Effect of the α-agonist noradrenaline on total and 45Ca2+ movements in mitochondria of rat liver cells

Ca²⁺ movements triggered by noradrenaline were determined in isolated cells and mitochondria from rat livers. It has been shown that these depend on experimental conditions. In cells incubated in 1.8mm-Ca²⁺, results suggest that noradrenaline mobilizes Ca²⁺ from reticulum before releasing Ca²⁺ from mitochondria.     

Plant neighborhood influences colonization of Brassicaceae by specialist and generalist aphids

A plant's own characteristics, but also those of its neighbors, might have an impact on its probability of being colonized by herbivorous insects. A plant might be less colonized and experience associational resistance when it grows near repellent neighbors. In contrast, it might be more colonized and experience associational susceptibility near attractive neighbors. To date, mechanisms that drive associational defense are not really understood. In order to gain insights into the occurrence of associational resistance versus associational susceptibility under field conditions, we conducted an experiment to determine the influence of neighboring plants on the colonization of a focal plant by aphids. The focal plant was always Brassica oleracea. The neighbors were B. oleracea (control), B. napus, B. nigra, or Solanum lycopersicum, which represent contrasting levels of physical and chemical defenses. The focal plant, B. oleracea, was more colonized by the specialist aphid Brevicoryne brassicae, and experienced associational susceptibility when it was surrounded by B. nigra or B. napus. In contrast, B. oleracea was less colonized by the generalist aphid Myzus persicae, and experienced associational resistance when it was surrounded by S. lycopersicum, B. nigra or B. napus. Neighboring plants had no significant impact on host plant choice by the generalist aphid Macrosiphum euphorbiae. In conclusion, attraction or repulsion of the specialist aphid B. brassicae and the generalist aphid M. persicae by B. nigra, B. napus, and S. lycopersicum resulted in associational susceptibility or associational resistance for B. oleracea.     

Induction of the CD23/nitric oxide pathway in endothelial cells downregulates ICAM-1 expression and decreases cytoadherence of Plasmodium falciparum-infected erythrocytes

Cytoadherence of parasitized red blood cells (PRBCs) to postcapillary venules and cytokine production are clearly involved in the pathogenesis of cerebral malaria. Nitric oxide and TNF-alpha have been proposed as major effector molecules both in protective and physiopathological processes during malaria infections. Nitric oxide production has been shown to be induced by engagement of CD23 antigen. This study aimed to investigate the potential role of the CD23/nitric oxide pathway in the control of the cytoadherence of PRBCs on human endothelial cells. We demonstrate that normal human lung endothelial cells (HLECs) are able to express the low affinity receptor for IgE (Fc in RII/CD23), following cell incubation with interleukin 4 or PRBCs. Ligation of the CD23 antigen by a specific anti-CD23 monoclonal antibody at the cell surface of HLECs was found to induce iNOS mRNA and protein expression, NO release and P. falciparum killing. In addition, the specific CD23-engagement on these cells also induced a significant decrease in ICAM-1 expression, an adhesion molecule implicated in PRBCs cytoadherence. These data not only described for the first time the expression of a CD23 antigen at the cell surface of endothelial cells but also suggest a possible new regulatory mechanisms via the CD23/NO pathway during malaria infection.     

Long-term somatic embryogenesis and maturation of somatic embryos in Hevea brasiliensis

A high frequency of secondary embryogenesis was induced from isolated early cotyledonary-stage somatic embryos of Hevea brasiliensis. A long-term embryogenic line was established by the use of recurrent embryogenesis and maintained for 3 years on hormone-free medium by the transfer of selected proembryogenic masses every 10 days.

The addition of 234 mM sucrose as stress with sucrose and 10⁻⁵ M abscisic acid (ABA) to the culture medium enhanced the maturation of somatic embryos. Under these culture conditions, the embryo population was composed of 45% globular, 18% oblong and 37% torpedo-stage embryos. These somatic embryos had well-formed tissue structure, a well-defined epidermis, protein storage bodies, and a high accumulation of starch. The triglyceride content was five times as high in the torpedo-stage embryos that developed on medium supplemented with 234 mM sucrose and 10⁻⁵ M ABA as in embryos obtained on basal medium with 58 mM sucrose.     

Leaf morphology and anatomy of Manilkara Adans. (Sapotaceae) from northeastern Brazil

Aiming to complement the group’s taxonomy, the objective of this work is to describe and characterise, searching for morpho-anatomical patterns, the leaf anatomy of the Manilkara species occurring in the northeast region of Brazil. The leaves of all Manilkara species were analysed, using herbaria specimens and collections made in the field by the authors. The characterisation of the leaf blades was performed according to the usual protocols in vegetal anatomy. As diagnosed by anatomical characters, the Manilkara Adans. genus presents petioles with a thick cuticle, a uniseriate epidermis, a sclerenchymatous sheath involving the vascular bundle, and laticifers on the cortical and medullar regions. The anatomical data increase the M. elata and M. huberi synonymisation and show the importance of the anatomy as a complementary tool to the taxonomy based on external morphology.     

