Transmission electron microscopy of marine crustacean eggs

Hubble, Suzanne K.; Kirby, Richard R.

doi:10.1163/156854007781360658

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…Specimen preparation for transmission electron microscopy followed [26] in detail. Freshly collected specimens were fixated in a 2.5% glutaraldehyde solution in a Cacodylate buffer at pH 7.4.…”

Section: Methodsmentioning

confidence: 99%

Circular Polarization of Transmitted Light by Sapphirinidae Copepods

2014

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Circularly polarized light, rare in the animal kingdom, has thus far been documented in only a handful of animals. Using a rotating circular polarization (CP) analyzer we detected CP in linearly polarized light transmitted through epipelagic free living Sapphirina metallina copepods. Both left and right handedness of CP was detected, generated from specific organs of the animal's body, especially on the dorsal cephalosome and prosome. Such CP transmittance may be generated by phase retardance either in the muscle fibers or in the multilayer membrane structure found underneath the cuticle. Although the role, if any, played by circularly polarized light in Sapphirinidae has yet to be clarified, in other animals it was suggested to take part in mate choice, species recognition, and other forms of communication.HighlightsPlanktonic Sapphirinidae copepods were found to circularly polarize the light passing through them. Circular polarization may be created by unique, multilayered features of the membrane structure found under their cuticle or by organized muscle fibers.

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Section: Methodsmentioning

confidence: 99%

Circular Polarization of Transmitted Light by Sapphirinidae Copepods

2014

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“…Toda and Hirose (1991) even propose that the multilayer membrane consists of seven or eight layers. Additionally, Hubble and Kirby (2007) described a single-layer chorion compared with a thick three-layered chorion in subitaneous or diapause eggs of A. tonsa. Dharani and Altaff (2004) describe a three-layered outer chorion for the subitaneous eggs and a highly complex, thick, and four-layered outer chorion for the diapause eggs of the freshwater species Sinidiaptomus (Rhinediaptomus) indicus.…”

Section: Distinguishing Characteristics Of Resting Egg Categoriesmentioning

confidence: 99%

Copepod Embryonic Dormancy: “An Egg Is Not Just an Egg”

Hansen

2019

The Biological Bulletin

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Long-lasting embryonic dormancy in invertebrates defies our understanding of what constitutes life because, for example, eggs of some copepods can delay hatching for decades or even centuries. Copepods, often millimeter-sized crustaceans, are some of the most numerous multicellular organisms on earth and are key organisms in most aquatic food webs. Some important free-living marine and estuarine species overwinter or oversummer by arrested embryogenesis in dormancy. The present contribution discusses the complex mechanisms behind embryonic dormancy by compiling knowledge from the 42 calanoid copepods from the superfamily Centropagoidea with well-described embryonic dormancy, which has been of scientific interest for decades. However, the determination of categories of copepod resting eggs-that is, diapause and quiescence, transitions between categories, the mechanisms controlling arrested development by the embryos, and how they interact with their surroundings-is not fully understood. Moreover, a clear link between the presence of the free-swimming population and their resting eggs in sediments is still not convincingly demonstrated. Here I evaluate the relative significance of potential cues driving the production of and the phase shift between egg categories. Understanding the initiation and termination of embryonic dormancy is of great importance for fundamental science-that is, population and food web ecology as well as climate science, aquaculture live feed, and ballast water research. Molecular techniques are developing rapidly, especially within health sciences, thus providing relevant tools applicable for plankton research. Here I suggest that applying molecular methods in addition to traditional physiological approaches in future research will lead to greater understanding of copepod embryonic dormancy, one of nature's wonders.

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“…As technology advanced further, transmission electron microscopy (TEM) began to be employed for observing the internal ultrastructure of objects of study. For instance, TEM has been used to study the ultrastructure of fertilized eggs and early crustacean embryos (Hubble and Kirby, 2007). In addition, confocal laser scanning microscopy (CLSM) has become one of the popular instruments to build up 3D images for cell analysis.…”

Section: Introductionmentioning

confidence: 99%

Observations on the embryonic development of the mud crab, Scylla paramamosain

Xu,

Ma,

Zhang

et al. 2023

Front. Mar. Sci.

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To investigate the embryonic development of the mud crab Scylla paramamosain, we analyzed three critical parameters: egg color of, embryo morphology (through conventional and laser scanning confocal microscopy), and the distribution of cell divisions. During embryonic development, the egg color exhibited a progressive transition, shifting from orange to reddish-orange, then to brown, before ultimately darkening to black. Each embryo displayed a spherical shape, measuring approximately 280 μm in diameter, characterized by a smooth surface devoid of any depressions. The embryonic cell division was in the form of mixed oogenesis, comprised of complete division in the early stage, spiral oogenesis in the middle stage and surface division in the late stage. It is noteworthy that the blastopore appeared at the position where the transparent area and cell aggregation just appeared under the microscope, and the blastomere was a characteristic of the embryo entering the gastrulation stage. After entering the gastrulation stage, the cells aggregated towards the blastopore and formed two symmetrical cell clusters, which formed a V-shape with the void of the classic blastopore. When the transparent region occupied approximately 1/5 of the embryo’s volume, the embryo entered the nauplius stage, and the thoracic and abdominal armor, as well as the optic lobe and abdominal limb primordia, could be clearly distinguished. The appearance of the compound eye pigment band indicated the stage of compound eye pigment formation. At this time, the transparent area accounted for 1/4 of the embryo and a large number of ganglia appeared. The change of the compound eye pigment band from red to black was also one of the reasons for the blackening of the egg color of the crabs. The data obtained through this study have potential applications in the determination of embryonic development status and obtaining of high-quality seeds for S. paramamosain culture.

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Transmission electron microscopy of marine crustacean eggs

Cited by 7 publications

References 24 publications

Circular Polarization of Transmitted Light by Sapphirinidae Copepods

Circular Polarization of Transmitted Light by Sapphirinidae Copepods

Copepod Embryonic Dormancy: “An Egg Is Not Just an Egg”

Observations on the embryonic development of the mud crab, Scylla paramamosain

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