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1.
PLoS One ; 19(6): e0303578, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38900727

RESUMO

Evaluating archaeobotanical data from over 3.9 million seeds and 124,300 charcoal fragments across 330 archaeological site phases in Southwest Asia, we reconstruct the history of olive and grape cultivation spanning a period of 6,000 years. Combining charcoal and seed data enables investigation into both the production and consumption of olive and grape. The earliest indication for olive and grape cultivation appears in the southern Levant around ca. 5000 BC and 4th millennium BC respectively, although cultivation may have been practiced prior to these dates. Olive and grape cultivation in Southwest Asia was regionally concentrated within the Levant until 600 BC, although there were periodic pushes to the East. Several indications for climate influencing the history of olive and grape cultivation were found, as well as a correlation between periods of high population density and high proportions of olive and grape remains in archaeological sites. While temporal uncertainty prevents a detailed understanding of the causal mechanisms behind these correlations, we suggest that long distance trade in olives, grapes and their associated products was integral to the economic, social, and demographic trajectories of the region.


Assuntos
Arqueologia , Carvão Vegetal , Olea , Sementes , Vitis , Vitis/crescimento & desenvolvimento , Olea/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Humanos , História Antiga , Ásia , Agricultura/história
2.
J Phys Chem B ; 124(47): 10732-10738, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33174757

RESUMO

We have used transient absorption spectroscopy in the UV-visible and X-ray regions to characterize the excited state of CarH, a protein photoreceptor that uses a form of B12, adenosylcobalamin (AdoCbl), to sense light. With visible excitation, a nanosecond-lifetime photoactive excited state is formed with unit quantum yield. The time-resolved X-ray absorption near edge structure difference spectrum of this state demonstrates that the excited state of AdoCbl in CarH undergoes only modest structural expansion around the central cobalt, a behavior similar to that observed for methylcobalamin rather than for AdoCbl free in solution. We propose a new mechanism for CarH photoreactivity involving formation of a triplet excited state. This allows the sensor to operate with high quantum efficiency and without formation of potentially dangerous side products. By stabilizing the excited electronic state, CarH controls reactivity of AdoCbl and enables slow reactions that yield nonreactive products and bypass bond homolysis and reactive radical species formation.


Assuntos
Cobalto
3.
J Phys Chem Lett ; 10(18): 5484-5489, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31483136

RESUMO

Polarized transient X-ray absorption near-edge structure (XANES) was used to probe the excited-state structure of a photostable B12 antivitamin (Coß-2-(2,4-difluorophenyl)-ethynylcobalamin, F2PhEtyCbl). A drop-on-demand delivery system synchronized to the LCLS X-ray free electron laser pulses was implemented and used to measure the XANES difference spectrum 12 ps following excitation, exposing only ∼45 µL of sample. Unlike cyanocobalamin (CNCbl), where the Co-C bond expands 15-20%, the excited state of F2PhEtyCbl is characterized by little change in the Co-C bond, suggesting that the acetylide linkage raises the barrier for expansion of the Co-C bond. In contrast, the lower axial Co-NDMB bond is elongated in the excited state of F2PhEtyCbl by ca. 10% or more, comparable to the 10% elongation observed for Co-NDMB in CNCbl.


Assuntos
Complexos de Coordenação/química , Modelos Moleculares , Vitamina B 12/antagonistas & inibidores , Carbono/química , Cobalto/química , Cinética , Conformação Molecular , Processos Fotoquímicos , Teoria Quântica , Termodinâmica , Raios X
4.
J Phys Chem B ; 123(28): 6042-6048, 2019 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-31290669

