Small rubber particle proteins from Taraxacum brevicorniculatum promote stress tolerance and influence the size and distribution of lipid droplets and artificial poly(cis‐1,4‐isoprene) bodies

Natural rubber biosynthesis occurs on rubber particles, i.e. organelles resembling small lipid droplets localized in the laticifers of latex‐containing plant species, such as Hevea brasiliensis and Taraxacum brevicorniculatum. The latter expresses five small rubber particle protein (SRPP) isoforms named TbSRPP1–5, the most abundant proteins in rubber particles. These proteins maintain particle stability and are therefore necessary for rubber biosynthesis. TbSRPP1–5 were transiently expressed in Nicotiana benthamiana protoplasts and the proteins were found to be localized on lipid droplets and in the endoplasmic reticulum, with TbSRPP1 and TbSRPP3 also present in the cytosol. Bimolecular fluorescence complementation confirmed pairwise interactions between all proteins except TbSRPP2. The corresponding genes showed diverse expression profiles in young T. brevicorniculatum plants exposed to abiotic stress, and all except TbSRPP4 and TbSRPP5 were upregulated. Young Arabidopsis thaliana plants that overexpressed TbSRPP2 and TbSRPP3 tolerated drought stress better than wild‐type plants. Furthermore, we used rubber particle extracts and standards to investigate the affinity of the TbSRPPs for different phospholipids, revealing a preference for negatively charged head groups and 18:2/16:0 fatty acid chains. This finding may explain the effect of TbSRPP3–5 on the dispersity of artificial poly(cis‐1,4‐isoprene) bodies and on the lipid droplet distribution we observed in N. benthamiana leaves. Our data provide insight into the assembly of TbSRPPs on rubber particles, their role in rubber particle structure, and the link between rubber biosynthesis and lipid droplet‐associated stress responses, suggesting that SRPPs form the basis of evolutionarily conserved intracellular complexes in plants.     

Toxic gain of function from mutant FUS protein is crucial to trigger cell autonomous motor neuron loss

FUS is an RNA‐binding protein involved in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Cytoplasmic FUS‐containing aggregates are often associated with concomitant loss of nuclear FUS. Whether loss of nuclear FUS function, gain of a cytoplasmic function, or a combination of both lead to neurodegeneration remains elusive. To address this question, we generated knockin mice expressing mislocalized cytoplasmic FUS and complete FUS knockout mice. Both mouse models display similar perinatal lethality with respiratory insufficiency, reduced body weight and length, and largely similar alterations in gene expression and mRNA splicing patterns, indicating that mislocalized FUS results in loss of its normal function. However, FUS knockin mice, but not FUS knockout mice, display reduced motor neuron numbers at birth, associated with enhanced motor neuron apoptosis, which can be rescued by cell‐specific CRE‐mediated expression of wild‐type FUS within motor neurons. Together, our findings indicate that cytoplasmic FUS mislocalization not only leads to nuclear loss of function, but also triggers motor neuron death through a toxic gain of function within motor neurons.     

Nest-site selection and its impact on breeding success of the Lesser Kestrel,Falco naumanni,in the North of Iran (Aves: Falconiformes)

The Lesser Kestrel (Falco naumanni) is a small migratory falcon which nests coloni- ally on inland cliffs and ruined buildings. Bandar Turkman city holds one of the most important breeding colonies in Iran. It nests in holes in roofs, walls or on ledges of buildings throughout of the city. We tried to find out whether there is a relationship between nest-site selection and breeding success. Although height from the ground is the most important factor in nest-site selection by F. naumanni, height from the floor and distance to the nearest neighbour are other main factors which affect breeding success. This could be the result of accessibility by human and natural predators such as domestic cats which threaten nests. The number of possible nest-sites in the study area is limited as many old, ruined buildings are being replaced by new construc- tions; this colonially breeding bird species therefore suffers from a lack of highly suitable nest-sites and this directly affect breeding success.     

MEGAN Community Edition - Interactive Exploration and Analysis of Large-Scale Microbiome Sequencing Data

There is increasing interest in employing shotgun sequencing, rather than amplicon sequencing, to analyze microbiome samples. Typical projects may involve hundreds of samples and billions of sequencing reads. The comparison of such samples against a protein reference database generates billions of alignments and the analysis of such data is computationally challenging. To address this, we have substantially rewritten and extended our widely-used microbiome analysis tool MEGAN so as to facilitate the interactive analysis of the taxonomic and functional content of very large microbiome datasets. Other new features include a functional classifier called InterPro2GO, gene-centric read assembly, principal coordinate analysis of taxonomy and function, and support for metadata. The new program is called MEGAN Community Edition (CE) and is open source. By integrating MEGAN CE with our high-throughput DNA-to-protein alignment tool DIAMOND and by providing a new program MeganServer that allows access to metagenome analysis files hosted on a server, we provide a straightforward, yet powerful and complete pipeline for the analysis of metagenome shotgun sequences. We illustrate how to perform a full-scale computational analysis of a metagenomic sequencing project, involving 12 samples and 800 million reads, in less than three days on a single server. All source code is available here: https://github.com/danielhuson/megan-ce     

