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1. Reshuffling of the Coral Microbiome during Dormancy

   https://doi.org/10.1128/aem.01391-22  

   Brown, Anya L.; Sharp, Koty; Apprill, Amy (December 2022, Applied and Environmental Microbiology)

   Glass, Jennifer B. (Ed.)

   Using a high-resolution sampling time series, this study is the first to demonstrate a persistent microbial community shift with quiescence (dormancy) in a marine organism, the temperate coralAstrangia poculata. Furthermore, during this period of community turnover, there is a shedding of putative pathogens and copiotrophs and an enhancement of the ammonia-oxidizing bacteria (Nitrosococcales) and archaea (“CandidatusNitrosopumilus”). 

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2. The Legacy of Recurrent Introgression during the Radiation of Hares

   https://doi.org/10.1093/sysbio/syaa088  

   Ferreira, Mafalda S; Jones, Matthew R; Callahan, Colin M; Farelo, Liliana; Tolesa, Zelalem; Suchentrunk, Franz; Boursot, Pierre; Mills, L Scott; Alves, Paulo C; Good, Jeffrey M; et al (December 2020, Systematic Biology)

   Buckley, Thomas (Ed.)

   Abstract Hybridization may often be an important source of adaptive variation, but the extent and long-term impacts of introgression have seldom been evaluated in the phylogenetic context of a radiation. Hares (Lepus) represent a widespread mammalian radiation of 32 extant species characterized by striking ecological adaptations and recurrent admixture. To understand the relevance of introgressive hybridization during the diversification of Lepus, we analyzed whole exome sequences (61.7 Mb) from 15 species of hares (1–4 individuals per species), spanning the global distribution of the genus, and two outgroups. We used a coalescent framework to infer species relationships and divergence times, despite extensive genealogical discordance. We found high levels of allele sharing among species and show that this reflects extensive incomplete lineage sorting and temporally layered hybridization. Our results revealed recurrent introgression at all stages along the Lepus radiation, including recent gene flow between extant species since the last glacial maximum but also pervasive ancient introgression occurring since near the origin of the hare lineages. We show that ancient hybridization between northern hemisphere species has resulted in shared variation of potential adaptive relevance to highly seasonal environments, including genes involved in circadian rhythm regulation, pigmentation, and thermoregulation. Our results illustrate how the genetic legacy of ancestral hybridization may persist across a radiation, leaving a long-lasting signature of shared genetic variation that may contribute to adaptation. [Adaptation; ancient introgression; hybridization; Lepus; phylogenomics.] 

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3. The Stabilizing Function of the Tail During Arboreal Quadrupedalism

   https://doi.org/10.1093/icb/icab096  

   Young, Jesse W; Chadwell, Brad A; Dunham, Noah T; McNamara, Allison; Phelps, Taylor; Hieronymus, Tobin; Shapiro, Liza J (June 2021, Integrative and Comparative Biology)

   Abstract Locomotion on the narrow and compliant supports of the arboreal environment is inherently precarious. Previous studies have identified a host of morphological and behavioral specializations in arboreal animals broadly thought to promote stability when on precarious substrates. Less well-studied is the role of the tail in maintaining balance. However, prior anatomical studies have found that arboreal taxa frequently have longer tails for their body size than their terrestrial counterparts, and prior laboratory studies of tail kinematics and the effects of tail reduction in focal taxa have broadly supported the hypothesis that the tail is functionally important for maintaining balance on narrow and mobile substrates. In this set of studies, we extend this work in two ways. First, we used a laboratory dataset on three-dimensional segmental kinematics and tail inertial properties in squirrel monkeys (Saimiri boliviensis) to investigate how tail angular momentum is modulated during steady-state locomotion on narrow supports. In the second study, we used a quantitative dataset on quadrupedal locomotion in wild platyrrhine monkeys to investigate how free-ranging arboreal animals adjust tail movements in response to substrate variation, focusing on kinematic measures validated in prior laboratory studies of tail mechanics (including the laboratory data presented). Our laboratory results show that S. boliviensis significantly increase average tail angular momentum magnitudes and amplitudes on narrow supports, and primarily regulate that momentum by adjusting the linear and angular velocity of the tail (rather than via changes in tail posture per se). We build on these findings in our second study by showing that wild platyrrhines responded to the precarity of narrow and mobile substrates by extending the tail and exaggerating tail displacements, providing ecological validity to the laboratory studies of tail mechanics presented here and elsewhere. In conclusion, our data support the hypothesis that the long and mobile tails of arboreal animals serve a biological role of enhancing stability when moving quadrupedally over narrow and mobile substrates. Tail angular momentum could be used to cancel out the angular momentum generated by other parts of the body during steady-state locomotion, thereby reducing whole-body angular momentum and promoting stability, and could also be used to mitigate the effects of destabilizing torques about the support should the animals encounter large, unexpected perturbations. Overall, these studies suggest that long and mobile tails should be considered among the fundamental suite of adaptations promoting safe and efficient arboreal locomotion. 

