Causes of problems concerning skin-set on table potatoes

Idag ställs stora krav på matpotatisen utseende. Att förbättra skalfinishen är många gånger önskvärt för matpotatisodlaren. En försämring av skalfastheten hos etablerade matpotatissorter har uppmärksammats av Lars Bolin, VD på Svensk Potatis. Genom att undersöka praktisk odling och därigenom samla in underlag för slutsatser alternativt för framtida studier inom området är förhoppningen att minska problem med skalhållfasthet. Målsättningen är att hitta metoder som ger potatisen ett bra hållfast skal vilket skulle öka lönsamheten för odlarna. Skalet består av tre olika lager av celler: phellem, phellogen och phelloderm. Flossning inträffar när phellogencellagret går sönder och på så vis inte kan hålla ihop phellem och phellogen längre. Det ursprungliga skalet är färdigbildat strax efter knölsättning när knölarna har samma storlek som en ärta. För att skydda knölen mot patogener och uttorkning i lager är det viktigt att skalet behålls intakt. Skalets bildning och mognad är ett komplext samspel mellan många olika processer vars fullständiga funktion inte är fullt utredd. Blastdödning är en åtgärd som genomförs för att påskynda mognaden av knölarnas skal. Dess effektivitet beror på genotyp där tidiga sorter är lättare att blastdöda jämfört med sena. Skalbildningsutveckling hos rödskaliga sorter är oftast långsammare och mer problematisk jämfört med gulskaliga sorter. Alltför höga kvävegivor förlänger tillväxtsäsongen och signalen för initiering av avmognad senareläggs. Detta innebär att skalet inte hinner fullbildas innan lagringen. Varsam kvävegödsling i kombination med en strävan efter jämn tillväxt där näringsstatusen i plantan kontrolleras under säsongen är konkreta råd från potatisrådgivningen. Försök i både Finland och USA visar på positiva resultat av kalci-umgödsling i potatis. Potatisplantan behöver kalcium för att bygga upp bra cell-membran och starka cellväggar samtidigt som kalcium är ett viktigt växthormon. Då knölar är lågtranspirerande organ har de ofta kalciumbrist eftersom vattengradienten är mycket högre för vattentransporten från blad till luft jämfört med vattentransporten från knöl ut till fuktig jord. För att kunna mäta och jämföra skalfasthet behövs en metod som är objektiv och reproducerbar. En idag accepterad metod är mätning med hjälp av torquemeter. Matpotatisodlare och potatisrådgivare med geografisk spridning har intervjuats för att delge sina erfarenheter och åtgärder för att förbättra skalfastheten. Bland dessa finns odlare och rådgivare som gödslar respektive förespråkar kalciumgödsling. I intervjuerna ställdes frågor om odlarnas strategier för att uppnå bra skalfasthet, blastdödningstekniker, gödslingsstrategier, upptagningsförhållande, lagring m.m.Today the requirements on the visual appearance of table potatoes are set high. Improvement of the surface of the potato is often desirable to the grower of table potatoes. A deterioration of skin-set in frequently grown varieties of table potatoes has been seen by Lars Bolin, CEO at Svensk Potatis. By examining the practical potato farming and collect material for conclusions alternatively for future studies in the area, hope is to reduce the problems concerning bad skin-set. The goal is to find methods that give the potatoes a good strong skin which would increase profit-ability for the growers. The skin consists of three different layers of cells: phellem, phello-gen and phelloderm. The native skin is completely formed shortly after the nascent tuber has reached the size of a pea. To protect the tuber against pathogens and dehydration it is crucial that the skin is kept intact. The formation and maturity of the skin is a complex interaction between numerous processes’ whose complete function is not determined. Haulm desiccation is a measure used to enhance the maturity of the skin of the tubers. The efficiency of this measure is partly dependent on the genotype with early maturing varieties are easier to haulm desiccate than late maturing varieties. Skin-set development in red skinned varieties is often slower and more problematic than in yellow skinned varieties. Excessive use of nitrogen fertilizers extends the growing period and the signal of initiation of maturity is delayed. This means that the skin does not have time to fully form before the tuber is being put into storage. Careful use of nitrogen fertilizers in combination with an ambition of continuous growth with regular measurements of the nutritional status of the plant during the growth season are concrete advice given by potato crop advisers. Field trials in both Finland and the U.S show positive results in cal-cium fertilization in potato crop. The potato plant needs calcium for the formation of good cell membranes and strong cell walls while calcium also being a plant hor-mone. Given that tubers are low transpiring organs calcium deficiency is common since the water gradient is much higher for water transport from leaf to air com-pared to water transport from tuber to moist soil. In order to measure and compare skin-set there is a need for a method that is objective and reproducible. An accepted method is measurement by use of a torquemeter. Table potato growers and potato crop advisers geographically scat-tered have been interviewed in order to share their experience and measures taken to enhance skin-set. Among these there are growers and crop advisers who use and recommend calcium fertilization. In the interviews the growers were asked about their strategies for achieving a good skin-set concerning haulm desiccation strategy, fertilization plan, harvesting conditions, storage and so on

Reducerade fungiciddoser vid bekämpning av potatismögel - vilka blir följderna?

Potato late blight, caused by the oomycete Phytophthora infestans, is the most devastating crop disease in potato crop globally and annually cost growers 5 billion USD in losses and control measures. Large quantities of fungicides are used for the control of potato late blight in order to avoid yield loss and to limit the risk of tuber blight. New fungicides have a better ability to achieve a good level of control at lower doses compared to older fungi- cides. A field trial was conducted to investigate if it is possible to lower the dose while maintaining both yield level and a good protection against tuber blight. In the trial, the control of potato late blight using full recommended dose of fungicide was compared to half recommended dose. Generally crop protection salesmen and farmers advice against using half the recommended fungicide dose for the control of potato late blight. It is al- leged that this practice results in a selection of phenotypes of P. infestans which are more aggressive and have a higher fungicide tolerance. To examine if these claims are valid, isolates of P. infestans were collected from plots treated with full dose of fungicide (K2), half dos fungicide (K1) and untreated plots (K0). The collected isolates were tested for aggressiveness by measuring latency period, lesion growth and spore production. In addi- tion, test for mycelial growth on agar amended with three levels fungicide were performed. Tests were carried out with all three fungicide used in the field trial; Infinito, Ranman Top and Revus Top. Microsatellites were used as markers to detect genotypic differentiation between the three sets of samples. Results from the aggressiveness tests showed that no significant differences in aggres- siveness could be found between the isolates from K2 and the isolates from K1. Only iso- lates from K0 were significantly less aggressive. The mycelial growth on fungicide amended agar was significantly higher for isolates from K2 in all tests except one dose level, in one fungicide. The differences in mycelia growth among isolates from K0 and K1 varied. The infection of P. infestans in the field trial was low and no differences in yield or occurrence of tuber blight were found. No genotypic differentiation was detected despite the significant differences in aggressiveness between samples collected from the different treatments. This indicates that the observed differences in phenotype are due to changes in the gene expression rather than in the population structure. Collectively the results show that usage of half the recommended dose of fungicide did not increase aggressiveness, reduce yield, increase fungicide tolerance or occurrence of tuber blight in the field trial. Full dose however increased phenotypic fungicide tolerance.Globalt sett är potatisbladmögel den mest förödande sjukdomen inom potatisodling och medför årligen kostnader på omkring 5 miljarder US dollar i utebliven produktion och kontrollåtgärder. Bladmögel orsakas av oomyceten Phytophthora infestans. Stora mängder fungicider används för att bekämpa potatisbladmögel för att undvika skördebortfall och minska risken för brunröta. Till skillnad från äldre preparat, uppnår moderna bladmögel- fungicider redan vid låga doser en bekämpningseffekt som är jämförbar med den vid full rekommenderad dos. För att belysa möjligheten att minska dosen samtidigt som samma skördenivå och låga förekomst av brunröta bibehålls genomförde Lyckeby Starch ett fält- försök 2015. I fältförsöket bekämpades bladmögel med full respektive halv rekommende- rad fungiciddos. Växtskyddsförsäljare avråder ofta från bekämpning med reducerade fung- iciddoser. Detta för att reducerade doser påstås selektera fram aggressivare och mer fungi- cidtolerant bladmögel. För att undersöka om dessa påståenden stämmer samlades isolat av P. infestans in från parceller behandlade med full dos (K2), halv dos (K1) och parceller som var obehandlade (K0). De insamlade isolaten undersöktes på laboratorium för aggres- sivitet genom att mäta latenstid, lesionstillväxt och sporproduktion. Dessutom mättes isola- tens myceltillväxt på agar där tre olika nivåer av fungicid hade tillsatts. Alla tre fungici- derna som ingick i bekämpningsprogrammet i fältförsöket; Infinito, Ranman Top och Re- vus Top, undersöktes. Genotyp bestämdes med mikrosatelliter för att utreda om popula- tionsstrukturen skiljde mellan de olika leden. Aggressivitetstesterna visade att det inte fanns några skillnader i aggressivitet mellan isolat från K2 respektive K1. Endast isolat från K0 hade signifikant lägre aggressivitet. Myceltillväxten på agar där fungicid hade tillsatts var signifikant högre för K2 i alla led förutom en dosnivå för ett preparat. Skillnaderna i tillväxt mellan K1 och K0 varierade. I fältförsöket var skillnaderna i bladmögelangrepp små och inga skillnader i skörd eller i förekomst av brunröta uppmättes. Ingen genetisk populationsdifferentiering detekterades, trots signifikanta skillnader i aggressivitet mellan isolaten som samlats in från de olika behandlingarna. Detta tyder på att skillnaderna i fenotyp beror på en förändring i genut- trycket snarare än förändring i populationsstruktur. Sammantaget visar resultaten att halverade doser, inte ger aggressivare bladmögel, lägre skörd, högre fungicidtolerans och större förekomst av brunröta i fältförsöket. Däremot selekterade full dos fram fenotyper med högre fungicidtolerans

