quantitative microscopy
Recently Published Documents


TOTAL DOCUMENTS

196
(FIVE YEARS 26)

H-INDEX

26
(FIVE YEARS 2)

2021 ◽  
Author(s):  
Ivie Aifuwa ◽  
Jude M Phillip ◽  
Byoung Kim ◽  
Teresa Luperchio ◽  
Angela Jimenez ◽  
...  

The presence of senescent cells within tissues has been functionally linked to malignant transformations. Here, using tension-gauge tethers technology, particle-tracking microrheology, and quantitative microscopy, we demonstrate that senescent associated secretory phenotype (SASP) derived from senescent fibroblasts impose nuclear lobulations and volume shrinkage on malignant cells, which stems from the loss of RhoA/ROCK/myosin II-based cortical tension. This loss in cytoskeletal tension induces decreased cellular contractility, adhesion, and increased mechanical compliance. These SASP-induced morphological changes are in part mediated by lamin A/C. These findings suggest that SASP induces a defective outside-in mechanotransduction, from actomyosin fibers in the cytoplasm to the nuclear lamina, thereby triggering a cascade of biophysical and biomolecular changes in cells that associate with malignant transformations.


2021 ◽  
Author(s):  
Keisuke Ishihara ◽  
Arghyadip Mukherjee ◽  
Elena Gromberg ◽  
Jan Brugues ◽  
Elly Tanaka ◽  
...  

Animal organs exhibit complex topologies involving cavities and tubular networks, which underlie their form and function. However, how topology emerges during organ morphogenesis remains elusive. Here, we combine tissue reconstitution and quantitative microscopy to show that trans and cis epithelial fusion govern tissue topology and shape. These two modes of topological transitions can be regulated in neuroepithelial organoids, leading to divergent topologies. The morphological space can be captured by a single control parameter which is analogous to the reduced Gaussian rigidity of an epithelial surface. Finally, we identify a pharmacologically accessible pathway that regulates the frequency of trans and cis fusion, and demonstrate the control of organoid topology and shape. The physical principles uncovered here provide fundamental insights into the self-organization of complex tissues.


Author(s):  
Brijesh Charadva ◽  
Urvashi Ghataliya ◽  
Pooja Meena ◽  
Krishna Karia ◽  
Tixa Lakhlani ◽  
...  

Launaea procumbens leaves are galactagogue, diuretic, antifungal, anorexic, anti-arthritic and hepatoprotective according to Ayurvedic texts as well as modern research. Launaea species, particularly L. pinnatifida, is mentioned as one of the sources of Gojihva, regarding which there is controversy with respect to its true botanical identity. However, no detailed anatomical, phytochemical or chromatographic investigation is available for leaf of L. procumbens which can differentiate it from L. pinnatifida. The aim of this work is to develop standardization parameters of L. procumbens leaves by performing its pharmacognostical evaluation, preliminary phytochemical screening, HPTLC and GC-MS fingerprints. Pharmacognostic investigation of the leaves was performed by its morphological study, qualitative and quantitative microscopy as well as powder microscopy. Extraction of leaves was done by maceration using methanol. This extract was used for preliminary phytochemical screening and chemoprofiling by GC-MS, as well as for developing its HPTLC fingerprint. A mobile phase system was developed by pilot TLC, following which an HPTLC fingerprint was performed using the solvent system chloroform: methanol: ethyl acetate (3:7:6). Diagnostic microscopic characters identified in powder include unicellular covering trichome, xylem vessels, anomocytic stomata, and prisms of calcium oxalate crystal. Phytochemical screening revealed the presence of phytoconstituents classes like phenolics, anthraquinones, saponin glycosides, carbohydrates, sterols, triterpenoids and flavonoids. HPTLC fingerprinting detected 6 peaks with Rf 0.25, 0.37, 0.41, 0.50, 0.65, 0.78 at 254nm and 4 peaks with Rf 0.32, 0.37, 0.50, 0.66 at 366nm. GC-MS fingerprint revealed presence of propanoic acid anhydride, valeric anhydride, 2- Pyrrolidine acetic acid, phthalan, 5- (Hydroxy methyl)-2-(dimethoxy methyl) furan, vanillin, methyl β-l-Arabino pyranoside, 1,6-anhydro-β-D-Gluco pyranose and 6-Methyl-2-Heptanone, 6-(3,5-dimethyl-2-furanyl). Present study will be very useful for herbal industry in differentiating Launaea procumbens from other species of the genus Launaea, particularly L. pinnatifida (Gojihva) as well as for authentication, standardization and detection of adulteration in the leaf formulations of Launaea procumbens.


