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1.
Front Microbiol ; 15: 1357794, 2024.
Article in English | MEDLINE | ID: mdl-38646631

ABSTRACT

The anthocyanin compound cyanidin 3-O-glucoside (C3G) is a natural pigment widely used in food and nutraceutical industries. Its microbial synthesis by E. coli is a promising alternative to the traditional extraction methods. However, part of the synthesized C3G accumulates in the cytoplasm, thus potentially causing growth inhibition and product degradation. Therefore, it is necessary to enhance C3G secretion via exploration of native transporters facilitating C3G export. In this study, we report the screening and verification of native multidrug resistance transporters from 40 candidates in E. coli that can improve the extracellular C3G production when using catechin as the substrate. Overexpression of single transporter genes including fsr, yebQ, ynfM, mdlAB, and emrKY were found to increase C3G production by 0.5- to 4.8-fold. Genetic studies indicated that mdlAB and emrKY are vital transporters in the secretion of C3G. Our study reveals a set of new multidrug resistance transporters for the improvement of microbial biosynthesis of C3G and other anthocyanins.

2.
Mol Genet Genomic Med ; 12(2): e2394, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38337154

ABSTRACT

BACKGROUND: Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare, inherited disorder that causes epilepsy, intellectual disorders, and early onset macrocephaly. MLC1 has been identified as a main pathogenic gene. METHODS: Clinical data such as magnetic resonance imaging (MRI), routine blood tests, and physical examinations were collected from proband. Trio whole-exome sequencing (WES) of the family was performed, and all variants with a minor allele frequency (<0.01) in the exon and canonical splicing sites were selected for further pathogenic evaluation. Candidate variants were validated using Sanger sequencing. RESULTS: Here, we report a new homozygous variant identified in two children from the same family in the MLC1 gene [NM_015166.4: c.838_843delinsATTTTA, (p.Ser280_Phe281delinsIleLeu)]. This variant is classified as variant of uncertain significance (VUS) according to the ACMG guidelines. Further experiments demonstrate that the newly identified variant causes a decrease of MLC1 protein levels when expressed in a heterologous expression system. CONCLUSION: Our case expands on this genetic variation and provides new evidence for the clinical diagnosis of MLC1-related MLC.


Subject(s)
Cysts , Hereditary Central Nervous System Demyelinating Diseases , Megalencephaly , Child , Humans , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mutation , Hereditary Central Nervous System Demyelinating Diseases/diagnostic imaging , Hereditary Central Nervous System Demyelinating Diseases/genetics
3.
Appl Environ Microbiol ; 90(3): e0207923, 2024 Mar 20.
Article in English | MEDLINE | ID: mdl-38349148

ABSTRACT

Anthocyanin cyanidin 3-O-glucoside (C3G) is a natural pigment widely used in food and nutraceutical industries. Its microbial synthesis in Escherichia coli is a promising and efficient way toward large-scale production. The current production titer is low partly due to the accumulation of C3G inside the producing microbes; thus, it is important to explore native transporters responsible for anthocyanin secretion. Currently, there has been only one native E. coli transporter identified with C3G-transporting capability, and its overexpression has a very limited effect on the promotion of extracellular C3G production. In this study, we report the identification and verification of an efficient intrinsic C3G efflux transporter MdtH in E. coli through transcriptomic analysis and genetic/biochemical studies. MdtH could bind C3G with high affinity, and its overexpression increased the extracellular C3G biosynthesis in E. coli by 110%. Our study provides a new regulation target for microbial biosynthesis of C3G and other anthocyanins. IMPORTANCE: Cyanidin 3-O-glucoside (C3G) is a natural colorant with health-promoting activities and is, hence, widely used in food, cosmetic, and nutraceutical industries. Its market supply is currently dependent on extraction from plants. As an alternative, C3G can be produced by the microbe Escherichia coli in a green and sustainable way. However, a large portion of this compound is retained inside the cell of E. coli, thus complicating the purification process and limiting the high-level production. We have identified and verified an efficient native transporter named MdtH in E. coli that can export C3G to the cultivation medium. Overexpression of MdtH could improve extracellular C3G production by 110% without modifications of the metabolic pathway genes or enzymes. This study reveals a new regulation target for C3G production in bacteria and provides guidance to the microbial biosynthesis of related compounds.


