The microtubule-associated protein She1 coordinates directional spindle positioning by spatially restricting dynein activity.

Dynein motors move the mitotic spindle to the cell division plane in many cell types, including in budding yeast, in which dynein is assisted by numerous factors including the microtubule-associated protein (MAP) She1. Evidence suggests that She1 plays a role in polarizing dynein-mediated spindle movements toward the daughter cell; however, how She1 performs this function is unknown. We find that She1 assists dynein in maintaining the spindle in close proximity to the bud neck, such that, at anaphase onset, the chromosomes are segregated to mother and daughter cells. She1 does so by attenuating the initiation of dynein-mediated spindle movements within the mother cell, thus ensuring such movements are polarized toward the daughter cell. Our data indicate that this activity relies on She1 binding to the microtubule-bound conformation of the dynein microtubule-binding domain, and to astral microtubules within mother cells. Our findings reveal how an asymmetrically localized MAP directionally tunes dynein activity by attenuating motor activity in a spatially confined manner.

Child posttraumatic stress symptoms in an acute injury sample: Patterns of associations among child report, parent report, and child heart rate parameters.

Parent-child agreement on measures of child posttraumatic stress disorder (PTSD) is moderate at best, and understanding of this discrepancy is limited. To address this, we conducted an item-level investigation of parent-child symptom agreement to examine the potential influence of parental posttraumatic stress symptoms (PTSS) on parents' reports of their child's PTSS. We also examined heart rate (HR) indices as possible independent indicators of child PTSD, examining patterns of association with parent versus child report. Parent-child dyads (N = 132, child age: 6-13 years, 91.7% White) were recruited after the child's hospital admission following an acute, single-incident traumatic event. At 1-month posttrauma, questionnaires assessing children's PTSS (self- and parental reports) and parental PTSS were administered. For a subset of participants (n = 70), children's HR recordings were obtained during a trauma narrative task and analyzed. Parent and child reports of child PTSS were weakly positively correlated, r = .25. Parental PTSS were found to be stronger positive predictors of parental reports of child PTSS than the children's own symptom reports, ß = 0.60 vs. ß = 0.14, and were associated with higher parent-reported child PTSS relative to child reports. Finally, children's self-reported PTSS were associated with HR indices, whereas parent reports were not, ßs = -.33-.30 vs. ßs = -.15-.01. Taken together, children's self-reported PTSS could be a more accurate reflection of their posttrauma physiological distress than parent reports. The potential influence of parental PTSS on their perceptions of their child's symptoms warrants further consideration.

Changing the narrative on fisheries subsidies reform: Enabling transitions to achieve SDG 14.6 and beyond.

The World Trade Organization (WTO) is in the final stages of negotiating an agreement to prohibit harmful fisheries subsidies, thereby achieving UN Sustainable Development Goal (SDG) 14.6. An effective agreement should be viewed as an opportunity for nations to proactively transition towards sustainable and equitable fisheries and pave the path for other SDGs. Supporting fishers does not require harmful subsidies, and we provide evidence-based options for reform that highlight equity needs while reducing environmental harm. Subsidy reforms need clear goals, co-design, transparency, and fair implementation. An agreement on SDG 14.6 could be a turning point for the oceans and for the well-being of those that depend on the oceans for livelihoods and nutrition. Responsible seafood production will require international cooperation not only at WTO, but among governments, fisher organizations, civil society, and the wider public.

Invited review: Microtubule severing enzymes couple atpase activity with tubulin GTPase spring loading.

Microtubules are amazing filaments made of GTPase enzymes that store energy used for their own self-destruction to cause a stochastically driven dynamics called dynamic instability. Dynamic instability can be reproduced in vitro with purified tubulin, but the dynamics do not mimic that observed in cells. This is because stabilizers and destabilizers act to alter microtubule dynamics. One interesting and understudied class of destabilizers consists of the microtubule-severing enzymes from the ATPases Associated with various cellular Activities (AAA+) family of ATP-enzymes. Here we review current knowledge about GTP-driven microtubule dynamics and how that couples to ATP-driven destabilization by severing enzymes. We present a list of challenges regarding the mechanism of severing, which require development of experimental and modeling approaches to shed light as to how severing enzymes can act to regulate microtubule dynamics in cells. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 547-556, 2016.

