General function and endocrine control of the posterior lymph hearts in Bufo marinus and Rana catesbeiana

The effects of hypervolemia and graded increases in arginine vasotocin (AVT), angiotensin II (ANGII), and atrial natriuretic peptide (ANP) on lymph heart pressure (P(lh)) and rate (f(lh)) were examined in Bufo marinus and Rana catesbeiana. The P(lh) and f(lh) for normally hydrated B. marinus at rest were 1.45+/-0.01 kPa and 52.8+/-0.38 beats min(-1). The P(lh) and f(lh) were significantly lower in R. catesbeiana, 1.05+/-0.01 kPa and 48.4+/-0.35 beats min(-1). Hypervolemia, induced by intravenous infusion of isotonic saline, stopped the lymph hearts at volumes of 0.48%+/-0.06% and 0.32%+/-0.04% body mass in B. marinus and R. catesbeiana, respectively, equivalent to an 8% increase of their respective plasma volumes. ANP had no effect on P(lh) or f(lh) at any of the dosages tested. ANGII decreased f(lh) in both species, approximating the physiological range of concentrations. AVT, at physiological concentrations, increased P(lh) 48% in B. marinus and 38% in R. catesbeiana without changing f(lh) in either species. At higher than physiological dosages, P(lh) and f(lh) in both species declined. The results suggest that AVT, normally released during hemorrhage and dehydration, would increase lymph heart output and help compensate for the hypovolemia. This is a contrary result to previous work using supraphysiologic doses of AVT.     

The effects of erythrocythemia on blood viscosity,maximal systemic oxygen transport capacity and maximal rates of oxygen consumption in an amphibian

Graded erythrocythemia was induced by isovolemic loading of packed red blood cells in the toad, Bufo marinus. Blood viscosity, hematocrit, hemoglobin concentration, maximal aortic blood flow rate and maximal rates of oxygen consumption were determined after each load. Blood viscosity was related to hematocrit in the expected exponential manner; ln eta = 0.43 + 0.035 Hct. Maximal blood flow rates in the dorsal aorta were inversely proportional to blood viscosity and fit predictions of the Poiseuille-Hagen flow formula. The effect of increased blood viscosity was to reduce aortic pulse volume, but not maximal heart rate. Maximal systemic oxygen transport capacity (aortic blood flow rate X hemoglobin concentration X O2 binding capacity of hemoglobin) was linearly correlated with the maximal rate of oxygen consumption. These date indicate that optimal hematocrit theory is applicable for maximal blood flow rates in vivo, and that systemic oxygen transport is the primary limitation to aerial VO2 max in amphibians.     

Pyruvate transport in isolated cardiac mitochondria from two species of amphibian exhibiting dissimilar aerobic scope: Bufo marinus and Rana catesbeiana

Cardiac mitochondria were isolated from Bufo marinus and Rana catesbeiana, two species of amphibian whose cardiovascular systems are adapted to either predominantly aerobic or glycolytic modes of locomotion. Mitochondrial oxidative capacity was compared using VO2 max and respiratory control ratios in the presence of a variety of substrates including pyruvate, lactate, oxaloacetate, beta-hydroxybutyrate, and octanoyl-carnitine. B. marinus cardiac mitochondria exhibited VO2 max values twice that of R. catesbeiana cardiac mitochondria when oxidizing carbohydrate substrates. Pyruvate transport was measured via a radiolabeled-tracer assay in isolated B. marinus and R. catesbeiana cardiac mitochondria. Time-course experiments described both alpha-cyano-4-hydroxycinnamate-sensitive (MCT-like) and phenylsuccinate-sensitive pyruvate uptake mechanisms in both species. Pyruvate uptake by the MCT-like transporter was enhanced in the presence of a pH gradient, whereas the phenylsuccinate-sensitive transporter was inhibited. Notably, anuran cardiac mitochondria exhibited activities of lactate dehydrogenase and pyruvate carboxylase. The presence of both transporters on the inner mitochondrial membrane affords the net uptake of monocarboxylates including pyruvate, beta-hydroxybutyrate, and lactate; the latter potentially indicating the presence of a lactate/pyruvate shuttle allowing oxidation of extramitochondrial NADH. Intramitochondrial lactate dehydrogenase and pyruvate carboxylase enables lactate to be oxidized to pyruvate or converted to anaplerotic oxaloacetate. Kinetics of the MCT-like transporter differed significantly between the two species, suggesting differences in aerobic scope may be in part attributable to differences in mitochondrial carbohydrate utilization.     

