Functional morphology of feeding and gill irrigation in the anuran tadpole: electromyography and muscle function in larval Rana catesbeiana

This study provides the first data on muscle activity patterns during active feeding in a larval anuran. Data regarding muscle function during gill irrigation and hyperexpiration are also provided. Electromyographic and kinematic data were recorded from six mandibular and hyoid muscles in unanesthetized, unrestrained larvae of Rana catesbeiana. Only three (hyoangularis, orbitohyoideus, anterior interhyoideus) of the six muscles examined are active during gill irrigation. Feeding cycles are characterized by the recruitment of three additional muscles: intermandibularis, suspensorioangularis, and levator mandibulae longus superficialis. The latter two contribute, respectively, to wide opening and forceful closing of the mouth during feeding. Hyperexpiration is characterized by a reversal of water flow anteriorly out of the mouth. This hydrodynamic change occurs due to modulation of the timing of firing of the anterior interhyoideus, as well as recruitment of the posterior interhyoideus, which is only active during hyperexpiration. Both regions of the interhyoideus, which are responsible for evacuation of the buccal cavity, are active during the opening phase of hyperexpiration. Kinematically, transitioning from gill irrigation to feeding involves both an overall shortening of the gape cycle and a shift in the relative length of opening phase vs. closing phase. Our results corroborate many of the findings of Gradwell ([1972] Can J Zool 50:501-521) regarding muscle function during gill irrigation and hyperexpiration. Furthermore, we demonstrate that in larval anurans the transition from gill irrigation to feeding involves modulation of gape cycle kinematics, changes in the level of activity of muscles, and recruitment of muscles that are not active during irrigation. In light of new data presented here, a review of muscle function in tadpoles is also provided.     

Qualitatively different cross-bridge attachments in fast and slow muscle fiber types

Contractile properties differ between skeletal, cardiac and smooth muscles as well as between various skeletal muscle fiber types. This functional diversity is thought to be mainly related to different speeds of myosin head pulling cycles, with the molecular mechanism of force generation being essentially the same. In this study, force-generating attachments of myosin heads were investigated by applying small perturbations of myosin head pulling cycles in stepwise stretch experiments on skeletal muscle fibers of different type. Slow fibers (frog tonic and rat slow-twitch) exhibited only a ‘slow-type’ of myosin head attachment over the entire activation range, while fast fibers (frog and rat fast-twitch) displayed a ‘slow-type’ of myosin head attachment at low levels of activation, and an up to 30-times faster type at high levels of activation. These observations indicate that there are qualitative differences between the mechanisms of myosin head attachment in slow and fast vertebrate skeletal muscle fibers.     

Spatial fiber type distribution in normal human muscle: Histochemical and tensiomyographical evaluation

The variability of fiber type distribution in nine limb muscles was examined with histochemical and tensiomyographical (TMG) methods in two groups of 15 men aged between 17 and 40 years. The aim of this study was to determine the extent to which the relative occurrence of different fiber types and subtypes varies within human limb muscles in function to depth and to predict fiber type proportions with a non-invasive TMG method.

The distribution of different fiber types varied within the muscles, as a function of depth, with a predominance of type 2b fibers at the surface and type 1 fibers in deeper regions of the muscle. For all the analyzed muscles the contraction times measured at stimulus intensity 10% of supramaximal stimulus (10% MS) were significantly (p<0.05) shorter than the contraction times measured at 50% of supramaximal stimulus intensity (50% MS). The Pearson's correlation coefficient between percentage of type 1 muscle fibers measured at the surface of the muscle and contraction time at 10% MS, obtained by TMG was statistically significant (r=0.76,P<0.01). Also the Pearson's correlation coefficient between percentage of type 1 muscle fibers measured in the deep region of the muscle and contraction time at 50% MS obtained by TMG was also statistically significant (r=0.90,P<0.001).

These findings suggest that the contraction time obtained by TMG may be useful for non-invasive examining of muscle fiber types spatial distribution in humans.     