Quantitative genetics of breeding coloration in sand lizards; genic capture unlikely to maintain additive genetic variance

Sexual selection on fitness-determining traits should theoretically erode genetic variance and lead to low heritability. However, many sexually selected traits maintain significant phenotypic and additive genetic variance, with explanations for this “lek paradox” including genic capture due to condition-dependence, and breaks on directional selection due to environmental sources of variance including maternal effects. Here we investigate genetic and environmental sources of variance in the intrasexually selected green badge of the sand lizard (Lacerta agilis). The badge functions as a cue to male fighting ability in this species, and male–male interactions determine mate acquisition. Using animal models on a pedigree including three generations of males measured over an extensive 9-year field study, we partition phenotypic variance in both badge size and body condition into additive genetic, maternal, and permanent environmental effects experienced by an individual over its lifespan. Heritability of badge size was 0.33 with a significant estimate of underlying additive genetic variance. Body condition was strongly environmentally determined in this species and did not show either significant additive genetic variance or heritability. Neither badge size nor body condition was responsive to maternal effects. We propose that the lack of additive genetic variance and heritability of body condition makes it unlikely that genic capture mechanisms maintain additive genetic variance for badge size. That said, genic capture was originally proposed for male traits under female choice, not agonistic selection. If developmental pathways generating variance in body condition, and/or the covarying secondary sex trait, differ between inter- and intrasexual selection, or the rate at which their additive genetic variance or covariance is depleted, future work may show whether genic capture is largely restricted to intersexual selection processes.publishedVersio

Degrees of change: between and within population variation in thermal reaction norms of phenology in a viviparous lizard

As the earth warms, populations will be faced with novel environments to which they may not be adapted. In the short term, populations can be buffered against the negative effects, or maximize the beneficial effects, of such environmental change via phenotypic plasticity and, in the longer term, via adaptive evolution. However, the extent and direction of these population-level responses will be dependent on the degree to which responses vary among the individuals within them (i.e., within population variation in plasticity), which is, itself, likely to vary among populations. Despite this, we have estimates of among-individual variation in plastic responses across multiple populations for only a few systems. This lack of data limits our ability to predict the consequences of environmental change for population and species persistence accurately. Here, we utilized a 16-yr data set from climatically distinct populations of the viviparous skink Niveoscincus ocellatus tracking over 1,200 litters from more than 600 females from each population to examine inter- and intrapopulation variability in the response of parturition date to environmental temperature. We found that these populations share a common population-mean reaction norm but differ in the degree to which reaction norms vary among individuals. These results suggest that even where populations share a common mean-level response, we cannot assume that they will be affected similarly by altered environmental conditions. If we are to assess how changing climates will impact species and populations accurately, we require estimates of how plastic responses vary both among and within populations.publishedVersio

New ‘stimuli-enriched’ laboratory bioassay used to identify improved botanical repellent treatment, Lem-ocimum, to control the stored-grain pest Tribolium castaneum

A laboratory study of Tribolium castaneum, a major pest of stored grain, was conducted to develop a more efficient and effective ‘choice’ bioassay for identification of new repellent botanical treatments. Standard bioassays to test the repellency of candidate plants include pit-fall traps and open arena choice tests, environments lacking in some of the most important natural stimuli that guide the movement of food-searching beetles, e.g., 1) materials they can burrow through, which stimulate ‘positive thigmotaxis’, 2) a range of light and dark areas, which stimulate ‘negative phototaxis’ and 3) three-dimensional habitats, which stimulate ‘positive geotaxis.’ The lack of these stimuli can lead to two common problems; ‘low efficiency’ (high proportion of beetles remain in the area that surrounds treatments without making a ‘choice’), and ‘low efficacy’ (high variability in proportions found in control and treated samples). The new ‘stimuli-enriched’ bioassay, which included all three of the above stimuli, was significantly more efficient (P < 0.0001) and effective than three standard bioassays. The stimuli-enriched bioassay was used to compare the repellency of four candidate plants; Ocimum basilicum (Sweet Basil) and Cymbopogon nardus (Lemongrass) were significantly more repellent than Vernonia amygdalina or Nauclea diderrichii (Tukey Contrasts; P < 0.01). A novel method of applying repellent material (a paste of repellent plant is applied between the layers of double bagged grain) was tested on the most promising repellent plants materials; a combination of C. nardus and O. basilicum (‘Lem-ocimum’) at 0.5% w/w of each was significantly more effective than O. basilicum on its own (Tukey Contrasts; P < 0.05). These results show that the stimuli-enriched bioassay provides more consistent and accurate assessments than the standard bioassays of the repellency of candidate botanicals, and that Lem-ocimum treated double-bags are a promising new method of protecting sorghum from T. castaneum

Association of Genetic Markers with CSF Oligoclonal Bands in Multiple Sclerosis Patients

Objective:to explore the association between genetic markers and Oligoclonal Bands (OCB) in the Cerebro Spinal Fluid (CSF) of Italian Multiple Sclerosis patients.Methods:We genotyped 1115 Italian patients for HLA-DRB1*15 and HLA-A*02. In a subset of 925 patients we tested association with 52 non-HLA SNPs associated with MS susceptibility and we calculated a weighted Genetic Risk Score. Finally, we performed a Genome Wide Association Study (GWAS) with OCB status on a subset of 562 patients. The best associated SNPs of the Italian GWAS were replicated in silico in Scandinavian and Belgian populations, and meta-analyzed.Results:HLA-DRB1*15 is associated with OCB+: p = 0.03, Odds Ratio (OR) = 1.6, 95% Confidence Limits (CL) = 1.1-2.4. None of the 52 non-HLA MS susceptibility loci was associated with OCB, except one SNP (rs2546890) near IL12B gene (OR: 1.45; 1.09-1.92). The weighted Genetic Risk Score mean was significantly (p = 0.0008) higher in OCB+ (7.668) than in OCB- (7.412) patients. After meta-analysis on the three datasets (Italian, Scandinavian and Belgian) for the best associated signals resulted from the Italian GWAS, the strongest signal was a SNP (rs9320598) on chromosome 6q (p = 9.4×10-7) outside the HLA region (65 Mb).Discussion:genetic factors predispose to the development of OCB

