A novel coconut-malt extract medium increases growth rate of morels in pure culture.

Morels are gourmet wild edible mushrooms that can grow on several substrates with significant growth rate variations. Such variations have hindered the development of a standardized culture media to promote morel's sustainable production. The aim of this study is developing a novel culture media that takes advantage of coconut water as a complementary component of culture media. Coconut water has been extensively used as a growth-promoting component for plant tissue cultures; however, its application as component of fungi cultivation medium has not been fully developed. This study confirms that coconut water can be efficiently used as culture media component for morels using a kinetic characterization. Morchella sp. kinetic growth is evaluated in different cultures: agar, malt extract agar (MEA), lactose, coconut water (15%) and combinations of them. Kinetic growth parameters (lag phase, λ and maximum specific growth rate, µmax) are estimated using primary modeling methods. Among the selected models, the best fit is achieved using Baranyi's model. A significant increase from 15.8% to 43.4% of the µmax values was observed when culture media (agar, lactose, MEA) is supplemented with coconut water. The largest values of µmax are obtained in MEA-coconut cultures (21.13 ± 0.43-22.57 ± 0.35). Micro-sclerotia and late sclerotia are observed in all cultures containing coconut water justifying the development of a feasible and cost-effective way of culturing morels. The results demonstrate that coconut water can be used for formulation of standard media for morel cultivation leading to a cheap alternative to produce dense mycelium and promote sclerotia formation.

Functional properties of flours and protein concentrates of 3 strains of the edible mushroom Pleurotus ostreatus.

Pleurotus ostreatus is an edible mushroom with significant nutritional properties and highly valuable protein concentrates can be obtained from its fruit bodies. Functional properties of flours and protein concentrates derived from 3 Pleurotus ostreatus strains (PCM, POS and hybrid PCM × POS) were evaluated in this investigation. Fruit bodies were produced on wheat straw substrate, flours were obtained from dried and grinded fruit bodies and protein concentrates were extracted from flours by alkaline solubilization. For all 3 strains, pale yellow flours were obtained and protein concentrates showed a grayish brown color. Flour bulk densities ranged from 0.52 to 0.64 g/mL, a higher value than those for protein concentrates, i.e. 0.30-0.35 g/mL. The highest water absorption capacities (WAC) were observed for flours (300-418.8%) while protein concentrates presented higher oil absorption capacity (OAC) (173.3-214.1%). Flours and protein concentrates presented a minimal gelation concentration of 2%. Protein concentrates showed a higher foam capacity formation (FC) at pH 8. Likewise, flours and protein concentrates presented higher foam stability (FS) at alkaline pH (8 and 10). Emulsion activity index (EAI) for flours ranged from 3.96 to 26.68 m2 g-1 whereas for protein concentrates ranged from 1.55 to 10.28 m2 g-1. These results indicate that flours and protein concentrates from P. ostreatus have remarkable functional properties, valuable in food industry where foaming and emulsifying properties are required.

Utilización de marcadores ITS e ISSR para la caracterización molecular de cepas híbridas de Pleurotus djamor / Use of ITS and ISSR markers in the molecular characterisation of Pleurotus djamor hybrid strains

Antecedentes. La caracterización molecular de cepas silvestres de Pleurotus es importante para la conservación del germoplasma y su posterior uso en la mejora genética. No se han realizado estudios moleculares con los monocariontes utilizados para la producción de cepas híbridas, ni de las cepas reconstituidas obtenidas al aparear tales monocariontes. Por consiguiente, la caracterización molecular de cepas dicarióticas parentales, híbridas y reconstituidas, así como de cepas monocarióticas, es de suma importancia. Objetivos. Caracterizar molecularmente cepas dicarióticas silvestres e híbridas, así como cepas monocarióticas de Pleurotus djamor. Métodos. Se recolectaron cinco cepas silvestres de P. djamor en diferentes estados de México y se identificaron molecularmente mediante la secuenciación de la región ITS1-5.8-ITS2 con los oligonucleótidos universales ITS1 e ITS4. Se seleccionaron dos cepas silvestres y se generaron cuatro cepas híbridas por apareamiento de neohaplontes compatibles. Para la caracterización molecular de las cepas monocarióticas y dicarióticas seleccionadas y producidas se utilizaron seis marcadores ISSR. Resultados. Con los marcadores ITS se obtuvo un producto de amplificación de 700 pb en las cinco cepas silvestres con una similitud del 99-100% con la especie P. djamor. Con los marcadores ISSR se obtuvieron un total de 95 fragmentos con un 99% de polimorfismo. Conclusiones. Las cepas silvestres se identificaron como P. djamor. Los marcadores ISSR generaron bandas polimórficas en las cepas monocarióticas y dicarióticas, y separaron ambos tipos de cepas. El alto grado de polimorfismo indica la diversidad genética de P. djamor, una ventaja para la producción de hongos y para la mejora de la especie (AU)

