Plant phylogeny drives arboreal caterpillar assemblages across the Holarctic

1. Assemblages of insect herbivores are structured by plant traits such as nutrient content, secondary metabolites, physical traits, and phenology. Many of these traits are phylogenetically conserved, implying a decrease in trait similarity with increasing phylogenetic distance of the host plant taxa. Thus, a metric of phylogenetic distances and relationships can be considered a proxy for phylogenetically conserved plant traits and used to predict variation in herbivorous insect assemblages among co‐occurring plant species.
2. Using a Holarctic dataset of exposed‐feeding and shelter‐building caterpillars, we aimed at showing how phylogenetic relationships among host plants explain compositional changes and characteristics of herbivore assemblages.
3. Our plant–caterpillar network data derived from plot‐based samplings at three different continents included >28,000 individual caterpillar–plant interactions. We tested whether increasing phylogenetic distance of the host plants leads to a decrease in caterpillar assemblage overlap. We further investigated to what degree phylogenetic isolation of a host tree species within the local community explains abundance, density, richness, and mean specialization of its associated caterpillar assemblage.
4. The overlap of caterpillar assemblages decreased with increasing phylogenetic distance among the host tree species. Phylogenetic isolation of a host plant within the local plant community was correlated with lower richness and mean specialization of the associated caterpillar assemblages. Phylogenetic isolation had no effect on caterpillar abundance or density. The effects of plant phylogeny were consistent across exposed‐feeding and shelter‐building caterpillars.
5. Our study reveals that distance metrics obtained from host plant phylogeny are useful predictors to explain compositional turnover among hosts and host‐specific variations in richness and mean specialization of associated insect herbivore assemblages in temperate broadleaf forests. As phylogenetic information of plant communities is becoming increasingly available, further large‐scale studies are needed to investigate to what degree plant phylogeny structures herbivore assemblages in other biomes and ecosystems.

     

Changes in mRNA of Vigna mungo Cotyledons during Seed Germination

Quantitative and qualitative changes of mRNA in Vigna mungocotyledons during seed germination have been investigated. TotalRNA is higher in dry cotyledons and declines during germination.Poly(A)⁺ RNA also is present at a relatively high level in drycotyledons, increases slightly during the first day of germination,and then decreases. Polysomal RNA is very low in dry cotyledonsbut increases rapidly during the first day of germination, andthen declines. The translational activity of the mRNA in a wheatgerm cell-free system is low on day 0 but increases rapidlyon day 1 of germination. Two-dimensional gel electrophoresisof in vitro translation products reveals that many new peptidesare synthesized on day 1 of germination. Synthesis of most ofthese polypeptides continue throughout 5 days of germination. Change in the mRNA population during germination has been investigatedusing cDNA against poly(A)⁺ RNA from 3-day-old cotyledons. Withtotal RNA of day 3 and 5, the cDNA strongly hybridized withRNA similar in size to 25 S ribosomal RNA, but no specific bandsare detected with samples of day 0 or 1. With poly(A)⁺ RNA ofday 5 or 1, the cDNA tends to hybridize with RNAs of relativelysmall molecular size. Cordycepin and -amanitin prevent the increasein poly (A)⁺ RNA content and the appearance of new mRNAs duringthe first day of germination. ¹Present address: Division of Regulation of Macromolecular Function,Institute for Protein Research, Suita City, Osaka 565, Japan. (Received January 13, 1986; Accepted June 10, 1986)     

Augmentation of Interferon Production after Cell-Differentiation of U937 Cells by TPA

Persistent infections with mumps virus were established in several human lymphoid cells of T-cell origin (Molt-4, TALL-1, and CCRF-CEM) and human monocyte cells (U937 and THP-1). 2′,5′-Oligoadenylate synthetase (2–5AS) activity was demonstrated to be only slightly induced by interferon (IFN) or TPA (12-O-tetradecanoyl-phorbol-13-acetate) treatment in these cells. Treatment of the persistently infected cells with IFN or TPA did not stimulate an increase in the amount of synthetase mRNA. Induction of cell differentiation and augmentation of IFN production by TPA were demonstrated in U937 cells persistently infected with mumps virus (U937-MP). Similar results for IFN production were obtained from differentiated U937 cells. It is suggested that cell differentiation of U937 cells might be associated with the development of IFN inducibility.     

