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The survival of Azospirillum brasilense Cd and Sp-245 in the rhizosphere of wheat and tomato plants and in 23 types of plant-free sterilized soils obtained from a wide range of environments in Israel and Mexico was evaluated. Large numbers of A. brasilense cells were detected in all the rhizospheres tested, regardless of soil type, bacterial strain, the(More)
The recent application of molecular phylogeny to environmental samples has resulted in the discovery of an abundance of unique and previously unrecognized microorganisms. The vast majority of this microbial diversity has proved refractory to cultivation. Here, we describe a universal method that provides access to this immense reservoir of untapped(More)
Because they are ubiquitous in a range of aquatic environments and culture methods are relatively advanced, cyanobacteria may be useful models for understanding the extent of evolutionary adaptation of prokaryotes in general to environmental gradients. The roles of environmental variables such as light and nutrients in influencing cyanobacterial genetic(More)
The giant columnar cardon cactus (Pachycereus pringlei) appears to have an ailment(s) that is destroying a large number of plants. The causal agent(s), whether biotic or abiotic, has yet to be determined. Two forms of symptom development have been recorded. The first is a circular tissue decay on a branch leading to death of the growing tip. In this case,(More)
An isolate of the filamentous cyanobacterium Microcoleus sp. was obtained from black mangrove aerial root (pneumatophore) and inoculated onto young mangrove seedlings to evaluate N2-fixation and root-colonization capacities of the bacterium under in vitro conditions in closed-system experiments. N2 fixation (acetylene reduction) gradually increased with(More)
Two isolates of the diazotrophic filamentous cyanobacterium Microcoleus chthonoplastes, one obtained from black mangrove (Avicennia germinans) pneumatophores and one from cyanobacterial mats, were inoculated onto young mangrove seedlings to evaluate nitrogen transfer from the bacterium to the plants under in vitro conditions in closed system experiments.(More)
Nitrogen fixation and colonization by associative cyanobacteria in the aerial roots (pneumatophores) of black mangrove trees was evaluated in situ at Balandra lagoon, Baja California Sur, Mexico, for 18 consecutive months. Year-round vertical zonation of cyanobacterial colonization was determined along the pneumatophores. The bottom part close to the(More)
Black mangrove (Avicennia germinans) seedlings (n=555) were grown from field-collected propagules for 3 months in a new type of terrestrial nursery. They were grown in clusters of five plants, and then they were transplanted to a clear-cut zone in a lagoon fringed by a mangrove forest at Laguna de Balandra, Baja California Sur, Mexico. Survival and plant(More)
A Synechococcus serotype is found preferentially in surface marine waters Abstract In marine ecosystems, gradients of light, temperature, and nutrients occur horizontally (coastal to offshore) and vertically. The extent to which microorganisms acclimate or speciate in response to these gradients is under active investigation. Strain isolation data (e.g.,(More)
Inoculation with Azospirillum brasilense Cd o f two leguminous species, soybean (Glycine max) and cowpea (Vigna unguiculata), demonstrated that: (1) A. brasilense significantly increased proton efflux from their roots; (2) inoculation reduced plant membrane potential (in soybean), (3) inoculation changed the phospholipid quantity in plant membranes of calli(More)
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