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We found that exposure to room temperature (RT/21°C) causes apoptosis in HL-60 cells. Here we characterized RT-induced apoptosis in HL-60. After exposure to RT, apoptosis starts within 6 h and more than 80% of the cells underwent apoptosis within 20 h. All cells, however, were committed to apoptosis after 16 h and no viable cells could be recovered. The caspase-1 inhibitor (YVAD-CHO) effectively blocked apoptosis, whereas the caspase-3 inhibitor (DEVD-CHO) did not. About 20% of newly obtained early passage HL-60 cells (passage 10) also underwent apoptosis by RT treatment. These data suggest that some population in HL-60 which responds to RT with apoptosis became dominant during passaging.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2014-02-26T17:23:42Z No. of bitstreams: 1 WOS000233520700034.pdf: 595992 bytes, checksum: f004788d490756675a8f76c182ea544c (MD5) Made available in DSpace on 2014-02-26T17:23:42Z (GMT). No. of bitstreams: 1 WOS000233520700034.pdf: 595992 bytes, checksum: f004788d490756675a8f76c182ea544c (MD5) Previous issue date: 2005-11-21 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:02:21Z No. of bitstreams: 1 WOS000233520700034.pdf: 595992 bytes, checksum: f004788d490756675a8f76c182ea544c (MD5) Made available in DSpace on 2014-05-20T14:02:21Z (GMT). No. of bitstreams: 1 WOS000233520700034.pdf: 595992 bytes, checksum: f004788d490756675a8f76c182ea544c (MD5) Previous issue date: 2005-11-21 The 1.7 angstrom resolution crystal structure of recombinant family G/11 beta-1,4-xylanase (rXynA) from Bacillus subtilis 1A1 shows a jellyroll fold in which two curved P-sheets form the active-site and substrate-binding cleft. The onset of thermal denaturation of rXynA occurs at 328 K, in excellent agreement with the optimum catalytic temperature. Molecular dynamics simulations at temperatures of 298-328 K demonstrate that below the optimum temperature the thumb loop and palm domain adopt a closed conformation. However, at 328 K these two domains separate facilitating substrate access to the active-site pocket, thereby accounting for the optimum catalytic temperature of the rXynA. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved. UNESP, IBILCE, Dept Phys, São Paulo, Brazil Univ São Paulo, FMRP, Dept Cellular & Mol Biol, BR-14049 Ribeirao Preto, SP, Brazil Univ São Paulo, FFCLRP, Dept Chem, BR-14049 Ribeirao Preto, SP, Brazil UNESP, IBILCE, Dept Phys, São Paulo, Brazil

Subfractionation of chloroplast thylakoids at elevated temperatures shows that above 35°C the photosystem II core and some of its light-harvesting complex (LHC-II) migrates laterally from the appressed thylakoid regions out to the non-appressed regions, leaving behind free LHC-II in the appressions. These structural rearrangements of the thylakoid membrane are largely reversible upon lowering the temperature and may play a physiological role in preventing overexcitation of photosystem II under high light intensities which normally induce elevated leaf temperatures.

To obtain a detailed understanding of both the general structure and function of specific members of the class of hemoproteins, comparative studies using homologous proteins from a wide variety of organisms are very useful. Myoglobins from a number of invertebrate species have been characterized both structurally and functionally [ 11. Myoglobin of AppZysia limacina was isolated, characterized [2,3] and several structural and functional properties have been studied [4-71. Applysia brasiliana is common on the eastern coast of Brazil. myoglobin was dialysed against the appropriate buffer to remove free spin label. The buffers used were Tris 0.05 M with adjusted pH values. EPR spectra were taken with a Varian X band E-9 spectrometer equipped with a system for temperature control.

The UV absorption of HMM (heavy meromyosin) was measured at various temperatures with a computerized spectrophotometer system. HMM showed temperature-induced absorption changes in the presence and absence of nucleotides. The temperature-induced absorption change at 293 nm, which is due to conformational changes around the tryptophan residues of HMM, was enhanced in the presence of nucleotides. The temperature-induced difference spectra of HMM + AMPPNP relative to HMM obtained by using a conventional spectrophotometer [(1977) J. Biochem. (Tokyo) 81, 313–320] could be reproduced by subtracting the temperature-induced spectral changes of HMM from those of HMM + AMPPNP.