ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your search history is empty.
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Elsevier  (40,801)
  • American Association for the Advancement of Science  (5,620)
  • Blackwell Publishing Ltd  (3,947)
  • Oxford University Press  (3,715)
  • International Union of Crystallography  (2,113)
  • Annual Reviews
  • 2020-2024  (2,594)
  • 1980-1984  (50,846)
  • 1930-1934
  • 1925-1929  (3,593)
  • 2020  (2,594)
  • 1981  (50,846)
  • 1927  (3,593)
Collection
Publisher
Years
Year
  • 1
    Publication Date: 2023-03-13
    Description: The productive but highly exposed coastline of the southern Benguela eastern boundary upwelling system offers limited natural environment for aquaculture. Saldanha Bay located on the west coast of South Africa is one of the few embayments on the coastline that provides a productive and relatively sheltered environment suitable for the cultivation of shellfish. Consequently, bivalve culture in South Africa is centered in Saldanha Bay and is presently targeted for expansion. Pseudo-nitzschia blooms including toxin-producing species are shown to contribute significantly to the phytoplankton of Saldanha Bay specifically in spring and summer. Their dominance at this time of the year, when upwelling is strongest, fits the ecological profile of Pseudo-nitzschia occurring during periods of high turbulence and nutrients. Multiple Pseudo-nitzschia blooms were sampled under varying environmental conditions and the strength of the relationship between Pseudo-nitzschia cell abundance and particulate domoic acid (pDA) content, reflecting bloom toxicity, varied greatly. This variability is the result of the combined influence of species and strain composition of the Pseudo-nitzschia assemblage and the effect of environmental conditions on toxin production. Elevated levels of pDA were associated with higher concentrations of cells of the P. seriata complex differentiated by frustule width (〉3 µm). P. australis was identified as a toxin-producing species and a prominent member of the P. seriata complex. Low DA levels in shellfish in Saldanha Bay are considered a function of low cellular domoic acid (cDA). Silicate limitation has emerged as an important factor inducing DA production in Pseudo-nitzschia species. The high ratio of silicate to nitrate in Saldanha Bay provides a plausible explanation for the low toxin content of Pseudo-nitzschia blooms in the bay and the consequent low risk posed by these blooms to the aquaculture sector.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2023-10-25
    Description: Ship traffic, population, infrastructure development, and mining activities are expected to increase in the Arctic due to its rising temperatures. This is expected to produce a major impact on aerosol composition. Metals contained in atmospheric particles are powerful markers and can be extremely helpful to gain insights on the different aerosol sources. Thiswork aims at studying the sources of metals in the Arctic aerosol sampled at the Thule High Arctic Atmospheric Observatory (THAAO; Greenland, 76.5°N 68.8°W). Due to the particular composition of Greenlandic soils and to properties of other sources, it was possible to find several signatures of natural and anthropogenic aerosols transported from local and long-range regions. Arctic haze (AH) at Thule builds up on long-range transported aerosol mainly from Canada and Nord America. From a chemical standpoint, this aerosol is characterized by a high concentration of sulfate, Pb, As and Cd and by a La/Ce ratio larger than 1. The Ti/Al and Fe/Al ratios in the AH aerosol are lower (Ti/Al = 0.04 w/w; Fe/ Al= 0.79 w/w) than for local aerosol (Ti/Al= 0.07 w/w; Fe/Al = 0.89 w/w). Conversely, aerosol arising from coastal areas of South-West Greenland is characterized by a high concentration of V,Ni, and Cr. These metals, generally considered anthropogenic, arise heremainly fromnatural crustal sources. In some summer samples, however, the V/Ni ratio becomes larger than 3. In particular, cases displaying this characteristic ratio, as also shown by backward trajectories, are associated with sporadic transport to Thule of ship aerosol from ships passing through Baffin Bay and arriving to Thule during summer. Although further measurements are necessary to confirm the discussed results, the analysis carried out in this work on a large number of metals sampled in coastal Greenland aerosol is unprecedented.
    Description: Published
    Description: 140511
    Description: 5A. Ricerche polari e paleoclima
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2023-10-25
    Description: Calc-alkaline and alkaline magmatic activity is generally separated in space and/or in time. The Eastern Transylvanian Basin in Romania is one of the few places where, during Pleistocene, alkaline eruptions occurred contemporaneously with the calc-alkaline activity. Mantle xenoliths entrained in Perşani Mts. alkaline volcanic products have been studied in order to investigate the interaction of metasomatic agents of different magmatic affinities with the mantle wedge. Based on mineral major and trace element and noble gases in fluid inclusions, two main events have been recognized. The first was a pervasive, complete re-fertilization of a previously depleted mantle by a calc-alkaline subduction-related melt, causing the formation of very fertile, amphibole-bearing lithotypes. This is shown by the a) increased amounts of modal clinopyroxene up to 21.9 % with Al2O3 contents up to 8.16 wt%, higher than what is expected for clinopyroxene in Primordial Mantle; b) 4He/40Ar* ratios up to 1.2, within the reported range for mantle production; c) 3He/4He in olivine, opx and cpx of 5.8 ± 0.2 Ra, among the most radiogenic values of European mantle, below the typical MORB mantle value (8 ± 1 Ra), reflecting recycling of crustal material in the local lithosphere. The second event is related to later interaction with an alkaline metasomatic agent similar to the host basalts that caused slight LREE enrichment in pyroxenes and disseminated amphiboles and precipitation of vein amphiboles with a composition similar to amphiboles megacrysts also found in the Perşani Mts. volcanic deposits. This is highlighted by the 4He/40Ar* and 3He/4He values found in some opx and cpx, up to 2.5 and 6.6 Ra, respectively, more typical of magmatic fluids.
    Description: Published
    Description: 105516
    Description: 1T. Struttura della Terra
    Description: 1V. Storia eruttiva
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Keywords: Mantle refertilisation ; Eastern Transylvanian Basin ; Noble gases ; Post-collisional ; Subduction-related metasomatism ; Solid Earth ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2023-10-26
    Description: The Present-day (〈1.2 kyr) activity of Stromboli (Aeolian Islands, Southern Italy) is fed by a vertically-extended mush column with an open-conduit configuration. The eruptive products are the result of periodic supply of mafic magma (low porphyritic or Lp-magma) from depth into a homogeneous shallow reservoir (highly porphyritic or Hp-magma). Clinopyroxene phenocrysts from the 2003–2017 activity exhibit marked diopside-augite heterogeneities caused by continuous Lp-Hp magma mixing and antecryst recycling. Diopsidic bands record Lp-recharge injected into the shallow Hp-reservoir, whereas resorbed diopsidic cores testify to the continuous disruption and cannibalism of relic antecrysts from the mush. The transition between diopside (∼1175 °C) and augite (∼1130 °C) takes place at comparable P (∼190 MPa) and H2O (0.5–2.4 wt%) conditions. Short timescales (∼1 year) for diopsidic bands from the 2003 paroxysm document restricted temporal intervals between mafic injection, magma mixing and homogenization in the Hp-reservoir. Longer timescales (∼4–182 years) for diopsidic cores indicate protracted antecryst remobilization times. By comparing clinopyroxenes from the Present-day and Post-Pizzo eruptions, we argue a distinct phase in the life of Stromboli volcano is evident from the 2003 paroxysm onwards. More efficient mechanisms of mush disruption and cannibalism involve diopsidic antecrysts remobilized and transported by Lp-magmas permeating the mush, in concert with gravitational instability of the solidification front and melt migration within the shallow Hp-reservoir. Magmatic injections feeding the persistent Present-day activity are more intensively mixed and homogenized prior to eruption, reflecting small recharge volumes and/or a more mafic system in which the mafic inputs are less pronounced.
    Description: Published
    Description: 105440
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2023-10-26
    Description: In active volcanic zones, fault dynamics is considerably fast but it is often difficult to separate the pattern of nearly continuous large-scale volcanic processes (inflation/deflation processes, flank instability) from impulsive episodes such as dyke intrusions or coseismic fault displacements. At Etna, multidisciplinary studies on active faults whose activity does not strictly depend on volcanic processes, are relatively few. Here we present the case-study of the San Leonardello fault, an active structure located in the eastern flank of Mt. Etna characterised by a well-known seismic history. This fault saw renewed activity in May 2009, when pre-seismic creeping along the southern segment preceded an MW 4.0 earthquake in the northern segment, followed by some twenty-five aftershocks. Later, in March–April 2016, creep events reactivated the southern section of the same fault. Both the seismic and aseismic phenomena were recorded by the seismic and GNSS networks of INGV-Osservatorio Etneo, and produced surface faulting that left a footprint in the pattern of ground deformation detected by the InSAR measurements. We demonstrate that the integration of multidisciplinary data collected for volcano surveillance may shed light on different aspects of fault dynamics, and allow understanding how coseismic slip and creep alternate in space and time along the strike. Moreover, we use findings from our independent datasets to propose a conceptual model of the San Leonardello fault, taking into account behaviour and previous constraints from fault-based seismic hazard analyses. Although the faulting mechanisms described here occur at a very small scale compared with those of a purely tectonic setting, this case-study may represent a perfect natural lab for improving knowledge of seismogenic processes, also in other fault zones characterised by stick slip vs. stablesliding fault behaviour.
    Description: Published
    Description: 228554
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Fault ; Earthquake ; Creep ; Seismotectonics ; Behaviour ; Mt. Etna volcano ; 04.07. Tectonophysics ; 04.06. Seismology ; 04.03. Geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2023-10-26
    Description: Numerous studies exist on exhumed tectonic mélanges along subduction channels whereas, in accretionary wedge interiors, deformation mechanisms and related fluid circulation in tectonic mélanges are still underexplored. We combine structural and microstructural observations with geochemical (stable and clumped isotopes and isotope composition of noble gases in fluid inclusions of calcite veins) and U-Pb geochronological data to define deformation mechanisms and syn-tectonic fluid circulation within the Mt. Massico intra-wedge tectonic mélange, located in the inner part of the central-southern Apennines accretionary wedge, Italy. This mélange developed by shear deformation at the base of a clastic succession. Deformation was characterized by disruption of the primary bedding, mixing, and deformation of relicts of competent olistoliths and strata within a weak matrix of deformed clayey and marly interbeds. Recurrent cycles of mutually overprinting fracturing/veining and pressure-solution processes generated a block-in-matrix texture. The geochemical signatures of syntectonic calcite veins suggest calcite precipitation in a closed system from warm (108°-147 °C) paleofluids, with δ18O vlaues between þ9‰ and 14‰, such as trapped pore waters after extensive 18O exchange with the local limestone host rock and/or derived by clay dehydration processes at T 〉 120 °C. The 3He/4He ratios in fluid inclusions are lower than 0.1 Ra, indicating that He was exclusively sourced from the crust. We conclude that: (1) intraformational rheological contrasts, inherited trapped fluids, and low-permeability barriers such as marlyshaly matrix, can promote the generation of intra-wedge tectonic mélanges and the development of transient fluid overpressure; (2) clay-rich tectonic mélanges, developed along intra-wedge décollement layers, may generate low-permeability barriers hindering the fluid redistribution within accretionary wedges.
