Role of calcium in signal transduction during the hypersensitive response caused by basidiospore-derived infection of the cowpea rust fungus

The hypersensitive response (HR) of disease-resistant plant cells to fungal invasion is a rapid cell death that has some features in common with programmed cell death (apoptosis) in animals. We investigated the role of cytosolic free calcium ([Ca2+]i) in the HR of cowpea to the cowpea rust fungus. By using confocal laser scanning microscopy in conjunction with a calcium reporter dye, we found a slow, prolonged elevation of [Ca2+]i in epidermal cells of resistant but not susceptible plants as the fungus grew through the cell wall. [Ca2+]i levels declined to normal levels as the fungus entered and grew within the cell lumen. This elevation was related to the stage of fungal growth and not to the speed of initiation of subsequent cell death. Elevated [Ca2+]i levels also represent the first sign of the HR detectable in this cowpea-cowpea rust fungus system. The increase in [Ca2+]i was prevented by calcium channnel inhibitors. This effect was consistent with pharmacological tests in which these inhibitors delayed the HR. The data suggest that elevation of [Ca2+]i is involved in signal transduction leading to the HR during rust fungal infection.     

Minimal aerobic sludge retention time in biological phosphorus removal systems

The methodology for determination of the minimally required aerobic sludge retention time (SRTminaer) in biological phosphorus removal (BPR) systems is presented in this article. Contrary to normal biological conversions, the BPR process is not limited by a SRTmin resulting from the maximum growth rate of the organisms. This is because the aerobic SRT should be long enough to oxidize the amount of poly-hydroxy-alkanoates (PHA) stored in the anaerobic phase. This means that the SRTminaer will primarily depend on the PHA conversion kinetics and the maximal achievable PHA content in the cell (storage capacity). The model for the prediction of the minimally required aerobic SRT as a function of kinetic and process parameters was developed and compared with experimental data used to evaluate several operational aspects of BPR in a sequencing batch reactor (SBR) system. The model was proved as capable of describing them satisfactorily.Copyright 1998 John Wiley & Sons, Inc.     

Cellular basis of urothelial squamous metaplasia: roles of lineage heterogeneity and cell replacement

Although the epithelial lining of much of the mammalian urinary tract is known simply as the urothelium, this epithelium can be divided into at least three lineages of renal pelvis/ureter, bladder/trigone, and proximal urethra based on their embryonic origin, uroplakin content, keratin expression pattern, in vitro growth potential, and propensity to keratinize during vitamin A deficiency. Moreover, these cells remain phenotypically distinct even after they have been serially passaged under identical culture conditions, thus ruling out local mesenchymal influence as the sole cause of their in vivo differences. During vitamin A deficiency, mouse urothelium form multiple keratinized foci in proximal urethra probably originating from scattered K14-positive basal cells, and the keratinized epithelium expands horizontally to replace the surrounding normal urothelium. These data suggest that the urothelium consists of multiple cell lineages, that trigone urothelium is closely related to the urothelium covering the rest of the bladder, and that lineage heterogeneity coupled with cell migration/replacement form the cellular basis for urothelial squamous metaplasia.     

Identification and characterisation of seed storage protein transcripts from Lupinus angustifolius

Background  

In legumes, seed storage proteins are important for the developing seedling and are an important source of protein for humans and animals. Lupinus angustifolius (L.), also known as narrow-leaf lupin (NLL) is a grain legume crop that is gaining recognition as a potential human health food as the grain is high in protein and dietary fibre, gluten-free and low in fat and starch.     

Chronic stress and its effects on adrenal cortex apoptosis in pregnant rats

The model of chronic intermittent stress by immobilization during pregnancy may produce alterations in the mechanisms that maintain adrenal gland homeostasis. In earlier investigations using this model, significant variations in plasma prolactin and corticosterone levels, and adrenal gland weights were observed. We hypothesized that chronic stress causes changes in apoptosis in the adrenal glands of pregnant rats. We identified and quantified apoptotic cells in the adrenal cortex and examined their ultrastructural characteristics using transmission electron microscopy. Adrenal glands of pregnant rats at gestation days 12, 17 and 21 were studied for control and experimental (stressed) rats. Immunolabelling techniques, stereological analysis and image quantification of adrenal gland sections were combined to determine differences in apoptosis in the different cell populations of the adrenal cortex. The apoptotic index of the experimental rats showed a significant reduction at gestation day 17, while at days 12 and 21 there were no differences from controls. Moreover, the apoptotic index of the reticular zones in control and experimental animals showed a significant increase compared to the glomerular and fascicular zones at the three gestation times studied. Chronic stress by immobilization reduced the caspase-dependent apoptotic index at gestation day 17, which may be related to variations in plasma concentrations of estrogens and prolactin.     

Interleukin-23 is critical for full-blown expression of a non-autoimmune destructive arthritis and regulates interleukin-17A and RORγt in γδ T cells

Introduction  

Interleukin (IL)-23 is essential for the development of various experimental autoimmune models. However, the role of IL-23 in non-autoimmune experimental arthritis remains unclear. Here, we examined the role of IL-23 in the non-autoimmune antigen-induced arthritis (AIA) model. In addition, the regulatory potential of IL-23 in IL-17A and retinoic acid-related orphan receptor gamma t (RORγt) expression in CD4⁺ and TCRγδ⁺ T cells was evaluated systemically as well as at the site of inflammation.