Climate-Related Variations in Autumn Cohort of Japanese Common Squid Todarodes pacificus

The Japanese common squid Todarodes pacificus is widely distributed in the Sea of Japan,the East China Sea and the Northwest Pacific Ocean,and is largely exploited by the Asia-Pacific countries.In this study,the impacts of regime shift of the Pacific Decadal Oscillation(PDO)during 1977-2015 on the autumn cohort of T.pacificus were assessed by examining the variations in vertical water temperatures at depths of 0 m(Temp_0 m),50 m(Temp_50 m)and 100 m(Temp_100 m)and the distribution pattern of preferred spawning ground(SSG).Spatial and temporal correlation analysis revealed that the PDO index exhibited a significantly negative relationship with vertical water temperatures at different depths and was negatively related to catch-per-unit-effort(CPUE)and stock biomass of T.pacificus.In addition,water temperatures in the specific three water layers were positively associated with CPUE.The PDO regime shift strongly affected the thermal condition and spawning ground of T.pacificus.Comparing to the negative PDO,the waters from the surface to the deep became cool in the positive PDO phase;correspondingly,the area of SSG largely contracted at different depths.Consequently,the CPUE and stock biomass of T.pacificus profoundly decreased.From the results it can be concluded that the PDO regime shift-driven changes in vertical thermal condition and SSG ranges can yield substantial impacts on T.pacificus abundance.

黑骨藤对Pristionchus pacificus线虫神经损伤的治疗实验

目的用Pristionchus pacificus线虫的神经热损伤模型,评价黑骨藤的神经修复药效。方法使用45℃的温针刺激Pristionchus pacificus线虫头部,复制神经损伤模型,用药后通过测定线虫的运动指数了解神经修复情况。结果黑骨藤的浓度在2～16 mg/ml这一区间内显示出良好的神经修复作用,存在明显的量效关系,浓度提高后黑骨藤能毒害线虫。结论黑骨藤能修复线虫因热刺激引起的神经损伤,为进一步研究黑骨藤的神经保护奠定基础。

超嗜热古菌Palaeococcus pacificus PolB DNA聚合酶和dUTPase在PCR反应中的应用

为了获取具有广泛适用性的DNA聚合酶,将深海热液区获得的超嗜热古菌Palaeococcus pacificus DY20341的Pol B DNA聚合酶和d UTPase进行原核表达和纯化,将得到的Pol B DNA聚合酶及d UTPase混合后用于扩增古菌、细菌和真核生物的基因.通过PCR反应成功地扩增了商业化Pfu DNA聚合酶所不能扩增的Palaeococcus pacificus DY2034的琼脂酶基因.由此可知,尽管商业化的DNA聚合酶多种多样,针对不同扩增目的片段所需的特异DNA聚合酶体系仍然是必要的,这是又一嗜热古菌B家族DNA聚合酶应用的报道.

Response of winter cohort abundance of Japanese common squid Todarodes pacificus to the ENSO events

The Japanese common squid Todarodes pacificus is an economically important species with one year lifespan,which is significantly influenced by climatic and environmental variability. According to the fishery data of the winter cohort of T. pacificus from 2003 to 2012, as well as environmental data and the Oceanic Ni？o index（ONI,which was defined by the sea surface temperature（SST） anomaly in the Ni？o 3.4 region）, variations in the SST,chlorophyll a（Chl a） concentration, suitable spawning area（SSA） and sea surface height anomaly（SSHA） on the spawning ground of T. pacificus were examined under the El Ni？o and La Nina conditions. Their influences on squid abundance（defined by catch per unit effort, CPUE） were further assessed. The results showed that seasonal changes were found in SST, Chl a and SSA on the spawning ground of T. pacificus. Correlation analysis suggested that annual CPUE was significantly positively correlated with Chl a and SSA（p〈0.05）, but had insignificant relationship with SST（p〉0.05）. Moreover, the El Ni？o and La Ni？a events tended to dominate the changes of SSA and Chl a concentration in the key area between 25°–29°N and 122.5°–130.5°E, driving the variability of squid abundance. However, this influence varied with the intensity of each anomalous climatic event： the weak El Ni？o event occurred, the spawning ground was occupied by waters with enlarged SSA but with extremely low Chl a concentration, leading to low squid recruitment, the CPUE then decreased; the moderate intensity of El Ni？o event resulted in shrunk SSA but with high Chl a concentration on the spawning ground, the squid recruitment and CPUE increased; the moderate intensity of La Ni？a events yielded elevated SSA and high Chl a concentration on the spawning ground, the squid recruitment and CPUE dramatically increased. Our findings suggested that the ENSO events played crucial effects on the incubating and feeding conditions of the winter cohort of T. pacificus during the spawning season and ultimately affected its abundance.