Isolation and characterization of microsatellite markers in the lowland leopard frog (Rana yavapaiensis) and the relict leopard frog (R. onca), two declining frogs of the North American desert southwest

We characterized 15 microsatellite loci for the lowland leopard frog (Rana yavapaiensis) and the relict leopard frog (R. onca) for future studies of population genetic structure and relatedness. Analysis of 20 individuals from single populations of each species showed that all markers were polymorphic in at least one species. Observed and expected heterozygosities ranged from 0 to 0.94 and from 0.11 to 0.85, respectively, and there were three to 11 alleles per locus. No loci were in linkage disequilibrium, but six loci deviated significantly from Hardy-Weinberg equilibrium, and the presence of a null allele was detected in two of these loci.     

The claw closer muscle of two estuarine crab species,Cyrtograpsus angulatus and Neohelice granulata (Grapsoidea,Varunidae): histochemical fibre type composition

Longo, M.V. and Díaz, A.O. (2011). The claw closer muscle of two estuarine crab species, Cyrtograpsus angulatus and Neohelice granulata (Grapsoidea, Varunidae): histochemical fibre type composition. —Acta Zoologica (Stockholm) 00 : 1–7. This study permitted the characterization of four types of muscle fibres in the claw closer muscles of Cyrtograpsus angulatus and Neohelice granulata. Succinic dehydrogenase (SDH) for mitochondria, periodic acid Schiff (PAS) for glycogen, Sudan Black B for lipids and myosin‐adenosine triphosphatase (m‐ATPase) preincubated at alkaline and acid pHs were used for that purpose. The mean fibre diameters, the relative areas and frequencies of each muscle fibre type were calculated. Types I and IV would be considered ‘extreme’ groups with type I fibres large, weak and acid/alkaline‐labile m‐ATPase, weak SDH, PAS and Sudan, and type IV fibres small, very strong and acid/alkaline‐resistant m‐ATPase, strong SDH and PAS, and moderate Sudan. Types II and III would belong to a predominant ‘intermediate’ group. Type IV fibres were scarce in C. angulatus but represented 25% of the total fibre population in N. granulata. In C. angulatus, the relative area occupied by type I fibres was bigger than its relative proportion, whereas in N. granulata, types I and II had similar patterns. Concluding, variations in fibre type composition in the claw closer muscles of C. angulatus and N. granulata would be linked to different habitats and feeding behaviours.     

Macromolecular and enzymatic abnormalities induced by a synthetic pyrethroid,Ripcord (Cypermethrin), in adult beetles of a stored grain pest,Tribolium castaneum (Herbst.) (Coleoptera: Tenebrionidae)

The effects of a synthetic pyrethroid insecticide, cypermethrin, administered as a formulation Ripcord 25EC (emulsified concentrate), to adult beetles of a stored grain pest, Tribolium castaneum, have been studied, with an objective to ascertain its toxicity on enzymes such as carbohydrases, phosphatases, dehydrogenases, aminotransferases, and concentration of various biochemical components such as monosaccharides, glycogen, cholesterol, nucleic acids, urea, total lipids, and total proteins. Almost all the enzymes and biochemical components were sensitive to sublethal doses of Ripcord 25 EC and these effects were found to be dependent on the duration of treatment. All carbohydrate metabolizing enzymes (amylase, invertase, lactase, maltase, lactate dehydrogenase) were elevated, except for trehalase, which was also elevated up to day 3 but returned to normal levels subsequently. Phosphatases (alkaline as well as acidic) were increased first and decreased thereafter, while isocitrate dehydrogenase decreased throughout the experimental period. Transaminases (aspartate aminotransferase and alanine aminotransferase) showed a decreasing trend. Of the other biochemical components tested, glucose content decreased during the first 3 days but increased subsequently. Fructose content showed an increase, while the glycogen content decreased throughout the study. Total lipid content was not disturbed up to day 3 but increased thereafter. Cholesterol content was depleted by day 7. Total proteins started decreasing from day 3 onwards, while soluble proteins were not affected. DNA, RNA, and urea contents exhibited elevated levels, while uric acid showed a decreasing trend. Sublethal doses of Ripcord, therefore, resulted in extensive enzyme induction, and utilization of carbohydrates, proteins, and lipids, in the given order, perhaps to produce extra energy to combat insecticidal stress. Arch. Insect Biochem. Physiol. 39:144–154, 1998. © 1998 Wiley-Liss, Inc.     

