Correlation between tyrosine hydroxylase activity and catecholamine concentration or turnover in brain regions.

Tyrosine hydroxylase activity correlated significantly with norepinephrine concentration and turnover, when results from regions containing predominantly noradrenergic terminals were compared, and with dopamine concentration and turnover when results from regions containing predominantly dopaminergic terminals were compared. Regions containing dopamine or norepinephrine cell bodies were characterized by higher tyrosine hydroxylase activities as compared to regions containing mostly nerve terminals. Higher levels of tyrosine hydroxylase activity and transmitter turnover were observed in regions containing dopaminergic terminals than in regions containing norepinephrine terminals. These findings are consistent with the view that tyrosine hydroxylase activity is linked to rates of catecholamine utilization by neurons in the CNS.     

Structural features of the amplified N-myc oncogene detected by micrococcal nuclease digestion of neuroblastoma cell nuclei

The structure of chromatin containing amplified N-myc in neuroblastoma and retinoblastoma cells was investigated using micrococcal nuclease digestion of isolated nuclei. The size distribution of DNA fragments containing N-myc, produced by micrococcal nuclease digestion of nuclei, was determined and compared to that of DNA containing the structural gene for dihydrofolate reductase. A perturbation of the native structure of chromatin containing N-myc was evident from the association of N-myc with more extensively digested DNA when compared with chromatin containing dihydrofolate reductase.     

Lippia dulcis shoot cultures as a source of the sweet sesquiterpene hernandulcin

The axenic shoot culture of Lippia dulcis Trev., Verbenaceae, was established on hormone-free Murashige-Skoog solid medium containing 3% sucrose. Shoots were cultured in various liquid or solid media. Woody Plant liquid medium was best for shoot multiplication, but the production of hernandulcin was relatively low. The highest hernandulcin content (2.9% dry wt) was obtained after 28 days of culture on Murashige-Skoog solid medium containing 2% sucrose. The addition of chitosan to the culture media enhanced the growth of shoots as well as the production of hernandulcin, especially with the liquid medium.Abbreviations MS(2%) Murashige-Skoog medium containing 2 % sucrose - MS(3%) Murashige-Skoog medium containing 3 % sucrose - 1/2MS half strength Murashige-Skoog medium containing 2% sucrose - B5 Gamborg B5 medium containing 2% sucrose - WP Woody Plant medium containing 2% sucrose     

The stability of oligodeoxyribonucleotide duplexes containing degenerate bases.

Oligodeoxyribonucleotides containing N4-methoxycytosine (mo4C), N4-methoxy-5-methylcytosine (mo4m5C) and other base-analogues were synthesised and used to compare the stabilities of duplexes containing mo4C.A and mo4C.G base pairs with those containing normal and mismatch pairs. The Tm values and other thermodynamic parameters are recorded. The otherwise identical duplexes containing a mo4C.A and a mo4C.G base pair have closely similar stabilities to each other and to the corresponding duplexes containing normal base pairs, considerably greater than the stabilities of those containing mismatch pairs. Corresponding observations are recorded in dot-blot experiments using M13 cloned DNA carrying an insert complementary to the oligonucleotides; approximate Td values are given.     

Human interferon-gamma (IFN-gamma) containing cells bear various surface phenotypic markers

We explored the population of Interferon-gamma (IFN-gamma) containing cells in order to clarify their cell surface phenotypic markers. Here we define gamma-IFN containing cells as gamma-IFN plaque forming cells (PFC). By this method, it was found that IFN-gamma containing cells consist of two cell fractions, i.e., OKT3+, OKT4+, and OKT8- cells and OKM1+ cells. Effective IFN-gamma production seems to require participation of plastic-adherent cells (presumably monocytes), while the addition of cyclosporin A (CyA) almost completely blocked generation of human IFN-gamma. To characterize Con A-stimulated IFN-gamma containing cells, we performed two-color flow cytometry using FACS IV. Most of the IFN-gamma containing cells have surface phenotypic markers for Leu3, Leu8, Leu15, HLA-DR, and IL-2 receptors, but most lack markers for Leu2 and Leu7. Interestingly, most of Leu3+ and IL-2 receptor+ cells belong to the dimly illuminating cell fractions of the IFN-gamma containing cell population. Our results indicate that IFN-gamma containing cells are heterogeneous with respect to surface phenotypic markers but the predominant IFN-gamma containing cell type is the helper T cell (OKT4+). Lastly, OK432, glycyrrhizin, and CCA (lobenzarit disodium) increase the number of IFN-gamma containing cells and are thought to be immunomodulators.     

