F-box motif encoding genes as targets for the development of stress-tolerant traits in Saccharomyces cerevisiae

Stress tolerance is a useful trait actively sought by the bioprocess industry for biofactories dealing with bioconversion of varied raw materials or carbon sources. Fungal or yeast species are useful in bioconversion and are sustainable bioresources for biochemicals and biofuel production. Genetic manipulation strategies are in practice to enhance the tolerance against stress agents for the improved bioconversion process. In this review, we highlight the importance of the F-box motif encoding genes and their interactions in imparting the stress tolerance phenotype to the yeast species. The F-box motif proteins constitute a part of the SCF-E3 ligase complex and are involved in the recruitment, and ubiquitination, followed by degradation of the substrate proteins by the 26S proteasome. It highlights the current scenario on the F-box motif encoding genes and their interaction partners as targets for the stress tolerance phenotype in the yeast and plant species and their utility in the bioconversion processes.

Isolation and characterization of native Rhizobium from root nodules of raikia french bean growing area of Odisha-Supplementary Data

Injudicious application of nitrogenous fertilizers leads to soil quality deterioration which results into yield loss. The application of biofertilizer containing native efficient rhizobia enhances the nodular properties, N-fixation and soil quality. Therefore, fifty strains of Rhizobium were isolated from root nodule of Raikia french bean and among them only two isolates viz., RBHR-15 and RBHR-21 were confirmed as Rhizobium. The isolates were unable to grow under anaerobic conditions and failed to produce ketolactase enzyme, showed a negative response for gelatin liquefaction and Simmon’s citrate agar test, responded positively towards the indole test, MR-VP, TSI test and could produce NH4+ from peptone in the growth medium. The isolate RBHR-15, could reduce H2S and nitrate whereas, RBHR-21 could not. The growth of both isolates was luxuriant in the nutrient broth containing 1% NaCl and decreased with an increase in the concentration of NaCl and grew profusely in the pH range of 6-8. The generation time of RBHR-15 and RBHR-21 were 16.4and 10.6 h, respectively. The 16s rRNA of both isolates was sequenced and submitted to the National Center for Biotechnology Information (NCBI). The isolates RBHR-15, and RBHR-21 were assigned accession numbers MN480514 and MN480516.

Isolation and characterization of native Rhizobium from root nodules of raikia french bean growing area of Odisha

Injudicious application of nitrogenous fertilizers leads to soil quality deterioration which results into yield loss. The application of biofertilizer containing native efficient rhizobia enhances the nodular properties, N-fixation and soil quality. Therefore, fifty strains of Rhizobium were isolated from root nodule of Raikia french bean and among them only two isolates viz., RBHR-15 and RBHR-21 were confirmed as Rhizobium. The isolates were unable to grow under anaerobic conditions and failed to produce ketolactase enzyme, showed a negative response for gelatin liquefaction and Simmon’s citrate agar test, responded positively towards the indole test, MR-VP, TSI test and could produce NH4+ from peptone in the growth medium. The isolate RBHR-15, could reduce H2S and nitrate whereas, RBHR-21 could not. The growth of both isolates was luxuriant in the nutrient broth containing 1% NaCl and decreased with an increase in the concentration of NaCl and grew profusely in the pH range of 6-8. The generation time of RBHR-15 and RBHR-21 were 16.4and 10.6 h, respectively. The 16s rRNA of both isolates was sequenced and submitted to the National Center for Biotechnology Information (NCBI). The isolates RBHR-15, and RBHR-21 were assigned accession numbers MN480514 and MN480516.

