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Stramenopile algae contribute significantly to global primary productivity, and one class, Eustigmatophyceae, is increasingly studied for applications in high-value lipid production. Yet much about their basic biology remains unknown, including the nature of an enigmatic, pigmented globule found in vegetative cells. Here, we present an in-depth examination of this "red body," focusing on Nannochloropsis oceanica. During the cell cycle, the red body forms adjacent to the plastid, but unexpectedly it is secreted and released with the autosporangial wall following cell division. Shed red bodies contain antioxidant ketocarotenoids, and overexpression of a beta-carotene ketolase results in enlarged red bodies. Infrared spectroscopy indicates long-chain, aliphatic lipids in shed red bodies and cell walls, and UHPLC-HRMS detects a C32 alkyl diol, a potential precursor of algaenan, a recalcitrant cell wall polymer. We propose that the red body transports algaenan precursors from plastid to apoplast to be incorporated into daughter cell walls. The red body is a characteristic cellular structure of unknown function in eustigmatophyte algae. Using imaging and spectroscopy, the authors investigate the red body and propose a role in delivery of algaenan precursors for cell wall formation. [ABSTRACT FROM AUTHOR]

Archaea are usually minor components of a microbial community and dominated by a large and diverse bacterial population. In contrast, the SM1 Euryarchaeon dominates a sulfidic aquifer by forming subsurface biofilms that contain a very minor bacterial fraction (5%). These unique biofilms are delivered in high biomass to the spring outflow that provides an outstanding window to the subsurface. Despite previous attempts to understand its natural role, the metabolic capacities of the SM1 Euryarchaeon remain mysterious to date. In this study, we focused on the minor bacterial fraction in order to obtain insights into the ecological function of the biofilm. We link phylogenetic diversity information with the spatial distribution of chemical and metabolic compounds by combining three different state-of-the-art methods: PhyloChip G3 DNA microarray technology, fluorescence in situ hybridization (FISH) and synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy. The results of PhyloChip and FISH technologies provide evidence for selective enrichment of sulfate-reducing bacteria, which was confirmed by the detection of bacterial dissimilatory sulfite reductase subunit B (dsrB) genes via quantitative PCR and sequence-based analyses. We further established a differentiation of archaeal and bacterial cells by SR-FTIR based on typical lipid and carbohydrate signatures, which demonstrated a co-localization of organic sulfate, carbonated mineral and bacterial signatures in the biofilm. All these results strongly indicate an involvement of the SM1 euryarchaeal biofilm in the global cycles of sulfur and carbon and support the hypothesis that sulfidic springs are important habitats for Earth's energy cycles. Moreover, these investigations of a bacterial minority in an Archaea-dominated environment are a remarkable example of the great power of combining highly sensitive microarrays with label-free infrared imaging. [ABSTRACT FROM AUTHOR]

The Deepwater Horizon oil spill in the Gulf of Mexico resulted in a deep-sea hydrocarbon plume that caused a shift in the indigenous microbial community composition with unknown ecological consequences. Early in the spill history, a bloom of uncultured, thus uncharacterized, members of the Oceanospirillales was previously detected, but their role in oil disposition was unknown. Here our aim was to determine the functional role of the Oceanospirillales and other active members of the indigenous microbial community using deep sequencing of community DNA and RNA, as well as single-cell genomics. Shotgun metagenomic and metatranscriptomic sequencing revealed that genes for motility, chemotaxis and aliphatic hydrocarbon degradation were significantly enriched and expressed in the hydrocarbon plume samples compared with uncontaminated seawater collected from plume depth. In contrast, although genes coding for degradation of more recalcitrant compounds, such as benzene, toluene, ethylbenzene, total xylenes and polycyclic aromatic hydrocarbons, were identified in the metagenomes, they were expressed at low levels, or not at all based on analysis of the metatranscriptomes. Isolation and sequencing of two Oceanospirillales single cells revealed that both cells possessed genes coding for n-alkane and cycloalkane degradation. Specifically, the near-complete pathway for cyclohexane oxidation in the Oceanospirillales single cells was elucidated and supported by both metagenome and metatranscriptome data. The draft genome also included genes for chemotaxis, motility and nutrient acquisition strategies that were also identified in the metagenomes and metatranscriptomes. These data point towards a rapid response of members of the Oceanospirillales to aliphatic hydrocarbons in the deep sea. [ABSTRACT FROM AUTHOR]

