Environment differentially affects the functional and phylogenetic structures of plant communities in a dry evergreen Afromontane tropical forest

Testing how local environmental conditions influence plant community assembly is important to understand the underlying mechanisms that promote and/or maintain biodiversity. Functional traits are used to find the broad spectrum of resource use strategies that plants use to respond to environmental variation. The patterns and drivers of plant community assembly through the lens of traits and phylogeny; however, remain to be studied in a uniquely biodiversity rich but poorly known fragmented dry Afromontane forest of Ethiopia. Here, we combined trait and community phylogenetic data from thirty sampling plots of 20 × 20 m size to determine the functional and phylogenetic structures and their drivers in a fragmented, human-dominated dry evergreen Afromontane forest. We found phylogenetic and functional clustering of plants in which the effect of environment was found to be trait specific. A weak phylogenetic signal for traits was detected suggesting that species resource use strategies may not be inferred using species phylogenetic distance. Additionally, we found functional traits to be weak in predicting species abundance distribution. Overall, while this study shows a non-random community assembly pattern, it also highlights the importance of deterministic processes being trait specific.     

Synergistic effect of TRM2/RNC1 and EXO1 in DNA double-strand break repair in Saccharomyces cerevisiae

In our recently published study, we provided in vitro as well as in vivo data demonstrating the involvement of TRM2/RNC1 in homologous recombination based repair (HRR) of DNA double strand breaks (DSBs), in support of such claims reported earlier. To further validate its role in DNA DSB processing, our present study revealed that the trm2 single mutant displays higher sensitivity to persistent induction of specific DSBs at the MAT locus by HO-endonuclease with higher sterility rate among the survivors compared to wild type (wt) or exo1 single mutants. Intriguingly, both sensitivity and sterility rate increased dramatically in trm2exo1 double mutants lacking both endo-exonucleases with a progressively increased sterility rate in trm2exo1 double mutants with short-induction periods, reaching a very high level of sterility with persistent DSB inductions. Mutation analysis of the mating type (MAT) locus among the sterile survivors with persistent HO-induction in trm2 and exo1 single mutants as well as in trm2exo1 double mutants revealed a similar small insertions and deletions events, characteristic of non-homologous end joining (NHEJ) that might have occurred due to the lack of proper processing function in these mutants. In addition, trm2ku80 and trm2rad52 double mutants also displayed significantly higher sterility with persistent DSB induction compared to ku80 and rad52 single mutants, respectively, exhibiting a mutation spectra that shifted from base substitution (in ku80 and rad52 single mutants) to small insertions and deletions in the double mutants (in trm2ku80 and trm2rad52 mutants). These data indicate a defective processing in absence of TRM2, with a synergistic effect of TRM2, and EXO1 in such processing.     

Diversity of medium and large mammals in the Loka Abaya National Park,southern Ethiopia

We evaluated the richness, diversity, and composition of the medium and large mammal community in the Loka Abaya National Park (LANP), southern Ethiopia, and how these parameters differ among four habitat types: wooded grassland, riverine forest, hilly scrubland and wetland, and between seasons. We recorded a total of 2,573 individual animals of 28 medium and large mammal species in the park. This included three globally threatened species: the endangered African wild dog (Lycaon pictus), the vulnerable Leopard (Panthera pardus), and Hippopotamus (Hippopothamus amphibius). Season had little effect on species richness, diversity, and composition both across and within habitat types. However, species richness across seasons was significantly different among the four habitat types, in the declining order of the following: wooded grassland > riverine forest > hilly scrubland > wetland. The strongest similarity in species composition, both across and within seasons, was found between wooded grassland and riverine forest. In terms of relative abundance, mammal assemblage of the wooded grassland and wetland habitats had more evenly distributed number of species with different relative abundance categories. Overall, Anubis Baboon (Papio anubis), Grivet Monkey (Chlorocebus aethiops), and Greater Kudu (Tragelephus strepsiceros) were the three most abundant species across habitat types. In conclusion, findings of our study reveal that LANP plays an important role in Ethiopia's mammal conservation. Our findings will serve as baseline information for managers of the park to make effective conservation decisions and as a baseline for researchers wishing to conduct related ecological studies.     

