Larvae of Leptus (Acarina:Erythraeidae), free-living or ectoparasitic on arachnids and lower insects of Australia and Papua New Guinea, with descriptions of reared post-larval instars

Leptus larvae (Acarina:Erythraeidae) of Australia and New Guinea, collected either free-living or ectoparasitic on Arachnida or lower Insecta, are comprehensively reviewed. For Australia the following new species are described. From Scorpionida: L. barmeedius, L. baudini, L. carduus, L. hitchcocki, L. korematus, L. pistoris, L. stnithi and L. urodaci; from Araneae: L. minno; from Insecta: L. norrisi (Archaeognatha); L.flindersi (Blattodea); L. cheesmanae (Phasmatodea); L. bankensis, L. calcar, L. cultellus, L. foliatus, L. lighti, L. pincheni and L. tindalei (Orthoptera, Acridoidea); L. batjallus, L. clavatus, L. clelandi. L. elderi, L.fisheri (Hemiptera); L. grossi and L. puniceus (free-living only); some of the preceding species were also captured free-living. From Papua New Guinea the following new species are described: L. calcar (Acridoidea); L. cheesmanae (Orthoptera:'cricket') (both of these species also from Australia); L. lorarius, L. scutellatus and L. triacanthus (free-living). Additional host and other records are given for previously described species, originally described as ectoparasites of Insecta:from Australia: L. bathypogonus Womersley (Acridoidea); L. cerambycius Southcott (free-living); L. charon Southcott (Araneae, Scorpionida); L.faini Southcott (Araneae); L. orthrius Southcott (Hemiptera); from Papua New Guinea: L. draco Southcott (Odonata, Acridoidea, Tettiginioidea, Phasmatodea, Hemiptera). Protonymphs are described of L. barmeedius, L. baudini, L. calcar, L. charon, L.flindersi, L. orthrius and L. smithi. Deutonymphs are described of L. calcar, L. charon, L. flindersi and L. smithi. A key is provided for the known larvae, protonymphs and deutonymphs of Leptus of Australia and Papua New Guinea. Teratological abnormalities are recorded for L. cultellus, L. fisheri, L, minno and L. urodaci.     

丽盲蝽属(丽盲蝽亚属)中国种类修订(半翅目:盲蝽科:盲蝽亚科)(英文)

对丽盲蝽属 (丽盲蝽亚属 )Lygocoris (subg .Lygocoris)的中国种类作了修订。文中共包括 19个种 ,其中有 12新种 ,1个中国新纪录种 ,并包括 1项新等级的认定。即暗胝丽盲蝽L .(L .)calligersp .nov .(正模 :四川峨眉山九老洞 ) ,程氏丽盲蝽L .(L .)chengisp .nov .(正模 :四川峨眉山大乘寺 ) ,晕斑丽盲蝽L .(L .)diffusomaculatussp .nov .(正模 :甘肃榆中兴隆山 ) ,淡色丽盲蝽L .(L .)dilutussp .nov .(正模 :甘肃夏河县合作 ) ,锈褐丽盲蝽L .(L .) ferrugineussp .nov .(正模 :云南哀牢山 ) ,褐盾丽盲蝽L .(L .) fuscoscutel latus (Reuter ,190 6 )stat .nov .[由L .(L .)striicornisvar.fuscoscutellatus升为种级阶元 ],广西丽盲蝽L .(L .) guangxiensissp .nov .(正模 :广西龙胜 ) ,东亚丽盲蝽L .(L .)idoneus(Linnavuori,196 3) (中国新纪录种 ) ,完脊丽盲蝽L .(L .)integricarinatussp .nov .(甘肃榆中麻家寺 ) ,林氏丽盲蝽L .(L .)linnavuoriisp .nov .(云南哀牢山簸箕坝 ) ,长翅丽盲蝽L .(L .)longipennis (Reuter ,190 6 ) ,斑盾丽盲蝽L .(L .)maculis cutellatussp .nov .(四川理县刷经寺 ) ,原丽盲蝽L .(L .) pabulinus (Linnaeus ,176 1) ,红盾丽盲蝽L .(L .)rufiscutellatussp .nov .(甘     

The putative terminase subunit of herpes simplex virus 1 encoded by UL28 is necessary and sufficient to mediate interaction between pUL15 and pUL33

