Population genetic structure and evolutionary history of Psammochloa villosa (Trin.) Bor (Poaceae) revealed by AFLP marker

Psammochloa villosa is an ecologically important desert grass that occurs in the Inner Mongolian Plateau where it is frequently the dominant species and is involved in sand stabilization and wind breaking. We sought to generate a preliminary demographic framework for P. villosa to support the future studies of this species, its conservation, and sustainable utilization. To accomplish this, we characterized the genetic diversity and structure of 210 individuals from 43 natural populations of P. villosa using amplified fragment length polymorphism (AFLP) markers. We obtained 1,728 well‐defined amplified bands from eight pairs of primers, of which 1,654 bands (95.7%) were polymorphic. Results obtained from the AFLPs suggested effective alleles among populations of 1.32, a Nei''s standard genetic distance value of 0.206, a Shannon index of 0.332, a coefficient of gene differentiation (G _ST) of 0.469, and a gene flow parameter (Nm) of 0.576. All these values indicate that there is abundant genetic diversity in P. villosa, but limited gene flow. An analysis of molecular variance (AMOVA) showed that genetic variation mainly exists within populations (64.2%), and we found that the most genetically similar populations were often not geographically adjacent. Thus, this suggests that the mechanisms of gene flow are surprisingly complex in this species and may occur over long distances. In addition, we predicted the distribution dynamics of P. villosa based on the spatial distribution modeling and found that its range has contracted continuously since the last interglacial period. We speculate that dry, cold climates have been critical in determining the geographic distribution of P. villosa during the Quaternary period. Our study provides new insights into the population genetics and evolutionary history of P. villosa in the Inner Mongolian Plateau and provides a resource that can be used to design in situ conservation actions and prioritize sustainable utilization.     

Irreversible Renal Damage after Transient Renin-Angiotensin System Stimulation: Involvement of an AT1-Receptor Mediated Immune Response

Transient activation of the renin-angiotensin system (RAS) induces irreversible renal damage causing sustained elevation in blood pressure (BP) in Cyp1a1-Ren2 transgenic rats. In our current study we hypothesized that activation of the AT₁-receptor (AT₁R) leads to a T-cell response causing irreversible impairment of renal function and hypertension. Cyp1a1-Ren2 rats harbor a construct for activation of the RAS by indole-3-carbinol (I3C). Rats were fed a I3C diet between 4–8 weeks of age to induce hypertension. Next, I3C was withdrawn and rats were followed-up for another 12 weeks. Additional groups received losartan (20 mg/kg/day) or hydralazine (100 mg/kg/day) treatment between 4–8 weeks. Rats were placed for 24h in metabolic cages before determining BP at week 8, 12 and 20. At these ages, subsets of animals were sacrificed and the presence of kidney T-cell subpopulations was investigated by immunohistochemistry and molecular marker analysis. The development of sustained hypertension was completely prevented by losartan, whereas hydralazine only caused a partial decrease in BP. Markers of renal damage: KIM-1 and osteopontin were highly expressed in urine and kidney samples of I3C-treated rats, even until 20 weeks of age. Additionally, renal expression of regulatory-T cells (Tregs) was highly increased in I3C-treated rats, whereas the expression of T-helper 1 (Th1) cells demonstrated a strong decrease. Losartan prevented these effects completely, whereas hydralazine was unable to affect these changes. In young Cyp1a1-Ren2 rats AT₁R activation leads to induction of an immune response, causing a shift from Th1-cells to Tregs, contributing to the development of irreversible renal damage and hypertension.     

Contributions toward understanding the biodiversity of Passiflora in North America: Updates and a new combination from the Baja California Peninsula,Mexico and vicinity

The Baja California Peninsula and surrounding landmasses harbor an abundant flora in an otherwise harsh and arid environment. Of the many plant groups native to this peninsular and insular region, passionflowers (Passiflora, Passifloraceae) are represented by several conspicuous taxa that all belong to a single lineage, section Dysosmia. Basic questions remain regarding this group, particularly the taxonomic status among the Passiflora arida complex. Therefore, we investigated the claims of endemism, habitat characteristics, and taxon boundaries with in section Dysosmia in the Baja California region using extensive sampling of herbarium specimens and iNaturalist observations. We confirmed that only one of the native Passiflora taxa (P. fruticosa) was endemic to the Baja California Peninsula, with an additional taxon (P. palmeri) considered near‐endemic. Environmental data revealed significant distinctions between the habitats of many of the native taxa as well as within the P. arida complex, especially with respect to precipitation and temperature tolerances. Geometric morphometric analyses of leaf shape were largely not successful at separating taxa, indicating leaf shape may not be a good indicator of taxon identity in this particular group. Based on ecological differences and discrete macro‐ and micromorphological features, a varietal name is here synonymized and a new combination is proposed: Passiflora pentaschista.     

How to build an inducible cartilage-specific transgenic mouse

Transgenic mice are used to study the roles of specific proteins in an intact living system. Use of transgenic mice to study processes in cartilage, however, poses some challenges. First of all, many factors involved in cartilage homeostasis and disease are also crucial factors in embryogenesis. Therefore, meddling with these factors often leads to death before birth, and mice who do survive cannot be considered normal. The build-up of cartilage in these mice is altered, making it nearly impossible to truly interpret the role of a protein in adult cartilage function. An elegant way to overcome these limitations is to make transgenic mice time- and tissue-specific, thereby omitting side-effects in tissues other than cartilage and during embryology. This review discusses the potential building blocks for making an inducible cartilage-specific transgenic mouse. We review which promoters can be used to gain chondrocyte-specificity - all chondrocytes or a specific subset thereof - as well as different systems that can be used to enable inducibility of a transgene.     

