Cytoplasmic Male Sterility in Barley : VIII. LIPOXYGENASE ACTIVITY AND ANTHER AMINO NITROGEN IN THE msm1-Rfm1a SYSTEM

The lipoxygenase (LOX) activity was determined in almost isogenic types of barley (Hordeum vulgare L.): normal cv. Adorra, cytoplasmic male sterile (msm1), and msm1 barley with restored fertility, heterozygous for the Rfm1a restorer gene. The LOX activity was lowest in male steriles in the leaf tissue studied at the anthesis stage. The LOX activity in developing anthers was higher than in leaf tissue, and decreased during degeneration of the sterile anthers.     

Changes in lipoxygenase activity in relation to lipid degradation in plucked tea shoots

The activity of lipoxygenase in tea leaf increased after plucking of tea shoots. The changes of lipoxygenase activity were accelerated by the dehydration of tea leaves. The activity of lipoxygenase was higher in the good fermenting clones than in the poor fermenting clones of black tea. The content of peroxide in tea shoots increased with rising lipoxygenase activity.     

Activity of soybean lipoxygenase isoforms against esterified fatty acids indicates functional specificity

In soybean (Glycine max L.) vegetative tissue at least five lipoxygenase isozymes are present. Four of these proteins have been localized to the paraveinal mesophyll, a layer of cells that is thought to function in assimilate partitioning. In order to determine the role of the lipoxygenase isozymes within the soybean plant, the leaf lipoxygenases were cloned into bacterial expression vectors and expressed in Escherichia coil. The recombinant lipoxygenases were then characterized as to substrate preference, pH profiles for the most common plant lipoxygenase substrates, linoleic acid, and alpha-linolenic acid, and the reaction products with the substrates linoleic acid, alpha-linolenic acid, arachidonic acid, gamma-linolenic acid, and the triacylglycerol trilinolein. All five enzymes were shown to be (13S)-lipoxygenases against linoleic acid. The results of these assays also indicate that two of these isozymes are highly active against esterified fatty acid groups, such as those found in triacylglycerols. Lipid analysis of leaves from plants subjected to sink limitation conditions indicates that the soybean leaf lipoxygenases are active in vivo against both free fatty acids and esterified lipids, and that the quantities of lipoxygenase products found in leaf tissue show a positive correlation with the level of lipoxygenase in the leaf. Implications for the putative role of these enzymes in the paraveinal mesophyll are discussed.     

Cell type specific expression of a CaMV 35S-GUS gene in transgenic soybean plants

A number of independently derived transgenic soybean plants expressing a chimeric β-glucuronidase (GUS) gene under the control of the 355 CaMV promoter and a nopaline synthase polyadenylation signal were recovered using direct DNA transfer via electric discharge particle acceleration. Expression of GUS in R, plants was localized using thin tissue sections. Many tissue types expressed GUS at various levels. Pericycle cells in root, parenchyma cells in xylem, and phloem tissues of stem and leaf had high levels of enzyme activity. Procambium, phloem, and cortex cells in root, vascular cambium cells in stem, and the majority of cortex cells in leaf midrib, expressed low or no GUS activity. Intermediate levels of GUS activity were detected in leaf mesophyll cells, certain ground tissue cells in stem and leaf midrib, and in trichome and epidermal guard cells. Thus, we conclude that the 35S CaMV promoter is cell-type specific and is developmentally regulated in soybean.     

Soybean leaves contain multiple lipoxygenases

Chromatofocusing of soybean (Glycine max L.) leaf lipoxygenases revealed three distinct peaks of activity. Based on their isoelectric points (pls), pH optima, and mutant analysis it appears that the leaf isozymes are different from those described from mature soybean seed. At least one leaf lipoxygenase appears to differ from those found in hypocotyls. The pls of the main bands of the three leaf lipoxygenase peaks are 6.67, 5.91, and 5.67. The pH optima curves of three active fractions exhibit peaks at pH 6.2, 5.5, and 8.5, respectively. One of the fractions has two polypeptides with slightly different molecular weights, both of which react to soybean seed lipoxygenase antibodies. The other two fractions contain a polypeptide of unit molecular weight reacting with the lipoxygenase antibodies.     