The Synthetic Potential of Fungal Feruloyl Esterases : A Correlation with Current Classification Systems and Predicted Structural Properties

Twenty-eight fungal feruloyl esterases (FAEs) were evaluated for their synthetic abilities in a ternary system of n-hexane: t-butanol: 100 mM MOPS-NaOH pH 6.0 forming detergentless microemulsions. Five main derivatives were synthesized, namely prenyl ferulate, prenyl caffeate, butyl ferulate, glyceryl ferulate, and l-arabinose ferulate, offering, in general, higher yields when more hydrophilic alcohol substitutions were used. Acetyl xylan esterase-related FAEs belonging to phylogenetic subfamilies (SF) 5 and 6 showed increased synthetic yields among tested enzymes. In particular, it was shown that FAEs belonging to SF6 generally transesterified aliphatic alcohols more efficiently while SF5 members preferred bulkier l-arabinose. Predicted surface properties and structural characteristics were correlated with the synthetic potential of selected tannase-related, acetyl-xylan-related, and lipase-related FAEs (SF1-2, -6, -7 members) based on homology modeling and small molecular docking simulations.Peer reviewe

CD44 isoforms are heterogeneously expressed in breast cancer and correlate with tumor subtypes and cancer stem cell markers

<p>Abstract</p> <p>Background</p> <p>The CD44 cell adhesion molecule is aberrantly expressed in many breast tumors and has been implicated in the metastatic process as well as in the putative cancer stem cell (CSC) compartment. We aimed to investigate potential associations between alternatively spliced isoforms of CD44 and CSCs as well as to various breast cancer biomarkers and molecular subtypes.</p> <p>Methods</p> <p>We used q-RT-PCR and exon-exon spanning assays to analyze the expression of four alternatively spliced CD44 isoforms as well as the total expression of CD44 in 187 breast tumors and 13 cell lines. ALDH1 protein expression was determined by IHC on TMA.</p> <p>Results</p> <p>Breast cancer cell lines showed a heterogeneous expression pattern of the CD44 isoforms, which shifted considerably when cells were grown as mammospheres. Tumors characterized as positive for the CD44⁺/CD24<it>^-</it>phenotype by immunohistochemistry were associated to all isoforms except the CD44 standard (CD44S) isoform, which lacks all variant exons. Conversely, tumors with strong expression of the CSC marker ALDH1 had elevated expression of CD44S. A high expression of the CD44v2-v10 isoform, which retain all variant exons, was correlated to positive steroid receptor status, low proliferation and luminal A subtype. The CD44v3-v10 isoform showed similar correlations, while high expression of CD44v8-v10 was correlated to positive EGFR, negative/low HER2 status and basal-like subtype. High expression of CD44S was associated with strong HER2 staining and also a subgroup of basal-like tumors. Unsupervised hierarchical cluster analysis of CD44 isoform expression data divided tumors into four main clusters, which showed significant correlations to molecular subtypes and differences in 10-year overall survival.</p> <p>Conclusions</p> <p>We demonstrate that individual CD44 isoforms can be associated to different breast cancer subtypes and clinical markers such as HER2, ER and PgR, which suggests involvement of CD44 splice variants in specific oncogenic signaling pathways. Efforts to link CD44 to CSCs and tumor progression should consider the expression of various CD44 isoforms.</p

Collaborative meta-analysis finds no evidence of a strong interaction between stress and 5-HTTLPR genotype contributing to the development of depression

The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research, and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 datasets containing 38 802 European-ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analyzed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis1) with qualifying unpublished data were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction, and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalizable, but must be of modest effect size and only observable in limited situations

Recent smell loss is the best predictor of COVID-19 among individuals with recent respiratory symptoms

In a preregistered, cross-sectional study we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n=4148) or negative (C19-; n=546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19- groups exhibited smell loss, but it was significantly larger in C19+ participants (mean±SD, C19+: -82.5±27.2 points; C19-: -59.8±37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC=0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0-10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4&lt;10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable