Leaf-associated macroinvertebrate assemblage and leaf litter breakdown in headwater streams depend on local riparian vegetation.

Headwater streams harbor diverse macroinvertebrate communities and are hotspots for leaf litter breakdown. The process of leaf litter breakdown mediated by macroinvertebrates forms an important link between terrestrial and aquatic ecosystems. Yet, how the vegetation type in the local riparian zone influences leaf-associated macroinvertebrate assemblages and leaf litter breakdown rates is still not resolved. We investigated how leaf-associated macroinvertebrate assemblages and leaf litter fragmentation rates differ between forested and non-forested sites using experimental leaf litter bags in sixteen sites paired across eight headwater streams in Switzerland. Our results show that sensitive taxa of the invertebrate orders Ephemeroptera, Plecoptera and Trichoptera (EPT) and the functional group of shredders were strongly associated with forested sites with overall higher values of abundance, diversity, and biomass of EPTs in forested compared to non-forested sites. However, the importance of riparian vegetation differed between study regions, especially for shredders. Fragmentation rates, which are primarily the result of macroinvertebrate shredding, were on average three times higher in forested compared to non-forested sites. Our results demonstrate that not only the composition of the aquatic fauna but also the functioning of an essential ecosystem process depend on the vegetation type in the local riparian zone. Supplementary Information: The online version contains supplementary material available at 10.1007/s10750-022-05049-7.

Over forty years of lowland stream restoration: Lessons learned?

Stream restoration efforts have increased, but the success rate is still rather low. The underlying reasons for these unsuccessful restoration efforts remain inconclusive and need urgent clarification. Therefore, the aim of the present study was to evaluate over 40 years of stream restoration to fuel future perspectives. To this purpose we evaluated the influence of policy goals on stream restoration efforts, biophysical restoration objectives, restoration measures applied including the scale of application and monitoring efforts. Information was obtained from five stream restoration surveys that were held among the regional water authorities in the Netherlands over the last 40 years and from an analysis of the international scientific publications on stream restoration spanning the same time period. Our study showed that there was a considerable increase in stream restoration efforts, especially motivated by environmental legislation. However, proper monitoring of the effectiveness of the measures was often lacking. Furthermore, a mismatch between restoration goals and restoration measures was observed. Measures are still mainly focused on hydromorphological techniques, while biological goals remain underexposed and therefore need to be better targeted. Moreover, restoration practices occur mainly on small scales, despite the widely recognized relevance of tackling multiple stressors acting over large scales for stream ecosystem recovery. In order to increase the success rate of restoration projects, it is recommended to improve the design of the accompanying monitoring programmes, allowing to evaluate, over longer time periods, if the measures taken led to the desired results. Secondly, we advise to diagnose the dominant stressors and plan restoration measures at the appropriate scale of these stressors, generally the catchment scale.

Responses of macroinvertebrate communities to land use specific sediment food and habitat characteristics in lowland streams.

The input of land use specific organic matter into lowland streams may impact sediment characteristics in terms of food resources and habitat structure, resulting in differences in macroinvertebrate community composition. Therefore, we investigated to what extent land use specific sediment food and habitat characteristics structure macroinvertebrate communities. To this purpose linear multiple regression models were constructed, in which macroinvertebrate biotic indices were considered as response variables and sediment characteristics as predictor variables, analysed in 20 stream stretches running through five different land use types. Sediment characteristics and macroinvertebrate community composition were land use specific. The carbon/nitrogen (C/N) ratio, woody debris substrate cover and the origin of fatty acids influenced macroinvertebrate community composition. Shannon-Wiener diversity was better explained by fatty acids origin, such as in grassland streams, where a higher relative content of plant derived fatty acids related to a higher macroinvertebrate diversity. In cropland and wastewater treatment plant (WWTP) streams with a low C/N ratio and dominated by microbial derived fatty acids, higher abundances of Oligochaeta and Chironomus sp. were observed. Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness was positively related to woody debris substrate cover, which only occurred in forest streams. Hence, macroinvertebrate community composition was influenced by the origin of the organic material, being either allochthonous or autochthonous and when autochthonous being either autotrophic or heterotrophic. It is therefore concluded that sediment food and habitat characteristics are key ecological filters.

