Antibiotic treatment after appendectomy for acute complicated appendicitis to prevent intrabdominal abscess and wound infections.

INTRODUCTION: The purpose of this analysis was to investigate the most appropriate duration of postoperative antibiotic treatment to minimize the incidence of intraabdominal abscesses and wound infections in patients with complicated appendicitis. MATERIALS AND METHODS: In this retrospective study, which included 396 adult patients who underwent appendectomy for complicated appendicitis between January 2010 and December 2020 at the University Hospital Erlangen, patients were classified into two groups based on the duration of their postoperative antibiotic intake: ≤ 3 postoperative days (group 1) vs. ≥ 4 postoperative days (group 2). The incidence of postoperative intraabdominal abscesses and wound infections were compared between the groups. Additionally, multivariate risk factor analysis for the occurrence of intraabdominal abscesses and wound infections was performed. RESULTS: The two groups contained 226 and 170 patients, respectively. The incidence of postoperative intraabdominal abscesses (2% vs. 3%, p = 0.507) and wound infections (3% vs. 6%, p = 0.080) did not differ significantly between the groups. Multivariate analysis revealed that an additional cecum resection (OR 5.5 (95% CI 1.4-21.5), p = 0.014) was an independent risk factor for intraabdominal abscesses. A higher BMI (OR 5.9 (95% CI 1.2-29.2), p = 0.030) and conversion to an open procedure (OR 5.2 (95% CI 1.4-20.0), p = 0.016) were identified as independent risk factors for wound infections. CONCLUSION: The duration of postoperative antibiotic therapy does not appear to influence the incidence of postoperative intraabdominal abscesses and wound infections. Therefore, short-term postoperative antibiotic treatment should be preferred.

Quality of life of families and siblings of children with cerebral palsy treated at a reference neurorehabilitation center in Brazil.

OBJECTIVES: To investigate the associations between caregivers' burden, family quality of life (QoL), and siblings' QoL in Brazilian families of children with cerebral palsy, and to analyze siblings' QoL using as a parameter the QoL of typically developed Brazilian children. METHODS: It was a cross-sectional study. The 212 families, 212 caregivers and 131 siblings completed the Family Quality of Life Scale, Burden Interview, and KIDSCREEN-27 Child and Adolescent Version and Parents Version questionnaires at a neurorehabilitation center in southeast Brazil. Univariable and multivariable models were used. RESULTS: Family QoL significantly worsened as caregivers' burden increased (95 % CI -0.66 to -0.38). Caregivers' burden was significantly lower with increasing family QoL scores (95 % CI -0.52 to -0.30). Self-reported siblings' QoL was significantly worse than that of their typically developed peers (95 % CI -7.6 to -3.6). Self-reported siblings' QoL was significantly lower as siblings' age (95 % CI -2.52 to -0.59) and caregivers' burden (95 % CI -0.35 to -0.05) increased. Parent-reported siblings' QoL was significantly lower with increasing caregivers' burden (95 % CI -0.45 to -0.16) and higher as family QoL increased (95 % CI 0.09 to 0.37). CONCLUSIONS: The cross-sectional nature of these data precludes any statement of causality. Family QoL worsened with higher caregivers' burden levels. Lower caregivers' burden scores were associated with a higher family QoL. Siblings' QoL was impaired as compared to typically developed peers, worse among older siblings, and as caregivers' burden increased and better with higher family QoL levels. Future multicenter studies may validate the generalizability of the present findings.

A Case Study of a Rare Undifferentiated Spindle Cell Sarcoma of the Penis: Establishment and Characterization of Patient-Derived Models.

Rare sarcomas present significant treatment challenges compared to more prevalent soft tissue sarcomas due to limited treatment options and a poor understanding of their biology. This study investigates a unique case of penile sarcoma, providing a comprehensive morphological and molecular analysis. Through the creation of experimental patient-derived models-including patient-derived xenograft (PDX), 3D, and monolayer primary cultures-we successfully replicated crucial molecular traits observed in the patient's tumor, such as smooth muscle actin and CD99 expression, along with specific mutations in genes like TSC2 and FGFR4. These models are helpful in assessing the potential for an in-depth exploration of this tumor's biology. This comprehensive approach holds promise in identifying potential therapeutic avenues for managing this exceedingly rare soft tissue sarcoma.

