Significance of spring migration and flexibility in flight-muscle histolysis in waterstriders (Heteroptera, Gerridae)

Abstract. 1. Individuals of long-winged waterstrider (Gerridae) species were found in spring far from their breeding habitats, which indicates that they fly before reproduction.
2. Field samples and laboratory studies show that once they return to their breeding sites, many individuals of three waterstrider species ( Gerris odontogaster (Zett.), Gerris lacustris (L.) and Limnoporus rufoscutellatus (Lat.)) histolyse wing muscles and lose flight ability during their reproductive period.
3. The extent of flight-muscle histolysis varies with environmental factors. Food scarcity affects flight-muscle histolysis in G.odontogaster females. In G.Lacustris , flight-muscle histolysis was more common in the laboratory than in the field samples. Proportionately more females than males lost their flight ability by the end of the reproductive period.
4. Flight ability had direct costs in reproductive potential with (non-flyer) females, which histolysed their flight muscles, laying more eggs than (flyer) females, which maintained flight ability. This was also the case during food scarcity. Non-flyer males of G.odontogaster survived longer than flyer males.
5. Spring migration was distinguished from dispersal during the reproductive period, because these flights serve different functions. Flight-muscle histolysis of females during reproduction is a qualitative reproductive option, with a trade-off between dispersal ability and reproductive potential. Ability to change reproductive behaviour depending on environmental conditions increases an individual's ability to cope with a large variety of habitats.     

Shortening of the period of the circadian rhythm by a K+ channel blocker, tetraethylammonium, in the duckweed Lemna gibba G3

The period of the circadian rhythm of uptake of K+ by Lemna gibba strain G3 (duckweed), cultured in a flow medium, was shortened by continuous application of 0.5 mM tetraethylammonium chloride (TEA), which functions as a K+ channel blocker in both animal and plant cells. Other quaternary ammonium ions shortened the period of the rhythm in direct proportion to their ability to block K+ channels in cells of the nervous system. Ca2+ appears to be specific in its ability to antagonize this action of TEA and of its analogues.     

Genetic control ofHylemya antiqua III. Differences in pupation ability between two strains

Some relevant traits of a wild (L) and a laboratory (C) strain of Hylemya antiqua (Meigen ), determining differences in their pupation ability under experimental conditions have been investigated in relation to genetic control. The wild strain showed an intrinsic higher pupation ability than the laboratory strain. The minimum feeding period was 0.6 days longer for the C strain. The minimum larval dry weight was different for the two strains. With a normal feeding period C larvae pupated on average 1.63 days later than L larvae. By the shortening of the larval feeding period an acceleration of the larval development of both strains was observed: the acceleration of development was more marked for the wild strain. This result has been contrasted with published works on Drosphila. The consequences of these differences as far as the competitive ability of each strain is concerned, have been discussed in relation to genetic control.     

Transformation of Trichothecenes in Ileal Digesta and Faeces from Pigs

The capacity of pig gastrointestinal microflora to metabolise the trichothecenes 3-acetyl-deoxynivalenol (3-acDON) and nivalenol (NIV) was investigated. 3-acDON was deacetylated to DON in anaerobic incubations with pig faeces collected at different pig farms. Furthermore, both 3-acDON and NIV were metabolised to the corresponding de-epoxy metabolite in these incubates. Five pigs, in which the gastrointestinal microflora lacked the ability to transform 3-acDON and NIV to their corresponding de-epoxidated metabolites, were given low levels of DON in the feed for seven weeks. The gastrointestinal micro-organisms did not acquire the de-epoxidation ability during the seven week long exposure period. At the end of the exposure period, faeces from pigs with a known de-epoxidation ability was spread out in the pens and left for 24 hours. One week after the faeces had been spread out in the pens, the de-epoxidation ability was found in faecal incubations from four out of five experimental pigs. This change in metabolic ability of the intestinal de-epoxidation ability was not accompanied by any detectable changes in the DNA-profiles of the bacterial community composition. The results show that the intestinal de-epoxidation ability is common at pig farms in the Uppsala area, and that the ability may be transferred between pigs in a stock.     

