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SUMMARY: Dinoflagellates have a rich history of characterization of their membrane‐reinforcing sterols because of a structural diversity and chemotaxonomic utility uncommon to other classes of algae. The Kareniaceae are no exception in that they produce sterols, often containing a Δ8(14) nuclear unsaturation, which are rare in most other dinoflagellate groups. A continuing goal of our laboratory is to examine the sterols of previously uncharacterized dinoflagellates to assess their sterol‐based chemotaxonomy compared to other members of the Dinophyceae. Asterodinium gracile, a member of the Kareniaceae, has not been commercially available for study until recently. To this end, our objective was to characterize the sterols of A. gracile to determine whether they match the 4α‐methyl‐substituted, Δ8(14)‐nuclear‐unsaturated sterols, such as (24R)‐4α‐methyl‐5α‐ergosta‐8(14),22‐dien‐3β‐ol (gymnodinosterol; C29:2) and 27‐nor‐(24R)‐4α‐methyl‐5α‐ergosta‐8(14),22‐dien‐3β‐ol (brevesterol; C28:2), of most species within the canonical genera Karenia, Karlodinium and Takayama, or instead the 4‐desmethyl sterols, such as 27‐nor‐(24R)‐23‐methyl‐ergosta‐8(14),22‐dien‐3β‐ol (C28:2), of its chemotaxonomically atypical, yet closest phylogenetic relative, Karenia papilionacea. We have observed A. gracile to produce two 4α‐methyl‐substituted sterols with the suggested structures of 4α‐methyl‐5α‐ergosta‐8(14)‐en‐3β‐ol (C29:1) and 4α‐methyl‐5α‐ergosta‐8(14),24(28)‐dien‐3β‐ol (amphisterol, C29:2), as major sterols amongst five other minor sterols, which included the common dinoflagellate sterol cholest‐5‐en‐3β‐ol (cholesterol, C27:1), but did not include gymnodinosterol or brevesterol (as in most canonical Kareniaceae) or 27‐nor‐(24R)‐23‐methyl‐ergosta‐8(14),22‐dien‐3β‐ol (as found in K. papilionacea). Detection of amphisterol and 4α‐methyl‐5α‐ergosta‐8(14)‐en‐3β‐ol is notable because they are sterols associated with some species of Amphidinium, such as Amphidinium carterae, and, to our knowledge, have not been observed in a member of the Kareniaceae before. Discovery of these major sterols in A. gracile expands our knowledge of the range of sterols produced by the Kareniaceae and indicates a shared chemotaxonomy with some species of Amphidinium. [ABSTRACT FROM AUTHOR]

Small, low-power, and inexpensive marine depth sensors are of interest for a myriad of applications from maritime security to environmental monitoring. Recently, laser-induced graphene (LIG) piezoresistive pressure sensors have been proposed given their rapid fabrication and large dynamic range. In this work, the practicality of LIG integration into fieldable deep ocean (1 km) depth sensors in bulk is explored. Initially, a design of experiments (DOEs) approach evaluated laser engraver fabrication parameters such as line length, line width, laser speed, and laser power on resultant resistances of LIG traces. Next, uniaxial compression and thermal testing at relevant ocean pressures up to 10.3 MPa and temperatures between 0 and 25 °C evaluated the piezoresistive response of replicate sensors and determined the individual characterization of each, which is necessary. Additionally, bare LIG sensors showed larger resistance changes with temperature (ΔR ≈ 30 kΩ) than pressure (ΔR ≈ 1–15 kΩ), indicating that conformal coatings are required to both thermally insulate and electrically isolate traces from surrounding seawater. Sensors encapsulated with two dip-coated layers of 5 wt% polydimethylsiloxane (PDMS) silicone and submerged in water baths from 0 to 25 °C showed significant thermal dampening (ΔR ≈ 0.3 kΩ), indicating a path forward for the continued development of LIG/PDMS composite structures. This work presents both the promises and limitations of LIG piezoresistive depth sensors and recommends further research to validate this platform for global deployment. [ABSTRACT FROM AUTHOR]