北太平洋鱿鱼缠卵腺抗氧化酶解寡肽的制备

为探讨北太平洋鱿鱼(Todarodes pacificus)缠卵腺酶解寡肽的制备和抗氧化活性,以北太平洋鱿鱼缠卵腺为原料,选择碱性蛋白酶进行酶解,以水解度和DPPH自由基清除率为指标,经单因素和正交试验方法获得最佳酶解条件,超滤得到不同分子段多肽,通过测定还原能力、DPPH清除率、Fe^(2+)螯合能力、OH自由基清除率、超氧阴离子清除率评价不同分子量酶解多肽的抗氧化性,得出最佳分子段;采用琼脂糖凝胶G-25对最佳分子段进行分离,检测各峰对DPPH清除能力,得出最佳峰段后经HPLC进一步分离获得单一组分,由氨基酸测序仪进行N端降解测序得出目标肽序列。结果表明,碱性蛋白酶的酶解条件为温度50℃、酶解时间7 h、加酶量3 500 U/g、pH 9.0、料液比1∶6。经超滤得到的3～5 ku分子段抗氧化活性最强,经琼脂糖凝胶G-25分离得到3个峰,其中峰Ⅰ组分对DPPH清除率最好,当浓度为0.5 mg/m L时其DPPH的清除率为61.87%。经HPLC纯化得到单一峰,氨基酸序列测定为Ala-Tyr-Ala-Ser-Ser,相对分子质量为497.50。北太平洋鱿鱼缠卵腺酶解寡肽有较好的抗氧化活性。

Infection Prevalence of <i>Borrelia burgdorferi</i>in Ticks Collected from Songbirds in Far-Western Canada

Worldwide, wild birds play a vital role in the dispersal of ticks that harbour tick-borne pathogens, including Borrelia burgdorferi, the Lyme disease bacterium. Using PCR testing, we found 124 (31%) of 405 ticks (4 species), which were collected from 21 species of birds in far-western Canada, to be infected with B. burgdorferi. Transstadial transmission of B. burgdorferi occurred from larva to nymph, plus nymph to adult, in the avian coastal tick, Ixodes auritulus, collected from songbirds in British Columbia (B.C). Collectively, all 3 motile life stages (larva, nymph, adult) of this tick had an infection prevalence of 31% for B. burgdorferi, which suggests vector competency. A Pacific Wren was highly infested with I. auritulus immatures, and 20 (44%) of 45 ticks (2 nymphs, 43 larvae) were infected with B. burgdorferi. This heavy infestation shows the high potential to initiate a new population of ticks and to disseminate Lyme spirochetes. Epidemiologically, B. burgdorferi-infected I. auritulus larvae collected from the Spotted Towhee, Swainson’s Thrush, Pacific Wren, and Fox Sparrow suggest that these avian hosts act as reservoirs for B. burgdorferi. In this study, the western blacklegged tick, Ixodes pacificus, and Ixodes spinipalpis played a limited role in the enzootic transmission cycle of B. burgdorferi along coastal B.C. We document the first record of I. spinipalpis on a bird in Alberta. Because songbirds widely disperse Lyme disease vector ticks, primary health providers and the general public must be vigilant that outdoors people may be bitten by B. burgdorferi-infected ticks throughout far-western Canada.

Natural parasites in conjunction with behavioral and color traits explain male agonistic behaviors in a lizard

Male competition conforms to a cost-benefit model,because while aggression may increase reproductive prospects,it can also increase the risk of injury.We hypothesize that an additional cost in aggressive males would be an increase in parasite load associated with a high energy investment into sexual competition.Some of these infections,in turn,may downmodulate the level of host aggression via energetic trade-offs.We staged dyadic male contests in the lab to investigate the relationships of multiple parasites with the agonistic behavior of lizard hosts,Sceloporus occidentalis.We also included both color and behavioral traits from opponents in the analyses because(1)color patches of lizards may serve as intraspecific signals used by conspecifics to assess the quality of opponents,and(2)contests between male lizards fit classical models of escalated aggression,where lizards increase aggression displays in response to an opponent's behavior.The results conform to our hypothesis because male lizards displayed more pushups when they had more ticks.Moreover,some parasites may modulate the levels of aggression because lizards infected by hematic coccidians performed fewer pushups.Interestingly,lizards also displayed fewer pushups when both the chroma and size of the opponent's blue patch were greater.The results thus also supported the role of the blue patch of s.occidentalis as a sexual armament,because it contributed to the deterrence of aggression from opponent lizards.We revealed that natural parasitic infections in lizard hosts can contribute to their agonistic behavior.We encourage future studies to account for parasites in behavioral testswithlizards.