Genetic variations in the pre-feeding and pre-oviposition periods among four pure lines in the brown planthopper, <Emphasis Type="Italic">Nilaparvata lugens</Emphasis> (Hemiptera: Auchenorrhyncha:Delphacidae)

In the brown planthopper, Nilaparvata lugens Stål, traits related to ovarian development were compared among four pure lines predominantly expressing the designated characteristics: blackish short-winged (BS), yellowish brown short-winged (YS), blackish long-winged (BL), and yellowish brown long-winged (YL). The pre-oviposition period was longer in the following order: BS < YS < BL = YL line. The pre-feeding period, namely, the time of non-feeding after adult emergence, which was estimated from dry weight loss during starvation, was also longer in the same order: BS < YS < BL = YL. Vitellogenin, the precursor of yolk protein, first appeared in the hemolymph about 1½ days later after the initiation of feeding in respective lines. One-day’s starvation did not have any effect on the timing of vitellogenin’s appearance in the long-winged lines (BL, YL), but delayed it by 1 day in the short-winged lines (BS, YS). Further, we showed that the synthesis of vitellogenin mRNA was induced in the adults even before feeding by being topically applied with juvenile hormone III (JH III). These results suggest that feeding first triggers the increase of JH III titer, which activates vitellogenin synthesis, and enhances ovarian development. Thus, genetic differences in the pre-feeding periods cause the differences in the timings of physiological events relating to ovarian development among the four lines.     

灰飞虱长、短翅型品系对高、低温的适应能力差异

【目的】灰飞虱Laodelphax striatellus种群存在长翅和短翅个体,其翅型分化受遗传和环境条件的影响。本研究旨在明确经连续定向选育的灰飞虱长、短翅型品系对高、低温的适应能力差异。【方法】在室内分别长期定向筛选63和65代建立灰飞虱长、短翅型品系,并在南京田间采集灰飞虱自然种群;分别在25℃, 30℃和35℃恒温条件下测定上述灰飞虱长、短翅型品系和自然种群的繁殖力、存活率和发育历期,测定若虫在5℃和-20℃下的存活率以及若虫和成虫的过冷却点,通过品系间存活率、发育历期、生殖力和过冷却点的比较分析,确定灰飞虱长、短翅型品系对高温和低温的耐受能力。【结果】在25℃, 30℃和35℃下,灰飞虱自然种群雌成虫的繁殖力均显著高于室内筛选后的长、短翅型品系,而长、短翅型品系雌成虫之间的繁殖力均无显著差异;长、短翅型品系的繁殖力在25℃和30℃之间均无显著差异,但自然种群在25℃下的繁殖力显著高于30℃条件下的繁殖力;35℃下长、短翅型品系基本无若虫产生。25℃下长翅型品系、短翅型品系和自然种群若虫的存活率无显著差异,但在30℃下,短翅型品系若虫的存活率显著低于自然种群,而与长翅型品系差异不显著;35℃下长、短翅型品系的若虫最长只能存活到3龄,且两品系间无显著差异,而自然种群可存活到5龄。25℃下,短翅型品系若虫的发育历期显著短于自然种群,而与长翅型品系无差异;但是在30℃下,短翅型品系若虫历期显著长于长翅型品系和自然种群。长翅型品系、短翅型品系和自然种群灰飞虱3-4龄若虫在5℃低温下的存活天数无显著差异,并且长翅和短翅型品系在-20℃极端低温下暴露10 min后其死亡率也无显著差异且均显著高于自然种群。3个品系(种群)成虫的过冷却点无显著差异,但5龄若虫的过冷却点表现为短翅型品系显著高于自然种群,而与长翅型品系无显著差异。【结论】经连续定向选育的灰飞虱长、短翅型品系对低温和高温的适应力基本相当,且低于自然种群。在高温条件下灰飞虱短翅型品系的发育速率低于长翅型品系。     

Diversities in morphological characteristics and seed germination behavior in fruits ofSalsola komarovii Iljin

