Ph?nologie und Brutbiologie des Kiebitzes (Vanellus vanellus): 17j?hrige Beobachtungen in Nordwestdeutschland

Zusammenfassung In einer agrarisch strukturierten Kulturlandschaft in und um Osnabrück wurden in 17 Jahren (1976–1992) Phänologie und Brutbiologie einer überwiegend auf Ackerland brütenden Kiebitzpopulation untersucht. In der Regel kehrten die ersten Kiebitze von Mitte Februar bis Anfang März ( = 26.2.) aus ihren Winterquartieren zurück. Durchschnittlich begannen sie am 28. 3. mit der Eiablage (frühstens 11. 3. 1990). Gelege waren gewöhnlich von Anfang April bis Mitte Juni vorhanden (letztes Gelege 25. 6. 1991). Die ersten Küken schlüpften in den letzten April- oder ersten Maitagen ( = 27.4.; Extremwert 10. 4. 1990). Von den Nachgelegen schlüpften regelmäßig bis Mitte Juni ( = 19.6.) die letzten Küken (letzter Schlupftermin 25. 6. 1991). Als Folge vieler Nachgelege wurden jungeführende Altvögel über einen sehr langen Zeitraum von Ende April bis Mitte Juli beobachtet (spätester Termin 23. 7. 1988). Alljährlich begann im Mittel am 5. 6. der Frühsommerwegzug. Zwischen dem Beginn der Eiablage und den Monatsmitteltemperaturen sowie zwischen der Eiablage und den Frosttagen der jeweiligen Monate Februar und März bestand ein Zusammenhang. Die mittlere Gelegegröße in 386 Nestern betrug 3,83 Eier. Kiebitze bebrüteten 24 bis 28 Tage (durchschnittlich 26 Tage) ihre Gelege. Aus 221 Nestern mit 841 Eiern schlüpften 788 Küken, was einer Schlupfrate von 93,7% oder 3,59 Küken pro erfolgreichem Gelege entsprach. Aus sämtlichen 438 Gelegen (einschließlich der zerstörten) schlüpften im Mittel 2,49 Küken.

---

Phenology and breeding biology of Lapwing (Vanellus vanellus): Results of a 17 years' study in NW-Germany

Summary Phenology and breeding biology of Lapwing on arable land near the city of Osnabrück (Lower Saxony) were studied. A set of nearly complete data concerning the seasonal rhythm in a period of 17 years (1976–1992) was gathered. Arrival used to be from the middle of February till begin of March ( = 26.2.). Egg-laying begann on an average on 28. 3., the earliest egg-laying was observed on 11. 3. (1990), last clutch was seen on 25. 6. (1991). Clutch-presence extended from early April till middle of June. Hatching took place from late April to first of May ( = 27.4.; earliest date: 10. 4. 1990). Hatching of replacement clutches was observed till mid of June ( = 19.6.). Last hatching day was 25. 6. 1991. Adults with chicks occurred from end of April till mid of July, latest date was the 23. 7. (1988). Early summer migration started in average on 5. 6. The annual variation of the start of laying by Lapwing was related to mean monthly temperature and to the number of frost days in February and March. Average clutch size of 386 clutches was 3.83 eggs. Incubation took 24 to 28 days (average 26 days). From 221 clutches with 841 eggs 788 chicks hatched, from which was calculated a hatching rate of 93.7% or 3.59 chicks per successful clutch. From 438 clutches (including the destroyed ones), in average 2.49 chicks hatched.