SUMMARY: Asterodinium gracile is a morphologically distinct, star‐shaped member of the Kareniaceae with, like canonical Kareniaceae, a tertiary plastid of haptophyte origin. However, A. gracile's complement of carotenoid photosynthetic pigments has been shown to be chemotaxonomically atypical in that it possesses much less fucoxanthin when compared to that of other, canonical Kareniaceae in the genera Karenia, Karlodinium, and Takayama, also with a tertiary plastid of haptophyte origin. To date, Karenia mikimotoi, Karenia papilionacea, and Karenia selliformis are the only canonical Kareniaceae that have been shown to have a chemotaxonomically atypical carotenoid pigment composition in that they possess a gyroxanthin diester‐like carotenoid not observed in other species of Karenia, Karlodinium, or Takayama (recognizing that Karenia, in general, produces fucoxanthin derivatives not observed in Karlodinium or Takayama). As a photosynthetic organism, K. mikimotoi has been shown to resemble Karenia brevis such that both species possess the chloroplast‐associated galactolipids mono‐ and digalactosyldiacylglycerol (MGDG and DGDG, respectively) enriched with octadecapentaenoic acid (18:5(n‐3)) in the sn‐1 position, and hexadecenoic acid (16:0) and tetradecanoic acid (14:0) at the sn‐2 position. However, K. mikimotoi is chemotaxonomically atypical beyond its carotenoid composition in that it possesses MGDG and DGDG with hexadecatetraenoic acid (16:4(n‐3)), which has not been observed in any other members of the Kareniaceae, in the sn‐2 position as major galactolipids. The goal of this study was to characterize the galactolipids of A. gracile with the hypothesis that they would also be atypical when compared to other canonical Kareniaceae because of A. gracile's atypical carotenoid pigment composition. To this end, we report that like K. brevis and K. mikimotoi, A. gracile produces MGDG and DGDG enriched in 18:5(n‐3) at the sn‐1 position and C14 fatty acids, such as 14:0, at the sn‐2 position, and like K. mikimotoi, it produces 18:5(n‐3)/16:4(n‐3) MGDG, yet here as its most abundant galactolipid. [ABSTRACT FROM AUTHOR]

Various pathophysiological situations of negative energy balance involve the intense depletion of the body's energy reserves. White adipose tissue is a central place to store energy and a major endocrine organ. As a model of choice to better understand how the white adipose tissue dynamically responds to changes in substrate availability, we used the prolonged fasting paradigm, which is characterized by successive periods of stimulated (phase 2) and then reduced (phase 3) lipid mobilization/utilization. Using omics analyses, we report a regulatory transcriptional program in rat epididymal (EPI) adipose tissue favoring lipolysis during phase 2 and repressing it during phase 3. Changes in gene expression levels of lipases, lipid droplet-associated factors, and the proteins involved in cAMP-dependent and cAMP-independent regulation of lipolysis are highlighted. The mRNA and circulating levels of adipose-secreted factors were consistent with the repression of insulin signaling during prolonged fasting. Other molecular responses are discussed, including the regulation of leptin and adiponectin levels, the specific changes reflecting an increased fibrinolysis and a possible protein catabolism-related energy saving mechanism in late fasting. Finally, some differences between internal and subcutaneous (SC) adipose tissues are also reported. These data provide a comprehensive molecular basis of adipose tissue responses when facing a major energetic challenge. [ABSTRACT FROM AUTHOR]

We report on arrayed germanium-on-silicon waveguide photodetectors for high-power analog applications utilizing the AIM Photonics silicon foundry. Photodetector arrays with two, four, and eight elements reach output powers of −0.4 dBm, 10 dBm, and 14.3 dBm at 18 GHz, 12 GHz, and 5 GHz, respectively. The 4-photodiode array has an output third order intercept point (OIP3) above 20 dBm up to 12 GHz and shows a 5-dB improvement over a single photodiode. An integrated 20 GHz receiver based on a pair of balanced photodiodes and a Mach–Zehnder delay line interferometer is successfully demonstrated in an optical phase-modulated link. [ABSTRACT FROM AUTHOR]

Previous studies have shown that polyethylene glycol (PEG)-induced osmotic stress (OS) reduces cell-wall (CW) porosity and limits aluminium (Al) uptake by root tips of common bean (Phaseolus vulgaris L.). A subsequent transcriptomic study suggested that genes related to CW processes are involved in adjustment to OS. In this study, a proteomic and phosphoproteomic approach was applied to identify OS-induced protein regulation to further improve our understanding of how OS affects Al accumulation. Analysis of total soluble proteins in root tips indicated that, in total, 22 proteins were differentially regulated by OS; these proteins were functionally categorized. Seventy-seven per- cent of the total expressed proteins were involved in metabolic pathways, particularly of carbohydrate and amino acid metabolism. An analysis of the apoplastic proteome revealed that OS reduced the level of five proteins and increased that of seven proteins. Investigation of the total soluble phosphoproteome suggested that dehydrin responded to OS with an enhanced phosphorylation state without a change in abundance. A cellular immunolocalization analysis indicated that dehydrin was localized mainly in the CW. This suggests that dehydrin may play a major protective role in the OS-induced physical breakdown of the CW structure and thus maintenance of the reversibility of CW extensibility during recovery from OS. The proteomic and phosphoproteomic analyses provided novel insights into the complex mechanisms of OS-induced reduction of Al accumulation in the root tips of common bean and highlight a key role for modification of CW structure. [ABSTRACT FROM AUTHOR]

