Spatial resolution and location impact group structure in a marine food web

Ecological processes in food webs depend on species interactions. By identifying broad‐scaled interaction patterns, important information on species' ecological roles may be revealed. Here, we use the group model to examine how spatial resolution and proximity influence group structure. We examine a data set from the Barents Sea, with food webs described for both the whole region and 25 subregions. We test how the group structure in the networks differ comparing (1) the regional metaweb to subregions and (2) subregion to subregion. We find that more than half the species in the metaweb change groups when compared to subregions. Between subregions, networks with similar group structure are spatially related. Interestingly, although species overlap is important for similarity in group structure, there are notable exceptions. Our results highlight that species ecological roles vary depending on fine‐scaled differences in the patterns of interactions, and that local network characteristics are important to consider.     

Enantiopure ethyl 2,3-dibromopropionate: Enantioselective synthesis vs preparative HPLC enantioseparation of racemate on multigram scale

Racemic ethyl 2,3-dibromopropionate, commercially available at low price, is a key intermediate used in the synthesis of several heterocycle fragments, which are present in many biologically active compounds. Surprisingly, the enantiomers are not commercially available and have never been described in the literature. In this work, we undertook two different strategies to obtain these enantiomers, which are enantioselective synthesis and preparative HPLC enantioseparation of commercially available racemate on multigram scale. The first strategy has proved inadequate because racemization occurred during the synthesis (ee ≈ 9-50%). Conversely, the second strategy produced a very good enantioseparation of commercially available racemate (ee > 99.5% for both enantiomers) on multigram scale.     

Axial chirality in biaryl N,N-dialkylaminopyridine derivatives bearing an internal carboxy group

Axial chirality in N,N-dimethylaminopyridines as well as N,N-dipropylaminopyridines bearing an internal carboxy group were evaluated based on their racemization barriers and circular dichroism spectra. The half-life of racemization of N,N-dipropylaminopyridine derivative 2 was estimated to be 19.7 days at 20°C. Its enantiomers isolated as optically active forms showed positive-negative and negative-positive Cotton effects for (+)- 2 and (−)- 2 , respectively, from 310 to 210 nm. Furthermore, (−)- 2 was applied as a chiral nucleophilic catalyst and exhibited asymmetric induction in acylative kinetic resolution of 1-(1-naphthyl)ethane-1-ol.     

A novel method for preparing Eligulstat through chiral resolution

Eliglustat is a ceramide glucosyltransferase inhibitor work as first line oral therapy for adults with Gaucher disease type 1 (a rare disease) at present. Although the eliglustat in enantiomerically pure forms is obtained by asymmetric syntheses, the reported methods suffer from many limits when it comes to industrial applications. Therefore, the preparation of a racemic mixture followed by resolution can still be a viable and straightforward alternative, especially when it could be adapted to large scale. Herein, we developed an effective and practical synthetic route to prepare stereoisomers mixture of eliglustat, and a novel chiral resolution method to prepare eliglustat. Using 1,1′-Binaphthyl-2,2′-diyl -hydrogenphosphate (BNDHP) as resolution reagent, optical pure eliglustat (e.e. >99%, 13.97% total yield) could be obtained after recrystallization.     

Occupancy versus colonization–extinction models for projecting population trends at different spatial scales

Understanding spatiotemporal population trends and their drivers is a key aim in population ecology. We further need to be able to predict how the dynamics and sizes of populations are affected in the long term by changing landscapes and climate. However, predictions of future population trends are sensitive to a range of modeling assumptions. Deadwood‐dependent fungi are an excellent system for testing the performance of different predictive models of sessile species as these species have different rarity and spatial population dynamics, the populations are structured at different spatial scales, and they utilize distinct substrates. We tested how the projected large‐scale occupancies of species with differing landscape‐scale occupancies are affected over the coming century by different modeling assumptions. We compared projections based on occupancy models against colonization–extinction models, conducting the modeling at alternative spatial scales and using fine‐ or coarse‐resolution deadwood data. We also tested effects of key explanatory variables on species occurrence and colonization–extinction dynamics. The hierarchical Bayesian models applied were fitted to an extensive repeated survey of deadwood and fungi at 174 patches. We projected higher occurrence probabilities and more positive trends using the occupancy models compared to the colonization–extinction models, with greater difference for the species with lower occupancy, colonization rate, and colonization:extinction ratio than for the species with higher estimates of these statistics. The magnitude of future increase in occupancy depended strongly on the spatial modeling scale and resource resolution. We encourage using colonization–extinction models over occupancy models, modeling the process at the finest resource‐unit resolution that is utilizable by the species, and conducting projections for the same spatial scale and resource resolution at which the model fitting is conducted. Further, the models applied should include key variables driving the metapopulation dynamics, such as the availability of suitable resource units, habitat quality, and spatial connectivity.     

