title: Spirochaeta bajacaliforniensis sp. n. from a microbial mat community at Laguna Figueroa, Baja California Norte, Mexico.
abstract: A new anaerobic spirochete was isolated from anaerobic muds beneath the laminated sediment in the evaporite flat at Laguna Figueroa, Baja California Norte, Mexico.  The organism is a member of the stratified microbial community involved in the deposition of the laminated sediments in the lagoon.  The size of the spirochete is 0.3 by 30 micrometers, with a wave amplitude of 0.5 micrometer and a wavelength of 1.25 micrometers.  The periplasmic flagella have a 1-2-1 arrangement.  The outer membrane of the modified Gram-negative cell wall (the sheath) is irregularly crenulated and has a sillon.  The growth medium contained yeast extract, trypticase, cellobiose, sodium thioglycolate and at least 20% natural seawater.  Chemically defined artificial seawater media did not support growth.  Optimal growth occurred with a seawater concentration of 80% at 36 degrees C and a pH of 7.5.  Glucose was fermented to acetate, ethanol, carbon dioxide and hydrogen.  The guanine + cytosine content of the DNA was 50 mol %.  The spirochete body reacts positively to antibodies raised against eukaryotic brain tubulin protein.  On the basis of its free-living anaerobic habitat, its unique morphological and physiological characteristics and G+C ratio, it is proposed that this isolated be considered a new species and names Spirochaeta bajacaliforniensis.
authors.affiliation: Department of Biology, Boston University, MA 02215, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Fracek
authors.forename: J F
authors.initials: JF
authors.lastname: Stolz
mesh_terms: D001426:Bacterial Proteins / Q000302:isolation & purification*; D005075:Biological Evolution; D002244:Carbon / Q000502:physiology; D003470:Culture Media; D003596:Cytosine / Q000378:metabolism; D004783:Environmental Microbiology; D005947:Glucose / Q000378:metabolism; D006147:Guanine / Q000378:metabolism; D008386:Marine Biology; D008800:Mexico; D013142:Spirochaeta / Q000145:classification / Q000302:isolation & purification* / Q000502:physiology* / Q000648:ultrastructure; D013559:Symbiosis; D014404:Tubulin
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D014404:Tubulin; D006147:Guanine; D002244:Carbon; D003596:Cytosine; D005947:Glucose