     

Linkage analysis using multiple DNA polymorphic markers in normal families and in families with fragile X syndrome

Summary Linkage data, using the polymorphic markers 52A (DXS51), F9, 4D-8(DXS98), and St14(DXS52), are presented from 14 fragile X pedigrees and from 7 normal pedigrees derived from the collection of the Centre d'Étude du Polymorphisme Humaine. A multipoint linkage analysis indicates that the most probable order of these four loci in normal families is DXS51-F9-DXS98-DXS52. Recombination frequencies ( ) corresponding to maximum LOD scores ( ) were obtained by two-point linkage analysis for a nuber of linkage groups, including: DXS51-F9 ( =5.94, =0.03), F9-DXS98 ( =0.51, =0.26), F9-DXS52 ( =0.84, =0.27), and DXS98-DXS52 ( =0.32, =0.20). A multipoint linkage analysis of these loci, including the fragile X locus, was also performed for the fragile X population and the data support the relative order (DSX51, F9, DXS98)-FRAXA-DXS52. Recombination frequencies and maximum LOD scores, which again were derived from two-point linkage analyses, were obtained for the linkage groups DXS51-F9 ( =9.96, =0) and F9-DXS52 ( =0.07, =0.45), as well as for the groups DXS51-FRAXA ( =2.42, =0.15), F9-FRAXA ( =1.30, =0.18), DXS98-FRAXA ( =0.05 =0.36), and DXS52-FRAXA ( =2.42 =0.15). The linkage data was further tested for the presence of genetic heterogeneity both within and between the fragile X and normal families for the intervals DXS51-F9, F9-DXS52, F9-FRAXA, and DXS52-FRAXA using a modification of the A test. Except for the interval F9-FRAXA (P<0.10) there was no evidence of genetic heterogeneity for each of the various linkage groups examined. The heterogeneity detected for the interval F9-FRAXA, however, was most likely due to one family (Fx-28) that displayed very tight linkage between these two loci.     

Dynamics of cardiorespiratory function in Standardbred horses during different intensities of constant-load exercise

Summary Six Standardbred horses were used to evaluate the time course of pulmonary gas exchange, ventilation, heart rate (HR) and acid base balance during different intensities of constant-load treadmill exercise. Horses were exercised at approximately 50%, 75% and 100% maximum oxygen uptake ( max) for 5 min and measurements taken every 30 s throughout exercise. At all work rates, the minute ventilation, respiratory frequency and tidal volume reached steady state values by 60 s of exercise. At 100% max, the oxygen consumption ( ) increased to mean values of approximately 130 ml/kg·min, which represents a 40-fold increase above resting . At the low and moderate work rates, showed no significant change from 30 s to 300 s of exercise. At the high work rate, the mean at 30 s was 80% of the value at 300 s. The HR showed no significant change over time at the moderate work rate but differing responses at the low and high work rates. At the low work rate, the mean HR decreased from 188 beats/min at 30 s to 172 beats/min at 300 s exercise, whereas at the high work rate the mean HR increased from 204 beats/min at 30 s to 221 beats/min at 300 s exercise. No changes in acid base status occurred during exercise at the low work rate. At the moderate work rate, a mild metabolic acidosis occurred which was nonprogressive with time, whereas the high work rate resulted in a progressive metabolic acidosis with a base deficit of 16 mmol/l by 300 s exercise. It is concluded that the kinetics of gas exchange during exercise are more rapid in the horse than in man, despite the relatively greater change in in the horse when going from rest to high intensity exercise.Symbols and abbreviations E minute ventilation - V _T tidal volume - oxygen uptake - carbon dioxide output - oxygen pulse - ventilatory equivalent for oxygen - ventilatory equivalent for carbon dioxide - R respiratory exchange ratio - HR heart rate - SBC standard bicarbonate - STPD standard temperature and pressure dry - BTPS body temperature and pressure saturated - arterial oxygen content - arteriovenous oxygen content difference - Rf respiratory frequency     

Seasonal changes in the activation of crossbridge motions of isolated thick filament from Limulus striated muscle

