1
|
Goldsmith M, Siegler J, Green S. Targeted effect of ischemic preconditioning on the gas exchange threshold in healthy males and females. Eur J Appl Physiol 2024:10.1007/s00421-024-05481-8. [PMID: 38642096 DOI: 10.1007/s00421-024-05481-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/29/2024] [Indexed: 04/22/2024]
Abstract
Ischemic preconditioning (IPC) appears to improve exercise performance although there is uncertainty about the intensity dependence of this effect. The present study sought to clarify effects of IPC on physiological responses at and below peak oxygen uptake, including the gas exchange threshold (GET). Ten male and female participants completed five cycling ramp tests (10 W/min) to failure, with the final two tests preceded by either IPC (4 × 5 min 220 mmHg bilateral leg occlusions) or SHAM (20 mmHg), in a randomised crossover design. The rates of O2 uptake ( V ˙ O2), carbon dioxide output ( V ˙ CO2), and expired ventilation ( V ˙ E) were measured at rest and throughout exercise. Exercise data were fitted using several functions to identify GET, two ventilatory thresholds and peak V ˙ O2. IPC increased V ˙ O2 at GET by ~ 9% (IPC: 1.89 ± 0.51 L/min, SHAM: 1.73 ± 0.56 L/min; p = 0.055) and power output at GET by ~ 11% (IPC: 133 ± 36 W, SHAM: 120 ± 39 W; p = 0.022). In addition, peak power output increased by 2.4% following IPC (IPC: 217 ± 50 W, SHAM: 212 ± 51 W; p = 0.052), but there was no significant effect of IPC on peak V ˙ O2 (IPC: 2.87 ± 0.68 L/min, SHAM: 2.84 ± 0.73 L/min; p = 0.60) or the ventilatory thresholds. The present results suggest that IPC improves GET and peak power output but not peak V ˙ O2 during a maximal graded test.
Collapse
Affiliation(s)
- M Goldsmith
- School of Health Sciences, Western Sydney University, Campbelltown Campus Building 20, Sydney, NSW, Australia
| | - J Siegler
- College of Health Solutions, Arizona State University, Phoenix, AZ, USA
| | - S Green
- School of Health Sciences, Western Sydney University, Campbelltown Campus Building 20, Sydney, NSW, Australia.
| |
Collapse
|
2
|
Fox H, Ben-Dor S, Doron-Faigenboim A, Goldsmith M, Klein T, David-Schwartz R. Carbohydrate dynamics in Populus trees under drought: An expression atlas of genes related to sensing, translocation, and metabolism across organs. Physiol Plant 2023; 175:e14001. [PMID: 37882295 DOI: 10.1111/ppl.14001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 07/24/2023] [Accepted: 08/07/2023] [Indexed: 10/27/2023]
Abstract
In trees, nonstructural carbohydrates (NSCs) serve as long-term carbon storage and long-distance carbon transport from source to sink. NSC management in response to drought stress is key to our understanding of drought acclimation. However, the molecular mechanisms underlying these processes remain unclear. By combining a transcriptomic approach with NSC quantification in the leaves, stems, and roots of Populus alba under drought stress, we analyzed genes from 29 gene families related to NSC signaling, translocation, and metabolism. We found starch depletion across organs and accumulation of soluble sugars (SS) in the leaves. Activation of the trehalose-6-phosphate/SNF1-related protein kinase (SnRK1) signaling pathway across organs via the suppression of class I TREHALOSE-PHOSPHATE SYNTHASE (TPS) and the expression of class II TPS genes suggested an active response to drought. The expression of SnRK1α and β subunits, and SUCROSE SYNTHASE6 supported SS accumulation in leaves. The upregulation of active transporters and the downregulation of most passive transporters implied a shift toward active sugar transport and enhanced regulation over partitioning. SS accumulation in vacuoles supports osmoregulation in leaves. The increased expression of sucrose synthesis genes and reduced expression of sucrose degradation genes in the roots did not coincide with sucrose levels, implying local sucrose production for energy. Moreover, the downregulation of invertases in the roots suggests limited sucrose allocation from the aboveground organs. This study provides an expression atlas of NSC-related genes that respond to drought in poplar trees, and can be tested in tree improvement programs for adaptation to drought conditions.
Collapse
Affiliation(s)
- Hagar Fox
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Shifra Ben-Dor
- Department of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Adi Doron-Faigenboim
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Moshe Goldsmith
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tamir Klein
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Rakefet David-Schwartz
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| |
Collapse
|
3
|
Khersonsky O, Goldsmith M, Zaretsky I, Hamer-Rogotner S, Dym O, Unger T, Yona M, Fridmann-Sirkis Y, Fleishman SJ. Stable Mammalian Serum Albumins Designed for Bacterial Expression. J Mol Biol 2023; 435:168191. [PMID: 37385581 DOI: 10.1016/j.jmb.2023.168191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/18/2023] [Accepted: 06/20/2023] [Indexed: 07/01/2023]
Abstract
Albumin is the most abundant protein in the blood serum of mammals and has essential carrier and physiological roles. Albumins are also used in a wide variety of molecular and cellular experiments and in the cultivated meat industry. Despite their importance, however, albumins are challenging for heterologous expression in microbial hosts, likely due to 17 conserved intramolecular disulfide bonds. Therefore, albumins used in research and biotechnological applications either derive from animal serum, despite severe ethical and reproducibility concerns, or from recombinant expression in yeast or rice. We use the PROSS algorithm to stabilize human and bovine serum albumins, finding that all are highly expressed in E. coli. Design accuracy is verified by crystallographic analysis of a human albumin variant with 16 mutations. This albumin variant exhibits ligand binding properties similar to those of the wild type. Remarkably, a design with 73 mutations relative to human albumin exhibits over 40 °C improved stability and is stable beyond the boiling point of water. Our results suggest that proteins with many disulfide bridges have the potential to exhibit extreme stability when subjected to design. The designed albumins may be used to make economical, reproducible, and animal-free reagents for molecular and cell biology. They also open the way to high-throughput screening to study and enhance albumin carrier properties.
