Growth and division mode plasticity by cell density in marine-derived black yeasts

The diversity and ecological contribution of the fungus kingdom in the marine environment remain under-studied. A recent survey in the Atlantic (Woods Hole, MA, USA) brought to light the diversity and unique biological features of marine fungi. The study revealed that black yeast species undergo an unconventional cell division cycle, which has not been documented in conventional model yeast species such as Saccharomyces cerevisiae (budding yeast) and Schizosaccharomyces pombe (fission yeast). The prevalence of this unusual property is unknown. Inspired by the findings in Woods Hole, I collected and identified >50 marine fungi species across 40 genera from the ocean surface, sediment, and macroalgal surface in the Pacific (Sugashima, Toba, Japan). The Sugashima collection largely did not overlap with the Woods Hole collection and included several unidentifiable species, further illustrating the diversity of marine fungi. Three black yeast species were isolated, two of which were commonly found in Woods Hole (Aureobasidium pullulans, Hortaea werneckii). Surprisingly, I observed that their cell division mode was dependent on cell density, and the previously reported unconventional division mode was reproduced only at a certain cell density. For all three black yeast species, cells underwent filamentous growth with septations at low cell density and immediately formed buds at high cell density. At intermediate cell density, two black yeasts showed rod cells undergoing septation at the cell equator, in a manner similar to S. pombe. In contrast, all eight budding yeast species showed a consistent division pattern regardless of cell density. In five budding yeast species, the mother cell formed a single bud at a time at an apparently random site, similar to S. cerevisiae. The other three budding yeast species possessed a fixed budding site. This study illustrates the plastic nature of the growth/division mode of marine-derived black yeast.

It’s complicated…Environmental DNA as a predictor of trout and char abundance in streams

The potential to provide inferences about fish abundance from environmental (e)DNA samples has generated great interest. However, the accuracy of these abundance estimates is often low and variable across species and space. A plausible refinement is the use of common aquatic habitat monitoring data to account for attributes that influence eDNA dynamics. We therefore evaluated the relationships between eDNA concentration and abundance of bull trout (Salvelinus confluentus), westslope cutthroat trout (Oncorhynchus clarkii lewisi) and rainbow trout (O. mykiss) at 42 stream sites in the Intermountain West (USA and CAN) and tested if accounting for site-specific habitat attributes improved the accuracy of fish abundance estimates. eDNA concentrations were positively associated with fish abundance but these relationships varied by species and site and there was considerable variation unaccounted for. Random site-level differences explained much of this variation, but specific habitat attributes of those sites explained relatively small amounts of this variation. Our results underscore that either eDNA sampling or environmental characterization will require further refinement before eDNA can be used reliably to estimate fish abundance in streams.

Explaining the urban premium in Chinese cities and the role of place-based policies

This paper relies on the empirical framework introduced in Combes et al. (2012) to address the following main questions: (a) what are the relative contributions of agglomeration and selection forces expected to drive the urban productivity premium previously observed in Chinese cities, and (b) to what extent does the industrial parks and zones (IPZs) program, a popular place-based policy, simultaneously influence selection and agglomeration mechanisms? The main findings are as follows. First, both agglomeration and selection forces are observed in larger, denser Chinese cities, indicating that earlier studies that failed to take into account selection likely overestimate the effect of agglomeration economies. Second, after taking into account non-random site selection based on matching, the IPZs program intensifies both agglomeration and selection forces, although the results depend strongly on who administers the program. The empirical findings highlight a theoretical connection between state intervention and explaining the observed urban premium in a transitioning economy context.

Efficient space virtualization for the Hoshen–Kopelman algorithm

In this paper, the efficient space virtualisation for the Hoshen–Kopelman algorithm is presented. We observe minimal parallel overhead during computations, due to negligible communication costs. The proposed algorithm is applied for computation of random-site percolation thresholds for four dimensional simple cubic lattice with sites’ neighborhoods containing next–next–nearest neighbors (3NN). The obtained percolation thresholds are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], where 2NN and NN stand for next–nearest neighbors and nearest neighbors, respectively.

