Direct detection of digestive enzymes in planktonic rotifers using enzyme-labelled fluorescence (ELF)

2005 ◽  
Vol 56 (2) ◽  
pp. 189 ◽  
Author(s):  
M. Štrojsová ◽  
J. Vrba
Keyword(s):  
Enzyme Assay ◽  
Direct Detection ◽  
Feeding Activity ◽  
Life Stage ◽  
Natural Populations ◽  
Trend Detection ◽  
Additional Information ◽  
New Information ◽  
Planktonic Rotifers

A novel enzyme-labelled-fluorescence (ELF) method was applied to natural populations of planktonic rotifers from a eutrophic reservoir. Direct visualisation of rotifers by this new method provided new information about enzymatic activities in situ, including detection and location of enzyme activities. Three fluorogenic substrates were used for the enzyme assay in concentrated (20–60×) samples of the rotifers. After a short (1–3 h) incubation in test tubes, samples were filtered and the rotifers on polycarbonate filters were examined using an epifluorescence microscope. Activity of phosphatases, β-N-acetylhexosaminidases and lipases were detected in some species that were regularly inspected during two seasons – most frequently in the stomach area, at the corona and, less often, in the mastax area. The results suggest that most of the detected enzymes are connected with the digestive tracts of rotifers. Also, autofluorescence of chlorophyll a enabled visualisation of the digestive tracts of the rotifers and provided additional information on the food (phytoplankton). Enzyme expression did not show any clear seasonal trend. Detection of specific enzymes varied considerably between species of rotifers and between individuals. This variability could be a result of change of feeding behaviour of rotifers in the concentrated samples and also could reflect individual differences among the rotifers in a population, such as feeding activity, age or life stage.

scholarly journals Advances in the diagnosis and treatment of leprosy

2002 ◽  
Vol 4 (15) ◽  
pp. 1-14 ◽  
Author(s):  
Vishwa M. Katoch
Keyword(s):  
Direct Detection ◽  
Genomic Structure ◽  
In Situ Hybridisation ◽  
Technological Advances ◽  
New Information ◽  
Rna Targeting ◽  
Polymerase Chain ◽  
Monitoring Treatment ◽  
Effective Drugs

Leprosy is a chronic infectious disease caused by Mycobacterium leprae that mainly affects the skin and peripheral nerves. Over recent years, many important advances have been made in developing molecular diagnostics, in identifying highly effective drugs and designing multidrug regimens for treatment, and in unravelling the genomic structure and functions of the leprosy bacillus. Using the new information about specific sequences of M. leprae, several gene probes and gene amplification systems for confirming diagnosis and monitoring treatment have been developed. Among these, polymerase chain reaction (PCR)-based methods have been useful in confirming the diagnosis in paucibacillary leprosy (where few bacilli are present). RNA-targeting systems for monitoring the progress of treatment, in situ hybridisation techniques for analysing specimens with nonspecific histological features, and molecular methods for direct detection of rifampicin/dapsone resistance are other major technological advances with immense applied value. Several effective regimens for the treatment of leprosy have been developed, which include rifampicin, clofazimine and dapsone as core drugs. Although these regimens are generally satisfactory, limitations in terms of persisting activity and late reactions/relapses in paucibacillary leprosy, and persistence of dead and/or live organisms in multibacillary forms of the disease, have been observed.

Photoinhibition of DCMU-Enhanced Fluorescence in Lake Ontario Phytoplankton

1987 ◽  
Vol 44 (12) ◽  
pp. 2144-2154 ◽  
Author(s):  
M. Putt ◽  
G. P. Harris ◽  
R. L. Cuhel
Keyword(s):  
Vertical Mixing ◽  
Natural Populations ◽  
Bright Light ◽  
Euphotic Zone ◽  
Lake Ontario ◽  
Enhanced Fluorescence ◽  
Low Light ◽  
Light Levels ◽  
Phosphorus Status

Measurement of 1-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) enhanced fluorescence (FDCMU) suggested that photoinhibition of photosynthesis was frequently an artifact of in situ bottle incubations in Lake Ontario phytoplankton. In a seasonal study, FDCMU of all populations was depressed by bright light in an incubator. However, when the euphotic zone did not exceed the depth of the mixed layer, vertical transport of phytoplankton into either low-light or dark regions apparently allowed reversal of photoinhibition of FDCMU. Advantages of FDCMU as a bioassay of vertical mixing include rapidity of response time, ease of measurement in the field, and insensitivity of this parameter to changes in phosphorus status of the population. Because of seasonal changes in the photoadaptive response of natural populations, the rate constants and threshold light levels required to cause the response must be determined at each use if the method is to be quantitative.

Methodologies for specific intron and exon RNA localization in cultured cells by haptenized and fluorochromized probes

1993 ◽  
Vol 104 (4) ◽  
pp. 1187-1197 ◽  
Author(s):  
R.W. Dirks ◽  
F.M. van de Rijke ◽  
S. Fujishita ◽  
M. van der Ploeg ◽  
A.K. Raap
Keyword(s):  
In Situ Hybridization ◽  
Cell Lines ◽  
Cultured Cells ◽  
Direct Detection ◽  
Housekeeping Genes ◽  
Housekeeping Gene ◽  
Immediate Early ◽  
High Signal ◽  
Pretreatment Conditions

We have determined optimal conditions for the detection of mRNA sequences in cultured cells by nonradioactive in situ hybridization. For this purpose a number of different cell lines have been used: rat 9G cells for the detection of human cytomegalovirus immediate early mRNA, and HeLa as well as 5637 carcinoma cells for the detection of housekeeping gene mRNAs. Extensive optimization of fixation and pretreatment conditions revealed that most intense hybridization signals are obtained when cells are grown on glass microscope slides, fixed with a mixture of formaldehyde and acetic acid, pretreated with pepsin and denatured prior to hybridization. In addition, we also studied the potential of fluorochromized probes for the direct detection of multiple RNA sequences. The optimized in situ hybridization procedure revealed that immediate early mRNA transcripts are, in addition to a cytoplasmic localization, localized within nuclei of rat 9G cells. Double hybridization experiments showed that intron and exon sequences colocalize within the main nuclear signal. In addition, the presence of small, intron-specific, fluorescent spots scattered around the main nuclear signals indicates that intron sequences which are spliced out can be visualized. Additional information about the functioning of cells could be obtained by the detection of mRNA simultaneously with bromodeoxyuridine, incorporated during S-phase, or its cognate protein. The sensitivity of these methods is such that mRNAs of abundantly expressed housekeeping genes can be detected in a variety of cell lines with high signal to noise ratios.

scholarly journals Sediment community responses to marine vs. terrigenous organic matter in a submarine canyon

2013 ◽  
Vol 10 (1) ◽  
pp. 67-80 ◽  
Author(s):  
W. R. Hunter ◽  
A. Jamieson ◽  
V. A. I. Huvenne ◽  
U. Witte
Keyword(s):  
Organic Matter ◽  
Feeding Activity ◽  
N Uptake ◽  
Bacterial Biomass ◽  
Submarine Canyon ◽  
Stable Isotope Labelling ◽  
C And N ◽  
13C Label ◽  
Experimental Treatments

Abstract. The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM) transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days) responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii) and nitrogen-poor terrigenous (Triticum aestivum) phytodetritus. 13C and 15N labels were traced into faunal biomass and bulk sediments, and the 13C label traced into bacterial polar lipid fatty acids (PLFAs). Isotopic labels penetrated to 5 cm sediment depth, with no differences between stations or experimental treatments (substrate or time). Macrofaunal assemblage structure differed between the eastern and western canyon branches. Following deposition of marine phytodetritus, no changes in macrofaunal feeding activity were observed between the eastern and western branches, with little change between 3 and 7 days. Macrofaunal C and N uptake was substantially lower following deposition of terrigenous phytodetritus with feeding activity governed by a strong N demand. Bacterial C uptake was greatest in the western branch of the Whittard Canyon, but feeding activity decreased between 3 and 7 days. Bacterial processing of marine and terrigenous OM were similar to the macrofauna in surficial (0–1 cm) sediments. However, in deeper sediments bacteria utilised greater proportions of terrigenous OM. Bacterial biomass decreased following phytodetritus deposition and was negatively correlated to macrofaunal feeding activity. Consequently, this study suggests that macrofaunal–bacterial interactions influence benthic C cycling in the Whittard Canyon, resulting in differential fates for marine and terrigenous OM.

scholarly journals Ecological interrelations of Rapana venosa (Gastropoda: Muricidae) with ichthyofauna in the Black Sea

2016 ◽  
Vol 1 (4) ◽  
pp. 76-77
Author(s):  
I. P. Bondarev
Keyword(s):  
Black Sea ◽  
Marine Ecosystem ◽  
Fish Fauna ◽  
The Black Sea ◽  
Sandy Bottom ◽  
Rapana Venosa ◽  
New Information ◽  
Bottom Zone

Systematic monitoring of ecologically significant species – predatory mollusc Rapana venosa Valenciennes, 1846 populations – is an important part of the Black Sea monitoring. The study of the role of R. venosa in contemporary marine ecosystem is of considerable interest. In June-September 2015-2016 the study of consorting relations of rapana was conducted in situ with a parallel sampling by diver. In the course of research new information about the interaction of R. venosa with the fish fauna has been obtained. Of particular importance for fishes is the presence of rapana in the sandy bottom zone, where there are no natural shelters, and food resources are limited. The most important for the fish is the presence on the rapana shells of algal fouling and epiphyton. The shells of invader – R. venosa – and its fouling create additional opportunities for the survival of some fish fauna representatives juveniles of the Black Sea. The data obtained extend the concepts of ecological role of mollusc – invader R. venosa, as well as the ecology and ethology of several fish species.

scholarly journals Chromosome Y Isodicentrics in two Cases with Ambiguous genitalia and Features of Turner Syndrome

2008 ◽  
Vol 11 (2) ◽  
pp. 51-58
Author(s):  
A Lungeanu ◽  
A Arghir ◽  
S Arps ◽  
G Cardos ◽  
N Dumitriu ◽  
...  
Keyword(s):  
Turner Syndrome ◽  
Y Chromosome ◽  
Ambiguous Genitalia ◽  
Peripheral Blood Lymphocytes ◽  
Chromosome Y ◽  
Y Chromosomes ◽  
New Information ◽  
Pathway Perturbation

Chromosome Y Isodicentrics in two Cases with Ambiguous genitalia and Features of Turner SyndromeKaryotype investigations using classical cytogenetics, fluorescencein situhybridization (FISH) and polymerase chain reaction (PCR) techniques were used for the characterization of Y chromosome structural anomalies found in two patients with ambiguous genitalia and features of Turner syndrome. Both exhibited mosaic karyotypes of peripheral blood lymphocytes. The karyotype was 45, X[90]/ 46, X, idic(Y)(p11.3).ish idic(Y) (wcpY+, DXYS130++,SRY++,DYZ3++,DYZ1++, DYS224++)[10] in one case, and the karyotype was 45, X[65]/46, X, idic(Y) (q11).ish idic(Y)(SRY++, RP11-140H23-)[35] in the other case. Derivative Y chromosomes were different in shape and size and positive for the SRY gene, a common underlying element of ambiguous genitalia phenotypes. These results add new information concerning the role of Y chromosome structural abnormalities in sex determination pathway perturbation which are poorly understood, and highlight the importance of the sex chromosomes integrity for a normal sex phenotype development.

Propeller thrust force contribution to airplane longitudinal stability

2018 ◽  
Vol 90 (9) ◽  
pp. 1474-1478
Author(s):  
Miodrag Milenković-Babić
Keyword(s):  
Stability Analysis ◽  
Thrust Force ◽  
Standard Procedure ◽  
Longitudinal Stability ◽  
Content Type ◽  
Additional Information ◽  
New Information ◽  
Practical Implications ◽  
Theoretical Results ◽  
Propeller Thrust

Purpose This paper aims to present the new information about propeller thrust force contribution to airplane longitudinal stability analysis. Design/methodology/approach The method presented in this paper is empirical, shows how propeller thrust force derivative can be obtained and gives some additional information about misinterpretation of the propeller thrust effects that are present in the current literature. Findings New information about propeller thrust force contribution to airplane longitudinal stability analysis has been presented. This information should enable more precise insight in aircraft stability analysis and better understanding of the physical process that occurs during maneuver flight. Practical implications The information presented in this paper is new and specific to the propeller aircraft configuration. The methods used here are standard procedure to evaluating propeller thrust force derivative. Originality/value The information in this paper presents theoretical results. The method for calculating thrust force contribution to the airplane longitudinal stability is given depending on the propeller type and should enable good engineering results.

scholarly journals Surface Morphology of Cometary Nuclei

1991 ◽  
Vol 116 (2) ◽  
pp. 761-767
Author(s):  
D. Möhlmann ◽  
E. Kührt
Keyword(s):  
Imaging Techniques ◽  
Cometary Nucleus ◽  
Complex Data ◽  
Cometary Nuclei ◽  
Precise Knowledge ◽  
New Information ◽  
Consistent Model ◽  
Topological Surface ◽  
In Situ Observations

Abstract.The first in situ observations of a cometary nucleus by imaging techniques on board the VEGA and Giotto spacecraft in 1986 opened the possibility of directly studying the properties and structures of a cometary surface. This new information, combined with results from other experiments made by these spacecraft and with results from laboratory experiments and Earth-bound radar observations, gave a better basis for coming from speculation to more precise knowledge in describing properties of cometary surfaces and related activity. It is the aim of this paper to discuss the different views developed to understand properties of cometary surfaces and to propose a consistent model for understanding topological surface properties and related cometary activity. We accomplish this by extending former hypotheses and approaches and making them more precise in the light of the new and more complex data.

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