The epithelial cytotypes of hepatopancreas in the Chinese mitten crab Eriocheir sinensis (Decapoda, Varunidae)

Crustaceana ◽  
2017 ◽  
Vol 90 (3) ◽  
pp. 253-262 ◽  
Author(s):  
Hui Zhang ◽  
Shengwei Zhong ◽  
Qinyong Fan ◽  
Pengcheng Yu ◽  
Tingting Ge ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Eriocheir Sinensis ◽  
Embryonic Cells ◽  
Chinese Mitten Crab ◽  
Septate Junctions ◽  
Large Vacuole ◽  
Transmission Electron ◽  
Mitten Crab ◽  
F Cells

The Chinese mitten crab,Eriocheir sinensis, is an economically important crustacean. However, the hepatopancreas structure of the crab has not been fully disclosed. Here, we employed light microscopy and transmission electron microscopy to identify the epithelial cytotypes of the hepatopancreas. The hepatopancreas consisted of four epithelial cytotypes, which were B (blister-like), R (resorptive), F (fibrillar), and E (embryonic) cells. B cells had club-shaped nuclei, scant cytoplasm, and contained some small vacuoles and one extremely large vacuole. Both R and F cells were columnar, and F cells were separated by two to three serial R cells. R cells contained small vacuoles, but had no extremely large vacuole in the cytoplasm. Two neighbouring R cells established contact by septate junctions. Many microvilli were present on the surface of the plasmalemma of R cells. Endocytotic vesicles were frequently observed in apical regions of the R cells. F cells were hyperbasophilic and argyrophilic, and contained abundant rough endoplasmic reticulum. E cells were small and contained scant cytoplasm and we rarely observed organelles in these cells. In addition, many vesicae were present in the lumen of the hepatopancreatic tubules.

scholarly journals Gliocyte and synapse analyses in cerebral ganglia of the Chinese mitten crab, Eriocheir sinensis: ultrastructural study

2016 ◽  
Author(s):  
H. Zhang ◽  
P. Yu ◽  
S. Zhong ◽  
T. Ge ◽  
S. Peng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Eriocheir Sinensis ◽  
Type I ◽  
Aquatic Species ◽  
Histological Findings ◽  
Chinese Mitten Crab ◽  
Cerebral Ganglia ◽  
Transmission Electron ◽  
Mitten Crab ◽  
Nerve System

The Chinese mitten crab Eriocheir sinensis is an economically important aquatic species in China. Many studies on gene structure, breeding, and diseases of the crab have been reported. However, knowledge about the organization of the nerve system of the crab remains largely unknown. To study the ultrastructure of the cerebral ganglia of E. sinensis and to compare the histological findings regarding the nerve systems of crustaceans, the cerebral ganglia were observed by transmission electron microscopy. The results showed that four types of gliocytes, including type I, II, III, and IV gliocytes were located in the cerebral ganglia. In addition, three types of synapses were present in the cerebral ganglia, including unidirectional synapses, bidirectional synapses, and combined type synapses. 

scholarly journals Autophagy and apoptosis in starved and refed Neocaridina davidi (Crustacea, Malacostraca) midgut

2019 ◽  
Vol 97 (4) ◽  
pp. 294-303 ◽  
Author(s):  
A. Włodarczyk ◽  
S. Student ◽  
M. Rost-Roszkowska
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
B Cells ◽  
Apoptotic Cells ◽  
Reserve Material ◽  
Transmission Electron ◽  
F Cells ◽  
Immunohistochemical Methods ◽  
D Cells ◽  
Experimental Group

Adult specimens of the freshwater shrimp Neocaridina davidi Bouvier, 1904 (Crustacea) were starved for 7, 14, and 21 days. Specimens from the first and second experimental group were collected for the studies. The majority of animals starved for 21 days died. Additionally, some specimens from each group were refed for 4, 7, and 14 days. The epithelium of the midgut, which is composed of the intestine and hepatopancreas, was analyzed. While the epithelium of the intestine is formed by D- and R-cells, the epithelium of the hepatopancreas has R-, B-, and F-cells. Autophagy and apoptosis in the midgut epithelium were analyzed using transmission electron microscopy and immunohistochemical methods. These processes were only observed in the D-cells of the intestine and the F- and B-cells of the hepatopancreas. Starvation led to a reduction in the amount of reserve material in the B-cells. Although this process activated autophagy in both regions of the midgut, the intestine and hepatopancreas, after refeeding, the level of autophagy decreased. Starvation caused an increase in the apoptotic cells in both organs, while the refeeding caused a decrease in the number of apoptotic cells in both organs analyzed. Refeeding after periods of starvation caused an accumulation of reserve material in the hepatopancreas.

A spiroplasma associated with tremor disease in the Chinese mitten crab (Eriocheir sinensis)

Microbiology ◽  
2004 ◽  
Vol 150 (9) ◽  
pp. 3035-3040 ◽  
Author(s):  
Wen Wang ◽  
Bohai Wen ◽  
Gail E. Gasparich ◽  
Ningning Zhu ◽  
Liwen Rong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Light And Electron Microscopy ◽  
Eriocheir Sinensis ◽  
Rrna Gene ◽  
Chinese Mitten Crab ◽  
Mitten Crab ◽  
The 16S Rrna Gene

An epidemic of tremor disease has been a serious problem in Chinese mitten crabs, Eriocheir sinensis, in China in recent years. The disease-causing agent was previously considered to be a rickettsia-like organism. Here, analysis of the 16S rRNA gene sequence, light and electron microscopy and cultivation in vitro were used to identify the agent. Sequence analysis of the 16S rRNA gene found it to have 98 % identity with that of Spiroplasma mirum. The agent was able to be passed through membrane filters with pores 220 nm in diameter and could be cultivated by inoculating the yolk sac of embryonated chicken eggs and M1D medium. Rotary motion and flexional movement were seen by light microscopy, and electron microscopy showed that the organism had a helical morphology and lacked a cell wall. The organism produced small colonies with a diameter of 40–50 μm after 17–25 days of incubation on solid M1D medium. The agent was found in blood cells, muscles, nerves and connective tissues of crabs inoculated with a filtrate of yolk sacs or with cultures grown in M1D medium, and it was similar in structure to those grown in eggs and cultivation broth. Disease was reproduced by experimental infection with the cultivated organisms. This study has demonstrated that the causative agent of tremor disease in the Chinese mitten crab is a member of the genus Spiroplasma. This is believed to be the first time a spiroplasma has been found in a crustacean. These findings are not only significant for studies on pathogenic spiroplasmas, but also have implications for studies of freshwater ecology.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

1974 ◽  
Vol 32 ◽  
pp. 546-547
Author(s):  
R.R. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Composite Materials ◽  
Great Difficulty ◽  
Ion Milling ◽  
Transmission Electron ◽  
Ion Damage ◽  
Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

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