Katanin Severing and Binding Microtubules Are Inhibited by Tubulin Carboxy Tails.

Microtubule dynamics in cells are regulated by associated proteins that can be either stabilizers or destabilizers. A class of destabilizers that is important in a large number of cellular activities is the microtubule-severing enzymes, yet little is known about how they function. Katanin p60 was the first ATPase associated with microtubule severing. Here, we investigate the activity of katanin severing using a GFP-labeled human version. We quantify the effect of katanin concentration on katanin binding and severing activity. We find that free tubulin can inhibit severing activity by interfering with katanin binding to microtubules. The inhibition is mediated by the sequence of the tubulin and specifically depends on the carboxy-terminal tails. We directly investigate the inhibition effect of tubulin carboxy-terminal tails using peptide sequences of α-, ß-, or detyrosinated α-tubulin tails that have been covalently linked to bovine serum albumin. Our results show that ß-tubulin tails are the most effective at inhibiting severing, and that detyrosinated α-tubulin tails are the least effective. These results are distinct from those for other severing enzymes and suggest a scheme for regulation of katanin activity in cells dependent on free tubulin concentration and the modification state of the tubulin.

Habitat and movement selection processes of American lobster/jakej within a restricted bay in the Bras d'Or Lake/Pitu'paq, Nova Scotia, Canada.

American lobster inhabit the unique, brackish Bras d'Or Lake system, although densities are low compared to areas with similar habitats in the Atlantic Ocean. Nevertheless, lobsters are an important part of local First Nation (Mi'kmaq) food and culture. We used acoustic telemetry and habitat mapping, combined with local Mi'kmaw knowledge, to document the movements and habitat use of adult lobsters within a section of the Lake. Movement patterns of acoustically tagged individual lobsters were analyzed with both resource selection functions and integrated step selection functions using data obtained from a high-resolution VEMCO Positioning System within a restricted bay in the Bras d'Or Lake. The resource selection function suggested stronger selections of substrates that contained a combination of soft and hard sediments. While the integrated step selection functions found substantial individual variability in habitat selections, there was a trend for lobsters to exhibit more resident behaviour on the combined soft/hard substrates despite the fact these sediments provided little in the way of obvious shelters for the animals. Adult lobsters at this site have very little risk of predation, which presumably allows them to freely exhibit exploratory behaviours and reduce their association with substrates that provide shelters.

A stakeholder-engaged approach to evaluating spawning aggregation management as a strategy for conserving bonefish (Albula vulpes) in Cuba.

Animals that congregate in large numbers to reproduce in spatially and temporally distinct locations are particularly susceptible to overexploitation. Many fishes form spawning aggregations that are intentionally targeted given ease of capture. Bonefish (Albula spp.) species aggregate to spawn and are culturally and economically important, but generally lack management such as spawning area protections to ensure that fisheries are sustainable. Here, we use Cuba as a case study to inform the development and refinement of management strategies for bonefish. Recommendations for the management of bonefish pre-spawning aggregations were based on international experiences, which have been adapted to the Cuban context from results of surveys and interviews with Cuban fisheries professionals and fishing guides. The achievability and feasibility of recommendations were further reviewed by additional experts in the field of fisheries, management and Cuban policy. The process revealed extensive data-limitations for bonefish fisheries and underscored the importance of including fishing guides, local ecological knowledge and the context of marine protected areas in Cuba for bonefish management. Recommendations include (1) initiating information exchange between Cuban management agencies and third-party institutions related to bonefish management; (2) utilizing local ecological knowledge to gather information, formulate management strategies and enforce regulations; (3) implementing spatial and temporal management measures for bonefish spawning sites; (4) using what is already in place, by protecting spawning sites in the context of existing marine protected areas; (5) collaborating with all stakeholders to manage bonefish spawning sites; and (6) reducing the commercial harvest of the species. Supplementary Information: The online version contains supplementary material available at 10.1007/s10641-022-01355-0.

Drosophila katanin-60 depolymerizes and severs at microtubule defects.