Two different types of dispersal units (called fruits in this study) were observed inSalsola komarovii Iljin. One is a fruit which has dark brown lignified tepals with long wings and a green seed and falls easily from the mother plant (long-winged type). Another has light brown lignified tepals with short wings and a yellow seed and attaches tightly to the mother plant (short-winged type). This difference of fruit type appeared independently from maturity of fruit. Seeds in the short-winged fruits were in dormancy for a longer period of time than those in the long-winged fruits. The germination rate was significantly higher in the seeds of long-winged fruits. The dormancy in seeds of the long-winged fruits was effectively terminated by reducing the temperature but the effect of chilling was very weak in seeds of the short-winged fruits. It was concluded from these observations that there exists a dimorphism in the fruits of, or a heterocarpy in,S. komarovii. The plants grown under water stress produced mostly short-winged fruits and those grown under well-watered conditions bore fruits of both types. Exogenously applied abscisic acid (ABA) tended to produce the short-winged fruits, suggesting that the heterocarpy was, at least partly, regulated by ABA.     

Expression of three neuropeptide genes (SfEH,SfETH, and SfCCAP) in response to insecticide stress on the white-backed planthopper Sogatella furcifera (Hemiptera: Delphacidae)

Insect neuropeptides are involved in many important developmental processes. Here, we cloned three neuropeptide genes (SfEH, SfETH, and SfCCAP) from Sogatella furcifera (Horváth) and analyzed the relative expression levels of these genes through Real-time Quantitative polymerase chain reaction (RT-qPCR) during different developmental stages and in different wing types of S. furcifera following exposure to sublethal concentrations (LC₁₀ and LC₂₅) of methylaminoavermectin benzoate. The results revealed that the three neuropeptide genes (SfEH, SfETH, and SfCCAP) of S. furcifera contained open reading frame sequences of 222, 636, and 408 bp, encoding 73, 211, and 135 amino acids, respectively. Moreover, the expression of SfEH and SfETH reached its peak on day 3 of the 5^th instar nymph stage, while the SfCCAP expressed pinnacle on 40 min after eclosion. Furthermore, the relative expression levels of the three genes were in the following order: SfEH, short-winged female > long-winged female > long-winged male; SfETH, long-winged female > short-winged female > long-winged male; and SfCCAP, short-winged female > long-winged male > short-winged female. Upon calculating the relative expression of the three peptide genes after 24 and 48 h of treatment with sublethal concentrations of methylaminoavermectin benzoate, it was found that the relative mRNA expression levels of SfEH and SfETH declined upon LC₁₀ treatment but increased upon LC₂₅ treatment. Meanwhile, the relative mRNA expression level of SfCCAP declined upon both LC₁₀ and LC₂₅ treatments. This result will help us understand the effects of pesticides on insect growth and development at the molecular level.     

Relative contribution of genetic and environmental factors to determination of wing morphs of the brown planthopper Nilaparvata lugens

Wing dimorphism is a fascinating feature of the ability of insects to adapt to environments. The brown planthopper (BPH) Nilaparvata lugens, a serious pest of rice, can switch between the long- and short-winged morphs. It has been known that environmental factors can affect the wing morph of BPH. However, it is still unclear whether the effect of environment is dependent on BPH genetic backgrounds or not. In the present study, we established the pure-bred lineages of short- and long-winged BPHs via multigenerational selection, and we found that survival and fecundity were similar between these 2 lineages. Wing morphs of the pure-bred lineages were almost fully dependent on genetics, but independent of the environmental factors, nymphal density and rice plant stage, 2 key factors affecting BPH wing morphs. In the unselected BPH population, short- and long-winged morphs were produced depending on those 2 environmental factors, indicating the contribution of environment to wing morph. In the wing-selected lineages, 4 developmental regulated genes of wing, NlInR1, NlInR2, NlAkt, and NlFoxo were expressed stably in the short-winged adults, but almost silenced in the long-winged adults. However, all these genes were expressed normally with a similar level in both the short- and long-winged adults in an unselected population except NlFoxo. The pure-bred lineages of long- and short-winged morphs exhibited different expression patterns of wing development-regulated genes, suggesting the genetic determination of wing morphs. Effects of environmental factors on wing morphs occurred only in the genetic mix population.     

褐飞虱成虫体内磁性物质检测

地磁定向是昆虫远距离迁飞定向的重要机制之一.本研究以褐飞虱Nilaparvata lugens长翅型和短翅型成虫为研究对象,利用MPMS-7型号超导量子干涉磁强计(磁场范围为±4.8 mA/m,温度范围为1.9 ～ 400 K)检测虫体内的磁性物质,明确其体内的分布状况.结果表明:褐飞虱长翅型雄成虫整个虫体的温度退磁曲...     

