Selection Among and Within S1 Lines of Maize on S2 Line and Testcross Performance

Most maize (Zea mays L.) breeders practice visual selection among lines during inbreeding, but may not be certain of the effectiveness of such selection. Visual selection among and within 1,636 S1 lines of maize derived from \u27Lancaster Composite\u27 was used to select 200 S2 lines, and a random set of 200 S2 lines also was developed. Yield trials of the 400 S2 lines in three environments and their testcrosses to (B73 x B84) in four environments were conducted to determine whether visual selection was effective in choosing high-yielding and agronomically desirable lines with superior combining ability. Grain yield of the visually selected S1 lines (3.11 Mg ha-1) was significantly (P\u3c0.05) greater than that of the unselected lines (2.94 Mg ha-1), but there was no difference in testcross means. Visually selected S1 lines had slightly greater mean grain moisture and slightly less mean stalk lodging than unselected lines in individual environments. Testcrosses of visually selected lines had greater grain moisture and less stalk lodging than testcrosses of unselected lines in individual environments. Estimates of genetic variance, heritability, and gain from selection were not consistently affected by visual selection. Many superior S2 lines and testcrosses were unselected lines, showing that visual selection failed to identify many desirable genotypes. Our results suggest that visual selection should not be used to attempt to select the most superior genotypes, but should emphasize discarding of undesirable genotypes before yield testing

Post-harvest fisheries development: A guide to handling, preservation, processing, and quality

In the early 1980s, the Tropical Products Institute (a forerunner of NRI) published a two volume report entitled Fish Handling, Preservation and Processing in the Tropics. It was written to provide a basis for middle management training courses in government and industry in tropical developing countries. Over the years, the publication has been one of the most popular of NRI's series of technical and scientific reports; it has been reprinted on a number of occasions and distributed to thousands of people worldwide. The present book is an updated version of the original. It is designed to bring to a lay audience the basic concepts behind post-harvest fisheries science and technology, and to assist the non-specialist with decision making. Readers familiar with the previous publication will find that parts of this book have been extensively revised. Where possible, a list of suggested further reading has been included at the end of each chapter so that more details can be obtained if required. If readers have difficulty in obtaining these publications, or need further information, the fisheries group of NRI can be contacted for assistance

Fate specification and tissue-specific cell cycle control of the <i>Caenorhabditis elegans</i> intestine

Coordination between cell fate specification and cell cycle control in multicellular organisms is essential to regulate cell numbers in tissues and organs during development, and its failure may lead to oncogenesis. In mammalian cells, as part of a general cell cycle checkpoint mechanism, the F-box protein β-transducin repeat-containing protein (β-TrCP) and the Skp1/Cul1/F-box complex control the periodic cell cycle fluctuations in abundance of the CDC25A and B phosphatases. Here, we find that the Caenorhabditis elegans β-TrCP orthologue LIN-23 regulates a progressive decline of CDC-25.1 abundance over several embryonic cell cycles and specifies cell number of one tissue, the embryonic intestine. The negative regulation of CDC-25.1 abundance by LIN-23 may be developmentally controlled because CDC-25.1 accumulates over time within the developing germline, where LIN-23 is also present. Concurrent with the destabilization of CDC-25.1, LIN-23 displays a spatially dynamic behavior in the embryo, periodically entering a nuclear compartment where CDC-25.1 is abundant

Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs.

OBJECTIVES: Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. METHODS: The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. RESULTS: All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. CONCLUSIONS: TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporter

Developing UAV monitoring of South Georgia and the South Sandwich Islands’ iconic land-based marine predators