Subject(s)
Anthocyanins , Escherichia coli , Escherichia coli/genetics , Escherichia coli/metabolism , Anthocyanins/chemistry , Anthocyanins/metabolism , Glucosides/metabolism , Biological Transport
4.
Metab Eng ; 81: 238-248, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38160746

ABSTRACT

Previously, a novel Corynebacterium glutamicum strain for the de novo biosynthesis of tailored poly-γ-glutamic acid (γ-PGA) has been constructed by our group. The strain was based on the γ-PGA synthetase complex, PgsBCA, which is the only polyprotein complex responsible for γ-PGA synthesis in Bacillus spp. In the present study, PgsBCA was reconstituted and overexpressed in C. glutamicum to further enhance γ-PGA synthesis. First, we confirmed that all the components (PgsB, PgsC, and PgsA) of γ-PGA synthetase derived from B. licheniformis are necessary for γ-PGA synthesis, and γ-PGA was detected only when PgsB, PgsC, and PgsA were expressed in combination in C. glutamicum. Next, the expression level of each pgsB, pgsC, and pgsA was tuned in order to explore the effect of expression of each of the γ-PGA synthetase subunits on γ-PGA production. Results showed that increasing the transcription levels of pgsB or pgsC and maintaining a medium-level transcription level of pgsA led to 35.44% and 76.53% increase in γ-PGA yield (γ-PGA yield-to-biomass), respectively. Notably, the expression level of pgsC had the greatest influence (accounting for 68.24%) on γ-PGA synthesis, followed by pgsB. Next, genes encoding for PgsC from four different sources (Bacillus subtilis, Bacillus anthracis, Bacillus methylotrophicus, and Bacillus amyloliquefaciens) were tested in order to identify the influence of PgsC-encoding orthologues on γ-PGA production, but results showed that in all cases the synthesis of γ-PGA was significantly inhibited. Similarly, we also explored the influence of gene orthologues encoding for PgsB on γ-PGA production, and found that the titer increased to 17.14 ± 0.62 g/L from 8.24 ± 0.10 g/L when PgsB derived from B. methylotrophicus replaced PgsB alone in PgsBCA from B. licheniformis. The resulting strain was chosen for further optimization, and we achieved a γ-PGA titer of 38.26 g/L in a 5 L fermentor by optimizing dissolved oxygen level. Subsequently, by supplementing glucose, γ-PGA titer increased to 50.2 g/L at 48 h. To the best of our knowledge, this study achieved the highest titer for de novo production of γ-PGA from glucose, without addition of L-glutamic acid, resulting in a novel strategy for enhancing γ-PGA production.


Subject(s)
Corynebacterium glutamicum , Fermentation , Corynebacterium glutamicum/genetics , Corynebacterium glutamicum/metabolism , Glutamic Acid , Polyglutamic Acid/genetics , Ligases/metabolism , Glucose/metabolism
5.
J Fungi (Basel) ; 9(10)2023 Oct 19.
Article in English | MEDLINE | ID: mdl-37888283

ABSTRACT

Pichia pastoris is the most widely used microorganism for the production of secreted industrial proteins and therapeutic proteins. Recently, this yeast has been repurposed as a cell factory for the production of chemicals and natural products. In this review, the general physiological properties of P. pastoris are summarized and the readily available genetic tools and elements are described, including strains, expression vectors, promoters, gene editing technology mediated by clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9, and adaptive laboratory evolution. Moreover, the recent achievements in P. pastoris-based biosynthesis of proteins, natural products, and other compounds are highlighted. The existing issues and possible solutions are also discussed for the construction of efficient P. pastoris cell factories.