Sterols are vital for cellular functions and eukaryotic development because of their essential role as membrane constituents. Sterol biosynthetic intermediates (SBIs) represent a potential reservoir of signaling molecules in mammals and fungi, but little is known about their functions in plants. SBIs are derived from the sterol C4-demethylation enzyme complex that is tethered to the membrane by Ergosterol biosynthetic protein28 (ERG28). Here, using nonlethal loss-of-function strategies focused on Arabidopsis thaliana ERG28 , we found that the previously undetected SBI 4-carboxy-4-methyl-24-methylenecycloartanol (CMMC) inhibits polar auxin transport (PAT), a key mechanism by which the phytohormone auxin regulates several aspects of plant growth, including development and responses to environmental factors. The induced accumulation of CMMC in Arabidopsis erg28 plants was associated with diagnostic hallmarks of altered PAT , including the differentiation of pin-like inflorescence, loss of apical dominance, leaf fusion, and reduced root growth. PAT inhibition by CMMC occurs in a brassinosteroid-independent manner. The data presented show that ERG28 is required for PAT in plants. Furthermore, it is accumulation of an atypical SBI that may act to negatively regulate PAT in plants. Hence, the sterol pathway offers further prospects for mining new target molecules that could regulate plant development. [ABSTRACT FROM AUTHOR]

The protein ReP1-NCXSQ was isolated from the cytosol of squid nerves and has been shown to be required for MgATP stimulation of the squid nerve Na+/Ca2+ exchanger NCXSQ1. In order to determine its mode of action and the corresponding biologically active ligand, sequence analysis, crystal structures and mass-spectrometric studies of this protein and its Tyr128Phe mutant are reported. Sequence analysis suggests that it belongs to the CRABP family in the FABP superfamily. The X-ray structure at 1.28 Å resolution shows the FABP β-barrel fold, with a fatty acid inside the barrel that makes a relatively short hydrogen bond to Tyr128 and shows a double bond between C9 and C10 but that is disordered beyond C12. Mass-spectrometric studies identified this fatty acid as palmitoleic acid, confirming the double bond between C9 and C10 and establishing a length of 16 C atoms in the aliphatic chain. This acid was caught inside during the culture in Escherichia coli and therefore is not necessarily linked to the biological activity. The Tyr128Phe mutant was unable to activate the Na+/Ca2+ exchanger and the corresponding crystal structure showed that without the hydrogen bond to Tyr128 the palmitoleic acid inside the barrel becomes disordered. Native mass-spectrometric analysis confirmed a lower occupancy of the fatty acid in the Tyr128Phe mutant. The correlation between (i) the lack of activity of the Tyr128Phe mutant, (ii) the lower occupancy/disorder of the bound palmitoleic acid and (iii) the mass-spectrometric studies of ReP1-NCXSQ suggests that the transport of a fatty acid is involved in regulation of the NCXSQ1 exchanger, providing a novel insight into the mechanism of its regulation. In order to identify the biologically active ligand, additional high-resolution mass-spectrometric studies of the ligands bound to ReP1-NCXSQ were performed after incubation with squid nerve vesicles both with and without MgATP. These studies clearly identified palmitic acid as the fatty acid involved in regulation of the Na+/Ca2+ exchanger from squid nerve. [ABSTRACT FROM AUTHOR]

The digestive vacuole plays an important role in the pathophysiology of the human malaria parasite Plasmodium falciparum. It is a terminal degradation organelle involved in the proteolysis of the host erythrocyte's haemoglobin; it is the site of action of several antimalarial drugs and its membrane harbours transporters implicated in drug resistance. How the digestive vacuole recruits residential proteins is largely unknown. Here, we have investigated the mechanism underpinning trafficking of the chloroquine resistance transporter, PfCRT, to the digestive vacuolar membrane. Nested deletion analysis and site-directed mutagenesis identified threonine 416 as a functional residue for sorting PfCRT to its site of residence. Mass spectroscopy demonstrated that threonine 416 can be phosphorylated. Further phosphorylation was detected at serine 411. Our data establish PfCRT as a phosphoprotein and suggest that phosphorylation of threonine 416 is a possible deciding signal for the sorting of PfCRT to the digestive vacuolar membrane. [ABSTRACT FROM AUTHOR]

A correction is published to Table 2 in the article by Cousido-Siah et al. [(2012), Acta Cryst. D68, 10981107]. [ABSTRACT FROM AUTHOR]