The abundance and diversity of arbuscular mycorrhizal fungi are linked to the soil chemistry of screes and to slope in the Alpic paleo-endemic Berardia subacaulis

Berardia subacaulis Vill. is a monospecific genus that is endemic to the South-western Alps, where it grows on alpine screes, which are extreme habitats characterized by soil disturbance and limiting growth conditions. Root colonization by arbuscular mycorrhizal fungi (AMF) is presumably of great importance in these environments, because of its positive effect on plant nutrition and stress tolerance, as well as on structuring the soil. However, there is currently a lack of information on this topic. In this paper, we tested which soil characteristics and biotic factors could contribute to determining the abundance and community composition of AMF in the roots of B. subacaulis, which had previously been found to be mycorrhizal. For such a reason, the influence of soil properties and environmental factors on AMF abundance and community composition in the roots of B. subacaulis, sampled on three different scree slopes, were analysed through microscopic and molecular analysis. The results have shown that the AMF community of Berardia roots was dominated by Glomeraceae, and included a core of AMF taxa, common to all three scree slopes. The vegetation coverage and dark septate endophytes were not related to the AMF colonization percentage and plant community did not influence the root AMF composition. The abundance of AMF in the roots was related to some chemical (available extractable calcium and potassium) and physical (cation exchange capacity, electrical conductivity and field capacity) properties of the soil, thus suggesting an effect of AMF on improving the soil quality. The non-metric multidimensional scaling (NMDS) ordination of the AMF community composition showed that the diversity of AMF in the various sites was influenced not only by the soil quality, but also by the slope. Therefore, the slope-induced physical disturbance of alpine screes may contribute to the selection of disturbance-tolerant AMF taxa, which in turn may lead to different plant-fungus assemblages.

Insulin modulates PC-1 processing and recruitment in cultured human cells

We evaluated whether insulin signaling modulates plasma cell glycoprotein (PC-1) plasma membrane recruitment, posttranslational processing, and gene expression in human cultured cell lines. Insulin induced a fourfold increase (P < 0.01) of membrane PC-1 expression by rapid and sensitive mechanism(s). This effect was reduced (P < 0.05-0.01) by inhibition of phosphatidylinositol 3-kinase (200 nmol/l wortmannin) and S6 kinase (50 nmol/l rapamycin) activities and intracellular trafficking (50 micromol/l monensin) and was not accompanied by PC-1 gene expression changes. Moreover, at Western blot, insulin elicited the appearance, in both plasma membrane and cytosol, of a PC-1-related 146-kDa band (in addition to bands of 163, 117, 106, and 97 kDa observed also in absence of insulin) that was sensitive to endoglycosidase H. Finally, inhibition of PC-1 translocation to plasma membrane, by wortmannin pretreatment, increases insulin-stimulated receptor autophosphorylation. Our data indicate that insulin stimulates PC-1 posttranslational processing and translocation to the plasma membrane, which in turn impairs insulin receptor signaling. Bidirectional cross talk between insulin and PC-1, therefore, takes place, which may be part of the hormone self-desensitization mechanism.

Retinoids in breast cancer prevention and treatment. A review of the literature

During the last three decades, research focused on cancer treatment has led to the development of many cytotoxic agents. Despite the fact that these efforts have significantly improved the prognosis of certain malignancies such as some lymphomas, leukemias and testicular carcinomas, other tumors such as ovarian, lung and metastatic breast cancer are still associated with a poor prognosis. An innovative approach has recently emerged, thanks to a better understanding of tumor cell biology and many efforts are aimed at finding compounds capable of restoring a more differentiated phenotype to tumor cells, thereby reducing the tumor's aggressiveness and ultimately reverting it to its normal counterpart [1, 2]. Retinoids are the prototype of this new therapeutical approach called "differentiation therapy".

Uterine malformations and pregnancy losses: is cervical cerclage effective?

For many years, we and others have reported the efficacy of cervical cerclage in the prevention of miscarriage in patients with uterine malformations. In this paper the experience of 275 cases collected between 1978 and 1998 is reported. Our data indicate that cervical cerclage is effective in preventing miscarriages, prevalently in those pregnancies bearing uterine malformations with simultaneous cervical incompetence.

Evidence of an immunologic mechanism behind the therapeutical effects of arsenic trioxide (As(2)O(3)) on myeloma cells

Exposure of RPMI 8226, Karpas 707 and U266 human myeloma-like lines to low doses of As(2)O(3) was followed by a marked increase in lymphokine activated killers (LAK)-mediated killing and up- modulation of CD38 and CD54, two molecules involved in cell-cell interactions. Moreover, simultaneous exposure of effectors and targets to As(2)O(3) yielded the most effective condition for lysis. The expression of CD31 (CD38 ligand) and CD11a (CD54 ligand) was also up-regulated by LAK, suggesting that increased adhesion was responsible for the improved killing. Similar results were obtained using freshly isolated myeloma cells. These findings indicate that As(2)O(3) may be useful to boost the immune system against myelomas.

Hormonal modulation of GM-CSF receptor alpha-chain in in vitro models of endometrial cancer

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that stimulates the proliferation and differentiation of bone marrow progenitors. Moreover, the presence and activity of GM-CSF and its receptor (GM-CSF-r) has been documented on tissues and cell lines of a non-hemopoietic origin. In this paper we studied the expression and putative role of GM-CSF and GM-CSF-r in endometrial cancer. The modulation of GM-CSF-r alpha-chain upon progesterone treatment suggests a role for GM-CSF and its receptor in the pathogenesis and development of endometrial cancer.

All-trans retinoic acid inhibits the growth of breast cancer cells by up-regulating ICAM-1 expression

All-trans retinoic acid (ATRA) is currently used in clinical trials for breast cancer, in virtue of its ability to inhibit cell growth and to promote cell differentiation. Elucidation of the molecular mechanism(s) underlying the pleiotropic pharmacological activity of ATRA is of fundamental relevance for an effective use of the compound in clinics. This paper reports on the effects of ATRA treatment on the cell surface expression of a panel of adhesion molecules known to regulate the interactions between the effectors of the immune system and tumor targets. Results indicate that breast cancer (BC) cell lines exposed to ATRA selectively up-modulate the surface expression of ICAM-1/CD54, a molecule regulating cell/cell contacts. Such effect could be reproduced in all the BC cell lines analyzed, independently of their hormone receptor status, indicating that estrogens and progesterone are irrelevant in this process. The regulatory effects on ICAM-1 expression are time- and dose-dependent and reversible. Moreover, other differentiating and proliferating agents comparatively tested, e.g. dimethyl sulfoxide, estradiol or dexamethas one, are ineffective, indicating that ICAM-1 up-modulation is uniquely featured by ATRA. A second observation is that ATRA treated cells are, only apparently, less sensitive to lysis by lymphocytes activated by IL-2, as determined by means of a standard 51Cr release assay. In fact, notwithstanding this effect, a marked reduction in the ability to form colonies was highlighted in ATRA treated versus control lines after incubation with LAK. Finally, the clonogenic killing effect could be reversed using anti-CD54 mAbs as blocking tools, indicating that ICAM-1 plays a key role in the phenomena.