The Experts below are selected from a list of 77058 Experts worldwide ranked by ideXlab platform
Nancy B. Valentine - One of the best experts on this subject based on the ideXlab platform.
-
the hydration number n of calcium dipicolinate trihydrate cadp nh2o and its effect on the ir spectra of sporulated Bacillus Bacteria
Vibrational Spectroscopy, 2010Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Previous results have shown a unique "quartet" of peaks in the infrared spectra of the sporulated phase of Bacillus Bacteria, the four peaks being observed reproducibly for many different species of Bacillus endospores. We consistently observe peaks at 766, 725, 701, and 659 cm-1 and with the same relative amplitudes, as well as other spore peaks at 1441, 1277, 1015 cm-1. We have previously suggested that the peaks arise from calcium dipicolinate, not the conjugate acid. In this paper we conduct a theoretical and experimental study to show that the IR peaks not only arise from the calcium dipicolinate, a known spore component, but specifically the trihydrate salt, CaDP•3H2O. This is shown by calculating the absolute IR intensities of the lone dipicolinate dianion, the calcium salt, as well as the mono-, di- and tri-hydrate salts of calcium dipicolinate. The quartet peaks arise from the crystalline trihydrate salt as we verify both experimentally as well as using quantum chemistry methods. Using a method whereby the calculated intensities are not normalized, only the trihydrate spectrum shows low frequency modes (below 1000 cm-1, including the quartet) having intensities comparable to those of the pyridine ring. The vibrational modes in this part of themore » spectrum are associated with many internal coordinate motions including contributions from the Ca2+ counterion and the three waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. Index Headings: Infrared, calcium dipicolinate, Bacillus, Bacteria, Endospores« less
-
The hydration number n of calcium dipicolinate trihydrate, CaDP·nH2O, and its effect on the IR spectra of sporulated Bacillus Bacteria
Vibrational Spectroscopy, 2010Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Previous results have shown a unique "quartet" of peaks in the infrared spectra of the sporulated phase of Bacillus Bacteria, the four peaks being observed reproducibly for many different species of Bacillus endospores. We consistently observe peaks at 766, 725, 701, and 659 cm-1 and with the same relative amplitudes, as well as other spore peaks at 1441, 1277, 1015 cm-1. We have previously suggested that the peaks arise from calcium dipicolinate, not the conjugate acid. In this paper we conduct a theoretical and experimental study to show that the IR peaks not only arise from the calcium dipicolinate, a known spore component, but specifically the trihydrate salt, CaDP•3H2O. This is shown by calculating the absolute IR intensities of the lone dipicolinate dianion, the calcium salt, as well as the mono-, di- and tri-hydrate salts of calcium dipicolinate. The quartet peaks arise from the crystalline trihydrate salt as we verify both experimentally as well as using quantum chemistry methods. Using a method whereby the calculated intensities are not normalized, only the trihydrate spectrum shows low frequency modes (below 1000 cm-1, including the quartet) having intensities comparable to those of the pyridine ring. The vibrational modes in this part of themore » spectrum are associated with many internal coordinate motions including contributions from the Ca2+ counterion and the three waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. Index Headings: Infrared, calcium dipicolinate, Bacillus, Bacteria, Endospores« less
-
the infrared spectra of Bacillus Bacteria part i vegetative Bacillus versus sporulated cells and the contributions of phospholipids to vegetative infrared spectra
Applied Spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. Valentine, Yinfong Su, Helen W Kreuzermartin, Karen L Wahl, Brian H Clowers, David S WunschelAbstract:This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus Bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or vegetative state and that vegetative cells (or cell debris) can contribute to the spore spectra. A distinct feature at ∼1739 cm−1 appears to be unique to vegetative cell spectra and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate that the band arises from a lipid-soluble species such as an ester or phospholipid carbonyl bond and are consistent with it being either phosphatidyl glycerol (PG) or phosphatidylethanolamine (PE), two major classes of phospholipids found in vegetative cells of Bacillus species. A companion work discusses bands associated with the sporulated state.