Morphological changes of skeletal muscle, tendon and periosteum in the senescence-accelerated mouse (SAMP6): a murine model for senile osteoporosis

SAMP6, a substrain of senescence-accelerated mouse, was developed as an animal model for senile osteoporosis. Previously we observed age-related changes of the bone in SAMP6. In the present study, we investigated the morphology of the skeletal muscle, tendon and periosteum in SAMP6 and age-matched normal mouse SAMR1. We did not find any significant differences between SAMR1 and SAMP6 at 1 and 2 months of age. As compared with SAMR1, the cross-sectional area of type I and type II muscle fibers of the soleus muscle were significantly low in SAMP6 at 8 months of age. The projections in the interface of the muscle-tendon junctions were significantly decreased in SAMP6 at 8 months of age. The number of fibroblasts and the diameter of the tendon collagen fibers in Achilles fiber were significantly reduced in SAMP6 at 8 months of age. The diameter of Sharpey's fiber reduced in SAMP6 at 5 and 8 months of age. Some chondrocytes in the insertions of Achilles tendon and some osteogenic cells in the periosteum showed degenerative changes in SAMP6 at 5 and 8 months of age. The pronounced degenerative changes were detected in the skeletal muscle, muscle-tendon junction, tendon, tendon-bone interface and periosteum in SAMP6 with age. These findings indicated the atrophy of skeletal muscle, degeneration of tendon and periosteum in SAMP6, which may be involved in the bone loss for senile osteoporosis.     

不同日龄和吊飞过程中桔小实蝇成虫飞行肌能量代谢相关酶活性的变化

【目的】明确桔小实蝇Bactrocera dorsalis(Hendel)飞行肌对能源物质的利用。【方法】通过生化方法测定了能源物质代谢相关5种酶[3-磷酸甘油醛脱氢酶(GAPDH)、3-磷酸甘油脱氢酶(GDH)、乳酸脱氢酶(LDH)、柠檬酸合酶(CS)和3-羟酰辅酶A脱氢酶(HOAD)]活性的变化。【结果】桔小实蝇成虫中所测的5种酶活性随日龄的变化而变化,4日龄GAPDH,GDH,LDH和CS活性最高,20日龄HOAD活性最高。吊飞过程中,GAPDH,GDH和CS的活性变化基本一致,随吊飞时间的延长活性逐渐升高;LDH和HOAD的活性变化雌、雄虫完全不同。雄虫LDH活性除吊飞2 h外其他时间均高于静息状态,雌虫则始终低于静息状态;雄虫HOAD活性只有吊飞24 h低于静息状态水平,而雌虫吊飞后HOAD活性一直在静息状态水平及以下波动。【结论】桔小实蝇飞行所利用的能源物质包括糖类和脂肪,以糖类能源为主。吊飞过程中,雄虫除可以进行高速有氧代谢以外,还具备一定的无氧代谢能力,而雌虫只进行有氧代谢;雄虫能利用脂肪供给能量,雌虫则几乎不动用脂肪。研究结果为进一步阐明桔小实蝇的迁飞行为机制提供了依据。     

Thyrotropin Releasing Hormone (TRH) in goldfish (Carassius auratus): role in the regulation of feeding and locomotor behaviors and interactions with the orexin system and cocaine- and amphetamine regulated transcript (CART)