Quality of life of families and siblings of children and adolescents with meningomyelocele.

BACKGROUND: Children with meningomyelocele may require continuous care. Consequently, there is a risk for caregiver burden and impact on family quality of life (QoL), including siblings' QoL. Some studies analysed caregivers' burden and family QoL separately. However, none of these studies evaluated siblings' QoL and the associations between these three dimensions. This study investigated the associations between caregivers' burden, family QoL and siblings' QoL in Brazilian families of children with meningomyelocele and its correlations with sociodemographic, functional and clinical variables. Siblings' QoL was specifically assessed using as a parameter the QoL of typically developed Brazilian children. METHODS: One hundred and fifty families, 150 caregivers and 68 siblings completed the Family Quality of Life Scale, Burden Interview, KIDSCREEN-27 Child and Adolescent Version and Parents Version questionnaires. RESULTS: Most families and caregivers reported a high family QoL and a low caregiver burden. Family QoL was significantly lower as caregivers' burden increased. Caregiver's burden was significantly lower with increasing family QoL levels. Self-reported siblings' QoL was significantly worse than that of typically developed peers. There were no significant differences between self and parent-reported siblings' QoL. Self-reported siblings' QoL was significantly worse as their age increased and better with increasing family QoL levels. Parent-reported siblings' QoL was significantly worse with increasing levels of caregiver's burden and significantly better as family QoL increased. There were no significant associations with functional and clinical variables. CONCLUSIONS: Despite the cross-sectional nature of the available data precludes any statements of causality, our results reinforce the relevance of knowing the factors that influence the QoL of families and siblings of children and adolescents with meningomyelocele and the relevance of actions aimed at reducing caregivers' burden, improving family QoL and meeting siblings' individual needs. Future multicenter studies may validate the generalizability of our findings.

Development of pollinated and unpollinated ovules in Ginkgo biloba: unravelling the role of pollen in ovule tissue maturation.

In gymnosperms such as Ginkgo biloba, the arrival of pollen plays a key role in ovule development, before fertilization occurs. Accordingly, G. biloba female plants geographically isolated from male plants abort all their ovules after the pollination drop emission, which is the event that allows the ovule to capture pollen grains. To decipher the mechanism induced by pollination required to avoid ovule senescence and then abortion, we compared the transcriptomes of pollinated and unpollinated ovules at three time points after the end of the emission of pollination drop. Transcriptomic and in situ expression analyses revealed that several key genes involved in programmed cell death such as senescence and apoptosis, DNA replication, and cell cycle regulation were differentially expressed in unpollinated ovules compared to pollinated ovules. We provide evidence that the pollen captured by the pollination drop affects auxin local accumulation and might cause deregulation of key genes required for the ovule's programmed cell death, activating both the cell cycle regulation and DNA replication genes.

Reflections about the conceptual bases of Geotourism and its sub-segments Space Geotourism, Celestial Geotourism and Astrotourism to create a univocal definition.

The concept is part of the essence of a mentally represented element. The concept is part of the process of identification, categorization and description, which allows researchers to define and compare themes between two or more different categories. Following this idea, the main objective of this article is to establish a non-exhaustive reflection on the conceptual bases of Geotourism and its sub-segments Celestial Geotourism, Space Geotourism and Astrotourism. The main reason for carrying out this research is because there isn't a one definition yet for the terms. This is perhaps the reason for the conflicts that exist between the themes of this tourism practice and the three categories - Celestial Geotourism, Space Geotourism and Astrotourism. The methodology was developed through secondary sources and based on the results obtained, it was possible to identify and distinguish the most important concepts to establish a univocal operational definition for each term. Finally, it was possible to conclude that although there are conflicts, this happens due to the inadequate interpretative representation of the themes between the categories.

The role of intraoperative swab during appendectomy in patients with uncomplicated and complicated appendicitis.

