Gastrokine-2 (GKN2) is a secretory peptide of human gastric surface mucous cells (SMCs). It forms disulfide-linked heterodimers with the trefoil factor family (TFF) peptide TFF1. Binding with TFF2 was also reported. Antral SMCs differ from those of the corpus by their TFF3 expression. The aim of this study was to localize GKN2 expression along the antral gland axis, to characterize the continuous regeneration of antral glands, and to investigate the interactions of GKN2 with TFF1, TFF2 and mucins. Methods: The spatial expression of GKN1, GKN2, TFF1-3, MUC5AC and MUC6 was determined using laser microdissection and RT-PCR analysis. Furthermore, antral extracts were separated by gel chromatography and the association of GKN2 with TFF1, TFF2, and mucins was investigated. Results: Differential GKN2 expression was localized along the rostro-caudal axis of the stomach. Laser microdissection revealed characteristic differential expression profiles of GKN1, GKN2, TFF1-3, MUC5AC and MUC6 along the antral gland axis. Both GKN2 and TFF1 were expressed in superficial SMCs. Surprisingly, the TFF1-GKN2 heterodimer did not associate with the mucin fraction; whereas TFF2 showed exclusive association with mucins. Conclusions: Maturation of antral SMCs occurs stepwise via trans-differentiation of TFF3 expressing progenitor cells. The TFF1-GKN2 heterodimer and TFF2 differ characteristically by their binding to gastric mucins. This points to different physiological functions of TFF1 and TFF2, the latter maybe acting as a “link peptide” for stabilization of the gastric mucus.

TFF3 is a member of the trefoil factor family (TFF) peptides, which enhance the surface integrity of mucous epithelia, and is typically secreted by intestinal goblet cells together with the mucin MUC2. Reports of the expression of TFF3 within the normal human stomach are contradictory and the precise localisation of TFF3 is unknown. We have mapped the human gastric mucosa by reverse transcription/polymerase chain reaction and Western blot analysis and by immunohistochemistry. Small amounts of TFF3 were detectable in the oxyntic mucosa of the corpus, whereas TFF3 synthesis increased sharply distal to the corpus-antrum transitional zone. TFF3 secretion was demonstrated in the antrum, the pyloric region and the proximal duodenum. High TFF1 levels were present in all regions of the gastric mucosa including the corpus, whereas the proximal duodenum was nearly devoid of TFF1. Immunohistochemistry localised TFF3 to antral and pyloric surface mucous cells. In the antrum, an increasing concentration gradient was found towards cells deeper in the isthmus. TFF1 was confined to superficial pit cells in the antrum. TFF3 was also present in specific layers of the laminated mucous gel of the antral and pyloric regions and variable concentrations of TFF3 (2-62 nmol/l) were measured in gastric juice. Here, a probably N-terminally shortened variant is present that forms disulphide-linked dimers. Thus, TFF3 is a typical secretory peptide of the normal human antral and pyloric gastric mucosa and has a gastric expression pattern different from that of TFF1 and TFF2. TFF3 might therefore have important physiological functions in the stomach, e.g. as a luminal surveillance peptide maintaining particularly the integrity of the antral and pyloric mucosa.

13Enhanced reductive dehalogenation is an attractive treatment technology for in situ 14 remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is 15 an acid-forming process with hydrochloric acid and also organic acids from fermenta-16 tion of the electron donors typically building up in the source zone during remedia-17 tion. This can lead to groundwater acidification thereby inhibiting the activity of deha-18 logenating microorganisms. Where the soils' natural buffering capacity is likely to be 19 exceeded, the addition of an external source of alkalinity is needed to ensure sustained 20 dehalogenation. To assist in the design of bioremediation systems, an abiotic geo-21 chemical model was developed to provide insight into the processes influencing the 22 groundwater acidity as dehalogenation proceeds, and to predict the amount of bicar-23 bonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., 24 > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water 25 chemistry, electron donor, alternative terminal electron-accepting processes, gas re-26 lease and soil mineralogy. While calcite and iron oxides were shown to be the key 27 minerals influencing the soil's buffering capacity, for the extensive dehalogenation 28 likely to occur in a DNAPL source zone, significant bicarbonate addition may be ne-29 cessary even in soils that are naturally well buffered. Results indicated that the bicar-30 bonate requirement strongly depends on the electron donor used and availability of 31 competing electron acceptors (e.g., sulfate, iron(III)). Based on understanding gained 32 from this model, a simplified model was developed for calculating a preliminary de-33 sign estimate of the bicarbonate addition required to control the pH for user-specified 34 operating conditions. 35

Asthma is a chronic inflammatory disease of the airways that is accompanied by goblet cell metaplasia and mucus hypersecretion. Trefoil factor family (TFF) peptides represent major secretory products of the respiratory tract and are synthesized together with mucins. In the murine lung, TFF2 is mainly expressed, whereas TFF1 transcripts represent only a minor species. TFF peptides are well known for their motogenic and anti-apoptotic effects, and they modulate the inflammatory response of bronchial epithelial cells. Here, an established mouse model of asthma was investigated (i.e., exposure to Aspergillus fumigatus [AF] antigens). RT-PCR analysis of lung tissue showed elevated levels particularly of TFF1 transcripts in AF-sensitized/challenged animals. In contrast, transcripts encoding Clara cell secretory protein (CCSP/CC10) were strongly diminished in these animals. For comparison, the expression of the goblet cell secretory granule marker mCLCA3/Gob-5, the mucins Muc1-Muc6 and Muc19, and the secretoglobins ScgB3A1 and ScgB3A2, as well as the mammalian ependymin-related gene MERP2, were monitored. Immunohistochemistry localized TFF1 mainly in cells with a mixed phenotype (e.g., TFF1-positive cells stain with the lectin wheat germ agglutinin (WGA), which recognizes mucins characteristic of goblet cells). In addition, these cells express CCSP/CC10, a Clara cell marker. When compared with mucins or CCSP/CC10, TFF1 was stored in a different population of secretory granules localized at the more basolateral portion of these cells. Thus, the results presented indicate for the first time that allergen exposure leads to the trans-differentiation of Clara cells toward a TFF1-expressing mucous phenotype.