treatment protocols primarily focus on acute-phase management, but a comprehensive understanding of the long-term neurological effects remains incomplete. PATIENT CONCERNS: A 22-year-old male worker was found unconscious in the furnace room of an argon production facility. After regaining consciousness, he presented with symptoms of dizziness, headache, fatigue, and irritability. Neurological examination revealed impairments in both recent and remote memory, notably pronounced short-term memory deficits and reduced arithmetic skills. DIAGNOSIS: Argon gas poisoning, hypoxic encephalopathy, and mild hepatic and renal dysfunction. INTERVENTIONS: Upon admission, symptomatic supportive measures included oxygen therapy via nasal cannula (3 L/min), daily hyperbaric oxygen therapy (1.5 ATA, 60 minutes), oral neurotrophic methylcobalamin (0.5 mg, 3 times daily), and intravenous vitamin C infusion (2 g daily) to scavenge oxygen free radicals. OUTCOME: A 2-year telephone follow-up indicated persistent short-term memory impairment, particularly with memorizing numbers. In a memory test, he achieved a digit span forward of 5 but a digit span backward of 2, indicating impairment. Despite these challenges, his daily life and work performance remained largely unaffected. LESSON: This case offers valuable insights into the biological mechanisms underlying prolonged neurological sequelae following asphyxiating gas exposure, specifically the persistent impairment of hippocampal function.
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Argón , Trastornos de la Memoria , Humanos , Masculino , Trastornos de la Memoria/inducido químicamente , Trastornos de la Memoria/terapia , Adulto Joven , Oxigenoterapia Hiperbárica/métodos , Hipoxia Encefálica/inducido químicamente , Hipoxia Encefálica/terapiaRESUMEN
BACKGROUND: Calmodulin 2 (CALM2) belongs to the highly conserved calcium-binding protein family, implicated in the pathogenesis of various malignant tumors. However, its involvement in breast cancer (BRCA) remains unclear. This study aimed to examine CALM2 expression in BRCA and its associations with prognosis, clinicopathological features, protein-protein interactions, and immune cell infiltration. MATERIALS AND METHODS: Online bioinformatics tools were employed to assess CALM2 expression and its clinical relevance in BRCA. Western blotting and immunohistochemistry were utilized to evaluate CALM2 expression in BRCA cell lines and tissues. Logistic regression was applied to analyze the relationship between CALM2 expression levels and clinicopathological parameters. Transwell assay was performed to validate the role of CALM2 in BRCA migration and invasion. RESULTS: CALM2 expression was significantly elevated in BRCA, with increased levels predicting poor overall survival (OS) and disease-free survival (DFS). Moreover, high CALM2 expression correlated with poorer DFS specifically in triple-negative breast cancer (TNBC). CALM2 expression in BRCA showed significant associations with lymph node metastasis, TP53 mutation status, and menopause status. Silencing CALM2 in BRCA cells demonstrated inhibition of cell migration and invasion in vitro. CONCLUSIONS: CALM2 is overexpressed in BRCA and its upregulation is significantly correlated with poor patient prognosis. Elevated CALM2 expression holds promise as a potential molecular marker for predicting poor survival and as a therapeutic target in BRCA.
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Biomarcadores de Tumor , Neoplasias de la Mama , Calmodulina , Humanos , Femenino , Calmodulina/metabolismo , Calmodulina/genética , Pronóstico , Persona de Mediana Edad , Neoplasias de la Mama/patología , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/metabolismo , Biomarcadores de Tumor/metabolismo , Biomarcadores de Tumor/análisis , Adulto , Movimiento Celular , Anciano , Supervivencia sin Enfermedad , Regulación Neoplásica de la Expresión Génica , Línea Celular TumoralRESUMEN
Peltate organs, such as the prey-capturing traps of carnivorous plants and nectary-bearing petals of ranunculaceous species, are widespread in nature and have intrigued and perplexed scientists for centuries. Shifts in the expression domains of adaxial/abaxial genes have been shown to control leaf peltation in some carnivorous plants, yet the mechanisms underlying the generation of other peltate organs remain unclear. Here, we show that formation of various peltate ranunculaceous petals was also caused by shifts in the expression domains of adaxial/abaxial genes, followed by differentiated regional growth sculpting the margins and/or other parts of the organs. By inducing parameters to specify the time, position, and degree of the shifts and growth, we further propose a generalized modeling system, through which various unifacial, bifacial, and peltate organs can be simulated. These results demonstrate the existence of a hierarchical morphospace system and pave the way to understand the mechanisms underlying plant organ diversification.
