红螯螯虾胚胎发育期主要消化酶和同工酶的活性变化

采用生物化学方法测定了红螯螯虾(Cherax quadricarinatus)胚胎发育各期主要消化酶(胃蛋白酶、胰蛋白酶、淀粉酶、纤维素酶和脂肪酶)的比活力及主要同工酶(乳酸脱氢酶、苹果酸脱氢酶、葡萄糖-6-磷酸脱氢酶和酯酶)的活力。结果显示,5种消化酶各自表现出不同的变化模式,胃蛋白酶和胰蛋白酶的比活力早期均逐渐上升,到发育后期胃蛋白酶出现快速下降,而胰蛋白酶却仍保持较高水平;淀粉酶比活力呈“V”字型变化趋势,晚期活性较高;纤维素酶和脂肪酶的比活力则均较低。4种同工酶酶谱随胚胎的发育渐趋复杂,酶活性也随之增强。结果表明,消化酶和同工酶活力的高低均受其基因的调控,并随胚胎发育适时表达,为胚胎组织、器官和系统的形成以及未来仔虾的开口摄食提供物质保证。     

Lipid signaling

Various lipids are involved in mediating plant growth, development and responses to biotic and abiotic cues, and their production is regulated by lipid-signaling enzymes. Lipid-hydrolyzing enzymes play a pivotal role both in the production of lipid messengers and in other processes, such as cytoskeletal rearrangement, membrane trafficking, and degradation. Studies on the downstream targets and modes of action of lipid signals in plants are still in their early stages but distinguishing features of plant lipid-based signaling are being recognized. Phospholipase D enzymes and phosphatidic acid may play a broader role in lipid signaling in plants than in other systems.     

Studies on enzymes in the developing sea urchin egg

The relative activity of a number of different enzymes has been determined in different developmental stages of normal and Li treated sea urchin eggs.Some enzymes show a constant activity throughout development, whereas the activity of other enzymes is constant up to mesenchymeblastula stage and then increases. A short review of enzymatic changes in other embryonic material is presented. This demonstrated a striking agreement with the sea urchin egg in essential points.It has been suggested that the enzymes which rise in activity at mesenchymeblastula stage are localized in mitochondria, whereas enzymes with constant activity are non-mitochondrial.Li treatment during cleavage stages, which causes vegetalization, inhibits the rise in activity of apyrase, cathepsin II, glutaminase, and according to preliminary experiments also of succinodehydrogenase.The authors conclude that Li treatment during cleavage stages interferes with the later development of mitochondria, possibly by inhibiting the development of their precursors.According to these results, the ectodermal development is characterized by a more important mitochondrial activity, i.e. a more elaborate mechanism of synthesis, than the mesentodermal development. This is at least the case during earlier stages of development.     

Role of the hypothalamus and pituitary gland in the development of pancreatic islet sensitivity to glucose in fetal rats

Differences in the pattern of the development of three enzymes of the plasma membrane have been established. The activity of Na, K-ATPase progressively increases, that of adenylate cyclase decreases, whereas the activity of 5-nucleotidase undergoes only slight changes during embryogenesis. Differences between these enzymes were also found with respect to the development of their sensitivity to the regulatory effects of catecholamines. Adrenaline reactivity of adenylate cyclase may be detected already in embryogenesis; it is lower than that in definite muscle tissue increasing during further ontogenesis. Catecholamine reactivity was not found in Na, K-ATPase and 5-nucleotidase up to the 17th day of incubation of chick embryos. The effect of adrenalin was observed at later stages of ontogenesis, it may be initiated by exogeneous cAMP and protein kinase. At postembryonic stages, similarity in the behavior of these enzymes was found with respect to the presence and pattern of their reaction to adrenalin (stimulation), as well as with respect to temporal dynamics of the effect. The data obtained indicate the existence of close connections between these enzymes, which are realized in the sequence adrenoreceptor-adenylate cyclase-cAMP-protein kinase-effector proteins.     

