Cyclic changes in salivary lactate dehydrogenase, peroxidase and leucine aminopeptidase during menstrual cycle

Salivary lactate dehydrogenase (LDH), peroxidase (Px) and leucine aminopeptidase (LAP) activities were scanned in both normally ovulating and anovulating women during entire menstrual cycle. In ovulating women, all the three enzymes exhibited significant increase in the activity on or before the onset of ovulation which was monitored by the shift of the basal body temperature (BBT) as well as the ferning pattern of the cervical mucus. The peak maximum at the midcycle was several times higher than the previous day value in all the six normal women. In anovulatory women, no such remarkable change in the enzyme activities was found throughout the cycle. Salivary LDH and LAP showed peak at the midcycle and at the same time required short time for assay, so the present results are strongly suggestive that the determination of salivary enzyme content may be a convenient method for detecting the day of ovulation.     

Increased carcinogenic potential of myeloid tumor cells induced by aberrant TGF-beta1-signaling and upregulation of cathepsin B

The TGF-beta signaling pathways are implicated in cancer. Cysteine cathepsins can contribute to the carcinogenic potential of tumor cells. The aim of this study was to investigate the regulation of cysteine cathepsin expression by TGF-beta1 and the functional implications in tumor cells. We found an upregulation of cathepsin B (CathB, 2- to 5-fold) in different myeloid tumor cells (THP-1, MonoMac-1, MonoMac-6) after incubation with TGF-beta1. No upregulation was found in monocytes, and there was suppression of CathB expression in epithelial tumor cells (A549). Increased cathepsin B activity led to enhanced carcinogenic potential, which was reflected by increased migration and invasion of the cells and resistance to inhibitor-induced apoptosis. Analysis of the TGF-beta signaling pathways showed no alterations in TGF-beta/BMP receptor expression or SMAD2/3 phosphorylation, and no influence of MAP kinase pathways. However, a reduction in SMAD1 expression was detected. The lack of BMP action on cysteine cathepsin expression in myeloid tumor cells, but not in epithelial tumor cells, suggests a defect in the Smad1/Smad5 pathway. We located a related TGF-beta1-responsive element within the first intron of the CathB gene. In conclusion, alterations in the TGF-beta1 signaling pathway lead to upregulation of CathB, which contributes to the carcinogenic potential of tumor cells.     

Leucine aminopeptidase and exsheathing activity in preparations from Haemonchus contortus

Rogers W.P. and Brooks F. 1978. Leucine aminopeptidase and exsheathing activity in preparations from Haemonchus contortus. International Journal for Parasitology 8: 449–452. Exsheathing activity relative to leucine aminopeptidase activity (LAP) was greater in exsheathing fluid of infective juveniles of Haemonchus contortus than extracts of homogenates of the same organism. In both preparations the biological and enzyme activities were precipitated with acetone 20 v/v and ammonium sulphate, 40% saturation. Broad peaks of exsheathing and LAP activities obtained by sucrose density-gradient centrifugation and on Sephadex G150 overlapped but the peak of biological activity was always found on the low mol. wt. side of the LAP peak. LAP in exsheathing fluid was separated into two sharp peaks in polyacrylamide gradient-pore electrophoresis. In four experiments the major peak gave a mol. wt. within the limits 345,000–354,500. A minor peak was obtained at 1,800,000. Exsheathing activity remained broadly distributed but fell mostly on the low mol. wt. side of the major LAP peak.It is concluded that LAP cannot be the sole agent involved in exsheathment a lipase may be necessary to expose the substrate attacked by LAP.     

Developmental Regulation of Enzymes of Indole Alkaloid Biosynthesis in Catharanthus roseus

Developing seedlings of Catharanthus roseus were analyzed for appearance of tryptophan decarboxylase (TDC), strictosidine synthase (SS), N-methyltransferase (NMT) and O-acetyltransferase (DAT) enzyme activities. SS enzyme activity appeared early after germination and was present throughout most of the developmental study. TDC activity was highly regulated and peaked over a 48 hour period achieving a maximum by day of 5 of seedling development. Both TDC and SS were present in all tissues of the seedling. NMT and DAT enzyme activities were induced after TDC and SS had peaked and these activities could only be found in hypocotyls and cotyledons. TDC, SS, and NMT did not require light for induction whereas DAT enzyme activity was increased approximately 10-fold after light treatment of dark grown seedlings.     

Cathepsin D non-proteolytically induces proliferation and migration in human omental microvascular endothelial cells via activation of the ERK1/2 and PI3K/AKT pathways

Epithelial ovarian cancer (EOC) frequently metastasises to the omentum, a process that requires pro-angiogenic activation of human omental microvascular endothelial cells (HOMECs) by tumour-secreted factors. We have previously shown that ovarian cancer cells secrete a range of factors that induce pro-angiogenic responses e.g. migration, in HOMECs including the lysosomal protease cathepsin D (CathD). However, the cellular mechanism by which CathD induces these cellular responses is not understood. The aim of this study was to further examine the pro-angiogenic effects of CathD in HOMECs i.e. proliferation and migration, to investigate whether these effects are dependent on CathD catalytic activity and to delineate the intracellular signalling kinases activated by CathD. We report, for the first time, that CathD significantly increases HOMEC proliferation and migration via a non-proteolytic mechanism resulting in activation of ERK1/2 and AKT. These data suggest that EOC cancer secreted CathD acts as an extracellular ligand and may play an important pro-angiogenic, and thus pro-metastatic, role by activating the omental microvasculature during EOC metastasis to the omentum.     

Fasting and refeeding cause rapid changes in intestinal tissue mass and digestive enzyme capacities of Atlantic salmon (Salmo salar L.)

Fasting and refeeding effects on gastrointestinal morphology and digestive enzyme activities of Atlantic salmon, held in tanks of seawater at 9 degrees C and 31 per thousand salinity, were addressed in two trials. Trial 1: Fish (mean body mass 1190 g) were fasted for 40 days and intestines sampled at day 0, 2, 4, 11, 19 and 40. Trial 2: Fish (1334 g), fasted for 50 days, were refed and sampled at day 0, 3 and 7. Mass, length, protein, and maltase, lactase, and leucine aminopeptidase (LAP) activities were analyzed for stomach (ST), pyloric caeca (PC), proximal (PI), mid (MI), and distal intestine (DI). PC contributed 50% of gastrointestinal mass and 75% of enzyme capacity. Fasting decreased mass and enzyme capacities by 20-50% within two days, and 40-75% after 40 days. In PC, specific brush border membrane (BBM) maltase activity decreased whereas BBM LAP increased during fasting. Upon refeeding, enzyme capacities were mostly regenerated after one week. The results suggest that refeeding should start slowly with about 25% of estimated feed requirement during the first 3 days, but may then be stepped up rapidly. Investigations of digestive processes of fed fish should only be performed when intestines are feed-filled to avoid bias due to effects of fasting.