Time-dependent loss of prostaglandin E release by adherent cells in response to stimulation by thyroid cells: Prevention of this loss by phytohemagglutinin

Preplating human adherent peripheral blood mononuclear cells (PBMC) for up to 24 hr results in a progressive decrease in their basal PGE release, and in the loss of their ability to increase PGE release during a subsequent 72-hr coculture period with allogeneic human thyroid cells. Phytohemagglutinin (PHA) present during a 24-hr adherent-cell preplating period prevents, in part, the loss of this PGE response to thyroid cells. These data indicate that adherent cells require continual stimulation by the thyroid cells or by PHA in order to maintain their ability to increase PGE secretion in response to thyroid cells.     

Recovery of penetration ability in protease-treated zona-free mouse eggs occurs coincident with recovery of a cell surface 94 kD protein.

Previous studies have demonstrated that protease treatment of zona-free mouse eggs impairs sperm-egg interaction (Boldt et al.: Biol Reprod 39:19-27, 1988) and causes modification of a 94 kD egg plasma membrane protein (Boldt et al., Gamete Res 23:91-101, 1989). In this report, the ability of eggs to recover penetration ability following protease treatment was examined. Zona-free mouse eggs were isolated and treated with either trypsin or chymotrypsin (1 mg/ml, 20 min), then cultured for 0, 3, or 6 hr before insemination. Eggs cultured for 3 or 6 hr displayed significantly higher penetration levels than eggs inseminated immediately after protease treatment, indicating a recovery of penetration ability during the 3 or 6 hr incubation period. The recovery of penetration ability was not blocked by inclusion of cyclohexamide (50 micrograms/ml) during the 3 or 6 hr culture period, indicating that protein synthesis was not required for recovery of fusion ability. Cell surface radiolabeling studies with 125I revealed that a 94 kD cell surface protein was lost immediately following trypsin or chymotrypsin treatment but was found on the egg surface after the 3 or 6 hr recovery period. Recovery of the 94 kD egg surface protein occurred in the presence of cyclohexamide, and metabolic radiolabeling studies with 35S-methionine confirmed that synthesis of a 94 kD protein was blocked by cyclohexamide. These results suggest that the recovery of penetration ability after protease treatment of zona-free eggs is due to recovery of the 94 kD cell surface protein, providing further evidence for the involvement of the 94 kD protein in sperm-egg interaction.     

Strategies for the storage of Ancylostoma caninum third-stage larvae

Although cryopreservation protocols for storage of hookworm larvae have been described, the circumstances under which the technique is necessary to ensure larval survival are not well defined. The motility of infective-stage larvae (as judged by observation) and their ability to migrate through canine skin in vitro were measured over a 7-mo period in worms held at room temperature and worms that had been cryopreserved at the start of the experiment. Cryopreserved worms showed motility and migration proportions of 45.6-48.0% and 26.8- 34.0%, respectively, throughout the experiment, compared with percentages of 92.7 and 84.1%, respectively, in the original fresh worms. Larvae held at room temperature showed a gradual decrease in motility and migration ability over the experimental period. Motility and migratory ability of cryopreserved larvae was only significantly higher (P < 0.01) than room temperature-stored larvae from 4 and 5 mo onward, respectively.     

Metabolism and action of insulin and glucagon in goat during lactating and dry period

The metabolism and action of insulin and glucagon were investigated in goats during mid lactating (50 days postpartum) and during the dry period. The animals were fed hay and concentrate during lactation (1:1) and only hay during dry period. Pulse doses of unlabelled insulin and glucagon were injected intravenously. The disappearance of insulin from the circulation was faster during lactation than during dry period; the metabolic clearance rate of insulin was significantly increased during lactation. In contrast, the kinetic parameters of glucagon disappearance were very similar during the two periods. Basal plasma hormones (i.e. before hormone injection) were higher during lactation than during dry period; the molar ratio insulin:glucagon was left unchanged. The increase in plasma insulin following glucagon-stimulated hyperglycaemia was similar during the two periods. The ability of insulin to elicit a decrease in blood glucose was markedly impaired during lactation when compared to dry period. In contrast the ability of glucagon to increase blood glucose was slightly improved during lactation. Those endocrine changes could be related to the effect of both lactation and diet.     

