DNA/PEI/Alginate polyplex as an efficient<Emphasis Type="Italic">in vivo</Emphasis> gene delivery system

A novel non-viral gene delivery system comprised of a DNA/PEI/Alginate (DPA) polyplex was prepared and assessedin vitro andin vivo. Coating the positively charged DNA/PEI (DP) complex with a polyanion resulted in a high level ofin vitro reporter gene transfection in the presence of 50 vol% serum due to the minimized cytotoxicity of PEI and the reduced nonspecific interactions with serum components. Among the tested anionic polymers, which included sodium alginate, poly(methacrylic acid) and poly(acrylic acid), the sodium alginate showed the highest gene transfection efficiency. The DPA polyplex also showed a reduced level of erythrocyte aggregation in target cells when compared with the DP complex. According toin vivo studies in which reporter genes encoding green fluorescent protein (GFP) and luciferase were used, injection of the DPA polyplex into tumor cells in six week old female C57/BL6 mice resulted in a much higher level of GFP expression and approximately 7 fold higher luciferase expression than treatment with the DP complex. Taken together, these results demonstrated that the anionic alginate coating of the DP complex contributed to efficient gene deliveryin vitro andin vivo.     

Solubilization and characterization of a galacturonosyltransferase that synthesizes the pectic polysaccharide homogalacturonan

Polygalacturonate 4-α-galacturonosyltransferase (PGA-GalAT), the glycosyltransferase that synthesizes the plant cell wall pectic polysaccharide homogalacturonan, has previously been identified and partially characterized in tobacco membranes. Membrane bound PGA-GalAT catalyzes the transfer of galacturonic acid from UDP-galacturonic acid (UDP-GalA) onto an endogenous acceptor to produce polymeric homogalacturonan ( Doong et al. (1995) Plant Physiol. 109, 141 –152). It is shown here that a galacturonosyltransferase is solubilized from tobacco membranes with a HEPES buffer, pH 6.8, containing 40 mM CHAPS and 2 mM EDTA. The solubilized galacturonosyltransferase was identified as putative PGA-GalAT because it transfered [¹⁴C]GalA from UDP-[¹⁴C]GalA onto exogenous homogalacturonan acceptors with degrees of polymerization (DP) of ≥ 10. Maximal solubilized PGA-GalAT activity in the presence of 0.9 μM UDP-[¹⁴C]GalA required approximately 125 μM exogenous homogalacturonan acceptor [e.g. oligogalacturonide (OGA) of DP 15]. Solubilized PGA-GalAT was active over a broad pH range of 6.3–7.8, and had an apparent K_m for UDP-GalA of 37 μM and a V_max of 290 pmol min^–1 mg^–1 protein. Approximately 44% of the PGA-GalAT activity in detergent-dispersed membranes, corresponding to 21% of the PGA-GalAT activity in intact membranes, was solubilized. PGA-GalAT solubilized with 40 mM CHAPS was shown, by exopolygalacturonase treatment in combination with size exclusion and high performance anion exchange chromatographies, to add a single α-1,4-linked galacturonic acid residue onto an OGA exogenous acceptor of DP 15 to yield an OGA product of DP 16. The significance of the apparent lack of processivity of the solubilized PGA-GalAT is discussed.     

Isolation and Crystallization of Microbial Alkaline Protease Inhibitor,S-SI

S–SI, an microbial alkaline protease inhibitor, was produced in the culture broth of Streptomyces albogriseolus S–3253. S–SI was isolated from culture filtrate by salting out with ammonium sulfate, column chromatographies on DEAE-cellulose and Sephadex G–100. S–SI was also isolated by pH adjustment of the effluent from DEAE-cellulose column.

Crystallization of S–SI was carried out, and two distinct shaped crystals, needle shaped and rhombic crystal, were obtained. Homogeneity of these crystals were identified by polyacrylamide disc electrophoresis at various pHs.

S–SI retained its perfect inhibitory activity after treatment at 37°C for 25 hr in the pH range from 3 to 10, and 100°C for 10 min in the pH range from 4 to 6.

From the examination of molecular weight determination with Sephadex G–100, the molecular weight of S–SI was decided to be about 27,000.