Relationship between office isolated systolic or diastolic hypertension and white-coat hypertension across the age spectrum: a home blood pressure study.

OBJECTIVE: The current study investigated the prevalence of white-coat hypertension (WCH) and white-coat uncontrolled hypertension (WUCH) throughout the age spectrum among individuals with office isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH) and systolic-diastolic hypertension (SDH) who were untreated or treated with antihypertensive medications, respectively. METHODS: We cross-sectionally evaluated 8809 untreated (42% males, 52.1 ±â€Š16.2 years) and 9136 treated (39% males, 59.7 ±â€Š14.5 years) individuals from two independent Brazilian populations who underwent home blood pressure monitoring. Participants were also categorized as younger (<40 years), intermediate (≥40 and <60 years) and older (≥60 years) age. RESULTS: Unadjusted and adjusted analyses showed that the frequency of WCH and WUCH was significantly greater (P < 0.05) in ISH and IDH than SDH at all age groups. Logistic regression analysis adjusted for sex, BMI and studied population showed that, compared with SDH, ISH had in average 4.1, 3.1 and 1.6-fold greater risk of WCH and 3.3, 3.6 and 2.0-fold greater risk of WUCH at younger, intermediate and older ages, whereas IDH had in average 2.3, 2.6 and 2.0-fold greater risk of WCH and 3.8, 3.2 and 3.8-fold greater risk of WUCH at younger, intermediate and older ages, respectively. CONCLUSION: ISH and IDH were associated with higher prevalence of WCH and WUCH than SDH across all age spectrum. In addition, treated and untreated ISH individuals with age less than 60 years and treated IDH individuals of all ages had the highest risk of having WCH phenotypes.

Isolation and Characterization of Muscle-Derived Stem Cells from Dystrophic Mouse Models.

The study of the population of muscle satellite cells (SC) is important to understand muscle regeneration and its involvement in the different dystrophic processes. We studied two dystrophic mouse models, Largemyd and Lama2dy2j/J, that show an intense and very similar pattern of muscle degeneration, but with differences in the expression of genes involved in the regeneration cascade. They are, therefore, interesting models to study possible differences in the mechanism of activation and action of satellite cells in the dystrophic muscle. The main objectives of this chapter are to describe the isolation and characterization of SC populations, evaluating the presence of myogenic and pluripotent stem cells markers in normal and dystrophic muscles.

Land use affects lowland stream ecosystems through dissolved oxygen regimes.

The aim of the present study was to assess the impact of surrounding land use on the structure and functioning of lowland stream ecosystems. To this end, five different land use types were selected (forest, extensive grassland, intensive grassland, cropland and wastewater treatment plant) each represented by four replicate streams, in which diel dissolved oxygen concentrations were recorded, sediment and water quality parameters were measured and macroinvertebrate community composition was determined. Chironomus sp., Oligochaeta and Gastropoda dominated the cropland and wastewater treatment plant (WWTP) streams, while Plecoptera and most Trichoptera only occurred in forest and extensive grassland streams. Forest streams communities were related to a high oxygen saturation, a high C/N ratio in the sediment and woody debris and coarse particulate organic matter (CPOM) substrate cover. Macroinvertebrate communities in cropland and WWTP streams were related to a low oxygen saturation in water and sediment and high concentrations of dissolved nitrogen, phosphorus and carbon. It is concluded that land use specific impacts on lowland streams are likely exerted via fine sediment accumulation in deposition zones, affecting oxygen regimes, sediment oxygen demand and stream metabolism, ultimately changing macroinvertebrate community composition. This study supports therefore the importance of including the catchment scale in ecological stream quality assessments, combining structural and functional endpoints.

Muscle satellite cells and impaired late stage regeneration in different murine models for muscular dystrophies.