Rheological properties of suspensions containing cross-linked starch nanoparticles prepared by spray and vacuum freeze drying methods

The rheological behavior of suspensions containing vacuum freeze dried and spray dried starch nanoparticles was investigated to explore the effect of these two drying methods in producing starch nanoparticles which were synthesized using high pressure homogenization and mini-emulsion cross-linking technique. Suspensions containing 10% (w/w) spray dried and vacuum freeze dried nanoparticles were prepared. The continuous shear viscosity tests, temperature sweep tests, the frequency sweep and creep-recovery tests were carried out, respectively. The suspensions containing vacuum freeze dried nanoparticles showed higher apparent viscosity within shear rate range (0.1-100s(-1)) and temperature range (25-90°C). The suspensions containing vacuum freeze dried nanoparticles were found to have more shear thinning and less thixotropic behavior compared to those containing spray dried nanoparticles. In addition, the suspensions containing vacuum freeze dried particles had stronger elastic structure. However, the suspensions containing spray dried nanoparticles had more stiffness and greater tendency to recover from the deformation.     

Effect of Fructose Supplementation on Sorbitol Accumulation and myolnositol Metabolism in Cultured Neuroblastoma Cells Exposed to Increased Glucose Concentrations

Aldose reductase activity is increased in neuroblastoma cells grown in media containing 30 mM fructose and/or 30 mM glucose. Neuroblastoma cells cultured in media supplemented with increased concentrations of glucose and fructose amass greater amounts of sorbitol than do cells exposed to media containing only high glucose concentrations. The increase in sorbitol content is dependent on the fructose and glucose concentration in the media. The increase in sorbitol content caused by exposing neuroblastoma cells to media containing 30 mM glucose/30 mM fructose is due to a protein synthesis sensitive mechanism and not to an alteration in the redox state. The addition of sorbinil to media containing 30 mM glucose blocks the increase in sorbitol content. In contrast, sorbinil treatment of media containing 30 mM glucose/30 mM fructose does not totally block the increase in sorbitol levels. myo-Inositol accumulation and incorporation into inositol phospholipids and intracellular myo-inositol content are decreased in cells chronically exposed to media containing 30 mM glucose or 30 mM glucose/30 mM fructose compared to cells cultured in unsupplemented media or media containing 30 mM fructose. However, maximal depletion of myo-inositol accumulation and intracellular content occurs earlier in cells exposed to media containing 30 mM glucose/30 mM fructose than in cells exposed to media supplemented with 30 mM glucose. Sorbinil treatment of media containing 30 mM glucose/30 mM fructose maintains cellular myo-inositol accumulation and incorporation into phospholipids at near normal levels. myo-Inositol content in neuroblastoma cells chronically exposed to media containing 30 mM glucose or 30 mM glucose/30 mM fructose recovers within 72 h when the cells are transferred to unsupplemented media or media containing 30 mM fructose. In contrast, the sorbitol content of cells previously exposed to media containing 30 mM glucose or 30 mM glucose/30 mM fructose then transferred into media containing 30 mM fructose remains elevated compared to the sorbitol content of cells transferred into unsupplemented media. These data suggest that fructose may be activating or increasing sorbinil-resistant aldose reductase activity as well as partially blocking sorbitol dehydrogenase activity. The presence of increased concentrations of fructose in combination with increased glucose levels may enhance alterations in cell metabolism and properties due to increased sorbitol levels.     

Protein-RNA crosslinking in Escherichia coli 30S ribosomal subunits. Identification of a 16S rRNA fragment crosslinked to protein S12 by the use of the chemical crosslinking reagent 1-ethyl-3-dimethyl-aminopropylcarbodiimide.

1-ethyl-3-dimethyl aminopropylcarbodiimide (EDC) was used to cross-link 30S ribosomal proteins to 16S rRNA within the E. coli 3OS ribosomal subunit. Covalently linked complexes containing 30S proteins and 16S rRNA, isolated by sedimentation of dissociated crosslinked 30S subunits through SDS containing sucrose gradients, were digested with RNase T1, and the resulting oligonucleotide-protein complexes were fractionated on SDS containing polyacrylamide gels. Eluted complexes containing 30S proteins S9 and S12 linked to oligonucleotides were obtained in pure form. Oligonucleotide 5'terminal labelling was successful in the case of S12 containing but not of the S9 containing complex and led to identification of the S12 bound oligonucleotide as CAACUCG which is located at positions 1316-1322 in the 16S rRNA sequence. Protein S12 is crosslinked to the terminal G of this heptanucleotide.     

