Chrysophycean stomatocysts from freshwater habitats of the Strømness Bay area, South Georgia, Antarctica

2000 ◽  
Vol 78 (1) ◽  
pp. 88-97 ◽  
Author(s):  
Bart Van de Vijver ◽  
Louis Beyens
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Working Group ◽  
South Georgia ◽  
Chrysophyte Cysts ◽  
Bay Area ◽  
Freshwater Habitats ◽  
Chrysophyte Stomatocysts ◽  
Scanning Electron

The chrysophycean stomatocyst flora of freshwater samples from the Strømness Bay area, located in the northern part of the Sub-Antarctic Island of South Georgia, was investigated, using scanning electron microscopy. A total of 59 stomatocyst morphotypes were recorded. Thirty-one of them were previously observed and 28 are described as new, following guidelines of the International Statospore Working Group. Since this is only the second study of chrysophyte cysts from South Georgia, this large number of new morphotypes is not surprising. The cyst flora show only a small resemblance to the stomatocyst flora found on mosses of the same area.Key words: chrysophyte stomatocysts, South Georgia, Sub-Antarctica.

scholarly journals Analysis of the type material of Achnanthes minutissima var. macrocephala (Bacillariophyta) and description of two new small capitate Achnanthidium species from Europe and the Himalaya

2019 ◽  
Vol 152 (2) ◽  
pp. 340-350
Author(s):  
Carlos E. Wetzel ◽  
Ingrid Jüttner ◽  
Smriti Gurung ◽  
Luc Ector
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Benthic Diatom ◽  
Original Material ◽  
Diatom Species ◽  
The World ◽  
Freshwater Habitats ◽  
The Himalaya ◽  
Scanning Electron ◽  
Achnanthes Minutissima

Background and aims – Two unknown benthic diatom species belonging to the genus Achnanthidium Kütz., and found in French and Nepalese freshwater habitats, were investigated. Both species are here described as new and compared with the original material of Achnanthes minutissima var. macrocephala Hust. [≡ Achnanthidium macrocephalum (Hust.) Round & Bukht.] from Indonesia. Methods – The morphology of three small and capitate Achnanthidium species was investigated using light microscopy (LM) and scanning electron microscopy (SEM). Key results – Achnanthidium coxianum sp. nov. (from the Himalaya) belongs to the group of species with hooked terminal raphe endings, while Achnanthidium peetersianum sp. nov. (from France) has variable terminal raphe endings which are usually slightly bent. Achnanthidium macrocephalum is a much rarer species and illustrations concerning its identity in the literature do not conform to the type studied here. Conclusions – The three species are similar in LM but clearly distinct in SEM. The shape of the areolae and terminal raphe endings separate the species. Achnanthidium macrocephalum has often been misidentified in studies from many areas of the world. It is similar to the new species in valve outline and in its small dimensions.

A new species of Cymbella (Cymbellaceae, Bacillariophyceae) from China, possessing valves with both uniseriate and biseriate striae

Phytotaxa ◽  
2018 ◽  
Vol 344 (1) ◽  
pp. 39 ◽  
Author(s):  
BING LIU ◽  
DAVID M. WILLIAMS ◽  
QINGYU LIU
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Structural Features ◽  
Freshwater Habitats ◽  
A New Species ◽  
Scanning Electron

Since scanning electron microscopy was used to study diatoms, many new ultra-structural features have been observed. This paper describes Cymbella distalebiseriata, a new species of Cymbella which has valves with biseriate striae near both apices of the valve and uniseriate striae at the valve centre. Comparison with some similar taxa supports its erection as new by the following combination of characters: two to three stigmata, puncta density 25–30 in 10 μm, and ca. 3 to 11 biseriate striae at both apices. C. distalebiseriata is epilithic and lives in freshwater habitats.