Diet of the south polar skua <Emphasis Type="Italic">Catharacta maccormicki</Emphasis> and the brown skua <Emphasis Type="Italic">C. antarctica lonnbergi</Emphasis> at Cierva Point,Antarctic Peninsula

South polar skuas, SPS, (Catharacta maccormicki) and brown skuas, BS, (C. antarctica lonnbergi) are regarded as opportunistic predators. When breeding in sympatry, BS feed mainly on penguin eggs and chicks, while SPS forage almost exclusively at sea. The objective of this study was to determine the diet composition of adult SPS and BS breeding in sympatry, in order to assess food resource partitioning between these species. The total number of food items consumed was 375 for BS and 682 for SPS in 1992–93, and 427 for BS and 579 for SPS in 1995–96. The pellets composition was significantly correlated between skua species for the same breeding season (r _s = 0.67, p = 0.0062 and r _s = 0.81, p < 0.001, for 1992–93 and 1995–96, respectively), and between breeding seasons for the same skua species (r _s = 0.71, p = 0.001 and r _s = 0.81, p < 0.001, for SPS and BS, respectively). Trophic niche breadth of BS was wider than that of SPS (B _A(BS) = 0.28 and B _A(SPS) = 0.24; Z = 7.67; p < 0.001). The trophic niche overlap between BS and SPS was over 65% in both breeding seasons. In agreement with other studies on the diet of these skua species in situations of sympatry, SPS consumed more fish and BS consumed more birds.     

丽斗蟋翅二型雌虫飞行肌和卵巢发育间的资源分配差异

丽斗蟋Velarifictorus ornatus具有明显的翅二型现象, 长翅型与短翅型雌虫的卵巢和飞行肌存在着生理权衡。本研究分别应用蒽酮比色法、 硫代磷酸香草醛法、 考马斯亮蓝染液对羽化后10 d内两型雌虫飞行肌与卵巢内糖原、 总脂及蛋白质含量进行了定量分析。结果表明： 成虫羽化后10 d内, 两型雌虫体重无明显差异(P>0.05), 但短翅型雌虫怀卵量明显多于长翅型雌虫, 而人工脱翅能够促进长翅型雌虫怀卵量增加(P<0.05)。短翅型雌虫飞行肌内蛋白质、 糖原及总脂含量在成虫羽化后10 d内无明显变化, 但长翅型雌虫飞行肌内蛋白质在成虫羽化后3 d时达到最大值564.4±87.5 μg/♀, 糖原与总脂含量分别于羽化后第5天达到最大值85.2±21.7 μg/♀和5 284.7±1 267.4 μg/♀。然后开始下降, 各实验处理天数内, 长翅型雌虫飞行肌内蛋白质、 糖原及总脂含量都显著多于短翅型雌虫(P<0.05)。相反, 各处理天数内, 短翅型雌虫卵巢内蛋白质、 糖原及总脂含量则明显多于长翅型雌虫(P<0.05), 同时虫龄对蛋白质、 糖原及总脂在两型雌虫飞行肌与卵巢内分配也产生明显影响(P<0.05)。人工脱翅能够促进长翅型雌虫卵巢内蛋白质、 糖原及总脂含量增加, 同时诱导飞行肌内蛋白质、 糖原及总脂含量降低, 其中总脂含量在脱翅后10 d时降为2 394.9±1 461.8 μg/♀, 只有最大值的一半, 而与短翅型雌虫相似(P>0.05), 表明总脂为丽斗蟋飞行的主要能源物质。外用保幼激素Ⅲ能够促进长翅型雌虫卵巢内蛋白质、 糖原及总脂含量增加(P<0.05), 但对飞行肌内三者含量无明显影响(P>0.05), 外用早熟素Ⅰ对短翅型雌虫卵巢内蛋白质、 糖原及总脂含量亦无明显影响(P>0.05)。上述结果表明, 丽斗蟋长翅型雌虫首先将获得的资源用于发育飞行所需的飞行肌, 短翅型雌虫则首先将所获得的资源用于发育繁殖所需的卵巢, 但长翅型雌虫飞行肌与卵巢间的资源分配方式受保幼激素的影响。     

Developmental control of ultrasound sensitivity by a juvenile hormone analog in crickets (Teleogryllus oceanicus)

