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Effect of centrifugation of stallion semen through a low density colloid prior to freezing on sperm cryosurvival
Get PDFSperm quality is adversely affected by cryopreservation due to the increased production of reactive oxygen species, which affects the integrity of sperm membranes, motility, and DNA fragmentation. Three methods for removing seminal plasma, washing (centrifuging extended semen at 800× g for 10 min) and Single Layer Centrifugation with high or low density Equicoll, were used to prepare 29 ejaculates from ten stallions for freezing. Sperm quality parameters (kinematics, plasma membrane integrity, superoxide and hydrogen peroxide production, mitochondrial membrane potential, and DNA fragmentation) were evaluated before and after freezing using kinematic and flow cytometric analysis. The parameters for fresh samples were within the normal range for stallion semen but were lower after thawing. There were few differences between the three preparation methods. Interestingly, DNA fragmentation was affected most by the sperm preparation method, being lowest for SLC through high density Equicoll, although SLC through low density Equicoll was effective for some stallions. Some differences were observed in the proportions of live or dead spermatozoa positive for hydrogen peroxide. In conclusion, all of these methods would be suitable for the preparation of semen prior to cryopreservation, but Single Layer Centrifugation through high density Equicoll was the most effective in removing spermatozoa with damaged DNA
Effects of leaf ages, altitude and clone types on nutrient elements and antioxidant activity of tea (Camellia sinensis L. (O) Kuntze) in tropical conditions
Get PDFTea is a globally popular heritage beverage consumed by over three billion people. The unique taste and health benefits of tea are linked to its nutrient composition and antioxidant activity (AOA). As a plant species, tea’s nutrient elements and AOA vary based on season, altitude, clone type and leaf age. This study examined the nutrient composition and AOA of young and mature tea leaves from four clones (BC1248, TRI2024, AT53 and TV9) grown at different altitudes under tropical conditions in Malaysia. The results demonstrated that altitude and clone type significantly influenced (p 0.05). On the other hand, foliar nutrient elements varied significantly among lowland tea clones, except for N and Ca. The highest AOA was recorded in young tea leaves of clone BC1248 at the lowland plantations, with total polyphenol contents (TPC), 2,2-diphenyl-1-picrylhydrazylradical (DPPH IC50), and ferric reducing antioxidant power (FRAP) values of 19.60 ± 0.15 mg GAE/g, 50.70 ± 1.86 µg/mL, 2.10 ± 0.14 mM Fe (II)/g, respectively. The DPPH IC50 and FRAP varied significantly (
Governance challenges and opportunities for multifunctional marine and coastal landscapes: A comparative case study of Namdo national park and Namdo biosphere reserve in Sweden
Get PDFAgainst a backdrop of increasing pressures from biodiversity loss, climate change and competing stakeholder interests, this paper examines factors influencing the implementation of marine and coastal governance approaches and their implications for achieving multifunctional marine and coastal landscapes. Based on a comparative case study of the temporally and spatially overlapping implementation of a state-driven National Park (NP) and a community-led Biosphere Reserve (BR) in the Namdo Archipelago, Sweden, we conducted semi-structured interviews with differently positioned stakeholders to explore the dynamics shaping these initiatives. Deploying the Institutional Analysis and Development framework as an analytical framework in conjunction with a complex systems approach, the study identifies the interplay of key institutional and socio-ecological factors driving implementation processes and influencing outcomes. Results concerning the NP implementation reveal persistent disagreements between local residents and authorities, due to rigid institutional structures, limited integration of local knowledge, poor communication and competing priorities. In contrast, the BR approach is generally viewed more positively, attributed to its flexible governance and proactive integration of local socioeconomic and cultural values. This study highlights the importance of adaptive, inclusive governance that can address the trade-offs and synergies inherent in multifunctional sustainability efforts in coastal regions. By combining the stability and enforcement capabilities of the NP model with the flexibility and inclusivity of the BR approach, the paper suggests that a hybrid governance model could better balance ecological, social and economic objectives. It advocates for marine governance structures that prioritise inclusive decision-making and the integration of diverse values to better align ecological and community goals
