Correlation between Lack of Receptacle Growth in Response to Auxin and Accumulation of a Specific Polypeptide in a Strawberry (Fragaria ananassa Duch.) Variant Genotype

Receptacle growth in strawberry (Fragaria ananassa Duch. cv.Ozark Beauty) occurred after either pollination or auxin treatment.In a strawberry variant genotype (Washington State UniversitySelection No. 12/13), pollination did not lead to receptaclegrowth but application of -naphthaleneacetic acid (NAA) at anthesisresulted in normal receptacle growth. The receptacles of OzarkBeauty retained their ability to respond to auxin at least upto 36 days after anthesis. However, delay of auxin applicationto the receptacles of the variant genotype resulted in decreasedauxin-responsive growth and auxin application after the 10thday of anthesis led to very little growth. The loss of auxin-responsivegrowth of the receptacle of the variant genotype was not associatedwith any loss of auxin binding activity of receptacle membranes.If auxin was not supplied to the receptacles of the variantgenotype at anthesis, the receptacles did not grow and a polypeptideof 52,000 M_r accumulated. Application of NAA to the receptaclesof the variant genotype at anthesis or on the fifth day afteranthesis resulted in the growth of the receptacle and the 52,000M_r polypeptide did not accumulate. Application of NAA to thereceptacles of the variant genotype on the 10th or the 15thday after anthesis led to very little growth of the receptacleand the 52,000 M_r polypeptide accumulated to high levels. Theseresults suggested a correlation between the lack of receptaclegrowth in response to auxin and accumulation of the 52,000 M_rpolypeptide. ¹ Current adress: The Institute of Applied Research, Ben GurionUniversity of the Negev, Beer-Sheva, Israel. (Received August 6, 1984; Accepted December 11, 1984)     

Mutations in two cysteine-histidine-rich clusters in adenovirus type 2 DNA polymerase affect DNA binding.

Several point and linker insertion mutations in two Cys-His-rich regions of adenovirus (Ad) DNA polymerase (Pol) gene have been expressed in recombinant vaccinia virus. The resulting mutant enzymes were analyzed in vitro for their effects on DNA synthesis activity, on Ad-specific initiation assays, on gel shifts of Ad origin sequences, and on interactions with adenovirus preterminal protein (pTP) and nuclear factor I (NFI). In general, mutants in downstream Cys-His sequences had a pronounced effect in these assays. Mutants in the upstream Cys-His region had a moderate effect on DNA synthesis and elongation but failed to make dCMP-pTP initiation complexes and failed to make specific shifted complexes in a gel retardation assay. These mutants could still bind to pTP and NFI in a coimmunoprecipitation experiment, suggesting that this upstream Cys-His region of Ad Pol is involved either in specific Ad DNA origin binding or in nonspecific DNA binding. Changing residues within Cys doublets in the downstream Cys-His region had pronounced effects on many Ad Pol functions such as DNA synthesis, DNA binding, and in vitro initiation; however, these mutants showed little reduction in binding to pTP and NFI; mutants at other cysteines or histidines within this region of Ad Pol did not appear to have an effect on enzyme function. This observation suggests that the downstream Cys-His region of Ad Pol is important for DNA binding and might fold into a Zn finger motif.     

A covalently bound photoisomerizable agonist. Comparison with reversibly bound agonists at electrophorus electroplaques

