Male Sterile2 (MS2) is predicted to encode a fatty acid reductase required for pollen wall development in Arabidopsis (Arabidopsis thaliana). Transient expression of MS2 in tobacco (Nicotiana benthamiana) leaves resulted in the accumulation of significant levels of C16 and C18 fatty alcohols. Expression of MS2 fused with green fluorescent protein revealed that an amino-terminal transit peptide targets the MS2 to plastids. The plastidial localization of MS2 is biologically important because genetic complementation of MS2 in ms2 homozygous plants was dependent on the presence of its amino-terminal transit peptide or that of the Rubisco small subunit protein amino-terminal transit peptide. In addition, two domains, NAD(P)H-binding domain and sterile domain, conserved in MS2 and its homologs were also shown to be essential for MS2 function in pollen exine development by genetic complementation testing. Direct biochemical analysis revealed that purified recombinant MS2 enzyme is able to convert palmitoyl-Acyl Carrier Protein to the corresponding C16:0 alcohol with NAD(P)H as the preferred electron donor. Using optimized reaction conditions (i.e. at pH 6.0 and 30°C), MS2 exhibits a K(m) for 16:0-Acyl Carrier Protein of 23.3 ± 4.0 μm, a V(max) of 38.3 ± 4.5 nmol mg⁻¹ min⁻¹, and a catalytic efficiency/K(m) of 1,873 M⁻¹ s⁻¹. Based on the high homology of MS2 to other characterized fatty acid reductases, it was surprising that MS2 showed no activity against palmitoyl- or other acyl-coenzyme A; however, this is consistent with its plastidial localization. In summary, genetic and biochemical evidence demonstrate an MS2-mediated conserved plastidial pathway for the production of fatty alcohols that are essential for pollen wall biosynthesis in Arabidopsis.

Key Points• We developed an approach of T-cell-replete haploidentical HSCT with low-dose anti-T-lymphocyte globulin.• Outcomes of suitably matched URD-HSCT and HRD-HSCT are similar, and HRD-HSCT improves outcomes of patients with high-risk leukemia.We developed an approach of T-cell-replete haploidentical hematopoietic stem cell transplantation (HSCT) with low-dose anti-T-lymphocyte globulin and prospectively compared outcomes of all contemporaneous T-cell-replete HSCT performed at our center using matched sibling donors (MSDs), unrelated donors (URDs), and haploidentical related donors (HRDs). From 2008 to 2013, 90 patients underwent MSD-HSCT, 116 underwent URD-HSCT, and 99 underwent HRD-HSCT. HRDs were associated with higher incidences of grades 2 to 4 (42.4%) and severe acute graft-versus-host disease (17.2%) and nonrelapse mortality (30.5%), compared with MSDs (15.6%, 5.6%, and 4.7%, respectively; P < .05), but were similar to URDs, even fully 10/10 HLA-matched URDs. For high-risk patients, a superior graft-versus-leukemia effect was observed in HRD-HSCT, with 5-year relapse rates of 15.4% in HRD-HSCT, 28.2% in URD-HSCT (P 5 .07), and 49.9% in MSD-HSCT (P 5 .002). Furthermore, 5-year disease-free survival rates were not significantly different for patients undergoing transplantation using 3 types of donors, with 63.6%, 58.4%, and 58.3% for MSD, URD, and HRD transplantation, respectively (P 5 .574). Our data indicate that outcomes after HSCT from suitably matched URDs and HRDs with low-dose anti-Tlymphocyte globulin are similar and that HRD improves outcomes of patients with high-risk leukemia. This trial was registered at www.chictr.org (Chinese Clinical Trial Registry) as #ChiCTR

