A novel, cellulose synthesis inhibitory action of ancymidol impairs plant cell expansion

The co-ordination of cell wall synthesis with plant cell expansion is an important topic of contemporary plant biology research. In studies of cell wall synthesis pathways, cellulose synthesis inhibitors are broadly used. It is demonstrated here that ancymidol, known as a plant growth retardant primarily affecting gibberellin biosynthesis, is also capable of inhibiting cellulose synthesis. Its ability to inhibit cellulose synthesis is not related to its anti-gibberellin action and possesses some unique features never previously observed when conventional cellulose synthesis inhibitors were used. It is suggested that ancymidol targets the cell wall synthesis pathway at a regulatory step where cell wall synthesis and cell expansion are coupled. The elucidation of the ancymidol target in plant cells could potentially contribute to our understanding of cell wall synthesis and cell expansion control.     

Unsaturated sugars in enantiospecific synthesis of natural low-molecular bioregulators and their structural analogues

The review of works of the authors devoted to the synthesis of low-molecular bioregulators with the use of unsaturated sugars is presented. The schemes of synthesis of insect pheromones and acetogenins and glycophosphingolipids on the basis of glycals are discussed. The pathways of synthesis of triterpene 2-deoxy-α-glycosides are shown. The synthesis of prostanoids from levoglucosenone is considered.     

Patterns of protein synthesis in livers of Xenopus laevis during metamorphosis: Effects of estrogen in normal and thyrostatic animals

Two-dimensional gel electrophoresis has been used to analyse protein synthesis in the livers of Xenopus laevis larvae during metamorphosis. The patterns found at different developmental stages have been characterised and compared to those found in developmentally static tadpoles and estrogen-treated tadpoles. The results suggest that the majority of proteins synthesized by the larval liver during metamorphosis can be divided equally into three main categories: those which are synthesized continuously, those whose synthesis is lost, and those whose synthesis is gained during development. The synthesis of proteins tends to be lost earlier in metamorphosis than it is gained. The pattern of liver protein synthesis in thyrostatic animals is not characteristic of any single stage of normal development, and displays features characteristic of many different stages. About half the changes in protein synthesis which occur during normal metamorphosis are dependent upon it. All the stages examined are responsive to estrogen, and each has a characteristic response. Half of the estrogen-induced changes in protein synthesis are independent of metamorphosis, while the other half require metamorphosis.     

A review on the biosynthesis of metallic nanoparticles (gold and silver) using bio-components of microalgae: Formation mechanism and applications

The synthesis of nanoparticles (NP) using algae has been underexploited and even unexplored. In recent times, there are few reports on the synthesis of NP using algae, which are being used as a bio-factory for the synthesis. Moreover, the algae are a renewable source, so that it could be effectively explored in the green synthesis of NP. Hence, this review reports on the biosynthesis of NP especially gold and silver NP using algae. The most widely reported NP from algae are silver and gold than any other metallic NP, which might be due to their enormous biomedical field applications. The NP synthesized by this method is mainly in spherical shape; the reports are revealing the fact that the cell free extracts are highly exploited for the synthesis than the biomass, which is associated with the problem of recovering the particles. Besides, mechanism involving in the reduction and stabilization is well demonstrated to deepen the knowledge towards enhancement possibilities for the synthesis and applications.     

一种新的等温单向生长基因合成法初步探索

基因合成正日益成为基因获取的一种有效手段。两种常用的基因合成方法是基于PCR的基因合成（P法）和基于连接酶的基因合成(L法)。这两种方法都不是独立于所合成基因的序列内容的。文章首次提出了一种新的基因合成策略—等温单向生长法(Isothermal Unidirectional Elongation Method, IUEM), 在3种酶的作用下, DNA链在等温状态下单向串行延伸, 直到获得目标基因。由于引物设计成特殊的发夹结构, 该方法可以做到合成过程独立于或部分独立于目标基因的序列内容。本文探索了该策略的实验可行性, 检测了影响基因合成的各种因素, 并利用该方法成功地合成了一段254 bp和一段300 bp的DNA序列。     