Cricket ears are sensitive to ultrasound as well as to lower, cricket-like sound frequencies. Ultrasound stimuli evoke negative phonotaxis in flying crickets, a behavior that has been interpreted as a defensive response against predation by echolocating bats. A recent study on a wing-dimorphic species, Gryllus texensis, showed that short-winged individuals, which are incapable of flight, are less sensitive to ultrasound, but not to lower sound frequencies, than their long-winged counterparts. The developmental decision to develop as a long- or short-winged individual is made during the last two larval instars, and there is some evidence suggesting that juvenile hormone (JH) has an instructive role, such that high levels of JH result in short-winged individuals. We show that treatment of last-instar larvae of a monomorphic long-winged species, Teleogryllus oceanicus, with a JH analog causes a decrease in sensitivity to ultrasound, but not to the lower sound frequency used for intraspecific communication.     

Seasonal wing length dimorphism in a tropical seed bug: ecological significance of the short-winged form

Summary Short-winged forms of the bug, Jadera aeola, were discovered during the late dry season at a study site on Barro Colorado Island, Panama. They were smaller than long-winged adults not only in elytron and hindwing sizes but also in head, thorax, rostrum and hind femur dimentions. When newly emerged adults were kept under natural photothermal conditions, short-winged females started ovipositing earlier, produced more eggs, and died earlier than did long-winged females. This was partly due to the fact that long-winged adults usually enter diapause after adult energence (Tanaka et al. 1987b). Egg size was another factor contributing to the high egg production in the short-winged form; it was significantly smaller in the short-winged form than that in the long-winged form. Wing form was apparently environmentally induced because all off-spring of short-winged adults became long-winged. No short-winged form was obtained in the laboratory when nymphs were reared on different species of seeds at different photoperiods. Although the factor(s) responsible for determination of the wing form remains unknown, the ecological significance of this short-winged form seems clear, i.e. exploitation of the food resource left in the late dry season. Wing length dimorphism in J. aeola could be a response to unpredictable availability of the food resource determined by seed production of the host plants (Sapindaceae) and by the timing of the onset of a wet season.     

Cryptic female choice predicated on wing dimorphism in decorated crickets

Male decorated crickets, Gryttodes sigllatus, normally lackbind wings and are incapable of flight (short-winged males),but occasionally exhibit fully developed hind wings that makerudimentary flight possible (long-winged males). Long-wingedmales bear a cost of flight in the form of decreased inseminationsuccess, which arises as a consequence of two interrelated factors:(1) long-winged males exhibit a lower reproductive investmentrelative to short-winged males, as measured by the mass of amale's spermatophore and reproductive organs and (2) the postcopulatorybehavior of females favors males that maximize their reproductiveinvestment. Of particular importance to male mating successis the spermatophylax, a large gelatinous mass forming partof the spermatophore and consumed by the female after mating.Consumption of the spermatophylax keeps the female preoccupiedwhile sperm are discharged from the remaining portion of thespermatophore (sperm ampulla) into her repro ductive tract.The spermatophylax of long-winged males is significantly smallerthan that of short-winged males and consequently requires lesstime to consume. As a result, the sperm ampulla of long-wingedmales is frequently removed before its complete evacuation andsignificantly sooner than that of short-winged males. Becausethe spermatophore-removal behavior of females mediates the relativeinsemination success of short-winged and long-winged males,it can be considered a form of cryptic female choice     

Impact of maternal heat stress at insemination on the subsequent reproductive performance of Holstein, Brown Swiss,and their crosses

Heat stress in hot environments is one of the major factors that can negatively affect milk production, reproduction, and the health of dairy cows. The aim of this study was to evaluate the impact of maternal heat stress at insemination on the subsequent reproductive performance of the pure Holstein (HO), Brown Swiss (BS), and their F₁ crossbred (BF) cows, under subtropical Egyptian conditions. The influence of temperature–humidity index (THI) on the pregnancy rate, fetal loss rate, calving traits, and reproductive indices were investigated. Fetal loss rate of pure HO was significantly increased from 17.1% at low THI to 24.9% at greater THI (odds ratio = 2.09; P = 0.032). Furthermore, abortion and stillbirth rates of pure HO were significantly increased from 3.6% and 3.8%, respectively, at low THI to 7.2% and 5.9%, respectively, at greater THI (odds ratio = 2.17 and 2.58; P = 0.037 and 0.031, respectively). In contrast, BS and BF cows can tolerate the heat stress, as there were no differences in the fetal loss, abortion, and calving difficulty rates at the different levels of THI. Pure HO cows had a significant longer calving interval and days open at high THI (449 and 173 days, respectively), compared with low THI (421 and 146 days, respectively). On the contrary, BS and BF cows had no difference in the calving interval at the different levels of THI. Our results indicate that pure BS and BF cows have a better adaptability and competent reproductive performance than pure HO under subtropical conditions.     

