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31.
32.
David E. Larson Ruth I. Johnson Maciej Swat Julia B. Cordero James A. Glazier Ross L. Cagan 《PLoS computational biology》2010,6(7)
We present a computer simulation and associated experimental validation of assembly of glial-like support cells into the interweaving hexagonal lattice that spans the Drosophila pupal eye. This process of cell movements organizes the ommatidial array into a functional pattern. Unlike earlier simulations that focused on the arrangements of cells within individual ommatidia, here we examine the local movements that lead to large-scale organization of the emerging eye field. Simulations based on our experimental observations of cell adhesion, cell death, and cell movement successfully patterned a tracing of an emerging wild-type pupal eye. Surprisingly, altering cell adhesion had only a mild effect on patterning, contradicting our previous hypothesis that the patterning was primarily the result of preferential adhesion between IRM-class surface proteins. Instead, our simulations highlighted the importance of programmed cell death (PCD) as well as a previously unappreciated variable: the expansion of cells'' apical surface areas, which promoted rearrangement of neighboring cells. We tested this prediction experimentally by preventing expansion in the apical area of individual cells: patterning was disrupted in a manner predicted by our simulations. Our work demonstrates the value of combining computer simulation with in vivo experiments to uncover novel mechanisms that are perpetuated throughout the eye field. It also demonstrates the utility of the Glazier–Graner–Hogeweg model (GGH) for modeling the links between local cellular interactions and emergent properties of developing epithelia as well as predicting unanticipated results in vivo. 相似文献
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Sánchez-Alcázar JA Rodríguez-Hernández A Cordero MD Fernández-Ayala DJ Brea-Calvo G Garcia K Navas P 《Apoptosis : an international journal on programmed cell death》2007,12(7):1195-1208
It has recently been shown that the microtubule cytoskeleton is reformed during the execution phase of apoptosis. We demonstrate
that this microtubule reformation occurs in many cell types and under different apoptotic stimuli. We confirm that the apoptotic
microtubule network possesses a novel organization, whose nucleation appears independent of conventional γ-tubulin ring complex
containing structures. Our analysis suggests that microtubules are closely associated with the plasma membrane, forming a
cortical ring or cellular “cocoon”. Concomitantly other components of the cytoskeleton, such as actin and cytokeratins disassemble.
We found that colchicine-mediated disruption of apoptotic microtubule network results in enhanced plasma membrane permeability
and secondary necrosis, suggesting that the reformation of a microtubule cytoskeleton plays an important role in preserving
plasma membrane integrity during apoptosis. Significantly, cells induced to enter apoptosis in the presence of the pan-caspase
inhibitor z-VAD, nevertheless form microtubule-like structures suggesting that microtubule formation is not dependent on caspase
activation. In contrast we found that treatment with EGTA-AM, an intracellular calcium chelator, prevents apoptotic microtubule
network formation, suggesting that intracellular calcium may play an essential role in the microtubule reformation. We propose
that apoptotic microtubule network is required to maintain plasma membrane integrity during the execution phase of apoptosis.
Electronic Supplementary Material Supplementary material is available in the online version of this article at . 相似文献
35.
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Paulo FP Pimenta Alessandra S Orfano Ana C Bahia Ana PM Duarte Claudia M Ríos-Velásquez Fabrício F Melo Felipe AC Pessoa Giselle A Oliveira Keillen MM Campos Luis Martínez Villegas Nilton Barnabé Rodrigues Rafael Nacif-Pimenta Rejane C Sim?es Wuelton M Monteiro Rogerio Amino Yara M Traub-Cseko José BP Lima Maria GV Barbosa Marcus VG Lacerda Wanderli P Tadei Nágila FC Secundino 《Memórias do Instituto Oswaldo Cruz》2015,110(1):23-47
In the Americas, areas with a high risk of malaria transmission are mainly located in
the Amazon Forest, which extends across nine countries. One keystone step to
understanding the Plasmodium life cycle in Anopheles species from the Amazon Region
is to obtain experimentally infected mosquito vectors. Several attempts to colonise
Ano- pheles species have been conducted, but with only short-lived success or no
success at all. In this review, we review the literature on malaria transmission from
the perspective of its Amazon vectors. Currently, it is possible to develop
experimental Plasmodium vivax infection of the colonised and field-captured vectors
in laboratories located close to Amazonian endemic areas. We are also reviewing
studies related to the immune response to P. vivax infection of Anopheles aquasalis,
a coastal mosquito species. Finally, we discuss the importance of the modulation of
Plasmodium infection by the vector microbiota and also consider the anopheline
genomes. The establishment of experimental mosquito infections with Plasmodium
falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide
interesting models for studying malaria in the Amazonian scenario is important.