-
The Infrared Spectra of Bacillus Bacteria Part I: Vegetative Bacillus versus Sporulated Cells and the Contributions of Phospholipids to Vegetative Infrared Spectra
Applied spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. Valentine, Karen L Wahl, Brian H Clowers, Helen W. Kreuzer-martin, David S WunschelAbstract:This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus Bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or vegetative state and that vegetative cells (or cell debris) can contribute to the spore spectra. A distinct feature at ∼1739 cm−1 appears to be unique to vegetative cell spectra and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate that the band arises from a lipid-soluble species such as an ester or phospholipid carbonyl bond and are consistent with it being either phosphatidyl glycerol (PG) or phosphatidylethanolamine (PE), two major classes of phospholipids found in vegetative cells of Bacillus species. A companion work discusses bands associated with the sporulated state.
-
The infrared spectra of Bacillus Bacteria part II: sporulated Bacillus--the effect of vegetative cells and contributions of calcium dipicolinate trihydrate, CaDP.3H2O.
Applied spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Our previous paper showed that certain infrared (IR) peaks, e.g., the peak at 1739 cm−1, are due to varying (trace) amounts of vegetative cells amongst the Bacillus spores and that these and other vegetative bands are associated with lipid-soluble compounds, likely an ester or phospholipid. This work investigates the infrared spectra of eight different sporulated Bacillus Bacteria. For the endospores it is observed that peaks at 1441, 1277, and 1015 cm−1 along with a distinct quartet of peaks at 766, 725, 701, and 659 cm−1 are clearly associated with calcium dipicolinate trihydrate, CaDP·3H2O. It is emphasized that the spore peaks, especially the quartet, arise from the calcium dipicolinate trihydrate and not from dipicolinic acid or other dipicolinate hydrate salts. The CaDP·3H2O infrared peaks and the effects of hydration are studied using quantum chemistry in the PQS software package. The quartet is associated with many modes including contributions from the Ca2+ counterion and hydration waters including Ca–O–H bends, H2O–Ca–O torsions, and O–C–O bends. The 1441 and 1015 cm−1 modes are planar pyridine modes with the 1441 cm−1 mode primarily a ring C–N stretch and the 1015 cm−1 mode primarily a ring C–C stretch.
Timothy J. Johnson - One of the best experts on this subject based on the ideXlab platform.
-
the hydration number n of calcium dipicolinate trihydrate cadp nh2o and its effect on the ir spectra of sporulated Bacillus Bacteria
Vibrational Spectroscopy, 2010Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Previous results have shown a unique "quartet" of peaks in the infrared spectra of the sporulated phase of Bacillus Bacteria, the four peaks being observed reproducibly for many different species of Bacillus endospores. We consistently observe peaks at 766, 725, 701, and 659 cm-1 and with the same relative amplitudes, as well as other spore peaks at 1441, 1277, 1015 cm-1. We have previously suggested that the peaks arise from calcium dipicolinate, not the conjugate acid. In this paper we conduct a theoretical and experimental study to show that the IR peaks not only arise from the calcium dipicolinate, a known spore component, but specifically the trihydrate salt, CaDP•3H2O. This is shown by calculating the absolute IR intensities of the lone dipicolinate dianion, the calcium salt, as well as the mono-, di- and tri-hydrate salts of calcium dipicolinate. The quartet peaks arise from the crystalline trihydrate salt as we verify both experimentally as well as using quantum chemistry methods. Using a method whereby the calculated intensities are not normalized, only the trihydrate spectrum shows low frequency modes (below 1000 cm-1, including the quartet) having intensities comparable to those of the pyridine ring. The vibrational modes in this part of themore » spectrum are associated with many internal coordinate motions including contributions from the Ca2+ counterion and the three waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. Index Headings: Infrared, calcium dipicolinate, Bacillus, Bacteria, Endospores« less
-
The hydration number n of calcium dipicolinate trihydrate, CaDP·nH2O, and its effect on the IR spectra of sporulated Bacillus Bacteria
