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Abstract The development of artificial cells has led to fundamental insights into the functional processes of living cells while simultaneously paving the way for transformative applications in biotechnology and medicine. A common method of generating artificial cells is to encapsulate protein expression systems within lipid vesicles. However, to communicate with the external environment, protein translocation across lipid membranes must take place. In living cells, protein transport across membranes is achieved with the aid of complex translocase systems which are difficult to reconstitute into artificial cells. Thus, there is need for simple mechanisms by which proteins can be encoded and expressed inside synthetic compartments yet still be externally displayed. Here we present a genetically encodable membrane functionalization system based on mutants of pore-forming proteins. We modify the membrane translocating loop of α-hemolysin to translocate functional peptides up to 52 amino acids across lipid membranes. Full membrane translocation occurs in the absence of any translocase machinery and the translocated peptides are recognized by specific peptide-binding ligands on the opposing membrane side. Engineered hemolysins can be used for genetically programming artificial cells to display interacting peptide pairs, enabling their assembly into artificial tissue-like structures.

Cardiac hypertrophy resulting from sympathetic nervous system activation triggers the development of heart failure. The transcription factor Y-box binding protein 1 (YB-1) can interact with transcription factors involved in cardiac hypertrophy and may thereby interfere with the hypertrophy growth process. Therefore, the question arises as to whether YB-1 influences cardiomyocyte hypertrophy and might thereby influence the development of heart failure. YB-1 expression is downregulated in human heart biopsies of patients with ischemic cardiomyopathy (n = 8), leading to heart failure. To study the impact of reduced YB-1 in cardiac cells, we performed small interfering RNA (siRNA) experiments in H9C2 cells as well as in adult cardiomyocytes (CMs) of rats. The specificity of YB-1 siRNA was analyzed by a miRNA-like off-target prediction assay identifying potential genes. Testing three high-scoring genes by transfecting cardiac cells with YB-1 siRNA did not result in downregulation of these genes in contrast to YB-1, whose downregulation increased hypertrophic growth. Hypertrophic growth was mediated by PI3K under PE stimulation, as well by downregulation with YB-1 siRNA. On the other hand, overexpression of YB-1 in CMs, caused by infection with an adenovirus encoding YB-1 (AdYB-1), prevented hypertrophic growth under α-adrenergic stimulation with phenylephrine (PE), but not under stimulation with growth differentiation factor 15 (GDF15; n = 10–16). An adenovirus encoding the green fluorescent protein (AdGFP) served as the control. YB-1 overexpression enhanced the mRNA expression of the Gq inhibitor regulator of G-protein signaling 2 (RGS2) under PE stimulation (n = 6), potentially explaining its inhibitory effect on PE-induced hypertrophic growth. This study shows that YB-1 protects cardiomyocytes against PE-induced hypertrophic growth. Like in human end-stage heart failure, YB-1 downregulation may cause the heart to lose its protection against hypertrophic stimuli and progress to heart failure. Therefore, the transcription factor YB-1 is a pivotal signaling molecule, providing perspectives for therapeutic approaches.

An isotope synthesis of 1257 global lakes revealed on average 20% of inflow is lost to evaporation, but 10% of Earth’s lakes show extreme evaporative losses. Stable water isotope monitoring is an effective way to detect comparative climatic and catchment-scale impacts on lake water-balance budgets.

Cardiac hypertrophy resulting from sympathetic nervous system activation triggers the development of heart failure. The transcription factor Y-box binding protein 1 (YB-1) can interact with transcription factors involved in cardiac hypertrophy and may thereby interfere with the hypertrophy growth process. Therefore, the question arises as to whether YB-1 influences cardiomyocyte hypertrophy and might thereby influence the development of heart failure. YB-1 expression is downregulated in human heart biopsies of patients with ischemic cardiomyopathy (n = 8), leading to heart failure. To study the impact of reduced YB-1 in cardiac cells, we performed small interfering RNA (siRNA) experiments in H9C2 cells as well as in adult cardiomyocytes (CMs) of rats. The specificity of YB-1 siRNA was analyzed by a miRNA-like off-target prediction assay identifying potential genes. Testing three high-scoring genes by transfecting cardiac cells with YB-1 siRNA did not result in downregulation of these genes in contrast to YB-1, whose downregulation increased hypertrophic growth. Hypertrophic growth was mediated by PI3K under PE stimulation, as well by downregulation with YB-1 siRNA. On the other hand, overexpression of YB-1 in CMs, caused by infection with an adenovirus encoding YB-1 (AdYB-1), prevented hypertrophic growth under α-adrenergic stimulation with phenylephrine (PE), but not under stimulation with growth differentiation factor 15 (GDF15; n = 10–16). An adenovirus encoding the green fluorescent protein (AdGFP) served as the control. YB-1 overexpression enhanced the mRNA expression of the Gq inhibitor regulator of G-protein signaling 2 (RGS2) under PE stimulation (n = 6), potentially explaining its inhibitory effect on PE-induced hypertrophic growth. This study shows that YB-1 protects cardiomyocytes against PE-induced hypertrophic growth. Like in human end-stage heart failure, YB-1 downregulation may cause the heart to lose its protection against hypertrophic stimuli and progress to heart failure. Therefore, the transcription factor YB-1 is a pivotal signaling molecule, providing perspectives for therapeutic approaches. [ABSTRACT FROM AUTHOR]