Ectopic expression of the AmDREB1F gene from Ammopiptanthus mongolicus enhances stress tolerance of transgenic Arabidopsis / 生物工程学报

Dehydration-responsive element binding proteins (DREBs) are an important class of transcription factors related to plant stress tolerance. Ammopiptanthus mongolicus is an evergreen broadleaf shrub endemic to desert areas of northwest China, and it has a very high tolerance to harsh environments. In order to reveal the functions and mechanisms of the AmDREB1F gene from this species in enduring abiotic stresses, we performed subcellular localization test, expression pattern analysis, and stress tolerance evaluation of transgenic Arabidopsis harboring this gene. The protein encoded by AmDREB1F was localized in the nucleus. In laboratory-cultured A. mongolicus seedlings, the expression of AmDREB1F was induced significantly by cold and drought but very slightly by salt and heat stresses, and undetectable upon ABA treatment. In leaves of naturally growing shrubs in the wild, the expression levels of the AmDREB1F gene were much higher during the late autumn, winter and early spring than in other seasons. Moreover, the expression was abundant in roots and immature pods rather than other organs of the shrubs. Constitutive expression of AmDREB1F in Arabidopsis induced the expression of several DREB-regulated stress-responsive genes and improved the tolerance of transgenic lines to drought, high salinity and low temperature as well as oxidative stress. The constitutive expression also caused growth retardation of the transgenics, which could be eliminated by the application of gibberellin 3. Stress-inducible expression of AmDREB1F also enhanced the tolerance of transgenic Arabidopsis to all of the four stresses mentioned above, without affecting its growth and development. These results suggest that AmDREB1F gene may play positive regulatory roles in response to abiotic stresses through the ABA-independent signaling pathways.

Orphan crops for future food security

Climate change, along with current agricultural practices, is going to pose a significant challenge for futurefood security, especially in developing countries. Orphan crops can help mitigate this threat due to theirinherent properties of stress tolerance and nutrition content. Industrialization of agriculture has left these minorcrops behind in terms of domestication. As a result, the potential of these crops is underutilized. These cropscan be a game-changer in the long term if necessary steps are taken to improve the quality as well as quantity ofyield. Concerted efforts by many groups around the world have been taken for research and development ofthese crops. Besides, the unique properties of these crops have caught the media attention, which hails thesecrops as superfoods. Favourable government policies to promote these crops can help in the large-scaleadoption of these crops by the farming community. Besides, the stress-resilience of these crops can help boostthe sustainability of agriculture and ensure food security for future generations.

RNA silencing technology: A boon for crop improvement

RNA interference (RNAi) is a powerful tool for gene silencing in different organisms, including plants. It isbeing used in functional genomics to decipher the function of genes. This technology has also witnessed avariety of potential applications in agriculture for crop improvement, including the development of crops forresistance against biotic (weeds, pathogens, insect pests and nematode parasites) and abiotic stresses (drought,high and low temperature, etc.), nutritional quality improvement, healthier oils, delayed ripening, male sterility,modification of flowering time and flower colour, alteration of plant architecture, enhancement of secondaryproducts, and removal of allergens and toxins. RNAi has several advantages over traditional transgenicapproaches as genetically modified RNAi plants do not contain transgene protein, however the risk assessmentof these plants should be examined to rule out any off-target effects.

Advancements in molecular marker technologies and their applications in diversity studies

Crop improvement is a continuous effort, since some 10,000 years ago when primitive man made the transitionfrom hunting and foraging to domestication and crop cultivation. Since then, man-made interventions havechanged the entire scenario of crop evolution, by means of genetic alterations of plants and animals made tosatisfy man’s needs. The process of domestication has led to dramatic changes in their appearance, quality andproductivity that have contributed substantially to global food security. The tremendous decline in cultivableland, freshwater, and increasing risk of biotic and abiotic stress demand immediate attention on cropimprovement to cope with the higher demand of *40% of the food by 2020. Therefore, plant genetic variationplays a key role in plant breeding for its improvement. Most of the genetic variations useful for cropimprovement have been deposited and maintained in seed gene banks across the world; they need to be broughtinto the mainstream of breeding lines. Recent advances and progress made in molecular markers have beensubstantial tools for deeper insights of genetics, and greatly complemented breeding strategies. Integration of thenext-generation sequencing (NGS) technologies with precise phenotyping, association mapping, proteome andmetabolome studies has increased the chances of finding candidate genes and their allelic variants controlling atrait of interest. Further, these functional markers (FMMs), genotype-by-sequencing and association mappingmethodologies have opened new avenues for identification of novel genetic resources (lines) that can facilitateaccelerated crop breeding programs for increased yield, high nutritional quality, and tolerance to a variety ofabiotic and biotic stresses. The details of popular molecular markers, advancement in the technologies andstrategies for crop diversity studies and their application in crop breeding programs are presented here.