INTRODUCTION: Bacteria play an important role not only in pathogenesis of appendicitis but also in the postoperative course of patients. However, the usefulness of an intraoperative swab during appendectomy is controversial. The primary aim of this study was to investigate the impact of intraoperative swab during appendectomy on the postoperative outcome in patients with uncomplicated and complicated appendicitis. METHODS: A retrospective analysis was conducted on a consecutive series of 1570 adult patients who underwent appendectomy for acute appendicitis at the University Hospital Erlangen between 2010 and 2020. Data regarding the intraoperative swab were collected and analyzed for the entire cohort as well as for patients with uncomplicated and complicated appendicitis. RESULTS: An intraoperative swab was taken in 29% of the cohort. The bacterial isolation rate in the obtained intraoperative swabs was 51%, with a significantly higher rate observed in patients with complicated appendicitis compared to those with uncomplicated appendicitis (79% vs. 35%, p < 0.001). The presence of a positive swab was significantly associated with worse postoperative outcomes, including higher morbidity, increased need for re-surgery, and longer hospital stay, when compared to patients without a swab or with a negative swab. A positive swab was an independent risk factor for postoperative morbidity (OR 9.9 (95% CI 1.2-81.9), p = 0.034) and the need for adjustment of postoperative antibiotic therapy (OR 8.8 (95% CI 1.1-72.5), p = 0.043). However, a positive swab resulted in postoperative antibiotic therapy adjustment in only 8% of the patients with bacterial isolation in the swab. CONCLUSION: The analysis of swab samples obtained during appendectomy for acute appendicitis can help identify patients at a higher risk of a worse postoperative outcome. However, the frequency of antibiotic regime changes based on the swab analysis is low.

A Study of GUS Expression in Arabidopsis as a Tool for the Evaluation of Gene Evolution, Function and the Role of Expression Derived from Gene Duplication.

Gene duplication played a fundamental role in eukaryote evolution and different copies of a given gene can be present in extant species, often with expressions and functions differentiated during evolution. We assume that, when such differentiation occurs in a gene copy, this may be indicated by its maintenance in all the derived species. To verify this hypothesis, we compared the histological expression domains of the three ß-glucuronidase genes (AtGUS) present in Arabidopsis thaliana with the GUS evolutionary tree in angiosperms. We found that AtGUS gene expression overlaps in the shoot apex, the floral bud and the root hairs. In the root apex, AtGUS3 expression differs completely from AtGUS1 and AtGUS2, whose transcripts are present in the root cap meristem and columella, in the staminal cell niche, in the epidermis and in the proximal cortex. Conversely, AtGUS3 transcripts are limited to the old border-like cells of calyptra and those found along the protodermal cell line. The GUS evolutionary tree reveals that the two main clusters (named GUS1 and GUS3) originate from a duplication event predating angiosperm radiation. AtGUS3 belongs to the GUS3 cluster, while AtGUS1 and AtGUS2, which originate from a duplication event that occurred in an ancestor of the Brassicaceae family, are found together in the GUS1 cluster. There is another, previously undescribed cluster, called GUS4, originating from a very ancient duplication event. While the copy of GUS4 has been lost in many species, copies of GUS3 and GUS1 have been conserved in all species examined.

Daily ROX index can predict transitioning to mechanical ventilation within the next 24 h in COVID-19 patients on HFNC.

INTRODUCTION: High flow nasal cannula (HFNC) is used to prevent invasive ventilation in COVID-19-associated hypoxemia. The respiratory rate­oxygenation (ROX) index has been reported to predict failure of HFNC in patients with COVID-19 pneumonia during the intensive care unit stay when measured in first hours of therapy. However, the clinical course of ICU patients may change substantially in the first days of admission. The objective of this study was to investigate whether ROX index obtained in the first four days of ICU admission could predict the need for invasive respiratory support within the next 24 h of measurements. METHODS: A retrospective cross-sectional study was performed using a database that included adult patients with COVID-19 pneumonia treated in the ICU. Patients were followed from ICU admission and ROX index was calculated daily on HFNC. Receiver operating characteristics curves (ROCs) were performed. RESULTS: Two hundred forty-nine patients were enrolled, 48% of whom require mechanical ventilation (MV). The area under the ROC of the pooled 4-day values of the ROX index as a predictor of transition from HFNC to MV within 24 h of measurements was 0.86 (95%CI 0.83 to 0.88, P < 0.001) with a cutoff point of 4.06. CONCLUSION: In COVID-19 patients in high flow nasal cannula, daily ROX index measurements successfully predicted transition to mechanical ventilation within the next 24 h.