Vibrational Spectroscopy, 2010Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Previous results have shown a unique "quartet" of peaks in the infrared spectra of the sporulated phase of Bacillus Bacteria, the four peaks being observed reproducibly for many different species of Bacillus endospores. We consistently observe peaks at 766, 725, 701, and 659 cm-1 and with the same relative amplitudes, as well as other spore peaks at 1441, 1277, 1015 cm-1. We have previously suggested that the peaks arise from calcium dipicolinate, not the conjugate acid. In this paper we conduct a theoretical and experimental study to show that the IR peaks not only arise from the calcium dipicolinate, a known spore component, but specifically the trihydrate salt, CaDP•3H2O. This is shown by calculating the absolute IR intensities of the lone dipicolinate dianion, the calcium salt, as well as the mono-, di- and tri-hydrate salts of calcium dipicolinate. The quartet peaks arise from the crystalline trihydrate salt as we verify both experimentally as well as using quantum chemistry methods. Using a method whereby the calculated intensities are not normalized, only the trihydrate spectrum shows low frequency modes (below 1000 cm-1, including the quartet) having intensities comparable to those of the pyridine ring. The vibrational modes in this part of themore » spectrum are associated with many internal coordinate motions including contributions from the Ca2+ counterion and the three waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. Index Headings: Infrared, calcium dipicolinate, Bacillus, Bacteria, Endospores« less
-
the infrared spectra of Bacillus Bacteria part i vegetative Bacillus versus sporulated cells and the contributions of phospholipids to vegetative infrared spectra
Applied Spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. Valentine, Yinfong Su, Helen W Kreuzermartin, Karen L Wahl, Brian H Clowers, David S WunschelAbstract:This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus Bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or vegetative state and that vegetative cells (or cell debris) can contribute to the spore spectra. A distinct feature at ∼1739 cm−1 appears to be unique to vegetative cell spectra and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate that the band arises from a lipid-soluble species such as an ester or phospholipid carbonyl bond and are consistent with it being either phosphatidyl glycerol (PG) or phosphatidylethanolamine (PE), two major classes of phospholipids found in vegetative cells of Bacillus species. A companion work discusses bands associated with the sporulated state.
-
The Infrared Spectra of Bacillus Bacteria Part I: Vegetative Bacillus versus Sporulated Cells and the Contributions of Phospholipids to Vegetative Infrared Spectra
Applied spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. Valentine, Karen L Wahl, Brian H Clowers, Helen W. Kreuzer-martin, David S WunschelAbstract:This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus Bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or vegetative state and that vegetative cells (or cell debris) can contribute to the spore spectra. A distinct feature at ∼1739 cm−1 appears to be unique to vegetative cell spectra and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate that the band arises from a lipid-soluble species such as an ester or phospholipid carbonyl bond and are consistent with it being either phosphatidyl glycerol (PG) or phosphatidylethanolamine (PE), two major classes of phospholipids found in vegetative cells of Bacillus species. A companion work discusses bands associated with the sporulated state.
-
The infrared spectra of Bacillus Bacteria part II: sporulated Bacillus--the effect of vegetative cells and contributions of calcium dipicolinate trihydrate, CaDP.3H2O.
Applied spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Our previous paper showed that certain infrared (IR) peaks, e.g., the peak at 1739 cm−1, are due to varying (trace) amounts of vegetative cells amongst the Bacillus spores and that these and other vegetative bands are associated with lipid-soluble compounds, likely an ester or phospholipid. This work investigates the infrared spectra of eight different sporulated Bacillus Bacteria. For the endospores it is observed that peaks at 1441, 1277, and 1015 cm−1 along with a distinct quartet of peaks at 766, 725, 701, and 659 cm−1 are clearly associated with calcium dipicolinate trihydrate, CaDP·3H2O. It is emphasized that the spore peaks, especially the quartet, arise from the calcium dipicolinate trihydrate and not from dipicolinic acid or other dipicolinate hydrate salts. The CaDP·3H2O infrared peaks and the effects of hydration are studied using quantum chemistry in the PQS software package. The quartet is associated with many modes including contributions from the Ca2+ counterion and hydration waters including Ca–O–H bends, H2O–Ca–O torsions, and O–C–O bends. The 1441 and 1015 cm−1 modes are planar pyridine modes with the 1441 cm−1 mode primarily a ring C–N stretch and the 1015 cm−1 mode primarily a ring C–C stretch.
Stephen D. Williams - One of the best experts on this subject based on the ideXlab platform.
