33 results on '"Nudelman, H."'
Search Results
2. K89 acetylated glucose-6-phosphate dehydrogenase (G6PD) in a complex with structural NADP+
- Author
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Wu, F., primary, Muskat, N.H., additional, Nudelman, H., additional, Shahar, A., additional, and Arbely, E., additional
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- 2023
- Full Text
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3. A MamC-MIC insertion in MBP scaffold at position K170
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Nudelman, H., primary and Zarivach, R., additional
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- 2017
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4. Unstructured MamC magnetite-binding protein located between two helices.
- Author
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Nudelman, H., primary and Zarivach, R., additional
- Published
- 2017
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5. MBP-MamC magnetite-interaction component mutant-D70A
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Nudelman, H., primary, Tercedor, C.V., additional, Kolusheva, S., additional, Gonzalez, T.P., additional, Widdrat, M., additional, Grimberg, N., additional, Levi, H., additional, Nelkenbaum, O., additional, Davidove, G., additional, Faivre, D., additional, Jimenez-Lopez, C., additional, and Zarivach, R., additional
- Published
- 2016
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6. MBP-MamC loop structure, a magnetite biomineralizing protein from Magnetospirillium magneticum AMB-1
- Author
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Nudelman, H., primary and Zarivach, R., additional
- Published
- 2016
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- View/download PDF
7. The responses of the left ventricle to left sympathetic burst-like stimulation
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Greene, M. E., Nudelman, H. B., and Clark, Jr., J. W.
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- 1975
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8. Stutterers and Cerebral Blood Flow
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Viswanath, N. S., primary, Rosenfield, D. B., additional, and Nudelman, H. B., additional
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- 1992
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9. Sustained, synchronous oscillations in discharge of sustaining fibers of crayfish optic nerve.
- Author
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Glantz, R M and Nudelman, H B
- Abstract
1. The regularity of the sustaining fiber (SF) steady-state discharge increases with the intensity of a uniform field of illumination. 2. In a high levels of illumination SFs exhibit a highly periodic or rhythmically bursting steady-state discharge. 3. The period of the burst cycle is independent of the light intensity and the mean firing rate. 4. Multimodal interspike-interval histograms in which successive modes decline exponentially suggest that the discharge arises from a regular input. 5. In conditions of uniform illumination, the regular input must be common to all or several SFs since the period of the burst cycle of simultaneously monitored SFs are the same and cross-correlations indicate that the SFs burst in approximate synchrony. 6. It is proposed that the common, regular input is a network of presynaptic elements exhibiting recurrent lateral inhibition. Evidence supporting this hypothesis is that following a brief light pulse to the inhibitory surround, SFs exhibit cycles of silence and bursting, phase-locked to the stimulus but with a period equal to the steady-state burst-cycle period. 7. Furthermore, lateral inhibitory influences are common to several or all SFs as indicated by the close similarity in response time course of two SFs subjected to a common inhibitory stimulus. 8. The response of the lateral pathways to sinusoidally modulated illumination is highly selective to frequencies near the burst-repetition rate. The excitatory pathways exhibit frequency modulation or entrainment over a wide range of input frequencies. 9. The intersustaining burst cycle phase is under partial visual stimulus control (position and intensity) and the possibility of phase coding in the SF ensemble is discussed.
- Published
- 1976
10. Linear integration of convergent visual inputs in an oculomotor reflex pathway.
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Glantz, R M, Nudelman, H B, and Waldrop, B
- Abstract
The functional connectivity between identified visual interneurons [sustaining fibers (SF)] and oculomotor neurons was assessed by simultaneous recording and cross-correlation analysis. A small group of SFs exhibit excitatory functional connections to an identified tonic oculomotor neuron. The excitatory interactions are found exclusively between SFs and oculomotor neurons with similar and/or overlapping excitatory receptive fields. A second group of SFs exhibit inhibitory connections to motor neurons. The excitatory receptive fields of these SFs correspond to the inhibitory receptive fields of the motor neurons. The collective action of the SFs is sufficient to produce all of the steady-state visual behavior of the motor neurons including the increment in firing rate elicited by illumination, unique features of the motor neuron receptive field, and differential sensitivity to blue light and polarized light. Pairs of SFs that converge on the same motor neuron sum their effects linearly. Thus the joint interaction of two SFs on a motor neuron is equal to the sum of the two postsynaptic effects taken separately. Coactivation of excitatory and inhibitory SF inputs to a motor neuron results in a partial cancellation of their postsynaptic effects on the motor neuron's firing rate. The antagonistic interactions protect the system from perturbations by stray light, visual adaptation, and variations in the central excited state. The ensemble information code, at the SF level of the optomotor pathway, is a set of differentially weighted mean firing rates. The weightings reflect differences in the strengths of the several SF-to- motor neuron interactions. One consequence of these differences is a selective weighting of the effects of illumination (in different regions of visual space) on the compensatory eye reflex.