S–SI was found to be highly specific towards microbial alkaline proteases.     

Purification and Some Properties of Acidocin 8912, a Novel Bacteriocin Produced by Lactobacillus acidophilus TK8912

Acidocin 8912, a bacteriocin produced by Lactobacillus acidophilus TK8912, was purified by ammonium sulfate fractionation and successive chromatographies on CM-cellulose, Sephadex G-50, Sephadex G-25, and reversed-phase HPLC on Aquapore RP-300. The purified acidocin 8912 migrated as a single band on SDS–PAGE. The molecular weight was estimated to be 5200 by SDS–PAGE, and 5400 by HPLC gel filtration on TSKgel G3000PW_XL. Both the amino acid composition and the N-terminal amino acid sequence analysis indicated that acidocin 8912 was a peptide composed of presumably 50 amino acids containing a Lys residue at the N-terminus. The purified acidocin 8912 showed a bactericidal effect on sensitive cells but not a bacteriolytic effect.     

Fatty acid synthesis by slices from developing leaves

Fatty acid synthesis was studied in successive leaf sections from the base to the tip of developing barley (Hordeum vulgare L.), maize (Zea mays L.), rye grass (Lolium perenne L.) and wheat (Triticum aestivium L.) leaves. The basal regions of the leaves had the lowest rates of fatty acid synthesis and accumulated small amounts of very long chain fatty acids. Fatty acid synthesis was highest in the middle leaf sections in all four plants. Linolenic acid synthesis from [1-¹⁴C]acetate was highest in the distal leaf sections of rye grass. The labelling of the fatty acids of individual lipids of rye grass was examined and it was found that [¹⁴C]linolenic acid was highest in the galactolipids. Synthesis of this acid in the galactolipids was most active in leaf segment C. Only traces of [¹⁴C]linolenic acid were ever found in phosphatidylcholine and it is concluded that this phospholipid cannot serve as a substrate for linoleic acid desaturation in rye grass. The synthesis of fatty acids was sensitive to arsenite, fluoride and the herbicide EPTC. The latter was only inhibitory towards those leaf segments which made very long chain fatty acids. Formation of fatty acids from [1-¹⁴C]acetate was also studied in chloroplasts prepared from successive leaf sections of rye grass. Chloroplasts isolated from the middle leaf sections had the highest activity. Palmitic and oleic acids were the main fatty acid products in all chloroplast preparations. Linolenic acid synthesis was highest in chlorplasts isolated from the distal leaf sections of rye grass.     

Oxidation of regenerated cellulose with NaClO2 catalyzed by TEMPO and NaClO under acid-neutral conditions

A new TEMPO-mediated oxidation with catalytic amounts of TEMPO and NaClO, and NaClO₂ as the primary oxidant under aqueous conditions at pH 3.5–6.8 was used to prepare water-soluble β-(1 → 4)-linked polyglucuronic acid Na salts (cellouronic acids, CUAs) with high molecular weight in good yield. When regenerated cellulose with original degree of polymerization (DP) of 680 was oxidized by the 4-acetamide-TEMPO/NaClO/NaClO₂ system at pH 5.8 and 40 °C for 3 days, CUA with weight average DP (DPw) of 490 was obtained quantitatively. No peaks other than six signals from β-(1 → 4)-linked anhydroglucuronic acid units of CUA were detected in the solution-state ¹³C NMR spectra of the oxidized products. Although the oxidized product prepared under the above conditions contained about 20% unoxidized cellulose particles, the non-CUA fraction was separable from CUAs by filtration or salt precipitation. The DPw values and yields of CUAs after the filtration or salt precipitation treatment were 250–380 and 45–71%, respectively.     

