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2.
J Law Med Ethics ; 51(3): 485-489, 2023.
Article in English | MEDLINE | ID: mdl-38088610

ABSTRACT

Dobbs v. Jackson Women's Health continues a trajectory of U.S. Supreme Court jurisprudence that undermines the normative foundation of public health - the idea that the state is obligated to provide a robust set of supports for healthcare services and the underlying social determinants of health. Dobbs furthers a longstanding ideology of individual responsibility in public health, neglecting collective responsibility for better health outcomes. Such an ideology on individual responsibility not only enables a shrinking of public health infrastructure for reproductive health, it facilitates the rise of reproductive coercion and a criminal legal response to pregnancy and abortion. This commentary situates Dobbs in the context of a long historical shift in public health that increasingly places burdens on individuals for their own reproductive health care, moving away from the possibility of a robust state public health infrastructure.


Subject(s)
Abortion, Induced , Coercion , Pregnancy , Female , Humans , United States , Women's Rights , Public Health , Women's Health , Supreme Court Decisions
3.
Mol Ecol ; 32(20): 5479-5497, 2023 10.
Article in English | MEDLINE | ID: mdl-37702957

ABSTRACT

Studies of species that experience environmental heterogeneity across their distributions have become an important tool for understanding mechanisms of adaptation and predicting responses to climate change. We examine population structure, demographic history and environmentally associated genomic variation in Bombus vosnesenskii, a common bumble bee in the western USA, using whole genome resequencing of populations distributed across a broad range of latitudes and elevations. We find that B. vosnesenskii exhibits minimal population structure and weak isolation by distance, confirming results from previous studies using other molecular marker types. Similarly, demographic analyses with Sequentially Markovian Coalescent models suggest that minimal population structure may have persisted since the last interglacial period, with genomes from different parts of the species range showing similar historical effective population size trajectories and relatively small fluctuations through time. Redundancy analysis revealed a small amount of genomic variation explained by bioclimatic variables. Environmental association analysis with latent factor mixed modelling (LFMM2) identified few outlier loci that were sparsely distributed throughout the genome and although a few putative signatures of selective sweeps were identified, none encompassed particularly large numbers of loci. Some outlier loci were in genes with known regulatory relationships, suggesting the possibility of weak selection, although compared with other species examined with similar approaches, evidence for extensive local adaptation signatures in the genome was relatively weak. Overall, results indicate B. vosnesenskii is an example of a generalist with a high degree of flexibility in its environmental requirements that may ultimately benefit the species under periods of climate change.


Subject(s)
Sequence Analysis, DNA , Bees/genetics , Animals , Population Density , North America
4.
Semin Perinatol ; 47(5): 151784, 2023 08.
Article in English | MEDLINE | ID: mdl-37357043

ABSTRACT

The benefits of delayed cord clamping have been investigated in multiple studies and supported by various professional associations. Other aspects of umbilical cord management strategies occurring after cord clamping have not been fully thoroughly analyzed. This article will explore and deliberate elements of umbilical cord nonseverance, vascular access management, and blood banking.


Subject(s)
Parturition , Umbilical Cord , Pregnancy , Female , Humans , Constriction , Time Factors , Blood Banking
5.
J Perinatol ; 42(8): 1083-1090, 2022 08.
Article in English | MEDLINE | ID: mdl-34725448

ABSTRACT

OBJECTIVE: To explore LGBTQI+ parental experiences regarding their interactions with healthcare professionals as a resource for feeding options during the prenatal-to-neonatal period. STUDY DESIGN: This single-center, interview-based qualitative study of LGBTQI+ parents utilized grounded theory to identify and verify emergent themes and subthemes. We developed a conceptual framework to illustrate relationships among themes and subthemes, as well as opportunities for healthcare professionals and families to improve LGBTQI+ parental support. RESULTS: Thematic saturation was attained after interviewing 21 parents from 12 families. Analyses revealed four main themes representing opportunities for improvement: education, continuity of care, parental engagement and open communication. Personal and interpersonal factors influenced parental experiences and decisions, which shaped ultimate feeding outcomes. CONCLUSIONS: LGBTQI+ parents revealed challenges of establishing feeding practices that best aligned with their values and goals. Recognizing these factors can help healthcare professionals improve their counseling, engagement and support of LGBTQI+ parents.