Nitrate stable isotopes provide information about nitrate contamination and cycling by microbial processes. The Fischa-Dagnitz (Austria) spring and river system in the agricultural catchment of the Vienna basin shows minor annual variance in nitrate concentrations. We measured nitrate isotopes (δ15N, δ18O) in the source spring and river up to the confluence with the Danube River (2019–2020) with chemical and water isotopes to assess mixing and nitrate transformation processes. The Fischa-Dagnitz spring showed almost stable nitrate concentration (3.3 ± 1.0 mg/l as NO3–-N) year-round but surprisingly variable δ15N, δ18O-NO3– values ranging from +5.5 to +11.1‰ and from +0.5 to +8.1‰, respectively. The higher nitrate isotope values in summer were attributed to release of older denitrified water from the spring whose isotope signal was dampened downstream by mixing. A mixing model suggested denitrified groundwater contributed > 50 % of spring discharge at baseflow conditions. The isotopic composition of NO3– in the gaining streams was partly controlled by nitrification during autumn and winter months and assimilation during the growing season resulting in low and high δ15N-NO3– values, respectively. NO3– isotope variation helped disentangle denitrified groundwater inputs and biochemical cycling processes despite minor variation of NO3– concentration. [ABSTRACT FROM AUTHOR]

The hyporheic zone (HZ) is a hotspot of carbon processing in stream ecosystems as a consequence of the mixing of organic matter and nutrients from ground water and surface waters. However, major knowledge gaps exist regarding the drivers of microbial activity and carbon processing in the HZ among stream ecosystems with different carbon sources and sediment properties. We investigated the impact of algal dissolved organic matter (DOMalgal) and inorganic phosphorus (P) on the degradation of soil DOM (DOMsoil) by hyporheic microorganisms in two laboratory experiments.In our first experiment, we explored the influence of different ratios of DOMalgal to DOMsoil with and without P additions on microbial respiration and DOM composition in laboratory hyporheic microcosms under oxic conditions. Here, we used glass beads colonised by stream microorganisms resembling a pristine stream system. As the addition of DOMalgal increased P concentrations, we added P to adjust the P concentrations to the same level of the pure DOMalgal in a second batch. In our second experiment, we determined the aerobic microbial respiration of HZ‐sediments from 20 streams along a land‐use gradient in Austria incubated with DOMsoil. Again, we performed the experiments with and without P additions to see whether effects on microbial respiration depended on the ambient P concentrations of the streams.Aerobic microbial respiration in the hyporheic microcosms decreased with increasing DOMsoil proportions. When P concentrations were adjusted to the P level of the DOMalgal, aerobic microbial respiration rates were similar between the different DOM mixtures in the microcosms, mainly stimulating the degradation of humic‐like DOM fractions. This highlights the stimulating effects of the P additions on hyporheic microbial respiration and humic‐like DOM degradation in pristine streams. However, P additions caused a significant increase in microbial respiration in only one of 20 natural HZ‐sediments, suggesting that aerobic microbial respiration rates rarely were controlled by P availability in the investigated streams.We conclude that nutrient pulses can, but do not necessarily, stimulate microbial activity and terrestrial carbon degradation in the HZ of streams. Nevertheless, at low ambient nutrient concentrations (i.e., in pristine streams) terrestrial carbon degradation in the HZ can be accelerated when nutrient pulses occur, which has consequences for CO2 outgassing and the organic matter quality in the stream and its export to downstream sections. [ABSTRACT FROM AUTHOR]

