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Recent studies have implemented a calculated additive toxicity (CAT) approach that sums measured disinfection byproduct (DBP) concentrations weighted by their respective in vitro bioassay potencies to estimate their associated risk in disinfected waters. In this study, the CAT approach was used to systematically investigate 21 regulated and unregulated DBPs measured in drinking water at the household level. Water samples from the tap were collected from over 120 randomly selected participants supplied by eight public water systems using four distinct source water types, two types of disinfection processes, and across two seasons. The purpose of this study was to compare CAT using multiple biological end points, examine household variability, identify DBPs driving toxicity, and assess if current regulated DBPs are adequate predictors of unregulated DBPs. Our results support the significance of unregulated DBPs, particularly haloacetonitriles and iodoacetic acid, as drivers of toxicity. Simple linear models between regulated versus unregulated concentrations and CAT were overall weak with 67% considered poor ( r 2 < 0.3). These results reveal that current regulatory monitoring approaches may not be adequately capturing true household exposure due to higher contribution of unregulated DBPs to CAT and poor predictability between regulated and unregulated DBP-mediated CAT., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.

White-nose syndrome (WNS) is a devastating disease of hibernating bats caused by the fungus Pseudogymnoascus destructans . We obtained 383 fungal and bacterial isolates from the Soudan Iron Mine, an important bat hibernaculum in Minnesota, then screened this library for antifungal activity to develop biological control treatments for WNS. An extract from the fungus Oidiodendron truncatum was subjected to bioassay-guided fractionation, which led to the isolation of 14 norditerpene and three anthraquinone metabolites. Ten of these compounds were previously described in the literature, and here we present the structures of seven new norditerpene analogues. Additionally, this is the first report of 4-chlorophyscion from a natural source, previously identified as a semisynthetic product. The compounds PR 1388 and LL-Z1271α were the only inhibitors of P. destructans (MIC = 7.5 and 15 μg/mL, respectively). Compounds were tested for cytotoxicity against fibroblast cell cultures obtained from Myotis septentrionalis (northern long eared bat) and M. grisescens (gray bat) using a standard MTT viability assay. The most active antifungal compound, PR 1388, was nontoxic toward cells from both bat species (IC 50 > 100 μM). We discuss the implications of these results in the context of the challenges and logistics of developing a substrate treatment or prophylactic for WNS.

Understanding how rising temperatures, ocean acidification, and hypoxia affect the performance of coastal fishes is essential to predicting species-specific responses to climate change. Although a population's habitat influences physiological performance, little work has explicitly examined the multi-stressor responses of species from habitats differing in natural variability. Here, clearnose skate (Rostaraja eglanteria) and summer flounder ( Paralichthys dentatus ) from mid-Atlantic estuaries, and thorny skate ( Amblyraja radiata ) from the Gulf of Maine, were acutely exposed to current and projected temperatures (20, 24, or 28 °C; 22 or 30 °C; and 9, 13, or 15 °C, respectively) and acidification conditions (pH 7.8 or 7.4). We tested metabolic rates and hypoxia tolerance using intermittent-flow respirometry. All three species exhibited increases in standard metabolic rate under an 8 °C temperature increase (Q 10 of 1.71, 1.07, and 2.56, respectively), although this was most pronounced in the thorny skate. At the lowest test temperature and under the low pH treatment, all three species exhibited significant increases in standard metabolic rate (44-105%; p < 0.05) and decreases in hypoxia tolerance (60-84% increases in critical oxygen pressure; p < 0.05). This study demonstrates the interactive effects of increasing temperature and changing ocean carbonate chemistry are species-specific, the implications of which should be considered within the context of habitat., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Nanopore sensing has enabled label-free single-molecule measurements on a wide variety of analytes, including DNA, RNA, and protein complexes. Much progress has been made toward biotechnological applications; however, electrically probing the ion current introduces nonideal noise components. Here we further develop a method to couple an ionic current to a photon-by-photon counting of fluorescent signal from Ca(2+)-sensitive dyes and demonstrate label-free optical detection of biopolymer translocation through solid-state nanopores using TIRF and confocal microscopy. We show that by fine adjustment of the CaCl2 gradient, EGTA concentration, and voltage, the optical signals can be localized to the immediate vicinity of the pore. Consequently, the noise spectral density distribution in the optical signal exhibits a nearly flat distribution throughout the entire frequency range. With the use of high-speed photon counting devices in confocal microscopy and higher photon count rates using stronger light sources, we can improve the signal-to-noise ratio of signal acquisition, while the use of wide-field imaging in TIRF can allow for simultaneous quantitative imaging of large arrays of nanopores.

