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The effects of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus (Copepoda: Calanoida)
XU Donghui, LIU Guangxing
2014, 33(9): 133-138. doi: 10.1007/s13131-014-0524-4
Keywords: DDT, Sinocalanus tenellus, survival, reproduction, feeding, respiration, antioxidant enzyme
DDT (dichloro-diphenyl-trichloroethane) as a type of organochlorine pesticides, is an important component of pesticides pollution whose impact on the marine ecosystem is urgently to be evaluated. To investigate the biological effects of DDT on the marine ecosystem, copepods being the main contributor of secondary productivity in the marine ecosystem, were selected as target animals. The influence of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus (S. tenellus) was analyzed and the antioxidant enzymes activities in the individuals were measured under different exposure concentrations of DDT. The 48 h median lethal concentration (LC50) and 96 h LC50 of DDT to S. tenellus were 5.44 and 2.50 μg/dm3, respectively. The filtration rates, grazing rates, and respiration of S. tenellus decreased apparently with increased DDT concentrations. Under lower concentration (<625 ng/dm3) of DDT, the activities of the antioxidant enzymes, including superoxide dismutase and catalase in the animals increased significantly compared with those in the animals without any exposure to DDT, which suggested that the antioxidant enzymes can protect the animals from oxidative damage. However, the activity of the antioxidant enzyme decreased when the animals were exposed to higher concentration (1 250-2 500 ng/dm3) of DDT. The survival rate of both females and males was reduced when they were exposed to DDT less than 250 ng/dm3, but females showed higher survival rate than males when they are under the same concentration. The hatching ratio and the egg diameters of S. tenellus decreased significantly when they were exposed to DDT with a concentration of 25 and 250 ng/dm3, however, the cumulative egg production did not show any significant variation when the animals were exposed to the above DDT concentration. These data in the preset study suggested that exposure to DDT can cause the variation of the species composition of copepods, and further affect the marine ecosystem.
Grazing and performance of the copepod Pseudodiaptomus poplesia on a Chinese strain of Aureococcus anophagefferens
HE Xuejia, HAN Didi, HAN Liuyu, LU Songhui
2018, 37(4): 69-76. doi: 10.1007/s13131-018-1168-6
Keywords: A. anophagefferens, copepod, grazing, growth, development, reproduction
Brown tides have recurred in estuary areas globally, but trophic interactions between the causative species Aureococcus anophagefferens and planktonic copepods remain poorly understood. In this study, we investigated performance (ingestion, growth, development and reproduction) of the planktonic copepod, Pseudodiaptomus poplesia, offered either mono-algal or mixed-algal diets containing a Chinese strain of A. anophagefferens. A typical Michaelis-Menten pattern existed between ingestion rate and food level when copepod fed on the mono-algal diet of this species. Nauplii exhibited the highest maximum ingestion rate (Imax) than copepodids and adult females. In addition, Imax value was higher in nauplii feeding on A. anophagefferens than on Skeletonema costatum. When fed mixtures of A. anophagefferens and S. costatum, P. poplesia selected against A. anophagefferens cells, but less strongly at the naupliar stage. Nauplii did not undergo metamorphosis and died at late naupliar stages feeding on A. anophagefferens alone, similar to those under starvation. Furthermore, the presence of A. anophagefferens greatly reduced the reproduction rate of females in mixtures but did not influence the growth rate of copepodids. These results suggest that P. poplesia nauplii may exert grazing pressure on A. anophagefferens population during a brown tide, which, however, may not be persistent because of copepod population decline.
Effects of nutrient limitations on three species of zooplankton
CHEN Lei, LI Chaolun, ZHOU Konglin, SHI Yongqiang, LIU Mengtan
2018, 37(4): 58-68. doi: 10.1007/s13131-017-1122-z
Keywords: zooplankton, nutrient, growth, reproduction, stoichiometric homoeostasis
Nutrient imbalance-a mismatch in nutrient ratios between the available food supply and the demands of consumers-has the potential to be transported up food chains, exposing zooplankton to nutrient limitations. In this study, the response of Calanus sinicus (copepod), Moina mongolica (cladocera), and Brachionus plicatilis (rotifer) to nutrient-limited (no-limited, P-limited, and N-limited) food were evaluated from the perspective of growth, reproduction, and stoichiometric homoeostasis. The results indicated that the growth of three species was suppressed under nutrient-limited (especially P-limited) conditions. However, the effect of nutrient limitations on their reproduction was species-specific. For C. sinicus, the dietary UFA (unsaturated fatty acid) as a major phospholipid component affected their egg production and total FA supporting energy promoted the hatchability of eggs. Furthermore, excess carbon in the diet promoted egg production but reduced hatching success. For M. mongolica, nutritional (P and UFA) and energy (total FA) support affected their fecundity. B. plicatilis fecundity exhibited the same pattern of growth (no-limited>N-limited>P-limited). In terms of stoichiometric homeostasis, B. plicatilis's elemental compositions were less likely to be affected by nutrient limitations than M. mongolica. We suggest that the effects of nutrient imbalances could potentially become an evolutionary force affecting ecosystem structure and stability in eutrophic waters.