- Published
- 1984
11. Interval coding and band-pass filtering at oculomotor synapses in crayfish.
- Author
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Glantz, R M and Nudelman, H B
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1. Crayfish exhibit steady-state compensatory eyestalk rotations in response to rotations of the organism or the visual surround. For stimuli in the vertical planes (pitch or roll) the visual reflexes are mediated by identified visual interneurons [sustaining fibers (SFs)], which synapse on identified oculomotor neurons (Mns) (18). 2. The optimal visual stimulus is broad-field intense illumination (simulated skylight) distributed over the dorsal half of the cornea. These stimuli are also optimal for eliciting a regular pacing discharge in SFs with dorsal receptive fields (17). Since a unique discharge pattern is associated with the reflex stimulus, we proposed that the pacing discharge interval encodes the stimulus condition and is optimal for driving the motoneuron discharge. 3. The cross-correlation of SF and Mn impulse trains exhibit large peaks (or troughs) at short latencies associated with strong excitatory (or inhibitory) interactions and "secondary effects" at longer delays associated with the periodicity of the Mn impulse train. The secondary peaks and troughs indicate delayed periods of elevated or depressed Mn excitability synchronized to the reference train (SF) events. From the structure of the cross-correlograms and the motoneuron autocorrelograms we predicted that the spike-to-spike synaptic throughput should be differentially sensitive to the various classes of SF interspike intervals. 4. The hypotheses were tested with logical-correlation functions that directly measure the relative synaptic efficacy of several classes of SF intervals during a continuous train at constant mean rate. The results indicate that the SF-to-Mn excitatory synapse is maximally driven by SF impulses separated by approximately 85 ms. These events are about 2.5 times as effective as the impulses associated with short intervals (less than 20 ms) and 1.4 times as effective as the spikes of long intervals (250 ms). The optimal interval in the various preparations is highly to correlated to the period of the Mn discharge and the SF modal interspike interval. Inhibitory synapses are also differentially sensitive to the SF interspike intervals, but they exhibit summation rather than depression in response to short interspike intervals. 5. These results are generally consistent with previously formulated relationships (39), which govern the synaptic modulation of pacemakers and may apply to any synaptic interaction in which the postsynaptic neuron exhibits a regular discharge. 6. Combinations of long and short intervals with the same mean rate as the optimal interval are not as effective in driving the SF-to-Mn synapse.(ABSTRACT TRUNCATED AT 400 WORDS)
- Published
- 1988
12. Ambient lead concentrations in New York City and their health implications
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Nathanson, B. and Nudelman, H.
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Black or African American ,Lead ,Child, Preschool ,Humans ,Infant ,New York City ,Hispanic or Latino ,Child ,Environmental Health ,Research Article ,Vehicle Emissions - Published
- 1980
13. Management of pediatric ankle fractures: comparison of biodegradable PLGA implants with traditional metal screws.
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Nudelman H, Lőrincz A, Lamberti AG, Varga M, Kassai T, and Józsa G
- Abstract
Introduction: The relevance of biodegradable implants has gained more importance in modern clinical practice. The study aimed to evaluate the effects and outcomes of ankle fracture treatment with absorbable implants compared to metal screws. These implants are made from poly l-lactic-co-glycolic acid (PLGA), however, there are several other materials available on the market., Methods: In a retrospective review, a total of 128 patients were under observation, with distal tibial fracture types ranging from Salter-Harris II-IV. In the absorbable group, patients were treated with the implants ( n = 76). The metal group included patients treated with titanium or steel screws ( n = 52). The extremities were placed in a cast for six weeks after surgery and were utilized for another 6-8 weeks. Patients were followed up for 12-30 months and were evaluated accordingly. The authors examined several aspects such as age, gender, open or closed repair, mechanism of injury, length of hospitalization, type of fracture, time of recovery, and complications., Results: There were no statistically significant differences between the groups regarding demographic qualities, such as age, type of fracture, side of injury, and length of cast application ( p > 0.05 in all cases). Out of 76 patients in the PLGA group, only two presented with complications, so reoperation took place. The rest healed without complications or refractures. Two of those treated with metal screws ( n = 52) had minor, and four had major complications with reoperation., Discussion: In pediatric cases, PLGA implants may present excellent results for treating ankle fractures. They do not disturb the growth plate and do not require reoperation. For this reason, they reduce the burden on the patient and the healthcare provider while simultaneously decreasing the risk of complications, such as infections or problems due to general anesthesia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Nudelman, Lőrincz, Lamberti, Varga, Kassai and Józsa.)
