1,369 research outputs found
A new purple sulfur bacterium from saline littoral sediments, Thiorhodotvibrio winogradskyi gen. nov. and sp. nov.
No full textTwo strains of a new purple sulfur bacterium were isolated in pure culture from the littoral sediment of a saline lake (Mahoney Lake, Canada) and a marine microbial mat from the North Sea island of Mellum, respectively. Single cells were vibrioid-to spirilloid-shaped and motile by means of single polar flagella. Intracellular photosynthetic membranes were of the vesicular type. As photosynthetic pigments, bacteriochlorophyll a and the carotenoids lycopene, rhodopin, anhydrorhodovibrin, rhodovibrin and spirilloxanthin were present.
Hydrogen sulfide and elemental sulfur were used under anoxic conditions for phototrophic growth. In addition one strain (06511) used thiosulfate. Carbon dioxide, acetate and pyruvate were utilized by both strains as carbon sources. Depending on the strain propionate, succinate, fumarate, malate, tartrate, malonate, glycerol or peptone may additionally serve as carbon sources in the light. Optimum growth rates were obtained at pH 7.2, 33 °C, 50 mol m-2 s-1 intensity of daylight fluorescent tubes and a salinity of 2.2–3.2% NaCl. During growth on sulfide, up to ten small sulfur globules were formed inside the cells. The strains grew microaerophilic in the dark and exhibited high specific respiration rates. No vitamins were required for growth. The DNA base composition was 61.0–62.4 mol% G+C.
The newly isolated bacterium belongs to the family chromatiaceae and is described as a member of a new genus and species, Thiorhodovibrio winogradskyi gen. nov. and sp. nov. with the type strain SSP1, DSM No. 6702
Noted Author and Scholar Visits
No full textThe new Cassandra Voss Center at St. Norbert is celebrating a canonical figure in gender studies in America with a full year of programming dedicated to her work.https://digitalcommons.snc.edu/snc_magazine_archives_2013-2018/1004/thumbnail.jp
Summer 2013: Community-Wide Conversation Focuses on Recruiting and Retaining Young Talent
No full textA significant discussion on regional progress – and ways to relay that progress to members of Generation Y, in particular – kicked off at St. Norbert on Oct. 15. Futurist, economist and author Rebecca Ryan talked about means by which communities like the Greater Green Bay area can enhance their ability to recruit and retain the next generation of talent.https://digitalcommons.snc.edu/snc_magazine_archives_2013-2018/1084/thumbnail.jp
In a Class by Himself
No full textThis year, for the first time, an alumni presenter will be among those taking part in Alumni College. C.J. Hribal ’79, author and Marquette University professor, will offer a lecture on the art of mystery in fiction. Hribal joins St. Norbert professors (some of them SNC alums, too!) on the faculty of the annual event that draws alums back to campus for a weekend opportunity to reconnect.https://digitalcommons.snc.edu/snc_magazine_archives_2013-2018/1002/thumbnail.jp
Norbert Waszek, "La escuela hegeliana"
No full textAuthor: Norbert Waszek. Translated by Pedro Sepúlveda Zambran
Norbert Waszek, "La escuela hegeliana"
No full textAuthor: Norbert Waszek. Translated by Pedro Sepúlveda Zambran
Spring 2015: Thought Leaders Weigh Issues of Violence and Reconciliation
No full textThe “Thought Leaders Weigh Issues of Violence and Reconciliation” article from St. Norbert College Magazine’s Spring 2015 issue recounts a powerful dialogue between author bell hooks and sociologist Beth Richie during hooks’ campus residency. Centered on the theme “Ending Violence: How We Change,” the conversation explored systemic violence, personal accountability, and the transformative potential of love and community. Richie, an advisor to the NFL on domestic violence, and hooks, a renowned social justice scholar, emphasized the need for honest dialogue, healing, and grassroots change—urging individuals to start small, act locally, and build inclusive spaces of understanding and care.https://digitalcommons.snc.edu/snc_magazine_archives_2013-2018/1244/thumbnail.jp
Continuous chemotrophic growth and respiration of Chromatiaceae species at low oxygen concentrations
No full textEndogenous and maximum respiration rates of nine purple sulfur bacterial strains were determined. Endogenous rates were below 10 nmol O2 · (mg protein · min)-1 for sulfur-free cells and 15–35 nmol O2 · (mg protein · min)-1 for cells containg intracellular sulfur globules. With sulfide as electron-donating substrate respiration rates were considerably higher than with thiosulfate. Maximum respiration rates of Thiocystis violacea 2711 and Thiorhodovibrio winogradskyi SSP1 (254.8 and 264.2 nmol O2 · (mg protein · min)-1, respectively) are similar to those of aerobic bacteria. Biphasic respiration curves were obtained for sulfur-free cells of Thiocystis violacea 2711 and Chromatium vinosum 2811. In Thiocystis violacea the rapid and incomplete oxidation of thiosulfate was five times faster than the oxidation of stored sulfur. A high affinity of the respiratoty system for oxygen (K m =0.3–0.9 M O2, V max=260 nmol O2 · (mg protein · min)-1 with sulfide as substrate, K m =0.6–2.4 M O2, V max=14–40 nmol O2 · (mg protein · min)-1 with thiosulfate as substrate), for sulfide (K m =0.47 M, V max=650 nmol H2S · (mg protein × min)-1, and for thiosulfate (K m =5–6 M, V max =24–72 nmol S2O 3 2- · (mg protein · min)-1 was obtained for different strains. Respiration of Thiocystis violacea was inhibited by very low concentrations of NaCN (K i =1.7 M) while CO concentrations of up to 300 M were not inhibitory. The capacity for chemotrophic growth of six species was studied in continuous culture at oxygen concentrations of 11 to 67 M. Thiocystis violacea 2711, Amoebobacter roseus 6611, Thiocapsa roseopersicina 6311 and Thiorhodovibrio winogradskyi SSP1 were able to grow chemotrophically with thiosulfate/acetate or sulfide/acetate. Chromatium vinosum 2811 and Amoebobacter purpureus ML1 failed to grow under these conditions. During shift from phototrophic to chemotrophic conditions intracellular sulfur and carbohydrate accumulated transiently inside the cells. During chemotrophic growth bacteriochlorophyll a was below the detection limit
Evolution, Science and Faith: Grandeur in an Evolutionary View of Life
No full textIn this lecture, St. Norbert College welcomed Brown University\u27s Kenneth R. Miller to campus for the Spring 2025 Dr. Benjamin T. Chu Distinguished Lecture, “Evolution, Science and Faith: Grandeur in an Evolutionary View of Life .
Miller—renowned biologist, author and advocate for the dialogue between science and religion—shared powerful insights on evolution, human purpose and the intersection of reason and belief
Spring 2018: Advocate Speaks to the Heart
No full textAdriana Bink ’20 connected her internship with Brown County CASA and her honors studies by helping bring foster-care advocate and author Ashley Rhodes-Courter to St. Norbert College, where she highlighted the life-changing role of court-appointed special advocates.https://digitalcommons.snc.edu/snc_magazine_archives_2013-2018/1493/thumbnail.jp
- …