Glycogen content relative to expression of glycogen phosphorylase (GPH) and hexokinase (HK) during the reproductive cycle in the Fujian Oyster, Crassostrea angulata
ZENG Zhen, NI Jianbin, KE Caihuan
2015, 34(6): 66-76. doi: 10.1007/s13131-015-0639-2
Keywords: Crassostrea angulate, GPH, HK, glycogen metabolism, reproduction
Glycogen, a polymer of glucose, is an important means of storing energy. It is degraded by glycogen phosphorylase (GPH) and hexokinase (HK), glycogen phosphorylase, and hexokinase cDNAs (Ca-GPH and Ca-HK, respectively), which encode the primary enzymes involved in glycogen use, cloned and characterized and used to investigate the regulation of glycogen metabolism at the mRNA level in Crassostrea angulata. Their expression profiles were examined in different tissues and during different reproductive stages. Full-length cDNA of GPH was 3 078 bp in length with a 2 607 bp open reading frame (ORF) predicted to encode a protein of 868 amino acids (aa). The full-length HK cDNA was 3 088 bp long, with an ORF of 1 433 bp, predicted to encode a protein of 505 aa. Expression levels of both genes were found to be significantly higher in the gonads and adductor muscle than in the mantle, gill, and visceral mass. They were especially high in the adductor muscle, which suggested that these oysters can use glycogen to produce a readily available supply of glucose to support adductor muscle activity. The regulation of both genes was also found to be correlated with glycogen content via qRT-PCR and in situ hybridization and was dependent upon the stage of the reproductive cycle (initiation, maturation, ripeness). In this way, it appears that the expression of Ca-GPH and Ca-HK is driven by the reproductive cycle of the oyster, reflecting the central role played by glycogen in energy use and gametogenic development in C. angulata. It is here suggested that Ca-GPH and Ca-HK can be used as useful molecular markers for identifying the stages of glycogen metabolism and reproduction in C. angulata.
STUDIES ON THE MARINE CLADOCERA OF CHINA Ⅲ. REPRODUCTION
ZHENG ZHONG, CAO WENQING
1986(2): 271-283.
Studies are made on the reproduction of two common marine Cladocera (Penilia avirostris,Evadne ter-gestina) of China with emphasis on the fertility of parthenogenetic females (P♀).A positive correlation exists between the fertility and the size of the same species; but no such correlation is found between the fertility and the size of different species.The fertility is,on the whole,higher in summer and is related to the seasonal fluctuation of population density,both attaining their maximum period in summer; but the former appears about half a month earlier than the latter,A brief account is given of the sexual reproduction,including the respective size and the seasonal variation of sexual individuals (S♀,♂) together with a note on the sex-ratio and the characteristics of resting egg.
Morphology, reproduction, ecology and isoenzyme electrophoresis of Capitella complex in Qingdao
Wu Baoling, Qian Peiyuan, Zhang Songling
1988(3): 442-458.
Morphology, reproduction, ecology and isoenzyme electrophoresis of a Capitella complex in Qingdao were examined from 1983 to 1984. We determined that the Capitella complex in Qingdao was composed of at least three sibling species:Capitella cf capitata, Capitella sp. I and Capitella sp. Ⅱ. Although these three species are very similar in morphology, they differ in:three kinds of isoenzyme electrophoresis, staining reactions, developmental pattern, larval morphology and dispersal, reproductive strategies, breeding season and population ecology. In addition, they show a series of minor quantitative variations in adult morphology, especially in number and morphology of setae. Such differences can be detected only at the population level. Some ecological data such as density, growth rate, mortality and sex distribution are also provided in this paper.
Effects of biogenic amines on the testicular development in mud crabs Scylla serrata
YE Haihui, HUANG Huiyang, LI Shaojing, WANG Guizhong, LI Qifu
2006(2): 119-124.
Keywords: biogenic amines, Scylla serrata, neuroendocrine organs, androgenic gland, reproduction
The regulation of three biogenic amines over the reproductive neuroendocrine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation.The testicular index, the ratio of the mature sections in testes, and the ratio of Type B cells in androgenic gland were taken as the quantitative indexes.The in vivo injections indicated that:5-HT can significantly promote the testicular development and the secretion of the androgenic gland in S.serrata; DA can inhibit the testicular development, but no influence on the secretion of the androgenic gland was found; no significant difference was observed between the OA-injected group and the concurrent control group.In vitro incubations showed that:5-HT can stimulate the secretion of the brain and the thoracic ganglia, thus accelerating that of the androgenic gland; however, neither OA nor DA showed any significant influence on the secretion of the brain and the thoracic ganglionic mass.As to the optic ganglia, the three biogenic amines hardly have any effect on its secretion.It is the first time to report the regulation of biogenic amines over the reproductive neuroendocrine of male crustaceans through vitro experiments.Results corroborate that 5-HT activates the brain and the thoracic ganglia to secret GSH first, then promote the testicular development through the activity of the androgenic gland.