Numerical Simulation of Small Radius Polaron in a Chain with Random Perturbations

In a number of publications about biophysical experiments on the transfer of a charge to DNA, it is assumed that charge is transferred via a super-exchange mechanism at short distances of 2–3 nucleotide pairs, and in long fragments the charge forms a polaron that moves along the chain under the influence of temperature fluctuations. Using numerical simutation, we investigate the dynamics of a polaron of small radius in a homogeneous chain plaiced in constant electric field at a finite temperature. It is shown that there is no charge transfer by the polaron mechanism, i.e. there is no sequential movement of the polaron from site to site, in chains with parameter valuess corresponding to homogeneous adenine DNA fragments. The “polaron or delocalized state” check is based on the control of the average characteristics: the delocalization parameter, the position of the maximum probability, and the maximum modulus displacement. The dynamics of individual trajectories is also considered. Without electric field, there is a mode of switching between the states "stationary polaron – delocalized state", and a new polaron arises at a random site of the chain. In the chain placed in field with constant intensity, the averaged charge moves in the direction of the field, but the transfer occurs in a delocalized state.

Site specific assessments of burrow- and lentic-dwelling crayfish communities: A proposed sampling design

We conducted a study to investigate methods to assess crayfish populations typically found in low gradient, lentic, floodplain habitats in Missouri. We used a random site selection process that allowed us to capture all known species from this region of Missouri. We compared two sampling methods for primary burrowing crayfishes at our sampling sites: hook-and-line capture technique and burrow excavation. Adjacent standing water habitats at sites were also sampled using a timed search method. Hook-and-line capture success was substantially less than reported in the literature (0.7% versus 80%), while burrow excavation was higher than reported (64% versus 40.7%). We successfully captured six crayfish species using burrow excavation, whereas lentic timed search sampling captured nine species in adjacent standing waters at our sampling sites. Our results suggest that additional efforts sampling lentic habitats rather than additional time searching for and excavating burrows is more likely to capture total community richness. We found a seasonal influence on burrow occupancy surveys, as Julian day was positively correlated to finding active crayfish burrows. Crayfish capture in standing water was positively affected by soil temperature, and negatively correlated to Julian day.

Abstract 18360: Predictors of Physician Under-recognition of Angina in Outpatients With Stable Coronary Artery Disease

Background: Under-recognition of angina by physicians may result in under-treatment with revascularization or medications that could improve patients’ quality of life. Patient and physician characteristics associated with under-recognition have never been described. Methods: Outpatients with stable CAD in a 24-site US registry completed the Seattle Angina Questionnaire (SAQ) and their physicians independently quantified patients’ angina in the month prior to their clinic visit. Angina frequency was categorized as none, monthly, and daily/weekly. Among patients who reported angina, under-recognition was defined as the physician reporting a lower frequency of angina than the patient. A hierarchical (for site and physician) logistic model examined patient and physician factors associated with under-recognition of angina. Physician variability was assessed with a median odds ratio (MOR), which compares the likelihood of 1 physician at 1 random site under-recognizing angina vs. another physician at another site. Results: Among 1203 patients with stable CAD, 304 patients reported angina in the prior month, of whom 122 (40%) were under-recognized by their physician. Physicians were more likely to under-recognize the frequency of angina in patients with heart failure and among patients with less frequent angina (Figure). No other patient or physician factors were associated with under-recognition. There was significant variability across physicians (MOR 2.6), indicating that some physicians were better than others at recognizing angina. Conclusions: Under-recognition of angina is common in routine clinical practice and was largely unrelated to standard patient and physician characteristics. The large variation across physicians suggests that a more systematic approach is needed to assess angina from patients with CAD. The use of a validated tool, such as the SAQ, should be tested for improving angina recognition and outcomes.