Trends in the Changes of Postgonite Forms during the Evolution of Grass Flies of the Genus Meromyza (Diptera,Chloropidae)

Biology Bulletin - Grass flies of the genus Meromyza have been grouped by the COI mtDNA locus into several clusters, which corresponds to the morphological characteristics of the anterior processes...     

Contributions to the knowledge of European species of the genus <Emphasis Type="Italic">Meromyza</Emphasis> (Diptera,Chloropidae)

Meromyza filippovi sp. n. is described from the European part of Turkey [TURKEY: Sariyer, Buyukdere (41.163852°N, 29.042238°E), 19.VIII.1938, coll. Zhenzhurist (= N.N. Filippov)]. The holotype of the new species is deposited at the Zoological Museum of Moscow State University.     

Damage to marram grass Ammophila arenaria by larvae of Meromyza pratorum (Diptera)

Larvae of Meromyza pratorum Meigen (Diptera, Chloropidae) were found to affect tillers of Ammophila arenaria (L.) Link in the dunes of Newborough Warren. Anglesey, U.K. The highest percentages of affected tillers were found in September. There were clear differences between the proportions of affected tillers in the various successional stages of the dunes. It was found that the proportion of affected tillers was reduced by a fertilizer treatment but slightly increased by removing associated species.     

Grass Flies (Diptera,Chloropidae) of Crimean Peninsula

The fauna of grass flies (Diptera: Chloropidae) of the Crimean Peninsula is reviewed for the first time. The study is based on examination of the collection of the Zoological Institute, Russian Academy of Sciences (St. Petersburg), which includes the material collected in Crimea by the authors, the collections of the Zoological Museum of the M. V. Lomonosov Moscow State University and V. I. Vernadsky Crimean Federal University (Simferopol). The annotated list includes 92 species in 34 genera and three subfamilies. Most of the species (61) are recorded from Crimea for the first time. Six species, Chlorops horridus Becker, Ch. puncticornis Loew, Dicraeus (Oedesiella) beschovskii Nartshuk, Lasiosina chandleri Ismay, Meromyza meigeni Nartshuk and Oscinimorpha longirostris (Loew) are recorded for the first time from Russia and Eastern Europe. The characters for distinguishing Oscinimorpha arcuata Duda from O. longirostris (Loew), i.e., the structure of head and the male genitalia, are provided. The boreo-montane species Oscinella vastator (Curtis) and Meromyza curvinervis (Zetterstedt) are found on the Chatyrdag Mountain and Yaila (mostly forestless plateau in the Crimean Mountains). Species with southern European, Mediterranean and Macaronesian-Mediterranean ranges were recorded mostly on the South Coast of Crimea. The Crimean fauna of Chloropidae is compared with the faunas of Sardinia and Turkey.     

THE FRIT FLY AND ALLIED STEM-BORING DIPTERA IN WINTER WHEAT AND HOST GRASSES

Sampling for stem-boring larvae was undertaken in 1954-56 on ley plots of Lolium perenne, Dactylis glomerata, Festuca arundinacea, F. rubra, Agrostis tenuis and Poa pratensis in randomized experiments at Hurley, Berks. The samples showed infestations by dipterous larvae, mainly species of Oscinella, Meromyza and Opomyza. The larvae showed preferences for specific grass hosts. More larvae were found where plots had been grazed throughout the season than where an early hay cut had preceded grazing. The total numbers of larvae varied between o and 688 per sq.yd. in November.
The larval populations of the leys were reflected in the populations in winter wheat which followed the plough-up of the leys. Populations of up to sixty-five larvae per sq.yd., mostly species of Oscinella , were found in the wheat in March. In 1956 a heavy larval infestation was associated with the death of considerable numbers of wheat plants.     