Influence of Axis Removal on Amino-, Carboxy- and Endopeptidase Activities in Cotyledons of Germinating Vigna mungo Seeds

Endopeptidase (azocaseolytic enzyme) and carboxypeptidase activitiesin cotyledons of germinating Vigna mungo seeds increased until3 days after the onset of imbibition and decreased thereafter.In detached and incubated cotyledons, the endopeptidase activityincreased only a little while the carboxypeptidase activitycontinued increasing even after 3 days of incubation. The activitiesof leucine-aminopeptidase and alanine-aminopeptidase, exceptfor that of one leucine-aminopeptidase isoenzyme relativelyabundantly present in unimbibed dry cotyledons, increased slightlyon the first day and declined during germination. In detachedcotyledons, the activities maintained their initial levels throughoutthe incubation period. When cotyledons were detached from germinatingseedlings on days 2 and 4 then incubated, the endopeptidaseactivity started to decrease just after removal of the axisbut the carboxypeptidase activity increased more markedly thanwhen the axis remained attached. Exogenously supplied GA₃, kinetin,IAA, or their combinations, showed no significant effect onthe developmental patterns of the endopeptidase and carboxypeptidaseactivities in cotyledons. These results are discussed in relationto the role of the axis in controlling peptidase formation incotyledons of germinating V. mungo seeds. (Received November 18, 1983; Accepted February 28, 1984)     

Nucleotide sequence of the gene coding for four subunits of cytochrome c oxidase from the thermophilic bacterium PS3

The gene coding for four subunits of cytochrome aa3-type oxidase was isolated from a genomic DNA library of the thermophilic bacterium PS3 and sequenced. The N-terminus of each subunit was also sequenced to verify the initiation site of the reading frame. The deduced amino acid sequences contained 615 amino acid residues for subunit I (CO1/caaB product), 333 residues for subunit II (CO2/caaA product), 207 residues for subunit III (CO3/caaC product), and 109 residues for subunit IV (CO4/caaD product) after processing. Re-examination of the sequencing of caa revealed a longer open reading frame for CO1, which contains 14 transmembrane segments instead of 12 [Sone et al. (1988) J. Biochem. 103, 606-610], although the main portions of the sequences constituting cytochrome a (FeA), cytochrome a3 (FeB), and CuB are correct. PS3 CO2 has an additional sequence for cytochrome c after the CuA binding protein portion with 2 transmembrane segments, which is homologous to the mitochondrial counterpart. PS3 CO3 has DCCD-binding glutamyl residues but contains only 5 transmembrane segments, unlike the mitochondrial counterpart, which has 7 segments. The subunits of PS3 cytochrome oxidase (aa3-type) show clear similarity in amino acid sequences with those of cytochrome bo-type oxidase from Escherichia coli as well, in spite of the difference of hemes. PS3 CO3 and CO4 are much more similar to E. coli CO3 and CO4 than to mitochondrial CO3 and CO4, respectively.     

Alicyclic acid metabolism in plants 8. Association, of two enzymes of the shikimate pathway in shoots of Phaseolus mungo seedlings

The association of two enzymes involved in the shikimate pathway,3-dehydroquinate hydro-lyase (EC 4.2.1.10 [EC] ) and shikimate: NADPoxidoreductase (EC 1.1.1.25 [EC] ), was studied with shoots of etiolated4-day-old Phaseolus mungo seedlings. The enzymes were not separableby ammonium sulfate fractionation, sucrose density gradientcentrifugation, polyacrylamide gel electrophoresis and chromatographyon Sephadex G-100 and DEAE-Sephadex A-50. The results are discussedin relation to the channelling function of metabolites in thealicyclic acid metabolism in higher plants. (Received October 28, 1975; )     

