การวจยเชงคณภาพ เปนเครองมอสำคญอยางหนงสำหรบทำความเขาใจสงคมและพฤตกรรมมนษย การวจยแบบการสรางทฤษฎจากขอมล กเปนหนงในหลายระเบยบวธการวจยเชงคณภาพทกำลงไดรบความสนใจ และเปนทนยมเพมสงขนเรอยๆ จากนกวชาการ และนกวจยในสาขาสงคมศาสตร และศาสตรอนๆ เชน พฤตกรรมศาสตร สงคมวทยา สาธารณสขศาสตร พยาบาลศาสตร จตวทยาสงคม ศกษาศาสตร รฐศาสตร และสารสนเทศศกษา ดงนน หนงสอเรอง “ConstructingGrounded Theory: A Practical Guide through Qualitative Analysis” หรอ “การสรางทฤษฎจากขอมล:แนวทางการปฏบตผานการวเคราะหเชงคณภาพ” จะชวยใหผอานมความรความเขาใจถงพฒนาการของปฏบตการวจยแบบสรางทฤษฎจากขอมล ตลอดจนแนวทาง และกระบวนการปฏบตการวจยอยางเปนระบบ จงเปนหนงสอทควรคาแกการอานโดยเฉพาะนกวจยรนใหม เพอเปนแนวทางในการนำความรความเขาใจไประยกตในงานวจยของตน อกทงนกวจยผเชยวชาญสามารถอานเพอขยายมโนทศนดานวจยใหกวางขวางขน

Constructing Grounded Theory: A Practical Guide through Qualitative Analysis

Lactic acid bacteria of foods and their current taxonomy.

Proteins are one of the most abundant and diverse classes of antigens to which the immune system can respond. These include trarisplantation antigens, anti­ gens of infectious and parasitic organisms, and allergens. An understanding of host defense mechanisms and of the ability to distinguish self from nonself requires a knowledge of the structural basis for protein antigenicity. The advent of hybridoma technology ( 1 ) to produce monoclonal antibodies, each of which

The antigenic structure of proteins: a reappraisal

In this review, we first consider the inherent structural constraints for binding of a peptide to MHC class II molecules. Such parameters at the site of TCR recognition are dependent upon the efficient generation of the antigenic determinant during natural processing of the whole protein antigen. Strikingly, only a minor fraction of such potential determinants on an antigen are presented in an immunodominant manner, while the remaining peptides are silent (cryptic). Why one determinant is selected while the majority are neglected is still unresolved, but we review the experimental evidence pertaining to this choice. Thus, features of the antigen remote from the actual determinant can either steer processing toward disclosure or revelation of a determinant, or interfere with the binding of peptides to MHC (hinderotopy). The evidence is reviewed for "MHC-guided processing," where the unfolding antigen binds at an early stage to an MHC molecule through its most available and affine agretope and then is trimmed down to final size, while the rest of the molecule, including cryptic determinants, is discarded. Different MHC molecules can compete for determinants at an early stage of processing when the antigen is close to its original length. There are shifts in the hierarchy of display of dominant and cryptic determinants, and these shifts relate to local inflammatory states, to changes in the state or composition of the APC population, and to aspects of exogenous vs endogenous processing. The impact of this differential display of determinants on tolerance and autoimmunity is discussed.

Dominance and Crypticity of T Cell Antigenic Determinants

Flavour development in dairy fermentations, most notably cheeses, results from a series of (bio)chemical processes in which the starter cultures provide the enzymes. Particularly the enzymatic degradation of proteins (caseins) leads to the formation of key-flavour components, which contribute to the sensory perception of dairy products. More specifically, caseins are degraded into peptides and amino acids and the latter are major precursors for volatile aroma compounds. In particular, the conversion of methionine, the aromatic and the branched-chain amino acids are crucial. A lot of research has focused on the degradation of caseins into peptides and free amino acids, and more recently, enzymes involved in the conversion of amino acids were identified. Most data are generated on Lactococcus lactis, which is the predominant organism in starter cultures used for cheese-making, but also Lactobacillus, Streptococcus, Propionibacterium and species used for surface ripening of cheeses are characterised in their flavour-forming capacity. In this paper, various enzymes and pathways involved in flavour formation will be highlighted and the impact of these findings for the development of industrial starter cultures will be discussed.