Summary In dynamic light scattering, measurements of the intensity-intensity time correlation function from a suspension of rod-like particles of length L could reveal dynamical information related to translational and internal motions of those particles. For a suspension of thick filaments isolated from the myosin-regulated, striated muscles of Limulus at KL>1 (where K is the scattering vector), the average characteristic linewidth ( ) increased with the addition of Ca²⁺ or with the depletion of ATP. The increase in the with the addition of Ca²⁺ could be due to the presence of energy-requiring, high-frequency motions of the crossbridges activated by Ca²⁺. The increase in which occurred with the depletion of ATP was assumed to be mainly due to the thermal motions of the crossbridges after they had moved radially away from the filament backbone. The percentage increase in following the addition of Ca²⁺ was found to be seasonal, i.e., values of obtained from thick filaments isolated between the middle of June and the middle of September were smaller than those obtained during the rest of the year. The effect of temperature on the percentage increase in was also different. The increase showed a maximum at about 35°C during the summer and at about 25°C at other times. However, the percentage increase in developed under ATP-depleted conditions showed no temperature-related maximum. The number of bound Ca²⁺ per myosin molecule was 1 during the summer and 2 at other times.Abbreviations DLS dynamic light scattering - L length - K scattering vector - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - average characteristic line width Deceased     

Relationship between cardiac output and oxygen uptake at the onset of exercise

The purpose of the present study was to assess the relationship between the rapidity of increased gas exchange (i.e. oxygen uptake ) and increased cardiac output ( ) during the transient phase following the onset of exercise. Five healthy male subjects performed multiple rest-exercise or light exercise (25 W)-exercise transitions on an electrically braked ergometer at exercise intensities of 50, 75, or 100 W for 6 min, respectively. Each transition was performed at least eight times for each load in random order. The was obtained by a breath-by-breath method, and was measured by an impedance method during normal breathing, using an ensemble average. On transitions from rest to exercise, rapidly increased during phase I with time constants of 6.8–7.3 s. The also showed a similar rapid increment with time constants of 6.0–6.8 s with an apparent increase in stroke volume (SV). In this phase I, increased to about 29.7%–34.1% of the steady-state value and increased to about 58.3%–87.0%. Thereafter, some 20 s after the onset of exercise a mono-exponential increase to steady-state occurred both in and with time constants of 26.7–32.3 and 23.7–34.4 s, respectively. The insignificant difference between and time constants in phase I and the abrupt increase in both and SV at the onset of exercise from rest provided further evidence for a cardiodynamic contribution to following the onset of exercise from rest.     

Respiration of the emersed shore crab at variable ambient oxygenation

Summary In the intertidal shore crab,Carcinus maenas, pH and values of the prebranchial venous hemolymph, and , the PO₂ values of the arterialized cardiac hemolymph, , were measured, and the ventilatory activity was assessed by measuring the hydrostatic pressures at the exits of the epibranchial cavities, under four environmental conditions: normoxic water, normoxic air, hypoxic gas, hyperoxic gas.In the crab breathing normoxic air, was lower and higher than in animals breathing normoxic water. With the switch to hypoxic gas, ventilation increased and and decreased. With the switch to hyperoxic gas, ventilation decreased, and increased and decreased.Thus these crabs breathing air were not as well oxygenated as when breathing air-equilibrated water, and because of their low , they were relatively hypervetilating and hypocapnic compared to air-breathing vertebrates. Hyperoxic breathing, increasing and reducing ventilatory drive, led to increased . Conversely, was reduced by hypoxic breathing. These observations suggest that the gas exchanger of intertidal crabs is not as successfully designed for air breathing as that of land-colonizing insects and air-breathing vertebrates.     

Respiratory responses of elite oarsmen, former oarsmen, and highly trained non-rowers during rowing, cycling and running

The position of the body and use of the respiratory muscles in the act of rowing may limit ventilation and thereby reduce maximal aerobic power relative to that achieved in cycling or running, in spite of the greater muscle mass involved in rowing. This hypothesis was investigated for three groups of male subjects: nine elite senior oarsmen, eight former senior oarsmen and eight highly trained athletes unskilled in rowing. The subjects performed graded exercise to maximal effort on a rowing ergometer, cycle ergometer and treadmill while respiratory minute volume and oxygen consumption were monitored continuously. The VE at a given during intense submaximal exercise (greater than 75% of maximal ) was not significantly lower in rowing compared with that in cycling and treadmill running for any group, which would suggest that submaximal rowing does not restrict ventilation. At maximal effort, and for rowing were less than those for the other types of exercise in all the groups, although the differences were not statistically significant in the elite oarsmen. These data are consistent with a ventilatory limitation to maximal performance in rowing that may have been partly overcome by training in the elite oarsmen. Alternatively, a lower maximal VE in rowing might have been an effect rather than a cause of a lower maximal if maximal was limited by the lower rate of muscle activation in rowing.     