土壤干旱对水稻叶片光合速率和碳酸酐酶活性的影响

以适应性广的水稻品种“汕优 6 3”为材料 ,具有较高的光合速率但适应性较差的品系“NAU30 3”为对照 ,比较了不同阶段的叶片光合机构对于干旱处理的适应性。结果表明“汕优 6 3”具有较广泛的适应性 ,在逆境条件下仍能维持较高的光合速率 ,这可能和叶片中碳酸酐酶活性对逆境的响应程度高有关。这种对干旱逆境的适应性反应只在叶片光合功能的可逆衰退阶段发生     

Functional roles for the compartmentalization of the subcutaneous lymphatic sacs in anuran amphibians

Compliance of the subcutaneous lymph sacs of the hindlimbs increases from distal to proximal, as does limb segment mass (and presumably rate of lymph formation), for the semiaquatic bullfrog Rana catesbeiana and the cane toad Bufo marinus but not the aquatic clawed toad Xenopus laevis. Subcutaneous lymph-sac compliances vary interspecifically. The distal-to-proximal increase in lymph-sac compliance and estimates of lymph formation rate in the various hindlimb segments indicate that partitioning of hindlimb subcutaneous lymphatic sacs establishes a differential decrease in the intra-lymph-sac pressure for R. catesbeiana and B. marinus. These pressure differentials constitute a "compliance pump" that drives distal-to-proximal intersac lymph flow. The compliance pump alone explains lymphatic return for the aquatic frog X. laevis but does not explain how lymph would reach the dorsally located lymph hearts for terrestrial anurans, so we hypothesize that skeletal muscle pumps return lymph from the femoral and pubic lymph sacs to the lymph heart. This is a fundamentally different role of the subcutaneous lymph-sac system than has been previously proposed. We suggest that the more proximal subcutaneous lymph sacs are important for fluid storage because they have a relatively high compliance.     

野葛毛状根离体培养与异黄酮生产

用发根农杆菌（Agrobacterium rhizogenes）R1601菌株感染野葛（Pueraria lobata(Willd.)Ohwi）叶片外植体后获得的毛状根,经连续4次继代培养,鲜重增加到最初的6.2倍。PH为5.5的1/2SH液体培养基较适合野葛毛状根的生长。与自然根相比,毛状根在无激素的1/2SH液体培养基中离体培养20d后,鲜重增加22.6倍,释放入培养液中的异黄酮量增加10.6倍。毛状根生产异黄酮的量略高于自然根,且根中含量明显高于愈伤组织及茎中异黄酮的含量。培养液体积影响毛状根的离体生长及异黄酮的释放。     

Ontogeny of maternal behavior and brood pheromone in crayfish

Summary Third stage crayfish were maze tested to determine their preference for paired stimulus solutions of females in various breeding stages and of males. Formerly unattractive female crayfish begin to produce a brooding attractant when they deposit eggs (Fig. 1). The attractant become maximally effective when the eggs hatch (Fig. 2). Behavioral changes occur as larvae develop into the fourth stage and result in both a reduced larval attraction to any mother's stimulus (Figs. 3, 4) and a tendency to become solitary. At the same time the mother's attractant becomes less potent (Fig. 5). The mother receives feedback from her developing brood which maintains her behavior and attractive stimulus (Fig. 8). In the absence of this feedback, the mother's behavior changes to include larval predation in some species (Fig. 4, 6, 7) and her stimulus is no longer attractive (Figs. 8, 9).I gratefully acknowledge the help received from my graduate committee: Drs. Albert Carlson, Ronald R. Hoy, Emil W. Menzel and Charles Walcott. I also thank Mr. Kenneth Lantz of the District 6 Office of the Louisiana Department of Fisheries and Wildlife for providing laboratory space and assistance during my study in Louisiana. Funded by U.S. National Science Foundation Grant G.U. 3850.     