Achnanthidium sinense sp. nov. (Bacillariophyta) from the Wuling Mountains Area, China

Phytotaxa ◽  
2016 ◽  
Vol 284 (3) ◽  
pp. 194 ◽  
Author(s):  
BING LIU ◽  
SAÚL BLANCO ◽  
HUA LONG ◽  
JINGJING XU ◽  
XIAOYAN JIANG
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Middle Part ◽  
Central China ◽  
Similar Species ◽  
Large Species ◽  
Diatom Species ◽  
Freshwater Habitats ◽  
Scanning Electron

Achnanthidium sinense sp. nov., a new diatom species from the Wuling Mountains Area, central China, was studied by light and scanning electron microscopy. The valvar dimensions of this species are relatively large with respect to average Achnathidium taxa. The valves are narrowly lanceolate with round, acute apices. Only a few striae in the middle part of both valves can be resolved under light microscopy. The axial area of raphe valve is linear-lanceolate and the distal raphe fissures hook towards the same side of the valve. Striae are slightly radiate throughout both valves except at the apices of the raphe valve, where they become parallel or slightly convergent. The number of areolae in each stria on the rapheless valve is usually greater than that on the raphe valve (1–7 vs. 1–6). Around the central areas of both valves, sometimes short marginal striae composed of 1–3 areolae are present. Valve mantle possesses a row of slit-like areolae and 2–3 notches. A. sinense is compared with the similar species A. exile and other large species. A. sinense is epilithic and lives in freshwater habitats.

Adlafia sinensis sp. nov. (Bacillariophyceae) from the Wuling Mountains Area, China, with reference to the structure of its girdle bands

Phytotaxa ◽  
2017 ◽  
Vol 298 (1) ◽  
pp. 43 ◽  
Author(s):  
BING LIU ◽  
DAVID M. WILLIAMS ◽  
YONGDA OU
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Diatom Species ◽  
Freshwater Habitats ◽  
Secondary Side ◽  
Scanning Electron

Adlafia sinensis sp. nov., a new diatom species from the Wuling Mountains Area, China, has been studied using light and scanning electron microscopy. The valves are lanceolate with rostrate to subcapitate apices; the areolae are occluded by hymens outside and the both terminal raphe fissures hook towards the secondary side; the mantle is deep with c. 5–7 isolated striae not continuous from the valve face. Only one girdle band (valvocopula) occurs between the epivalve and hypovalve except at the apices of each frustule. The nature of the valvocopula is open because the two parts are not fused together. A. sinensis is compared with the all species in the genus Adlafia. A. sinensis is epilithic and live in freshwater habitats.

Chrysophycean stomatocysts from Xinjiang Province, China

Phytotaxa ◽  
2016 ◽  
Vol 288 (1) ◽  
pp. 41 ◽  
Author(s):  
WANTING PANG ◽  
QUANXI WANG
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Central Asia ◽  
Working Group ◽  
First Report ◽  
Low Diversity ◽  
Scanning Electron

Chrysophycean stomatocysts from 167 samples taken at 35 localities in Xinjiang Province, China were observed by scanning electron microscopy. The stomatocysts assemblages are characterized by low diversity and low abundance. Only 19 morphotypes were identified, of which nine are new to science. New stomatocysts were described following International Statospore Working Group (ISWG) guidelines. This is the first report of chrysophycean stomatocysts from Central Asia.

Chrysophycean stomatocysts from a karstic sink-hole in the vicinity of Staszów on the Małopolska Upland, Poland

2004 ◽  
Vol 82 (9) ◽  
pp. 1330-1337 ◽  
Author(s):  
Konrad Wołowski ◽  
Jolanta Cabała ◽  
Barbara A Zeeb
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Micrographs ◽  
Working Group ◽  
Scanning Electron Micrographs ◽  
Written Descriptions ◽  
First Time ◽  
Scanning Electron ◽  
Sink Hole

Chrysophycean stomatocysts from a karstic sink-hole near Staszów (Małopolska Upland, Poland) were investigated using scanning electron microscopy. Seven stomatocysts are described as new morphotypes and one is reported for the first time from Europe. These different cyst morphotypes (unornamented and ornamented stomatocysts) were recorded and documented using both light and scanning electron micrographs, and written descriptions are provided following International Statospore Working Group guidelines.Key words: stomatocysts, Chrysophyceae, new morphotypes, taxonomy, karstic sink-hole, Małopolska Upland, Poland.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

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).

Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

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