Lupin-seed meal (Lupinus angustifolius cv. Uniwhite) as a protein supplement to barley-based diets for growing pigs

The apparent digestibility coefficients of the energy and nitrogen of diets containing lupin-seed meal (LSM) were similar to those of diets containing fish meal, despite the comparatively high fibre content of the former.In pigs of 25–85 kg, barley-based diets containing LSM as the sole protein concentrate supported similar rates of gain and efficiency of gain as those containing mixtures of LSM and either fish meal or meat and bone meal, and at least as fast and efficient gains as those containing fish meal or meat and bone meal alone as the source of supplementary protein. However, they depressed dressing percentage. Pigs growing from 12 to 25 kg on barley diets in which up to 45% of the supplementary lysine was supplied in the form of LSM grew as well as those given diets containing various mixtures of dried blood, fish meal and skim-milk powder.     

稻瘟菌WD重复功能域中SSR的变异及其对蛋白结构的影响

含WD重复功能域的蛋白能够参与信号传导、转录调控、RNA剪切、细胞的凋亡等多种功能,在病原菌与寄主植物蛋白互作的过程中扮演着重要的角色。本研究分析了稻瘟病菌基因组中94个WD功能域基因编码区和调控区中SSR的组成、分布,并检测了7个蛋白编码区中SSR的变异及其对蛋白二级结构的影响。结果表明,WD功能域基因的编码区和调控区中都含有大量的SSR,但是SSR在这些基因的外显子区、内含子区、5’一UTR和3’一UTR区中SSR的组成和分布均不相同;编码区中三碱基和六碱基SSR分布较多,这些SSR基序大都表现为GC含量较高和其所编码的亲水性氨基酸出现的频率远远高于疏水性氨基酸的特点。且检测的7个WD功能域基因的编码区中的SSR位点均具有丰富的多态性,通过Antheprot（DPM）软件预测发现：SSR的变异对蛋白的二级结构有一定影响。这暗示着SSR的变异对致病相关基因的变异起着十分重要的作用。     

Effects of intracellular trehalose content on Streptomyces griseus spores.

The disaccharide trehalose is accumulated as a storage product by spores of Streptomyces griseus. Growth on media containing excess glucose yielded spores containing up to 25% of their dry weight as trehalose. Spores containing as little as 1% of their dry weight as trehalose were obtained during growth on media containing a limiting amount of glucose. Spores containing low levels of trehalose accumulated this sugar when incubated with glucose. The increase in trehalose content coincided with increases in spore refractility, heat resistance, desiccation resistance, and the time required for spore germination in complex media. Trehalose is accumulated by a wide variety of actinomycetes and related bacteria and may be partially responsible for their resistance properties.     

Differences in G-actin containing bound ATP or ADP: the Mg2+-induced conformational change requires ATP

The role of adenosine 5'-triphosphate (ATP) in the Mg2+-induced conformational change of rabbit skeletal muscle G-actin has been investigated by comparing actin containing bound ADP with actin containing bound ATP. As previously described [Frieden, C. (1982) J. Biol. Chem. 257, 2882-2886], N-acetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine-labeled G-actin containing ATP undergoes a time-dependent Mg2+-induced fluorescence change that reflects a conformational change in the actin. Addition of Mg2+ to labeled G-actin containing ADP gives no fluorescence change, suggesting that the conformational change does not occur. The fluorescence change can be restored on the addition of ATP. Examination of the time courses of these experiments suggests that ATP must replace ADP prior to the Mg2+-induced change. The Mg2+-induced polymerization of actin containing ADP is extraordinarily slow compared to that of actin containing ATP. The lack of the Mg2+-induced conformational change, which is an essential step in the Mg2+-induced polymerization, is probably the cause for the very slow polymerization of actin containing ADP. On the other hand, at 20 degrees C, at pH 8, and in 2 mM Mg2+, the elongation rate from the slow growing end of an actin filament, measured by using the protein brevin to block growth at the fast growing end, is only 4 times slower for actin containing ADP than for actin containing ATP.     