TRH is a peptide produced by the hypothalamus which major function in mammals is the regulation of TSH secretion by the pituitary. In fish, TRH does not appear to affect TSH secretion, suggesting that it might regulate other functions. In this study, we assessed the effects of central (intracerebroventricular, icv) injections of TRH on feeding and locomotor behavior in goldfish. TRH at 10 and 100 ng/g, but not 1 ng/g, significantly increased feeding and locomotor behaviors, as indicated by an increase in food intake and in the number of total feeding acts as compared to saline-injected fish. In order to assess possible interactions between TRH and other appetite regulators, we examined the effects of icv injections of TRH on the hypothalamic expression of orexin, orexin receptor and CART. The mRNA expression levels of all three peptides were significantly increased in fish injected with TRH at 100 ng/g as compared to saline-injected fish. Fasting increased TRH, orexin, and orexin receptor hypothalamic mRNA levels and decreased CART hypothalamic mRNA levels. Our results suggest that TRH is involved in the regulation of feeding/locomotor activity in goldfish and that this action is associated with a stimulation of both the orexin and CART systems.     

Effect of different conditioning treatments on total phenolic content and antioxidant activities in two Sargassacean species: Comparison of the frondose Sargassum muticum (Yendo) Fensholt and the cylindrical Bifurcaria bifurcata R. Ross

The effects of different conditioning treatments (fresh, freezing, freeze‐drying, oven‐drying and greenhouse‐drying) on the total phenolic content (TPC) and antioxidant activities of two brown algae, Sargassum muticum and Bifurcaria bifurcata, were investigated and compared. Phenolic compounds were extracted in a methanol/water (50:50) solution, and TPC was measured by the colorimetric Folin‐Ciocalteu assay. Antioxidant activity was assessed by the DPPH (2, 2‐diphenyl‐1‐picrylhydrazyl) radical scavenging assay and the β‐carotene bleaching method. The dried seaweeds showed lower phenolic contents and lower antioxidant capacities than the fresh and frozen ones, which suggests that the phenolic content and antioxidant activities are decreased by the drying treatments, especially, oven‐ and greenhouse‐drying. Relationships between TPC, antioxidant properties and conditioning treatments are discussed.     

Decontamination of heart valve and arterial allografts in the European Homograft Bank (EHB): comparison of two different antibiotic cocktails in low temperature conditions

The aim of the study was to compare the efficiency of two different antibiotic cocktails in the cardiovascular allograft decontamination. Low temperature, low-concentration antibiotic cocktail with Cefoxitin, Lincomycin, Polymixin B and Vancomycin was decontamination protocol in EHB for many years. The modified cocktail doesn't contain Cefoxitin. The study had two steps. First step: cardiovascular allografts from 80 donors are incubated in classical (group 1) or modified cocktail (group 2). Second step: 184 and 182 allografts of group 1 and group 2 are incubated in the modified and classical antibiotic cocktail, respectively. The bacteriological examination is performed in three steps: A-transport solution, B-decontamination solution and C-cryopreservation solution. During the first step 23.75% of the tissues were initially contaminated mainly with Staphylococcus (78.95%). 93.75% of the allografts of group 1 and 100% of group 2 were sterile after incubation (p = 0.058). 25.54% and 30.77% of group 1 and 2, respectively were contaminated in A-examination during the second step. Staphylococci were isolated in 82.98% and 69.64% in group 1 and 2, respectively. About 4.35% of group 1 and 5.5% of group 2 were contaminated in A, B, and C whereas 5.4% of group 1 and 4.4% of group 2 were contaminated in B or C after being sterile in A. Finally 9.78% of the tissues were rejected and 90.22% cryopreserved in the modified, whereas 9.89% rejected and 90.11% accepted in the classical group (p = 0.1). The difference was non-significant in the level of decontamination between the two cocktails. Contamination of some tissues with low growing, low-pathogen germs that appeared in B or C examination, couldn't be explained. This issue needs complementary investigation.     

