Mache Research Articles

From Asbestos: The Story of a Tuscan Welder

from Asbestos: The Story of a Tuscan Welder Alberto Prunetti (bio) Translated by Oonagh Stransky (bio) I carry an image of him wearing green coveralls and a pair of chamois gloves. He kneels down on the gravel at the construction site with the angle grinder in front of him. He picks up his mallet and screwdriver, strikes the well-worn handle of the screwdriver to loosen the ring that holds the wire wheel in the grinder, and inserts a cutting wheel. He flicks the switch on with his gloved thumb. The blade spins at the speed of ten thousand rotations per minute. He brings the disc up to the gray pipe. When they come into contact, there’s a metallic scream, followed by an explosion of sparks and a dry eruption of regularly shaped fibrous particles. Small crystalline darts. Invisible shards that find their way into the esophagus or lungs, that stick to the pleura for twenty, thirty, even forty years, and that cause a wound that the body can’t heal or eradicate, triggering a process of cellular degeneration. A tumor. He stretches an industrial extension cord around the perimeter of a storage tank filled with hydrocarbons. The ground is viscous with slimy oil, black veering towards cobalt. He connects the welding machine to the cord, attaches the clamp to a metal component, inserts an electrode to a second clamp, and then places it on the ground. With his left hand, he picks up a welder’s mask and holds it to his face. Another worker grabs a dirty gray blanket and unfolds it over him, leaving him completely in the dark. With his right hand, he grabs the clamp and brings the electrode to the metal. A violent burst of light, attenuated by the tinted lens of the mask, bursts out: sparks fly off the tip of the quickly disappearing electrode, melting and lumping metal on metal. When the electrode is completely consumed, the man under the cloth grabs the mallet and, in total darkness, infers where the clump of now solid—but still incandescent—metal is located. He strikes the clot with the mallet and breaks apart the crust of slag. Welding only a few inches away from a fuel tank is dangerous. A single spark could trigger an explosion that could blow up an entire refinery. That’s why they tell him to use that dirty gray blanket. It’s heat resistant since it’s made from a lightweight, indestructible material: asbestos. Under the blanket, it’s just him and the sparks and the substances that are freed up by the fusion of the electrode. Just one single fiber of asbestos, and twenty-six years later, he will be dead. [End Page 29] ________ This is the story of a man who has the same surname as me and the same birthday as me, but he’s not me. This is a story that begins with a pop song by Nada and ends with the toxic science of heavy metals. It’s 1969, the Swinging Sixties are coming to an end, and we’re at the Cardellino nightclub in Castiglioncello, near Livorno. Nada Malanima, a singer fresh off the Sanremo musical festival circuit, has become popular for her tune “Ma che freddo fa.” A member of the paparazzi from Livorno, locally known as “Nick Flash” for the blinding halogen light on his camera, takes a picture of her surrounded by waiters and fans. Standing next to her is a tall, thin man who vaguely resembles Jean-Paul Belmondo. Nada is just sixteen, and he’s twenty-four. His name is Renato, and he’s the main character of this story, which begins with an iconic song from the sixties and ends with his slow death. If this were a noir, the name of the killer would be revealed outright, but in this case, it’s a “workplace homicide.” The culprit is surrounded by evidence and by witnesses who deny any and all responsibility. There’s no happy ending and no resolution. The threat is still out there: a silent killer protected by an army of doctors, engineers, consultants, and businessmen. I’m reluctant to begin telling...

