Distribution and metabolism of adrenocorticotropin in the rat.

The time course of plasma bioactive adrenocorticotropin (ACTH) concentrations measured following two rapid injections of the hormone at doses of 7.5 and 22.5 mU/100 g, iv, and one infusion over a period of 80 min at a rate of 1.3 mU/min per 100 g, to male Sprague-Dawley rats whose endogenous release of ACTH had been blocked, leads to the conclusion that the hormone is distributed in two compartments. Indeed, the rapid fall of plasma ACTH concentrations in the early minutes following either the injections or the stop of the infusion is followed by a much slower phase. There is no significant difference between the measurements and the two-compartment model outputs. The model represents, on the average, the mean values of the measurements plus or minus 1 standard error for the single injections and plus or minus 1.2 standard error for the infusion.     

A new fluorometric method for determination of picomoles of inorganic phosphorus. Application to the renal tubular fluid

A new method for the determination of inorganic phosphorus (Pi) in 4 nl of renal tubular fluid is described. Phosphate is converted to hexadimolybdatophosphate, which is reacted with thiamine to produce a highly fluorescent thiochrome. The reaction is stable and reproducible. Problems of interference are minimal. Microdeterminations of Pi in the proximal tubules and glomerular filtrates of the rat yielded results similar to those published in the literature.     

Adrenocortical responses to ACTH (author's transl)]

To characterize by a mathematical model the dynamics of adrenocortical responses to ACTH, the concentration of plasma corticosterone was measured following a series of injections and perfusions of ACTH to dexamethasone-treated male rats. A similar slope was observed during the rise of plasma corticosterone following graded pulse inputs, and the steady-state corticosterone secretion rate was shown to increase proportionally to the perfusion rate of ACTH up to saturation corresponding to maximal secretion. The data will be used, concurrently with our model of the dynamics of plasma cortiscosterone, for the identification of a mathematical model of the adrenocortical response to ACTH.     

Cyclin D1 and cyclin D3 show divergent responses to distinct mitogenic stimulation

D‐type cyclins predominantly regulate progression through the cell cycle by their interactions with cyclin‐dependent kinases (cdks). Here, we show that stimulating mitogenesis of Swiss 3T3 cells with phorbol esters or forskolin can induce divergent responses in the expression levels, localization and activation state of cyclin D1 and cyclin D3. Phorbol ester‐mediated protein kinase C stimulation induces S phase entry which is dependent on MAPK activation and increases the levels and activation of cyclin D1, whereas forskolin‐mediated cAMP‐dependent protein kinase A stimulation induces mitogenesis that is independent of MAPK, but dependent upon mTor and specifically increases the level and activation of cyclin D3. These findings uncover additional levels of complexity in the regulation of the cell cycle at the level of the D‐type cyclins and thus may have important therapeutic implications in cancers where specific D‐cyclins are overexpressed. J. Cell. Physiol. 225: 638–645, 2010. © 2010 Wiley‐Liss, Inc.     

Exogene Entstehung der Antheridien vonAnthoceros

Ohne Zusammenfassung     

The effect of microbial mycolytic agents on Trichophyton rubrum

Chitinolytic microorganisms isolated from forest soil and from healthy gypsy moth larvae (Porthetria dispar (L.) were screened for their ability to lyse Trichophyton rubrum mycelia. A few of these isolates were mycolytic on both autoclaved and on actively growing, intact, T. rubrum mycelia. Supernatants from these isolates, utilizing live T. rubrum as the sole carbon source, showed the same mycolytic ability. Assays of the supernatants for enzymatic activity revealed exocellular, stable enzymes that releases reducing substances including N-acetylglucosamine from the mycelia.     

Rap1 Can Bypass the FAK-Src-Paxillin Cascade to Induce Cell Spreading and Focal Adhesion Formation

We developed new image analysis tools to analyse quantitatively the extracellular-matrix-dependent cell spreading process imaged by live-cell epifluorescence microscopy. Using these tools, we investigated cell spreading induced by activation of the small GTPase, Rap1. After replating and initial adhesion, unstimulated cells exhibited extensive protrusion and retraction as their spread area increased, and displayed an angular shape that was remodelled over time. In contrast, activation of endogenous Rap1, via 007-mediated stimulation of Epac1, induced protrusion along the entire cell periphery, resulting in a rounder spread surface, an accelerated spreading rate and an increased spread area compared to control cells. Whereas basal, anisotropic, spreading was completely dependent on Src activity, Rap1-induced spreading was refractory to Src inhibition. Under Src inhibited conditions, the characteristic Src-induced tyrosine phosphorylations of FAK and paxillin did not occur, but Rap1 could induce the formation of actomyosin-connected adhesions, which contained vinculin at levels comparable to that found in unperturbed focal adhesions. From these results, we conclude that Rap1 can induce cell adhesion and stimulate an accelerated rate of cell spreading through mechanisms that bypass the canonical FAK-Src-Paxillin signalling cascade.     