    Description: Published
    Description: 104086
    Description: 1T. Struttura della Terra
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Tectonic mélange ; Fluid-rock interaction ; Stable and clumped isotopes ; Noble gases ; Fold and thrust belt ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2023-10-26
    Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2020. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved
    Description: The application of a physics-based earthquake simulator to Central Italy allowed the compilation of a synthetic seismic catalogue spanning 100 000 yr, containing more than 300 000 M ≥ 4.0 simulated earthquakes, without the limitations that real catalogues suffer in terms of completeness, homogeneity and time duration. The seismogenic model upon which we applied the simulator code was derived from version 3.2.1 of the Database of Individual Seismogenic Sources (DISS; http://diss.rm.ingv.it/diss/), selecting, and modifying where appropriate, all the fault systems that are recognized in the portion of Central Italy considered in this study, with a total of 54 faults. Besides tectonic stress loading and static stress transfer as in the previous versions, the physical model on which the latest version of our simulation algorithm is based also includes the Rate and State constitutive law that helps to reproduce Omori’s law. One further improvement in our code was also the introduction of trapezoidalshaped faults that perform better than known faults. The resulting synthetic seismic catalogue exhibits typical magnitude, space and time features which are comparable to those in real observations. These features include the total seismic moment rate, the earthquake magnitude distribution, and the short- and medium-term earthquake clustering. A typical aspect of the observed seismicity in Central Italy, aswell as across thewhole Italian landmass and elsewhere, is the occurrence of earthquake sequences characterized by multiple main shocks of similar magnitude. These sequences are different from the usual earthquake clusters and aftershock sequences, since they have at least two main shocks of similar magnitude. Therefore, special attentionwas devoted to verifyingwhether the simulated catalogue includes this notable aspect. For this purpose, we developed a computer code especially for this work to count the number of multiple events contained in a seismic catalogue under a quantitative definition. We found that the last version of the simulator code produces a slightly larger number of multiple events than the previous versions, but not as large as in the real catalogue. A possible reason for this drawback is the lack of components such as pore-pressure changes due to fluid-diffusion in the adopted physical model.
    Description: Published
    Description: 526–542
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2023-07-18
    Description: The 4.5 ka trachytic Plinian eruption of Agnano-Monte Spina is the largest magnitude event of the past 5 ka at Campi Flegrei caldera. The complete eruptive sequence consists of six members, three of which, named A, B and D, are characterized by the association of fallout and pyroclastic density current (PDC) deposits well preserved at proximal locations. In this study, we analyze the textural characteristics of the pumice clasts of the three major fallout deposits (A1, B1, D1) and of their associated PDC deposits (A2, B2, D2), and link them to the physical properties of magma in order to investigate conduit fluid dynamics. A combination of data (field work, grain-size and density measurements, vesicle number densities and size distributions, crystal content, water content) is used to set up the source term conditions for numerical simulations. Each fall/PDC transition is accompanied by distinctive changes in textural properties of the juveniles, recognized by a lowering in vesicle number densities of about one order of magnitude (from 108 to 107 cm−3), indicating a significant decrease in the magma ascent rate. Melt inclusions show a marked decrease in volatile content recurrent at each fall/PDC transition and indicate that the three main pulses of the eruption were fed by distinct and progressively deeper magma batches. Numerical simulations, taking into account magma properties derived from the textural analyses, and variations in initial water content, show decreases in the exit velocities and Mass Discharge Rate (MDR) consistent with such fall/PDC transitions. Different initial water contents together with changes in conduit diameters allow us to simulate the different column heights reconstructed for the three Plinian phases. The reconstructed scenario for the Agnano-Monte Spina eruption involves a stop-start behavior and a top-down trigger for the most voluminous and intense eruptive episode D.
    Description: Published
    Description: 119301
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Campi flegrei ; Plinian eruptions ; Textural analysis ; VSD ; CSD ; Numerical modeling
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2023-10-31
    Description: The terrestrial carbon to nitrogen ratio is a key geochemical parameter that can provide information on the nature of Earth's precursors, accretion/differentiation processes of our planet, as well as on the volatile budget of Earth. In principle, this ratio can be determined from the analysis of volatile elements trapped in mantle-derived rocks like mid-ocean ridge basalts (MORB), corrected for fractional degassing during eruption. However, this correction is critical and previous attempts have adopted different approaches which led to contrasting C/N estimates for the bulk silicate Earth (BSE) (Marty and Zimmermann, 1999; Bergin et al., 2015). Here we consider the analysis of CO2-rich gases worldwide for which a mantle origin has been determined using noble gas isotopes in order to evaluate the C/N ratio of the mantle source regions. These gases experienced little fractionation due to degassing, as indicated by radiogenic ⁎ values (where 4He and 40Ar* are produced by the decay of U+Th, and 40K isotopes, respectively) close to the mantle production/accumulation values. The C/N and ratios of gases investigated here are within the range of values previously observed in oceanic basalts. They point to an elevated mantle C/N ratio (∼350-470, molar) higher than those of potential cosmochemical accretionary endmembers. For example, the BSE C/N and ratios (160-220 and , respectively) are higher than those of CM-CI chondrites but within the range of CV-CO groups. This similarity suggests that the Earth accreted from evolved planetary precursors depleted in volatile and moderately volatile elements. Hence the high composition of the BSE may be an inherited feature rather than the result of terrestrial differentiation. The and ratios of the surface (atmosphere plus crust) and of the mantle cannot be easily linked to any known chondritic composition. However, these compositions are consistent with early sequestration of carbon into the mantle (but not N and noble gases), permitting the establishment of clement temperatures at the surface of our planet.
    Description: Published
    Description: 116574
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2023-10-31
    Description: On the Moon, floor-fractured craters (FFCs) present evidence of horizontal crater-centred magmatic intrusions. Crater floor uplift and moat formation indicate that these sill intrusions occur at shallow depths ( 〈 10 km). While a recent study has demonstrated that magma ascent below FFCs and mare-filled craters was triggered by crater unloading, the mechanism leading to the emplacement of shallow sills is still poorly understood. Here we show that the local stress field due to crater unloading is also responsible for the horizontalisation of the magma flow leading to sill-like intrusions. On Earth, caldera formation has been shown to similarly affect magma trajectories, inducing the formation of a sill-shaped storage zone. Magma ascent to shallow depths below FFCs was however made possible because of a regional tensional stress caused by mare loading on the lunar lithosphere. We show that the tensional stress generated by elastic lithosphere deformation caused by mare loading combined to the local crater stress field can explain the distribution of FFCs on the Moon, with the smallest FFCs being located over a larger distance range from the mare. In particular, FFCs distribution around Oceanus Procellarum is consistent with an average load thickness of ∼ 1 km. This study suggests that magma trajectory in the crust of terrestrial planets can provide a diagnostic of the lithospheric structure and state of stress.
    Description: Published
    Description: 115889
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Publication Date: 2023-11-16
    Description: Lascar (5592 m a.s.l.) and Lastarria (5697 m a.s.l.) are Chilean active stratovolcanoes located in the Central Volcanic Zone (CVZ; 16°S to 28°S) that have developed on top of a 71 km thick continental crust. Independently of the similarities in their Plinian/Vulcanian eruptive styles, their complex magmatic feeding structures and the origins of their magmatic fluids still necessitate constraints in order to improve the reliability of geochemical monitoring. Here we investigate the petrography, bulk-rock chemistry, and mineral chemistry in products from the 1986–1993 explosive eruptive cycle at Lascar and from several Holocene eruptive sequences at Lastarria. These data are integratedwith measurements of the noble gas isotopes in fluid inclusions (FIs) of minerals fromthe same products as well as in fumarole gases. The geochemistry ofminerals and rocks shows that the studied products belong to high-K–calc-alkaline series typical of subduction-related settings, and provide evidence of differentiation,mixing, and crustal assimilation that are higher at Lastarria. The contribution of slab sediments and fluids to magma genesis in thewedge is limited, suggesting a homogeneous mantle beneath CVZ. The deepest crystallization processes occurred at variable levels of the plumbing systems according to the lithostatic equivalent depths estimated with mineral equilibrium geobarometers at Lascar (15–29 km) and Lastarria (~20–40 km). The 40Ar/36Ar and 4He/20Ne ratios in FIs and fumarole gases indicate the presence of some degree of air contamination in the fluids from both volcanoes. The 3He/4He values at Lascar (6.9–7.3 Ra) are relatively homogeneous and comparable to those of fumaroles, suggesting a main zone of magma crystallization and degassing. In contrast, the 3He/4He values at Lastarria (5.31–8.01 Ra) vary over a wide range, suggesting various magma storage levels and providing evidence of crustal contamination, as indicated by the rock chemistry.We argue thatmantle beneath the two volcanoes has a MORB-like signature of 3He/4He, while local crustal contamination explains the lower ratios measured at Lascar.
    Description: Published
    Description: 105615
    Description: 1V. Storia eruttiva
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: Lascar ; Lastarria ; noble gases ; Fluid inclusions ; Crustal contamination ; Mantle wedge ; 04.08. Volcanology ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2023-11-21
    Description: Highlights -He isotopic R/Ra of emitted gas decreases moving away from Albani Hills volcano -Total soil flux of endogenous CO2 at Lavinio-Tor Caldara is estimated to 20 ton/day -Tor Caldara gas has the highest H2S content (up to 6.3 vol.%) of central Italy -Repetition of soil CO2 flux survey shows that flux increases during earthquakes -Gas air concentration monitoring shows that H2S is the killer gas of small animals
    Description: Gas hazard was evaluated at Lavinio-Tor Caldara, the southernmost gas-discharging zone of the quiescent Albani Hills volcano in central Italy. Also this zone, like the other gas discharges of this volcanic complex, is located above a structural high of the buried Mesozoic carbonate basement, which represents the main reservoir for gas rising from depth. All extensional faults affecting the carbonates are leaking pathways along which gas may rise to the surface creating hazardous conditions. Gas is dominated by CO2 (〉90 vol.%) and the second component at Lavinio-Tor Caldara is H2S that displays the highest content (4.0-6.3 vol.%) of all gas manifestations of the Rome region. This H2S enrichment corresponds to a marked decrease in 3He/4He (R/Ra) isotopic ratio suggesting that gas was contaminated in an upper crustal environment. The main gas discharge occurs at the natural reserve of Tor Caldara, in zones where past sulphur mining excavations removed the surficial impervious cover, or along a ditch. Comparison of the results of four soil CO2 flux surveys carried out in 2005-2018 at Miniera Grande within Tor Caldara, indicates that the highest soil CO2 release occurs shortly after local earthquakes. Continuous monitoring of CO2 and H2S air concentration and of wind speed has been carried out for four months in twelve anomalous gas realising sites of Tor Caldara. Results indicate that only H2S reaches lethal concentration (〉250 ppm) near the soil in no wind nights, explaining the presence of small dead animals. At Lavinio, the main soil gas release occurs near old water wells that likely produced a gas blowout during drilling. A total release of over 20 tons/day from 2.93 km2 of gas of endogenous origin, has been estimated for the Lavinio-Tor Caldara area by a detailed soil CO2 flux survey (2,572 measurement points over an area of 3.65 km2). The main structural lineaments of the area have N-S and W-E directions, but also NE-SW and NW-SE directions are well represented. Some sectors of the investigated area are exposed to a severe gas hazard for people and animals and precautionary measures should be adopted.
    Description: Published
    Description: 106985
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: •Lavinio-Tor Caldara, southern periphery of Albani Hills volcano ; •He isotopic R/Ra values ; •Soil CO2 flux surveys ; •CO2 and H2S air concentration monitoring ; •Gas chemistry ; •Gas hazard assessment ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2023-11-14
    Description: The Middle Valle Umbra (central Italy) is a NW-SE 20 km long and 10 km wide Quaternary extensional basin located in the internal sector of the Apennine chain. This area historically experienced strong earthquakes that caused significant damages to the outstanding historical heritage. The same area has been recently hit by the 2016 seismic sequence of Amatrice-Visso-Norcia. With the aim to reconstruct the buried geological structures of the basin, a multi-technique geophysical approach was performed. An extended campaign of ambient noise measurements was carried out to investigate the subsurface setting, and to identify the main geological units. We performed three 2D passive arrays to analyze two different sites within the basin; their aperture was between 150 and 752 m for one site and of 48 m for the other site, to characterize the geological units in terms of sediment thickness and shear-wave velocity profile. Data collected were processed with f-k and MSPAC analysis to extract dispersion curves with good resolution in a frequency range of 0.5–10 Hz and 4.5–18 Hz for the two sites respectively. Spectral ratios were computed for every single station ambient noise measurement performed and for all the stations of the bigger array. Our final target is to extend these results to the whole valley, in order to retrieve the attitude of the main geological units and propose a reliable reconstruction of the subsurface geometry of the basin. Another point of this work is to evaluate the site response in the middle of the valley through the analysis of the earthquakes recorded by the accelerometric station IT.CSA (belonging to the Italian Civil Protection) and the corresponding recordings of the nearby rock station IT.ASS.