Collapse
Affiliation(s)
- Olga Khersonsky
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Moshe Goldsmith
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Irina Zaretsky
- Antibody Engineering Unit, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Shelly Hamer-Rogotner
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Orly Dym
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tamar Unger
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Meital Yona
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yael Fridmann-Sirkis
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sarel J Fleishman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
4
|
Moussa MS, Goldsmith M, Komarova SV. Craniofacial Bones and Teeth in Spacefarers: Systematic Review and Meta-analysis. JDR Clin Trans Res 2023; 8:113-122. [PMID: 35311413 PMCID: PMC10026165 DOI: 10.1177/23800844221084985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION Estimating the risk of dental problems in long-duration space missions to the Moon and Mars is critical for avoiding dental emergencies in an environment that does not support proper treatment. Previous risk estimates were constructed based on the experience in short-duration space missions and isolated environments on Earth. However, previous estimates did not account for potential changes in dental structures due to space travel, even though bone loss is a known problem for long-duration spaceflights. The objective of this study was to systematically analyze the changes in hard tissues of the craniofacial complex during spaceflights. METHODS Comprehensive search of Medline, Embase, Scopus, the NASA Technical Report Server, and other sources identified 1,585 potentially relevant studies. After screening, 32 articles that presented quantitative data for skull in humans (6/32) and for calvariae, mandible, and lower incisors in rats (20/32) and mice (6/32) were selected. RESULTS Skull bone mineral density showed a significant increase in spacefaring humans. In spacefaring rodents, calvariae bone volume to tissue volume (BV/TV) demonstrated a trend toward increasing that did not reach statistical significance, while in mandibles, there was a significant decrease in BV/TV. Dentin thickness and incisor volume of rodent incisors were not significantly different between spaceflight and ground controls. DISCUSSION Our study demonstrates significant knowledge gaps regarding many structures of the craniofacial complex such as the maxilla, molar, premolar, and canine teeth, as well as small sample sizes for the studies of mandible and incisors. Understanding the effects of microgravity on craniofacial structures is important for estimating risks during long-duration spaceflight and for formulating proper protocols to prevent dental emergencies. KNOWLEDGE TRANSFER STATEMENT Avoiding dental emergencies in long-duration spaceflights is critical since this environment does not support proper treatment. Prior risk estimates did not account for changes in dental structures due to space travel. We reviewed and synthesized the literature for changes in craniofacial complex associated with spaceflight. The results of our study will help clinicians and scientists to better prepare to mitigate potential oral health issues in space travelers on long-duration missions.
Collapse
Affiliation(s)
- M S Moussa
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Quebec, Canada
- Shriners Hospital for Children-Canada, Montreal, Quebec, Canada
| | - M Goldsmith
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Quebec, Canada
- Shriners Hospital for Children-Canada, Montreal, Quebec, Canada
| | - S V Komarova
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Quebec, Canada
- Shriners Hospital for Children-Canada, Montreal, Quebec, Canada
| |
Collapse
|
5
|
Kluzek M, Oppenheimer-Shaanan Y, Dadosh T, Morandi MI, Avinoam O, Raanan C, Goldsmith M, Goldberg R, Klein J. Designer Liposomic Nanocarriers Are Effective Biofilm Eradicators. ACS Nano 2022; 16:15792-15804. [PMID: 36018573 PMCID: PMC9620068 DOI: 10.1021/acsnano.2c04232] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 08/22/2022] [Indexed: 06/01/2023]
Abstract
Drug delivery via nanovehicles is successfully employed in several clinical settings, yet bacterial infections, forming microbial communities in the form of biofilms, present a strong challenge to therapeutic treatment due to resistance to conventional antimicrobial therapies. Liposomes can provide a versatile drug-vector strategy for biofilm treatment, but are limited by the need to balance colloidal stability with biofilm penetration. We have discovered a liposomic functionalization strategy, using membrane-embedded moieties of poly[2-(methacryloyloxy)ethyl phosphorylcholine], pMPC, that overcomes this limitation. Such pMPCylation results in liposomic stability equivalent to current functionalization strategies (mostly PEGylation, the present gold-standard), but with strikingly improved cellular uptake and cargo conveyance. Fluorimetry, cryo-electron, and fluorescence microscopies reveal a far-enhanced antibiotic delivery to model Pseudomonas aeruginosa biofilms by pMPC-liposomes, followed by faster cytosolic cargo release, resulting in significantly greater biofilm eradication than either PEGylation or free drug. Moreover, this combination of techniques uncovers the molecular mechanism underlying the enhanced interaction with bacteria, indicating it arises from bridging by divalent ions of the zwitterionic groups on the pMPC moieties to the negatively charged lipopolysaccharide chains emanating from the bacterial membranes. Our results point to pMPCylation as a transformative strategy for liposomal functionalization, leading to next-generation delivery systems for biofilm treatment.
Collapse
Affiliation(s)
- Monika Kluzek
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovot 76100, Israel
| | | | - Tali Dadosh
- Department
of Chemical Research Support, Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Mattia I. Morandi
- Department
of Biomolecular Sciences, Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Ori Avinoam
- Department
of Biomolecular Sciences, Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Calanit Raanan
- Department
of Veterinary Resources, Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Moshe Goldsmith
- Department
of Biomolecular Sciences, Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Ronit Goldberg
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Jacob Klein
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovot 76100, Israel
| |
Collapse
|
6
|
Barber-Zucker S, Mateljak I, Goldsmith M, Kupervaser M, Alcalde M, Fleishman SJ. Designed High-Redox Potential Laccases Exhibit High Functional Diversity. ACS Catal 2022; 12:13164-13173. [PMID: 36366766 PMCID: PMC9638991 DOI: 10.1021/acscatal.2c03006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/29/2022] [Indexed: 11/29/2022]
Abstract
![]()
White-rot fungi secrete an impressive repertoire of high-redox
potential laccases (HRPLs) and peroxidases for efficient oxidation
and utilization of lignin. Laccases are attractive enzymes for the
chemical industry due to their broad substrate range and low environmental
impact. Since expression of functional recombinant HRPLs is challenging,
however, iterative-directed evolution protocols have been applied
to improve their expression, activity, and stability. We implement
a rational, stabilize-and-diversify strategy to two HRPLs that we
could not functionally express. First, we use the PROSS stability-design
algorithm to allow functional expression in yeast. Second, we use
the stabilized enzymes as starting points for FuncLib active-site
design to improve their activity and substrate diversity. Four of
the FuncLib-designed HRPLs and their PROSS progenitor exhibit substantial
diversity in reactivity profiles against high-redox potential substrates,
including lignin monomers. Combinations of 3–4 subtle mutations
that change the polarity, solvation, and sterics of the substrate-oxidation
site result in orders of magnitude changes in reactivity profiles.
These stable and versatile HRPLs are a step toward generating an effective
lignin-degrading consortium of enzymes that can be secreted from yeast.
The stabilize-and-diversify strategy can be applied to other challenging
enzyme families to study and expand the utility of natural enzymes.
