Distribution of silica-scaled Chrysophyceae (Paraphysomonadaceae and Mallomonadaceae) in Australian inland waters

1985 ◽  
Vol 36 (6) ◽  
pp. 839 ◽  
Author(s):  
RL Croome ◽  
PA Tyler
Keyword(s):  
Electron Microscopy ◽  
Inland Waters ◽  
Population Densities ◽  
Species Numbers ◽  
Wide Range ◽  
Freshwater Habitats ◽  
Dystrophic Lakes ◽  
Australian Freshwater ◽  
First Time ◽  
Eleven Species

Thirty-two species of silica-scaled Chrysophyceae of the genera Spiniferomonas, Chrysosphaerella and Paraphysomonas, belonging to the Paraphysomonadaceae Preisig & Hibberd, 1983, and Mallomonas, Mallomonopsis and Synura, belonging to the Mallomonadaceae (Diesing, 1866) Preisig & Hibberd, 1983, are recognized by electron microscopy from a wide range of Australian freshwater habitats, from tropical to temperate regions, and from a range of trophic types of lake. Eleven species are reported from Australia for the first time, and three from the Southern Hemisphere for the first time. Although most of the species are of worldwide occurrence, several are as yet known only from Australia. Several highly dystrophic lakes in Tasmania are particularly rich in species numbers and in population densities.

Revision of the genus Platygerris White, 1883 (Hemiptera: Heteroptera: Gerridae), with descriptions of two new species from Colombia

2020 ◽  
Vol 51 (4) ◽  
pp. 672-695 ◽  
Author(s):  
Carla Fernanda Burguez Floriano ◽  
Fredy Molano-Rendón ◽  
Irina Morales ◽  
Felipe Ferraz Figueiredo Moreira ◽  
Pitágoras da Conceição Bispo
Keyword(s):  
Electron Microscopy ◽  
New Species ◽  
Identification Key ◽  
True Bugs ◽  
Two New Species ◽  
Cuticular Structure ◽  
Freshwater Habitats ◽  
First Time

Platygerris White comprises true bugs that inhabit the surface of water in moderate to fast-flowing freshwater habitats. This genus differs from Cylindrostethus Mayr and Potamobates Champion (Gerridae: Cylindrostethinae) by having a short and flattened body; the mandibular and maxillary plates fused; and the omphalium, lateral groove, and lateral evaporatorium of the scent apparatus inconspicuous. In this paper, we redescribe Platygerris, describe two new species from Colombia, and redescribe P. asymmetricus Hungerford, P. caeruleus Champion and P. depressus White. In addition, we present an updated identification key to the species of the genus. For the first time, the cuticular structure is described for the genus based on electron microscopy.

scholarly journals New data to the knowledge on the Harpacticoida (Crustacea, Copepoda) fauna in Poland

2016 ◽  
Vol 59 (2) ◽  
pp. 87-98
Author(s):  
Maciej KARPOWICZ ◽  
Keyword(s):  
Inland Waters ◽  
North Eastern ◽  
Freshwater Habitats ◽  
Taxonomic Studies ◽  
First Time ◽  
Distinguishing Features

Harpacticoida is the least known group of Copepoda in freshwater habitats in Poland, although they are very common and very abundant in the continental waters. The last detailed taxonomic studies of Harpacticoida in Polish inland waters were carried out about 100 years ago. A faunistic and ecological review of 12 harpacticoid species from north-eastern Poland is presented herein for the first time. Two species new to the Polish fauna were recorded: Elaphoidella elaphoides (Chappuis, 1923) and Bryocamptus (Rheocamptus) spinulosus (Borutzky, 1934). Bryocamptus spinulosus is morphologically close to B. zschokkei (Schmeil, 1893). The latter species is considered to be widely distributed in Poland, yet many records of B. zschokkei might in fact refer to B. spinulosus. Distinguishing features of these species were described in detail.

Review of the genus Ommatoiulus in Andalusia, Spain (Diplopoda: Julida) with description of ten new species and notes on a remarkable gonopod struc-ture, the fovea

Zootaxa ◽  
2012 ◽  
Vol 3538 (1) ◽  
pp. 1 ◽  
Author(s):  
NESRINE AKKARI ◽  
HENRIK ENGHOFF
Keyword(s):  
Electron Microscopy ◽  
New Record ◽  
New Records ◽  
Structural Complexity ◽  
Distribution Ranges ◽  
Wide Range ◽  
Comprehensive Comparison ◽  
Original Observation ◽  
First Time ◽  
Scanning Electron

