Traditional staining for routine diagnostic pathology including the role of tannic acid. 1. Value and limitations of the hematoxylin-eosin stain

The components of the hematoxylin and eosin (H & E) stain (i.e. hemalum and eosin Y), their contributions to the typical staining pattern, and the reasons why the H & E stains are the preferred oversight stains for routine diagnostic histopathology are discussed. The essential diagnostic significance of effective nuclear staining by hemalum, providing information on nuclear morphology and texture, is emphasized; as is the ironic advantage for routine diagnostic histopathology of the limited range of colors provided by H & E staining, that allows recognition of significant features under low microscopic magnifications. Standardization of hemalum is considered, along with probable reasons why users show resistance to such a concept. Counterstaining with anionic (acid) dyes is discussed, as is the important phenomenon of contrast. The particular advantages and disadvantages of eosin Y and phloxin B as counterstains to hemalum are outlined. The concept of an “ideal routine histological stain” is considered, and H & E is compared to such an ideal case. Finally, deficiencies of H & E staining are discussed, and a program to develop an improved oversight stain is introduced.     

1H‐NMR screening for the high‐throughput determination of genotype and environmental effects on the content of asparagine in wheat grain

Free asparagine in cereals is known to be the precursor of acrylamide, a neurotoxic and carcinogenic product formed during cooking processes. Thus, the development of crops with lower asparagine is of considerable interest to growers and the food industry. In this study, we describe the development and application of a rapid ¹H‐NMR‐based analysis of cereal flour, that is, suitable for quantifying asparagine levels, and hence acrylamide‐forming potential, across large numbers of samples. The screen was applied to flour samples from 150 bread wheats grown at a single site in 2005, providing the largest sample set to date. Additionally, screening of 26 selected cultivars grown for two further years in the same location and in three additional European locations in the third year (2007) provided six widely different environments to allow estimation of the environmental (E) and G x E effects on asparagine levels. Asparagine concentrations in the 150 genotypes ranged from 0.32 to 1.56 mg/g dry matter in wholemeal wheat flours. Asparagine levels were correlated with plant height and therefore, due to recent breeding activities to produce semi‐dwarf varieties, a negative relationship with the year of registration of the cultivar was also observed. The multisite study indicated that only 13% of the observed variation in asparagine levels was heritable, whilst the environmental contribution was 36% and the GxE component was 43%. Thus, compared to some other phenotypic traits, breeding for low asparagine wheats presents a difficult challenge.     

微量元素对金银花绿原酸合成关键酶基因LjHCT和LjC3H1表达的影响研究

绿原酸是金银花（Lonicera japonica Thunb.）入药的主要化学成分,如何稳定和提高绿原酸的含量是近年来金银花研究的热点。本研究通过对金银花分别根施Fe、B和Mo3种微量元素,比较处理前、后金银花中微量元素与绿原酸含量的变化,并定量分析3种微量元素对金银花绿原酸合成关键酶基因LjHCT和LjC3H1表达的影响。研究结果显示,高浓度的Fe处理对LjHCT基因的表达有明显的抑制作用,而中、低浓度的Fe处理可以促进LjHCT基因的表达;随着B和Mo元素浓度的提高,LjHCT基因的表达量也逐渐增加。低浓度的Fe处理可以促进LjC3H1基因的表达,而高浓度的Fe处理对LjC3H1基因的表达具有抑制作用;B元素对LjC3H1基因表达无显著影响,而高浓度的Mo处理可以促进LjC3H1基因的表达。根施中、低浓度的Fe元素,中、高浓度的Mo和B元素后金银花绿原酸含量显著增加;而根施高浓度的Fe元素后金银花中绿原酸含量显著减少。研究结果表明微量元素Fe、B和Mo可通过调节绿原酸生物合成关键酶基因的表达从而有效促进绿原酸的形成和积累。本研究为人工定向调控金银花绿原酸含量、开发人工栽培金银花专用微量元素肥料提供了理论依据。     

The leukotriene B4 receptor, BLT1, is required for the induction of experimental autoimmune encephalomyelitis

Leukotriene B₄ (LTB₄) is a potent chemoattractant and activator of neutrophils, macrophages and T cells. These cells are a key component of inflammation and all express BLT1, a high affinity G-protein-coupled receptor for LTB₄. However, little is known about the neuroimmune functions of BLT1. In this study, we describe a distinct role for BLT1 in the pathology of experimental autoimmune encephalomyelitis (EAE) and T_H1/T_H17 immune responses. BLT1 mRNA was highly upregulated in the spinal cord of EAE mice, especially during the induction phase. BLT1^−/− mice had delayed onset and less severe symptoms of EAE than BLT1^+/+ mice. Additionally, inflammatory cells were recruited to the spinal cord of asymptomatic BLT1^+/+, but not BLT1^−/− mice before the onset of disease. Ex vivo studies showed that both the proliferation and the production of IFN-γ, TNF-α, IL-17 and IL-6 were impaired in BLT1^−/− cells, as compared with BLT1^+/+ cells. Thus, we suggest that BLT1 exacerbates EAE by regulating the migration of inflammatory cells and T_H1/T_H17 immune responses. Our findings provide a novel therapeutic option for the treatment of multiple sclerosis and other T_H17-mediated diseases.     

The role of the Val57 amino‐acid residue in the hinge loop of the human cystatin C. Conformational studies of the beta2‐L1‐beta3 segments of wild‐type human cystatin C and its mutants

Human cystatin C (HCC) is one of the amyloidogenic proteins to be shown to oligomerize via a three‐dimensional domain swapping mechanism. This process precedes the formation of a stable dimer and proceeds particularly easily in the case of the L68Q mutant. According to the proposed mechanism, dimerization of the HCC precedes conformational changes within the β2 and β3 strands. In this article, we present conformational studies, using circular dichroism and MD methods, of the β2‐L1‐β3 (His43‐Thr72) fragment of the HCC involved in HCC dimer formation. We also carried out studies of the β2‐L1‐β3 peptide, in which the Val57 residue was replaced by residues promoting β‐turn structure formation (Asp, Asn, or Pro). The present study established that point mutation could modify the structure of the L1 loop in the β‐hairpin peptide. Our results showed that the L1 loop in the peptide excised from human cystatin C is broader than that in cystatin C. In the HCC protein, broadening of the L1 loop together with the unfavorable L68Q mutation in the hydrophobic pocket could be a force sufficient to cause the partial unfolding and then the opening of HCC or its L68Q mutant structure for further dimerization. We presume further that the Asp57 and Asn57 mutations in the L1 loop of HCC could stabilize the closed form of HCC, whereas the Pro57 mutation could lead to the opening of the HCC structure and then to dimer/oligomer formation. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 373–383, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com