Mario Rodríguez-Monroy

The effects of cold-pretreatment, auxins and carbon source on anther culture of rice

The effects of a cold pretreatment, the concentration of different auxins (2,4-D, NAA and IAA) and the type of carbon source (maltose and sucrose) on the induction of callus from anthers of three parental lines and four rice F1 hybrids (Japonica × Indica, Indica × Japonica) were studied. The results indicated that a cold pretreatment was essential for the induction of callus from anthers of the parental lines and the F1 hybrids. These effects were genotype dependent. Auxins were essential for the induction of callus, and the type and concentration of auxins also influenced this process, as well as the type of carbon source. The greatest induction of callus was by the hybrid Morelos A92 × Koshihikari after a cold pretreatment of 8 days using 10.74 μM α–napthaleneacetic acid and 30 g l−1 maltose.

Broth rheology and morphological analysis of Solanum chrysotrichum cultivated in a stirred tank

Solanum chrysotrichum cell cultures were grown in a stirred tank bioreactor and their rheological and morphological behaviour were evaluated. The culture broths exhibited non-Newtonian and shear-thinning characteristics. Pseudoplasticity of the broths was governed by their biomass concentration. The roundness of aggregates measured as the elliptical form factor (EFF) had important changes. At the beginning of the culture the aggregates with an EFF lower than 2 represented 52% of the population, but in stationary phase the proportion increased to 77%. Whereas the size of aggregates did not change 80% of the population had an area lower than 0.1 mm2. Overall, these results indicate that the shape of the aggregate therefore needs to be considered when studying plant broth rheology.

Monoterpenoid Oxindole Alkaloid Production by Uncaria tomentosa (Willd) D.C. Cell Suspension Cultures in a Stirred Tank Bioreactor

Cell growth, monoterpenoid oxindole alkaloid (MOA) production, and morphological properties of Uncaria tomentosa cell suspension cultures in a 2‐L stirred tank bioreactor were investigated. U. tomentosa (cell line green Uth‐3) was able to grow in a stirred tank at an impeller tip speed of 95 cm/s (agitation speed of 400 rpm), showing a maximum biomass yield of 11.9 ± 0.6 g DW/L and a specific growth rate of 0.102 d−1. U. tomentosa cells growing in a stirred tank achieved maximum volumetric and specific MOA concentration (467.7 ± 40.0 μg/L, 44.6 ± 5.2 μg/g DW) at 16 days of culture. MOA chemical profile of cell suspension cultures growing in a stirred tank resembled that of the plant. Depending on culture time, from the total MOA produced, 37–100% was found in the medium in the bioreactor culture. MOA concentration achieved in a stirred tank was up to 10‐fold higher than that obtained in Erlenmeyer flasks (agitated at 110 rpm). In a stirred tank, average area of the single cells of U. tomentosa increased up to 4‐fold, and elliptical form factor increased from 1.40 to 2.55, indicating enlargement of U. tomentosa single cells. This work presents the first report of U. tomentosagreen cell suspension cultures that grow and produce MOA in a stirred tank bioreactor.

Analysis of morphological characteristics of Solanum chrysotrichum cell suspension cultures

Cell size distribution of Solanum chrysotrichum cell suspension cultures was determined using mechanical sieving and an image analysis system. The results were compared using the sieve size (<0.25, 0.25–0.50, 0.5–1.0 and >1.00 mm) as the criterion. Mechanical sieving as well as image analysis showed that S. chrysotrichum cultures developed in shake flasks present a similar tendency to increase in aggregate size as growth persists. However, there are considerable differences in the values of each fraction. Fractions obtained by mechanical sieving were characterized by image analysis demonstrating that an inefficient separation of the cell population exists. The results demonstrate that digital image analysis was more precise than mechanical sieving to describe the cell size distribution changes occurring during cell growth. It was also possible to achieve a total characterization of S. chrysotrichum morphology.

Influence of Auxins and Sucrose in Monoterpenoid Oxindole Alkaloid Production by Uncaria tomentosa Cell Suspension Cultures

Growth and alkaloid production in Uncaria tomentosa cell suspension cultures were studied in Murashige and Skoog medium supplemented with 10 μM 2,4‐dichlorophenoxyacetic acid, 10 μM kinetin, and 58 mM sucrose for maintenance and with 10 μM indole‐3‐acetic acid, 10 μM kinetin, and 58 mM sucrose for production. A U. tomentosa pale Uth‐3 cell line, cultured in the production medium, showed a reduced lag phase and a specific growth rate (μ) of 0.27 day−1, while cells growing in the maintenance medium showed μ = 0.20 day−1. U. tomentosacells growing in the production medium produced monoterpenoid oxindole alkaloids (MOA) in amounts of 10.2 ± 1.6 μg g−1 dry weight (DW). The chemical profile of MOA produced by in vitro cell cultures was similar to that found in the plant. After 10 subcultures, maximum MOA production decreased to 2.0 ± 0.7 μg g−1 DW, while tryptamine alkaloids (TA) were produced with a maximum of 6.2 ± 0.4 μg g−1 DW. The increase of initial sucrose concentration up to 145 mM in the production medium enhanced the cell biomass by 3.2‐fold (from 10.2 ± 0.1 to 32.8 ± 1.1 g DW L−1), reduced μ from 0.27 to 0.23 day−1, and provoked a substantial accumulation of TA (23.1 ± 4.7 μg g−1 DW). A high sucrose concentration stimulated MOA production in the maintenance medium (2.7 ± 0.5 μg g−1 DW), even in the presence of 2,4‐dichlorophenoxyacetic acid.

Food Quality Influences Ovarian Development in Scyphophorus acupunctatus (Coleoptera: Dryophthoridae)

Abstract This paper describes the anatomy of the female reproductive system of the agave weevil, Scyphophorus acupunctatus Gyllenhall (Coleoptera: Dryophthoridae). This insect is considered a primary pest of agave (Agave spp.) (Asparagaceae) and tuberose (Polianthes tuberosa L.) (Asparagaceae) in Mexico. Developmental biology and ovarian maturation of laboratory-reared S. acupunctatus fed a meridic diet was compared with individuals fed tuberose bulbs. Ovarian maturation was classified according to ovariole and follicle differentiation, as well as the presence of follicular relics. This classification yielded 1 parous and 3 nulliparous stages. We found that ovarian maturation was delayed for those weevils fed the meridic diet compared with those fed tuberose bulbs. Also, the greatest number of ovarian follicles occurred in individuals fed tuberose bulbs; however, this relationship changed with the age of the insect. Proximal length and follicular area also varied according to age and type of diet. We believe that the ovarian developmental stages described here for S. acupunctatus could be a useful method to monitor parity status of field populations when assessing the effectiveness of control programs for this weevil pest.