Infusion reactions in natural killer cell immunotherapy: a retrospective review

Background aimsThe use of natural killer (NK) cells as a cellular immunotherapy has increased over the past decade, specifically in patients with hematologic malignancies. NK cells have been used at the authors’ institution for over 15 years. Most patients have a reaction to NK cell infusion. The authors retrospectively analyzed the reactions associated with NK cell infusions to characterize the types of reactions and investigate why some patients have higher-grade reactions than others.MethodsA retrospective chart review of NK cell infusions was performed at the authors’ institution under nine clinical protocols from 2008 to 2016. An infusion reaction was defined as any symptom from the time of NK cell infusion up to 4 h after infusion completion. The severity of infusion reactions was graded based on Common Terminology Criteria for Adverse Events, version 4. Two major endpoints of interest were (i) infusion reaction with any symptom and (ii) grade ≥3 infusion reaction. Multivariable logistic regression models were used to investigate the association between variables of interest and outcomes. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained for each variable.ResultsA total of 130 patients were receiving NK cell infusions at the authors’ institution. The most common reported symptom was chills (n = 110, 85%), which were mostly grade 1 and 2, with only half of patients requiring intervention. There were 118 (91%) patients with infusion reactions, and only 36 (28%) were grade 3. There was one life-threatening grade 4 reaction, and no death was reported due to infusion reaction. Among grade ≥3 reactions, cardiovascular reactions (mainly hypertension) were the most common, and less than half of those with hypertension required intervention. NK cell dose was not associated with any of the grade 3 infusion reactions, whereas monocyte dose was associated with headache (grade ≤3, OR, 2.17, 95% CI, 1.19–3.97) and cardiovascular reaction (grade ≥3, OR, 2.13, 95% CI, 1.13–3.99). Cardiovascular reaction (grade ≥3) was also associated with in vitro IL-2 incubation and storage time. Additionally, there was no association between grade ≥3 infusion reactions and overall response rate (OR, 0.75, 95% CI, 0.29–1.95).ConclusionsThe majority of patients who receive NK cell therapy experience grade 1 or 2 infusion reactions. Some patients experience grade 3 reactions, which are mainly cardiovascular, suggesting that close monitoring within the first 4 h is beneficial. The association of monocytes with NK cell infusion reaction relates to toxicities seen in adoptive T-cell therapy and needs further exploration.     

Contrasting effects of space and environment on functional and phylogenetic dissimilarity in a tropical forest

Aims The evolutionary history and functional traits of species can illuminate ecological processes supporting coexistence in diverse forest communities. However, little has been done in decoupling the relative importance of these mechanisms on the turnover of phylogenetic and functional characteristics across life stages and spatial scales. Therefore, this study aims to estimate the contribution of environment and dispersal on the turnover of phylogenetic and functional diversity across life stages and spatial scales, in order to build a coherent picture of the processes responsible for species coexistence.     

Complement factor H allotype 402H is associated with increased C3b opsonization and phagocytosis of Streptococcus pyogenes

The mechanisms driving bacterial chromosome segregation remain poorly characterized. While a number of factors influencing chromosome segregation have been described in recent years, none of them appeared to play an essential role in the process comparable to the eukaryotic centromere/spindle complex. The research community involved in bacterial chromosome was becoming familiar with the fact that bacteria have selected multiple redundant systems to ensure correct chromosome segregation. Over the past few years a new perspective came out that entropic forces generated by the confinement of the chromosome in the crowded nucleoid shell could be sufficient to segregate the chromosome. The segregating factors would only be required to create adequate conditions for entropy to do its job. In the article by Yazdi et al. ( 2012 ) in this issue of Molecular Microbiology, this model was challenged experimentally in live Escherichia coli cells. A Fis–GFP fusion was used to follow nucleoid choreography and analyse it from a polymer physics perspective. Their results suggest strongly that E. coli nucleoids behave as self‐adherent polymers. Such a structuring and the specific segregation patterns observed do not support an entropic like segregation model. Are we back to the pre‐entropic era?     

埃塞俄比亚Senkele Swayne保护区斯韦恩麋羚的种群现状与结构

于2005年10月至2006年4月调查了埃塞俄比亚森可勒斯韦恩麋羚保护区旱季和湿季斯韦恩麋羚(Alcelaphus buselaphus swaynei)的种群现状与结构.根据植被类型、道路和沟谷,将研究区划分为5个区域,并且调查了保护区外的一块休耕农地.利用全部计数法计数了每个区域内的斯韦恩麋羚,在28 km2的区域内共统计到283只(湿季)和351只(旱季)麋羚,湿季和旱季的麋羚数量变化显著,其季节间差异是由旱季的出生高峰造成的.斯韦恩麋羚种群中雌性个体占42.7%、雄性占36.0%、幼羚占21.3%.某些区域的麋羚数量要高于其它区域,且无论湿季或旱季斯韦恩麋羚多集中在狼尾草高草地中.斯韦恩麋羚的种群结构随季节而变化,其大集群经常出现在湿季而旱季集群较小.斯韦恩麋羚的种群动态因保护程度的不同在不同时期呈不规则性变化