Risk Factors for Conversion from Laparoscopic to Open Appendectomy.

(1) Background: Since its introduction in the 1990s, laparoscopic appendectomy has become established over the years and is today considered the standard therapy for acute appendicitis. In some cases, however, a conversion to the open approach is still necessary. The primary aim of this study was to identify risk factors for the need to convert from the laparoscopic to an open approach during appendectomy for acute appendicitis. (2) Methods: A retrospective analysis of 1220 adult patients who underwent laparoscopic appendectomy for acute appendicitis from 2010 to 2020 at the University Hospital Erlangen was performed. Data, including patient demographics and pre-, intra-, and postoperative findings, were collected and compared between patients with and without conversion. (3) Results: The conversion rate in our cohort was 5.5%. A higher preoperative WBC count and CRP (OR 1.9, p = 0.042, and OR 2.3, p = 0.019, respectively), as well as the presence of intraoperative perforation, necrosis or gangrene, perityphlitic abscess and peritonitis (OR 3.2, p = 0.001; OR 2.3, p = 0.023; OR 2.6, p = 0.006 and OR 2.0, p = 0.025, respectively) were identified as independent risk factors for conversion from the laparoscopic to the open approach. Conversion was again independently associated with higher morbidity (OR 2.2, p = 0.043). (4) Conclusion: The laparoscopic approach is feasible and safe in the majority of patients with acute appendicitis. Only increased inflammatory blood markers could be detected as the preoperative risk factors potentially influencing the choice of surgical approach but only with low specificity and sensitivity. For the decision to convert, intraoperative findings are additionally crucial. However, patients with conversion should receive special attention in the postoperative course, as these have an increased risk of developing complications.

Modulation of Anthocyanin Biosynthesis-Related Genes during the Ripening of Olea europaea L. cvs Carolea and Tondina Drupes in Relation to Environmental Factors.

Anthocyanins protect plants against various biotic and abiotic stresses, and anthocyanin-rich foods exert benefits on human health due to their antioxidant activity. Nevertheless, little information is available on the influence of genetic and environmental factors on the anthocyanin content in olive fruits. Based on this consideration, the total anthocyanin content, the genes involved in anthocyanin biosynthesis, and three putative R2R3-MYB transcription factors were evaluated at different ripening stages in the drupes of the Carolea and Tondina cultivars, sampled at different altitudes in the Calabria region, Italy. During drupe ripening, the total anthocyanin content and the transcript levels of analyzed genes gradually increased. In line with the anthocyanin content, a different level of expression of anthocyanin structural genes was observed in 'Carolea' compared to 'Tondina', and in relation to the cultivation area. Furthermore, we identified Oeu050989.1 as a putative R2R3-MYB involved in the regulation of anthocyanin structural genes correlated with the environmental temperature change response. We conclude that anthocyanin accumulation is strongly regulated by development, genotype, and also by environmental factors such as temperature, associated with the altitude gradient. The obtained results contribute to reducing the current information gap regarding the molecular mechanisms on anthocyanin biosynthesis regulation related to the environmental conditions in Olea europaea.

Short-term exposition to acute cadmium toxicity induces the loss of root gravitropic stimuli perception through PIN2-mediated auxin redistribution in Arabidopsis thaliana (L.) Heynh.

Cadmium (Cd), one of the most widespread and water-soluble polluting heavy metals, has been widely studied on plants, even if the mechanisms underlying its phytotoxicity remain elusive. Indeed, most experiments are performed using extensive exposure time to the toxicants, not observing the primary targets affected. The present work studied Cd effects on Arabidopsis thaliana (L.) Heynh's root apical meristem (RAM) exposed for short periods (24 h and 48 h) to acute phytotoxic concentrations (100 and 150 µM). The effects were studied through integrated morpho-histological, molecular, pharmacological and metabolomic analyses, highlighting that Cd inhibited primary root elongation by affecting the meristem zone via altering cell expansion. Moreover, Cd altered Auxin accumulation in RAM and affected PINs polar transporters, particularly PIN2. In addition, we observed that high Cd concentration induced accumulation of reactive oxygen species (ROS) in roots, which resulted in an altered organization of cortical microtubules and the starch and sucrose metabolism, altering the statolith formation and, consequently, the gravitropic root response. Our results demonstrated that short Cd exposition (24 h) affected cell expansion preferentially, altering auxin distribution and inducing ROS accumulation, which resulted in an alteration of gravitropic response and microtubules orientation pattern.

