Climatic niche shift of an invasive shrub (Ulex europaeus): a global scale comparison in native and introduced regions

Aims Invasive species,which recently expanded,may help understand how climatic niche can shift at the time scale of the current global change.Here,we address the climatic niche shift of an invasive shrub(common gorse,Ulex europaeus)at the world and regional scales to assess how it could contribute to increasing invasibility.Methods Based on a 28187 occurrences database,we used a combination of 9 species distribution models(SDM)to assess regional climatic niche from both the native range(Western Europe)and the introduced range in different parts of the world(North-West America,South America,North Europe,Australia and New Zealand).Important Findings Despite being restricted to annual mean temperature between 4℃ and 22℃,as well as annual precipitation higher than 300 mm/year,the range of bioclimatic conditions suitable for gorse was very large.Based on a native versus introduced SDM comparison,we highlighted a niche expansion in North-West America,South America and to a lesser degree in Australia,while a niche displacement was assessed in North Europe.These niche changes induced an increase in potential occupied areas by gorse by 49,111,202 and 283%in Australia,North Europe,North-West America and South America,respectively.On the contrary,we found no evidence of niche change in New Zealand,which presents similar climatic condition to the native environment(Western Europe).This study highlights how niche expansion and displacement of gorse might increase invasibility at regional scale.The change in gorse niche toward new climatic conditions may result from adaptive plasticity or genetic evolution and may explain why it has such a high level of invasibility.Taking into account the possibility of a niche shift is crucial to improve invasive plants management and control.

IgD class switch recombination is not controlled through the immunoglobulin heavy chain 3′ regulatory region super-enhancer

In secondary lymphoid organs,mature B cells express membrane immunoglobulin(Ig)of M and D isotypes(IgM and IgD,respectively)of the same specificity through alternative splicing of a pre-mRNA encompassing the VDJ variable region and Cμand Cδheavy chain constant exons.1 After encountering antigen,B cells undergo class switch recombination(CSR)by which the Cμgene is substituted with Cγ,Cεor Cα,thereby generating IgG,IgE and IgA antibodies of the same antigenic specificity but with new effector functions.CSR requires the DNA-editing enzyme activation-induced deaminase(AID).

The IgH 3′ regulatory region super-enhancer does not control IgA class switch recombination in the B1 lineage

The bone marrow-derived B2 population represents the vast majority of bone marrow,blood,lymph node and splenic B-cells.Mouse B1 B-cells mostly originate during embryonic life in the liver and represent the main B-cell population in the pleural and peritoneal cavities.1,2,3,4,5 B1 and B2 B-cells differ in their origin,antigen specificity,cell surface markers,tissue distribution and capacity for class switch recombination(CSR).Schematically,B1 B-cells appear earlier than B2 B-cells during fetal development and maintain their self-renewal ability throughout their life.

Comparison of alternative arterial anastomosis site during liver transplantation when the recipient’s hepatic artery is unusable

Background:Few studies have analyzed outcomes of liver transplantation(LT)when the recipient hepatic artery(HA)was not usable.Methods:We retrospectively evaluated the outcomes of LT performed using the different alternative sites to HA.Results:Between 2002 and 2017,1,677 LT were performed in our institution among which 141(8.4%)with unusable recipient HA were analyzed.Four groups were defined according to the site of anastomosis:the splenic artery(SA group,n=26),coeliac trunk(CT group,n=12),aorta using or not the donor’s vessel(Ao group,n=91)and aorta using a vascular prosthesis(Ao-P group,n=12)as conduit.The median number of intraoperative red blood cell transfusions was significantly increased in the Ao and Ao-P groups(5,5,8.5 and 16 for SA,CT,Ao and Ao-P group respectively,P=0.002),as well as fresh frozen plasma(4.5,2.5,10,17 for the SA,CT,Ao and Ao-P groups respectively,P=0.001).Hospitalization duration was also significantly increased in the Ao and Ao-P groups(15,16,24,26.5 days for the SA,CT,Ao and Ao-P groups respectively,P<0.001).The occurrence of early allograft dysfunction(EAD)(P=0.07)or arterial complications(P=0.26)was not statistically different.Level of factor V,INR,bilirubin and creatinine during the 7th postoperative days(POD)was significantly improved in the SA group.No difference was observed regarding graft(P=0.18)and patient(P=0.16)survival.Conclusions:In case of unusable HA,intraoperative and postoperative outcomes are improved when using the SA or CT compared to aorta.

Pure Hydrocarbons:An Efficient Molecular Design Strategy for the Next Generation of Host Materials for Phosphorescent Organic Light-Emitting Diodes