Collapse
Affiliation(s)
- Shiran Barber-Zucker
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7600001, Israel
| | - Ivan Mateljak
- Department of Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, Madrid 28049, Spain
- EvoEnzyme S.L., Parque Científico de Madrid, C/Faraday, 7, Campus de Cantoblanco, Madrid 28049, Spain
| | - Moshe Goldsmith
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7600001, Israel
| | - Meital Kupervaser
- Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 7600001, Israel
| | - Miguel Alcalde
- Department of Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, Madrid 28049, Spain
| | - Sarel J. Fleishman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7600001, Israel
| |
Collapse
|
7
|
Goldsmith M, Barad S, Knafo M, Savidor A, Ben-Dor S, Brandis A, Mehlman T, Peleg Y, Albeck S, Dym O, Ben-Zeev E, Barbole RS, Aharoni A, Reich Z. Identification and characterization of the key enzyme in the biosynthesis of the neurotoxin β-ODAP in grass pea. J Biol Chem 2022; 298:101806. [PMID: 35271851 PMCID: PMC9061259 DOI: 10.1016/j.jbc.2022.101806] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 02/27/2022] [Accepted: 02/28/2022] [Indexed: 11/28/2022] Open
Abstract
Grass pea (Lathyrus sativus L.) is a grain legume commonly grown in Asia and Africa for food and forage. It is a highly nutritious and robust crop, capable of surviving both droughts and floods. However, it produces a neurotoxic compound, β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), which can cause a severe neurological disorder when consumed as a primary diet component. While the catalytic activity associated with β-ODAP formation was demonstrated more than 50 years ago, the enzyme responsible for this activity has not been identified. Here, we report on the identity, activity, 3D structure, and phylogenesis of this enzyme—β-ODAP synthase (BOS). We show that BOS belongs to the benzylalcohol O-acetyltransferase, anthocyanin O-hydroxycinnamoyltransferase, anthranilate N-hydroxycinnamoyl/benzoyltransferase, deacetylvindoline 4-O-acetyltransferase superfamily of acyltransferases and is structurally similar to hydroxycinnamoyl transferase. Using molecular docking, we propose a mechanism for its catalytic activity, and using heterologous expression in tobacco leaves (Nicotiana benthamiana), we demonstrate that expression of BOS in the presence of its substrates is sufficient for β-ODAP production in vivo. The identification of BOS may pave the way toward engineering β-ODAP–free grass pea cultivars, which are safe for human and animal consumption.
Collapse
Affiliation(s)
- Moshe Goldsmith
- Dept. of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Shiri Barad
- Dept. of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Maor Knafo
- Dept. of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Alon Savidor
- De Botton Institute for Protein Profiling, The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Shifra Ben-Dor
- Dept. of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Alexander Brandis
- Dept. of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Tevie Mehlman
- Dept. of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yoav Peleg
- Dept. of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Shira Albeck
- Dept. of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Orly Dym
- Dept. of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Efrat Ben-Zeev
- Medicinal Chemistry Unit, The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ranjit S Barbole
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel; Plant Molecular Biology Unit, Division of Biochemical Sciences, Council of Scientific and Industrial Research-National Chemical Laboratory, Pune, 411008, Maharashtra, India
| | - Asaph Aharoni
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ziv Reich
- Dept. of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| |
Collapse
|
8
|
Goldsmith M, Barad S, Peleg Y, Albeck S, Dym O, Brandis A, Mehlman T, Reich Z. The identification and characterization of an oxalyl-CoA synthetase from grass pea (Lathyrus sativus L.). RSC Chem Biol 2022; 3:320-333. [PMID: 35359497 PMCID: PMC8905533 DOI: 10.1039/d1cb00202c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/04/2022] [Indexed: 11/21/2022] Open
Abstract
Oxalic acid is a small metabolite that can be found in many plants in which it serves as protection from herbivores, a chelator of metal ions, a regulator of calcium...
Collapse
Affiliation(s)
- Moshe Goldsmith
- Dept. of Biomolecular Sciences, Weizmann Institute of Science Rehovot 7610001 Israel +972-8-9344118 +972-8-9343278 +972-8-9342982
| | - Shiri Barad
- Dept. of Biomolecular Sciences, Weizmann Institute of Science Rehovot 7610001 Israel +972-8-9344118 +972-8-9343278 +972-8-9342982
| | - Yoav Peleg
- Dept. of Life Science Core Facilities, Weizmann Institute of Science Rehovot 7610001 Israel
| | - Shira Albeck
- Dept. of Life Science Core Facilities, Weizmann Institute of Science Rehovot 7610001 Israel
| | - Orly Dym
- Dept. of Life Science Core Facilities, Weizmann Institute of Science Rehovot 7610001 Israel
| | - Alexander Brandis
- Dept. of Life Science Core Facilities, Weizmann Institute of Science Rehovot 7610001 Israel
| | - Tevie Mehlman
- Dept. of Life Science Core Facilities, Weizmann Institute of Science Rehovot 7610001 Israel
| | - Ziv Reich
- Dept. of Biomolecular Sciences, Weizmann Institute of Science Rehovot 7610001 Israel +972-8-9344118 +972-8-9343278 +972-8-9342982
| |
Collapse
|
9
|
Goldsmith M, Ashani Y. Corrigendum to “Catalytic bioscavengers as countermeasures against organophosphate nerve agents”, [Chem. Biol. Interact. 292 (2018) 50–64]. Chem Biol Interact 2018; 293:152. [DOI: 10.1016/j.cbi.2018.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
10
|
Goldenzweig A, Goldsmith M, Hill SE, Gertman O, Laurino P, Ashani Y, Dym O, Unger T, Albeck S, Prilusky J, Lieberman RL, Aharoni A, Silman I, Sussman JL, Tawfik DS, Fleishman SJ. Automated Structure- and Sequence-Based Design of Proteins for High Bacterial Expression and Stability. Mol Cell 2018; 70:380. [PMID: 29677494 PMCID: PMC5919778 DOI: 10.1016/j.molcel.2018.03.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
11
|
Pham M, Goldsmith M, Fuleihan R, Sullivan K, Cunningham-Rundles C. OR064 Ocular manifestations in primary immunodeficiency (PID) patients within the us immunodeficiency network (USIDNET) registry. Ann Allergy Asthma Immunol 2017. [DOI: 10.1016/j.anai.2017.08.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
12
|
Goldsmith M, Tawfik DS. Enzyme engineering: reaching the maximal catalytic efficiency peak. Curr Opin Struct Biol 2017; 47:140-150. [PMID: 29035814 DOI: 10.1016/j.sbi.2017.09.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/04/2017] [Accepted: 09/20/2017] [Indexed: 01/01/2023]
Abstract
The practical need for highly efficient enzymes presents new challenges in enzyme engineering, in particular, the need to improve catalytic turnover (kcat) or efficiency (kcat/KM) by several orders of magnitude. However, optimizing catalysis demands navigation through complex and rugged fitness landscapes, with optimization trajectories often leading to strong diminishing returns and dead-ends. When no further improvements are observed in library screens or selections, it remains unclear whether the maximal catalytic efficiency of the enzyme (the catalytic 'fitness peak') has been reached; or perhaps, an alternative combination of mutations exists that could yield additional improvements. Here, we discuss fundamental aspects of the process of catalytic optimization, and offer practical solutions with respect to overcoming optimization plateaus.