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Regulación de la Expresión Génica de las Plantas , Hojas de la Planta , Hojas de la Planta/genética , Morfogénesis/genéticaRESUMEN
Species of the tribe Delphinieae (Ranunculaceae) have long been the focus of morphological, ecological, and evolutionary studies due to their highly specialized, nearly zygomorphic (bilaterally symmetrical) spiral flowers with nested petal and sepal spurs and reduced petals. The mechanisms underlying the development and evolution of Delphinieae flowers, however, remain unclear. Here, by conducting extensive phylogenetic, comparative transcriptomic, expression, and functional studies, we clarified the evolutionary histories, expression patterns, and functions of floral organ identity and symmetry genes in Delphinieae. We found that duplication and/or diversification of APETALA3-3 (AP3-3), AGAMOUS-LIKE6 (AGL6), CYCLOIDEA (CYC), and DIVARICATA (DIV) lineage genes was tightly associated with the origination of Delphinieae flowers. Specifically, an AGL6-lineage member (such as the Delphinium ajacis AGL6-1a) represses sepal spur formation and petal development in the lateral and ventral parts of the flower while determining petal identity redundantly with AGL6-1b. By contrast, two CYC2-like genes, CYC2b and CYC2a, define the dorsal and lateral-ventral identities of the flower, respectively, and form complex regulatory links with AP3-3, AGL6-1a, and DIV1. Therefore, duplication and diversification of floral symmetry genes, as well as co-option of the duplicated copies into the preexisting floral regulatory network, have been key for the origin of Delphinieae flowers.
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Flores , Duplicación de Gen , Ranunculaceae , Flores/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas/genética , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ranunculaceae/genéticaRESUMEN
The purpose of this study was to test the ability of DNA barcoding to identify the herbal raw trade of Tibetan medicine Dida in China. A reference database for plant-material DNA barcodes was successfully constructed and used to identify 36 commercially samples of Dida collected from Southwest China. The ITS sequence was amplified from these samples and the efficiency of the PCR amplification of ITS was 100%. The DNA sequencing results revealed that 3 samples (8.3%) were authenticated as Swertia chirayita, 2 sequences (5.6%) were authenticated as Swertia mussotii, 3 sequences (8.3%) were authenticated as Swertia ciliata, as recorded in the Tibetan Pharmacopeia. The other samples were authenticated as adulterants and all of them originated from common plants belonging to Saxifraga, Swertia and Halenia. This result indicates Dida pieces that are available in the market have complex origins and may indicate a potential safety issue and DNA barcoding is a convenient tool for market supervision.
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Código de Barras del ADN Taxonómico/métodos , ADN de Plantas/genética , Medicamentos Herbarios Chinos/análisis , Swertia/clasificación , Secuencia de Bases , ADN Intergénico/genética , Bases de Datos Factuales , Medicamentos Herbarios Chinos/clasificación , Medicina Tradicional Tibetana , Filogenia , Reacción en Cadena de la Polimerasa , Swertia/genéticaRESUMEN
The small chemical compound 8-ethoxy-2-(4-fluorophenyl)-3-nitro-2H-chromene (S14161) was recently identified as an inhibitor of phosphoinositide 3-kinase (PI3K) and reported to inhibit tumor growth. However, its chiral structure and poor solubility prevent its further use. Compound 6-bromo-8-ethoxy-3-nitro-2H-chromene (BENC-511) is an analogue of S14161 produced by structural optimization. A previous study indicated that BENC-511 acted on multiple myeloma and that it had a toxicity by inhibiting the PI3K/protein kinase B (Akt) pathway. However, the effects of BENC-511 on the proliferation and apoptosis of A549 human lung adenocarcinoma cells have not been reported. The current study investigated the effects of BENC-511 on the proliferation and apoptosis of A549 cells in vitro. Results indicated that the compound BENC-511 inhibited the viability of A549 cells in a concentration- and time- dependent manner. BENC-511 suppressed proliferation and colony formation via S phase arrest. BENC-511 decreased the expression of cyclin A, proliferating cell nuclear antigen (PCNA), B-cell lymphoma-2 (Bcl-2), phospho-mammalian target of rapamycin (p-mTOR), and phospho-Akt (p-Akt) and it increased the expression of p21WAF1CIP1(p21), Caspase-3 and Caspase-9. In conclusion, BENC-511 inhibited the proliferation of A549 human lung adenocarcinoma cells via S phase arrest as a result of up-regulation of p21 and reduction of Cyclin A/cyclin-dependent kinase 2 (CDK2)/PCNA complex and it induced apoptosis by reducing the mitochondrial membrane potential via the Akt/Bcl-2/Caspase-9 mitochondrial pathway of apoptosis.