6.
J Agric Food Chem ; 71(13): 5293-5301, 2023 Apr 05.
Article in English | MEDLINE | ID: mdl-36967580

ABSTRACT

Glycine-rich flexible peptide linkers have been widely adopted in fusion protein engineering; however, they can hardly be cleaved for the separation of fusion partners unless specific protease recognition sites are introduced. Herein, we report the use of the peptidoglycan-targeting staphylolytic enzyme lysostaphin to directly digest the glycine-rich flexible linkers of various lengths including oligoglycine linkers and (G4S)x linkers, without the incorporation of extra amino acids. Using His-MBP-linker-LbCpf1 as a model substrate, we show that both types of linkers could be digested by lysostaphin, and the digestion efficiency improved with increasing linker length. The enzyme LbCpf1 retained full activity after tag removal. We further demonstrated that the proteolytic activity of lysostaphin could be well maintained under different environmental conditions and in the presence of a series of chemical reagents at various concentrations that are frequently used in protein purification and stabilization. In addition, such a digestion strategy could also be applied to remove the SUMO domain linked to LwCas13a via an octaglycine linker. This study extends the applications of lysostaphin beyond an antimicrobial reagent and demonstrates its potential as a novel, efficient, and robust protease for protein engineering.


Subject(s)
Lysostaphin , Peptide Hydrolases , Lysostaphin/chemistry , Lysostaphin/metabolism , Peptidoglycan/chemistry , Peptidoglycan/metabolism , Glycine , Cell Wall/metabolism
7.
Appl Microbiol Biotechnol ; 107(5-6): 1663-1672, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36719434

ABSTRACT

O-Methylation catalyzed by O-methyltransferases (OMTs) is an important modification of flavonoids for improving the transport efficiency across membranes and metabolic stability in mammalian cells. Chrysoeriol, also known as 3'-O-methylated luteolin, is a methylated flavonoid compound with health-promoting activities. The generation of chrysoeriol from luteolin can be catalyzed by a rice-derived 3'-OMT named ROMT-9, which has a high regiospecificity and activity toward flavonoids in vitro. Herein, we explored the potential of ROMT-9 for in vivo biosynthesis of chrysoeriol in Escherichia coli and adopted semi-rational enzyme engineering guided by homology modeling and molecular docking to improve the bio-production. Two positive variants including L34Q and W284A were obtained which promoted chrysoeriol formation to more than 85 mg/L from 200 mg/L of luteolin in 24 h compared with a titer of 55 mg/L for the strain expressing the native enzyme. Further biochemical analysis confirmed that such improvement in production stemmed from a higher enzyme expression level for the L34Q variant and higher efficiency in substrate binding and catalysis for the W284A variant. This study provides some insights into the engineering of other flavonoid OMTs and will facilitate high-level biosynthesis of methylated flavonoids in engineered microorganisms. KEY POINTS: • Biosynthesis of chrysoeriol from luteolin in E. coli using ROMT-9 • Engineering of ROMT-9 for better bio-production • ROMT-9 variants promote production via better expression or better catalysis.


Subject(s)
Flavonoids , Methyltransferases , Animals , Flavonoids/metabolism , Methyltransferases/metabolism , Escherichia coli/metabolism , Luteolin/metabolism , Molecular Docking Simulation , Mammals/metabolism
8.
Curr Opin Biotechnol ; 79: 102870, 2023 02.
Article in English | MEDLINE | ID: mdl-36549106

ABSTRACT

Corynebacterium glutamicum, a natural glutamate-producing bacterium adopted for industrial production of amino acids, has been extensively explored recently for high-level biosynthesis of amino acid derivatives, bulk chemicals such as organic acids and short-chain alcohols, aromatics, and natural products, including polyphenols and terpenoids. Here, we review the recent advances with a focus on biosystem design principles, metabolic characterization and modeling, omics analysis, utilization of nonmodel feedstock, emerging CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) tools for Corynebacterium strain engineering, biosensors, and novel strains of C. glutamicum. Future research directions for developing C. glutamicum cell factories are also discussed.