Characterization of spoilage‐related volatile organic compounds in packaged leaf salads

AbstractA study has been made of the volatile organic compounds (VOCs) released into the contained headspace of packaged lamb's lettuce (Valerianella locusta) plants, cut at the roots, and of separated rocket (Eruca sativa) and baby spinach (Spinacia oleracea) leaves. Direct real‐time analyses of the headspace were carried out on each of five consecutive days using selected‐ion flow‐tube mass spectrometry (SIFT‐MS) and secondary electrospray ionization mass spectrometry (SESI‐MS), together with concomitant off‐line analyses using solid‐phase microextraction (SPME) and gas chromatography mass spectrometry (GC‐MS). It was observed that the concentrations of organosulphur compounds, especially dimethyl sulphide (DMS) and dimethyl disulphide (DMDS) were relatively low in the headspace of fresh samples, but increased exponentially over the 5 days for rocket, increased to a lesser extent for spinach, and increased to an even lesser extent for lamb's lettuce. Methanol was detected in the headspace of even fresh samples of lamb's lettuce, and its concentration increased for the subsequent 2–3 days before decreasing. This trend was mirrored in the isoprenoids analysed, which are characteristic of plant tissues. These results show that direct real‐time VOC analyses by SIFT‐MS can be usefully exploited to monitor fresh leaf salad spoilage, and that SESI‐MS spectra show patterns that are characteristic of salad type and storage time.

Plant variety and soil type influence Escherichia coli O104:H4 strain C227/11ϕcu adherence to and internalization into the roots of lettuce plants

Human disease outbreaks caused by pathogenic Escherichia coli are increasingly associated with the consumption of contaminated fresh produce. Internalization of enteroaggregative/enterohemorrhagic E. coli (EAEC/EHEC) strains into plant tissues may present a serious threat to public health. In the current study, the ability of the fluorescing Shiga toxin-negative E. coli O104:H4 strain C227/11ϕcu/pKEC2 to adhere to and to internalize into the roots of Lactuca sativa and Valerianella locusta grown in diluvial sand (DS) and alluvial loam (AL) was investigated. In parallel, the soil microbiota was analyzed by partial 16S rRNA gene sequencing. The experiments were performed in a safety level 3 greenhouse to simulate agricultural practice. The adherence of C227/11ϕcu/pKEC2 to the roots of both plant varieties was increased by at least a factor three after incubation in DS compared to AL. Compared to V. locusta, internalization into the roots of L. sativa was increased 12-fold in DS and 108-fold in AL. This demonstrates that the plant variety had an impact on the internalization ability, whereas for a given plant variety the soil type also affected bacterial internalization. In addition, microbiota analysis detected the inoculated strain and showed large differences in the bacterial composition between the soil types.

Impact of cooling temperature and wrapping on storage quality of lamb’s lettuce (Valerianella locusta L.)

Impact of cooling temperature and wrapping on storage quality of lamb’s lettuce (<i>Valerianella locusta</i> L.)

Salmonella Establishment in Agricultural Soil and Colonization of Crop Plants Depend on Soil Type and Plant Species.

Human pathogenic bacteria, such as Salmonella enterica, are able to colonize crop plants. So far, not much is known about biotic and abiotic factors influencing this colonization in field soil. This understanding, however, is imperative for the provision of safe fresh produce to the consumer. In this study, we investigated the effects of soil type, organic fertilization, plant species and the way of Salmonella entry into the plant production system, on the survival of S. enterica in soil as well as the colonization of plants. The selected S. enterica serovar Typhimurium strain 14028s, S. Typhimurium strain LT2 and S. Senftenberg were able to persist in soil for several weeks. Salmonella’s persistence in soil was prolonged in loamy, if compared to sandy soil, and when applied together with organic fertilizer. The leaves of lettuce and corn salad were colonized by S. enterica providing evidence for internalization from the soil via the root. Colonization rates were affected by soil type, plant species and S. enterica strain. Overall, S. enterica was detected in leaves of 0.5–0.9% of the plants, while lettuce was more frequently colonized than corn salad. Plants grown in sandy soil were more often colonized than plants grown in loamy soil. After spray inoculation, S. enterica could be detected on and in leaves for several weeks by cultivation-depending methods, confirmed by confocal microscopy using GFP-labeled S. Typhimurium 14028s. On the one hand, transcriptome data from S. Typhimurium 14028s assessed in response to lettuce medium or lettuce root exudates showed an upregulation of genes associated with biofilm formation and virulence. On the other hand, lettuce inoculated with S. Typhimurium 14028s showed a strong upregulation of genes associated with plant immune response and genes related to stress response. In summary, these results showed that organic fertilizers can increase the persistence of Salmonella in soil and that soil type and plant species play a crucial role in the interactions between human pathogens and crop plants. This understanding is therefore a starting point for new strategies to provide safe food for the consumer.

