Ultrastructural and microbial analyses of cellulose degradation in leaf-cutter ant colonies.

Leaf-cutter ants (Atta and Acromyrmex) use fresh leaves to cultivate a mutualistic fungus (Leucoagaricus gongylophorus) for food in underground gardens. A new ant queen propagates the cultivar by taking a small fragment of fungus from her parent colony on her nuptial flight and uses it to begin her own colony. Recent research has shown that the ants' fungus gardens are colonized by symbiotic bacteria that perform important functions related to nitrogen fixation and have been implicated in contributing to plant biomass degradation.

Production of selenium nanoparticles in Pseudomonas putida KT2440.

Selenium (Se) is an essential element for the cell that has multiple applications in medicine and technology; microorganisms play an important role in Se transformations in the environment. Here we report the previously unidentified ability of the soil bacterium Pseudomonas putida KT2440 to synthesize nanoparticles of elemental selenium (nano-Se) from selenite. Our results show that P.

Surface structures involved in plant stomata and leaf colonization by shiga-toxigenic Escherichia coli o157:h7.

Shiga-toxigenic Escherichia coli (STEC) O157:H7 uses a myriad of surface adhesive appendages including pili, flagella, and the type 3 secretion system (T3SS) to adhere to and inflict damage to the human gut mucosa. Consumption of contaminated ground beef, milk, juices, water, or leafy greens has been associated with outbreaks of diarrheal disease in humans due to STEC. The aim of this study was to investigate which of the known STEC O157:H7 adherence factors mediate colonization of baby spinach leaves and where the bacteria reside within tainted leaves.

Ultrastructure of the wild rice Oryza grandiglumis (Gramineae) in Costa Rica.

Oryza grandiglumis is a wild species of rice endemic to tropical America. This species was first found in 1998 in the wetlands of Caño Negro, located in the northern part of Costa Rica. Twenty five plants of O.

[Ultrastructural description of Euglena pailasensis (Euglenozoa) from Rincón de la Vieja volcano, Guanacaste, Costa Rica].

The euglenoids are unicellular eukaryotic flagellates living in a diversity of soils and aquatic environments and ecosystems. This study describes the ultrastructure of an euglenoid isolated from the surface of a boiling mud pool with temperatures ranging from 38 to 98 degrees C and pH 2 - 4. The hot mud pool is located in Area de Pailas de Barro, Las Pailas, Rincón de la Vieja Volcano, Guanacaste, Costa Rica.

[A new species of Euglena (Euglenozoa: Euglenales) isolated from extreme environments in "boiling mudflats" of Rincón de la Vieja volcano, Costa Rica].

A new species of euglena isolated from a hot and acid mud pool located in Las Pailas de Barro, Volcán Rincón de la Vieja, Costa Rica is described. This species inhabits hot and acid environments. Euglena pailasensis sp.

Ultrastructure of Oryza glumaepatula, a wild rice species endemic of tropical America.

Orv'za gluniaepatula is a perennial wild rice species, endemic to tropical America, previously known as the Latin American race of Orrza rufipogon. In Costa Rica, it is found in the northern region of the country, mainly in the wetland of the Medio Queso River, Los Chiles, Alajuela. It is diploid, of AA type genome and because of its genetic relatedness to cultivated rice it is included in the O.

Ultrastructural morphologic description of the wild rice species Oryza latifolia (Poaceae) in Costa Rica.

The wild rice species Oryza latifolia is endemic to Tropical America, allotetraploid and has a CCDD genome type. It belongs to the officinalis group of the genus Oryza. This species is widely distributed throughout the lowlands of Costa Rica and it is found on different life zones, having great morphologic diversity.

Characterization of a photosynthetic Euglena strain isolated from an acidic hot mud pool of a volcanic area of Costa Rica.

Abstract Conspicuous green patches on the surface of an acidic hot mud pool located near the Rincón de la Vieja volcano (northwestern Costa Rica) consisted of apparently unialgal populations of a chloroplast-bearing euglenoid. Morphological and physiological studies showed that it is a non-flagellated photosynthetic Euglena strain able to grow in defined mineral media at temperatures up to 40 degrees C and exhibiting higher thermotolerance than Euglena gracilis SAG 5/15 in photosynthetic activity analyses. Molecular phylogeny studies using 18S rDNA and GapC genes indicated that this strain is closely related to Euglena mutabilis, another acid-tolerant photosynthetic euglenoid, forming a clade deeply rooted in the Euglenales lineage.

[Bacterial present in the xylem of coffee (Rubiaceae: coffea arabica) with "Crespera" disease].

"Crespera" is an infectious disease of coffee plants that affects both the coffee production and the economy of the coffee producer countries. This disease affects morphologically the plant: long and narrow leaves with wavy borders and marginal necrosis; strong chlorosis results in drying of the leave, and leads to bad conditions of the plant. The internodes are short, producing the appearance of multiple sprouts in the axial sprout, the flowers can turn greenish, and the plant can present branches with severe symptoms, and branches without apparent symptoms at the same time.