Publications by authors named "James A Counts"

Purpose Of The Review: Nonhuman primates (NHPs) are seen as the closest animal model to humans in terms of anatomy and immune system makeup. Here, we review how preclinical studies in this model system are teaching the field of HIV vaccinology the basic immunology that is needed to induce broadly neutralizing antibodies (bnAbs) with vaccination and elicit protective T cell responses. These lessons are being translated into clinical trials to advance towards protective active vaccination against HIV-1 infection.

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Within the extremely thermoacidophilic Sulfolobaceae, the capacity to oxidize iron varies considerably. While some species are prolific iron oxidizers (e.g.

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Thermoacidophilic archaea belonging to the order Sulfolobales thrive in extreme biotopes, such as sulfuric hot springs and ore deposits. These microorganisms have been model systems for understanding life in extreme environments, as well as for probing the evolution of both molecular genetic processes and central metabolic pathways. Thermoacidophiles, such as the Sulfolobales, use typical microbial responses to persist in hot acid (e.

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The order Sulfolobales was one of the first named Archaeal lineages, with globally distributed members from terrestrial thermal acid springs (pH < 4; T > 65°C). The Sulfolobales represent broad metabolic capabilities, ranging from lithotrophy, based on inorganic iron and sulfur biotransformations, to autotrophy, to chemoheterotrophy in less acidophilic species. Components of the 3-hydroxypropionate/4-hydroxybutyrate carbon fixation cycle, as well as sulfur oxidation, are nearly universally conserved, although dissimilatory sulfur reduction and disproportionation (Acidianus, Stygiolobus and Sulfurisphaera) and iron oxidation (Acidianus, Metallosphaera, Sulfurisphaera, Sulfuracidifex and Sulfodiicoccus) are limited to fewer lineages.

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Presented are five genomes from the polyextremophilic (optimal temperature of >65°C and optimal pH of <3.5) archaeal family , greatly expanding order-wide genomic diversity. Included are the only obligate anaerobic species, several facultative sulfur utilizers, two metal mobilizers, one facultative chemolithoautotroph with robust metabolic versatility, and some of the most thermophilic thermoacidophiles reported to date.

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Species in the archaeal order Sulfolobales thrive in hot acid and exhibit remarkable metabolic diversity. Some species are chemolithoautotrophic, obtaining energy through the oxidation of inorganic substrates, sulphur in particular, and acquiring carbon through the 3-hydroxypropionate/4-hydroxybutyrate (3-HP/4-HB) CO -fixation cycle. The current model for sulphur oxidation in the Sulfolobales is based on the biochemical analysis of specific proteins from Acidianus ambivalens, including sulphur oxygenase reductase (SOR) that disproportionates S° into H S and sulphite (SO ).

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Certain species from the extremely thermoacidophilic genus directly oxidize Fe(II) to Fe(III), which in turn catalyzes abiotic solubilization of copper from chalcopyrite to facilitate recovery of this valuable metal. In this process, the redox status of copper does not change as it is mobilized. species can also catalyze the release of metals from ores with a change in the metal's redox state.

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The family Sulfolobaceae contains extremely thermoacidophilic archaea that are found in terrestrial environments. Here, we report three closed genomes from two currently defined genera within the family, namely, Acidianus brierleyi DSM-1651, Acidianus sulfidivorans DSM-18786, and Metallosphaera hakonensis DSM-7519.

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Although the extremely thermophilic archaea (Topt ≥ 70°C) may be the most primitive extant forms of life, they have been studied to a limited extent relative to mesophilic microorganisms. Many of these organisms have unique biochemical and physiological characteristics with important biotechnological implications. These include methanogens that generate methane, fermentative anaerobes that produce hydrogen gas with high efficiency, and acidophiles that can mobilize base, precious and strategic metals from mineral ores.

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When abruptly exposed to toxic levels of hexavalent uranium, the extremely thermoacidophilic archaeon Metallosphaera prunae, originally isolated from an abandoned uranium mine, ceased to grow, and concomitantly exhibited heightened levels of cytosolic ribonuclease activity that corresponded to substantial degradation of cellular RNA. The M. prunae transcriptome during 'uranium-shock' implicated VapC toxins as possible causative agents of the observed RNA degradation.

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The current upper thermal limit for life as we know it is approximately 120°C. Microorganisms that grow optimally at temperatures of 75°C and above are usually referred to as 'extreme thermophiles' and include both bacteria and archaea. For over a century, there has been great scientific curiosity in the basic tenets that support life in thermal biotopes on earth and potentially on other solar bodies.

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