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Suresh AK, Greenspon CM, He Q, Rosenow JM, Miller LE, Bensmaia SJ. Sensory computations in the cuneate nucleus of macaques. Proc Natl Acad Sci U S A 2021; 118:e2115772118. [PMID: 34853173 PMCID: PMC8670430 DOI: 10.1073/pnas.2115772118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022] Open
Abstract
Tactile nerve fibers fall into a few classes that can be readily distinguished based on their spatiotemporal response properties. Because nerve fibers reflect local skin deformations, they individually carry ambiguous signals about object features. In contrast, cortical neurons exhibit heterogeneous response properties that reflect computations applied to convergent input from multiple classes of afferents, which confer to them a selectivity for behaviorally relevant features of objects. The conventional view is that these complex response properties arise within the cortex itself, implying that sensory signals are not processed to any significant extent in the two intervening structures-the cuneate nucleus (CN) and the thalamus. To test this hypothesis, we recorded the responses evoked in the CN to a battery of stimuli that have been extensively used to characterize tactile coding in both the periphery and cortex, including skin indentations, vibrations, random dot patterns, and scanned edges. We found that CN responses are more similar to their cortical counterparts than they are to their inputs: CN neurons receive input from multiple classes of nerve fibers, they have spatially complex receptive fields, and they exhibit selectivity for object features. Contrary to consensus, then, the CN plays a key role in processing tactile information.
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Affiliation(s)
- Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637
| | - Charles M Greenspon
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
| | - Qinpu He
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637
| | - Joshua M Rosenow
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Lee E Miller
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208
- Shirley Ryan AbilityLab, Chicago, IL 60611
| | - Sliman J Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637;
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
- Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL 60637
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2
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Suresh AK, Goodman JM, Okorokova EV, Kaufman M, Hatsopoulos NG, Bensmaia SJ. Neural population dynamics in motor cortex are different for reach and grasp. eLife 2020; 9:58848. [PMID: 33200745 PMCID: PMC7688308 DOI: 10.7554/elife.58848] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [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: 05/12/2020] [Accepted: 10/27/2020] [Indexed: 11/25/2022] Open
Abstract
Low-dimensional linear dynamics are observed in neuronal population activity in primary motor cortex (M1) when monkeys make reaching movements. This population-level behavior is consistent with a role for M1 as an autonomous pattern generator that drives muscles to give rise to movement. In the present study, we examine whether similar dynamics are also observed during grasping movements, which involve fundamentally different patterns of kinematics and muscle activations. Using a variety of analytical approaches, we show that M1 does not exhibit such dynamics during grasping movements. Rather, the grasp-related neuronal dynamics in M1 are similar to their counterparts in somatosensory cortex, whose activity is driven primarily by afferent inputs rather than by intrinsic dynamics. The basic structure of the neuronal activity underlying hand control is thus fundamentally different from that underlying arm control.
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Affiliation(s)
- Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, United States
| | - James M Goodman
- Committee on Computational Neuroscience, University of Chicago, Chicago, United States
| | - Elizaveta V Okorokova
- Committee on Computational Neuroscience, University of Chicago, Chicago, United States
| | - Matthew Kaufman
- Committee on Computational Neuroscience, University of Chicago, Chicago, United States.,Department of Organismal Biology and Anatomy, University of Chicago, Chicago, United States.,Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, United States
| | - Nicholas G Hatsopoulos
- Committee on Computational Neuroscience, University of Chicago, Chicago, United States.,Department of Organismal Biology and Anatomy, University of Chicago, Chicago, United States.,Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, United States
| | - Sliman J Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, United States.,Department of Organismal Biology and Anatomy, University of Chicago, Chicago, United States.,Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, United States
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3
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Khairkar SR, Pansare AV, Shedge AA, Chhatre SY, Suresh AK, Chakrabarti S, Patil VR, Nagarkar AA. Hydrophobic interpenetrating polyamide-PDMS membranes for desalination, pesticides removal and enhanced chlorine tolerance. Chemosphere 2020; 258:127179. [PMID: 32554002 DOI: 10.1016/j.chemosphere.2020.127179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
Hydrophobic membranes for desalination and toxic organic pollutant removal have been fabricated using polyamide - PDMS (polydimethylsiloxane) chemistries in a one-step protocol. The curing of polyamide and PDMS are orthogonal and co-curing both networks imparts hydrophobicity to the thin film composite membranes. The membranes exhibit increased adsorption of pesticides from the feed water along with maintaining excellent salt rejection capability (97% NaCl rejection), thus giving the membranes a multifunctional character. Three toxic pesticides have been used in this study to demonstrate the viability of combining osmosis desalination technology with organic matter adsorption. The membranes also show excellent resistance to fouling by toxic pesticides (85% salt rejection vs 67% for commercial membranes in the presence of pesticides) and significantly improved chlorine tolerance (93.8% salt rejection vs 86.5% for commercial membranes after 20 h of exposure to sodium hypochlorite solution).