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Adenocarcinoma/tratamiento farmacológico , Antineoplásicos/uso terapéutico , Benzopiranos/uso terapéutico , Neoplasias Pulmonares/tratamiento farmacológico , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Células A549 , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Benzopiranos/farmacología , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Inhibidores de las Quinasa Fosfoinosítidos-3RESUMEN
Breast cancer is one of the most serious malignant tumors that harm to women's health. Vasculogenic mimicry (VM) is an alternative type of blood supplement independent of endothelial vessels, which refers to the formation of tumor cell-lined vessels and is associated with tumor invasion, metastasis and poor cancer patient prognosis. Prior antiangiogenic therapy just focused on vascular endothelial cells and did not significantly affect VM. DMBT, 6, 6'-bis (2, 3-dimethoxybenzoyl)-a, a-D-trehalose, has shown to have multiple anti-tumor invasion and metastasis activities; however the exact mechanism is not thoroughly elucidated. In this study, we examined key molecular mechanisms underlying VM by using breast cancer cells MDA-MB-231 and MCF-7. We found that following the hypoxia treatment, the cells were easily to form VM networks and DMBT could inhibit VM formation of both MDA-MB-231 and MCF-7 cells in hypoxic condition. When tumor cells exposed to hypoxia environment, the expression of VM related proteins such as HIF-1α, VE-cadherin, MMP-9, Cdc42, and EGFR, p-Akt, p-mTOR were increased but decreased when exposed to hypoxia medium with DMBT. In MDA-MB-231 cells, DMBT inhibit hypoxia-induced VM by suppress HIF-1α/VE-cadherin/MMPs signaling pathway and in MCF-7 cells, DMBT had little effect on HIF-1α or VE-cadherin but could inhibit cell autophagy to suppress VM formation. These results suggested that DMBT could serve as a therapeutic agent to inhibit VM formation in human breast cancer.
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Antineoplásicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Hipoxia/tratamiento farmacológico , Neovascularización Patológica/tratamiento farmacológico , Inhibidores de la Angiogénesis/farmacología , Animales , Antígenos CD/metabolismo , Neoplasias de la Mama/metabolismo , Cadherinas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Receptores ErbB/metabolismo , Femenino , Humanos , Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Células MCF-7 , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Neovascularización Patológica/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Tumors require a blood supply for survival, growth, and metastasis. It is widely accepted that the development of the tumor microcirculation compartment need the production of new blood vessels (angiogenesis). Vasculogenic mimicry (VM) is an alternative type of blood supplement independent of endothelial vessels which refers to the formation of tumor cell-lined vessels and is associated with tumor invasion, metastasis and poor cancer patient prognosis. Although a variety of proteins and microenvironmental factors are known to contribute to VM, the mechanisms underlying its formation remain unclear. The induction of VM seems to be related to hypoxia, which may promote the plastic, transendothelial phenotype of tumor cells capable of VM. Here, with regard to the above aspects, we review the advanced research on VM including molecular mechanisms and its clinical significance; and explore the development of VM-related strategies which are being utilized for anticancer treatment.
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Hipoxia/patología , Neoplasias/patología , Neoplasias/terapia , Neovascularización Patológica/metabolismo , Neovascularización Patológica/patología , Transducción de Señal , Animales , Autofagia , Transición Epitelial-Mesenquimal , Humanos , Neoplasias/metabolismoRESUMEN
Luteolin-7-O-glucoside (LUTG) was isolated from the plants of Dracocephalum tanguticum Maxim. Previous research has showed that LUTG pretreatment had a significant protective effect against doxorubicin (DOX)-induced cardiotoxicity by reducing intracellular calcium overload and leakage of creatine kinase and lactate dehydrogenase. But the underlying mechanisms have not been completely elucidated. In the present study, we investigated the effects of LUTG on H9c2 cell morphology, viability, apoptosis, reactive oxygen species generation, and the mitochondrial transmembrane potentials. The expression of p-PTEN, p-Akt, p-ERK, p-mTOR, and p-GSK-3ß were detected by Western blotting. Compared with DOX alone treatment group, the morphological injury and apoptosis of the cells in groups treated by DOX plus LUTG were alleviated, cell viability was increased, ROS generation was lowered remarkably, and mitochondrial depolarization was mitigated. In DOX group, the expression of p-PTEN was lower than normal group and the expression of p-Akt and p-ERK was higher than normal group. In the groups treated with LUTG (20 µM), the expression of p-PTEN was upregulated and the expression of p-Akt, p-ERK, p-mTOR, and p-GSK-3ß was downregulated. These results indicated that the protective effects of LUTG against DOX-induced cardiotoxicity may be related to anti-apoptosis through PTEN/Akt and ERK pathway.