A comprehensive revision of the species of the genus Ommatoiulus in Andalusia, southern Spain, is carried out for thefirst time, revealing the presence of a total of 19 species, among which are one new record for the country, one for con-tinental Spain, two new records for Andalusia and 10 species new to science: Ommatoiulus baenai, O. baileyi, O. hoff-mani, O. jaenensis, O. kimei, O. pseudoflagellatus, O. recueroi, O. reipi, O. sabinarensis, O. schubarti n.spp. Thefollowing taxa are synonymised: Schizophyllum hoplites Verhoeff, 1910, S. diplurum appendiculatum Brolemann,1925, and Ommatoiulus diplurus mauriesi Hoffman, 1975, are regarded as junior synonyms of Ommatoiulus diplurus(Attems, 1903), n.syn. Schizophyllum dorsovittatum estrellanum Verhoeff, 1910, and S. calatravanum Brolemann,1920, are junior synonyms of Ommatoiulus dorsovittatus (Verhoeff, 1893), n.syn. Schizophyllum nivale Schubart,1959, is a junior synonym of Omnmatoiulus ilicis (Brölemann, 1896), n.syn. Full descriptions and diagnostic notes areprovided for all the species with accounts on their distributions, habitats, and notes discussing their taxonomy. A di-chotomous identification key, based on gonopod structures, is presented to facilitate species identification. In the dis-cussion section, the general patterns of species distribution are underlined, showing a clear tendency to ‘endemism’ forthe majority of species and to polymorphism for species with broader distribution ranges, especially O. diplurus. A dis-junct distribution Andalusia/Pyrenees is registered for O. ilicis. A comprehensive comparison of gonopods is attempt-ed, and three main types of gonopod configuration are delimited, denoting a wide range of structural complexity. Thefovea, a cavity in the posterior gonopods, is explored for the first time with scanning electron microscopy, revealing anagglutination of spermatozoa and confirming Verhoeff’s original observation dating back nearly 120 years. The con-stancy of the fovea in all Schizophyllini, combined with its absence in the rest of the julids, provides an additional apomorphy for the tribe.

scholarly journals Pollen Morphology of Some Species of the Genus Sansevieria Petagna (Asparagaceae)

2017 ◽  
Vol 59 (2) ◽  
pp. 63-75 ◽  
Author(s):  
Małgorzata Klimko ◽  
Renata Nowińska ◽  
Paul Wilkin ◽  
Justyna Wiland-Szymańska
Keyword(s):  
Electron Microscopy ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Grain Morphology ◽  
Pollen Grain ◽  
Prolate Spheroidal ◽  
Pollen Grain Morphology ◽  
First Time ◽  
Scanning Electron ◽  
Eleven Species

AbstractPollen grains of 15 species of the genus Sansevieria were examined using light and scanning electron microscopy. The pollen grains were single, but dyads were also found. The basic shape of the pollen grains (with chemical treatment) was subprolate, prolate and prolate-spheroidal and the pollen grains were large (> 50 mm). The pollen grains observed in SEM were prolate-spheroidal, subprolate, prolate and perprolate. The aperture occupied nearly the entire distal hemisphere. The surface of non-apertural areas was microreticulate, psilate-perforate, fossulate and verrucate. The surface of the apertural area was psilate-perforate-verrucate, microreticulate-verrucategemmate and psilate-perforate. The tectum was homogeneous, with perforations. Our results suggest that some species cannot be separated based on pollen grain morphology, but only may be categorized into their groups. The present study investigated pollen grain morphology in eleven species for the first time in terms of pollen micromorphology and provided some important new data.

Ultrasound promoted preparation of Mn(III)-porphyrin nanoparticles: An efficient heterogeneous catalyst for oxidation of alkenes, alkanes and sulfides

2015 ◽  
Vol 19 (12) ◽  
pp. 1232-1237 ◽  
Author(s):  
Saeed Rayati ◽  
Fatemeh Nejabat ◽  
Nasireh Naghashian
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Heterogeneous Catalyst ◽  
Selective Oxidation ◽  
Ultrasonic Irradiation ◽  
Oxidation Of Sulfides ◽  
Wide Range ◽  
First Time ◽  
Scanning Electron ◽  
Efficient Heterogeneous Catalyst

In the present research meso-tetrakis(4-carboxyphenyl)porphyrinatomanganese(III) acetate (Mn(TCPP)OAc) nanoparticles have been prepared for the first time without any stabilizing agent or supporting matrix under ultrasonic irradiation. Scanning electron microscopy (SEM) was used to characterize and investigate the nanocatalyst. Rapid, efficient, facile and highly selective oxidation of a wide range of olefins by tetra-[Formula: see text]-butylammonium hydrogen monopersulfate over the prepared manganese nanocatalyst was investigated. Also oxidation of sulfides and alkanes in the presence of the (Mn(TCPP)OAc) nanoparticles were studied. The catalyst is recovered by filtration and reused at least five times.

Tropical Australian freshwater fungi. V.* Bombardia sp., Jahnula australiensis sp. nov., Savoryella aquatica sp. nov. and S. lignicola sp. nov.