Subject(s)
Biological Products , Corynebacterium glutamicum , Corynebacterium glutamicum/genetics , Corynebacterium glutamicum/metabolism , Metabolic Engineering , Amino Acids/metabolism , Clustered Regularly Interspaced Short Palindromic Repeats , Biological Products/metabolism
9.
Medicine (Baltimore) ; 102(52): e36675, 2023 Dec 29.
Article in English | MEDLINE | ID: mdl-38206725

ABSTRACT

INTRODUCTION: Cases with early diagnosis of neonatal tuberous sclerosis syndrome (TSC) are relatively seldom seen, and misdiagnosis of intracranial hemorrhage is even more rare. We retrospectively analyzed the clinical data of a case of neonatal tuberous sclerosis with atypical early symptoms and misdiagnosed as more common intracranial hemorrhage of the newborn. PATIENT CONCERNS: The child was female and had no obvious cause of convulsion 12 days after birth. The local hospital was initially diagnosed as "neonatal intracranial hemorrhage, congenital heart disease," and still had convulsions after 5 days of treatment, so it was transferred to neonatal intensive care unit of our hospital. DIAGNOSIS: After admission, cardiac color ultrasound, magnetic resonance imaging, and electroencephalogram were performed, and TSC was diagnosed in combination with clinical symptoms. However, no known pathogenic mutations such as TSC1 and TSC2 were detected by peripheral blood whole exon sequencing. INTERVENTION: After a clear diagnosis, sirolimus, and vigabatrin were given. But there were still convulsions. Topiramate, valproic acid, and oxcarbazepine were successively added to the outpatient department for antiepileptic treatment, and vigabatrin gradually decreased. OUTCOME: Up to now, although the seizures have decreased, they have not been completely controlled. CONCLUSIONS: The TSC of neonatal tuberous sclerosis is different from that of older children. It is usually characterized by respiratory distress and arrhythmia, and may be accompanied by convulsions, but the activity between attacks is normal. However, neonatal intracranial hemorrhage can be caused by premature delivery, birth injury, hypoxia, etc. Its characteristics are acute onset, severe illness, and rapid progression. Consequently, the diagnosis of these 2 diseases should not only be based on medical imaging, but also be combined with their clinical characteristics. When the imaging features are inconsistent with the clinical diagnosis, a comprehensive evaluation should be made again. The timing and pattern of onset of neonatal convulsions can help in differential diagnosis. If there is cardiac rhabdomyoma, subependymal or cortical nodule, skin low melanoma, etc, the possibility of neonatal TSC should be considered, and the diagnosis should be made according to its diagnostic criteria to avoid or reduce misdiagnosis.


Subject(s)
Fetal Diseases , Tuberous Sclerosis , Female , Humans , Infant, Newborn , Diagnostic Errors , Fetal Diseases/diagnosis , Hemorrhage/complications , Intracranial Hemorrhages/etiology , Intracranial Hemorrhages/complications , Mutation , Retrospective Studies , Seizures/complications , Tuberous Sclerosis/complications , Tuberous Sclerosis Complex 2 Protein/genetics , Tumor Suppressor Proteins/genetics , Vigabatrin/genetics
10.
Medicine (Baltimore) ; 101(50): e31495, 2022 Dec 16.
Article in English | MEDLINE | ID: mdl-36550836

ABSTRACT

BACKGROUND: previous studies have shown that phenobarbital (PB) is a effective and safe drug in the treatment of benign convulsions with mild gastroenteritis (CwG), but there is a lack of large sample prospective randomized controlled study of different doses. This study was a prospective randomized controlled study on the efficacy and safety of different doses of phenobarbital for CwG. There has been no similar study. METHODS: One hundred twenty CwG cases were included in this study. All of them were hospitalized in the Department of Neurology of Jiangxi Provincial Children's Hospital from January 2019 to August 2021. They were randomly divided into 10 mg/kg single dose group (Group A, n = 60) and 5 mg/kg single dose group (Group B, n = 60). The criteria for judging the efficacy of PB in our study were there was no convulsion in the course of acute gastroenteritis within 2 weeks after using PB. RESULTS: The effective rate was 93.33% in group A and 80.00% in group B. There was significant difference between the 2 groups (P < .05). Drowsiness was the most frequent adverse reaction. 14 cases in group A and 7 cases in group B had drowsiness. There was no significant difference between the 2 groups in the incidence of adverse events such as somnolence, ataxia, abnormal liver function, anemia, abnormal leukocyte, respiratory depression, cognitive impairment, rash, abnormal platelet and abnormal renal function (P > .05). All side reaction were transient. CONCLUSION: it is suggested that PB 10 mg/kg intravenously should be used as soon as possible for CwG, which has high effectiveness and safety.