RESUMO

We use picosecond time-resolved polarized X-ray absorption near-edge structure (XANES) measurements to probe the structure of the long-lived photoexcited state of methylcobalamin (MeCbl) and the cob(II)alamin photoproduct formed following photoexcitation of adenosylcobalamin (AdoCbl, coenzyme B12). For MeCbl, we used 520 nm excitation and a time delay of 100 ps to avoid the formation of cob(II)alamin. We find only small spectral changes in the equatorial and axial directions, which we interpret as arising from small (<∼0.05 Å) changes in both the equatorial and axial distances. This confirms expectations based on prior UV-visible transient absorption measurements and theoretical simulations. We do not find evidence for the significant elongation of the Co-C bond reported by Subramanian [ J. Phys. Chem. Lett. 2018 , 9 , 1542 - 1546 ] following 400 nm excitation. For AdoCbl, we resolve the difference XANES contributions along three unique molecular axes by exciting with both 540 and 365 nm light, demonstrating that the spectral changes are predominantly polarized along the axial direction, consistent with the loss of axial ligation. These data suggest that the microsecond "recombination product" identified by Subramanian et al. is actually the cob(II)alamin photoproduct that is produced following bond homolysis of MeCbl with 400 nm excitation. Our results highlight the pronounced advantage of using polarization-selective transient X-ray absorption for isolating structural dynamics in systems undergoing atomic displacements that are strongly correlated to the exciting optical polarization.

5.
J Nucl Med ; 44(3): 422-33, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12621010

RESUMO

UNLABELLED: B lymphocyte stimulator (BLyS) protein is a member of the tumor necrosis factor (TNF) superfamily of cytokines that binds to B lineage cells, but not T cells, monocytes, natural killer cells, or granulocytes. BLyS protein binding to B cells is restricted to immunoglobulin-positive cells and is not evident on pro- or pre-B cell populations. This unique binding profile suggests that a radiolabeled form of BLyS protein may be a useful treatment for B cell neoplasias such as B cell lymphoma and multiple myeloma. Here, we report the biodistribution of radiolabeled recombinant human BLyS after intravenous injection into normal mice and mice bearing BCL1 tumor in the spleen or J558 tumor in the subcutaneous space. We also report the use of these data to estimate human dosimetry. METHODS: (125)I-Labeled BLyS protein (50 micro g/kg, 0.185-0.37 MBq per mouse) was injected intravenously into BALB/c mice, and biodistribution was measured by direct counting of radioactivity in dissected tissues and by quantitative whole-body autoradiography (QWBA). RESULTS: The half-life of radiolabeled BLyS protein in blood was approximately 2.7 h in both normal and tumor-bearing mice. The spleen showed the highest uptake of BLyS protein in both normal and tumor-bearing mice, with a maximum concentration (C(max)) of 35-45 percentage injected dose per gram (%ID/g) occurring between 1 and 3 h after injection. In lymph nodes, C(max) was approximately 20 %ID/g in normal and J558 tumor-bearing mice and 8-15 %ID/g in BCL1 tumor-bearing mice. Limited biodistribution data from the J558 tumors showed a C(max) of approximately 15 %ID/g. By contrast, C(max) was only approximately 5 %ID/g for both kidney and liver. QWBA confirmed high radioactivity in spleen, lymph nodes, and stomach contents and low radioactivity in kidney and liver. After 24 h, spleen and lymph nodes were still positive in QWBA images, whereas liver and kidney no longer had observable levels. CONCLUSION: Radiolabeled BLyS showed specific and rapid targeting to lymphoid tissues and B cell tumors in mice. Unlike monoclonal antibodies, which have long plasma half-lives and considerable liver uptake, BLyS has distinct pharmacokinetic and biodistribution properties that may offer advantages compared with antibody-based radioimmunotherapy.


Assuntos
Radioisótopos do Iodo/uso terapêutico , Tecido Linfoide/metabolismo , Linfoma de Células B/radioterapia , Proteínas de Membrana/uso terapêutico , Radioimunoterapia , Fator de Necrose Tumoral alfa/uso terapêutico , Animais , Autorradiografia , Fator Ativador de Células B , Receptor do Fator Ativador de Células B , Feminino , Injeções Intravenosas , Radioisótopos do Iodo/administração & dosagem , Radioisótopos do Iodo/farmacologia , Linfoma de Células B/metabolismo , Proteínas de Membrana/administração & dosagem , Proteínas de Membrana/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Transplante de Neoplasias , Plasmocitoma/metabolismo , Plasmocitoma/radioterapia , Dosagem Radioterapêutica , Receptores do Fator de Necrose Tumoral/análise , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/uso terapêutico , Baço/química , Distribuição Tecidual , Fator de Necrose Tumoral alfa/administração & dosagem , Fator de Necrose Tumoral alfa/farmacologia
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