Multiple stages of plant root calcification deciphered by chemical and micromorphological analyses

Rhizoliths, that is, roots fossilized by secondary carbonates, have been known for ages and are increasingly used for paleoenvironmental reconstructions. However, knowledge about their formation mechanisms remains limited. This study reports the mineralogical and chemical characterization of rhizoliths at different stages of mineralization and fossilization in the Late Pleistocene loess–paleosol sequence of Nussloch (SW Germany). Scanning electron microscopy coupled with elemental mapping and ¹³C solid‐state nuclear magnetic resonance were used to concomitantly characterize the mineral and organic matter of the rhizoliths. These joint analyses showed for the first time that large rhizoliths are not necessarily remains of single large roots but consist of numerous microrhizoliths as remains of fine roots, formed mainly by calcium carbonates with only low amounts of Mg and Si. They further revealed that the precipitation of secondary carbonates occurs not only around, but also within the plant root and that fossilization leads to the selective preservation of recalcitrant root biopolymers—lignin and suberin. The precipitation of secondary carbonates was observed to occur first around fine roots, the epidermis acting as a first barrier, and then within the root, within the cortex cells, and even sometimes around the phloem and within the xylem. This study suggests that the calcification of plant roots starts during the lifetime of the plant and continues after its death. This has to be systematically investigated to understand the stratigraphic context before using (micro)rhizoliths for paleoenvironmental reconstructions in terrestrial sediments.     

Activation of Notch Signaling Is Required for Cholangiocarcinoma Progression and Is Enhanced by Inactivation of p53 In Vivo

Cholangiocacinoma (CC) is a cancer disease with rising incidence. Notch signaling has been shown to be deregulated in many cancers. However, the role of this signaling pathway in the carcinogenesis of CC is still not fully explored. In this study, we investigated the effects of Notch inhibition by γ-secretase inhibitor IX (GSI IX) in cultured human CC cell lines and we established a transgenic mouse model with liver specific expression of the intracellular domain of Notch (Notch-ICD) and inactivation of tumor suppressor p53. GSI IX treatment effectively impaired cell proliferation, migration, invasion, epithelial to mesenchymal transition and growth of softagar colonies. In vivo overexpression of Notch-ICD together with an inactivation of p53 significantly increased tumor burden and showed CC characteristics. Conclusion: Our study highlights the importance of Notch signaling in the tumorigenesis of CC and demonstrates that additional inactivation of p53 in vivo.     

The effects and mechanism of flavonoid–rePON1 interactions. Structure–activity relationship study

Flavonoids are plant phenolic secondary metabolites that are widely distributed in the human diet. These antioxidants have received much attention because of their neuroprotective, cardioprotective, and chemopreventive actions. While a major focus has been on the flavonoids’ antioxidant properties, there is an emerging view that many of the potential health benefits of flavonoids and their in vivo metabolites are due to modulatory actions in cells through direct interactions with proteins, and not necessarily due to their antioxidant function. This view relies on the observations that flavonoids are present in the circulation at very low concentrations, which are not sufficient to exert effective antioxidant effects. The enzyme paraoxonase 1 (PON1) is associated with high-density lipoprotein (HDL), and is responsible for many of HDLs’ antiatherogenic properties. We previously showed that the flavonoid glabridin binds to rePON1 and affects the enzyme’s 3D structure. This interaction protects the enzyme from inhibition by an atherogenic component of the human carotid plaque. Here, we broadened our study to an investigation of the structure–activity relationships (SARs) of 12 flavonoids from different subclasses with rePON1 using Trp-fluorescence quenching, modeling calculations and Cu²⁺-induced low-density lipoprotein (LDL) oxidation methods. Our findings emphasize the ‘protein-binding’ mechanism by which flavonoids exert their beneficial biological role toward rePON1. Flavonoids’ capacity to interact with the enzyme’s rePON1 hydrophobic groove mostly dictates their pro/antioxidant behavior.     

Fine needle aspiration diagnosis of extraadrenal myelolipoma presenting as a pleural mass. A case report

BACKGROUND: Myelolipoma is a benign tumor composed of mature adipose tissue and hematopoietic cells. Although they are commonly found in adrenal glands, extraadrenal myelolipomas (EMLs) are rare but well documented. They have been found in various sites, including mediastinum, liver, stomach, lungs, pelvis, spleen, retroperitoneum, presacral region and mesentery. EMLs must be distinguished from extramedullary hematopoieses, which are also composed of hematopoietic elements but may lack adipose tissue and are associated with anemia and marked bone marrow hyperplasia. CASE: We describe a case of a pleura-based, extraadrenal myelolipoma in a 53-year-old female with unremarkable bone marrow findings that were initially encountered on fluoroscopy-guided fine needle aspiration (FNA). One year later the mass was removed via open thoracotomy. It showed typical EML features histologically. CONCLUSION: EML manifests on aspiration cytology as a cellular specimen with numerous trilineage hematopoietic cells and a variable proportion of mature adipose cells. To our knowledge, FNA cytology of EML has not been found in this location before. Aspiration biopsy offers a simple and reliable method for the diagnosis of EML in the presence of appropriate clinical settings.     

