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1. ³¹ P NMR Evidence for Peroxide Intermediates in Lipid Emulsion Photooxidations: Phosphine Substituent Effects in Trapping

   https://doi.org/10.1111/php.12810  

   Mohapatra, Prabhu P. ; Chiemezie, Callistus O. ; Kligman, Arina ; Kim, Michele M. ; Busch, Theresa M. ; Zhu, Timothy C. ; Greer, Alexander ( September 2017 , Photochemistry and Photobiology)

   Intralipid is a lipid emulsion used in photodynamic therapy (PDT) for its light scattering and tissue‐simulating properties. The purpose of this study is to determine whether or not Intralipid undergoes photooxidation, and we have carried out an Intralipid peroxide trapping study using a series of phosphines [2′‐dicyclohexylphosphino‐2,6‐dimethoxy‐1,1′‐biphenyl‐3‐sulfonate, 3‐(diphenylphosphino)benzenesulfonate, triphenylphosphine‐3,3′,3′′‐trisulfonate and triphenylphosphine]. Our new findings are as follows: (1) An oxygen atom is transferred from Intralipid peroxide to the phosphine traps in the dark, after the photooxidation of Intralipid. 3‐(Diphenylphosphino)benzenesulfonate is the most suitable trap in the series owing to a balance of nucleophilicity and water solubility. (2) Phosphine trapping and monitoring by³¹PNMRare effective in quantifying the peroxides in H₂O. An advantage of the technique is that peroxides are detected in H₂O; deuteratedNMRsolvents are not required. (3) The percent yield of the peroxides increased linearly with the increase in fluence from 45 to 180 J cm⁻²based on our trapping experiments. (4) The photooxidation yields quantitated by the phosphines and³¹PNMRare supported by the direct¹HNMRdetection using deuteratedNMRsolvents. These data provide the first steps in the development of Intralipid peroxide quantitation afterPDTusing phosphine trapping and³¹PNMRspectroscopy.
2. Effects of chemical preservation on bulk and amino acid isotope ratios of zooplankton, fish, and squid tissues

   https://doi.org/10.1002/rcm.8408  

   Hetherington, Elizabeth D. ; Kurle, Carolyn M. ; Ohman, Mark D. ; Popp, Brian N. ( April 2019 , Rapid Communications in Mass Spectrometry)

   It is imperative to understand how chemical preservation alters tissue isotopic compositions before using historical samples in ecological studies. Specifically, although compound‐specific isotope analysis of amino acids (CSIA‐AA) is becoming a widely used tool, there is little information on how preservation techniques affect amino acidδ¹⁵N values.

   We evaluated the effects of chemical preservatives on bulk tissueδ¹³C andδ¹⁵N and amino acidδ¹⁵N values, measured by gas chromatography/isotope ratio mass spectrometry (GC/IRMS), of (a) tuna (Thunnus albacares) and squid (Dosidicus gigas) muscle tissues that were fixed in formaldehyde and stored in ethanol for 2 years and (b) two copepod species,Calanus pacificusandEucalanus californicus, which were preserved in formaldehyde for 24–25 years.

   Tissues in formaldehyde‐ethanol had higher bulkδ¹⁵N values (+1.4,D. gigas; +1.6‰,T. albacares), higherδ¹³C values forD. gigas(+0.5‰), and lowerδ¹³C values forT. albacares(−0.8‰) than frozen samples. The bulkδ¹⁵N values from copepods were not different those from frozen samples, although theδ¹³C values from both species were lower (−1.0‰ forE. californicusand −2.2‰ forC. pacificus) than those from frozen samples. The mean amino acidδ¹⁵N values from chemically preserved tissues were largely within 1‰ of those of frozen tissues, but the phenylalanineδ¹⁵N values were altered to a larger extent (range: 0.5–4.5‰).

   The effectsmore »of preservation on bulkδ¹³C values were variable, where the direction and magnitude of change varied among taxa. The changes in bulkδ¹⁵N values associated with chemical preservation were mostly minimal, suggesting that storage in formaldehyde or ethanol will not affect the interpretation ofδ¹⁵N values used in ecological studies. The preservation effects on amino acidδ¹⁵N values were also mostly minimal, mirroring bulkδ¹⁵N trends, which is promising for future CSIA‐AA studies of archived specimens. However, there were substantial differences in phenylalanine and valineδ¹⁵N values, which we speculate resulted from interference in the chromatographic resolution of unknown compounds rather than alteration of tissue isotopic composition due to chemical preservation.

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3. Effects of Formica podzolica ant colonies on soil moisture, nitrogen, and plant communities near nests

   https://doi.org/10.1111/een.12677  

   Sankovitz, Madison A. ; Breed, Michael D. ; McCreery, Helen F. ( October 2018 , Ecological Entomology)

   1. Ants are widely regarded as ‘ecosystem engineers’ because their nest construction and contributions to nutrient cycling change the biological, chemical, and physical properties of the soil around their nests. Despite increasing attention to ant manipulation of soil ecosystems, the extent to which many common species influence soil properties, as well as nutrient uptake and community composition of plants near nests, is still unknown.