Root uptake of atenolol, sulfamethoxazole and carbamazepine, and their transformation in three soils and four plants.

Soils can be contaminated by pharmaceuticals. The aim of this study was to evaluate the impact of soil conditions (influencing sorption and persistence of pharmaceuticals in soils) and plant type on the root uptake of selected pharmaceuticals and their transformation in plant-soil systems. Four plants (lamb's lettuce, spinach, arugula, radish) planted in 3 soils were irrigated for 20days (26) with water contaminated by one of 3 pharmaceuticals (carbamazepine, atenolol, sulfamethoxazole) or their mixture. The concentrations of pharmaceuticals and their metabolites in soils and plant tissues were evaluated after the harvest. Sulfamethoxazole and atenolol dissipated rapidly from soils. The larger concentrations of both compounds and an atenolol metabolite were found in roots than in leaves. Sulfamethoxazole metabolites were below the limits of quantifications. Carbamazepine was stable in soils, easily uptaken, accumulated, and metabolized in plant leaves. The efficiency of radish and arugula (both family Brassicaceae) in metabolizing was very low contrary to the high and moderate efficiencies of lamb's lettuce and spinach, respectively. Compounds' transformations mostly masked the soil impact on their accumulation in plant tissues. The negative relationships were found between the carbamazepine sorption coefficients and its concentrations in roots of radish, lamb's lettuce, and spinach.

Growth potential of Listeria monocytogenes in twelve different types of RTE salads: Impact of food matrix, storage temperature and storage time

Listeriosis is a food borne disease associated with high hospitalization and fatality rates; in 2014, EU member states reported 2194 cases with 98.9% hospitalization rates and 210 fatalities. Proper risk analysis and the development of effective food safety strategies critically depend on the knowledge of the growth characteristics of L. monocytogenes on the product in question. Ready-to-eat (RTE) salads present a challenge in this context due to the absence of a heat treatment step before consumption. This study provides challenge-test based data of the growth characteristics of L. monocytogenes on twelve RTE salads. The food matrix, storage time and storage temperature were factors with a significant impact on the growth of L. monocytogenes. While most tested salads permitted a significant increase of L. monocytogenes in at least one of the tested conditions, no growth was observed on celeriac, carrot and corn salad products. There was a considerable increase in growth at 8 °C compared to 5 °C. Our data indicate that the reduction of the storage temperature at retail level to 5 °C and product shelf life could help mitigate the risk of L. monocytogenes in RTE salads.

Accumulation of Mineral Nutrients and Phytochemicals in Lettuce and Tomato Grown in High Tunnel and Open Field

High tunnel production of horticultural food crops is becoming increasingly popular and has a significant impact on their growth, productivity and nutritional quality. The present study examines the effect of high tunnel production of lettuce (Lactuca sativa cv. “Two Star” and “New Red Fire”) and tomato (Solanum lycopersicum cv. “Celebrity” and “Mountain Fresh”) on their nutritional quality relating to major nutrients and health-promoting phytochemicals. High tunnel environment increased the concentration of N (protein) in both lettuce and tomato relative to the open field cultivation. The accumulation pattern of mineral nutrients in high tunnel was similar in green-leaf and red-leaf lettuce varieties. Lettuce varieties grown in high tunnel had higher accumulation of C, S and Zn relative to those grown in open field. However, high tunnel environment suppressed the accumulation of many micronutrients such as Mg, Fe, Cu and Mn in both lettuce varieties but not in tomato. For example, accumulation of Fe was reduced by more than 80% in “Two Star” and by more than 55% in “New Red Fire” under high tunnel. It also suppressed the levels of many health-promoting phenolic compounds such as chlorogenic acid, chicoric acid, rutin and kaempferol in green-leaf lettuce and gallic acid in red-leaf lettuce. High tunnel environment improved the soil nutrient status but reduced the radiation levels (PAR, UV-A and UV-B) received by the crops. The results show that the high tunnel production has a significant impact on the nutritional quality relating to protein and mineral nutrients in both crops and health-promoting phytochemicals in lettuce.