Subject(s)
Gastroenteritis , Seizures , Child , Humans , Infant , Prospective Studies , Seizures/drug therapy , Seizures/etiology , Gastroenteritis/complications , Gastroenteritis/drug therapy , Gastroenteritis/epidemiology , Phenobarbital/therapeutic use , Incidence
11.
Front Nutr ; 9: 1029324, 2022.
Article in English | MEDLINE | ID: mdl-36337619

ABSTRACT

The oral cavity is a key biocenosis for many distinct microbial communities that interact with both the external environment and internal body systems. The oral microbiota is a vital part of the human microbiome. It has been developed through mutual interactions among the environment, host physiological state, and microbial community composition. Indigenious microbiota of the oral cavity is one of the factors that prevent adhesion and invasion of pathogens on the mucous membrane, i.e., the development of the infectious process and thereby participating in the implementation of one of the mechanisms of local immunity-colonization resistance. The balance between bacterial symbiosis, microbial virulence, and host resistance ensures the integrity of the oral cavity. In this review we have tried to address how nutritional factors influence integrity of the oral indigenous microbiota and its involvement in colonization resistance.

12.
Front Neurol ; 13: 995513, 2022.
Article in English | MEDLINE | ID: mdl-36188413

ABSTRACT

Benign convulsions with mild gastroenteritis (CwG) is characterized by afebrile convulsions accompanied by mild gastroenteritis, and it can be considered after central nervous system infection, hypoglycemia, electrolyte disturbance, and moderate and severe dehydration are excluded. Previous studies have suggested that genetics may be involved in CWG. Herein, we reported a novel de novo variant of SCN8A in a child with CwG. This is the first report that SCN8A may be associated with CwG. Our report may provides evidence for the genetic etiology of CwG and expands the phenotypic and genetic spectrum of SCN8A-related disorders, which previously included severe developmental and epileptic encephalopathy (DEE) phenotype, benign epilepsy phenotype, spectrum of intermediate epilepsies, and patients with cognitive and/or behavioral disturbances without epilepsy. Phenotype of CwG has a good prognosis, and it does not require long-term antiepileptic therapy. Overtreatment should be avoided clinically. However, the conclusion needs to be further defined by long-term follow-up and similar clinical reports. In spite of this, our clinical observation provides possible evidence for future studies on the relationship between SCN8A and CwG.

13.
J Agric Food Chem ; 70(37): 11441-11457, 2022 Sep 21.
Article in English | MEDLINE | ID: mdl-36082619

ABSTRACT

Lysostaphin is a potent bacteriolytic enzyme with endopeptidase activity against the common pathogen Staphylococcus aureus. By digesting the pentaglycine crossbridge in the cell wall peptidoglycan of S. aureus including the methicillin-resistant strains, lysostaphin initiates rapid lysis of planktonic and sessile cells (biofilms) and has great potential for use in agriculture, food industries, and pharmaceutical industries. In the past few decades, there have been tremendous efforts in potentiating lysostaphin for better applications in these fields, including engineering of the enzyme for higher potency and lower immunogenicity with longer-lasting effects, formulation and immobilization of the enzyme for higher stability and better durability, and recombinant expression for low-cost industrial production and in situ biocontrol. These achievements are extensively reviewed in this article focusing on applications in disease control, food preservation, surface decontamination, and pathogen detection. In addition, some basic properties of lysostaphin that have been controversial and only elucidated recently are summarized, including the substrate-binding properties, the number of zinc-binding sites, the substrate range, and the cleavage site in the pentaglycine crossbridge. Resistance to lysostaphin is also highlighted with a focus on various mechanisms. This article is concluded with a discussion on the limitations and future perspectives for the actual applications of lysostaphin.