Metal ion dependency of serine racemase from Dictyostelium discoideum

D-Serine is known to act as an endogenous co-agonist of the N-methyl-D-aspartate receptor in the mammalian brain and is endogenously synthesized from L-serine by a pyridoxal 5'-phosphate-dependent enzyme, serine racemase. Though the soil-living mycetozoa Dictyostelium discoideum possesses no genes homologous to that of NMDA receptor, it contains genes encoding putative proteins relating to the D-serine metabolism, such as serine racemase, D-amino acid oxidase, and D-serine dehydratase. D. discoideum is an attractive target for the elucidation of the unknown functions of D-serine such as a role in cell development. As part of the elucidation of the role of D-serine in D. discoideum, we cloned, overexpressed, and examined the properties of the putative serine racemase exhibiting 46% amino acid sequence similarity with the human enzyme. The enzyme is unique in its stimulation by monovalent cations such as Na(+) in addition to Mg(2+) and Ca(2+), which are well-known activators for the mammalian serine racemase. Mg(2+) or Na(+) binding caused two- to ninefold enhancement of the rates of both racemization and dehydration. The half-maximal activation concentrations of Mg(2+) and Na(+) were determined to be 1.2?μM and 2.2?mM, respectively. In the L-serine dehydrase reaction, Mg(2+) and Na(+) enhanced the k (cat) value without changing the K (m) value. Alanine mutation of the residues E207 and D213, which correspond to the Mg(2+)-binding site of Schizosaccharomyces pombe serine racemase, abolished the Mg(2+)- and Na(+)-dependent stimulation. These results suggest that Mg(2+) and Na(+) share the common metal ion-binding site.     

Expression of Six Proteins Causes Reprogramming of Porcine Fibroblasts Into Induced Pluripotent Stem Cells With Both Active X Chromosomes

In this study, we created porcine‐induced pluripotent stem (iPS) cells with the expression of six reprogramming factors (Oct3/4, Klf4, Sox2, c‐Myc, Lin28, and Nanog). The resulting cells showed growth dependent on LIF (leukemia inhibitory factor) and expression of multiple stem cell markers. Furthermore, the iPS cells caused teratoma formation with three layers of differentiation and had both active X chromosomes (XaXa). Our iPS cells satisfied the both of important characteristics of stem cells: teratoma formation and activation of both X chromosomes. Injection of these iPS cells into morula stage embryos showed that these cells participate in the early stage of porcine embryogenesis. Furthermore, the RNA‐Seq analysis detected that expression levels of endogenous pluripotent related genes, NANOG, SOX2, ZFP42, OCT3/4, ESRRB, and ERAS were much higher in iPS with six factors than that with four reprogramming factors. We can conclude that the expression of six reprogramming factors enables the creation of porcine iPS cells, which is partially close to naive iPS state. J. Cell. Biochem. 118: 537–553, 2017. © 2016 Wiley Periodicals, Inc.     

Cleavage of syndecan-1 by membrane type matrix metalloproteinase-1 stimulates cell migration

The transmembrane heparan sulfate proteoglycan syndecan-1 was identified from a human placenta cDNA library by the expression cloning method as a gene product that interacts with membrane type matrix metalloproteinase-1 (MT1-MMP). Co-expression of MT1-MMP with syndecan-1 in HEK293T cells promoted syndecan-1 shedding, and concentration of cell-associated syndecan-1 was reduced. Treatment of cells with MMP inhibitor BB-94 or tissue inhibitor of MMP (TIMP)-2 but not TIMP-1 interfered with the syndecan-1 shedding promoted by MT1-MMP expression. In contrast, syndecan-1 shedding induced by 12-O-tetradecanoylphorbol-13-acetate treatment was inhibited by BB-94 but not by either TIMP-1 or TIMP-2. Shedding of syndecan-1 was also induced by MT3-MMP but not by other MT-MMPs. Recombinant syndecan-1 core protein was shown to be cleaved by recombinant MT1-MMP or MT3-MMP preferentially at the Gly245-Leu246 peptide bond. HT1080 fibrosarcoma cells stably transfected with the syndecan-1 cDNA (HT1080/SDC), which express endogenous MT1-MMP, spontaneously shed syndecan-1. Migration of HT1080/SDC cells on collagen-coated dishes was significantly slower than that of control HT1080 cells. Treatment of HT1080/SDC cells with BB-94 or TIMP-2 induced accumulation of syndecan-1 on the cell surface, concomitant with further retardation of cell migration. Substitution of Gly245 of syndecan-1 with Leu significantly reduced shedding from HT1080/SDC cells and cell migration. These results suggest that the shedding of syndecan-1 promoted by MT1-MMP through the preferential cleavage of Gly245-Leu246 peptide bond stimulates cell migration.