Uncovering Atomic‐Scale Stability and Reactivity in Engineered Zinc Oxide Electrocatalysts for Controllable Syngas Production

In this study, scalable, flame spray synthesis is utilized to develop defective ZnO nanomaterials for the concurrent generation of H₂ and CO during electrochemical CO₂ reduction reactions (CO₂RR). The designed ZnO achieves an H₂/CO ratio of ≈1 with a large current density (j) of 40 mA cm^?2 during long‐term continuous reaction at a cell voltage of 2.6 V. Through in situ atomic pair distribution function analysis, the remarkable stability of these ZnO structures is explored, addressing the knowledge gap in understanding the dynamics of oxide catalysts during CO₂RR. Through optimization of synthesis conditions, ZnO facets are modulated which are shown to affect reaction selectivity, in agreement with theoretical calculations. These findings and insights on synthetic manipulation of active sites in defective metal‐oxides can be used as guidelines to develop active catalysts for syngas production for renewable power‐to‐X to generate a range of fuels and chemicals.     

Forecasting intensifying disturbance effects on coral reefs

Anticipating future changes of an ecosystem's dynamics requires knowledge of how its key communities respond to current environmental regimes. The Great Barrier Reef (GBR) is under threat, with rapid changes of its reef‐building hard coral (HC) community structure already evident across broad spatial scales. While several underlying relationships between HC and multiple disturbances have been documented, responses of other benthic communities to disturbances are not well understood. Here we used statistical modelling to explore the effects of broad‐scale climate‐related disturbances on benthic communities to predict their structure under scenarios of increasing disturbance frequency. We parameterized a multivariate model using the composition of benthic communities estimated by 145,000 observations from the northern GBR between 2012 and 2017. During this time, surveyed reefs were variously impacted by two tropical cyclones and two heat stress events that resulted in extensive HC mortality. This unprecedented sequence of disturbances was used to estimate the effects of discrete versus interacting disturbances on the compositional structure of HC, soft corals (SC) and algae. Discrete disturbances increased the prevalence of algae relative to HC while the interaction between cyclones and heat stress was the main driver of the increase in SC relative to algae and HC. Predictions from disturbance scenarios included relative increases in algae versus SC that varied by the frequency and types of disturbance interactions. However, high uncertainty of compositional changes in the presence of several disturbances shows that responses of algae and SC to the decline in HC needs further research. Better understanding of the effects of multiple disturbances on benthic communities as a whole is essential for predicting the future status of coral reefs and managing them in the light of new environmental regimes. The approach we develop here opens new opportunities for reaching this goal.     

Sediment cooling triggers germination and sulfate reduction by heat-resistant thermophilic spore-forming bacteria

Thermophilic endospores are widespread in cold marine sediments where the temperature is too low to support growth and activity of thermophiles in situ. These endospores are likely expelled from warm subsurface environments and subsequently dispersed by ocean currents. The endospore upper temperature limit for survival is 140°C, which can be tolerated in repeated short exposures, potentially enabling transit through hot crustal fluids. Longer-term thermal tolerance of endospores, and how long they could persist in an environment hotter than their maximum growth temperature, is less understood. To test whether thermophilic endospores can survive prolonged exposure to high temperatures, sediments were incubated at 80–90°C for 6, 12 or 463 days. Sediments were then cooled by 10–40°C, mimicking the cooling in subsurface oil reservoirs subjected to seawater injection. Cooling the sediments induced sulfate reduction, coinciding with an enrichment of endospore-forming Clostridia. Different Desulfofundulus, Desulfohalotomaculum, Desulfallas, Desulfotomaculum and Desulfofarcimen demonstrated different thermal tolerances, with some Desulfofundulus strains surviving for >1 year at 80°C. In an oil reservoir context, heat-resistant endospore-forming sulfate-reducing bacteria have a survival advantage if they are introduced to, or are resident in, an oil reservoir normally too hot for germination and growth, explaining observations of reservoir souring following cold seawater injection.