Recovery of uranium from seawaters by ultra/nano filtration assisted by complexation
Get PDFUranium extraction from unconventional sources such as seawater is an important complementary source for nuclear fuel production. A common method for separating ions in aqueous solutions is ultra/nano filtration (UF/ NF), which employs both electrical and steric effects. While commercial inorganic UF/NF membranes have been used to separate uranium from other salts in natural or synthetic seawater, the high ionic strength of seawater tends to reduce the electrical effect. To overcome this, hydrophilic polymers with high selectivity towards uranium have been introduced into seawater to assist the filtration by complexation. This allows uranium to be rejected by the steric effect while allowing other metal ions to pass through the membrane. The performance of different hydrophilic polymers containing complexing functional groups, including alendronic acid, bis(phosphonic acid), and catechol, was evaluated to assist in the filtration process to separate uranium from other competitive metal ions (Na, K, Ca, Mg). The results show that two hydrophilic polymers, based on N-acryl-oylalendronate, demonstrate the best performance for the separation of uranium, achieving a sorption capacity of over 200 mg U/g polymer and an extremely high separation factor of U to salts (SF(U/Na) > 6000 for a (poly (NAM-co-ALNAm)). By using filtration assisted by complexation with polymers, uranium can be effectively rejected while maintaining low rejections for other salts in high salinity seawater of at 35 g L-1. Uranium can be released from the complex by spiking the seawater by concentrated nitric acid or sulfuric acid. These laboratory-scale filtration experiments have significant industrial applications for the recovery uranium from seawater
Haplotype structure and heterozygosity around the fragile foal syndrome variant in Swedish Warmblod horses
Get PDFFragile foal syndrome (FFS) is a disease caused by a recessive lethal missense mutation in the PLOD1 gene located on ECA2. Despite its harmful effect, a relatively high frequency of FFS carriers was observed in Warmblood breeds spanning from 7.4% in a random sample of Swedish Warmblood breed to 17% in the Hanoverian and Danish Warmblood, indicating potential heterozygous advantage. Balancing selection can be further studied based on haplotype blocks and via detection of heterozygosity-rich region (ROHet) around the target of selection. In this study we evaluated the presence of haplotype blocks and ROHet on ECA2 in 380 Swedish Warmblood horses. We compared the results of ROHet with the rest of the genome. On average, 11.7 heterozygosity rich regions were identified per horse on ECA2, with no significant difference in numbers and length compared to what was found in other chromosomes. A unique haplotype block containing 28 markers was found in the FFS haplotype, while there were several haplotype blocks in the non-carrier haplotype. This unique haplotype block mostly spanned the region upstream of the PLOD1 gene and included the MFN2 gene. The presence of this extended haplotype, shared by multiple individuals and including both the FFS variant and the MFN2 gene, suggests that this region may be under selection. While we did not find a clear heterozygosity-rich region around the FFS variant, the extended haplotype may reflect either a signature of balancing selection or linkage disequilibrium with a positively selected variant in MFN2, PLOD1, or nearby loci
Abiotic stress responses in forage crops and grasses: the role of secondary metabolites and biotechnological interventions
Get PDFForage crops and grasses play crucial roles in global agriculture, serving as primary sources of livestock feed. However, various abiotic stresses, such as drought, salinity, extreme temperatures, and heavy metals, frequently challenge their productivity, quality, and resilience. In response to these stressors, plants activate defense mechanisms, including the production of secondary metabolites (SMs). This review exclusively examines the diverse impacts of abiotic stresses on forage crops and grasses' physiological processes, growth, development, yield, and quality. We delve into the synthesis, types, and role of SMs in mediating stress responses, conferring adaptation and resilience to adverse environmental conditions in forage crops and grasses. Furthermore, we examine the regulatory mechanisms governing SM production in response to abiotic stress. This is crucial for developing strategies to enhance stress tolerance and improve forage productivity and quality. Finally, the review discusses emerging biotechnological interventions for improving forage crop performance under abiotic stress. Different omics technologies, gene