A detailed study of leaf micromorphology and anatomy of New World Vitis L. subgenus Vitis within a phylogenetic and ecological framework reveals evolutionary convergence

We investigated leaf anatomy and micromorphology in the New World Vitis using light and scanning electron microscopy to understand the correlation of these traits to molecular phylogenetic relationships and environmental affinity. We observed traits known to differ among species of Vitis with importance in traditional taxonomy of Vitis: trichome type, stomata morphology, mesophyll organization, and midrib vascularization. We found that traits associated with water conductance and photosynthesis comprised the highest loadings of axis one of a principal components analysis (PCA) while traits related to gas exchange (i.e., the stomatal apparatus) had high loadings on axis two. Using the PCA, we identified seven clusters of species, which showed little correlation to recently reported molecular phylogenetic relationships. Moreover, analyses using Bayes Traits and Bayesian Binary Method revealed little to no phylogenetic signal in trait evolution. PCA axes one and two separated species occurring in dry southwestern North American habitats from those in mesic places. For example, a cluster of V. monticola and V. arizonica occurred adjacent to a cluster of V. californica and V. girdiana in ordination space, and the latter three species share key leaf anatomical traits. Nevertheless, among these, only V. arizonica and V. girdiana are closely related according to molecular phylogeny. Thus, the leaf micromorphological/anatomical traits of Vitis observed in this study are highly correlated with environment, but not phylogenetic relationships. We expect that trait similarities among distantly related species may result from evolutionary convergences, especially within xeric habitats of western North America.     

Origins of cultivars of Chrysanthemum—Evidence from the chloroplast genome and nuclear LFY gene

The origins of cultivated chrysanthemums have attracted considerable attention, but they remain poorly known. Here, we reconstructed the phylogeny of representative well‐known cultivars and wild species of the genus Chrysanthemum using chloroplast genomes and the nuclear LEAFY gene. Our results suggest that geographic and ecological factors may determine the opportunities for wild species to be involved in the origin of the cultivars. The wild species C. indicum, C. zawadskii, C. dichrum, C. nankingense, C. argyrophyllum, and C. vestitum were likely directly or indirectly involved as paternal species of most of the chrysanthemum cultivars examined in this study. Yet, the maternal species is supported to be a lineage of an extinct wild Chrysanthemum species and its subsequent cultivars, as all accessions of chrysanthemum cultivars sampled formed a strongly supported clade, distinct from all other species of Chrysanthemum in the plastome tree. Thus, the cultivated chrysanthemums originated from multiple hybridizations involving several paternal species rather than only two or a few wild species, with an extinct species and its subsequent cultivars serving as the maternal parents. This finding is consistent with Chrysanthemum having high rates of hybridization and gene flow, which has been demonstrated within previous studies; nevertheless, it is important to unravel the role of an extinct wild Chrysanthemum species as the ultimate maternal parent species for all the chrysanthemum cultivars. Our results also suggest that C. vestitum from Tianzhu and Funiu Mountains in Anhui and Henan Provinces of China represent two distinct cryptic species.     

Mitochondrial control-region sequences in two shorebird species, the turnstone and the dunlin, and their utility in population genetic studies

We determined the mitochondrial control-region sequences of five turnstones (Arenaria interpres) and three dunlins (Calidris alpina). Comparisons revealed that the central part (part II) is conserved relative to much more variable parts at the beginning (part I) and the end (part III). This pattern of sequence conservation is also found in the control regions of other vertebrates. The average sequence divergence between turnstone and dunlin was 21.8% for part I, 7.5% for part II, and 29.5% for part III. Within-species sequence divergence over the entire control region was much lower, at 0.9% for turnstones and 2.0% for dunlins. In both shorebird species, part III contains a repetitive sequence composed only of A and C nucleotides, which has not been found in the control regions of other birds. A survey of the part I sequences of 25 turnstones and 25 dunlins sampled around the world revealed that these species have very different population genetic structures. Dunlins are not only much more differentiated in their sequences but also have a strongly subdivided population genetic structure. Pleistocene vicariant events combined with strong natal philopatry and high mutation rates of the sequences are likely responsible for this population genetic subdivision. Conversely, part I sequences of turnstones are weakly differentiated and are geographically unstructured. We argue that this is not the result of global gene flow but that, instead turnstones have recently expanded from a refugial population that was bottlenecked.      

Increase in levels of microbiota recoverable from male and larval Myrmecia gulosa (Fabricius) (Hymenoptera: Formicidae) following segregation from worker ants

The segregation of laboratory maintained male and larval Myrmecia gulosa from workers resulted in increased levels of culturable microbiota. After 29 days, microbial levels recovered from segregated males and larvae were 27 and 126 times greater than from males and larvae not segregated from workers. These findings are consistent with the hypothesis that metapleural gland secretions, absent in larvae and males, are transferred from workers to larvae, and males contribute to the inhibition of cuticular microbiota.