Many remote islands present barriers to effective wildlife monitoring in terms of challenging terrain and frequency of visits. The sub-Antarctic islands of South Georgia and the South Sandwich Islands are home to globally significant populations of seabirds and marine mammals. South Georgia hosts the largest breeding populations of Antarctic fur seals, southern elephant seals and king penguins as well as significant populations of wandering, black-browed and grey-headed albatross. The island also holds important populations of macaroni and gentoo penguins. The South Sandwich Islands host the world’s largest colony of chinstrap penguins in addition to major populations of Adélie and macaroni penguins. A marine protected area was created around these islands in 2012 but monitoring populations of marine predators remains a challenge, particularly as these species breed over large areas in remote and often inaccessible locations. During the 2019/20 austral summer, we trialed the use of an unoccupied aerial vehicle (UAV; drone) to monitor populations of seals, penguins and albatross and here we report our initial findings, including considerations about the advantages and limitations of the methodology. Three extensive southern elephant seal breeding sites were surveyed with complete counts made around the peak pupping date, two of these sites were last surveyed 24 years ago. A total of nine islands, historically recorded as breeding sites for wandering albatross, were surveyed with 144 fledglings and 48 adults identified from the aerial imagery. The UAV was effective at surveying populations of penguins that nest on flat, open terrain, such as Adélie and chinstrap penguin colonies at the South Sandwich Islands, and an extensive king penguin colony on South Georgia, but proved ineffective for monitoring macaroni penguins nesting in tussock habitat on South Georgia as individuals were obscured or hidden by vegetation. Overall, we show that UAV surveys can allow regular and accurate monitoring of these important wildlife populations

Cytokinesis in bloodstream stage Trypanosoma brucei requires a family of katanins and spastin

Microtubule severing enzymes regulate microtubule dynamics in a wide range of organisms and are implicated in important cell cycle processes such as mitotic spindle assembly and disassembly, chromosome movement and cytokinesis. Here we explore the function of several microtubule severing enzyme homologues, the katanins (KAT80, KAT60a, KAT60b and KAT60c), spastin (SPA) and fidgetin (FID) in the bloodstream stage of the African trypanosome parasite, Trypanosoma brucei. The trypanosome cytoskeleton is microtubule based and remains assembled throughout the cell cycle, necessitating its remodelling during cytokinesis. Using RNA interference to deplete individual proteins, we show that the trypanosome katanin and spastin homologues are non-redundant and essential for bloodstream form proliferation. Further, cell cycle analysis revealed that these proteins play essential but discrete roles in cytokinesis. The KAT60 proteins each appear to be important during the early stages of cytokinesis, while downregulation of KAT80 specifically inhibited furrow ingression and SPA depletion prevented completion of abscission. In contrast, RNA interference of FID did not result in any discernible effects. We propose that the stable microtubule cytoskeleton of T. brucei necessitates the coordinated action of a family of katanins and spastin to bring about the cytoskeletal remodelling necessary to complete cell divisio

The TgsGP gene is essential for resistance to human serum in Trypanosoma brucei gambiense

Trypanosoma brucei gambiense causes 97% of all cases of African sleeping sickness, a fatal disease of sub-Saharan Africa. Most species of trypanosome, such as T. b. brucei, are unable to infect humans due to the trypanolytic serum protein apolipoprotein-L1 (APOL1) delivered via two trypanosome lytic factors (TLF-1 and TLF-2). Understanding how T. b. gambiense overcomes these factors and infects humans is of major importance in the fight against this disease. Previous work indicated that a failure to take up TLF-1 in T. b. gambiense contributes to resistance to TLF-1, although another mechanism is required to overcome TLF-2. Here, we have examined a T. b. gambiense specific gene, TgsGP, which had previously been suggested, but not shown, to be involved in serum resistance. We show that TgsGP is essential for resistance to lysis as deletion of TgsGP in T. b. gambiense renders the parasites sensitive to human serum and recombinant APOL1. Deletion of TgsGP in T. b. gambiense modified to uptake TLF-1 showed sensitivity to TLF-1, APOL1 and human serum. Reintroducing TgsGP into knockout parasite lines restored resistance. We conclude that TgsGP is essential for human serum resistance in T. b. gambiense

Evidence of pathogen-induced immunogenetic selection across the large geographic range of a wild seabird

