Morphology and Electrochemistry of Insect Muscle Fibre Membrane

Piek, T.; Njio, K.D.

doi:10.1016/s0065-2806(08)60053-3

Cited by 18 publications

(2 citation statements)

References 177 publications

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“…Many of the 20 upregulated pathways were involved in signaling, and most of the 47 downregulated pathways related to metabolism. The ‘cardiac muscle contraction’ pathway (appropriate to insect striated muscle, [ 79 ]) was downregulated based on reduced expression of a cytochrome c reductase gene. Unlike in the hindgut, NKA, tropomyosin, or myosin heavy chain components of this pathway were not upregulated in Malpighian tubules.…”

Section: Resultsmentioning

confidence: 99%

Effects of cold-acclimation on gene expression in Fall field cricket (Gryllus pennsylvanicus) ionoregulatory tissues

et al. 2017

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BackgroundCold tolerance is a key determinant of temperate insect distribution and performance. Chill-susceptible insects lose ion and water homeostasis during cold exposure, but prior cold acclimation improves both cold tolerance and defense of homeostasis. The mechanisms underlying these processes are mostly unknown; cold acclimation is thought to enhance ion transport in the cold and/or prevent leak of water and ions. To identify candidate mechanisms of cold tolerance plasticity we generated transcriptomes of ionoregulatory tissues (hindgut and Malpighian tubules) from Gryllus pennsylvanicus crickets and compared gene expression in warm- and cold-acclimated individuals.ResultsWe assembled a G. pennsylvanicus transcriptome de novo from 286 million 50-bp reads, yielding 70,037 contigs (~44% of which had putative BLAST identities). We compared the transcriptomes of warm- and cold-acclimated hindguts and Malpighian tubules. Cold acclimation led to a ≥ 2-fold change in the expression of 1493 hindgut genes (733 downregulated, 760 upregulated) and 2008 Malpighian tubule genes (1009 downregulated, 999 upregulated). Cold-acclimated crickets had altered expression of genes putatively associated with ion and water balance, including: a downregulation of V-ATPase and carbonic anhydrase in the Malpighian tubules and an upregulation of Na+-K+ ATPase in the hindgut. We also observed acclimation-related shifts in the expression of cytoskeletal genes in the hindgut, including actin and actin-anchoring/stabilizing proteins, tubulin, α-actinin, and genes involved in adherens junctions organization. In both tissues, cold acclimation led to differential expression of genes encoding cytochrome P450s, glutathione-S-transferases, apoptosis factors, DNA repair, and heat shock proteins.ConclusionsThis is the first G. pennsylvanicus transcriptome, and our tissue-specific approach yielded new candidate mechanisms of cold tolerance plasticity. Cold acclimation may reduce loss of hemolymph volume in the cold by 1) decreasing primary urine production via reduced expression of carbonic anhydrase and V-ATPase in the Malpighian tubules and 2) by increasing Na+ (and therefore water) reabsorption across the hindgut via increase in Na+-K+ ATPase expression. Cold acclimation may reduce chilling injury by remodeling and stabilizing the hindgut epithelial cytoskeleton and cell-to-cell junctions, and by increasing the expression of genes involved in DNA repair, detoxification, and protein chaperones.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3711-9) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Effects of cold-acclimation on gene expression in Fall field cricket (Gryllus pennsylvanicus) ionoregulatory tissues

et al. 2017

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“…K + and Cl~ are responsible for the resting membrane permeability of locust skeletal muscle. The concentration gradients of these ions are maintained by metabolic pumps (Usherwood, 1967(Usherwood, , 1969Piek and Njio, 1979;Pichon and Ashcroft, 1985;Leech, 1986). Depolarisation of the locust muscle fibre leads to a voltage-dependent increase in the Na + permeability, possibly accompanied by an increase in Ca 2+ permeability and a delayed increase in K + permeability (Usherwood, 1969).…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Five Types of K+ Channel in Cultured Locust Muscle

Miller

Usherwood

1990

Journal of Experimental Biology

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K+ channel activity in cultured locust myofibres was investigated using gigaohm patch-clamp techniques. After 2 months in vitro the myofibres had a mean resting potential of −39 ± 7 mV (±S.D., 7V = 42). Five types of K+ channel were identified at this time. The majority of single-channel events recorded from cellattached patches were due to a small-conductance (type 1) and a largeconductance (type 2), inward rectifier, K+ channel. In cell-attached patches, with 180 mmoll−1 KC1 in the patch pipette, the type 1 channel had a chord conductance of 43 pS for inward currents and 8pS for outward currents; the type 2 channel had a chord conductance of 115 pS for inward currents and 29 pS for outward currents. The type 2 channel exhibited bursting kinetics, was ATP-sensitive and could be blocked by Ba2+. Two other channels (types 3 and 4) had linear conductances of 130pS and 207pS, respectively. The type 3 channel was Ca2+-sensitive. A further channel (type 5) appeared to be an inward rectifier with a conductance of 5pS. Openings of types 3, 4 and 5 channels occurred less frequently than openings of the other two channels. Types 1, 2, 3 and 4 channels possessed multiple closed and open states with non-linear gating mechanisms.

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The effect of external cesium ions on the muscle fibre resting potential in mealworm larva (Tenebrio molitor L.)

Katkowska¹

1995

J Comp Physiol A

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The membrane potential of ventral longitudinal muscles of Tenebrio molitor larvae was studied as a function of time and of cesium substituted for all or part of external potassium. The conventional microelectrode technique was applied. The mean value of resting potential was -47.4 mV in standard physiological saline which did not change significantly with time (90 min). Cesium caused, almost immediately, a significant hyperpolarization of membrane potential the magnitude of which depended on cesium concentration. The presence of external potassium enhanced the effectiveness of cesium action, resulting in more pronounced hyperpolarization. The effect of Cs ions was fully reversible upon washing. These data support the idea that inward potassium current can be activated at resting potential level, at least in some cells, including the muscles studied. It is presumed that this potassium current might have some contribution to the resting membrane potential generation in mealworm larva muscles. Key words Cesium 9 Membrane potential 9 Blocking of potassium inward current 9 Insect muscle Abbreviations [K § extracellular concentration of K ions 9 E,, resting membrane potential of a cell when bathed in normal saline 9 EKK + equilibrium potential -MP membrane potential 9 RP resting potential -SD standard deviation 9 SEM standard error of the mean

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Morphology and Electrochemistry of Insect Muscle Fibre Membrane

Cited by 18 publications

References 177 publications

Effects of cold-acclimation on gene expression in Fall field cricket (Gryllus pennsylvanicus) ionoregulatory tissues

Effects of cold-acclimation on gene expression in Fall field cricket (Gryllus pennsylvanicus) ionoregulatory tissues

Characteristics of Five Types of K+ Channel in Cultured Locust Muscle

The effect of external cesium ions on the muscle fibre resting potential in mealworm larva (Tenebrio molitor L.)

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