@article {1206,
	title = {Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {109},
	year = {2012},
	month = {2012 Aug 21},
	pages = {13674-9},
	abstract = {<p>Microbial productivity at hydrothermal vents is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at vents are lacking. We used a combination of cultivation, molecular, and geochemical tools to verify pure culture H(2) threshold measurements for hyperthermophilic methanogenesis in low-temperature hydrothermal fluids from Axial Volcano and Endeavour Segment in the northeastern Pacific Ocean. Two Methanocaldococcus strains from Axial and Methanocaldococcus jannaschii showed similar Monod growth kinetics when grown in a bioreactor at varying H(2) concentrations. Their H(2) half-saturation value was 66 μM, and growth ceased below 17-23 μM H(2), 10-fold lower than previously predicted. By comparison, measured H(2) and CH(4) concentrations in fluids suggest that there was generally sufficient H(2) for Methanocaldococcus growth at Axial but not at Endeavour. Fluids from one vent at Axial (Marker 113) had anomalously high CH(4) concentrations and contained various thermal classes of methanogens based on cultivation and mcrA/mrtA analyses. At Endeavour, methanogens were largely undetectable in fluid samples based on cultivation and molecular screens, although abundances of hyperthermophilic heterotrophs were relatively high. Where present, Methanocaldococcus genes were the predominant mcrA/mrtA sequences recovered and comprised \~{}0.2-6\% of the total archaeal community. Field and coculture data suggest that H(2) limitation may be partly ameliorated by H(2) syntrophy with hyperthermophilic heterotrophs. These data support our estimated H(2) threshold for hyperthermophilic methanogenesis at vents and highlight the need for coupled laboratory and field measurements to constrain microbial distribution and biogeochemical impacts in the deep sea.</p>},
	keywords = {Archaea, Biodiversity, Coculture Techniques, DNA, Ribosomal, Ecosystem, Gases, Geography, Hydrogen, Hydrothermal Vents, Kinetics, Methane, Molecular Sequence Data, Temperature, Time Factors, Water Microbiology},
	issn = {1091-6490},
	doi = {10.1073/pnas.1206632109},
	author = {Ver Eecke, Helene C and Butterfield, David A and Huber, Julie A and Lilley, Marvin D and Olson, Eric J and Roe, Kevin K and Evans, Leigh J and Merkel, Alexandr Y and Cantin, Holly V and Holden, James F}
}
@article {799,
	title = {Distribution of the Ixodes ricinus-like ticks of eastern North America.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {92},
	year = {1995},
	month = {1995 Jul 3},
	pages = {6284-8},
	abstract = {We analyzed the geographic distribution of the Ixodes ricinus-like ticks in eastern North America by comparing the mitochondrial 16S rDNA sequences of specimens sampled directly from the field during the 1990s. Two distinct lineages are evident. The southern clade includes ticks from the southeastern and middle-eastern regions of the United States. The range of the northern clade, which appears to have been restricted to the northeastern region until the mid-1900s, now extends throughout the northeastern and middle-eastern regions. These phyletic units correspond to northern and southern taxa that have previously been assigned specific status as Ixodes dammini and Ixodes scapularis, respectively. The expanding range of I. dammini appears to drive the present outbreaks of zoonotic disease in eastern North America that include Lyme disease and human babesiosis.},
	keywords = {Animals, Base Sequence, Demography, DNA Primers, DNA, Mitochondrial, DNA, Ribosomal, Geography, Mitochondria, Molecular Sequence Data, Phylogeny, Polymerase Chain Reaction, Population, RNA, Ribosomal, 16S, Ticks, United States},
	issn = {0027-8424},
	author = {Rich, S M and Caporale, D A and Telford, S R and Kocher, T D and Hartl, D L and Spielman, A}
}
@article {800,
	title = {Norway rats as reservoir hosts for Lyme disease spirochetes on Monhegan Island, Maine.},
	journal = {J Infect Dis},
	volume = {168},
	year = {1993},
	month = {1993 Sep},
	pages = {687-91},
	abstract = {To determine whether the agent of Lyme disease, Borrelia burgdorferi, may be maintained in the absence of its usual white-footed mouse reservoir host, Ixodes dammini ticks from an island where mice are absent were examined. Prevalence of spirochetal infection was described for ticks removed from mammals, birds, and vegetation on Monhegan Island, Maine. Forty percent of adult I. dammini removed from vegetation were infected. Norway rats were heavily infested with ticks, and > 60\% of such ticks contained spirochetes. Other hosts were less frequently infested by ticks, and few such ticks were infected by spirochetes. The prevalence of antibody to B. burgdorferi was 23\% in dogs and cats; 4\% of island residents had Lyme disease. Thus, rats maintain Lyme disease spirochetes on Monhegan Island, and there may be transmission of this agent by I. dammini to island residents and their pets.},
	keywords = {Animals, Animals, Domestic, Antibodies, Bacterial, Borrelia burgdorferi Group, Cats, Disease Reservoirs, Disease Vectors, Dogs, Geography, Humans, Incidence, Lyme Disease, Maine, Rats, Ticks},
	issn = {0022-1899},
	author = {Smith, R P and Rand, P W and Lacombe, E H and Telford, S R and Rich, S M and Piesman, J and Spielman, A}
}
