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1.
Microbiol Resour Announc ; 13(4): e0069523, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38415643

RESUMO

The genome sequence of Lentilactobacillus buchneri subsp. silagei MGR2-32, isolated from guinea grass silage, is 2,540,137 bp, has a GC content of 44%, and contains 2,393 predicted protein-coding genes. Pairwise average nucleotide identity and digital DNA-DNA hybridization values between MGR2-32 and the type strain were 99.75% and 99.90%, respectively.

2.
Auris Nasus Larynx ; 51(2): 401-405, 2023 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-37666746

RESUMO

OBJECTIVE: In the present study, we examined the effects of high-dose betahistine on dizziness handicap inventory (DHI) scores in patients with unilateral vestibulopathy. METHODS: An uncontrolled, open-label, multicenter clinical trial was conducted. Fifteen patients with unilateral vestibulopathy, such as vestibular neuritis, who complained of intractable dizziness for more than three months were enrolled. Initially, all patients were orally administered betahistine at a dose of 36 mg/day for four weeks, which is the standard dose and dosing period for the treatment of dizziness in Japan. The patients were then administered betahistine at a double dose of 72 mg/day for four weeks. Six patients who became aware of the benefits of high-dose betahistine were further administered betahistine at 72 mg/day for an additional 12 weeks (a total of 16 weeks). Perceived disability due to dizziness was assessed by DHI scores. RESULTS: In all 15 patients, short-term administration with high-dose (72 mg/day) betahistine for four weeks, but not low-dose betahistine (36 mg/day) for four weeks significantly decreased DHI scores. In particular, in six responding patients with self-reported benefits after short-term administration with high-dose betahistine, long-term administration with high-dose betahistine for 16 weeks further significantly decreased DHI scores. However, DHI scores of the remaining nine non-responding patients were not changed after short-term administration with high-dose betahistine for four weeks. CONCLUSION: Short-term administration with the standard dose and dosing period of betahistine did not improve DHI scores in the enrolled patients, indicating that they were not compensated for unilateral vestibulopathy with intractable dizziness. The present findings suggest that long-term administration with high-dose betahistine facilitates vestibular compensation to improve intractable dizziness in some, but not all patients with uncompensated unilateral vestibulopathy.

3.
J Clin Med ; 12(13)2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37445325

RESUMO

BACKGROUND: Few studies have reported on the etiology, severity, or device usage of unilateral sensorineural hearing loss (UHL) compared to bilateral hearing loss. Therefore, this study investigated the characteristics of UHL in adults and children. METHODS: We performed a survey using questionnaires for secondary and tertiary otolaryngology institutions. RESULTS: We included 15,981 patients (1549 children and 14,432 adults) from 196 institutions with otolaryngology residency programs and 2844 patients (336 children and 2508 adults) from 27 institutions with board members of the Japan Audiology Society. The latter submitted audiological data. Among children, most diagnoses were made at age 0. Approximately half of them had profound hearing loss, and 37 children (2.2%) used hearing devices. Among adults, the number of cases increased with age, but decreased when people reached their 80s and 90s. More than half of them had moderate hearing loss. Sudden sensorineural hearing loss was the most common cause of UHL of all ages; 4.4% of UHL patients used hearing devices, and most of the device users (98.6%) selected a conventional hearing aid. CONCLUSIONS: Hearing aid use is limited in children and adults with UHL in Japan. There could be many candidates with UHL for intervention such as a cochlear implant.

4.
Microbiol Resour Announc ; 12(4): e0081422, 2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-36971556

RESUMO

The whole-genome sequence of strain K-4, isolated from grass silage in Thailand, which constitutes a chromosome and two plasmids, is 2,914,933 bp long, has a GC content of 37.5%, and contains 2,734 predicted protein-coding genes. Average nucleotide identity based on BLAST+ (ANIb) and digital DNA-DNA hybridization (dDDH) values indicated that the strain K-4 was closely related to Enterococcus faecalis.

