Sexually dimorphic phenotypes are consequential to animal survival, and this is especially apparent with defense phenotypes. Amphibians have poison glands, and several lineages maintain a neurotoxin, tetrodotoxin (TTX), which is largely considered a derived chemical defense trait. However, production pathways are unclear, and, as such, whether males and females differentially produce or appropriate toxin concentrations is not known. We evaluated the relationship between TTX concentrations, sex, and morphology by collecting trait data from more than 850 wild newts of the genus Taricha and tested for sex-based differences, potential sex-based changes to the phenotype between breeding seasons, and factors influencing toxicity. Females, regardless of reproductive status, exhibited greater concentrations than males, and temporal patterns indicate male and female trait values tend to fluctuate concordantly at short time scales, with females showing greater change over time. Tree regression results underscored the importance of size and sex to the phenotype. Sexual dimorphism and plasticity of toxins broaden the ecological roles of animal poisons beyond defense only and should recast how we model the evolution of tetrodotoxin.

Intestinal microbiota, diet, and physical activity are inextricably linked to inflammation occurring in the presence of tumor progression and declining neurocognition. This study aimed to explore how fecal microbiota, inflammatory biomarkers, and neurocognitive behavior are influenced by voluntary exercise and surplus dietary protein and folic acid which are common health choices. Dietary treatments provided over 8 weeks to C57BL/CJ male mice (N = 76) were: Folic Acid (FA) Protein (P) Control (FPC, 17.9% P; 2 mgFA/kg); Folic Acid Deficient (FAD); Folic Acid Supplemented (FAS; 8 mgFA/kg); Low Protein Diet (LPD, 6% P); and High Protein Diet (HPD, 48% P). FAS mice had decreased plasma HCys (p < 0.05), therefore confirming consumption of FA. Objectives included examining influence of exercise using Voluntary Wheel Running (VWR) upon fecal microbiota, inflammatory biomarkers C - reactive protein (CRP), Vascular Endothelial Growth Factor (VEGF), Interleukin-6 (IL-6), nuclear factor kappa ß subunit (NF-κßp65), Caspase-3 (CASP3), Tumor Necrosis Factor-alpha (TNF-α), and neurocognitive behavior. CRP remained stable, while a significant exercise and dietary effect was notable with decreased VEGF (p < 0.05) and increased CASP3 (p < 0.05) for exercised HPD mice. Consumption of FAS did significantly increase (p < 0.05) muscle TNF-α and the ability to build a nest (p < 0.05) was significantly decreased for both FAD and LPD exercised mice. Rearing behavior was significantly increased (p < 0.05) in mice fed HPD. An emerging pattern with increased dietary protein intake revealed more distance explored in Open Field Testing. At week 1, both weighted and unweighted UniFrac principal coordinates analysis yielded significant clustering (permanova, p ≤ 0.05) associated with the specific diets. Consumption of a HPD diet resulted in the most distinct fecal microbiota composition. At the phylum level–comparing week 1 to week 8–we report a general increase in the Firmicutes/Bacteroidetes ratio, characterized by an outgrowth of Firmicutes by week 8 in all groups except the HPD. MaAsLin2 analysis corroborates this finding and emphasizes an apparent inversion of the microbiome composition at week 8 after HPD. Explicit modification of oncogenic inflammatory biomarkers and fecal microbiome post high FA and protein intake along with voluntary exercise contributed to current underlying evidence that this diet and exercise relationship has broader effects on human health and disease–perhaps importantly as a practical modulation of cancer progression and declining neurocognition.

