124 research outputs found
\u3ci\u3eArcynopteryx Compacta\u3c/i\u3e (Plecoptera: Perlodidae), A Holarctic Stonefly Confirmed From Lake Superior, With a Review and First Checklist of the Stoneflies of Michigan
Arcynopteryx compacta, a northern Holarctic species, is confirmed from Lake Superior along the Keweenaw Peninsula of Michigan\u27s Upper Peninsula. A checklist of stoneflies of Michigan is provided, reporting 58 species plus a list of an additional 19 species that are likely to occur in the state
PLECOPTERA OR STONEFLIES (INSECTA) OF INDIANA: DIVERSITY AND CONSERVATION STATUS OF SPECIES
Stoneflies (Plecoptera) are indicators of water quality and have been lost in dramatic numbers from Midwest states, including Indiana. This study synthesizes over 5,000 specimen level records from museums and recent fieldwork to build a current species list, assess watershed level species richness, and calculate state level conservation assessments using NatureServeâs Conservation Rank Calculator. Results include 1,050 positive occurrence records that yielded 92 species. Among these is one recently described species, a new species not yet described, and three previously described species new to Indiana. We have also found additional locations for rare species and confirmed the presence of a few species thought to be extirpated. United States Geological Survey Hierarchical Unit Code scale 6 (HUC6) drainages with the highest species richness values were the Patoka-White (73 species), Lower Ohio-Salt (60 species), and the Wabash River (57 species). The other seven drainages produced from five to 28 species, being limited by low gradient streams due to lake plain landscapes and by stream nutrient enrichment from agriculture. Eleven species were rated as extirpated or presumed extirpated, leaving 81 extant species. Of these, 17 were rated as critically imperiled (S1), 26 imperiled (S2), 25 vulnerable (S3), while only 13 species were rated as secure (S4 & S5). Watersheds and specific streams were discussed for their ability to support individual species or rich assemblages.Indianapolis Zoo funded via Indiana Department of Natural Resourcesunpublishednot peer reviewedOpe
Large-Scale Bioinformatics Analysis of Bacillus Genomes Uncovers Conserved Roles of Natural Products in Bacterial Physiology
ABSTRACT Bacteria possess an amazing capacity to synthesize a diverse range of structurally complex, bioactive natural products known as specialized (or secondary) metabolites. Many of these specialized metabolites are used as clinical therapeutics, while others have important ecological roles in microbial communities. The biosynthetic gene clusters (BGCs) that generate these metabolites can be identified in bacterial genome sequences using their highly conserved genetic features. We analyzed an unprecedented 1,566 bacterial genomes from Bacillus species and identified nearly 20,000 BGCs. By comparing these BGCs to one another as well as a curated set of known specialized metabolite BGCs, we discovered that the majority of Bacillus natural products are comprised of a small set of highly conserved, well-distributed, known natural product compounds. Most of these metabolites have important roles influencing the physiology and development of Bacillus species. We identified, in addition to these characterized compounds, many unique, weakly conserved BGCs scattered across the genus that are predicted to encode unknown natural products. Many of these âsingletonâ BGCs appear to have been acquired via horizontal gene transfer. Based on this large-scale characterization of metabolite production in the Bacilli , we go on to connect the alkylpyrones, natural products that are highly conserved but previously biologically uncharacterized, to a role in Bacillus physiology: inhibiting spore development. IMPORTANCE Bacilli are capable of producing a diverse array of specialized metabolites, many of which have gained attention for their roles as signals that affect bacterial physiology and development. Up to this point, however, the Bacillus genusâs metabolic capacity has been underexplored. We undertook a deep genomic analysis of 1,566 Bacillus genomes to understand the full spectrum of metabolites that this bacterial group can make. We discovered that the majority of the specialized metabolites produced by Bacillus species are highly conserved, known compounds with important signaling roles in the physiology and development of this bacterium. Additionally, there is significant unique biosynthetic machinery distributed across the genus that might lead to new, unknown metabolites with diverse biological functions. Inspired by the findings of our genomic analysis, we speculate that the highly conserved alkylpyrones might have an important biological activity within this genus. We go on to validate this prediction by demonstrating that these natural products are developmental signals in Bacillus and act by inhibiting sporulation
Potassium tert-Butoxide-Catalyzed Dehydrogenative CâH Silylation of Heteroaromatics: A Combined Experimental and Computational Mechanistic Study
We recently reported a new method for the direct dehydrogenative CâH silylation of heteroaromatics utilizing Earth-abundant potassium tert-butoxide. Herein we report a systematic experimental and computational mechanistic investigation of this transformation. Our experimental results are consistent with a radical chain mechanism. A trialkylsilyl radical may be initially generated by homolytic cleavage of a weakened SiâH bond of a hypercoordinated silicon species as detected by IR, or by traces of oxygen which can generate a reactive peroxide by reaction with (KOt-Bu)_4 as indicated by density functional theory (DFT) calculations. Radical clock and kinetic isotope experiments support a mechanism in which the CâSi bond is formed through silyl radical addition to the heterocycle followed by subsequent ÎČ-hydrogen scission. DFT calculations reveal a reasonable energy profile for a radical mechanism and support the experimentally observed regioselectivity. The silylation reaction is shown to be reversible, with an equilibrium favoring products due to the generation of H_2 gas. In situ NMR experiments with deuterated substrates show that H_2 is formed by a cross-dehydrogenative mechanism. The stereochemical course at the silicon center was investigated utilizing a ^2H-labeled silolane probe; complete scrambling at the silicon center was observed, consistent with a number of possible radical intermediates or hypercoordinate silicates
Metal-Catalyzed Addition Polymers for 157 nm Resist Applications. Synthesis and Polymerization of Partially Fluorinated, Ester-Functionalized Tricyclo[4.2.1.0_(2,5)]non-7-enes
Fluorinated tricyclo[4.2.1.0^(2,5)]non-7-ene-3-carboxylic acid esters are shown to undergo metal-catalyzed addition polymerization. The resulting homopolymers are transparent at 157 nm and demonstrate the utility of these monomers in development of photoresists for 157 nm lithography. Fluorinated tricyclononene (TCN) structures with ester substituents exhibit up to 3 orders of magnitude more transparency at 157 nm than conventional ester-functionalized norbornene structures as determined by gas-phase vacuum-ultraviolet spectroscopy and variable angle spectroscopic ellipsometry. Unlike their fluorinated norbornene counterparts, the fluorinated, ester-functionalized TCN monomers successfully undergo transition-metal-catalyzed addition polymerization to produce polymers with high glass transition temperatures and the etch resistance required for photolithographic resist materials applications. The potential use of fluorinated TCN structures for 157 nm photoresists is demonstrated through the synthesis and characterization of TCN monomers and polymers
Breast epithelial cell proliferation is markedly increased with short-term high levels of endogenous estrogen secondary to controlled ovarian hyperstimulation