Collapse
Affiliation(s)
- Moshe Goldsmith
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
| | - Dan S Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
13
|
Goldsmith M. On the P-Wave Strength Functions of Thorium-232 and Uranium-238. NUCL SCI ENG 2017. [DOI: 10.13182/nse73-a23313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- M. Goldsmith
- Bettis Atomic Power Laboratory West Mifflin, Pennsylvania 15122
| |
Collapse
|
14
|
Affiliation(s)
- M. Goldsmith
- Westinghouse Electric Corporation, Bettis Atomic Power Laboratory, West Mifflin, Pennsylvania 15122
| | - J. J. Ullo
- Westinghouse Electric Corporation, Bettis Atomic Power Laboratory, West Mifflin, Pennsylvania 15122
| |
Collapse
|
15
|
Ullo JJ, Goldsmith M. Monte Carlo Analysis of Direct Measurements of the Fission Neutron Yield Per Absorption by Uranium-233 and Uranium-235 of Monochromatic Neutrons. NUCL SCI ENG 2017. [DOI: 10.13182/nse76-a26881] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J. J. Ullo
- Westinghouse Electric Corporation, Bettis Atomic Power Laboratory, West Mifflin, Pennsylvania 15122
| | - M. Goldsmith
- Westinghouse Electric Corporation, Bettis Atomic Power Laboratory, West Mifflin, Pennsylvania 15122
| |
Collapse
|
16
|
Goldsmith M, Aggarwal N, Ashani Y, Jubran H, Greisen PJ, Ovchinnikov S, Leader H, Baker D, Sussman JL, Goldenzweig A, Fleishman SJ, Tawfik DS. Overcoming an optimization plateau in the directed evolution of highly efficient nerve agent bioscavengers. Protein Eng Des Sel 2017; 30:333-345. [DOI: 10.1093/protein/gzx003] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/10/2017] [Indexed: 11/13/2022] Open
|
17
|
Goldsmith M, Ashani Y, Margalit R, Nyska A, Mirelman D, Tawfik DS. A new post-intoxication treatment of paraoxon and parathion poisonings using an evolved PON1 variant and recombinant GOT1. Chem Biol Interact 2016; 259:242-251. [DOI: 10.1016/j.cbi.2016.05.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 05/04/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
|
18
|
Wille T, Neumaier K, Koller M, Ehinger C, Aggarwal N, Ashani Y, Goldsmith M, Sussman JL, Tawfik DS, Thiermann H, Worek F. Single treatment of VX poisoned guinea pigs with the phosphotriesterase mutant C23AL: Intraosseous versus intravenous injection. Toxicol Lett 2016; 258:198-206. [DOI: 10.1016/j.toxlet.2016.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 06/27/2016] [Accepted: 07/06/2016] [Indexed: 02/09/2023]
|
19
|
Goldenzweig A, Goldsmith M, Hill SE, Gertman O, Laurino P, Ashani Y, Dym O, Unger T, Albeck S, Prilusky J, Lieberman RL, Aharoni A, Silman I, Sussman JL, Tawfik DS, Fleishman SJ. Automated Structure- and Sequence-Based Design of Proteins for High Bacterial Expression and Stability. Mol Cell 2016; 63:337-346. [PMID: 27425410 PMCID: PMC4961223 DOI: 10.1016/j.molcel.2016.06.012] [Citation(s) in RCA: 277] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/18/2016] [Accepted: 06/07/2016] [Indexed: 12/28/2022]
Abstract
Upon heterologous overexpression, many proteins misfold or aggregate, thus resulting in low functional yields. Human acetylcholinesterase (hAChE), an enzyme mediating synaptic transmission, is a typical case of a human protein that necessitates mammalian systems to obtain functional expression. We developed a computational strategy and designed an AChE variant bearing 51 mutations that improved core packing, surface polarity, and backbone rigidity. This variant expressed at ∼2,000-fold higher levels in E. coli compared to wild-type hAChE and exhibited 20°C higher thermostability with no change in enzymatic properties or in the active-site configuration as determined by crystallography. To demonstrate broad utility, we similarly designed four other human and bacterial proteins. Testing at most three designs per protein, we obtained enhanced stability and/or higher yields of soluble and active protein in E. coli. Our algorithm requires only a 3D structure and several dozen sequences of naturally occurring homologs, and is available at http://pross.weizmann.ac.il. A new computational method is used to stabilize five recalcitrant proteins Designed variants show higher expression and stability with unmodified function A designed human acetylcholinesterase variant expresses solubly in bacteria The method is fully automated and implemented on a webserver
Collapse
Affiliation(s)
- Adi Goldenzweig
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Moshe Goldsmith
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Shannon E Hill
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
| | - Or Gertman
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
| | - Paola Laurino
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yacov Ashani
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel; Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Orly Dym
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tamar Unger
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Shira Albeck
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jaime Prilusky
- Bioinformatics & Biological Computing Unit, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
| | - Amir Aharoni
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
| | - Israel Silman
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Joel L Sussman
- Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Dan S Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Sarel J Fleishman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
20
|
Ashani Y, Leader H, Aggarwal N, Silman I, Worek F, Sussman JL, Goldsmith M. In vitro evaluation of the catalytic activity of paraoxonases and phosphotriesterases predicts the enzyme circulatory levels required for in vivo protection against organophosphate intoxications. Chem Biol Interact 2016; 259:252-256. [PMID: 27163850 DOI: 10.1016/j.cbi.2016.04.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/19/2016] [Accepted: 04/28/2016] [Indexed: 11/26/2022]
Abstract
Catalytic scavengers of organophosphates (OPs) are considered very promising antidote candidates for preventing the adverse effects of OP intoxication as stand alone treatments. This study aimed at correlating the in-vivo catalytic efficiency ((kcat/KM)[Enzyme]pl), established prior to the OP challenge, with the severity of symptoms and survival rates of intoxicated animals. The major objective was to apply a theoretical approach to estimate a lower limit for (kcat/KM)[Enzyme]pl that will be adequate for establishing the desired kcat/KM value and plasma concentration of efficacious catalytic bioscavengers. Published data sets by our group and others, from in vivo protection experiments executed in the absence of any supportive medicine, were analyzed. The kcat/KM values of eight OP hydrolyzing enzymes and their plasma concentrations in four species exposed to OPs via s.c., i.m. and oral gavage, were analyzed. Our results show that regardless of the OP type and the animal species employed, sign-free animals were observed following bioscavenger treatment provided the theoretically estimated time period required to detoxify 96% of the OP (t96%) in vivo was ≤10 s. This, for example, can be achieved by an enzyme with kcat/KM = 5 × 107 M-1 min-1 and a plasma concentration of 0.4 μM ((kcat/KM)[Enzyme]pl = 20 min-1). Experiments in which animals were intoxicated by i.v. OP injections did not always conform to this rule, and in some cases resulted in high mortality rates. We suggest that in vivo evaluation of catalytic scavengers should avoid the unrealistic bolus i.v. route of OP exposure.