[Cp*IrCl2]2 is a common precursor used to synthesize a large family of organometallic catalysts. While [Cp*IrCl2]2 is commercially available, dimers featuring other halides are not, although they can be accessed through [Cp*IrCl2]2. Published synthetic methods for the preparation of these halide dimers are time consuming, requiring reflux for 48 h. We have developed a new synthetic approach utilizing microwave-assisted synthesis (MAS) that significantly decreases the time required to prepare [Cp*IrX2]2 (X = Cl, Br, I). Reagents were heated beyond their normal boiling point in sealed reactors for 15 min at 120 C and products were isolated using traditional methods with yields comparable or exceeding literature methods. [Cp*IrX2]2 dimers synthesized using MAS were characterized by NMR spectroscopy, UV-Visible spectroscopy, and elemental analysis. These dimers were then used to synthesize a series of mononuclear iridium bipyridyl complexes, [Cp*Ir(bpy)X]X. This series of complexes was explored spectroscopically and electrochemically to identify potential electrocatalysts for future studies.

The Schiff base condensation of 8-aminoquinoline with 2-acetylcyclopentanone yielded two regioisomeric beta-ketoimines with a cyclopentanyl ring in the ketoimine backbone and a pendant quinolyl moiety. The major ketoimine, isolated in 64% yield, showed quinolyl addition to the cyclopentanyl ring, and it was characterized spectroscopically and crystallographically. This ketoimine was utilized to prepare a series of bis-ligated homoleptic magnesium, aluminum, and zinc complexes in 78-96% yield as well as aluminum and zinc ketoiminate phenoxide complexes in 68 and 66% yield, respectively. The five complexes were characterized spectroscopically and crystallographically, and the bis-ligated complexes showed distorted octahedral geometries. The aluminum phenoxide complex showed a monomeric, five-coordinate metal center (tau(5) = 0.83) while the zinc phenoxide complex displayed a dimeric structure with two five-coordinate zinc centers (tau(5) = 0.39 and 0.53) with bridging phenoxide and ketoiminate ligands, where idealized trigonal bipyramidal geometry tau(5) = 0.00 and idealized square pyramidal tau(5) = 1.00. The zinc phenoxide showed unexpected fluxional bonding character which was explored with VT-NMR from 220 to 325 K and is proposed to be dimer disproportionation to monomeric zinc complexes. Density Functional Theory (DFT) and Time-Dependent DFT calculations were used to investigate the regioisomeric ratio of the ketoimines and map the electronic structures for the ketoimines and complexes, providing insight into the nature of the observed electronic transitions.

Toxin evolution in animals is one of the most fascinating and complex subjects of scientific inquiry today. Gaining an understanding of toxins poses a multifaceted challenge given the diverse modes of acquisition, evolutionary adaptations, and abiotic components that affect toxin phenotypes. Here, we highlight some of the main genetic and ecological factors that influence toxin evolution and discuss the role of antagonistic interactions and coevolutionary dynamics in shaping the direction and extent of toxicity and resistance in animals. We focus on toxic Pacific newts (family Salamandridae, genus Taricha) as a system to investigate and better evaluate the widely distributed toxin they possess, tetrodotoxin (TTX), and the hypothesized model of arms-race coevolution with snake predators that is used to explain phenotypic patterns of newt toxicity. Finally, we propose an alternative coevolutionary model that incorporates TTX-producing bacteria and draws from an elicitor-receptor concept to explain TTX evolution and ecology.

Homocysteine, cysteine, cysteinyl-glycine, and glutathione are significant biological aminothiols (ATs) that are marker-molecules in Down syndrome, Alzheimer's disease, or have been implicated as risk factors in atherosclerosis and other vascular diseases, and therefore rapid determination of these molecules is desirable. After reduction of the disulfides, a widely used method utilizes derivatization with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonate (SBD-F) as a fluorogenic probe prior to reversed-phase HPLC separation followed by fluorescence detection. The traditional HPLC determination of ATs is time consuming and economically expensive. We have developed an ion-pair HPLC method coupled with indirect fluorescence detection after post-column reaction with a 2,4-dinitrobenzenesulfonate derivative of a 3-hydroxyflavone. The accuracy, precision, post-column temperature and residence time, and limit-of-detection were evaluated. Sample throughput and reduced sample preparation time of over an hour for the existing methods to less than 20 minutes for the new method is also demonstrated. No statistical differences in HCy, Cys, or Cys-Gly determinations in plasma samples were observed between our method and the traditional HPLC method.