Plating efficiency measurements and the experimental control of ageing of adult human skin fibroblasts in vitro.

Adult human skin fibroblasts were serially cultured by means of eleven protocols differing in inoculum size, duration of culture between passage and the ability of the medium to support cell division. Each protocol was terminated only when there were too few cells for further subculturing. The fraction of the cells of an inoculum adhering to the growth surface was unaffected by serial subculturing or by differences in protocol. The final cell count at the end of a period of culture and the plating efficiency for the next culture diminished progressively with serial subculturing. Nevertheless, the computed number of cell generations per culture period of those cells which divided was unaffected by serial passaging. The total number of cell doublings accruing during an entire protocol depended only on the duration of the period of culture between successive passages which was characteristic of that protocol. The observations can be accounted for quantitatively by the following assumptions. A cell which loses its ability to divide after a given period of culture nevertheless continues to grow in size during the next period of culture. The increase in volume of cell substance during any such period is the same whether or not a cell divides. The second postulate is that the probability of a cell being able to divide at the start of a period of culture is proportional to the probability that it will not lose this ability by the following period of culture.     

Conditional Mutants of Meiosis in Yeast

Three temperature-sensitive mutants, spo1-1, spo2-1, and spo3-1, were characterized with respect to their behavior in sporulation medium at a restrictive temperature. The time of expression of the functions defective in the mutants was determined by temperature-shift experiments during the sporulation process. In addition, each mutant was examined for the following: (i) its ability to undergo the nuclear divisions of meiosis; (ii) deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis; (iii) protein turnover; and (iv) colony-forming ability after exposure to sporulation medium. Mutant spo1-1 is defective in a function which confers a temperature-sensitive period which extends over 32% of the sporulation cycle. The temperature-sensitive period of mutant spo2-1 occupies 34% of the cycle, whereas the temperature-sensitive period of mutant spo3-1 extends over 2% of the sporulation cycle. Cytological evidence indicates that all three mutants initiate but do not complete the meiotic nuclear divisions. The DNA content of sporulation cultures of mutants spo1-1 and spo3-1 did not increase to the wild-type level; DNA synthesis in spo2-1 was normal. All three strains exhibit a loss of colony-forming ability during incubation in sporulation medium at the restrictive temperature. RNA and protein synthesis and protein turnover occur in the mutants.     

A meta-analysis of the traits affecting dispersal ability in butterflies: can wingspan be used as a proxy?

1. Dispersal ability of a species is a key ecological characteristic, affecting a range of processes from adaptation, community dynamics and genetic structure, to distribution and range size. It is determined by both intrinsic species traits and extrinsic landscape-related properties. 2. Using butterflies as a model system, the following questions were addressed: (i) given similar extrinsic factors, which intrinsic species trait(s) explain dispersal ability? (ii) can one of these traits be used as a proxy for dispersal ability? (iii) the effect of interactions between the traits, and phylogenetic relatedness, on dispersal ability. 3. Four data sets, using different measures of dispersal, were compiled from published literature. The first data set uses mean dispersal distances from capture-mark-recapture studies, and the other three use mobility indices. Data for six traits that can potentially affect dispersal ability were collected: wingspan, larval host plant specificity, adult habitat specificity, mate location strategy, voltinism and flight period duration. Each data set was subjected to both unifactorial, and multifactorial, phylogenetically controlled analyses. 4. Among the factors considered, wingspan was the most important determinant of dispersal ability, although the predictive powers of regression models were low. Voltinism and flight period duration also affect dispersal ability, especially in case of temperate species. Interactions between the factors did not affect dispersal ability, and phylogenetic relatedness was significant in one data set. 5. While using wingspan as the only proxy for dispersal ability maybe problematic, it is usually the only easily accessible species-specific trait for a large number of species. It can thus be a satisfactory proxy when carefully interpreted, especially for analyses involving many species from all across the world.     

