The Potential of Self-Activating Au(I) Complexes in Gold Catalysis.

Gold catalysis has emerged as a groundbreaking field in synthetic chemistry, revolutionizing numerous organic transformations. Despite the significant achieved advancements, the mechanistic understanding behind many gold-catalyzed reactions remains elusive. This Concept article covers the so-called "self-activating" Au(I) complexes, sorting out their pivotal role in gold catalysis. We comment on how Au(I) complexes can undergo self-activation, triggering diverse catalytic transformations without the need for external additives. The most important examples reported so far that underlie the catalytic activity of these species are discussed. This intrinsic reactivity represents a paradigm shift in gold catalysis, offering new avenues for the design of efficient and sustainable catalytic systems. Furthermore, we explore the factors influencing the stability, reactivity, and selectivity of these Au(I) complexes, providing insights into their synthetic utility and potential applications in synthesis. This area of research not only advances our fundamental understanding of gold catalysis but also paves the way for the development of novel catalytic strategies with broad implications in organic synthesis and the chemical industry.

Ferrocenyl Dinuclear Gold(I) Complexes. Study of their Structural Features and the Influence of Bridging and Phosphane Ligands in a Catalytic Cyclization Reaction.

Invited for the cover of this issue are the groups of Raquel P. Herrera and M. Concepción Gimeno at the Instituto de Síntesis Química y Catálisis Homogénea (University of Zaragoza-CSIC). The image depicts the light of the full moon illuminating a bridge between the gold(I) metal centers. Two dragons, symbolizing the use of bridging ligands, confront each other to determine the ultimate victor. Read the full text of the article at 10.1002/chem.202303585.

Unlocking the catalytic potential of gold(II) complexes: a comprehensive reassessment.

Gold(II) complexes, unlike their gold(I) and gold(III) counterparts, have been sparsely employed in the field of catalysis. This is primarily due to the challenges associated with isolating and characterising these open-shell species. However, these complexes offer a wide range of possibilities. On one hand, this intermediate oxidation state has proven to be more easily accessible through reduction and oxidation processes compared to the gold(I)/gold(III) redox couple, thereby facilitating potential homo-coupling and cross-coupling reactions. On the other hand, gold(II) exhibits Lewis acid behaviour, bridging the characteristics of the soft acid gold(I) and the hard acid gold(III). In this review, we focus on mono- and dinuclear gold(II) complexes, whether they are isolated and well-studied or proposed as intermediates in cross-coupling reactions induced by the action of oxidants or light. We delve into the unique reactivity and potential applications of these gold(II) species, shedding light on their role in this field. This comprehensive exploration aims to underscore the latent promise of gold(II) complexes in catalysis, offering insights into their structural and mechanistic aspects while highlighting their relevance in contemporary chemical transformations.

Ferrocenyl Dinuclear Gold(I) Complexes. Study of their Structural Features and the Influence of Bridging and Phosphane Ligands in a Catalytic Cyclization Reaction.

The combination of the ferrocene moiety with gold(I) catalysis remains a relatively unexplored field. In this article, we delve into the synthesis, characterization, and potential catalytic activity of four complexes utilizing both monodentate and bidentate ferrocenyl diphenylphosphane ligands (ppf and dppf), coordinated with two gold(I) metal centers, linked by either chloride or pentafluorophenylthiolate bridging ligands. This leads to the formation of cationic "self-activated" precatalysts capable of initiating the catalytic cycle without the need for external additives. The catalytic activity of these complexes was assessed through a model reaction in gold(I) catalysis, specifically the cyclization of a N-propargylbenzamide to produce an oxazole. In addition, we studied and compared the influence exerted by both the phosphane and the bridging ligand on the performance of these catalysts.

Entomopathogenic Nematode Compatibility with Vineyard Fungicides.