Three ketoimines with pendant quinolyl moieties and a series of five-coordinate ketoiminate aluminum complexes were prepared and characterized spectroscopically and crystallographically. The synthesis of the ketoimines completed a series of ten regioisomers for which the product ratio varied between the product resulting from quinoline addition adjacent to the alkyl/aryl group or adjacent to the trifluoromethyl substituent. Quantitation of the ketoimine regioisomer ratios with F-19 NMR demonstrated the role of steric encumbrance in the nucleophilic attack mechanistic step of the Schiff base condensation reaction and was further supported by linear free energy relationships with the Charton steric parameter and DFT calculations. Eight five-coordinate aluminum complexes were prepared in 57-92% yield from ketoimines and tris(2,6-dimethylphenoxide) aluminum dimer and characterized with H-1, C-13, F-19, and Al-27 nuclear magnetic resonance spectroscopy, UV-visible absorbance spectroscopy, elemental analysis, and single-crystal X-ray crystallography. These mononuclear complexes differ from previously reported aluminum ion-pair complexes due to the symmetric cleavage of tris-dimethylphenoxide aluminum dimer by THF and were shown to have distorted trigonal bipyramidal coordination geometries (tau(5) = 0.73-0.89). In a preliminary study, the aluminum complexes were demonstrated to be effective initiators for ring-opening polymerization of epsilon-caprolactone (epsilon CL) to poly-caprolactone (PCL) and L-lactide (LA) to poly-lactic acid (PLA), reaching 77-99% conversion in 2 h for epsilon CL and 10 h for LA at 100 degrees C. (C) 2021 Elsevier Ltd. All rights reserved.

ABSTRACTSeven magnesium complexes (1–7) were synthesized by reaction of new (L 3‐H–L 5‐H) and previously reported ketoimine pro‐ligands with dibutyl magnesium and were isolated in 59–70% yields. Complexes 1–7 were characterized fully and consisted of bis‐ligated homoleptic ketoiminates coordinated in distorted octahedral geometry around the magnesium centers. The complexes were investigated for their ability to initiate the ring opening polymerization (ROP) of l‐lactide (L‐LA) to poly‐lactic acid (PLA) and ɛ‐caprolactone (ɛCL) to poly‐caprolactone in the presence of 4‐fluorophenol co‐catalyst. For L‐LA polymerization, complexes containing ligand electron‐donating groups (1–5) achieved >90% conversion in 2 h at 100 °C, while the presence of CF3 groups in 6 and 7 slowed or resulted in no PLA detected. With ɛCL, ROP initiated with 1–7 resulted in lower percentage conversion with similar electronic effects. Moderate molecular weight PLA polymeric material (14.3–21.3 kDa) with low polydispersity index values (1.23–1.56) was obtained, and ROP appeared to be living in nature. Copolymerization of L‐LA and ɛCL yielded block copolymers only from the sequential polymerization of ɛCL followed by L‐LA and not the reverse sequence of monomers or the simultaneous presence of both monomers. Polymers and copolymers were characterized with NMR, gel permeation chromatography, and differential scanning calorimetry. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 48–59