Riguardando Giovanni Boccaccio: Narrative Distraction as Self-Care in Franco Sacchetti's Trecentonovelle

Riguardando Giovanni Boccaccio:Narrative Distraction as Self-Care in Franco Sacchetti's Trecentonovelle Martin Marafioti (bio) With his Trecentonovelle, Franco Sacchetti created a narrative outlet for his readers by proposing a series of entertaining, clever and, at times, moralistic stories to act as distraction from the woes facing late-fourteenth-century Florentine society. It is believed that Sacchetti began composing his novelle shortly after Giovanni Boccaccio's death and continued to re-elaborate them until his own death in 1400. It is evident that Sacchetti was inspired by Boccaccio's Decameron, and in some ways sought to emulate the form and structure of the work of his literary master. But the Trecentonovelle was not simply an exercise in stylistic imitatio. Sacchetti's personal biography suggests that hardship, trauma and illness motivated the composition of the author's individual stories and the gathering of these stories in a structural framework à la Boccaccio.1 During his lifetime, Sacchetti had developed a solid reputation as a writer and was known for his encomiastic poem La battaglia delle belle donne di Firenze (1352), his songbook Libro delle Rime (1336-1400) and his highly personal reflections on the gospels Sposizioni ai Vangeli (1392-1381). His most widely read work, however, was (and is still) the Trecentonovelle, completed between 1392 and 1400.2 In his final years, [End Page S-184] Sacchetti faced a series of distressing events, including the War of the Eight Saints, the Ciompi revolt and the Florentine war against Gian Galeazzo Visconti of Milan, as well as several personal hardships: the deaths of his first wife, second wife and son from unspecified illnesses; the execution of his brother Giannozzo; the loss of a large part of his fortune to pirates while travelling from Genova to Pisa; the arson of his family estate in Marignolle; and his own serious personal health problems.3 These were also the years of the ever present menace that altered the fates not only of Sacchetti but also of many of his associates: the epidemics of pestilence and smallpox that decimated the city of Florence throughout the late fourteenth century.4 These biographical data are useful for understanding Sacchetti's frame of mind while composing his stories. Lanfranco Caretti reminds us that it is important to consider Sacchetti's hardships when reading the novelle: "[p]roprio per questo, essendo nato in fondo dalla [End Page S-185] tristezza e al tramonto di una vita guerreggiata, il Trecentonovelle non può essere semplicemente interpretato come la rappresentazione spassionata e scherzosa di una realtà spensieratamente accolta."5 The author's despairing, world-weary outlook is also prevalent in many of the poems in Sacchetti's Libro delle rime that focus on disastrous events, such as military battles (poems 102, 112 and 207), deaths (181 on the death of Boccaccio and 248 on the death of Sacchetti's brother) and epidemics (51, 65, 169 and 170). One of the most testimonial poems of his collection is the Frottola di Franco sopra le nuove disposizioni del mondo mutate al male, which mirrors Sacchetti's attitudes towards a world that he feels has little hope: O mondoimmondoe di ben mondo,che già fosti giocondoed ora al fondovai di male in peggio!6 These lines represent an emotional and charged tirade against what Sacchetti views as the "evils" of his society. He denounces corruption in the church, a fraudulent political system and, more generally, a society lacking scruples and specifies the downfall of particular groups such as merchants and professionals. Sacchetti strongly condemns the insatiable greed he felt was becoming so rampant in his society ("ma che tristizia de le monete!") and in this composition, offers no optimism. This prominent fatalistic vein runs throughout the rhyme book and travels with Sacchetti to the beginning of his Trecentonovelle. Like Boccaccio, Sacchetti starts his collection of stories with a proem in which he addresses his audience, describing turn-of-the-century Florence as grievous and bleak: Considerando al presente tempo e alla condizione dell'umana vita, la quale con pestilenziose infirmità e con oscure morti è spesso vicitata; e veggendo quante rovine con quante guerre civili e campestre in essa dimorano; e pensando quanti...