editing, and pathway engineering offer promising avenues that enable the precise manipulation of key regulatory genes and metabolic pathways, with enhanced SM biosynthesis to engineer resilient crops tailored to specific environmental challenges. This review obtains a strong correlation of SMs with improving fodder and forage crop tolerance to varying degrees of stresses by regulating antioxidant activity, osmotic homeostasis, and membrane stability, ultimately enhancing plant viability, productivity, and quality under diverse stress conditions. Further, unraveling the intricate interplay between abiotic stresses, SMs, and biotechnological interventions is pivotal for advancing forage crop resilience and ensuring global food security amid changing environmental conditions
Forest structure, timber species regeneration, and timber volume dynamics along a logging gradient in a lowland tropical rainforest in Africa: Implications for biodiversity conservation and sustainable timber management
Get PDFTimber production, cutting and extraction is impacting vast areas of tropical forests, highlighting the need for management strategies to promote sustainable recovery of logged forests. However, limited information is available on how logging and enrichment planting affect forest structure, commercial tree species, and timber volume recovery. In this study, we assessed the effects of timber cutting and extraction ("logging") on forest structure, regeneration of key timber species, and volume recovery across different logging intensities. We compared the effects of enrichment planting, initiated over 60 years ago, versus natural regeneration on timber volume recovery of Khaya anthotheca (Welw.) C.DC., a highly targeted species. We inventoried all live stems with a diameter at breast height (DBH) of >= 2 cm across 9 compartments using 45 plots of 0.5 ha each: heavily logged forests (25 plots, totaling 12.5 ha), lightly logged forests (15 plots, totaling 7.5 ha), and unlogged forest (5 plots, totaling 2.5 ha). Our results suggest that timber production has impacted on tree regeneration of harvested timber species such Entandrophragma species, Milicia excelsa (Welw.) C. Berg, Olea capensis L. subsp. welwitschii (Knobl.) Friis & Green and Ricinodendron heudelotii (Baill.) Heckel; Timber volume recovery of harvested species was 61.3% lower in heavily logged and 51.7% lower in lightly logged forests compared to unlogged forest. Stem density, basal area, and timber volume recovery of mahogany species were influenced by time since last logging. Notably, the compartment which was logged earlier in 1945 and enriched with K. anthotheca showed significantly higher stem density and timber volume of this species compared to logged forests without such enrichment. In conclusion, our study suggests that passive regeneration in Budongo's logged compartments has been inadequate for achieving timber volume recovery of high-value commercial species. If an economic assessment proves favorable we recommend further trials of enrichment planting of high-value timber species (Mahogany spp., Milicia excelsa, and Olea capensis) alongside fast-growing species (Maesopsis eminii Engl., Albizia spp.). As well as Reduced Impact Logging and broader species selection from classes II and III, to reduce damage and enhance timber yields in production forests
The flipside of hope discourse: avoiding accountability and assigning responsibility in sustainability transitions
Get PDFNowadays, environmental scholars and practitioners largely embrace the importance of characterizing environmental communication via messages of hope. Overall, research on hope and communication suggests that strategically designed hope messages can foster pro-environmental attitudes and behaviors. However, such research tends to focus solely on the instrumental aspects of communication. Conversely, research emphasizing the social function of hope considers it a discursive phenomenon that people actively use in interactions to perform different social actions. Accountability, responsibility, and agency are central features of hope discourse, and it is important that they are addressed in environmental communication and management to move from good intentions and high ambitions to action. In this paper, we examine how these issues are managed in inspirational meetings that promote the transition to a circular economy, one that is largely regarded as a promising strategy for solving contemporary environmental issues. We adopt the methodology of discursive psychology and analyze how the hope discourse that dominates these meetings is constructed, situated, and oriented toward action. We find that meeting participants use hope discourse to not only downplay problems and challenges but also avoid issues of accountability for claims that can be considered negative or