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Cardiotónicos/farmacología , Doxorrubicina/toxicidad , Flavonas/farmacología , Glucósidos/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Fosfohidrolasa PTEN/biosíntesis , Proteínas Proto-Oncogénicas c-akt/biosíntesis , Animales , Antibióticos Antineoplásicos/toxicidad , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Relación Dosis-Respuesta a Droga , Sistema de Señalización de MAP Quinasas/fisiología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , RatasRESUMEN
Ectopic liver (EL) tissue is a rare entity which is reported to occur in several organs such as the gallbladder, pancreas and some other places. The EL tissue is usually detected incidentally during laparoscopy or autopsy, and several potential mechanisms may explain the development of liver ectopia. Although ectopic liver tissue is usually asymptomatic, it develops the same pathologic conditions as orthotopic liver. Although incidental ectopic livers rarely existing and do not have clinical importance, they should be looked for during electron microscope scan and histopathological examination should be carried out to rule out pathological changes since development of hepatocellular carcinoma is a possible issue. In this article, we presented an EL tissue in stomach of which only two cases were reported previously and this is the first reported case of a laparoscopically treated EL which lies to the bottom submucosal of the stomach. It would seem sensible to resect the ectopic tissue under endoscopic and the patient was well when seen for follow-up three months later.
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Coristoma/patología , Hígado , Gastropatías/patología , Adulto , Femenino , HumanosRESUMEN
A multiple xylanase system with high levels of xylanase activity produced from Penicillium oxalicum GZ-2 using agricultural waste as a substrate has been previously reported. However, the eco-physiological properties and origin of the multiplicity of xylanases remain unclear. In the present study, eight active bands were detected using zymography, and all bands were identified as putative xylanases using MALDI-TOF-MS/MS. These putative xylanases are encoded by six different xylanase genes. To evaluate the functions and eco-physiological properties of xylanase genes, xyn10A, xyn11A, xyn10B and xyn11B were expressed in Pichia pastoris. The recombinant enzymes xyn10A and xyn10B belong to the glycoside hydrolase (GH) family 10 xylanases, while xyn11A and xyn11B belong to GH11 xylanases. Biochemical analysis of the recombinant proteins revealed that all enzymes exhibited xylanase activity against xylans but with different substrate specificities, properties and kinetic parameters. These results demonstrated that the production of multiple xylanases in P. oxalicum GZ-2 was attributed to the genetic redundancy of xylanases and the post-translational modifications, providing insight into a more diverse xylanase system for the efficient degradation of complex hemicelluloses.
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Proteínas Bacterianas/metabolismo , Penicillium/enzimología , Xilosidasas/metabolismo , Secuencia de Aminoácidos , Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Clonación Molecular , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Cinética , Datos de Secuencia Molecular , Penicillium/clasificación , Filogenia , Pichia/metabolismo , Estabilidad Proteica , Proteínas Recombinantes/análisis , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Alineación de Secuencia , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Especificidad por Sustrato , Temperatura , Xilanos/metabolismo , Xilosidasas/análisis , Xilosidasas/genéticaRESUMEN
As a continuous research for the discovery of trehalose-based anti-invasive agents, we developed a convenient synthetic approach for the preparation of 6,6'-dideoxy-6,6'-bis(acylamino)-α,α-D-trehaloses. A series of trehalose-based amides were prepared through the trityl protection of the two primary hydroxyls of α,α-D-trehalose, benzoylation, the removal of the trityl protective group, mesylation, azidation, catalytic hydrogenation in the presence of hydrochloride, coupling reaction with a variety of acids, and subsequent debenzoylation and deacetylation in some cases. Compound 8b, 6,6'-dideoxy-6,6'-bis(2-hydroxybenzamide)-α,α-D-trehalose, was just as potent as the natural brartemicin against the invasion of murine colon 26-L5 cells. It exhibited no cytotoxicity on human breast adenocarcinoma MDA-MB-231 and murine colon 26-L5 cells. It can significantly inhibit the migration and invasion of the MDA-MB-231 cells. The anti-invasive effect of 8b was possibly related to its inhibitory activity on MMP-9, its suppression on the expression of MMP-9 and VEGF, and its deactivation of Akt.
