Structural-functional characteristics of a new bioregulator isolated from bovine pigmented epithelium tissue

A new bioregulator operating in ultralow doses corresponding to 10^?17 mg/ml has been isolated from tissue of pigmented epithelium of bovine eyes. It has been established that the functional basis of this bioregulator is a complex of a low molecular weight regulatory peptide (4372 Da) and a modulator consisting of a mixture of proteins with molecular weights of 14.980–66.283 kDa. It has been shown that the regulatory peptide is responsible for membranotropic activity of the bioregulator, and the modulator proteins are responsible for biological action in ultralow doses. The data demonstrate an interrelation between nanocondition of the bioregulator and its ability to show activity in ultralow doses.     

Identification of a new bioregulator acting in ultralow doses in bulb onion (<Emphasis Type="Italic">Allium cepa</Emphasis> L.)

A bioregulator that has physicochemical and biological properties similar to a group of bioregulators isolated from various animal tissues has been found in the bulb onion (Allium cepa L.). It was determined that the biological action of the plant bioregulator is determined by a peptide with molecular weight of 4036 ± 2 Da whose 18-C-terminal amino acid sequence consisted of 18 residues. On models of seed germination of some vegetable cultures, the ability of the bioregulator isolated from supernatant of onion extract in ultralow doses (10⁻¹³ mg of protein/ml) to inhibit growth and development was demonstrated.     

Studies on the structure of the bioregulator purified from the rat brain

From the brain tissue of Wistar rats, we purified a bioregulator, which is active at ultralow doses. Using reversed-phase HPLC, we prepared a homogenous polypeptide with a molecular weight of 4749 ± 2 Da, which is responsible for the biological activity of the bioregulator. Using the CD spectroscopy method, we calculated the percentage of canonical elements of the secondary polypeptide structure in a solution. Using the methods of proteomics, we revealed that the structure of the investigated polypeptide was similar to the N-terminal sequence of a fragment of guanine-nucleotide binding G₀-protein subunit α-1.     

Identification of a new bioregulator acting in ultralow doses in bulb onion (Allium cepa L.)

A bioregulator that has physicochemical and biological properties similar to a group of bioregulators isolated from various animal tissues has been found in the bulb onion (Allium cepa L.). It was determined that the biological action of the plant bioregulator is determined by a peptide with molecular weight of 4036 +/- 2 Da whose 18-C-terminal amino acid sequence consisted of 18 residues. On models of seed germination of some vegetable cultures, the ability of the bioregulator isolated from supernatant of onion extract in ultralow doses (10(-13) mg of protein/ml) to inhibit growth and development was demonstrated.     

The uptake,transport and metabolism of the bioregulator 2-(3,4-dichlorophenoxy) ethyldimethylamine in guayule

The bioregulator 2-(3,4-dichlorophenoxy) ethyldimethylamine was applied to five-month-old summer and winter guayule plants. Uptake of this molecule depended on the presence of viable trichomes and a well-developed cuticle, in the leaves. Winter plants absorbed the bioregulator more successfully than summer plants. The stem proved to be an active absorption site in young plants. Six days after bioregulator application, transport of the molecule was restricted to the lower stem in summer plants, and stem and leaves in winter plants. Transport was governed by the availability and development of conduits. The intact molecule was recovered two days after application but was not detectable after 4 and 6 days indicating that it is metabolized fairly rapidly. The significance of these findings is discussed in terms of the use of bioregulators to stimulate rubber production in guayule plants.     

Metabolic changes in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) plants under action of bioregulator stifun

Under action of growth-stimulating concentrations of bioregulator stifun on wheat plants, an increase of functional activity of nucleoli of meristematic cells; contents of lectin (wheat germ agglutinin); and activity of proteinases, tripsin inhibitors, and ATPase activity was established. The pool of free amino acids was increased under bioregulator use. Levels of methionine, phenylalanine, cysteine, lysine, leucine and tyrosine were increased. It is likely that stifun could activate protein biosynthesis in wheat plants.     

Metabolic changes in wheat (Triticum aestivum L.) plants under action of bioregulator stifun

Under action of growth-stimulating concentrations of bioregulator stifun on wheat plants, an increase of functional activity of nucleoli of meristematic cells; contents of lectin (wheat germ agglutinin); and activity of proteinases, tripsin inhibitors, and ATPase activity was established. The pool of free amino acids was increased under bioregulator use. Levels of methionine, phenylalanine, cysteine, lysine, and tyrosine were increased. It is likely that stifun could activate protein biosynthesis in wheat plants.     

Decreased lipolysis in peanuts by a pyridazinone bioregulator

Peanut,Arachis hypogaea, plants were treated in the field with the bioregulator BAS 105 00W, 4-chloro-5-dimethylamino-2-phenylpyridazin-3-one, a substituted pyridazinone, at different times of development. The seeds were harvested, dried, hand-shelled, and analyzed for lipoxygenase activity and conjugated diene hydroperoxide content. Reduced lipoxygenase activity occurred when the bioregulator was applied to the plants at flowering and pegging. The conjugated diene hydroperoxide content decreased the most in peanuts when the bioregulator was applied at pegging. The apparent K_m for lipoxygenase of treated peanuts with linoleic acid as substrate was the same as that for untreated peanuts.     