pessimistic. Hope discourse can also be used to assign responsibility to others as well as to renounce it personally, thereby externalizing responsibility and construing hope as a passive act. Furthermore, hope discourse enables participants to portray themselves as active and agentic by claiming responsibility and making commitments to realize a circular economy, while bringing about change. However, such commitments tend to be non-specific, and participants rarely clarify the extent of their responsibility or the actions they encompass. We conclude that hope discourse relates to accountability, responsibility, and agency in ambiguous and variable ways; therefore, environmental scholars and practitioners should critically engage with such a discourse by identifying when it enables the joint exploration of problems and challenges and when it closes down
Marker-assisted selection for combining stem rust and stripe rust resistance in wheat using rye derived genes
Get PDFStem rust and stripe rust are among the most devastating wheat (Triticum aestivum L.) diseases globally. This study used marker-assisted selection to incorporate two resistance genes, Sr59 and YrSLU (where SLU is Swedish University of Agriculture Science), derived from rye (Secale cereale L.), into elite wheat backgrounds. The initial cross combined Sr59 from line TA5095 and YrSLU from line #392 using kompetitive allele-specific PCR (KASP) markers. A three-step crossing scheme integrated these genes into adapted wheat lines. F1 plants were crossed with the commercial wheat variety Linkert, followed by top-crossing with Navruz. Selected progeny were double top-crossed with an elite breeding line, SLU-Elite, producing generations TT1 to TT4 through self-pollination. Plants containing Sr59 and YrSLU were identified at each generation using KASP markers. Field trials in the TT5 generation assessed agronomic performance and increased seed production. In the TT6 and TT7 generations, seedling resistance tests confirmed that Sr59 conferred robust resistance to Pgt races TTKSK, TTRTF, and TTTTF. YrSLU provided resistance against Pst races Psts10, Psts16, Psts7, and Psts13. However, TT6 remained segregated for resistance to Pst race Psts7 (Warrior). By TT7, consistent resistance to Psts7 was observed in pyramided lines. This study shows the effectiveness of crossing schemes integrating rye-derived resistance genes into wheat. KASP markers enabled precise selection, combining enhanced disease resistance with elite agronomic traits. These findings demonstrate a practical approach to improving wheat's resilience to rust diseases through targeted breeding
Putative neural and endocrine control of thermal acclimation in fish
Get PDFFishes can acclimate to a range of temperatures. However, the signalling factors controlling thermal acclimation are not well understood. Here, in two experiments, we examined the putative roles of plasma-borne factors (e.g. hormones) and skin thermoreception in the acclimation process. In experiment 1, 16 degrees C-acclimated Atlantic cod (Gadus morhua) were subjected to a transfusion treatment by injecting plasma from 8 degrees C (cold), 16 degrees C (control) or 21 degrees C (warm) acclimated cod, 10 times over four days. Plasma was collected from donor cod that were 24 h into their acclimation. In experiment 2, 16 degrees C-acclimated goldsinny wrasse (Ctenolabrus rupestris) were exposed to an immersion treatment consisting of 10 s immersions in an 8 degrees C (cold), 16 degrees C (control) or 24 degrees C (warm) water bath, repeated five times daily for five days. These brief immersions allowed for changes to skin temperature but not deeper tissues. Following these treatments, we measured the critical thermal maximum (CTmax) of all fish and the standard metabolic rate (SMR) in cod. Neither the immersions nor transfusions affected fish CTmax. However, the SMR was elevated in cod receiving plasma from cold-acclimated donors, suggesting that circulating molecules transferred from donors had initiated metabolic compensation in recipients. Thyroid hormone plasma levels were not different amongst acclimated donors and thus appear not to have been involved in the metabolic compensation. Our experiments found no evidence that brief, repeated cutaneous exposures to temperature changes can trigger acclimation, but do demonstrate a potential role of haematological endocrine control in metabolic acclimation, although further experiments will be required to investigate this process.Little is known about the mechanisms controlling thermal acclimation in fish. We explored the roles of plasma-borne factors and skin thermoreception using experiments in Atlantic cod and goldsinny wrasse. Our findings suggest that metabolic acclimation to the cold is under endocrine control, while skin thermosensation does not trigger thermal acclimation