The IAEA/WMO session reviewed the present state of knowledge on the interpretation of climate variability by linking isotope hydrology and hydrometeorology, through bringing together meteorologists and hydrologists with and without isotope background. The Isotope Hydrology Section, International Atomic Energy Agency (IAEA), and the Department of Water and Cryosphere, World Meteorological Organization (WMO), conducted a virtual special session 'Better understand past, present and future climate variability by linking water isotopes and conventional hydrometeorology' at the 9th International Conference on Water Resources and Environment Research (ICWRER 2022) organised by the University of Central Florida, Orlando, USA. For climate change assessment, connecting water isotopes and conventional hydrometeorology will move forward the interpretation of climate variability and its impact if the following requirements are fulfilled: Development of novel techniques for automatic collection of atmospheric waters for stable and radioactive isotopes, Preservation of high-quality isotope data for long-term use in databases and the sample archiving, Development of new models to incorporate isotope hydrology into studies investigating climate changes and instabilities. [Extracted from the article]

Microbial heterotrophic activity is a major driver of nutrient and organic matter processing in the hyporheic zone of headwater streams. Additionally, the hyporheic zone might provide refuge for microbes when surface flow ceases during drought events.We investigated chemical (organic and inorganic nutrients) and microbiological parameters (bacterial cell concentration, live–dead ratios, and extracellular enzyme activities) of surface and interstitial pore water in a period of progressive surface‐hyporheic disconnection due to summer drying. The special situation of the chosen study reach, where groundwater mixing is impeded by the bedrock forming a natural channel filled with sediment, allowed as to study the transformation of these parameters along hyporheic flow paths.The chemical composition of the hyporheic pore water reflected the connectivity with the surface water, as expressed in the availability of nitrate and oxygen. Conversely, microbiological parameters in all hyporheic locations were different from the surface waters, suggesting that the microbial activity in the water changes rapidly once the water enters the hyporheic zone. This feature was principally manifested in higher live–dead ratios and lower leucine aminopeptidase (an activity related to nitrogen acquisition) in the hyporheic pore waters.Overall, bacterial cell concentration and extracellular enzyme activities increased along hyporheic flow paths, with a congruent decrease in inorganic nutrients and dissolved organic matter quantity and apparent molecular size.Our findings show two important functions of the hyporheic zone during drought: (1) deeper (−50 cm) water‐saturated layers can act as a refuge for microbial activity; and (2) the hyporheic zone shows high rates of carbon and nitrogen turnover when water residence times are longer during drought. These rates might be even enhanced by an increase in living microbes in the remaining moist locations of the hyporheic zone. [ABSTRACT FROM AUTHOR]

The recent discovery of a new lyotropic liquid crystal phase, the structure and properties of which are analogous to the chiral ferroelectric smectic C-phase (SmC*) in thermotropics, was based on a tailored amphiphile structure in which a tilt-promoting mesogenic core was linked to a chiral diol-headgroup via a hydrophilic ethylene glycol spacer [J. R. Bruckner et al., Angew. Chem., Int. Ed., 2013, 52, 8934–8937]. However, so far there is only one example of this general amphiphile structure known to form the new lyotropic SmC* phase in mixtures with water and with formamide. In an attempt to systematically elucidate the underlying structure–property relations we now report two new amphiphiles leading to lyotropic SmC* phases. These amphiphiles are derived from the parent amphiphile structure by (i) an elongation of the hydrophilic ethylene glycol spacer and (ii) an exchange of the original 2-phenylpyrimidine core by an even more tilt-promoting fluorenone core. Our investigations also reveal that the formation of the lyotropic SmC* phase is highly sensitive to exchanging or enlarging a building block of the primary material. [ABSTRACT FROM AUTHOR]

Citrus stubborn disease is a serious economic problem in California, in Southwestern United States, and in other arid citrus areas of the world. Knowledge of the disease has rapidly increased since 1969 when a mycoplasma-like organism was found by electron microscopy in thin sections of diseased leaves. In 1970, a mycoplasma, now named Spiroplasma citri, was cultured from diseased citrus tissue. Further research has revealed that two leafhoppers (see California Agriculture, November 1973) can transmit the stubborn disease organism. Cultured spiroplasma have been fed or injected into these insects and they, in turn, have transmitted stubborn to healthy citrus seedlings. More recently (see California Agriculture, February 1975), one of the insects, Scaphytopius nitridus, fed on diseased citrus trees was shown to transmit a severe disease to healthy Vinca rosea L., periwinkle plants, in controlled greenhouse experiments. This information prompted our investigating the possibility of natural spread of stubborn into periwinkle plants.