    Description: Published
    Description: id 105543
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: site effects ; seismic site characterization ; subsoil model ; spectral ratios ; Valle Umbra ; passive arrays ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2023-11-16
    Description: Submarine methane emissions in the Tuscan Archipelago have been studied since the 1960s, both for economic and research purposes. Offshore gas seepage is mainly concentrated southward and westward of Elba island, along N–S faults related to recent extensional activity in the Tuscan shelf and N–S trending positive magnetic anomalies, which have been interpreted as serpentinites associated with ophiolitic rocks due to their very high magnetic susceptibility. This study focuses on the gas chemistry of a new emission site corresponding to a shallow water mud volcano in the Scoglio d’Affrica area. The Scoglio d’Affrica seep has a gas composition typical of mud volcanoes, with methane as the prevalent component (95 vol%) and minor gases which include carbon dioxide, nitrogen and trace amounts of helium. The combined stable C and H isotope composition of CH4 (δ13C and δ2H) and the enrichment in heavy carbon isotopes of CO2, highlight a prevalent secondary microbial origin for these fluids (δ13C~− 35.8‰ vs VPDB; δ2H~− 166‰ vs VSMOW; δ13CCO2 up to + 21.7‰ vs VPDB). Thus, in spite of the occurrence of positive magnetic anomalies, a possible abiotic origin of methane is excluded. Moreover, the gas from the mud volcano is extremely depleted in 3He and presents typical 3He/4He ratios of a geological setting in which radiogenic crustal helium is strongly predominant. A photo-mosaic of the mud volcano is also reported. A possible connection with other submarine methane emissions in the Tuscan Archipelago is limited to emissions located few kilometers from the Scoglio d’Affrica area. Recent emissions in the area suggest that gases similar in composition from distinct reservoirs, find their way to the surface from Eocene deposits in different time intervals and through different faults and fractures, placed along the Elba-Pianosa ridge.
    Description: Published
    Description: 104722
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Submarine emission ; Mud volcano ; Methane ; Gas geochemistry ; Tyrrhenian sea ; Geochemistry ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2023-11-21
    Description: Trace volatile elements like He are key for understanding the mantle source signature of magmas and to better constrain the relative roles of subduction and crustal processes to the variability of along-arc chemical and isotopic signatures of magmatic fluids. Here we report on noble gas abundances and isotopic data of Fluid Inclusions (FIs) in eruptive products and/or fumarolic gases from the Colombia-Ecuador segment of Andean Northern Volcanic Zone (NVZ). FIs in olivine phenocrysts from Ecuador (El Reventador, Cotopaxi and Tungurahua) yield air-normalized corrected 3He/4He ratios of 7.0–7.4 RA, within the MORB range (8 ± 1 RA). With exception of the Cotopaxi lavas (opx 〈 〈oliv.), these are indistinguishable of those obtained for their cogenetic orthopyroxene pairs and of gas emissions previously reported in literature. Olivine phenocrysts from Nevado del Ruiz fissure lavas also yield the highest 3He/4He (8.5 ± 0.3 RA) for this volcanic system, which is in the range of fumarolic gases for Galeras (previously reported as high as 8.8 RA and here measured to a maximum of 8.3 ± 0.1 RA). Our dataset highlights disparities between isotope signatures of eruptive products from Ecuador (avg. ~7.2 RA) and those reported for the Colombian portion of the NVZ (avg. ~8.5 RA). Previous studies on the geochemistry of erupted products put in evidence significant along-arc variations ascribed either to the involvement of different slab components, or to variable depths of evolution of arc magmas within the continental crust. However, the same variation is not discernible in the signature of noble gases, especially helium, from FIs and gas emissions analyzed in this study, with little inter-variation between Cotopaxi, Reventador and Tungurahua (all within 0.2 RA from the Ecuador average of 7.2) and Galeras and Nevado del Ruiz, whose maximum values differ by ~0.3 RA. We therefore suggest a homogenous MORB-like 3He/4He signature for the mantle wedge beneath this arc segment, whereby along-arc variations in crustal thickness (from 〈35 km at the northernmost part of the segment to ≥50 km at the Ecuadorian arc segment) may factor largely into the variability recorded on our data set. The first CO2/3He ratios obtained in FIs from Andean rocks support the hypothesis of increasing crustal contamination from Colombia to Ecuador, concomitant with increasing crustal thicknesses under the respective arc regions.
    Description: Published
    Description: 119966
    Description: 1V. Storia eruttiva
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Andean Volcanic Belt ; Northern Volcanic Zone ; Fluid inclusions ; Noble gases ; Helium ; Crustal thickness ; 04.08. Volcanology ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2023-11-21
    Description: Azerbaijan hosts the highest density of subaerial mud volcanoes on Earth. The morphologies characterizing these structures vary depending on their geological setting, frequency of eruption, and transport processes during the eruptions. Lokbatan is possibly the most active mud volcano on Earth exhibiting impressive bursting events every ∼5 years. These manifest with impressive gas flares that may reach more than 100 meters in height and the bursting of thousands of m3 of mud breccia resulting in spectacular mud flows that extend for more than 1.5 kilometres. Unlike other active mud volcanoes, to our knowledge Lokbatan never featured any visual evidence of enduring diffuse degassing (e.g., active pools and gryphons) at and near the central crater. Only a very small new-born gryphon was intermittently active in 2019 (with negligible flow). Gas flux measurements completed with a closed-chamber technique reveal extremely low values throughout the structure with average CH4 = 1.36 tonnes yr−1 and CO2 = 11.85 tonnes yr−1. We suggest that after eruptive events, the mud breccia is able to seal the structure preventing gas release and thereby promoting overpressure build-up in the subsurface. This self-sealing mechanism allows a fast recharge of Lokbatan resulting in more frequent and powerful explosive episodes. Our field observations reveal the presence of large (up to ∼50,000 m3) stratified blocks that were originally part of a large crater cone. These blocks were rafted 〉1 km from the vent on top of mud breccia flows. We use a model based on lubrication theory to show that it is reasonable to transport blocks this large and this far provided the underlying mud flow was thick enough and the blocks are large enough. The presence of large rafted blocks is not a unique phenomenon observed at Lokbatan mud volcano and is documented at other large-scale structures both onshore and offshore.
    Description: Published
    Description: 116699
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Lokbatan mud volcano Azerbaijan ; rafted mud breccia megablocks ; gas flux ; self-sealing ; explosive eruptions ; lubrication theory ; Solid Earth ; Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2024-01-31
    Description: The authors regret that the specified units of bioirrigation activity (Ic) and the indices (i.e. IPc,AFDM, IPc,WM, BPc,WM, BPc,AFDM) were incorrect in the original publication. Bioirrigation activity was presented in l/m25 min rather than in l/m2h and the indices were calculated per experimental core rather than per m2. Nevertheless, this does not affect the results and also the conclusions remain unchanged. AICc values for the best models of IPc,AFDM, IPc,WM, BPc,WM, BPc,AFDM have not changed in relation to each other, although they differ in value. The corrected version of Appendix B includes the corrected statistical details (i.e. AICc values). The corrected version of the Fig. 1 is provided below. The authors would like to apologize for any inconvenience caused.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    facet.materialart.
    Unknown
    Elsevier
    In:  EPIC3Current Opinion in Neurobiology, Elsevier, 60, pp. 55-66, ISSN: 0959-4388
    Publication Date: 2024-05-10
    Description: Animal life is rhythmic. Here we provide an overview of various rhythmic behaviors, connected environmental factors and endogenous mechanisms. We not only cover terrestrial species, but also highlight aquatic environments with typically complex interconnected rhythms. We further address diel, seasonal and potential lunar rhythms of humans. While we cannot be complete, we aim to emphasize three aspects: First, to raise awareness for the all-encompassing presence of behavioral rhythms and their importance in ecology and evolution. Second, to raise awareness how limited our mechanistic understanding is, besides analyses in a small set of model species. Finally, we discuss how anthropogenic effects can affect behavioral rhythmicity and how this might affect ecosystems in the future, as ‘For the times they are a-changin'’.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: The development of an automated photographic measuring system (APM) is described. A very accurate laser beam scanning microdensitometer is used to digitise the photographic plate and a series of on line computers analyses the data during scanning. The system is available as a national facility for United Kingdom astronomers and guest investigators.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn décrit un systéme automatisé de saisie de données sur cliché. Un microdensitométre à laser numérise la plaque photographique et les données sont analysées en temps réel par ordinateur. Le systeme est destiné aux astronomes du Royaume Uni et aux chercheurs y séjournant.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungBeschreibung eines automatisierten photographischen Messsystems (APM). Ein hochgenaues Laser-Mikrodensitometer wird dabei zur Digitalisierung der Bilder benutzt, undeine Serie von On-line-Rechnern analysiert die Daten während der Abtastung. Das System steht für Astronomen im Vereinigten Königreich und anderen Forschern zur Verfügung.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Two complementary measuring instruments are described which use a very simple principle and which take three dimensional measurements or plots directly from small objects. The first instrument can achieve accuracies of ± 0·3 mm on objects whose largest dimension is 300 mm. The second can achieve ± 0·02 mm on objects smaller than a 25 mm cube.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn présente deux instruments de mesure complémentaires el de principe très simple permettant de relever dans l'espace des coordonnées sur de petits objets, le premier avec une exactitude de ± 0.3 mm sur des objets de dimension inférieure à 300 mm, le second avec une exactitude de ± 0.02 mm sur des objets de dimension inférieure à 25 mm.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungBeschreibung von zwei Zusatzmessgeräten, die auf einem sehr einfachen Prinzip beruhen und mit denen dreidimensionale Messungen oder Auswertungen von kleinen Objekten direkt durchgeführt werden konnen. Mil dem ersten Gerät kann eine Genauigkeit von ± 0,3 mm bei maximalen Objekt abmessungen von 300 mm und mit dem zweiten von ± 0,02 mm bein Objekten, die kleiner als ein 25 mm-Kubus sind, erreicht werden.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: This paper outlines the technical procedures used in commercial orthophotomap production and attempts to identify some of the main differences in technical approach between orthophotomapping and conventional line mapping.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn décrit les techniques industrielles de production d'orthophotocartes et on compare leur emploi avec celui des techniques classiques.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungSkizzierung der Technologien, die bei der kommerziellen Herstellung von Orthofotokarten angewendet werden, wobei versucht wird, die hauptsächlichen Unterschiede der Techniken zur Herstellung von Orthofotokarten und konventionellen Strichkarten aufzudecken.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: This paper investigates the effect of the deviation of measured points from the standard locations when carrying out a relative orientation of a stereomodel. The analytical solution of more than 100 cases was considered and, for each case, the weights for the elements of relative orientation and the correlation coefficients were evaluated. The stability of the solution was studied by calculating the characteristic roots of the matrix of normal equations.It is shown that, theoretically, the solution of the relative orientation problem can always be achieved whenever the locations of the measured points satisfy stated geometrical requirements. However, the reliability of the solution depends on their exact positions in the stereomodel. When the accuracy is too low, in practice there is no solution.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn étudié l'effet sur l'orientation relative d'un couple de variations de position des points de base. Plus de 100 cas ont été considérés et à chaque fois ont été estimées les précisions des paramètres calculés ainsi que leur correlation. On a de plus, étudié la stabilité de la solution par l'intermédiaire des valeurs propres de la matrice normale.Il n'est pas indispensable, en principe, d'imposer de contraintes précises au choix des points de base; mais de ce choix dépend la fiabilité de la solution, faible s‘il est par trop fantaisiste.