Biochemical and genetic implications of the slow ripening phenotype in peach fruit

The peach [Prunus persica L. (Batsch)] slow ripening (SR) trait is a mutation preventing the normal fruit ripening process. It is determined by a single Mendelian gene (Sr/sr) located on linkage group 4, where only homozygous individuals for a recessive allele (sr) show the SR phenotype and are generally discarded from breeding programs. Ripening-related traits such as fruit weight, firmness loss, ethylene production, ACO activity, sugars and organic acids composition, malondialdehyde, antioxidant capacity and total phenolic content were evaluated in a segregating population for the SR trait during two consecutive harvest seasons and at different maturity stages. Although there is no commercial value for the slow ripening (srsr) individuals, our results demonstrate that a heterozygous combination involving sr and another allele at this locus (Sr2) showed interesting traits including a longer harvest window and improved postharvest behaviour if harvested at the appropriate maturity (IAD ≥ 2). All these traits seem to be linked to a delayed ripening behaviour mediated, in turn, by a lower ethylene production capacity and an altered sugar (mainly sucrose) and organic acid accumulation/utilisation on-tree. The selection of this allelic combination could be an easy and efficient strategy to obtain new peach cultivars with potentially improved shelf life.info:eu-repo/semantics/acceptedVersio

Inheritance and QTL analysis of chilling and heat requirements for flowering in an interspecific almond x peach (Texas x Earlygold) F2 population

Blooming in temperate fruit species is triggered by chilling and heat requirements (CR and HR), with a wide range of requirements within the same species. CR for flower bud dormancy release has become a limiting factor for geographical adaptation of fruit trees in warmer regions. The present study investigated the genetic basis of CR and HR to break dormancy and flowering time (FT) in an almond x peach F2 progeny. FT, HR and CR were evaluated over two consecutive years (2015/2016 and 2016/2017). Seven out of the eight identified quantitative trait loci (QTLs) were found in both periods of analysis. They affected eight traits, and included a consistent QTL for breaking dormancy, CR and HR. Two of them, affecting FT and HR for FT (GDHF), colocalized in G1, and the remaining QTLs, affecting chilling and heat requirements, both influenced by dormancy breaking (DB), were located in G6. These results indicate that factors not related to DB affect flowering time in this population. Implications of the results in peach breeding are discussed.info:eu-repo/semantics/acceptedVersio

Using compositional mixed-effects models to evaluate responses to amino acid supplementation in milk replacers for calves

The consequences of supplementing Lys, Met, and Thr in milk replacers (MR) for calves have been widely studied, but scarce information exists about potential roles of other AA (whether essential or not). The effects on growth performance of supplementation of 4 different AA combinations in a mixed ration (25.4% crude protein and 20.3% fat) based on skim milk powder and whey protein concentrate were evaluated in 76 Holstein male calves (3 ± 1.7 d old). The 4 MR were as follows: CTRL with no AA supplementation; PG, supplying additional 0.3% Pro and 0.1% Gly; FY, supplying additional 0.2% Phe and 0.2% Tyr; and KMT, providing additional 0.62% Lys, 0.22% Met, and 0.61% Thr. All calves were fed the same milk allowance program and were weaned at 56 d of study. Concentrate intake was limited to minimize interference of potential differences in solid feed intake among treatments. Animals were weighed weekly, intakes recorded daily, and blood samples obtained at 2, 5, and 7 wk of study to determine serum urea and plasma AA concentrations. Plasma AA concentrations were explored using compositional data analysis, and their isometric log-ratio transformations were used to analyze their potential influence on ADG and serum urea concentration using a linear mixed-effects model. We detected no differences in calf performance and feed intake. Plasma relative concentration of the AA supplemented in the KMT and PG treatments increased in their respective treatments, and, in PG calves, a slight increase in the proportion of plasma Gly, Glu, and branched-chain AA was also observed. The proportions of plasma branched-chain AA, His, and Gln increased, and those of Thr, Arg, Lys, and Glu decreased with calves' age. A specific log-contrast balance formed by Arg, Thr, and Lys was found to be the main driver for lowering serum urea concentrations and increasing calf growth. The use of compositional mixed-effects models identified a cluster formed by the combination of Arg, Thr, and Lys, as a potential AA to optimize calf growth.Peer ReviewedPostprint (published version