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Affiliation(s)
- Shyam R Khairkar
- Research and Services Division of Materials Data and Integrated System (MaDIS), National Institute for Materials Science (NIMS), Tsukuba Ibaraki, 305-0047, Japan
| | - Amol V Pansare
- Mechanical Systems Engineering, Swiss Federal Laboratories for Materials Science and Technology-Empa, 8600, Dübendorf, Switzerland
| | - Amol A Shedge
- Department of Chemistry, University of Mumbai, Mumbai, 400098, India
| | - Shraddha Y Chhatre
- National Chemical Laboratory (NCL) Dr. Homi Bhabha Road, Pune, 411008, India
| | - A K Suresh
- Department of Chemical Engineering, Indian Institute of Technology, Bombay, Bombay, 400076, Maharashtra, India
| | - Subhananda Chakrabarti
- Department of Electrical Engineering, Indian Institute of Technology Bombay (IITB), 400076, India
| | | | - Amit A Nagarkar
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA.
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4
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Callier T, Suresh AK, Bensmaia SJ. Neural Coding of Contact Events in Somatosensory Cortex. Cereb Cortex 2020; 29:4613-4627. [PMID: 30668644 DOI: 10.1093/cercor/bhy337] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [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: 05/10/2018] [Revised: 12/07/2018] [Accepted: 12/17/2018] [Indexed: 01/22/2023] Open
Abstract
Manual interactions with objects require precise and rapid feedback about contact events. These tactile signals are integrated with motor plans throughout the neuraxis to achieve dexterous object manipulation. To better understand the role of somatosensory cortex in interactions with objects, we measured, using chronically implanted arrays of electrodes, the responses of populations of somatosensory neurons to skin indentations designed to simulate the initiation, maintenance, and termination of contact with an object. First, we find that the responses of somatosensory neurons to contact onset and offset dwarf their responses to maintenance of contact. Second, we show that these responses rapidly and reliably encode features of the simulated contact events-their timing, location, and strength-and can account for the animals' performance in an amplitude discrimination task. Third, we demonstrate that the spatiotemporal dynamics of the population response in cortex mirror those of the population response in the nerves. We conclude that the responses of populations of somatosensory neurons are well suited to encode contact transients and are consistent with a role of somatosensory cortex in signaling transitions between task subgoals.
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Affiliation(s)
- Thierri Callier
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Sliman J Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA.,Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA
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5
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Goodman JM, Tabot GA, Lee AS, Suresh AK, Rajan AT, Hatsopoulos NG, Bensmaia S. Postural Representations of the Hand in the Primate Sensorimotor Cortex. Neuron 2019; 104:1000-1009.e7. [PMID: 31668844 PMCID: PMC7172114 DOI: 10.1016/j.neuron.2019.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [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: 03/07/2019] [Revised: 06/04/2019] [Accepted: 09/05/2019] [Indexed: 01/07/2023]
Abstract
Manual dexterity requires proprioceptive feedback about the state of the hand. To date, study of the neural basis of proprioception in the cortex has focused primarily on reaching movements to the exclusion of hand-specific behaviors such as grasping. To fill this gap, we record both time-varying hand kinematics and neural activity evoked in somatosensory and motor cortices as monkeys grasp a variety of objects. We find that neurons in the somatosensory cortex, as well as in the motor cortex, preferentially track time-varying postures of multi-joint combinations spanning the entire hand. This contrasts with neural responses during reaching movements, which preferentially track time-varying movement kinematics of the arm, such as velocity and speed of the limb, rather than its time-varying postural configuration. These results suggest different representations of arm and hand movements suited to the different functional roles of these two effectors.
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Affiliation(s)
- James M Goodman
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Gregg A Tabot
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Alex S Lee
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Alexander T Rajan
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Nicholas G Hatsopoulos
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA; Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA; Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL, USA
| | - Sliman Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA; Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA; Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL, USA.
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6
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Govindan K, Suresh AK, Sakthivel T, Murugesan K, Mohan R, Gunasekaran V, Jang A. Effect of peroxomonosulfate, peroxodisulfate and hydrogen peroxide on graphene oxide photocatalytic performances in methyl orange dye degradation. Chemosphere 2019; 237:124479. [PMID: 31400739 DOI: 10.1016/j.chemosphere.2019.124479] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/30/2019] [Accepted: 07/28/2019] [Indexed: 06/10/2023]
Abstract
Carbocatalyst GO photocatalytic mechanism and performances in the presence of an electron scavenger (ES) has been consciously discussed herein. Single layer GO photocatalyst has been synthesized by Hummer's method and photocatalyst characteristics are gathered by different analytical methods. Studies ensured the formation of a good crystalline GO that contains number of oxygenated functional groups, with average crystalline size of the sp2 domain in 18.24 nm. Optical studies suggest that optical band gap of the GO nanosheet photocatalyst is found in the range of 3.19-4.4 eV. TEM analysis confirms the formation of a single layer GO nanosheet. Photocatalytic study justifies that in the absence of ES, 24% mineralization efficiency is achieved with GO as a photocatalyst, whereas in the presence of ES such as PMS, PDS and HP the mineralization efficiency is considerably enhanced up to 91%, 77% and 65% respectively. Moreover, photocatalytic degradation intermediate byproducts were also examined through LC-MS analysis. The study substantiates methyl orange dye degradation undergoes via the multiple degradation pathway such as (i) azo bond cleavage and hydroxylation, (ii), asymmetric cleavage followed by reduction of sulfonate group and aromatic ring removal and (iii) consecutive demethylation reactions and sulfonate group removal. Rationalized the contributing effects of process parameters towards the photocatalytic degradation of methyl orange using a RSM based on CCD validation. The validation reveals that most significant process parameter affects degradation process are the irradiation time, catalyst loading and choice of ES.
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Affiliation(s)
- Kadarkarai Govindan
- SWAT Laboratory, Graduate School of Water Resources, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Republic of Korea.
| | - A K Suresh
- Department of Chemical Engineering and Material Science, Amrita School of Engineering Coimbatore, Amrita Vishwa Vidyapeetham, Coimbatore, 641 112, India
| | - Thangavel Sakthivel
- Key Lab of Advanced Transducers and Intelligent Control System, Taiyuan University of Technology, Taiyuan, 030024, PR China
| | - Kalpana Murugesan
- Department of Nano Science and Technology, Tamil Nadu Agricultural University (TNAU), Tamil Nadu, India
| | - Raja Mohan
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, 641 114, India
| | - Venugopal Gunasekaran
- Department of Material Science, School of Technology, Central University of Tamil Nadu, Thiruvarur, 610 005, Tamil Nadu, India
| | - Am Jang
- SWAT Laboratory, Graduate School of Water Resources, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Republic of Korea.
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7
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Clawson BC, Durkin J, Suresh AK, Pickup EJ, Broussard CG, Aton SJ. Sleep Promotes, and Sleep Loss Inhibits, Selective Changes in Firing Rate, Response Properties and Functional Connectivity of Primary Visual Cortex Neurons. Front Syst Neurosci 2018; 12:40. [PMID: 30245617 PMCID: PMC6137342 DOI: 10.3389/fnsys.2018.00040] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [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: 06/01/2018] [Accepted: 08/20/2018] [Indexed: 11/13/2022] Open
Abstract
Recent studies suggest that sleep differentially alters the activity of cortical neurons based on firing rates during preceding wake—increasing the firing rates of sparsely firing neurons and decreasing those of faster firing neurons. Because sparsely firing cortical neurons may play a specialized role in sensory processing, sleep could facilitate sensory function via selective actions on sparsely firing neurons. To test this hypothesis, we analyzed longitudinal electrophysiological recordings of primary visual cortex (V1) neurons across a novel visual experience which induces V1 plasticity (or a control experience which does not), and a period of subsequent ad lib sleep or partial sleep deprivation. We find that across a day of ad lib sleep, spontaneous and visually-evoked firing rates are selectively augmented in sparsely firing V1 neurons. These sparsely firing neurons are more highly visually responsive, and show greater orientation selectivity than their high firing rate neighbors. They also tend to be “soloists” instead of “choristers”—showing relatively weak coupling of firing to V1 population activity. These population-specific changes in firing rate are blocked by sleep disruption either early or late in the day, and appear to be brought about by increases in neuronal firing rates across bouts of rapid eye movement (REM) sleep. Following a patterned visual experience that induces orientation-selective response potentiation (OSRP) in V1, sparsely firing and weakly population-coupled neurons show the highest level of sleep-dependent response plasticity. Across a day of ad lib sleep, population coupling strength increases selectively for sparsely firing neurons—this effect is also disrupted by sleep deprivation. Together, these data suggest that sleep may optimize sensory function by augmenting the functional connectivity and firing rate of highly responsive and stimulus-selective cortical neurons, while simultaneously reducing noise in the network by decreasing the activity of less selective, faster-firing neurons.
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Affiliation(s)
- Brittany C Clawson
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Jaclyn Durkin
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, United States
| | - Emily J Pickup
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Christopher G Broussard
- Information Technology Advocacy and Research Support, College of Literature, Science and the Arts, University of Michigan, Ann Arbor, MI, United States
| | - Sara J Aton
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
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8
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Suresh AK, Winberry JE, Versteeg C, Chowdhury R, Tomlinson T, Rosenow JM, Miller LE, Bensmaia SJ. Methodological considerations for a chronic neural interface with the cuneate nucleus of macaques. J Neurophysiol 2017; 118:3271-3281. [PMID: 28904101 PMCID: PMC5814711 DOI: 10.1152/jn.00436.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [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: 06/13/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 12/13/2022] Open
Abstract
While the response properties of neurons in the somatosensory nerves and anterior parietal cortex have been extensively studied, little is known about the encoding of tactile and proprioceptive information in the cuneate nucleus (CN) or external cuneate nucleus (ECN), the first recipients of upper limb somatosensory afferent signals. The major challenge in characterizing neural coding in CN/ECN has been to record from these tiny, difficult-to-access brain stem structures. Most previous investigations of CN response properties have been carried out in decerebrate or anesthetized animals, thereby eliminating the well-documented top-down signals from cortex, which likely exert a strong influence on CN responses. Seeking to fill this gap in our understanding of somatosensory processing, we describe an approach to chronically implanting arrays of electrodes in the upper limb representation in the brain stem in primates. First, we describe the topography of CN/ECN in rhesus macaques, including its somatotopic organization and the layout of its submodalities (touch and proprioception). Second, we describe the design of electrode arrays and the implantation strategy to obtain stable recordings. Third, we show sample responses of CN/ECN neurons in brain stem obtained from awake, behaving monkeys. With this method, we are in a position to characterize, for the first time, somatosensory representations in CN and ECN of primates.NEW & NOTEWORTHY In primates, the neural basis of touch and of our sense of limb posture and movements has been studied in the peripheral nerves and in somatosensory cortex, but coding in the cuneate and external cuneate nuclei, the first processing stage for these signals in the central nervous system, remains an enigma. We have developed a method to record from these nuclei, thereby paving the way to studying how sensory information from the limb is encoded there.