Changes of melatonin and its receptors in synchronizing turbot (Scophthalmus maximus) seasonal reproduction and maturation rhythm
Chunyan Zhao, Shihong Xu, Yifan Liu, Chengcheng Feng, Yongshuang Xiao, Yanfeng Wang, Qinghua Liu, Jun Li
2022, 41(1): 84-98. doi: 10.1007/s13131-021-1923-y  Published:2022-01-10
Keywords: turbot, brain, melatonin, melatonin receptors, seasonal reproductive development
In most fish, reproduction is seasonal or periodic under the suitable conditions. In turbot (Scophthalmus maximus) farms, one of the most economically important marine flatfish species, changes in daylength could cause changes in the spawning time. In this study, to characterize the regulation of reproductive physiology following light signals, three melatonin receptors (Mtnr) investigated in turbot were named smMtnr1, smMtnr2, and smMtnr1c. Distinct expression profiles demonstrated that Mtnr mRNAs were concentrated in the brain (as detected in the hypothalamus (Hy) and mesencephalon (Me)), gonad and eye. The most abundant Mtnr1 and Mtnr2 mRNA expression levels were detected in the central nervous system at the beginning of the breeding season, suggesting that Mtnr1 and Mtnr2 may play vital roles in the regulation of turbot gonadal development. In addition, the melatonin profiles gradually increased and reached to the highest level at the spawning stage, indicating that melatonin is a potent hormone in the regulation of fish oocyte growth and maturation. The results of this study suggested that melatonin is the primary factor that transduces the light signal and regulates the physiological functions of turbot seasonal reproduction. Moreover, the results of this study may establish a foundation for further research seeking to identify fish melatonin receptors involved in the gonadal development and gamete maturation.
Circadian rhythms in the growth and reproduction of the brown alga Undaria pinnatifida and gametogenesis under different photoperiods
ZHANG Zhihuai, PANG Shaojun
2007(4): 104-111.
Keywords: Undaria pinnatifida, circadian rhythm, egg release, gametogenesis
Circadian growth rhythm of the juvenile sporophyte of the brown alga Undaria pinnatifida was measured with the computer-aided image analysis system in constant florescent white light under constant temperature (10℃). The growth rhythm persisted for 4 d in constant light with a free-running period of 25.6 h. Egg release from filamentous gametophytes pre-cultured in the light-dark regime was evaluated for six consecutive days at fixed time intervals in constant white light and 12 h light per day. Egg release rhythm persisted for 3 d in both regimes, indicating the endogenous nature. Temporal scale of egg release and gametogenesis in 18, 16, 12 and 8 h light per day were evaluated respectively using vegetatively propagated filamentous gametophytes. Egg release occurred 2 h after the onset of dark phase and peaked at midnight. Evaluation of the rates of oogonium formation, egg release or fertilization revealed no significant differences in four light-dark regimes, indicating the great plasticity of sexual reproduction. No photoperiodic effect in gametogenesis in terms of oogonium formation and egg release was found, but fertilization in short days was significantly higher than in long days. Results of this investigation further confirmed the general occurrence of circadian rhythms in intertidal seaweed species.
Two-stage reproduction derived from cells of thallus could directly contribute to seeds for green tidal algal Enteromorpha(Ulva) prolifera/clathrata bloom, with disclosure of their ephemeral trait
Bingxin Huang, Lanping Ding, Yao Zhang, Youxuan Guo, Junxia Liang, Yanqi Xie, Yue Chu
2023, 42(9): 101-112. doi: 10.1007/s13131-023-2158-x  Published:2023-09-01
Keywords: green tidal algae, Yellow Sea, opportunistic trait, on-year and off-year, early infantile, alternation of generations, prediction on the occurrence process
Green tidal algal Enteromorpha species complete their life cycles by the isomorphic alternation of generations. The provenance of green tide caused by them in the western Yellow Sea has been disputed. The cell reproduction derived from adult thallus was observed on E. clathrata collected from Shantou City, Guangdong Province in this study. Subsequently, it further found that E. proliferia collected from Qingdao City, Shandong Province and Qinhuangdao City, Hebei Province, produced reproductive cells by somatic cells of its early infantile thallus or branch. The latter is functionally similar to that the seedlings of red alga Porphyra yezoensis produce the monospores, and could exquisitely explain the ephemeral or opportunistic trait and environmental adaptation ability of Enteromorpha species. Changes in growth conditions may induce the two types of cell reproduction. They contribute to the bloom, and can effectively reveal the seasonally occurring large-scale and on-year and off-year phenomenon. The latter may have played a decisive role in its formation. This paper analyses the legal status of the species name, the type of generation during bloom, ephemeral traits, the role of microscopic propagule, the area of origin, on-year and off-year phenomenon, early warning and prevention and control of the species, and so on. On this basis, further study on the influence of environmental factors on cell reproduction of early infantile thalli or branches will achieve a positive effect for early warning and prevention and control of the green tidal algal bloom.
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