广州市农作物系统与大气的CO2交换

在广泛收集资料和实验分析的基础上,研究了广州市各种农作物系统与大气CO2交换.分析了各种农作物系统净生产力吸收CO2的能力和碳汇功能大小.结果表明:2005年广州市8种农作物系统作物净生产力吸收CO2 4 032 366t·a-1,其土壤CO2排放3981753t·a-1,吸收大于排放,对大气CO2而言,整个农作物系统是一个弱的碳汇;水稻、甘蔗、木薯和果用瓜4种连作或高杆作物系统每年作物净生产力吸收CO2量大于土壤CO2的排放量,系统具有较大的碳汇功能,花生、大豆、花卉和蔬菜4种矮杆作物系统每年作物净生产力吸收CO2量小于土壤CO2的排放量,系统起着碳源作用;果实或经济产量生长在地上部分的作物其单位面积吸收CO2能力比果实(块根)生长在地下的作物大;除花生在生育期间生物量吸收CO2量少于同期土壤排放以外,其余7种作物在生育期间生物量吸收CO2的量大于同期土壤排放,大多数农作物在生育期间具有碳汇功能,在撂荒期才体现碳源作用.     

How long will honey bees (<Emphasis Type="Italic">Apis mellifera</Emphasis> L.) be stimulated by scent to revisit past-profitable forage sites?

Honey bees utilise floral food sources that vary temporally in their relative and absolute quality. Via a sophisticated colony organisation, a honey bee colony allocates its foragers such that the colony focuses on the most profitable forage sites while keeping track of changes within its foraging environment. One important mechanism of the allocation of foragers is the ability of experienced foragers to revisit past-profitable forage sites after a period of temporary dearth caused by, for example, inclement weather. The scent of past-profitable forage within the colony brought back by other foragers is sufficient to reactivate these experienced foragers. Here I determine for how long bees react to the scent of a past-profitable forage site. I show that the ability of foragers to revisit the location of a past-profitable food source diminishes rapidly over a period of 10 days, until no forager reacts to the cue (scent). I discuss the implications of these findings with respect to the colony’s ability to react rapidly to changing foraging conditions.     

Impaired flight ability--a cost of reproduction in female blue tits

When prey are attacked by predators, escape ability has an obvious influence on the probability of survival. Laboratory studieshave suggested that flight performance of female birds mightbe affected by egg production. This is the first study of changesin take-off ability, and thus potentially in predation risk,during reproduction in wild birds. We trapped individual maleand female blue tits repeatedly during the breeding season.Females were 14% heavier and flew 20% slower (probably as aconsequence of a lower ratio of flight muscle to body mass)during the egg-laying period than after the eggs had hatched.However, flight muscle size did not change to compensate for changes in body mass over this period. In contrast, males showedno changes in either body mass, muscle size, or flight abilityover the same period. Furthermore, the impairment of flightin females increased with the proportion of the clutch thathad been laid, an effect that was independent of body mass and muscle size. This indicates that egg production causes additional physiological changes in the female body that produce impairedlocomotor performance. We suggest that courtship feeding offemale blue tits by their mates might reduce predation riskduring the period when female take-off ability is impairedby reducing the time females have to spend foraging and thusreducing the time they are exposed to increased predation.     

Prion interference is due to a reduction in strain-specific PrPSc levels

When two prion strains infect a single host, one strain can interfere with the ability of the other to cause disease but it is not known whether prion replication of the second strain is also diminished. To further investigate strain interference, we infected hamsters in the sciatic nerve with the long-incubation-period transmissible mink encephalopathy (TME) agent DY TME prior to superinfection of hamsters with the short-incubation-period HY TME agent. Increases in the interval between TME agent inoculations resulted in an extension of the incubation period of HY TME or a complete block of the ability of the HY TME agent to cause disease. The sciatic nerve route of inoculation gave the two TME strains access to the same population of neurons, allowing for the potential of prion interference in the lumbar spinal cord. The ability of the DY TME agent to extend the incubation period of HY TME corresponds with detection of DY TME PrP(Sc), the abnormal isoform of the prion protein, in the lumbar spinal cord. The increased incubation period of HY TME or the inability of the HY TME agent to cause disease in the coinfected animals corresponds with a reduction in the abundance of HY TME PrP(Sc) in the lumbar spinal cord. When the two strains were not directed to the same populations of neurons within the lumbar spinal cord, interference between HY TME and DY TME did not occur. This suggests that DY TME agent replication interferes with HY TME agent replication when the two strains infect a common population of neurons.     