Subject(s)
Decision Making , Professional-Family Relations , Delivery of Health Care , Grounded Theory , Humans , Infant , Infant, Newborn , Parents/psychology , Qualitative Research
6.
Sci Rep ; 10(1): 17063, 2020 10 13.
Article in English | MEDLINE | ID: mdl-33051510

ABSTRACT

Global temperature changes have emphasized the need to understand how species adapt to thermal stress across their ranges. Genetic mechanisms may contribute to variation in thermal tolerance, providing evidence for how organisms adapt to local environments. We determine physiological thermal limits and characterize genome-wide transcriptional changes at these limits in bumble bees using laboratory-reared Bombus vosnesenskii workers. We analyze bees reared from latitudinal (35.7-45.7°N) and altitudinal (7-2154 m) extremes of the species' range to correlate thermal tolerance and gene expression among populations from different climates. We find that critical thermal minima (CTMIN) exhibit strong associations with local minimums at the location of queen origin, while critical thermal maximum (CTMAX) was invariant among populations. Concordant patterns are apparent in gene expression data, with regional differentiation following cold exposure, and expression shifts invariant among populations under high temperatures. Furthermore, we identify several modules of co-expressed genes that tightly correlate with critical thermal limits and temperature at the region of origin. Our results reveal that local adaptation in thermal limits and gene expression may facilitate cold tolerance across a species range, whereas high temperature responses are likely constrained, both of which may have implications for climate change responses of bumble bees.


Subject(s)
Bees/genetics , Bees/physiology , Acclimatization/genetics , Acclimatization/physiology , Animals , California , Climate Change , Female , Gene Expression , Gene Ontology , Genes, Insect , Heat-Shock Response/genetics , Heat-Shock Response/physiology , Oregon , Phylogeography , Stress, Physiological/genetics , Stress, Physiological/physiology , Temperature
7.
Breastfeed Med ; 15(5): 284-293, 2020 05.
Article in English | MEDLINE | ID: mdl-32330392

ABSTRACT

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.


Subject(s)
Breast Feeding , Lactation , Sexual and Gender Minorities , Transgender Persons , Clinical Protocols , Female , Humans , Infant , Minority Health , Societies, Medical
8.
Mol Ecol ; 29(5): 920-939, 2020 03.
Article in English | MEDLINE | ID: mdl-32031739

ABSTRACT

Understanding evolutionary responses to variation in temperature and precipitation across species ranges is of fundamental interest given ongoing climate change. The importance of temperature and precipitation for multiple aspects of bumble bee (Bombus) biology, combined with large geographic ranges that expose populations to diverse environmental pressures, make these insects well-suited for studying local adaptation. Here, we analyzed genome-wide sequence data from two widespread bumble bees, Bombus vosnesenskii and Bombus vancouverensis, using multiple environmental association analysis methods to investigate climate adaptation across latitude and altitude. The strongest signatures of selection were observed in B. vancouverensis, but despite unique responses between species for most loci, we detected several shared responses. Genes relating to neural and neuromuscular function and ion transport were especially evident with respect to temperature variables, while genes relating to cuticle formation, tracheal and respiratory system development, and homeostasis were associated with precipitation variables. Our data thus suggest that adaptive responses for tolerating abiotic variation are likely to be complex, but that several parallels among species can emerge even for these complex traits and landscapes. Results provide the framework for future work into mechanisms of thermal and desiccation tolerance in bumble bees and a set of genomic targets that might be monitored for future conservation efforts.