Vineyards, covering over seven million hectares worldwide, hold significant socio-cultural importance. Traditionally reliant on conventional practices and agrochemicals, this agroecosystem faces environmental challenges, including soil and water pollution. Sustainable viticulture, driven by eco-friendly practices and cost reduction, has gained prominence, underlining the importance of biological control agents such as entomopathogenic nematodes (EPNs). EPNs naturally occurr in vineyard soils and play a crucial role in controlling pest damage. Ensuring compatibility between EPNs and the commonly used vineyard fungicides is critical, as these applications constitute the predominant pest-management practice during the productive grapevine cycle. This study assessed the impact of authorized grapevine fungicides on EPNs, focusing on the survival of populations and sublethal effects on their virulence. We investigated the compatibility of two EPN populations (Steinernema feltiae 107 and S. carpocapsae 'All') with three organic production-approved products (Bacillus pumilus, sulfur, and copper oxychloride) and two synthetic chemicals (Trifloxystrobin and Mancozeb). Our findings revealed that the viability of S. feltiae 107 was reduced when exposed to sulfur and copper oxychloride, and its virulence was affected by copper oxychloride and Mancozeb, although only two days after exposure and with no significant differences for larval mortality at five days. In contrast, S. carpocapsae 'All' exhibited full compatibility with all five fungicides, with no impact on its viability or virulence. Consequently, our results suggested that the evaluated fungicides could be co-applied on both EPN populations if they were employed on the same day. However, further research on multi-target interactions is needed to ensure the successful implementation of this kind of co-application.

Systematic characterization of a non-transgenic Aß1-42 amyloidosis model: synaptic plasticity and memory deficits in female and male mice.

BACKGROUND: The amyloid-ß (Aß) cascade is one of the most studied theories linked to AD. In multiple models, Aß accumulation and dyshomeostasis have shown a key role in AD onset, leading to excitatory/inhibitory imbalance, the impairments of synaptic plasticity and oscillatory activity, and memory deficits. Despite the higher prevalence of Alzheimer's disease (AD) in women compared to men, the possible sex difference is scarcely explored and the information from amyloidosis transgenic mice models is contradictory. Thus, given the lack of data regarding the early stages of amyloidosis in female mice, the aim of this study was to systematically characterize the effect of an intracerebroventricular (icv.) injection of Aß1-42 on hippocampal-dependent memory, and on associated activity-dependent synaptic plasticity in the hippocampal CA1-CA3 synapse, in both male and female mice. METHODS: To do so, we evaluated long term potentiation (LTP) with ex vivo electrophysiological recordings as well as encoding and retrieval of spatial (working, short- and long-term) and exploratory habituation memories using Barnes maze and object location, or open field habituation tasks, respectively. RESULTS: Aß1-42 administration impaired all forms of memory evaluated in this work, regardless of sex. This effect was displayed in a long-lasting manner (up to 17 days post-injection). LTP was inhibited at a postsynaptic level, both in males and females, and a long-term depression (LTD) was induced for the same prolonged period, which could underlie memory deficits. CONCLUSIONS: In conclusion, our results provide further evidence on the shifting of LTP/LTD threshold due to a single icv. Aß1-42 injection, which underly cognitive deficits in the early stages of AD. These long-lasting cognitive and functional alterations in males and females validate this model for the study of early amyloidosis in both sexes, thus offering a solid alternative to the inconsistence of amyloidosis transgenic mice models.

This study focuses on investigating how amyloid-ß (Aß), a key toxic protein in Alzheimer's disease (AD), impacts memory and functioning of the synapses in both male and female mice.Our primary objective was to comprehensively understand the impact of Aß_1­42, a specific form of Aß, when introduced into the brain's ventricles, focusing on memory processes associated with the hippocampus, a brain region vital for learning and memory.Prior research established Aß's significance in AD and memory decline. However, despite the higher prevalence of AD in females, the connection between Aß, memory, and sex differences required further exploration. Furthermore, findings from experiments utilizing Aß transgenic mice have offered conflicting outcomes. Here, by administering Aß_1­42 to male and female mice, we systematically assessed memory using cognitive tasks. Results were consistent: memory deficits were evident in both sexes, persisting for up to 17 days post-injection.Delving deeper, we explored alterations in synaptic plasticity, a cornerstone of learning and memory. Our investigations unveiled disruptions in long-term potentiation (LTP) and long-term depression (LTD)­essential synaptic processes­in both male and female mice subjected to Aß_1­42 injection.These intriguing findings underscore Aß_1­42's lasting influence on memory and synaptic function, emphasizing its role in early AD-related cognitive decline. Additionally, our study highlights the potential of this experimental model to investigate early AD across sex differences, offering a promising alternative to the existing array Aß transgenic mouse models and addressing the need for a more consistent investigative framework.

Discrete magma injections drive the 2021 La Palma eruption.

