Partner telomeres during anaphase in crane-fly spermatocytes are connected by an elastic tether that exerts a backward force and resists poleward motion

2002 ◽  
Vol 115 (7) ◽  
pp. 1541-1549 ◽  
Author(s):  
James R. LaFountain ◽  
Richard W. Cole ◽  
Conly L. Rieder

As chromosomes move polewards during anaphase in crane-fly spermatocytes,trailing arms commonly stretch backwards for a brief time, as if tethered to their partners. To test that notion, a laser microbeam was used to sever trailing arms and thereby release telomere-containing arm segments (called acentric fragments because they lack kinetochores) from segregating chromosomes. Analysis of the movement of acentric fragments after their release provided clear evidence that previously conjoined partners were indeed tethered at their telomeres and that tethers exerted backward forces that were sufficient to move the fragment across the equator and into the opposite half-spindle. To address concerns that tethers might be artifacts of in vitro cell culture, spermatocytes were fixed in situ, and stretched arms within fixed cells provided strong evidence for tethers in vivo. The substantial resistance that tethers impose on the poleward movement of chromosomes must normally be over-ridden by the poleward `pulling' forces exerted at kinetochores. In spermatocytes, poleward forces are supplied primarily by the`traction fibers' that are firmly attached to kinetochores through end-on attachments to the plus ends of kinetochore microtubules.

2013 ◽  
Vol 280 ◽  
pp. 456-461 ◽  
Author(s):  
Chia-Man Chou ◽  
Chou-Ming Yeh ◽  
Chi-Jen Chung ◽  
Ju-Liang He

Author(s):  
Hossein MODIRROUSTA ◽  
Gholamreza HABIBI ◽  
Parviz SHAYAN ◽  
Asghar AFSHARI ◽  
Ali MIRJALILI ◽  
...  

Background: The protozoan parasite Theileria annulata is the causative agent of tropical theileriosis in cattle. Vaccination is recommended by administration of attenuated schizont-infected cell lines. The expected protective immunity post-vaccination can be demonstrated by challenge test through inoculation of highly virulent infective sporozoites. The aim of this study was to produce Hyalomma anatolicum anatolicum tick infected with T. annulata (local strain) for preparation of tick-derived sporozoite stabilates for molecular characterization and infectivity test assay. Methods: A local T. annulata strain was used for experimental infection of calves. A field isolate of H. a. anatolicum was isolated, laboratory-reared and infected by blood-feeding on Theileria infected above-mentioned calves. The infectivity of calf, tick and prepared stabilate were confirmed by clinical signs of theileriosis, microscopic inspection, RT-PCR and in vitro cell culture. Results: The tick stabilate was prepared and cryopreserved in liquid nitrogen. The infectivity of the tick stabilate was verified by in vivo bioassay, in vitro cell culture infection, microscopic inspection in salivary glands and RT-PCR assay. The in vitro produced cell line in this study was characterized by T. annulata Cytochrome b gene analyzing. Conclusion: The infectivity of a new prepared tick-derived sporozoite stabilate was confirmed in susceptible calves; by microscopically, post mortem, tick microscopic and molecular assays. Moreover, naïve PBMCs were transformed and proliferated by T. annulata infected tick stabilate to immortal T. annulata schizont infected cell line. The potent infective sporozoite tick derived stabilate could be used for vaccine efficacy and challenge test as well as in vaccine development.


2008 ◽  
Vol 24 (9) ◽  
pp. 461-472 ◽  
Author(s):  
Bi-Fang Lee ◽  
Nan-Tsing Chiu ◽  
Chien-Chung Hsia ◽  
Lie-Hang Shen

2021 ◽  
pp. 73-102
Author(s):  
Shahid S. Siddiqui ◽  
Khaled Aboshamat ◽  
Sivakumar Loganathan ◽  
Zeba K. Siddiqui

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xiumei Huang ◽  
Bo Li ◽  
Lianzhong Shen

This work is to study the anti-inflammatory effect and its mechanisms of sophoridine in vitro and in vivo. For this aim, the influences of sophoridine on several inflammatory mediators were investigated. Excessive inflammatory response in vitro model was developed by using lipopolysaccharide (LPS) to stimulate the mouse peritoneal macrophages and HL-60 cells to produce IL-6 and IL-8. Carrageenin-induced mouse paw edema model was used as inflammatory response in vivo model. MTT method, ultraviolet spectrophotometric method, and radioimmunoassay were used to measure the changes of TNFα, IL-6, PGE2, and IL-8 in in vitro cell culture supernatant or in the local inflammatory exudates. The results showed that sophoridine inhibited the production of IL-8 in in vitro cell culture supernatant and inhibited the production of TNFα, PGE2, and IL-8 in the local inflammatory exudates but had no significant effects on the production of IL-6 in vitro and in vivo. It is demonstrated that sophoridine’s anti-inflammatory effect was due to its ability to inhibit the production of cytokine and inflammatory mediators.


2020 ◽  
pp. 088532822094850
Author(s):  
Elisabetta Rosellini ◽  
Niccoletta Barbani ◽  
Caterina Frati ◽  
Denise Madeddu ◽  
Diana Massai ◽  
...  

The use of injectable scaffolds to repair the infarcted heart is receiving great interest. Thermosensitive polymers, in situ polymerization, in situ cross-linking, and self-assembling peptides are the most investigated approaches to obtain injectability. Aim of the present work was the preparation and characterization of a novel bioactive scaffold, in form of injectable microspheres, for cardiac repair. Gellan/gelatin microspheres were prepared by a water-in-oil emulsion and loaded by adsorption with Insulin-like growth factor 1 to promote tissue regeneration. Obtained microspheres underwent morphological, physicochemical and biological characterization, including cell culture tests in static and dynamic conditions and in vivo tests. Morphological analysis of the microspheres showed a spherical shape, a microporous surface and an average diameter of 66 ± 17µm (under dry conditions) and 123 ± 24 µm (under wet conditions). Chemical Imaging analysis pointed out a homogeneous distribution of gellan, gelatin and Insulin-like growth factor-1 within the microsphere matrix. In vitro cell culture tests showed that the microspheres promoted rat cardiac progenitor cells adhesion, and cluster formation. After dynamic suspension culture within an impeller-free bioreactor, cells still adhered to microspheres, spreading their cytoplasm over microsphere surface. Intramyocardial administration of microspheres in a cryoinjury rat model attenuated chamber dilatation, myocardial damage and fibrosis and improved cell homing. Overall, the findings of this study confirm that the produced microspheres display morphological, physicochemical, functional and biological properties potentially adequate for future applications as injectable scaffold for cardiac tissue engineering.


2010 ◽  
Vol 8 (5) ◽  
pp. 136
Author(s):  
T. Andersen ◽  
H. Heier-Baardson ◽  
J.E. Melvik ◽  
M. Dornish

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