5.
Oncol Lett ; 25(3): 121, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36844630

RESUMO

Vestibular schwannoma (VS) is the most common tumor of the cerebellopontine angle. Despite the increasing diagnosis of sporadic VS over the past decade, the use of traditional microsurgeries to treat VS has decreased. This is likely a result of the adoption of serial imaging as the most common initial evaluation and treatment strategy, especially for small-sized VS. However, the pathobiology of VSs remains unclear, and elucidating the genetic information of tumor tissue may reveal novel insights. The present study performed a comprehensive genomic analysis of all exons in the key tumor suppressor and oncogenes from 10 small (<15 mm) sporadic VS samples. The evaluations identified NF2, SYNE1, IRS2, APC, CIC, SDHC, BRAF, NUMA1, EXT2, HRAS, BCL11B, MAGI1, RNF123, NLRP1, ASXL1, ADAMTS20, TAF1L, XPC, DDB2 and ETS1 as mutated genes. The current study could not draw any new conclusions about the relationship between VS-related hearing loss and gene mutations; however, it did reveal that NF2 was the most frequently mutated gene in small sporadic VS.

6.
Auris Nasus Larynx ; 50(1): 165-168, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34986973

RESUMO

Coronavirus disease 2019 (COVID-19) occasionally causes acute laryngitis, requiring emergency treatment. Understanding the characteristic laryngeal findings can help diagnose COVID-19 earlier, prevent worsening infection, and properly manage airway obstruction. Herein, we report the case of a 44-year-old male with acute epiglottitis likely caused by COVID-19. On presentation, chest computed tomography (CT) showed no signs of pneumonia. However, the larynx had extensive necrotic-like erosive lesions resembling those of tuberculous laryngitis. COVID-19 was diagnosed by reverse-transcription polymerase chain reaction, and secondary bacterial superinfections were suspected after blood testing. The symptoms improved after administration of antibiotics (sulbactam sodium/ampicillin sodium), steroids (dexamethasone), and favipiravir. The patient developed a high fever on the sixth day of hospitalization, and pneumonia was identified on CT. Various culture tests, including tuberculosis, were negative. Thus, remdesivir was administered for COVID-19-induced pneumonia. The patient gradually recovered, was transferred to another hospital, and was discharged on the 35th day of hospitalization. Six previous case reports of COVID-19-induced acute epiglottitis suggested that acute epiglottitis preceded the onset of pneumonia. The laryngeal findings from this report may be useful for diagnosing COVID-19 that does not cause pneumonia and for bringing attention to pneumonia after a COVID-19 diagnosis.


Assuntos
COVID-19 , Epiglotite , Laringite , Pneumonia , Masculino , Humanos , Adulto , Epiglotite/diagnóstico , Epiglotite/tratamento farmacológico , COVID-19/complicações , COVID-19/diagnóstico , Laringite/diagnóstico , Teste para COVID-19 , Doença Aguda
7.
Acta Otolaryngol ; 142(7-8): 568-574, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35984435

RESUMO

BACKGROUND: Delayed endolymphatic hydrops (DEH) is an inner ear disease that causes recurrent vertigo in the ipsilateral ear or fluctuating hearing in the contralateral ear due to endolymphatic hydrops secondary to preceding deafness. There are few reports of large, multicentre studies investigating the clinical-epidemiological characteristics of DEH. OBJECTIVE: This study aimed to clarify the characteristics of DEH in Japan. METHODS: Clinical data on 662 patients with DEH were analysed by nationwide, multicentre surveys conducted by the Peripheral Vestibular Disorders Research Group of Japan. RESULTS: The proportion of ipsilateral DEH (IDEH) was slightly higher than that of contralateral DEH (CDEH) at 55.4%. The time delay between onset of precedent deafness and onset of DEH was significantly longer for CDEH than for IDEH. The most common cause of precedent deafness was a disease of unknown cause with onset in early childhood (33.1%). Epidemiological characteristics were not significantly different between CDEH with and without vertigo. CONCLUSION: DEH appearing to be caused by viral labyrinthitis has a high rate of onset within 40 years of precedent deafness. Clinical and epidemiological characteristics of IDEH, CDEH with vertigo, and CDEH without vertigo were very similar. SIGNIFICANCE: The clinical-epidemiological characteristics of DEH in Japan were clarified.