Subject(s)
Lysostaphin , Staphylococcus aureus , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Bacteriolysis , Lysostaphin/chemistry , Lysostaphin/metabolism , Lysostaphin/pharmacology , Peptidoglycan/chemistry , Peptidoglycan/metabolism , Staphylococcus aureus/metabolism , Zinc/metabolism
14.
Front Neurol ; 13: 863826, 2022.
Article in English | MEDLINE | ID: mdl-35685742

ABSTRACT

Objective: Tuberous sclerosis complex (TSC) is a rare disease with a high risk of epilepsy and cognitive impairment in children. Ketogenic diet (KD) therapy has been consistently reported to be beneficial to TSC patients. In this study, we aimed to investigate the efficacy and safety of KD in the treatment of drug-resistant epilepsy and cognitive impairment in children with TSC. Methods: In this multicenter study, 53 children (33 males and 20 females) with drug-resistant epilepsy or cognitive impairment caused by TSC were retrospectively recruited from 10 hospitals from January 1, 2010, to December 31, 2020. Intention-to-treat analysis was used to evaluate seizure reduction and cognition improvement as outcomes after KD therapy. Results: Of the 53 TSC patients included, 51 failed to be seizure-free with an average of 5.0 (range, 4-6) different anti-seizure medications (ASMs), before KD therapy. Although the other two patients achieved seizure freedom before KD, they still showed psychomotor development delay and electroencephalogram (EEG) abnormalities. At 1, 3, 6, and 12 months after the KD therapy, 51 (100%), 46 (90.2%), 35 (68.6%), and 16 patients (31.4%) remained on the diet therapy, respectively. At these time points, there were 26 (51.0%), 24 (47.1%), 22 (43.1%) and 13 patients (25.5%) having ≥50% reductions in seizure, including 11 (21.6%), 12 (23.5%), 9 (17.6%) and 3 patients (5.9%) achieving seizure freedom. In addition, of 51 patients with psychomotor retardation, 36 (36 of 51, 70.6%) showed cognitive and behavioral improvements. During the KD therapy, no serious side effects occurred in any patient. The most common side effects were gastrointestinal disturbance (20 of 53, 37.7%) and hyperlipidemia (6 of 53, 11.3%). The side effects were gradually relieved after adjustment of the ketogenic ratio and symptomatic treatment. Conclusion: KD is an effective and safe treatment for TSC-related drug-resistant epilepsy and cognitive impairment in children. KD can reduce seizure frequency and may potentially improve cognition and behavior.

15.
Microb Cell Fact ; 21(1): 86, 2022 May 14.
Article in English | MEDLINE | ID: mdl-35568867

ABSTRACT

BACKGROUND: Eriodictyol is a bioactive flavonoid compound that shows potential applications in medicine development and food processing. Microbial synthesis of eriodictyol has been attracting increasing attention due to several benefits. In this study, we employed a GRAS strain Corynebacterium glutamicum as the host to produce eriodictyol directly from tyrosine. RESULTS: We firstly optimized the biosynthetic module of naringenin, the upstream intermediate for eriodictyol production, through screening of different gene orthologues. Next, to improve the level of the precursor malonyl-CoA necessary for naringenin production, we introduced matB and matC from Rhizobium trifolii into C. glutamicum to convert extracellular malonate to intracellular malonyl-CoA. This combinatorial engineering resulted in around 35-fold increase in naringenin production from tyrosine compared to the initial recombinant C. glutamicum. Subsequently, the hpaBC genes from E. coli encoding 4-hydroxyphenylacetate 3-hydroxylase were expressed in C. glutamicum to synthesize eriodictyol from naringenin. Further optimization of the biotransformation process parameters led to the production of 14.10 mg/L eriodictyol. CONCLUSIONS: The biosynthesis of the ortho-hydroxylated flavonoid eriodictyol in C. glutamicum was achieved for the first time via functional expression of E. coli hpaBC, providing a baseline strain for biosynthesis of other complex flavonoids. Our study demonstrates the potential application of C. glutamicum as a host microbe for the biosynthesis of value-added natural compounds from tyrosine.


Subject(s)
Corynebacterium glutamicum , Corynebacterium glutamicum/genetics , Corynebacterium glutamicum/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Flavanones , Flavonoids/metabolism , Malonyl Coenzyme A/metabolism , Metabolic Engineering/methods , Tyrosine/metabolism
16.
Biotechnol Adv ; 55: 107912, 2022.
Article in English | MEDLINE | ID: mdl-35041862

ABSTRACT

Microbial cell surface layers, which mainly include the cell membrane, cell wall, periplasmic space, outer membrane, capsules, S-layers, pili, and flagella, control material exchange between the cell and the extracellular environment, and have great impact on production titers and yields of various bio-products synthesized by microbes. Recent research work has made exciting achievements in metabolic engineering using microbial cell surface components as novel regulation targets without direct modifications of the metabolic pathways of the desired products. This review article will summarize the accomplishments obtained in this emerging field, and will describe various engineering strategies that have been adopted in bacteria and yeasts for the enhancement of mass transfer across the cell surface, improvement of protein expression and folding, modulation of cell size and shape, and re-direction of cellular resources, all of which contribute to the construction of more efficient microbial cell factories toward the synthesis of a variety of bio-products. The existing problems and possible future directions will also be discussed.