Synthesis of bioprocesses using physical properties data

The aim of this article is to illustrate and evaluate a synthesis procedure which has been extended to tackle bioprocesses. Physical property information is used to screen candidate units thereby reducing the size of the synthesis problem. In this way, only units which exploit large property differences between components in a stream are selected. This is important for bioprocesses because of the large number of components and wide range of unit operations which are available. The screening technique and bioprocess-unit-design methodologies have been incorporated within an implicit enumeration algorithm which was developed for chemical process synthesis and is implemented in Java programming language. An important advantage is the ability of the bioprocess synthesis software to generate a ranked list of flowsheets which may subsequently be analyzed in more detail. Two case studies are used to evaluate the bioprocess-synthesis technique. The first system involves a product which is secreted from the host organism. The second has significantly different characteristics in that the product is intracellular and forms inclusion bodies. The latter case study, in particular, is a large synthesis problem with 12 unit operations and 20 contaminant compounds. The results show that the synthesis methodology identifies a set of economically optimal flowsheets in a reasonable computational time which demonstrates its ability to deal with large synthesis problems. Using the synthesis methodology we can generate bioprocesses which are optimal in a system-wide, rather than unit-by-unit, sense.     

Replicative Deoxyribonucleic Acid Synthesis in Isolated Mitochondria from Saccharomyces cerevisiae

The characteristics of a system for the in vitro synthesis of mitochondrial deoxyribonucleic acid (mtDNA) in mitochondria isolated from Saccharomyces cerevisiae are described. In this system the exclusive product of the reaction is mtDNA. Under optimal conditions the initial rate of synthesis is close to the calculated in vivo rate; the rate is approximately linear for 20 min but then decreases gradually with time. DNA synthesis proceeds for at least 60 min and the de novo synthesis of an amount of mtDNA equivalent to 15% of the mtDNA initially present is achieved. The rate and extent of synthesis observed with mitochondria isolated from grande and petite (rho(-)) strains were similar. The mode of DNA synthesis is semiconservative; after density labeling with 5-bromodeoxyuridine triphosphate, in vitro, the majority of labeled DNA fragments of duplex molecular weight, 6 x 10(6), are of a density close to that calculated for hybrid yeast mtDNA. The density label is incorporated into one strand of the duplex molecules. These properties indicate that the synthesis resembles replicative rather than repair synthesis. This system therefore provides a convenient method for the study of mtDNA synthesis in S. cerevisiae. The observation that mtDNA synthesis is semiconservative in vitro suggests that the dispersive mode of synthesis observed in S. cerevisiae in vivo labeling studies is the result of some other process, possibly a high recombination rate.     

DNA and protein synthesis in cultured lens epithelial cells. II. Activity of synthetic effectors]

Cultivated bovine lens epithelium cells are highly susceptible to inhibitors of DNA-, RNA- and protein synthesis. The strict correlation between inhibition by puromycin of protein and DNA synthesis suggests that, in the cell system investigated, protein synthesis is essential for DNA synthesis to occur. Studies with actinomycin D have shown that in cultivated lens epithelium cells, part of protein synthesis is accomplished through a relatively long-lived mRNA. In long-term cultivation experiments, no further stabilization of mRNA, which is typical of lens fibre cells, could be demonstrated. There are indications that high doses of actinomycin D produce direct inhibition of DNA synthesis. By means of cytosine arabinoside a linear relationship was established between concentration of the effector and inhibition of DNA synthesis. Protein synthesis remains virtually unaffected even after high doses. The strong inhibition of DNA synthesis with protein synthesis continuing ("unbalanced growth") could not be utilized for the synchronization of lens epithelium cells, because it was only partly reversible after changing the medium and applying deoxycytidine.     