Over evolutionary time,pathogen challenge shapes theimmunephenotype of the host tobetterrespondtoanincipient threat. The extent and direction of this selection pressure depend on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local pathogen threats in wild animals. The Gentoo penguin (Pygoscelis papua) is a species complex that lends itself to the study of immune adaptation becauseof its circumpolardistributionover a large latitudinal range, with littleornoadmixturebetweendifferent clades. Inthis study,we examine thediversity ina key family of innateimmunegenes-theToll-like receptors (TLRs)-across the range of the Gentoo penguin. The three TLRs that we investigated present varying levels of diversity, with TLR4 and TLR5 greatly exceeding the diversity of TLR7.We present evidence of positive selection in TLR4 and TLR5,which points to pathogen-driven adaptation to the local pathogen milieu. Finally, we demonstrate that two positively selected cosegregating sites in TLR5 are sufficient to alter the responsiveness of the receptor to its bacterial ligand, flagellin. Taken together, these results suggest that Gentoo penguins have experienced distinct pathogen-driven selection pressures in different environments, which may be important given the role of the Gentoo penguin as a sentinel species in some of the world's most rapidly changing environments.Fil: Levy, Hila. University of Oxford; Reino UnidoFil: Fiddaman, Steven R.. University of Oxford; Reino UnidoFil: Vianna, Juliana A.. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; ChileFil: Noll, Daly. Pontificia Universidad Católica de Chile; Chile. Universidad de Chile; ChileFil: Clucas, Gemma V.. Cornell University; Estados UnidosFil: Sidhu, Jasmine K.H.. University of Oxford; Reino UnidoFil: Polito, Michael J.. Louisiana State University; Estados UnidosFil: Bost, Charles A.. Centre D'etudes Biologiques de Chizé; FranciaFil: Phillips, Richard A.. British Antarctic Survey; Reino UnidoFil: Crofts, Sarah. Falklands Conservation; Reino UnidoFil: Miller, Gary D.. University of Western Australia; AustraliaFil: Pistorius, Pierre. Nelson Mandela University; SudáfricaFil: Bonnadonna, Francesco. Université de Montpellier; FranciaFil: Le Bohec, Celine. Université de Strasbourg; FranciaFil: Barbosa, Andres. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; EspañaFil: Trathan, Phil. British Antarctic Survey; Reino UnidoFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Frantz, Laurent A.F.. University of London; Reino UnidoFil: Hart, Tom. University of Oxford; Reino UnidoFil: Smith, Adrian L.. University of Oxford; Reino Unid

Paradoxical correlates of a facilitative parenting programme in prison—counter-productive intervention or first signs of responsible parenthood?

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Scandinavian Studies in Criminology and Crime Prevention on 07/04/2014, available online: doi: 10.1080/14043858.2014.898981Purpose. Parenting programmes are rarely part of prisoners’ rehabilitation, and evaluations of such programmes are lacking. Methods. The present mixed-methods study investigates the International Child Development Programme (ICDP) with 25 incarcerated fathers and a comparison group of 36 community fathers through questionnaires administered before and after parenting courses. Interviews with 20 incarcerated fathers were analysed using thematic analysis. Results. Before the course, the prison group self-reported better parenting skills and poorer psychosocial health than the comparison group. Both groups improved on parenting strategies. On several measures the comparison group improved, while the prison group revealed the same or lower scores. The incarcerated fathers described becoming more aware of their paternal role but also saw the course as emotionally challenging. Conclusions. Some of the self-reported scores of the prison participants related to parental skills and psychosocial health decreased from ‘before’ to ‘after’ ICDP sensitization, pointing to the possibility that the ICDP courses may have contributed to overcoming a ‘prisonization process’, where the prisoner identity overshadows the parental identity, by making them more aware of their parental responsibilities. Due to the emerging possibility of counter-productive influences, a randomized controlled study is needed in the future to ascertain the parenting and recidivism-related effects of this programme

Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs

Objectives Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. Methods The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. Results All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. Conclusions TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporte