Enhanced resistance to Salmonella enterica serovar Typhimurium infection in mice after coumarin treatment

Coumarin and its derivatives are naturally occurring substances with multiple biological activities. Here we demonstrate that prophylactic peroral administration of coumarin or 7-hydroxycoumarin (7-OHC) enhances resistance to subsequent lethal Salmonella enterica Serovar Typhimurium infection in mice. 7-OHC decreased bacterial load in liver and spleen, and enhanced phagocytosis and bacterial killing by macrophages when applied in vitro and in vivo. 7-OHC treatment induced significant NO release in peritoneal macrophage cultures. The observed protective effect correlated with the induction of Th1-associated cytokines, such as IL-12, IFN-gamma, and TNF-alpha. These data demonstrate a clear immunomodulatory potential of coumarins which might have important therapeutic implications to enhance resistance to infection.     

Combining tree-ring analyses on stems and coarse roots to study the growth dynamics of forest trees: a case study on Norway spruce (Picea abies [L.] H. Karst)

We show the potential of a new method combining tree-ring analyses on stems and on coarse roots of individual trees in order to advance the understanding of growth dynamics in forest trees. To this end, we studied the root–shoot allometry of trees and its dependence on site conditions. Along a gradient in water supply in Southern Germany from dry to moist sites we selected 43 Norway spruce trees (Picea abies [L.] H. Karst.) aged 65–100 years. Increment cores were taken from stem and main roots revealing aboveground and belowground growth course over the last 34 years. Annual growth rates in roots and stems and their allometric relationships were applied as surrogate variables for tree resource allocation to aboveground and belowground organs. The mean sensitivities of both stem and root chronologies were found to be site-specific, and increased from the moist through the dry sites. No temporal offset between aboveground and belowground growth reactions to climate conditions was found in Norway spruce at any of the sites. These results suggest that the root–shoot allometry depends on the specific site conditions only at the driest site, following the optimal biomass partitioning theory (the more restricted the water supply, the more organic matter allocation into the belowground organs).     

Induction of apoptosis by electrotransfer of positively charged proteins as Cytochrome C and Histone H1 into cells

Cytochrome C (Cyt. C) is a mitochondrial protein inducing apoptosis when it is accumulated in the cytosol by a currently unknown mechanism, but regulated by the bcl-2 family of proteins. The linker Histone H1 is another basic protein with highly conservative structure, composition, and equal molecular weight, not changed during the evolution. An attempt was made to understand better the apoptotic processes by electroloading of leukemic cells, such as K562, HL-60, and SKW3, and human lymphocytes with positively charged proteins, such as Cyt. C, Histone H1, and methylated BSA albumin (mBSA). The triggering apoptotic processes followed by MTT test, FACS analysis, and DNA fragmentation after the electrotransfer of these proteins into the cells were observed. Histone H1 and mBSA induce the release of Cyt. C from rat liver mitochondria. Cytochrome C release was higher when mitochondria were in "high-energy" state. It is supposed that release of Cyt. C from mitochondria is due to the mechanical rupture of the outer mitochondrial membrane, rich in negatively charged groups, predominately due to cardiolipin. The reason for the morphological rupture of the outer mitochondial membrane could be the rigidification and segregation of the membrane and the destroyed membrane asymmetries of both monolayers in the presence of positively charged proteins at higher linear charges such as Histone H1. We suggested that Histone H1, at a given moment of activated signaling for apoptosis, could be not transported to the nucleus and could lead to the release of Cyt. C from the mitochondria in the cytoplasm. It is temping to speculate that Histone H1 has other physiological extranuclear functions involved in apoptosis.     

Absence of foramen spinosum and abnormal middle meningeal artery in cranial series

In comparative and evolutionary aspects in humans, the middle meningeal artery enters the cranium through the foramen spinosum, whereas in great apes the middle meningeal artery can enter the cranium through foramen spinosum, through foramen ovale or through petrosphenoid fissure. Generally, in nonhuman primates the anterior meningeal system is associated with the ophthalmic branch of the internal carotid artery. The vessels joining the two systems pass through the additional channels: the superior orbital fissure or through the cranio-orbital foramen. In anatomically modern humans, the absence of foramen spinosum involves abnormal development and course of the middle meningeal artery and it is usually accompanied with replacement of the conventional middle meningeal artery with such, arising from the ophthalmic artery system. In these cases the middle meningeal artery most often enters the middle cranial fossa through the superior orbital fissure and rarely through the meningo-orbital foramen. All skulls, investigated in the present study, belonged to adult individuals of both sexes, conditionally grouped into three cranial series--contemporary male, medieval male, and medieval female series. The absence of foramen spinosum was established only among the medieval male and female series--in 1 (0.70%) male and in 1 (0.72%) female skull on the right side and in 3 (2.13%) female skulls on the left side. In 1 (0.72%) female skull, a small atypically located foramen spinosum was established on the right side. In all of the described cases, the intracranial meningeal grooves started from the lateral edge of the superior orbital fissure and probably reflect the ophthalmic origin of the middle meningeal artery.     

