scholarly journals Effect of methanol on the frequency of respiration-deficient mutation induced by ethidium bromide in yeast under growing and non-growing conditions.

1988 ◽  
Vol 36 (12) ◽  
pp. 4865-4870 ◽  
Author(s):  
HIROSHI HAMADA ◽  
MIYUKI YAMASHITA ◽  
NOBUHIRO KASHIGE ◽  
MISAO KOJIMA ◽  
TAMOTSU MORITA
Author(s):  
K. S. McCarty ◽  
R. F. Weave ◽  
L. Kemper ◽  
F. S. Vogel

During the prodromal stages of sporulation in the Basidiomycete, Agaricus bisporus, mitochondria accumulate in the basidial cells, zygotes, in the gill tissues prior to entry of these mitochondria, together with two haploid nuclei and cytoplasmic ribosomes, into the exospores. The mitochondria contain prominent loci of DNA [Fig. 1]. A modified Kleinschmidt spread technique1 has been used to evaluate the DNA strands from purified whole mitochondria released by osmotic shock, mitochondrial DNA purified on CsCl gradients [density = 1.698 gms/cc], and DNA purified on ethidium bromide CsCl gradients. The DNA appeared as linear strands up to 25 u in length and circular forms 2.2-5.2 u in circumference. In specimens prepared by osmotic shock, many strands of DNA are apparently attached to membrane fragments [Fig. 2]. When mitochondria were ruptured in hypotonic sucrose and then fixed in glutaraldehyde, the ribosomes were released for electron microscopic examination.


Author(s):  
E. Keyhani

The mutagenic effect of ethidium bromide on the mitochondrial DNA is well established. Using thin section electron microscopy, it was shown that when yeast cells were grown in the presence of ethidium bromide, besides alterations in the mitochondria, the plasma membrane also showed alterations consisting of 75 to 110 nm-deep pits. Furthermore, ethidium bromide induced an increase in the length and number of endoplasmic reticulum and in the number of intracytoplasmic vesicles.Freeze-fracture, by splitting the hydrophobic region of the membrane, allows the visualization of the surface view of the membrane, and consequently, any alteration induced by ethidium bromide on the membrane can be better examined by this method than by the thin section method.Yeast cells, Candida utilis. were grown in the presence of 35 μM ethidium bromide. Cells were harvested and freeze-fractured according to the procedure previously described.


Author(s):  
I.I. Seregina ◽  
◽  
I.G. Makarskaya

Abstract:In model experiments in soil culture, the effect of different methods of treatment with sodium selenite on the photosynthetic activity of spring wheat variety Zlata was studied under extreme growing conditions. Under drought conditions, the inhibition of the growth of the photosynthetic surface of spring wheat plants was revealed. Under conditions of excessive water supply, a sharp decrease in the area of the assimilating surface of wheat plants was observed. The positive effect of sodium selenite solution on the photosynthetic activity of spring wheat plants was established with insufficient and excessive water supply to wheat plants.


2012 ◽  
Vol 11 (9) ◽  
pp. 1721-1724
Author(s):  
Roxana Vatavu ◽  
Constantin Leonte ◽  
Teodor Robu. ◽  
Catalina Slabu-Pascal

Author(s):  
R. V. Kulyan

The Russian Research Institute of Floriculture and Subtropical Crops has the citrus germplasm collection, in total over 150 genotypes of various origins including 30 wild and semi-wild relatives. As a result of controlled hybridization in 17 crossings combinations of with the participation of relatives of citrus plants, new 769 hybrid offspring were obtained, which combine the traits of both the maternal and paternal genotypes. Analyzing the populations, promising combinations were highlighted: C. reticulata × Fortunella margarita (47.1%); C. x natsudaidai × 3252 (42.1%) and C. reticulata × C. reticulata ‘Cleopatra’ (40.9%) to create the gene pool of distant hybrids. From the mentioned combinations of crossings the greatest percent of seedlings which phenotypes tend to cultivated varieties was received. This hybrid material is a valuable source for isolating forms that are resistant to extreme environmental factors. According to phenotypic characteristics, hybrids were divided into three categories: I – Cultural, II – Semi-wild and III – Wild. Of the first category, the largest number 87 prospective forms were selected, and can be of interest for further breeding. As a result of the study of interspecific hybrid seedlings, 137 promising forms have been identified, which are carriers the complex traits such as dwarfism, thornless, early maturity and increased winter hardiness. From this set 17 genotypes were selected, which received the status of an elite forms, which successfully pass the primary test, and will be also useful in further breeding work for creating sources with a complex of positive traits and on breeding new varieties of citrus crops resistant to growing conditions.