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungIn der Arbeit wird der Einfluss der Abweichung der gemessenen Punkte von ihrer Standardlage bei relativer Orientierung eines Stereomodells untersucht. Dazu werden mehr als 100 analytische Lösungen analysiert und für jeden Fall die Gewichte der Elemente der relativen Orientierung und die Korrelationskoeffizienten berechnet. Die Stabilität der Lösung wurde durch Berechnung der charakteristischen Wurzeln der Matrix der Normalgleichungen abgeschätzt.Es wird gezeigt, dass theoretisch immer die Lösung des Problems der relativen Orientierung erreicht werden kann, sobald die Lage der Messpunkte die geometrischen Anforderungen erfüllt. Die Zuverlässigkeit der Lösung hängt jedoch von der exakten Lage der Punkte ab. Wenn ihre Genauigkeit zu gering ist, gibt es praktisch keine Lösung.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: An automatic plotting instrument development is described where the coordinate corrections are introduced in the optical system and not at the photograph. It is suggested that the opto-mechanical devices used for correction and the proposed use of microprocessors for control of these devices offer the possibility of producing a low cost automatic plotter and stereocomparator.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn decrit une solution au probléme de la correction des coordonnées cliché pour le restituteur analytique et le stéréocomparateur: ces corrections sont introduites dans la partie optique du système et commandées par l'intermédiaire de microprocesseurs. Ceci devrait permettre d'abaisser le coût de ce type d'appareil.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungBeschreibung eines automatischen Auswertegerätes, bei dem die Koordinatenkorrekturen nicht den Bildträgern, sondern dem optischen System zugeführt werden. Es wird angenommen, dass die zur Korrektur verwendeten optisch-mechanischen Vorrichtungen und die vorgeschlagene Verwendung von Mikroprozessoren zu deren Steuerung die Möglichkeit zum Bau eines billigen automatischen Auswertegerätes und Stereokomparators bieten.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: The paper deals with the analytical plotter and its impact on numerical photogrammetry. A short introductory section is followed by examples of the use of a Zeiss (Oberkochen) Planicomp C100 in analytical aerial triangulation, close range photogrammetry and the generation of digital height models. The examples demonstrate the suitability of the analytical plotter for numerical photogrammetry. Computer assistance and computer control allow for advanced data acquisition of high accuracy and speed. In addition, the minicomputer controlling the analytical plotter can be used for subsequent data processing. As a result, projects involving numerical photogrammetry can be carried out entirely in-house, without the need of an external computer.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméLe restituteur analytique et la photogrammétrie numérique. On cite des applications du Planicomp C100: aérotriangulation analytique, photogrammétrie à courte distance, constitution de modéles numériques de terrain. Efficacité, rendement, haute exactitude, tels sont les avantages du restituteur analytique. On peut d'autre part bénéficier de l'ordinateur pour toutes sortes de traitements ultérieurs.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungDer Beitrag beschäftigt sich mit dem Analytischen Plotter (AP) und seiner Auswirkung auf die Numerische Photogrammetrie. Nach einem kurzen Einführungsteil wird über den Einsatz eines Zeiss (Oberkochen) Planicomp C100 in der Analytischen Aerotriangulation, in der Nahbereichsphotogrammetrie und beim A ufbau Digitaler Höhenmodelle berichtet. Die Beispiele veranschaulichen die Eignung des AP für die numerische Photogrammetrie. Einerseits erlauben Rechnerstützung und Rechnersteuerung eine allgemeine, genaue und schnelle Datengewinnung. Darüberhinaus aber ermöglicht der, für die Steuerung des AP verfügbare Minicomputer die rechnerische Weiterverarbeitung der Messdaten. Auf diese Weise können numerisch-photogrammetrische Projekte ohne Einsatz eines externen Computers vollständig bearbeitet werden.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Book Reviewed in this article:SPHERE, SPHEROID AND PROJECTIONS FOR SURVEYORS. By J. E. Jackson.REMOTE SENSING IN ARCHAEOLOGY, CULTURAL RESOURCES TREATMENT AND ANTHROPOLOGY: THE UNITED STATES OF AMERICA IN 1979. By J. I. Ebert and T. R. Lyons.A HISTORY OF ARCHAEOLOGICAL AIR PHOTOGRAPHY IN GREAT BRITAIN. By R. R. Downey.PROCEEDINGS OF THE INDUSTRIAL AND ENGINEERING SURVEY CONFERENCE, LONDON, 1980. Edited by M. A. R. Cooper.ANALYSIS AND ADJUSTMENT OF SURVEY MEASUREMENTS. By E. M. Mikhail and G. Gracie.A HISTORY OF THE ORDNANCE SURVEY. Edited by W. A. Seymour.IN FOCUS: a rated guide to the best in photographic equipment. By J. Holtz.MAPS AND SURVEYS OF MALAWI. By C. G. C. Martin and other contributors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: When a member is thought to be domiciled or employed abroad, the name of the country has been added. Errors and omissions should be notified to the Honorary Secretary.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: A brief review of work on airborne metric camera movement has been made. The tolerances for permissible image movement set by various investigators are discussed.The biggest single fault with most metric camera mountings in current use is that the centre of gravity of the camera is well above the line of action of the resilient elastic restoring forces. This results in coupling between the linear vibration of the airframe and the angular motion of the camera. There is a need for a simple device which can be attached to a survey camera in order to record angular motion during actual survey missions.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméAprès une brève revue des travaux concernant les mouvements d'une chambre de prise de vue en vol, on discute les tolérances couramment admises pour ces mouvements.Le défaut de montage le plus fréquemment rencontré, est que le centre de gravité de la chambre est au-dessus de la ligne d'équilibre des forces agissantes.D'où un couplage entre la vibration longitudinale du porte-chambre et le mouvement angulaire de la chambre. Il faudrait créer un dispositif simple permettant d'enregistrer ce mouvement pendant les vols.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungEs wird ein kurzer Überblick über die Arbeiten zur Bewegung von Luftbildmesskammern gegeben. Die von verschiedenen Autoren für die zulässige Bildwanderung angegebenen Toleranzen werden diskutiert. Der schwerwiegendste Fehler, der am meisten bei den gegenwärtig verwendeten Messkammern auftritt, ist der, dass der Kammerschwerpunkt über der Wirkungslinie der schwingungsdämpfenden Kräfte liegt. Daraus resultiert eine Paarung der linearen Vibration mit der Winkelbewegung der Kammer. Es besteht Bedarf für eine einfache Vorrichtung, die an einer Messkammer befestigt werden kann, um die Winkelbewegungen während des Bildflugs aufzuzeichnen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Micronuclear mitosis in living Spirostomum teres has been studied by sensitive polarization microscopy, and the dynamic aspects of micronuclear division are described. The small, spherical, interphase micronuclei lie in form-fitting depressions in the macronuclear surface. Nuclear division begins with the rounding and slight swelling of the macronucleus and, coincidentally, the micronuclei move out of the depressions and away from the macronucleus, increase in size, and become weakly birefringent. As mitosis proceeds, the micronuclei increase in uniaxial birefringence and elongate to form irregular ovoids that convert to angular structures displaying principal axes of positive birefringence so divergent as to appear oriented at a right angle to one another. Micronuclei maintain this appearance for as long as 60 min and then abruptly change to rectangular-shaped structures, increase in uniaxial birefringence, and begin anaphase elongation. The somewhat dumbbell-shaped micronuclei lengthen at the constant rate of 2.0 μm/min to reach lengths 〉70 μm. It appears that little half-spindle shortening occurs during spindle elongation. Accompanying the changes in micronuclear spindle length are changes in birefringence. Just before elongation begins, presumably metaphase, the micronucleus is uniformly and intensely birefringent. At the magnifications employed, a chromosome plate is not clearly visible as a region of reduced birefringence. As elongation begins, the putative half-spindles are more birefringent than is the interzone, a condition that is maintained until the spindles have achieved ∼30% elongation, at which time a region of increased birefringence develops at the center of the interzone. This pattern persists for a very short time, then gives way to a uniform birefringence of the entire separation spindle that is maintained until elongation is completed. The rate of micronuclear spindle elongation, changes in micronuclear dimensions, and corresponding changes in birefringence are discussed with respect to possible mechanisms of mitosis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Studies performed with the basidiomycete Laccaria trullisata collected from the sandy beach at the Hempstead Lake State Park, Long Island, New York, during the growing seasons of 1979 and 1980, have demonstrated a carposphere (equivalent to rhizosphere) effect. This region exerts a positive influence on the population density of amoebae when numbers are compared with those obtained in the bare sand 5 cm away. Moreover, amoebae have been shown to exist in, and have been recovered from, internal tissue of the cap (72%) and stalk (91%) of these mushrooms. A partial characterization of three strains of amoebae isolated from the internal tissue of L. trullisata and established in clonal culture is presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: L'étude, par le protargol, des phénomènes infraciliaires et de leur corrélation avec les phénomènes nucléaires au cours de l'autogamie dans le genre Euplotes montre, par comparaison avec la conjugaison, que les diverses étapes de la morphogenèse sont liées à la progression de l'état nucléaire. Par ailleurs, l'étude comparative des différents types de morphogenèse (bipartition, phénomena sexuel, réorganisation induite par le jeǔne) permet de supposer qu'il existe deux territoires morphogènes soumis à des systèmes de régulation bien distincts. La comparaison des séquences de morphogenèse chez divers hypotriches conduit à dresser un plan général d'évolution de la régulation de l'activité corticale en relation avec l'étendue des remaniements associés à la stomatogenèse.〈section xml:id="abs1-2"〉〈title type="main"〉ABSTRACTThe changes in the arrangement of the infraciliature associated with autogamy in Euplotes are described and compared with similar events associated with conjugation. The successive steps of morphogenesis are strongly correlated with nuclear processes. The comparative study of different types of morphogenesis (binary fission, sexual phenomena, starvation-induced reorganization) leads to the hypothesis that two morphogenetic fields (a ventral one and a dorsal one) depend on separate regulatory systems. From the viewpoint of evolution, the morphogenetic sequences of some hypotrichs have been compared. A general scheme of the evolution of cortical regulation is proposed, taking into account the extension of the area concerned with stomatogenic activity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mouse omentum was studied after intraperitoneal challenge with tachyzoites of Toxoplasma gondii. Parasites inhabit omental histiocytes, fibroblasts, mesothelial cells, and free peritoneal macrophages. Recently infected cells showed enhanced metabolic and functional activity. Villous projections of the parasitophorous vacuole wall appeared, usually opposite the anterior pole of the parasite. In mesothelial cells, projections formed terminal swellings not observed in other infected cells. Activation of host cells was followed by reduction of the density of the cytoplasmic matrix, autophagosome formation, and intracellular edema, indicating the damage. The wall of the parasitophorous vacuole loses the supporting host cell endoplasmic reticulum that was attached to the vacuole just after entrance of the parasite into the cell. Then lysis of the parasitophorous vacuole and complete cell destruction occurs. The growth of parasites in undamaged cells does not coincide with the inflammatory response. Inflammation of the peritoneum develops only after the start of mass destruction of infected cells. Thus tachyzoites of Toxoplasma exert significant pathogenic effects by their ability to activate the host cell, causing lysis of the parasitophorous vacuole and subsequent destruction of the entire cell.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Discophrya collini is a free-living suctorian with retractile tentacles covered by a thick fibrous cortex. The tentacles contain a microtubular central canal surrounded at the base by a fibrous collar. Electrical stimulation induces a reproducible tentacle retraction. With extracellular electrodes, the tentacles nearest the anode respond initially, contracting by up to 75% of their original length. There is an inverse relationship between voltage level and duration of stimulus in producing a threshold response, and at a set voltage, between duration and degree of retraction. With intracellular electrodes, the membrane potential has been measured as -30 mV, and tentacle retraction occurs in response to as little as 1.25 nA when the intracellular electrode is made the cathode of the circuit. SEM studies show that retracted tentacles have a wrinkled cortex, while TEM shows that the microtubular canal bends as it enters the cytoplasm. No consistent changes occur in the microtubule configuration of the canal on retraction, suggesting that the microtubules are not directly involved in the contractile mechanism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A rapid in vitro prescreen for Fe-binding chelators has been developed with growth of Crithidia fasciculata and the sparing of its heme requirement in a defined medium as a test system. The prescreen functions as an index of chelator-mediated Fe transport and as an index of growth inhibition, presumably by the interference with Fe and/or heme metabolism at intracellular chelatable sites. Of 161 chelators examined, 84 were active heme-sparers; 32 of these inhibited growth at low chelator concentrations. Twenty-eight other chelators inhibited growth and another 49 were inactive. Such chelating activity directed at Fe and heme targets in hemoflagellates may provide leads for chemotherapy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Study of microorganism growth kinetics requires measurement of maximal specific growth rate. Standard methods of measurement-batch, semicontinuous and continuous steady state-have sources of imprecision that can be substantially reduced by a modification of the continuous steady-state method. Data are presented, using the ciliate Tetrahymena pyriformis, that indicate that the theoretical foundation of the new method is firm and that precision can be increased.