Differential courtship activity of competing guppy males (Poecilia reticulata peters; pisces: Poeciliidae) as an indicator for low concentrations of aquatic pollutants

1988 ◽  
Vol 40 (3) ◽  
pp. 396-404 ◽  
Author(s):  
Johannes Horst Schröder ◽  
Karin Peters
Keyword(s):  
Poecilia Reticulata ◽  
Aquatic Pollutants ◽  
Low Concentrations ◽  
Courtship Activity

scholarly journals Psychoactive pollution suppresses individual differences in fish behaviour

2021 ◽  
Vol 288 (1944) ◽  
pp. 20202294
Author(s):  
Giovanni Polverino ◽  
Jake M. Martin ◽  
Michael G. Bertram ◽  
Vrishin R. Soman ◽  
Hung Tan ◽  
...  
Keyword(s):  
Individual Differences ◽  
Risk Taking ◽  
Strong Evidence ◽  
Environmental Contamination ◽  
Individual Variation ◽  
Poecilia Reticulata ◽  
Fish Behaviour ◽  
Adaptive Potential ◽  
Relative Contribution ◽  
Low Concentrations

Environmental contamination by pharmaceuticals is global, substantially altering crucial behaviours in animals and impacting on their reproduction and survival. A key question is whether the consequences of these pollutants extend beyond mean behavioural changes, restraining differences in behaviour between individuals. In a controlled, two-year, multigenerational experiment with independent mesocosm populations, we exposed guppies ( Poecilia reticulata ) to environmentally realistic levels of the ubiquitous pollutant fluoxetine (Prozac). Fish (unexposed: n = 59, low fluoxetine: n = 57, high fluoxetine: n = 58) were repeatedly assayed on four separate occasions for activity and risk-taking behaviour. Fluoxetine homogenized individuals' activity, with individual variation in populations exposed to even low concentrations falling to less than half that in unexposed populations. To understand the proximate mechanism underlying these changes, we tested the relative contribution of variation within and between individuals to the overall decline in individual variation. We found strong evidence that fluoxetine erodes variation in activity between but not within individuals, revealing the hidden consequences of a ubiquitous contaminant on phenotypic variation in fish—likely to impair adaptive potential to environmental change.

A sexual pheromone in the guppy, Poecilia reticulata (Peters)

1979 ◽  
Vol 57 (1) ◽  
pp. 184-188 ◽  
Author(s):  
R. T. Crow ◽  
N. R. Liley
Keyword(s):  
Poecilia Reticulata ◽  
Male Courtship ◽  
Sexual Pheromone ◽  
Courtship Activity ◽  
Control Water

Male guppies, Poecilia reticulata, were attracted to water which had previously held con-specific females and not to control water or water in which males or ovariectomized females had been maintained. Males expressed a preference for water which had held females in the first few days of their gestation cycles over water which held midcycle (gravid) or ovariectomized females. When males were placed with an unresponsive ovariectomized female, addition of water which had contained intact females resulted in a marked increase in courtship directed towards the ovariectomized female. It is hypothesized that the female guppy releases a sexual pheromone which attracts males and stimulates increased male courtship activity. The pheromone appears to be produced in the ovary and secreted by the female at the period of maximum receptivity following parturition.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

The CM120 Biotwin: a high-contrast objective lens, optimum cryo-vacuum and improved EDX performance

1995 ◽  
Vol 53 ◽  
pp. 584-585
Author(s):  
Uwe Lücken ◽  
Michael Felsmann ◽  
Wim M. Busing ◽  
Frank de Jong
Keyword(s):  
Life Science ◽  
Focal Length ◽  
Objective Lens ◽  
High Contrast ◽  
Contrast Imaging ◽  
X Ray ◽  
Forming Mechanism ◽  
Similar Image ◽  
High Contrast Imaging ◽  
Low Concentrations