Synthesis of prostaglandins and cyclic AMP by cultured embryonic palate mesenchyme at various population densities

During embryonic development, facial and palate mesenchymal cells exhibit differential growth rates. Normal palatal growth is regulated in part by hormones and growth factors. Because hormonal responsiveness of some cells correlates with their cell density, we have investigated the relationship between embryonic palate mesenchymal cell population density and their ability to synthesize prostaglandins (PGs) and cyclic AMP. Primary cultures of palate mesenchymal cells exhibited typical lag, log, and stationary phases of growth with a doubling time of 32-34 hrs. The ability of cells to produce PGE2 in response to a calcium ionophore (A23187), an activator of phospholipase A2 (melittin), arachidonic acid, or serum was maximal during the period of early exponential growth. Prostaglandin F2 alpha synthesis in response to A23187 or arachidonic acid showed a similar transient increase also corresponding temporally to the period of early exponential growth. The ability to synthesize PGF2 alpha in response to melittin, however, failed to diminish after early exponential growth. The pattern of cAMP synthesis in response to isoproterenol and PGE1 was different from that seen for induced prostaglandin synthesis. A transient increase in sensitivity to isoproterenol and PGE1 was seen that corresponded temporally to the period of late exponential growth just prior to attainment of confluency. Decreased sensitivity to stimulation of either prostaglandin or cAMP production as the cells became confluent was shown to be a density-dependent phenomenon; confluent cultures that were subcultured to reestablish logarithmic growth exhibited density-dependent hormonal responses identical to those seen in primary cultures. The ability of palate mesenchymal cells to synthesize both prostaglandins and cAMP, thought to be critical for proper palatal development, might thus be related to local differential craniofacial growth rates.     

Adventitious rooting: examining the role of auxin in an easy- and a difficult-to-root plant

Therooting responses of cuttings of difficult-to-root lilac (Syringavulgaris) and easy-to-root forsythia(Forsythia×intermedia)were compared. The rooting ability of lilac cuttings declined over the growingseason (May–June). There was also a decline in the initial concentrationof free IAA at the base of the cuttings, but there was not a tight relationshipbetween basal IAA concentration and rooting ability. Polar auxin transportability was measured in lilac and forsythia during the period of maximum growthby [³H]IAA application to stem internodal tissue. Transport abilitydeclined in lilac over this time period, particularly in terms of transportintensity and percentage of [³H]IAA transported. In contrast thechanges in polar auxin transport ability in forsythia were less marked. Thisdifference between species was maintained in winter hardwood cuttings, withforsythia tissue showing greater polar auxin transport ability than lilac. Theimportance of polar auxin transport for adventitious rooting was demonstratedinboth lilac and forsythia softwood cuttings by use of the polar transportinhibitor 2,3,5-triiodobenzoic acid (TIBA). Overall the results indicate thatdifferences in polar auxin transport ability between lilac and forsythiacontribute to differences in rooting ability.     

Does improved decision-making ability reduce the physiological demands of game-based activities in field sport athletes?