Microtubule (MT) length and location is tightly controlled in cells. One novel family of MT-associated proteins that regulates MT dynamics is the MT-severing enzymes. In this work, we investigate how katanin (p60), believed to be the first discovered severing enzyme, binds and severs MTs via single molecule total internal reflection fluorescence microscopy. We find that severing activity depends on katanin concentration. We also find that katanin can remove tubulin dimers from the ends of MTs, appearing to depolymerize MTs. Strikingly, katanin localizes and severs at the interface of GMPCPP-tubulin and GDP-tubulin suggesting that it targets to protofilament-shift defects. Finally, we observe that binding duration, mobility, and oligomerization are ATP dependent.

An Agrobacterium VirB10 mutation conferring a type IV secretion system gating defect.

Agrobacterium VirB7, VirB9, and VirB10 form a "core complex" during biogenesis of the VirB/VirD4 type IV secretion system (T4SS). VirB10 spans the cell envelope and, in response to sensing of ATP energy consumption by the VirB/D4 ATPases, undergoes a conformational change required for DNA transfer across the outer membrane (OM). Here, we tested a model in which VirB10 regulates substrate passage by screening for mutations that allow for unregulated release of the VirE2 secretion substrate to the cell surface independently of target cell contact. One mutation, G272R, conferred VirE2 release and also rendered VirB10 conformationally insensitive to cellular ATP depletion. Strikingly, G272R did not affect substrate transfer to target cells (Tra(+)) but did block pilus production (Pil(-)). The G272R mutant strain displayed enhanced sensitivity to vancomycin and SDS but did not nonspecifically release periplasmic proteins or VirE2 truncated of its secretion signal. G272 is highly conserved among VirB10 homologs, including pKM101 TraF, and in the TraF X-ray structure the corresponding Gly residue is positioned near an α-helical domain termed the antenna projection (AP), which is implicated in formation of the OM pore. A partial AP deletion mutation (ΔAP) also confers a Tra(+) Pil(-) phenotype; however, this mutation did not allow VirE2 surface exposure but instead allowed the release of pilin monomers or short oligomers to the milieu. We propose that (i) G272R disrupts a gating mechanism in the core chamber that regulates substrate passage across the OM and (ii) the G272R and ΔAP mutations block pilus production at distinct steps of the pilus biogenesis pathway.

Correction: Small is beautiful, but large is certified: A comparison between fisheries the Marine Stewardship Council (MSC) features in its promotional materials and MSC-certified fisheries.

[This corrects the article DOI: 10.1371/journal.pone.0231073.].

Functionalizing Cell-Free Systems with CRISPR-Associated Proteins: Application to RNA-Based Circuit Engineering.

Cell-free systems have become a compelling choice for the prototyping of synthetic circuits. Many robust protocols for preparing cell-free systems are now available along with toolboxes designed for a variety of applications. Thus far, the production of cell-free extracts has often been decoupled from the production of functionalized proteins. Here, we leveraged a recent protocol for producing an E. coli-based cell-free expression system with two CRISPR-associated proteins, Csy4 and dCas9, expressed prior to harvest. We found that pre-expression did not affect the resulting extract performance, and the final concentrations of the endonucleases matched the level required for synthetic circuit prototyping. We demonstrated the benefits and versatility of dCas9 and Csy4 through the use of RNA circuitry based on a combination of single guide RNAs, small transcriptional activator RNAs, and toehold switches. For instance, we show that Csy4 processing increased 4-fold the dynamic range of a previously published AND-logic gate. Additionally, blending the CRISPR-enhanced extracts enabled us to reduce leakage in a multiple inputs gate, and to extend the type of Boolean functions available for RNA-based circuits, such as NAND-logic. Finally, we reported the use of simultaneous transcriptional and translational reporters in our RNA-based circuits. In particular, the AND-gate mRNA and protein levels were able to be independently monitored in response to transcriptional and translational activators. We hope this work will facilitate the adoption of advanced processing tools for RNA-based circuit prototyping in a cell-free environment.

Resource allocation in transboundary tuna fisheries: A global analysis.

