Mechanism of FtsZ assembly dynamics revealed by filament structures in different nucleotide states

Treadmilling protein filaments perform essential cellular functions by growing from one end while shrinking from the other, driven by nucleotide hydrolysis. Bacterial cell division relies on the primitive tubulin homolog FtsZ, a target for antibiotic discovery that assembles into single treadmilling filaments that hydrolyse GTP at an active site formed upon subunit association. We determined high-resolution filament structures of FtsZ from the pathogen Staphylococcus aureus in complex with different nucleotide analogues and cations, including mimetics of the ground and transition states of catalysis. Together with mutational and biochemical analyses, our structures reveal interactions made by the GTP γ-phosphate and Mg2+ at the subunit interface, a K+ ion stabilizing loop T7 for co-catalysis, new roles of key residues at the active site and a nearby crosstalk area, and rearrangements of a dynamic water shell bridging adjacent subunits upon GTP hydrolysis. We propose a mechanistic model that integrates nucleotide hydrolysis signalling with assembly-associated conformational changes and filament treadmilling. Equivalent assembly mechanisms may apply to more complex tubulin and actin cytomotive filaments that share analogous features with FtsZ.

Kosmotropic anion for improving cycling stability of aqueous lithium-ion batteries in salt-in-water electrolytes

The incompatibility between Li+-intercalated electrodes and water limits the practical feasibility of aqueous lithium-ion batteries (LIBs), which are economical and environmentally benign energy storage systems. Tremendous amounts of salts dissolved in water (water-in-salt) have been utilized to mitigate the access of water to the electrode/electrolyte interface and to extend the electrochemical potential window of aqueous LIBs. However, this approach has low viability owing to the expense of the salts. Here, we show that kosmotropic anions with moderate concentrations (0.5 ~ 3 mol kg− 1) protect the LiCoO2 electrode by harnessing water molecules. The sulfates of kosmotropic anions develop rigid water-solvation shells and also form ion pairs with Li+. All-atomic-level multiscale simulation revealed that sulfates tied with Li+ and the water shell are highly concentrated at the interface, thus decreasing the density of free water. The suppressed water activity explains the superior cell performance achieved with 0.5 mol kg− 1 sulfate relative to that in cells with 1 mol kg− 1 of chaotropic anions such as nitrate, perchlorate, and bis(trifluoromethylsulfonyl)imide. The formation of a liquid-phase protective layer is a new concept for developing stable aqueous batteries without the requirement for a solid-state electrolyte or an artificial protective layer on the electrode.

NUMERICAL SIMULATION OF SHELL AND TUBE HEAT EXCHANGER IN ANSYSFLUENT SOFTWARE

Numerical modeling of a water-to-water shell-and-tube heat exchanger using the capabilities of mathematical modeling by means of a fi nite element analysis package is considered. An algorithm for solving problems of heat and mass transfer in the ANSYSFluent software product is proposed. A distinctive feature of this algorithm is the simplicity and accuracy of the calculations. In the course of the study, the contours of the velocity and temperature distribution in the heat exchanger were obtained, and the data obtained using computer modeling were verifi ed with an analytical solution.

Nijhoff. — Ein neues Verfahren zur Behandlung der Placenta praevia centralis. (Centralbl. F. Gynaek., 1895, No. 8). A new way of giving birth with a central presentation of the placenta

At the end of pregnancy, with bleeding, when the patient had not yet missed a finger, the author made a tamponation of the cervix and vagina. The pharynx opened by 2 fingers, the bleeding continued. Then the author made a gap (linear) in the presenting part of the last, without violating the integrity of the water shell. The last one, straining to raise the influence of contractions, acted on further expansion of the pharynx.

EFFECT OF FRESH WATER SHELL (BATISSA VIOLACEA CELEBENSIS) ON IRON LEVEL IN THE GROUND WATER, KENDARI, SOUTH EAST SULAWESI

Background: Iron in rural ground water supplies is a common problem: its concentration level ranges from 0 to 50 mg/L, while WHO recommended level is <0.3 mg/L.The iron occurs naturally in the aquifer but levels in groundwater can be increased bydissolution of ferrous borehole and handpump components. Iron-bearing groundwater is often noticeably orange in colour, causing discoloration of laundry, and has anunpleasant taste, which is apparent in drinking and food preparation. There are only afew studies of fresh water shell (batissa violacea celebensis) as an alternative to reducethe iron content in groundwater has not been done much.This study aimed to to testthe effectiveness of fresh water shell (batissa violacea celebensis) in decreasing ironlevel in the ground water.Subjects and Method: This was a quasi-experiment study before and after with nocontrol design conducted at Wowawanggu village, Wua-wua sub-district, Kendari,South Sulawesi. A total sample of 3 boreholes was selected for this study by purposivesampling. The dependent variable was iron level in the ground water. The independent variable was fresh water shell (batissa violacea celebensis). Differences in meanbetween groups were tested by One Way ANOVA and post hoc test.Result: Differences in mean between groups were statistically significant with ironlevel in the ground water in the fresh water shell (batissa violacea celebensis) groupslower than the negative control group.Conclusion: Fresh water shell (batissa violacea celebensis) is effective to decreaseiron level in the ground water.

Accumulation of heavy metals by family Lymnaeidae representatives as response to anthropogenic pollution critical levels of South Ural reservoirs

The features of heavy metals accumulation by Lymnaea fragilis and L . psilia were researched for the aerate emission polluted area of Karabash copper-smelting manufacturing (Southern Ural). These features are concluded with selective redistribution of heavy metals between soft tissues and the shell of Lymnaea . The heavy metals accumulation takes place by three independent tendencies: water soft tissues, water shell and soft tissues shell. The heavy metals content levels a thousand times exceed the physiological norm in soft tissues while in shell they exceed manifold. In the first place manganese and iron are accumulated while the cobalt, cadmium and molybdenum are finalizing the researched rank of accumulation. It has been ascertained that more biophil manganese are accumulated in mollusk soft tissues more than in other metals, while slightly less biophil iron is accumulated in shell, mainly in surface layers. For soft tissues and shell different ranks of heavy metals accumulation are observed, but these ranks are similar for different habitats, thus qualitative biogeochemical similarity is observed. The heavy metals accumulation in the system water soft tissues shell can help to estimate the extent of the metal environment pollution as well as local biophility of this metal. The adaptive response of pond snails to anthropogenic pollution is that there are more of them in less polluted reservoirs and less in more polluted reservoirs. It has been confirmed, that high heavy metals concentration and low pH level in reservoirs leads to death and absolute absence of these mollusk species.

Behavioural inferences from Late Pleistocene Aboriginal Australia

Detailed research into marsupial behavioural ecology and modelling of past Aboriginal exploitation of terrestrial fauna has been scarce. Poor bone preservation is one limiting factor in Australian archaeological sites, but so has been the lack of research concerning the ecology and physiology of Australia’s endemic fauna. Much research has focused on marine and fresh-water shell-fish found in coastal and inland midden sites. Detailed studies into areas such as seasonality of past human occupation and nutritional returns from terrestrial prey species have not had the same attention. This chapter reviews the current level of published Australian research into two aspects of faunal studies, seasonality and nutrition. It describes the patterns from well-researched faunal data excavated from the Ice Age sites in southwest Tasmania. Concentration is on the vertebrate fauna found in seven limestone cave sites to examine any temporal changes to seasonal butchery and identify any differences between seasonally occupied sites.

The electric conductivity characteristics of seawater ionic solution under the influence of magnetic field

The electric conductivity of magnetized and unmagnetized seawater ionic solutions was measured by impedance analyzer (4294A, Agilent Technologies) at 12[Formula: see text]C, 1 KHz. A new relationship model of conductivity and concentration has been established, which fitted both magnetized and unmagnetized samples and was suitable for all the solutions whether at low concentration or at high concentration. Meanwhile, it was found that the magnetic field effect on the conductivity of solution is to some extent due to the changes of thickness and order of water shell around the ion.