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Sex chromosome replacement is frequent in many vertebrate clades, including fish, frogs, and lizards. In order to understand the mechanisms responsible for sex chromosome turnover and the early stages of sex chromosome divergence, it is necessary to study lineages with recently evolved sex chromosomes. Here we examine sex chromosome evolution in a group of African cichlid fishes (tribe Tropheini) which began to diverge from one another less than 4 MYA. We have evidence for a previously unknown sex chromosome system, and preliminary indications of several additional systems not previously reported in this group. We find a high frequency of sex chromosome turnover and estimate a minimum of 14 turnovers in this tribe. We date the origin of the most common sex determining system in this tribe (XY-LG5/19) near the base of one of two major sub-clades of this tribe, about 3.4 MY ago. Finally, we observe variation in the size of one sex-determining region that suggests independent evolution of evolutionary strata in species with a shared sex-determination system. Our results illuminate the rapid rate of sex chromosome turnover in the tribe Tropheini and set the stage for further studies of the dynamics of sex chromosome evolution in this group.

 

In our continued investigations of microbial globins, we solved the structure of a truncated hemoglobin from Shewanella benthica, an obligate psychropiezophilic bacterium. The distal side of the heme active site is lined mostly with hydrophobic residues, with the exception of a tyrosine, Tyr34 (CD1) and a histidine, His24 (B13). We found that purified SbHbN, when crystallized in the ferric form with polyethylene glycol as precipitant, turned into a green color over weeks. The electron density obtained from the green crystals accommodated a trans heme d, a chlorin-type derivative featuring a γ-spirolactone and a vicinal hydroxyl group on a pyrroline ring. In solution, exposure of the protein to one equivalent of hydrogen peroxide resulted in a similar green color change, but caused by the formation of multiple products. These were oxidation species released on protein denaturation, likely including heme d, and a species with heme covalently attached to the polypeptide. The Tyr34Phe replacement prevented the formation of both heme d and the covalent linkage. The ready modification of heme b by SbHbN expands the range of chemistries supported by the globin fold and offers a route to a novel heme cofactor. 

Background: Adolescents frequently experience and witness violence and crime, yet very little research has been conducted to determine how best to question these witnesses to elicit complete and accurate disclosures. Objective: This systematic review integrated scientific research on rapport building with child and adult witnesses with theory and research on adolescent development in order to identify rapport building techniques likely to be effective with suspected adolescent victims and witnesses. Method: Four databases were searched to identify investigations of rapport building in forensic interviewing of adolescents. Results: Despite decades of research of studies including child and adult participants, only one study since 1990 experimentally tested techniques to build rapport with adolescents. Most rapport strategies used with children and adults have yet to be tested with adolescents. Tests of these strategies, along with modifications based on developmental science of adolescence, would provide a roadmap to determining which approaches are most beneficial when questioning adolescent victims and witnesses. Conclusions: There is a clear need for research that tests what strategies are best to use with adolescents. They may be reluctant to disclose information about stressful or traumatic experi- ences to adults due to both normative developmental processes and the types of events about which they are questioned in legal settings. Rapport building approaches tailored to address adolescents’ motivational needs may be effective in increasing adolescents’ reporting, and additional research testing such approaches will provide much-needed insight to inform the development of evidence-based practices for questioning these youth 

Background: Adolescents frequently experience and witness violence and crime, yet very little research has been conducted to determine how best to question these witnesses to elicit complete and accurate disclosures. Objective: This systematic review integrated scientific research on rapport building with child and adult witnesses with theory and research on adolescent development in order to identify rapport building techniques likely to be effective with suspected adolescent victims and witnesses. Method: Four databases were searched to identify investigations of rapport building in forensic interviewing of adolescents. Results: Despite decades of research of studies including child and adult participants, only one study since 1990 experimentally tested techniques to build rapport with adolescents. Most rapport strategies used with children and adults have yet to be tested with adolescents. Tests of these strategies, along with modifications based on developmental science of adolescence, would provide a roadmap to determining which approaches are most beneficial when questioning adolescent victims and witnesses. Conclusions: There is a clear need for research that tests what strategies are best to use with adolescents. They may be reluctant to disclose information about stressful or traumatic experiences to adults due to both normative developmental processes and the types of events about which they are questioned in legal settings. Rapport building approaches tailored to address adolescents’ motivational needs may be effective in increasing adolescents’ reporting, and additional research testing such approaches will provide much-needed insight to inform the development of evidence-based practices for questioning these youth. 