Collapse
Affiliation(s)
- Yacov Ashani
- Dept. of Structural Biology, The Weizmann Institute of Science, Rehovot, Israel.
| | - Haim Leader
- Dept. of Materials and Interfaces, The Weizmann Institute of Science, Rehovot, Israel.
| | - Nidhi Aggarwal
- Dept. of Structural Biology, The Weizmann Institute of Science, Rehovot, Israel.
| | - Israel Silman
- Dept. of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel.
| | - Franz Worek
- The Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany.
| | - Joel L Sussman
- Dept. of Materials and Interfaces, The Weizmann Institute of Science, Rehovot, Israel.
| | - Moshe Goldsmith
- Dept. of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
21
|
Goldsmith M, Eckstein S, Ashani Y, Greisen P, Leader H, Sussman JL, Aggarwal N, Ovchinnikov S, Tawfik DS, Baker D, Thiermann H, Worek F. Catalytic efficiencies of directly evolved phosphotriesterase variants with structurally different organophosphorus compounds in vitro. Arch Toxicol 2015; 90:2711-2724. [DOI: 10.1007/s00204-015-1626-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/22/2015] [Indexed: 11/29/2022]
|
22
|
Worek F, Seeger T, Goldsmith M, Ashani Y, Leader H, Sussman JS, Tawfik D, Thiermann H, Wille T. Efficacy of the rePON1 mutant IIG1 to prevent cyclosarin toxicity in vivo and to detoxify structurally different nerve agents in vitro. Arch Toxicol 2014; 88:1257-66. [DOI: 10.1007/s00204-014-1204-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/16/2014] [Indexed: 01/09/2023]
|
23
|
Rockah-Shmuel L, Tawfik DS, Goldsmith M. Generating targeted libraries by the combinatorial incorporation of synthetic oligonucleotides during gene shuffling (ISOR). Methods Mol Biol 2014; 1179:129-137. [PMID: 25055774 DOI: 10.1007/978-1-4939-1053-3_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Protein engineering by directed evolution relies on the use of libraries enriched with beneficial variants. Such libraries should explore large mutational diversities while avoiding high loads of deleterious mutations. Here we describe a simple protocol for incorporating synthetic oligonucleotides that encode designed, site-specific mutations by assembly PCR. This protocol enables a researcher to "hedge the bets," namely, to explore a large number of potentially beneficial mutations in a combinatorial manner such that individual library variants carry a limited number of mutations.
Collapse
Affiliation(s)
- Liat Rockah-Shmuel
- Department of Biological Chemistry, Weizmann Institute of Science, 234 Herzel st., Rehovot, 76100, Israel
| | | | | |
Collapse
|
24
|
|
25
|
Goldsmith M, Ashani Y, Simo Y, Ben-David M, Leader H, Silman I, Sussman JL, Tawfik DS. Evolved stereoselective hydrolases for broad-spectrum G-type nerve agent detoxification. ACTA ACUST UNITED AC 2012; 19:456-66. [PMID: 22520752 DOI: 10.1016/j.chembiol.2012.01.017] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 01/16/2012] [Accepted: 01/18/2012] [Indexed: 11/17/2022]
Abstract
A preferred strategy for preventing nerve agents intoxication is catalytic scavenging by enzymes that hydrolyze them before they reach their targets. Using directed evolution, we simultaneously enhanced the activity of a previously described serum paraoxonase 1 (PON1) variant for hydrolysis of the toxic S(P) isomers of the most threatening G-type nerve agents. The evolved variants show ≤340-fold increased rates and catalytic efficiencies of 0.2-5 × 10(7) M(-1) min(-1). Our selection for prevention of acetylcholinesterase inhibition also resulted in the complete reversion of PON1's stereospecificity, from an enantiomeric ratio (E) < 6.3 × 10(-4) in favor of the R(P) isomer of a cyclosarin analog in wild-type PON1, to E > 2,500 for the S(P) isomer in an evolved variant. Given their ability to hydrolyze G-agents, these evolved variants may serve as broad-range G-agent prophylactics.
Collapse
Affiliation(s)
- Moshe Goldsmith
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Baruch O, Kimchi R, Goldsmith M. Object Recognition is an Interactive Iterative Process. J Vis 2012. [DOI: 10.1167/12.9.270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
27
|
Goldsmith M, Tawfik DS. Directed enzyme evolution: beyond the low-hanging fruit. Curr Opin Struct Biol 2012; 22:406-12. [DOI: 10.1016/j.sbi.2012.03.010] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/14/2012] [Accepted: 03/14/2012] [Indexed: 12/26/2022]
|
28
|
Baruch O, Kimchi R, Goldsmith M. Attention is Directed to Distinguishing Features During Object Recognition. J Vis 2011. [DOI: 10.1167/11.11.866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
29
|
Ashani Y, Goldsmith M, Leader H, Silman I, Sussman JL, Tawfik DS. In vitro detoxification of cyclosarin in human blood pre-incubated ex vivo with recombinant serum paraoxonases. Toxicol Lett 2011; 206:24-8. [PMID: 21807078 DOI: 10.1016/j.toxlet.2011.07.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/18/2011] [Accepted: 07/15/2011] [Indexed: 11/24/2022]
Abstract
An ex vivo protocol was developed to assay the antidotal capacity of rePON1 variants to protect endogenous acetylcholinesterase and butyrylcholinesterase in human whole blood against OP nerve agents. This protocol permitted us to address the relationship between blood rePON1 concentrations, their kinetic parameters, and the level of protection conferred by rePON1 on the cholinesterases in human blood, following a challenge with cyclosarin (GF). The experimental data thus obtained were in good agreement with the predicted percent residual activities of blood cholinesterases calculated on the basis of the rate constants for inhibition of human acetylcholinesterase and butyrylcholinesterase by GF, the concentration of the particular rePON1 variant, and its k(cat)/K(m) value for GF. This protocol thus provides a rapid and reliable ex vivo screening tool for identification of rePON1 bioscavenger candidates suitable for protection of humans against organophosphorus-based toxicants. The results also permitted the refinement of a mathematical model for estimating the efficacious dose of rePON1s variants required for prophylaxis in humans.
Collapse
Affiliation(s)
- Yacov Ashani
- Department of Structural Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | | | | | | | |
Collapse
|
30
|
Gupta RD, Goldsmith M, Ashani Y, Simo Y, Mullokandov G, Bar H, Ben-David M, Leader H, Margalit R, Silman I, Sussman JL, Tawfik DS. Directed evolution of hydrolases for prevention of G-type nerve agent intoxication. Nat Chem Biol 2011; 7:120-5. [DOI: 10.1038/nchembio.510] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 11/22/2010] [Indexed: 11/09/2022]
|
31
|
Ashani Y, Gupta RD, Goldsmith M, Silman I, Sussman JL, Tawfik DS, Leader H. Stereo-specific synthesis of analogs of nerve agents and their utilization for selection and characterization of paraoxonase (PON1) catalytic scavengers. Chem Biol Interact 2010; 187:362-9. [PMID: 20303930 DOI: 10.1016/j.cbi.2010.02.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 02/11/2010] [Accepted: 02/23/2010] [Indexed: 10/19/2022]
Abstract
Fluorogenic organophosphate inhibitors of acetylcholinesterase (AChE) homologous in structure to nerve agents provide useful probes for high throughput screening of mammalian paraoxonase (PON1) libraries generated by directed evolution of an engineered PON1 variant with wild-type like specificity (rePON1). Wt PON1 and rePON1 hydrolyze preferentially the less-toxic R(P) enantiomers of nerve agents and of their fluorogenic surrogates containing the fluorescent leaving group, 3-cyano-7-hydroxy-4-methylcoumarin (CHMC). To increase the sensitivity and reliability of the screening protocol so as to directly select rePON1 clones displaying stereo-preference towards the toxic S(P) enantiomer, and to determine accurately K(m) and k(cat) values for the individual isomers, two approaches were used to obtain the corresponding S(P) and R(P) isomers: (a) stereo-specific synthesis of the O-ethyl, O-n-propyl, and O-i-propyl analogs and (b) enzymic resolution of a racemic mixture of O-cyclohexyl methylphosphonylated CHMC. The configurational assignments of the S(P) and R(P) isomers, as well as their optical purity, were established by X-ray diffraction, reaction with sodium fluoride, hydrolysis by selected rePON1 variants, and inhibition of AChE. The S(P) configuration of the tested surrogates was established for the enantiomer with the more potent anti-AChE activity, with S(P)/R(P) inhibition ratios of 10-100, whereas the R(P) isomers of the O-ethyl and O-n-propyl were hydrolyzed by wt rePON1 about 600- and 70-fold faster, respectively, than the S(P) counterpart. Wt rePON1-induced R(P)/S(P) hydrolysis ratios for the O-cyclohexyl and O-i-propyl analogs are estimated to be >>1000. The various S(P) enantiomers of O-alkyl-methylphosphonyl esters of CHMC provide suitable ligands for screening rePON1 libraries, and can expedite identification of variants with enhanced catalytic proficiency towards the toxic nerve agents.