Resource allocation is a fundamental and challenging component of common pool resource governance, particularly transboundary fisheries. We highlight the growing importance of allocation in fisheries governance, comparing approaches of the five tuna Regional Fisheries Management Organizations (tRFMOs). We find all tRFMOs except one have defined resources for allocation and outlined principles to guide allocation based on equity, citizenship, and legitimacy. However, all fall short of applying these principles in assigning fish resources. Most tRFMOs rely on historical catch or effort, while equity principles rarely determine dedicated rights. Further, the current system of annual negotiations reduces certainty, trust, and transparency, counteracting many benefits asserted by rights-based management proponents. We suggest one means of gaining traction may be to shift conversations from allocative rights toward weighting of principles already identified by most tRFMOs. Incorporating principles into resource allocation remains a major opportunity, with important implications for current and future access to fish.

Small is beautiful, but large is certified: A comparison between fisheries the Marine Stewardship Council (MSC) features in its promotional materials and MSC-certified fisheries.

The Marine Stewardship Council (MSC) sets a standard by which sustainable fisheries can be assessed and eco-certified. It is one of the oldest and most well-known fisheries certifications, and an estimated 15% of global fish catch is MSC-certified. While the MSC is increasingly recognized by decision-makers as an indicator for fishery success, it is also criticized for weak standards and overly-lenient third-party certifiers. This gap between the standard's reputation and its actual implementation could be a result of how the MSC markets and promotes its brand. Here we classify MSC-certified fisheries by gear type (i.e. active vs. passive) as well as by length of the vessels involved (i.e. large scale vs. small scale; with the division between the two occurring at 12 m in overall length). We compared the MSC-certified fisheries (until 31 December 2017) to 399 photographs the MSC used in promotional materials since 2009. Results show that fisheries involving small-scale vessels and passive gears were disproportionately represented in promotional materials: 64% of promotional photographs were of passive gears, although only 40% of MSC-certified fisheries and 17% of the overall catch were caught by passive gears from 2009-2017. Similarly, 49% of the photographs featured small-scale vessels, although just 20% of MSC-certified fisheries and 7% of the overall MSC-certified catch used small-scale vessels from 2009 to 2017. The MSC disproportionately features photographs of small-scale fisheries although the catch it certifies is overwhelmingly from industrial fisheries.

Benchmarking data of the Fair Trade USA Capture Fisheries Standard and the Marine Stewardship Council Fisheries Standard against the Food and Agricultural Organization's Voluntary Guidelines for Securing Sustainable Small-Scale Fisheries.

This paper presents data associated with the benchmarking of the Fair Trade USA (FT USA) Capture Fisheries Standard and the Marine Stewardship Council (MSC) Fisheries Standard against the Food and Agriculture Organization's Voluntary Guidelines for Securing Sustainable Small-Scale Fisheries in the Context of Food Security and Poverty Eradiation (FAO Voluntary Guidelines). Benchmarking was used to determine the extent to which these standards, which promote sustainability in different ways, align with the FAO Voluntary Guidelines. The data represent a comprehensive analysis of these standards and are useful for beginning to understand the appropriateness of these standards for small-scale fisheries in developing regions of the world. For further interpretation and discussion please see "A tale of two standards: A case study of the Fair Trade USA certified Maluku handline yellowfin tuna (Thunnus albacares) fishery" [1].

Katanin catalyzes microtubule depolymerization independently of tubulin C-terminal tails.

Microtubule network remodeling is an essential process for cell development, maintenance, cell division, and motility. Microtubule-severing enzymes are key players in the remodeling of the microtubule network; however, there are still open questions about their fundamental biochemical and biophysical mechanisms. Here, we explored the ability of the microtubule-severing enzyme katanin to depolymerize stabilized microtubules. Interestingly, we found that the tubulin C-terminal tail (CTT), which is required for severing, is not required for katanin-catalyzed depolymerization. We also found that the depolymerization of microtubules lacking the CTT does not require ATP or katanin's ATPase activity, although the ATP turnover enhanced depolymerization. We also observed that the depolymerization rate depended on the katanin concentration and was best described by a hyperbolic function. Finally, we demonstrate that katanin can bind to filaments that lack the CTT, contrary to previous reports. The results of our work indicate that microtubule depolymerization likely involves a mechanism in which binding, but not enzymatic activity, is required for tubulin dimer removal from the filament ends.

