RESUMEN
The development of fast-growing/short cropping period oyster mushroom (Pleurotus species) having good taste is one of the important needs of mushroom growers. Pleurotus djamor strain woody1, collected recently from the dead wood, has a short cropping period of 30 days but a moderately acceptable taste. One of the cultivated Pleurotus spp., P. djamor strain MDU1, has good taste but a long cropping period of 47 days. Thus, genetic improvement of P. djamor was carried out between these two strains by pairing monokaryons (anastomosis) to develop elite hybrid strains having a short cropping period and good taste. Monokaryons of parental strains showed variation in time required for germination; i.e., basidiospores of P. djamor strain woody1 germinated and developed monokaryotic colonies in 6 days, whereas that of P. djamor strain MDU1 developed monokaryotic colonies in 8 days of incubation. In addition, variation in the growth rate and morphology of the monokaryotic mycelia of both parental strains was noticed, and fast-growing monokaryons were selected for anastomosis. Out of 60 crosses made between mycelia of monokaryotic isolates of both parental strains, 20 crosses showed clamp connection, indicating that they were successful crosses. Out of 20 hybrids, two hybrid strains, viz., W2M4 and W4M4, exhibited higher yields than their parents. They exhibited the short cropping period trait, good taste attribute, and some specific volatile metabolites. This study showed that the developed two hybrid varieties, having desirable agronomic traits, could be used in mushroom farming to increase the mushroom grower's income.
Asunto(s)
Pleurotus , Pleurotus/genética , Hibridación de Ácido NucleicoRESUMEN
Eicosapentaenoic acid (EPA) and arachidonic acid (ARA) are long-chain polyunsaturated fatty acids (PUFAs) that play a significant role in human growth and development, which deficiency can trigger several metabolic-related diseases. Since the availability of PUFA sources is limited, there arises a need to explore alternative sources. Therefore, the present study aimed to investigate whether an Escherichia coli which are engineered with Δ5Des-Iso gene isolated from Isochrysis sp. could be utilized to synthesize PUFAs. Full-length gene Δ5Des-Iso (1149 bp) was isolated from Isochrysis sp. that encodes 382 amino acids and identified as Δ5-desatruase gene using different bioinformatic analysis. Heterologous gene expression was carried out in E. coli having Δ5Des-Iso with precursor fatty acids. The Δ5Des-Iso produced novel fatty acids of EPA (ω-3) and ARA (ω-6) as respective products were identified by GC-MS. Gene expression and PUFA synthesis in E. coli were optimized by temperature, time, and concentrations of precursor fatty acid substrates. Δ5Des-Iso RNA transcript level was inversely proportional to the time and fatty acid synthesis. And, the significant production of EPA (4.1 mg/g) and ARA (8.3 mg/g) in total fatty acids was observed in E. coli grown at 37 °C for 24 h with 25 µM of external fatty acid substrate as an optimum growth conditions. E. coli could be used as alternative organism to synthesis PUFAs and widely applicable in many nutraceuticals and pharmaceuticals industry for human use.
Asunto(s)
Escherichia coli , Ácido Graso Desaturasas , Ácidos Grasos Omega-3/biosíntesis , Ácidos Grasos Omega-6/biosíntesis , Haptophyta/genética , Microalgas/genética , Microorganismos Modificados Genéticamente , Proteínas de Plantas , Escherichia coli/genética , Escherichia coli/metabolismo , Ácido Graso Desaturasas/genética , Ácido Graso Desaturasas/metabolismo , Ácidos Grasos Omega-3/genética , Haptophyta/enzimología , Microalgas/enzimología , Microorganismos Modificados Genéticamente/genética , Microorganismos Modificados Genéticamente/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
OBJECTIVES: To express a Δ6-desaturase gene and produce gamma-linolenic acid (GLA) and stearidonic acid (SDA) in prokaryotic expression system (Escherichia coli), and analyze its substrate specificity in the omega-3 fatty acid biosynthetic pathway. RESULTS: Full-length ORF (1448 bp) of Δ6Des-Iso was isolated from Isochrysis sp. and characterized using multiple sequence alignment, phylogenetic analysis, transmembrane domain, and protein tertiary structure. Δ6Des-Iso is a front-end desaturase consisting of three conserved histidine domains and a cytochrome b5 domain. Δ6Des-Iso was cloned and expressed in E. coli with the production of GLA and SDA. Recombinant E. coli utilized 27 and 8% of exogenously supplied alpha-linolenic acid (ALA) and linoleic acid (LA) to produce 6.3% of SDA and 2.3% of GLA, respectively, suggesting that isolated Δ6Des-Iso is specific to the omega-3 pathway. CONCLUSION: For the first time production of GLA and SDA in a prokaryotic system was achieved.