Satellite cells (SCs) are the main muscle stem cells responsible for its regenerative capacity. In muscular dystrophies, however, a failure of the regenerative process results in muscle degeneration and weakness. To analyze the effect of different degrees of muscle degeneration in SCs behavior, we studied adult muscle of the dystrophic strains: DMDmdx, Largemyd, DMDmdx/Largemyd, with variable histopathological alterations. Similar results were observed in the dystrophic models, which maintained normal levels of PAX7 expression, retained the Pax7-positive SCs pool, and their proliferation capacity. Moreover, elevated expression of MYOG, an important myogenic factor, was also observed. The ability to form new fibers was verified by the presence of dMyHC positive regenerating fibers. However, those fibers had incomplete maturation characteristics, such as small and homogenous fiber caliber, which could contribute to their dysfunction. We concluded that dystrophic muscles, independently of their degeneration degree, retain their SCs pool with proliferating and regenerative capacities. Nonetheless, the maturation of these new fibers is incomplete and do not prevent muscle degeneration. Taken together, these results suggest that the improvement of late muscle regeneration should better contribute to therapeutic approaches.

Blood pressure cutoffs for white-coat and masked effects in a large population undergoing home blood pressure monitoring.

The values used to define the presence of white-coat or masked blood pressure (BP) effects are arbitrary. The aim of this study was to investigate the accuracy of several cutoff points based on the difference between office and home BP (ΔBP) values to detect white-coat uncontrolled (WUCH) and masked uncontrolled (MUCH) hypertension, which are phenotypes with adverse prognoses, in a large cohort of treated hypertensive patients. This multicenter cross-sectional study included 6,049 treated hypertensive patients (40% males, mean age 59.1 ± 14.4 years) who underwent office and home BP monitoring. We compared the sensitivity, specificity, area under curve (AUC), and positive (PPV) and negative (NPV) predictive values of several ΔBP cutoffs to detect WUCH and MUCH. The 15/9 mmHg cutoff, which reflects a 1.0 standard deviation of the ΔBP, showed the best AUC (0.783, 95% CI = 0.772-0.794) for the detection of WUCH, particularly in individuals with office grade 1 hypertension (AUC = 0.811, 95% CI = 0.793-0.829). The -1/-1 mmHg cutoff, which considers all individuals who had lower systolic or diastolic BP levels in the office than at home, had the highest AUC (0.822, 95% CI = 0.808-0.836) for the detection of MUCH. Both cutoff values also had the best performances for identifying all patients with higher and lower office-than-home BP grades. In conclusion, the 15/9 and -1/-1 mmHg cutoffs showed the best performance for the detection of treated hypertensive patients with WUCH and MUCH, respectively, and therefore might be markers of significant white-coat and masked effects and could be useful for identifying preferential targets for more routine home BP measures.

Sediment composition mediated land use effects on lowland streams ecosystems.

Despite the widely acknowledged connection between terrestrial and aquatic ecosystems, the contribution of runoff to the sediment composition in lowland stream deposition zones and the subsequent effects on benthic invertebrates remain poorly understood. The aim of this study was therefore to investigate the mechanisms by which runoff affects sediment composition and macroinvertebrates in deposition zones of lowland stream ecosystems. To this end, sediment from runoff and adjacent instream deposition zones from streams with different land use was chemically characterized and the biological effects were assessed at the species, community and ecosystem level. Runoff and deposition zone sediment composition as well as biological responses differed clearly between forest and agricultural streams. The stream deposition zone sediment C/N ratio reflected the respective runoff sediment composition. Deposition zones in the forest stream had a higher C/N ratio in comparison to the agricultural streams. Growth of Hyalella azteca and reproduction of Asellus aquaticus were higher on forest stream sediment, whereas chironomids and worms suffered less mortality on the agricultural sediments containing only natural food. The forest stream deposition zones showed higher values for indices indicative of biological integrity and had a lower sediment oxygen demand. We concluded that agricultural land use affects lowland stream ecosystem deposition zones at the species, community and ecosystem level via altered food quality (C/N ratio) and higher oxygen demand of the sediment.