This study investigated the effects of video-based perceptual training on pattern recognition and pattern prediction ability in elite field sport athletes and determined whether enhanced perceptual skills influenced the physiological demands of game-based activities. Sixteen elite women soccer players (mean +/- SD age, 18.3 +/- 2.8 years) were allocated to either a video-based perceptual training group (N = 8) or a control group (N = 8). The video-based perceptual training group watched video footage of international women's soccer matches. Twelve training sessions, each 15 minutes in duration, were conducted during a 4-week period. Players performed assessments of speed (5-, 10-, and 20-m sprint), repeated-sprint ability (6 x 20-m sprints, with active recovery on a 15-second cycle), estimated maximal aerobic power (V O2 max, multistage fitness test), and a game-specific video-based perceptual test of pattern recognition and pattern prediction before and after the 4 weeks of video-based perceptual training. The on-field assessments included time-motion analysis completed on all players during a standardized 45-minute small-sided training game, and assessments of passing, shooting, and dribbling decision-making ability. No significant changes were detected in speed, repeated-sprint ability, or estimated V O2 max during the training period. However, video-based perceptual training improved decision accuracy and reduced the number of recall errors, indicating improved game awareness and decision-making ability. Importantly, the improvements in pattern recognition and prediction ability transferred to on-field improvements in passing, shooting, and dribbling decision-making skills. No differences were detected between groups for the time spent standing, walking, jogging, striding, and sprinting during the small-sided training game. These findings demonstrate that video-based perceptual training can be used effectively to enhance the decision-making ability of field sport athletes; however, it has no effect on the physiological demands of game-based activities.     

三维旋进式振动疗法联合运动想象训练对脑卒中偏瘫患者上肢功能、平衡能力及日常生活活动能力的影响

摘要 目的：研究运动想象训练联合三维旋进式振动疗法对脑卒中偏瘫患者平衡能力、上肢功能及日常生活活动能力的影响。方法：研究对象来源于苏州市立医院康复医学科2019年4月~2022年4月期间收治的80例脑卒中偏瘫患者。入院后按照计算机产生随机数进行随机分配为对照组和研究组,每组各40例。对照组患者接受运动想象训练,研究组患者接受三维旋进式振动疗法联合运动想象训练。对比两组疗效、上肢功能、平衡能力及日常生活活动能力。结果：两组患者干预2周后、干预4周后Fugl-Meyer上肢运动功能量表（FM-uL）、上肢动作研究量表（ARAT）评分均升高,且研究组均高于对照组同期;改良Ashworth痉挛量表（MAS）评分均下降,且研究组低于对照组同期（P<0.05）。两组患者干预2周后、干预4周后Berg平衡量表（BBS）评分均升高,且研究组高于对照组同期（P<0.05）。两组患者干预2周后、干预4周后Barthel指数（BI）评分均升高,且研究组高于对照组同期（P<0.05）。结论：运动想象训练联合三维旋进式振动疗法干预脑卒中偏瘫患者,可有效改善患者的平衡能力、上肢功能及日常生活活动能力。     

Internal artificial vagina (IAV) to assess breeding behavior of young Bos taurus and Bos indicus bulls

Bull breeding soundness evaluation (BBSE) usually neglects the libido and mating ability evaluation. The internal artificial vagina (IAV) permits semen sampling, as well as mating ability evaluation. Few studies have been performed using IAV with young bulls and there are none with Bos indicus bulls. The present study evaluated sexual behavior, mating ability and semen quality in young Bos taurus (Devon) and B. indicus (Nellore) bulls using the IAV device. In the first experiment, 52 Devon bulls, 18-25 months old were observed, and the behavior and mating ability recorded over a 10-min period within a restrained mount-cow with an IAV inserted. In the second experiment, 20 Nellore bulls, 20-30 months old were evaluated over a 20 min period. Of the 52 Devon bulls, 45 (86.5%) had semen recovered with the IAV, 31 (69.0%) were considered satisfactory. Nellore bulls exhibited a different sexual behavior, with 10 bulls not showing any interest in the females. Four bulls demonstrated sexual interest only once, e.g., sniffing, two showed interest on more than one occasion, and four had more than two mounts or mounting attempts. None out of the Nellore bulls was collected with IAV. The IAV was an effective and welfare-promoting animal technology for the evaluation of semen quality and mating ability of B. taurus bulls. However, the IAV was not adequate for young Nellore bulls, probably due to their quiescent sexual behavior and delayed sexual maturity. Further studies are needed to evaluate the performance of the IAV for older Nellore bulls.