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- 2024
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14. Juvenile Osteochondritis Dissecans: A Case Report.
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Nudelman H, Lőrincz A, Kassai T, and Józsa G
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(1) Background: This report aims to illustrate the development, progression, diagnosis, and treatment of chronically present articular surface lesions. (2) Methods: In this report, two patients are described from the point of the initial presentation of symptoms to surgical consultation based on radiologic findings. These patients underwent corrective surgery in the form of mosaicplasty to repair lesions present on the articular surface and the underlying subchondral bone. (3) Discussion: Diagnosing juvenile OCD remains challenging due to its variable clinical presentation and minute radiologic discoveries. X-rays are useful; however, the gold standard remains arthroscopy, which can be both diagnostic and therapeutic. Future prospects include the use of novel sonographic methods and the use of artificial intelligence within the given modalities. (4) Conclusions: The detailed imaging provided by MRI, combined with the insights from X-rays and potentially other modalities, allows for a nuanced understanding of this disease. This comprehensive approach ensures that treatment decisions are well-informed, optimising outcomes for young patients with this condition.
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- 2024
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15. Pediatric Diaphyseal Forearm Fracture Management with Biodegradable Poly-L-Lactide-Co-Glycolide (PLGA) Intramedullary Implants: A Longitudinal Study.
- Author
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Lőrincz A, Lengyel ÁM, Kedves A, Nudelman H, and Józsa G
- Abstract
Background: Pediatric forearm fractures represent a substantial proportion of childhood injuries, requiring effective and minimally invasive treatments. Our study investigated the mid-term outcomes of biodegradable poly-L-lactide-co-glycolide (PLGA) intramedullary implants in managing diaphyseal forearm fractures in children. Methods: A follow-up cohort study was conducted with 38 patients treated with PLGA implants. Control examinations were performed one year post-operation, assessing bone healing through radiographic evaluations and functional outcomes using injured and uninjured limb range of motion (ROM) comparisons. Scarring was evaluated employing the Vancouver Scar Scale (VSS), and satisfaction via a questionnaire. Results: Children were predominantly female (76.4%), with a mean age of 9.71 (SD: 2.69) years. Effective fracture stabilization and bone healing were found in all patients, with a minor reduction (mean difference of -1.5°, p = 0.282) in elbow flexion on the operated side (139.3°) compared to the intact (140.8°). Elbow extension presented negligible average changes (0.2°, p = 0.098). Forearm movements were slightly reduced on the operated side (mean pronation: 80.8° vs. 83.7°, p = 0.166; average supination: 83.5° vs. 85.7°, p = 0.141). Wrist palmar flexion and dorsiflexion showed no significant differences. VSS ratings indicated minimal scarring (mean guardian and doctor scores were 1.13 and 0.55, respectively, p = 0.020), and all patients reported satisfaction with the treatment outcomes. Conclusions: Biodegradable implants are effective for pediatric forearm fractures, providing stable bone healing while preserving functional ROM with minimal scarring and high patient satisfaction. PLGA proved to be a viable alternative to traditional metal implants, eliminating secondary removal surgeries.
- Published
- 2024
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16. Management of Pediatric Superficial Partial-Thickness Burns with Polyhexamethylene Biguanide: Outcomes and Influencing Factors.