Lowering of Endogenous Lipoxygenase Activity in Pisum sativum Foliage by Cytokinin as Related to Senescence

Cytokinin (CK), when applied to intact pea plants, considerably lowered endogenous lipoxygenase levels. Furthermore it was demonstrated that the triggering of senescence induced by leaf detachment was invariably accompanied by a significant increase of lipoxygenase activity and the CK application considerably decelerates lipoxygenase increment. It is suggested that the lipoxygenase repression induced by CK is a contributing mechanism to the overall antisenescence action of the hormone, and that this may have biological implications.     

Role of oxidative stress in cereal protoplast recalcitrance

Cereal leaf protoplasts are often extremely unstable in culture and usually lyse within 24 hours. Using the thiobarbituric acid test and the ferrous thiocyanate test we have shown that corn (Zea mays L. cv. Market Beauty) and wheat (Triticum aestivum L. cv. Benito) leaf protoplasts accumulate peroxides and peroxide degradation products during culture. This increase correlated with an increase in lipoxygenase activity. On the other hand, enzymes involved in detoxification of peroxides such as catalase and peroxidase decreased during culture. The occurrence of lipid peroxidation in leaf protoplasts is likely to be a consequence of a temporary imbalance in the enzymes involved in oxygen metabolism. It has previously been shown that the lipoxygenase inhibitor n-propyl gallate stabilizes the protoplasts in culture and so peroxidation is likely to be the cause of leaf protoplast instability. Protoplasts obtained from suspension cultures are stable in culture and do not undergo lipid peroxidation. This stability is due to a decrease in lipoxygenase activity and increases in catalase and peroxidase activity after protoplast isolation.Abbreviations MDA malonaldehyde - 2,4-D 2,4-dichlorophenoxyacetic acid - PVP polyvinylpolypyrrolidone Dedicated to Dr. Friedrich Constabel on the occasion of his 60th birthday     

重组人BMP-2在烟草不同组织中的表达

骨形态发生蛋白（BMPs）是一类调节骨组织发育的生长因子。BMP-2是BMP家族中诱骨活性最强的。在骨组织工程研究和临床应用中需要大量的BMP-2。因此,研究出一种能够有效地大量生产BMP-2的方法是十分必要的。随着植物分子生物学的进展,转基因植物被用作一种生物反应器来生产目的蛋白。以gus作为报告基因,研究了重组人bmp-2基因在烟草中的表达。通过GUS活性检测、半定量PCR和Western blotting分析了根、茎、叶组织中基因表达的水平,结果显示融合蛋白在根和茎组织中表达量显著高于叶组织。由于根和茎组织中蛋白组成与叶组织相比相对简单,提示其更易于进行目的蛋白的纯化。     

Influence of calcium chloride and benzyladenine on lipoxygenase of Vigna unguiculata leaf discs during senescence

Cowpea ( Vigna unguiculata L.) leaf discs incubated in the dark in CaCl₂ and benzyladenine maintained higher levels of chlorophyll and protein than controls. The CaCl₂ or benzyladenine treatments reduced lipoxygenase activity, and the effect of these compounds in combination was additive. HPLC analysis of the product profile of lipoxygenase activity with arachidonic acid as a substrate showed a single peak comigrating with standard 15-hydroperoxyeicosatetraenoic acid. There appears to be a strong temporal correlation between the CaCl₂+ benzyladenine delay of senescence and lipoxygenase activity.     

柑桔砧木矮化特性分类研究

以３１种柑桔砧木为试材,对根皮率,根导管总面积,栅海比,叶片气孔密度,茎还原性糖含量,叶片还原性糖含量,叶片氨基酸含量,茎蛋白质含量,叶片过氧化物酶活性９个柑桔砧木矮化预选指标进行测定,采用聚类分析的方法,将这些砧木分为矮化砧,半矮化砧、半乔化砧、乔化砧４类。     