Viral terminases play essential roles as components of molecular motors that package viral DNA into capsids. Previous results indicated that the putative terminase subunits of herpes simplex virus 1 (HSV-1) encoded by U(L)15 and U(L)28 (designated pU(L)15 and pU(L)28, respectively) coimmunoprecipitate with the U(L)33 protein from lysates of infected cells. All three proteins are among six required for HSV-1 DNA packaging but dispensable for assembly of immature capsids. The current results show that in both infected- and uninfected-cell lysates, pU(L)28 coimmunoprecipitates with either pU(L)33 or pU(L)15, whereas pU(L)15 and pU(L)33 do not coimmunoprecipitate unless pU(L)28 is present. The U(L)28 protein was sufficient to stabilize pU(L)33 from proteasomal degradation in an engineered cell line and was necessary to stabilize pU(L)33 in infected cells, whereas pU(L)15 had no such effects. The presence of pU(L)33 was dispensable for the pU(L)15/pU(L)28 interaction in lysates of both infected and uninfected cells but augmented the tendency for pU(L)15 and pU(L)28 to coimmunoprecipitate. These data suggest that pU(L)28 and pU(L)33 interact directly and that pU(L)15 interacts directly with pU(L)28 but only indirectly with pU(L)33. It is logical to propose that the indirect interaction of pU(L)15 and pU(L)33 is mediated through the interaction of both proteins with pU(L)28. The data also suggest that one function of pU(L)33 is to optimize the pU(L)15/pU(L)28 interaction.     

The anesthetic efficacy of eugenol and the essential oils of Lippia alba and Aloysia triphylla in post-larvae and sub-adults of Litopenaeus vannamei (Crustacea, Penaeidae)

The aim of this study was to evaluate the anesthesia induction and recovery times of sub-adult and post-larvae white shrimp (Litopenaeus vannamei) that were treated with eugenol and the essential oils (EOs) from Lippia alba and Aloysia triphylla. Oxidative stress parameters in the hemolymph of this species were also analyzed. The concentrations of eugenol, A. triphylla EO and L. alba EO recommended for anesthesia were 200, 300 and 750 μL L(-1) for sub-adults and 175, 300 and 500 μL L(-1) for post-larvae, respectively. The concentrations studied during the transport of sub-adults were between 20 and 50 μL L(-1) eugenol, 20-30 μL L(-1)A. triphylla EO and 50 μL L(-1)L. alba EO. For post-larvae, the optimal concentrations for transport were 20 μL L(-1) eugenol and between 20 and 50 μL L(-1)A. triphylla EO. The white shrimp sub-adults that were exposed to A. triphylla EO (20 μL L(-1)) showed increases in their total antioxidant capacities (150%), catalase (70%) and glutathione-S-transferase (615%) activity after 6 h. L. alba EO (50 μL L(-1)) and eugenol (20 μL L(-1)) also increased GST activity (1292 and 1315%) after 6 h, and eugenol (20 μL L(-1)) decreased the total antioxidant capacity (100%). Moreover, concentrations above 30 μL L(-1) for the EOs of A. triphylla and L. alba and 20 μL L(-1) eugenol were effective at inducing anesthesia and improving the antioxidant system against reactive oxygen species (ROS) after 6 h.     

Characterization and analysis of posttranslational modifications of the human large cytoplasmic ribosomal subunit proteins by mass spectrometry and Edman sequencing

The 60S ribosomal proteins were isolated from ribosomes of human placenta and separated by reversed phase HPLC. The fractions obtained were subjected to trypsin and Glu-C digestion and analyzed by mass fingerprinting (MALDI-TOF), MS/MS (ESI), and Edman sequencing. Forty-six large subunit proteins were found, 22 of which showed masses in accordance with the SwissProt database (June 2002) masses (proteins L6, L7, L9, L13, L15, L17, L18, L21, L22, L24, L26, L27, L30, L32, L34, L35, L36, L37, L37A, L38, L39, L41). Eleven (proteins L7, L10A, L11, L12, L13A, L23, L23A, L27A, L28, L29, and P0) resulted in mass changes that are consistent with N-terminal loss of methionine, acetylation, internal methylation, or hydroxylation. A loss of methionine without acetylation was found for protein L8 and L17. For nine proteins (L3, L4, L5, L7A, L10, L14, L19, L31, and L40), the molecular masses could not be determined. Proteins P1 and protein L3-like were not identified by the methods applied.     