Intermediary metabolism of adipose tissue.

Metabolism of ruminant adipocytes involves the synthesis and mobilization of lipids. Rates of lipid synthesis from the uptake of preformed fatty acids (via lipoprotein lipase) and de novo synthesis of fatty acids are related to the energy balance. Acetate is the major carbon source for fatty acid synthesis with NADPH originating from the pentose cycle and the isocitrate cycle. Ruminant adipose tissue lacks the ability to utilize for lipogenesis those substrates that generate mitochondrial acetyl CoA because of an absence of ATP citrate-lyase and NADP-malate dehydrogenase. Lipid mobilization in ruminant adipocytes is apparently regulated via cAMP levels and a summary of the compounds investigated for lipolytic responses is presented. The control of lipid synthesis and mobilization is interrelated in ruminant adipose tissue. The coordinated manner in which these two functions are regulated is examined with regard to adipocyte responses to insulin and epinephrine. In both lipid synthesis and lipid mobilization, ruminant adipocytes are uniquely different from nonruminant adipose tissue. The physiological significance and possible basis for these species differences in adipose metabolism are discussed.     

A novel effect of 6-azauridine on growth and protein synthesis in wheat embryonic axes

Growth and the rate of protein synthesis in germinating wheat embryonic axes are inhibited by the analog 6-azauridine via a mechanism which is independent of the usual effect of this compound as an inhibitor of de novo synthesis of UTP. The effects on growth and protein synthesis can be separated from that on UTP biosynthesis by analyses of the kinetics by which each effect is maximized following a 1.5-h pulse with 6-azauridine, and by saturation of the responses at different doses of the analog. The inhibitions of growth and protein synthesis are apparently not mediated through the rate of poly A(+) RNA synthesis (reduced as little as 8%), but rather by an effect on translation. Since cordycepin reduces the azauridine inhibitions of growth and protein synthesis, it is suggested that these latter effects of 6-azauridine may depend upon the synthesis of an inhibitory azauridyl-RNA.     

Psoralen plus near-ultraviolet light: a possible new method for measuring DNA repair synthesis

A new method is proposed to inhibit semiconservative DNA synthesis in cultured cells while DNA repair synthesis is being measured. The cells are treated with the DNA-crosslinking agent Trioxalen (4,5,8-trimethylpsoralen) plus near-ultraviolet light, and consequently 99.5% inhibition of replicative DNA synthesis is achieved. Additional DNA-damaging agents induce thymidine incorporation into the double-stranded regions of the DNA. The new method gave results very similar to those obtained with the benzoylated naphthoylated DEAE (BND) cellulose method using three human fibroblast strains, of which one had deficient capacity for DNA repair synthesis following treatment with gamma rays and methyl methanesulfonate. The advantages of the new method are simplicity and rapidity, as well as the high extent to which replicative DNA synthesis is inhibited.     

The regulation of RNA synthesis in yeast IV

Summary A study has been made of the regulation of the synthesis of Pl double-stranded (ds) RNA, the genome of the yeast virus-like particle. When yeast protein synthesis is prevented by starvation for a required amino acid or by addition of cycloheximide, the rate of Pl dsRNA synthesis is reduced markedly. During nitrogen starvation the synthesis of Pl dsRNA persists but is accompanied by the degradation of pre-existing molecules. This degradation appears to require the induction of new enzymes and it is likely that the breakdown products are used to enable the cell to complete its division cycle. However, all of the copies of the VLP genome are not degraded in this process, some are conserved and can replenish the amount of Pl dsRNA on return to growth conditions. The controls which must operate on Pl dsRNA synthesis are discussed and compared with those exerted on nuclear RNA synthesis in yeast.Paper III in this series is Elliott and McLaughlin (Molec. Gen. Genet., In press)     

Histone synthesis is not coupled to the replication of adenovirus DNA

Histone synthesis decreases approximately in parallel with the decrease in cellular DNA synthesis when KB cell monolayers are productively infected with adenovirus type 2 and does not occur in coordination with the later surge of viral DNA synthesis. The synthesis of histones is not, therefore, required for all replicative DNA synthesis in the nuclei of mammalian cells.     