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Suberin, a polyester polymer in the cell wall of terrestrial plants, controls the transport of water and nutrients and protects plant from pathogenic infections and environmental stresses. Structurally, suberin consists of aliphatic and aromatic domains; p-hydroxycinnamates, such as ferulate, p-coumarate, and/or sinapate, are the major phenolic constituents of the latter. By analyzing the ''wallbound'' phenolics of mutant lines of Arabidopsis deficient in a family of acyl-CoA dependent acyltransferase (BAHD) genes, we discovered that the formation of aromatic suberin in Arabidopsis, primarily in seed and root tissues, depends on a member of the BAHD superfamily of enzymes encoded by At5g41040. This enzyme exhibits anhydroxyacid hydroxycinnamoyltransferase activity with an in vitro kinetic preference for feruloyl-CoA and 16-hydroxypalmitic acid. Knocking down or knocking out the At5g41040 gene in Arabidopsis reduces specifically the quantity of ferulate in suberin, but does not affect the accumulation of p-coumarate or sinapate. The loss of the suberin phenolic differentially affects the aliphatic monomer loads and alters the permeability and sensitivity of seeds and roots to salt stress. This highlights the importance of suberin aromatics in the polymer's function.BAHD superfamily ͉ wall-bound phenolics L and plants have evolved different mechanical/defensive machineries to reinforce their cell wall integrity and rigidity to protect themselves from various environmental stresses (1). Along with well recognized lignification, cell wall suberization is another physiologically important strategy to regulate the apoplastic transport of water and solutes and to protect the plant from the invasion of pathogens (1-3).Suberin occurs in the cell walls of external and internal plant tissues. Suberized cells primarily are present in underground tissues (e.g., epidermis, endodermis, exodermis, root and tube phellem), in the coats of mature seeds, in the bundle-sheath cells, and in the phellem of aerial tissues that undergo secondary thickening (2, 4).Structurally, suberin is a complex lipophilic polymer, containing a fatty acid-derived domain (aliphatic suberin) and a (poly)hydroxycinnamate domain (aromatic suberin). The aliphatic suberin is a 3D, glycerol-bridged polyester network, comprised primarily of -hydroxyacids and ␣, -dicarboxylic acids, with chain lengths ranging from C-16 to C-32 (mainly C-18). They exist as discrete components between the plasmalemma and the primary cell wall matrix (2, 3, 5). The aromatic domain is principally composed of p-hydroxycinnamates (e.g., ferulate, p-coumarate, and sinapate) and their derivatives and possibly a low level of monolignols (4, 6). The abundance of those phenolics detected in the suberized tissues varies in different species and ranges as high as approximately 10% of total suberin content (3). The aromatic units of suberin are covalently linked with the aliphatic domain through ester bonds. These aromatic units are then presumably polymerized via radical coupling reactions...

Pectin is a major component of the primary cell wall of higher plants. Some galacturonyl residues in the backbone of pectinaceous polysaccharides are often O-acetylated at the C-2 or C-3 position, and the resulting acetylesters change dynamically during the growth and development of plants. The processes involve both enzymatic acetylation and deacetylation. Through genomic sequence analysis, we identified a pectin acetylesterase (PAE1) from black cottonwood (Populus trichocarpa). Recombinant Pt PAE1 exhibited preferential activity in releasing the acetate moiety from sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectin in vitro. Overexpressing Pt PAE1 in tobacco (Nicotiana tabacum) decreased the level of acetyl esters of pectin but not of xylan. Deacetylation engendered differential changes in the composition and/or structure of cell wall polysaccharides that subsequently impaired the cellular elongation of floral styles and filaments, the germination of pollen grains, and the growth of pollen tubes. Consequently, plants overexpressing PAE1 exhibited severe male sterility. Furthermore, in contrast to the conventional view, PAE1-mediated deacetylation substantially lowered the digestibility of pectin. Our data suggest that pectin acetylesterase functions as an important structural regulator in planta by modulating the precise status of pectin acetylation to affect the remodeling and physiochemical properties of the cell wall's polysaccharides, thereby affecting cell extensibility.

Biologically produced alkanes represent potential renewable alternatives to petroleum-derived chemicals. A cyanobacterial pathway consisting of acyl-Acyl Carrier Protein reductase and an aldehydedeformylating oxygenase (ADO) converts acyl-Acyl Carrier Proteins into corresponding n-1 alkanes via aldehyde intermediates in an oxygen-dependent manner (K m for O 2 , 84 ± 9 μM). In vitro, ADO turned over only three times, but addition of more ADO to exhausted assays resulted in additional product formation. While evaluating the peroxide shunt to drive ADO catalysis, we discovered that ADO is inhibited by hydrogen peroxide (H 2 O 2 ) with an apparent K i of 16 ± 6 μM and that H 2 O 2 inhibition is of mixed-type with respect to O 2 . Supplementing exhausted assays with catalase (CAT) restored ADO activity, demonstrating that inhibition was reversible and dependent on H 2 O 2 , which originated from poor coupling of reductant consumption with alkane formation. Kinetic analysis showed that long-chain (C14-C18) substrates follow Michaelis-Menten kinetics, whereas short and medium chains (C8-C12) exhibit substrate inhibition. A bifunctional protein comprising an N-terminal CAT coupled to a C-terminal ADO (CAT-ADO) prevents H 2 O 2 inhibition by converting it to the cosubstrate O 2 . Indeed, alkane production by the fusion protein is observed upon addition of H 2 O 2 to an anaerobic reaction mix. In assays, CAT-ADO turns over 225 times versus three times for the native ADO, and its expression in Escherichia coli increases catalytic turnovers per active site by fivefold relative to the expression of native ADO. We propose the term "protection via inhibitor metabolism" for fusion proteins designed to metabolize inhibitors into noninhibitory compounds.adlehyde decarbonylase | diiron enzyme | dinuclear iron | enzyme regulation

In this paper, current prediction methods and algorithms for both T- and B cell epitopes are reviewed, and a comprehensive summary of epitope prediction software and databases currently available online is also provided. This review can offer researchers in this field a sense of direction and insights for future work. However, our main purpose is to introduce clinical and basic biomedical researchers who are not familiar with these biological analysis tools and databases to these online resources and to provide guidance on how to use them effectively.