Vaccinia Virus Envelope D8L Protein Binds to Cell Surface Chondroitin Sulfate and Mediates the Adsorption of Intracellular Mature Virions to Cells

We previously showed that an envelope A27L protein of intracellular mature virions (IMV) of vaccinia virus binds to cell surface heparan sulfate during virus infection. In the present study we identified another viral envelope protein, D8L, that binds to chondroitin sulfate on cells. Soluble D8L protein interferes with the adsorption of wild-type vaccinia virions to cells, indicating a role in virus entry. To explore the interaction of cell surface glycosaminoglycans and vaccinia virus, we generated mutant viruses from a control virus, WR32-7/Ind14K (A27L(+) D8L(+)) to be defective in expression of either the A27L or the D8L gene (A27L(+) D8L(-) or A27L(-) D8L(+)) or both (A27L(-) D8L(-)). The A27L(+) D8L(+) and A27L(-) D8L(+) mutants grew well in BSC40 cells, consistent with previous observations. However, the IMV titers of A27L(+) D8L(-) and A27L(-) D8L(-) viruses in BSC40 cells were reduced, reaching only 10% of the level for the control virus. The data suggested an important role for D8L protein in WR32-7/Ind14K virus growth in cell cultures. A27L protein, on the other hand, could not complement the functions of D8L protein. The low titers of the A27L(+) D8L(-) and A27L(-) D8L(-) mutant viruses were not due to defects in the morphogenesis of IMV, and the mutant virions demonstrated a brick shape similar to that of the control virions. Furthermore, the infectivities of the A27L(+) D8L(-) and A27L(-) D8L(-) mutant virions were 6 to 10% of that of the A27L(+) D8L(+) control virus. Virion binding assays revealed that A27L(+) D8L(-) and A27L(-) D8L(-) mutant virions bound less well to BSC40 cells, indicating that binding of viral D8L protein to cell surface chondroitin sulfate could be important for vaccinia virus entry.     

The role of endocytosis in regulating L1-mediated adhesion

L1 is a neural cell adhesion molecule critical for neural development. Full-length L1 (L1(FL)) contains an alternatively spliced cytoplasmic sequence, RSLE, which is absent in L1 expressed in nonneuronal cells. The RSLE sequence follows a tyrosine, creating an endocytic motif that allows rapid internalization via clathrin-mediated endocytosis. We hypothesized that L1(FL) would internalize more rapidly than L1 lacking the RSLE sequence (L1(Delta)(RSLE)) and that internalization might regulate L1-mediated adhesion. L1 internalization was measured by immunofluorescence microscopy and by uptake of (125)I-anti-rat-L1 antibody, demonstrating that L1(FL) is internalized 2-3 times faster than L1(Delta)(RSLE). Inhibition of clathrin-mediated endocytosis slowed internalization of L1(FL) but did not affect initial uptake of L1(Delta)(RSLE). To test whether L1 endocytosis regulates L1 adhesion, cell aggregation rates were tested. L1(Delta)(RSLE) cells aggregated two times faster than L1(FL) cells. Inhibition of clathrin-mediated endocytosis increases the aggregation rate of the L1(FL) cells to that of L1(Delta)(RSLE) cells. Our results demonstrate that rapid internalization of L1 dramatically affects L1 adhesion.     

Genetic basis for the hierarchical interaction between Tobamovirus spp. and L resistance gene alleles from different pepper species

The pepper L gene conditions the plant's resistance to Tobamovirus spp. Alleles L(1), L(2), L(3), and L(4) confer a broadening spectra of resistance to different virus pathotypes. In this study, we report the genetic basis for the hierarchical interaction between L genes and Tobamovirus pathotypes. We cloned L(3) using map-based methods, and L(1), L(1a), L(1c), L(2), L(2b), and L(4) using a homology-based method. L gene alleles encode coiled-coil, nucleotide-binding, leucine-rich repeat (LRR)-type resistance proteins with the ability to induce resistance response to the viral coat protein (CP) avirulence effectors by themselves. Their different recognition spectra in original pepper species were reproduced in an Agrobacterium tumefaciens-mediated transient expression system in Nicotiana benthamiana. Chimera analysis with L(1), which showed the narrowest recognition spectrum, indicates that the broader recognition spectra conferred by L(2), L(2b), L(3), and L(4) require different subregions of the LRR domain. We identified a critical amino acid residue for the determination of recognition spectra but other regions also influenced the L genes' resistance spectra. The results suggest that the hierarchical interactions between L genes and Tobamovirus spp. are determined by the interaction of multiple subregions of the LRR domain of L proteins with different viral CP themselves or some protein complexes including them.     

