Pathologic anatomy of experimental diseases of small laboratory animals caused by encephalomyocarditis virus (strain EMK-70)]

The results of pathomorphological investigation of the disease in small laboratory animals experimentally induced by the EMC-70 strain of encephalomyocarditis virus isolated from monkeys are presented. Irrespective of the mode of virus injection, the newborn and juvenile mice developed some lesions in the brown fat, transverse-striated muscles, as well as in the brain and heart. In guinea pigs the changes were characterized by the development of severe myocarditis and encephalitis accompanied by viral antigen accumulation. The disease induced by the EMC-70 strain could not be differentiated from the Coxsackie infection by the pathomorphological data. This fact should be taken into consideration in solving some problems pertinent to pathoanatomical diagnosis of viral diseases.     

Targeted genomic integration of EGFP under tubulin beta 3 class III promoter and mEos2 under tryptophan hydroxylase 2 promoter does not produce sufficient levels of reporter gene expression

Neuronal tracing is a modern technology that is based on the expression of fluorescent proteins under the control of cell type–specific promoters. However, random genomic integration of the reporter construct often leads to incorrect spatial and temporal expression of the marker protein. Targeted integration (or knock-in) of the reporter coding sequence is supposed to provide better expression control by exploiting endogenous regulatory elements. Here we describe the generation of two fluorescent reporter systems: enhanced green fluorescent protein (EGFP) under pan-neural marker class III β-tubulin (Tubb3) promoter and mEos2 under serotonergic neuron-specific tryptophan hydroxylase 2 (Tph2) promoter. Differentiation of Tubb3-EGFP embryonic stem (ES) cells into neurons revealed that though Tubb3-positive cells express EGFP, its expression level is not sufficient for the neuronal tracing by routine fluorescent microscopy. Similarly, the expression levels of mEos2-TPH2 in differentiated ES cells was very low and could be detected only on messenger RNA level using polymerase chain reaction-based methods. Our data shows that the use of endogenous regulatory elements to control transgene expression is not always beneficial compared with the random genomic integration.     

Intrinsic bursting activity in the pre-Bötzinger Complex: Role of persistent sodium and potassium currents

Computational models of single pacemaker neuron and neural population in the pre-Bötzinger Complex (pBC) were developed based on the previous models by Butera et al. (1999a,b). Our modeling study focused on the conditions that could define endogenous bursting vs. tonic activity in single pacemaker neurons and population bursting vs. asynchronous firing in populations of pacemaker neurons. We show that both bursting activity in single pacemaker neurons and population bursting activity may be released or suppressed depending on the expression of persistent sodium (I_NaP) and delayed-rectifier potassium (I_K) currents. Specifically, a transition from asynchronous firing to population bursting could be induced by a reduction of I_K via a direct suppression of the potassium conductance or through an elevation of extracellular potassium concentration. Similar population bursting activity could be triggered by an augmentation of I_NaP. These findings are discussed in the context of the possible role of population bursting activity in the pBC in the respiratory rhythm generation in vivo vs. in vitro and during normal breathing in vivo vs. gasping.     

Role of formic acid in transformation of acetic and succinic acids in animal tissues

Acetic and succinate acids KoA acyl derivatives interacting with formate were displayed to produce alpha-ketoacids--pyruvate and alpha-ketoglutarate. These acids also interact with formate and make pyruvic and malate acids, while alpha-ketoglutarate, evidently, tricarboxy acids. Interaction of formate with acetic and succinate acids inspite of occurring out of the tricarbone cycle increases the latter metabolic functions.     

Characteristic of carbohydrate components of chickens and human's fibronectins

The paper presents new information about the carbohydrate structures of 39-days chicken's fibronectin. It is found out that chicken fibronectin contains mainly biantennary N-glycans with a core fucose and fucosylated O-glycans. It is shown that N-glycans of chicken fibronectin are poorly sialated, since this protein exhibits affinity for the PNA and weak binding to sialospecific SNA. A comparative analysis of lectin-binding activity of chicken and human fibronectins has shown that both glycoproteins differ in glycan composition.     

Fibronectin-1 expression in lymphocytes of patients with erythremia

Expression of fibronectin-1 mRNA in lymphocytes in erythremia patients and healthy donors as well as fibronectin-1 concentration in plasma and its heparin-binding activity have been studied. Moreover, we also investigated the expression of fibronectin protein in lymphocytes and cell surface in erythremia disease as compared to healthy donors. It was shown that fibronectin-1 mRNA expression in lymphocytes is increased in patients with erythremia as compared to healthy donors. The decrease of plasma fibronectin concentration and its heparin-binding activity as well as the increase of lymphocyte content with surface-associated and intracellular fibronectin were revealed in erythremia disease in comparison with healthy donors. Positive correlation between plasma fibronectin level and its heparin-binding activity and negative correlation between plasma fibronectin level and quantity of lymphocytes which express fibronectin inside the cell and on cell surface was detected. Results of this investigation demonstrate that fibronectin-1 mRNA expression in lymphocytes is disturbed in erythremia disease and is accompanied by a decrease of fibronectin plasma level.     

Historical Outbreaks of Simian Hemorrhagic Fever in Captive Macaques Were Caused by Distinct Arteriviruses

Simian hemorrhagic fever (SHF) is lethal for macaques. Based on clinical presentation and serological diagnosis, all reported SHF outbreaks were thought to be caused by different strains of the same virus, simian hemorrhagic fever virus (SHFV; Arteriviridae). Here we show that the SHF outbreaks in Sukhumi in 1964 and in Alamogordo in 1989 were caused not by SHFV but by two novel divergent arteriviruses. Our results indicate that multiple divergent simian arteriviruses can cause SHF.     

A latitudinal gradient in seed nutrients of the forest herb Anemone nemorosa

The nutrient concentration in seeds determines many aspects of potential success of the sexual reproductive phase of plants, including the seed predation probability, efficiency of seed dispersal and seedling performance. Despite considerable research interest in latitudinal gradients of foliar nutrients, a similar gradient for seeds remains unexplored. We investigated a potential latitudinal gradient in seed nutrient concentrations within the widespread European understorey forest herb Anemone nemorosa L. We sampled seeds of A. nemorosa in 15 populations along a 1900-km long latitudinal gradient at three to seven seed collection dates post-anthesis and investigated the relative effects of growing degree-hours >5 °C, soil characteristics and latitude on seed nutrient concentrations. Seed nitrogen, nitrogen:phosphorus ratio and calcium concentration decreased towards northern latitudes, while carbon:nitrogen ratios increased. When taking differences in growing degree-hours and measured soil characteristics into account and only considering the most mature seeds, the latitudinal decline remained particularly significant for seed nitrogen concentration. We argue that the decline in seed nitrogen concentration can be attributed to northward decreasing seed provisioning due to lower soil nitrogen availability or greater investment in clonal reproduction. This pattern may have large implications for the reproductive performance of this forest herb as the degree of seed provisioning ultimately co-determines seedling survival and reproductive success.