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Lőrincz A, Nudelman H, Lamberti AG, Garami A, Tiborcz KA, Kovács TZ, and Józsa G
- Abstract
Background: In burn care, achieving swift healing with minimal complications remains paramount. This investigation assesses the role of polyhexamethylene biguanide (PHMB) in managing pediatric superficial partial-thickness burns, focusing on the effects of various patient-specific factors on recovery. Methods: Through a retrospective analysis of 27 pediatric cases treated with PHMB, we evaluated the impact of age, burn size, dressing frequency, treatment delay, cold therapy application, and analgesic usage on the time until reepithelialization (TTRE). Results: The majority of patients benefited from early cold therapy, yet only 1 in 3 patients received analgesics. A mean healing time of 8.78 (SD: 2.64) days was observed, with the extent of the burn showing a strong correlation (r: 0.63) to TTRE. Most treatments were managed outpatient, evidenced by a negligible average hospital stay (0.96 days), with recorded no complications. Conclusions: Our findings endorse PHMB as a promising treatment for superficial second-degree burns in young patients, due to the observed stable and rapid wound closure without the association of increased risks. Continued exploration into the optimal application of prehospital interventions and the comprehensive benefits of PHMB in pediatric burn management is necessary. Future research should assess long-term outcomes, including functionality, scar quality, and patient satisfaction.
- Published
- 2024
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17. Management of Juvenile Osteochondral Fractures Utilising Absorbable PLGA Implants.
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Nudelman H, Lőrincz A, Lamberti AG, Varga M, Kassai T, and Józsa G
- Abstract
The incidence of articular injury, particularly osteochondral fractures (OCFs), has seen a cinnotable increase in recent years. Regardless of their location, fragments can be overlooked by plain radiographs, which might lead to osteoarthritis in the long run. Diagnostic imaging has a pivotal role in the assessment and classification of the fracture severity, as well as the presence of any associated dislocations. These fractures require surgical intervention for the restoration of joint function and the reduction of long-term complications. This paper aims to present the surgical correction and post-operative treatment of osteochondral fractures with absorbable implants in four children. The following affected areas are discussed: lateral condyle of the femur, patella and radial head. Utilising absorbable implants for the management of OCFs provides numerous advantages, including the elimination of the need for re-anaesthesia and reoperation, reduction of complications and facilitation of early rehabilitation. This approach also minimises the period of hospitalisation and proves effective in pediatric OCF treatment.
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- 2024
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18. A Complex Case of Clino-Syndactyly with Fourth Metacarpal Aplasia.
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Nudelman H, Lőrincz A, Lamberti AG, Kassai T, and Józsa G
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Syndactyly is the most common congenital malformation of the hand, leading to the fusion of the digits and frequently affecting the ring and middle fingers. The incidence is 1 out of 2500 children, predominantly occurring in boys and Caucasians. Clinically, the malformation may present as a soft tissue or bony fusion, resulting in the union of the fingers characterised as complete or incomplete. This fusion may involve the phalanges but may also extend to the carpal/tarsal bones, even to the metacarpal or metatarsal level, rarely to the distal end of the forearm and lower leg. The malformation is mostly isolated but may occur together with other disorders or malformations such as synostosis, acro-syndactyly, cleft hand, clinodactyly, or polydactyly. Syndromic syndactyly can be observed in cases of Apert syndrome, Poland's syndrome, Pfeiffer syndrome, and many others. A girl born in June of 2019 was diagnosed with congenital malformation of the right hand at birth-affecting the right middle, ring, and little fingers, respectively. After X-ray imaging, the fusion of the third and fourth proximal phalanges to a common metacarpal was identified, forming a unique diagnosis of clino-syndactyly with metacarpal aplasia. Surgical intervention was advocated for, including a wedge osteotomy to correct the synchondrosis at the phalangeal base and a dorsal flap to close the interdigital space created during the correction of the III and IV. fingers. A trapezoid flap for the release of the syndactyly of the IV and V. fingers was applied. The paper aims to present this surgical correction and its results regarding an atypical case of syndactyly with clinodactyly and metacarpal aplasia.
- Published
- 2023
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19. Limb girdle muscular disease caused by HMGCR mutation and statin myopathy treatable with mevalonolactone.