Morphometric and Molecular Diversity of the Holarctic <Emphasis Type="Italic">Meromyza saltatrix</Emphasis> (L., 1761) (Diptera,Chloropidae) in Eurasia

The population diversity of the frit fly Meromyza saltatrix from Poland, Mongolia, and several regions of the Russian Federation was analyzed by morphometric and molecular data on the mtDNA locus COI. Two phenotypes that correspond to two haplogroups (19 haplotypes) were identified by the absence or presence of black setae on the lower surface of the genae. A remarkable clinal variability among populations was demonstrated by the total area and area of the projecting part of the anterior processes of postgonites (APP), which play a critical role in the success of male copulation. Each parameter analyzed divided populations into four groups. Close populations with a natural barrier vary in the total area of the anterior process of the postgonite. We found an increased number of mutations including transversions in frit flies from Mongolia. Populations from Zvenigorod, South Ural Nature Reserve, and Mongolia might be of a later origin. The presence of particular haplogroup in the West European population of M. saltatrix with black setae, which is a unique feature of West European species of Meromyza, and their similarity to the Crimean population by the morphometrics of the APP is an indication of the possible isolation of this population in southern Europe during Quaternary glaciations with subsequent expansion to the northern part of the geographical area.     

The acute effects of mechanical vibration on power output in the bench press

This study was designed to investigate the effect of mechanical vibration on acute power output in the bench press exercise. Ten male subjects who were experienced in resistance training participated in this study. Each subject performed 3 sets of 3 repetitions in the bench press exercise using a load equal to 70% of 1 repetition maximum in each of 2 sessions separated by 3 days. One session served as the experimental (vibration) condition, whereas the other session served as the control (no vibration) condition. The intervention (vibration or control) was applied between sets 2 and 3. The vibration was applied by a vibrating barbell apparatus held by the subjects while lying supine on a bench. The only difference between the 2 conditions was the vibration of the barbell apparatus during the vibration condition. Peak and average power were calculated during each bench press set to determine whether power output differed following vibration compared to control. Average power was significantly higher for the vibration condition compared to the control (525 +/- 74 vs. 499 +/- 71 W; p = 0.01). There was also a trend toward an increase in peak power in the vibration condition (846 +/- 168 by vs. 799 +/- 149 W; p = 0.06). In general, peak and average power output were higher following the vibration intervention compared to control. However, the sets prior to vibration application during the vibration condition also demonstrated higher power outputs compared with the control condition, which contributed to the main effect for the vibration condition. These results suggest that factors other than the vibration intervention influenced task performance during the vibration condition. We suggest that psychological factors related to the novelty of the vibration intervention were involved. These factors may partially explain the conflicting results of previous investigations that examined vibration as an exercise intervention.     

Reductions in finger blood flow in men and women induced by 125-Hz vibration: association with vibration perception thresholds

Vibration of one hand reduces blood flow in the exposed hand and in the contralateral hand not exposed to vibration, but the mechanisms involved are not understood. This study investigated whether vibration-induced reductions in finger blood flow are associated with vibrotactile perception thresholds mediated by the Pacinian channel and considered sex differences in both vibration thresholds and vibration-induced changes in digital circulation. With force and vibration applied to the thenar eminence of the right hand, finger blood flow and finger skin temperature were measured in the middle fingers of both hands at 30-s intervals during seven successive 4-min periods: 1) pre-exposure with no force or vibration, 2) pre-exposure with force, 3) vibration 1, 4) rest with force, 5) vibration 2, 6) postexposure with force, and 7) recovery with no force or vibration. A 2-N force was applied during periods 2-6 and 125-Hz vibration at 0.5 and 1.5 ms(-2) root mean square (r.m.s.; unweighted) was applied during periods 3 and 5, respectively. Vibrotactile thresholds were measured at the thenar eminence of right hand using the same force, contact conditions, and vibration frequency. When the vibration magnitude was greater than individual vibration thresholds, changes in finger blood flow were correlated with thresholds (with both 0.5 and 1.5 ms(-2) r.m.s. vibration): subjects with lower thresholds showed greater reductions in finger blood flow. Women had lower vibrotactile thresholds and showed greater vibration-induced reductions in finger blood flow. It is concluded that mechanoreceptors responsible for mediating vibration perception are involved in the vascular response to vibration.     