CONSPECTUS:Fantastic progresses have been made since the discovery of phosphorescent organic light-emitting diodes(PhOLEDs)in 1998(Nature 1998,395,151).In the emissive layer of a PhOLED,a heavy-metal complex(emitter)is dispersed as a guest in an organic semiconductor(host)in order to harvest both singlet and triplet excitons.This host/guest technique is essential to reach highperformance PhOLEDs.Undoubtedly,designing high-efficiency host materials for red,green,and blue phosphors has been the main driving force of the field.Nowadays,the most efficient PhOLEDs report very high external quantum efficiency(EQE)above 27%for the three colors.The molecular design of these high-efficiency host materials is based on small functional units,which have a crucial role in the device performance.These functional units are constructed on the assembly of electron-rich and/or electron-poor molecular fragments(such as carbazole,phenylamine,phosphine oxide,oxadiazole,pyridine,sulfone,etc.),which allows to finely tune the molecular orbitals energy levels(HOMO and LUMO)and the mobility of the charge carriers(hole and electrons).However,these molecular fragments incorporate heteroatoms,which in turn increase the molecular design complexity and production cost of the target materials and also create potential instability in the device.Indeed,the fragile C−N,C−P,and C−S bonds of such heteroatom-based hosts are involved,in part,in the OLED instability.As the instability of OLEDs is one of the most important problem to address at the current stage of development,developing new generations of host materials,without heteroatoms,has appeared as an important challenge in the field.In recent years,this new generation of host materials,called Pure HydroCarbons(PHC),only incorporating carbon and hydrogen atoms,has drawn the attention of the scientific community.PHC host materials only contain benzene rings,one of the most robust and inert building unit,which are assemble with suitable linkages to adjust their energy levels.However,reaching high-performance PhOLEDs with PHC-based hosts has been a real challenge.In the present account,thanks to a structure−properties relationship study,we recount the history of PHC-based host materials for PhOLEDs from the first example published in 2005(Org.Lett.2005,7,5131),to the recent advances,which have shown that PHC hosts can overpass the performance of heteroatom-based hosts(Chem.Sci.2020,11,4887).Our group has contributed over the years to unravel the design principles of PHC hosts in order to improve the devices performance.In the light of recent results,PHC hosts now enter a new era and this work shows that the PHC design strategy is promising for the future development of OLED industry as a high-performance and low-cost option.

Evaluation of soil erosion risk and identification of soil cover and management factor (C) for RUSLE in European vineyards with different soil management

Vineyards show some of the largest erosion rates reported in agricultural areas in Europe.Reported rates vary considerably under the same land use,since erosion processes are highly affected by climate,soil,topography and by the adopted soil management practices.Literature also shows differences in the effect of same conservation practices on reducing soil erosion from conventional,bare soil based,management.The Revised Universal Soil Loss Equation(RUSLE)is commonly adopted to estimate rates of water erosion on cropland under different forms of land use and management,but it requires proper value of soil cover and management(C)factors in order to obtain a reliable evaluation of local soil erosion rates.In this study the ORUSCAL(Orchard RUSle CALibration)is used to identify the best calibration strategy against long-term experimental data.Afterwards,ORUSCAL is used in order to apply the RUSLE technology from farm based information across different European wine-growing regions.The results suggest that the best strategy for calibration should incorporate the soil moisture sub-factor(Sm)to provide better soil loss predictions.The C factor,whose average values ranged from 0.012 to 0.597.presented a large spatial variability due to coupling with local climate and specific local management.The comparison across the five wine-growing regions indicates that for the soil protection management,permanent cover crop is the best measure for accomplishing sustainable erosion rates across the studied areas.Alternate and temporary cover crops,that are used in areas of limited water resources to prevent competition with vines,failed to achieve sustainable erosion rates,that still need to be addressed.This raises the need for a careful use of C values developed under different environmental conditions.

Retraction Note:Trans-silencing effect of the 3′RR immunoglobulin heavy chain enhancer on Igκtranscription at the pro-B cell stage

The authors have retracted this Correspondence.After the publication of this correspondence,it came to the authors’attention that the control RAG2^(−/−)mouse was a RAG2^(−/−)γc^(−/−)mouse.This point resulted in the conclusions being considered invalid.The authors apologize to the journal and its readers for any inconvenience caused.

Retraction Note:3′RR and 5′Eμimmunoglobulin heavy chain enhancers are independent engines of locus remodeling

The authors have retracted this Correspondence.After the publication of this correspondence,it came to the authors’attention that the control RAG2^(−/−)mouse was a RAG2^(−/−)γc^(−/−)mouse.This point resulted in the conclusions being considered invalid.The authors apologize to the journal and its readers for any inconvenience caused.

Trans-silencing effect of the 3′RR immunoglobulin heavy chain enhancer on Igκtranscription at the pro-B cell stage

Due to their impact on nuclear organization,enhancers are master regulators of cell fate.1,2 The immunoglobulin heavy chain(IgH)locus undergoes numerous changes(such as transcription,accessibility,DNA breaks,and mutations)throughout B-cell differentiation.Several of these events are controlled by the IgH 3′regulatory region(3′RR).The 3′RR is the master control element of mature B-cell IgH transcription,3 somatic hypermutation(SHM),4,5 conventional class switch recombination(CSR),4,6–10 and locus suicide recombination(LSR).11 In contrast,the 3′RR is expected to be dispensable for V(D)J recombination.12,13 During Bcell development,the heavy and light chain loci are poised for their VDJ and VJ rearrangements,respectively.The IgH locus rearranges first,with D-J joining at the pro-B-cell stages,followed by V-DJ joining at the pre-B-cell stage.The Igk locus is poised for VJ rearrangements at the pre-B cell stage.

Deletion of the immunoglobulin heavy chain 3′ regulatory region super-enhancer affects somatic hypermutation in B1 B cells

Mouse B1 B cells originate in the embryonic liver and are the major B-cell population in the peritoneal and pleural cavities.1–5 By contrast,mouse B2 B cells originate in the bone marrow and are the major B-cell population in the bone marrow,spleen,and blood.B1 and B2 B cells differ not only in their origin and locations,but also in their antigen specificity,cell surface markers,capacities for class-switch recombination(CSR)and somatic hypermutation(SHM).IgH cis-regulatory regions and,particularly,transcriptional super-enhancers are major locus regulators under both normal and pathological conditions.6,7 Important differences have been found regarding the ability of the IgH 3′regulatory region(3′RR)super-enhancer to control the B1 and B2 B-cell fate.