Effects of root temperature on uptake of nitrate and ammonium ions by barley grown in flowing-solution culture

Summary Barley plants (Hordeum vulgare L.) grown from seed for 28 days in flowing solution culture were subjected to different root temperatures (3, 5, 7, 9, 11, 13, 17, 25°C) for 14 days with a common air temperature of 25/15°C (day/night). Uptake of NH₄ and NO₃ ions was monitored separately and continuously from solutions maintained at 10 M NH₄NO₃ and pH 6.0. Effects of root temperature on unit absorption rate , flux and inflow were compared. After 5 days , and increased with temperature over the range 3–11°C for NH₄ ions and over the range 3–13°C for NO₃ ions, with little change for either ion above these temperatures. Q₁₀ temperature coefficients for NH₄ ions (3–13°C) were 1.9, 1.7 and 1.6 for , and respectively, the corresponding values for NO₃ ions being 5.0, 4.5 and 4.6. For both ions, , and changed with time as did their temperature dependence over the range 3–25°C, suggesting that rates of ontogenetic development and the extent of adaptation to temperature may have varied among treatments.     

Reciprocal inhibition of human motoneurons with different firing frequencies

A study was made of the effect of reciprocal inhibition on individual firing motoneurons in the extensor carpi ulnaris and soleus muscle in human subjects. Peristimulus histograms (PSH) were plotted at different average frequency of motoneuron firing ( ) and the change in duration of interspike intervals (ISI) was analyzed. For reciprocal inhibition, as for other types of inhibition, is a factor in the effectiveness of motoneuron inhibition. The duration of inhibition apparent in the PSH, the sizes of zones of inhibition effectiveness in the ISIs and lengthening of the intervals are dependent on . For all motoneurons, the low range is most favorable for effective inhibition. The dependence of effectiveness of a volley on the time of its arrival within the ISI is also analyzed.Institute for Problems of Information Transmission, Russian Academy of Sciences, Moscow. Translated from Neirofiziologiya, Vol. 24, No. 6, pp. 643–653, November–December, 1992.     

Selenium deficiency in yugoslavia

Data on selenium (Se) deficiency in Yugoslavia are presented. The results include Se content of soil, cereal crops, and garlic grown in these soils, and human serum and scalp hair from several towns and regions. All data indicate a serious Se deficiency: soil (n=140), the mean value of 200±69.6 μg/kg Se; wheat, (58) = 20.5 ± 12.4 μg/kg; corn, (79) = 13.7 ± 13.6 μg/kg; and garlic, (66) = 13.7 ± 17.1 μg/kg Se. Analyses of human tissue show a very low Se status of the Yugoslav population: serum, (n=875) = 50.0 ± 18.0 μg/L and scalp hair, (388) = 94 ± 16 μg/kg Se. In some regions, Se contents of grain, garlic, and human serum and hair are approaching those in the low-Se belt in China. It is assumed that very low Se status of a human population could be a risk factor in the development of Balkan Endemic Nephropathy (BEN) and in a high incidence of urinary tract tumors (UTT) in endemic areas. A portion of these results were presented at the International Symposium on Selenium, Belgrade, May 12–15, 1991, Abstracts p.1, Serbian Academy of Sciences and Arts.     