U(L)31 and U(L)34 proteins of herpes simplex virus type 1 form a complex that accumulates at the nuclear rim and is required for envelopment of nucleocapsids

The herpes simplex virus type 1 (HSV-1) U(L)34 protein is likely a type II membrane protein that localizes within the nuclear membrane and is required for efficient envelopment of progeny virions at the nuclear envelope, whereas the U(L)31 gene product of HSV-1 is a nuclear matrix-associated phosphoprotein previously shown to interact with U(L)34 protein in HSV-1-infected cell lysates. For these studies, polyclonal antisera directed against purified fusion proteins containing U(L)31 protein fused to glutathione-S-transferase (U(L)31-GST) and U(L)34 protein fused to GST (U(L)34-GST) were demonstrated to specifically recognize the U(L)31 and U(L)34 proteins of approximately 34,000 and 30,000 Da, respectively. The U(L)31 and U(L)34 gene products colocalized in a smooth pattern throughout the nuclear rim of infected cells by 10 h postinfection. U(L)34 protein also accumulated in pleiomorphic cytoplasmic structures at early times and associated with an altered nuclear envelope late in infection. Localization of U(L)31 protein at the nuclear rim required the presence of U(L)34 protein, inasmuch as cells infected with a U(L)34 null mutant virus contained U(L)31 protein primarily in central intranuclear domains separate from the nuclear rim, and to a lesser extent in the cytoplasm. Conversely, localization of U(L)34 protein exclusively at the nuclear rim required the presence of the U(L)31 gene product, inasmuch as U(L)34 protein was detectable at the nuclear rim, in replication compartments, and in the cytoplasm of cells infected with a U(L)31 null virus. When transiently expressed in the absence of other viral factors, U(L)31 protein localized diffusely in the nucleoplasm, whereas U(L)34 protein localized primarily in the cytoplasm and at the nuclear rim. In contrast, coexpression of the U(L)31 and U(L)34 proteins was sufficient to target both proteins exclusively to the nuclear rim. The proteins were also shown to directly interact in vitro in the absence of other viral proteins. In cells infected with a virus lacking the U(S)3-encoded protein kinase, previously shown to phosphorylate the U(L)34 gene product, U(L)31 and U(L)34 proteins colocalized in small punctate areas that accumulated on the nuclear rim. Thus, U(S)3 kinase is required for even distribution of U(L)31 and U(L)34 proteins throughout the nuclear rim. Taken together with the similar phenotypes of the U(L)31 and U(L)34 deletion mutants, these data strongly suggest that the U(L)31 and U(L)34 proteins form a complex that accumulates at the nuclear membrane and plays an important role in nucleocapsid envelopment at the inner nuclear membrane.     

Copper(II) complexes of some N-substituted bis(aminomethyl)phosphinate ligands. An integrated EPR study of microspeciation and coordination modes by the two-dimensional simulation method

