Effect of alternating day and night temperature on short day-induced bud set and subsequent bud burst in long days in Norway spruce

Young seedlings of the conifer Norway spruce exhibit short day (SD)-induced cessation of apical growth and bud set. Although different, constant temperatures under SD are known to modulate timing of bud set and depth of dormancy with development of deeper dormancy under higher compared to lower temperature, systematic studies of effects of alternating day (DT) and night temperatures (NT) are limited. To shed light on this, seedlings of different provenances of Norway spruce were exposed to a wide range of DT-NT combinations during bud development, followed by transfer to forcing conditions of long days (LD) and 18°C, directly or after different periods of chilling. Although no specific effect of alternating DT/NT was found, the results demonstrate that the effects of DT under SD on bud set and subsequent bud break are significantly modified by NT in a complex way. The effects on bud break persisted after chilling. Since time to bud set correlated with the daily mean temperature under SD at DTs of 18 and 21°C, but not a DT of 15°C, time to bud set apparently also depend on the specific DT, implying that the effect of NT depends on the actual DT. Although higher temperature under SD generally results in later bud break after transfer to forcing conditions, the fastest bud flush was observed at intermediate NTs. This might be due to a bud break-hastening chilling effect of intermediate compared to higher temperatures, and delayed bud development to a stage where bud burst can occur, under lower temperatures. Also, time to bud burst in un-chilled seedlings decreased with increasing SD-duration, suggesting that bud development must reach a certain stage before the processes leading to bud burst are initiated. The present results also indicate that low temperature during bud development had a larger effect on the most southern compared to the most northern provenance studied. Decreasing time to bud burst was observed with increasing northern latitude of origin in un-chilled as well as chilled plants. In conclusion, being a highly temperature-dependent process, bud development is strongly delayed by low temperature, and the effects of DT is significantly modified by NT in a complex manner

Growth, seed development and genetic analysis in wild type and Def mutant of Pisum sativum L

<p>Abstract</p> <p>Background</p> <p>The <it>def </it>mutant pea (<it>Pisum sativum </it>L) showed non-abscission of seeds from the funicule. Here we present data on seed development and growth pattern and their relationship in predicting this particular trait in wild type and mutant lines as well as the inheritance pattern of the <it>def </it>allele in F₂and F₃populations.</p> <p>Findings</p> <p>Pod length and seed fresh weight increase with fruit maturity and this may affect the abscission event in pea seeds. However, the seed position in either the distal and proximal ends of the pod did not show any difference. The growth factors of seed fresh weight (FW), width of funicles (WFN), seed width (SW) and seed height (SH) were highly correlated and their relationships were determined in both wild type and <it>def </it>mutant peas. The coefficient of determination <it>R</it>²values for the relationship between WFN and FW, SW and SH and their various interactions were higher for the <it>def </it>dwarf type. Stepwise multiple regression analysis showed that variation of WFN was associated with SH and SW. Pearson's chi square analysis revealed that the inheritance and segregation of the <it>Def </it>locus in 3:1 ratio was significant in two F₂populations. Structural analysis of the F3 population was used to confirm the inheritance status of the <it>Def </it>locus in F₂heterozygote plants.</p> <p>Conclusions</p> <p>This study investigated the inheritance of the presence or absence of the <it>Def </it>allele, controlling the presence of an abscission zone (AZ) or an abscission-less zone (ALZ) forming in wild type and mutant lines respectively. The single major gene (<it>Def</it>) controlling this phenotype was monogenic and <it>def </it>mutants were characterized and controlled by the homozygous recessive <it>def </it>allele that showed no palisade layers in the hilum region of the seed coat.</p

Long term effects of ionising radiation in the Chernobyl Exclusion zone on DNA integrity and chemical defence systems of Scots pine (Pinus sylvestris)