Changes in Activity of Mitochondrial Enzymes during the Development of Xenopus laevis

Changes in activity of mitochondrial enzymes were studied during the embryonic development of Xenopus laevis.
The following enzymes were determined: malate dehydrogenase (MDH), isocitrate dehydrogenase (NAD⁺-dependent) (IDH), aspartate aminotransferase (GOT), cytochrome oxidase (COX), succinate dehydrogenase (SDH), rotenone-insensitive NADH cytochrome c reductase (NADH-red) and monoamine oxidase (MAO). IDH is constant throughout the period studied. COX and SDH, two enzymes of the inner membrane, are constant in pregastrula stages, and subsequently decrease significantly. MDH and NADH-red are highly active in the pregastrula stages and decline thereafter, while MAO is undetectable during early development and increases significantly only in the larvae. GOT increases during the cleavage stages, being most active in the gastrula stages, and decreases subsequently.
The results are discussed in the sense of mitochondrial differentiation during the early development of the amphibian embryo.     

No association between <Emphasis Type="Italic">NOS2</Emphasis> and <Emphasis Type="Italic">NOS3</Emphasis> polymorphisms and diabetic nephropathy in type 2 diabetics

Background  

Diabetic animal models suggest the involvement of nitric oxide (NO)-producing enzymes in the development of diabetic nephropathy (DN). While early stages of DN are associated with increased intrarenal NO, advanced DN is related to progressive NO deficiency. NO collaborates in reactive nitrogen compounds production, contributing to accelerated oxidative stress. To investigate the impact of genetic polymorphisms of NO-producing enzymes on DN development, we tested 3 polymorphic variants that could affect their function and compared genotype status to an oxidative stress marker.     

Role of enzymes and identification of stage-specific proteins in developing somatic embryos of chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.)

Accumulation of proline, activities of peroxidase (POX), catalase (CAT), phenylalanine ammonia lyase (PAL) and malate dehydrogenase (MDH) were studied during different developmental stages of somatic embryos in chickpea. Callus cultures that did not form somatic embryos served as control. While increased levels of proline and POX activity were noticed in globular stages of embryos, CAT activity increased during early and late heart-shaped embryo formation indicating tissue-specific activation of these enzymes. The activity of PAL reached a peak during torpedo and cotyledonary stages of embryo development. On the other hand, MDH activity enhanced during the germination of somatic embryos inferring more requirement of energy during this stage. Electrophoretic (sodium dodecyl sulfate polyacrylamide gel electrophoresis) pattern of proteins revealed that ten bands are associated with non-embryogenic tissues, whereas 11 bands with globular, heart, torpedo and cotyledonary stages of embryo development and nine bands during the germination stage of embryos. Two extra stage-specific protein bands with molecular masses of 16 and 18 kDa appeared during globular, heart, torpedo, and cotyledonary stages. But, these bands disappeared during germination of embryos and are absent in non-embryogenic cultures. This study thus may help in the identification of proteins and the role of above enzymes during different developmental stages of somatic embryo induction and their maturation in a recalcitrant leguminous crop plant chickpea.     

Molting, enzymes and new targets for chemotherapy of Onchocerca volvulus

Parasitic nematodes do not multiply in definitive hosts, but they do molt, grow and mature for a certain period after infection, after which they devote their energies almost entirely to egg production. In this review, Sara Lustigman describes key metabolic enzymes that are essential to the development of the larval stages of Onchocerca volvulus in the host, making them potential therapeutic targets.     

