Icescape-scale metabolomics reveals cyanobacterial and topographic control of the core metabolism of the cryoconite ecosystem of an Arctic ice cap

Glaciers host ecosystems comprised of biodiverse and active microbiota. Among glacial ecosystems, less is known about the ecology of ice caps since most studies focus on valley glaciers or ice sheet margins. Previously we detailed the microbiota of one such high Arctic ice cap, focusing on cryoconite as a microbe-mineral aggregate formed by cyanobacteria. Here, we employ metabolomics at the scale of an entire ice cap to reveal the major metabolic pathways prevailing in the cryoconite of Foxfonna, central Svalbard. We reveal how geophysical and biotic processes influence the metabolomes of its resident cryoconite microbiota. We observed differences in amino acid, fatty acid, and nucleotide synthesis across the cap reflecting the influence of ice topography and the cyanobacteria within cryoconite. Ice topography influences central carbohydrate metabolism and nitrogen assimilation, whereas bacterial community structure governs lipid, nucleotide, and carotenoid biosynthesis processes. The prominence of polyamine metabolism and nitrogen assimilation highlights the importance of recycling nitrogenous nutrients. To our knowledge, this study represents the first application of metabolomics across an entire ice mass, demonstrating its utility as a tool for revealing the fundamental metabolic processes essential for sustaining life in supraglacial ecosystems experiencing profound change due to Arctic climate change-driven mass loss.     

Evaluation of thermal environment by real time monitoring SET

1. 1. A system, combining a portable data logger and a personal computer with a GP-IB interface, was developed both to measure environmental variables and also to predict human physiological responses to one's thermal environment.

2. 2. An environmental index: Standard Effective Temperature SET^*, can also be computed with the personal computer and displayed on the CRT for the real time monitoring of the thermal environment and comfort sensation.

Anti-Herpes Simplex Virus substances produced by the marine green alga, Dunaliella primolecta

Among 106 microalgae tested, the cytopathic effect (CPE) upon Vero cells of herpes simplex virus, Type 1 (HSV-1) was inhibited by four methanol extracts of Dunaliella bioculata C-523, D. primolecta C-525, Lyngbya sp. M-9 and Lyngbya aerugineo-coerulea M-12. The green alga, D. primolecta, had the highest anti HSV-1 activity, since 10 μg mL-1 of extract from this alga completely inhibited the CPE. This activity was similar to that of acyclovir at the same concentration. We compared anti-viral activities against adeno virus, herpes simplex virus-2 (HSV-2), Japanese Encephalitis and Polio viruses. Only the CPE of HSV-2 was inhibited. Thus, the factor was specific against HSV. The antiviral activity was apparently excited during HSV adsorption and invasion of the cells. We optimized the conditions for anti HSV-1 activity by prolonging the exposure of HSV-1 to the extract. After 2 h, the CPE of even a high titer of HSV-1 (106 TCID50/0.1 mL) was completely inactivated. By use of various chromatographic techniques, three green substances having anti-HSV activity were purified from the algal mass of D. primolecta, and 5 μg mL-1 of this purified substances completely inhibited the CPE. From the analysis of NMR and MS, the chemical structures of the active substances were identified as pheophorbide-like compounds. This revised version was published online in June 2006 with corrections to the Cover Date.     

Changes in the cellular localization of cytosolic glutamine synthetase protein in vascular bundles of rice leaves at various stages of development

Cellular localization of cytosolic glutamine synthetase (GS1; EC 6.3.1.2) in vascular bundles of leaf blades of rice (Oryza sativa L.), at the stage at which leaf blades 6 (the lowest position) to 10 were fully expanded, was investigated immunocytologically with an affinity-purified anti-GS1 immunoglobulin G. Strong signals for GS1 protein were detected in companion cells of large vascular bundles when blades 6–8 were tested. Signals for GS1 were also observed in vascular-parenchyma cells of both large and small vascular bundles. The results further support our hypothesis that GS1 is important for the export of leaf nitrogen from senescing leaves. The signals in companion cells were less striking in the younger green leaves and were hardly detected in the non-green portion of the 11th blade. In the non-green blades, strong signals for GS1 protein were detected in sclerenchyma and xylemparenchyma cells. When total GS extracts prepared from the 6th,10th, and the non-green 11th blades were subjected to anion-exchange chromatography, the activity of GS1 was clearly separated from that of chloroplastic GS, indicating that GS1 proteins detected in the vascular tissues were able to synthesize glutamine. The function of GS1 detected in the developing leaves is discussed.Abbreviations Fd-GOGAT ferredoxin-dependent glutamate synthase - GS1 cytosolic glutamine synthetase - GS2 plastidic glutamine synthetase - IgG immunoglobulin G     