Understanding the drivers of the onset, evolution, and end of eruptions and their impact on eruption style is critical in eruption forecasting and emergency management. The composition of erupted liquids is a key piece of the volcano puzzle, but untangling subtle melt variations remains an analytical challenge. Here, we apply rapid, high-resolution matrix geochemical analysis on samples of known eruption date spanning the entire 2021 La Palma eruption. Sr isotope signatures reveal distinct pulses of basanite melt driving the onset, restart, and evolution of the eruption. Elemental variations in matrix and microcrysts track progressive invasion, and draining, of a subcrustal crystal mush. Associated variations in lava flow rate, vent development, seismicity, and SO2 emission demonstrate that volcanic matrix resolves eruption patterns that could be expected in future basaltic eruptions globally.

Terapia de estrógenos vaginales y riesgo de recurrencia en mujeres con antecedente de cáncer de mama

El cáncer de mama sigue siendo la neoplasia maligna más frecuente y una de las mortales en mujeres, considerándose un importante objetivo de la salud global y prioridad en salud pública. Con el uso de terapias innovadoras, ha mejorado la supervivencia, apareciendo condiciones asociadas, como el síndrome genitourinario menopaúsico. La terapia hormonal, se utiliza para el manejo de esta condición, mejorando sustancialmente la sintomatología, e incluso, siendo en algunos casos la única solución. La más utilizada, es la terapia de estrógenos vaginales. Sin embargo, se ha descrito un posible riesgo de recurrencia de cáncer de mama con su uso. En habla hispana, no existe evidencia que haya discutido este tópico. Se llevó a cabo una búsqueda en las bases PubMed, ScienceDirect y MEDLINE, utilizando los términos "Terapia de estrógenos vaginales", "Recurrencia" y "Cáncer de mama". Se encontró, que, de forma global, la terapia de estrógenos vaginales es una opción terapéutica eficaz y segura en el manejo del síndrome genitourinario menopaúsico en mujeres con antecedente de cáncer de mama, sin incrementar el riesgo de recurrencia, a excepción de aquellas tratadas con inhibidores de la aromatasa, en quienes se recomienda el uso de otras terapias para evitar acarrear este riesgo.

Breast cancer remains the most common malignant neoplasm and one of the leading causes of mortality in women, making it a significant target for global health efforts and a public health priority. Through the use of innovative therapies, survival rates have improved, leading to the emergence of associated conditions such as genitourinary menopausal syndrome. Hormonal therapy is employed for managing this condition, significantly alleviating its symptoms and, in some cases, serving as the sole solution. The most commonly utilized approach is vaginal estrogen therapy. Nevertheless, there have been reports of a potential risk of breast cancer recurrence associated with its use. In the Spanish-speaking context, there is limited evidence discussing this topic. A search was conducted across PubMed, ScienceDirect, and MEDLINE databases, using the terms "Vaginal Estrogen Therapy", "Recurrence" and "Breast Cancer." It was determined that, on a global scale, vaginal estrogen therapy is an effective and safe therapeutic option for managing genitourinary menopausal syndrome in women with a history of breast cancer. This therapy does not appear to increase the risk of recurrence, with the exception of those undergoing treatment with aromatase inhibitors. For these individuals, alternative therapies are recommended to mitigate this potential risk.

Catalysis-free synthesis of thiazolidine-thiourea ligands for metal coordination (Au and Ag) and preliminary cytotoxic studies.

The reaction of propargylamines with isothiocyanates results in the selective formation of iminothiazolidines, aminothiazolines or mixed thiazolidine-thiourea compounds under mild conditions. It has been observed that secondary propargylamines lead to the selective formation of cyclic 2-amino-2-thiazoline derivatives, while primary propargylamines form iminothiazoline species. In addition, these cyclic thiazoline derivatives can further react with an excess of isothiocyanate to give rise to thiazolidine-thiourea compounds. These species can also be achieved by reaction of propargylamines with isothiocynates in a molar ratio of 1 : 2. Coordination studies of these heterocyclic species towards silver and gold with different stoichiometries have been carried out and complexes of the type [ML(PPh3)]OTf, [ML2]OTf (M = Ag, Au) or [Au(C6F5)L] have been synthesised. Preliminary studies of the cytotoxic activity in lung cancer cells have also been performed in both ligands and complexes, showing that although the ligands do not exhibit anticancer activity, their coordination to metals, especially silver, greatly enhances the cytotoxic activity.

The deterrent ability of Xenorhabdus nematophila and Photorhabdus laumondii compounds as a potential novel tool for Lobesia botrana (Lepidoptera: Tortricidae) management.

The grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae), is a critical pest for vineyards and causes significant economic losses in wine-growing areas worldwide. Identifying and developing novel semiochemical cues (e.g. volatile bacterial compounds) which modify the ovipositional and trophic behaviour of L. botrana in vineyard fields could be a novel control alternative in viticulture. Xenorhabdus spp. and Photorhabdus spp. are becoming one of the best-studied bacterial species due to their potential interest in producing toxins and deterrent factors. In this study, we investigated the effect of the deterrent compounds produced by Xenorhabdus nematophila and Photorhabdus laumondii on the ovipositional moth behaviour and the larval feeding preference of L. botrana. Along with the in-vitro bioassays performed, we screened the potential use of 3 d cell-free bacterial supernatants and 3 and 5 d unfiltered bacterial ferments. In addition, we tested two application systems: (i) contact application of the bacterial compounds and (ii) volatile bacterial compounds application. Our findings indicate that the deterrent effectiveness varied with bacterial species, the use of bacterial cell-free supernatants or unfiltered fermentation product, and the culture times. Grapes soaked in the 3 d X. nematophila and P. laumondii ferments had âˆ¼ 55% and âˆ¼ 95% fewer eggs laid than the control, respectively. Likewise, the volatile compounds emitted by the 5 d P. laumondii fermentations resulted in âˆ¼ 100% avoidance of L. botrana ovipositional activity for three days. Furthermore, both bacterial fermentation products have larval feeding deterrent effects (∼65% of the larva chose the control grapes), and they significantly reduced the severity of damage caused by third instar larva in treated grapes. This study provides insightful information about a novel bacteria-based tool which can be used as an eco-friendly and economical alternative in both organic and integrated control of L. botrana in vineyard.

When Competitors Join Forces: Consortia of Entomopathogenic Microorganisms Increase Killing Speed and Mortality in Leaf- and Root-Feeding Insect Hosts.

Combining different biocontrol agents (BCA) is an approach to increase efficacy and reliability of biological control. If several BCA are applied together, they have to be compatible and ideally work together. We studied the interaction of a previously selected BCA consortium of entomopathogenic pseudomonads (Pseudomonas chlororaphis), nematodes (Steinernema feltiae associated with Xenorhabdus bovienii), and fungi (Metarhizium brunneum). We monitored the infection course in a leaf- (Pieris brassicae) and a root-feeding (Diabrotica balteata) pest insect after simultaneous application of the three BCA as well as their interactions inside the larvae in a laboratory setting. The triple combination caused the highest mortality and increased killing speed compared to single applications against both pests. Improved efficacy against P. brassicae was mainly caused by the pseudomonad-nematode combination, whereas the nematode-fungus combination accelerated killing of D. balteata. Co-monitoring of the three BCA and the nematode-associated Xenorhabdus symbionts revealed that the four organisms are able to co-infect the same larva. However, with advancing decay of the cadaver there is increasing competition and cadaver colonization is clearly dominated by the pseudomonads, which are known for their high competitivity in the plant rhizosphere. Altogether, the combination of the three BCA increased killing efficacy against a Coleopteran and a Lepidopteran pest which indicates that this consortium could be applied successfully against a variety of insect pests.

Heterocycles in Breast Cancer Treatment: The Use of Pyrazole Derivatives.

Among the aromatic heterocycle rings, pyrazole -a five-membered ring with two adjacent nitrogen atoms in its structure has been postulated as a potent candidate in the pharmacological context. This moiety is an interesting therapeutic target covering a broad spectrum of biological activities due to its presence in many natural substances. Hence, the potential of the pyrazole derivatives as antitumor agents has been explored in many investigations, showing promising results in some cases. In this sense, breast cancer, which is already the leading cause of cancer mortality in women in some countries, has been the topic selected for this review, which covers a range of different research from the earliest studies published in 2003 to the most recent ones in 2021.

Plants with antioxidant activity and their potential use as sun protector agents in Costa Rica

SUMMARY Aims: To carry out a bibliographic review related to plants available in Costa Rica that have demonstrated antioxidant power and a sun protection factor (SPF) suitable to be used in sunscreen products. Methods: The bibliographic review was carried out using different descriptors and by consulting different databases. Results: Information about antioxidant power about acerola, avocado, carrots, passion fruit, moringa, banana, pumpkin and amaranth, guava, matico, ginkgo, blackberry, mango, coffee was obtained. The information obtained suggests that the mentioned plants could be used for the formulation of sunscreens. Conclusion: Sun protection products should be used every day to prevent skin damage; some sunscreens produce allergic reactions, so it is necessary to investigate natural options to be used in sun protection products. Some natural products exhibit SPF values that allow their incorporation as sun protection agents, adjuvants, or enhancers in sunscreens.