Asunto(s)
Ácidos Grasos Insaturados/metabolismo , Haptophyta/enzimología , Linoleoil-CoA Desaturasa/metabolismo , Microalgas/enzimología , Proteínas Recombinantes/metabolismo , Escherichia coli/genética , Ácidos Grasos Insaturados/química , Haptophyta/genética , Linoleoil-CoA Desaturasa/química , Linoleoil-CoA Desaturasa/genética , Microalgas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Especificidad por SustratoRESUMEN
Maize is the third important major food crop. Breeding for low phytate maize genotypes is an effective strategy for decreasing the content of kernel phytic acid (a chelator of cations such as Ca(2+) and Fe(3+) ) and thereby increasing the bioavailability of nutritive minerals in human diet and animal feed. Previous studies have established that a mutant plant with a lpa2-2 allele accumulates less phytic acid in seeds. Therefore, the marker assisted backcross breeding (MABB), which involves introgression of lpa2-2 recessive allele (which confer low phytate trait) from a lpa2-2 mutant line into a well-adapted line using backcrosses and selection of lines possessing lpa2-2 allele in each backcross population using molecular markers, is an effective strategy for developing low phytate maize. So far, no studies have developed any lpa2-2 allele specific molecular markers for this purpose. Here, using backcross and selfed progenies, obtained by crossing low phytate mutant line 'EC 659418' (i.e. donor of lpa2-2 allele) into agronomically superior line 'UMI395', we have validated that a SSR marker 'umc2230', located 0.4 cM downstream of lpa2-2, cosegregate, in a Mendelian fashion, with low phytic acid trait. Therefore umc2230 can be dependably used in MABB for the development of low phytate maize.
Asunto(s)
Marcadores Genéticos , Ácido Fítico/metabolismo , Selección Genética , Zea mays/genética , Alelos , Cruzamiento , Calcio/metabolismo , Humanos , Hierro/metabolismo , Proteínas de PlantasRESUMEN
BACKGROUND: Several species of the genus Cassia are known for their antioxidant, antimicrobial and antidiabetic activities, but some of the lesser-known Cassia species, e.g. C. renigera, C. biflora and C. laevigata have not been studied for their biological activities. RESULTS: Methanol extract of C. laevigata was fractionated by preparative thin-layer chromatography. The resulting six different fractions were tested against Fusarium oxysporum and Aspergillus niger for their antifungal activity. Due to higher antifungal activity of fraction 1 of C. laevigata, this was further analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC), resulting in distinct separation of one compound at a retention time of 7.2 min with an absorbance of 252 nm. Further, this compound was analyzed by gas chromatography-mass spectrometry (GC-MS) for its putative structural identification. Mass spectra of this compound resembled the spectra of anthraquinone 1-carboxylic acid by NIST library search. The genomic-level expression of chalcone synthase, a key enzyme involved in the biosynthesis of polyketides, was increased in C. laevigata when compared to other Cassia species. CONCLUSIONS: This study provides an insight into the higher antifungal activity of C. laevigata, including the identification of anthraquinone 1-carboxylic acid, which may be responsible for the antifungal activity.