Search

The effect of cadmium in the root architecture of Cucumis sativus L. seedlings was determined. Primary root length and lateral root density of C. sativus L. seedlings exposed to 10, 20, 30, 50 and 100 ppm concentrations of Cd2+ was monitoring. The results show that at high concentrations of Cd occurs a lower growth in primary root length, where 50 and 100 ppm of Cd concentrations inhibit the primary root elongation. On the other hand, lateral root density formed increased when seedlings were exposed to higher concentrations of Cd2+. In 100 ppm treatment the highest lateral root density (19.2) was observed almost five times higher than control (4.0). The C. sativus L. root architecture is most affected at 50 and 100 ppm of Cd2+

Pseudomonas rhodesiae GRC140 is an endophytic bacterium isolated from the roots of Typha latifolia collected in a Cd-contaminated site. This bacterium has biochemical abilities similar to those exerted by plant growth-promoting rhizobacteria. Moreover, it has been shown that P. rhodesiae GRC140 improves the growth of Arabidopsis thaliana seedlings in the absence and presence of Cd. The aim of this work was to determine the effect of P. rhodesiae GRC140 in Cucumis sativus L. growing in nutritive medium with and without Cd. For this, cucumber seeds were superficially disinfected and exposed to a suspension of P. rhodesiae GRC140. Inoculated seeds were placed in a nutritive medium with and without Cd, then were incubated at 28 oC for eight days. After incubation, seedlings were recovered and determined the length of the primary root, the number of roots per plant, hypocotyl length, and the fresh weight. The results showed that P. rhodesiae GRC140 negatively affects the growth of C. sativus L. seedlings grown in the absence of Cd. On the other hand, in Cd-exposed seedlings, P. rhodesiae GRC140 improves the growth of C. sativus L. These results suggest that P. rhodesiae GRC140 decreases the deleterious effect of Cd in C. sativus L.

Antimicrobial resistance is a great concern in public health. Therefore, it is necessary to obtain new compounds to treat diseases caused by bacteria. Medicinal plants are an alternative to search natural compounds to improve human health, including antioxidants, anti-inflammatory, and antimicrobials compounds. Costus pulverulentus (Costaceae) C. Presl is a plant used traditionally in Huasteca Potosina to treat bacterial infections. However, the compounds involved in this activity remain poorly understood. To determine the antibacterial activity of C. pulverulentus, an ethanolic extract was obtained. Plant stem was macerated in ethanol and then was fractionated with hexane, chloroform, ethyl acetate, acetone, ethanol, and methanol. Ethanolic extract and derived fractions were tested against bacteria by the disk-diffusion agar method. The results showed that the ethanolic extract of C. pulverulentus exerted activity against Chromobacterium violaceum CV026 and Bacillus sp. at 10 and 30 μg/disk, whereas only the methanolic fraction showed similar activity to complete extract. Fraction 8 obtained from methanolic fraction showed inhibitory activity against Bacillus sp., S. aureus, and S. aureus Oxacillin resistant. Gas Chromatography-Mass Spectrometry characterization of active fraction 8 showed that it contains vanillic acid and pcoumaric acid suggesting that they are involved in the antibacterial activity of C. pulverulentus.

Fractionated extraction of the leaves of Artemisia ludoviciana subsp. mexicana was performed, using hexane, dichloromethane and methanol, to obtain compounds of different polarity. Essential oils, aqueous decoction and hydroalcoholic extract were also obtained. Phytochemical profile was determined for each extract based on coloration and precipitation tests. Extracts were evaluated against three enterobacteria using the plate microdilution method. Chemical analysis revealed that dichloromethane fraction has a greater variety of compounds than hexane and methanolic fractions. The content of compounds of dichloromethane fraction correlates with the highest antimicrobial activity observed, suggesting that metabolites responsible for antimicrobial effect are intermediate polarity. Regarding extracts, ethanolic extract exerts a better effect than the decoction, while the essential oil shows the same antibacterial effect at low concentrations. Results demonstrate that A. ludoviciana subsp. mexicana has a great variety of compounds, which, according to their nature, can be eluted with solvents of different polarity. These compounds contribute to the antibacterial effect attributed to this plant.