Biological and Chemical Characterization of Musa paradisiaca Leachate.

There is a growing demand for molecules of natural origin for biocontrol and biostimulation, given the current trend away from synthetic chemical products. Leachates extracted from plantain stems were obtained after biodegradation of the plant material. To characterize the leachate, quantitative determinations of nitrogen, carbon, phosphorus, and cations (K+, Ca2+, Mg2+, Na+), Q2/4, Q2/6, and Q4/6 absorbance ratios, and metabolomic analysis were carried out. The potential role of plantain leachates as fungicide, elicitor of plant defense, and/or plant biostimulant was evaluated by agar well diffusion method, phenotypic, molecular, and imaging approaches. The plant extracts induced a slight inhibition of fungal growth of an aggressive strain of Colletotrichum gloeosporioides, which causes anthracnose. Organic compounds such as cinnamic, ellagic, quinic, and fulvic acids and indole alkaloid such as ellipticine, along with some minerals such as potassium, calcium, and phosphorus, may be responsible for the inhibition of fungal growth. In addition, jasmonic, benzoic, and salicylic acids, which are known to play a role in plant defense and as biostimulants in tomato, were detected in leachate extract. Indeed, foliar application of banana leachate induced overexpression of LOXD, PPOD, and Worky70-80 genes, which are involved in phenylpropanoid metabolism, jasmonic acid biosynthesis, and salicylic acid metabolism, respectively. Leachate also activated root growth in tomato seedlings. However, the main impact of the leachate was observed on mature plants, where it caused a reduction in leaf area and fresh weight, the remodeling of stem cell wall glycopolymers, and an increase in the expression of proline dehydrogenase.

Ultrastructural Immunolocalization of Arabinogalactan Protein, Pectin and Hemicellulose Epitopes Through Anther Development in Brassica napus.

In this work, we performed an extensive and detailed analysis of the changes in cell wall composition during Brassica napus anther development. We used immunogold labeling to study the spatial and temporal patterns of the composition and distribution of different arabinogalactan protein (AGP), pectin, xyloglucan and xylan epitopes in high-pressure-frozen/freeze-substituted anthers, quantifying and comparing their relative levels in the different anther tissues and developmental stages. We used the following monoclonal antibodies: JIM13, JIM8, JIM14 and JIM16 for AGPs, LM5, LM6, JIM7, JIM5 and LM7 for pectins, CCRC-M1, CCRC-M89 and LM15 for xyloglucan, and LM11 for xylan. Each cell wall epitope showed a characteristic temporal and spatial labeling pattern. Microspore, pollen and tapetal cells showed similar patterns for each epitope, whereas the outermost anther layers (epidermis, endothecium and middle layers) presented remarkably different patterns. Our results suggested that AGPs, pectins, xyloglucan and xylan have specific roles during anther development. The AGP epitopes studied appeared to belong to AGPs specifically involved in microspore differentiation, and contributed first by the tapetum and then, upon tapetal dismantling, by the endothecium and middle layers. In contrast, the changes in pectin and hemicellulose epitopes suggested a specific role in anther dehiscence, facilitating anther wall weakening and rupture. The distribution of the different cell wall constituents is regulated in a tissue- and stage-specific manner, which seems directly related to the role of each tissue at each stage.

Activity of ibrutinib in mantle cell lymphoma patients with central nervous system relapse.

The risk of central nervous system (CNS) dissemination in mantle cell lymphoma (MCL) is low and occurs late in the course of the disease. However, prognosis in such cases remains extremely poor despite high-dose antimetabolite chemotherapy. Among novel drugs used to treat relapsing MCL patients, ibrutinib, an oral inhibitor of Bruton tyrosine kinase, shows great promise. Here we report the clinical observation of 3 MCL patients with symptomatic CNS relapse treated with single-agent ibrutinib. All 3 patients had dramatic and rapid responses with almost immediate recovery from symptoms. We also confirmed that ibrutinib crosses the blood-brain barrier with parallel pharmacokinetic analyses in plasma and cerebrospinal fluid using a validated LC-MS/MS method. All responses were ongoing after 2 months to 1 year of follow-up.

ARAD proteins associated with pectic Arabinan biosynthesis form complexes when transiently overexpressed in planta.

Glycosyltransferase complexes are known to be involved in plant cell wall biosynthesis, as for example in cellulose. It is not known to what extent such complexes are involved in biosynthesis of pectin as well. To address this question, work was initiated on ARAD1 (ARABINAN DEFICIENT 1) and its close homolog ARAD2 of glycosyltransferase family GT47. Using bimolecular fluorescence complementation, Förster resonance energy transfer and non-reducing gel electrophoresis, we show that ARAD1 and ARAD2 are localized in the same Golgi compartment and form homo-and heterodimeric intermolecular dimers when expressed transiently in Nicotiana benthamiana. Biochemical analysis of arad2 cell wall or fractions hereof showed no difference in the monosaccharide composition, when compared with wild type. The double mutant arad1 arad2 had an arad1 cell wall phenotype and overexpression of ARAD2 did not complement the arad1 phenotype, indicating that ARAD1 and ARAD2 are not redundant enzymes. To investigate the cell wall structure of the mutants in detail, immunohistochemical analyses were carried out on arad1, arad2 and arad1 arad2 using the arabinan-specific monoclonal antibody LM13. In roots, the labeling pattern of arad2 was distinct from both that of wild type, arad1 and arad1 arad2. Likewise, in epidermal cell walls of inflorescence stems, LM13 binding differed between arad2 and WILD TYPE, arad1 or arad1 arad2. Altogether, these data show that ARAD2 is associated with arabinan biosynthesis, not redundant with ARAD1, and that the two glycosyltransferases may function in complexes held together by disulfide bridges.