Benefits of the Paris Agreement to ocean life, economies, and people.

The Paris Agreement aims to mitigate the potential impacts of climate change on ecological and social systems. Using an ensemble of climate-marine ecosystem and economic models, we explore the effects of implementing the Agreement on fish, fishers, and seafood consumers worldwide. We find that implementing the Agreement could protect millions of metric tons in annual worldwide catch of top revenue-generating fish species, as well as billions of dollars annually of fishers' revenues, seafood workers' income, and household seafood expenditure. Further, our analysis predicts that 75% of maritime countries would benefit from this protection, and that ~90% of this protected catch would occur within the territorial waters of developing countries. Thus, implementing the Paris Agreement could prove to be crucial for the future of the world's ocean ecosystems and economies.

When caretaking competes with care giving: a qualitative study of full-time working mothers who are nurse managers.

AIM: The purpose of this study was to explore the motivations and stresses associated with full-time working mothers who practice as nurse managers. BACKGROUND: Full-time work outside the home for mothers has been recognized as a circumstance which may present certain benefits and risks to family life. Nursing management is recognized as a high-stress occupation, which may be filled by mothers who work full time. Little is known about the specific needs and stresses of full-time nurse managers who are caring for children at home. METHODS: In-depth interviews were conducted with 13 mothers who worked as nurse managers. RESULTS: Participants expressed challenges in several areas including balancing/separating work and home, self-imposed advancement inhibitions, and constant giving. Challenges were offset by assets, which included complimentary roles, health insurance, added income, and professional and personal fulfilment. CONCLUSION: Participants 'wanted it all', including the conveniences of part-time employment and the benefits of full-time employment. IMPLICATIONS FOR NURSING MANAGEMENT: Full-time nurse managers with children at home experience unique tensions which characterize their work and home environments. Employers may assist nurses by adopting flexible scheduling, educational and child-care support and assistance in negotiating work and home roles.

High seas fisheries play a negligible role in addressing global food security.

Recent international negotiations have highlighted the need to protect marine diversity on the high seas-the ocean area beyond national jurisdiction. However, restricting fishing access on the high seas raises many concerns, including how such restrictions would affect food security. We analyze high seas catches and trade data to determine the contribution of the high seas catch to global seafood production, the main species caught on the high seas, and the primary markets where these species are sold. By volume, the total catch from the high seas accounts for 4.2% of annual marine capture fisheries production and 2.4% of total seafood production, including freshwater fisheries and aquaculture. Thirty-nine fish and invertebrate species account for 99.5% of the high seas targeted catch, but only one species, Antarctic toothfish, is caught exclusively on the high seas. The remaining catch, which is caught both on the high seas and in national jurisdictions, is made up primarily of tunas, billfishes, small pelagic fishes, pelagic squids, toothfish, and krill. Most high seas species are destined for upscale food and supplement markets in developed, food-secure countries, such as Japan, the European Union, and the United States, suggesting that, in aggregate, high seas fisheries play a negligible role in ensuring global food security.

The kinetoplastid kinetochore protein KKT4 is an unconventional microtubule tip-coupling protein.

Kinetochores are multiprotein machines that drive chromosome segregation by maintaining persistent, load-bearing linkages between chromosomes and dynamic microtubule tips. Kinetochores in commonly studied eukaryotes bind microtubules through widely conserved components like the Ndc80 complex. However, in evolutionarily divergent kinetoplastid species such as Trypanosoma brucei, which causes sleeping sickness, the kinetochores assemble from a unique set of proteins lacking homology to any known microtubule-binding domains. Here, we show that the T. brucei kinetochore protein KKT4 binds directly to microtubules and maintains load-bearing attachments to both growing and shortening microtubule tips. The protein localizes both to kinetochores and to spindle microtubules in vivo, and its depletion causes defects in chromosome segregation. We define a microtubule-binding domain within KKT4 and identify several charged residues important for its microtubule-binding activity. Thus, despite its lack of significant similarity to other known microtubule-binding proteins, KKT4 has key functions required for driving chromosome segregation. We propose that it represents a primary element of the kinetochore-microtubule interface in kinetoplastids.