Adaptive evolution and selection of stress-resistant Saccharomyces cerevisiae for very high-gravity bioethanol fermentation

Background: In industrial yeasts, selection and breeding for resistance to multiple stresses is a focus of current research. The objective of this study was to investigate the tolerance to multiple stresses of Saccharomyces cerevisiae obtained through an adaptive laboratory evolution strategy involving a repeated liquid nitrogen freeze­thaw process coupled with multi-stress shock selection. We also assessed the related resistance mechanisms and very high-gravity (VHG) bioethanol production of this strain. Results: Elite S. cerevisiae strain YF10-5, exhibiting improved VHG fermentation capacity and stress resistance to osmotic pressure and ethanol, was isolated following ten consecutive rounds of liquid nitrogen freeze­thaw treatment followed by plate screening under osmotic and ethanol stress. The ethanol yield of YF10-5 was 16% higher than that of the parent strain during 35% (w/v) glucose fermentation. Furthermore, there was upregulation of three genes (HSP26, HSP30, and HSP104) encoding heat-shock proteins involved in the stress response, one gene (TPS1) involved in the synthesis of trehalose, and three genes (ADH1, HXK1, and PFK1) involved in ethanol metabolism and intracellular trehalose accumulation in YF10-5 yeast cells, indicating increased stress tolerance and fermentative capacity. YF10-5 also showed excellent fermentation performance during the simultaneous saccharification and fermentation of VHG sweet potato mash, producing 13.40% (w/ v) ethanol, which corresponded to 93.95% of the theoretical ethanol yield. Conclusions: A multiple-stress-tolerant yeast clone was obtained using adaptive evolution by a freeze­thaw method coupled with stress shock selection. The selected robust yeast strain exhibits potential for bioethanol production through VHG fermentation.

Towards an Understanding of Physiological and Biochemical Mechanisms of Drought Tolerance in Plant

Drought stress is one of the major abiotic stress that can causes huge loss to the world food production. It remains a major contributor to severe food shortage and famine. With a consistent increase in world population, pressure will continue to mount on the existing yet limited water resources. The situation is respected to further aggravate due to the predicted increase in temperature and decrease in precipitation consequent upon global warming. Water scarcity has already become a severe constraint in plant survival and productivity of crops in arid and semi-arid regions. The active response of plants to drought stress through various biochemical and physiological modifications improves the metabolism and can further the mobilize various defense mechanisms in order to enhance survival of the plants under conditions of drought. In this review, various physiological and biochemical responses in plants towards enhancement of drought tolerance are discussed.

Longevity and Stress Resistant Property of 6-Gingerol from Zingiber officinale Roscoe in Caenorhabditis elegans

In order to discover lifespan-extending compounds made from natural resources, activity-guided fractionation of Zingiber officinale Roscoe (Zingiberaceae) ethanol extract was performed using the Caenorhabditis elegans (C. elegans) model system. The compound 6-gingerol was isolated from the most active ethyl acetate soluble fraction, and showed potent longevity-promoting activity. It also elevated the survival rate of worms against stressful environment including thermal, osmotic, and oxidative conditions. Additionally, 6-gingerol elevated the antioxidant enzyme activities of C. elegans, and showed a dose-depend reduction of intracellular reactive oxygen species (ROS) accumulation in worms. Further studies demonstrated that the increased stress tolerance of 6-gingerol-mediated worms could result from the promotion of stress resistance proteins such as heat shock protein (HSP-16.2) and superoxide dismutase (SOD-3). The lipofuscin levels in 6-gingerol treated intestinal worms were decreased in comparison to the control group. No significant 6-gingerol-related changes, including growth, food intake, reproduction, and movement were noted. These results suggest that 6-gingerol exerted longevity-promoting activities independently of these factors and could extend the human lifespan.