Vibration training: an overview of the area, training consequences, and future considerations

The effects of vibration on the human body have been documented for many years. Recently, the use of vibration for improving the training regimes of athletes has been investigated. Vibration has been used during strength-training movements such as elbow flexion, and vibration has also been applied to the entire body by having subjects stand on vibration platforms. Exposure to whole-body vibration has also resulted in a significant improvement in power output in the postvibratory period and has been demonstrated to induce significant changes in the resting hormonal profiles of men. In addition to the potential training effects of vibration, the improvement in power output that is observed in the postvibratory period may also lead to better warm-up protocols for athletes competing in sporting events that require high amounts of power output. These observations provide the possibility of new and improved methods of augmenting the training and performance of athletes through the use vibration training. Despite the potential benefits of vibration training, there is substantial evidence regarding the negative effects of vibration on the human body. In conclusion, the potential of vibration treatment to enhance the training regimes of athletes appears quite promising. It is essential though that a thorough understanding of the implications of this type of treatment be acquired prior to its use in athletic situations. Future research should be done with the aim of understanding the biological effects of vibration on muscle performance and also the effects of different vibration protocols on muscle performance.     

The apparent mass of the seated human exposed to single-axis and multi-axis whole-body vibration

Most workplaces where workers are exposed to whole-body vibration involves simultaneous motion in the fore-and-aft (x-), lateral (y-) and vertical (z-) directions. Previous studies reporting the biomechanical response of people exposed to vibration have almost always used single-axis vibration stimuli. This paper reports a study where apparent masses of 15 subjects were measured whilst exposed to single-axis and tri-axial whole-body vibration. Each subject was exposed to 28 vibration conditions comprising every combination of single-axis and tri-axial vibration with magnitudes of 0.4 and 0.8 ms(-2) r.m.s. in each direction, once with backrest contact and once without backrest contact. Results show that increasing the magnitude of vibration in directions orthogonal to that being measured affects the apparent mass, causing a reduction in the resonance frequency as the total magnitude of vibration increases. It is demonstrated that the apparent mass resonance frequency is a function of the total vibration magnitude in all axes rather than a function of the vibration magnitude in the direction being measured. It is also shown that, for individuals, the frequency of the peak in the apparent mass in one direction is not related to the frequency of the peak in another direction. It is concluded that more complex biomechanical models are required in order to simulate human response to multi-axis vibration.     

Reduction of Saccharomyces cell adhesion by liquid mechanical vibration

The effect of liquid mechanical vibration on the adhesion of Saccharomyces cerevisiae cells to the internal glass surface of a pipette was studied using a 25 Hz vibration source. The maximum vibration amplitude was 1.06 mm (peak to peak) along the pipette direction. Relative movements between the pipette and yeast suspension in it were produced by vibration and reduced the cell adhesion. The reduction in adhesion was affected by both vibration amplitude and suspension pH. Analysis showed that in routine cell counts, cell adhesion to the pipette wall was a significant error source. The construction of a vibration device for routine cell count work appears feasible.     

Changes in EMG activity in the upper trapezius muscle due to local vibration exposure

Exposure to vibration is suggested as a risk factor for developing neck and shoulder disorders in working life. Mechanical vibration applied to a muscle belly or a tendon can elicit a reflex muscle contraction, also called tonic vibration reflex, but the mechanisms behind how vibration could cause musculoskeletal disorders has not yet been described. One suggestion has been that the vibration causes muscular fatigue. This study investigates whether vibration exposure changes the development of muscular fatigue in the trapezius muscle. Thirty-seven volunteers (men and women) performed a sub-maximal isometric shoulder elevation for 3 min. This was repeated four times, two times with induced vibration and two times without. Muscle activity was measured before and after each 3-min period to look at changes in the electromyography parameters. The result showed a significantly smaller mean frequency decrease when performing the shoulder elevation with vibration (?2.51 Hz) compared to without vibration (?4.04 Hz). There was also a slightly higher increase in the root mean square when exposed to vibration (5.7% of maximal voluntary contraction) compared to without (3.8% of maximal voluntary contraction); however, this was not statistically significant. The results of the present study indicate that short-time exposure to vibration has no negative acute effects on the fatiguing of upper trapezius muscle.     