Baldassarre Castiglione diplomatico: la missione del cortegiano by Raffaele Ruggiero

 Reviews treatment in epic in Italy and offers valuable and interesting perspectives on the different interpretations of this stream of literature across the centuries. L T C B Baldassarre Castiglione diplomatico: la missione del cortegiano. By R R- . (Biblioteca dell’Archivum Romanicum, Serie , Storia, letteratura, paleografia, ) Florence: Olschki. . xv+ pp. €. ISBN –– ––. In  two important works dedicated to Baldassarre Castiglione were published: the complete edition of his family and diplomatic letters (Lettere famigliari e diplomatiche , ed. by Guido La Rocca, Angelo Stella, and Umberto Morando; Lettera ad Alfonso Valdés, ed. by Paolo Pintacuda, with notes by Roberto Vetrugno and a note on the illustrations by Luca Bianco,  vols (Turin: Einaudi, )), and the three-volume edition of Il libro del Cortegiano, edited by Amedeo Quondam (Rome: Bulzoni, ), which contains the editio princeps (vol. ), the text of the manuscript Ashburnhamiano  preserved in the Biblioteca Medicea Laurenziana in Florence (vol. ), and a description of the evolution of the dialogue from manuscript to printed book (vol. ). ese works offer a solid basis for this monograph by Raffaele Ruggiero, who aims to read Il Cortegiano through the lens of the diplomatic experience of his author. rough a close reading of the letters sent to Castiglione’s relatives, friends, patrons, and colleagues, Ruggiero reviews the role that Castiglione played on the European political scene, from his first journey to England in , on behalf of the Duke of Urbino Guidubaldo da Montefeltro, to his last mission as papal nuncio in Spain, between  and . e analysis of Castiglione’s diplomatic career results in a detailed history of Italian (and European) politics in the first thirty years of the sixteenth century. In some cases, the reconstruction of the broader framework seems more relevant than Castiglione’s personal contribution, as shown by the chapter dedicated to the Medici papacy (pp. –). However, this solid background—though with some minor redundancies (as in the descriptions of Pope Adrian VI at pp.  and )—is never an end in itself; rather, it is meant to support a critical interpretation of the choices made by Castiglione. e attention paid to the politics of Leo X, for example, is designed to explain Castiglione’s passage from Urbino to Rome: ‘una transizione che non è solo legata a scelte opportunistiche e personali, ma che si sposa con una esatta valutazione sul tramonto delle piccole signorie italiane e sull’esigenza di una voce autorevole (quella dello stato ecclesiastico) per tenere l’Italia almeno su un piano paritario rispetto alle potenze europee’ (p. ). e acknowledgement of the weakness of Italian courts and the need for a different involvement of Italy on the international scene has a direct impact on the functions of the intellectuals, gradually transformed from courtiers into secretaries. is is an aspect which, according to Ruggiero, deeply influences the evolution of Il Cortegiano and, particularly, the writing of its fourth and final book. MLR, .,   In the first part of Castiglione’s diplomatic career, one addressee in particular stands out from his letters: namely, his mother Aloisia Gonzaga, who appears as a ‘donna esperta e attenta alle evoluzioni della politica italiana ed europea’ and a ‘consigliera prudente’ (p. ). e interest in contemporary political matters shown by Aloisia is noticeable, not only for the pieces of advice that she gives to her son, but also for the influence that her model might have had on the way Castiglione represents women and addresses the querelle des femmes in the third book of Il Cortegiano. is is not the only connection between his correspondence and the dialogue. In fact, his letters frequently anticipate or mirror topics that have an absolute relevance in the text, such as the influence of fortuna on human lives (p. ), ‘l’attenzione [. . .] prestata agli aspetti cerimoniali’ (p. ), and, above all, the interest in a regulated use of language(s) (p. ). Trained in the (humanistic and diplomatic) art of perfect communication, Castiglione identifies in an effective conversation the main goal of an ideal courtier. is is, as stated in the subtitle of the book by Ruggiero, the ‘mission’ of Il Cortegiano, a text that can thus stand as ‘il lessico della classe dirigente europea’ (p. ), even aer the...

Modification of the existing maximum residue levels and setting of import tolerances for pyraclostrobin in various crops.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant BASF SE submitted two requests to the competent national authority in Germany. The first one, to modify the existing maximum residue levels (MRL) for the active substance pyraclostrobin in various crops and to set import tolerances for sugar canes and American persimmons; the second one to set import tolerances for pineapples and passion fruits/maracujas. The data submitted in support of the requests were found to be sufficient to derive MRL proposals for mandarins, grapefruits, lemons, limes, passion fruits/maracujas, pineapples, flowering brassica, head cabbages, lamb's lettuce, cresses and other sprouts, land cresses, rucola, red mustards, baby leaf crops, globe artichokes and leeks. For oranges, American persimmons, spinaches and similar leaves and sugar canes, data gaps were identified which precluded the derivation of MRL proposals. The data submitted did not provide evidence that the existing MRLs for crops belonging to the group of lettuces and maize have to be modified to accommodate for the intended uses. For escaroles, no MRL was proposed as the intended use was found to lead to residues for which a potential consumer health risk cannot be excluded. EFSA concluded that the short‐term intake of residues resulting from the uses of pyraclostrobin according to the reported agricultural practices assessed is unlikely to present a risk to consumer health, except for escaroles, where the expected intake was found to exceed the toxicological reference value. Taking into account the existing and the proposed new MRLs, a long‐term intake concern for consumers was not identified.

Eye-tracking analysis of leafy vegetables

There is a great supply of leafy vegetables on the market; hence capturing consumer’s attention (and decision) is critically important. Several scientific publications deal with consumer choices and the newest technology to capture consumer attention is eye-tracking. Eye-trackers are commonly used in Western Europe and Asia also, where it is an important and widely-used tool during product developments and the creation of marketing strategies. In Hungary, there are only a few publications about eye-tracking applications in vegetable growing and food industry. In our research, photographs about sorrel, lamb lettuce, spinach, leaf lettuce and dandelion leafs were analysed by eye-tracking technology and the eye movements of the participants during their decision making process of leafy vegetables were captured and evaluated. The eye-tracking analyses were carried out in the Sensory Laboratory of the Faculty of Food Sciences of Szent István University, using a Tobii X2-60 eye-tracker and Tobii Studio (version 3.0.5, Tobii Technology AB, Sweden) software. We aimed to answer the following research questions: Are there any connections between the eye movements of participants and their decisions? What amount of visual attention can be registered during the decision making process? Furthermore, the following metrics were measured and evaluated: fixation durations on the leafy vegetables, number of returns to products, pathways of visual attention, time until the final decision making and motivation of their final decisions. Measurement of the subconscious consumer decision making processes is way easier using eye-trackers compared to the traditional questionnaire-based methods, because it is hard or impossible to control our eye movements. Eye-tracking can be used successfully for understanding the expectations and decisions of the consumers.

Effect of Plug Cell Size on Growth and Yield of Corn Salad Transplants

Effect of Plug Cell Size on Growth and Yield of Corn Salad Transplants

Biological and Genetic Characterization of New and Known Necroviruses Causing an Emerging Systemic Necrosis Disease of Corn Salad (Valerianella locusta) in France.

An emerging systemic necrosis disease of corn salad was first observed in the Nantes region of France in the late 2000s. Classical virology and high-throughput sequencing approaches demonstrated that the disease is associated with four different necroviruses: tobacco necrosis virus A (TNVA), tobacco necrosis virus D (TNVD), olive mild mosaic virus (OMMV), and a novel recombinant Alphanecrovirus for which the name corn salad necrosis virus (CSNV) is proposed. Satellite tobacco necrosis virus was also frequently observed. Koch's postulates were completed for all four agents, each one alone being able to cause systemic necrosis of varying severity in corn salad. OMMV was the most frequently observed virus and causes the most severe symptoms. TNVA was the second, both in terms of prevalence and symptom severity while TNVD and CSNV were only rarely observed and caused the less severe symptoms. The emergence of this systemic disease may have been favored by the short and repeated cropping cycles used for corn salad, possibly allowing the selection of necrovirus isolates with an improved ability to systemically invade this specialty crop.

Peer review of the pesticide risk assessment of the active substance Bacillus subtilis strain IAB/BS03.

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State the Netherlands, for the pesticide active substance Bacillus subtilis strain IAB/BS03 are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative uses of B. subtilis strain IAB/BS03 as a fungicide on field lettuce, orchards and protected cucurbits. The reliable endpoints appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Adherence factors of enterohemorrhagic Escherichia coli O157:H7 strain Sakai influence its uptake into the roots of Valerianella locusta grown in soil

Increasing numbers of outbreaks caused by enterohemorrhagic Escherichia coli (EHEC) are associated with the consumption of contaminated fresh produce. The contamination of the plants may occur directly on the field via irrigation water, surface water, manure or fecal contamination. Suggesting a low infectious dose of 10 to 102 cells, internalization of EHEC into plant tissue presents a serious public health threat. Therefore, the ability of EHEC O157:H7 strain Sakai to adhere to and internalize into root tissues of the lamb's lettuce Valerianella locusta was investigated under the environmental conditions of a greenhouse. Moreover, the influence of the two adherence and colonization associated genes hcpA and iha was surveyed regarding their role for attachment and invasion. Upon soil contamination, the number of root-internalized cells of EHEC O157:H7 strain Sakai exceeded 102 cfu/g roots. Deletion of one or both of the adherence factor genes did not alter the overall attachment of EHEC O157:H7 strain Sakai to the roots, but significantly reduced the numbers of internalized bacteria by a factor of between 10 and 30, indicating their importance for invasion of EHEC O157:H7 strain Sakai into plant roots. This study identified intrinsic bacterial factors that play a crucial role during the internalization of EHEC O157:H7 strain Sakai into the roots of Valerianella locusta grown under the growth conditions in a greenhouse.

Emerging pathogens as a consequence of globalization and climate change: leafy vegetables as a case study.

In the recent years (2010–2016), leafy vegetables have been found to be hosts for many new diseases. The causal agents of these diseases had often been known on other crops, but have appeared for the first time throughout the world on several cultivated vegetable hosts such as: Lactuca sativa , Diplotaxis spp., Eruca sativa , Valerianella olitoria , Ocimum basilicum and Spinacia oleracea . This review considers pathogens such as Alternaria spp. on basil and rocket, Fusarium equiseti on lettuce, rocket and radish, and Myrothecium verrucaria and M. roridum on lamb’s lettuce, spinach and wild rocket. All these pathogens are seed-transmitted, a biological characteristic that raises the risk of worldwide dissemination. The role of climate change and globalization on the appearance of such diseases, and potential tools for their management under a climate change scenario, is discussed using leafy vegetables as a case study.

Selenium biofortification enhances the growth and alters the physiological response of lamb's lettuce grown under high temperature stress

We examined the possibility to enhance the growth and the physiological tolerance of lamb's lettuce (Valerianella locusta L.) grown under heat stress (HS) by biofortification with selenium (Se). The plants were grown at optimal (22/19 °C; day/night) or high (35/22 °C; day/night) temperature and Se was applied via foliar or soil treatment. The HS reduced plant biomass and photosynthetic pigment concentration and impaired some parameters of chlorophyll a fluorescence. The lamb's lettuce grown under HS accumulated large amounts of H2O2 in the leaves, especially in younger ones. The Se fertilization (both foliar and soil) at HS was beneficial to plant growth, whilst the concentration of photosynthetic pigments and the analysed parameters of chlorophyll a fluorescence were unaffected by the Se supply. The application of Se enhanced the thermo-tolerance of plants through cooperative action of antioxidant enzymes, such as guaiacol peroxidase (GPOX; EC 1.11.1.7) and catalase (CAT; EC 1.11.1.6), and reduced glutathione (GSH) among low-molecular-weight non-enzymatic antioxidants, in removal of excess of H2O2. Although under HS the content of different phenolic compounds in the leaves was higher than under normal temperature (NT), the application of Se did not affect their concentration at stress conditions. On the other hand, at NT the Se-biofortified plants accumulated significantly more phenolic compounds with health-promoting properties than Se-untreated plants. Therefore, biofortification of lamb's lettuce with Se can be beneficial in terms of plants yield and their nutritional value under both NT and HS.

The effect of sugar starvation on the metabolic response of isolated lamb’s lettuce (Valerianella locustaL.) cells

Leafy vegetables are highly perishable as they are exposed to carbohydrate starvation during their postharvest storage life, leading to premature quality loss. An in-depth knowledge of the fundamental metabolic regulation and control mechanisms of these leafy vegetables to sugar starvation is beneficial in understanding how they modify their metabolism to survive in the absence of sugar. To this purpose, isolated lamb's lettuce cells were incubated in the dark to trigger sugar starvation at different temperatures (25, 18 and 1°C) to monitor the dynamic changes in the metabolome over time. To understand which pathways were up- or down-regulated, the isolated cells were preloaded with uniformly labelled 13C glucose and the distribution of the 13C label throughout the different metabolic pathways was monitored. The higher the temperature, moving from 1 to 25°C, the faster the effect of sugar starvation was induced.

Emerging foliar and soil‐borne pathogens of leafy vegetable crops: a possible threat to Europe

Italy is one of the leading countries for the production and consumption of ready‐to‐eat salads. This has led to a steady increase in the area used over the last decade for the growth of leafy vegetables under intensive systems. The recent new diseases that affect lettuce, wild and cultivated rocket, lamb's lettuce, spinach and basil are reported here: Plectosphaerella cucumerina on wild rocket, endive and lamb's lettuce, Fusarium equiseti on wild and cultivated rocket and lettuce, Myrothecium verrucaria on spinach and wild rocket, Myrothecium roridum on lamb's lettuce, Allophoma tropica on lettuce and Alternaria sp. on basil and rocket are among the new foliar pathogens in Italy. Among the soil‐borne pathogens, Pythium aphanidermatum, Pythium irregulare and Pythium Cluster B2a have recently been isolated in Italy on spinach and Swiss chard, lamb's lettuce and lettuce, while Fusarium oxysporum f. sp. lactucae, which causes lettuce wilt, is gradually spreading to new countries. Some of the new pathogens have been found to be transmitted by seed and typical of tropical climate, and are thus favoured by the increases in temperature linked to climate change. The globalization of markets, climate change and intensive cultivation are among the factors responsible for the proliferation and spread of some of these new pathogens that are ‘alien’ to Italian production systems.