Oocyte donors have high serum estradiol (E2) levels similar to the serum levels seen in the first trimester of pregnancy. We report in this article our studies comparing cell proliferation, Ki67 (MIB1), and estrogen and progesterone receptor levels (ERα, PRA, and PRB) in the breast terminal duct lobular units of oocyte donors, women in early pregnancy, and in normally cycling women. Breast tissue and blood samples were obtained from 10 oocyte donors, and 30 pregnant women at 5â18 weeks of gestation. Breast tissue samples were also obtained from 26 normally cycling women. In the oocyte donors: peak E2 (mean ~15,300 pmol/l) was reached on the day before oocyte (and tissue) donation; peak progesterone (P4; mean 36.3 nmol/l) was reached on the day of donation; Ki67 was positively associated with level of E2, and the mean Ki67 was 7.0% significantly greater than the mean 1.8% of cycling women. In the pregnant women: mean E2 rose from ~2,000 pmol/l at 5 weeks of gestation to ~27,000 pmol/l at 18 weeks; mean P4 did not change from ~40 nmol/l until around gestational week 11 when it increased to ~80 nmol/l; mean Ki67 was 15.4% and did not vary with gestational age or E2. Oocyte donors have greatly increased levels of E2 and of breast-cell proliferation, both comparable in the majority of donors to the levels seen in the first trimester of pregnancy. Whether their short durations of greatly increased E2 levels are associated with any long-term beneficial effects on the breast, as occurring in rodent models, is not known
Fungal Origins of the Bicyclo[2.2.2]diazaoctane Ring System of Prenylated Indole Alkaloids
Over eight different families of natural products, consisting of nearly seventy secondary metabolites, which contain the bicyclo[2.2.2]diazaoctane ring system, have been isolated from various Aspergillus, Penicillium, and Malbranchea species. Since 1968, these secondary metabolites have been the focus of numerous biogenetic, synthetic, taxonomic, and biological studies, and, as such, have made a lasting impact across multiple scientific disciplines. This review covers the isolation, biosynthesis, and biological activity of these unique secondary metabolites containing the bridging bicyclo[2.2.2]diazaoctane ring system. Furthermore, the diverse fungal origin of these natural products is closely examined and, in many cases, updated to reflect the currently accepted fungal taxonomy
The Genome Sequence of the Leaf-Cutter Ant Atta cephalotes Reveals Insights into Its Obligate Symbiotic Lifestyle
Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of hostâmicrobe symbioses
Autonomous Application of Quantitative PCR in the Deep Sea: In Situ Surveys of Aerobic Methanotrophs Using the Deep-Sea Environmental Sample Processor
Allocapnia tsalagi Grubbs, 2008, sp. nov.
<i>Allocapnia tsalagi</i> sp. nov. <p>(Figs. 1A–F)</p> <p> <b>Male</b>. Body length 4.0–4.5 mm. Wings reaching 8th or 9th abdominal tergite. Dorsal process of 8th tergite situated on high plateau, forming a wide, broadly-arcuate transverse bar directed slightly anterad; tuberculate and noticeably arcuate when viewed dorsally, the concavity directed posteriorly (Figs. 1A–B). Apical segment of epiproct dorsal limb approximately 1.5X length of basal segment, expanded slightly in posterior half in lateral view, with a small subapical indentation (Fig. 1C–D); narrow profile in dorsal view, expanded slightly in posterior third (Fig. 1E).</p> <p> <b>Female</b>. Body length 5.0–5.5 mm. Wings reaching 9th tergite to beyond tip of abdomen. Eighth abdominal sternite heavily sclerotized medially, gently concave posteriorly with a small medial subtriangular nipple (Fig. 1F); separated from 7th sternite by membrane.</p> <p> <b>Material examined</b>. Holotype male, U.S.A., Alabama, Jackson Co., spring into unnamed tributary to Big Coon Creek, 4 km NE Hytop, 34° 56.48'N, 086° 03.84'W, 9 II 2008, S. A. Grubbs (SAG) (INHS); Paratypes, same location as holotype but 1 male, 2 female (INHS; WKU); same location as holotype but 6 II 2008, 3 males (WKU); spring into Larkin Fork, Paint Rock River, Rte. 65, 3 km SE Francisco, 19 II 2007, 1 male, 1 female, SAG (WKU).</p> <p> <b>Etymology</b>. The species name <i>tsalagi</i> is in reference to Cherokee Native Americans, who occupied this region of northeastern Alabama prior to the Indian Removal Act of 1830. The word Tsalagi is Choctaw for “cave-land-people”, an appropriate reference to the well-developed karst landscape in this area. The common name, Tsalagi snowfly, is proposed for this species (Stark <i>et al</i>. 1998).