Asynchronous multitrophic level regime shifts show resilience to lake browning

Lake browning is widespread due to increased supply of dissolved organic carbon under climate warming and nitrogen deposition. However, multitrophic level responses to lake browning are poorly understood. Our study aims to explore such responses across multitrophic levels based on sedimentary records of diatoms, chrysophyte stomatocysts and chironomids in a remote headwater lake in the Three Gorges Reservoir region, central China. Although all biotic proxies were analysed in the same core, the timing of shifts in chironomids (1886 ± 18 CE) preceded that in chrysophyte stomatocysts (∼1914 ± 10 CE) and diatoms (∼1941 ± 6 CE). Shifts in biotic communities were closely linked to rising temperature, δ15N depletion (a proxy for nitrogen deposition), δ13C enrichment (a proxy for littoral moss expansion), as well as biotic interactions, whereas the relative importance of the driving forces varied among the three biotic groups. Our results suggest that the zoobenthos grazing effect might be more important than bottom-up pathways in humic environments. Additionally, the coexistence of benthic, littoral and pelagic algae after the 1950s suggested that mixotrophic chrysophytes could reduce lake browning through heterotrophic processes and sustain the ecological equilibrium between littoral, pelagic and benthic productivity. Therefore, lake browning ecosystem regime shifts require analyses of multiple trophic levels. Our results suggest that heterotrophy may become more important in lake ecosystem carbon cycling with water brownification in Mulong Lake, as well as similar montane lakes.

Obesity is associated with increased level of kisspeptin in mothers' blood and umbilical cord blood - a pilot study

OBJECTIVE

Kisspeptin (KP) is a major regulator of reproductive functions. It has also been shown to be involved in the metabolic changes associated with obesity. According to the well-established concept of prenatal programming, environmental factors can influence physiological and behavioral systems at the early stages of development. Thus, we hypothesized that in pregnant women, obesity can be associated with alterations in the levels of KP. We also assumed that the observed changes in obese mothers' blood (MB) would be reflected in the umbilical cord blood (CB).

MATERIALS AND METHODS

We collected MB and CB from obese and nonobese women and analyzed the differences in metabolic and hormonal profiles, including KP concentration, using commercially available assays.

RESULTS

We found that the level of KP was increased in the MB and CB of obese patients compared to nonobese subjects (p<0.05). A strong correlation was observed between the concentration of KP in MB and CB (r=0.8343; p<0.01). Moreover, we detected that the differences in the adipokine profile observed in the MB were not reflected in CB.

CONCLUSIONS

Our results indicate that blood KP concentration can serve as a valuable marker in pregnant women. However, further studies are needed to understand the alterations of this peptide in obese pregnant woman and their potential effects on offspring.

Effects of a nine-strain bacterial synbiotic compared to simethicone in colicky babies - an open-label randomised study

The aim of the study was to determine effects of administration of simethicone and a multi-strain synbiotic on the crying behaviour of colicky babies. The study design consisted of an open-label, two parallel treatment group study involving 87 infants aged 3-6 weeks with infantile colic (defined as crying episodes lasting 3 or more hours per day and occurring at least 3 days per week within 3 weeks prior to enrolment) randomly, unequally [1:1.5] assigned to receive simethicone (n=33) or a multi-strain synbiotic (n=54) orally for 4 weeks. The multi-strain synbiotic contained Lactobacillus acidophilus LA-14, Lacticaseibacillus casei R0215, Lacticaseibacillus paracasei Lp-115, Lacticaseibacillus rhamnosus GG, Ligilactobacillus salivarius Ls-33, Bifidobacterium lactis Bl-04, Bifidobacterium bifidum R0071, Bifidobacterium longum R0175 and fructooligosaccharides). Primary outcome measures were the responder rates (effect ≥50% reduction from baseline) of the measures 'crying days last 3 weeks', 'average evening crying duration last 3 weeks' and 'reduction of average number of crying phases per day last three weeks' at the end of treatment. The study is registered at ClinicalTrials.gov under NCT04487834. Significantly higher responder rates (effect ≥50% reduction from baseline) of the multi-strain synbiotic compared to simethicone were found for the measures 'crying days last 3 weeks' (72% vs 18%, P<0.0001) and 'average evening crying duration last 3 weeks' (85% vs 39%, P=0.0001). No significant difference was found for the measure 'reduction of average number of crying phases per day last three weeks' (50% vs 42%, P=0.4852). No adverse effects were reported for the two treatment groups. Based on these results, the multi-strain synbiotic can be considered as an interesting therapeutic possibility for the treatment of infantile colic, worthwhile to be investigated further in non-clinical and clinical studies.