Regulation of pyridoxal-5′-phosphate level by biogenic amines in mouse brain

We investigated the relationship between the concentration of pyridoxal-5′-phosphate (PLP) and biogenic amine in mouse brain. The production of PLP from pyridoxal (PL) by pyridoxal kinase (PLK) was inhibited by the addition of dopamine (DA), norepinephrine (NE) and 5-hydroxytryptamine (5-HT), but not by that of epinephrine and N-acetyl-serotonin. DA and NE were combined with PLP by a non-enzymatic reaction, whereas 5-HT was bound only slightly with PLP. The conjugated product of PLP with DA was also detected by HPLC analysis when PLK activity was assayed using PL as a substrate in the presence of DA. In an in vivo investigation, the depletion of DA and 5-HT in mouse brain after an intraperitoneal injection of 5 mg/kg reserpine, led to slight elevation of the PLP level to 120% of the control level. By contrast, the increase in DA in the brain caused by intraperitoneal administration of 150 mg/kg L-DOPA caused the PLP concentration to decrease to 70% of the control level. However, no change in PLK activity in the brain was observed when the mice were treated with either reserpine or L-DOPA. These results suggested that the level of PLP in mouse brain was partly regulated by the concentration of biogenic amines, such as DA, NE and 5-HT, without apparent induction of PLK.     

ATP-dependent transport for glucuronides in canalicular plasma membrane vesicles

Using rat liver canalicular plasma membrane vesicles, it has been verified that the transport of p-nitrophenyl glucuronide (NPG) across membranes is an ATP-dependent process; the apparent Km for NPG was 20 microM. S-(2,4-dinitrophenyl)-glutathione (DNP-SG) inhibited NPG uptake dose-dependently, and NPG or testosterone glucuronide did ATP-dependent DNP-SG uptake similarly. These results suggest that transport of glucuronide is mediated by an ATP-dependent glutathione S-conjugate carrier.     

A new monoclonal antibody directed to sialyl alpha 2-3lactoneotetraosylceramide and its application for detection of human gastrointestinal neoplasms

A new monoclonal antibody (NS24) directed to the N-acetylneuraminyl alpha 2-3Gal beta 1-4GlcNAc residue in type II sugar chain of N-acetylneuraminyllactoneotetraosylceramide [sialylparagloboside, IV3(NeuAc)nLc4Cer] was prepared by hybridoma technique. Liposomes composed of dipalmitoylphosphatidylcholine, cholesterol, IV3(NeuAc)nLc4Cer, and lipopolysaccharides from Salmonella minnesota R595 were used for immunization with IV3(NeuAc)nLc4Cer isolated from human erythrocytes. This method allowed the fusion of spleen cells of immunized mouse with myeloma cells only three days after immunization. NS24 reacted specifically to both naturally occurring and chemically synthesized IV3-(NeuAc)nLc4Cer, whereas it has no reactivity to structurally related gangliosides, such as IV6(NeuAc)nLc4Cer, N-glycolylneuraminyl alpha 2-3lactoneotetraosylceramide [IV3(NeuGc)-nLc4Cer], i-active ganglioside [VI3(NeuAc)nLc6Cer], I-active ganglioside [VIII3(NeuAc)-VI3(NeuAc)IV6kladoLc8Cer], GM4(NeuAc), GM3(NeuAc), GM3(NeuGc), GM1b(NeuAc), GD3-(NeuAc), other ganglio-series gangliosides, sulfatide, and paragloboside (nLc4Cer). Synthetic N-acetylneuraminyl alpha 2-3lactotetraosylceramide [IV3(NeuAc)Lc4Cer] and its asialo-derivative (Lc4Cer) carrying type I sugar chain also showed no reaction with NS24. One to 100 pmol of IV3(NeuAc)nLc4Cer was detected dose-dependently by a thin-layer chromatography/enzyme immunostaining procedure. Human gastric carcinomas showed positive reactions with NS24 immunochemically and histochemically. NS24 reacted preferentially with poorly differentiated adenocarcinomas rather than well differentiated ones.     

Nonclassical 3 beta-hydroxysteroid dehydrogenase deficiency in young girls with hirsutism and premature pubarche

Two young girls with hirsutism and premature pubarche showed nonclassical 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency. Post-ACTH increased serum delta 5-17-hydroxypregnenolone and increased ratio of delta 5-17-hydroxypregnenolone/17-hydroxyprogesterone are the most sensitive indicators of nonclassical 3 beta-HSD deficiency. Nonclassical 3 beta-HSD deficiency may not be uncommon, but most cases may have gone unrecognized. Routine assay of delta 5-17-hydroxypregnenolone should be made generally available.