365 research outputs found
āEverydayā Knowledge and a New Paradigm of Animal Research
Commentary on Marino and Allen (2017) The Psychology of Cow
Attitudes of Canadian Pig Producers Toward Animal Welfare
As part of a larger study eliciting Canadian producer and non-producer views about animal welfare, open-ended, semi-structured interviews were used to explore opinions about animal welfare of 20 Canadian pig producers, most of whom were involved in confinement-based systems. With the exception of the one organic producer, who emphasized the importance of a āānaturalāā life, participants attached overriding importance to biological health and functioning. They saw their efforts as providing pigs with dry, thermally regulated, indoor environments where animals received abundant feed, careful monitoring and where prospective disease outbreaks could be minimized and controlled. Emphasis was also placed on low-stress handling and agreeable working conditions which were believed to promote good animal care. The fact that pigs tend to respond to such conditions with steady growth reinforced the belief that good welfare was provided. Participants supported the use of sow gestation stalls, but with some reservations, and expressed concern about welfare problems that could occur if sows were grouped. Invasive procedures (castration, tail-docking, teeth clipping) were recognized as painful but were accepted because they were seen as: (1) necessary for sales or management; (2) satisfactory trade-offs to prevent worse welfare problems such as injury or infection; or (3) sufficiently short-term to be relatively unimportant. Participants were adamantly opposed to animal neglect and some welcomed actions of animal protectionists that expose poor care. Producers also welcomed natural-science-based approaches to improving animal welfare. The findings contribute to a broader effort to identify overlapping values among different stakeholder groups as a basis for formulating mutually agreeable, farm animal care and handling polices
Attitudes of Canadian Citizens Toward Farm Animal Welfare: A Qualitative Study
As part of a larger project to determine if there are animal-welfare-related values shared by some commercial foodāanimal producers and non-producers in Canada, open-ended, semi-structured interviews were conducted to elicit opinions about animal welfare among 24 urban and rural residents not involved in commercial animal production. All participants possessed a self-described interest in food animal well-being and were therefore assumed to represent the views of Canadian non-producers most apt to engage in efforts to shape the animal welfare policies of governments and businesses. Participants described animal welfare in moral or ethical terms, expressed virtually unanimous support for animals having access to ānaturalā living conditions, and (somewhat less often) linked animal welfare to positive affective states. Maintaining reasonable health and biological functioning was seen as important but was not to take precedence over the benefits of natural living. Participants favoured small family farms and unanimously objected to confinement housing. Participants did, however, offer qualified support for intensive practices and were unanimous in not assigning blame to producers, whom they regarded sympathetically. Predictably perhaps, given our sample, most were critical of industries preoccupied with profits and of consumers who unthinkingly seek cheap food. Recommended ways of improving welfare included instilling in consumers a greater appreciation for the intrinsic value of humanely reared animals, and better education of children regarding the connection between animals and food. Disagreements arose over the welfare implications of organic production and approaches to animal advocacy. Differing demographic backgrounds, experiential involvement with food animals and knowledge of food animal production practices may have influenced the nature or specificity of welfare concerns. Many participants admitted a lack of knowledge about contemporary production practices and some expressed an interest in obtaining additional knowledge. These findings contribute to a broader effort to identify shared values among different stakeholder groups as a basis for formulating widely acceptable, farm animal care and handling polices
The proteasome cap RPT5/Rpt5p subunit prevents aggregation of unfolded ricin A chain
The plant cytotoxin ricin enters mammalian cells by receptor-mediated endocytosis, undergoing retrograde transport to the endoplasmic reticulum (ER) where its catalytic A chain (RTA) is reductively separated from the holotoxin to enter the cytosol and inactivate ribosomes. The currently accepted model is that the bulk of ER-dislocated RTA is degraded by proteasomes. We show here that the proteasome has a more complex role in ricin intoxication than previously recognised, that the previously reported increase in sensitivity of mammalian cells to ricin in the presence of proteasome inhibitors simply reflects toxicity of the inhibitors themselves, and that RTA is a very poor substrate for proteasomal degradation. Denatured RTA and casein compete for a binding site on the regulatory particle of the 26S proteasome, but their fates differ. Casein is degraded, but the mammalian 26S proteasome AAA-ATPase subunit RPT5 acts as a chaperone that prevents aggregation of denatured RTA and stimulates recovery of catalytic RTA activity in vitro. Furthermore, in vivo, the ATPase activity of Rpt5p is required for maximal toxicity of RTA dislocated from the Saccharomyces cerevisiae ER. Our results implicate RPT5/Rpt5p in the triage of substrates in which either activation (folding) or inactivation (degradation) pathways may be initiated
"Everyday" Knowledge and a New Paradigm of Animal Research
Commentary on Marino and Allen (2017) The Psychology of Cow
A human embryonic kidney 293T cell line mutated at the Golgi -mannosidase II locus
Disruption of Golgi -mannosidase II activity can result in type II congenital dyserythropoietic anemia and can induce lupus-like autoimmunity in mice. Here, we isolate a mutant human embryonic kidney (HEK) 293T cell line, called Lec36, that displays sensitivity to ricin that lies between the parental HEK 293T cells, whose secreted and membrane-expressed proteins are dominated by complex-type glycosylation, and 293S Lec1 cells, which only produce oligomannose-type N-linked glycans. The stem cell marker, 19A, was transiently expressed in the HEK 293T Lec36 cells, and in parental HEK 293T cells with and without the potent Golgi -mannosidase II inhibitor, swainsonine. Negative-ion nano-electrospray ionization mass spectra of the 19A N-linked glycans from HEK 293T Lec36 and swainsonine-treated HEK 293T cells were qualitatively indistinguishable and, as shown by collision-induced dissociation spectra, dominated by hybrid-type glycosylation. Nucleotide sequencing revealed mutations in each allele of MAN2A1, the gene encoding Golgi -mannosidase II: a point mutation in one allele mapping to the active site and an in-frame deletion of twelve-nucleotides in the other. Expression of wild-type but not the mutant MAN2A1 alleles in Lec36 cells restored processing of the 19A reporter glycoprotein to complex-type glycosylation. The Lec36 cell line will be useful for expressing therapeutic glycoproteins with hybrid-type glycans and provides a sensitive host for detecting mutations in human MAN2A1 causing type II congenital dyserythropoietic anemia
Fine tuning Exo2, a small molecule inhibitor of secretion and retrograde trafficking pathways in mammalian cells
The small molecule 4-hydroxy-3-methoxybenzaldehyde (5,6,7,8-tetrahydro[1]benzothieno[2,3-
d]pyrimidin-4-yl)hydrazone (Exo2) stimulates morphological changes at the mammalian Golgi and
trans-Golgi network that are virtually indistinguishable from those induced by brefeldin A. Both
brefeldin A and Exo2 protect cells from intoxication by Shiga(-like) toxins by acting on other
targets that operate at the early endosome, but do so at the cost of high toxicity to target cells. The
advantage of Exo2 is that it is much more amenable to chemical modification and here we report a
range of Exo2 analogues produced by modifying the tetrahydrobenzothienopyrimidine core, the
vanillin moiety and the hydrazone bond that links these two. These compounds were examined for
the morphological changes they stimulated at the Golgi stack, the trans Golgi network and the
transferrin receptor-positive early endosomes and this activity correlated with their inherent
toxicity towards the protein manufacturing ability of the cell and their protective effect against
toxin challenge. We have developed derivatives that can separate organelle morphology, target
specificity, innate toxicity and toxin protection. Our results provide unique compounds with low
toxicity and enhanced specificity to unpick the complexity of membrane trafficking networks
The secretion inhibitor Exo2 perturbs trafficking of Shiga toxin between endosomes and the trans-Golgi network
The small-molecule inhibitor Exo2 {4-hydroxy-3-methoxy-(5,6,7,8-tetrahydrol[1]benzothieno[2,3-d]pyrimidin-4-yl)hydraz-one benzaldehyde} has been reported to disrupt the Golgi apparatus completely and to stimulate GolgiāER (endoplasmic reticulum) fusion in mammalian cells, akin to the well-characterized fungal toxin BFA (brefeldin A). It has also been reported that Exo2 does not affect the integrity of the TGN (trans-Golgi network), or the direct retrograde trafficking of the glycolipid-binding cholera toxin from the TGN to the ER lumen. We have examined the effects of BFA and Exo2, and found that both compounds are indistinguishable in their inhibition of anterograde transport and that both reagents significantly disrupt the morphology of the TGN in HeLa and in BS-C-1 cells. However, Exo2, unlike BFA, does not induce tubulation and merging of the TGN and endosomal compartments. Furthermore, and in contrast with its effects on cholera toxin, Exo2 significantly perturbs the delivery of Shiga toxin to the ER. Together, these results suggest that the likely target(s) of Exo2 operate at the level of the TGN, the Golgi and a subset of early endosomes, and thus Exo2 provides a more selective tool than BFA for examining membrane trafficking in mammalian cells
Impact of rare earth doping on the luminescence of lanthanum aluminum silicate glasses for radiation sensing
Large core soft glass fibers have been demonstrated to be promising candidates as intrinsic fiber sensors for radiation detection and dosimetry applications. Doping with rare earth ions enhanced their radiation sensitivity. SiO2-Al2O3-La2O3 (SAL) glasses offer easy fabrication of large core fibers with high rare earth concentration and higher mechanical strength than soft glasses. This paper evaluates the suitability of the SAL glass type for radiation dosimetry based on optically stimulated luminescence (OSL) via a comprehensive investigation of the spectroscopic and dosimetric properties of undoped and differently rare earth doped bulk SAL glass samples. Due to the low intensity of the rare earth luminescence peaks in the 250ā400 nm OSL detection range, the OSL response for all the SAL glasses is not caused by the rare earth ions but by radiation-induced defects that act as intrinsic centers for the recombination of electrons and holes produced by the ionizing radiation, trapped in fabrication induced defect centers, and then released via stimulation with 470 nm light. The rare earth ions interfere with these processes involving intrinsic centers. This dosimetric behavior of highly rare earth doped SAL glasses suggests that enhancement of OSL response requires lower rare earth concentrations and/or longer wavelength OSL detection range
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