Characterization of sarcolemma and sarcoplasmic reticulum isolated from skeletal muscle of the freeze tolerant wood frog, Rana sylvatica: the beta(2)-adrenergic receptor and calcium transport systems in control, frozen and thawed states

In freeze tolerant wood frog Rana sylvatica, the freeze-induced liberation of glucose plays a critical role in survival in response to sub-zero temperature exposure. We have shown that the glycaemic response is linked to selective changes in the expression of hepatic adrenergic receptors through which catecholamines act to produce their hepatic glycogenolytic effects. The purpose of the present study was to determine if skeletal muscle, another catecholamine-sensitive tissue with glycogenolytic potential, displayed similar or different changes. In order to achieve these objectives, skeletal muscle derived from Rana sylvatica was studied in control, frozen and thawed states. In isolated sarcolemmal fractions, freezing effected an 88% decrease in beta(2)-adrenergic receptor expression but was without effect on the calcium pump; while thawing resulted in a recovery of the beta(2)-adrenergic receptor to 60% of control levels and a 2.4-fold increase in calcium transport. In isolated sarcoplasmic reticular fractions, freezing effected a 52% decrease in calcium binding and a 92% decrease in oxalate-stimulated calcium uptake; while thawing elicited partial normalization to control levels to 70% with respect to calcium binding and to 47% with respect to calcium uptake. Freezing and thawing were associated with increases and decreases, receptively, in blood glucose levels but were without effect on skeletal muscle glycogen content. Thus these muscle changes in Rana sylvatica in freezing and thawing are not linked to glycogen breakdown, are different from those previously seen in liver, and may provide a role in recovery of muscle function during thawing by protecting glycogen stores for contraction and maximizing extracellular calcium for excitation-contraction coupling in the frozen state. The involvement of thyroid hormone in triggering these muscle changes is discussed.     

Life history and secondary production of Glossosoma nigrior Banks (Trichoptera: Glossosomatidae) in two Alabama streams with different geology

We studied life history and secondary production of a caddisfly scraper, Glossosoma nigrior, in two Alabama streams. Collier Creek, located within the Appalachian Plateau physiographic province, is underlain by sandstone bedrock, while Hendrick Mill Branch is located in the Valley and Ridge physiographic province with limestone bedrock. G. nigrior populations in both streams exhibited trivoltine life histories, which were attributed to the higher water temperature regimes than those found in more northern streams. Mean larval density (556 m⁻²) and biomass (B) (49.2 mg AFDM m⁻²) were much higher in Hendrick Mill Branch than Collier Creek (78 m⁻² and 6.7 mg AFDM m⁻²). G. nigrior in Hendrick Mill Branch maintained continuous larval growth and higher larval density than Collier Creek throughout the year mainly due to a greater availability of optimal habitat, a more stable hydrology, and warmer winter water temperature. These factors also resulted in the much higher annual secondary production (P) in Hendrick Mill Branch (965 mg AFDM m⁻²; P/B = 18.3) than Collier Creek (115 mg AFDM m⁻²; P/B = 17.9). Gut content analysis revealed that algae (>50%) and detritus (>40%) were the major diet items for G. nigrior, and the majority of secondary production (>80%) was contributed by the consumption of algae. Glossosoma populations play an important role in trophic linkage in these streams with their high production and grazing activities. Handling editor: D. Dudgeon     

A comparison of avoidance to acoustic stimuli in fish with different auditory capabilities: juvenile chum salmon (Oncorhynchus keta) and common carp (Cyprinus carpio)

This study compared the repulsive effects of sound playbacks of intermittent 30, 150, 300, 600 and 900 Hz tones on two fish with different auditory capabilities: juvenile chum salmon (Oncorhynchus keta) and common carp (Cyprinus carpio). When 150 and 300 Hz tones were emitted from an underwater speaker, O. keta exhibited a moderate repulse reaction. Conversely, C. carpio exhibited a moderate repulse reaction to a tone with a frequency of 30 Hz, which indicates that a low-frequency component in complex broadband sound may be important for inducing a repulse reaction in cyprinids.