Expression of Human BMP-2 Gene in Different Tissues of Tobacco Plants

The bone morphogenetic proteins (BMPs) are a family of growth factors that regulate the development of bone. BMP-2 is the most effective in the induction of bone tissue. A large amount of BMP-2 is needed for both bone tissue engineering research and clinical application. Thus, an effective way is necessary to produce sufficient BMP-2 protein. With the advance in plant biotechnology, transgenic plants have been targeted as a bioreactor to produce desired recombinant proteins. Here, the expression of recombinant human bmp-2 gene (rhbmp-2) was studied in tobacco plants using gus as a reporter gene. The difference of expression levels in root, stem and leaf tissues was analyzed by GUS activity assay, semi-quantitive RT-PCR and western blotting. The results indicated that the expression levels of fusion protein in root and stem tissues were significantly higher than those in leaf tissue. For the protein compositions in root and stem tissues were simpler than those in leaf tissue, this suggested that the purification process with root and stem tissues would potentially be easier.     

Lipoxygenase activities of young wheat leaves

Lipoxygenase activity has been measured in various sections of the growing first leaf of wheat ( Triticum aestivum L. cv. Florence Aurore). Weight, chlorophyll and lipoxygenase activity have been determined during the growth of the coleoptile and of the first and second leaf. Lipoxygenase activity variations are correlated with the growth of each organ. It seems that this enzyme has to do with chloroplast growth rather than with chloroplast division.     

Peroxidase Activity in Linum usitatissimum L

Peroxidase activity was measured at three stages, from seedlingto maturity, in leaf and stem tissue of two genotypes of Linumusitatissimum. The plants were grown throughout in growth chambers,allowing close control of the environmental conditions. Therewere large and consistent differences between activities inthe genotypes, between leaf and stem tissue, and between dialyzedand undialyzed extracts. Dialysis appeared to remove inhibitor(s).The consistency of the genotypic differences under these conditionspermitted reliable comparisons, from the seedling stage to maturity,to be made, a finding relevant to inheritance studies of peroxidaseactivity.     

Reactive Oxygen Species Activity and Antioxidant Properties of Fusarium Infected Bananas

Fusarium infection of bananas is a global problem that threatens the production of bananas. This study looks at the effects of the infection upon the reactive oxygen species (ROS) system, as well as the induced antioxidant properties in the roots, stems, leaves and fruits. Results show that there is a greater amount of damage in infected tissue samples as opposed to non‐infected. The damage was observed to be higher in the root samples. ROS assays were divided into two classes: ROS assays and ROS‐scavenging assays. Of the ROS assays, lipoxygenase was observed to be higher in the infected samples, while peroxidase (POD) and polyphenol oxidase (PPO) were significantly higher in infected stem, leaf and fruit samples. Among root samples, there was no significant difference in POD activity and PPO was lower in infected samples. Induction of ROS is important for the hypersensitive response (HR) to function properly. The ROS‐scavenging enzymes, namely ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase, exhibited higher levels in the infected tissue. This is most likely to counter the build‐up of the ROS enzymes and to prevent further cell death. The increase in ROS‐scavenging assays also correlates with higher antioxidant properties as antioxidants play a critical role in regulating the HR free radicals.     

The Vascular Pattern of Italian Ryegrass (Lolium multiflorum Lam.) 4. The Peripheral Plexus, and Nodal Root Insertion

The interconnecting system of leaf traces constitutes only afraction of the vascular tissue found in the base of a ryegrassstem. The tillers and nodal roots have their insertion in thiscongested region of the plant in addition to the majority ofthe leaf traces. Study of the attachment of nodal roots revealsthe extensive differentiation of vascular tissue in a perforatedcylinder surrounding the inner leaf trace system—the peripheralplexus. This plexus consists of two components, the diffuse bundlesorientated along the stem axis, and interconnected with theroot girdles orientated around the stem axis. The peripheralplexus which is bounded externally by a mestome sheath, makesnumerous contacts with the leaf trace system within it, bothdirectly and via the nodal plexi, and receives the vascularattachment of all the nodal roots. It appears in the stem atabout the same time as adjacent nodal roots, and differentiatesfrom meristematic tissue totally independently of the leaf tracesystem. The diffuse bundles themselves apparently differentiateacropetally in this meristematic tissue and are augmented bybranches from leaf traces and the nodal plexi. The integrated vascular systems of leaf, stem, and root at thebase of the grass plant, bounded by a mestome sheath, must allowtotal intercommunication between all organs. Nearly all tissuewithin the mestome sheath is vascular in nature and it is intothis vascular tissue that the leaf traces associated with transfercells are inserted.     