The Chernobyl Nuclear Power Plant (ChNPP) accident in 1986 resulted in extremely high levels of acute ionising radiation, that killed or damaged Scots pine (Pinus sylvestris) trees in the surrounding areas. Dead trees were cleared and buried, and new plantations established a few years later. Today, more than three decades later, gamma and beta-radiation near the ChNPP is still elevated compared with ambient levels but have decreased by a factor of 300 and 100, respectively. In the present work, Scots pine-trees growing at High (220 μGy h−1), Medium (11 μGy h−1), and Low (0.2 μGy h−1) total (internal + external) dose rates of chronically elevated ionising radiation in the Chernobyl Exclusion zone were investigated with respect to possible damage to DNA, cells and organelles, as well as potentially increased levels of phenolic and terpenoid antioxidants. Scots pine from the High and Medium radiation sites had elevated levels of DNA damage in shoot tips and needles as shown by the COMET assay, as well as increased numbers of resin ducts and subcellular abnormalities in needles. Needles from the High radiation site showed elevated levels of monoterpenes and condensed tannins compared with those from the other sites. In conclusion, more than three decades after the ChNPP accident substantial DNA damage and (sub)cellular effects, but also mobilisation of stress-protective substances possessing antioxidant activity were observed in Scots pine trees growing at elevated levels of ionising radiation. This demonstrates that the radiation levels in the Red Forest still significantly impact the plant community.publishedVersio

Comparison of lower limb muscle activation according to horizontal whole-body vibration frequency and knee angle

Whole-body vibration refers to an exercise that stimulates the muscles, using a vibration with an amplitude and power, however, there are few studies that have dealt with fundamental questions such as optimal frequency or body position. This study aims to compare lower limb activation, according to horizontal whole-body vibration frequency and knee flexion angle, in healthy adults. Using 18 healthy adults aged 21–30, this study measured and analysed the activities of the vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GCM) muscles, for different horizontal whole-body vibration frequencies (0 Hz, 2 Hz, and 4 Hz) and knee flexion angles (0°, 30°, and 60°), using surface electromyography (sEMG). There was a statistically significant increase in lower limb muscle activation according to horizontal whole-body vibration frequency and knee flexion angle: comparing muscle activation with frequency, the muscle activation of VL, BF, TA, and GCM increased with increase in frequency (p<0.05). The muscle activation of VL and TA increased with increase in knee flexion angle (p<0.05). In this study, it was observed that for whole-body vibration provided in a horizontal direction, larger the frequency and higher the knee flexion angle, greater the lower limb activation

Integrative assessment of low-dose gamma radiation effects on <i>Daphnia magna</i> reproduction: Toxicity pathway assembly and AOP development

High energy gamma radiation is potentially hazardous to organisms, including aquatic invertebrates. Although extensively studied in a number of invertebrate species, knowledge on effects induced by gamma radiation is to a large extent limited to the induction of oxidative stress and DNA damage at the molecular/cellular level, or survival, growth and reproduction at the organismal level. As the knowledge of causal relationships between effects occurring at different levels of biological organization is scarce, the ability to provide mechanistic explanation for observed adverse effects is limited, and thus development of Adverse Outcome Pathways (AOPs) and larger scale implementation into next generation hazard and risk predictions is restricted. The present study was therefore conducted to assess the effects of high-energy gamma radiation from cobalt-60 across multiple levels of biological organization (i.e., molecular, cellular, tissue, organ and individual) and characterize the major toxicity pathways leading to impaired reproduction in the model freshwater crustacean Daphnia magna (water flea). Following gamma exposure, a number of bioassays were integrated to measure relevant toxicological endpoints such as gene expression, reactive oxygen species (ROS), lipid peroxidation (LPO), neutral lipid storage, adenosine triphosphate (ATP) content, apoptosis, ovary histology and reproduction. A non-monotonic pattern was consistently observed across the levels of biological organization, albeit with some variation at the lower end of the dose-rate scale, indicating a complex response to radiation doses. By integrating results from different bioassays, a novel pathway network describing the key toxicity pathways involved in the reproductive effects of gamma radiation were proposed, such as DNA damage-oocyte apoptosis pathway, LPO-ATP depletion pathway, calcium influx-endocrine disruption pathway and DNA hypermethylation pathway. Three novel AOPs were proposed for oxidative stressor-mediated excessive ROS formation leading to reproductive effect, and thus introducing the world's first AOPs for non-chemical stressors in aquatic invertebrates.publishedVersio

