DNA-Protein Complex in Circular DNA from Phage ϕ29

THE DNA of the B. subtilis phage ?29 has been described as unpermuted linear duplex molecules¹ of molecular weight 11 × 10⁶, but the formation of circular molecules has also been indicated, suggesting the existence of cohesive ends^1,2.     

Effect of monoethanolamine salt-containing dicarboxylic acid and plant growth regulators on the absorption and accumulation of mercury

In the modern world, mercury has become an extremely dangerous pollutant due to intensive human activity. Currently, sources of mercury are wastes from chemical industries, as well as mines, oil combustion products, and household waste. Phytoextraction of heavy metals from soil is considered one of the most promising and cost-effective technologies. The efficiency of this process can be increased by introducing various amendments. The use of additives in phytoextraction can enhance the absorption of heavy metals and increase their concentration in various parts of the plant. This article presents the results of a study of various chelating agents for effective phytoextraction of mercury with white clover (Trifolium repens L.) and watercress (Lepidium sativum). In the present study, the monoethanolamine salt of dithiodiacetic acid (MEDBA) was used. The optimal concentration of MEDBA on watercress and creeping clover has been determined for highly efficient phytoextraction of mercury. Research has been carried out with a complex of exogenous growth regulators (GA / IAA / Fe-EDDHA). The results showed that the use of phytohormones and plant growth regulators led to a synergistic effect in combination with thiosulfate, but a pronounced inhibitory effect was observed with the use of MEDBA.     

两个苜蓿品种营养器官解剖结构特征比较

为了明确具有极强抗虫特性的‘草原4号紫花苜蓿’(Medicago sativa L.‘Caoyuan No.4’) 营养器官的解剖特征,该研究选择具有抗蓟马特性较强的‘草原2号杂花苜蓿’(Medicago varia Martin.‘Caoyuan No.2’)为对照,采用显微镜观察比较两品种的根、茎、叶解剖结构特征,为揭示‘草原4号紫花苜蓿’ 抗蓟马特性提供理论依据。结果显示：(1)‘草原4号紫花苜蓿’根部解剖结构的皮层薄壁细胞厚度、内皮层厚度、形成层厚度、木质部厚度和木射线宽度等5个指标均极显著高于(P＜0.01)‘草原2号杂花苜蓿’,其中木射线宽度(159.37 μm)是‘草原2号杂花苜蓿’的1.82倍。(2)‘草原4号紫花苜蓿’的茎部厚角组织厚度(21.4 μm)极显著高于‘草原2号杂花苜蓿’(P＜0.01),而韧皮部宽度、髓直径却均极显著低于‘草原2号杂花苜蓿’(P＜0.01)。(3)‘草原4号紫花苜蓿’叶片解剖构造的7个指标均极显著高于‘草原2号杂花苜蓿’(P＜0.01),其中栅栏组织层数(2～3层)极明显地高于‘草原2号杂花苜蓿’(1~2层)。研究表明,‘草原4号紫花苜蓿’的组织结构特征具有明显的抗虫特征,且其组织的抗虫特征比‘草原2号杂花苜蓿’更为突出。     

Analysis of the spectrum of ACTH-immunoreactive peptides in the brain of inbred mice

The ACTH-immunoreactive peptides (IP) distribution in the acid extract of brain and plasma fractions of C57BL/6, BALB/c and F1 (C57BL/6 X BALB/c) mice was investigated. IP were isolated by high-performance liquid chromatography. Interstrain differences in the IP spectrum were found in intact mice and mice after exposure to stress in the "open-field" test.     

Assembly of the sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures: localization by immunofluorescence of sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures

Immunofluorescent staining techniques were used to study the distribution of the Ca(2) + Mg(2+)-dependent ATPase and calsequestrin in primary cultures of differentiating rat skeletal muscle cells, grown for different periods of time under various culture conditions. In mononucleated myoblasts calsequestrin was detected after 45 h in culture whereas the ATPase was not detected until 60 h. After cell fusion began, both proteins could be identified in all multinucleated cells. Myoblasts grown for longer than 60 h in low Ca(2+) medium contained calsequestrin and the ATPase, even though they were unable to fuse. These studies at the cellular level confirm biochemical findings on the biosynthesis of calsequestrin and the ATPase. Immunofluorescent staining of myoblasts showed that calsequestrin first appears in a well-defined region of the cell near one end of the nucleus. At later times, the staining occupied progressively larger regions adjacent to the nucleus and took on a fibrous appearance. This suggests that calsequestrin first accumulates in the Golgi region and then gradually spreads throughout the cell. In contrast, the ATPase appeared to be concentrated in many small patches or foci throughout the cytoplasm and was never confined to one particular region, although some parts of the cell often stained more intensely than others. In multinucleated cells, alternating dark and fluorescent strands parallel to the longitudinal axis of the cells were evident.     

COMPARISON OF METHODS USED TO ESTIMATE NUMBERS OF WALRUSES ON SEA ICE

The US and former USSR conducted joint surveys of Pacific walruses on sea ice and at land haul-outs in 1975, 1980, 1985, and 1990. One of the difficulties in interpreting results of these surveys has been that, except for the 1990 survey, the Americans and Soviets used different methods for estimating population size from their respective portions of the sea ice data. We used data exchanged between Sovier and American scientists to compare and evaluate the two estimation procedures and to derive a set of alternative estimates from the 1975, 1980, and 1985 surveys based on a single consistent procedure. Estimation method had only a small effect on total population estimates because most walruses were found at land haul-outs. However, the Sovievr method is subject to bias that depends on the distribution of the population on the sea ice and this has important implications for interpreting the ice portions of previously reported surveys for walruses and other pinniped species. We recommend that the American method be used in future surveys. Future research on survey methods for walruses should focus on other potential sources of bias and variation.     

Abnormal and subnormal regimes of a spherical glow discharge in the drift-diffusion approximation

A spherical glow discharge with a pointlike anode is considered in a self-consistent drift-diffusion approximation. The model includes the time-dependent continuity equations for ions and electrons in the drift-diffusion approximation and Poisson’s equation for the radial electric field. In finding steady-state distributions, Ohm’s law is used to relate the discharge voltage and discharge current. Steady-state distributions of the plasma parameters across the discharge gap, current-voltage characteristics, and cathode characteristics for an abnormal spherical discharge in molecular nitrogen are obtained. In a subnormal glow-discharge regime, oscillations in the conduction current, potential, and other discharge parameters are revealed. Similar regimes are also observed in conventional discharges in tubes.     

Morphological characteristics of tissue components of different layers of the rat myocardium

The tissue components of the subendocardial, inner and outer intramural layers of the myocardium were examined by morphometry. There was no significant difference in the proportion of cardiomyocytes in the different layers of the myocardium (subendocardium 0.820 +/- 0.007; inner layer 0.713 +/- 0.100; outer intramural layers 0.727 +/- 0.008; subepicardium 0.699 +/- 0.009). The relative surface of cardiomyocytes was maximal in the subepicardium (58.62 +/- 1,18). The magnitudes of the volumetric density and surface of the capillaries decreased from the subepicardial toward the subendocardial layer. The diameter of myocytes in the test layers of the myocardium varied within a wide range.