Laboratory and field evaluation of commercial repellent formulations against mosquitoes (Diptera: Culicidae) in Queensland, Australia

Abstract  Laboratory tests of commercial repellent formulations were conducted against Anopheles farauti Laveran, Culex annulirostris Skuse, Ochlerotatus vigilax (Skuse) and Stegomyia aegypti (L.). The majority of repellent formulations tested contain N,N ,-diethyl- 3 -methylbenzamide (also known as diethyl- m -toluamide, commonly called deet). Two formulations containing picaridin (1-piperidinecarboxylate acid, 2-(2-hydroxyethyl)-1-methylpropylester, also known as KBR 3023), one containing ethyl butylacetylaminopropionate (EBAP) and two formulations containing essential oils (e.g. Citronella oil) were also tested. In the laboratory tests, repellent formulations containing deet provided the best protection, and picaridin and EBAP also provided good protection. Citronella oil provided only limited protection. Two field trials to compare commercially available repellent formulations containing picaridin and deet against mosquitoes at Redcliffe, Queensland, were conducted. In the first, Autan Repel, containing 9.3% picaridin, RID, containing 10% deet, and Bushman Ultra, containing 80% deet in a gel, were compared. In the second, Autan Repel Army 20, containing 19.2% picaridin, OFF! Skintastic, containing 7% deet, and Aerogard, containing 12% deet, were compared. The predominant mosquito in both tests was Cx. annulirostris . Bushman provided >95% protection against all mosquitoes for at least 8 h when tests ceased. The other deet repellents also provided good protection against mosquitoes, with RID providing 5 h, Skintastic 4 h and Aerogard 2 h protection. The Autan repel (9.3% picaridin) provided >95% protection for 3 h, and Autan Repel Army (19.2% picaridin) provided 4 h protection. These studies have shown that commercial formulations of both deet and picaridin provide good protection against Cx. annulirostris , an important vector of arboviruses in Australia.     

Evolutionary relationship between the bacterial HPr kinase and the ubiquitous PEP-carboxykinase: expanding the P-loop nucleotidyl transferase superfamily

Similarities between protein three-dimensional structures can reveal evolutionary and functional relationships not apparent from sequence comparison alone. Here we report such a similarity between the metabolic enzymes histidine phosphocarrier protein kinase (HPrK) and phosphoenolpyruvate carboxykinase (PCK), suggesting that they are evolutionarily related. Current structure classifications place PCK and other P-loop containing nucleotidyl-transferases into different folds. Our comparison of both HPrK and PCK to other P-loop containing proteins reveals that all share a common structural motif consisting of an alphabeta segment containing the P-loop flanked by an additional beta-strand that is adjacent in space, but far apart along the sequence. Analysis also shows that HPrK/PCK differ from other P-loop containing structures no more than they differ from each other. We thus suggest that HPrK and PCK should be classified with other P-loop containing proteins, and that all probably share a common ancestor that probably contained a simple P-loop motif with different protein segments being added or lost over the course of evolution. We used the structure-based sequence alignment containing residues specific to HPrK/PCK to identify additional members of this P-loop containing family.     

Oligodeoxynucleotides containing 4-thiothymidine and 6-thiodeoxyguanosine as affinity labels for the Eco RV restriction endonuclease and modification methylase.

4-Thiothymidine and 6-thiodeoxyguanosine were incorporated into synthetic dodecamers containing the recognition site d(GATATC) of the enzymes Eco RV endonuclease and Eco RV methyltransferase. Upon irradiation with long wavelength UV light (340-360 nm), these oligodeoxynucleotides were photochemically crosslinked to both enzymes. The yields were up to 35% with the methyltransferase, but lower (up to 6%) with the endonuclease. Oligodeoxynucleotides containing 4-thiothymidine generally gave higher yields of crosslinking than those containing 6-thiodeoxyguanosine. Although both specific (i.e. those containing the d(GATATC) sequence) and non-specific (lacking this sequence) photoreactive oligodeoxynucleotides gave rise to crosslinked products, the use of a non-reactive, competitive substrate oligodeoxynucleotide suppressed the crosslinking, indicating that the reaction takes place at the enzymes' active sites. Oligodeoxynucleotides containing 4-thiocyanatothymidine or 6-thiocyanatodeoxyguanosine were also prepared by treatment of the title oligomers with CNBr and KCN. The dodecamers containing 4-thiocyanatothymidine were found to covalently modify both enzymes under study, with levels of crosslinking reaching up to 42% with the endonuclease and up to 12% with the methyltransferase. No crosslinking was observed with oligodeoxynucleotides containing 6-thiocyanatodeoxyguanosine.     