NaCl胁迫对海蓬子(Salicornia bigelovii Torr.)离子区室化、光合作用和生长的影响

用含有0、100、300、600mmol/L的NaCl的Hoagland培养液处理海蓬子幼苗,处理一定时间后测定其鲜重、干重、离子含量、Na /K 比值、Na 在细胞中的分布、光合速率、叶绿体超微结构等的变化.结果表明一定浓度NaCl处理促进了海蓬子的生长,300mmol/L左右的NaCl是海蓬子生长的最适盐度.盐处理条件下海蓬子主要将Na 、Cl-积累在地上部,且主要储存在液泡中.随盐处理浓度的增加海蓬子地上部的Na /K 比增大;光合速率在低盐度下随盐浓度的升高而增大,高盐度下受到抑制;叶绿体超微结构在高盐度下受到部分破坏.     

KCl和NaCl处理对盐生植物碱蓬幼苗生长和水分代谢的影响

研究了用不同浓度KCl和等浓度NaCl处理的盐生植物碱蓬幼苗水分代谢的变化.结果表明,NaCl处理显著促进碱蓬生长,根吸水增加,含水量高于对照.而相同浓度KCl处理却严重抑制碱蓬生长,含水量显著下降,400 mmol/L的 KCl处理后6 d,地上部分发生萎蔫,尔后死亡.KCl处理伤害碱蓬的原因之一是抑制根系吸水,而对蒸腾速率无显著影响,即水分吸收速率与蒸腾速率比值下降,植株缺水引起伤害.     

梨树花芽休眠解除与活性氧代谢的关系

梨树(Pyrus bretschneideri Rehd.)自然休眠和休眠解除时,花芽的活性氧代谢发生变化.O2-·产生速率和H2O2的含量在休眠期间上升,在休眠后期下降.抗氧化系统中SOD活性在自然休眠期呈下降趋势,自然休眠结束活性上升.POD和CAT活性在自然休眠期上升.抗氧化物质AsA和GSH的含量随休眠进行而下降,休眠解除过程中重新升高.APX和GR的活性在休眠期间活性下降,休眠结束活性迅速上升.这些结果表明:花芽的休眠与活性氧的代谢有很大关系.     

渗透调节对低温伤害敏感大豆种子质膜氧化还原活性的影响

选用对吸胀冷害敏感的大豆[Glycine max(L.)Merr.]品种"黑河23"种子为试材,研究了渗透调节增强大豆种子活力过程中种子质膜氧化还原活性的变化.结果表明,大豆种子活力指数与种子质膜氧化还原活性呈正相关.与对照相比,渗控12 h显著提高大豆种子活力,表现在发芽指数、活力指数和TF生成量的提高,种子质膜NADH和NADPH氧化速率及Fe(CN)63-和EDTA-Fe3 还原速率明显上升;随着引发时间的延长,种子活力上升变缓,种子质膜NADH和NADPH氧化速率及Fe(CN)63-还原速率上升速度变慢,EDTA-Fe3 的还原速率在渗控24 h后开始下降,但渗控72 h仍高于对照.     

水稻胚乳细胞质膜内陷的超微结构和磷酸酶的细胞化学定位

对生长分化期水稻胚乳细胞的质膜内陷进行了超微结构和磷酸酶的细胞化学研究。结果表明 ,胚乳细胞内的小泡、内质网常与胞间连丝相连 ;质膜形态多变 ,功能活跃 ,由局部起伏的波纹状发展成明显内陷 ,深浅不一 ,多呈袋状 ,袋中包含着大小不一的泡状物 ;有些内陷脱离质膜成为胞质中的囊泡 ,表现出活跃的内吞现象。除细胞间隙中含有圆球状的内含物外 ,在质膜内陷和囊泡中常含有大量的内含物。H ATP酶定位结果显示 ,质膜及其邻近的泡状物周围有酶的分布 ;而酸性磷酸酶定位在液泡、胞间隙和其中的泡状内含物周围 ;在质膜及其内陷形成的囊泡中有G6P酶的分布。这些结果表明胞间隙和质膜内陷在物质的运输中可能起着重要作用     

The role of retinula cell types in fixation behaviour of walkingDrosophila melanogaster