Inheritance and QTL analysis of chilling and heat requirements for flowering in an interspecific almond x peach (Texas x Earlygold) F2 population

Altres ajuts: Generalitat de Catalunya/CERCA programmeBlooming in temperate fruit species is triggered by chilling and heat requirements (CR and HR), with a wide range of requirements within the same species. CR for flower bud dormancy release has become a limiting factor for geographical adaptation of fruit trees in warmer regions. The present study investigated the genetic basis of CR and HR to break dormancy and flowering time (FT) in an almond x peach F2 progeny. FT, HR and CR were evaluated over two consecutive years (2015/2016 and 2016/2017). Seven out of the eight identified quantitative trait loci (QTLs) were found in both periods of analysis. They affected eight traits, and included a consistent QTL for breaking dormancy, CR and HR. Two of them, affecting FT and HR for FT (GDHF), colocalized in G1, and the remaining QTLs, affecting chilling and heat requirements, both influenced by dormancy breaking (DB), were located in G6. These results indicate that factors not related to DB affect flowering time in this population. Implications of the results in peach breeding are discussed

Identification of an Archaeal Presenilin-Like Intramembrane Protease

BACKGROUND: The GXGD-type diaspartyl intramembrane protease, presenilin, constitutes the catalytic core of the γ-secretase multi-protein complex responsible for activating critical signaling cascades during development and for the production of β-amyloid peptides (Aβ) implicated in Alzheimer's disease. The only other known GXGD-type diaspartyl intramembrane proteases are the eukaryotic signal peptide peptidases (SPPs). The presence of presenilin-like enzymes outside eukaryots has not been demonstrated. Here we report the existence of presenilin-like GXGD-type diaspartyl intramembrane proteases in archaea. METHODOLOGY AND PRINCIPAL FINDINGS: We have employed in vitro activity assays to show that MCMJR1, a polytopic membrane protein from the archaeon Methanoculleus marisnigri JR1, is an intramembrane protease bearing the signature YD and GXGD catalytic motifs of presenilin-like enzymes. Mass spectrometry analysis showed MCMJR1 could cleave model intramembrane protease substrates at several sites within their transmembrane region. Remarkably, MCMJR1 could also cleave substrates derived from the β-amyloid precursor protein (APP) without the need of protein co-factors, as required by presenilin. Two distinct cleavage sites within the transmembrane domain of APP could be identified, one of which coincided with Aβ40, the predominant site processed by γ-secretase. Finally, an established presenilin and SPP transition-state analog inhibitor could inhibit MCMJR1. CONCLUSIONS AND SIGNIFICANCE: Our findings suggest that a primitive GXGD-type diaspartyl intramembrane protease from archaea can recapitulate key biochemical properties of eukaryotic presenilins and SPPs. MCMJR1 promises to be a more tractable, simpler system for in depth structural and mechanistic studies of GXGD-type diaspartyl intramembrane proteases

Fine mapping of the peach pollen sterility gene (Ps/ps) and detection of markers for marker-assisted selection

Altres ajuts: CERCA Programme/Generalitat de CatalunyaIn peach, pollen sterility, expressed as absence of pollen in the anthers, segregates as an undesired trait in breeding programs. Pollen fertility screening in progenies is not a common practice mainly because it does not affect fruit set since cross-pollination is frequent. It is also a time-consuming activity that coincides with the busy pollination season. Segregation for this trait could be avoided by using molecular markers to identify appropriate parents or male sterile plants for early culling in progenies expected to segregate, thus increasing breeding efficiency. In peach, pollen sterility is determined by a recessive allele in homozygosis of the major gene, Ps/ps, located on chromosome 6. In this work, using a conventional mapping approach combined with bulked segregant analysis using resequencing data, we fine mapped Ps to a region of almost 160 kb and developed molecular markers for marker-assisted breeding. These markers were validated in plant materials from three peach breeding programs, including progenies, advanced selections and cultivars, allowing us to determine that the frequency of the ps allele is high (0.23) and also to infer the genotypes of a large collection of cultivars and advanced breeding lines