The Chemotaxonomy of Chinese Species of the Genus Aconitum L. (Ranunculaceae)

On the basis of biosynthsis, distribution of diterpenoid alkaloids as well as morphological evolution of Chinese species L. (Ranunculaceae), chemotaxonomy of the genus Aconitum is discussed: 1, Subgen. Lycoctonum, containing lycoctonine-type alkaloids and Subgen. Aconitum containing aconitine-type alkaloids, were probably differetiated at the early stage of evolution of the genus Aconitum and evolved respectively in their own ways. 2, In Subgen. Aconitum: (1) Ser. Bullatifolia, containing mainly atisine-, veatchine-type alkaloids, and amino, alcohol and ester base of aconitine-type, and distributed in Hengduan Mountain and Jingsha River valley, where is the centre of modern differentiation of species of Aconitum, is probably a series from which Chinese species of the genus Aconitum were derived; (2) Ser. Inflata, containing mainly aconitine, mesaconitine and bypaconitine, is an advanced group; (3) Ser. Grsndituberosa, containing mainly aconitine and songorine, is related to Ser. Bulatifolia; (4) Ser. stylosa and Ser. volubilia, containing mainly yunaconitine and other anisyl ester alkaloids form another advanced branch. 3, Ser. Tangutica and A. naviculare of Ser. Rotaundifolia, containing atisine and lactone-type alkaloids may be a specialized group in high mountains and have occurred at early stage of evolution of the genus Aconitum. 4, Subgen. Gymnaconitum, containing atisine-type alkaloids and amino alcohol of aconitine type, may als be a specialized group in high mountains. 5, A. franchetii Finet. et Gagnep. mainly containing ester bases of aconitine-typeand closed to A. chasmanthum Stapf, is best placed into Ser. Ambigua.     

Streptococcal tetracycline resistance mediated at the level of protein synthesis.

The mechanism of tetracycline resistance was examined in strains containing each of the three previously identified resistance determinants in Streptococcus spp. Uptake of tetracycline was measured in tetracycline-sensitive cells as well as in cells containing each of the three resistance determinants. In cells containing tetL, uptake was not observed. However, in sensitive cells and cells containing either tetM or tetN, tetracycline was accumulated approximately 25-fold against a concentration gradient. Furthermore, there was no evidence for modification of intracellular tetracycline recovered from sensitive, tetM, or tetN cells. Protein synthesis in extracts derived from organisms containing tetM or tetN was resistant to tetracycline. In contrast, extracts of sensitive and tetL cells were sensitive to tetracycline.     

The urea requirement and urease production of some human species of T-mycoplasmas.

Seven species of human T-mycoplasmas that grow in Fraction A and 20 mug urea/ml died when the urea was omitted. Two species would not grow in Fraction A broth containing 10 mug/urea/ml. The other five strains grew in broth containing 10 mug urea/ml and were adapted by serial passage in broth containing decreasing concentrations of urea to grow in broth containing 2.5 mug/ml urea, but not in broth containing 1.25 mug/ml. Therefore the minimal urea requirement is not the same for the growth of all strains of T-mycoplasmas. In exponential phase broth cultures, urease was detected only intracellularly, none being found in the medium.     

Myelin basic protein-enhanced fusion of membranes

Myelin basic protein caused rapid aggregation of vesicles containing acidic phospholipids. Aggregation could be reversed by trypsin digestion of the myelin basic protein. Aggregated vesicles containing gel phase phospholipids or vesicles containing greater than 15 mol% lysolecithin underwent fusion. The extent of fusion was measured by irreversible changes in the light-scattering intensities or diffusion coefficients of the vesicles. Fusion was also measured by the fluorescence quenching which occurred when vesicles containing a covalently bound fluorophore. N-4-nitrobenzo-2-oxa-1,3-diazole, were fused with vesicles containing the covalently bound spin label, 4,4-dimethyl-oxazolidine-N-oxyl. The kinetics of fusion were first order in phospholipid and had half-times of 0.5-5 min depending on lysolecithin composition. This protein-enhanced membrane fusion may provide a valuable model system for studying some types of biological membrane fusions.     

phbB,phbC Gene Expression in E. coli and Their Transformation and Identification in Potato

Using NADPH-dependent acetoacetyl-CoA reductase gene (phbB) and poly-β-hydroxybutyrate (PHB) synthase gene (phbC) cloned from Alcaligenes eutrophus H16 and expression vector pKK223-3, the authors constructed an E. coli expression vector pKCB containing independent phbB and phbC operators, respectively, and transfered it into E. coli JM109. The microscopy and GC analysis indicated that E. coli JM109 (containing pKCB) induced by IPTG could synthesize poly-β- hydroxybutyrate (PHB). By DNA processing, three tuber-specific plant expression vectors, pP- SAGB (containing phbB), pBIBGC ( containing phbC) and pPSAGCB ( containing both phbB and phbC), were successfully constructed. In 5 transformed potato cuhivars, the authors screened 20 positive lines.