Biology

The soil is a subsystem where biological activity and recycling of nutrients maintain terrestrial ecosystems. Free living amoebae (FLA) release the nutrients fixed in bacteria but they have specificity in its prey. Although the FLA are world-wide distributed, the composition of species of a particular site depends on the environment. In this study, it was proposed to determine species richness of naked amoebae in a preserved soil and a degraded one from the Cutac subriver basin in Zapotitlán de las Salinas, Puebla. In the preserved soil 6 species of Acanthamoeba have been identified, one of Vahlkampfia and 2 of Echinamoeba; whereas in the degraded soil only 2 species of Acanthamoeba have been identified, one of Platyamoeba and one of Vahlkampfia. In spite of the existing tension in soils of semi-arid environments, these provide the necessary microatmospheres for the development of different species of naked amoebae.

Intracellular symbiosis is a widespread and important biological phenomenon. One of its most studied in vitro models, is the one that is carried out between Legionella bacteria and free living amoebae. In the present study, it was possible to identify and isolate endosymbiotic bacteria pathogenic to free living amoebae, which were found in the sediments of pool water. Identification experiments, such as their size, its dependency to L-cisteine, nontermophilic behaviour, Gram staining, colonial morphology and mainly their ability to infect and multiply within free living amoebae, allow us to promote a deeper study about the phylogenetic characterization of these bacteria, since it could be some Legionella species not previously studied. Also in this study are described some useful methodologies for the identification and isolation of endosymbiotic bacteria from free living amoebae. These techniques could be helpful for future studies directed to bacteria that have some symbiotic relationship with amoebae or some other protozoa.

Free living amoebae (FLA) inhabit a wide range of environments. The most reported genus of naked amoebae in studies about soil protozoa are: Naegleria, Hartmannella, Vahlkampfia and Acanthamoeba. FLA are able to establish symbiotic relationships with other microorganisms. The most common and studied case is the one of Legionella, although other species of bacterial endosymbionts of FLA have been identified, such as: Pseudomonas, Chlamydia, and Rickettsia. In this study, it was proposed to determine the species richness of naked amoebae that are present in a preserved naked soil from the Cutac subriver basin in Zapotitlán de las Salinas, Puebla. At the same time, it was proposed to determine the presence of bacterial endosymbionts of FLA, in order to describe the type of endosymbiosis that they present, to determine its species by culture, morphological, biochemical and molecular methods. Finally, it was proposed to try to determine the possible causes of endosymbiosis at preserved naked soils of semi-arid environments and its ecological importance. To the moment, several species of Acanthamoeba have been identified and a species of Echinamoeba. In addition, 2 different types of endosyimbiotic bacteria have been detected, both with colonial morphology similar to the one of Legionella sp., but with a slightly different coloration among them. The presence of plasmid DNA in both stocks of bacteria was also detected, which suggests the evaluation of phenotypes related to bacterial endosyimbiosis in amoebae.

The effects of an ethanolic extract of Cannabis sativa, on the contraction of the gastrocnemium muscle of the rat, were studied taking into account within these the possible interaction of the D9-THC (which is the active principle of this plant) with propilenglycol used as a vehicle. Registries of muscular fatigue were made, during which the extract was applied at high (4 mg/kg) and low (0.5 mg/kg) doses of D9-THC, as well as of the pure vehicle, to be able to measure their possible interaction. The data was compared against a control group, which did not received any treatment during the registries.

D9-THC in the high dose produced an increase of the muscular response in comparison with the control group, this effect is harnessed as well by the higher doses of the vehicle. As far as the low doses, an increase also took place but in a smaller scale, which was not harnessed by the lower doses of the vehicle. Apparently, propilenglycol used as a vehicle for D9-THC, produces an additive effect on muscular response, being administered only in higher doses.

Lichens are biological partnerships of ample diffusion, which are found in a great variety of habitats. Saxicolous lichens are developed on rocks, for this reason they take part in the first stages of soil formation. In the present study, 14 units that were found in the North, East, South and West faces of the Perritos cliff were collected, that is located in La Marquesa forest in the State of México; of which only 6 were identified at species level and 1 at genus level. Identification experiments such as: type of thallus classification, obtaining cuts for microscope observation, type of algae identification, spores, ascs, and some chemical reactions such as reacting with KOH, allow us to provide a brief information about the relationship of these organisms with their habitat, as well as interesting data about the presence of some species in the different faces of this cliff. Some of these data could be of aid for future studies directed to the diversity of saxicolous lichens in the surroundings of Valle de México.