Subject(s)
Cell Engineering , Metabolic Engineering , Cell Membrane , Metabolic Networks and Pathways , Yeasts/genetics
17.
Front Oncol ; 11: 669518, 2021.
Article in English | MEDLINE | ID: mdl-34178653

ABSTRACT

In non-small-cell lung carcinoma (NSCLC), aberrant activation of mammalian target of rapamycin (mTOR) contributes to tumorigenesis and cancer progression. PQR620 is a novel and highly-potent mTOR kinase inhibitor. We here tested its potential activity in NSCLC cells. In primary human NSCLC cells and established cell lines (A549 and NCI-H1944), PQR620 inhibited cell growth, proliferation, and cell cycle progression, as well as cell migration and invasion, while inducing significant apoptosis activation. PQR620 disrupted assembles of mTOR complex 1 (mTOR-Raptor) and mTOR complex 2 (mTOR-Rictor-Sin1), and blocked Akt, S6K1, and S6 phosphorylations in NSCLC cells. Restoring Akt-mTOR activation by a constitutively-active Akt1 (S473D) only partially inhibited PQR620-induced cytotoxicity in NSCLC cells. PQR620 was yet cytotoxic in Akt1/2-silenced NSCLC cells, supporting the existence of Akt-mTOR-independent mechanisms. Indeed, PQR620 induced sphingosine kinase 1 (SphK1) inhibition, ceramide production and oxidative stress in primary NSCLC cells. In vivo studies demonstrated that daily oral administration of a single dose of PQR620 potently inhibited primary NSCLC xenograft growth in severe combined immune deficient mice. In PQR620-treated xenograft tissues, Akt-mTOR inactivation, apoptosis induction, SphK1 inhibition and oxidative stress were detected. In conclusion, PQR620 exerted potent anti-NSCLC cell activity via mTOR-dependent and -independent mechanisms.

18.
Cell Death Dis ; 12(4): 365, 2021 04 06.
Article in English | MEDLINE | ID: mdl-33824293

ABSTRACT

Activation of adenosine monophosphate-activated protein kinase (AMPK) is able to produce significant anti-non-small cell lung cancer (NSCLC) cell activity. ASP4132 is an orally active and highly effective AMPK activator. The current study tested its activity against NSCLC cells. In primary NSCLC cells and established cell lines (A549 and NCI-H1944) ASP4132 potently inhibited cell growth, proliferation and cell cycle progression as well as cell migration and invasion. Robust apoptosis activation was detected in ASP4132-treated NSCLC cells. Furthermore, ASP4132 treatment in NSCLC cells induced programmed necrosis, causing mitochondrial p53-cyclophilin D (CyPD)-adenine nucleotide translocase 1 (ANT1) association, mitochondrial depolarization and medium lactate dehydrogenase release. In NSCLC cells ASP4132 activated AMPK signaling, induced AMPKα1-ACC phosphorylation and increased AMPK activity. Furthermore, AMPK downstream events, including mTORC1 inhibition, receptor tyrosine kinases (PDGFRα and EGFR) degradation, Akt inhibition and autophagy induction, were detected in ASP4132-treated NSCLC cells. Importantly, AMPK inactivation by AMPKα1 shRNA, knockout (using CRISPR/Cas9 strategy) or dominant negative mutation (T172A) almost reversed ASP4132-induced anti-NSCLC cell activity. Conversely, a constitutively active AMPKα1 (T172D) mimicked and abolished ASP4132-induced actions in NSCLC cells. In vivo, oral administration of a single dose of ASP4132 largely inhibited NSCLC xenograft growth in SCID mice. AMPK activation, mTORC1 inhibition and EGFR-PDGFRα degradation as well as Akt inhibition and autophagy induction were detected in ASP4132-treated NSCLC xenograft tumor tissues. Together, activation of AMPK by ASP4132 potently inhibits NSCLC cell growth in vitro and in vivo.