Seven aluminum ion-pair complexes (1-7) were synthesized by reaction of NNO Schiff base ketoimines with differing substituents with tris(2,6-dimethylphenoxy) aluminum dimer in an inert atmosphere glovebox at room temperature. The complexes were characterized with H-1, C-13, and F-19 nuclear magnetic resonance spectroscopy, absorbance spectroscopy, and elemental analysis. Furthermore, the dinuclear nature of the complexes was elucidated with single crystal X-ray crystallography and (27)AI NMR. The ion-pair complexes consisted of a bis-ligating homoleptic ketoiminate with octahedral coordination as an aluminum cation complex and a tetrahedral aluminum anion complex of 2,6-dimethylphenoxide. Each ion-pair was used to initiate the ring opening polymerization (ROP) of L- and rac-lactide to poly-lactic acid (PLA) in toluene at 100 degrees C at a 100:1 [LA]:[ion-pair] ratio. Proton NMR spectra showed percentage conversions of monomer to polymer of 96-99% in 18 h. The isolated polymeric materials were determined to have moderate molecular weights with low to moderate polydispersity index values using gel permeation chromatography. The bis-ligated aluminum cation and tetraphenoxide aluminate anions of 1 were isolated into separate compounds (8 and 9) with unreactive counter ions, and each yielded low molecular weight PLA under the polymerization conditions. Thus, lactide polymerization appeared to require both ion-pair components to yield the moderately high molecular weight PLA, and this was investigated spectroscopically. (C) 2018 Elsevier Ltd. All rights reserved.

Inducible phenotypic responses to environmental variation are ubiquitous across the tree of life, but it remains an open question whether amphibian chemical defense phenotypes are inducible. Tetrodotoxin (TTX) is a key chemical defense trait in North American and Eurasian newts (Salamandridae). We tested if TTX can be induced by exposing populations of adult and larval California newts (Taricha torosa) to sustained stressful conditions while longitudinally quantifying TTX concentrations. Adult newts rapidly increased chemical defenses in response to simulated predator attacks and consistently maintained elevated TTX concentrations relative to wild, non-captive individuals. We also found that laboratoryreared larvae maintained chemical defenses nearly three-fold greater than those of siblings reared in streams. Collectively, our results indicate that amphibian chemical defenses are not fixed. Instead, toxins are maintained at a baseline concentration that can quickly be increased in response to perceived risk with substantial increases to toxicity. Therefore, it is crucial that inducible variation be accounted for when considering ecological dynamics of chemically defended animals and coevolutionary predatorprey and mimic-model relationships.

Behaviours that influence habitat selection strongly determine species movement patterns. One component of animal behaviour that largely influences movement patterns and habitat choice is site fidelity. California newts (family Salamandridae) demonstrate remarkable site fidelity, typically homing to the same pool of a stream each breeding season. Individuals often occupy a specific pool throughout the breeding season, but some males shift among breeding pools, altering their set of potential mates, competitors, and predators. In this study, we measured dermal concentrations of the chemical defence compound tetrodotoxin (TTX) in recaptured male California newts ( Taricha torosa ) over five breeding seasons to evaluate whether relative TTX concentrations are associated with breeding site fidelity in the field. Our five years of field sampling indicates that TTX concentrations of individuals and group means fluctuate tremendously, implying that TTX is not a stable phenotypic trait. Despite such fluctuations, we found that an individual's relative TTX concentration explains fidelity to a breeding pool and suggests that newts may be able to assess both their own concentrations of TTX and that of conspecifics to make decisions about remaining in or abandoning a breeding pool. These results provide us a novel dimension to chemical defence phenotypes in nature and their ecological consequences, potentially requiring a re-evaluation of the coevolutionary dynamics of predation pressure on toxin-laden organisms.

In the last several decades, obesity rates have reached epidemic proportions, and increases the risk for a host of comorbidities, including diabetes, cardiovascular disease, and certain kinds of cancers. Boba milk tea, first became popular in the 1990s throughout Asia, and has gained more popularity in the United States and in Europe since 2000. Currently, available nutrition data from online sites suggest this beverage contains high amounts of sugar and fat. One published nutrition study suggests that boba tea drinks are part of the larger group of sugar-sweetened beverages (SSB) because these beverages are usually sweetened with high-fructose corn syrup (HFCS). This study experimentally determined the sugar composition (sucrose, fructose, glucose, and melezitose) and calorific values of boba milk tea drinks and their components. Results suggested that boba drinks fit the US Dietary Guidelines definition of a SSB. One 16-ounce boba drink exceeds the upper limit of added sugar intake recommended by the 2015 US Dietary Guidelines Advisory Committee. The high caloric and sugar content of boba beverages pose public health concerns as they have the potential to further exacerbate the childhood obesity epidemic. Nutrition education targeting Asian populations should give special attention to boba tea as a SSB. Also, prudent public health recommendations should be suggested for moderate consumption of these beverages. With the growing popularity of boba beverages in the United States, the findings from this study provide public health practitioners with valuable data on how boba beverages compare with other SSBs.