After disulphide bonds are reduced with dithiothreitol, trans-3- (α-bromomethyl)-3’-[α- (trimethylammonium)methyl]azobenzene (trans-QBr) alkylates a sulfhydryl group on receptors. The membrane conductance induced by this “tethered agonist” shares many properties with that induced by reversible agonists. Equilibrium conductance increases as the membrane potential is made more negative; the voltage sensitivity resembles that seen with 50 [mu]M carbachol. Voltage- jump relaxations follow an exponential time-course; the rate constants are about twice as large as those seen with 50 μM carbachol and have the same voltage and temperature sensitivity. With reversible agonists, the rate of channel opening increases with the frequency of agonist-receptor collisions: with tethered trans-Qbr, this rate depends only on intramolecular events. In comparison to the conductance induced by reversible agonists, the QBr-induced conductance is at least 10-fold less sensitive to competitive blockade by tubocurarine and roughly as sensitive to “open-channel blockade” bu QX-222. Light-flash experiments with tethered QBr resemble those with the reversible photoisomerizable agonist, 3,3’,bis-[α-(trimethylammonium)methyl]azobenzene (Bis-Q): the conductance is increased by cis {arrow} trans photoisomerizations and decreased by trans {arrow} cis photoisomerizations. As with Bis-Q, ligh-flash relaxations have the same rate constant as voltage-jump relaxations. Receptors with tethered trans isomer. By comparing the agonist-induced conductance with the cis/tans ratio, we conclude that each channel’s activation is determined by the configuration of a single tethered QBr molecule. The QBr-induced conductance shows slow decreases (time constant, several hundred milliseconds), which can be partially reversed by flashes. The similarities suggest that the same rate-limiting step governs the opening and closing of channels for both reversible and tethered agonists. Therefore, this step is probably not the initial encounter between agonist and receptor molecules.     

Structural and sequence comparisons of bacterial enoyl-CoA isomerase and enoyl-CoA hydratase

Crystal structures of enoyl-coenzyme A (CoA) isomerase from Bosea sp. PAMC 26642 (BoECI) and enoyl-CoA hydratase from Hymenobacter sp. PAMC 26628 (HyECH) were determined at 2.35 and 2.70 Å resolution, respectively. BoECI and HyECH are members of the crotonase superfamily and are enzymes known to be involved in fatty acid degradation. Structurally, these enzymes are highly similar except for the orientation of their C-terminal helix domain. Analytical ultracentrifugation was performed to determine the oligomerization states of BoECI and HyECH revealing they exist as trimers in solution. However, their putative ligand-binding sites and active site residue compositions are dissimilar. Comparative sequence and structural analysis revealed that the active site of BoECI had one glutamate residue (Glu135), this site is occupied by an aspartate in some ECIs, and the active sites of HyECH had two highly conserved glutamate residues (Glu118 and Glu138). Moreover, HyECH possesses a salt bridge interaction between Glu98 and Arg152 near the active site. This interaction may allow the catalytic Glu118 residue to have a specific conformation for the ECH enzyme reaction. This salt bridge interaction is highly conserved in known bacterial ECH structures and ECI enzymes do not have this type of interaction. Collectively, our comparative sequential and structural studies have provided useful information to distinguish and classify two similar bacterial crotonase superfamily enzymes.     

Pontibacter jeungdoensis sp. nov., isolated from a solar saltern in Korea

A Gram-staining-negative, rod-shaped and red-pigmented bacterial strain, HMD3125^T, was isolated from a solar saltern in Jeungdo, Republic of Korea. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HMD3125^T formed a lineage within the genus Pontibacter and was similar to Pontibacter salisaro (96.1%) and P. korlensis (95.3%). The major fatty acids of strain HMD3125^T were summed feature 4 (comprising iso-C_17:1 I and/or anteiso-C_17:1 B; 30.4%), iso-C_15:0 (20.4%) and iso-C_17:0 3OH (17.2%). The polar lipid profile of HMD3125^T consisted of the phosphatidylethanolamine, four unidentified polar lipids, unidentified phospholipid, unidentified aminolipid and unidentified aminophospholipid. Strain HMD3125^T contained MK-7 as the predominant menaquinone and sym-homospermidine as the major polyamine. The DNA G+C content of strain HMD3125^T was 45.6 mol%. Strain HMD3125^T assigned as a novel species in the genus Pontibacter, for which the name Pontibacter jeungdoensis sp. nov. is proposed. The type strain is HMD3125^T (=KCTC 23156^T =CECT 7710^T).     

