Submerged monoxenic culture of the entomopathogenic nematode, <Emphasis Type="Italic">Steinernema carpocapsae</Emphasis> CABA01, in a mechanically agitated bioreactor: Evolution of the hydrodynamic and mass transfer conditions

This study is the first to describe the evolution of both hydrodynamic and oxygen transfer conditions during the submerged culture of the entomopathogenic nematode, Steinernema carpocapsae CABA01 (an indigenous strain isolated within the State of Hidalgo, Mexico), and its symbiotic bacterium, Xenorhabdus nematophila, using an internal-loop mechanically agitated bioreactor of 4.5 L of liquid volume. Concentrations up to 217,306 viable nematodes per mL, with 94% in infective juvenile (IJ) stage (i.e., 204,444 IJ/mL), were achieved in 16 days of bioprocess. The Reynolds number (Re) was used as an index of the actual hydrodynamic conditions, and it varied within the interval 5,150 < Re (dimensionless) < 9,440, involving apparent culture broth viscosity changes from 3 to 5.4 mPa s during the processing. The aeration efficiency was expressed on the basis of the volumetric oxygen transfer coefficient, k _L a, which varied within the range 0.026 to 0.170 s⁻¹.     

Effects of sensorial denervation induced by capsaicin injection at birth or on day three of life,on puberty,induced ovulation and pregnancy

Evidence that ovarian innervation plays a role in the regulation of ovarian functions has been widely reported. The present study analyzed the effects of treating neonatal rats with capsaicin on: the onset of puberty, serum hormone levels, timing of first vaginal estrus, ovulation rates, ovarian and uterine weights, follicular development, and noradrenaline concentration in the ovaries. The study was based on two experimental models: untouched rats and hemispayed animals. The results indicate that newborns treated with capsaicin did not show changes in the onset of puberty, though the number of ova shed by these animals was lower than in control rats. The number of follicles counted in the ovaries of newborn, or 3-day old-capsaicin-treated animals, was significantly lower and showed an increase in the number of atretic follicles compared to vehicle treated rats. All capsaicin treated animals copulated, but only 6/23 delivered pups. The number of ova shed by capsaicin-treated animals after eCG or eCG-hCG treatment was significantly lower than in the control group. Present results could indicate that some specific neural information registered in the ovary is sent to the central nervous system, and that such information plays a role in the mechanism regulating ovarian function.     

Cadmium mimics the in vivo effects of estrogen in the uterus and mammary gland

It has been suggested that environmental contaminants that mimic the effects of estrogen contribute to disruption of the reproductive systems of animals in the wild, and to the high incidence of hormone-related cancers and diseases in Western populations. Previous studies have shown that functionally, cadmium acts like steroidal estrogens in breast cancer cells as a result of its ability to form a high-affinity complex with the hormone binding domain of the estrogen receptor. The results of the present study show that cadmium also has potent estrogen-like activity in vivo. Exposure to cadmium increased uterine wet weight, promoted growth and development of the mammary glands and induced hormone-regulated genes in ovariectomized animals. In the uterus, the increase in wet weight was accompanied by proliferation of the endometrium and induction of progesterone receptor (PgR) and complement component C3. In the mammary gland, cadmium promoted an increase in the formation of side branches and alveolar buds and the induction of casein, whey acidic protein, PgR and C3. In utero exposure to the metal also mimicked the effects of estrogens. Female offspring experienced an earlier onset of puberty and an increase in the epithelial area and the number of terminal end buds in the mammary gland.     

Characterization of films made with chayote tuber and potato starches blending with cellulose nanoparticles

The aim of this study was to characterize chayotextle starch films reinforced with cellulose (C) and cellulose nanoparticle (CN) (at concentrations of 0.3%, 0.5%, 0.8% and 1.2%), using thermal, mechanical, physicochemical, permeability, and water solubility tests. C was acid-treated to obtain CN. The films were prepared by casting; potato starch and C were used as the control. The solubility of the starch films decreased with the addition of C and CN compared with its respective film without C and CN. No statistical difference (α = 0.05) was found in the films added with different concentrations of C and CN. In general, the mechanical properties were improved with the addition of C and CN, and higher values of tensile strength and elastic modulus were determined in the films reinforced with CN. The melting temperature and enthalpy increased with the addition of C and CN, and the values of both thermal parameters were higher in the films with CN than with C; the enthalpy value of the film decreased when the concentration of C or CN increased in the composite. Low concentration of C and CN is better distributed in the matrix film. The addition of C and CN in the starch films improved some mechanical, barrier, and functional properties.