Proteomic changes associated with the development of açaí (Euterpe oleracea Mart.) seeds

Açaí palm (Euterpe oleracea Mart.) seeds are a rich source of mannans, which can be used to generate bioethanol or be converted to high-value D-mannose, in addition to being a source of polyphenols with beneficial health properties. Here, we present a quantitative proteome dataset of açaí seeds at four stages of development (S1, S2, S3, and S4 stages), in which 2465 high confidence proteins were identified and 524 of them show statistically different abundance profiles during development. Several enzymes involved in the biosynthesis of nucleotide-sugars were quantified, especially those dedicated to the formation of GDP-mannose, which showed an increase in abundance between stages S1 and S3. Our data suggest that linear mannans found abundantly in endosperm cell walls are initially deposited as galactomannans, and during development lose the galactosyl groups. Two isoforms of alpha-galactosidase enzymes showed significantly increased abundances in the S3 and S4 stages. Additionally, we quantified the enzymes participating in the central pathway of flavonoid biosynthesis responsible for the formation of catechin and epicatechin, which are subunits of procyanidins, the main class of polyphenols in the açaí seeds. These proteins showed the same pattern of deposition, in which higher abundances were seen in the S1 and S2 stages.     

Architectonics of the central nervous system of Acoela,Platyhelminthes, and Rotifera

Based on the literature and own data, consecutive stages of development of the central nervous system (CNS) in the lower Bilateria are considered-separation of brain from parenchyma, formation of its own envelopes, and development of the trunk and orthogonal nervous system. Results of histochemical (cholinergic and catecholaminergic) and immunocytochemical (5-HT-and FMRF-amid immunoreactive) studies of the CNS in representatives of Acoela, free living and parasitizing Platyhelminthes and Rotifera are considered. The comparative analysis makes it possible to describe development and complication of the initially primitive Bilateria pleux nervous system. A special attention will be paid to the Acoela phylogenesis, based on molecular-biology data and results of study of their nervous system.     

Development of nerves plexuses in the pelvis of the prenatal rabbit

By means of neurohistological and histochemical methods using serial sections of the embryos at the age of 12-30 days of development, the premediatory and beginning of the mediatory stages in development of cholinergic and adrenergic neural plexuses have been studied in rabbit small pelvis. Appearance of catecholamine-containing cells at early mediatory stages and a gradual development and complication of the cholinergic and adrenergic neural plexuses structure are demonstrated. By birth in the rabbit small pelvis area, some elements of cholinergic and adrenergic structures begin to form.     

Immunolocalization of an alternative respiratory chain in Antonospora (Paranosema) locustae spores: mitosomes retain their role in microsporidial energy metabolism

Microsporidia are a group of fungus-related intracellular parasites with severely reduced metabolic machinery. They lack canonical mitochondria, a Krebs cycle, and a respiratory chain but possess genes encoding glycolysis enzymes, a glycerol phosphate shuttle, and ATP/ADP carriers to import host ATP. The recent finding of alternative oxidase genes in two clades suggests that microsporidial mitosomes may retain an alternative respiratory pathway. We expressed the fragments of mitochondrial chaperone Hsp70 (mitHsp70), mitochondrial glycerol-3-phosphate dehydrogenase (mitG3PDH), and alternative oxidase (AOX) from the microsporidium Antonospora (Paranosema) locustae in Escherichia coli. Immunoblotting with antibodies against recombinant polypeptides demonstrated specific accumulation of both metabolic enzymes in A. locustae spores. At the same time comparable amounts of mitochondrial Hsp70 were found in spores and in stages of intracellular development as well. Immunoelectron microscopy of ultrathin cryosections of spores confirmed mitosomal localization of the studied proteins. Small amounts of enzymes of an alternative respiratory chain in merogonial and early sporogonial stages, alongside their accumulation in mature spores, suggest conspicuous changes in components and functions of mitosomes during the life cycle of microsporidia and the important role of these organelles in parasite energy metabolism, at least at the final stages of sporogenesis.     