Subject(s)
Acclimatization , Bees/genetics , Climate , Altitude , Animals , Bees/classification , California , Genetics, Population , Genome, Insect , Oregon , Polymorphism, Single Nucleotide , Washington
9.
Mol Ecol ; 27(14): 2926-2942, 2018 07.
Article in English | MEDLINE | ID: mdl-29862596

ABSTRACT

Identifying drivers of dispersal limitation and genetic differentiation is a key goal in biogeography. We examine patterns of population connectivity and genetic diversity using restriction site-associated DNA sequencing (RADseq) in two bumble bee species, Bombus vosnesenskii and Bombus bifarius, across latitude and altitude in mountain ranges from California, Oregon and Washington, U.S.A. Bombus vosnesenskii, which occurs across a broader elevational range at most latitudes, exhibits little population structure while B. bifarius, which occupies a relatively narrow higher elevation niche across most latitudes, exhibits much stronger population differentiation, although gene flow in both species is best explained by isolation with environmental niche resistance. A relationship between elevational habitat breadth and genetic diversity is also apparent, with B. vosnesenskii exhibiting relatively consistent levels of genetic diversity across its range, while B. bifarius has reduced genetic diversity at low latitudes, where it is restricted to high-elevation habitat. The results of this study highlight the importance of the intersect between elevational range and habitat suitability in influencing population connectivity and suggest that future climate warming will have a fragmenting effect even on populations that are presently well connected, as they track their thermal niches upward in montane systems.


Subject(s)
Bees/genetics , Genetic Variation , Microsatellite Repeats/genetics , Pollination/genetics , Altitude , Animals , Bees/growth & development , California , Ecosystem , Gene Flow/genetics , Genotype , Oregon , Sequence Analysis, DNA , Washington
10.
J Physiol ; 596(14): 2901-2916, 2018 07.
Article in English | MEDLINE | ID: mdl-29797443

ABSTRACT

KEY POINTS: Cigarette smoke components directly alter muscle fatigue resistance and intracellular muscle fibre Ca2+ handling independent of a change in lung structure. Changes in muscle vascular structure are associated with a depletion of satellite cells. Sarcoplasmic reticulum Ca2+ uptake is substantially impaired in myofibres during fatiguing contractions in mice treated with cigarette smoke extract. ABSTRACT: Cigarette smokers exhibit exercise intolerance before a decline in respiratory function. In the present study, the direct effects of cigarette smoke on limb muscle function were tested by comparing cigarette smoke delivered to mice by weekly injections of cigarette smoke extract (CSE), or nose-only exposure (CS) 5 days each week, for 8 weeks. Cigarette smoke delivered by either route did not alter pulmonary airspace size. Muscle fatigue measured in situ was 50% lower in the CSE and CS groups than in control. This was accompanied by 34% and 22% decreases in soleus capillary-to-fibre ratio of the CSE and CS groups, respectively, and a trend for fewer skeletal muscle actin-positive arterioles (P = 0.07). In addition, fewer quiescent satellite cells (Nes+Pax7+) were associated with soleus fibres in mice with skeletal myofibre VEGF gene deletion (decreased 47%) and CS exposed (decreased 73%) than with control fibres. Contractile properties of isolated extensor digitorum longus and soleus muscles were impaired. In flexor digitorum brevis myofibres isolated from CSE mice, fatigue resistance was diminished by 43% compared to control and CS myofibres, and this was accompanied by a pronounced slowing in relaxation, an increase in intracellular Ca2+ accumulation, and a slowing in sarcoplasmic reticulum Ca2+ uptake. These data suggest that cigarette smoke components may impair hindlimb muscle vascular structure, fatigue resistance and myofibre calcium handling, and these changes ultimately affect contractile efficiency of locomotor muscles independent of a change in lung function.