Estimation of surface charges in some biological membranes

Summary The resting membrane potential data existing in the literature for the giant axon of the squid, frog muscle and barnacle muscle have been analyzed from the standpoint of the theory of membrane potential due to Kobatake and co-workers. The average values derived for the effective charge density (where is a constant, , and represents the fraction of counterions that are free, and is the stoichiometric charge density in the membrane) present on the different biomembranes existing in their normal ionic environment are 0.3, 0.325 and 0.17 M for the squid axon, frog and barnacle muscles, respectively. On the assumption that the values of are 0.4 and 0.2 for nerve and muscle membranes, respectively, values of 0.75, 1.62 and 0.85 M have been derived for the stoichiometric charge density present in the respective biological membranes. These correspond to 1 negative charge per 222, 103 and 195 Å of the membrane area of the squid axon, frog and barnacle muscles, respectively.     

The nucleotide sequence ofBeneckea harveyi 5S rRNA

Summary The complete sequence of the 5S rRNA from the bioluminescent bacterium,Beneckea harveyi has been determined to be p U G C U U G G C G C C A U A G C G A U U-G G A C C C A C U G A (U) C U U C A U U C C-G A A C C A G A A G U G A A C G A A U U A-G G C C G A U G G U G U G U G G G G C U-C C C C A U G U A G A G U A G G A A U C G-C C A G G U (U)_OH.Two sites of sensitivity to ribonuclease T₂ cleavage were identified; at A₄₁ and either A₅₄ or A₅₅. Comparison with existing sequence information fromEscherichia coli andPhotobacterium phosphoreum clarifies the amount of diversity among the bioluminescent bacteria and provides further insight into their phylogenetic position. Sequence heterogeneities were encountered and the importance of these in interpreting 5S rRNA data is discussed.     

Times to exhaustion at 100% of velocity at [(V)\dot]\textO\text2 \dot V{\text{O}}_{\text{2}} max and modelling of the time-limit / velocity relationship in elite long-distance runners

The aim of this study was to measure running times to exhaustion (Tlim) on a treadmill at 100% of the minimum velocity which elicits _{max max} in 38 elite male long - distance runners _max = 71.4 ± 5.5 ml.kg^–1.min^–1 and _max = 21.8 ± 1.2 km.h^–1). The lactate threshold (LT) was defined as a starting point of accelerated lactate accumulation around 4 mM and was expressed in _max. Tlim value was negatively correlated with _max (r = -0.362, p< 0.05) and _max (r = –0.347, p< 0.05) but positively with LT (%v _max) (r = 0.378, p < 0.05). These data demonstrate that running time to exhaustion at _max in a homogeneous group of elite male long-distance runners was inversely related to _max and experimentally illustrates the model of Monod and Scherrer regarding the time limit-velocity relationship adapted from local exercise for running by Hughson et al. (1984) .     

Temperature induced peripheral blood flow changes in lizards

Summary The influence of local temperature changes within the posterior portion of the body on dorsal aorta blood flow ( ), femoral arterial pressure (P _a ), peripheral resistance (R), skin blood flow ( ) and skeletal muscle blood flow ( ) was examined in unanesthetized lizards (Iguana iguana andTubinambis nigropunctatus). In response to local heating of the hind legs and tail and increased,P _a was generally unchanged,R decreased and decreased or was unchanged (Fig. 2). It is suggested that the acquisition of heat may be favored by diverting the increase in away from the muscle to the warmer skin. In response to cooling and decreased,P _a was generally unchanged, R increased and increased or was unchanged. Hence, during cooling the retention of heat may be favored by diverting blood away from the skin to the deeper muscle. The muscle-skin shunt is under sympathetic control since following blockade with phenoxybenzamine HCL (Dibenzyline) muscle blood flow changes in response to temperature were qualitatively similar to those of skin (Fig. 4). These changes in peripheral circulatory patterns are independent of changes in heart rate or deep body temperature.Baker and Weathers were predoctoral and postdoctoral trainees, respectively, under USPHS Grant HE-05696. This study was also supported by NSF Grant GB-8523 and Los Angeles County Heart Association Grant 437IG.     