A biomarker for the identification of cattle fecal pollution in water using the LTIIa toxin gene from enterotoxigenic Escherichia coli

This research describes a method based on PCR to identify cattle fecal pollution in water using a portion of the heat labile toxin IIA (LTIIa) gene from enterotoxigenic Escherichia coli (ETEC). We describe the development of the primers and target. DNA extracts (221) from different animal fecal and human sewage samples were screened and showed no cross-reactivity. Minimum detection limits using centrifugation and filtration methods to concentrate E. coli seeded into stream, ocean, and secondary effluent waters were found to be at femtogram and attogram levels, respectively. Stability of the biomarker in stream, ocean, and secondary effluent waters was 2-4 weeks for all water types. Finally, 33 farm lagoon and waste samples were collected and 31 tested to validate the method; 93% were positive for the LTIIa trait when >1,000 E. coli were screened and 100% positive when >10(5) E. coli were screened. Prevalence of the toxin gene in the E. coli population affected the outcome of the analyses. The cow biomarker can be used in watershed studies to identify cattle waste with great accuracy if the appropriate numbers of E. coli are screened.     

Études stratigraphique,sédimentologique et paléomagnétique des travertins de Kocabaş, Bassin de Denizli,Anatolie, Turquie,contenant des restes fossiles quaternaires

Stratigraphic, sedimentological and paleomagnetic studies were conducted on the travertine from Denizli Basin, near Kocabas village, in the Denizli region in Turkey, following the paleontological discovery in 2002. The stratigraphic and sedimentological studies show at least two main cycles of mass travertine, separated by a fluvial deposit and overlain by a fluvio-lacustrine deposit. These travertines must have formed in environments with strong hydrodynamics (streams or waterfalls) and are preferentially located at breaks of slopes. The paleomagnetic study shows that all the quarry travertine presents reverse magnetic polarity. On the other hand, the detrital fluvio-lacustrine deposit above the travertine presents normal geomagnetic polarity, except at the top, where it is reversed. Given the presence of an archaic Homo erectus skull and Villafranchian paleontological remains in the upper travertine unit, the whole travertine dates from the upper Matuyama, and is more recent than the Olduvai event (1.78 Ma). The normal polarity recorded in the upper fluvio-lacustrine deposit could correspond to the Cobb Mountain excursion, dated to 1.22 Ma.     

Articular chondrocyte aging and endothelin-1

OBJECTIVE: To compare in cell culture endothelin-1 (ET-1) production, receptor density, and effect on macromolecular synthesis by articular chondrocytes (AC). METHODS: AC were isolated from 1-month and 18-month old rats and cultured as monolayers. They were incubated with ET-1 without or with iNOS inhibitors, nitro-L-arginine methyl ester (L-NAME) or guanylate cyclase inhibitor, LY83583 and then [3H]thymidine, 35SO4 and [3H]proline incorporations were measured. The density and affinity for 125I-ET-1 of binding sites, and receptor isotypes were determined. The cells were also treated with interleukin-1beta (IL-1beta) or tumor necrosis factor-alpha (TNF-alpha), and then ET-1 productions measured. As well, the cells were challenged with NOC-5 (nitric oxide donor) or ET-1 and then ET-1 and NO respectively were measured. RESULTS: A concentration-dependent stimulation of DNA, PG, collagen and NO synthesis was obtained when cells were incubated with ET-1 for 24-h. Eighteen-month old chondrocytes incorporated per microg DNA more [3H]thymidine, 35SO4 and [3H]proline but less NO when challenged with ET-1 than the 1-month old cells. However, strong inhibition of this initial stimulation was seen after 48-h. L-NAME and LY83583 enhanced basal-, and ET-1-induced initial stimulation and completely suppressed late (at 48-h to 72-h) ET-1-induced inhibition, suggesting NO was responsible for this inhibitory effect. Eighteen-month old chondrocytes expressed per mug DNA more high affinity receptors of predominantly ET(A) subtype. They also produced more ET-1 but less NO under basal conditions and more ET-1 when challenged with IL-1beta and TNF-alpha. NOC-5 inhibited the production of ET-1. CONCLUSIONS: Eighteen-month old chondrocytes produce more ET-1, possess more ET-1-specific receptors, and increase more DNA, PG and collagen synthesis when challenged during 24-h with ET-1. NO, which suppresses ET-1 production and the production of which is increased by ET-1, seems to account for the late ET-1-induced inhibition of macromolecular synthesis. The possible implication of ET-1 in aging as related to osteoarthritis is discussed.     