Subject(s)
Muscle Contraction , Muscle Fibers, Skeletal/pathology , Muscle, Skeletal/pathology , Muscular Diseases/pathology , Sarcoplasmic Reticulum/pathology , Smoking/adverse effects , Animals , Capillaries , Male , Mice , Mice, Inbred C57BL , Muscle, Skeletal/blood supply , Muscular Diseases/etiology , Sarcoplasmic Reticulum/metabolism
11.
Ecol Evol ; 7(10): 3406-3413, 2017 05.
Article in English | MEDLINE | ID: mdl-28515876

ABSTRACT

Variation in bumble bee color patterns is well-documented within and between species. Identifying the genetic mechanisms underlying such variation may be useful in revealing evolutionary forces shaping rapid phenotypic diversification. The widespread North American species Bombus bifarius exhibits regional variation in abdominal color forms, ranging from red-banded to black-banded phenotypes and including geographically and phenotypically intermediate forms. Identifying genomic regions linked to this variation has been complicated by strong, near species level, genome-wide differentiation between red- and black-banded forms. Here, we instead focus on the closely related black-banded and intermediate forms that both belong to the subspecies B. bifarius nearcticus. We analyze an RNA sequencing (RNAseq) data set and identify a cluster of single nucleotide polymorphisms (SNPs) within one gene, Xanthine dehydrogenase/oxidase-like, that exhibit highly unusual differentiation compared to the rest of the sequenced genome. Homologs of this gene contribute to pigmentation in other insects, and results thus represent a strong candidate for investigating the genetic basis of pigment variation in B. bifarius and other bumble bee mimicry complexes.

12.
Ecol Evol ; 6(4): 1075-91, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26811748

ABSTRACT

Geographic variation in insect coloration is among the most intriguing examples of rapid phenotypic evolution and provides opportunities to study mechanisms of phenotypic change and diversification in closely related lineages. The bumble bee Bombus bifarius comprises two geographically disparate color groups characterized by red-banded and black-banded abdominal pigmentation, but with a range of spatially and phenotypically intermediate populations across western North America. Microsatellite analyses have revealed that B. bifarius in the USA are structured into two major groups concordant with geography and color pattern, but also suggest ongoing gene flow among regional populations. In this study, we better resolve the relationships among major color groups to better understand evolutionary mechanisms promoting and maintaining such polymorphism. We analyze >90,000 and >25,000 single-nucleotide polymorphisms derived from transcriptome (RNAseq) and double digest restriction site associated DNA sequencing (ddRAD), respectively, in representative samples from spatial and color pattern extremes in B. bifarius as well as phenotypic and geographic intermediates. Both ddRAD and RNAseq data illustrate substantial genome-wide differentiation of the red-banded (eastern) color form from both black-banded (western) and intermediate (central) phenotypes and negligible differentiation among the latter populations, with no obvious admixture among bees from the two major lineages. Results thus indicate much stronger background differentiation among B. bifarius lineages than expected, highlighting potential challenges for revealing loci underlying color polymorphism from population genetic data alone. These findings will have significance for resolving taxonomic confusion in this species and in future efforts to investigate color-pattern evolution in B. bifarius and other polymorphic bumble bee species.

13.
J Patient Saf ; 9(2): 103-9, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23697982

ABSTRACT

INTRODUCTION: Medication errors account for 20% of medical errors in the United States with the largest risk at prescribing and administration. Analgesics or opioids are frequently used medications that can be associated with patient harm when prescribed or administered improperly. In an effort to decrease medication errors, Duke University Hospital implemented clinical decision support via computer provider order entry (CPOE) and "smart pump" technology, 2/2008, with the goal to decrease patient-controlled analgesia (PCA) adverse events. METHODS: This project evaluated PCA safety events, reviewing voluntary report system and adverse drug events via surveillance (ADE-S), on intermediate and step-down units preimplementation and postimplementation of clinical decision support via CPOE and PCA smart pumps for the prescribing and administration of opioids therapy in the adult patient requiring analgesia for acute pain. DISCUSSION: Voluntary report system and ADE-S PCA events decreased based upon 1000 PCA days; ADE-S PCA events per 1000 PCA days decreased 22%, from 5.3 (pre) to 4.2 (post) (P = 0.09). Voluntary report system events decreased 72%, from 2.4/1000 PCA days (pre) to 0.66/1000 PCA days (post) and was statistically significant (P < 0.001). There was a difference in the ADE-S data for causality (P < 0.0001) with sleep apnea and renal insufficiency approaching significance. Voluntary report system safety event were statistically significant for obesity [body mass index (BMI) ≥30] and weight. CONCLUSION: This study demonstrated a decrease in PCA events between time periods in both the ADE-S and voluntary report system data, thus supporting the recommendation of clinical decision support via CPOE and PCA smart pump technology.