Controlling DNA translocation speed is critically important for nanopore sequencing as free electrophoretic threading is far too rapid to resolve individual bases. A number of promising strategies have been explored in recent years, largely driven by the demands of next-generation sequencing. Engineering DNA-nanopore interactions (known to dominate translocation dynamics) with organic coatings is an attractive method as it does not require sample modification, processive enzymes, or complicated and expensive fabrication steps. In this work, we show for the first time 4-fold tuning of unfolded, single-file translocation time through small, amine-functionalized solid-state nanopores by varying the solution pH in situ. Additionally, we develop a simple analytical model based on electrostatic interactions to explain this effect which will be a useful tool in designing future devices and experiments.

Bacterial adhesion to and subsequent colonization of surfaces are the first steps toward forming biofilms, which are a major concern for implanted medical devices and in many diseases. It has generally been assumed that strong irreversible adhesion is a necessary step for biofilm formation. However, some bacteria, such as Escherichia coli when binding to mannosylated surfaces via the adhesive protein FimH, adhere weakly in a mode that allows them to roll across the surface. Since single-point mutations or even increased shear stress can switch this FimH-mediated adhesion to a strong stationary mode, the FimH system offers a unique opportunity to investigate the role of the strength of adhesion independently from the many other factors that may affect surface colonization. Here we compare levels of surface colonization by E. coli strains that differ in the strength of adhesion as a result of flow conditions or point mutations in FimH. We show that the weak rolling mode of surface adhesion can allow a more rapid spreading during growth on a surface in the presence of fluid flow. Indeed, an attempt to inhibit the adhesion of strongly adherent bacteria by blocking mannose receptors with a soluble inhibitor actually increased the rate of surface colonization by allowing the bacteria to roll. This work suggests that (i) a physiological advantage to the weak adhesion demonstrated by commensal variants of FimH bacteria may be to allow rapid surface colonization and (ii) antiadhesive therapies intended to prevent biofilm formation can have the unintended effect of enhancing the rate of surface colonization.

L-Phenylacetylcarbinol (L-PAC) is the precursor for L-ephedrine and D-pseudoephedrine, alkaloids possessing alpha- and beta-adrenergic activity. The most commonly used method for production of L-PAC is a biological method whereby the enzyme pyruvate decarboxylase (PDC) decarboxylates pyruvate and then condenses the product with added benzaldehyde. The process may be undertaken by either whole cells or purified PDC. If whole cells are used, the biomass may be grown and allowed to synthesize endogenous pyruvate, or the cells may be used as a catalyst only, with both pyruvate and benzaldehyde being added. Several yeast species have been investigated with regard to L-PAC-producing potential; the most commonly used organisms are strains of Saccharomyces cerevisiae and Candida utilis. It was found that initial high production rates did not necessarily result in the highest final yields. Researchers then examined ways of improving the productivity of the process. The substrate, benzaldehyde, and the product, L-PAC, as well as the by-products, were found to be toxic to the biomass. Methods examined to reduce toxicity include modification of benzaldehyde dosing regimes, immobilization of biomass or purified enzymes, modification of benzaldehyde solubility and the use of two-phase reaction systems. Various means of modifying metabolism to enhance enzyme activity, relevant metabolic pathways and yield have been examined. Methods investigated include the use of respiratory quotient to influence pyruvate production and induce fermentative activity, reduced aeration to increase PDC activity, and carbohydrate feeding to modify glycolytic enzyme activity. The effect of temperature on L-PAC yield has been examined to identify conditions which provide the optimal balance between L-PAC and benzyl alcohol production, and L-PAC inactivation. However, relatively little work has been undertaken on the effect of medium composition on L-PAC yield.

