Tapping into the maize root microbiome to identify bacteria that promote growth under chilling conditions

Background When maize (Zea mays L.) is grown in the Northern hemisphere, its development is heavily arrested by chilling temperatures, especially at the juvenile phase. As some endophytes are beneficial for plants under stress conditions, we analyzed the impact of chilling temperatures on the root microbiome and examined whether microbiome-based analysis might help to identify bacterial strains that could promote growth under these temperatures. Results We investigated how the maize root microbiome composition changed by means of 16S rRNA gene amplicon sequencing when maize was grown at chilling temperatures in comparison to ambient temperatures by repeatedly cultivating maize in field soil. We identified 12 abundant and enriched bacterial families that colonize maize roots, consisting of bacteria recruited from the soil, whereas seed-derived endophytes were lowly represented. Chilling temperatures modified the root microbiome composition only slightly, but significantly. An enrichment of several chilling-responsive families was detected, of which the Comamonadaceae and the Pseudomonadaceae were the most abundant in the root endosphere of maize grown under chilling conditions, whereas only three were strongly depleted, among which the Streptomycetaceae. Additionally, a collection of bacterial strains isolated from maize roots was established and a selection was screened for growth-promoting effects on juvenile maize grown under chilling temperatures. Two promising strains that promoted maize growth under chilling conditions were identified that belonged to the root endophytic bacterial families, from which the relative abundance remained unchanged by variations in the growth temperature. Conclusions Our analyses indicate that chilling temperatures affect the bacterial community composition within the maize root endosphere. We further identified two bacterial strains that boost maize growth under chilling conditions. Their identity revealed that analyzing the chilling-responsive families did not help for their identification. As both strains belong to root endosphere enriched families, visualizing and comparing the bacterial diversity in these communities might still help to identify new PGPR strains. Additionally, a strain does not necessarely need to belong to a high abundant family in the root endosphere to provoke a growth-promoting effect in chilling conditions

Assessment of Five Chilling Tolerance Traits and GWAS Mapping in Rice Using the USDA Mini-Core Collection

Rice (Oryza sativa L.) is often exposed to cool temperatures during spring planting in temperate climates. A better understanding of genetic pathways regulating chilling tolerance will enable breeders to develop varieties with improved tolerance during germination and young seedling stages. To dissect chilling tolerance, five assays were developed; one assay for the germination stage, one assay for the germination and seedling stage, and three for the seedling stage. Based on these assays, five chilling tolerance indices were calculated and assessed using 202 O. sativa accessions from the Rice Mini-Core (RMC) collection. Significant differences between RMC accessions made the five indices suitable for genome-wide association study (GWAS) based quantitative trait loci (QTL) mapping. For young seedling stage indices, japonica and indica subspecies clustered into chilling tolerant and chilling sensitive accessions, respectively, while both subspecies had similar low temperature germinability distributions. Indica subspecies were shown to have chilling acclimation potential. GWAS mapping uncovered 48 QTL at 39 chromosome regions distributed across all 12 rice chromosomes. Interestingly, there was no overlap between the germination and seedling stage QTL. Also, 18 QTL and 32 QTL were in regions discovered in previously reported bi-parental and GWAS based QTL mapping studies, respectively. Two novel low temperature seedling survivability (LTSS)–QTL, qLTSS3-4 and qLTSS4-1, were not in a previously reported QTL region. QTL with strong effect alleles identified in this study will be useful for marker assisted breeding efforts to improve chilling tolerance in rice cultivars and enhance gene discovery for chilling tolerance

The chilling effect and the most ancient form of vengeance:discrimination and victimising third parties

The recent Equality Act 2010 includes a revised definition of “victimisation”, which (in the Act’s most litigated field of employment) prohibits employers from victimising workers who use the legislation. The underlying mischief should be the deterrent effect upon litigants, or potential litigants (the “chilling” effect). One particularly pernicious deterrent is the victimisation, not of the complainant, but of a third party, such as the complainant’s spouse, loved one, or friend, “the most ancient form of vengeance”. Yet the revised definition does not address the deterrent effect per se, and specifically excludes third party victimisation from its reach. This paper explores, first, why the deterrent mischief and the chilling effect should underpin the victimisation provision, so that it addresses third party victimisation, second, the potential of existing alternative solutions in domestic law; and third, the position EU law, and under the United States’ Civil Rights Act 1964. It concludes that the best existing solution lies in EU general principles, but for the sake of certainty, a simple amendment to the existing formula is required, which would solve the problem without any undue side-effects

Dynamic balancing of high-speed rotary machinery

Rotary dynamics test facility investigates and corrects imbalances in rotary components at speeds up to 60,000 rpm. Use of a vacuum chamber eliminates the effect of windage and facilitates the chilling of test pieces

Study Effect of Irradiation 0.75 Kgy Dose on Chilling Injury Symptoms of Mango CV Gedong During Stored

Low temperature storage may cause mango experience the chilling injury. Study on the chilling injury symptoms of mango stored under low temperature storage and effect on mango irradiated 0,75 kGy will be very important in order to understand better method to reduction of chilling injury. This research objective was to study the effect of irradiation gamma rays on the chilling injury symptopms of mango fruits stored at 8, 13°C and room temperature. The quality of mango during storage were evaluated from the changes in respiration rate, firmness, weight loss, total soluble solid, total acid and pH. The result showed that mango fruits experienced chilling injury at storage condition of 8°C. The chilling injury symptoms was showed by the mango of control. This phenomenon of chilling injury symptoms at 8°C was also indicated by quality parameter. The mango of irradiated can reduced of chilling injury symptoms

Indicator organisms to determine the use of chilling as a critical point in beef slaughter HACCP

End of project reportDuring chilling, temperatures of carcass surfaces at different sites change over time as do other parameters such as water activity (aw), the structure of the muscle and other tissues, as the carcass enters rigor mortis. Many of these factors are known to have a major effect on cell survival and growth and must be considered in determining the influence of chilling on bacterial survival on carcass surfaces. This study aimed to determine if chilling could be used as a critical control point (CCP) in beef slaughter in relation to pathogens such as E. coli O157:H7 and L. monocytogenes, using E. coli and Listeria innocua as pathogen indicators. The present study was designed to determine the influence of (a) chilling at 10oC for 72 h on the survival of E. coli and (b) chilling at 4oC for 72 h on the survival of L. innocua inoculated at different sites on beef carcasses. Three sites (neck, outside round and brisket) were inoculated (1) immediately after dressing while hot (E. coli and L. innocua) and (2) when cold after chilling (L. innocua). The influence of changes in surface aw was also considered and their relationship to the survival of E. coli and L. innocua over time was assessed. The data are discussed in relation to the use of chilling as a CCP in beef hazard analysis (HACCP) and the monitoring of neck temperature as the most suitable CCP.National Development Pla

Development of a mathematical model for 'Hayward' kiwifruit softening in the supply chain : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, New Zealand

Fruit loss is a major concern to the kiwifruit industry as it incurs a high cost to monitor and remove over soft or rotten fruit to meet export standards. Kiwifruit is exposed to various temperature scenarios due to different packhouse cooling practices, and temperature control is difficult to maintain throughout the supply chain. Fruit pallet temperatures are wirelessly monitored in the supply chain. This time temperature data provides valuable rich information which could be used to predict kiwifruit quality. In the laboratory, green ‘Hayward’ kiwifruit were exposed to industry coolchain scenarios to investigate their influence on fruit firmness in subsequent storage. Cooling rate and storage temperature were identified to affect fruit firmness and chilling injury development significantly, where accelerated softening and increased chilling injury development was observed in late storage (> 100 d) when fruit were cooled directly to 0 °C. However, when fast cooled fruit were stored at 2 °C instead of 0 °C, low incidence of chilling injury was observed. The influence of cooling rate and storage temperature on kiwifruit quality suggests that industry should focus on the management practices adopted by packhouses in order to maintain acceptable quality after long term storage. A proportion of the firmness data results were used to develop a mechanistic style mathematical model of kiwifruit softening. Kiwifruit softening was mathematically described based on the correlation with starch degradation, breakdown of cell wall structure, and a description of the incidence of chilling injury development during storage. The model inputs consist of solely commonly collected at-harvest attributes: firmness, dry matter and soluble solids content and time-temperature data. Applying at-harvest attributes as model inputs enabled a capability to predict different softening curves as influenced by fruit maturity, and grower line differences. The developed model demonstrated promising softening prediction with mean absolute errors (MAE) between 0.8 to 2.1 N when fruit were exposed to fluctuating temperatures and cooling profiles. A logistic model was used to estimate the proportion of chilling injured fruit. Based on the given time temperature information, the logistic model was able to predict the proportion of chilling injured fruit reasonably well (R2 = 0.735). This chilling injury prediction was subsequently used to adjust the softening prediction during the late storage period (>100 d). Model validation was performed using the remaining data, identifying a lack of fit in both the rapid (MAE of 20.8 N) and gradual (MAE of 8.0 N) softening phase. The lack of fit in the rapid softening phase is proposed to be explained by the presence of an initial lag phase in softening which the developed model is unable to predict. The magnitude of firmness associated with starch content and cell wall integrity heavily influenced the lack of fit in the gradual softening phase. Fixing the initial amount of firmness associated to cell wall integrity to be constant for all maturities and grower lines improved the softening prediction. Overall, this thesis contributes to the challenge of predictively modelling kiwifruit quality in the supply chain. However, there are still many opportunities for improvement including introducing the influence of: variation within the same batch; fruit maturity on chilling injury development; ethylene in the environment; pre-harvest management practices and extending the model to have more focus on high temperature conditions such as those experienced in the marketplace. Conducting studies on: the effect of curing on kiwifruit; using non-destructive techniques to provide information to help define model parameters for prediction; effect of high temperature exposure on kiwifruit softening are possible opportunities that may contribute to enable better prediction of kiwifruit quality in the supply chain in the future

The fallout from the McAlpine saga threatens the role of Twitter in public life

The fallout from the McAlpine saga has led to increasing fears that legal action will have a ‘chilling effect’ on the microblogging platform. Paul Bernal argues that Twitter provides something quite special for the media and that it should be nurtured. It’s possible a defence may develop naturally from the legal processes McAlpine’s team bring about but, if not, we ought to work to develop it

The effect of traditional handling, processing and storage methods on the quality of dried fish in small scale fisheries in Nigeria

Most of the fish marketed throughout Nigeria are in either smoked or dried form. The technological requirement for other forms of preservation like chilling and freezing cannot be afforded by the small scale fisher folk. Considerable quantities of fish processed for distant consumer markets are lost at handling, processing, storage and marketing stages. Significant losses occur through infestation by mites, insects, fungal infestation and fragmentation during transportation. This paper attempts to describe the effect of these losses on fish quality and suggests methods of protecting fish from agents of deterioratio