Collapse
Affiliation(s)
- Y Ashani
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | | | | | | | | | |
Collapse
|
32
|
Izhar L, Goldsmith M, Dahan R, Geacintov N, Lloyd RG, Livneh Z. Analysis of strand transfer and template switching mechanisms of DNA gap repair by homologous recombination in Escherichia coli: predominance of strand transfer. J Mol Biol 2008; 381:803-9. [PMID: 18585391 DOI: 10.1016/j.jmb.2008.06.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 06/04/2008] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
Abstract
Daughter strand gaps formed upon interruption of replication at DNA lesions in Escherichia coli can be repaired by either translesion DNA synthesis or homologous recombination (HR) repair. Using a plasmid-based assay system that enables discrimination between strand transfer and template switching (information copying) modes of HR gap repair, we found that approximately 80% of strand gaps were repaired by physical strand transfer from the donor, whereas approximately 20% appear to be repaired by template switching. HR gap repair operated on both small and bulky lesions and largely depended on RecA and RecF but not on the RecBCD nuclease. In addition, we found that HR was mildly reduced in cells lacking the RuvABC and RecG proteins involved in resolution of Holliday junctions. These results, obtained for the first time under conditions that detect the two HR gap repair mechanisms, provide in vivo high-resolution molecular evidence for the predominance of the strand transfer mechanism in HR gap repair. A small but significant portion of HR gap repair appears to occur via a template switching mechanism.
Collapse
Affiliation(s)
- Lior Izhar
- Department of Biological Chemistry, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | | | | | | | |
Collapse
|
33
|
Damadian R, Minkoff L, Goldsmith M. Whole-body nuclear magnetic resonance scanning: n.m.r. studies of tumour cells. Ciba Found Symp 2008:131-41. [PMID: 259494 DOI: 10.1002/9780470720493.ch9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A technique, field-foxusing nuclear magnetic resonance (n.m.r.) spectroscopy (FONAR), is described for doing n.m.r. scans in large samples. The method utilizes a shaped d.c. magnetic field that confines the n.m.r. signal-producing region of the sample to a small volume called the resonance aperture. The aperture contains the required values of the Ho field to fully bracket the band of the r.f. pulse. The magnet system and r.f. pick-up coil that achieved the first human n.m.r. scan are discussed.
Collapse
|
34
|
Abstract
This article describes a set of standard control experiments for the authentication of new protein variants isolated through library selection and site-directed mutagenesis. These controls are specifically designed to rule out artifacts derived from 'double transformants' -- i.e. cells transformed with, or infected by, two different plasmids simultaneously. These seem to have been the source of past artifacts and, as demonstrated here, are far more common than generally recognized. By following standard protocols for cloning, plasmid isolation, subcloning, in combination with functional assays, the presence of such artifacts can be ruled out. This protocol needs to be applied for any new variant isolated from heterogeneous gene repertoires, and in particular for variants isolated by selection for either enzymatic activity, or binding.
Collapse
Affiliation(s)
- Moshe Goldsmith
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | | | | | | |
Collapse
|
35
|
Avkin S, Goldsmith M, Velasco-Miguel S, Geacintov N, Friedberg EC, Livneh Z. Quantitative analysis of translesion DNA synthesis across a benzo[a]pyrene-guanine adduct in mammalian cells: the role of DNA polymerase kappa. J Biol Chem 2004; 279:53298-305. [PMID: 15475561 DOI: 10.1074/jbc.m409155200] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Replication across unrepaired DNA lesions in mammalian cells is effected primarily by specialized, low fidelity DNA polymerases. We studied translesion DNA synthesis (TLS) across a benzo[a]pyrene-guanine (BP-G) adduct, a major mutagenic DNA lesion generated by tobacco smoke. This was done using a quantitative assay that measures TLS indirectly, by measuring the recovery of gapped plasmids transfected into cultured mammalian cells. Analysis of PolK(+/+) mouse embryo fibroblasts (MEFs) showed that TLS across the BP-G adduct occurred with an efficiency of 48 +/- 4%, which is an order of magnitude higher than in Escherichia coli. In PolK(-/-) MEFs, bypass was 16 +/- 1%, suggesting that at least two-thirds of the BP-G adducts in MEFs were bypassed exclusively by polymerase kappa (polkappa). In contrast, poleta was not required for bypass across BP-G in a human XP-V cell line. Analysis of misinsertion specificity across BP-G revealed that bypass was more error-prone in MEFs lacking polkappa. Expression of polkappa from a plasmid introduced into PolK(-/-) MEFs restored both the extent and fidelity of bypass across BP-G. Polkappa was not required for bypass of a synthetic abasic site. In vitro analysis demonstrated efficient bypass across BP-G by both polkappa and poleta, suggesting that the biological role of polkappa in TLS across BP-G is due to regulation of TLS and not due to an exclusive ability to bypass this lesion. These results indicate that BP-G is bypassed in mammalian cells with relatively high efficiency and that polkappa bypasses BP-G in vivo with higher efficiency and higher accuracy than other DNA polymerases.