酰基供体结构对褶皱念珠茵脂肪酶（CRL）催化芳香仲醇动力学拆分立体选择性的影响

研究仲醇的酶催化动力学拆分机制,发现酰基供体的结构是影响酶催化动力学拆分选择性的一个重要因素。通过实验发现了一类用于仲醇动力学拆分（KR）的优秀酰基供体——长链有机酸的对氯苯酚酯,并将这种酰基供体成功用于褶皱念珠菌脂肪酶（CRL）催化的仲醇动力学拆分过程。在1-苯乙醇的动力学拆分（KR）过程中,随着对氯苯酚有机酸酯供体中酰基部分碳原子数的增加,产物的对映体过量值（e．e.p值）也在不断地提高。当碳原子数≥5,转化率达到50％时,产物的叫．。值仍能保持大于99％。这样的规律也适用于其他的仲醇拆分过程,当选择对氯苯酚戊酸酯作为酰基供体用于其他仲醇的动力学拆分过程时,可以实现仲醇的高效拆分,反应6h转化率达到50％,产物的对映体过量值e．e．p为100％。     

Building cross‐cultural coalitions: A case‐study of the Black‐Korean Alliance and the Latino‐Black Roundtable

A case‐study is presented of two Los Angeles‐based cross‐cultural coalitions, the Black‐Korean Alliance [BKA] and the Latino‐Black Roundtable [LBR]. An analysis of the development and eventual dissolution of these two coalitions is presented against the backdrop of the history of relations between the African‐American, Korean‐American and Latino communities of Los Angeles. The central issues leading to the breakup of the two coalitions were: lack of resources, internal power dynamics between coalition partners, nationalistic factions within the broader communities, cross‐cultural dynamics between coalition members, the use of a dialogue model to frame coalition activities, and the analysis of intergroup relations underlying the formation of the coalitions. The applied and theoretical implications of the research are discussed.     

Teaching ethnic and racial relations: some comments on Michael Banton

Banton's critique of race and ethnic relations highlights differences between the U.K. and the U.S.A. The interplay between ethnic politics and the teaching of the subject in the universities reflects differing reactions to the demise of Marxism, the impact of globalization and the growth of transnationalism. In America, anthropology, economics, cultural studies and conflict resolution have had a mixed impact on the field, but an examination of textbooks over the past thirty years - as well as Banton's prolific scholarship - suggests that most of the core problems remain the same.     

Ly6C+Ly6G− Myeloid‐derived suppressor cells play a critical role in the resolution of acute inflammation and the subsequent tissue repair process after spinal cord injury

Acute inflammation is a prominent feature of central nervous system (CNS) insult and is detrimental to the CNS tissue. Although this reaction spontaneously diminishes within a short period of time, the mechanism underlying this inflammatory resolution remains largely unknown. In this study, we demonstrated that an initial infiltration of Ly6C⁺Ly6G^? immature monocyte fraction exhibited the same characteristics as myeloid‐derived suppressor cells (MDSCs), and played a critical role in the resolution of acute inflammation and in the subsequent tissue repair by using mice spinal cord injury (SCI) model. Complete depletion of Ly6C⁺Ly6G^? fraction prior to injury by anti‐Gr‐1 antibody (clone: RB6‐8C5) treatment significantly exacerbated tissue edema, vessel permeability, and hemorrhage, causing impaired neurological outcomes. Functional recovery was barely impaired when infiltration was allowed for the initial 24 h after injury, suggesting that MDSC infiltration at an early phase is critical to improve the neurological outcome. Moreover, intraspinal transplantation of ex vivo‐generated MDSCs at sites of SCI significantly reduced inflammation and promoted tissue regeneration, resulting in better functional recovery. Our findings reveal the crucial role of an Ly6C⁺Ly6G^? fraction as MDSCs in regulating inflammation and tissue repair after SCI, and also suggests an MDSC‐based strategy that can be applied to acute inflammatory diseases.