Human carotid lesion linoleic acid hydroperoxide inhibits paraoxonase 1 (PON1) activity via reaction with PON1 free sulfhydryl cysteine 284

Paraoxonase 1 (PON1) is an HDL-associated lactonase with antiatherogenic properties. These include dampening the oxidation properties of human carotid lesion lipid extract (LLE), which in turn inactivates the enzyme. The aims of this study were to identify the PON1 inhibitor in LLE and explore the mechanism of inhibition. LLE inhibited both recombinant PON1 and HDL-PON1 lactonase activity in a dose- and time-dependent manner. Addition of antioxidants or electrophiles to LLE did not prevent PON1 inhibition. LLE was unable to inhibit a PON1 mutant lacking Cys284, whereas it did inhibit all other PON1 mutants tested. The inhibitor in the LLE was identified as linoleic acid hydroperoxide (LA-OOH) and inhibition was specific to this hydroperoxide. During its inhibition, PON1 acted like a peroxidase enzyme, reducing LA-OOH to LA-hydroxide via its Cys284. A similar reaction occurred with external thiols, such as DDT or cysteine, which also prevented PON1 inhibition and restored enzyme activity after inhibition. Thus, the antiatherogenic properties of HDL could be, at least in part, related to the sulfhydryl-reducing characteristics of its associated PON1, which are further protected and recycled by the sulfhydryl amino acid cysteine.     

Prostaglandin E2 induces degranulation-independent production of vascular endothelial growth factor by human mast cells

Mast cells accumulate in large numbers at angiogenic sites, where they have been shown to express a number of proangiogenic factors, including vascular endothelial growth factor (VEGF-A). PGE(2) is known to strongly promote angiogenesis and is found in increased levels at sites of chronic inflammation and around solid tumors. The expression pattern of VEGF and the regulation of VEGF-A by PGE(2) were examined in cord blood-derived human mast cells (CBMC). CBMC expressed mRNA for five isoforms of VEGF-A and other members of the VEGF family (VEGF-B, VEGF-C, and VEGF-D) with strong expression of the most potent secretory isoforms. PGE(2) was a very strong inducer of VEGF-A(121/165) production by CBMC and also elevated VEGF-A mRNA expression. The amount of VEGF-A(121/165) protein production induced by PGE(2) was 4-fold greater than that induced by IgE-mediated activation of CBMC. Moreover, the response to PGE(2) as well as to other cAMP-elevating agents such as forskolin and salbutamol was observed under conditions that were not associated with mast cell degranulation. CBMC expressed substantial levels of the EP(2) receptor, but not the EP(4) receptor, when examined by flow cytometry. In contrast to other reported PGE(2)-mediated effects on mast cells, VEGF-A(121/165) production occurred via activation of the EP(2) receptor. These data suggest a role for human mast cells as a potent source of VEGF(121/165) in the absence of degranulation, and may provide new opportunities to regulate angiogenesis at mast cell-rich sites.     

Routine delivery of artemisinin-based combination treatment at fixed health facilities reduces malaria prevalence in Tanzania: an observational study

ABSTRACT: BACKGROUND: Artemisinin-based combination therapy (ACT) has been promoted as a means to reduce malaria transmission due to their ability to kill both asexual blood stages of malaria parasites, which sustain infections over long periods and the immature derived sexual stages responsible for infecting mosquitoes and onward transmission. Early studies reported a temporal association between ACT introduction and reduced malaria transmission in a number of ecological settings. However, these reports have come from areas with low to moderate malaria transmission, been confounded by the presence of other interventions or environmental changes that may have reduced malaria transmission, and have not included a comparison group without ACT. This report presents results from the first large-scale observational study to assess the impact of case management with ACT on population-level measures of malaria endemicity in an area with intense transmission where the benefits of effective infection clearance might be compromised by frequent and repeated re-infection. METHODS: A pre-post observational study with a non-randomized comparison group was conducted at two sites in Tanzania. Both sites used sulphadoxine-pyrimethamine (SP) monotherapy as a first-line anti-malarial from mid-2001 through 2002. In 2003, the ACT, artesunate (AS) coadministered with SP (AS + SP), was introduced in all fixed health facilities in the intervention site, including both public and registered non-governmental facilities. Population-level prevalence of Plasmodium falciparum asexual parasitaemia and gametocytaemia were assessed using light microscopy from samples collected during representative household surveys in 2001, 2002, 2004, 2005 and 2006. FINDINGS: Among 37,309 observations included in the analysis, annual asexual parasitaemia prevalence in persons of all ages ranged from 11% to 28% and gametocytaemia prevalence ranged from <1% to 2% between the two sites and across the five survey years. Amultivariable logistic regression model was fitted to adjust for age, socioeconomic status, bed net use and rainfall. In the presence of consistently high coverage and efficacy of SP monotherapy and AS + SP in the comparison and intervention areas, the introduction of ACT in the intervention site was associated with a modest reduction in the adjusted asexual parasitaemia prevalence of 5 percentage-points or 23% (p < 0.0001) relative to the comparison site. Gametocytaemia prevalence did not differ significantly (p = 0.30). Interpretation The introduction of ACT at fixed health facilities only modestly reduced asexual parasitaemia prevalence. ACT is effective for treatment of uncomplicated malaria and should have substantial public health impact on morbidity and mortality, but is unlikely to reduce malaria transmission substantially in much of sub-Saharan Africa where individuals are rapidly reinfected.