DEVELOPMENTAL STUDIES ON GLYOXYSOMES IN RICINUS ENDOSPERM

The development of glyoxysomes and their associated enzymes, isocitrate lyase and malate synthetase, was studied in the endosperm of castor bean seeds during germination and early growth in darkness. The protein content of the glyoxysome fraction, separated by sucrose density centrifugation, increased linearly from day 2 to day 4 and declined subsequently, while maximum enzyme activities were reached at day 5. The specific activities of the enzymes in the glyoxysomes increased until day 5 and remained constant thereafter. At all stages of germination the only organelle with isocitrate lyase activity was the glyoxysome, but at the earlier stages a greater portion of the total activity was recovered in the soluble form. Malate synthetase was found primarily in the glyoxysomes after day 4, but at earlier stages part of the activity appeared at regions of lower density on the sucrose gradient. It was shown that this particulate malate synthetase activity was due to glyoxysomes broken during preparation, and that, as a result of this breakage, isocitrate lyase was solubilized. We conclude that both enzymes are housed in the glyoxysome in vivo throughout the germination period, and that the rise and fall in enzyme activities in phase with fat breakdown correspond to the net production and destruction of this organelle.     

Computer-based substrate specificity prediction for cytochrome P450

Cytochrome P450 is an important class of enzymes metabolizing numerous drugs. The composition and activity of these enzymes determine distribution of drug in the body, their pharmacological and toxic effects. Thus, prediction of the fate of compounds in the body is required at early stages of the development of new drugs. Different isoforms of cytochrome P450 can oxidize a wide range of chemical compounds and their substrate specificity does not correlate with their taxonomical classification. In this review we consider the main methods of cytochrome P450 substrate specificity prediction. These methods are subdivided by primary information used in the analysis: amino acid sequence based prediction, ligand-based (pharmacophore and QSAR models, expert systems) and structure-based (molecular docking, affinity prediction, interaction energy estimation) methods. The common problems complicating cytochrome P450 substrate prediction and advantages and disadvantages of these methods are discussed.     

Peroxidase activity in hooded and awned barley at successive stages of development

The hooded (KK) and awned (kk) genotypes of barley differ in the amount of peroxidase activity at various stages of development. In hooded, this activity is at most stages higher than in awned, but it varies more from one stage to another, so that at certain stages, particularly the first leaf stages of young plants, it is lower. The peroxidase enzymes of the two genotypes are alike in electrophoretic mobility. Since peroxidase activity is particularly high in meristems of hooded at the beginning of their transition from the vegetative to the flowering condition, which is shortly before the first effects on morphogenesis can be observed, a connection between high peroxidase activity and the morphogenetic effects appears likely.     

Architectonics of the central nervous system in Acoela, Plathelminthes, and Rotifera

Based on the literature and own data, consecutive stages of development of the central nervous system (CNS) in the lower Bilateria are considered - separation of brain from parenchyma, formation of its own envelopes, and development of the stem and orthogonal nervous system. Results of histochemical (cholinergic and catecholaminergic) and immunocytochemical (5-HT- and FMRFamid immunoreactive) studies of the CNS in representatives of Acoela, free living and parasitizing Plathelminthes and Rotifera are considered. The comparative analysis makes it possible to describe development and complication of the initially primitive Bilateria plexus nervous system. A special attention will be paid to the Acoela phylogenesis, based on molecular-biology data and results of study of their nervous system.     

Systemic use of “limping” enzymes in plant cell walls

Diversity of proteins and enzymes engaged in carbohydrate metabolism is vast. This is related to the fact that plants contain the greater part of biospheric carbohydrates, whose structures are extremely diverse as well. In plant genomes, proteins involved in carbohydrate metabolism are grouped into numerous families, and each of them may include tens of sequences. This is especially typical of enzymes modifying polysaccharides of the cell wall. Expression of genes encoding such proteins is finely tuned. It may differ in different tissues and organs and depends on stages of development of the entire plant and its particular cells. However, certain genes, including highly expressive ones, encode enzymes with “limping” catalytic centers, which may be unable to conduct reactions characteristic of the particular enzymatic family. The review surveys examples of such proteins and discusses causes of their origin and possible functions.