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Affiliation(s)
- Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois
| | - Jeremy E Winberry
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois
| | - Christopher Versteeg
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois
| | - Raeed Chowdhury
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois
| | - Tucker Tomlinson
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Joshua M Rosenow
- Department of Neurosurgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and
| | - Lee E Miller
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Sliman J Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois;
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois
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9
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Saal HP, Suresh AK, Solorzano LE, Weber AI, Bensmaia SJ. The Effect of Contact Force on the Responses of Tactile Nerve Fibers to Scanned Textures. Neuroscience 2017; 389:99-103. [PMID: 28844003 DOI: 10.1016/j.neuroscience.2017.08.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [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: 07/22/2017] [Accepted: 08/11/2017] [Indexed: 10/19/2022]
Abstract
The perception of fine textures relies on highly precise and repeatable spiking patterns evoked in tactile afferents. These patterns have been shown to depend not only on the surface microstructure and material but also on the speed at which it moves across the skin. Interestingly, the perception of texture is independent of scanning speed, implying the existence of downstream neural mechanisms that correct for scanning speed in interpreting texture signals from the periphery. What force is applied during texture exploration also has negligible effects on how the surface is perceived, but the consequences of changes in contact force on the neural responses to texture have not been described. In the present study, we measure the signals evoked in tactile afferents of macaques to a diverse set of textures scanned across the skin at two different contact forces and find that responses are largely independent of contact force over the range tested. We conclude that the force invariance of texture perception reflects the force independence of texture representations in the nerve.
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Affiliation(s)
- Hannes P Saal
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, United States
| | | | - Alison I Weber
- Department of Biophysics and Physiology, University of Washington, Seattle, WA, United States
| | - Sliman J Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, United States; Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, United States.
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10
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Dai C, Suresh NL, Suresh AK, Rymer WZ, Hu X. Altered Motor Unit Discharge Coherence in Paretic Muscles of Stroke Survivors. Front Neurol 2017; 8:202. [PMID: 28555126 PMCID: PMC5430034 DOI: 10.3389/fneur.2017.00202] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [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: 11/18/2016] [Accepted: 04/25/2017] [Indexed: 11/24/2022] Open
Abstract
After a cerebral stroke, a series of changes at the supraspinal and spinal nervous system can alter the control of muscle activation, leading to persistent motor impairment. However, the relative contribution of these different levels of the nervous system to impaired muscle activation is not well understood. The coherence of motor unit (MU) spike trains is considered to partly reflect activities of higher level control, with different frequency band representing different levels of control. Accordingly, the objective of this study was to quantify the different sources of contribution to altered muscle activation. We examined the coherence of MU spike trains decomposed from surface electromyogram (sEMG) of the first dorsal interosseous muscle on both paretic and contralateral sides of 14 hemispheric stroke survivors. sEMG was obtained over a range of force contraction levels at 40, 50, and 60% of maximum voluntary contraction. Our results showed that MU coherence increased significantly in delta (1–4 Hz), alpha (8–12 Hz), and beta (15–30 Hz) bands on the affected side compared with the contralateral side, but was maintained at the same level in the gamma (30–60 Hz) band. In addition, no significant alteration was observed across medium–high force levels (40–60%). These results indicated that the common synaptic input to motor neurons increased on the paretic side, and the increased common input can originate from changes at multiple levels, including spinal and supraspinal levels following a stroke. All these changes can contribute to impaired activation of affected muscles in stroke survivors. Our findings also provide evidence regarding the different origins of impaired muscle activation poststroke.