Assuntos
Surdez , Hidropisia Endolinfática , Labirintite , Pré-Escolar , Surdez/complicações , Surdez/epidemiologia , Hidropisia Endolinfática/complicações , Hidropisia Endolinfática/epidemiologia , Humanos , Japão/epidemiologia , Vertigem/epidemiologia , Vertigem/etiologia
9.
Microbiol Resour Announc ; 11(3): e0110621, 2022 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-35254113

RESUMO

The genome sequence of Bacillus cereus strain HT18, isolated from forest soil, was 5,333,415 bp long. The genome included 5,825 putative coding sequences and 35.2% GC content; the strain had 5 plasmids. Average nucleotide identity based on BLAST+ (ANIb) and digital DNA-DNA hybridization (dDDH) results showed that HT18 was 98.78% and 90.70% homologous, respectively, to B. cereus ATCC 14579T.

10.
Acta Otolaryngol ; 142(2): 202-205, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35112650

RESUMO

Background: Malignant neoplasms (MNs) in the head and neck are occasionally hidden in deep neck infections (DNIs) that require emergency treatment, which potentially leads to delayed diagnosis of MNs.Objectives: This study aimed to identify predictive factors that can prevent delays in diagnosing MNs in patients with DNIs.Methods: We retrospectively analysed data from 83 patients admitted to our hospital who were diagnosed with DNIs.Results: Four patients (4.8%) had DNIs veiling MNs in the head and neck. Statistical analyses revealed a significant association (p = .0481) of platelet to albumin ratio (PAR; ≥ 98.9 × 103) with hidden MNs in DNIs. Furthermore, concomitant cervical lymphadenopathy, especially multiple lymphadenopathies and excluding abscesses, was higher in patients with DNIs veiling MNs (p = .0142 and p = .0023, respectively).Conclusions and Significance: The PAR, which can be easily measured and readily detected, was a potential predictive factor. Moreover, performing fine-needle aspiration for lymphadenopathies could help diagnose hidden MNs in DNIs.


Assuntos
Pescoço , Neoplasias , Cabeça , Hospitalização , Humanos , Pescoço/patologia , Neoplasias/patologia , Estudos Retrospectivos
11.
Acta Otolaryngol ; 142(1): 13-18, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34923899

RESUMO

BACKGROUND: In cholesteatoma, the prognosis of tympanoplasty has been well discussed in terms of hearing outcomes and residual or recurrent lesions. Postoperative dizziness and vertigo are major complications of tympanoplasty; however, few reports are available. AIMS/OBJECTIVES: We investigated each condition of cholesteatoma postoperative vestibular risk using the STAM system and staging published by EAONO/JOS, as well as findings on bony destruction. MATERIAL AND METHODS: From April 2010 to March 2021, 156 patients (166 ears) with cholesteatoma who underwent primary microscopic tympanoplasty at our hospital were registered. Subjective vestibular symptoms were recorded the day after surgery. RESULTS: Postoperative vestibular symptoms were observed in 13.9% of subjects. All of them were stage II and had both attic and mastoid lesions. Attic (p < .05) and mastoid (p < .01) lesions were risk factors. Multivariate analysis showed that significant differences were found in past histories of vestibular symptoms (p < .05) and exposure of the dura mater (p < .01). CONCLUSIONS AND SIGNIFICANCE: In the exposed dura group, the length of the prominence of the lateral semicircular canal to the middle cranial fossa dura was significantly shorter than that of the non-exposed group (p < .01). Narrow working space and downward operation may increase vestibular risk.