ESR-Untersuchungen zur Radikalstruktur in bestrahltem L-Leucinhydrochlorid

Zusammenfassung Bei Röntgenbestrahlung von L-Leucin·HCl bei Zimmertemperatur wird das >C-H-Proton unter Bildung des Radikals (CH₃)₂ C-CH₂-CHNH₃ ⁺-COOH abgetrennt. Das von acht -Protonen stammende ESR-Spektrum wurde wegen nur schwacher Anisotropie der -Protonen-Hfs auch im polykristallinen Zustand vollständig aufgelöst, und es wurden folgende isotrope Aufspaltungen ermittelt: bei Messung bei Zimmertemperatur = 23.5±1 Gauß für sechs äquivalente CH₃-Protonen und =8,0±1 Gauß und = 38,8±1 Gauß für die zwei Methylenprotonen, bei Messung bei 77 °K entsprechend = 22,6±1 Gauß =8,8±1 Gauß und =45,2±1 Gauß (Temperaturabhängigkeit der CH₂-Protonenkopplung). Das bei Zimmertemperatur beobachtete Radikal wird bereits durch Bestrahlung bei 77 °K gebildet.

---

ESR-studies on the structure of radicals in X-irradiated L-leucine hydrochloride

Summary The structure of radicals in X-irradiated polycrystalline L-leucine·HCl has been studied by ESR. At room temperature the radical (CH₃)₂ > C-CH₂-CHNH ₃ ⁺ -COOH is formed by abstraction of the >C-H-proton. The isotropic part of hyperfine interaction with eight -protons has been measured even in polycrystalline state with following values: at 300 °K =23,5±1 gauss for six equivalent CH₃-protons and =8.0±1 gauss and =38.8±1 gauss for two CH₂-protons, at 77 °K =22.6±1 gauss, =8.8±1 gauss and =45-2±1 gauss respectively (the coupling of the CH₂-protons is dependent from temperature). This radical is present already following irradiation at 77 °K.

---

---

Herrn Prof. Dr. habil. Kh.Lohs möchten wir an dieser Stelle für die Unterstützung dieser Arbeit und wertvolle Diskussionen danken. Herrn Ing. N.Klimes, Frl. G.Klein und Herrn J.Benkert gilt unser Dank für die technische Assistenz, Herrn Ing. M.Kresse für die Bestrahlung der verwendeten Proben.     

Are oxygen uptake kinetics at the onset of exercise speeded up by local metabolic status in active muscles?

To assess the rate-limiting factor of oxygen uptake ( ) kinetics at the onset of exercise, six healthy male sedentary subjects performed repeated one-legged constant-load cycle exercise. The one-legged constant-load exercise test consisted of two 5-min periods of pedalling at an exercise intensity of 50 W, with a 5-min rest between periods (these exercise periods, i.e. first and second exercises, were performed by the same leg). The exercise was then repeated using the other leg. In addition, two-legged incremental exercise was investigated to establish whether kinetics were affected by slower heart rate kinetics. The incremental exercise test consisted of two-legged pedalling first with the cycle unloaded as a warm-up for 5 min followed by 50-W exercise for 5 min. The exercise intensity was then increased to 100 W for 5 min. During exercise, gas exchange parameters were determined by the breath-by-breath method and cardiac output ( ) was determined continuously by an impedance technique with a computer-based automated system. To determine the kinetics of heart rate (HR), and , a best fit procedure was employed using least-squares criteria with a time delay, except during the initial increase. During the one-legged constant-load exercise test, kinetics were significantly accelerated by repeated exercise using the same leg. On the other hand, when the exercise was changed to the other leg, kinetics were significantly slower, although kinetics continued to be faster. During the incremental exercise test, although the HR response was slower at the transition from 50-W to 100-W exercise than at the transition from warm-up to 50-W exercise, there were no significant changes in kinetics. These findings suggest that kinetics may be affected by metabolic conditions in the muscle, but not by blood flow ( and/or HR) kinetics.     

Evidence for linkage of the gene causing familial Mediterranean fever to chromosome 17q in non-Ashkenazi Jewish families: second locus or type I error?