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Affiliation(s)
- Chenyun Dai
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC, USA
| | - Nina L Suresh
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA.,Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - William Zev Rymer
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA.,Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Xiaogang Hu
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC, USA
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11
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Chavare A, Chowdari P, Ghosh S, Pawar P, Patkar M, Dakave S, Gota V, Chaudhari P, Chiplunkar SV, Kane S, Suresh AK, Bellare J. Safety and bioactivity studies of Jasad Bhasma and its in-process intermediate in Swiss mice. J Ethnopharmacol 2017; 197:73-86. [PMID: 27377339 DOI: 10.1016/j.jep.2016.06.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 05/26/2016] [Accepted: 06/17/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Bhasma, Ayurvedic medicinal preparations, are prepared using herbs and minerals on following long iterative procedures. However, industrially mercury and sulphur are more commonly used to prepare bhasma from its raw material. The end point of this iterative procedure is mainly judged by the traditional tests specifying physical appearance of the powders. They fail to give better idea about chemical nature of the material. Moreover, the differences in biological activity of final product verses intermediate are not addressed. AIM OF THE STUDY To compare the physicochemical as well as biological properties of the Jasad bhasma and its in-process intermediate using modern science methods. MATERIALS AND METHODS The Jasad bhasma and its in-process intermediate are characterized for their physicochemical properties using electron microscopy, x-ray diffraction and CHNS(O) analysis. The biological effects of both the preparations are then studied. The bioaccumulation of zinc, effect on liver antioxidant status, liver and kidney function (by conventional tests as well as SPECT: Single Photon Emission Computed Tomography), effect on blood cells and effect on immune system are studied in mice model, Swiss albino. Since bhasma is given with an accompaniment (anupan), all the bioactivity studies were carried out by administering the preparation with and without Amala powder (Phyllanthus emblica L., fruit, dry powder) as anupan. RESULTS The XRD results accompanied with Rietveld analysis indicate that the final bhasma is mainly oxide of zinc, whereas the intermediate is mainly sulphide of zinc. The animal studies show that the bhasma as well as its intermediate do not lead to any bioaccumulation of zinc in major organs, when administered with and without anupan. Both, bhasma and intermediate do not cause any deleterious effects on kidney and liver as indicated by blood biochemistry and SPECT studies. However, the intermediate perturbs antioxidant status more and affects the platelet turnover, in comparison with bhasma. On 28day treatment, the bhasma treated animals show prominence of TH1 mediated immune response whereas, intermediate treated animals show prominence of TH2 mediated immune response. CONCLUSION A set of simple modern microscopy and diffraction techniques can affirmatively identify in-process intermediate from the final preparation. These can be used to decide the end point of long and iterative preparation methods in accordance with modern science practices. The differences in physicochemical properties of particles from the two preparations reflect in their different biological effects. Moreover, the bhasma affects several components of biological systems which again in-turn interact with each other, which emphasizes the need of multifaceted studies in this field.
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Affiliation(s)
- Aparna Chavare
- Department of Chemical Engineering, IIT Bombay, Mumbai 400 076, India
| | - Praneeth Chowdari
- Department of Clinical Pharmacology, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - Sandipto Ghosh
- Department of Immunology, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - Priyanka Pawar
- Small Animal Imaging Facility, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - Meena Patkar
- Small Animal Imaging Facility, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - Suresh Dakave
- Small Animal Imaging Facility, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - Vikram Gota
- Department of Immunology, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - Pradip Chaudhari
- Department of Immunology, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - S V Chiplunkar
- Small Animal Imaging Facility, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai - 410 210, India
| | - Shantaram Kane
- Department of Chemical Engineering, IIT Bombay, Mumbai 400 076, India
| | - A K Suresh
- Department of Chemical Engineering, IIT Bombay, Mumbai 400 076, India; Department of Bioscience and Bioengineering, IIT Bombay, Mumbai 400 076, India
| | - Jayesh Bellare
- Department of Chemical Engineering, IIT Bombay, Mumbai 400 076, India; Department of Bioscience and Bioengineering, IIT Bombay, Mumbai 400 076, India.
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12
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Suresh AK, Saal HP, Bensmaia SJ. Edge orientation signals in tactile afferents of macaques. J Neurophysiol 2016; 116:2647-2655. [PMID: 27655968 DOI: 10.1152/jn.00588.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/15/2016] [Indexed: 11/22/2022] Open
Abstract
The orientation of edges indented into the skin has been shown to be encoded in the responses of neurons in primary somatosensory cortex in a manner that draws remarkable analogies to their counterparts in primary visual cortex. According to the classical view, orientation tuning arises from the integration of untuned input from thalamic neurons with aligned but spatially displaced receptive fields (RFs). In a recent microneurography study with human subjects, the precise temporal structure of the responses of individual mechanoreceptive afferents to scanned edges was found to carry information about their orientation. This putative mechanism could in principle contribute to or complement the classical rate-based code for orientation. In the present study, we further examine orientation information carried by mechanoreceptive afferents of Rhesus monkeys. To this end, we record the activity evoked in cutaneous mechanoreceptive afferents when edges are indented into or scanned across the skin. First, we confirm that information about the edge orientation can be extracted from the temporal patterning in afferent responses of monkeys, as is the case in humans. Second, we find that while the coarse temporal profile of the response can be predicted linearly from the layout of the RF, the fine temporal profile cannot. Finally, we show that orientation signals in tactile afferents are often highly dependent on stimulus features other than orientation, which complicates putative decoding strategies. We discuss the challenges associated with establishing a neural code at the somatosensory periphery, where afferents are exquisitely sensitive and nearly deterministic.
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Affiliation(s)
- Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois; and
| | - Hannes P Saal
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois
| | - Sliman J Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois; and .,Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois
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Hu X, Suresh AK, Rymer WZ, Suresh NL. Altered motor unit discharge patterns in paretic muscles of stroke survivors assessed using surface electromyography. J Neural Eng 2016; 13:046025. [PMID: 27432656 DOI: 10.1088/1741-2560/13/4/046025] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Hemispheric stroke survivors often show impairments in voluntary muscle activation. One potential source of these impairments could come from altered control of muscle, via disrupted motor unit (MU) firing patterns. In this study, we sought to determine whether MU firing patterns are modified on the affected side of stroke survivors, as compared with the analogous contralateral muscle. APPROACH Using a novel surface electromyogram (EMG) sensor array, coupled with advanced template recognition software (dEMG) we recorded surface EMG signals over the first dorsal interosseous (FDI) muscle on both paretic and contralateral sides. Recordings were made as stroke survivors produced isometric index finger abductions over a large force range (20%-60% of maximum). Utilizing the dEMG algorithm, MU firing rates, recruitment thresholds, and action potential amplitudes were estimated for concurrently active MUs in each trial. MAIN RESULTS Our results reveal significant changes in the firing rate patterns in paretic FDI muscle, in that the discharge rates, characterized in relation to recruitment force threshold and to MU size, were less clearly correlated with recruitment force than in contralateral FDI muscles. Firing rates in the affected muscle also did not modulate systematically with the level of voluntary muscle contraction, as would be expected in intact muscles. These disturbances in firing properties also correlated closely with the impairment of muscle force generation. SIGNIFICANCE Our results provide strong evidence of disruptions in MU firing behavior in paretic muscles after a hemispheric stroke, suggesting that modified control of the spinal motoneuron pool could be a contributing factor to muscular weakness in stroke survivors.