Interaction between C18 fatty acids and DOPE PEG2000 in Langmuir monolayers: effect of degree of unsaturation

In this study, we address the effect of the cis-double bond in 1,2-dioleoyl-sn-glycero-3-phosphoethanolamide-N-[methoxy(polyethylene glycol)-2000, DOPE PEG2000 (DP), on the Langmuir monolayer of C18 fatty acids—namely, stearic acid (SA), oleic acid (L1), linoleic acid (L2), and linolenic acid (L3)—with the same head group but different degrees of saturation on their hydrocarbon chains. Negative values of Gibbs free energy of mixing (ΔG _mix) were obtained throughout the investigated ranges of the unsaturated C18 fatty-acid (L1, L2 and L3) mixed systems, indicating that very strong attractions occurred between molecules in the monolayers. The bend and kink effects from the cis-double bond(s) in the hydrocarbon chain affected the membrane fluidity and molecular packing in the monolayers, which resulted in a greater interaction between unsaturated C18 fatty acids and DP. The most thermodynamically stable mole composition of unsaturated C18 fatty acids to DP was observed at 50:1; this ratio is suggested to be the best mole ratio and will be subsequently used to prepare DP–C18 fatty-acid nanoliposomes. The presence of cis-double bonds in both hydrocarbon chains of DOPE in DP also created an imperfection in the membrane structure of lipid-drug delivery systems, which is expected to enhance lipid-based systems for antibody conjugation and drug encapsulation.     

Expression of a phenylcoumaran benzylic ether reductase-like protein in the ovules of <Emphasis Type="Italic">Gossypium hirsutum</Emphasis>

Two dimensional polyacrylamide gel electrophoresis (2D-PAGE) was used to identify differentially expressed proteins in wild-type (DP 5690) and fiberless (SL 1-7-1) cotton ovules. One protein, designated V2 was unique to ovules of the fiber producing DP 5690 line. The protein was purified from 2D-PAGE of 4 d post anthesis DP 5690 ovules and partially sequenced. The short amino acid sequence was nearly identical to the deduced amino acid sequence for cotton phenylcoumaran benzylic ether reductase (PCBER) protein. A consensus sequence was assembled from ESTs encoding cotton PCBER genes, primers were designed, and a full length gene was amplified from plasmid DNA from a 72 h etiolated cotton cotyledon library. The polymerase chain reaction generated a 950 bp product with unique EcoRI (5′) and (3′) KpnI restriction sites for directional insertion into the expression vector pPICZA. Nucleotide sequencing was performed, and the full length coding region was 924 bp encoding a protein of 308 amino acids. The molecular mass and pI measured (2D PAGE) were similar to the theoretical protein.     

Purification of branched-chain amino acid aminotransferase from <Emphasis Type="Italic">Helicobacter pylori</Emphasis> NCTC 11637

Summary. Branched-chain amino acid aminotransferase was purified by several column chromatographies from Helicobacter pylori NCTC 11637, and the N-terminal amino acid sequence was analyzed. The enzyme gene was sequenced based on a putative branched-chain amino acid aminotransferase gene, ilvE of H. pylori 26695, and the whole amino acid sequence was deduced from the nucleotide sequence. The enzyme existed in a homodimer with a calculated subunit molecular weight (MW) of 37,539 and an isoelectric point (pI) of 6.47. The enzyme showed high affinity to 2-oxoglutarate (K _m = 0.085 mM) and L-isoleucine (K _m = 0.34 mM), and V _max was 27.3 μmol/min/mg. The best substrate was found to be L-isoleucine followed by L-leucine and L-valine. No activity was shown toward the D-enantiomers of these amino acids. The optimal pH and temperature were pH 8.0 and 37 °C, respectively.     

The Preparation and Geometrical Isomerism of Substituted α-Methylthio-Cinnamic Acids

α-Methylthio-cinnamic acid and its substituted analogues (III) were synthesized from their respective β-aryl-α-thiopyruvic acids (II). In connection with the study on the tautomeric ene-thiol structure of β-aryl-α-thiopyruvic acids (II), 4-arylidenerl,3-oxathiolan-5-one (IV) were prepared from compounds II.     