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Viable merozoites of Plasmodium knowlesi were isolated and the proteins that were labeled on intact merozoites by lactoperoxidase-catalyzed radioiodination were identified. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography of Triton soluble extracts of labeled merozoites demonstrated eight major bands ranging in apparent molecular weight from 150,000 D to 22,000 D. Exposure of intact merozoites to trypsin (10 μg/ml) for 10 min resulted in the loss of the two highest molecular weight proteins (150,000 D and 105,000 D) and the appearance of two new bands at 70,000 D and 62,000 D. Trypsin treatment under these conditions also removed the receptor(s) for merozoite attachment to erythrocytes. Therefore, these high molecular weight proteins are candidates for the merozoite component that attaches to erythrocytes. There was no evidence that the labeled membrane components were serum or erythrocyte membrane components, two potential contaminants in the preparation. Anti-rhesus erythrocyte antibody did not precipitate labeled merozoite proteins. Furthermore, the immunoprecipitation of labeled merozoite proteins by rhesus anti-merozoite serum was not inhibited by erythrocyte ghosts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Species of trypanosomatids without endosymbionts (Leptomonas seymouri, L. collosoma, L. samueli, Crithidia fasciculata, C. luciliae, C. acanthocephali, Herpetomonas megaseliae, H. mariadeanei, H. samuelpessoai, H. muscarum muscarum, Trypanosoma cruzi) and species of trypanosomatids with endosymbionts (Crithidia deanei, C. oncopelti, Blastocrithidia culicis) were comparatively studied by means of electron microscopy. Artificially aposymbiotic strains derived from species with symbiont were also included in the survey. Species with symbiont were found to differ in some ultrastructural aspects from the group of species without symbiont. Paraxial rods of flagella or intraflagellar structure were found exclusively in species without symbiont. Peripheral branching of mitochondria, accompanied by absence of subpellicular microtubules in sites where the mitochondrial branches are appressed to the cell membrane, were found exclusively in species with symbiont. Networks of kinetoplast DNA fibrils were found to be larger and looser in species with symbiont. Symbiont-free strains of species with symbiont retained the same morphological characteristics of their parental species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: During a freeze-fracture electron microscopical study of the plasma membrane of Tetrahymena, several different types of organized particle assemblies were observed. Three of these were found only on the protoplasmic face and were localized in the anterior-ventral region of the cell. These consisted of plate-like arrays composed of 4–25 triplet rows of small 3–4 nm particles; long, paired linear arrays localized at the tops of cortical ridges and composed of 7–8 nm particles; and elongated tetragonal arrays located in the grooves between ridges and composed of approximately 10 nm particles. The distribution of these arrays is consistent with roles in cellular morphogenesis, chemoreception, or cell-cell pairing during conjugation. In addition, a unique particle track associated with the cytoproct (anal pore) was observed in the external face of the plasma membrane. Furthermore, the protoplasmic face of the plasma membrane is characterized by a high density of particles organized into localized microarrays, consisting of small paracrystals or strings, which exhibit a loose higher-order patterning most evident toward the anterior end of the cell. Particle distributions on the protoplasmic face do not appear to be significantly altered by conditions that cause clumping of alveolar membrane particles. Taken together, these observations are consistent with the idea that the proteins of the plasma membrane are highly ordered and relatively immobile and that the structure of the plasma membrane is regionally differentiated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . A new species of Dactylosoma (Dactylosomatidae, Piroplasmia), for which the name Dactylosoma hannesi n. sp. is proposed, was discovered in blood erythrocytes of Mugil cephalus, Liza richardsoni, and L. dumerili (Mugilidae) from Swartkops estuary, located east of Port Elizabeth, South Africa. The life cycle of this species differs in some respects from that described for all other known species of Dactylosoma and Babesiosoma. Mature schizonts contain eight nuclei but undergo division only to two to four daughter cells. During cytoplasmic cleavage, schizonts assume triad, rosette, or cruciform shapes. Merozoites are finally produced through a series of binary fissions of these daughter cells which may also be involved in additional nuclear divisions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Electron microscopy was used to examine the flagellar apparatus of Herpetomonas ampelophilae from the gut and malpighian tubules of Drosophila melanogaster. The flagellates attach to the microvilli either by weaving their flagella between the microvilli or by engulfing several microvilli with an external flagellar membrane. The first type predominated in the gut while the second type was limited to the malpighian tubules. Desmosomes were not involved in either type of attachment. A subpellicular collar with emerging microtubules was found to be adjacent to the desmosome of the flagellar pocket of herpetomonads in the gut.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Prorocentrum micans Ehrenberg, a free-living marine dinoflagellate, was used to test the intracellular toxic action of cadmium. The cells were cultivated in Erdschreiber medium, with Cd concentrations of 10–100 ppb. Thin sections of treated cells, examined ultramicroscopically, exhibited vacuolations, increased numbers of lysosomes, and severe mitochondrial damage. The first two alterations are a general response to toxicity; the third is Cd specific. Although some chloroplasts were affected by Cd, they were not very sensitive to its action. The nuclear apparatus was not morphologically affected.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Toxoplasma-like avian parasites inhabiting mononuclear phagocytes have been called Haemogregarina, Toxoplasma. avian Toxoplasma, Atoxoplasma, and Lankesterella by various authors. My attempts to transmit the parasites by bloodsucking mites or by transfer of blood and tissues of infected sparrows and canaries were unsuccessful. However, it was noted that the infection was exacerbated under conditions that favored transmission of coccidiosis: crowding and lack of cleanliness. Oral inoculation of sporulated oocysts of Isospora resulted in death from overwhelming macrophage infection with Toxoplasma-like organisms. Experiments using sparrows and canaries showed that the Isospora species involved was not cross infectious. Further investigations using canaries demonstrated that after oral oocyst inoculation, infection of macrophages spread from the submucosa of the duodenum to the liver. spleen, and lungs. After several generations in the internal organs, asexual multiplication, occured in the intestinal epithelium of the small intestinc. Fecal oocysts first appeared at the end of 9–10 days. Oocysts continued to be passed in the feces for months after infection. This chronicity may be explained by the relatively long life of the macrophages that serve as host cells for the asexual stages as compared to the intestinal epithelium which is the cell type parasitized by conventional coccidia.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Stages of mitosis of the micronuclei of Stentor coeruleus were described as seen by transmission electron microscopy. Cells in division and those regenerating new oral membranelles were studied. Microtubules were found in early prophase in the karyoplasm and interspersed between the condensing chromatin. A monaxial intranuclear spindle is formed by early metaphase, with kinetochore microtubule attachment sites on the chromosomes. The spindle elongates, separating the daughter nuclei at anaphase. A new nuclear envelope, consisting of two unit membranes, begins to form at late anaphase. Small segments of membrane found in the space between the newly forming and the old micronuclear envelopes appear to fuse to form the new nuclear envelope. No ultrastructural differences were found in the mitotic nuclei of cells in division or regeneration.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Strains of Tetrahymena thermophila were examined in an attempt to establish what role certain ions (Na+, K+, Li+, Ba++, Ca++, Mg++, Mn++, Al+++, Fe+++) play in influencing cell survival time in a culture medium. In short-term experiments (20–30 min), cell survival time in a 1% peptone medium is directly related to the valence of the ion employed. Long-term observations (lasting up to five days) in a 1% peptone medium containing lower ion concentrations revealed that the effects on cell-cycle time are not correlated with the valence state of the ion. Comparisons were made among the ionic resistances of strains of T. thermophila, of T. pyriformis sensu stricto, and of two subspecies of T. pigmentosa. Strains within a species are highly correlated in their patterns of ionic response, while marked differences between species occur. The most distinctive group of strains examined came from one of the subspecies (syngen 6) of T. pigmentosa.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . A two-stage chemostat modified to accommodate the growth of adhesive organisms was used to determine the yield constant, Y, of a representative soil amoeba, Acanthamoeba polyphaga, utilizing as its prey Pseudomonas paucimobilis. The first stage consisted of a glucose-limited bacterial culture in steady state. The second stage consisted of a simplified predator-prey system, nongrowing bacteria serving as the limiting substrate for amoebae. A refined methodology to more accurately determine Y was developed, and Y for Acanthamoeba polyphaga in batch and continuous culture was determined to be 19.1%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The swiftness of thermotaxis of Paramecium caudatum has been investigated for various populations of organisms by measuring the transient spatial distribution of the gathering process of organisms that are transferred to a temperature-gradient cell from the culture medium. The dispersion obtained from the spatial distribution for each population is found to decrease linearly with time and finally reach a steady state value. The gathering rate determined by the slope of the dispersion strongly depends on population; it increases with population.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Blastocystis hominis, an anaerobic intestinal protozoan parasite of man, has a generation time (GT) in axenic culture of 8.5–19.4 h, depending on the strain tested. Average GT of the eight strains was 11.7 h. Zero growth time cell counts of 5.0 × 105/ml to 2.0 × 106/ml rose in 3–5 days to 1 × 107 or 1 × 108 cells/ml. The GT was determined for the 24-h period during which the most rapid growth occurred; about 2% of the B. hominis cells were in division during this time. Division under the culture conditions provided was by binary fission, the usual mode for B. hominis in vitro as well as in vivo. Division times were determined also by direct observation of individual dividing cells in slide cultures. These were usually ca. 40–60 min but sometimes as low as 20 min.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In contrast to the situation in 13 other species of the Tetrahymena pyriformis complex, in which the condensed degenerating old macronucleus lies in the posterior end of the cell during the late stages of conjugation, in Tetrahymena tropicalis that nucleus is found in the anterior portion. This developmental characteristic may be useful for taxonomic purposes as well as being of value in investigations on nucleocytoplasmic interaction.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Eimeria nuttalli oocysts were found in 58% (21/36) and E. procyonis oocysts in 25% (9/36) of raccoons Procyon lotor in Illinois, and sporocysts of Sarcocystis sp. in 17% (2/12) of other raccoons in Illinois. The oocysts of E. nuttalli were ellipsoidal to ovoid. 15–21 × 12–17 μm, with a one-layered, smooth, colorless wall. The oocysts of E. procyonis were 22–28 × 18–22 μm, with a rough, striated, brownish, two-layered wall. The sporulated sporocysts of Sarcocystis sp. were 11–13 × 8–10 μm. Attempts to infect baby pigs by feeding them sporocysts of Sarcocystis sp. from the raccoon failed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Comments are made concerning the work reported at this Conference by Dr. Edith Box. The importance of stress on the animals used in experimental work is emphasized. Difficulties in identification of isosporan species in birds are mentioned.