Summary Fixation behaviour of free walking wild typeDrosophila and various retinal mutants was tested in a circular arena. Optomotor response was also measured as a test of the function of R1-6.ora andsev,ora do not fixate a narrow stripe (10° or 20°, Fig. 1) but are able to orient towards broad stripes (110° or 180°, Fig. 1). The behaviour ofsev is not different from wild type. Fixation behaviour ofw rdgB is similar toora (Figs. 5, 6). The mutantora has a maximum optomotor response at low contrast frequencies (Fig. 2), but the threshold for this response is at least one log unit higher than in wild type orsev (Fig. 8). The light intensity threshold at 550 nm of fixation to a broad stripe (110°) is 1–2 log units higher inora than in wildtype, and 4 log units higher insev,ora and the structural brain mutantVam (Fig. 7).The conclusions are that retinula cells R1-6 mediate fixation to a narrow stripe at high and low ambient light intensities, and to a broad stripe at low ambient light levels. R8, possibly in conjunction with R1-6, contributes to orientation towards broad stripes at high light intensities. This hypothesis is supported by evidence that blue-adapted white-eyed flies are able to orient towards a broad stripe at high blue light intensities (Figs. 9 and 12). Blue adaptation totally eliminates the optomotor response (Figs. 10, 11) and so the optomotor response observed inora at low contrast frequencies (Figs. 2 and 8) is most likely due to the small remnants of the rhabdomeres of R1-6 that remain.Abbreviations PDA prolonged depolarising afterpotential - ERG electroretinogram     

‘Absolute steepness’ of ramps as an essential cue for auditory pattern recognition by a grasshopper (Orthoptera; Acrididae; Chorthippus biguttulus L.)

Male grasshoppers of the species Chorthippus biguttulus react to female songs with a characteristic turn towards the female. The probability of turning towards female song models was used to evaluate those parameters which are essential for a signal to be interpreted as female song.

1. The shape of sound pulses turned out to be most decisive; pulses with ramps rising gradually over 3 and more ms were efficient (Figs. 2, 3), whereas rectangularly modulated pulses evoked only weak responses and only when pulse intervals were between 3 and 5 ms (Fig. 2). The decline of a pulse did not influence its efficiency (Fig. 3). In particular, pulses with sudden onsets and gradual declines were as weakly effective as rectangularly modulated ones and thus remarkably less effective than pulses with ramp-like onsets (Fig. 4).
2. Intensity tuning curves suggest, that the absolute steepness of ramps (expressed as μbar/ms) is detected by the grasshopper nervous system (Figs. 6, 7), possibly by processing the delay in excitation onset of at least two receptor types differing in threshold sensitivity.
3. The sawtooth shape of pulses in female signals is suggested to be adaptive with respect to directional hearing.

     

Resource partitioning of sonar frequency bands in rhinolophoid bats

Summary In the Constant Frequency portions of the orientation calls of various Rhinolophus and Hipposideros species, the frequency with the strongest amplitude was studied comparatively. (1) In the five European species of the genus Rhinolophus call frequencies are either species-specific (R. ferrumequinum, R. blasii and R. euryale) or they overlap (R. hipposideros and R. mehelyi). The call frequency distributions are approximately 5–9 kHz wide, thus their ranges spead less than ±5% from the mean (Fig. 1). Frequency distributions are considerably narrower within smaller geographic areas. (2) As in other bat groups, call frequencies of the Rhinolophoidea are negatively correlated with body size (Fig. 3). Regression lines for the genera Rhinolophus and Rhinolophus, species from dryer climates have on the average higher call frequencies than species from tropical rain forests. (4) The Krau Game Reserve, a still largely intact rain forest area in Malaysia, harbours at least 12 syntopic Rhinolophus and Hipposiderso species. Their call frequencies lie between 40 and 200 kHz (Fig. 2). Distribution over the available frequency range is significantly more even than could be expected from chance alone. Two different null hypotheses to test for random character distribution were derived from frequency-size-relations and by sampling species assemblages from a species pool (Monte Carlo method); both were rejected. In particular, call frequencies lying close together are avoided (Figs. 4, 5). Conversely, the distribution of size ratios complied with a corresponding null hypothesis. This even distribution may be a consequence of resource partitioning with respect to prey type. Alternatively, the importance of these calls as social signals (e.g. recognition of conspecifics) might have necessitated a communication channel partitioning.     