- Author
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Yogev Y, Shorer Z, Koifman A, Wormser O, Drabkin M, Halperin D, Dolgin V, Proskorovski-Ohayon R, Hadar N, Davidov G, Nudelman H, Zarivach R, Shelef I, Perez Y, and Birk OS
- Subjects
- Animals, Humans, Mice, Autoantibodies genetics, Hydroxymethylglutaryl CoA Reductases genetics, Hydroxymethylglutaryl CoA Reductases metabolism, Mevalonic Acid, Mutation, Hydroxymethylglutaryl-CoA Reductase Inhibitors adverse effects, Muscular Diseases chemically induced, Muscular Diseases drug therapy, Muscular Diseases genetics
- Abstract
Myopathy is the main adverse effect of the widely prescribed statin drug class. Statins exert their beneficial effect by inhibiting HMG CoA-reductase, the rate-controlling enzyme of the mevalonate pathway. The mechanism of statin myopathy is yet to be resolved, and its treatment is insufficient. Through homozygosity mapping and whole exome sequencing, followed by functional analysis using confocal microscopy and biochemical and biophysical methods, we demonstrate that a distinct form of human limb girdle muscular disease is caused by a pathogenic homozygous loss-of-function missense mutation in HMG CoA reductase ( HMGCR ), encoding HMG CoA-reductase . We biochemically synthesized and purified mevalonolactone, never administered to human patients before, and establish the safety of its oral administration in mice. We then show that its oral administration is effective in treating a human patient with no significant adverse effects. Furthermore, we demonstrate that oral mevalonolactone resolved statin-induced myopathy in mice. We conclude that HMGCR mutation causes a late-onset severe progressive muscular disease, which shows similar features to statin-induced myopathy. Our findings indicate that mevalonolactone is effective both in the treatment of hereditary HMGCR myopathy and in a murine model of statin myopathy. Further large clinical trials are in place to enable the clinical use of mevalonolactone both in the rare orphan disease and in the more common statin myopathy.
- Published
- 2023
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20. Unexpected implications of STAT3 acetylation revealed by genetic encoding of acetyl-lysine.
- Author
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Belo Y, Mielko Z, Nudelman H, Afek A, Ben-David O, Shahar A, Zarivach R, Gordan R, and Arbely E
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- Acetylation, Humans, Phosphorylation, Protein Processing, Post-Translational, Signal Transduction, Betaine metabolism, STAT3 Transcription Factor metabolism
- Abstract
The signal transducer and activator of transcription 3 (STAT3) protein is activated by phosphorylation of a specific tyrosine residue (Tyr705) in response to various extracellular signals. STAT3 activity was also found to be regulated by acetylation of Lys685. However, the molecular mechanism by which Lys685 acetylation affects the transcriptional activity of STAT3 remains elusive. By genetically encoding the co-translational incorporation of acetyl-lysine into position Lys685 and co-expression of STAT3 with the Elk receptor tyrosine kinase, we were able to characterize site-specifically acetylated, and simultaneously acetylated and phosphorylated STAT3. We measured the effect of acetylation on the crystal structure, and DNA binding affinity and specificity of Tyr705-phosphorylated and non-phosphorylated STAT3. In addition, we monitored the deacetylation of acetylated Lys685 by reconstituting the mammalian enzymatic deacetylation reaction in live bacteria. Surprisingly, we found that acetylation, per se, had no effect on the crystal structure, and DNA binding affinity or specificity of STAT3, implying that the previously observed acetylation-dependent transcriptional activity of STAT3 involves an additional cellular component. In addition, we discovered that Tyr705-phosphorylation protects Lys685 from deacetylation in bacteria, providing a new possible explanation for the observed correlation between STAT3 activity and Lys685 acetylation., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
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21. Understanding the Biomineralization Role of Magnetite-Interacting Components (MICs) From Magnetotactic Bacteria.
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Nudelman H, Lee YZ, Hung YL, Kolusheva S, Upcher A, Chen YC, Chen JY, Sue SC, and Zarivach R
- Abstract
Biomineralization is a process that takes place in all domains of life and which usually helps organisms to harden soft tissues by creating inorganic structures that facilitate their biological functions. It was shown that biominerals are under tight biological control via proteins that are involved in nucleation initiation and/or which act as structural skeletons. Magnetotactic bacteria (MTB) use iron biomineralization to create nano-magnetic particles in a specialized organelle, the magnetosome, to align to the geomagnetic field. A specific set of magnetite-associated proteins (MAPs) is involved in regulating magnetite nucleation, size, and shape. These MAPs are all predicted to contain specific 17-22 residue-long sequences involved in magnetite formation. To understand the mechanism of magnetite formation, we focused on three different MAPs, MamC, Mms6 and Mms7, and studied the predicted iron-binding sequences. Using nuclear magnetic resonance (NMR), we differentiated the recognition mode of each MAP based on ion specificity, affinity, and binding residues. The significance of critical residues in each peptide was evaluated by mutation followed by an iron co-precipitation assay. Among the peptides, MamC showed weak ion binding but created the most significant effect in enhancing magnetite particle size, indicating the potency in controlling magnetite particle shape and size. Alternatively, Mms6 and Mms7 had strong binding affinities but less effect in modulating magnetite particle size, representing their major role potentially in initiating nucleation by increasing local metal concentration. Overall, our results explain how different MAPs affect magnetite synthesis, interact with Fe
2+ ions and which residues are important for the MAPs functions.- Published
- 2018
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22. The importance of the helical structure of a MamC-derived magnetite-interacting peptide for its function in magnetite formation.