Subject(s)
Acute Pain/drug therapy , Analgesia, Patient-Controlled/instrumentation , Analgesics, Opioid/administration & dosage , Decision Support Systems, Clinical , Drug-Related Side Effects and Adverse Reactions/prevention & control , Infusion Pumps , Medication Errors/prevention & control , Patient Safety , Adult , Aged , Analgesia, Patient-Controlled/adverse effects , Analgesics, Opioid/adverse effects , Drug-Related Side Effects and Adverse Reactions/epidemiology , Female , Hospitals, University , Humans , Male , Medical Order Entry Systems , Middle Aged , North Carolina/epidemiology , Retrospective Studies , United States , Young Adult
14.
J Biol Chem ; 286(22): 20043-53, 2011 Jun 03.
Article in English | MEDLINE | ID: mdl-21507955

ABSTRACT

Alternative splicing is typically controlled by complexes of regulatory proteins that bind to sequences within or flanking variable exons. The identification of regulatory sequence motifs and the characterization of sequence motifs bound by splicing regulatory proteins have been essential to predicting splicing regulation. The activation-responsive sequence (ARS) motif has previously been identified in several exons that undergo changes in splicing upon T cell activation. hnRNP L binds to this ARS motif and regulates ARS-containing exons; however, hnRNP L does not function alone. Interestingly, the proteins that bind together with hnRNP L differ for different exons that contain the ARS core motif. Here we undertake a systematic mutational analysis of the best characterized context of the ARS motif, namely the ESS1 sequence from CD45 exon 4, to understand the determinants of binding specificity among the components of the ESS1 regulatory complex and the relationship between protein binding and function. We demonstrate that different mutations within the ARS motif affect specific aspects of regulatory function and disrupt the binding of distinct proteins. Most notably, we demonstrate that the C77G polymorphism, which correlates with autoimmune disease susceptibility in humans, disrupts exon silencing by preventing the redundant activity of hnRNPs K and E2 to compensate for the weakened function of hnRNP L. Therefore, these studies provide an important example of the functional relevance of combinatorial function in splicing regulation and suggest that additional polymorphisms may similarly disrupt function of the ESS1 silencer.


Subject(s)
Alternative Splicing/genetics , Autoimmune Diseases , Genetic Diseases, Inborn , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , Leukocyte Common Antigens , Polymorphism, Single Nucleotide , Autoimmune Diseases/genetics , Autoimmune Diseases/metabolism , Cell Line , Exons/genetics , Genetic Diseases, Inborn/genetics , Genetic Diseases, Inborn/metabolism , Heterogeneous-Nuclear Ribonucleoproteins/genetics , Humans , Leukocyte Common Antigens/biosynthesis , Leukocyte Common Antigens/genetics , Lymphocyte Activation/genetics , Mutation , Silencer Elements, Transcriptional/genetics , T-Lymphocytes/metabolism
15.
Mol Cell Biol ; 31(11): 2184-95, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21444716