Decreased lipolysis in peanuts by a pyridazinone bioregulator

Peanut,Arachis hypogaea, plants were treated in the field with the bioregulator BAS 105 00W, 4-chloro-5-dimethylamino-2-phenylpyridazin-3-one, a substituted pyridazinone, at different times of development. The seeds were harvested, dried, hand-shelled, and analyzed for lipoxygenase activity and conjugated diene hydroperoxide content. Reduced lipoxygenase activity occurred when the bioregulator was applied to the plants at flowering and pegging. The conjugated diene hydroperoxide content decreased the most in peanuts when the bioregulator was applied at pegging. The apparent K_m for lipoxygenase of treated peanuts with linoleic acid as substrate was the same as that for untreated peanuts.     

A bioregulator of lipid nature--a platelet activating factor (PAF)

The review concerns metabolism, immunological and antihypertensive action of platelet activating factor (PAF), a bioregulator of lipid nature. Major synthetic approaches to PAF and its analogues are described. The effects of structural modification on the physiological activity of PAF are considered.     

Comparison of conformation characteristics of bradykinin and igercin molecules

A certain resemblance of three-dimensional molecular organizations of the known peptide bioregulator bradykinin (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) and the tentative cytophilic centre of the human IgE igercin (Arg-Ala-Val-Ser-Val-Asn-Pro-Gly-Lys) existing along with their pronounced structural similarity was shown by means of energy calculations. This is, however, not the case with the "biologically active" bradykinin conformations suggested earlier.     

Changes of polyamines and ethylene in cucumber seedlings in response to chilling stress

Cucumber ( Cucumis sativus L. cv. Victory) seedlings were exposed to chilling at 5°C and endogenous levels of polyamines and 1-aminocyclopropane-1-carboxylic acid (ACC) were measured after chilling and after warming at 20°C. The level of spermidine was higher in the chilled seedlings than in the non-chilled seedlings. Treatment with a plant bioregulator, (2RS,3RS)-1-(4-cholorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol (paclobutrazol), reduced the chilling injury and the levels of spermidine in the chilled seedlings. The levels of ACC and production of ethylene showed sharp increases after warming following exposure to chilling. These increases were suppressed by the application of aminooxyacetic acid (AOA). However, AOA treatment did not reduce chilling injury or affect the levels of polyamines in the tissue. These data indicate that the increase in ACC and ethylene is a response of the tissue to the chilling exposure and is not a cause of the injury. The data also suggest that the syntheses of polyamines and ethylene are not competitive with each other even under chilling stress conditions.     

Comparative potency of different plant growth retardants in cell cultures and intact plants

A comparison of the efficiency of a broad range of plant growth retardants on cell division growth of 13 cell suspension cultures is presented. The results show that (1) the new plant bioregulator tetcyclacis (NDA) is the compound with the highest activity in inhibiting cell division of all cultures tested, and (2) cell cultures react species-specifically to various compounds. Significant correlations between the results from suspension cultures and intact seedlings of the same plant species demonstrate the usefulness of cell cultures for identifying substances with a growth-regulating potency. Futhermore, the usefulness of cell cultures for establishing structure-activity relationships was shown with structural analogues of chlormequat and mepiquat chloride.     

Scaled-up proliferation and regeneration of Nerine in liquid cultures Part I. The induction and maintenance of proliferating meristematic clusters by paclobutrazol in bioreactors

The natural propagation rate of bulb forming Amaryllidaceae including Nerine is low. Conventional micropropagation techniques are labor intensive and therefore expensive. Liquid cultures facilitate: scaling up, automation and cost reduction of micropropagation. Inflorescence-derived explants of Nerine were cultured on 2,4-dichlorophenoxyacetic acid (2,4-d) and 6-benzyladenine (BA) supplemented Murashige & Skoog (MS) medium. Callus-like tissue interspersed with nodular tissue, as well as direct organogenesis developed at the junction between flower pedicel and peduncle. Subculture of nodular tissue to 1-naphthalene acetic acid (NAA), BA and paclobutrazol (PAC) supplemented liquid medium in Erlenmeyer flasks or bubble bioreactors resulted in proliferation of rounded, compact, easily crumbled meristematic clusters. Growth and proliferation in bioreactors were higher than in shaken flasks and were affected differently by the inoculum to medium ratio in the two types of culture vessel. Nerine cultures showed low sensitivity to high aeration rates in bubble bioreactors despite the accumulation of debris. It was therefore possible to increase aeration rates without reducing the proliferation rate or damaging the quality of the meristematic aggregates. The conditions in semi-continuous culture in flasks and bioreactors were more favorable and increased the growth value by 100% and 140%, respectively. The total protein content increased by 180% in flasks and 90% in bioreactors. Although the presence of PAC throughout the culture period decreased growth and proliferation, it was a promotive bioregulator for meristernatic cluster formation. Proembryogenic clusters developed upon the removal of PAC. The use of meristematic clusters for micropropagation in scaled-up liquid cultures is discussed.     

