Physico-chemical variables determining the invasion risk of freshwater habitats by alien mollusks and crustaceans

The aim of this study was to assess the invasion risk of freshwater habitats and determine the environmental variables that are most favorable for the establishment of alien amphipods, isopods, gastropods, and bivalves. A total of 981 sites located in streams and rivers in Germany. Therefore we analyzed presence-absence data of alien and indigenous amphipods, isopods, gastropods, and bivalves from 981 sites located in small to large rivers in Germany with regard to eight environmental variables: chloride, ammonium, nitrate, oxygen, orthophosphate, distance to the next navigable waterway, and maximum and minimum temperature. Degraded sites close to navigable waters were exposed to an increased invasion risk by all major groups of alien species. Moreover, invaded sites by all four groups of alien species were similar, whereas the sites where indigenous members of the four groups occurred were more variable. Increased temperature and chloride concentration as well as decreased oxygen concentration were identified as major factors for the invasibility of a site. Species-specific analyses showed that chloride was among the three most predictive environmental variables determining species assemblage in all four taxonomic groups. Also distance to the next navigable waterways was similarly important. Additionally, the minimum temperature was among the most important variables for amphipods, isopods, and bivalves. The bias in the occurrence patterns of alien species toward similarly degraded habitats suggests that the members of all four major groups of freshwater alien species are a non-random, more tolerant set of species. Their common tolerance to salinity, high temperature, and oxygen depletion may reflect that most alien species were spread in ballast water tanks, where strong selective pressures, particularly temperature fluctuations, oxygen depletion, and increased salinity may create a bottleneck for successful invasion. Knowledge on the major factors that influence the invasion risk of a habitat is needed to develop strategies to limit the spread of invasive species

Retinoid regulation of heparin-binding EGF-like growth factor gene expression in human keratinocytes and skin *

Retinoic acid (RA) has profound effects on epidermal homeostasis; however, the molecular mechanisms by which retinoids regulate keratinocyte cell proliferation and differentiation are not well understood. Here we report that mRNA expression of heparin-binding EGF-like growth factor (HB-EGF), a member of the EGF family of growth factors, is induced by RA in human keratinocytes and skin, and is overexpressed in the context of epidermal hyperplasia in vivo. Treatment of normal adult human keratinocytes with micromolar concentrations of RA significantly induced the expression of HB-EGF. The response was efficiently blocked by specific inhibitors of ErbB tyrosine kinase activity, MAP kinase kinase (MEK), or p38 stress-activated protein kinase. RA also enhanced the induction of HB-EGF mRNA in human skin organ culture, an ex vivo model system displaying many similarities to wound healing in vivo. HB- EGF transcripts were markedly increased in human skin by topical treat- ment with RA under conditions known to provoke epidermal hyperplasia. HB-EGF transcripts were also markedly overexpressed in the hyperplas- tic epidermis of psoriatic lesions, relative to normal skin. These results support the hypothesis that the effects of RA on epidermal hyperplasia are mediated at least in part by HB-EGF, and suggest that signal transduction mechanisms other than or in addition to nuclear RA receptors contribute to this effect.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72809/1/j.1600-0625.1998.tb00339.x.pd

Computational tools for the simulation and analysis of spin-polarized EPR spectra

The EPR spectra of paramagnetic species induced by photoexcitation typically exhibit enhanced absorptive and emissive features resulting from sublevel populations that differ from thermal equilibrium. The populations and the resulting spin polarization of the spectra are dictated by the selectivity of the photophysical process generating the observed state. Simulation of the spin-polarized EPR spectra is crucial in the characterization of both the dynamics of formation of the photoexcited state as well as its electronic and structural properties. EasySpin, the simulation toolbox for EPR spectroscopy, now includes extended support for the simulation of the EPR spectra of spin-polarized states of arbitrary spin multiplicity and formed by a variety of different mechanisms, including photoexcited triplet states populated by intersystem crossing, charge recombination or spin polarization transfer, spin-correlated radical pairs created by photoinduced electron transfer, triplet pairs formed by singlet fission and multiplet states arising from photoexcitation in systems containing chromophores and stable radicals. In this paper, we highlight EasySpin’s capabilities for the simulation of spin-polarized EPR spectra on the basis of illustrative examples from the literature in a variety of fields ranging across chemistry, biology, material science and quantum information science

Verhuellia is a segregate lineage in Piperaceae: more evidence from flower, fruit and pollen morphology, anatomy and development