Understanding the molecular mechanisms involved in the development of the parasites
in New World vectors is crucial in order to better determine the interaction process
and vectorial competence. 相似文献
37.
Antonio Dobon Pilar Cordero Fatima Kreft Søren R. Østergaard Helle Antvorskov Mats Robertsson Maria Smolander Mercedes Hortal 《The International Journal of Life Cycle Assessment》2011,16(6):537-547
Purpose
This paper is the second part of a two-paper series dealing with the sustainability evaluation of a new communicative packaging concept. The communicative packaging concept includes a device that allows changing the expiry date of the product as function of temperature during transport and storage: a flexible best-before-date (FBBD). Such device was analysed in a consumer unit consisting of a nanoclay-based polylactic acid tray filled with pork chops. 相似文献38.
The encapsulated fungus Cryptococcus neoformans is a common cause of life-threatening disease in immunocompromised individuals. Its major virulence determinant is the polysaccharide (PS) capsule. An unsolved problem in cryptococcal biology is whether the PSs composing the capsule are linear or complex branched polymers, as well as the implications of this structural composition in pathogenesis. In this study we approached the problem by combining static and dynamic light scattering, viscosity analysis, and high-resolution microscopy and correlated the findings with biological properties. Analysis of the dependence of capsular PS molecular mass and the radius of gyration provided strong evidence against a simple linear PS configuration. Shape factors calculated from light scattering measurements in solution revealed values consistent with polymer branching. Furthermore, viscosity measurements provided complementary evidence for structural branching. Electron microscopy showed PS spherical-like structures similar to other branched PS. Finally, we show that the capacity of capsular PS to interfere in complement-mediated phagocytosis, inhibit nitric oxide production by macrophage-like cells, protect against reactive oxygen species, antibody reactivity and half-life in serum were influenced by the degree of branching, providing evidence for the notion that PS branching is an important parameter in determining the biological activity of C. neoformans PS. 相似文献
39.
Petrovic AG Vantomme G Negrón-Abril YL Lubian E Saielli G Menegazzo I Cordero R Proni G Nakanishi K Carofiglio T Berova N 《Chirality》2011,23(9):808-819
The transfer of chirality from a guest molecule to an achiral host is the subject of significant interest especially when, upon chiral induction, the chiroptical response of the host/guest complex can effectively report the absolute configuration (AC) of the guest. For more than a decade, dimeric metalloporphyrin hosts (tweezers) have been successfully applied as chirality probes for determination of the AC for a wide variety of chiral synthetic compounds and natural products. The objective of this study is to investigate the utility of a new class of melamine-bridged Zn-porphyrin tweezers as sensitive AC reporters. A combined approach based on an experimental CD analysis and a theoretical prediction of the prevailing interporphyrin helicity demonstrates that these tweezers display favorable properties for chiral recognition. Herein, we discuss the application of the melamine-bridged tweezer to the chiral recognition of a diverse set of chiral guests, such as 1,2-diamines, α-amino-esters and amides, secondary alcohols, and 1,2-amino-alcohols. The bulky periphery and the presence of a rigid porphyrin linkage lead, in some cases, to a more enhanced CD sensitivity than that reported earlier with other tweezers. 相似文献
40.
Shinichiro Maruyama Toshinobu Suzaki Andreas PM Weber John M Archibald Hisayoshi Nozaki 《BMC evolutionary biology》2011,11(1):105