PTP1B inhibitory effects of tridepside and related metabolites isolated from the Antarctic lichen Umbilicaria antarctica

The selective inhibition of PTP1B has been widely recognized as a potential drug target for the treatment of type 2 diabetes and obesity. In the course of screening for PTP1B inhibitory natural products, the MeOH extract of the dried sample of the Antarctic lichen Umbilicaria antarctica was found to exhibit significant inhibitory effect, and the bioassay-guided fractionation and purification afforded three related lichen metabolites 1-3. Compounds 1-3 were identified as gyrophoric acid (1), lecanoric acid (2), and methyl orsellinate (3) mainly by analysis of NMR and MS data. These compounds inhibited PTP1B activity with 50% inhibitory concentration values of 3.6 ± 0.04 μM, 31 ± 2.7 μM, and 277 ± 8.6 μM, respectively. Furthermore, the kinetic analysis of PTP1B inhibition by compound 1 suggested that the compound inhibited PTP1B activity in a non-competitive manner.     

Identification and characterization of proteins isolated from microvesicles derived from human lung cancer pleural effusions

Microvesicles (MVs, also known as exosomes, ectosomes, microparticles) are released by various cancer cells, including lung, colorectal, and prostate carcinoma cells. MVs released from tumor cells and other sources accumulate in the circulation and in pleural effusion. Although recent studies have shown that MVs play multiple roles in tumor progression, the potential pathological roles of MV in pleural effusion, and their protein composition, are still unknown. In this study, we report the first global proteomic analysis of highly purified MVs derived from human nonsmall cell lung cancer (NSCLC) pleural effusion. Using nano‐LC–MS/MS following 1D SDS‐PAGE separation, we identified a total of 912 MV proteins with high confidence. Three independent experiments on three patients showed that MV proteins from PE were distinct from MV obtained from other malignancies. Bioinformatics analyses of the MS data identified pathologically relevant proteins and potential diagnostic makers for NSCLC, including lung‐enriched surface antigens and proteins related to epidermal growth factor receptor signaling. These findings provide new insight into the diverse functions of MVs in cancer progression and will aid in the development of novel diagnostic tools for NSCLC.     

A new fused tetracyclic heterocyclic antioxidant from Serratia sp. PAMC 25557

A new fused tetracyclic heterocyclic compound, (4bR,10bR)-4b-hydroxy-10b,12-dihydrodibenzo[c,h][2,6]naphthyridine-5,11(4bH,6H)-dione (1), and a known compound, butyl 2-[(benzoyloxy)methyl]benzoate, spatozoate 2, were isolated from the broth culture of Serratia sp. PAMC 25557. The structure of 1 was determined by analyzing spectroscopic data. Compound 1 did not exhibit antimicrobial activity against Escherichia coli, Staphylococcus aureus, or Candida albicans. In addition, up to 100 μg/ml compound 1 did not show any toxicity against Artemia salina larvae. However, compound 1 showed DPPH free radical scavenging activity (IC₅₀ = 16.7 ± 0.34 μg/ml). This was the first report of spatozoate isolation from bacterial sources.     

Palatability and feeding preferences of Uresiphita maorialis (Lepidoptera: Crambidae) for three Sophora species

In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata.     

Biodeterioration of Mayan buildings at uxmal and tulum,Mexico

Uxmal and Tulum are two important Mayan sites in the Yucatan peninsula. The buildings are mainly composed of limestone and grey/black discoloration is seen on exposed walls and copious greenish biofilms on inner walls. The principal microorganisms detected on interior walls at both Uxmal and Tulum were cyanobacteria; heterotrophic bacteria and filamentous fungi were also present. A dark‐pigmented mitosporic fungus and Bacillus cereus, both isolated from Uxmal, were shown to be acidogenic in laboratory cultures. Cyanobacteria belonging to rock‐degrading genera Synechocystis and Gloeocapsa were identified at both sites. Surface analysis previously showed that calcium ions were present in the biofilms on buildings at Uxmal and Tulum, suggesting the deposition of biosolubilized stone. Apart from their potential to degrade the substrate, the coccoid cyanobacteria supply organic nutrients for bacteria and fungi, which can produce organic acids, further increasing stone degradation.