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Affiliation(s)
- Xiaogang Hu
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, USA. Department of Biomedical Engineering, University of North Carolina at Chapel Hill and NC State University at Raleigh, USA
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14
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Hu X, Suresh AK, Rymer WZ, Suresh NL. Assessing altered motor unit recruitment patterns in paretic muscles of stroke survivors using surface electromyography. J Neural Eng 2015; 12:066001. [PMID: 26402920 DOI: 10.1088/1741-2560/12/6/066001] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The advancement of surface electromyogram (sEMG) recording and signal processing techniques has allowed us to characterize the recruitment properties of a substantial population of motor units (MUs) non-invasively. Here we seek to determine whether MU recruitment properties are modified in paretic muscles of hemispheric stroke survivors. APPROACH Using an advanced EMG sensor array, we recorded sEMG during isometric contractions of the first dorsal interosseous muscle over a range of contraction levels, from 20% to 60% of maximum, in both paretic and contralateral muscles of stroke survivors. Using MU decomposition techniques, MU action potential amplitudes and recruitment thresholds were derived for simultaneously activated MUs in each isometric contraction. MAIN RESULTS Our results show a significant disruption of recruitment organization in paretic muscles, in that the size principle describing recruitment rank order was materially distorted. MUs were recruited over a very narrow force range with increasing force output, generating a strong clustering effect, when referenced to recruitment force magnitude. Such disturbances in MU properties also correlated well with the impairment of voluntary force generation. SIGNIFICANCE Our findings provide direct evidence regarding MU recruitment modifications in paretic muscles of stroke survivors, and suggest that these modifications may contribute to weakness for voluntary contractions.
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Affiliation(s)
- Xiaogang Hu
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA
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15
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Kandar S, Suresh AK, Noronha SB. (R)-PAC biosynthesis in [BMIM][PF₆]/aqueous biphasic system using Saccharomyces cerevisiae BY4741 cells. Appl Biochem Biotechnol 2014; 175:1771-88. [PMID: 25424285 DOI: 10.1007/s12010-014-1394-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 11/12/2014] [Indexed: 11/28/2022]
Abstract
(R)-phenylacetylcarbinol or (R)-PAC is a pharmaceutical precursor of (1R, 2S) ephedrine and (1S, 2S) pseudoephedrine. Biotransformation of benzaldehyde and glucose by pyruvate decarboxylase produces (R)-PAC. This biotransformation suffers from toxicity of the substrate, product [(R)-PAC] and by-product (benzyl alcohol). In the present study, ionic liquid/aqueous biphasic system was employed to enhance (R)-PAC production. Fermented broth was the reaction medium in which Saccharomyces cerevisiae BY4741 was the source of pyruvate decarboxylase. Hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) was the non-aqueous phase in which toxic compounds reside. Biocompatibility of [BMIM][PF6] and adequate distribution coefficients of benzaldehyde, (R)-PAC and benzyl alcohol were determined. A Box-Behnken design and response surface methodology were used for the optimization of biotransformation variables in order to maximize (R)-PAC yield and productivity. The results showed higher (R)-PAC yield and productivity of ∼1.5-fold each in the biphasic biotransformation of phase volume ratio 0.05 as compared to the monophasic (conventional) biotransformation. Moreover, the level of major by-product benzyl alcohol was also 3.5-fold lower in biphasic biotransformation. [BMIM][PF6]/aqueous biphasic system is a new approach which could intensify the (R)-PAC production.
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Affiliation(s)
- Smita Kandar
- Department of Bioscience and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India,
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16
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Suresh AK, Hu X, Powers RK, Heckman CJ, Suresh NL, Rymer WZ. Changes in motoneuron afterhyperpolarization duration in stroke survivors. J Neurophysiol 2014; 112:1447-56. [PMID: 24920018 DOI: 10.1152/jn.01091.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hemispheric brain injury resulting from a stroke is often accompanied by muscle weakness in limbs contralateral to the lesion. In the present study, we investigated whether weakness in contralesional hand muscle in stroke survivors is partially attributable to alterations in motor unit activation, including alterations in firing rate modulation range. The afterhyperpolarization (AHP) potential of a motoneuron is a primary determinant of motoneuron firing rate. We examined differences in AHP duration in motoneurons innervating paretic and less impaired (contralateral) limb muscles of hemiparetic stroke survivors as well as in control subjects. A novel surface EMG (sEMG) electrode was used to record motor units from the first dorsal interosseous muscle. The sEMG data were subsequently decomposed to derive single-motor unit events, which were then utilized to produce interval (ISI) histograms of the motoneuron discharges. A modified version of interval death rate (IDR) analysis was used to estimate AHP duration. Results from data analyses performed on both arms of 11 stroke subjects and in 7 age-matched control subjects suggest that AHP duration is significantly longer for motor units innervating paretic muscle compared with units in contralateral muscles and in units of intact subjects. These results were supported by a coefficient of variation (CV) analysis showing that paretic motor unit discharges have a lower CV than either contralateral or control units. This study suggests that after stroke biophysical changes occur at the motoneuron level, potentially contributing to lower firing rates and potentially leading to less efficient force production in paretic muscles.
