A subset of cells in tobacco mosaic virus (TMV)-induced local lesions in <Emphasis Type="Italic">Datura stramonium</Emphasis> leaves are tolerant to TMV

Ultrastructural examination of tobacco mosaic virus-induced local lesions growing in Datura stramonium leaves is carried out. It is demonstrated that, in the central area of the lesions, the cell response to viral invasion is not uniform. Most cells exhibited an acute hypersensitive reaction (HR) and underwent rapid and complete necrosis. However, some cells, despite considerable virus accumulation and immediate contact with completely collapsed cells, maintained a certain degree of structural integrity. Analysis performed showed that the proportion of collapsed and uncollapsed cells in the lesion centre 3 to 5 days after infection essentially did not change. These data suggest that the absence of HR in some cells in the lesion centre is not due to an early stage of infection but is likely caused by cell tolerance of the virus.     

Aqueous Diaminsilver Hydroxide as a Precursor of Pure Silver Nanoparticles for SERS Probing of Living Erythrocytes

A new effective and simple preparation method of pure metallic hydrosols consisting of silver nanoparticles is proposed using aqueous diaminsilver hydroxide as a precursor freed of special reducing agents, surfactants, or anionic pollutants. The process is driven by NH₃ ligand loss and silver complex dissociation followed by silver ion reduction with hydroxyl ions or ammonia itself present in the solution. Self-reduction of aqueous diaminsilver hydroxide occurs for 20–60 min at 90–100 °C in water and results in a wide range of silver nanoparticles, with their sizes dependent on silver complex concentration and reaction time. The pure silver hydrosol is found to attach to a cell membrane without its damage thus allowing measurements of SERS spectra of submembrane hemoglobin inside living erythrocytes.     

Early Embryonic Chromosome Instability Results in Stable Mosaic Pattern in Human Tissues

The discovery of copy number variations (CNV) in the human genome opened new perspectives on the study of the genetic causes of inherited disorders and the aetiology of common diseases. Here, a single-cell-level investigation of CNV in different human tissues led us to uncover the phenomenon of mitotically derived genomic mosaicism, which is stable in different cell types of one individual. The CNV mosaic ratios were different between the 10 individuals studied. However, they were stable in the T lymphocytes, immortalized B lymphoblastoid cells, and skin fibroblasts analyzed in each individual. Because these cell types have a common origin in the connective tissues, we suggest that mitotic changes in CNV regions may happen early during embryonic development and occur only once, after which the stable mosaic ratio is maintained throughout the differentiated tissues. This concept is further supported by a unique study of immortalized B lymphoblastoid cell lines obtained with 20 year difference from two subjects. We provide the first evidence of somatic mosaicism for CNV, with stable variation ratios in different cell types of one individual leading to the hypothesis of early embryonic chromosome instability resulting in stable mosaic pattern in human tissues. This concept has the potential to open new perspectives in personalized genetic diagnostics and can explain genetic phenomena like diminished penetrance in autosomal dominant diseases. We propose that further genomic studies should focus on the single-cell level, to better understand the aetiology of aging and diseases mediated by somatic mutations.     

Behavior of crested auklets (<Emphasis Type="Italic">Aethia cristatella</Emphasis>, Charadriiformes,Alcidae) in the breeding season: Visual and acoustic displays

The crested auklet, a highly social planktivorous bird species of the Northern Pacific, is an important component of marine ecosystems. Although visual and acoustic modalities play a major role in the communication of these birds, the available data on the repertoire of their vocal signals and postures are scarce and lack quantitative analysis. This study deals with visual and acoustic displays of crested auklets on their breeding grounds and the occurrence frequencies of certain forms of social behavior in male and female birds. The data were collected on Talan Island (the Sea of Okhotsk) in 1987–1991 and 2008. They show that the rate of contacts between birds is very high and sex-specific: on average, males initiate 1.13 contacts/min, compared to 0.65 contacts/min initiated by females. Directionality of ruff-sniff displays differs depending on the posture of the recipient bird. The duration of the trumpeting display in males depends on their social surroundings. However, the duration of either the trumpeting display or the mutual cackling display during courtship is independent of the behavioral context. Vocalization of crested auklets is characterized by two independent basic frequencies occurring either sequentially or simultaneously. The role of different communicative modalities in the behavior of the crested auklet is discussed.     