Requirement of Signal Peptidase ComC and Thiol-Disulfide Oxidoreductase DsbA for Optimal Cell Surface Display of Pseudopilin ComGC in Staphylococcus aureus

Staphylococcus aureus is an important Gram-positive bacterial pathogen producing many secreted and cell surface-localized virulence factors. Here we report that the staphylococcal thiol-disulfide oxidoreductase DsbA is essential for stable biogenesis of the ComGC pseudopilin. The signal peptidase ComC is indispensable for ComGC maturation and optimal cell surface exposure.     

Cks1 is required for tumor cell proliferation but not sufficient to induce hematopoietic malignancies

The Cks1 component of the SCF(Skp2) complex is necessary for p27(Kip1) ubiquitylation and degradation. Cks1 expression is elevated in various B cell malignancies including Burkitt lymphoma and multiple myeloma. We have previously shown that loss of Cks1 results in elevated p27(Kip1) levels and delayed tumor development in a mouse model of Myc-induced B cell lymphoma. Surprisingly, loss of Skp2 in the same mouse model also resulted in elevated p27(Kip1) levels but exhibited no impact on tumor onset. This raises the possibility that Cks1 could have other oncogenic activities than suppressing p27(Kip1). To challenge this notion we have targeted overexpression of Cks1 to B cells using a conditional retroviral bone marrow transduction-transplantation system. Despite potent ectopic overexpression, Cks1 was unable to promote B cell hyperproliferation or B cell malignancies, indicating that Cks1 is not oncogenic when overexpressed in B cells. Since Skp2 overexpression can drive T-cell tumorigenesis or other cancers we also widened the quest for oncogenic activity of Cks1 by ubiquitously expressing Cks1 in hematopoetic progenitors. At variance with c-Myc overexpression, which caused acute myeloid leukemia, Cks1 overexpression did not induce myeloproliferation or leukemia. Therefore, despite being associated with a poor prognosis in various malignancies, sole Cks1 expression is insufficient to induce lymphoma or a myeloproliferative disease in vivo.     

Uses and misuses of progress curve analysis in enzyme kinetics

Progress curve analysis is a convenient tool for the characterization of enzyme action: a single reaction mixture provides multiple experimental measured points for continuously varying amounts of substrates and products with exactly the same enzyme and modulator concentrations. The determination of kinetic parameters from the progress curves, however, requires complex mathematical evaluation of the time-course data. Some freely available programs (e.g. FITSIM, DYNAFIT) are widely applied to fit kinetic parameters to user-defined enzymatic mechanisms, but users often overlook the stringent requirements of the analytic procedures for appropriate design of the input experiments. Flaws in the experimental setup result in unreliable parameters with consequent misinterpretation of the biological phenomenon under study. The present commentary suggests some helpful mathematical tools to improve the analytic procedure in order to diagnose major errors in concept and design of kinetic experiments.     

Rapid TLC/GC-MS identification of acetylcholinesterase inhibitors in alkaloid extracts

Alkaloid extracts from 12 plant species of the families Amaryllidaceae, Fumariacae and Papaveraceae were studied with respect to their acetylcholinesterase inhibitory activity and alkaloid patterns. Fifty-three alkaloids were identified by GC-MS, including known acetylcholinesterase (AChE) inhibitors such as galanthamine, epigalanthamine, sanguinine and epinorgalanthamine in extracts of Amaryllidaceae plants and protopine in extracts of Fumariaceae and Papaveraceae plants. The galanthamine-containing extracts of the amaryllidaceous plants were found to be the most active while the extract of Corydalis bulbosa was the most active among the extracts of the tested plants from the Fumariaceae and Papaveraceae plants. TLC bioautographic assay, preparative TLC and GC-MS analysis were combined to identify the active compounds in the studied extracts. Galanthamine was isolated from the known AChE inhibitors in the extracts of Amaryllidaceae plants. Corydaline, bulbocapnine and stylopine were found to be active in the extracts of plant species of the families Fumariaceae and Papaveraceae. Available standards of deshydrocorydaline--a precursor of corydaline, corydaline and stylopine--were tested for AChE inhibitory activity. Deshydrocorydaline and corydaline showed potent inhibitory activity comparable with that of the positive control galanthamine.