Background. Molecular characterisation of wild type Pleurotus species is important for germplasm conservation and its further use for genetic improvement. No molecular studies have been performed with monokaryons used for producing hybrid strains, either with the reconstituted strains obtained by pairing those monokaryons. The molecular characterisation of parental dikaryons, hybrid, and reconstituted strains as well as monokaryotic strains, is therefore of utmost importance. Aims. To carry out the molecular identification of Pleurotus djamor strains, i.e. dikaryotic wild type strains, hybrid strains, and the monokaryotic strains used for the hybrid formation. Methods. Five wild type strains of P. djamor from different states in Mexico were collected and molecularly identified by sequencing the ITS1-5.8-ITS2 region using ITS1 and ITS4 universal oligonucleotides. Four hybrid strains were obtained by pairing neohaplonts of two wild type strains selected. Six ISSR markers were used for the molecular characterisation of monokaryotic and dikaryotic strains. Results. Using the ITS markers, an amplified product of 700bp was obtained in five wild type strains, with a 99-100% similarity with P. djamor. A total of 95 fragments were obtained using the ISSR markers, with 99% of polymorphism. Conclusions. Wild type strains were identified as P. djamor, and were clearly grouped with Mexican strains from other states of Mexico. ISSR markers allowed the generation of polymorphic bands in monokaryotic and dikaryotic strains, splitting both types of strains. The high degree of polymorphism indicates the genetic diversity of P. djamor, an advantage in mushroom production and in the improving of the species (AU)

[Use of ITS and ISSR markers in the molecular characterisation of Pleurotus djamor hybrid strains]. / Utilización de marcadores ITS e ISSR para la caracterización molecular de cepas híbridas de Pleurotus djamor.

BACKGROUND: Molecular characterisation of wild type Pleurotus species is important for germplasm conservation and its further use for genetic improvement. No molecular studies have been performed with monokaryons used for producing hybrid strains, either with the reconstituted strains obtained by pairing those monokaryons. The molecular characterisation of parental dikaryons, hybrid, and reconstituted strains as well as monokaryotic strains, is therefore of utmost importance. AIMS: To carry out the molecular identification of Pleurotus djamor strains, i.e. dikaryotic wild type strains, hybrid strains, and the monokaryotic strains used for the hybrid formation. METHODS: Five wild type strains of P. djamor from different states in Mexico were collected and molecularly identified by sequencing the ITS1-5.8-ITS2 region using ITS1 and ITS4 universal oligonucleotides. Four hybrid strains were obtained by pairing neohaplonts of two wild type strains selected. Six ISSR markers were used for the molecular characterisation of monokaryotic and dikaryotic strains. RESULTS: Using the ITS markers, an amplified product of 700bp was obtained in five wild type strains, with a 99-100% similarity with P. djamor. A total of 95 fragments were obtained using the ISSR markers, with 99% of polymorphism. CONCLUSIONS: Wild type strains were identified as P. djamor, and were clearly grouped with Mexican strains from other states of Mexico. ISSR markers allowed the generation of polymorphic bands in monokaryotic and dikaryotic strains, splitting both types of strains. The high degree of polymorphism indicates the genetic diversity of P. djamor, an advantage in mushroom production and in the improving of the species.

Spasmolytic effect of Alternanthera repens on isolated rat ileum.

Abstract Context: Alternanthera repens (L.) Kuntze (Amaranthaceae) is widely used in Mexican traditional medicine for the treatment of gastrointestinal disorders that are mainly related to diarrhea. Objective: The aim of the present study was to investigate the spasmolytic effect of hexane (Hx), methanol (Me) and aqueous (Aq) extracts as well as chromatographic Me fractions (F1-F6) of A. repens in rat ileum. Materials and methods: Dried and powdered aerial parts were used to obtain the extracts. The rat ileum preparations were incubated in Tyrode's solution gassed (95% O2-5% CO2) at 37 °C. The effect on the contractile response of isolated ileum was evaluated by obtaining cumulative concentration-response curves to CaCl2, KCl, 5-HT and acetylcholine in the absence and presence of different doses of Aq (0.56-2.09 mg/mL), Me (0.24-0.91 mg/mL) and Hx (0.24-0.91 mg/mL) extracts, as well as six Me fractions of 0.66 mg/mL (F1 to F6). Results: The A. repens Me (0.24 mg/mL) caused an inhibitory response of the Ca2+-induced contractions, with IC50 values of 0.18 ± 0.061 and 0.67 ± 0.061 mM in the presence and absence of the Me, respectively. Me fractions F2 to F4 presented a significant inhibitory effect (F(3,8) = 60.17, p = 0.0001), causing a reduction in the CaCl2-induced contractions and shifting the Ca2+ (0.39 to 1.81 mM) concentration-response curves to the right. With respect to the effect on 5-HT-induced contractions, IC50 values Hx extract (0.24 mg/mL) were 5.44 ± 0.08 × 10-6 M and 3.38 ± 0.07 × 10-6 M in the presence and absence of the Hx, respectively. Discussion and conclusion: The spasmolytic effects induced by Me and Me fractions of A. repens may involve a serotonergic and Ca2+ influx blockade mechanisms, which may justify the use of A. repens extracts as an effective traditional treatment against diarrhea.