Assuntos
Colesteatoma da Orelha Média/cirurgia , Complicações Pós-Operatórias/etiologia , Timpanoplastia/métodos , Doenças Vestibulares/etiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
13.
Otol Neurotol ; 42(9): e1286-e1292, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34528923

RESUMO

OBJECTIVES: Vibrant Soundbridge (VSB) was developed for treatment of hearing loss, but clinical outcomes vary and prognostic factors predicting the success of the treatment remain unknown. We examined clinical outcomes of VSB for conductive or mixed hearing loss, prognostic factors by analyzing prediction models, and cut-off values to predict the outcomes. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care hospital. PATIENTS: Thirty patients who underwent VSB surgery from January 2017 to December 2019 at our hospital. INTERVENTION: Audiological tests were performed prior to and 3 months after surgery; patients completed questionnaires 3 months after surgery. MAIN OUTCOME MEASURES: We used a multiregression and the random forest algorithm for predictions. Mean absolute errors and coefficient of determinations were calculated to estimate prediction accuracies. Coefficient values in the multiregression model and the importance of features in the random forest model were calculated to clarify prognostic factors. Receiver operation characteristic curves were plotted. RESULTS: All audiological outcomes improved after surgery. The random forest model (mean absolute error: 0.06) recorded more accuracy than the multiregression model (mean absolute error: 0.12). Speech discrimination score in a silent context in patients with hearing aids was the most influential factor (coefficient value: 0.51, featured value: 0.71). The candidate cut-off value was 36% (sensitivity: 89%, specificity: 75%). CONCLUSIONS: VSB is an effective treatment for conductive or mixed hearing loss. Machine learning demonstrated more precise predictions, and speech discrimination scores in a silent context in patients with hearing aids were the most important factor in predicting clinical outcomes.


Assuntos
Auxiliares de Audição , Perda Auditiva Condutiva-Neurossensorial Mista , Prótese Ossicular , Perda Auditiva Condutiva , Humanos , Aprendizado de Máquina , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento
14.
Head Neck ; 43(12): 3810-3819, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34549854

RESUMO

BACKGROUND: The advantage of up-front neck dissection (UFND) followed by chemoradiotherapy (CRT) for hypopharyngeal cancer (HPC) with advanced neck involvement remains controversial. We aimed to determine the indications. METHODS: The data of 41 and 14 patients with stage IVA/B (T1-T3 and ≥N2a) HPC who underwent UFND followed by CRT and received CRT, respectively, were retrospectively analyzed and compared. RESULTS: The 5-year overall survival (OS) and disease-specific survival rates for the UFND and CRT groups were 61% and 52% (p = 0.1019), and 89% and 74% (p = 0.2333), respectively. Moreover, patients aged ≥70 years or those with a pulmonary disease history had a significantly poorer prognosis due to aspiration pneumonia in the UFND group. The 5-year regional control (RC) for the UFND and CRT groups were 92% and 57%, respectively (p = 0.0001). CONCLUSIONS: UFND followed by CRT was feasible with satisfactory RC. To further improve OS, aspiration pneumonia prevention is essential.


Assuntos
Neoplasias de Cabeça e Pescoço , Neoplasias Hipofaríngeas , Quimiorradioterapia , Humanos , Neoplasias Hipofaríngeas/tratamento farmacológico , Esvaziamento Cervical , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço
15.
J Physiol ; 599(19): 4497-4516, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34426971