Regulation mechanism of rnc gene on Streptococcus mutans environmental tolerance and its mechanism / 口腔疾病防治

Objective @#To study the changes of acid resistance, oxidation resistance and high osmotic pressure resistance of Streptococcus mutans after knockout of rnc gene and its possible regulatory mechanism.@*Methods@#Through PCR ligation mutagenesis, an rnc knockout mutant (Smurnc) was constructed. Acid tolerance, oxidation tolerance and high osmotic pressure tolerance were compared between Smurnc and the wild strain respectively. Real-time RT-PCR was used to verify the changes in expression of stress tolerance related genes at the transcriptional level.@*Results @#When rnc gene was knocked out, the acid tolerance (χ2=13.464, P=0.001) and oxidation tolerance (χ2=4.505, P=0.048) of Streptococcus mutans was significantly decreased, but the high osmotic pressure tolerance was significantly increased (χ2=11.971, P=0.001). Expression of stress tolerance related genes luxS and ropA (0.64 and 0.51 times expression of the wild strain) had been significantly downregulated (P<0.001). Expression of htrA and brpA (1.56 and 1.80 times expression of the wild strain) had been significantly upregulated (P<0.001).@*Conclusion @#The deletion of rnc gene affects the expression of the environmental tolerance related genes of Streptococcus mutans, which reduces its acid resistance and oxidation resistance, and enhances its tolerance to hypertonic pressure.

Assessment of watermelon accessions for salt tolerance using stress tolerance indices / Avaliação de acessos de melancia para tolerância ao sal utilizando índices de tolerância ao estresse

ABSTRACT Salt stress is the most significant constraint for agricultural production in arid and semi-arid regions. Thus, genetically improved stress-tolerant varieties are needed for the future. The identification of salt-tolerant genotypes is the starting point for such breeding studies. This study was conducted to determine and assess the tolerance of different watermelon genotypes under saline conditions. Twenty-two watermelon genotypes and accessions were grown in pots with 3 kg of soil in four saline stress conditions (0 mmol kg-1 as the control, 25, 50 and 100 mmol kg-1 NaCl). The detrimental effects of salt stress on the plants were evident with increasing doses of NaCl. Stress indices calculated over the plant dry weights under the 100 mmol kg-1 salinity level were used to assess the salt tolerance of the genotypes. Stress intensity was calculated as 0.76. Such a value indicated that the highest dose of salt exerted severe stress on the plants. The G04, G14 and G21 genotypes were considered to be salt tolerant, since these genotypes showed the highest values of K/Na and Ca/Na ratios in the plant tissue. The losses in dry mass at severe salt stress reached 75.48%. In principal component analyses, the genotypes had positive correlations with stress tolerance indices of MP (mean productivity), GMP (geometric mean productivity) and STI (stress tolerance index). The GMP and STI indices indicated that G04 (a member of Citrullus colocynthis), G14 and G21 could be prominent sources to develop salt tolerance.

RESUMO O estresse salino é a restrição mais importante para a produção agrícola em regiões áridas e semi-áridas. Portanto, há necessidade de plantas geneticamente tolerantes ao estresse salino no futuro. Identificação de genótipos tolerantes ao sal é o ponto de partida de estudos de melhoramento. O presente estudo foi conduzido para determinar e avaliar a tolerância de diferentes genótipos de melancia sob condições salinas. Um total de 22 genótipos e acessos de melancia foram cultivados em vasos de 3 kg de solo com quatro condições de estresse salino diferentes (0 mmol kg-1 como controle, 25, 50 e 100 mmol kg-1 de NaCl). Dependendo do aumento da dose de NaCl, os efeitos prejudiciais do estresse salino nas plantas também aumentaram. Os índices de estresse calculados sobre os pesos secos das plantas com um nível de salinidade de 100 mmol kg-1 foram utilizados para avaliar a tolerância ao sal dos genótipos. A intensidade de tensão foi calculada como 0.76. Indicando que a maior dose de sal exerce um estresse salino grave nas plantas. Os genótipos G04, G14 e G21 foram considerados tolerantes, uma vez que apresentaram os maiores valores nas relações K/Na e Ca/Na. As perdas em pesos secos com estresse salino grave atingiram 75.48%. Na análise de componentes principais, os genótipos tiveram correlações positivas com os índices de tolerância ao estresse de PM (produtividade média), GMP (produtividade média geométrica) e STI (índice de tolerância ao estresse).Os índices GMP e STI indicaram G04 (um membro de C. colocynthis), G14 e G21 como materiais proeminentes para a tolerância ao sal.