Eight bis-ligated, homoleptic, zinc complexes were synthesized through the reaction of NNO Schiff base ketoimines bearing varying substituents with diethyl zinc in an inert atmosphere glovebox at room temperature and isolated in 62-95% yield. The complexes were characterized with (1)H, (13)C, and (19)F nuclear magnetic resonance spectroscopy, absorbance spectroscopy, high resolution mass spectrometry, elemental analysis, and single crystal X-ray crystallography. The complexes were shown to adopt distorted octahedral coordination geometry around zinc. The (1)H and (19)F NMR spectra of complexes 1-7 showed stable zinc coordination at 300 K while the effect of steric encumbrance and two trifluoromethyl groups in complex 8 was investigated with variable temperature NMR. The bis-ligated zinc complexes were effective initiators for the ring opening polymerization of L-lactide into poly-L-lactic acid (PLLA). With [L-lac]/[Zn complex] = 50, the bis-ligated zinc complexes yielded percentage conversion of 14-98% with polymerization times varying from 15-1440 min, where the longest reaction times were required when two trifluoromethyl groups were present. The addition of 4-fluorophenol co-catalyst resulted in up to a 5-fold increase in the percentage conversion in toluene solution and up to a 14-fold increase in bulk melt polymerization with reductions in the poly-dispersity index values for the isolated PLLA. Addition of 4-fluorophenol to complex 1 was studied with (1)H and (19)F NMR and appeared to yield an in situ generated zinc alkoxide complex.

Toxic or noxious substances often serve as a means of chemical defense for numerous taxa. However, such compounds may also facilitate ecological or evolutionary processes. The neurotoxin, tetrodotoxin (TTX), which is found in newts of the genus Taricha, acts as a selection pressure upon predatory garter snakes, is a chemical cue to conspecific larvae, which elicits antipredator behavior, and may also affect macroinvertebrate foraging behavior. To understand selection patterns and how potential variation might affect ecological and evolutionary processes, it is necessary to quantify TTX levels within individuals and populations. To do so has often required that animals be destructively sampled or removed from breeding habitats and brought into the laboratory. Here we demonstrate a non-destructive method of sampling adult Taricha that obviates the need to capture and collect individuals. We also show that embryos from oviposited California newt (Taricha torosa) egg masses can be individually sampled and TTX quantified from embryos. We employed three different extraction techniques to isolate TTX. Using a custom fabricated high performance liquid chromatography (HPLC) system we quantified recovery of TTX. We found that a newly developed micro-extraction technique significantly improved recovery compared to previously used methods. Results also indicate our improvements to the HPLC method have high repeatability and increased sensitivity, with a detection limit of 48 pg (0.15 pmol) TTX. The quantified amounts of TTX in adult newts suggest fine geographic variation in toxin levels between sampling localities isolated by as little as 3 km.

This article describes a laboratory investigation in which a binary mixture of organic compounds is analyzed first by FTIR spectroscopy to identify the predominant functional groups possessed by the components in the mixture, followed by the determination of the components of the mixture with gas chromatographic separation using a Vernier Mini GC. The components are identified by comparison to authentic standards. Students gain experience in functional group elucidation, selecting operating conditions for a gas chromatographic separation, and operating a simple gas chromatograph early in their academic career. To our knowledge, this represents the first reported coupling of the methods of FTIR spectroscopy and the Vernier GC in the traditionally first-year chemistry course.