Flavour formation by lactic acid bacteria and biochemical flavour profiling of cheese products

We have examined the ability of two purified peptide fragments derived from hen (chicken) egg-white lysozyme (HEL); N-terminal, Co-terminal peptide (a.a. 1--17:cys 6--cys 127:120--129) and mixed disulfide LII peptide (LII) (a.a. 13--105) to induce antigen-specific suppression or help in B10 (H-2b) nonresponder and B10.A (H-2a) responder mice. An anti-HEL primary in vitro antibody response can be obtained in either strain by stimulation with HEL coupled to erythrocytes (RBC). Preimmunization with HEL-complete Freund's adjuvant-(CFA) or N-C-CFA-induced suppression of the anti-HEL PFC response to HEL-RBC in spleen cell cultures from B10 mice, whereas helper activity was demonstrated in cultures from B10.A mice similarly immunized. LII-CFA priming elicited helper cells in both C57BL/10 Sn (B10) and B10.A/SgSn (B10.A) mice. The genetic nonresponsiveness of B10 mice to HEL can therefore be attributed to the activation of suppressor T cells by a limited portion of the molecule (e.g., N-C) which prevent the potential response directed against other epitopes on the same molecule (e.g., LII). One manifestation of major histocompatibility complex gene activity appears to be the intramolecular selection of different antigenic determinants leading to activation of functionally different T-cell subpopulations.

https://rupress.org/jem/article-pdf/150/2/293/1090313/293.pdf

Fine specificity of regulatory T cells. II. Suppressor and helper T cells are induced by different regions of hen egg-white lysozyme in a genetically nonresponder mouse strain.

The characterization of several isolates of a new lactic acid bacterium which produces a malty aroma is presented. Strains MX5R, MX5S, 674S, and 628S were asporogenous, catalase-negative, gram-positive, aciduric rods of varying length which did not reduce nitrate. The above strains also formed L(+)-lactic acid, produced 0.3 to 0.4% acidity in sterile milk, and grew at 7, 15, 25, and 32 C but not at 45 C. In addition, all strains produced limited amounts of 2 from gluconate, did not produce CO2 from glucose, required riboflavin and folic acid but not thiamine for growth, and demonstrated fructose-1,6-diphosphate aldolase (EC 4.1.2.13) activity. The guanine plus cytosine contents of deoxyribonucleic acid (DNA) extracted from representative strains MX5R and MX5S were 36.0 and 36.1 mol%, respectively. All isolates produced an extracellular nuclease which hydrolyzed ribonucleic acid as well as DNA. Like Streptococcus lactis subsp. maltigenes, all strains produced 2-methylpropanal, 2-methylpropanol, 3-methylbutanal, and 3-methylbutanol in skim milk and Trypticase soy broth. The characteristic malty aroma is most likely due to the production of the above aldehydes. On the basis of the data presented, the malty strains were placed in a new species, Lactobacillus maltaromicus, in the subgenus Streptobacterium. Strain MX5 (ATCO 27865) was designated the type strain of L. maltaromicus.

Lactobacillus maltaromicus, a New Species Producing a Malty Aroma1

We have demonstrated the induction of suppressor T cells of highly restricted specificity in a nonresponder strain. HEL (hen egg-white lysozyme) fails to elicit an antibody response in C57BL/10 (B10) mice whereas the closely related REL (ring-necked pheasant egg-white lysozyme) is strongly immunogenic. However, an anti-HEL primary antibody response can be obtained in B10 mice in vivo or in vitro by coupling HEL to red blood cells (RBC). Preimmunization with HEL-CFA induced reduction of the anti-HEL PFC response to a subsequent challenge with HEL-RBC. Suppression was demonstrated by in vitro mixing experiments and was mediated with remarkable efficiency by I-J positive suppressor T cells. Suppression was specific for the anti-HEL response and did not affect the anti-RBC response. Both IgM and IgG anti-HEL in vivo antibody responses showed 70 to 80% suppression. Relatively high doses of antigen were required to generate efficient suppression. Optimal suppression was reached within 4 weeks after HEL priming and remained maximal at least 9 weeks after priming. Fine specificity in the expression of suppressive activity was displayed by HEL-specific suppressor cells that were not able to suppress an anti-REL response. Furthermore, REL priming did not suppress an in vitro anti-HEL response to HEL-RBC. The close similarity in amino acid sequence and in B cell cross-reactivity between HEL and REL, contrasted with the lack of REL recognition by HEL-specific suppressor T cells, indicates that a limited region on the nonimmunogenic HEL, absent on REL, can account for the induction of suppression.

The Fine Specificity of Regulatory T Cells I. Hen Egg-White Lysozyme-Induced Suppressor T Cells in a Genetically Nonresponder Mouse Strain Do Not Recognize a Closely Related Immunogenic Lysozyme

Alexander Miller

Papers

Fine specificity of regulatory T cells. II. Suppressor and helper T cells are induced by different regions of hen egg-white lysozyme in a genetically nonresponder mouse strain.

Lactobacillus maltaromicus, a New Species Producing a Malty Aroma1

The Fine Specificity of Regulatory T Cells I. Hen Egg-White Lysozyme-Induced Suppressor T Cells in a Genetically Nonresponder Mouse Strain Do Not Recognize a Closely Related Immunogenic Lysozyme

Ester Production by Pseudomonas fragi. I. Identification and Quantification of Some Esters Produced in Milk Cultures

Synthetic Signal Peptides Specifically Recognize SecA and Stimulate ATPase Activity in the Absence of Preprotein