Positive end-expiratory pressure induced changes in airway driving pressure in mechanically ventilated COVID-19 Acute Respiratory Distress Syndrome patients.

BACKGROUND: The profile of changes in airway driving pressure (dPaw) induced by positive-end expiratory pressure (PEEP) might aid for individualized protective ventilation. Our aim was to describe the dPaw versus PEEP curves behavior in ARDS from COVID-19 patients. METHODS: Patients admitted in three hospitals were ventilated with fraction of inspired oxygen (FiO2) and PEEP initially adjusted by oxygenation-based table. Thereafter, PEEP was reduced from 20 until 6 cmH2O while dPaw was stepwise recorded and the lowest PEEP that minimized dPaw (PEEPmin_dPaw) was assessed. Each dPaw vs PEEP curve was classified as J-shaped, inverted-J-shaped, or U-shaped according to the difference between the minimum dPaw and the dPaw at the lowest and highest PEEP. In one hospital, hyperdistention and collapse at each PEEP were assessed by electrical impedance tomography (EIT). RESULTS: 184 patients (41 including EIT) were studied. 126 patients (68%) exhibited a J-shaped dPaw vs PEEP profile (PEEPmin_dPaw of 7.5 ± 1.9 cmH2O). 40 patients (22%) presented a U (PEEPmin_dPaw of 12.2 ± 2.6 cmH2O) and 18 (10%) an inverted-J profile (PEEPmin_dPaw of 14,6 ± 2.3 cmH2O). Patients with inverted-J profiles had significant higher body mass index (BMI) and lower baseline partial pressure of arterial oxygen/FiO2 ratio. PEEPmin_dPaw was associated with lower fractions of both alveolar collapse and hyperinflation. CONCLUSIONS: A PEEP adjustment procedure based on PEEP-induced changes in dPaw is feasible and may aid in individualized PEEP for protective ventilation. The PEEP required to minimize driving pressure was influenced by BMI and was low in the majority of patients.

DNA Methylation in Algae and Its Impact on Abiotic Stress Responses.

Epigenetics, referring to heritable gene regulatory information that is independent of changes in DNA sequences, is an important mechanism involved both in organism development and in the response to environmental events. About the epigenetic marks, DNA methylation is one of the most conserved mechanisms, playing a pivotal role in organism response to several biotic and abiotic stressors. Indeed, stress can induce changes in gene expression through hypo- or hyper-methylation of DNA at specific loci and/or in DNA methylation at the genome-wide level, which has an adaptive significance and can direct genome evolution. Exploring DNA methylation in responses to abiotic stress could have important implications for improving stress tolerance in algae. This article summarises the DNA methylation pattern in algae and its impact on abiotic stress, such as heavy metals, nutrients and temperature. Our discussion provides information for further research in algae for a better comprehension of the epigenetic response under abiotic stress, which could favour important implications to sustain algae growth under abiotic stress conditions, often related to high biosynthesis of interesting metabolites.

Short-Term Effects of Trans-Cinnamic Acid on the Metabolism of Zea mays L. Roots.

trans-Cinnamic acid is a phenolic compound widely studied in plant metabolism due to its importance in regulating different plant processes. Previous studies on maize plants showed that this compound could affect plant growth and causes metabolic changes in the leaves when applied. However, its effects on root metabolism are not well known. This study analyses the short-term effect of trans-cinnamic acid on the morphology of vascular bundle elements and metabolism in maize roots. At short times (between 6 and 12 h), there is a reduction in the content of many amino acids which may be associated with the altered nitrogen uptake observed in earlier work. In addition, the compound caused an alteration of the vascular bundles at 48 h and seemed to have changed the metabolism in roots to favor lignin and galactose synthesis. The results obtained complement those previously carried out on maize plants, demonstrating that in the short term trans-cinnamic acid can trigger stress-coping processes in the treated plants.

