scholarly journals PHYSICAL CHEMICAL STUDIES ON THE SPECIFIC INTERACTION OF AN ACRIFLAVINE-PHOSPHOTUNGSTIC ACID COMPLEX WITH DOUBLE-STRANDED NUCLEIC ACIDS

1970 ◽  
Vol 47 (2) ◽  
pp. 500-511 ◽  
Author(s):  
Charles T. Ladoulis ◽  
Thomas J. Gill
Keyword(s):  
Organic Cation ◽  
Phosphotungstic Acid ◽  
Physiological Activity ◽  
Specific Interaction ◽  
Genetic Material ◽  
Acid Complex ◽  
Dna And Rna ◽  
Physical Chemical ◽  
Chemical Studies ◽  
Definition Of

The detailed definition of the structure of DNA in chromosomes and in interphase chromatin is important for correlating the structure of the genetic material with various states of physiological activity. A general approach to developing specific reagents for a variety of such studies in solution and in tissues is to combine a chemically specific organic cation with the electron-opaque phosphotungstic acid (PTA) molecule. The reagent described in this paper was made from the interaction of acriflavine and phosphotungstic acid. The acriflavine-PTA complex (a) displays some unique absorption and fluorescence properties, (b) binds specifically to DNA and RNA by intercalation of the acriflavine moiety, and (c) is electron opaque. In addition, it binds to double-stranded synthetic polynucleotides, but not to a variety of proteins, nucleoproteins, or polysaccharides.

Ultramicro Automated Screening Method for Uric Acid

1967 ◽  
Vol 13 (11) ◽  
pp. 985-993 ◽  
Author(s):  
Ronald H Laessig ◽  
Chester E Underwood ◽  
Barbara J Basteyns
Keyword(s):  
Uric Acid ◽  
Phosphotungstic Acid ◽  
Screening Method ◽  
Sampling Procedure ◽  
Blood Capillary ◽  
Acid Complex ◽  
Blood Uric Acid ◽  
Precision And Accuracy ◽  
Automated Screening

Abstract An automated colorimetric microprocedure, suitable for screening purposes, has been developed for the determination of blood uric acid levels. The method uses 2O-µl. whole-blood (capillary) samples and is based on the AutoAnalyzer measurement of the absorbance of the colored uric acid-phosphotungstic acid complex. The dilution inherent in the sampling procedure necessitated a modification of the existing AutoAnalyzer method to increase the sensitivity. The proposed method is evaluated for precision and accuracy by comparison with the standard AutoAnalyzer macro-method.

scholarly journals PHYSICAL CHEMICAL STUDIES OF THE SURFACTANT DILAURYLDIMETHYLAMMONIUM BROMIDE (DLDMAB): AGGREGATION AND CATALYTIC PROPERTIES

2009 ◽  
Vol 17 (17) ◽  
pp. 21-32
Author(s):  
Elizabeth Fatima de Souza ◽  
Silvia Dani ◽  
Lavinel G. IONESCU
Keyword(s):  
Thermodynamic Parameters ◽  
Catalytic Properties ◽  
Activation Parameters ◽  
Critical Micellar Concentration ◽  
Physical Chemical ◽  
Chemical Studies ◽  
Diphenyl Phosphate ◽  
C 32 ◽  
Free Energy Of Micellization ◽  
Hydrolysis Of