Evaluation of Probiotic Potential of Bacteriocinogenic Lactic Acid Bacteria Strains Isolated from Meat Products

In this study, the probiotic potential of five bacteriocin-producing lactic acid bacteria (LAB) strains, isolated from meat products, was investigated. They were presumptively identified as Lactococcus lactis subsp. cremoris CTC 204 and CTC 483, L. lactis subsp. hordinae CTC 484, and Lactobacillus plantarum CTC 368 and CTC 469 according to morphological, biochemical, and physiological characteristics. Analysis of genetic variability (random amplified polymorphic (RAPD)-PCR) and whole-cell proteins (SDS-PAGE) revealed similarity between Lactobacillus strains and variability among Lactococcus strains. The evaluation of the probiotic potential showed that the five LAB strains were tolerant to pH 2.0, and only strain CTC 469 was tolerant to the lowest concentration of the bile salts evaluated (0.1%). All strains showed survival or growth ability at 4, 25, and 37 °C, and tolerance at ??20 °C. Although strain CTC 204 in TSB Broth supplemented with MgSO₄ showed the highest intensity of biofilm production, this compound was produced by all of them. The safety assessment showed that no thermonuclease, hemolytic, or gelatinase activities were detected. All strains were resistant to erythromycin and sensitive to amoxicillin and phenoxymethylpenicillin; furthermore, CTC 204 was resistant to chloramphenicol, CTC 368 and CTC 469 to chloramphenicol and vancomycin, CTC 483 to tetracycline and vancomycin, and CTC 484 to clindamycin and chloramphenicol. The evaluated strains showed biogenic amine production; the lowest levels were produced by CTC 204 and CTC 368 strains. It was concluded that CTC 204 and CTC 368 strains have the greatest potential for becoming probiotics.     

Design and multi-step synthesis of chalcone-polyamine conjugates as potent antiproliferative agents

The aim of this study is to synthesize chalcone-polyamine conjugates in order to enhance bioavailability and selectivity of chalcone core towards cancer cells, using polyamine-based vectors. 3-hydroxy-3′,4,4′,5′-tetramethoxychalcone (1) and 3′,4,4′,5′-tetramethoxychalcone (2) were selected as parent chalcones since they were found to be efficient anti-proliferative agents on various cancer cells. A series of ten chalcone-polyamine conjugates was obtained by reacting carboxychalcones with different polyamine tails. Chalcones 1 and 2 showed a strong cytotoxic activity against two prostatic cancer (PC-3 and DU-145) and two colorectal cancer (HT-29 and HCT-116) cell lines. Then, chalcone-spermine conjugates 7d and 8d were shown to be the most active of the series and could be considered as promising compounds for colon and prostatic cancer adjuvant therapy.     

Immunochemical analysis of the distribution of the new ovary maturating neurohormone during development of the African locust,Locusta migratoria

Summary Following our prior identification of a gonadotropic neurohormone isolated from the neurosecretory lobe of the corpora cardiaca of the African locust, we have raised a polyclonal antiserum against this new molecule. In the present paper, we characterize this antiserum using enzyme-linked immunosorbent assay and Western blotting. The latter procedure reveals that the immune serum specifically recognizes the neurohormone, which we have termed ovary maturating parsin. Immunohistochemistry, enzyme-linked immunosorbent assay and Western blotting were used to analyze the distribution of this gonadotropic neurohormone throughout the central nervous system during development. It is produced only by the type-B neurosecretory cells of the pars intercerebralis-corpora cardiaca system and is present both in males and females throughout life from embryo to adult. This permanent expression suggests that the neurohormone may have functions other than its primary direct gonadotropic role in females.     

The Effect of CCC and Amo-1618 on Growth, Catalase, Peroxidase and Indoleacetic Acid Oxidase Activity of Young Barley Seedlings

Barley seedlings were grown in darkness on filter paper saturated with phosphate buffer or CCC and Amo-1618 buffered solutions. The effects of CCC and Amo-1618 on growth, catalase, peroxidase and lAA-oxidase were studied on coleoptile and primary leaves. Both growth-retarding chemicals cause an inhibition of growth, Amo-1618 being more effective than CCC. They have no effect on catalase activity. Increasing concentrations of CCC and Amo-1618 progressively stimulate peroxidase and IAA-oxidase activities (Amo-1618 more than CCC). The enzymatic activity in short-treated plants is higher than in the corresponding control plants of the same height. It is proposed that CCC and Amo-1618 exert their effect on the growth of barley by acting on auxin catabolism.