Stabilized Liposomes Transdermal Patch for Loaded Antioxidants Skin Therapy

In the body, skin acts as protective barrier insulating organs from physical, chemical or biological damage. Skin aging triggered by sun’s ultraviolet rays, and pollution decrease its protective barrier and physiological functional properties. The cosmetic industry and dermatologist hunt for effective therapeutic technologies to slow skin aging. Skin anti aging therapy include the radiofrequency technology that use the thermal energy application onto the skin to induce dermal and epidermal remodeling, which triggers regeneration. This is an expensive therapeutic technology, and there still remains the use of anti-aging products with antioxidants, which protect the skin from free radical that induce skin aging. Numerous antioxidants exist, —e.g. retinol, lecithin, — however there remains a challenge to deliver these compounds the epidermis to afford skin protection. In addition, antioxidants are environmentally unstable, and lose their potency with exposure. As such, approach to mitigate the instability and a delivery vehicle is the use of liposome technology. Liposome is a microsphere with an aqueous center and a lipid exterior, a dual structure that affords skin penetration. As a proof concept, we have developed polyhydroxylated fatty acid (polyol) liposome and used it to encapsulate a model antiaging agent. The polylol liposomes was compared with lecithin based liposomes for controlled release on the anti-aging agent. Towards a fabrication of a dermatologist usable device, we have demonstrated a prototype voltage responsive biobased transdermal patch impregnated with antioxidant loaded liposomes, with controlled release of the antiaging agent triggered by disruption of the liposomes by a mild voltage application. Discipline: Chemistry Faculty Mentor: Dr. Samuel Mug

De novo Development of a Quantitative Adverse Outcome Pathway (qAOP) Network for Ultraviolet B (UVB) Radiation Using Targeted Laboratory Tests and Automated Data Mining

Ultraviolet B (UVB) radiation is a natural non-chemical stressor posing potential hazards to organisms such as planktonic crustaceans. The present study was conducted to revisit the lethal effects of UVB on crustaceans, generate new experimental evidence to fill in knowledge gaps, and develop novel quantitative Adverse Outcome Pathways (qAOPs) for UVB. A combination of laboratory and computational approaches were deployed to achieve the goals. For targeted laboratory tests, Daphnia magna was used as a prototype and exposed to a gradient of artificial UVB. Targeted bioassays were used to quantify the effects of UVB at multiple levels of biological organization. A toxicity pathway network was assembled based on the new experimental evidence and previously published data extracted using a novel computational tool, the NIVA Risk Assessment Database (NIVA RAdb). A network of AOPs was developed and weight of evidence assessed based on a combination of the current and existing data. In addition, quantitative key event relationships in the AOPs were developed by fitting the D. magna data to predefined models. A complete workflow for assembly and evaluation of qAOPs has been presented, which may serve as a good example for future de novo qAOP development for chemical and non-chemical stressors.publishedVersio

Stabilized Liposomes transdermal patch for loaded antioxidants skin therapy

As the largest organ in the body, skin acts a protective barrier insulating other organs from physical, chemical or biological damage. Skin aging triggered by sun’s ultraviolet rays, and pollution decrease its protective barrier and it’s physiological functional properties. The research hunt is on by cosmetic industry and dermatologist for effective therapeutic technologies to slow and reverse skin aging. Some modern skin antiaging therapy include the radiofrequency technology that work on the basis of thermal energy application onto the skin, believed to induce dermal and epidermal remodeling, which triggers regeneration.1,2 This is an expensive, public inaccessible therapeutic technology, and as such an economical approach remain the use of anti-aging skin care products with functional compounds called antioxidants, which protects the skin from free radical oxidative processes that induce skin aging. Numerous antioxidants exist, —e.g. retinol, algae oil, and lecithin, — however there remains a challenge for optimal transdermal delivery of these compounds the epidermis to afford effective skin protection. In addition, antioxidants are environmentally unstable, and lose their potency with exposure. As such, approach to mitigate both the instability and as a delivery vehicle is the use of liposome technology. Liposome is a (nano) or microsphere with an aqueous center pocket (houses the anti-aging agent) and a lipid exterior, a dual structure that affords skin penetration.3,4 As a proof concept, we have developed polyhydroxylated fatty acid (polyol) liposome and used it to encapsulate a model antiaging agent. The polylol liposomes was compared with lecithin based liposomes for controlled release on the anti-aging agent. Towards a fabrication of a dermatologist usable device, we have demonstrated a prototype voltage responsive biobased transdermal patch impregnated with antioxidant loaded liposomes, with controlled release of the antiaging agent triggered by disruption of the liposomes by a mild voltage application. Our presentation, will showcase the developed prototype. &nbsp; Reference &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Deirdre, C.; Laura, L.; Nazanin, Saedi. Semin Cutan Med Surg. 2017. 36. 138-147. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Krista, B.; Anderw, D.; Neil, S. J Cosmet Dermatol. 2018. 17. 61-65. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Makoto, T.; Dai, K.; Yonathan, A.; Kensaku, T.; Koji, W. Journal of Oleo Science. 2009, 12, 643-650. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Sala, M.; Diab, R.; Elaissari, A.; Fessi, A. Lipid Nanocarriers as Skin Drug Delivery Systems: Properties, Mechanisms of Skin Interactions and Medical Applications. Int J Pharm. 2018 Jan 15;535(1-2):1-17. *Indicates presente