Author(s):  
А. Kh. Chochaev

The article analyzes problems of the Russia forest complex development related to social, environmental and infrastructure issues, the solution of which is impossible without state participation. The reasons of the poor adaptation of the forest complex market economy to long development periods, as well as the environmental consequences of economic activity, including environmental pollution, depletion of natural resources, loss of biodiversity and damage to public health, are considered. The analysis of the forest complex market economy features is made on domestic and foreign examples, a serious shortcoming of which is the isolation of the investment payback process from the chosen economic development direction. Forest rejuvenation in this way leads to a decrease or even loss of the forests biospheric properties to regulate the surface runoff of atmospheric precipitation and the formation of groundwater reserves. It is known, that in the forests of the European part of Russia have been accumulated large reserves of semi-subsistence conifer and hard wood. It is shown that to involve it in use it is necessary to change the principles of annual use calculations and to actually re-develop the regulatory framework for the intermediate use of forest wood resources. Four forest management units in the forest economy of the forest complex were identified: state forest management and implementation of medium-term and long-term planning of all types of work in forests, taking into account materials of the state forest inventory and assessing the state and trends in the development of domestic and foreign timber markets; protection and protection of forests from fires and other adverse natural factors (insects, fungi, pollution); carrying out planned logging with the differentiated use of all types of wood and the organization of reforestation taking into account the diversity of growing conditions and the possibilities of using the lands of the state forest fund of Russia. It is advisable to create economic mechanisms to stimulate the activities of all enterprises and institutions of the Russia forest complex for the transition to new environmentally sound technologies in the forest. A flexible economic mechanism is needed to include forest management costs in the cost of harvested wood in order to restore the ecological, economic, social and cultural properties of forests.


Author(s):  
R. O. Mialkovskyi ◽  
◽  
V.I. Ovcharuk ◽  
P. V. Bezvikonnyy ◽  
V. S. Kravchenko V. S. ◽  
...  
Keyword(s):  

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 446d-446
Author(s):  
Beyounghan Yoon ◽  
Harvey J. Lang

Begonia × cheimantha (Christmas or Lorraine begonia) is a popular holiday crop in Europe, with certain cultivars having outstanding postharvest characteristics. Its commercial production in the southern United States has been limited by the occurrence of mottled leaf chlorosis and necrosis, apparently due to environmental stress. In this study, B. × cheimantha `Emma' was grown in the fall in a glass greenhouse at College Station, Texas, under either 0%, 60%, or 87% polyethylene shade cloth. Leaf chlorosis and necrosis was very severe on plants grown in full sun (≈650 mol·m–2·s–1), with slight chlorosis on plants under 60% shade. Plants under full sun, however, were more compact, flowered earlier, and had shorter peduncles with more flowers than those grown under shade. Reducing the vegetative long-day treatment period from 7 to 4 weeks had no effect on leaf damage development. Plants treated with paclobutrazol were shorter and had less leaf damage than untreated plants. Leaves of treated plants had a relatively higher concentration of soluble protein, chlorophyll, and enhanced activities of ascorbate peroxidase (AsA), dehydroascorbate (DHA) reductase, and monodehydro-ascorbate (MDHA) reductase than untreated plants. For Texas growing conditions, these preliminary studies indicate that B. × cheimantha should be grown under reduced light intensities, with excessive height and leaf damage being controlled with growth retardants such as paclobutrazol.


2019 ◽  
pp. 57-67
Author(s):  
T.M. Tabatskaya ◽  
N.I. Vnukova

A technique for the long-term (up to 27 years) in vitro storage of valuable birch genotypes under normal (25 °C, 2.0 klx, 16-h day and 8-h night) and low temperature (4 °C, 0.5 klx, 6-h day and 18-h night) growing conditions on hormone-free media has been described. The study explored for the first time the influence of different strategies to store the clones of Betula pubescens and B. pendula var. сarelica (6 genotypes) on the regenerative capacity of collection samples, adaptive potential of regenerated plants and plant production by the in vitro and ex vitro techniques. It was established that both storage strategies provided a persistently high survival rate (82-100%) and regenerative capacity of in vitro shoots (the multiplication coefficient of 4.2-6.3 and rhizogenic activity of 90-100%). The clones retained their characteristics of height growth under the in vitro and ex vitro conditions, and demonstrated intraclonal homogeneity and lack of signs of somaclonal variability. The plants showed substantial interspecific differences at the stage of multiplication and transfer to the greenhouse. The highest percentage of acclimated plants (75-98% depending on the clone genotype) was obtained after planting of micro plants straight in the greenhouse, which simplified the technology and made plant production less costly. long-term in vitro storage, birch, species, genotype, micropropagation, ex vitro adaptation, plant material


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