A new microscope for the study of life science specimen has been developed. Special attention has been given to the problems of unstained samples, cryo-specimens and x-ray analysis at low concentrations.A new objective lens with a Cs of 6.2 mm and a focal length of 5.9 mm for high-contrast imaging has been developed. The contrast of a TWIN lens (f = 2.8 mm, Cs = 2 mm) and the BioTWTN are compared at the level of mean and SD of slow scan CCD images. Figure 1a shows 500 +/- 150 and Fig. 1b only 500 +/- 40 counts/pixel. The contrast-forming mechanism for amplitude contrast is dependent on the wavelength, the objective aperture and the focal length. For similar image conditions (same voltage, same objective aperture) the BioTWIN shows more than double the contrast of the TWIN lens. For phasecontrast specimens (like thin frozen-hydrated films) the contrast at Scherzer focus is approximately proportional to the √ Cs.

Immunogold labeling of CMP-KDO synthetase produced by recombinant E. Coli cells

1987 ◽  
Vol 45 ◽  
pp. 924-925
Author(s):  
F. A. Durum ◽  
R. G. Goldman ◽  
T. J. Bolling ◽  
M. F. Miller
Keyword(s):  
Inclusion Bodies ◽  
Large Scale ◽  
Recombinant Dna ◽  
Test System ◽  
Cell Protein ◽  
Gram Negative Bacteria ◽  
Cytoplasmic Inclusions ◽  
Isolation And Purification ◽  
E Coli ◽  
Low Concentrations

CMP-KDO synthetase (CKS) is an enzyme which plays a key role in the synthesis of LPS, an outer membrane component unique to gram negative bacteria. CKS activates KDO to CMP-KDO for incorporation into LPS. The enzyme is normally present in low concentrations (0.02% of total cell protein) which makes it difficult to perform large scale isolation and purification. Recently, the gene for CKS from E. coli was cloned and various recombinant DNA constructs overproducing CKS several thousandfold (unpublished data) were derived. Interestingly, no cytoplasmic inclusions of overproduced CKS were observed by EM (Fig. 1) which is in contrast to other reports of large proteinaceous inclusion bodies in various overproducing recombinant strains. The present immunocytochemical study was undertaken to localize CKS in these cells.Immune labeling conditions were first optimized using a previously described cell-free test system. Briefly, this involves soaking small blocks of polymerized bovine serum albumin in purified CKS antigen and subjecting them to various fixation, embedding and immunochemical conditions.

Phase behavior of cationic and anionic surfactants at low concentrations

1992 ◽  
Vol 50 (1) ◽  
pp. 694-695
Author(s):  
E. Naranjo
Keyword(s):  
Phase Behavior ◽  
Structural Characterization ◽  
Dynamic Systems ◽  
Anionic Surfactants ◽  
Intermolecular Forces ◽  
Stable Form ◽  
Surfactant Mixtures ◽  
Low Concentrations ◽  
Cationic And Anionic Surfactants ◽  
General Method

Equilibrium vesicles, those which are the stable form of aggregation and form spontaneously on mixing surfactant with water, have never been demonstrated in single component bilayers and only rarely in lipid or surfactant mixtures. Designing a simple and general method for producing spontaneous and stable vesicles depends on a better understanding of the thermodynamics of aggregation, the interplay of intermolecular forces in surfactants, and an efficient way of doing structural characterization in dynamic systems.

Use of the Japanese Medaka ( Oryzias latipes ) and Guppy ( Poecilia reticulata ) in Carcinogenesis Testing Under National Toxicology Program Protocols

2003 ◽  
Vol 31 (1) ◽  
pp. 88-91 ◽  
Author(s):  
William E. Hawkins ◽  
William W. Walker ◽  
John W. Fournie ◽  
C. Steve Manning ◽  
Rena M. Krol
Keyword(s):  
Poecilia Reticulata ◽  
Oryzias Latipes ◽  
Japanese Medaka ◽  
National Toxicology Program
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