1993 ◽  
Vol 6 (2) ◽  
pp. 161 ◽  
Author(s):  
KD Hyde
Keyword(s):  
Freshwater Fungi ◽  
Freshwater Habitats ◽  
Australian Freshwater ◽  
First Time

Four aquatic ascomycetes are reported from freshwater habitats in Australia for the first time. Three taxa: Bombardia sp., Jahnula australiensis sp. nov., and Savoryella aquatica sp. nov, are illustrated with interference contrast light micrographs. The new fungi are described and their taxonomic placement discussed.* Part IV, Aust. Syst. Bot. 1992, 5, 407–14.

The inland waters of the Outer Hebrides

1979 ◽  
Vol 77 ◽  
pp. 329-351 ◽  
Author(s):  
A. R. Waterston ◽  
A. V. Holden ◽  
R. N. Campbell ◽  
P. S. Maitland
Keyword(s):  
Aquatic Vegetation ◽  
Sea Water ◽  
Inland Waters ◽  
Freshwater Species ◽  
Wide Range ◽  
Outer Hebrides ◽  
Freshwater Habitats ◽  
The Rich ◽  
Aqueous Conditions ◽  
Standing Waters

SynopsisThe Outer Hebrides comprise approximately 1·3% of the land area but 15·8% of the area of standing waters of Great Britain. Streams there are generally small and only three are as large as fifth order. The majority of the lochs occur below 200 m altitude and are less than 25 ha in area. A total of 1375 stream systems enter the sea, and drain the land mass through 9240 stream segments. There are just over 6000 lochs, of which less than half are connected to these networks. Most of the water systems are on geologically base-poor rock or soil, and less than 3%, situated on machair, are base-rich and eutrophic. The islands, due to their situation, receive precipitation in the form of very dilute sea water (with some non-marine sulphate probably derived from fossil fuel combustion) and this leads to unusual concentrations of chloride in the inland waters. Metamorphic rocks are resistant to weathering, so there is usually little variation in the composition of fresh waters except in the machair areas, where calcareous sands affect calcium concentrations and alkalinities.The flora and fauna reflect the aqueous conditions and there are some unique successions of species from high to low salinities even in the same water body. The lochs provide a wide range of habitats for aquatic vegetation, ranging from the rich machair lochs to the oligotrophic peaty lochs (which show marked similarities with their counterparts on the mainland). Three broad categories can be delineated on the basis of their water quality and vegetation: brackish lochs with varying degrees of marine influence, calcareous machair lochs which may also be affected by sea connections, and the peaty lochans of low alkalinity. A few brackish water animals are sufficiently euryhaline to exist in the machair lochs, which are otherwise dominated by freshwater species. The occurrence of chloride in inland waters enables some crustaceans, e.g. Neomysis integer, Gammarus duebeni and Diaptomus wierzejskii to extend into what are poor freshwater habitats. The main constituents of the freshwater fauna are molluscs and arthropods, and a few species of euryhaline fishes, i.e. salmon, sea and brown trout, three-spined and ten-spined sticklebacks and eels. There are some populations of non-migratory charr. No amphibians are present.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Recent Progress and Plans in Computer-Controlled High Resolution Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 154-155
Author(s):  
W.J. de Ruijter ◽  
Peter Rez ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Digital Processing ◽  
High Resolution Electron Microscopy ◽  
Objective Lens ◽  
Linear Filter ◽  
Contrast Transfer Function ◽  
Image Displacement ◽  
Spatially Resolved ◽  
Wide Range ◽  
On Line

Digital computers are becoming widely recognized as standard accessories for electron microscopy. Due to instrumental innovations the emphasis in digital processing is shifting from off-line manipulation of electron micrographs to on-line image acquisition, analysis and microscope control. An on-line computer leads to better utilization of the instrument and, moreover, the flexibility of software control creates the possibility of a wide range of novel experiments, for example, based on temporal and spatially resolved acquisition of images or microdiffraction patterns. The instrumental resolution in electron microscopy is often restricted by a combination of specimen movement, radiation damage and improper microscope adjustment (where the settings of focus, objective lens stigmatism and especially beam alignment are most critical). We are investigating the possibility of proper microscope alignment based on computer induced tilt of the electron beam. Image details corresponding to specimen spacings larger than ∼20Å are produced mainly through amplitude contrast; an analysis based on geometric optics indicates that beam tilt causes a simple image displacement. Higher resolution detail is characterized by wave propagation through the optical system of the microscope and we find that beam tilt results in a dispersive image displacement, i.e. the displacement varies with spacing. This approach is valid for weak phase objects (such as amorphous thin films), where transfer is simply described by a linear filter (phase contrast transfer function) and for crystalline materials, where imaging is described in terms of dynamical scattering and non-linear imaging theory. In both cases beam tilt introduces image artefacts.

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