RESUMO
Due to their ability to produce isomaltulose, sucrose isomerases are enzymes that have caught the attention of researchers and entrepreneurs since the 1950s. However, their low activity and stability at temperatures above 40 °C have been a bottleneck for their industrial application. Specifically, the instability of these enzymes has been a challenge when it comes to their use for the synthesis and manufacturing of chemicals on a practical scale. This is because industrial processes often require biocatalysts that can withstand harsh reaction conditions, like high temperatures. Since the 1980s, there have been significant advancements in the thermal stabilization engineering of enzymes. Based on the literature from the past few decades and the latest achievements in protein engineering, this article systematically describes the strategies used to enhance the thermal stability of sucrose isomerases. Additionally, from a theoretical perspective, we discuss other potential mechanisms that could be used for this purpose.
Assuntos
Isomerases , Engenharia de Proteínas , Temperatura , Sacarose , Estabilidade EnzimáticaRESUMO
Chloroplast biotechnology has emerged as a promissory platform for the development of modified plants to express products aimed mainly at the pharmaceutical, agricultural, and energy industries. This technology's high value is due to its high capacity for the mass production of proteins. Moreover, the interest in chloroplasts has increased because of the possibility of expressing multiple genes in a single transformation event without the risk of epigenetic effects. Although this technology solves several problems caused by nuclear genetic engineering, such as turning plants into safe bio-factories, some issues must still be addressed in relation to the optimization of regulatory regions for efficient gene expression, cereal transformation, gene expression in non-green tissues, and low transformation efficiency. In this article, we provide information on the transformation of plastids and discuss the most recent achievements in chloroplast bioengineering and its impact on the biopharmaceutical and agricultural industries; we also discuss new tools that can be used to solve current challenges for their successful establishment in recalcitrant crops such as monocots.
Assuntos
Transformação Genética , Produtos Biológicos , Cloroplastos , Produtos Agrícolas , Biotecnologia , Proteínas Recombinantes/biossíntese , Plantas Geneticamente ModificadasRESUMO
Lactoferrin is an iron binding glycoprotein with multiple roles in the body. Its participation in apoptotic processes in cancer cells, its ability to modulate various reactions of the immune system, and its activity against a broad spectrum of pathogenic microorganisms, including respiratory viruses, have made it a protein of broad interest in pharmaceutical and food research and industry. In this review, we have focused on describing the most important functions of lactoferrin and the possible mechanisms of action that lead to its function.
Assuntos
Anti-Infecciosos/metabolismo , Antineoplásicos/metabolismo , Fatores Imunológicos/metabolismo , Lactoferrina/metabolismo , Animais , HumanosRESUMO
BACKGROUND: Maize is one of the most important crops worldwide and has been a target of nuclear-based transformation biotechnology to improve it and satisfy the food demand of the ever-growing global population. However, the maize plastid transformation has not been accomplished due to the recalcitrant condition of the crop. RESULTS: In this study, we constructed two different vectors with homologous recombination sequences from maize (Zea mays var. LPC13) and grass (Bouteloua gracilis var. ex Steud) (pZmcpGFP and pBgcpGFP, respectively). Both vectors were designed to integrate into rrn23S/rrn16S from an inverted repeat region in the chloroplast genome. Moreover, the vector had the mgfp5 gene driven by Prrn, a leader sequence of the atpB gene and a terminator sequence from the rbcL gene. Also, constructs have an hph gene as a selection marker gene driven by Prrn, a leader sequence from rbcL gene and a terminator sequence from the rbcL gene. Explants of maize, tobacco and Escherichia coli cells were transformed with both vectors to evaluate the transitory expressionan exhibition of green and red fluorescent light under epifluorescence microscopy. These results showed that both vectors were expressed; the reporter gene in all three organisms confirmed the capacity of the vectors to express genes in the cell compartments. CONCLUSIONS: This paper is the first report of transient expression of GFP in maize embryos and offers new information for genetically improving recalcitrant crops; it also opens new possibilities for the improvement in maize chloroplast transformation with these vectors.
Assuntos
Nicotiana/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Zea mays/genética , Proteínas de Fluorescência Verde/metabolismo , Transformação Genética , Biotecnologia , Reação em Cadeia da Polimerase , Plantas Geneticamente Modificadas , Plastídeos/genética , Proteínas de Fluorescência Verde/genética , Escherichia coli , Genoma de CloroplastosRESUMO
Breast cancer is the most frequently diagnosed cancer among women worldwide. Here, recombinant human lactoferrin (rhLf) expressed in Pichia pastoris was tested for its potential cytotoxic activity on a panel of six human breast cancer cell lines. The rhLf cytotoxic effect was determined via a live-cell HTS imaging assay. Also, confocal microscopy and flow cytometry protocols were employed to investigate the rhLf mode of action. The rhLf revealed an effective CC50 of 91.4 and 109.46 µg/ml on non-metastatic and metastatic MDA-MB-231 cells, with favorable selective cytotoxicity index values, 11.68 and 13.99, respectively. Moreover, rhLf displayed satisfactory SCI values on four additional cell lines, MDA-MB-468, HCC70, MCF-7 and T-47D (1.55-3.34). Also, rhLf provoked plasma membrane blebbing, chromatin condensation and cell shrinkage in MDA-MB-231 cells, being all three apoptosis-related morphological changes. Also, rhLf was able to shrink the microfilaments, forming a punctuated cytoplasmic pattern in both the MDA-MB-231 and Hs-27 cells, as visualized in confocal photomicrographs. Moreover, performing flow cytometric analysis, rhLf provoked significant phosphatidylserine externalization, cell cycle arrest in the S phase and apoptosis-induced DNA fragmentation in MDA-MB-231 cells. Hence, rhLf possesses selective cytotoxicity on breast cancer cells. Also, rhLf caused apoptosis-associated morphologic changes, disruption of F-actin cytoskeleton organization, phosphatidylserine externalization, DNA fragmentation, and arrest of the cell cycle progression on triple-negative breast cancer MDA-MB-231 cells. Overall results suggest that rhLf is using the apoptosis pathway as its mechanism to inflict cell death. Findings warranty further evaluation of rhLf as a potential anti-breast cancer drug option.