ABSTRACT

The HMG-box transcription factor LEF1 controls many developmentally regulated genes, including genes that activate expression of the T-cell antigen receptor alpha chain (TCR-alpha) in developing thymocytes. At least two distinct isoforms of LEF1 are expressed, resulting from variable inclusion of LEF1 exon 6; however, the expression pattern of these isoforms and mechanism of splicing regulation have not been explored. Here we demonstrate that inclusion of LEF1 exon 6 is increased during thymic development and in response to signaling in a cultured T-cell line in a manner which temporally correlates with increased expression of TCR-alpha. We further find that inclusion of exon 6 is dependent on the signal-induced increase in expression and binding of the splicing factor CELF2 to two intronic sequences flanking the regulated exon. Importantly, loss of exon 6 inclusion, through knockdown of CELF2 or direct block of the exon 6 splice site, results in reduced expression of TCR-alpha mRNA. Together, these data establish the mechanistic basis of LEF1 splicing regulation and demonstrate that LEF1 alternative splicing is a contributing determinant in the optimal expression of the TCR-alpha chain.


Subject(s)
Alternative Splicing , Lymphoid Enhancer-Binding Factor 1/genetics , Lymphoid Enhancer-Binding Factor 1/metabolism , Nerve Tissue Proteins/metabolism , RNA-Binding Proteins/metabolism , T-Lymphocytes/metabolism , Animals , Base Sequence , Blotting, Western , CELF Proteins , Cell Line , Exons , Gene Knockdown Techniques , Humans , Lymphocyte Activation , Mice , Molecular Sequence Data , Polymerase Chain Reaction , Protein Isoforms , Receptors, Antigen, T-Cell, alpha-beta/biosynthesis , T-Lymphocytes/immunology , Tetradecanoylphorbol Acetate/pharmacology , Thymus Gland/embryology
17.
RNA ; 14(10): 2038-49, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18719244

ABSTRACT

The human CD45 gene encodes a protein-tyrosine phosphatase that exhibits differential isoform expression in resting and activated T cells due to alternative splicing of three variable exons. Previously, we have used biochemical methods to identify two regulatory proteins, hnRNP L and PSF, which contribute to the activation-induced skipping of CD45 via the ESS1 regulatory element in variable exon 4. Here we report the identification of a third CD45 regulatory factor, hnRNP L-like (hnRNP LL), via a cell-based screen for clonal variants that exhibit an activation-like phenotype of CD45 splicing even under resting conditions. Microarray analysis of two splicing-altered clones revealed increased expression of hnRNP LL relative to wild-type cells. We further demonstrate that both the expression of hnRNP LL protein and its binding to ESS1 are up-regulated in wild-type cells upon activation. Forced overexpression of hnRNP LL in wild-type cells results in an increase in exon repression, while knock-down of hnRNP LL eliminates activation-induced exon skipping. Interestingly, analysis of the binding of hnRNP L and hnRNP LL to mutants of ESS1 reveals that these proteins have overlapping, but distinct binding requirements. Together, these data establish that hnRNP LL plays a critical and unique role in the signal-induced regulation of CD45 and demonstrate the utility of cell-based screens for the identification of novel splicing regulatory factors.


Subject(s)
Gene Expression Regulation, Enzymologic , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , Leukocyte Common Antigens/genetics , RNA Splicing , Repressor Proteins/metabolism , Exons , Genes, Reporter , Genetic Variation , Heterogeneous-Nuclear Ribonucleoproteins/genetics , Humans , Lymphocyte Activation , Mutation , Oligonucleotide Array Sequence Analysis , Regulatory Elements, Transcriptional , Repressor Proteins/genetics , T-Lymphocytes/immunology , Up-Regulation
18.
Mol Cell Biol ; 27(19): 6972-84, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17664280