2021 ◽  
Vol 10 (4) ◽  
pp. 230-235
Author(s):  
J. Preetham ◽  
◽  
S. Kiran ◽  
R. Sharath ◽  
P. Sivakami Sundari ◽  
...  

Background: Pharmacognostic study of medicinal plants is an important parameter for standardization and authentication of plants, with the help of which adulteration and substitution can be prevented. The present study deals with pharmacognostic profile of leaf of Bridelia scandens (Roxb).Willd. an important traditional plant, belonging to family Euphorbiaceae used to treat various ailments. Methods: The present study includes macroscopic and microscopic studies, quantitative microscopy, and physiochemical characters such as ash value, extractive values, fluorescence analysis, and total phenol and flavonoid content. Results: Macroscopically, the leaves are B. scandens are elliptic –oblong or obavate, dark green above, pale green below lateral veins. Microscopically, leaf consists of thick semicircular midrib and the lamina, cortical zone ending with thick continuous cylinder of sclerenchyma cells. Sclerenchyma cylinder completely enclosed the vascular cylinder of the midrib, consists of only continuous thick layer of phloem. Xylem cylinder consists of numerous short or long radial chains of vessels. The lateral vein is flat on the adaxial side and prominently projecting hemispherical body on the adaxial side. Powder microscopy of leaf revealed the presence of spiral xylem vessels, rosette and prismatic calcium oxalate crystals and trichomes. A Physiochemical characteristic was also determined. Conclusion: Existing literature revealed that so far, no Pharmacognostic study has been reported on the leaf of B. scandens. Findings from this investigation can be used for its identification and determination of quality and purity of medicinally important plant. Thus exploring the usefulness of pharmacognostic evaluation to validate and authenticate drug


2021 ◽  
Author(s):  
Nalin Ratnayeke ◽  
Mingyu Chung ◽  
Tobias Meyer

A fundamental concept in eukaryotic DNA replication is the temporal separation of G1 origin licensing from S phase origin firing. Re-replication and genome instability ensue if licensing occurs after DNA synthesis has started. In humans and other vertebrates, the E3 ubiquitin ligase CRL4Cdt2 starts to degrade the licensing factor Cdt1 after origins fire, raising the question of how cells prevent re-replication in early S phase. Here, using quantitative microscopy, we show that Cdt1 inhibits DNA synthesis during an overlap period when cells fire origins while Cdt1 is still present. Cdt1 inhibits DNA synthesis by suppressing CMG helicase progression at replication forks through the MCM-binding domain of Cdt1, and DNA synthesis commences once Cdt1 is degraded. Thus, instead of separating licensing from firing to prevent re-replication in early S phase, cells separate licensing from DNA synthesis through Cdt1-mediated inhibition of CMG helicase after firing.


Author(s):  
Grazyna Lietzau ◽  
Stelia Ntika ◽  
Hiranya Pintana ◽  
Linda Tracy ◽  
Thomas Klein ◽  
...  

AbstractGlucagon-like peptide-1 (GLP-1) is a peripheral incretin and centrally active peptide produced in the intestine and nucleus tractus solitarii (NTS), respectively. GLP-1 not only regulates metabolism but also improves cognition and is neuroprotective. While intestinal GLP-1-producing cells have been well characterized, less is known about GLP-1-producing neurons in NTS. We hypothesized that obesity-induced type 2 diabetes (T2D) impairs the function of NTS GLP-1-producing neurons and glycemia normalization counteracts this effect. We used immunohistochemistry/quantitative microscopy to investigate the number, potential atrophy, and activation (cFos-expression based) of NTS GLP-1-producing neurons, in non-diabetic versus obese/T2D mice (after 12 months of high-fat diet). NTS neuroinflammation was also assessed. The same parameters were quantified in obese/T2D mice treated from month 9 to 12 with two unrelated anti-hyperglycemic drugs: the dipeptidyl peptidase-4 inhibitor linagliptin and the sulfonylurea glimepiride. We show no effect of T2D on the number and volume but increased activation of NTS GLP-1-producing neurons. This effect was partially normalized by both anti-diabetic treatments, concurrent with decreased neuroinflammation. Increased activation of NTS GLP-1-producing neurons could represent an aberrant metabolic demand in T2D/obesity, attenuated by glycemia normalization. Whether this effect represents a pathophysiological process preceding GLP-1 signaling impairment in the CNS, remains to be investigated.


2021 ◽  
Author(s):  
Grazyna Lietzau ◽  
Stelia Ntika ◽  
Hiranya Pintana ◽  
Linda Tracy ◽  
Thomas Klein ◽  
...  