Risk factors for postoperative morbidity, prolonged length of stay and hospital readmission after appendectomy for acute appendicitis.

PURPOSE: The aim of the present study was to identify risk factors associated with postoperative morbidity and major morbidity, with a prolonged length of hospital stay and with the need of readmission in patients undergoing appendectomy due to acute appendicitis. METHODS: We performed a retrospective analysis of 1638 adult patients who underwent emergency appendectomy for preoperatively suspected acute appendicitis from 2010 to 2020 at the University Hospital Erlangen. Data including patient demographics, pre-, intra-, and postoperative findings were collected and compared between different outcome groups (morbidity, major morbidity, prolonged length of postoperative hospital stay (LOS) and readmission) from those patients with verified acute appendicitis (n = 1570). RESULTS: Rate of negative appendectomies was 4%. In patients with verified acute appendicitis, morbidity, major morbidity and readmission occurred in 6%, 3% and 2%, respectively. Mean LOS was 3.9 days. Independent risk factors for morbidity were higher age, higher preoperative WBC-count and CRP, lower preoperative hemoglobin, longer time to surgery and longer duration of surgery. As independent risk factors for major morbidity could be identified higher age, higher preoperative CRP, lower preoperative hemoglobin and longer time to surgery. Eight parameters were independent risk factors for a prolonged LOS: higher age, higher preoperative WBC-count and CRP, lower preoperative hemoglobin, need for conversion, longer surgery duration, presence of intraoperative complicated appendicitis and of postoperative morbidity. Presence of malignancy and higher preoperative WBC-count were independent risk factors for readmission. CONCLUSION: Among patients undergoing appendectomy for acute appendicitis, there are relevant risk factors predicting postoperative complications, prolonged hospital stays and readmission. Patients with the presence of the identified risk factors should receive special attention in the postoperative course and may benefit from a more individualized therapy.

Eco-Friendly Silver Nanoparticles Synthesized from a Soybean By-Product with Nematicidal Efficacy against Pratylenchus brachyurus.

This study explores an eco-friendly approach to synthesizing silver nanoparticles (AgNPs) using soybean leaf extracts, employing a reaction with silver nitrate at 65 °C for 2.5 h. Optimal results were achieved at extract concentrations of 3.12 and 6.25 mg of the leaf mL-1, termed 3.12AgNP and 6.25AgNP, respectively. UV-Vis spectrophotometric analysis between 350 and 550 nm exhibited a peak at 410-430 nm, along with a color transition in the suspensions from pale yellow to brown, indicating successful synthesis. Dynamic light scattering (DLS) further delineated the favorable properties of these AgNPs, including nanometric dimensions (73-104 nm), negative charge, and moderate polydispersity, portraying stable and reproducible synthesis reactions. The bioreduction mechanism, possibly expedited by leaf extract constituents such as amino acids, phenolic acids, and polysaccharides, remains to be fully elucidated. Notably, this study underscored the potent nematicidal effectiveness of biosynthesized AgNPs, especially 6.25AgNP, against Pratylenchus brachyurus, which is a common plant-parasitic nematode in tropical soybean cultivation regions. In vitro tests illustrated significant nematicidal activity at concentrations above 25 µmol L-1, while in vivo experiments displayed a pronounced nematode population diminishment in plant roots, particularly with a 6.25AgNP rhizosphere application at concentrations of 500 µmol L-1 or twice at 250 µmol L-1, attaining a reproduction factor below 1 without any morphological nematode alterations. This research highlights the potential of 6.25AgNPs derived from soybean leaf extracts in forging sustainable nematicidal solutions, marking a significant stride toward eco-friendly phytonematode management in soybean cultivation. This novel methodology signals a promising avenue in harnessing botanical resources for nematode control and propelling a greener agricultural horizon.

Early intervention in psoriasis: Where do we go from here?

Patients with psoriasis often have comorbidities and are at increased risk of developing several complications compared with the general population. Knowledge on the role of immune mediators and systemic inflammation in psoriasis has led to the hypothesis that early intervention with systemic therapy has the potential to modify the course of the disease and reduce the risk of long-term adverse outcomes. In this article, we address some potential issues that need to be considered before early intervention can be implemented routinely. The first is determining what constitutes "early" intervention for psoriasis. A second point is whether the intervention should be considered for patients with early disease or for selected subsets based on risk stratification. A third important consideration is defining success for early intervention. Finally, adoption of early and effective intervention should be based on high-level evidence. Ideally, randomized trials would be the best strategy to compare early vs. late systemic treatment in patients with psoriasis, probably using the frequency of long-term outcomes as primary endpoint, with cutaneous and pharmacoeconomic outcomes assessed secondarily.

Comparative transcriptomic profiling of peach and nectarine cultivars reveals cultivar-specific responses to chilled postharvest storage.

Introduction: Peach (Prunus persica (L.) Batsch,) and nectarine fruits (Prunus persica (L.) Batsch, var nectarine), are characterized by a rapid deterioration at room temperature. Therefore, cold storage is widely used to delay fruit post-harvest ripening and extend fruit commercial life. Physiological disorders, collectively known as chilling injury, can develop typically after 3 weeks of low-temperature storage and affect fruit quality. Methods: A comparative transcriptomic analysis was performed to identify regulatory pathways that develop before chilling injury symptoms are detectable using next generation sequencing on the fruits of two contrasting cultivars, one peach (Sagittaria) and one nectarine, (Big Top), over 14 days of postharvest cold storage. Results: There was a progressive increase in the number of differentially expressed genes between time points (DEGs) in both cultivars. More (1264) time point DEGs were identified in 'Big Top' compared to 'Sagittaria' (746 DEGs). Both cultivars showed a downregulation of pathways related to photosynthesis, and an upregulation of pathways related to amino sugars, nucleotide sugar metabolism and plant hormone signal transduction with ethylene pathways being most affected. Expression patterns of ethylene related genes (including biosynthesis, signaling and ERF transcription factors) correlated with genes involved in cell wall modification, membrane composition, pathogen and stress response, which are all involved later during storage in development of chilling injury. Discussion: Overall, the results show that common pathways are activated in the fruit of 'Big Top' nectarine and 'Sagittaria' peach in response to cold storage but include also differences that are cultivar-specific responses.

Metabolic changes induced by Cuscuta campestris Yunck in the host species Artemisia campestris subsp. variabilis (Ten.) Greuter as a strategy for successful parasitisation.

MAIN CONCLUSIONS: C. campestris parasitisation increases internal host defences at the expense of environmentally directed ones in the host species A. campestris, thus limiting plant defence against progressive parasitisation. Cuscuta campestris Yunck is a holoparasitic species that parasitises wild species and crops. Among their hosts, Artemisia campestris subsp. variabilis (Ten.) Greuter is significantly affected in natural ecosystems. Limited information is available on the host recognition mechanism and there are no data on the interactions between these species and the effects on the primary and specialised metabolism in response to parasitisation. The research aims at evaluating the effect of host-parasite interactions, through a GC-MS untargeted metabolomic analysis, chlorophyll a fluorescence, ionomic and δ13C measurements, as well as volatile organic compound (VOC) fingerprint in A. campestris leaves collected in natural environment. C. campestris parasitisation altered plant water status, forcing stomatal opening, stimulating plant transpiration, and inducing physical damages to the host antenna complex, thus reducing the efficiency of its photosynthetic machinery. Untargeted-metabolomics analysis highlighted that the parasitisation significantly perturbed the amino acids and sugar metabolism, inducing an increase in the production of osmoprotectants, which generally accumulate in plants as a protective strategy against oxidative stress. Notably, VOCs analysis highlighted a reduction in sesquiterpenoids and an increase in monoterpenoids levels; involved in plant defence and host recognition, respectively. Moreover, C. campestris induced in the host a reduction in 3-hexenyl-acetate, a metabolite with known repellent activity against Cuscuta spp. We offer evidences that C. campestris parasitisation increases internal host defences via primary metabolites at the expense of more effective defensive compounds (secondary metabolites), thus limiting A. campestris defence against progressive parasitisation.