scholarly journals The use of optical tweezers to study sperm competition and motility in primates

2007 ◽  
Vol 5 (20) ◽  
pp. 297-302 ◽  
Author(s):  
Jaclyn M Nascimento ◽  
Linda Z Shi ◽  
Stuart Meyers ◽  
Pascal Gagneux ◽  
Naida M Loskutoff ◽  
...  
Keyword(s):  
Sperm Competition ◽  
Optical Tweezers ◽  
Biomechanical Properties ◽  
Primate Species ◽  
Laser Tweezers ◽  
Biological Cells ◽  
Evolutionary Effect ◽  
Non Invasive ◽  
Species Specific ◽  
Two Parameters

Optical trapping is a non-invasive biophysical tool which has been widely applied to study physiological and biomechanical properties of cells. Using laser ‘tweezers’ in combination with custom-designed computer tracking algorithms, the swimming speeds and the relative swimming forces of individual sperm can be measured in real time. This combination of physical and engineering tools has been used to examine the evolutionary effect of sperm competition in primates. The results demonstrate a correlation between mating type and sperm motility: sperm from polygamous (multi-partner) primate species swim faster and with greater force than sperm from polygynous (single partner) primate species. In addition, sperm swimming force linearly increases with swimming speed for each species, yet the regression relating the two parameters is species specific. These results demonstrate the feasibility of using these tools to study rapidly moving (μm s −1 ) biological cells.

scholarly journals A Review of Murine Cytomegalovirus as a Model for Human Cytomegalovirus Disease—Do Mice Lie?

2020 ◽  
Vol 22 (1) ◽  
pp. 214
Author(s):  
Michelle A. Fisher ◽  
Megan L. Lloyd
Keyword(s):  
Human Cytomegalovirus ◽  
Murine Cytomegalovirus ◽  
Clinical Samples ◽  
Mouse Strains ◽  
Cytomegalovirus Disease ◽  
Wild Mice ◽  
Congenital Cytomegalovirus ◽  
Non Invasive ◽  
Species Specific ◽  
Disseminated Disease

Since murine cytomegalovirus (MCMV) was first described in 1954, it has been used to model human cytomegalovirus (HCMV) diseases. MCMV is a natural pathogen of mice that is present in wild mice populations and has been associated with diseases such as myocarditis. The species-specific nature of HCMV restricts most research to cell culture-based studies or to the investigation of non-invasive clinical samples, which may not be ideal for the study of disseminated disease. Initial MCMV research used a salivary gland-propagated virus administered via different routes of inoculation into a variety of mouse strains. This revealed that the genetic background of the laboratory mice affected the severity of disease and altered the extent of subsequent pathology. The advent of genetically modified mice and viruses has allowed new aspects of disease to be modeled and the opportunistic nature of HCMV infection to be confirmed. This review describes the different ways that MCMV has been used to model HCMV diseases and explores the continuing difficulty faced by researchers attempting to model HCMV congenital cytomegalovirus disease using the mouse model.

Large Deformation of Biological Cells by Optical Tweezers

2003 ◽  
Author(s):  
S. Suresh ◽  
C. T. Lim ◽  
M. Dao
Keyword(s):  
Optical Tweezers ◽  
Mechanical Test ◽  
Living Cells ◽  
Test Methods ◽  
Mechanical Forces ◽  
Deformation Characteristics ◽  
Biological Cells ◽  
Whole Cells ◽  
Aspiration Technique ◽  
Stress States

The chemical and biological functions of living cells are known to be influenced strongly by mechanical forces and deformation, and the ability of cells to detect and support forces, in turn, is also affected by chemical and biological factors. Furthermore, the progression of a number of inherited and infectious diseases have also been identified to have a strong correlation with the mechanical deformation characteristics of biological cells. Consequently, the deformation characteristics of whole cells and cell membranes have long been investigated using a variety of experimental methods, such as the micropipette aspiration technique, and by computational modeling (see, for example, refs. [1, 2]). Recent advances in experimental techniques capable of probing mechanical forces and displacements to a resolution of picoNewton and nanometer, respectively, have facilitated use of mechanical test methods for living cells whereby precise measurements of response under different stress states could be investigated.

scholarly journals Hemodynamic forces can be accurately measured in vivo with optical tweezers

2017 ◽  
Author(s):  
Sébastien Harlepp ◽  
Fabrice Thalmann ◽  
Gautier Follain ◽  
Jacky G. Goetz
Keyword(s):  
Optical Tweezers ◽  
Cell Biology ◽  
Accurate Determination ◽  
Force Measurements ◽  
Hemodynamic Forces ◽  
Non Invasive ◽  
Drag Forces ◽  
Measured Flow ◽  
Living Organisms

AbstractForce sensing and generation at the tissular and cellular scale is central to many biological events. There is a growing interest in modern cell biology for methods enabling force measurements in vivo. Optical trapping allows non-invasive probing of pico-Newton forces and thus emerged as a promising mean for assessing biomechanics in vivo. Nevertheless, the main obstacles rely in the accurate determination of the trap stiffness in heterogeneous living organisms, at any position where the trap is used. A proper calibration of the trap stiffness is thus required for performing accurate and reliable force measurements in vivo. Here, we introduce a method that overcomes these difficulties by accurately measuring hemodynamic profiles in order to calibrate the trap stiffness. Doing so, and using numerical methods to assess the accuracy of the experimental data, we measured flow profiles and drag forces imposed to trapped red blood cells of living zebrafish embryos. Using treatments enabling blood flow tuning, we demonstrated that such method is powerful in measuring hemodynamic forces in vivo with accuracy and confidence. Altogether, this study demonstrates the power of optical tweezing in measuring low range hemodynamic forces in vivo and offers an unprecedented tool in both cell and developmental biology.