Diversity in seed germination behavior in relation to heterocarpy inSalsola komarovii Iljin

Seed germination behavior in two types of dimorphic fruits inSalsola komarovii Iljin (Chenopodiaceae) was studied. The germination percentage was much higher in the long-winged type than in the short-winged type when the fruits were tested for germinability. If lignified perianths were removed from the fruits, seeds of both types germinated at higher percentages and the difference in the germination percentage between two types decreased. The extract of the perianths inhibited the seed germination. Abscisic acid was detected in the extract of the perianths by enzyme-linked immunosorbent assay and its level was higher in the short-winged type than in the long-winged type. Germinability in both types was lost one year after harvest when the fruits were stored at room temperature and the germination was tested with fruits. When the seeds were tested, however, the short-winged type germinated even two years after the harvest; the germinability of the short-winged type lasted one year longer than that of the long-winged type. Light irradiation was not required for the seed germination in either type regardless of presence or absence of the perianths. No clear difference between the two types was observed either in optimal temperature for the germination or in strength of the resistance to salinity.     

A new species of <Emphasis Type="Italic">Rhinogobius</Emphasis> (Teleostei: Gobiidae) from the Julongjiang Basin in Fujian Province,China

Ten specimens of a new freshwater goby, Rhinogobius longyanensis were collected from the small tributary of the Julongjiang Basin, Fujian Province, southeastern China. The new species can be distinguished from all congeneric species by following unique combination of features: second dorsal fin rays I, 8; anal fin rays I, 7–8; pectoral fin rays modally 17; longitudinal scale series 30–32; predorsal scales 6–8; vertebral count 10 + 17 = 27; three parallel, deep brown oblique stripes crossing on cheek; branchiostegal membrane with 24–28 orange red spots in male; body with 5–6 deep brown blotches; pectoral fin base with a blackish brown bar. A diagnostic key to all nominal species with high vertebral counts from mainland Southeast Asia, China, Taiwan, and Japan is also provided.     

Reliability of an incremental exercise test to evaluate acute blood lactate,heart rate and body temperature responses in Labrador retrievers

Thirteen healthy Labrador retrievers underwent a 5-stage incremental treadmill exercise test to assess its reliability. Blood lactate (BL), heart rate (HR), and body temperature (BT) were measured at rest, after each stage of exercise, and after a 20-min recovery. Reproducibility was assessed by repeating the test after 7 days. Two-way MANOVAs revealed significant differences between consecutive stages, and between values at rest and after recovery. There was also a significant reduction in physiological strain between the first and second trial (learning effect). Test reliability expressed as typical error (BL = 0.22 mmol/l, HR = 9.81 bpm, BT = 0.22°C), coefficient of variation (BL = 19.3%, HR = 7.9% and BT = 0.6%) and test–retest correlation (BL = 0.89, HR = 0.96, BT = 0.95) was good. Results support test reproducibility although the learning effect needs to be controlled when investigating the exercise-related problems commonly observed in this breed.     

