Structural and functional organization of the colicin operon in the ColD-CA23 plasmid

The organization of the genes involved in colicin D synthesis was studied. These are colicin, immunity and lysis genes. The nucleotide sequence of the immunity gene, its structural and regulatory regions were determined. This gene was shown to be located next to the colicin gene on the same strand and followed by the lysis gene. When colicin synthesis is induced with mitomycin C the immunity gene is transcribed from the general SOS-dependent promotor as a part of the colicin operon. However it has its own SOS-independent promotor in normal growth conditions. A high homology in amino acid sequences of Co1D lysis protein and that of Co1E1, Co1E2, Co1E3, Co1DF13, Co1A was revealed. A detailed scheme of Co1D-CA23 colicin operon structural organization is suggested.     

Neural Crest—An Unusual Population of Embryonic Cells

Molecular Biology - The neural crest (NC) in embryos of vertebrates represents a cell population formed at the border of the neural plate. These cells retain pluripotency, express a set of specific...     

To the Academician Alexander Spirin 90th Anniversary from Informosomes to the World of mRNP

Doklady Biochemistry and Biophysics - The main stages and achievements in the investigation of the fate of mRNA in eukaryotic cells, which began half a century ago with the discovery of...     

The role of stress proteins HSP70 and the adrenergic system in different resistance to myocardial infarction of August and Wistar genetic rat strains]

A lesser resistance against myocardial infarction (MI) in the Wistar rats as compared with the August rats was found to be combined with a greater stress-response and activation of the heart sympathetic regulation in the former rats. In the Wistar rats and not in August rats, an activation of hypothalamic noradrenaline (NA) system occurs as well as a greater "output" of the NA from sympathetic terminals in the myocardium. Accumulation of the HSP 70 stress-proteins in IM in the myocardium is nearly 2-2.5-fold lesser in the Wistar rats. Thereupon, different resistance against the IM in Wistar and August rats seems to be due to a genetically determine differences in intensity of the stress-response, activation of the heart sympathetic regulation in the IM, and production of the HSP 70 protective stress-proteins in the myocardium.     

Inherent efficiency of stress-limiting systems as a factor of the resistance to stress-induced disorders

A hypothesis is substantiated in accordance to which a resistance of an organism to stress damages depends upon genetically determined peculiarities of its regulatory stress-limiting systems that restrict stress reaction and its detrimental effects. A comparison of differences between the stress resistance and the activity of the stress-limiting systems (dopaminergic, serotoninergic, nitric oxide and heat shock proteins systems) in rats of two strains August and Wistar indicates that the higher hereditary activity of mentioned systems is associated with the higher resistance to acute emotional stress; and the lower hereditary activity of these systems associated with the lower resistance to this stress. At the same time the adaptation to repeated non-damaging exposures to stressor aimed to rise the stress resistance leads to opposite results in rats of the mentioned strains. In the animals with the higher hereditary resistance to acute stress (August rats) the adaptation reduces this resistance. In the animals with the lower hereditary stress resistance (Wistar rats) that sort of adaptation really rises this resistance. That is determined by changes in activity of the stress-limiting systems during repeated stress exposures. In the animals with the higher hereditary activity of the stress-limiting systems the adaptation reduces the activity of these systems. In the animals with the lower hereditary activity of the stress-limiting systems the adaptation rises this activity and the resistance of these animals to stress damages.     

Variants in the interleukin-1 alpha and beta genes,and the risk for periodontal disease in dogs

Elevated levels of interleukin-1 (IL-1) have been shown to amplify the inflammatory response against periodontopathogenic bacteria. In humans, polymorphisms in the IL1A and IL1B genes are the most well-studied genetic polymorphisms associated with periodontal disease (PD). In contrast to human, there is a lack of knowledge on the genetic basis of canine PD. A case–control study was conducted in which a molecular analysis of dog IL1A and IL1B genes was performed. Of the eight genetic variants identified, seven in IL1A gene and one in IL1B gene, IL1A/1_g.388A >C and IL1A/1_g.521T >A showed statistically significant differences between groups (adjusted OR (95% CI): 0.15 (0.03–0.76), P= 0.022; 5.76 (1.03–32.1), P= 0.046, respectively). It suggests that in the studied population the IL1A/1_g.388C allele is associated with a decreased PD risk, whereas the IL1A/1_g.521A allele can confer an increased risk. Additionally, the IL1A/2_g.515G >T variation resulted in a change of amino acid, i.e. glycine to valine. In silico analysis suggests that this change can alter protein structure and function, predicting it to be deleterious or damaging. This work suggests that IL1 genetic variants may be important in PD susceptibility in canines.     

Testing the quick meal hypothesis: The effect of pulp on hoarding and seed predation of Hymenaea courbaril by red‐rumped agoutis (Dasyprocta leporina)

Abstract: Red‐rumped agoutis (Dasyprocta leporina) are important seed dispersers/predators of Neotropical large‐seeded plants. Several species of seeds cached by agoutis have an edible reward, in contrast to temperate rodent‐dispersed diaspores. The quick meal hypothesis states that the presence of a reward such as edible pulp will enhance the efficiency of rodents as seed disperses by satiating the animal and, consequently, reducing seed predation and enhancing hoarding. In this study, this hypothesis was tested using as the reference system the pulp and seeds of Hymenaea courbaril. Seeds with and without pulp were offered to agoutis and the behaviour of each individual was recorded. Since the probability of predation and hoarding were complementary, we used the probability of predation. The proportion of agoutis that preyed on at least one seed was similar for seeds with (42.8% of individuals) and without (40.0% of individuals) pulp. In agoutis that preyed upon at least one seed, the probability that they killed a seed did not differ between seeds with (0.17 ± 0.03) and without (0.20 ± 0.08) pulp. Hence, these results do not support the ‘quick meal hypothesis’.     

Extrafloral nectaries as a deterrent mechanism against seed predators in the chemically protected weed Crotalaria pallida (Leguminosae)

Abstract In several plants, extrafloral nectaries (EFN) are located close to the reproductive structures, suggesting that ants may act as a defence against specialized seed predators that overcome chemical defences. Alternatively, ants may also deter herbivores in a generalized manner, thereby protecting the whole plant. In this work, we examined the relationship between the chemically protected weed Crotalaria pallida Ait. (Leguminosae) that bears EFN, its specialized seed predator, the larvae of the arctiid moth Utetheisa ornatrix L. (Arctiidae) and ants. We tested two hypotheses related to the type of deterrence caused by ants. The Seed Predator Deterrence Hypothesis predicts that ant deterrence is directed primarily towards herbivores that destroy seeds and other reproductive structures, without attacking herbivores on vegetative structures. The General Deterrence Hypothesis states that ants are general in their effects, equally deterring herbivores in vegetative and reproductive structures. Our results supported the predictions of the Seed Predator Deterrence Hypothesis, namely, that (i) ant activity on EFN was related to the vulnerability of reproductive structures to attack by U. ornatrix; (ii) ant patrolling was restricted almost entirely to racemes; (iii) ants removed termites used as baits more frequently on racemes than on leaves; and (iv) U. ornatrix larvae were often expulsed from the racemes. These results indicate that EFN can act as another deterrent mechanism in chemically protected plants by promoting the expulsion of specialist seed predators.