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A trypanosomatid flagellate, Leptomonas sp., develops and multiplies in the macronucleus (only) of natural and laboratory-reared populations of the ciliate Euplotes. Up to 90% of the natural populations of Euplotes in our test pond had such nuclear infections. Laboratory infections were transmitted to this ciliate by feeding it liberated parasites. Paramecium resisted infections. All laboratory-induced infections were lethal to Euplotes, while control clones of the uninfected ciliates remained viable. This leptomonad, unlike Leptomonas karyophilus (found in Paramecium), shows no leishmanial forms in its several ciliate hosts and shows a varied pattern of locomotion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Some generalizations of a decade ago are reexamined in light of modern advances in coccidiology. Perhaps surprisingly, not many modifications need or can yet be made. Future successes of significance will be in areas of immunology and chemical genetics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Stocks of the Tetrahymena pyriformis complex have been collected in North America and their mating reactivity has been studied. In addition to stocks mating with Tetrahymena americanis, T. borealis, T. pigmentosa, T. hyperangularis, and T. australis, stocks belonging to old syngen 5 and three new mating groups, numbers 13, 14, and 15, were discovered. Syngen 5 and groups 13 and 14 are distinct “biological” species, based on their reproductive isolation from other groups and on the ability of withingroup crosses to produce immature progeny. These species have been named T. hegewischi n. sp., T. sonneborni n. sp., and T. nipissingi n. sp., respectively. The cross between the two group 15 stocks did not produce immature progeny, and there is not sufficient evidence to conclude that this pair of stocks represents a separate species. Temperature tolerance measurements have been made on stocks representing all known micronucleate members of “pyriformis” complex. Within each species, the range of temperature tolerances is narrow; the average within-species standard deviation is 0.63°C. The species averages range from 32.7 to 40.7°C. Using syngen numbers, the order from lowest to highest temperature tolerance is 9, 8, 10, 7, 6, 4, 13, 14, 12, 11, 5, 3, 2, 1. The large differences among species make temperature tolerance a useful aid in identification, but the origins of the differences among species are unknown.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Members of the family Sarcocystidae, as defined by Frenkel, have had a complicated history, principally due to the existence of both coccidial and cystic stages. This formerly clandestine relationship resulted in dual or partial designations of nomenclature for individual species. The problem was further compounded by the obligatory heteroxeny of several of the genera, making it impossible to transmit the parasites from one individual to another of a single host. As a result, oocysts similar in appearance, though from hosts separated taxonomically up to the familial level, were sometimes considered to be identical. Discoveries within the last decade have generated much interest and some understanding. Current studies of these and other coccidia should emphasize complete cyclical transmissions with cognizance of potential heteroxeny with the production of tissue cysts in intermediate hosts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Book reviews in this article: Ecology and Parasitology. Alexander, M., ed. 1980. Advances in Microbial Ecology Smith, H. G. 1978. The Distribution and Ecology of Terrestrial Protozoa of Sub-Antarctic and Maritime Antarctic Islands Taylor, Angela E. R. & Muller, R., eds. 1980. Vaccines Against Parasites Kreier, Julius P., ed. 1980. Malaria New Textbook of Protozoology Farmer, John N. 1980. The Protozoa: Introduction to Protozoology Phytoflagellates and Serial Endosymbiosis Theory Cox, Elenor R., ed. Phytoflagellates Tappan, Helen. 1980. The Paleobiology of Plant Protists. Margulis, Lynn. 1981. Symbiosis in Cell Evolution: Life and Its Environment on the Early Earth. Intercellular Communication and Nuclear-Cytoplasmic Interactions O'Day, Danton H. & Horgen, Paul A., eds. 1981. Sexual Interactions in Eukaryotic Microbes Whitson, Gary L., ed. 1980. Nuclear-Cytoplasmic Interactions in the Cell Cycle. Invertebrate Texts Alexander, R. McNeill. 1979. The Invertebrates Barnes, Robert D. 1980. Invertebrate Zoology Engemann, Joseph G. & (the late) Hegner, Robert W. 1981 Invertebrate Zoology ATCC Catalogue of Strains Hatt, Harold D., ed. 1980. The American Type Culture Collection: Catalogue of Strains I.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Polyamines are multiply amine-substituted straight-chain aliphatics; their content in different tissues may vary widely, and their functions are many. Their main routes of biosynthesis originate from ornithine and methionine. Polyamine content and biosynthesis in tryposomatid flagellates are reviewed concluding with emphasis on their possible role as critical drug targets in these parasitic protozoa so pathogenic for man in large areas of the world.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: During spring and autumn, the total number of amoebae and the number of Acanthamoeba species able to grow at 37°C were determined in six thermally polluted factory discharges and the surrounding surface waters. The isolated Acanthamoeba strains were studied for growth in axenic medium, cytopathic effect in Vero cell cultures, and virulence in mice. Although more amoebae were isolated in autumn, the number of Acanthamoeba species was lower than in spring, when the percent of pathogenic strains among the isolates was highest. Higher concentrations of amoebae were found in warm discharges, and more virulent strains occurred in thermal discharges than in surface waters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Eight species of loricate choanoflagellates (Acanthoecidae), Acanthoecopsis spiculifera Norris, Bicosta antennigera Moestrup, Bicosta spinifera Throndsen, Calliacantha multispina Manton & Oates, Calliacantha simplex Manton & Oates, Crinolina aperta Leadbeater, Diaphanoeca multiannulata n. sp., and Parvicorbicula socialis (Meunier) Deflandre, have been observed, by light and electron microscopy, in samples obtained from the Weddell Sea during the austral summer of 1977. Diaphanoeca multiannulata is described for the first time from these samples: the other organisms are discussed. The distribution of most species within the Weddell Sea was widespread. Habitats in which choanoflagellates were found included the water column, the edge of (or ponds on) ice floes, and the interior of ice floes. The distributional, environmental, habitat, and/or morphological range of all previously described species is expanded. Methods of variation of transverse costal diameters between genera may be potentially useful to the understanding of taxonomy and phylogeny of this family.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Allantosoma intestinalis, a suctorian ciliate isolated from the intestine of the horse, was studied utilizing light and electron optical methods. These small sausage-shaped organisms have a varying number of tentacles (between one and 12) located at each extremity of the body. The microtubular axoneme of each tentacle in cross-section consists of two files of microtubules arranged in a daisy-like configuration. Haptocysts occur in the tentacle shaft, abutted to the plasma membrane of the knob of the tentacle, and in the cell body. The haptocysts are bottle-shaped, with prominent annular striations around their midportion. The cell is covered by three membranes, an outer plasma membrane, an outer alveolar, and an inner alveolar membrane. A thin epiplasmic layer is found beneath the inner alveolar membrane, and a single row of microtubules underlies the epiplasm. The subpellicular microtubules are arranged parallel to each other forming a corset around the cell along the long axis: such a system is not characteristic of suctorians. A field of diminutive kinetosomes (each 180 nm long, max. of 15 per field), lacking cilia, was found below the cortex. The function of these prokinetosomes is unknown. A ciliated swarmer has not been observed, only the nonciliated adult. The characteristics of Allantosoma are compared with those of other suctorian genera.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Temperature shifts have been used to block critical points in the conjugation sequence of Paramecium tetraurelia. Increasing temperatures above 27°C reduced ciliary agglutination, pair formation, and nuclear exchange; a complete inhibition of these stages occurred at 37°C. Temperatures below 19°C had no effect on ciliary agglutination or nuclear exchange but completely inhibited pair formation. The bases for the cells’ inability to form pairs at 19°C and 37°C were sought. Cells placed below 19°C were unable to deciliate or fuse membranes in the holdfast region; at 37°C, membrane fusion in both the holdfast and paroral regions was prevented. Time course studies on cross-fertilization reveal that temperatures 35°C block all stages of the process up to the actual exchange of pronuclei. After the exchange has begun, the process continues despite the elevated temperature. Temperature shifts are discussed as a means of conditionally blocking critical points in the developmental program of conjugation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . [14C]chimyl and [3H]batyl alcohols were added to Crithidia fasciculata cultures during the mid-log phase of cell growth, and the lipid extracts of the cells were analyzed for degradation products. C. fasciculata cells were able to take up exogenous glyceryl ethers, and in amounts as high as the endogenous lipid content. The glyceryl ether taken up by the cells was incorporated into lipids either prior to the ether bond cleavage or after degradation to fatty acid. The extent of degradation and the degree of incorporation of degradation products into cellular lipid were higher for chimyl than for batyl alcohol. Batyl alcohol was not metabolized efficiently, leading to the formation of large intracellular pools of free substrate. One product of glyceryl ether degradation was identified as alkyl-dihydroxy acetone, and was detected inside and outside of the cells. The data strongly suggest that this product is the first stable intermediate in the degradation process and indicate that the extracellular formation of alkyl-dihydroxy acetone is due to the action of exocnzyme; ecteted by the cells. The constant detection of alk I cnyl glycerol among the degradation products indicates the existence of a second mechantsm in C. fasciculata for converting the alkyl-to alkenyl-glycerol.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Sick budgerigars from a local aviary were found to be infected with Giardia. The trophozoites were of the Giardia duodenalis type as defined by Filice with elongate median bodies pointed on one or both ends and more or less perpendicular to the long axis of the body. Using three fixation-staining methods, and material from three birds, the length ranged from 10 to 18 μm and the width from 4.5 to 11 μm with a mean length to width ratio of 2. Attempts to culture the trophozoites in vitro from intestinal scrapings were unsuccessful. Also attempts to transmit the infection by fecal cysts to canaries and mice failed. It is proposed that the budgerigar form be called Giardia duodenalis, race psittaci.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Three species of Pseudocohnilembus were examined with respect to infraciliature and the silverline system. The freshwater species P. putrinus and P. pusillus exhibited no differences in general organization of the argyrophilic structures when compared with the marine P. marinus. A review of the Pseudocohnilembus species that have been described on the basis of silver preparations shows that at present four species have been well characterized: P. pusillus (Quennerstedt, 1869) nov. comb., P. putrinus (Kahl, 1928) nov. comb., P. hargisi Evans & Thompson, 1964, and P. marinus Thompson, 1966, P. persalinus Evans & Thompson, 1964 and P. longiseta Evans & Thompson, 1964 are regarded as identical with the older known P. pusillus, because with respect to morphology and argyrophilic structures they are within the range of variability of that species; and their names thus fall as synonyms of P. pusillus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The structure of micronemata arising from the surface of the bloodstream form of Trypanosoma gambiense was studied by electron microscopy. In order to produce micronemata, trypanosomes were incubated in either 1) phosphate buffered saline supplemented with glucose (PBSG), 2) immune mouse serum or 3) PBSG after passage through a DEAE-cellulose column. Electron microscopic examination of the parasite revealed the presence of thread-like micronemata arising from the anterior end and from the flagellar pocket regardless of the incubation conditions. Negative staining revealed a distinct peripheral fringe layer with nodular protrusions covering the entire surface of the micronema. The distribution and number of intramembrane particles (IMP) on the P and E faces of the micronema were similar to those of the flagellum of T. gambiense, indicating a close relationship between the membrane structure of the micronema and the flagellum. Micronemata became fragmented and adhered to each other after incubation of the parasite in the media for 12 h. Since micronemata tend to have the characteristics of adhesiveness and fragmentation, fragments of these structures might adhere to various host organs. Dispersal of potential antigenic material might be responsible, in part, for the induction of the host immune response.