- Author
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Nudelman H, Perez Gonzalez T, Kolushiva S, Widdrat M, Reichel V, Peigneux A, Davidov G, Bitton R, Faivre D, Jimenez-Lopez C, and Zarivach R
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- Amino Acid Sequence, Bacterial Proteins metabolism, Crystallography, X-Ray, Magnetosomes metabolism, Models, Molecular, Peptide Fragments metabolism, Protein Conformation, Bacterial Proteins chemistry, Ferrosoferric Oxide metabolism, Iron metabolism, Magnetosomes chemistry, Peptide Fragments chemistry
- Abstract
Biomineralization is the process of mineral formation by organisms and involves the uptake of ions from the environment in order to produce minerals, with the process generally being mediated by proteins. Most proteins that are involved in mineral interactions are predicted to contain disordered regions containing large numbers of negatively charged amino acids. Magnetotactic bacteria, which are used as a model system for iron biomineralization, are Gram-negative bacteria that can navigate through geomagnetic fields using a specific organelle, the magnetosome. Each organelle comprises a membrane-enveloped magnetic nanoparticle, magnetite, the formation of which is controlled by a specific set of proteins. One of the most abundant of these proteins is MamC, a small magnetosome-associated integral membrane protein that contains two transmembrane α-helices connected by an ∼21-amino-acid peptide. In vitro studies of this MamC peptide showed that it forms a helical structure that can interact with the magnetite surface and affect the size and shape of the growing crystal. Our results show that a disordered structure of the MamC magnetite-interacting component (MamC-MIC) abolishes its interaction with magnetite particles. Moreover, the size and shape of magnetite crystals grown in in vitro magnetite-precipitation experiments in the presence of this disordered peptide were different from the traits of crystals grown in the presence of other peptides or in the presence of the helical MIC. It is suggested that the helical structure of the MamC-MIC is important for its function during magnetite formation.
- Published
- 2018
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23. Structure-function studies of the magnetite-biomineralizing magnetosome-associated protein MamC.
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Nudelman H, Valverde-Tercedor C, Kolusheva S, Perez Gonzalez T, Widdrat M, Grimberg N, Levi H, Nelkenbaum O, Davidov G, Faivre D, Jimenez-Lopez C, and Zarivach R
- Subjects
- Bacterial Proteins metabolism, Gram-Negative Bacteria metabolism, Magnetosomes physiology, Magnetospirillum, Nanoparticles chemistry, Protein Binding, Structure-Activity Relationship, Bacterial Proteins chemistry, Ferrosoferric Oxide metabolism, Gram-Negative Bacteria chemistry, Magnetosomes chemistry
- Abstract
Magnetotactic bacteria are Gram-negative bacteria that navigate along geomagnetic fields using the magnetosome, an organelle that consists of a membrane-enveloped magnetic nanoparticle. Magnetite formation and its properties are controlled by a specific set of proteins. MamC is a small magnetosome-membrane protein that is known to be active in iron biomineralization but its mechanism has yet to be clarified. Here, we studied the relationship between the MamC magnetite-interaction loop (MIL) structure and its magnetite interaction using an inert biomineralization protein-MamC chimera. Our determined structure shows an alpha-helical fold for MamC-MIL with highly charged surfaces. Additionally, the MamC-MIL induces the formation of larger magnetite crystals compared to protein-free and inert biomineralization protein control experiments. We suggest that the connection between the MamC-MIL structure and the protein's charged surfaces is crucial for magnetite binding and thus for the size control of the magnetite nanoparticles., (Copyright © 2016. Published by Elsevier Inc.)