Dark septate endophyte decreases stress on rice plants

Abstract Abiotic stress is one of the major limiting factors for plant development and productivity, which makes it important to identify microorganisms capable of increasing plant tolerance to stress. Dark septate endophytes can be symbionts of plants. In the present study, we evaluated the ability of dark septate endophytes isolates to reduce the effects of water stress in the rice varieties Nipponbare and Piauí. The experiments were performed under gnotobiotic conditions, and the water stress was induced with PEG. Four dark septate endophytes were isolated from the roots of wild rice (Oryza glumaepatula) collected from the Brazilian Amazon. Plant height as well as shoot and root fresh and dry matter were measured. Leaf protein concentrations and antioxidant enzyme activity were also estimated. The dark septate endophytes were grown in vitro in Petri dishes containing culture medium; they exhibited different levels of tolerance to salinity and water stress. The two rice varieties tested responded differently to inoculation with dark septate endophytes. Endophytes promoted rice plant growth both in the presence and in the absence of a water deficit. Decreased oxidative stress in plants in response to inoculation was observed in nearly all inoculated treatments, as indicated by the decrease in antioxidant enzyme activity. Dark septate endophytes fungi were shown to increase the tolerance of rice plants to stress caused by water deficiency.

Effect of salinity and use of stress indices of morphological and physiological traits at the seedling stage in rice.

Rice (Oryza sativa L.) is the most important cereal crop and a major staple food for majority of the human populations worldwide. Rice crop is sensitive to salinity. In spite of large number of studies on salinity tolerance of rice, our knowledge on the overall effect of salinity on rice seedling growth is limited. Improvement in salt tolerance of crop plants remains indescribable, largely due to the fact that salinity is a complex trait which affects almost every aspect of the physiology, biochemistry and genomics of plants. The present investigation was conducted to establish the relationship between various morphological, physiological traits and stress indices. A set of 131 rice accessions was evaluated in two levels namely, non-stress (EC ~ 1.2 dS/m) and saline stress (EC ~ 10 dS/m) in hydroponics at seedling stage. Root length and shoot lengths were reduced by 52 and 50%, respectively in saline stress compared to non-stress conditions. There was a significant correlation between various morphological and physiological parameters in non-saline in addition to saline stress as well as non-stress. The effect of the increased Na+ concentration in the medium is detrimental to root length and shoot length as observed by reduction in root length and a concomitant reduction in shoot length. Increased concentration of Na+ led to augmented Na+/K+ ratio with increased stress in the medium and decreased expression of traits. A significant positive correlation (r=0.60) was noticed between stress tolerance index (STI) of root and shoot length. The stress susceptibility index (SSI) for root length was expressed significant positive correlation with SSI for shoot length (r=0.43). SSI for K+ content was registered significant negative correlation with STI for Na+ content (r=-0.43). The three accessions namely, IC 545004, IC 545486 and IC 545215 were found to be the best performers adjudged on the morphological and physiological criteria in saline stress situation. These three rice accessions could be used as a donor parent or for genotypic studies in future breeding programs.