The role of macropters during range expansion of a wing-dimorphic insect species

Marked changes in distribution in consequence of global warming have been observed not only for highly mobile insect taxa, which are capable of flight, but also for wing-dimorphic species with predominantly short-winged individuals. In the special case of wing-dimorphic species, it is likely that the rarer long-winged (macropterous) morph plays an important role in the dispersal process, but little is known about how and to what extent it is involved. The aim of our study was to provide more information on the mechanisms behind dispersal processes in wing-dimorphic insects at expanding range margins. As solitary individuals are believed to play an important role in the range expansion of wing-dimorphic species (potential dispersers), we recorded the number of long-winged and short-winged solitary males at the local range margin of our model organism Metrioptera roeselii (Orthoptera: Tettigoniidae) in NW Germany. To investigate differences in dispersal capability (% macropters) between populations with different colonisation histories, we studied 43 populations of M. roeselii. Our results show that about 2/3 of the solitary males were long-winged and these long-winged individuals were significantly more frequent in recently colonised areas. Moreover, M. roeselii had a significantly higher dispersal capability (% macropters) in high-density populations and in recently established populations at the expanding range margin compared to populations characterised by medium- or long-term establishment nearer to the range core. Our study is the first that quantifies the importance of macropters for the recent range expansion of a wing-dimorphic species and it provides for the first time detailed insights into the complex dispersal processes that take place at the expanding range margin. It is likely that density stress and a changed genetic predisposition to become macropterous, and thus a combination of both ecological and evolutionary effects, leads to a high percentage of macropters in recently colonised areas.     

A new species of <Emphasis Type="Italic">Rhinogobius</Emphasis> (Teleostei: Gobiidae) from the Feiyunjiang Basin in Zhejiang Province,China

A new freshwater goby, Rhinogobius wuyanlingensis, was collected from Wuyanling National Natural Conservation Area, Taishun, Zhejiang Province, China. The species can be distinguished from all congeneric species by the following unique combination of features: second dorsal fin rays modally I, 8; anal fin rays I, 8; pectoral fin rays modally 18; longitudinal scale series 30–32; predorsal scales 7–9; vertebral count 10 + 17 = 27; body always with six longitudinal pinkish orange to grayish brown lines from dorsal to ventral region in male; cheek spotless; branchiostegal membrane deep grayish with 6–7 long, transverse deep red stripes in male; chin always deep grayish; first dorsal fin with two long black blotches on membranes anterior to third spinous ray in male; second dorsal fin whitish with three to four horizontal rows of light spots in male; caudal fin base with a large blackish-brown spot; and pectoral fin with a horizontal, median blackish brown line. An artificial key to all five nominal species with a high vertebral count (27–29) from Zhejiang Province from China is also provided.     

Effects of repeated transvaginal ultrasound–guided aspirations performed in anestrous and cyclic mares on P4 and E2 plasma levels and luteal function

The aim of the present study was to verify how repeated ovum pick-up (OPU), performed in anestrous and cyclic mares, affect ovarian activity, measured by progesterone (P4) and 17ß-estradiol (E2) plasma levels. Ovum pick-up of all visible follicles was performed every 9 to 12 days, and four sessions were carried out during anestrous (A) and breeding season (BS). The number of aspirated follicles per mare at each session was not significantly different between the two periods (BS: 6.1 ± 2.4; A: 7.5 ± 4.4; P > 0.05), but the mean follicular diameter was significantly higher during BS (16.0 ± 7.1 vs. 10.2 ± 5.1 mm; P < 0.05); during A the number of aspirated follicles less than 15 mm in diameter resulted significantly higher than that registered in BS (5.1 ± 2.7 vs. 3.0 ± 1.8; P < 0.05). The total mean value of P4 was higher in BS than in A (6.3 ± 4.4 vs. 0.3 ± 1.8 ng/mL; P < 0.05), whereas the total mean level of E2 was not different between the two periods (3.8 ± 3.4 vs. 2.5 ± 2.7 pg/mL; P > 0.05). Estradiol plasma values resulted positively correlated, in A and BS, with diameter of follicles detected on the ovaries (R = 0.345 and R = 0.331, respectively), whereas a negative correlation was observed between P4 and follicular diameter in BS (R = −0.162). Both E2 and P4 presented a high individual variability during BS; in particular, in three of seven mares, P4 trend was compatible with a normal estrous cycle, and the interval between two consecutive peaks was 21 days. In two of seven mares, with CL at first OPU, P4 concentrations remained more than 3 ng/mL throughout the entire treatment period. Finally, in two of seven animals, P4 levels initially showed a similar pattern to that of a normal estrous cycle, then, after the second aspiration, they remained consistently higher than 3 ng/mL. When the procedure was carried out in cyclic animals, the influence of this technique on ovarian activity seemed to be related to individual variability although, according to progesterone values, structures observed on the ovaries after aspirations presented luteal function. Furthermore, the resumption of normal ovarian activity, after repeated OPU sessions, occurred in a period not much longer than the duration of a normal estrous cycle (25.4 ± 5.2 days). Data recorded during nonbreeding period showed that repeated OPU in anestrous mares do not affect ovarian activity and do not anticipate the resumption of ovarian cyclicity. However, based on the number of aspirated follicles in anestrous and cyclic mares, both types of subjects could be considered as oocyte donors.     