Whenever developers choose among alternative technical approaches, they make a design decision. Collectively, design decisions shape how software implements its requirements and shape non-functional quality attributes such as maintainability, extensibility, and performance. Developers work with design decisions both when identifying, choosing, and documenting alternatives and when later work requires following and understanding previously made design decisions. Design decisions encompass design rationale, describing the alternatives and justification for a design choice, as well as design rules, describing the constraints imposed by specific alternatives. This article summarizes and classifies research on these activities, examining different approaches through which tools may support developers in working with design decisions in code. We focus both on the technical aspects of tools as well as the human aspects of how tools support developers. Our survey identifies goals developers have in working with design decisions throughout the lifecycle of design decisions. We also examine the potential support tools may offer developers in achieving these goals and the challenges in offering better support. 

The year 2024 marks 70 years since the general outline of the carbon pathway in photosynthesis was published. Although several alternative pathways are now known, it is remarkable how many organisms use the reaction sequence described 70 yrs ago, which is now known as the Calvin–Benson cycle or variants such as the Calvin–Benson–Bassham cycle or Benson–Calvin cycle. However, once the carbon has entered the Calvin–Benson cycle and is converted to a 3-carbon sugar, it has many potential fates. This review will examine the last stages of photosynthetic metabolism in leaves. In land plants, this process mostly involves the production of sucrose provided by an endosymbiont (the chloroplast) to its host for use and transport to the rest of the plant. Photosynthetic metabolism also usually involves the synthesis of starch, which helps maintain respiration in the dark and enables the symbiont to supply sugars during both the day and night. Other end products made in the chloroplast are closely tied to photosynthetic CO2 assimilation. These include serine from photorespiration and various amino acids, fatty acids, isoprenoids, and shikimate pathway products. I also describe 2 pathways that can short circuit parts of the Calvin–Benson cycle. These final processes of photosynthetic metabolism play many important roles in plants.

 

Oogenesis is a complex process regulated by precise coordination of multiple factors, including maternal genes. Zygote arrest 1 (zar1) has been identified as an ovary-specific maternal gene that is vital for oocyte-to-embryo transition and oogenesis in mouse and zebrafish. However, its function in other species remains to be elucidated. In the present study, zar1 was identified with conserved C-terminal zinc finger domains in Nile tilapia. zar1 was highly expressed in the ovary and specifically expressed in phase I and II oocytes. Disruption of zar1 led to the failed transition from oogonia to phase I oocytes, with somatic cell apoptosis. Down-regulation and failed polyadenylation of figla, gdf9, bmp15 and wee2 mRNAs were observed in the ovaries of zar1􀀀 /􀀀 fish. Cpeb1, a gene essential for polyadenylation that interacts with Zar1, was down-regulated in zar1􀀀 /􀀀 fish. Moreover, decreased levels of serum estrogen and increased levels of androgen were observed in zar1􀀀 /􀀀 fish. Taken together, zar1 seems to be essential for tilapia oogenesis by regulating polyadenylation and estrogen synthesis. Our study shows that Zar1 has different molecular functions during gonadal development by the similar signaling pathway in different species. 

Mutualistic symbioses between cnidarians and photosynthetic algae are modulated by complex interactions between host immunity and environmental conditions. Here, we investigate how symbiosis interacts with food limitation to influence gene expression and stress response programming in the sea anemoneExaiptasia pallida(Aiptasia). Transcriptomic responses to starvation were similar between symbiotic and aposymbiotic Aiptasia; however, aposymbiotic anemone responses were stronger. Starved Aiptasia of both symbiotic states exhibited increased protein levels of immune-related transcription factor NF-κB, its associated gene pathways, and putative target genes. However, this starvation-induced increase in NF-κB correlated with increased immunity only in symbiotic anemones. Furthermore, starvation had opposite effects on Aiptasia susceptibility to pathogen and oxidative stress challenges, suggesting distinct energetic priorities under food scarce conditions. Finally, when we compared starvation responses in Aiptasia to those of a facultative coral and non-symbiotic anemone, ‘defence’ responses were similarly regulated in Aiptasia and the facultative coral, but not in the non-symbiotic anemone. This pattern suggests that capacity for symbiosis influences immune responses in cnidarians. In summary, expression of certain immune pathways—including NF-κB—does not necessarily predict susceptibility to pathogens, highlighting the complexities of cnidarian immunity and the influence of symbiosis under varying energetic demands.

 

In recent years, anthropogenic activities and climate change have significantly increased exposure of plants to environmental stresses (single or multiple) and pollutants, with negative consequences for the survival and productivity of vegetation. Plants may activate an armament of defenses against stresses. Isoprene, the most abundant biogenic volatile organic compound (BVOC) emitted by plants, is supposed to have a direct or indirect antioxidant role by quenching reactive oxygen species (ROS) or by reprogramming gene expression for antioxidant activation. On the other hand, isoprene is involved in the chemistry of troposphere, further contributing to a build up of pollutants when mixing with anthropogenic gases. In this review, we summarize present knowledge on the impact of air and soil pollutants on isoprene emission by plants, indicating possible feedback and feedforward mechanisms that may affect whole ecosystem functioning and evolution of plant species.