Cytochemical localization of ATPase activity in phloem tissues ofRicinus communis

Summary Standard lead precipitation procedures have been used to examine the localization of ATPase activity in phloem tissues ofRicinus communis. Reaction product was localized on the plasma membrane of the companion cells associated with sieve elements and of parenchyma cells in phloem tissues from the leaf, petiole, stem and root. ATPase activity was also present on the plasma membrane and dispersed P-protein of sieve elements in petiole, stem and root tissue, but was absent from the plasma membrane of these cells in the leaf minor veins. Substitution of-glycerophosphate for ATP produced no change in the localization of reaction product in leaf tissue. These findings are discussed in relation to current theories on the mechanism of sugar transport and phloem loading.     

落葵薯粘液细胞分布及发育的解剖学研究

采用石蜡切片法对落葵薯(Anredera cordifolia(Tenore)Steenis)粘液细胞的分布及发育进行了研究。结果表明,粘液细胞普遍存在于落葵薯的茎、叶、叶柄中,粘液细胞单个散生分布于茎的髓及皮层组织中;叶的栅栏组织和海绵组织中都可见粘液细胞,且海绵组织中的数量明显多于栅栏组织中的;叶柄中的粘液细胞不多,主要分布在维管束四周的皮层组织中。粘液细胞的发育分为4个阶段:原始细胞阶段、液泡化阶段、成熟阶段和细胞质解体阶段。粘液细胞最早出现于第六叶原基,且其发育与茎、叶器官的组织分化不同步。     

A Model of the Partitioning of New Above-ground Dry Matter

A model for the partitioning of new above-ground dry matterof a vegetative dicotyledonous plant is developed. It assumestwo distinct functional components of the stem tissues. One,the primary stem tissue, includes physiologically active tissuessuch as xylem, phloem and meristematic tissues, and the other,secondary stem tissue, includes the main mechanical structures.The model is used to examine the partitioning of dry matterbetween leaf and stem tissues, and its behavour is comparedwith experimental observations. Partitioning, leaf, stem, secondary stem tissues     

Plant leaf and stem proteins. I. Extraction and electrophoretic separation of the basic, water-soluble fraction

Simplified but highly reproducible extraction and electrophoretic procedures have been developed for plant stem and leaf proteins using recent chemical and technical advances. The method is applied to the separation of the basic, water-soluble proteins found in stem and leaf tissues of 3 Dianthus clones. While most of the highly reproducible protein bands appear in all 3 selections, and many are also common to both leaf and stem tissue, others are characteristic for the variety or tissue.     

The Lipoxygenase Isozymes in Soybean [Glycine max (L.) Merr.] Leaves (Changes during Leaf Development,after Wounding,and following Reproductive Sink Removal)

The levels of individual lipoxygenase isozymes in soybean [Glycine max (L.) Merr.] leaves were assessed during leaf development, after mechanical wounding, and in response to reproductive sink removal. Native isoelectric focusing followed by immunoblotting was employed to examine individual lipoxygenase isozymes. In leaves of all ages, two distinct classes of lipoxygenase isozymes were detected. One class of lipoxygenase isozymes had nearly neutral isoelectric points (pls) ranging from pH 6.8 to 7.2. The other class of lipoxygenase isozymes had acidic pls ranging from pH 4.7 to 5.6. During leaf development, all of the neutral lipoxygenase isozymes and most of the acidic isozymes were present in greatest abundance in the youngest leaves examined and declined in amount as leaf age increased. However, four acidic lipoxygenase isozymes (pl = 4.70, 4.80, 4.90, 4.95) were more abundant in intermediateage leaves than in either the youngest or oldest leaves examined. Following mechanical wounding of leaves, these same four acidic isozymes also increased in abundance both locally and systemically in leaves from wounded plants. Unlike the specific effects of wounding on the lipoxygenase isozymes in leaves, reproductive sink removal stimulated a general increase in most of the acidic lipoxygenase isozymes in leaves.