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Summary RNA s (sRNA s) modulate key physiological mechanisms through post‐transcriptional and transcriptional silencing of gene expression. SmallRNA s fall into two major categories: those are reliant onRNA ‐dependentRNA polymerases (RDR RDR 12 /6 ‐dependentsRNA s include phased and repeat‐associated short interferingRNA s, while knownRDR 12 /6 ‐independentsRNA s are primarily microRNA s (miRNA ) and other hairpin‐derivedsRNA s. In this study we produced and analyzedsRNA ‐seq libraries fromrdr1 /rdr2 /rdr6 triple mutant plants. We found 58 previously annotated miRNA loci that were reliant onRDR 12 , or ‐6 function, casting doubt on their classification. We also found 38RDR 12 /6‐independentsRNA loci that are notMIRNA sRNA biogenesis. These 38sRNA ‐producing loci have as‐yet‐undescribed biogenesis mechanisms, and are frequently located in the vicinity of protein‐coding genes. Altogether, our analysis suggests that these 38 loci represent one or more undescribed types ofsRNA inArabidopsis thaliana . -
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Abstract Assessing the environmental factors that influence the ability of a threatened species to move through a landscape can be used to identify conservation actions that connect isolated populations. However, direct observations of species' movement are often limited, making the development of alternate approaches necessary. Here we use landscape genetic analyses to assess the impact of landscape features on the movement of individuals between local populations of a threatened snake, the eastern massasauga rattlesnake (
Sistrurus catenatus ). We linked connectivity data with habitat information from two landscapes of similar size: a large region of unfragmented habitat and a previously studied fragmented landscape consisting of isolated patches of habitat. We used this analysis to identify features of the landscape where modification or acquisition would enhance population connectivity in the fragmented region. We found evidence that current connectivity was impacted by both contemporary land‐cover features, especially roads, and inherent landscape features such as elevation. Next, we derived estimates of expected movement ability using a recently developed pedigree‐based approach and least‐cost paths through the unfragmented landscape. We then used our pedigree and resistance map to estimate resistance polygons of the potential extent forS. catenatus movement in the fragmented landscape. These polygons identify possible sites for future corridors connecting currently isolated populations in this landscape by linking the impact of future habitat modification or land acquisition to dispersal ability in this species. Overall, our study shows how modeling landscape resistance across differently fragmented landscapes can identify habitat features that affect contemporary movement in threatened species in fragmented landscapes and how this information can be used to guide mitigation actions whose goal is to connect isolated populations. -
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SUMMARY The red algal genus
Dudresnaya (Dumontiaceae, Gigartinales) has traditionally been a morphologically well‐defined taxon, but its molecular phylogeny has rarely been studied. To examine the phylogenetic relationships amongDudresnaya species, we generated new partial sequences of mitochondrialcox 1, chloroplastrbc L and nuclear 28S rRNA genes from an undescribedDudresnaya species from Okinawa Island, Japan, alongside five additional described species. Our phylogenetic analyses show thatDudresnaya is genetically diverse and polyphyletic. Based on molecular phylogeny and morphological data, we describe the OkinawanDudresnaya as a new species,Dudresnaya ryukyuensis , and transferredDudresnaya minima andDudresnaya littleri , which were phylogenetically and morphologically distinct from the genuineDudresnaya , to the new generaHimehibirhodia andNudresdaya , respectively. Our phylogenetic analyses also showed that the Dumontiaceae is not a monophyletic group including the Gainiaceae and Rhizophyllidaceae (DGR complex). Considering that the DGR complex exhibits female reproductive structures and their post‐fertilization development that are similar to each other, the DGR complex appears to be recognized as the Dumontiaceaesensu lato . -
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Abstract Patterns of
δ 18O andδ 2H in Earth's precipitation provide essential scientific data for use in hydrological, climatological, ecological and forensic research. Insufficient global spatial data coverage promulgated the use of gridded datasets employing geostatistical techniques (isoscapes) for spatiotemporally coherent isotope predictions. Cluster‐based isoscape regionalization combines the advantages of local or regional prediction calibrations into a global framework. Here we present a revision of a Regionalized Cluster‐Based Water Isotope Prediction model (RCWIP2) incorporating new isotope data having extensive spatial coverage and a wider array of predictor variables combined with high‐resolution gridded climatic data. We introduced coupling ofδ 18O andδ 2H (e.g.,d ‐excess constrained) in the model predictions to prevent runaway isoscapes when each isotope is modelled separately and cross‐checked observed versus modelledd ‐excess values. We improved model error quantification by adopting full uncertainty propagation in all calculations. RCWIP2 improved the RMSE over previous isoscape models by ca. 0.3 ‰ forδ 18O and 2.5 ‰ forδ 2H with an uncertainty <1.0 ‰ forδ 18O and < 8 ‰ forδ 2H for most regions of the world. The determination of the relative importance of each predictor variable in each ecoclimatic zone is a new approach to identify previously unrecognized climatic drivers on mean annual precipitationδ 18O andδ 2H. The improved RCWIP2 isoscape grids and maps (season, monthly, annual, regional) are available for download athttps://isotopehydrologynetwork.iaea.org . -
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Abstract Hemoglobin III (HbIII) is one of the two oxygen reactive hemoproteins present in the bivalve,
Lucina pectinata . The clam inhabits a sulfur‐rich environment and HbIII is the only hemoprotein present in the system which does not yet have a structure described elsewhere. It is known that HbIII exists as a heterodimer with hemoglobin II (HbII) to generate the stable Oxy(HbII‐HbIII) complex but it remains unknown if HbIII can form a homodimeric species. Here, a new chromatographic methodology to separate OxyHbIII from the HbII‐HbIII dimer has been developed, employing a fast performance liquid chromatography and ionic exchange chromatography column. The nature of OxyHbIII in solution at concentrations from 1.6 mg/mL to 20.4 mg/mL was studied using small angle X‐ray scattering (SAXS). The results show that at all concentrations, the Oxy(HbIII‐HbIII) dimer dominates in solution. However, as the concentration increases to nonphysiological values, 20.4 mg/mL, HbIII forms a 30% tetrameric fraction. Thus, there is a direct relationship between the Oxy(HbIII‐HbIII) oligomeric form and hemoglobin concentration. We suggest it is likely that the OxyHbIII dimer contributes to active oxygen transport in tissues ofL pectinata , where the Oxy(HbII‐HbIII) complex is not present.
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/1462-2920.15877