   2. This study tested hypotheses that activities of a common subalpine ant,Formica podzolica, alter soil moisture and pH, redistribute nitrogen around nests, and affect plant species abundance and ground cover.

   3. A combination of field sampling techniques showed that distance from a nest had a positive relationship with soil moisture and a negative relationship with plant abundance next to and downhill from nests. Slope aspect also affected plant communities, with downhill transects having higher plant cover and above‐ground biomass than uphill transects. A stable isotope analysis did not reveal that plants near nests had enriched¹⁵N, but there were substantial differences in¹⁵N among sites.

   4. Overall, this study uncovers significant impacts ofF. podzolicaon the subalpine microhabitats directly surrounding their nests.
4. Three gene phylogeny of the Thoreales (Rhodophyta) reveals high species diversity

   https://doi.org/10.1111/jpy.12618  

   Johnston, Emily T. ; Dixon, Kyatt R. ; West, John A. ; Buhari, Nurliah ; Vis, Morgan L. ; Gabrielson, ed., P. ( February 2018 , Journal of Phycology)

   The freshwater red algal order Thoreales has triphasic life history composed of a diminutive diploid “Chantransia” stage, a distinctive macroscopic gametophyte with multi‐axial growth and carposporophytes that develop on the gametophyte thallus. This order is comprised of two genera,ThoreaandNemalionopsis.Thoreahas been widely reported with numerous species, whereasNemalionopsishas been more rarely observed with only a few species described.DNAsequences from three loci (rbcL,cox1, andLSU) were used to examine the phylogenetic affinity of specimens collected from geographically distant locations including North America, South America, Europe, Pacific Islands, Southeast Asia, China, and India. Sixteen species ofThoreaand two species ofNemalionopsiswere recognized. Morphological observations confirmed the distinctness of the two genera and also provided some characters to distinguish species. However, many of the collections were in “Chantransia” stage rather than gametophyte stage, meaning that key diagnostic morphological characters were unavailable. Three new species are proposed primarily based on theDNAsequence data generated in this study,Thorea kokosinga‐pueschelii,T. mauitukitukii,andT. quisqueyana. In addition to these newly described species, oneDNAsequence from GenBank was not closely associated with otherThoreaclades and may represent further diversity in the genus. Two species inNemalionopsisare recognized,N. shawiiandN. parkerinom. et stat. nov.Thoreaharbors more diversity than had been recognized by morphological data alone. Distribution data indicated thatNemalionopsisis common in the Pacificmore »region, whereasThoreais more globally distributed. Most species ofThoreahave a regional distribution, butThorea hispidaappears to be cosmopolitan.

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5. How does genome size affect the evolution of pollen tube growth rate, a haploid performance trait?

   https://doi.org/10.1002/ajb2.1326  

   Reese, John B. ; Williams, Joseph H. ( July 2019 , American Journal of Botany)

   Male gametophytes of most seed plants deliver sperm to eggs via a pollen tube. Pollen tube growth rates (PTGRs) of angiosperms are exceptionally rapid, a pattern attributed to more effective haploid selection under stronger pollen competition. Paradoxically, whole genome duplication (WGD) has been common in angiosperms but rare in gymnosperms. Pollen tube polyploidy should initially acceleratePTGRbecause increased heterozygosity and gene dosage should increase metabolic rates. However, polyploidy should also independently increase tube cell size, causing more work which should decelerate growth. We asked how genome size changes have affected the evolution of seed plantPTGRs.

   We assembled a phylogenetic tree of 451 species with knownPTGRs. We then used comparative phylogenetic methods to detect effects of neo‐polyploidy (within‐genus origins),DNAcontent, andWGDhistory onPTGR, and correlated evolution ofPTGRandDNAcontent.

   Gymnosperms had significantly higherDNAcontent and slowerPTGRoptima than angiosperms, and theirPTGRandDNAcontent were negatively correlated. For angiosperms, 89% of model weight favored Ornstein‐Uhlenbeck models with a fasterPTGRoptimum for neo‐polyploids, whereasPTGRandDNAcontent were not correlated. For within‐genus and intraspecific‐cytotype pairs,PTGRs of neo‐polyploids < paleo‐polyploids.

   Genome size increases should negatively affectPTGRwhen genetic consequences ofWGDs are minimized, as found in intra‐specific autopolyploids (low heterosis) and gymnosperms (fewWGDs). But in angiosperms, the higherPTGRoptimum of neo‐polyploidsmore »and non‐negativePTGR‐DNAcontent correlation suggest that recurrentWGDs have caused substantialPTGRevolution in a non‐haploid state.

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