Flat Peach SUBLOR and SUBLIM and Flat Nectarine PERLA Series

Flat peach and flat nectarine (Prunus persica L. Batsch.) production in Spain started from local cultivars at marginal sites, mainly in the Ebro Valley and Murcia regions. At the end of the 1990s, the introduction of improved cultivars from France and Italy, with more red skin color coverage and better regular shape, fruit size, and stylar cavity closure, together with superior handling and transport conditions led the Spanish peach sector to develop this fruit type on a commercial scale. Currently, Spain is the largest European producer and exporter of flat peach and nectarine, offering a wide range of cultivars covering the producing period from May to September. In 2020, a total of 10.200 ha for flat peach and 481 ha for flat nectarine together produced 263.651 t (20% of the total peach production) (MAPAMA, 2022). To guarantee adaptation to local growing conditions (Font i Forcada et al., 2021a), several national breeding programs started to develop new flat peach and flat nectarine cultivars. One of these breeding programs is the ASF-IRTA breeding program, which is located at Gimenells (Lleida) in the Ebro Valley (northeastern Spain), which is a major region of peach production in Spain (Batlle et al., 2012; Cantín et al., 2017). It was started in 2004, with the objective of developing new cultivars adapted to chilling between 1000 and 1500 chill units or between 42 and 75 chill portions and warm conditions similar to the Mediterranean area (32 °C mean daily summer temperature and 300–400 mm of annual rainfall). It aimed to produce high-quality fruits, both at harvest and after cold storage, with the ultimate goal of satisfying consumers (Font i Forcada et al., 2021a, 2021b). As a result of this collaborative effort, the ASF-IRTA scion peach breeding program has already released the SUBLOR (one flat yellow-fleshed peach), SUBLIM (six flat white-fleshed peach), and PERLA (two flat white-fleshed nectarine) series. These nine new flat peach and nectarine cultivars produce highly attractive yellow-fleshed or white-fleshed fruits with high coverage of red skin, a balanced or acid flavor, sweet taste, and good flesh firmness. The harvesting calendar of these series will be progressively completed with new future releases.info:eu-repo/semantics/publishedVersio

Analysis of Mercury Content in Canned Tuna Fish Commercially Available in the Philippines

Objective: To analyze the total concentration (in mg/kg) of Mercury in Canned Tuna Fish commercially available in the Philippines, using Cold Vapor Atomic Absorption Spectrophotometry (CVAAS) and to compare the results gathered with permissible FAO/WHO levels. Background: The levels of the toxic heavy metal, mercury have not been previously determined in canned Tuna commercially available in the Philippines. Methods: Six different brands of canned tuna, commercially and widely available in the Philippines were selected. The samples were primed, then analyzed using Cold Vapor Atomic Absorption Spectrophotometry. The values obtained were then compared the tolerable weekly limit of Mercury as set by WHO. Results: Of the six canned tuna, all were tested positive for mercury. The mercury content expressed in mg/kg body weight were 0.10, 0.04, 0.06, 0.02, 0.02, and 0.02, for samples A, B, C, D, E and F respectively. The Provisional Tolerable Weekly intake of total mercury is 0.004 mg/kg, as set by the Food and Agriculture Organization/World Health Organization Joint Expert Committee on Food Additives [1]. The recovered mercury from all the canned tunas tested were well above the Provisional Tolerable Weekly Intake of total Mercury [1]. Conclusion: All of the 6 cans of tuna samples tested were positive for mercury well above the permissible FAO/WHO levels for mercury. Therefore, the analysis of the canned tuna is considered significant and the canned tuna fish seem to be unsafe for human consumption

Homozygous R136S mutation in PRNP gene causes inherited early onset prion disease