RESUMO

Excitable cochlear hair cells convert the mechanical energy of sounds into the electrical signals necessary for neurotransmission. The key process is cellular depolarization via K+ entry from K+ -enriched endolymph through hair cells' mechanosensitive channels. Positive 80 mV potential in endolymph accelerates the K+ entry, thereby sensitizing hearing. This potential represents positive extracellular potential within the epithelial-like stria vascularis; the latter potential stems from K+ equilibrium potential (EK ) across the strial membrane. Extra- and intracellular [K+ ] determining EK are likely maintained by continuous unidirectional circulation of K+ through a putative K+ transport pathway containing hair cells and stria. Whether and how the non-excitable tissue stria vascularis responds to acoustic stimuli remains unclear. Therefore, we analysed a cochlear portion for the best frequency, 1 kHz, by theoretical and experimental approaches. We have previously developed a computational model that integrates ion channels and transporters in the stria and hair cells into a circuit and described a circulation current composed of K+ . Here, in this model, mimicking of hair cells' K+ flow induced by a 1 kHz sound modulated the circulation current and affected the strial ion transport mechanisms; the latter effect resulted in monotonically decreasing potential and increasing [K+ ] in the extracellular strial compartment. Similar results were obtained when the stria in acoustically stimulated animals was examined using microelectrodes detecting the potential and [K+ ]. Measured potential dynamics mirrored the EK change. Collectively, because stria vascularis is electrically coupled to hair cells by the circulation current in vivo too, the strial electrochemical properties respond to sounds. KEY POINTS: A highly positive potential of +80 mV in K+ -enriched endolymph in the mammalian cochlea accelerates sound-induced K+ entry into excitable sensory hair cells, a process that triggers hearing. This unique endolymphatic potential represents an EK -based battery for a non-excitable epithelial-like tissue, the stria vascularis. To examine whether and how the stria vascularis responds to sounds, we used our computational model, in which strial channels and transporters are serially connected to those hair cells in a closed-loop circuit, and found that mimicking hair cell excitation by acoustic stimuli resulted in increased extracellular [K+ ] and decreased the battery's potential within the stria. This observation was overall verified by electrophysiological experiments using live guinea pigs. The sensitivity of electrochemical properties of the stria to sounds indicates that this tissue is electrically coupled to hair cells by a radial ionic flow called a circulation current.


Assuntos
Potássio , Estria Vascular , Animais , Cóclea , Endolinfa , Cobaias , Células Ciliadas Auditivas
16.
Anticancer Drugs ; 32(1): 95-101, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32976215

RESUMO

Immunotherapy has been shown to prolong survival in recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN) in front-line use; however, subsequent systemic therapy has not been optimized. This study aimed to evaluate the safety and efficacy of cetuximab-containing chemotherapy after immunotherapy. We retrospectively analyzed patients with recurrent or metastatic SCCHN who underwent cetuximab-containing regimens after progression on immunotherapy. Of the 22 patients who met the inclusion criteria, 21 received paclitaxel and cetuximab, and 1 carboplatin and fluorouracil and cetuximab after immunotherapy. Nine patients achieved a partial response, 10 patients had stable disease as their best response on cetuximab-containing chemotherapy, yielding an overall response rate and disease control rate of 40.9 and 86.4%, respectively. The median progression-free survival was 5.2 months, and the median overall survival was 14.5 months. Ten patients developed grade 3-4 adverse events, including neutropenia (31.8%), acneiform rash (9.1%), anemia (4.5%), hypertransaminasemia (4.5%) and stomatitis (4.5%). The most frequent cetuximab-related toxicities across all grades were skin reactions (77.3%), hypomagnesemia (40.9%), stomatitis (27.3%), paronychia (13.6%) and keratitis (4.5%). There was no treatment-related death. Taken together, cetuximab-containing chemotherapy was effective and feasible even after immunotherapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Inibidores de Checkpoint Imunológico/uso terapêutico , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Adulto , Idoso , Carboplatina/administração & dosagem , Cetuximab/administração & dosagem , Cisplatino/administração & dosagem , Feminino , Fluoruracila/administração & dosagem , Seguimentos , Neoplasias de Cabeça e Pescoço/imunologia , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem , Prognóstico , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço/imunologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Taxa de Sobrevida
17.
J Surg Case Rep ; 2020(9): rjaa288, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32934788

RESUMO

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome has been proposed to describe a clinicoradiological entity manifesting in the joints, skin and bones. We describe a patient with SAPHO syndrome for whom bilateral tonsillectomy was effective for the treatment of arthralgia, which was quantified using multiple pain scales.

18.
Microbiol Resour Announc ; 9(36)2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32883798

RESUMO

Enterobacter kobei M4-VN, isolated from potatoes with soft rot disease in Vietnam, contains a total of 4,754,309 bp with 4,424 predicted coding sequences and a G+C content of 55.1%.