Effect of ischemia in vivo and oxygen-glucose deprivation in vitro on NOS pools in the spinal cord: comparative study

1. This study was performed to compare both the Ca(2+)-dependent nitric oxide synthase (NOS) activity and the neuronal nitric oxide synthase immunoreactivity (nNOS-IR) in the rabbit lumbosacral spinal cord after 15 min abdominal aorta occlusion (ischemia in vivo) and oxygen-glucose deprivation of the spinal cord slices for 45 and 60 min (ischemia in vitro). All ischemic periods were followed by 15, 30 and 60 min reoxygenation in vitro. 2. Catalytic nitric oxide synthase activity was determined by the conversion of (L)-[(14)C]arginine to (L)-[(14)C]citrulline. Neuronal nitric oxide synthase immunoreactivity in the spinal cord was detected by incubation of sections with polyclonal sheep-nNOS-primary antibody and biotinylated anti-sheep secondary antibody. 3. Our results show that ischemia in vivo and the oxygen-glucose deprivation of spinal cord slices in vitro result in a time-dependent loss of constitutive NOS activity with a partial restoration of enzyme activity during 15 and 45 min ischemia followed by 30 min of reoxygenation. A significant decrease of enzyme activity was found during 60 min ischemia alone, which persisted up to 1 h of oxygen-glucose restoration. The upregulation of neuronal nitric oxide synthase was observed in the ventral horn motoneurons after all ischemic periods. The remarkable changes in optical density of neuronal nitric oxide synthase immunoreactive motoneurons were observed after 45 and 60 min ischemia in vitro followed by 30 and 60 min reoxygenation. 4. Our results suggest that the oxygen-glucose deprivation followed by reoxygenation in the spinal cord is adequately sensitive to monitor ischemia/reperfusion changes. It seems that 15 min ischemia in vivo and 45 min ischemia in vitro cause reversible changes, while the decline of Ca(2+)-dependent nitric oxide synthase activity after 60 min ischemic insult suggests irreversible alterations.     

Selenium distribution in eggs of avian species

We studied the effect of egg mass of eight different avian species on Se distribution between egg components and the effect of incubation on Se accumulation by chicken eggshell and shell membrane. Eight groups of birds received a diet without Se supplementation. Unfertile eggs were collected after 35 days of feeding; yolk, albumen, shell and shell membrane were assayed separately for Se. All avian species studied showed identical Se concentration in yolk–albumen complex equal to 38.7 μg Se/100 g, reflecting a linear correlation between yolk–albumen mass and Se content. Shells and shell membrane Se accumulation showed quadratic correlation with the appropriate mass thus explaining unusually high Se concentration in ostrich shell and shell membrane, that reached values 1785 and 1904 μg Se/kg respectively. Incubation of fertile eggs decreased eggshell Se content, the effect being more expressed in eggs from hens fed sodium selenite compared to organic Se utilization (Sel-Plex). It was concluded that shell might be an additional Se source for an embryo.     

Melatonin directly scavenges free radicals generated in red blood cells and a cell-free system: chemiluminescence measurements and theoretical calculations

Melatonin, a pineal secretory product, has properties of both direct and indirect powerful antioxidant. The aim of the present study was to compare the radical-scavenging, structural and electronic properties of melatonin and tryptophan, precursor of melatonin. Using the alkoxyl- and peroxyl radical-generating systems [the organic peroxide-treated human erythrocytes and a cell-free system containing the azo-initiator 2,2'-azobis(2-amidinopropane)dihydrochloride], we evaluated the radical-scavenging effects of melatonin and tryptophan. Melatonin rather than tryptophan at concentrations of 100-2000 microM markedly inhibited membrane lipid peroxidation in human erythrocytes treated with organic hydroperoxide as well as radical-induced generation of luminol-dependent chemiluminescence. The apparent Stern-Volmer constants for inhibition of membrane lipid peroxidation by melatonin and tryptophan were estimated to be (0.23+/-0.05) x 10(4) M(-1) and (0.02+/-0.005) x 10(4) M(-1), respectively. The apparent Stern-Volmer constants for inhibition of azo-initiator-derived peroxyl radical generation by melatonin and tryptophan were determined to be (0.42+/-0.05) x 10(4) M(-1) and (0.04+/-0.01) x 10(4) M(-1), respectively. The structural and electronic properties of melatonin and its precursor, tryptophan, were determined theoretically by performing semi-empirical and ab initio calculations. The high radical-scavenging properties of melatonin may be explained by the high surface area value and high dipole moment value. From the thermodynamic standpoint, based on our calculations, N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK), was the most stable end oxidative product of melatonin.     

New Insight into Erythrocyte through In Vivo Surface-Enhanced Raman Spectroscopy

The article presents a noninvasive approach to the study of erythrocyte properties by means of a comparative analysis of signals obtained by surface-enhanced Raman spectroscopy (SERS) and resonance Raman spectroscopy (RS). We report step-by-step the procedure for preparing experimental samples containing erythrocytes in their normal physiological environment in a mixture of colloid solution with silver nanoparticles and the procedure for the optimization of SERS conditions to achieve high signal enhancement without affecting the properties of living erythrocytes. By means of three independent techniques, we demonstrate that under the proposed conditions a colloid solution of silver nanoparticles does not affect the properties of erythrocytes. For the first time to our knowledge, we describe how to use the SERS-RS approach to study two populations of hemoglobin molecules inside an intact living erythrocyte: submembrane and cytosolic hemoglobin (Hb_sm and Hb_c). We show that the conformation of Hb_sm differs from the conformation of Hb_c. This finding has an important application, as the comparative study of Hb_sm and Hb_c could be successfully used in biomedical research and diagnostic tests.