Abstract Glucagon-like peptide-1 (GLP-1) is a peripheral incretin and centrally active peptide produced in the intestine and nucleus tractus solitarii (NTS), respectively. GLP-1 not only regulates metabolism but also improves cognition and is neuroprotective. While intestinal GLP-1-producing cells have been well characterized, less is known about GLP-1-producing neurons in NTS. We hypothesized that obesity-induced type 2 diabetes (T2D) impairs the function of NTS GLP-1-producing neurons and glycaemia normalization counteracts this effect. We used immunohistochemistry/quantitative microscopy to investigate the number, potential atrophy, and activation (c-Fos-expression based) of NTS GLP-1-producing neurons, in non-diabetic versus obese/T2D mice (after 12 months of high-fat diet). NTS neuroinflammation was also assessed. The same parameters were quantified in obese/T2D mice treated from month 9 to 12 with two unrelated anti-hyperglycemic drugs: the dipeptidyl peptidase-4 inhibitor linagliptin and the sulfonylurea glimepiride. We show no effect of T2D on the number and volume but increased activation of NTS GLP-1-producing neurons. This effect was partially normalized by both anti-diabetic treatments, concurrent with decreased neuroinflammation. Increased activation of NTS GLP-1-producing neurons could represent an aberrant metabolic demand in T2D/obesity, attenuated by glycaemia normalization. Whether this effect represents a pathophysiological process preceding GLP-1 signaling impairment in the CNS, remains to be investigated.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
René Schneider ◽  
Kris van’t Klooster ◽  
Kelsey L. Picard ◽  
Jasper van der Gucht ◽  
Taku Demura ◽  
...  

AbstractPlants are the tallest organisms on Earth; a feature sustained by solute-transporting xylem vessels in the plant vasculature. The xylem vessels are supported by strong cell walls that are assembled in intricate patterns. Cortical microtubules direct wall deposition and need to rapidly re-organize during xylem cell development. Here, we establish long-term live-cell imaging of single Arabidopsis cells undergoing proto-xylem trans-differentiation, resulting in spiral wall patterns, to understand microtubule re-organization. We find that the re-organization requires local microtubule de-stabilization in band-interspersing gaps. Using microtubule simulations, we recapitulate the process in silico and predict that spatio-temporal control of microtubule nucleation is critical for pattern formation, which we confirm in vivo. By combining simulations and live-cell imaging we further explain how the xylem wall-deficient and microtubule-severing KATANIN contributes to microtubule and wall patterning. Hence, by combining quantitative microscopy and modelling we devise a framework to understand how microtubule re-organization supports wall patterning.


2020 ◽  
Author(s):  
Paul Kefer ◽  
Fadil Iqbal ◽  
Maelle Locatelli ◽  
Josh Lawrimore ◽  
Mengdi Zhang ◽  
...  

ABSTRACTImage-based particle tracking is an essential tool to answer research questions in cell biology and beyond. A major challenge of particle tracking in living systems is that low light exposure is required to avoid phototoxicity and photobleaching. In addition, high-speed imaging used to fully capture particle motion dictates fast image acquisition rates. Short exposure times come at the expense of tracking accuracy. This is generally true for quantitative microscopy approaches and particularly relevant to single molecule tracking where the number of photons emitted from a single chromophore is limited. Image restoration methods based on deep learning dramatically improve the signal-to-noise ratio in low-exposure datasets. However, it is not clear whether images generated by these methods yield accurate quantitative measurements such as diffusion parameters in (single) particle tracking experiments. Here, we evaluate the performance of two popular deep learning denoising software packages for particle tracking, using synthetic datasets and movies of diffusing chromatin as biological examples. With synthetic data, both supervised and unsupervised deep learning restored particle motions with high accuracy in two-dimensional datasets, whereas artifacts were introduced by the denoisers in 3D datasets. Experimentally, we found that, while both supervised and unsupervised approaches improved the number of trackable particles and tracking accuracy, supervised learning generally outperformed the unsupervised approach, as expected. We also highlight that with extremely noisy image sequences, deep learning algorithms produce deceiving artifacts, which underscores the need to carefully evaluate the results. Finally, we address the challenge of selecting hyper-parameters to train convolutional neural networks by implementing a frugal Bayesian optimizer that rapidly explores multidimensional parameter spaces, identifying networks yielding optional particle tracking accuracy. Our study provides quantitative outcome measures of image restoration using deep learning. We anticipate broad application of the approaches presented here to critically evaluate artificial intelligence solutions for quantitative microscopy.


Sign in / Sign up

Export Citation Format

Share Document