Preparation and Isolation of Oligogalacturonic Acids and Their Biological Effects in Cockscomb (Celosia argentea L.) Seedlings

A mixture of oligogalacturonic acids, the partial degradation substances of polygalacturonic acid, promoted shoot growth in cockscomb (Celosia argentea L.) seedlings, which generally had a high sensitivity for growth-promoting substances. The effect of the mixture of oligogalacturonic acids on shoot growth of cockscomb was higher than that of the polygalacturonic acid at concentrations above 30 ppm. These oligomers were loaded onto an anion exchange column, DEAE Sephadex A-25, and separated into individual oligomer sizes using the NH4HCO3 eluent system. This separation method has the advantage of using NH4HCO3 as the eluent solution; NH4HCO3 in the sample solution is effectively removed by lyophilization. Each of the isolated oligogalacturonic acids gave a single band on a fluorophore-assisted carbohydrate electrophoresis (FACE), and they showed the m/z value which corresponded to their molecular ion peaks [M-H]- on a fast atom bombardment mass spectrometry (FAB-MS) analysis. These results showed that the successive chromatography method used in this study is well suited for the preparation of oligogalacturonic acid for the plant growth test. Furthermore, we showed that the effective degree of polymerization (DP) of oligogalacturonic acid was around 8 on shoot growth of cockscomb seedlings, and the effects of both smaller and larger oligogalacturonic acids were slightly lower than that of octa-galacturonide. Octa-galacturonide promoted shoot growth of cockscomb at concentrations above 10 mM, and showed a 66% promotion at the most effective concentration of 300 mM. Root growth was slightly inhibited at concentrations above 300 mM. These results suggest that DP around 8 of oligogalacturonic acids has the function to control shoot growth in cockscomb as a growth-promoting substance.     

Molecular configuration of amylose and its complexes in aqueous solutions. Part II. Relation between the DP of helical segments of the amylose–iodine complex and the equilibrium concentration of free iodine

The iodine which is added to an aqueous amylose solution is bound only partly by the amylose while forming the blue complex and partly remains free. The equilibrium normality of the free and the bound iodine at half-saturation of amylose by iodine is designated as [I_f]_v and [I_b]_w, respectively. The stability of the poly iodine chain formed within the axis of amylose helices depends on its length, i.e., indirectly on the DP of the amylose helices: the greater this stability, the lower the [I_f]_v value. The amylose molecule consists of helical segments. Such a molecule may behave as a random coil. The average length of the helical segments in freshly prepared amylose-iodine complexes depends on temperature, pH, iodide concentration, the presence of other complex-forming agents, and the DP of the amylose. This latter factor is investigated in the present paper. By the aid of an automatically recording photometrictitrating device the coherent values of [I_b] and [I_f] were determined. Plotting these values against DP _n for mechanochemically degraded as well as for periodateo-xidized amyloses resulted in curves consisting of two linear sections. The break of the curves occurred between DP _n 110 and 130. It was concluded that below DP _n = 100 the DP of helical segments (= sDP _n) is identical to the DP _n of the total molecule, i.e., the molecule consists of only a single, relatively stiff helix. Above this limit the molecule contains several helical segments. The DP of these helical segments can be calculated as follows: sDP _n = 141.1 ? 10.2 × 10⁵[I_f]_v. This equation is considered to be valid for 0.5–0.6 mg. amylose in 100 ml. 0.1N HCl at 20°C., λ = 650 mμ, euuvet diameter 3.4 cm., the feed rate of the iodate-iodide titrating solution (in acid medium resulting in a 5 × 10^?3N I₂ solution with a molar iodide to iodine ratio of 1.5) is 0.4ml./min. Amylose molecules of, e.g., DP ⁿ = 1380 consist of an average of 11.4 segments having a DP of about 120 and consisting of an average of 15–18 helical turns.     

Preparation and Isolation of Oligogalacturonic Acids and Their Biological Effects in Cockscomb (Celosia argentea L.) Seedlings

