RESUMEN
Drought stress is threatening the growth and productivity of many economical crops. Therefore, it is necessary to establish innovative and efficient approaches for improving crop growth and productivity. Here we investigated the potentials of the cell-free extract of Actinobacteria (Ac) isolated from a semi-arid habitat (Al-Jouf region, Saudi Arabia) to recover the reduction in maize growth and improve the physiological stress tolerance induced by drought. Three Ac isolates were screened for production of secondary metabolites, antioxidant and antimicrobial activities. The isolate Ac3 revealed the highest levels of flavonoids, antioxidant and antimicrobial activities in addition to having abilities to produce siderophores and phytohormones. Based on seed germination experiment, the selected bioactive fraction of Ac3 cell-free extract (F2.7, containing mainly isoquercetin), increased the growth and photosynthesis rate under drought stress. Moreover, F2.7 application significantly alleviated drought stress-induced increases in H2O2, lipid peroxidation (MDA) and protein oxidation (protein carbonyls). It also increased total antioxidant power and molecular antioxidant levels (total ascorbate, glutathione and tocopherols). F2.7 improved the primary metabolism of stressed maize plants; for example, it increased in several individuals of soluble carbohydrates, organic acids, amino acids, and fatty acids. Interestingly, to reduce stress impact, F2.7 accumulated some compatible solutes including total soluble sugars, sucrose and proline. Hence, this comprehensive assessment recommends the potentials of actinobacterial cell-free extract as an alternative ecofriendly approach to improve crop growth and quality under water deficit conditions.
Asunto(s)
Aclimatación/efectos de los fármacos , Sequías , Streptomyces/metabolismo , Zea mays/fisiología , Actinobacteria/aislamiento & purificación , Actinobacteria/metabolismo , Antiinfecciosos/farmacología , Antioxidantes/farmacología , Ácido Ascórbico/metabolismo , Ácidos Grasos , Flavonoides/farmacología , Peróxido de Hidrógeno/metabolismo , Peroxidación de Lípido , Fotosíntesis , Filogenia , Reguladores del Crecimiento de las Plantas/metabolismo , ARN Ribosómico 16S/genética , Arabia Saudita , Sideróforos/metabolismo , Streptomyces/clasificación , Streptomyces/genética , Streptomyces/aislamiento & purificación , Estrés Fisiológico/efectos de los fármacos , Zea mays/crecimiento & desarrolloRESUMEN
NK-lysins are antimicrobial peptides (AMPs) that participate in the innate immune response and also have several pivotal roles in various biological processes. Such multifunctionality is commonly found among intrinsically disordered proteins. However, NK-lysins have never been systematically analyzed for intrinsic disorder. To fill this gap, the amino acid sequences of NK-lysins from various species were collected from UniProt and used for the comprehensive computational analysis to evaluate the propensity of these proteins for intrinsic disorder and to investigate the potential roles of disordered regions in NK-lysin functions. We analyzed abundance and peculiarities of intrinsic disorder distribution in all-known NK-lysins and showed that many NK-lysins are expected to have substantial levels of intrinsic disorder. Curiously, high level of intrinsic disorder was also found even in two proteins with known 3D-strucutres (NK-lysin from pig and human granulysin). Many of the identified disordered regions can be involved in protein-protein interactions. In fact, NK-lysins are shown to contain three to eight molecular recognition features; i.e. short structure-prone segments which are located within the long disordered regions and have a potential to undergo a disorder-to-order transition upon binding to a partner. Furthermore, these disordered regions are expected to have several sites of various posttranslational modifications. Our study shows that NK-lysins, which are AMPs with a set of prominent roles in the innate immune response, are expected to abundantly possess intrinsically disordered regions that might be related to multifunctionality of these proteins in the signal transduction pathways controlling the host response to pathogenic agents.
Asunto(s)
Algoritmos , Antiinfecciosos/química , Antígenos de Diferenciación de Linfocitos T/química , Proteolípidos/química , Secuencia de Aminoácidos , Animales , Antiinfecciosos/metabolismo , Antígenos de Diferenciación de Linfocitos T/metabolismo , Biología Computacional , Humanos , Modelos Moleculares , Familia de Multigenes , Conformación Proteica , Proteolípidos/metabolismo , Homología de Secuencia de Aminoácido , PorcinosRESUMEN
This study was performed to identify the expression patterns of the cathelicidin genes in a local chicken breed and to evaluate the antimicrobial activities of the cathelicidin peptides against pathogenic bacteria. This analysis revealed that the coding regions of CATH-1, -2, and -3 genes contain 447 bp, 465 bp, and 456 bp, respectively, and encode proteins of 148, 154, 151 amino acids, respectively. The complete amino acid sequences of the cathelicidin peptides are similar to those found in Meleagris gallopavo, Phasianus colchicus, and Coturnix coturnix, and show high sequence identity to their Columba livia and Anas platyrhynchos counterparts. In contrast, these avian peptides shared a very low sequence identity with the mammalian cathelicidins. The analysis further revealed that the cathelicidin genes are expressed in various organ and tissues. We also show that the CATH peptides 1, 2, 3 and their amide-modified structures possess potent antimicrobial activities against both Gram-positive and Gram-negative pathogens, with these bacteria being affected to different extents. The antimicrobial activities of the peptides are slightly lower than those of their amide analogs. Computational analysis revealed that pre-pro-cathelicidins are hybrid proteins that contain ordered domains and functional intrinsically disordered regions. Furthermore, high structural and sequence variability of mature cathelicidins is a strong indication of their rather disordered nature. It is likely that intrinsic disorder is needed for the multifarious functionality of these antimicrobial peptides. Our analyses indicated that cathelicidin peptides require further study to better understand their full potentials in the treatment of diseases in both humans and animals. The data obtained for synthetic avian peptides will help elucidating of their potential applications in the pharmaceutical industry.
Asunto(s)
Antiinfecciosos/metabolismo , Catelicidinas/metabolismo , Pollos/inmunología , Desinfectantes/metabolismo , Amidas/química , Animales , Antiinfecciosos/química , Biodiversidad , Catelicidinas/química , Catelicidinas/genética , Biología Computacional , Desinfectantes/química , Evolución Molecular , Humanos , Mamíferos , Filogenia , Alineación de Secuencia , Homología Estructural de Proteína , TranscriptomaRESUMEN
In this study we identified the expression patterns of ß-defensin-9 in chickens from Saudi Arabia, evaluated the antimicrobial activities of synthetic chicken ß-defensin-9 (sAvBD-9) against pathogenic bacteria and fungi, and investigated the mode of action of sAvBD-9 on bacterial cells. The AvBD-9 gene of Saudi chickens encodes a polypeptide of 67 amino acids, which is highly similar to the polypeptide in duck, quail, and goose (97%, 86%, and 87%, respectively) and shares a low sequence similarity with the mammalian defensins. AvBD-9 is expressed in various organs and tissues of Saudi chickens and inhibits the growth of both Gram-negative and Gram-positive bacteria, as well as showing activity against unicellular and multicellular fungi (Aspergillus flavus, A. niger, and Candida albicans). sAvBD-9 completely inhibited the growth of both Gram-positive and Gram-negative bacterial strains as well as Candida albicans. The haemolytic effects of sAvBD-9 were limited. Morphological analysis by TEM revealed that sAvBD-9 induces shortening and swelling of Staphylococcus aureus and Shigella sonni cells, opens holes and deep craters in their envelopes, and leads to the release of their cytoplasmic content. Our data shed light on the potential applications of sAvBD-9 in the pharmaceutical industry.