Vibration communication in orthopteroid insects (Orthoptera) from suborder Caelifera

A review of vibration communication in suborder Caelifera is made. The vibration communication channel is found in three superfamilies—Tetrigoidea, Eumastacoidea and Acridoidea. The presence of vibration communication in Pyrgomorphoidea and Tridactyloidea is suggested. The data on vibration signals in superfamilies Pneumoroidea, Tanaoceroidea and Trigonopterygoidea are not known.     

The effects of muscle vibration on gait control: a review

Abstract

Background: The purpose of the review is to summarize the literature surrounding the use of muscle vibration as it relates to modifying human gait.

Methods: After a brief introduction concerning historical uses and early research identifying the effect of vibration on muscle activation, we reviewed 32 articles that used muscle vibration during walking. The review is structured to address the literature within four broad categories: the effect of vibration to ‘trigger’ gait-like lower limb motions, the effect of vibration on gait control of healthy individuals and individuals with clinical conditions in which gait disorders are a prominent feature, and the effect of vibration training protocols on gait.

Results: The acute effects of vibration during gait involving healthy participants is varied. Some authors reported differences in segmental kinematic and spatiotemporal measures while other authors reported no differences in these outcome measures. The literature involving participants with clinical conditions revealed that vibration consistently had a significant impact on gait, suggesting vibration may be an effective rehabilitation tool. All of the studies that used vibration therapy over time reported significant improvement in gait performance.

Conclusions: This review highlights the difficulties in drawing definitive conclusions as to the impact of vibration on gait control, partly because of differences in walking protocols, site of vibration application, and outcome measures used across different investigative teams. It is suggested that the development of common investigative methodologies and outcome measures would accelerate the identification of techniques that may provide optimal rehabilitation protocols for individuals experiencing disordered gait control.     

Human postural responses to different frequency vibrations of lower leg muscles

We analyzed human postural responses to muscle vibration applied at four different frequencies to lower leg muscles, the lateral gastrocnemius (GA) or tibialis anterior (TA) muscles. The muscle vibrations induced changes in postural orientation characterized by the center of pressure (CoP) on the force platform surface on which the subjects were standing. Unilateral vibratory stimulation of TA induced body leaning forward and in the direction of the stimulated leg. Unilateral vibration of GA muscles induced body tilting backwards and in the opposite direction of the stimulated leg. The time course of postural responses was similar and started within 1 s after the onset of vibration by a gradual body tilt. When a new slope of the body position was reached, oscillations of body alignment occurred. When the vibrations were discontinued, this was followed by rapid recovery of the initial body position. The relationship between the magnitude of the postural response and frequency of vibration differed between TA and GA. While the magnitude of postural responses to TA vibration increased approximately linearly in the 60-100 Hz range of vibration frequency, the magnitude of response to GA vibration increased linearly only at lower frequencies of 40-60 Hz. The direction of body tilt induced by muscle vibration did not depend on the vibration frequency.     

Relevance of motion artifact in electromyography recordings during vibration treatment

Electromyography readings (EMGs) from quadriceps of fifteen subjects were recorded during whole body vibration treatment at different frequencies (10–50 Hz). Additional electrodes were placed on the patella to monitor the occurrence of motion artifact, triaxial accelerometers were placed onto quadriceps to monitor motion. Signal spectra revealed sharp peaks corresponding to vibration frequency and its harmonics, in accordance with the accelerometer data. EMG total power was compared to that associated with vibration harmonics narrow bands, before and during vibration. On average, vibration associated power resulted in only 3% (±0.9%) of the total power prior to vibration and 29% (±13.4%) during vibration. Often, studies employ surface EMG to quantitatively evaluate vibration evoked muscular activity and to set stimulation frequency. However, previous research has not accounted for motion artifacts. The data presented in this study emphasize the need for the removal of motion artifacts, as they consistently affect RMS estimation, which is often used as a concise muscle activity index during vibrations. Such artifacts, rather unpredictable in amplitude, might be the cause of large inter-study differences and must be eliminated before analysis. Motion artifact filtering will contribute to thorough and precise interpretation of neuromuscular response to vibration treatment.     