Assuntos
Citoesqueleto de Actina/efeitos dos fármacos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Lactoferrina/farmacologia , Neoplasias de Mama Triplo Negativas/patologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Lactoferrina/genética , Lactoferrina/isolamento & purificação , Lactoferrina/metabolismo , Fosfatidilserinas/metabolismo , Pichia/genética , Pichia/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologiaRESUMO
In this study, bovine lactoferrin (bLf), an iron-binding glycoprotein considered an important nutraceutical protein because of its several properties, was expressed in Pichia pastoris KM71-H under AOX1 promoter control, using pJ902 as the recombinant plasmid. Dot blotting analysis revealed the expression of recombinant bovine lactoferrin (rbLf) in Pichia pastoris. After Bach fermentation and purification by molecular exclusion, we obtained an expression yield of 3.5 g/L of rbLf. rbLf and predominantly pepsin-digested rbLf (rbLfcin) demonstrated antibacterial activity against Escherichia coli (E. coli) BL21DE3, Staphylococcus aureus (S. aureus) FRI137, and, in a smaller percentage, Pseudomonas aeruginosa (Ps. Aeruginosa) ATCC 27833. The successful expression and characterization of functional rbLf expressed in Pichia pastoris opens a prospect for the development of natural antimicrobial agents produced recombinantly.
Assuntos
Antibacterianos/farmacologia , Lactoferrina/metabolismo , Pichia/metabolismo , Animais , Bovinos , Fermentação , Microbiologia Industrial/métodos , Lactoferrina/genética , Lactoferrina/farmacologia , Pichia/genética , Pichia/crescimento & desenvolvimento , Regiões Promotoras Genéticas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
Lactoferrin is a member of the transferrin family of iron-binding proteins with a number of properties, including antibacterial activity against a broad spectrum of Gram-negative and Gram-positive bacteria. bovine lactoferrin cDNA was isolated, cloned and expressed as a fusion protein. The amino acid sequence of the fusion was analyzed and compared with other species. Crystallographic data were used to compare structural differences between bovine and human lactoferrin in 3-D models. A thioredoxin fusion protein was expressed and shown to have a different molecular weight compared with native bLf. After purification using Ni-NTA, the yield of recombinant bovine lactoferrin was 15.3 mg/l with a purity of 90.3 %. Recombinant bLf and pepsin-digested rbLf peptides demonstrated antibacterial activity of 79.8 and 86.9 %, respectively. The successful expression of functional, active and intact rbLf allows us to study the biochemical interactions of antimicrobial proteins and peptides and will facilitate their study as immunomodulators.
Assuntos
Antibacterianos/biossíntese , Escherichia coli/efeitos dos fármacos , Lactoferrina/biossíntese , Sequência de Aminoácidos , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Bovinos , Clonagem Molecular , Expressão Gênica , Lactoferrina/química , Lactoferrina/farmacologia , Testes de Sensibilidade Microbiana , Modelos Moleculares , Dados de Sequência Molecular , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologia , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Homologia Estrutural de ProteínaRESUMO
BACKGROUND: Lactoferrin (Lf) is an 80kDa iron-binding glycoprotein of the transferrin family. It is abundant in milk and in most biological fluids and is a cell-secreted molecule that bridges innate and adaptive immune function in mammals. Its protective effects range from anticancer, anti-inflammatory and immune modulator activities to antimicrobial activities against a large number of microorganisms. This wide range of activities is made possible by mechanisms of action involving not only the capacity of Lf to bind iron but also interactions of Lf with molecular and cellular components of both hosts and pathogens. SCOPE OF REVIEW: This review summarizes the activities of Lf, its regulation and potential applications. MAJOR CONCLUSIONS: The extensive uses of Lf in the treatment of various infectious diseases in animals and humans has been the driving force in Lf research however, a lot of work is required to obtain a better understanding of its activity. GENERAL SIGNIFICANCE: The large potential applications of Lf have led scientists to develop this nutraceutical protein for use in feed, food and pharmaceutical applications. This article is part of a Special Issue entitled Molecular Mechanisms of Iron Transport and Disorders.
Assuntos
Ferro/metabolismo , Lactoferrina , Imunidade Adaptativa , Animais , Antibacterianos , Anti-Inflamatórios , Antifúngicos , Antivirais , Sequência de Bases , Lactoferrina/química , Lactoferrina/metabolismo , Leite/química , Estrutura Terciária de ProteínaRESUMO
Lactoferrin (LF) is an 80 kDa iron-binding glycoprotein of the transferrin family that is expressed in most biological fluids and is a major component of the mammalian innate immune system. Its protective effects range from direct antimicrobial activities against a large panel of microorganisms, including bacteria, viruses, fungi and parasites, to anti-inflammatory and anticancer activities. These extensive activities are made possible by mechanisms of action utilising not only the capacity of LF to bind iron but also interactions of LF with molecular and cellular components of both host and pathogens. This review summarises the putative antimicrobial mechanisms, clinical applications and heterologous expression models for LF.