A mixture of oligogalacturonic acids, the partial degradation substances of polygalacturonic acid, promoted shoot growth in cockscomb (Celosia argentea L.) seedlings, which generally had a high sensitivity for growth-promoting substances. The effect of the mixture of oligogalacturonic acids on shoot growth of cockscomb was higher than that of the polygalacturonic acid at concentrations above 30 ppm. These oligomers were loaded onto an anion exchange column, DEAE Sephadex A-25, and separated into individual oligomer sizes using the NH4HCO3 eluent system. This separation method has the advantage of using NH4HCO3 as the eluent solution; NH4HCO3 in the sample solution is effectively removed by lyophilization. Each of the isolated oligogalacturonic acids gave a single band on a fluorophore-assisted carbohydrate electrophoresis (FACE), and they showed the m/z value which corresponded to their molecular ion peaks [M-H]- on a fast atom bombardment mass spectrometry (FAB-MS) analysis. These results showed that the successive chromatography method used in this study is well suited for the preparation of oligogalacturonic acid for the plant growth test. Furthermore, we showed that the effective degree of polymerization (DP) of oligogalacturonic acid was around 8 on shoot growth of cockscomb seedlings, and the effects of both smaller and larger oligogalacturonic acids were slightly lower than that of octa-galacturonide. Octa-galacturonide promoted shoot growth of cockscomb at concentrations above 10 mM, and showed a 66% promotion at the most effective concentration of 300 mM. Root growth was slightly inhibited at concentrations above 300 mM. These results suggest that DP around 8 of oligogalacturonic acids has the function to control shoot growth in cockscomb as a growth-promoting substance.     

StructureActivity Relationships of Antimicrobial Gallic Acid Derivatives from Pomegranate and Acacia Fruit Extracts against Potato Bacterial Wilt Pathogen

Bacterial wilts of potato, tomato, pepper, and or eggplant caused by Ralstonia solanacearum are among the most serious plant diseases worldwide. In this study, the issue of developing bactericidal agents from natural sources against R. solanacearum derived from plant extracts was addressed. Extracts prepared from 25 plant species with antiseptic relevance in Egyptian folk medicine were screened for their antimicrobial properties against the potato pathogen R. solancearum by using the disc‐zone inhibition assay and microtitre plate dilution method. Plants exhibiting notable antimicrobial activities against the tested pathogen include extracts from Acacia arabica and Punica granatum. Bioactivity‐guided fractionation of A. arabica and P. granatum resulted in the isolation of bioactive compounds 3,5‐dihydroxy‐4‐methoxybenzoic acid and gallic acid, in addition to epicatechin. All isolates displayed significant antimicrobial activities against R. solanacearum (MIC values 0.5–9 mg/ml), with 3,5‐dihydroxy‐4‐methoxybenzoic acid being the most effective one with a MIC value of 0.47 mg/ml. We further performed a structure–activity relationship (SAR) study for the inhibition of R. solanacearum growth by ten natural, structurally related benzoic acids.     

Heterogenous Degradation of Myofibrillar Proteins

Pectic substances were extracted from the vegetables with oxalate buffer of pH 4.25 and, after saponification, fractionated into two components, weakly acidic pectic polysaccharide (WAP) and pectic acid, by DEAE-cellulose and Sephadex G-100 chromatographies. The galacturonic acid content (17.3~25.8%) of WAPs was much lower than that of pectic acids, though the neutral sugar compositions of both pectic substances were almost the same. The arabinose-galactose side chains were found to be very long or highly branched in WAPs compared with those in pectic acids.

All the WAPs were appreciably hydrolyzed by exo- and endopolygalacturonases. The limited-degradation products (the residual polysaccharides; i.e., the rhamnogalacturonan segments) obtained by endopolygalacturonase from both WAPs and pectic acids showed a similar behavior on Sephadex G-100 and Sepharose CL-4B gel filtrations; each of the rhamnogalacturonan segments was eluted in the void volume of the Sephadex G-100 column. From these results, we concluded that WAPs are probably an inherent pectic component of the cell walls of the vegetables.     

Screening,Purification and Properties of a Specific Antiphage Substance,AFS, against Filamentous Phage of Escherichia coli

We have made screening for antiphage antibiotics using an assay system of a male-specific filamentous phage, fl, and Escherichia coli as its host, and found a proteinous active substance named AFS (anti-filamentous phage substance) which was produced by an Actinomyces belonging to the group of Streptomyces lavendulae. It was purified from the filtered broth of the strain by ammonium sulfate precipitation and chromatographies of SP-Sephadex, CM-Sephadex and Sephadex G–50. The purified preparation was judged to be homogeneous by several column chromatographies and electrophoresis. Its molcular weight was about 5100 and isoelectric point was pH 9.9. Fourty two residues of amino acids, rich in the hydrophobic ones, were contained in one mole of AFS, but no carbohydrate was detected.     