We demonstrated previously that Cr(VI) is readily reduced to oxoCr(V)-diols at the surface of Arthrobacter oxydans—a Gram-positive aerobic bacteria isolated from Columbia basalt rocks originated from a highly contaminated site in the USA. Here, we report an electron spin resonance (ESR) study of Cr(III) hydroxide formation from Cr(V)-diols by this bacterial strain as cells were exposed to 35, 200, and 400 mg/L of Cr(VI) under aerobic conditions as a batch culture and as lyophilized cells. The time-dependent ESR measurements show that the half-time of Cr(III) formation is almost equal to that of Cr(V) decomposition, which is in the range of 3–6 days for all cases. This rate is at least 300 times slower than that of Cr(V) formation. Additionally, atomic absorption spectrometry was also employed to examine the time course of total chromium in bacterial cells. This is the first time the kinetics of Cr(III) complexes formation in bacteria is evaluated. [ABSTRACT FROM AUTHOR]

Galectin-1 (Gal-1), a homodimeric prototype of the galectins with a single carbohydrate-recognition domain, was recently identified as being overexpressed in tumor-associated capillary endothelial cells. The role of Gal-1 in endothelial cellular functions and the mechanism of action of Gal-1 remain unknown. Neuropilin-1 (NRP1) is a neuronal receptor that mediates repulsive growth cone guidance, and NRP1 functions in endothelial cells as a coreceptor (with vascular endothelial growth factor receptors (VEGFRs)) for VEGF165. In this study, we found that Gal-1 was overexpressed in the tumor-associated endothelial cells of oral squamous cell carcinomas (P<0.001). Gal-1 increased the proliferation and adhesion of endothelial cells, and enhanced cell migration in combination with VEGF165. Surprisingly, Gal-1 selectively bound NRP1 via the carbohydrate-recognition domain, but did not bind VEGFR-1, VEGFR-2 or VEGFR-3. The Gal-1–NRP1 interaction mediated the migration and adhesion of endothelial cells. The binding of Gal-1 to NRP1 enhanced VEGFR-2 phosphorylation and stimulated the activation of the mitogen activated protein (MAP) kinases SAPK1/JNK (stress activated protein kinase-1/c-Jun NH2-terminal kinase). These findings show, for the first time, that Gal-1 can directly bind to NRP1 on endothelial cells, and can promote the NRP1/VEGFR-2-mediated signaling pathway as well as NRP1-mediated biological activities.Oncogene (2008) 27, 3746–3753; doi:10.1038/sj.onc.1211029; published online 28 January 2008 [ABSTRACT FROM AUTHOR]

The idea that original soft tissue structures and the native structural proteins comprising them can persist across geological time is controversial, in part because rigorous and testable mechanisms that can occur under natural conditions, resulting in such preservation, have not been well defined. Here, we evaluate two non-enzymatic structural protein crosslinking mechanisms, Fenton chemistry and glycation, for their possible contribution to the preservation of blood vessel structures recovered from the cortical bone of a Tyrannosaurus rex (USNM 555000 [formerly, MOR 555]). We demonstrate the endogeneity of the fossil vessel tissues, as well as the presence of type I collagen in the outermost vessel layers, using imaging, diffraction, spectroscopy, and immunohistochemistry. Then, we use data derived from synchrotron FTIR studies of the T. rex vessels to analyse their crosslink character, with comparison against two non-enzymatic Fenton chemistry- and glycation-treated extant chicken samples. We also provide supporting X-ray microprobe analyses of the chemical state of these fossil tissues to support our conclusion that non-enzymatic crosslinking pathways likely contributed to stabilizing, and thus preserving, these T. rex vessels. Finally, we propose that these stabilizing crosslinks could play a crucial role in the preservation of other microvascular tissues in skeletal elements from the Mesozoic. [ABSTRACT FROM AUTHOR]