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4. The role of Dmnt1 during spermatogenesis of the insect Oncopeltus fasciatus

   https://doi.org/10.1186/s13072-023-00496-5  

   Cunningham, Christopher B.; Shelby, Emily A.; McKinney, Elizabeth C.; Schmitz, Robert J.; Moore, Allen J.; Moore, Patricia J. (December 2023, Epigenetics & Chromatin)

   Abstract Background The function of DNA methyltransferase genes of insects is a puzzle, because an association between gene expression and methylation is not universal for insects. If the genes normally involved in cytosine methylation are not influencing gene expression, what might be their role? We previously demonstrated that gametogenesis of Oncopeltus fasciatus is interrupted at meiosis following knockdown of DNA methyltransferase 1 ( Dnmt1 ) and this is unrelated to changes in levels of cytosine methylation. Here, using transcriptomics, we tested the hypothesis that Dmnt1 is a part of the meiotic gene pathway. Testes, which almost exclusively contain gametes at varying stages of development, were sampled at 7 days and 14 days following knockdown of Dmnt1 using RNAi. Results Using microscopy, we found actively dividing spermatocysts were reduced at both timepoints. However, as with other studies, we saw Dnmt1 knockdown resulted in condensed nuclei after mitosis–meiosis transition, and then cellular arrest. We found limited support for a functional role for Dnmt1 in our predicted cell cycle and meiotic pathways. An examination of a priori Gene Ontology terms showed no enrichment for meiosis. We then used the full data set to reveal further candidate pathways influenced by Dnmt1 for further hypotheses. Very few genes were differentially expressed at 7 days, but nearly half of all transcribed genes were differentially expressed at 14 days. We found no strong candidate pathways for how Dnmt1 knockdown was achieving its effect through Gene Ontology term overrepresentation analysis. Conclusions We, therefore, suggest that Dmnt1 plays a role in chromosome dynamics based on our observations of condensed nuclei and cellular arrest with no specific molecular pathways disrupted. 

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5. Elucidation of the growth mechanism of MoS2 during the CVD process

   https://doi.org/10.1557/adv.2018.660  

   Withanage, Sajeevi S; Lopez, Mike; Sameen, Wasee; Charles, Vanessa; Khondaker, Saiful I (January 2019, MRS Advances)

   ABSTRACT Chemical vapor deposition (CVD) growth of two-dimensional molybdenum disulfide (MoS 2 ) using molybdenum trioxide (MoO 3 ) and sulfur (S) powder often results in intermediate molybdenum oxy-sulfide (MoOS 2 ) species along with MoS 2 due to a lack of control over the vapor pressure required for the clean growth. Much effort has been devoted in understanding and controlling of these intermediate MoOS 2 specifies. Here, we show that with a second step sulfurization at moderate temperatures, these MoOS 2 crystals can be transformed to monolayer MoS 2 crystals. Scanning electron microscopy, Raman and photoluminescence spectroscopy and atomic force microscopy characterization carried out before and after re-sulfurization confirm the monolayer MoS 2 growth via this route. This study shows that MoOS 2 formed at the intermediate state can be successfully recycled to MoS 2 . 

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