Non-Invasive Monitoring of Hemodynamic Parameters during Hemodialysis

1995 ◽  
Vol 18 (9) ◽  
pp. 499-503 ◽  
Author(s):  
F. Pizzarelli ◽  
P. Dattolo ◽  
M. Piacenti ◽  
M.A. Morales ◽  
T. Cerrai ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Blood Volume ◽  
Impedance Cardiography ◽  
Hemodynamic Parameters ◽  
Non Invasive ◽  
Transthoracic Impedance ◽  
Cardiac Output Index ◽  
On Line ◽  
Two Parameters

We studied in 13 hemodialysis patients intradialytic variations of blood volume (BV) and cardiac output, by means of non-invasive methods. We found a weak correlation, r 0.2 or less, between BV variations and intradialysis blood pressure variations. The sensitivity of the former in describing the variations of the latter was only 32%. During the 30 min preceeding the hypotensive crisis the percent BV variations did not show any predictive trend. On the contrary, refilling increased as blood pressure dropped and a weak inverse relation (r -0.35) was found between these two parameters. Unstable patients had predialytic blood volume values significantly lower than stable ones and comparable to healthy subjects. On the contrary, the correlation between percent variations of cardiac output index and MAP was 0.68 with a sensitivity and specificity of 90% and 59%, respectively. Unfortunately these promising results were obtained only with an estimate of cardiac output obtained by echocardiography and not by transthoracic impedance cardiography, which is much more feasible than the former as on-line monitoring of cardiac output. On-line monitoring of hemodynamic parameters is an appealing but still unsolved task.

scholarly journals Enhancing Double-Beam Laser Tweezers Raman Spectroscopy (LTRS) for the Photochemical Study of Individual Airborne Microdroplets

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3325 ◽  
Author(s):  
Jovanny Gómez Castaño ◽  
Luc Boussekey ◽  
Jean Verwaerde ◽  
Myriam Moreau ◽  
Yeny Tobón
Keyword(s):  
Raman Spectroscopy ◽  
Optical Tweezers ◽  
Photochemical Reactions ◽  
Laser Tweezers ◽  
New Device ◽  
Spatially Resolved ◽  
Beam Laser ◽  
Coupling System ◽  
Double Beam ◽  
Levitated Droplets

A new device and methodology for vertically coupling confocal Raman microscopy with optical tweezers for the in situ physico- and photochemical studies of individual microdroplets (Ø ≤ 10 µm) levitated in air is presented. The coupling expands the spectrum of studies performed with individual particles using laser tweezers Raman spectroscopy (LTRS) to photochemical processes and spatially resolved Raman microspectroscopy on airborne aerosols. This is the first study to demonstrate photochemical studies and Raman mapping on optically levitated droplets. By using this configuration, photochemical reactions in aerosols of atmospheric interest can be studied on a laboratory scale under realistic conditions of gas-phase composition and relative humidity. Likewise, the distribution of photoproducts within the drop can also be observed with this setup. The applicability of the coupling system was tested by studying the photochemical behavior of microdroplets (5 µm < Ø < 8 µm) containing an aqueous solution of sodium nitrate levitated in air and exposed to narrowed UV radiation (254 ± 25 nm). Photolysis of the levitated NaNO3 microdroplets presented photochemical kinetic differences in comparison with larger NaNO3 droplets (40 µm < Ø < 80 µm), previously photolyzed using acoustic traps, and heterogeneity in the distribution of the photoproducts within the drop.

scholarly journals Microbial control of host gene regulation and the evolution of host–microbiome interactions in primates

2020 ◽  
Vol 375 (1808) ◽  
pp. 20190598 ◽  
Author(s):  
Laura Grieneisen ◽  
Amanda L. Muehlbauer ◽  
Ran Blekhman
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Host Species ◽  
Evolutionary Dynamics ◽  
Microbial Control ◽  
Host Gene ◽  
Primate Species ◽  
Microbiome Composition ◽  
Wide Range ◽  
Species Specific

Recent comparative studies have found evidence consistent with the action of natural selection on gene regulation across primate species. Other recent work has shown that the microbiome can regulate host gene expression in a wide range of relevant tissues, leading to downstream effects on immunity, metabolism and other biological systems in the host. In primates, even closely related host species can have large differences in microbiome composition. One potential consequence of these differences is that host species-specific microbial traits could lead to differences in gene expression that influence primate physiology and adaptation to local environments. Here, we will discuss and integrate recent findings from primate comparative genomics and microbiome research, and explore the notion that the microbiome can influence host evolutionary dynamics by affecting gene regulation across primate host species. This article is part of the theme issue ‘The role of the microbiome in host evolution’.

Species-specific mitochondrial DNA markers for identification of non-invasive samples from sympatric carnivores in the Iberian Peninsula

2007 ◽  
Vol 9 (3) ◽  
pp. 681-690 ◽  
Author(s):  
Carlos A. Fernandes ◽  
Catarina Ginja ◽  
Iris Pereira ◽  
Rogério Tenreiro ◽  
Michael W. Bruford ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Iberian Peninsula ◽  
Dna Markers ◽  
Non Invasive ◽  
Sympatric Carnivores ◽  
Species Specific
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