Subject(s)
AMP-Activated Protein Kinases/drug effects , Apoptosis/drug effects , Cell Proliferation/drug effects , Protein Kinase Inhibitors/pharmacology , AMP-Activated Protein Kinases/metabolism , Animals , Antineoplastic Agents/pharmacology , Carcinoma, Non-Small-Cell Lung/pathology , Cell Cycle/drug effects , Cell Line, Tumor , Cell Movement/drug effects , Humans , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Mice , Mice, SCID , Signal Transduction/drug effects
19.
Epileptic Disord ; 23(2): 337-345, 2021 Apr 01.
Article in English | MEDLINE | ID: mdl-33772508

ABSTRACT

To determine the efficacy of ketogenic diet (KD) therapy on adrenocorticotropic hormone- (ACTH) or corticosteroid-resistant infantile spasm (IS), and identify relevant associated factors. A prospective controlled study was undertaken at 10 tertiary children's medical centres in mainland China. Participants were non-randomly assigned to KD therapy or control (adjustment of antiepileptic drugs). The primary outcome was the reduction in spasms and remission of hypsarrhythmia at the 16th week, divided into Grade I (spasm-free for at least one week with hypsarrhythmia remission), Grade II (≥50% spasm reduction and/or hypsarrhythmia remission) and Grade III (<50% spasm reduction with hypsarrhythmia). In total, 227 patients were recruited and assigned to the KD (135 patients) and control (92 patients) groups. The efficacy in the KD group was superior to that in the control group (Grade I: 13.4% vs. 10.9%; Grade II: 40.7% vs. 20.7%, p=0.025). Patients with a ketogenic ratio <3:1 had a higher rate of Grade I than those with ketogenic ratio ≥3:1 (66.7% vs. 33.3%, p=0.037). No significant correlation was found between the efficacy of KD and level of serum ketosis, aetiology of IS, or age. The efficacy of KD therapy was superior to adjustment of oral antiepileptic drugs in children with ACTH- or corticosteroid-resistant infantile spasms.


Subject(s)
Diet, Ketogenic , Spasms, Infantile , Adrenal Cortex Hormones/therapeutic use , Adrenocorticotropic Hormone , Anticonvulsants/therapeutic use , Humans , Infant , Prospective Studies , Spasm , Spasms, Infantile/drug therapy , Treatment Outcome
20.
J Agric Food Chem ; 69(10): 3134-3143, 2021 Mar 17.
Article in English | MEDLINE | ID: mdl-33656890

ABSTRACT

Recovery of recombinant proteins from the Escherichia coli cytoplasm depends on cell disruption by mechanical, chemical, and/or enzymatic methods, which usually cause incomplete cell breakage or protein denaturation. Controllable autolytic E. coli strains have been designed to facilitate the purification of recombinant proteins; however, these strains suffer from low recovery yield, slow cell lysis, or extensive strain engineering. Herein, we report an improved, highly efficient programmable autolytic E. coli platform, in which cell lysis is initiated upon the induced expression of T4 lysozyme with N-terminal fusion of a cell-penetrating peptide. Through the engineering of the peptide sequence and copy number, and by incorporating the fusion lytic gene into the E. coli genome, more than 99.97% of cells could be lysed within 30 min of induction regardless of cell age. We further tested the expression and release of a recombinant enzyme lysostaphin (Lst) and demonstrated that 4 h induction of the lytic gene after 3 h of Lst expression resulted in 98.97% cell lysis. Lst obtained from this system had the same yield, yet 1.63-fold higher activity, compared with that obtained from cells lysed by freeze-thawing and sonication. This autolytic platform shows potential for use in large-scale microbial production of proteins and other biopolymers.


Subject(s)
Endopeptidases , Escherichia coli , Autolysis , Endopeptidases/genetics , Escherichia coli/genetics , Humans , Recombinant Fusion Proteins , Recombinant Proteins/genetics
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