The micellization of dilauryldimethylammonium bromide (DLDMAB) in water was studied by using surface tension measurements. The critical micellar concentration (CMC) was determined at 25°C, 32°C and 40°C and thermodynamic parameters such as the free energy of micellization (∆G°mic), enthalpy (∆H°mic), and entropy (∆S°mic) of micellization were measured. The CMC at 25°C was 4.93 x 10-5 M and the corresponding values of the thermodynamic parameters were: ∆G°mic = -5.87 kcal/mol; ∆H°mic = -1.12 kcal/mol and ∆S°mic = +16.00 e.u. Micelles of the surfactant DLDMAB act as catalysts for the alkaline hydrolysis of p-nitrophenyl diphenyl phosphate (NPDPP) with a maximum catalytic factor of approximately 120 compared to 80 for CTAB. Typical activation parameters measured for 1.00 x 10-3 M surfactant and 0.005 M NaOH were: Ea = 9.7 kcal/mo/; ∆H°≠ = 9.1 kcal/mol; ∆G°≠ = 19.6 kcal/mol and ∆S°≠ = -33.9 e.u. The kinetic results were also analyzed in terms of the pseudo-phase ion-exchange models (PPIE) and showed that the model is applicable to describe the experimental results.

scholarly journals ECOLOGICAL STATE OF THE ILI BASIN GEOSYSTEMS

2021 ◽  
Vol 74 (2) ◽  
pp. 78-85
Author(s):  
T. A. Bazarbayeva ◽  
◽  
B.D. Rakhyshova ◽  
A. A. Oshakbay ◽  
◽  
...  
Keyword(s):  
Water Resources ◽  
River Water ◽  
Rapid Development ◽  
Geographical Location ◽  
Mineral Fertilizers ◽  
Chemical Studies ◽  
Spring Flow ◽  
Ili River Basin ◽  
Definition Of

The article considers the geo-ecological situation of the Ili basin. The definition of the physical and geographical location, topography, soil and vegetation of the region was given. It was determined that the management of the efficient use of water resources in the Ili river basin depends primarily on the water resources of the rivers entering the basin and the level of Lake Balkhash. Factors determining the spring flow of the Ili River are shown. Due to the development of the middle reaches of the Ili River, the whole river ecosystem, rice fields and shangel massifs, excessive use of mineral fertilizers and chemicals has led to a decrease in the quality of river water. In addition to the shortage of water resources, anthropogenic measures related to the rapid development of agriculture affect the quality of river water. Physical and chemical studies of water samples taken from the Ili River were carried out. It was clearly observed that the content of trace elements of zinc, lead and iron in water is higher than the approved maximum allowable concentration. According to the results of the study, the effect of micronutrients on the human body was considered.

The Biology of Bacteria

2019 ◽  
Author(s):  
Armine Sefton
Keyword(s):  
Cell Wall ◽  
Bacterial Infections ◽  
Genetic Material ◽  
Gram Positive ◽  
Dna And Rna ◽  
Gram Staining ◽  
Genetic Features ◽  
Potential Pathogen ◽  
A Cell ◽  
Micro Organisms

Bacterial infections and infestations of man can be caused by both microbes and non-microbes. Microbes include bacteria, viruses, fungi, and protozoa. Non-microbes include worms, insects, and arachnids. This chapter concentrates on the basic biology of bacteria. A pathogen is an organism that is able to cause disease in its host and the pathogenicity of any organism is its ability to produce disease. Microbes express their pathogenicity by means of their virulence. The virulence of any pathogen is determined by any of its structural, biochemical, or genetic features that enable it to cause disease in the host. The relationship between a host and a potential pathogen is non- static; the likelihood of any pathogen causing disease in its host depends both on the virulence of the pathogen and the degree of resistance or susceptibility of the host, due mainly to the effectiveness of the host’s defence mechanisms. Two of the main factors influencing a bacteria’s pathogenicity are its ability to invade and it ability to produce toxins—either exotoxins or endotoxins. Bacteria are unicellular prokaryotic micro-organisms, unlike human cells, which are eukaryotic. Fungi, protozoa, helminths, and arthropods are also eukaryotic. Prokaryotic organisms contain both DNA and RNA, but their genetic material exists unbound in the cytoplasm of the cell as, unlike eukaryotic cells, they have no nuclear membrane. Sometimes bacteria contain additional smaller circular DNA molecules, called plasmids. The main features of a bacterium are the cell wall, cytoplasm, and cell membrane. However, some bacteria have additional features such as spores, capsules, fimbriae (pili), and flagellae. The construction of the cell wall is different in different bacteria, but all cell walls contain peptidoglycan. The structure of the cell wall determines the staining characteristics when stained using the Gram stain. Although its first use was over a hundred and fifty years ago, is still the standard method for primary classification of bacteria. Occasionally, bacteria do not have a cell wall. Gram staining of a fixed smear of bacteria is used to separate bacteria into Gram positive or Gram negative, and also to demonstrate their shape. Bacteria with a thick peptidoglycan layer but with no outer membrane stain purple and are called Gram positive.