ABSTRACT

Cells can regulate their protein repertoire in response to extracellular stimuli via alternative splicing; however, the mechanisms controlling this process are poorly understood. The CD45 gene undergoes alternative splicing in response to T-cell activation to regulate T-cell function. The ESS1 splicing silencer in CD45 exon 4 confers basal exon skipping in resting T cells through the activity of hnRNP L and confers activation-induced exon skipping in T cells via previously unknown mechanisms. Here we have developed an in vitro splicing assay that recapitulates the signal-induced alternative splicing of CD45 and demonstrate that cellular stimulation leads to two changes to the ESS1-bound splicing regulatory complex. Activation-induced posttranslational modification of hnRNP L correlates with a modest increase in the protein's repressive activity. More importantly, the splicing factor PSF is recruited to the ESS1 complex in an activation-dependent manner and accounts for the majority of the signal-regulated ESS1 activity. The associations of hnRNP L and PSF with the ESS1 complex are largely independent of each other, but together these proteins account for the total signal-regulated change in CD45 splicing observed in vitro and in vivo. Such a combinatorial effect on splicing allows for precise regulation of signal-induced alternative splicing.


Subject(s)
Alternative Splicing , Exons , Gene Expression Regulation , Heterogeneous-Nuclear Ribonucleoprotein L/metabolism , Leukocyte Common Antigens , RNA-Binding Proteins/metabolism , Animals , Cell Line , Heterogeneous-Nuclear Ribonucleoprotein L/genetics , Leukocyte Common Antigens/genetics , Leukocyte Common Antigens/metabolism , PTB-Associated Splicing Factor , Protein Processing, Post-Translational , RNA Precursors/metabolism , RNA-Binding Proteins/genetics
19.
Appl Environ Microbiol ; 71(9): 5544-50, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16151147

ABSTRACT

Fungi are an important and diverse component of soil communities, but these communities have proven difficult to study in conventional biotic surveys. We evaluated soil fungal diversity at two sites in a temperate forest using direct isolation of small-subunit and internal transcribed spacer (ITS) rRNA genes by PCR and high-throughput sequencing of cloned fragments. We identified 412 sequence types from 863 fungal ITS sequences, as well as 112 ITS sequences from other eukaryotic microorganisms. Equal proportions of Basidiomycota and Ascomycota sequences were present in both the ITS and small-subunit libraries, while members of other fungal phyla were recovered at much lower frequencies. Many sequences closely matched sequences from mycorrhizal, plant-pathogenic, and saprophytic fungi. Compositional differences were observed among samples from different soil depths, with mycorrhizal species predominating deeper in the soil profile and saprophytic species predominating in the litter layer. Richness was consistently lowest in the deepest soil horizon samples. Comparable levels of fungal richness have been observed following traditional specimen-based collecting and culturing surveys, but only after much more extensive sampling. The high rate at which new sequence types were recovered even after sampling 863 fungal ITS sequences and the dominance of fungi in our libraries relative to other eukaryotes suggest that the abundance and diversity of fungi in forest soils may be much higher than previously hypothesized. All sequences were deposited in GenBank, with accession numbers AY 969316 to AY 970290 for the ITS sequences and AY 969135 to AY 969315 for the SSU sequences.


Subject(s)
DNA, Ribosomal Spacer/analysis , Ecosystem , Fungi/classification , Sequence Analysis, DNA , Soil Microbiology , Computational Biology , Fungi/genetics , Genes, rRNA/genetics , Genetic Variation , Molecular Sequence Data , Phylogeny , Pinus taeda , Polymerase Chain Reaction , Trees
20.
Appl Environ Microbiol ; 71(7): 4117-20, 2005 Jul.
Article in English | MEDLINE | ID: mdl-16000830

ABSTRACT

Here we describe a quantitative PCR-based approach to estimating the relative abundances of major taxonomic groups of bacteria and fungi in soil. Primers were thoroughly tested for specificity, and the method was applied to three distinct soils. The technique provides a rapid and robust index of microbial community structure.


Subject(s)
Bacteria/classification , Ecosystem , Fungi/classification , Polymerase Chain Reaction/methods , Soil Microbiology , Bacteria/genetics , Bacteria/isolation & purification , DNA Primers , DNA, Bacterial/analysis , DNA, Fungal/analysis , Fungi/genetics , Fungi/isolation & purification , Sensitivity and Specificity , Species Specificity
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