- Published
- 2016
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24. The FtsZ-like protein FtsZm of Magnetospirillum gryphiswaldense likely interacts with its generic homolog and is required for biomineralization under nitrate deprivation.
- Author
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Müller FD, Raschdorf O, Nudelman H, Messerer M, Katzmann E, Plitzko JM, Zarivach R, and Schüler D
- Subjects
- Bacterial Proteins chemistry, Bacterial Proteins genetics, Cell Division physiology, Cytoskeletal Proteins chemistry, Cytoskeletal Proteins genetics, Magnetospirillum genetics, Models, Molecular, Molecular Sequence Data, Protein Conformation, Bacterial Proteins metabolism, Cytoskeletal Proteins metabolism, Gene Expression Regulation, Bacterial physiology, Magnetospirillum metabolism, Nitrates metabolism
- Abstract
Midcell selection, septum formation, and cytokinesis in most bacteria are orchestrated by the eukaryotic tubulin homolog FtsZ. The alphaproteobacterium Magnetospirillum gryphiswaldense (MSR-1) septates asymmetrically, and cytokinesis is linked to splitting and segregation of an intracellular chain of membrane-enveloped magnetite crystals (magnetosomes). In addition to a generic, full-length ftsZ gene, MSR-1 contains a truncated ftsZ homolog (ftsZm) which is located adjacent to genes controlling biomineralization and magnetosome chain formation. We analyzed the role of FtsZm in cell division and biomineralization together with the full-length MSR-1 FtsZ protein. Our results indicate that loss of FtsZm has a strong effect on microoxic magnetite biomineralization which, however, could be rescued by the presence of nitrate in the medium. Fluorescence microscopy revealed that FtsZm-mCherry does not colocalize with the magnetosome-related proteins MamC and MamK but is confined to asymmetric spots at midcell and at the cell pole, coinciding with the FtsZ protein position. In Escherichia coli, both FtsZ homologs form distinct structures but colocalize when coexpressed, suggesting an FtsZ-dependent recruitment of FtsZm. In vitro analyses indicate that FtsZm is able to interact with the FtsZ protein. Together, our data suggest that FtsZm shares key features with its full-length homolog but is involved in redox control for magnetite crystallization.
- Published
- 2014
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25. Structure prediction of magnetosome-associated proteins.
- Author
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Nudelman H and Zarivach R
- Abstract
Magnetotactic bacteria (MTB) are Gram-negative bacteria that can navigate along geomagnetic fields. This ability is a result of a unique intracellular organelle, the magnetosome. These organelles are composed of membrane-enclosed magnetite (Fe3O4) or greigite (Fe3S4) crystals ordered into chains along the cell. Magnetosome formation, assembly, and magnetic nano-crystal biomineralization are controlled by magnetosome-associated proteins (MAPs). Most MAP-encoding genes are located in a conserved genomic region - the magnetosome island (MAI). The MAI appears to be conserved in all MTB that were analyzed so far, although the MAI size and organization differs between species. It was shown that MAI deletion leads to a non-magnetic phenotype, further highlighting its important role in magnetosome formation. Today, about 28 proteins are known to be involved in magnetosome formation, but the structures and functions of most MAPs are unknown. To reveal the structure-function relationship of MAPs we used bioinformatics tools in order to build homology models as a way to understand their possible role in magnetosome formation. Here we present a predicted 3D structural models' overview for all known Magnetospirillum gryphiswaldense strain MSR-1 MAPs.
- Published
- 2014
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26. Stuttering induced by theophylline.
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Rosenfield DB, McCarthy M, McKinney K, Viswanath NS, and Nudelman HB
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- Asthma drug therapy, Child, Child, Preschool, Female, Humans, Male, Retrospective Studies, Stuttering chemically induced, Theophylline adverse effects
- Abstract
We retrospectively evaluated three fluent asthmatic children who developed speech dysfluency following administration of theophylline. The dysfluency ceased in all three, following discontinuation of the medication. The medication was re-instituted in two patients, prompting return of dysfluency. It is unknown whether the patients had characteristics of "acquired stuttering" or "developmental stuttering." We urge appropriate testing should this complication again occur. This might then provide pharmacologic information regarding stuttering.