Inferences of body energy reserves on conception rate of suckled Zebu beef cows subjected to timed artificial insemination followed by natural mating

The influence of body condition score (BCS), rump fat thickness (RFAT), and live weight (LW), and the changes in these parameters during the interval from 165 of prepartum (i.e., 125 days of prior gestation) to 112 postpartum on first service conception and pregnancy rates were investigated in suckled Zebu (Bos indicus) beef cows (n = 266) subjected to timed artificial insemination (TAI) followed by natural mating. The aforementioned parameters were recorded at 165 ± 14 days (mean ± standard error) prepartum (concurrent with the weaning of previous calf), at parturition, and at 42 ± 7 days (at the onset of the synchronization of ovulation protocol), 82 ± 7 days (30 days after TAI), and 112 ± 7 days (60 days after TAI) postpartum. At the start of the breeding season (BS), cows were subjected to a synchronization of ovulation program for TAI. Bulls were placed with cows 10 days after TAI and remained until the end of the study (112 days postpartum). Cows with the highest BCS at parturition had an increased probability of first service conception rate at 60 days after TAI (P = 0.02) and a reduced probability of occurrence of pregnancy loss (P = 0.05). Also, cows had a greater likelihood of conceiving postpartum if they had greater RFAT and BCS at 165 ± 14 days prepartum (P = 0.01 and P = 0.03, respectively) and at parturition (P = 0.0007 and P = 0.003, respectively). Cows that had an increase in RFAT and BCS during the dry period (i.e., interval from weaning of the previous calf to parturition) also had a greater likelihood of conceiving (P = 0.03 and P = 0.06, respectively) during the BS. Among the different time points, RFAT and BCS at parturition had the largest impact on risk of conception during the BS. The LW was a poor predictor of conception during the BS (P = 0.11–0.68) except for LW at 165 ± 14 days prepartum (P = 0.01). Collectively, the findings indicated that the likelihood of conception during the BS was highest in cows that had an improvement in RFAT and BCS during the dry period. Therefore, assuring a good nutritional status in the dry period (BCS ≥ 3.0 at 165 ± 14 days prepartum and ≥3.25 at parturition) is an important aim to optimize the postpartum conception rate of suckled Zebu beef cows subjected to TAI followed by natural mating.     

Influence of type‐I Interferon receptor expression level on the response to type‐I Interferons in human pancreatic cancer cells

Pancreatic cancer is a highly aggressive malignancy with limited treatment options. Type‐I interferons (e.g. IFN‐α/‐β) have several anti‐tumour activities. Over the past few years, clinical studies evaluating the effect of adjuvant IFN‐α therapy in pancreatic cancer yielded equivocal results. Although IFN‐α and ‐β act via the type‐I IFN receptor, the role of the number of receptors present on tumour cells is still unknown. Therefore, this study associated, for the first time, in a large panel of pancreatic cancer cell lines the effects of IFN‐α/‐β with the expression of type‐I IFN receptors. The anti‐tumour effects of IFN‐α or IFN‐β on cell proliferation and apoptosis were evaluated in 11 human pancreatic cell lines. Type‐I IFN receptor expression was determined on both the mRNA and protein level. After 7 days of incubation, IFN‐α significantly reduced cell growth in eight cell lines by 5–67%. IFN‐β inhibited cell growth statistically significant in all cell lines by 43–100%. After 3 days of treatment, IFN‐β induced significantly more apoptosis than IFN‐α. The cell lines variably expressed the type‐I IFN receptor. The maximal inhibitory effect of IFN‐α was positively correlated with the IFNAR‐1 mRNA (P < 0.05, r = 0.63), IFNAR‐2c mRNA (P < 0.05, r = 0.69) and protein expression (P < 0.05, r = 0.65). Human pancreatic cancer cell lines variably respond to IFN‐α and ‐β. The expression level of the type‐I IFN receptor is of predictive value for the direct anti‐tumour effects of IFN‐α treatment. More importantly, IFN‐β induces anti‐tumour effects already at much lower concentrations, is less dependent on interferon receptor expression and seems, therefore, more promising than IFN‐α.