Immunolocalization of pectic polysaccharides during abscission in pea seeds (Pisum sativum L.) and in abscission less def pea mutant seeds

BACKGROUND: In pea seeds (Pisum sativum L.), the presence of the Def locus determines abscission event between its funicle and the seed coat. Cell wall remodeling is a necessary condition for abscission of pea seed. The changes in cell wall components in wild type (WT) pea seed with Def loci showing seed abscission and in abscission less def mutant peas were studied to identify the factors determining abscission and non-abscission event. METHODS: Changes in pectic polysaccharides components were investigated in WT and def mutant pea seeds using immunolabeling techniques. Pectic monoclonal antibodies (1 → 4)-β-d-galactan (LM5), (1 → 5)-α-l-arabinan(LM6), partially de-methyl esterified homogalacturonan (HG) (JIM5) and methyl esterified HG (JIM7) were used for this study. RESULTS: Prior to abscission zone (AZ) development, galactan and arabinan reduced in the predestined AZ of the pea seed and disappeared during the abscission process. The AZ cells had partially de-methyl esterified HG while other areas had highly methyl esterified HG. A strong JIM5 labeling in the def mutant may be related to cell wall rigidity in the mature def mutants. In addition, the appearance of pectic epitopes in two F(3) populations resulting from cross between WT and def mutant parents was studied. As a result, we identified that homozygous dominant lines (Def/Def) showing abscission and homozygous recessive lines (def/def) showing non-abscission had similar immunolabeling pattern to their parents. However, the heterogeneous lines (Def/def) showed various immunolabeling pattern and the segregation pattern of the Def locus. CONCLUSIONS: Through the study of the complexity and variability of pectins in plant cell walls as well as understanding the segregation patterns of the Def locus using immunolabeling techniques, we conclude that cell wall remodeling occurs in the abscission process and de-methyl esterification may play a role in the non-abscission event in def mutant. Overall, this study contributes new insights into understanding the structural and architectural organization of the cell walls during abscission

Efficiency of enhanced oil recovery by injection of low-salinity water in barium-containing carbonate reservoirs

Abstract When low-salinity water containing sulfate ions is injected into carbonate reservoirs, rock dissolution and in situ precipitation occur, altering rock permeability and wettability. Particularly, when barium ions are present in formation water, they react chemically with $${\text{SO}}_{4}^{2 - }$$ SO42- , and BaSO4 is precipitated. These reactions can cause a serious impact on the efficiency of enhanced oil recovery (EOR). Therefore, the main purpose of this study was to identify EOR efficiency induced by low-salinity waterflooding (LSWF) when Ba2+ is present in carbonate reservoirs. From the experimental results, it was confirmed that the permeability calculated by the measured pressure difference was improved because of rock dissolution predominating over in situ precipitation for the case of low Ba2+ concentrations. In the analysis of wettability alteration through the measurements of relative permeabilities before and after LSWF, the higher Ba2+ concentration case consumed more $${\text{SO}}_{4}^{2 - }$$ SO42- in precipitating the BaSO4, resulting in weaker wettability alteration due to the reduction of sulfate activity. These phenomena ultimately influenced EOR efficiency, i.e., the oil recovery was greater for the lower Ba2+ concentration