The use of non-ionic LC phases as anisotropic matrices for E/Z-isomerization of azo-guest molecules is often restricted due to limited solubilities and demixing effects. In this study we therefore employed an ionic liquid crystal (ILC) matrix to follow the photo-induced E/Z-isomerization of ionic mesogenic azobenzene guanidinium guests. The latter were prepared from 4-hydroxy-4′-(octyloxy)azobenzene, which was first treated with N-(bromoalkyl)phthalimides to introduce the spacer with varying chain length. Removal of phthalimide and final reaction with a formamidinium salt linked the ionic head group to the photoisomerizable azobenzene unit. Investigation of the mesomorphic behaviour revealed for all azobenzene ILCs smectic A mesophases with high translational order parameters and partial bilayers, as could be stated by layer spacing d. Similar packing behaviour was found for the solid state by X-ray crystal structure analysis. E/Z-isomerization of azobenzene ILCs which were completely miscible with the ionic LC phase of C12MIM-Br as anisotropic host was induced by irradiation with UV light and the reisomerization observed by time-resolved UV-Vis spectroscopy. For comparison, water was used as isotropic host. Z/E-reisomerization activation energies exhibited similar values of 97–100 kJ mol−1 irrespective of spacer lengths and the type of host. The results demonstrate that a proper match of steric requirements of host and guest as well as layer spacings are needed for a decreased activation energy. [ABSTRACT FROM AUTHOR]

Pancreatic endocrine tumors (PET) represent a heterogenous group of neoplasms. Although surgical resection is considered a safe and effective treatment for many PET, therapeutic options for inoperable and progressive PET are limited. The expression of heat-shock protein (HSP) 90 was investigated in 120 clinically and pathomorphologically well-characterized PET from 84 patients using immunohistochemistry. In addition, in 19 snap-frozen PET and in three healthy pancreatic tissues, we performed immunoblot analyses, and in 15 snap-frozen PET and in three healthy pancreatic tissues, we investigated the expression of HSP90 isoforms by means of semiquantitative RT-PCR. Functional tests were conducted using the human pancreas carcinoid cell line BON and the mouse insulinoma cell line &bgr;-TC-3. HSP90 was expressed in 95% of the PET patients. The transcript levels of the HSP90 isoforms HSP90&agr;, HSP90&bgr;, glucose-related protein 94, and TNF receptor-associated protein 1 were significantly increased in PET compared with non-neoplastic pancreatic tissues. The treatment of the cell lines BON and &bgr;-TC-3 with the HSP90 inhibitors 17-allylamino-17-demethoxygeldanamycin and 17-dimethylaminoethylamino-17-demethoxy-geldanamycin resulted in significant, dose-dependent reduction of cell viability, cell cycle arrest, and increased apoptosis. Furthermore, HSP90 inhibition induced the degradation and inactivation of several oncogenetic HSP90 client proteins in a time- and dose-dependent manner. HSP90 inhibitors increased the therapeutic effects of doxorubicin and 5-fluorucacil in BON and &bgr;-TC-3 cells. HSP90 is expressed in the vast majority of PET and its inhibition reveals significant treatment effects in vitro. Thus, HSP90 qualifies as a promising new target. [ABSTRACT FROM AUTHOR]

The Frequency Music Festival attracts more than 200 000 visitors every summer. Most visitors camp in close proximity to the Traisen River, a tributary to the Danube River in Austria. The campers typically stay for four days and make intensive recreational use of the Traisen. To quantify the effects of this distinct human activity on water quality and stream ecosystem functioning, we established a stream sampling campaign and deployed continuously measuring UV-Vis and oxygen probes upstream and downstream of the festival area. With our design, we aimed to evaluate the impact of the Festival on river biogeochemistry, namely dissolved organic matter (DOM) dynamics, nitrate concentrations and stream ecosystem metabolism. Analysis of stream samples revealed an increase in dissolved organic carbon (DOC) concentration by up to 1 mg L-1 which corresponds to a mean increase of 30 % during the festival, as compared to upstream (1.6 mg/L). Fluorescence intensity doubled as a result of the festival, indicating a potential change in DOM sources. Interestingly, the UV-Vis sensors neither detected changes in DOC nor nitrate concentrations during the festival, suggesting that the additional DOM was outside the detection range and was likely different from natural sources. At the contrary, laboratory analysis confirmed that nitrate and total nitrogen concentrations did not change significantly; ecosystem respiration was slightly enhanced. Using parallel factor analysis (PARAFAC) on Excitation-Emission Matrices we were able to assign the increase in DOC to a distinct PARAFAC-component that was neither present in the river before or after the festival, nor upstream the festival area. A laboratory experiment of absorbance and fluorescence of various sources of human associated DOM (sunscreen, beer, human urine, toothpaste, plastics...) indicated that sunscreen was the most probable source. Further, back-of-the-envelope calculations showed that at least 2 tons of sunscreen had to be dissolved into river water to cause the observed gain in DOC concentration during the festival. Overall we conclude that large cultural and recreational events may artificially increase carbon load to river ecosystems. This carbon may modify stream ecosystem functioning, as indicated by the transient increase in ecosystem respiration. As the world's population rises, human induced, man-made synthetic DOM may become more relevant for streams and rivers in the future. [ABSTRACT FROM AUTHOR]

In thermotropic chiral Sm-A* phases, an electric field along the smectic layers breaks the D∞ symmetry of the Sm-A* phase and induces a tilt of the liquid crystal director. This so-called electroclinic effect (ECE) was first reported by Garoff and Meyer in 1977 and attracted substantial scientific and technological interest due to its linear and submicrosecond electro-optic response [S. Garoff and R. B. Meyer, Phys. Rev. A 19, 338 (1979)]. We now report the observation of an ECE in the pretransitional regime from a lyotropic chiral lamellar L*α phase into a lyo-Sm-C* phase, the lyotropic analog to the thermotropic Sm-C* phase which was recently discovered by Bruckner et al. [Angew. Chem. Int. Ed. 52, 8934 (2013)]. We further show that the observed ECE has all signatures of its thermotropic counterpart, namely (i) the effect is chiral in nature and vanishes in the racemic Lα phase, (ii) the effect is essentially linear in the sign and magnitude of the electric field, and (iii) the magnitude of the effect diverges hyperbolically as the temperature approaches the critical temperature of the second order tilting transition. Specific deviations between the ECEs in chiral lamellar and chiral smectic phases are related to the internal field screening effect of electric double layers formed by inevitable ionic impurities in lyotropic phases. [ABSTRACT FROM AUTHOR]

Hydrology is the main driver of dissolved organic matter (DOM) dynamics in intermittent rivers and ephemeral streams. However, it is still unclear how the timing and the spatial variation in flow connectivity affect the dynamics of DOM and inorganic solutes. This study focuses on the impact of flow cessation on the temporal and spatial heterogeneity of DOM quantity and quality along an intermittent stream. We monitored a headwater intermittent stream at high spatial and temporal frequencies during a summer drying episode and analysed dissolved organic carbon (DOC) and its spectroscopic properties, inorganic solutes and dissolved CO 2. The drying period determined the disruption of the fluvial continuum with a recession of stream continuum at a rate of ~60 m/d and the gradual formation of a patched system of isolated pools of different sizes. Our results showed that the period of time that had elapsed since isolated pool formation (CI-days) was an essential factor for understanding how drying shaped the biogeochemistry of the fluvial system. Overall, drying caused a high DOC concentration and an increase in the humic-like fluorescence signal. Additionally, solutes showed contrasting responses to hydrological disconnection. Electrical conductivity, for instance, is a clear "sentinel" of the fragmentation process because it starts to increase before the hydrological disruption occurs. In contrast, DOC, most spectroscopic DOM descriptors and CO 2 showed delayed responses of approximately 5–21 days after the formation of isolated pools. Furthermore, the spatial location and volume of each isolated pool seemed to exert a significant impact on most variables. In contrast, the temperature did not follow a clear pattern. These findings indicate that the fragmentation of longitudinal hydrological connectivity does not induce a single biogeochemical response but rather stimulates a set of solute-specific responses that generates a complex biogeochemical mosaic in a single fluvial unit. Unlabelled Image • Timing of stream fragmentation is a key predictor of biogeochemical variability. • Most of DOM parameters showed abrupt and delayed responses after fragmentation. • Some inorganic solutes showed an anticipated response to fragmentation. • Spatial location and pool volume were relevant in explaining some descriptors. [ABSTRACT FROM AUTHOR]