水稻抽穗后剑叶衰老过程中光合关键酶的基因表达

协优 930 8、培矮 6 4s/ 9311和汕优 6 3三个超级高产水稻品种抽穗后 ,剑叶中光合速率减小、叶绿素含量下降、SOD活力降低和MDA含量上升的幅度不同 ,显示它们开花结实过程中叶片衰老的速度不同 ,以汕优 6 3衰老最快 ,协优 930 8最慢 ,培矮 6 4s/ 9311居中。Northern杂交和免疫定量研究表明 ,汕优 6 3和培矮6 4s/ 9311剑叶rbcS(Rubisco小亚基基因 )和rca(Ru bisco活化酶基因 )mRNA的表达随抽穗后天数的增加而下降 ,而协优 930 8在抽穗后第 10天才开始下降 ;Rubisco和Rubisco活化酶蛋白含量的下降趋势与rbcS和rcamRNA的变化趋势相似。因此 ,水稻抽穗后剑叶衰老过程中光合能力的下降与光合关键酶基因(rbcS和rca)表达下降密切相关     

Learning and discrimination of coloured papers in the walking blowfly,Lucilia cuprina

Summary A new training and testing paradigm for walking sheep blowflies, Lucilia cuprina, is described. A fly is trained by presenting it with a droplet of sugar solution on a patch of coloured paper. After having consumed the sugar droplet, the fly starts a systematic search. While searching, it is confronted with an array of colour marks consisting of four colours displayed on the test cardboard (Fig. 1). Colours used for training and test include blue, green, yellow, orange, red, white and black.Before training, naive flies are tested for their spontaneous colour preferences on the test array. Yellow is visited most frequently, green least frequently (Table 2). Spontaneous colour preferences do not simply depend on subjective brightness (Table 1).The flies trained to one of the colours prefer this colour significantly (Figs. 5 and 9–11). This behaviour reflects true learning rather than sensitisation (Figs. 6–7). The blue and yellow marks are learned easily and discriminated well (Figs. 5, 9, 11). White is also discriminated well, although the response frequencies are lower than to blue and yellow (Fig. 11). Green is discriminated from blue but weakly from yellow and orange (Figs. 5, 9, 10). Red is a stimulus as weak as black (Figs. 8, 9). These features of colour discrimination reflect the spectral loci of colours in the colour triangle (Fig. 14).The coloured papers seem to be discriminated mainly by the hue of colours (Fig. 12), but brightness may also be used to discriminate colour stimuli (Fig. 13).     

转ipt和反义ACO基因番茄的叶片衰老相关特性

以ipt和反义ACO转化的两类转基因番茄纯系为材料,研究在植株不同生长发育阶段,不同叶位中,与叶片衰老相关的生理生化指标.结果表明:两类基因导入番茄后,均可增强内源iPA和IAA表达水平,增加或保持番茄叶片的叶绿素含量、提高光合效率,进而明显地延缓植株的叶片衰老,提高单株果实产量.但它们调控叶片衰老的途径不同,ipt主要通过提高CTK的水平延缓叶片衰老,而反义ACO则主要是通过抑制乙烯生成,间接提高IAA的水平来实现.     

An in vitro physiological preparation of a vertebrate communicatory behavior: chirping in the weakly electric fish, Apteronotus

1. An in vitro preparation of the medullary pacemaker nucleus of the weakly electric fish Apteronotus leptorhynchus was studied which fires regularly and synchronously at the fish's characteristic frequency of electric organ discharge (EOD). Upon bipolar stimulation of tissue regions through which pass prepacemaker nucleus afferents to the pacemaker, a brief, transient increase in discharge frequency ensued at short-latency (Fig. 1A). 2. Intracellular recordings revealed that the acceleration was accompanied by a depolarization and decline in action potential amplitude. The magnitude of these changes was both phase- (Fig. 5) and amplitude-dependent, with the latter showing an evident threshold effect (Figs. 4 and 12). The response was reversibly blocked by high Mg2+ saline (Fig. 1B), and the magnitude of the accelerations showed marked facilitation during repeated stimulation (Fig. 6). 3. Optical and histological identification allowed characteristically different responses in the intracellular recordings to be attributed to the two cell types of the pacemaker nucleus: pacemaker and relay cells (Figs. 2 and 3). Similar responses have been observed at these respective recording locations in the intact animal during chirping (Dye and Heiligenberg 1987). 4. Simultaneous recordings of pairs of cells revealed a transient change in the phase relationship of firing during the accelerations which was most marked between relay and pacemaker cells (Fig. 7). These dual recordings also revealed that the relay cells depolarize and accelerate more than pacemaker cells (Fig. 10), suggesting that they are the principal effectors of this behavioral modulation. 5. Trains of pulses additionally elicited a long-lasting frequency elevation which occurred at a slightly higher threshold than the brief accelerations. This slow frequency change relaxed back to baseline following a biexponential time course which closely resembled that of a distinct behavior seen in intact fish, termed 'yodeling' (Dye 1987).