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Antineoplásicos/química , Antineoplásicos/farmacología , Movimiento Celular/efectos de los fármacos , Invasividad Neoplásica/prevención & control , Neoplasias/tratamiento farmacológico , Trehalosa/análogos & derivados , Trehalosa/farmacología , Animales , Línea Celular Tumoral , Humanos , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Neoplasias/metabolismo , Neoplasias/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
BACKGROUND: Agricultural residue is more efficient than purified cellulose at inducing lignocellulolytic enzyme production in Penicillium oxalicum GZ-2, but in Trichoderma reesei RUT-C30, cellulose induces a more efficient response. To understand the reasons, we designed an artificially simulated plant biomass (cellulose plus xylan) to study the roles and relationships of each component in the production of lignocellulolytic enzymes by P. oxalicum GZ-2. RESULTS: The changes in lignocellulolytic enzyme activity, gene expression involving (hemi)cellulolytic enzymes, and the secretome of cultures grown on Avicel (A), xylan (X), or a mixture of both (AX) were studied. The addition of xylan to the cellulose culture did not affect fungal growth but significantly increased the activity of cellulase and hemicellulase. In the AX treatment, the transcripts of cellulase genes (egl1, egl2, egl3, sow, and cbh2) and hemicellulase genes (xyl3 and xyl4) were significantly upregulated (P <0.05). The proportion of biomass-degrading proteins in the secretome was altered; in particular, the percentage of cellulases and hemicellulases was increased. The percentage of cellulases and hemicellulases in the AX secretome increased from 4.5% and 7.6% to 10.3% and 21.8%, respectively, compared to the secretome of the A treatment. Cellobiohydrolase II (encoded by cbh2) and xylanase II (encoded by xyl2) were the main proteins in the secretome, and their corresponding genes (cbh2 and xyl2) were transcripted at the highest levels among the cellulolytic and xylanolytic genes. Several important proteins such as swollenin, cellobiohydrolase, and endo-beta-1,4-xylanase were only induced by AX. Bray-Curtis similarity indices, a dendrogram analysis, and a diversity index all demonstrated that the secretome produced by P. oxalicum GZ-2 depended on the substrate and that strain GZ-2 directionally adjusted the compositions of lignocellulolytic enzymes in its secretome to preferably degrade a complex substrate. CONCLUSION: The addition of xylan to the cellulose medium not only induces more hemicellulases but also strongly activates cellulase production. The proportion of the biomass-degrading proteins in the secretome was altered significantly, with the proportion of cellulases and hemicellulases especially increased. Xylan and cellulose have positively synergistic effects, and they play a key role in the induction of highly efficient lignocellulolytic enzymes.
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BACKGROUND: Endo-1,4-ß-mannanase is an enzyme that can catalyze the random hydrolysis of ß-1, 4-mannosidic linkages in the main chain of mannans, glucomannans and galactomannans and has a number of applications in different biotechnology industries. Penicillium oxalicum is a powerful hemicellulase-producing fungus (Bioresour Technol 123:117-124, 2012); however, few previous studies have focused on the cloning and expression of the endo-1,4-ß-mannanase gene from Penicillium oxalicum. RESULTS: A gene encoding an acidophilic thermostable endo-1,4-ß-mannanase (E.C. 3.2.1.78) from Penicillium oxalicum GZ-2, which belongs to glycoside hydrolase family 5, was cloned and successfully expressed in Pichia pastoris GS115. A high enzyme activity (84.4 U mL(-1)) was detected in the culture supernatant. The recombinant endo-1,4-ß-mannanase (rPoMan5A) was tagged with 6 × His at its C-terminus and purified using a Ni-NTA Sepharose column to apparent homogeneity. The purified rPoMan5A showed a single band on SDS-PAGE with a molecular mass of approximately 61.6 kDa. The specific activity of the purified rPoMan5A was 420.9 U mg(-1) using locust bean gum as substrate. The optimal catalytic temperature (10 min assay) and pH value for rPoMan5A are 80 °C and pH 4.0, respectively. The rPoMan5A is highly thermostable with a half-life of approximately 58 h at 60 °C at pH 4.0. The K m and V max values for locust bean gum, konjac mannan, and guar gum are 7.6 mg mL(-1) and 1425.5 µmol min(-1) mg(-1), 2.1 mg mL(-1) and 154.8 µmol min(-1) mg(-1), and 2.3 mg mL(-1) and 18.9 µmol min(-1) mg(-1), respectively. The enzymatic activity of rPoMan5A was not significantly affected by an array of metal ions, but was inhibited by Fe(3+) and Hg(2+). Analytical results of hydrolytic products showed that rPoMan5A could hydrolyze various types of mannan polymers and released various mannose and manno-oligosaccharides, with the main products being mannobiose, mannotriose, and mannopentaose. CONCLUSION: Our study demonstrated that the high-efficient expression and secretion of acid stable and thermostable recombinant endo-1, 4-ß-mannanase in Pichia pastoris is suitable for various biotechnology applications.