Phylogenetic Analysis of Genes Responsible for the Primary and Secondary Response of Sinorhizobium meliloti Towards Salinity Stress | Chapter 2 | Research Advances and Challenges in Agricultural Sciences Vol. 6

The nodule bacteria Sinorhizobium meliloti are mutualistic symbionts of alfalfa, which has a wide area of distribution, including the zone of arid agriculture, the soils of which are subject to salinization. S. meliloti, as typical saprophytes, are found in soils of different types and degree of salinity. Therefore, rhizobia must have a gene pool that determines their ability to adapt to different conditions. This paper presents the first results of phylogenetic analysis of genes involved in primary and secondary responses to the stress factor salinity. Analysis of 26 S. meliloti strains for which full genomic data are available showed that the pSymA replicon, on which the genes essential for symbiotic nitrogen-fixing activity are localized, also plays a significant role in the formation of the gene pool associated with tolerance to salinity stress. The identification of the closest putative phylogenetic relatives for all 14 genes studied allowed, for the first time, to gain insight into the evolutionary pathway of stress-related gene pool formation in nodule bacteria forming nitrogen-fixing symbiosis with leguminous plants.

Author(s) Details:

Victoria Spartakovna Muntyan,
Laboratory of Genetics and Selection of Microorganisms, Federal State Budget Scientific Institution All-Russia Research Institute for Agricultural Microbiology (FSBSI ARRIAM), 196608 Saint Petersburg, Russia.

Marina Lvovna Roumiantseva,
Laboratory of Genetics and Selection of Microorganisms, Federal State Budget Scientific Institution All-Russia Research Institute for Agricultural Microbiology (FSBSI ARRIAM), 196608 Saint Petersburg, Russia.

Please see the link here: https://stm.bookpi.org/RACAS-V6/article/view/14144

Nucleolar Organizer Region (NOR) Polymorphism in Some Indian Anuran Amphibian | Chapter 12 | Advanced Research in Biological Science Vol. 8

 The amphibians are the first vertebrate class to colonize the terrestrial environment from the aquatic environment, originating from Crossopterygian fishes in the late Devonian period. They have been the subject of various investigations because of their position in the phylogenetic history, morphological peculiarity, low diploid chromosome number with elongated metaphase chromosome and controversial nature of sex determination. The Indian subcontinent is rich in amphibian fauna. Still, the cytogenetical studies, particularly the karyomorphological study about the distribution of constitutive heterochromatin and nucleolar organizer region (NOR), need to be more detailed. The present book chapter has, therefore, been oriented to describe Amphibia's biology briefly. In addition, cytogenetics of Amphibia with particular reference to constitutive heterochromatin distribution and nucleolar organizer region polymorphism in some Indian anurans such as bufonids, ranids and rhacophorids were written.

 

Conventional staining of mitotic metaphase stages of Bufonid species studied possess symmetrical karyotypes with 2n= 22 and NF = 44. The Ranid and Rhacophorid species the author studied possess symmetrical karyotypes with 2n= 26 and NF = 52. Interestingly, nucleolar organizer region or secondary constriction (SC) region staining by HCl-trypsin digestion and AgNO3 or N-banding technique showed that the number, size and position of NORs are variable in the different species as well in different individuals of the same species. NOR heteromorphism concerning size was also noted between homologous chromosomes of some individuals. The NOR heteromorphism about intraspecific and interspecific variability in size, number and location of chromosomes is very interesting. It would be helpful to solve the phylogenetic relationship among the different species of amphibians.

Author(s) Details:

Samarendra Nath Banerjee,
Department of Zoology, Rammohan College, 102/1 Raja Rammohan Sarani, Kolkata – 700009, West Bengal, India.

Please see the link here: https://stm.bookpi.org/ARBS-V8/article/view/13619

The “Magic” Zeolites | Book Publisher International

 Zeolites fascinate us not just because of their beauty but also because of their structural diversity. Zeolites are another commonly utilised mineral with a variety of applications. Their ability to act at the cellular level by trapping heavy metals and poisons and safely eliminating them from the body is extremely significant. Clinoptilolite, a mineral belonging to the Zeolite group, is renowned as one of the best adsorbers. In a 90-day ecotoxicological experiment with laboratory mice, the clinoptilolite sorbent KLS–10-MA was used. On the basis of natural Bulgarian zeolite, this sorbent was created. As a toxin, lead (Pb) was used. The animals were divided into four groups, each with 60 specimens: Group 1 (control): animals fed conventional small rodent food and water; Group 2: animals fed conventional food + clinosorbent KLS-10-MA and water; Group 3: animals fed conventional food and water + Pb(NO3)2; Group 4: animals fed conventional food + KLS-10-MA and water + Pb(NO3)2; Group 5: animals fed conventional food + KLS-10-MA and water + Pb(NO3)2; Group 6: animals fed conventional food + KLS-10-MA (NO3) 2.

In the Pb-exposed mice, chromosome abnormalities, a decrease in the mitotic index, pathological erythrocytes, a drop in erythropoesis, and a loss of body weight were found as a result of a well-expressed toxicological stress.

In exposed and supplemented mice, dietary inclusion of the clinoptilolite sorbent reduced Pb concentrations in carcass, liver, kidneys, bones, and faeces by 84 percent, 89 percent, 91 percent, 77 percent, and 88 percent, respectively. Pb-exposed and clinoptilolite-supplemented mice had 2.3-fold lower chromosome aberrations frequency, 2.5-fold higher mitotic index, 1.5-fold higher percentage normal erythrocytes, 3.14-fold more proliferating erythrocytes, and 1.3-fold higher body weight on day 90 compared to Pb-exposed and non-supplemented mice. After day 40, the supplemented animals' mitotic index increased.

The sorbent is practically non-toxic, and its use is neither harmful to animals nor harmful to the environment.

A quantitative approach is also critical for an in-depth investigation of the dynamics of lead bioaccumulation and the organism's reactions to chronic intoxication.

The general tendencies of Pb kinetics in bones were outlined using a mathematical model. The coefficient of apsorption of Pb by gastrointestinal mucosa in supplemented mice was reported to be = 3.53 percent based on the model. The non-supplemented animals have the same coefficient of = 15%.

A mathematical model for the variation of the mitotic index with time was developed for the first time. This model demonstrates that animal recovery processes occur in tandem with Pb bioaccumulation, and that during the experiment, the susceptibility of the mouse's organism to Pb load reduces as the pace of genetic apparatus recovery grows.

In fact, zeolites exhibit "magical" properties and define genuine prospects for developing new therapeutic medications in cases of chronic intoxication based on modified natural clinoptilolites.

Author(S) Details

Svetla E. Teodorova
Research Fellow Physics and Biophysics, Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Bulgaria.

View Book:- https://stm.bookpi.org/TMCZ/article/view/3368