Mitochondria mediate septin cage assembly to promote autophagy of Shigella

Septins, cytoskeletal proteins with well‐characterised roles in cytokinesis, form cage‐like structures around cytosolic Shigella flexneri and promote their targeting to autophagosomes. However, the processes underlying septin cage assembly, and whether they influence S. flexneri proliferation, remain to be established. Using single‐cell analysis, we show that the septin cages inhibit S. flexneri proliferation. To study mechanisms of septin cage assembly, we used proteomics and found mitochondrial proteins associate with septins in S. flexneri‐infected cells. Strikingly, mitochondria associated with S. flexneri promote septin assembly into cages that entrap bacteria for autophagy. We demonstrate that the cytosolic GTPase dynamin‐related protein 1 (Drp1) interacts with septins to enhance mitochondrial fission. To avoid autophagy, actin‐polymerising Shigella fragment mitochondria to escape from septin caging. Our results demonstrate a role for mitochondria in anti‐Shigella autophagy and uncover a fundamental link between septin assembly and mitochondria.     

Isoenzymmuster der Phosphoglucomutase der menschlichen Spermien (Sp.-PGM1)

Summary The isoenzyme patterns of phosphoglucomutase (PGM₁) were investigated in human spermatozoa (Sp.-PGM₁). The three phenotypes of PGM₁-polymorphism commonly found in erythrocytes could also be demonstrated in spermatozoa. It was also found that these patterns differ in spermatozoa quantitatively and in the case of phenotype PGM₁ 1-1 a qualitative difference could also be observed. The eventual significance of these findings in forensic medicine were briefly mentioned.     

Synthesis of 2-acetamido-2-deoxy-4-O-alpha-L-fucopyranosyl-alpha-D-glucopyranose]

Condensation of 2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl bromide with benzyl 2-acetamido-3,6-di-O-benzyl-alpha-D-glucopyranoside in dichloromethane-N,N-dimethylformamide, in the presence of tetraethylammonium bromide, diisopropylethylamine, and molecular sieve (halide ion-catalyzed reaction), gave benzyl 2-acetamido-3,6-di-O-benzyl-2 deoxy-4-O-(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-alpha-D-glucopyranoside in crystalline form in 82% yield. Hydrogenolysis of the benzyl groups gave the title disaccharide, in crystalline form in 90% yield, which was characterized by a crystalline peracetylated alpha-D derivative.     

Structural characterization of sulfated glycosaminoglycans by fast atom bombardment mass spectrometry: application to heparin fragments prepared by chemical synthesis

We report herein the results of f.a.b.-m.s. experiments conducted on synthetic fragments of glycosaminoglycans, one of them representing the pentasaccharidic sequence present in heparin and responsible for the binding to antithrombin III, and the others being related to this sequence. The results indicate that f.a.b.-m.s. can be very useful for the structural analysis of sulfated glycosaminoglycans. The relatively small amounts of sample required enable molecular characterization at physiologically significant levels. In contrast to the chondroitin sulfates, the heparin saccharides analyzed and reported here do not provide sequence information. The data indicate that glycosidic rupture is not a process competing with the much more facile loss of N-sulfite residues. Dominating the spectra are a series of molecular-weight-related ions (distributed to indicate the associated countercation composition), and fragments related directly to sulfite elimination. This f.a.b.-induced, facile loss of sulfite may impose limitations in molecular-weight analysis for the larger oligomers.     

Chemical synthesis of the human blood-group P1-antigenic determinant

Condensation of known benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-alpha-D-glucopyranoside with 2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl chloride in dichloromethane in the presence of 2,4,6-trimethylpyridine, silver triflate, and molecular sieve 4A gave benzyl O-(2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl)-(1 leads to 4)-O-(2,3,6-tri-O-benzyl-beta-D-galactopyranosyl)-(1 leads to 4)-2-acetamido-3,6-di-O-benzyl-2-deoxy-alpha-D-glucopyranoside. Catalytic hydrogenolysis gave crystalline O-alpha-D-galactopyranosyl-(1 leads to 4)-O-beta-D-galactopyranosyl-(1 leads to 4)-2-acetamido-2-deoxy-alpha -D-glucopyranose, the human blood-group P1-antigenic determinant. A similar sequence of reactions was performed starting from allyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside, in order to prepare a derivative of this determinant suitable for linkage to carrier molecules.     

Potent and broad-spectrum antibacterial activity of indole-based bisamidine antibiotics: Synthesis and SAR of novel analogs of MBX 1066 and MBX 1090

The prevalence of drug-resistant bacteria in the clinic has propelled a concerted effort to find new classes of antibiotics that will circumvent current modes of resistance. We have previously described a set of bisamidine antibiotics that contains a core composed of two indoles and a central linker. The first compounds of the series, MBX 1066 and MBX 1090, have potent antibacterial properties against a wide range of Gram-positive and Gram-negative bacteria. We have conducted a systematic exploration of the amidine functionalities, the central linker, and substituents at the indole 3-position to determine the factors involved in potent antibacterial activity. Some of the newly synthesized compounds have even more potent and broad-spectrum activity than MBX 1066 and MBX 1090.