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The motion of Paramecium caudatum has been investigated at various temperatures by measuring the transient behavior of spatial distribution in the diffusion process of organisms that, by electric stimulus, are initially gathered at a single place in the glass culture cell. The spatial distribution through the course of diffusion has a nearly Gaussian profile. Dispersion was obtained at 1 sec intervals and increased linearly with time. The time dependence of the dispersion gave a diffusion coefficient for the random motion of the organisms. The results show that the diffusion coefficient has a maximum at the temperature at which the paramecia were cultivated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Conjugating cells of Euplotes vannus (syngens Naples and Barcarès) were investigated for Con A-binding sites by means of fluorescence microscopy. Cells fixed with 0.4% paraformaldehyde and incubated with 15 μg/ml FITC-Con A showed a distinct region of strong fluorescence, the size, shape and localization of which characteristically changed during the course of conjugation, first appearing at courtship stage (cells contact without forming pairs) and vanishing soon after the migration pronuclei have been exchanged, but before cells have separated. Con A binding and conjugation were blocked by cyclohexamide and α-galactosidase. Con A-binding was also inhibited by α-mannosidase, α-glucosidase and β-galactosidase without affecting conjugation except a delay of pair formation. The results suggest an involvement of newly formed or translocated glycoconjugates in cell pairing during conjugation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The development of Sarcocystis cruzi was studied in an 11-day-old calf killed seven days postinoculation with 5 × 108 sporocysts from feces of coyotes. Uninucleate zoites were found in arteries of mesenteric lymph nodes but not in other organs. Zoites measured 4.9 × 3.0 (3.5–7.0 × 2.1–3.5) μm. Of the 36 zoites studied, 31 were in endothelial cells, four were in macrophages in the lumen of arteries, and one was free in the lumen of an artery. Infected endothelial cells were two to three times larger than uninfected cells. Zoites appeared structurally similar to sporozoites. The occurrence of zoites in macrophages suggests that sporozoites of Sarcocystis might use such cells to reach the site of their first merogony.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The enzyme that catalyzes the critical conversion of the proposed reductive thymidine catabolic end product, P-aminoisobutyric acid, to the initial anabolic reutilization substrate, probably methylmalonic semialdehyde, was investigated to un- ambiguously substantiate the operation of a reductive pyrimidine catabolic and reutilization pathway in Tetrahymena pyriformis strain GL. Although most of the studies on the further metabolism of P-aminoisobutyric acid in other organisms suggested transamination of p-aminoisobutyric acid to methylmalonic semialdehyde followed by its further oxidation to methylmalonic acid, such a transaminating system could not be demonstrated. By means of a sensitive fluorometric assay system, however, a low, but significant amount of P-aminoisobutyric acid oxidase activity was detected. This enzymatic activity exhibited the following characteristics in homogenates: good activity in alkaline 0.2 M Tris-HCI buffer with a rather broad pH optimum ranging from 7.8 to 9.0; optimum activity at a temperature of 37°C; stimulation on the addition of exogenous FAD; inhibition on the addition of divalent cations, EDTA, or PCMB; little stimulation on the addition of detergents; and no increase in activity on repeated freezing and thawing. In addition, crude preparations of this oxidase were found to be relatively stable when stored up to one week either refrigerated or frozen, to have a specific activity of 2.8 nmoles/min/mg of protein, and to have a K, of 3.6 × 10− M for d,l-β-aminoisobutyric acid. Whether this high Km, is physiologically significant or not, however, will have to await further investigation. Preliminary (NH4)2SO4 fractionation and affinity chromatography studies also indicated that this enzyme appears to be a unique and specific oxidase whose activity is separable from other marker enzymes, including other oxidases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Phosphatase activity in Trypanosoma rhodesiense has been examined histochemically by light and electron microscopy and by enzymatic assay in homogenate fractions. Using a method with lead as capture ion, acid phosphatase was found in lysosome-like vesicles and in the flagellar pocket. No alkaline adenosine triphosphatase (ATPase) was detectable by this method. Direct assay of p-nitrophenylphosphatase activity in homogenate fractions showed that acid phosphatase activity was strongly membrane-bound, but that activity at pH 9 was minimal in both soluble and particulate fractions. “Endogenous” ATPase activity was localized specifically and reproducibly in the mitochondrial membranes and under the plasma membrane of the flagellum. This nonenzymic reaction product could not be eradicated by glycerol extraction or glucose depletion. Unlike the membrane staining, which was manifest only after lead treatment, heat-resistant electron-dense material was found in the matrix of lysosomal vesicles in trypanosomes fixed in glutaraldehyde only and not subjected to further treatment with heavy metal reagents. X-ray emission analysis showed the presence of calcium and phosphorus, indicating that the matrix might have a phosphate storage function.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The longitudinal flagellum of Ceratium tripos moves in two dissimilar ways: undulation and retraction. The undulatory wave is planar and has a wavelength of 74.3 ± 9.6 μm and an amplitude of 14.2 ± 2.3 μm in sea water. The beat frequency is 30 Hz at 20°C, pH 8.0. The retractile motion is unique to Ceratium and is triggered by mechanical stimulation on the cell body, especially at the tip of the apical horn. When it retracts, the longitudinal flagellum folds every 4–5 μm along the flagellum. Cinematographic study showed that the flagellum folded from tip to base and was finally installed into the sulcus, a groove on the ventral side of the cell. This motion is completed in sea water within 28 msec. The retracted flagellum then re-extends and restores the undulation within a few seconds. The flagellum unfolds in the proximal portion first, then the distal, and finally the middle portion. Fixation always triggers the retraction. Scanning electron microscopy showed that the flagellum is folded and secondarily twisted in a helix. A new fiber in addition to the flagellar axoneme was found in the retracted flagellum by phase microscopy. This fiber (R-fiber) seems to contract during the retraction to fold the flagellum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Phagocytosis of culture forms of Trypanosoma cruzi was assayed by a radioisotopic method. Purified polymorphonuclear leukocytes (PMN) were mixed with 3H-uridine-labeled T. cruzi epimastigotes in the presence or absence of anti-T. cruzi antibodies. The reaction was stopped by adding N-ethyl-maleimide, and noningested parasites were lysed by complement. The percentage of radioactivity incorporated into the PMN pellet was recorded. The phagocytosis reaction was rapid, yielding maximum incorporation at 30 min at which point the radioactivity associated with the PMN cells decreased through release of the isotope to the supernatant. The degree of incorporation of radio-labeled parasites was a function of the effector/target cell ratio and the antibody concentration. The method is suitable for the quantitative determination of phagocytosis of T. cruzi by normal PMN.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The following species of the gregarine genus Lankesteria were found in a study of ascidians from Monterey Bay, on the central California coast of the Pacific Ocean: L. abbotti n. sp. in Clavelina huntsmani, L. aplidii n. sp. in Aplidium solidum, L. ascidiae in Ciona intestinalis, L. diaphanis n. sp. in Archidistoma diaphanes, L. euherdmaniae n. sp. in Euherdmania claviformis, L. montereyensis n. sp. in Archidistoma molle, L. pescaderoensis n. sp. in Ritterella rubra, L. pittendrighi n. sp. in Ascidia ceratodes, L. psammii n. sp. in Archidistoma psammion, L. ritterellae n. sp. in Ritterella pulchra, L. ritterii n. sp. in Archidistoma ritteri, L. synoici n. sp. in Synoicum parfustis, and Lankesteria sp. in Botrylloides sp. No gregarines were seen in the following ascidians: Aplidium californicum, A. propinquum, Botryllus tuberatus, Diplosoma macdonaldi, Perophora annectens, and Polyclinum planum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The effect of holothurin (a marine biotoxin) on the resistance of mice to Trypanosoma musculi was measured by studying changes in the parasite population in vivo. Swiss Webster (SW), Beige (BG), and Black (BL) mice treated with holothurin prior to and simultaneously with infection of trypanosomes had lower parasitemias than controls. Higher levels of parasitemia were observed in mice treated after infection with trypanosomes. The timing of administration of holothurin appeared to be an important factor in the observed effect. The minor variations in the parasitemia seemed to be related to the mouse strain.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The structure of the cyst wall of the heliozoon Echinosphaerium nucleofilum has been investigated using light microscopy, scanning and transmission electron microscopy, and X-ray microanalysis. The cyst wall is a composite structure of seven or eight layers. These are: an enveloping gelatinous layer; a layer of siliceous spheroidal bodies; an electron-dense supporting membrane; a broad electron-lucent zone; an electron-dense layer; a layer of helicoidally packed material; and one or two layers with a granular appearance lying next to the plasma membrane of the encysted organism. The structure of the cyst wall closely resembles that of Actinophrys sol, confirming the close relationship of these actinophryid heliozoa while emphasizing their distinctiveness from other amoeboid protista.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Morphogenesis of cell division was investigated in Diophrys scutum, D. oligothrix, and D. appendiculata utilizing both light microscopy of living and stained specimens and SEM of preserved specimens. The cortical morphogenetic pattern of Diophrys is similar to that of other members of the family Euplotidae. The opisthe oral primordium, which develops in a subsurface pouch, forms posterior to the parental buccal cavity. The proter inherits the parental adoral zone of membranelles (AZM) apparently unchanged. The endoral membrane forms to the right of the posterior end of the AZM in the proter, in association with the developing AZM in the opisthe. The paroral cirrus and membrane develop from a single streak that first appears along the right edge of the buccal cavity in the proter to the right of the developing buccal structures of the opisthe. Frontal and transverse cirri develop in both proter and opisthe from five separate cirral primordia that form to the right of the buccal cavity. Left marginal cirri do not develop in association with the corresponding parental structures. Kinetosomes formed within the opisthe oral primordium, or kinetosomes that were part of any parental ciliary structure, do not appear to become part of any developing paroral structures, frontal, transverse, or left marginal cirri. Speciation within the genus Diophrys and evolution of the family Euplotidae as they relate to the morphogenesis of cortical structure are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Autecology (cellular organelles and secretions, encystment and dispersal abilities), environmental conditions (physiological tolerances and interaction with other organisms), and evolutionary history contribute to protist biogeography, which manifests ecological and historical aspects. Ecological biogeography is seen in the influence of geochemistry on the distribution of fresh-water phytoflagellates and algae, and of moisture and vegetation type on soil-litter protists. A temporal feature is often present because many protists encyst and respond only to certain ranges of temperature and organic content. Historical biogeography has occurred by radiative host evolution on symbiotic protozoa (e.g., termite flagellates and rumen ciliates), and by the isolating effects of water currents, temperature, and density gradients on oceanic protists (coccoliths, dinoflagellates, foraminifera, radiolaria, and tintinnines). These two aspects combine in protists living on animal surfaces. Humans affect protist biogeography by increasing parasite ranges through human migrations and by water pollution. They can diminish these situations by disease control and exploiting appropriate ciliates in sewage disposal. Many free-living protozoa appear to be cosmopolitan, but mating types and isoenzyme studies suggest that speciation with its geographic connotations may be more widespread than presently appreciated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Available evidence indicates that many of the antiprotozoal drugs currently in use significantly modify the immune response of the host. The effect depends on both the drug and the host. Some drugs enhance the immune response, some are immuno-suppressants, and others enhance some types of immune mechanisms while suppressing others. Future efforts in the development of antiprotozoal drugs should consider their effects on both the parasite and the immune response of the host. Also in the chemotherapy of protozoal infections consideration should be given to the combined usage of immunoenhancing agents and antiprotozoal drugs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A survey of protozoa polluting bottled mineral water in Mexico was carried out using samples obtained from the three best-selling brands of bottled mineral water in the country. The organisms were concentrated through filtration procedures and subsequently cultured in sterile media. The cultures were observed over four weeks, with identification to the level of genus and species. Most commonly found were the amoebae Naegleria gruberi, Acanthamoeba astronyxis, and Vahlkampfia vahlkampfi (trophic as well as cystic stages) plus one flagellate, Bodomorpha minima. No ciliates were detected. The public health importance of the findings is obvious, since some strains of Naegleria and Acanthamoeba have the potential to cause human disease that may lead to death.