-
the hydration number n of calcium dipicolinate trihydrate cadp nh2o and its effect on the ir spectra of sporulated Bacillus Bacteria
Vibrational Spectroscopy, 2010Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Previous results have shown a unique "quartet" of peaks in the infrared spectra of the sporulated phase of Bacillus Bacteria, the four peaks being observed reproducibly for many different species of Bacillus endospores. We consistently observe peaks at 766, 725, 701, and 659 cm-1 and with the same relative amplitudes, as well as other spore peaks at 1441, 1277, 1015 cm-1. We have previously suggested that the peaks arise from calcium dipicolinate, not the conjugate acid. In this paper we conduct a theoretical and experimental study to show that the IR peaks not only arise from the calcium dipicolinate, a known spore component, but specifically the trihydrate salt, CaDP•3H2O. This is shown by calculating the absolute IR intensities of the lone dipicolinate dianion, the calcium salt, as well as the mono-, di- and tri-hydrate salts of calcium dipicolinate. The quartet peaks arise from the crystalline trihydrate salt as we verify both experimentally as well as using quantum chemistry methods. Using a method whereby the calculated intensities are not normalized, only the trihydrate spectrum shows low frequency modes (below 1000 cm-1, including the quartet) having intensities comparable to those of the pyridine ring. The vibrational modes in this part of themore » spectrum are associated with many internal coordinate motions including contributions from the Ca2+ counterion and the three waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. Index Headings: Infrared, calcium dipicolinate, Bacillus, Bacteria, Endospores« less
-
The hydration number n of calcium dipicolinate trihydrate, CaDP·nH2O, and its effect on the IR spectra of sporulated Bacillus Bacteria
Vibrational Spectroscopy, 2010Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Previous results have shown a unique "quartet" of peaks in the infrared spectra of the sporulated phase of Bacillus Bacteria, the four peaks being observed reproducibly for many different species of Bacillus endospores. We consistently observe peaks at 766, 725, 701, and 659 cm-1 and with the same relative amplitudes, as well as other spore peaks at 1441, 1277, 1015 cm-1. We have previously suggested that the peaks arise from calcium dipicolinate, not the conjugate acid. In this paper we conduct a theoretical and experimental study to show that the IR peaks not only arise from the calcium dipicolinate, a known spore component, but specifically the trihydrate salt, CaDP•3H2O. This is shown by calculating the absolute IR intensities of the lone dipicolinate dianion, the calcium salt, as well as the mono-, di- and tri-hydrate salts of calcium dipicolinate. The quartet peaks arise from the crystalline trihydrate salt as we verify both experimentally as well as using quantum chemistry methods. Using a method whereby the calculated intensities are not normalized, only the trihydrate spectrum shows low frequency modes (below 1000 cm-1, including the quartet) having intensities comparable to those of the pyridine ring. The vibrational modes in this part of themore » spectrum are associated with many internal coordinate motions including contributions from the Ca2+ counterion and the three waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. Index Headings: Infrared, calcium dipicolinate, Bacillus, Bacteria, Endospores« less
-
the infrared spectra of Bacillus Bacteria part i vegetative Bacillus versus sporulated cells and the contributions of phospholipids to vegetative infrared spectra
Applied Spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. Valentine, Yinfong Su, Helen W Kreuzermartin, Karen L Wahl, Brian H Clowers, David S WunschelAbstract:This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus Bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or vegetative state and that vegetative cells (or cell debris) can contribute to the spore spectra. A distinct feature at ∼1739 cm−1 appears to be unique to vegetative cell spectra and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate that the band arises from a lipid-soluble species such as an ester or phospholipid carbonyl bond and are consistent with it being either phosphatidyl glycerol (PG) or phosphatidylethanolamine (PE), two major classes of phospholipids found in vegetative cells of Bacillus species. A companion work discusses bands associated with the sporulated state.
-
The Infrared Spectra of Bacillus Bacteria Part I: Vegetative Bacillus versus Sporulated Cells and the Contributions of Phospholipids to Vegetative Infrared Spectra
Applied spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. Valentine, Karen L Wahl, Brian H Clowers, Helen W. Kreuzer-martin, David S WunschelAbstract:This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus Bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or vegetative state and that vegetative cells (or cell debris) can contribute to the spore spectra. A distinct feature at ∼1739 cm−1 appears to be unique to vegetative cell spectra and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate that the band arises from a lipid-soluble species such as an ester or phospholipid carbonyl bond and are consistent with it being either phosphatidyl glycerol (PG) or phosphatidylethanolamine (PE), two major classes of phospholipids found in vegetative cells of Bacillus species. A companion work discusses bands associated with the sporulated state.
-
The infrared spectra of Bacillus Bacteria part II: sporulated Bacillus--the effect of vegetative cells and contributions of calcium dipicolinate trihydrate, CaDP.3H2O.