Copper(II) complexes of bis(aminomethyl)phosphinic acid (L1), bis(N-glycino-N-methyl)phosphinic acid (L2), bis(N-benzylglycino-N-methyl)phosphinic acid (L3), bis(l-prolino-N-methyl)phosphinic acid (L4) and bis(iminodicarboxymethyl-N-methyl)phosphinic acid (L5) were studied in aqueous solution by pH-potentiometric and electron paramagnetic resonance (EPR) spectroscopic methods. The EPR spectrum packages recorded at various ligand-to-metal concentration ratios and pH's were analyzed (after matrix rank analysis by the method of residual intensities as a complementary method) by the two-dimensional computer simulation method, which simultaneously determines the formation constants and the EPR parameters of the various (micro)species. L1 forms mono and bis complexes in different protonation states; for the other ligands, the mono complexes are always prevalent. For steric reasons, the formation of CuL is shifted to increasingly higher pH regions in the sequence L2, L3 and L4. CuLH was identified for L3, L4 and L5, and also CuLH(2) for L4 and L5. Cu(2)L(2) was found in small amounts for L3 and L4, while it predominates at pH>4 for L5. For L5, Cu(2)L(2)H(2) was also detected. For the ligands that form dimeric metal complexes in equimolar solution or at a ligand excess, Cu(2)L is formed at a metal ion excess. Ligation of the phosphinate O was suggested by indirect proofs in the protonated complexes of L1. For the ligands L2, L3 and L4, the copper(II) coordination in various species in different protonation states is reminiscent of that in the mono and bis complexes of simple amino acids. For the bis(aminomethyl)phosphinates, however, the cis positions of the amino groups in CuL are ensured by the structure of the ligand, and the isomers differ from each other in the (equatorial or axial) position of the second carboxylate group.     

DNA cleavage and packaging proteins encoded by genes U(L)28, U(L)15, and U(L)33 of herpes simplex virus type 1 form a complex in infected cells

Previous studies have indicated that the U(L)6, U(L)15, U(L)17, U(L)28, U(L)32, and U(L)33 genes are required for the cleavage and packaging of herpes simplex viral DNA. To identify proteins that interact with the U(L)28-encoded DNA binding protein of herpes simplex virus type 1 (HSV-1), a previously undescribed rabbit polyclonal antibody directed against the U(L)28 protein fused to glutathione S-transferase was used to immunopurify U(L)28 and the proteins with which it associated. It was found that the antibody specifically coimmunoprecipitated proteins encoded by the genes U(L)28, U(L)15, and U(L)33 from lysates of both HEp-2 cells infected with HSV-1(F) and insect cells infected with recombinant baculoviruses expressing these three proteins. In reciprocal reactions, antibodies directed against the U(L)15- or U(L)33-encoded proteins also coimmunoprecipitated the U(L)28 protein. The coimmunoprecipitation of the three proteins from HSV-infected cells confirms earlier reports of an association between the U(L)28 and U(L)15 proteins and represents the first evidence of the involvement of the U(L)33 protein in this complex.     

Toward the phylogeny of Caucasian rock lizards: implications from mitochondrial DNA gene sequences (Reptilia: Lacertidae)

A maximum parsimony phylogeny of 14 Caucasian species of rock lizards, genus Ijicerta , subgenus Archaeolacerta , was constructed from mitochondrial cytochrome b and ATPase 6 partial gene sequences. Congruence analyses were carried out between the two genes. A synthesis of the data sets reveals three well supported monophyletic groups: (1) the caucasica group including ( Lacerta derjugini (( Lalpina, L. clarkorum ) ( L. caucasica, L. daghestanica ))); (2) the rudis group including ( L. parvula ( L. portschinskii ( L. vakntini, L. rudis ))); and (3) the saxicola group including ( L. mixta ( L. nairensis ( L. saxicola, L. raddeijj ). Despite the diagnosis of three groups, the placement of L. praticola as a basal taxon is uncertain, as are the relationships among the three groups. The mitochondrial DNA sequence data suggested prior hybridization between L. mixta and L. alpina and possibly between L. saxicola and L. nairensis. Lacerta raddei was resolved as a paraphyletic species on the mtDNA tree; this may result from either hybridization or random gene sorting.     

A taxonomic revision of Labiostrongylus (Labiostrongylus) (Yorke & Maplestone, 1926) and Labiostrongylus (Labiomultiplex) n. subg. (Nematoda: Cloacinidae) from macropodid and potoroid marsupials

The morphological characters used to differentiate species in the genus Labiostrongylus Yorke & Maplestone, 1926, parasitic in macropodid and potoroid marsupials, are discussed. The genus is divided into three subgenera Labiostrongylus (Labiostrongylus), L. (Labiomultiplex) n. subg. and L. (Labiosimplex) n. subg. on the basis of the presence or absence of interlabia and the morphology of the oesophagus. A key to the subgenera is given and a detailed revision of two of the subgenera is presented. Keys to each of the subgenera are given, the species discussed being: L. (L.) labiostrongylus) (type-species) (syn. L. (L.) insularis, L. (L.) grandis, L. (L.) macropodis sp. inq. and L. (L.) nabarlekensis n. sp., in the subgenus Labiostrongylus, and L. (Lm.) eugenii, L. (Lm.) novaeguineae, L. (Lm.) onychogale, L. (Lm.) uncinatus, L. (Lm.) billardierii n. sp., L. (Lm.) constrictis n. sp., L. (Lm.) kimberleyensis n. sp., L. (Lm.) thylogale n. sp., and L. (Lm.) potoroi, n. sp., in the subgenus Labiomultiplex.     