- Published
- 1994
27. A model of the phonatory response time of stutterers and fluent speakers to frequency-modulated tones.
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Nudelman HB, Herbrich KE, Hess KR, Hoyt BD, and Rosenfield DB
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- Adult, Feedback, Humans, Male, Middle Aged, Psychoacoustics, Attention physiology, Phonation physiology, Pitch Perception physiology, Reaction Time physiology, Stuttering physiopathology, Verbal Behavior physiology
- Abstract
Stutterers and fluent speakers tracked frequency-modulated tones by humming. The response time (RT) to the first corrective change in fundamental frequency in response to linear ramps of increasing and decreasing frequency was measured. The results demonstrate that RT is a function of the stimulus ramp velocity. A model of this dependency is provided which consists of parameters of threshold frequency and a fixed time delay. The estimated threshold frequency for the fluent speakers is 2.029 Hz with 95% confidence interval: (1.70 Hz, 2.35 Hz) whereas that of the stutterers is 3.937 Hz (3.28 Hz, 4.60 Hz). These threshold frequencies are significantly different (p < 0.0001). This implies that stutterers are slower to respond to changes in frequency than are fluent speakers. The fixed time delays for the two groups are not significantly different. This means that it is possible for the stutterers to respond as fast as the fluent speakers (i.e., their basic "reflexes" are the same); however, they spend more time in the detection of the change in a tracking signal. This supports the model of the stuttered event as being triggered by an instability in a multiloop speech motor control system.
- Published
- 1992
- Full Text
- View/download PDF
28. Neurologic aspects of spasmodic dysphonia.
- Author
-
Rosenfield DB, Donovan DT, Sulek M, Viswanath NS, Inbody GP, and Nudelman HB
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Child, Female, Humans, Hypothyroidism complications, Laryngoscopy, Male, Meige Syndrome complications, Middle Aged, Retrospective Studies, Spasm etiology, Tremor complications, Vocal Cords physiopathology, Voice Disorders physiopathology, Voice Disorders etiology
- Abstract
We discuss the etiology of 100 spasmodic dysphonia patients. Seventy-one patients had underlying essential tremor, 25 had Meige's syndrome, 12 were hypothyroid, and 27 had either a functional disturbance or focal dystonia. Six patients had intermittent breathy dysphonia. A large corpus of spasmodic dysphonia patients have organic neurolaryngeal disease.
- Published
- 1990
29. Ambient lead concentrations in New York City and their health implications.
- Author
-
Nathanson B and Nudelman H
- Subjects
- Black or African American, Child, Child, Preschool, Hispanic or Latino, Humans, Infant, Lead blood, New York City, Vehicle Emissions adverse effects, Environmental Health, Lead adverse effects
- Published
- 1980
30. Sustained oscillations, entrainment and lateral inhibition in the crayfish visual system.
- Author
-
Nudelman HB and Glantz RM
- Subjects
- Action Potentials, Animals, Interneurons physiology, Light, Models, Neurological, Nerve Net physiology, Optic Nerve physiology, Astacoidea physiology, Neural Inhibition, Periodicity, Visual Pathways physiology
- Published
- 1977
31. Comments on "Two-mass models of the vocal cords for natural sounding voice synthesis".
- Author
-
Nudelman HB and Hoyt BD
- Subjects
- Humans, Communication Devices for People with Disabilities, Models, Biological, Self-Help Devices, Vocal Cords physiology
- Abstract
Koizumi et al. [J. Acoust. Soc. Am. 82, 1179-1192 (1987)] have proposed a way to incorporate mucosal waves into previous two-mass mechanical models of the vocal folds. This was accomplished by allowing the mass of the masses to vary with time. The equations of motion Koizumi et al. used to mathematically describe this model neglected terms from the time rate of change of momentum of Newton's second law. In this letter, approximations of the magnitude of this term indicate that it must not be neglected.
- Published
- 1989
- Full Text
- View/download PDF
32. "Stuttering as a complication of strabismus surgery".
- Author
-
Rosenfield DB, Pirozzolo FJ, Nudelman HB, and McIntyre R
- Subjects
- Adolescent, Child, Child, Preschool, Humans, Infant, Strabismus surgery, Stress, Psychological complications, Stuttering etiology
- Published
- 1987
- Full Text
- View/download PDF
33. General Discussion: Session II. Lead.
- Author
-
Nudelman H and Nathanson B
- Published
- 1980
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