Integrative Approach Helps Clarify Confusing Taxonomy of the Pseudopediastrum boryanum Species Complex (Chlorophyceae), Including Recognition of five Distinct Species

Sixteen monoclonal strains classified into six morphotypes typical of, or close to, intraspecific taxa of Pseudopediastum boryanum, including P. alternans (ALT), P. boryanum var. boryanum (BOR), P. boryanum var. cornutum (COR), P. boryanum var. forcipatum (FOR), P. boryanum var. longicorne (LON), and P. boryanum var. perforatum (PER), were simultaneously subjected to phylogenetic (26S rDNA and rbcL cpDNA) and morphometric analyses. Marginal cell shape, coenobium and cell size, and granule density on the cell surface were analyzed statistically. The shapes of some morphotypes (BOR, COR, FOR, and PER) were also compared to the shapes of corresponding type illustrations. Pseudopediastrum boryanum var. boryanum, without any reliable morphological and phylogenetic data, appeared to be a questionable taxon that needs a neotype. The variety longicorne proved to be a complex taxon that should be split after morphometric data of more strains and of the corresponding lectotype are included in the statistical analysis. A new species, Pseudopediastrum oblongum, was described, and four varieties were elevated to the species level, which resulted in establishing new combinations, P. cornutum, P. forcipatum, P. perforatum, and P. subgranulatum. Reference sequences for the new species and combinations were obtained. The paleoecological value of P. boryanum sensu lato appeared to be limited by the relatively low percentage of marginal cells typical of particular varieties and a high risk of their misidentification in the light microscope. The shape of marginal cells seemed to be the best diagnostic feature. Granule density could be helpful to discriminate between certain taxa.

Assessing morphological congruence in Dinobryon species and their stomatocysts, including a newly established Dinobryon pediforme-stomatocyst connection

The chrysophyte genus Dinobryon Ehrenberg consists of 44 taxa, which occur in freshwaters, rarely marine waters, mostly in temperate regions of the world. The taxa of Dinobryon produce characteristic solitary or dendroid colonies and resting stages called stomatocysts. Only 20 Dinobryon taxa have information on produced stomatocysts and only four stomatocysts are reliably linked with vegetative stages using modern identification standards employing scanning electron microscopy (SEM) analyses. In this study, an encysted material of Dinobryon pediforme (Lemmermann) Steinecke was collected in two lakes in contrasting regions of Poland. Light microscopy (LM) and scanning electron microscopy (SEM) analyses revealed that Dinobryon pediforme produces stomatocyst #61, Piątek J. that is described here as new morphotype following the International Statospore Working Group (ISWG) guidelines. This raises to five the number of reliable links between vegetative stages of Dinobryon species and corresponding stomatocysts. Phenotypic similarities between Dinobryon species and their stomatocysts, analysed for five reliably established links, showed no relationships in size and shape between loricas and stomatocysts belonging to the same species. The morphological characters of loricas and stomatocysts mapped onto the phylogenetic tree of the five Dinobryon species revealed only little congruence between their morphology and phylogenetic relationships.

Dismantling a complex of anther smuts (Microbotryum) on carnivorous plants in the genus Pinguicula

The anther smuts of the genus Microbotryum are known from host plant species belonging to the Caryophyllaceae, Dipsacaceae, Lamiaceae, Lentibulariaceae, Montiaceae, and Primulaceae. Of these, the anther smuts on Caryophyllaceae, in particular on Silene spp., are best known because they include model organisms studied in many disciplines of fungal biology. For Microbotryum species parasitic on Caryophyllaceae, a high degree of host specificity was revealed and several cryptic species were described. In contrast, the host specificity within Microbotryum pinguiculae occurring in anthers of different Pinguicula species (Lentibulariaceae) has not been investigated in detail until now. The anther smuts on Pinguicula alpina, P. villosa, and P. vulgaris, on which M. pinguiculae was described, were analyzed using nuc rDNA ITS1-5.8S-ITS2 and nuc rDNA 28S D1-D2 sequences and morphology to determine if they belong to one polyphagous species or rather represent three host-specific species. The results of the morphological investigations revealed no decisive differences between the anther smuts on different Pinguicula species. However, genetic divergence and molecular phylogenetic analyses, which split the specimens according to host plant species, supported host specificity of the anther smuts on different Pinguicula species. Accordingly, in addition to Microbotryum pinguiculae s. str. on Pinguicula vulgaris, M. alpinum sp. nov. on P. alpina from Europe and M. liroi sp. nov. on P. villosa from Asia are described and illustrated.

Dielectric properties of hypothermic rat artery

The temperature and frequency dependencies of the dielectric parameters for the rat artery are used to analyse effects of hypothermia on this tissue. Measurements were performed over the frequency range 500 Hz to 100 kHz and at temperatures from 19 to 60°C. The artery samples contained about 12% water by mass at room temperature at a relative humidity of 70%. The frequency dependencies of the loss tangent for the control, mild hypothermic and moderate hypothermic artery exhibit two peaks at 2 kHz and 35 kHz in the α-dispersion region. The results were discussed in terms of the distribution of relaxation frequencies and the activation energy for the conduction and polarization mechanisms particularly in the elastin-water and collagen-water systems. The knowledge about dielectric behavior of the hypothermic rat artery in vitro is important due to clinical application of local and systemic hypothermia.