Modulación del estado de óxido-reducción por peróxido de hidrógeno en la etapa de maduración ovocitaria: efecto sobre el desarrollo embrionario en bovinos / Modulation of redox state by hydrogen peroxide in the stage of oocyte maturation: effect on embryonic development in cattle

El estrés oxidativo es definido como un desbalance entre la producción de oxidantes y antioxidantes. La inducción de tolerancia a estrés en los ovocitos conllevaría a un mejor desarrollo embrionario. En bovinos, la incubación de ovocitos maduros con diferentes estresores (térmicos, alta presión hidrostática, oxidativos) incrementaría la tasa de generación de blastocitos. Este estudio evalúa el efecto de la modulación del estado redox incrementando el estrés oxidativo con H2O2 en ovocitos maduros bajo condiciones de cultivo in vitro y su efecto sobre el potencial de desarrollo embrionario. Para ello, ovocitos procedentes de ovarios de matadero fueron madurados en medio TCM-199 suplementado durante 22­23 h, a 38,5 °C, 5 % CO2 y humedad a saturación. Al final de las 22­23 h se incubaron los ovocitos maduros con 0, 50, 100 y 200 µM H2O2. La fecundación in vitro se realizó co-incubando los ovocitos durante 18 h con una concentración final de 1x106 espermatozoides/mL. Los presuntos cigotos fueron denudados y cultivados en medio KSOM-0,4 % BSA a 38,5 °C en atmósfera de baja tensión de O2 (5 % O2, 5 % CO2 y 90 % N2) y humedad a saturación. El estrés oxidativo inducido con H2O2 a una concentración de 50 y 100 µM produce una tasa de división de los embriones similar al control (88,7 %, 83,2 % y 86,4 % respectivamente, p>0,05), disminuyendo significativamente al utilizar una concentración de 200 µM (58,8 %, p<0,05). Asimismo, H2O2 causó un efecto similar en la tasa de blastocitos con 50 µM (20,4 % vs. 25,8 % control, p>0.05) pero disminuyó significativamente con 100 y 200 µM (10,7 % y 3,3 % respectivamente, p<0,05). Es posible, que estos embriones resistentes al estrés oxidativo puedan tener una mayor sobrevida durante los procesos de criopreservación que generan altos niveles de especies reactivas de oxígeno en los embriones.

Oxidative stress is defined as an imbalance between the production of oxidants and antioxidants. The induction of stress tolerance in oocytes leads to a better embryonic development. In cattle incubating mature oocytes with different stressors (thermal, high hydrostatic pressure, oxidative) increase the generation rate of blastocysts. The purpose of this study was to evaluate the effect of modulating the redox state increasing the oxidative stress through H2O2 in mature oocyte under in vitro culture conditions and its effect on the potential of embryonic development. To do this, oocytes from slaughterhouse ovaries were matured in TCM-199 medium supplemented for 22­23 h at 38.5 °C, 5 % CO2 and humidified atmosphere. At the end of 22­23 h, the treatments with 0, 50, 100 and 200 µM H2O2 were applied for 1 h. IVF was performed co-incubating the eggs for 18 h with a final concentration of 1x106 sperm/mL. The presumptive zygotes were denuded and cultured in medium KSOM-0.4 % BSA to 38.5 °C in an atmosphere of low concentration of O2 (5 % O2, 5 % CO2 and 90 % N2) and humidified atmosphere. The results show that the induction of oxidative stress by H2O2 produces a similar effect using a concentration of 50 and 100 mM in the cleavage rate of embryos compared to control (88.7 %, 83.2 % and 86,4 % respectively, p>0.05) and decreasing significantly by using a concentration of 200 mM (58.8 %, p<0.05). Also, H2O2 caused a similar effect on the rate of blastocysts with 50 µM (20.4 % vs. 25.8 control, p>0.05) but decreased significantly with 100 and 200 µM (10.7 % and 3.3 % respectively, p<0.05). It is possible that these embryos resistant to oxidative stress may have a higher survival in the cryopreservation processes that generating high levels of reactive oxygen species.