Applied spectroscopy, 2009Co-Authors: Timothy J. Johnson, Stephen D. Williams, Nancy B. ValentineAbstract:Our previous paper showed that certain infrared (IR) peaks, e.g., the peak at 1739 cm−1, are due to varying (trace) amounts of vegetative cells amongst the Bacillus spores and that these and other vegetative bands are associated with lipid-soluble compounds, likely an ester or phospholipid. This work investigates the infrared spectra of eight different sporulated Bacillus Bacteria. For the endospores it is observed that peaks at 1441, 1277, and 1015 cm−1 along with a distinct quartet of peaks at 766, 725, 701, and 659 cm−1 are clearly associated with calcium dipicolinate trihydrate, CaDP·3H2O. It is emphasized that the spore peaks, especially the quartet, arise from the calcium dipicolinate trihydrate and not from dipicolinic acid or other dipicolinate hydrate salts. The CaDP·3H2O infrared peaks and the effects of hydration are studied using quantum chemistry in the PQS software package. The quartet is associated with many modes including contributions from the Ca2+ counterion and hydration waters including Ca–O–H bends, H2O–Ca–O torsions, and O–C–O bends. The 1441 and 1015 cm−1 modes are planar pyridine modes with the 1441 cm−1 mode primarily a ring C–N stretch and the 1015 cm−1 mode primarily a ring C–C stretch.
Stefan Geisen - One of the best experts on this subject based on the ideXlab platform.
-
Microbial amendments alter protist communities within the soil microbiome
Soil Biology and Biochemistry, 2019Co-Authors: Wu Xiong, Qirong Shen, Sai Guo, Ida Karlsson, George A. Kowalchuk, Zixuan Jiao, Weibing Xun, Stefan GeisenAbstract:Plant-beneficial microbes improve while pathogens reduce plant performance. When introduced in soils, such microbes can induce entire microbiome changes. However, the impact of those microbial introductions on protists – key predators within the soil microbiome – remain unknown. Here, we tracked how soil protists respond to Bacterial (Bacillus and Ralstonia) and fungal (Trichoderma and Fusarium) introductions, with both microbial groups represented by one beneficial and one pathogenic taxon. We found that plant-beneficial Bacillus Bacteria change the protist community structure. This community-shift was likely induced by an increased fungi/Bacteria ratio, supported by a negative correlation of the fungi/Bacteria ratio with the relative abundance of phagotrophic protists across all treatments. Our results indicate that microbial introductions can impact protist communities, thereby altering microbiome-derived multi-functionality.
George A. Kowalchuk - One of the best experts on this subject based on the ideXlab platform.
-
Initial soil microbiome composition and functioning predetermine future plant health
Science advances, 2019Co-Authors: Zhong Wei, Qirong Shen, George A. Kowalchuk, Ville-petri Friman, Alexandre JoussetAbstract:Plant-pathogen interactions are shaped by multiple environmental factors, making it difficult to predict disease dynamics even in relatively simple agricultural monocultures. Here, we explored how variation in the initial soil microbiome predicts future disease outcomes at the level of individual plants. We found that the composition and functioning of the initial soil microbiome predetermined whether the plants survived or succumbed to disease. Surviving plant microbiomes were associated with specific rare taxa, highly pathogen-suppressing Pseudomonas and Bacillus Bacteria, and high abundance of genes encoding antimicrobial compounds. Microbiome-mediated plant protection could subsequently be transferred to the next plant generation via soil transplantation. Together, our results suggest that small initial variation in soil microbiome composition and functioning can determine the outcomes of plant-pathogen interactions under natural field conditions.
-
Microbial amendments alter protist communities within the soil microbiome
Soil Biology and Biochemistry, 2019Co-Authors: Wu Xiong, Qirong Shen, Sai Guo, Ida Karlsson, George A. Kowalchuk, Zixuan Jiao, Weibing Xun, Stefan GeisenAbstract:Plant-beneficial microbes improve while pathogens reduce plant performance. When introduced in soils, such microbes can induce entire microbiome changes. However, the impact of those microbial introductions on protists – key predators within the soil microbiome – remain unknown. Here, we tracked how soil protists respond to Bacterial (Bacillus and Ralstonia) and fungal (Trichoderma and Fusarium) introductions, with both microbial groups represented by one beneficial and one pathogenic taxon. We found that plant-beneficial Bacillus Bacteria change the protist community structure. This community-shift was likely induced by an increased fungi/Bacteria ratio, supported by a negative correlation of the fungi/Bacteria ratio with the relative abundance of phagotrophic protists across all treatments. Our results indicate that microbial introductions can impact protist communities, thereby altering microbiome-derived multi-functionality.