19.
Acta Otolaryngol ; 140(9): 723-727, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32700983

RESUMO

BACKGROUND: Furosemide-loading cervical vestibular-evoked myogenic potential (FVEMP), in which vestibular function is improved via diuretics-induced dehydration, can be used to estimate the presence of endolymphatic hydrops, one characteristic of Menière's disease. Inner ear magnetic resonance imaging (MRI) can also reveal endolymphatic hydrops.Aims/Objective: This study aimed to compare and confirm the usefulness of these two examination methods for the diagnosis of Menière's disease. METHODS: Twenty patients with definite unilateral Menière's disease were included. All subjects underwent both, FVEMP and inner ear MRI examinations. The results were then compared statistically between the affected and contralateral ears and among the methods. RESULTS: FVEMP and inner ear MRI of the cochlea, saccules, and utricles yielded positive results indicative of endolymphatic hydrops in 55.0%, 60.0%, 45.0%, and 45.0% of cases, respectively. The results of FVEMP were more consistent with those of the cochlea (κ = 0.8) than with those of the saccules or utricles by inner ear MRI (κ = 0.6). CONCLUSIONS: FVEMP appears to be a good and minimally invasive option for evaluating endolymphatic hydrops. However, the combination of FVEMP and inner ear MRI may yield even more accurate evaluations of endolymphatic hydrops.


Assuntos
Hidropisia Endolinfática/diagnóstico por imagem , Hidropisia Endolinfática/fisiopatologia , Imageamento por Ressonância Magnética , Doença de Meniere/diagnóstico , Potenciais Evocados Miogênicos Vestibulares , Adulto , Idoso , Meios de Contraste/administração & dosagem , Furosemida/administração & dosagem , Gadolínio/administração & dosagem , Humanos , Doença de Meniere/diagnóstico por imagem , Pessoa de Meia-Idade , Estudos Retrospectivos
20.
Microb Cell Fact ; 19(1): 126, 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513169

RESUMO

BACKGROUND: Thermostable enzymes are commonly produced in mesophilic hosts for research and bioengineering purposes. However, these hosts do not overexpress the active forms of some biologically functional thermoenzymes. Therefore, an efficient thermophilic expression system is needed. Thermus thermophilus contains an easily manipulable genome and is therefore among the best candidate microbes for a "hot" expression system. We previously identified a strong and inducible promoter that was active in T. thermophilus under supersaturated silica conditions. Here, we report a new heterologous gene expression system based on a silica-inducible promoter in T. thermophilus. RESULTS: A Thermus sp. A4 gene encoding thermostable ß-galactosidase was cloned as a reporter gene into the expression vector pSix1, which contains a selection marker that confers thermostable resistance to hygromycin and a 600 bp DNA region containing a putative silica-inducible promoter. ß-galactosidase activity was 11-fold higher in the presence than in the absence of 10 mM silicic acid. SDS-PAGE revealed a prominent band corresponding to 73 kDa of ß-galactosidase, and this enzyme was expressed as an active and soluble protein (yield: 27 mg/L) in Thermus but as an inclusion body in Escherichia coli. Truncation of the putative silica-inducible promoter region in Thermus expression vector improved the yield of the target protein, possibly by avoiding plasmid instability due to homologous recombination. Finally, we developed an expression vector containing the pSix1 backbone and a 100 bp DNA region corresponding to the silica-inducible promoter. We used this vector to successfully express the active form of glutamate dehydrogenase from Pyrobaculum islandicum (PisGDH) without additional treatment (yield: 9.5 mg/L), whereas the expression of active PisGDH in E. coli required heat treatment. CONCLUSION: We successfully expressed the thermostable ß-galactosidase and PisGDH in T. thermophilus as active and soluble forms and achieved with our system the highest known protein expression levels in this species. These thermoenzymes were expressed in active and soluble forms. Our results validate the use of our silica-inducible expression system as a novel strategy for the intracellular overexpression of thermostable proteins.


Assuntos
Proteínas de Bactérias/biossíntese , Vetores Genéticos , Regiões Promotoras Genéticas , Thermus thermophilus/genética , Clonagem Molecular , Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Glutamato Desidrogenase/biossíntese , beta-Galactosidase/biossíntese
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