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Affiliation(s)
- Aneesha K Suresh
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois;
| | - Xiaogang Hu
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois
| | - Randall K Powers
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington
| | - C J Heckman
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, Illinois; Department of Physiology, Northwestern University, Chicago, Illinois; and
| | - Nina L Suresh
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois
| | - William Zev Rymer
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, Illinois; Department of Biomedical Engineering, Northwestern University, Chicago, Illinois
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Suresh AK, Hu X, Powers RK, Rymer WZ. Examination of afterhyperpolarization duration changes in motoneurons innervating paretic muscles in stroke survivors. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2012:3580-3. [PMID: 23366701 DOI: 10.1109/embc.2012.6346740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The after hyperpolarization (AHP) of a motoneuron is a primary determinant of motoneuron firing rate. Any increase in its duration or amplitude could alter normal motor unit (MU) firing rate properties in stroke, and potentially impact muscle force generation. The objective of this preliminary study was to examine potential differences in afterhyperpolarization (AHP) duration of motoneurons innervating paretic and contralateral limb muscles of hemiparetic stroke survivors. A novel surface EMG (sEMG) electrode was used to record from the first dorsal interosseous muscle (FDI) of three hemiparetic stroke survivors. sEMG data was decomposed to derive single motor unit (SMU) events, which were subsequently utilized to produce interval (ISI) histograms of the motor unit discharge. Interval Death Rate (IDR) analysis was then used to transform ISI histograms into death rate plots. [1] The prescribed IDR analysis method [1] involves a final transformation of death rate plots into an estimated AHP time course. The present study uses a modified method of interpreting death rate plots in order to determine AHP duration. AHP durations from this analysis are similar to durations obtained from ISI variability analysis. [2] Results from three subjects indicate that on average, motor units on the paretic side have a longer AHP duration than the contralateral side, potentially contributing to lower firing rates, and to less efficient force production in paretic muscles.
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Affiliation(s)
- Aneesha K Suresh
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Illinois, USA.
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18
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Hu X, Suresh AK, Li X, Rymer WZ, Suresh NL. Impaired motor unit control in paretic muscle post stroke assessed using surface electromyography: a preliminary report. Annu Int Conf IEEE Eng Med Biol Soc 2012; 2012:4116-4119. [PMID: 23366833 DOI: 10.1109/embc.2012.6346872] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The objective of this preliminary study was to examine the possible contribution of disordered control of motor unit (MU) recruitment and firing patterns in muscle weakness post-stroke. A novel surface EMG (sEMG) recording and decomposition system was used to record sEMG signals and extract single MU activities from the first dorsal interosseous muscle (FDI) of two hemiparetic stroke survivors. To characterize MU reorganization, an estimate of the motor unit action potential (MUAP) amplitude was derived using spike triggered averaging of the sEMG signal. The MUs suitable for further analysis were selected using a set of statistical tests that assessed the variability of the morphological characteristics of the MUAPs. Our preliminary results suggest a disrupted orderly recruitment based on MUAP size, a compressed recruitment range, and reduced firing rates evident in the paretic muscle compared with the contralateral muscle of one subject with moderate impairment. In contrast, the MU organization was largely similar bilaterally for the subject with minor impairment. The preliminary results suggest that MU organizational changes with respect to recruitment and rate modulation can contribute to muscle weakness post-stroke. The contrasting results of the two subjects indicate that the degree of MU reorganization may be associated with the degree of the functional impairment, which reveals the differential diagnostic capability of the sEMG decomposition system.
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Affiliation(s)
- Xiaogang Hu
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, IL, USA.
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Pyrgiotakis G, Bhowmick TK, Finton K, Suresh AK, Kane SG, Bellare JR, Moudgil BM. Cell (A549)-particle (Jasada Bhasma) interactions using Raman spectroscopy. Biopolymers 2008; 89:555-64. [PMID: 18253947 DOI: 10.1002/bip.20947] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Current methods for the evaluation of cell interactions with particles are nonspecific, slow, and invasive to the cells. Raman spectroscopy is a noninvasive technique, and is used in the present study to investigate particle-cell interactions. The main focus of the present study is to employ Raman spectroscopy for investigating the interaction of human lung adenocarcinoma cell line (A549) with the particulate system Jasada Bhasma, a traditional Indian medicine. Jasada Bhasma is a unique preparation of zinc and is traditionally used for the treatment of various diseases like diabetes, age-related eye diseases, and as a health promotional tonic. The Raman spectral analysis is executed by identifying the difference in intracellular DNA/RNA, and proteins and lipids concentration between particles--treated and untreated cells. Comparison between Bhasma-treated and -untreated cells indicates that vibrational peaks corresponding to the DNA/RNA molecule show a significant increase in cells treated with the Jasada Bhasma. Apart from the DNA molecule, several other vibrational peaks related to the protein molecules also show a significant increase in A549 cells after treatment with Bhasma. These results indicate that Bhasma treatment of A549 possibly delays DNA degradation and enables retention of higher amount of protein molecules in the cells.