Collapse
Affiliation(s)
- Sharon Avkin
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | | | | | | | |
Collapse
|
36
|
|
37
|
Koriat A, Goldsmith M, Schneider W, Nakash-Dura M. The credibility of children's testimony: can children control the accuracy of their memory reports? J Exp Child Psychol 2001; 79:405-37. [PMID: 11511131 DOI: 10.1006/jecp.2000.2612] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In previous work with adults (A. Koriat & M. Goldsmith, 1994, 1996c), it was shown that people can enhance the accuracy of their testimony substantially when they (a) are effective in monitoring the correctness of their answers, (b) are free to control their reporting accordingly (i.e., to decide which pieces of information to volunteer and which to withhold), and (c) are given incentives for accurate reporting. A theoretical model was developed, which specifies the critical role of metacognitive monitoring and control processes in mediating free-report memory accuracy. The present study applies that model to examine the strategic regulation of memory accuracy by children. Three experiments indicate that both younger (ages 7 to 9) and older (ages 10 to 12) children can enhance the accuracy of their testimony by screening out wrong answers under free-report conditions but suggest a developmental trend in the level of memory accuracy that is thereby achieved. The implications of the results for the dependability of children's testimony in legal settings are discussed.
Collapse
Affiliation(s)
- A Koriat
- Institute of Information Processing and Decision Making, University of Haifa, Haifa, Israel.
| | | | | | | |
Collapse
|
38
|
Schiffer CA, Anderson KC, Bennett CL, Bernstein S, Elting LS, Goldsmith M, Goldstein M, Hume H, McCullough JJ, McIntyre RE, Powell BL, Rainey JM, Rowley SD, Rebulla P, Troner MB, Wagnon AH. Platelet transfusion for patients with cancer: clinical practice guidelines of the American Society of Clinical Oncology. J Clin Oncol 2001; 19:1519-38. [PMID: 11230498 DOI: 10.1200/jco.2001.19.5.1519] [Citation(s) in RCA: 453] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE To determine the most effective, evidence-based approach to the use of platelet transfusions in patients with cancer. OUTCOMES Outcomes of interest included prevention of morbidity and mortality from hemorrhage, effects on survival, quality of life, toxicity reduction, and cost-effectiveness. EVIDENCE A complete MedLine search was performed of the past 20 years of the medical literature. Keywords included platelet transfusion, alloimmunization, hemorrhage, threshold and thrombocytopenia. The search was broadened by articles from the bibliographies of selected articles. VALUES Levels of evidence and guideline grades were rated by a standard process. More weight was given to studies that tested a hypothesis directly related to one of the primary outcomes in a randomized design. BENEFITS/HARMS/COST: The possible consequences of different approaches to the use of platelet transfusion were considered in evaluating a preference for one or another technique producing similar outcomes. Cost alone was not a determining factor. RECOMMENDATIONS Appendix A summarizes the recommendations concerning the choice of particular platelet preparations, the use of prophylactic platelet transfusions, indications for transfusion in selected clinical situations, and the diagnosis, prevention, and management of refractoriness to platelet transfusion. VALIDATION Five outside reviewers, the ASCO Health Services Research Committee, and the ASCO Board reviewed this document. SPONSOR American Society of Clinical Oncology
Collapse
Affiliation(s)
- C A Schiffer
- Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit MI, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
There has been unprecedented interest in recent years in questions pertaining to accuracy and distortion in memory. This interest, catalyzed in part by real-life problems, marks a significant departure from the quantity-oriented approach that has characterized much of traditional memory research. We outline a correspondence metaphor of memory underlying accuracy-oriented research, and show how the features of this metaphor are manifested across the disparate bodies of research reviewed here. These include work in the Gestalt tradition, spatial memory, memory for gist, schema theory, source monitoring, fluency misattributions, false recall and recognition, postevent misinformation, false memories, eyewitness research, and autobiographical memory. In examining the dynamics of memory accuracy, we highlight the importance of metacognitive monitoring and control processes. We end by discussing some of the methodological, theoretical, and metatheoretical issues inherent in accuracy-oriented research, attempting to prepare the groundwork for a more coherent psychology of memory accuracy.
Collapse
Affiliation(s)
- A Koriat
- Department of Psychology, University of Haifa, Israel.
| | | | | |
Collapse
|
40
|
Goldsmith M, Sarov-Blat L, Livneh Z. Plasmid-encoded MucB protein is a DNA polymerase (pol RI) specialized for lesion bypass in the presence of MucA', RecA, and SSB. Proc Natl Acad Sci U S A 2000; 97:11227-31. [PMID: 11016960 PMCID: PMC17182 DOI: 10.1073/pnas.200361997] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Replication through damaged sites in DNA requires in Escherichia coli the SOS stress-inducible DNA polymerase V (UmuC), which is specialized for lesion bypass. Homologs of the umuC gene were found on native conjugative plasmids, which often carry multiple antibiotic-resistant genes. MucB is a UmuC homolog present on plasmid R46, and its variant plasmid pKM101 has been introduced into Salmonella strains for use in the Ames test for mutagens. Using a translesion replication assay based on a gapped plasmid carrying a site-specific synthetic abasic site in the single-stranded DNA region, we show that MucB is a DNA polymerase, termed pol RI, which is specialized for lesion bypass. The activity of pol RI requires the plasmid-encoded MucA' protein and the E. coli RecA and single-strand DNA binding proteins. Elimination of any of the proteins from the reaction abolished lesion bypass and polymerase activity. The unprocessed MucA could not substitute for MucA' in the bypass reaction. The presence of a lesion bypass DNA polymerase on a native conjugative plasmid, which has a broad host range specificity and carries multiple antibiotic-resistant genes, raises the possibility that mutagenesis caused by pol RI plays a role in the spreading of antibiotic resistance among bacterial pathogens.
Collapse
Affiliation(s)
- M Goldsmith
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | |
Collapse
|
41
|
Vandier D, Rixe O, Besnard F, Kim M, Rikiyama T, Goldsmith M, Brenner M, Gouyette A, Cowan KH. Inhibition of glioma cells in vitro and in vivo using a recombinant adenoviral vector containing an astrocyte-specific promoter. Cancer Gene Ther 2000; 7:1120-6. [PMID: 10975672 DOI: 10.1038/sj.cgt.7700211] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Gene therapy using the herpes simplex virus thymidine kinase (HSV-TK) gene in combination with the drug ganciclovir (GCV) is a promising approach for the treatment of cancer-inducing gliomas, a tumor with a poor prognosis. In an attempt to limit the toxic effects on normal tissues, we constructed a recombinant adenoviral vector, Adgfa2TK, in which the HSV-TK gene is driven by the promoter for the gene encoding glial fibrillary acidic protein, an intermediate filament protein expressed primarily in astrocytes. Infection by Adgfa2TK of a glial cell line (C6) and a non-glial cell line (MDA-MB-231) revealed markedly increased expression of HSV-TK in glial cells as determined by Western blot. In comparison, high HSV-TK protein levels were produced in both cell lines after infection with a control virus, AdCMVTK, in which the constitutive cytomegalovirus viral promoter was used to direct HSV-TK expression. Infection of two glial cell lines (C6, U251) and two non-glial cell lines (HepG2, MDA-MB-231) with Adgfa2TK followed by GCV treatment revealed high toxicity in glial cell lines (50% growth inhibitory concentration: <2 microg/mL of GCV) with little or no toxicity (50% growth inhibitory concentration: >75 microg/mL) in the non-glial cell lines. In vivo, injection of Adgfa2TK into C6 tumors grown in nude mice followed by intraperitoneal GCV treatment significantly repressed tumor growth compared with the controls. Adgfa2TK may be useful for directing expression of the HSV-TK gene to gliomas.