Background and Aims The perianthless Piperales, i.e. Saururaceae and Piperaceae, have simple reduced flowers strikingly different from the other families of the order (e.g. Aristolochiaceae). Recent molecular phylogenies proved Verhuellia to be the first branch in Piperaceae, making it a promising object to study the detailed structure and development of the flowers. Based on recently collected material, the first detailed study since 1872 was conducted with respect to morphology, anatomy and development of the inflorescence, pollen ultrastructure and fruit anatomy. Methods Original Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Light Microscopy (LM) observations on Verhuellia lunaria were compared with Piperaceae, Saururaceae and fossils. Key results The inflorescence is an indeterminate spike with sessile flowers, each in the axil of a bract, developing in acropetal, helical succession. Flowers consist of two (occasionally three) stamens with basifixed tetrasporangiate anthers and latrorse dehiscence by a longitudinal slit. The gynoecium lacks a style but has three to four stigma branches and a single, basal orthotropous, and unitegmic ovule. The fruit is a drupe with large multicellular epidermal protuberances. The pollen is very small, inaperturate, and areolate with hemispherical microechinate exine elements. Conclusions Despite the superficial similarities with different genera of Piperaceae and Saururaceae, the segregate position of Verhuellia revealed by molecular phylogenetics is supported by morphological, developmental and anatomical data presented here. Unitegmic ovules and inaperturate pollen, which are synapomorphies for the genus Peperomia, are also present in Verhuellia

EPR Study of UV-irradiated Thymidine Microcrystals Supports Radical Intermediates in Spore Photoproduct Formation

Spore photoproduct is a thymidine dimer formed when bacterial endospore DNA is exposed to ultraviolet (UV) radiation. The mechanism of formation of this thymidine dimer has been proposed to proceed through a radical-pair intermediate. The intermediate forms when a methyl-group hydrogen atom of one thymidine nucleobase is transferred to the C6 position of an adjacent thymidine nucleobase, forming two species, the TCH2 and TH radicals, respectively. Using a series of thymidine isotopologues and electron paramagnetic resonance (EPR) spectroscopy, we show that microcrystals of thymidine exposed to UV radiation produce these two radical species. We observe three sources that donate the additional hydrogen at the C6 position of the TH radical. One of the three sources is the methyl group of another thymidine molecule in a significant fraction of the TH species. This lends support to the radical-pair intermediate proposed in the formation of spore photoproduct

Estimation of Health-State Utility Values and Factors Driving Health-Related Quality of Life in People Living with HIV and AIDS and Receiving cART in Germany: Baseline Analysis of a Cohort Study

HIV has become a chronic disease since widespread of combined antiretroviral therapy (cART). Understanding the influence of therapeutic and preventive interventions on health-related quality of life (HRQoL) of people living with HIV and AIDS (PLWHA) is important. Information about health state utilities and HRQoL in PLWHA after the introduction of cART is limited, especially in Germany. The study aims to estimate and describe health state utilities and HRQoL in PLWHA in Germany and explore the effects of patient characteristics, clinical and treatment factors. Utilities and HRQoL in PLWHA in Germany were measured with the generic EQ-5D-3L questionnaire. Health state utilities were calculated based on the EQ-5D descriptive system using the German EQ-5D-3L time trade-off (TTO) value set. HRQoL was calculated based on the EQ visual analogue scale (EQ-VAS). Extensive descriptive analyses were performed to represent utility values for different groups of the patients. Generalized linear models (GLMs) with beta-inflated distributions were used to determine patient characteristics and clinical factors that influence TTO utilities and VAS scores. 1056 PLWHA completed the EQ-5D-3L questionnaires at the beginning of the study. The mean TTO utility value is 0.912 (SD ± 0.154), and the mean VAS HRQoL is 84.32 (SD ± 18.55). “Anxiety/depression” and “pain/physical discomfort” are the most affected dimensions. A longer period of living with HIV, a lower CD4-cell count, having symptomatic HIV or AIDS and an increased number of changes in therapy are associated with decreased utilities and a lower probability of having HRQoL of perfect health. No significant effect of duration of regimen was found. Depression significantly decreases TTO utility values. Higher education, full-time employment and female gender are associated with higher utilities. The resulted EQ-VAS values for PLWHA in Germany are comparable with EQ-VAS estimates for the general population. The obtained estimates can be used as inputs for health economic evaluations of HIV-interventions. Addressing anxiety and depression may reduce the quality of life impairment in PLWHA. Impact of comorbidities needs further investigation. © 2021, The Author(s)

Intragenic deletion in the gene encoding L -gulonolactone oxidase causes vitamin C deficiency in pigs

The absence of L-ascorbic acid (L-AA, or AA) synthesis in scurvy-prone organisms, including humans, other primates, guinea pigs, and flying mammals, was traced to the lack of L-gulonolactone oxidase (GULO) activity. GULO is a microsomal enzyme that catalyzes the terminal step in the biosynthesis of L-AA. Clinical cases of scurvy were described in a family of Danish pigs. This trait is controlled by a single autosomal recessive allele designated od (osteogenic disorder). Here we demonstrate that the absence of GULO activity and the associated vitamin C deficiency in od/od pigs is due to the occurrence of a 4.2-kbp deletion in the GULO gene. This deletion includes 77 bp of exon VIII, 398 bp of intron 7 and 3.7 kbp of intron 8, which leads to a frame shift. The mutant protein is truncated to 356 amino acids, but only the first 236 amino acids are identical to the wild-type GULO protein. In addition, the od allele seems to be less expressed in deficient and heterozygous pigs compared with the normal allele in heterozygous and wild-type animals as determined by ribonuclease protection assay. We also developed a DNA-based test for the diagnosis of the deficient allele. However, we failed to identify the mutated allele in other pig population