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Affiliation(s)
- G Pyrgiotakis
- Particle Engineering Research Center, University of Florida, Gainesvilla, Florida, USA
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Abstract
Lactobacillus rhamnosus can metabolize citrate through a citrate inducible transport system. The growth curves of L. rhamnosus on medium containing glucose and citrate was found to be highly dependent on preculturing conditions. It exhibited diauxic growth when precultured on glucose, but demonstrated simultaneous consumption when cultured on citrate. The maximum specific growth rate for cells growing on glucose + citrate was 0.38 h-1, which was higher than the growth rate on individual substrates (0.28 h-1). Simultaneous consumption also yielded higher net flavour compounds, diacetyl and acetoin. Flux analysis indicated that L. rhamnosus requires oxygen for balancing excess NADH through NADH oxidase. The flux analysis provided insights into the metabolic network of L. rhamnosus.
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Affiliation(s)
- B D Jyoti
- Department of Chemical Engineering, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India
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Sahoo S, Verma RK, Suresh AK, Rao KK, Bellare J, Suraishkumar GK. Macro-level and genetic-level responses of Bacillus subtilis to shear stress. Biotechnol Prog 2004; 19:1689-96. [PMID: 14656143 DOI: 10.1021/bp034191w] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [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: 11/29/2022]
Abstract
Responses of bacterial (Bacillus subtilis) cells under different shear levels, from both the macro and genetic viewpoints, have been presented. The responses were studied using a novel, couette flow bioreactor (CFB), in which the entire cultivation can be performed under defined shear conditions. Oxygen supply, the normal limiting factor for entire cultivations under defined shear conditions, has been achieved by passing air through a poly(tetrafluoroethylene) (PTFE) membrane fixed on the inner cylinder of the CFB. More importantly, analyses of the oxygen transfer capabilities as well as the shear rates show that in this CFB, the effects of defined shear can be studied without interference from the effects of oxygen supply. Further, the shake flask can be used as a proper control for studying the shear effects, mainly because the shear rate in the shake flask under normal shaker operating conditions of 190 rpm has been estimated to be a negligible 0.028 s(-1) compared to a value of 445 s(-1) at the lowest rpm employed in the CFB. At the macro level the cell size decreased by almost 50% at 1482 s(-1) compared to that at 0.028 s(-1), the growth rate increased by 245%, and the maximum cell concentration increased by 190% when the shear rate was increased from 0.028 to 1482 s(-1). The specific intracellular catalase level increased by 335% and protease by 87% at 1482 s(-1) as compared to the control cultures at a shear rate 0.028 s(-1). In addition, the specific intracellular reactive oxygen species level (siROS) at the highest shear rate was 9.3-fold compared to the control conditions. At the genetic level we have established the involvement of the transcription factor, sigma(B), in the bacterial responses to shear stress, which was unknown in the literature thus far; the sigma(B) expression correlated inversely with the siROS. Further, through experiments with ROS quenchers, we showed that ROS regulated sigma(B) expression under shear.
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Affiliation(s)
- Susmita Sahoo
- Department of Chemical Engineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400076 India
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Sahoo S, Rao KK, Suresh AK, Suraishkumar GK. Intracellular reactive oxygen species mediate suppression of sporulation inBacillus subtilis under shear stress. Biotechnol Bioeng 2004; 87:81-9. [PMID: 15211491 DOI: 10.1002/bit.20095] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [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: 11/08/2022]
Abstract
Sporulation is an important cellular response to stress that is also significant from a bioreactor operation viewpoint. While sporulating organisms are known to show an enhanced sporulation response under several stress situations, the sporulation response to shear stress has not been investigated thus far. Such a study could be of interest since shear stress, to a greater or lesser degree, is always present in bioreactor operation. In this article, we investigate the sporulation extents of the Gram-positive bacteria Bacillus subtilis at various defined shear levels. We show that, contrary to expectations, shear inhibits sporulation. We found an inverse correlation between the shear rate-dependent specific intracellular reactive oxygen species level (siROS), and the sporulation extent. A 10-fold increase in siROS resulted in about 17-fold decrease in sporulation extent. The involvement of reactive oxygen species (ROS) in sporulation was unknown thus far. Further, through experiments that specifically increased and reduced intracellular ROS (iROS), we established that siROS is responsible for the inhibition of sporulation under shear stress. In addition, we found that shear induced siROS regulated the expression levels of the general stress proteins Ctc and sigma(B). Based on the above, we hypothesize that siROS may regulate suppression of sporulation under high shear by altering sigma(B) and Ctc expression levels, and a model for the same is presented.
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Affiliation(s)
- Susmita Sahoo
- Department of Chemical Engineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
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