Comparative potency of different plant growth retardants in cell cultures and intact plants

A comparison of the efficiency of a broad range of plant growth retardants on cell division growth of 13 cell suspension cultures is presented. The results show that (1) the new plant bioregulator tetcyclacis (NDA) is the compound with the highest activity in inhibiting cell division of all cultures tested, and (2) cell cultures react species-specifically to various compounds. Significant correlations between the results from suspension cultures and intact seedlings of the same plant species demonstrate the usefulness of cell cultures for identifying substances with a growth-regulating potency. Futhermore, the usefulness of cell cultures for establishing structure-activity relationships was shown with structural analogues of chlormequat and mepiquat chloride.     

Mitochondria recycle nitrite back to the bioregulator nitric monoxide

Nitric monoxide (NO) exerts a great variety of physiological functions. L-Arginine supplies amino groups which are transformed to NO in various NO-synthase-active isoenzyme complexes. NO-synthesis is stimulated under various conditions increasing the tissue of stable NO-metabolites. The major oxidation product found is nitrite. Elevated nitrite levels were reported to exist in a variety of diseases including HIV, reperfusion injury and hypovolemic shock. Denitrifying bacteria such as Paracoccus denitrificans have a membrane bound set of cytochromes (cyt cd1, cyt bc) which were shown to be involved in nitrite reduction activities. Mammalian mitochondria have similar cytochromes which form part of the respiratory chain. Like in bacteria quinols are used as reductants of these types of cytochromes. The observation of one-e- divergence from this redox-couple to external dioxygen made us to study whether this site of the respiratory chain may also recycle nitrite back to its bioactive form NO. Thus, the aim of the present study was therefore to confirm the existence of a reductive pathway which reestablishes the existence of the bioregulator NO from its main metabolite NO2-. Our results show that respiring mitochondria readily reduce added nitrite to NO which was made visible by nitrosylation of deoxyhemoglobin. The adduct gives characteristic triplet-ESR-signals. Using inhibitors of the respiratory chain for chemical sequestration of respiratory segments we were able to identify the site where nitrite is reduced. The results confirm the ubiquinone/cyt be1 couple as the reductant site where nitrite is recycled. The high affinity of NO to the heme-iron of cytochrome oxidase will result in an impairment of mitochondrial energy-production. "Nitrite tolerance" of angina pectoris patients using NO-donors may be explained in that way.     

The place of carnosine among physiologically active peptides]

The results of analysis of EROP-Moscow data base concerning structural and functional peculiarities of endogenous regulatory oligopeptides are reviewed in relation to carnosine, the first endogenous peptide bioregulator. The dipeptide fragment ala-his is widely distributed in natural systems, in particular in various representatives of living organisms. The main structural peculiarity of carnosine is its elongated "filamentous" structure with a positively charged N-terminus and a cyclic radical characteristic of large physiologically active oligopeptides. The relatedness of carnosine to other oligopeptides also becomes apparent during the analysis of its role in various regulatory systems of the body.     

Post-HMG CoA reductase regulation of cholesterol biosynthesis in normal human lymphocytes: Lanosten-3β-ol-32-al,a natural inhibitor

Normal human lymphocytes stimulated by culture in a lipid-depleted medium were used to study the post-HMG CoA regulations of cholesterol biosynthesis. A thorough analysis of the non-saponifiable material obtained after incorporation of [¹⁴C]-mevalonic acid permitted localization of the main regulatory steps at mevalonic acid degradation (according to the Edmond and Popjak' shunt pathway) and lanosterol demethylation.The last process was blocked essentially at the deformylation of lanosten-3β-ol-32-al, an intermediate which accumulates in the cell. This intermediate which was isolated and identified, has inhibitory properties towards HMG CoA reductase and thus could be considered as an endogenous cellular bioregulator of cholesterol biosynthesis.     

Characterization of Growth-Retardant Effects on Vegetative Growth of Date Palm Seedlings

The leaves, inflorescences, and fruit bunches of date palm trees develop at the crown, which is the apex of a single trunk that can be up to 25 m tall. Because palm trees are monocots, the leaves and inflorescences are generated deep within the trunk from a single meristem—the palm heart—and are inaccessible for direct bioregulator treatments. We followed the effects of two growth regulators, paclobutrazol and uniconazole-P, on the vegetative growth of young date palm seedlings. Both growth regulators constrained the elongation rate of the leaves and reduced the leaf length. Microscopic analysis of dissected palm hearts revealed that the growth retardants did not affect the generation of new leaves. However, the treatments did change the dimensions of the developing embryonic leaves as well as the shape of the apical meristem. The results suggest the possible future use of growth retardants to reduce trunk height, enabling cheaper, safer, and more efficient management of date palm trees.