Untersuchungen über die Regulation der DNS-Synthese während des Aktivitätswechsels vonAgrostemma githago-Samen

The relationships between DNA synthesis and germination capacity ofAgrostemma seeds have been studied. Protein synthesis and RNA synthesis are activated at the very beginning of imbibition, whereas DNA synthesis starts in the second part of the imbibition phase. Agrostemma seeds inhibited by higher temperature (30° C), or aged seeds with a low germination capacity are characterized by a remarkably reduced protein synthesis. DNA synthesis is also reduced. The inhibition of protein-synthesis ofAgrostemma embryos fed with cycloheximid or actinomycin D causes a depression of DNA synthesis. These results indicate that the initiation of DNA synthesis of imbibingAgrostemma seeds depends on the synthesis of special proteins. Abscisic acid inhibits growth as well as DNA synthesis of isolatedAgrostemma embryos. Mitomycin inhibits germination and DNA synthesis to the same extent. Dormant seeds with an undiminished intensity of protein synthesis also show a reduced incorporation of³H-thymidine in DNA. We suggest that DNA synthesis of imbibed seeds, which is a necessary prerequisite for the radicle protrusion, is involved in the mechanism of afterripening of theAgrostemma seeds.     

Kinetics of the enzymatic synthesis of benzylpenicillin

The kinetics of the enzymatic synthesis of benzylpenicillin catalysed by penicillin amidase (EC 3.5.1.11) from Escherichia coli have been studied. Both free phenylacetic acid (PAA) and its activated derivative, phenylacetylglycine (PAG), were used in the synthesis as acylating agents for 6-aminopenicillanic acid (6-APA). The catalytic rate constants for synthesis carried out at pH 6.0 were 11.2 and 25.2 s⁻¹, respectively, i.e. they are close and have high absolute values. The main feature of the enzymatic synthesis of benzylpenicillin from phenylacetylglycine, compared with the synthesis from phenylacetic acid, is the shape of the progress curve of antibiotic accumulation. In the former case, benzylpenicillin gradually accumulates until equilibrium is reached. Thus, if the reaction is carried out at the thermodynamically optimum pH of synthesis (low pH), penicillin can be obtained in high yield. In the case of phenylacetylglycine, the kinetic curves are more complex and are characterized by a clear-cut maximum. The presence of the maximum, its value and position on the time axis depend on reagent concentration and on the pH used. A kinetic scheme is proposed which describes well the experimental dependencies. The possibility of using activated acid derivatives in synthesis and the advantages of using computer calculations for process optimization are discussed.     

Seaweeds: A resource for marine bionanotechnology

Marine bionanotechnology is one of the most promising areas of research in modern science and technology. Although there are multitude methods for the synthesis of nanoparticles (NPs), there is an increasing attention in developing high-yield, low-cost, non-toxic and eco-friendly procedures. The vital advantages of greener synthesis are cost-effective, reduced usage of toxic chemicals and abundant availability of resources. During the last ten years, there have been many biological entities used to elevate novel, greener and affordable methods for the metal NPs synthesis. Rate of synthesis and stability are higher for plant material mediated NPs. However, in comparison with terrestrial resources, marine resources have not been fully explored for synthesis of noble metal NPs. Our present review is designed to speculate the importance of usage of vast marine resources and its mediated NPs synthesis, in particular seaweed-mediated NPs synthesis to overcome the limitations involved in physical and chemical methods. Finally, recent advancements in greener synthesis of metal NPs, their size, distribution, morphology and applications such as antimicrobial, antifouling and anticancer potentials are briefly described along with portraying the prospective scope of research in this field without any negative impact on the environment.