Effect of chest wall vibration on breathlessness in normal subjects

This study evaluated the effect of chest wall vibration (115 Hz) on breathlessness. Breathlessness was induced in normal subjects by a combination of hypercapnia and an inspiratory resistive load; both minute ventilation and end-tidal CO2 were kept constant. Cross-modality matching was used to rate breathlessness. Ratings during intercostal vibration were expressed as a percentage of ratings during the control condition (either deltoid vibration or no vibration). To evaluate their potential contribution to any changes in breathlessness, we assessed several aspects of ventilation, including chest wall configuration, functional residual capacity (FRC), and the ventilatory response to steady-state hypercapnia. Intercostal vibration reduced breathlessness ratings by 6.5 +/- 5.7% compared with deltoid vibration (P less than 0.05) and by 7.0 +/- 8.3% compared with no vibration (P less than 0.05). The reduction in breathlessness was accompanied by either no change or negligible change in minute ventilation, tidal volume, frequency, duty cycle, compartmental ventilation, FRC, and the steady-state hypercapnic response. We conclude that chest wall vibration reduces breathlessness and speculate that it may do so through stimulation of receptors in the chest wall.     

The effect of exposure to high and low frequency hand-arm vibration on finger systolic pressure

Twenty-three patients with hand-arm vibration exposure and diagnosed vibration syndrome were given a thorough clinical and neurophysiological examination, together with finger strain gauge plethysmography. Eleven of the patients were forest workers regularly using chain saws (low frequency vibration exposure), and twelve were metal grinders (higher frequency vibration exposure). Both groups had significantly lower finger blood pressures than healthy controls, and comparisons between the groups indicated that the mean values tended to be lower in the grinders. The findings suggest that hand-arm vibration exposure is associated with obstructive changes in the distal arteries of the fingers, and that vibration frequency is one of the factors determining the severity of the changes and the time of onset of the symptoms.     

Measurement of whole-body vibration by double-pulsed holography

A technique for registering vibration and deformation patterns has been adapted for the measurement of whole-body vibration in humans. Double-exposure holographic interferometry produces three dimensional pictures of the body, allowing exact measurement of the subject's movement between the two pulses. In this study an interval of 600 microseconds between the two pulses was used, producing measurements with a resolution of less than 0.3 X 10(-6)m. The subject standing in a fixed posture, was exposed to the laser beams first without vibration and then with vibration. The picture without vibration is needed as certain movements due to life functions of the body such as heartbeat, blood circulation etc are involved therein. This basic pattern should be considered when analysing the pictures with vibration. Different types of vibration in various postures were studied. Tests were also conducted when a reflective coating was applied to the skin. The results show that the method is applicable for measuring whole-body vibration and suggests further tests with more modern laser equipment which is now available. Such equipment can produce pulses with a high repetition rate and of much better quality than those obtained in this study. Once coordinated to the heartbeat and to the working frequency of the vibrating object, a reliable analysis of whole-body vibration can be maintained.     

Low‐frequency mechanical vibration induces apoptosis of A431 epidermoid carcinoma cells

Cancer research is increasingly focused on discovering strategies to induce cancer cell apoptosis without affecting surrounding normal cells. One potential biocompatible method is mechanical vibration, which has been developed as part of the emerging field of mechanomedicine. Previous studies of mechanical vibration have employed high‐frequency vibration, which damages healthy cells. In this study, we examined the effects of brief (1 h) low‐frequency (20 Hz) mechanical vibration on glucose consumption and survival (apoptosis, necrosis, HMGB1 release) of the human epidermoid carcinoma cell line A431. We found that apoptosis, but not necrosis, was significantly increased at 48 h after mechanical vibration compared with cells maintained in static culture. In keeping with this, extracellular release of HMGB1, a necrosis marker, was lower in cultures of A431 cells subjected to mechanical vibration compared with control cells. Glucose consumption was increased in the first 24 h after mechanical vibration but returned to control levels before the onset of apoptosis. Although the precise intracellular mechanisms by which low‐frequency mechanical vibration triggers apoptosis of A431 cells is unknown, these results suggest a possible role for metabolic pathways. Mechanical vibration may thus represent a novel application of mechanomedicine to cancer therapy.