Anti-aging properties of Ribes fasciculatum in Caenorhabditis elegans / 中国天然药物

The present study investigated the effects and underlying mechanism of ethylacetate fraction of Ribes fasciculatum (ERF) on the lifespan and stress tolerance using a Caenorhabditis elegans model. The longevity activity of ERF was determined by lifespan assay under normal culture condition. The survival rate of nematodes under various stress conditions was assessed to validate the effects of ERF on the stress tolerance. To determine the antioxidant potential of ERF, the superoxide dismutase (SOD) activities and intracellular reactive oxygen species (ROS) levels were investigated. The ERF-mediated change in SOD-3 expression was examined using GFP-expressing transgenic strain. The effects of ERF on the aging-related factors were investigated by reproduction assay and pharyngeal pumping assay. The intestinal lipofuscin levels of aged nematodes were also measured. The mechanistic studies were performed using selected mutant strains. Our results indicated that ERF showed potent lifespan extension effects on the wild-type nematode under both normal and various stress conditions. The ERF treatment also enhanced the activity and expression of superoxide dismutase (SOD) and attenuated the intracellular ROS levels. Moreover, ERF-fed nematodes showed decreased lipofuscin accumulation, indicating ERF might affect age-associated changes in C. elegans. The results of mechanistic studies indicated that there was no significant lifespan extension in ERF-treated daf-2, age-1, sir-2.1, and daf-16 null mutants, suggesting that they were involved in ERF-mediated lifespan regulation. In conclusion, R. fasciculatum confers increased longevity and stress resistance in C. elegans via SIR-2.1-mediated DAF-16 activation, dependent on the insulin/IGF signaling pathway.

Moringa oleifera Prolongs Lifespan via DAF-16/FOXO Transcriptional Factor in Caenorhabditis elegans

Here in this study, we investigated the lifespan-extending effect and underlying mechanism of methanolic extract of Moringa olelifa leaves (MML) using Caenorhabditis elegans (C. elegans) model system. To define the longevity properties of MML we conducted lifespan assay and MML showed significant increase in lifespan under normal culture condition. In addition, MML elevated stress tolerance of C. elegans to endure against thermal, oxidative and osmotic stress conditions. Our data also revealed that increased activities of antioxidant enzymes and expressions of stress resistance proteins were attributed to MML-mediated enhanced stress resistance. We further investigated the involvement of MML on the aging-related factors such as growth, food intake, fertility, and motility. Interestingly, MML significantly reduced growth and egg-laying, suggesting these factors were closely linked with MML-mediated longevity. We also observed the movement of aged worms to estimate the effects of MML on the health span. Herein, MML efficiently elevated motility of aged worms, indicating MML may affect health span as well as lifespan. Our genetic analysis using knockout mutants showed that lifespan-extension activity of MML was interconnected with several genes such as skn-1, sir-2.1, daf-2, age-1 and daf-16. Based on these results, we could conclude that MML prolongs the lifespan of worms via activation of SKN-1 and SIR-2.1 and inhibition of insulin/IGF pathway, followed by DAF-16 activation.

Novel Molecular Basis for Vascular Health Regulated by Vasohibin-1

The endothelium covers the entire luminal surface of blood vessels, organizes the interface between the blood and underlying tissues, and controls vascular tone, blood clotting, transport of various substances across the vascular wall, adhesion and transmigration of leukocytes, and so forth. The structural and functional integrity of endothelium is essential for the maintenance of vascular health. In light of its important role, the endothelium should have a self-defense system such as vasohibin-1 (VASH1), a protein preferentially expressed in endothelial cells (ECs). Unique features of VASH1 are its anti-angiogenic activity and ability to promote stress tolerance of ECs. This mini review summarizes the current understanding of VASH1, especially the posttranscriptional regulation of its synthesis in response to cellular stresses and aging.

Seedling survival of Handroanthus impetiginosus (Mart ex DC) Mattos in a semi-arid environment through modified germination speed and post-germination desiccation tolerance / Sobrevivência de plântulas de Handroanthus impetiginosus (Mart ex DC) Mattos em ambiente semi-árido ocorre por modificação da velocidade de germinação e da tolerância à dessecação pós germinação