Stereo-structural prediction and IR-characteristic band assignment of amorphous protonated forms of homodipeptides (L)-Phe-(L)-Phe, (L)-Trp-(L)-Trp, (L)-Tyr-(L)-Tyr and the neutral - (L)-Trp-(L)-Trp. Ab initio approximation and solid-state linear-polarized IR-spectroscopy

Stereo-structures of protonated (L)-phenylalanine ((L)-Phe), (L)-tyrosine ((L)-Tyr) and (L)-tryptophan ((L)-Trp) containing homodipeptides ((L)-Tyr-(L)-Tyr, (L)-Phe-(L)-Phe, (L)-Trp-(L)-Trp) are carried out by ab initio calculations. The obtained data in gas phase are compared with experimental ones, received by linear-dichroic infrared (IR-LD) spectroscopy of solids, oriented as suspension in nematic mesophase. An observation of a good correlation between theoretical and spectroscopic geometry parameters established and illustrated the possibilities of this complex study approach for the prediction of the stereo-structures in compounds in solid state. The protonation leads to little variance in the bond lengths and angles, expecting the COO(-) fragment, where a distortion of equalized COO(-) bond lengths, stabilizing a C=O double bond and C-O(H) one is established. Significant deviations of the dihedral angles as a result of the protonation are obtained in the skeletal aliphatic and amide- fragments. In (L)-Tyr-(L)-Tyr and (L)-Phe-(L)-Phe, a deviation of O=C-N-H torsion angle about 10-14(0) is predicted. The calculations show a trans-amide configuration in (L)-Trp-(L)-Trp and a cis-one after its protonation.     

Isolation of eukaryotic ribosomal proteins. Purification and characterization of the 60 S ribosomal subunit proteins L4, L5, L7, L9, L11, L12, L13, L21, L22, L23, L26, L27, L30, L33, L35', L37, and L39.

The proteins of the large subunit of rat liver ribosomes were separated into seven groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5. Seventeen proteins (L4, L5, L7, L9, L11, L12, L13, L21, L22, L23, L26, L27, L30, L33, L35', L37, and L39) were isolated from three of the groups (B60, D60, G60) by ion exchange chromatography on carboxymethylcellulose and by filtration through Sephadex. The amount of protein obtained varied from 0.5 to 15 mg. Eight of the proteins (L9, L11, L13, L21, L22, L35', L37 and L39) had no detectable contamination; the impurities in the others were no greater than 9%. The molecular weight of the proteins was estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate; the amino acid composition was determined.     

Karyology of Limonium (Plumbaginaceae) species from the Balearic Islands and the western Iberian Peninsula

Somatic chromosome numbers, conventional karyotype features and idiograms are reported for 27 Limonium species inhabiting the Western Mediterranean basin (Iberian Peninsula and the Balearic Islands). The chromosome numbers of Limonium barceloi (2 n  = 36), L. ejulabilis (2 n  = 24), L. inexpectans (2 n  = 26), L. interjectum (2 n  = 24), and L. scopulorum (2 n  = 25) were determined for the first time. In addition, new aneuploid and/or polyploid cytotypes are reported in L. alcudianum (2 n  = 26), L. bonafei (2 n  = 26), L. camposanum (2 n  = 26) , L. companyonis (2 n  = 26), L. dufourii (2 n  = 26), L. geronense (2 n  = 36), L. marisolii (2n = 54), L. migjornense (2 n  = 50), and L. pseudodictyocladon (2 n  = 16). A group of polyploid species showed karyotypes comprising homologous chromosomes in groups of three ( L. antonii-llorensii, L. ejulabilis, L. interjectum, L. virgatum, and L. wiedmanii ) , four ( L. geronense ), or six ( L. marisolii ), which suggests an autopolyploid origin. Other polyploid species were characterized by the presence of two different chromosome sets ( x  = 8 and x  = 9) in the genome. The species L. alcudianum , L . bonafei , L. camposanum , L. companyonis , L. dufourii , L. gibertii , L. girardianum , L. inexpectans , L. leonardi-llorensii , L. magallufianum , L. migjornense , L. minoricense , and L. scopulorum showed various combinations of paired and unpaired x  = 8 and x  = 9 chromosome sets, suggesting that they are allopolyploids. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 257–272.     