</p> <p> <b>Diagnosis</b>. Ross & Ricker (1971) defined the <i>A. recta</i> group according to both male and female characteristics. Males lack a dorsal process on the 7th abdominal tergite and possess a single arcuate or incised process that is perched on the 8th abdominal tergite. The 7th and 8th female abdominal sternites are separated by a membrane and the 8th sternite is either unmodified or scarcely modified posteriorly. Using these criteria <i>A. tsalagi</i> can be readily assigned to the <i>A. recta</i> group, which includes <i>A. loshada</i> Ricker, <i>A. malverna</i> Ross, <i>A. mohri</i> Ross & Ricker, <i>A. polemistis</i> Ross & Ricker, <i>A. recta</i>, <i>A. sano</i> Grubbs, <i>A. sequatchie</i> Kondratieff & Kirchner, and <i>A. starki</i> Kondratieff & Kirchner.</p> <p> The arcuate dorsal process on the 8th abdominal tergite of <i>A. tsalagi</i> (Fig. 1A) is similar only to <i>A. malverna</i> and <i>A. mohri</i> (Figs. 2A–B). The thin, blade-like upper limb of the epiproct of <i>A. mohri</i> (Figs. 2C–D) is distinguished readily from the posteriorly-expanded limbs of <i>A. malverna</i> (Figs. 2E–F) and <i>A. tsalagi</i> (Fig. 1E). Although the upper limb is approximately 1.5X the length of the basal segment for both <i>A. tsalagi</i> and <i>A.</i></p> <p> <i>malverna</i>, the upper limb of <i>A. tsalagi</i> (Figs. 1C, 1E) is considerably more elongate than <i>A. malverna</i> in both dorsal and lateral (Figs. 2C–D) aspects. The upper limb of <i>A. malverna</i> is more apically robust and expanded posteriorly, but lacks the subapical indentation that is exhibited by <i>A. tsalagi</i>. In addition, the dorsal process of the 8th abdominal tergite of <i>A. tsalagi</i> is noticeably directed more anteriorly (Fig. 1D) than both <i>A. mohri</i> (Fig. 2C) and <i>A. malverna</i> (Fig. 2E).</p> <p> The females of both <i>A. malverna</i> and <i>A. mohri</i> typically possess a small, posteromedial projection on the 8th abdominal sternite, a characteristic that is similarly exhibited by <i>A. tsalagi</i> and prevents objective differentiation between the three species. Although <i>A. tsalagi</i> is geographically isolated from both <i>A. malverna</i> and <i>A. mohri</i>, females of <i>A. recta</i> sometimes display a rounded medial projection on the 8th sternite. <i>Allocapnia recta</i> inhabits a wide array of stream sizes and occurs commonly in northeastern Alabama. <i>Allocapnia malverna</i> possesses mainly a Gulf Coastal Plain distribution in Louisiana and Texas with a few scattered localities in Arkansas and Oklahoma, while <i>A</i>. <i>mohri</i> occurs in the Ouachita and Ozark Mountains of Arkansas, Missouri, and Oklahoma (Kondratieff & Baumann 2000; Stark <i>et al.</i> 2008).</p> <p> <b>Remarks</b>. <i>Allocapnia tsalagi</i> has been collected only from the type locality and the Larkin Fork spring. Both sites are small springs and all material was obtained near their respective sources. The type locality is wetted permanently only for a short distance (<50 m) from the source except during high precipitation events. The sole stonefly species collected with <i>A</i>. <i>tsalagi</i> at the holotype locality was <i>Soyedina</i> cf. <i>vallicularia</i> (Wu). <i>Zealeuctra fraxina</i> Ricker & Ross and <i>S</i>. cf. <i>vallicularia</i> were the only stonefly species obtained with <i>A</i>. <i>tsalagi</i> at the Larkin Fork spring.</p> <p> The discovery of <i>A. tsalagi</i> is particularly surprising given the recent description of <i>A. sano</i> from a small, calcareous spring in north-central Alabama (Grubbs 2006). The type localities of the two species are separated by only ca. 50 km. <i>Allocapnia tsalagi</i> and <i>A. sano</i> appear to be restricted to springs within the Cumberland Plateau region. <i>Allocapnia tsalagi</i> should be found from additional habitats both in Alabama and north into southern Tennessee.</p>Published as part of <i>Grubbs, Scott A., 2008, Allocapnia tsalagi, sp. n. and notes on A. recta (Claassen) from the Cumberland Plateau region of northeastern Alabama, U. S. A., pp. 63-68 in Zootaxa 1754</i> on pages 63-66, DOI: <a href="http://zenodo.org/record/181778">10.5281/zenodo.181778</a>
- âŠ