Abstract Uniform rapid seed germination generally forms a great risk for the plant population if subsequent intermittent precipitation causes desiccation and seedling death. Handroanthus impetiginosus can be found commonly in a wide range of biomes within Brazil including those that are semi-arid. Germination and early growth was studied to understand how germinated seeds survive under these stringent conditions. Accessions were sampled from four seasonally dry biomes in Brazil. Precipitation at the start of the rainy season in the Caatinga, a semi-arid biome, is less predictable and the number of successive dry days per dry interval in the first four months of the rainy season was higher than in the other studied biomes. Plants from the Caatinga produced thicker seeds and this trait concurred with slow germination and stronger osmotic inhibition of germination across the accessions, forming a stress avoidance mechanism in the Caatinga. Post-germination desiccation tolerance was high in the Caatinga accession, could be re-induced in accessions from biomes with more regular precipitation (Cerrado and transition zone), but remained poor in the Cerradão accession; thus forming a stress tolerance mechanism. Production of adventitious roots ascertained survival of all tested individuals from all four locations, even if protruded radicles did not survive desiccation, forming an additional stress tolerance mechanism. A sequence of stress avoidance and stress tolerance mechanisms in seeds and germinated seeds was associated with precipitation patterns in different biomes. These mechanisms purportedly allow rapid seedling establishment when conditions are suitable and enable survival of the young seedling when conditions are adverse.

Resumo A germinação rápida e uniforme geralmente pode apresentar riscos para a população de plantas caso a precipitação ocorra de maneira intermitente, provocando seca e morte das plântulas. Handroanthus impetiginosus pode ser encontrado em uma grande variedade de biomas no Brasil. A germinação e o crescimento inicial das plântulas de Handroanthus impetiginosus foram estudadas para compreender como as sementes germinadas sobrevivem nestas condições. Acessos de quatro biomas que apresentam secas sazonais foram amostrados. A precipitação, no início da estação chuvosa na Caatinga, um bioma semi-árido, é menos previsível e o número de dias secos consecutivos por intervalo de seca, nos primeiros quatro meses da estação chuvosa, foi maior do que nos outros biomas estudados. Plantas do bioma Caatinga produzem sementes mais espessas e essa característica está associada com uma germinação lenta e com a inibição osmótica maior da germinação através dos acessos, formando um mecanismo para evitar o estresse. Tolerância à dessecação em sementes germinadas foi superior no bioma Caatinga e que podem ser reinduzida em acesso com uma precipitação mais regular (Cerrado e na zona de transição), mas manteve-se baixa no acesso Cerradão, formando assim um mecanismo para evitar o estresse. Produção de raízes adventícias foi observada nos indivíduos estudados de todos os quatro biomas, mesmo quando as raízes primárias não sobreviveram à dessecação, formando um mecanismo adicional de tolerância ao estresse. Assim, foi observado estratégias para evitar o estresse e mecanismos de tolerância ao estresse em sementes e sementes germinadas associada com padrões de precipitação nos diferentes biomas estudados. Estes mecanismos podem favorecer o estabelecimento das plântulas de forma rápida quando as condições são adequadas e permitirem a sobrevivência de plântulas quando as condições são adversas.

Lifespan Extending and Stress Resistant Properties of Vitexin from Vigna angularis in Caenorhabditis elegans

Several theories emphasize that aging is closely related to oxidative stress and disease. The formation of excess ROS can lead to DNA damage and the acceleration of aging. Vigna angularis is one of the important medicinal plants in Korea. We isolated vitexin from V. angularis and elucidated the lifespan-extending effect of vitexin using the Caenorhabditis elegans model system. Vitexin showed potent lifespan extensive activity and it elevated the survival rates of nematodes against the stressful environments including heat and oxidative conditions. In addition, our results showed that vitexin was able to elevate antioxidant enzyme activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner. These studies demonstrated that the increased stress tolerance of vitexin-mediated nematode could be attributed to increased expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). In this work, we also studied whether vitexin-mediated longevity activity was associated with aging-related factors such as progeny, food intake, growth and movement. The data revealed that these factors were not affected by vitexin treatment except movement. Vitexin treatment improved the body movement of aged nematode, suggesting vitexin affects healthspan as well as lifespan of nematode. These results suggest that vitexin might be a probable candidate which could extend the human lifespan.