The theory and practice of a novel spectrophotometric method for the enzymatic determination of NAD+ and NADH is described. The method can not discriminate between NAD+ and NADH, but determines the concentration of the sum of both nucleotides. The method is based on the bleaching of p-nitroso-N,N-dimethylaniline (NMDA) (epsilon 440 nm = 35400 M-1cm-1) with NADH, in the presence of ethanol and yeast alcohol dehydrogenase, under the conditions of enzymatic cycling (ethanol > NDNA > NAD/H). The initial rates of -NDMA bleaching are proportional to the concentration of NAD+ or NADH, in a broad range from 10 nM to 100 microM.

The nucleotide sequence of cDNA from a high-passage, cell culture-adapted variant of hepatitis A virus strain HM175 was compared with the previously determined sequences of wild-type virus and two other cell culture-adapted variants. A total of 42 nucleotide changes were detected when the sequence was compared with wild-type virus. Five of these changes were common to all cell culture-adapted strains and a further two changes were shared by the strains that had experienced the greatest number of cell culture passages. The mutations were distributed throughout the genome coding for amino acid substitutions in regions 2B, 2C and 3D with silent changes in 1C and the 5' non-coding region. The possible relevance of these mutations to cell culture adaptation and attenuation is discussed.

Hepatitis A virus (HAV) strain HM-175 was passaged six times in marmosets, 59 times in cell culture and purified from infected cell culture supernatant fluid. The viral RNA was extracted, copied into cDNA and the cDNA:RNA hybrids were cloned into the PstI site of plasmid pBR322. The cDNA clones were authenticated by hybridization to RNA extracted from HAV-infected cells and clones representing the 3' end of the genome were identified using a previously authenticated cDNA clone. The clones represented all but 29 bases of the HAV genome. They were compared to HAV strain HM-175 cDNA cloned from viral RNA after three passages in marmosets on the basis of restriction endonuclease mapping and DNA sequencing. No differences were found in either the presence or absence of restriction endonuclease sites using 33 different restriction enzymes. Sequencing of cDNA representing bases 29 to 1002 of the HAV genome revealed eight base changes all of which were within the 5' noncoding region.

In a double-blind, randomized study the efficacy of Ro 15-1788 as a benzodiazepine antagonist was evaluated in patients anaesthetized with flunitrazepam. The effects were compared with a comparable group of patients who did not receive the antagonist. Ro 15-1788 significantly reversed the sedative and hypnotic effects of flunitrazepam and reduced the degree of anterograde amnesia. No side-effects were attributable to the drug.

Eosinophilia and jaundice occured in a depressed patient treated with amitriptyline, an association which is previously unreported. These complications cleared with withdrawal of the drug. This clinical picture should be added to the known hepatic complications of amitriptyline.

Nine strains of Campylobacter species other than Campylobacter jejuni, Campylobacter coli, and Campylobacter laridis were isolated from patients with acute diarrhea. All nine strains showed preferred growth at 37 degrees C under microaerophilic conditions. Conventional microbiological tests and DNA-DNA dot blotting were used to identify these strains. Three of the nine Campylobacter strains hydrolyzed hippurate, reduced nitrate, produced catalase, were resistant to cephalothin, and were shown to be highly related to C. jejuni type strains. Two strains had negative or weak catalase activity and were hippurate negative. Three other strains had characteristics similar to those of Campylobacter cinaedi. The ninth strain, isolated from a homosexual man with antibodies to human immunodeficiency virus (human T-cell lymphotropic virus type III), showed unique features different from those of all the known campylobacters used in this study. This strain grew well at 25 and 37 degrees C and was catalase and nitrate positive, hippurate negative, and resistant to cephalothin.

Forty-one strains of adenovirus type 19/37 (Ad19/37) mainly isolated from patients with keratoconjunctivitis or conjunctivitis between 1974 and 1984 were re-evaluated by serum neutralization (SN), haemagglutination inhibition (HI) and DNA restriction analysis. Of 19 isolates which were neutralized to high titre by antiserum prepared against prototype Ad19, 5 showed cross-reactivity with 32-64 units of Ad37 antiserum, while of 22 strains neutralized by high titre by Ad37 antiserum, 3 showed cross-reactivity with 32 units of Ad19 antiserum. By DNA restriction analysis, all Ad19 isolates were identical to each other and to Ad19A virus. Using endonuclease Bgl 1, three variants were observed among the Ad37 isolates.