Collapse
Affiliation(s)
- D Vandier
- Medicine Branch, National Cancer Institute, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Reilly L, Carlisle J, Mikan K, Goldsmith M. External review for promotion and tenure in schools of nursing. Nurse Educ Today 1996; 16:368-372. [PMID: 9025527 DOI: 10.1016/s0260-6917(96)80011-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To obtain information about external review for tenure and/or promotion, the faculty affairs committee in a large nursing program located in the southeastern United States conducted a survey among programs that award a doctoral degree in nursing. Research questions focused on general tenure and promotion policies, policies and procedures regarding the use of external review, and perceived advantages and disadvantages of external review. A 22-item survey was sent to 53 institutions with a total of 34 usable surveys being returned. Findings revealed that a majority of the schools used external review, especially for tenure decisions and promotion to the associate and professor rank. Promotion and tenure criteria from individual schools were usually sent to reviewers along with the candidates' curriculum vitae and manuscripts. Candidates usually participated in the selection of external reviewers, but contact with reviewers was usually instituted by the administration within the institution. It was also felt that the advantage of external review far outweighed any disadvantages.
Collapse
Affiliation(s)
- L Reilly
- University of Alabama School of Nursing, Birmingham 35294-1210, USA
| | | | | | | |
Collapse
|
43
|
Gerbino PP, Goldsmith M, Kenney JT, Lindley C, Nolte J, Quan W, Reich PR. Antiemetic therapy in managed care oncology: roundtable discussion. Med Interface 1996; Suppl C:16-35. [PMID: 10161507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Few diagnoses are feared more by patients than cancer. In addition to the life-threatening nature of many cancers, the spectre of very difficult the treatment provides patients with little or no level of comfort. However, recent advances in the treatment of the side effects of cancer chemotherapy are helping to change these attitudes. On April 4, 1996, a panel of experts was convened to discuss these issues and how they affect MCOs.
Collapse
|
44
|
Abstract
When people are allowed freedom to volunteer or withhold information, they can enhance the accuracy of their memory reports substantially relative to forced-report performance. A theoretical framework addressing the strategic regulation of memory reporting is put forward that delineates the mediating role of metamemorial monitoring and control processes. Although the enhancement of memory accuracy is generally accompanied by a reduction in memory quantity, experimental and simulation results indicate that both of these effects depend critically on (a) accuracy incentive and (b) monitoring effectiveness. The results are discussed with regard to the contribution of meta-memory processes to memory performance, and a general methodology is proposed that incorporates these processes into the assessment of memory-accuracy and memory-quantity performance.
Collapse
Affiliation(s)
- A Koriat
- Department of Psychology, University of Haifa, Israel.
| | | |
Collapse
|
45
|
Abernethy K, Bradley BE, Dankmyer B, Connerton P, England MJ, Goldsmith M, Mortimer J, Maher WB, Halvorson GC, Simmons HE, Goldberg MA, Rahill D. Predicting progress and pitfalls in 1996. Discussion. Bus Health 1996; 14:16-7, 20, 22-4. [PMID: 10156379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
46
|
Abstract
Microtubules (MTs) interact with force-generating proteins to generate a variety of intracellular movements, including intracellular particle transport, ciliary-flagellar beating, and chromosome-spindle movements during mitosis-meiosis. Relatively little is known about the mechanics of these motor-MT interactions, in part because the motor binding domains of the MT and the corresponding MT binding domains of the motor have not been well characterized. Using a flagellar motility assay, we report that the MT subunits, alpha- and beta-tubulin, each contain a dynein binding domain located near the C-termini of their respective tubulin subunits. Blocking either alpha- or beta-tubulin binding domains of dynein attenuates motility in demembranated sea urchin sperm up to 50%. Interestingly, blocking both alpha- and beta-tubulin binding domains on dynein produces much greater decreases in motility. These data suggest that flagellar dynein binds to both subunits of the MT polymer, alpha- and beta-tublin. In addition, the two subunits appear to contribute equivalent, but functionally separate, roles to flagellar motility.
Collapse
Affiliation(s)
- M Goldsmith
- Department of Anatomy and Cell Biology, University of Toronto, ON, Canada
| | | | | |
Collapse
|
47
|
Goldsmith M, Kilty J, Leebov W. At Albert Einstein, alignment of staff and MD performance with values is business strategy. Strateg Healthc Excell 1995; 8:9-12. [PMID: 10141750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- M Goldsmith
- Albert Einstein Healthcare Network, Philadelphia, USA
| | | | | |
Collapse
|
48
|
Koriat A, Goldsmith M. Memory in naturalistic and laboratory contexts: distinguishing the accuracy-oriented and quantity-oriented approaches to memory assessment. J Exp Psychol Gen 1994; 123:297-315. [PMID: 7931094 DOI: 10.1037/0096-3445.123.3.297] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A distinction is drawn between the quantity-oriented approach to memory that has dominated traditional laboratory research, and the accuracy-oriented approach that is emerging in the study of everyday memory. This distinction is shown to underlie some troubling confusions in the interpretation of empirical findings. In particular, the recall-recognition paradox, which involves the claimed superiority of recall over recognition memory in naturalistic settings, is shown to stem from the common confounding between memory property (quantity vs. accuracy) and 2 other variables that have not generally been distinguished--test format (production vs. selection) and report option (free vs. forced reporting). Three laboratory experiments reveal the fundamentally different roles played by report option and test format in accuracy-based and quantity-based memory research. Implications for memory assessment, metamemory, and the everyday-laboratory controversy are discussed.
Collapse
Affiliation(s)
- A Koriat
- Department of Psychology, University of Haifa, Israel
| | | |
Collapse
|
49
|
Ford DE, Klag MJ, Whelton PK, Goldsmith M, Levine D. Physician knowledge of the CAGE alcohol screening questions and its impact on practice. Alcohol Alcohol 1994; 29:329-36. [PMID: 7945574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A cross-sectional survey of physicians (n = 301) and patients (n = 321) at a university-based department of medicine was completed to determine physician's ability to list CAGE alcohol screening questions and how this knowledge is associated with practice patterns. Forty-five percent of the physicians had heard of the CAGE, but only 14% could list all four of the questions correctly. Physicians who knew the CAGE were more likely to report counseling and referral of their patients who abuse alcohol. However, as assessed by patient interview and chart review, patients with an alcohol abuse problem were no more likely to have been recognized by or to have received more aggressive care from residents who knew the CAGE than patients cared for by residents who did not know the CAGE. Knowledge of an alcohol screening test is not sufficient to change physician practice related to care of patients with an alcohol abuse problem. More attention must be directed towards the development of effective strategies which integrate into clinical practice screening and initial treatment of patients who abuse alcohol.
Collapse
Affiliation(s)
- D E Ford
- Welch Center for Prevention, Epidemiology and Clinical Research, Baltimore, MD
| | | | | | | | | |
Collapse
|
50
|
|