Specific interactions of the L10(L12)4 ribosomal protein complex with mRNA, rRNA, and L11

Large ribosomal subunit proteins L10 and L12 form a pentameric protein complex, L10(L12) 4, that is intimately involved in the ribosome elongation cycle. Its contacts with rRNA or other ribosomal proteins have been only partially resolved by crystallography. In Escherichia coli, L10 and L12 are encoded from a single operon for which L10(L12) 4 is a translational repressor that recognizes a secondary structure in the mRNA leader. In this study, L10(L12) 4 was expressed from the moderate thermophile Bacillus stearothermophilus to quantitatively compare strategies for binding of the complex to mRNA and ribosome targets. The minimal mRNA recognition structure is widely distributed among bacteria and has the potential to form a kink-turn structure similar to one identified in the rRNA as part of the L10(L12) 4 binding site. Mutations in equivalent positions between the two sequences have similar effects on L10(L12) 4-RNA binding affinity and identify the kink-turn motif and a loop AA sequence as important recognition elements. In contrast to the larger rRNA structure, the mRNA apparently positions the kink-turn motif and loop for protein recognition without the benefit of Mg (2+)-dependent tertiary structure. The mRNA and rRNA fragments bind L10(L12) 4 with similar affinity ( approximately 10 (8) M (-1)), but fluorescence binding studies show that a nearby protein in the ribosome, L11, enhances L10(L12) 4 binding approximately 100-fold. Thus, mRNA and ribosome targets use similar RNA features, held in different structural contexts, to recognize L10(L12) 4, and the ribosome ensures the saturation of its L10(L12) 4 binding site by means of an additional protein-protein interaction.     

Residue L143 of the foot-and-mouth disease virus leader proteinase is a determinant of cleavage specificity

The foot-and-mouth disease virus (FMDV) leader proteinase (L(pro)) self-processes inefficiently at the L(pro)/VP4 cleavage site LysLeuLys*GlyAlaGly (* indicates cleaved peptide bond) when the leucine at position P2 is replaced by phenylalanine. Molecular modeling and energy minimization identified the L(pro) residue L143 as being responsible for this discrimination. The variant L(pro) L143A self-processed efficiently at the L(pro)/VP4 cleavage site containing P2 phenylalanine, whereas the L143M variant did not. L(pro) L143A self-processing at the eIF4GII sequence AspPheGly*ArgGlnThr was improved but showed more-extensive aberrant processing. Residue 143 in L(pro) is occupied only by leucine and methionine in all sequenced FMDV serotypes, implying that these bulky side chains are one determinant of the restricted specificity of L(pro).     

Some tropical African Lobeliaceae. Chromosome numbers, new taxa and comments on taxonomy and nomenclature

Chromosome numbers of 21 taxa in Lobelia L. and Cyphia Berg, are reported, the majority being new records. 2n = 18 in Cyphia is a new generic report. The new species Lobelia paludigena Thulin (Zaire), L. kundelungensis Thulin (Zaire), L. cheranganiensis Thulin (Kenya) and L. corniculata Thulin (Swaziland and Natal) are described. The distributions of these species, as well as of L. thermalis Thunb., are mapped. L. kalobaënsis E. Wimm. ex Thulin is validated. The new combinations L. trullifolia Hemsl. ssp. delicatula (Compton) Thulin and L. flaccida (Presl) A. DC. ssp. gnmvikii (T. C. E. Fries) Thulin are made. Typifications are provided for the following names: L. stuhlmannii Schweinf. ex Stuhlm., L. gregoriana Bak. f., L. fervens Thunb., L. anceps L. f. and L. depressa L. f.