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Amphidinium carteri was unable to grow on nutrient-enriched seawater in the presence of 200 μg/ml fluoride (F) but could be adapted to grow successfully on this F concentration when repeatedly cultured with stepwise increases in sub-inhibitory F concentration. Electron microscopic investigation of the F-adapted dinoflagellate cells showed abnormal ultrastructural features in the chloroplast (especially the pyrenoid), mitochondria, and nucleus. Simultaneous comparison with the F-inhibited dinoflagellate cells showed that thylakoid formation was extremely disorganized by fluoride and that F-adaptation conferred a prolamellar-like configuration on the thylakoids in the center of the pyrenoid. This unexpected appearance of lamellae formation in the F-adapted cells suggested that the pyrenoid may be a center for thylakoid assembly. Such cells also showed large, intensely osmiophilic inclusions in the mitochondria. Microbodies are found in close juxtaposition to the mitochondria and chloroplast, suggesting an increased metabolic dependence on photorespiration. The F-adapted nucleus showed dark and light concentric rings in the nucleolus region, accompanied by other signs of mitotic activity, which were not observed in the F-inhibited cells. It was inferred that the F-adaptation may have required some form of genetic change resulting presumably in the development of a phenotype mutant.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The large fresh-water microaerobic amoeba Pelomyxa palustris does not contain mitochondria, but three types of bacterial endosymbionts are always present. Thus, it is of interest in the discussion of the possible origin of mitochondria from primitive prokaryotes. Gas exchanges (O2, CO2) and concentration of endosymbionts were determined in individual amoebae, in which the life cycle stage was noted. Grey type (stationary phase) amoebae had a lower O2 uptake and lower endosymbiont concentration than light type (growth phase) amoebae, and highest O2 uptake was found in centrifugal pieces of light type Pelomyxa, centrifuged in vivo, which contained nearly all of the endosymbionts. In light type amoebae, the respiratory activity was independent of O2 concentration between 1 and 21%, and, when compared on the basis of dry weight and protein, of the same order as that of other free-living protozoa. The R.Q. was slightly higher than 1, indicating that glycolysis does not play a significant role in energy metabolism. It is concluded that P. palustris is fully aerobic, and suggestions are presented as to the role of the endosymbionts in its respiratory metabolism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . A series of new in vitro systems for the cultivation of bloodstream forms of Trypanosoma (Trypanozoon) brucei brucei, T. (T.) b. rhodesiense, and T. (T.) b. gambiense was developed. The standard system consists of a feeder layer of fibroblast-like cells derived from embryos of New Zealand White rabbits (REF) or a mountain vole, Microtus montanus (MEF), with HEPES-buffered Minimum Essential Medium (MEM), with Earle's salts, supplemented with 15% inactivated rabbit serum. These two and other feeder layers were cross-checked with different sera to test for growth support of bloodstream forms of the three trypanosome subspecies studied. Cultures could be initiated with bloodstream forms from mammalian hosts or from cryopreserved stabilates. Metacyclic forms from infected Glossina m. morsitans could also be used as inoculum; they transformed within 6 h to bloodstream forms. Maintenance of cultures and growth properties are described in detail. Experiments were undertaken to confirm that the cultivated bloodstream forms still possess some of the characteristic features of pleomorphic bloodstream populations. Cultivated bloodstream forms were always infective for mice, and a surface coat could be demonstrated by electron microscopy. They could also be cyclically transmitted through tsetse flies, and the metacyclic forms from these flies could be brought back into culture. In vitro cloning with single bloodstream forms and metacyclic forms could be achieved with high cloning efficiency. The consumption of glucose and the production of pyruvate and lactate were determined.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Fathead minnows, Pimephales promelas, raised from eggs in the laboratory, were experimentally infected with oocysts of Eimeria iroquoina from either P. promelas or the common shiner, Notropis cornutus. Within intestinal epithelial cells, trophozoites thought to be derived from the sporozoites contained a prominent electron-dense refractile body. Merozoites dedifferentiated into trophic forms by losing components of their apical complex and pellicle. The inner membrane components of the pellicle appeared discontinuous, and the micronemes became enclosed within vacuoles. Prior to merozoite formation, multinucleate meronts were limited by a single membrane. Golgi complexes were associated with the nuclei of this stage. Merozoites were formed by ectomerogony in one generation and by endomerogony in the final generation. In both forms of merogony the final nuclear division was coupled with the onset of differentiation of the merozoites and featured eccentric mitotic spindles associated with centrocones located within the nuclear envelope and with the precursors of the apical complex. A Golgi complex was closely associated with the nucleus and apical tip of the forming merozoite. Unlike other Eimeria species, the complete pellicle of the merozoites of the final asexual generation of E. iroquoina was formed within the cytoplasm of the meront, without association with the limiting membrane, thus, all pellicular components are synthesized de novo. The inner membranes of the pellicle initially appeared as longitudinal strips, each of which was associated with a pair of the 22–24 subpellicular microtubules. Mature meronts of the final asexual generation averaged 9 μm in diameter and produced 13–16 merozoites. With the exception of the internal completion of the pellicle of the final generation merozoites, the basic processes of merogony in fish Eimeria species are similar to those recorded in terrestrial hosts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The glycerophospholipids of the protozoon Tetrahymena pyriformis W are unique in that the polyunsaturated fatty acid γ-linolenate (18:3Δ6,9,12) is a major component of both the sn-C-1 and sn-C-2 positions. Tetrahymena were incubated with [1-14C]γ-linolenate. The positional distribution of the radiolabeled fatty acid in the three major glycerophospholipids was determined. [1-14C]γ-linolenate was found at both carbons of the three lipids, in general agreement with the mass distribution of γ-linolenate, except for markedly greater labeling at the sn-C-2 position of phosphatidylcholine. We hypothesize that an acyltransferase exists in Tetrahymena that can esterify γ-linolenate at both carbons during glycerophospholipid biosynthesis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Promastigotes of Leismania donovani cultured for either 3 or 10 days in vitro and inoculated intracardially into golden hamsters with an equal number of organisms from either population showed a 7-fold difference in infectivity when compared at both 10 to 16 days post-infection. Reproducible histochemical staining for the promastigote enzymes glucose-6-phosphate dehydrogenase (G6PDH) and peptidase after polyacrylamide gel electrophoresis showed two isoelectric variants of G6PDH (Bands 1 and 2) that displayed a 45% decrease (Band 1) and a 60% increase (Band 2) in total activity when 3- and 10-day-old promastigores were compared. Peptidase activity, present in a single band, increased 7-fold in 10-day-old promastigotes. A decrease in the lectin-induced agglutination of promastigotes by castor bean agglutinin (RCA60), specific for D-galactose and N-acetyl-D-galactosamine, was seen when 3- and 10-day-old promastigotes are compared. Antisera raised against sonicated 10-day-old promastigotes showed a unique precipitin band between the antiserum and sonicated 10-day-old promastigotes not found between the antiserum and sonicated 3-day-old promastigotes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The compound 6-(L-erythro-1,2′,3′-trihydroxypropyl)pterin, at a concentration of 50 pg/ml (“L-erythro-neopteria”), supports half-maximal growth of Crithidia fasciculata; biopterin at a concentration of 30 pg/ml is shown to yield similar growth. N2-dimethyl-6-(L-erythro-1′,2′,3′-trihydroxypropyl)pterin (A) was inactive even at 100 ng/ml. Synergism was observed with the N2-dimethylamino derivative (A) in the presence of suboptimal biopterin, its activity then being of the order of L-erythro-neopterin. In contrast, the stereoisomeric N2-dimethyl-6-(D-erythro-1′,2′,3′-trihydroxypropyl)pterin (“dimethyl-D-erythro-neopterin”) and its 3′-mono-phosphate only slightly enhanced growth under similar conditions but both threo-isomers had no supplementary activity. Biopterin-induced growth was slowed by 6-(D-erythro1′,2′,3′-trihydroxypropyl)pterin (D-neopterin); the threo-isomers had no such effect. An adaptive demethylation capacity by growing cultures and competition of biopterin uptake by D-neopterin seems likely. The report of the occurrence in Euglena of N2-dimethyl-6-(L-threo-1′,2′,3′-trihydroxypropyl)pterin and its 3′-mono-phosphate adds further interest to our observations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We investigated the macronuclear DNA genomes of several marine and fresh-water ciliates. The marine forms studied were: Uronema nigricans, Parauronema virginianum, Parauronema acutum, and two strains of Miamiensis avidus; the fresh-water ciliates included: Tetrahymena pyriformis, Paramecium octaurelia, and P. caudatum. The organisms were cultured axenically and the DNA extracted from isolated and purified macronuclear preparations. Reassociation rate constants of purified DNA preparations used to calculate kinetic complexity were determined both optically and by hydroxyapatite chromatography. Analytical complexity was determined chemically. Ciliate macronuclear DNA appeared to reassociate as a single unique sequence, except for a small fraction (4% of the total DNA) that was repetitive and renatured rapidly. Values for the kinetic complexities of macronuclear DNA in these forms varied over a relatively narrow range, from 1.5 to 3.8 times 1010 daltons, and were only 7–15x larger than that of the bacterium Escherichia coli. On the other hand, values for analytical complexities of macronuclear DNA of marine and fresh-water ciliates varied over two orders of magnitude and were related to the size of the animals. It is suggested that ploidy levels of macronuclear DNA in these ciliates may represent a functionally permanent amplification of the genome.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Variations in DNA levels for log-phase Euglena have been shown to be directly related to the pH of the culture medium. Data are presented here for cultures grown in Cramer and Myer's medium at pH 3.0 and 6.8. DNA levels are ∼50% greater for Euglena at the higher pH value, confirming earlier reports.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Guanylate cyclase activity decreased during the division phase of heat-shock synchronized Tetrahymena pyriformis, strain GL. However, when Ca2+ was removed by EGTA to negate the effects of the Ca2+-binding protein (calmodulin), which is required for the full activity of guanylate cyclase in this organism, no significant change in the enzymatic activity was observed throughout the cell cycle. On the other hand, the reduced guanylate cyclase activity at division phase was associated with a decreased level of calmodulin content. These results suggest that fluctuations in guanylate cyclase activity during the cell cycle would be dependent on the concentration of calmodulin.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 28 (1981), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Identification and characterization of kDNA is described in the naturally occurring totally dyskinetoplastic species Trypanosoma equinum. Fluorescence microscopy of live cells, using the highly sensitive and specific probe DAPI (4,6,-diamidino-2-phenyl-indole), showed the presence of a diversity of extranuclear fluorescent bodies scattered along the length of the organism. Transmission electron microscopic studies revealed a close similarity between the distribution of these DAPI-fluorescing particles and of dense aggregates of nonfibrillar material resembling the kDNA of dyskinetoplastic strains of other species. Variable sized remnants of kDNA, occurring singly or in clusters, were found scattered throughout the mitochondrion. Analytical cesium chloride ultracentrifugation of total cellular DNA extracts showed a kDNA banding profile at a buoyant density equal to 1.691 gm/cm3, representing approximately 11% of the total cellular DNA content. Molecular spreads of isolated kDNA revealed a population of open circular molecules ranging in contour length from 0.11–9.69 μm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...