Altres ajuts: Fundació la Marató de TV3/201821-31Background: More than 40 pathogenic heterozygous PRNP mutations causing inherited prion diseases have been identified to date. Recessive inherited prion disease has not been described to date. Methods: We describe the clinical and neuropathological data of inherited early-onset prion disease caused by the rare PRNP homozygous mutation R136S. In vitro PrP propagation studies were performed using recombinant-adapted protein misfolding cyclic amplification technique. Brain material from two R136S homozygous patients was intracranially inoculated in TgMet129 and TgVal129 transgenic mice to assess the transmissibility of this rare inherited form of prion disease. Results: The index case presented symptoms of early-onset dementia beginning at the age of 49 and died at the age of 53. Neuropathological evaluation of the proband revealed abundant multicentric PrP plaques and Western blotting revealed a ~ 8 kDa protease-resistant, unglycosylated PrP fragment, consistent with a Gerstmann-Sträussler-Scheinker phenotype. Her youngest sibling suffered from progressive cognitive decline, motor impairment, and myoclonus with onset in her late 30s and died at the age of 48. Genetic analysis revealed the presence of the R136S mutation in homozygosis in the two affected subjects linked to homozygous methionine at codon 129. One sibling carrying the heterozygous R136S mutation, linked to homozygous methionine at codon 129, is still asymptomatic at the age of 74. The inoculation of human brain homogenates from our index case and an independent case from a Portuguese family with the same mutation in transgenic mice expressing human PrP and in vitro propagation of PrP studies failed to show disease transmissibility. Conclusion: In conclusion, biallelic R136S substitution is a rare variant that produces inherited early-onset human prion disease with a Gerstmann-Sträussler-Scheinker neuropathological and molecular signature. Even if the R136S variant is predicted to be "probably damaging", heterozygous carriers are protected, at least from an early onset providing evidence for a potentially recessive pattern of inheritance in human prion diseases

Molecularly determined total tumour load in lymph nodes of stage I–II colon cancer patients correlates with high-risk factors. A multicentre prospective study

Stage I–II (pN0) colorectal cancer patients are surgically treated although up to 25 % will eventually die from disease recurrence. Lymph node (LN) status is an independent prognostic factor in colorectal cancer (CRC), and molecular tumour detection in LN of early-stage CRC patients is associated with an increased risk of disease recurrence and poor survival. This prospective multicentre study aimed to determine the relationship between LN molecular tumour burden and conventional high-risk factors in stage I–II colon cancer patients. A total of 1940 LN from 149 pathologically assessed pN0 colon cancer patients were analysed for the amount of tumour cytokeratin 19 (CK19) messenger RNA (mRNA) with the quantitative reverse transcription loop-mediated isothermal amplification molecular assay One-Step Nucleic Acid Amplification. Patient’s total tumour load (TTL) resulted from the sum of all CK19 mRNA tumour copies/μL of each positive LN from the colectomy specimen. A median of 15 LN were procured per case (IQR 12;20). Molecular positivity correlated with high-grade (p < 0.01), mucinous/signet ring type (p = 0.017), male gender (p = 0.02), number of collected LN (p = 0.012) and total LN weight per case (p < 0.01). The TTL was related to pT stage (p = 0.01) and tumour size (p < 0.01) in low-grade tumours. Multivariate logistic regression showed independent correlation of molecular positivity with gender, tumour grade and number of fresh LN [AUC = 0.71 (95 % CI = 0.62–0.79)]. Our results show that lymph node CK19 mRNA detection correlates with classical high-risk factors in stage I–II colon cancer patients. Total tumour load is a quantitative and objective measure that may help to better stage early colon cancer patients.Work supported by the Banc de Tumors-Biobanc Hospital Clinic-IDIBAPS and Xarxa de Bancs de Tumors de Catalunya (XBTC), and by grants from the Fundación Científica de la Asociación Española Contra el Cáncer (GCB13131592CAST), Ministerio de Economía y Competitividad (SAF2014–54,453-R), Agència de Gestió d’Ajuts Universitaris i de Recerca (2014SGR135), and by Sysmex Coorp Spain (Sant Just Desvern, Spain). CIBERehd is funded by the Instituto de Salud Carlos II