Familial Mediterranean fever (FMF) is an autosomal recessive disorder of unknown pathogenesis, characterized by recurrent, selflimited attacks of fever with synovitis, peritonitis, or pleurisy. Using DNAs from affected Israeli families, we have recently mapped the gene causing FMF (designated MEF) to the short arm of chromosome 16, with two-point lod scores in excess of 20. In this report we consider the possibility of a second FMF susceptibility locus. Before discovering linkage to markers on chromosome 16, we had found suggestive evidence for linkage to chromosome 17q, with the following maximal two-point lod scores: D17S74 (pCMM86), = 2.47, ( = 0.20); D17S40 (pLEW101), = 2.15( = 0.15); D17S35 (CRI-pP3-1), = 1.78 ( = 0.15); D17S46 (pLEW108), = 1.69 ( = 0.18), D17S254, = 2.30 ( = 0.20). Moreover, multipoint linkage analysis using D17S74 and D17S40 as fixed loci gave = 3.27 approximately 10 centimorgans (cM) telomeric to D17S40. Data with the chromosome 17 markers alone in our families suggested locus heterogeneity. Nevertheless, our families were not separable into complementary subsets showing linkage either to chromosome 16 or to chromosome 17. We also examined the possibility that the positive lod scores for chromosome 17 might reflect a secondary, modifying locus. By several measures of disease severity, families with positive lod scores for chromosome 17 loci had no worse disease than those with negative lod scores for these loci. We conclude that chromosome 17 does not encode a major FMF susceptibility gene for some of the families, nor does it encode a disease-modifying gene. Rather, it would appear that linkage to chromosome 17 is a false positive (type I) error. These results reemphasize the fact that a lod score of 3.0 corresponds to a posterior probability of linkage of 95%, with an attendant 1 in 20 chance of observing a false positive.     

Polymorphisme électrophorétique des protéines et enzymes sériques et érythrocytaires chez le chimpanzé (Pan troglodytes)

Summary The electrophoretic mobilities of serum enzymes and other proteins were investigated at 35 loci in 25 unrelated individuals of the chimpanzee Pan troglodytes. In this population the mean average of individual polymorphism is =0181, and the average level of heterozygoty =0.022. The same pattern of individual variability is found in Pan troglodytes and Homo sapiens.     

The generation of the proton electrochemical potential and its role in energy transduction

Summary The evidence that all energy transducing membranes can generate a proton electrochemical potential difference, _H, across the membrane and that this potential can be used to transfer energy among energy transducing units and to generate ATP, has increased the interest for the view that _H plays an obligatory role in energy transduction and ATP synthesis. In the present article we shall concentrate on two experimental questions related with the generation and role of _H: (a) the charge/site ratio; (b) the relation between the proton electrochemical potential on one side and the cation electrochemical potential, the phosphate potential and the redox potential on the other. We shall then discuss the view that energy transduction corresponds to a molecular energy machine rather than to a fuel cell.     

Cardiovascular responses to sustained maximal isometric contractions of the finger flexors

This study investigated cardiovascular responses to 2 min sustained submaximal (20% MVC) and maximal (100% MVC) voluntary isometric contractions of the finger flexors in healthy young women. Cardiovascular variables investigated were: heart rate (f _c), mean arterial pressure ( _a), and stroke volume (SV). Doppler echocardiography was used to estimate SV from measures of aortic diameter (AD) and time-velocity integrals. Preliminary studies indicated that AD did not change significantly after 2 min sustained 100% MVC. Therefore, pre-exercise AD values were used to calculate SV before, during and after exercise. During the 2-min 100% MVC period, f _c and _aincreased significantly during the first 30 s of contraction. f _c then remained constant during the remainder of the 2-min contraction period, while _acontinued to rise. SV did not change significantly during the 100% MVC task but increased significantly during recovery from sustained 100% MVC. The data suggest that the magnitude of cardiovascular responses to isometric exercise is dependent on the specific task performed, and that there is a different pattern of response for f _c, _a, and SV during 20% and 100% MVC tasks. Unlike f _c and _a, SV did not change significantly during isometric exercise, but increased significantly after sustained 100% MVC.