Physical chemical studies of short-chain lecithin homologues. I.

1974 ◽  
Vol 1 (3) ◽  
pp. 175-183 ◽  
Author(s):  
R.J.M. Tausk ◽  
J. Karmiggelt ◽  
C. Oudshoorn ◽  
J.Th.G. Overbeek
Keyword(s):  
Short Chain ◽  
Physical Chemical ◽  
Chemical Studies

Some Physical Chemical Studies with Heteropoly Acids.

1955 ◽  
Vol 59 (10) ◽  
pp. 1074-1076 ◽  
Author(s):  
Melvin C. Baker ◽  
Philip A. Lyons ◽  
S. J. Singer
Keyword(s):  
Heteropoly Acids ◽  
Physical Chemical ◽  
Chemical Studies

Genotype×environment interactions and some considerations of their implications for wheat breeding in Australia This review is one of a series commissioned by the Advisory Committee of the Journal.

1998 ◽  
Vol 49 (2) ◽  
pp. 153 ◽  
Author(s):  
K. E. Basford ◽  
M. Cooper
Keyword(s):  
Genetic Material ◽  
Wheat Breeding ◽  
Breeding Programs ◽  
Specific Adaptation ◽  
New Concepts ◽  
Statistical Studies ◽  
Definition Of ◽  
Level Of Understanding ◽  
The Impact

Genotype×environment (G×E) interactions complicate selection forbroad adaptation, while their nature and causes need to be understood toutilise and exploit them in selection for specific adaptation. This invitedreview combines an assessment of the literature with the experience we havegained from involvement in wheat breeding and associated research programs toassess (1) the implications of G×E interactions for wheat breeding inAustralia, (2) the impact that research into G E interactions has had onbreeding strategy, and (3) the evidence for impact from this research efforton genetic improvement of crop adaptation. The role of analytical methodologyin this process is considered and some important issues are discussed.There are sufficient examples drawn from wheat breeding in Australia tosuggest that progress in dealing with G×E interactions can be made andseveral of these are presented. They show that impact in plant breedingfollows from achieving an appropriate level of understanding of theenvironmental and genetic factors causing the interactions as well as anassessment of their importance in the target genotype-environment system. Anaccurate definition of the environmental factor(s) contributing to theG×E interactions has been particularly important in determining therelevance of observed differences in plant adaptation to the target populationof environments. From the combination of biological and statistical studies, amore comprehensive understanding of G×E interactions has emerged andcontributed to new concepts and procedures for dealing with them.Distinguishing between what are repeatable and non-repeatable interactions isa key step. Genuine cases of positive specific adaptation observed inmulti-environment trials (METs) can be exploited by appropriately targetedselection strategies, while non-repeatable interactions are accommodated byselection for broad adaptation.The investigation of G×E interactions for grain yield of wheat inAustralia has matured to the point where an understanding of some of theircauses has enabled wheat breeders to exploit positive components of specificadaptation. The experience that has been gained in achieving these advancesindicates the importance of establishing a MET system that is relevant to thetarget population of environments of the breeding program. The investment ofadequate resources into effective design, conduct, analysis, andinterpretation of METs remains critical to continued progress from selectionin complex genotype-environment systems that present large G× Einteractions. Wheat breeders who understand their genetic material and thetarget population of environments can then use the generated information baseto achieve impact from their breeding programs.

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