Isolation of the Teichoic Acid of Bacillus Subtilis 168 by Affinity Chromatography

A column of insoluble concanavalin A was prepared by coupling the protein to cyanogen bromide-activated Sepharose. When autolysates of Bacillus subtilis 168 cell walls were passed over the column, the alpha glucosylated teichoic acid component of the cell wall was retained. The teichoic acid could be eluted with dilute alpha-methylglucopyranose. The teichoic acid prepared by affinity chromatography from cell wall autolysates had a higher sedimentation rate than teichoic acids obtained by conventional methods.

Several authors have shown that concanavalin A (con A) forms complexes with alpha-glucosylated teichoic acids^1–3. Doyle and Birdsell¹ found that the teichoic acid of Bacillus subtilis 168 (trp C2) would precipitate with con A at neutral pH in dilute buffer. The formation of a precipitate was inhibited by sugars which bind to the active site of con A. This observation suggested that it should be possible to purify the teichoic acid by affinity chromatography using insoluble con A as the affinity probe. Lloyd⁴ and Donnelly and Goldstein⁵ have successfully employed insoluble con A to purify polysaccharides and glycoproteins. In this communication, we describe conditions for the rapid purification of the alpha-glucosylated teichoic acid of B. subtilis 168. The teichoic acid prepared by this procedure appears to be less degraded than teichoic acids obtained by conventional methods.     

Constitutional Amino Acids of the Antibiotic YA–56

Acid hydrolysis of the antibiotic YA-56 X (Zorbamycin) and Y belonging to the phleomycin-bleomycin group was carried out and the following constitutional amino acids were isolated from the hydrolyzate of YA–56 X: β-Amino-β-(4-amino-6-carboxy-5-methylpyrimidine-2-yl)- propionic acid, β-aminoalanine, L-erythro-β-hydroxyhistidine and 3 unidentified amino acids. Though the former 3 amino acids were known to be constituents of phleomycins and bleomycins, the latter three were not found in phleomycins and bleomycins. YA–56 Y gave one more unidentified amino acid.

Furthermore, isolation of β-alanine and 2-acetylthiazole-4-carboxylic acid from the hydrolyzate indicated the presence of 2-(2-(2-aminoethyl)-Δ²-thiazoline-4-yl)-thiazole-4-carboxylic acid in YA–56 X and Y as in phleomycins.     

Substrate Specificity of Streptomyces β-Xylanase toward Glucoxylan

To discover the specificity of Streptomyces β-xylanase toward xylan having glucose stubs, glucoxylan was prepared by the hydrogenation of cotton-seed cake glucuronoxylan. The glucoxylan was hydrolyzed by the β-xylanase of Streptomyces olivaceoviridis E-86, and three kinds of glucoxylo-oligosaccharides were isolated from the hydrolysate by chromatographies on a charcoal column, preparative paper partition, and a Toyopearl HW-40F column. The isolated oligosaccharides had the structures of 2³-α-glucopyranosylxylo-triose, 2³-α-(4–O-methyl-glucopyranosyl)xylotriose and 2⁴-α-glucopyranosylxylotetraose. From the structure of the above oligosaccharides and the results of our previous studies, we suggest that the specificity of Streptomyces β-xylanase toward glucose stubs is the same as that toward glucuronic acid stubs, but differs considerably from that toward arabinose stubs.     

Microwave assisted rapid method for hydrolysis of sodium alginate for M/G ratio determination

A rapid one-pot method for hydrolysis of sodium alginate for determining M/G ratio has been developed under mild conditions, using microwave irradiation. Poly-mannuronic acid (PMA) and poly-guluronic acid (PGA) ratio was determined (M/G 0.38), which was similar to that (M/G 0.39) obtained by the conventional method, using sodium alginate of Sigma as reference sample for bench marking. For validation of the method PMA and PGA were characterized by density, porosity, viscosity, optical rotation measurements, ¹³C NMR, FT-IR, thermogravimetric analysis (TGA), X-ray diffraction, circular dichroism (CD), molar mass distribution (GPC) and scanning electron microscopy (SEM).