Objetivo: llevar a cabo una investigación bibliográfica sobre plantas disponibles en Costa Rica que han demostrado su poder antioxidante y un factor de protector solar (SPF) apto para ser utilizados en protectores solares. Métodos: la revisión bibliográfica se realizó utilizando diferentes descriptores y mediante la consulta en diferentes bases de datos. Resultados: se obtuvo información sobre el poder antioxidante de las plantas: acerola, aguacate, zanahoria, maracuyá, moringa, banano, calabaza y amaranto, guayaba, matico, ginkgo, mora, mango, café. La información obtenida sugiere que las plantas mencionadas podrían ser utilizadas para la formulación de protectores solares. Conclusiones: los protectores solares deben ser utilizados diariamente para prevenir el daño sobre la piel. Algunos de estos productos generan reacciones alérgicas y por esta razón es necesario investigar posibles opciones naturales para ser incorporadas en bloqueadores solares. Algunos productos naturales exhiben valores de SPF que permiten su uso como agentes protectores solares, adyuvantes o potenciadores en los bloqueadores solares.

Objetivo: realizar uma pesquisa bibliográfica sobre plantas disponíveis na Costa Rica que demonstraram poder antioxidante e um fator de proteção solar (FPS) adequado para uso em protetores solares. Métodos: a revisão bibliográfica foi realizada usando diferentes descritores e consultando diferentes bases de dados. Resultados: foram obtidas informações sobre o poder antioxidante das plantas: acerola, abacate, cenoura, maracujá, moringa, banana, abóbora e amaranto, goiaba, matico, ginkgo, amora, manga, café. As informações sugerem que as referidas plantas poderiam ser utilizadas para a formulação de protetores solares. Conclusões: protetores solares devem ser usados diariamente para prevenir danos à pele. Alguns desses produtos geram reações alérgicas e por isso é necessário investigar possíveis opções naturais para serem incorporadas aos protetores solares. Alguns produtos naturais apresentam valores de FPS que permitem seu uso como protetores solares, adjuvantes ou potencializadores em protetores solares.

Stereoselective Three-Step One-Pot Cascade Combining Amino- and Biocatalysis to Access Chiral γ-Nitro Alcohols.

The combination of small-molecule catalysis and enzyme catalysis represents an underexploited area of research with huge potential in asymmetric synthetic chemistry due to both compatibility of reaction conditions and complementary reactivity. Herein, we describe the telescopic synthesis of chiral nitro alcohols starting from commercially available benzaldehyde derivatives through the one-pot three-step chemoenzymatic cascade combination of a Wittig reaction, chiral-thiourea-catalysed asymmetric conjugate addition, and ketoreductase-mediated reduction to access the corresponding target compounds in moderate to excellent overall isolated yields (36-80 %) and high diastereomeric and enantiomeric ratios (up to >97 : 3). This represents the first example of the combination of an organocatalysed asymmetric conjugate addition via iminium ion activation and a bioreduction step catalysed by ketoreductases.

Gold-Catalyzed 1,3-Thiazine Formation and Uncommon Tautomer Isolation.

This work represents the first example of a gold-catalyzed formation of 1,3-thiazine/1,3-thiazinane by means of a catalytic approach and further uncommon isolation of the two tautomers. The developed protocol gives rise to a broad scope of 1,3-thiazine derivatives with excellent yields in short reaction times. Interestingly, different isomers could be obtained depending on the state of the compound, and in the crystal state the 1,3-thiazinane isomer is obtained, while in solution the 1,3-thiazine is the unique isomer. This work represents an interesting approach for the synthesis of potential biologically relevant molecules and a crucial precedent in tautomerism isolation and characterization.

The Pharmacist's Role in the Implementation of FASTHUG-MAIDENS, a Mnemonic to Facilitate the Pharmacotherapy Assessment of Critically Ill Patients: A Cross-Sectional Study.

FASTHUG is a mnemonic used by intensive care physicians to ensure the proper management of patients admitted to an Intensive Care Unit (ICU). FASTHUG-MAIDENS is a modified version that incorporates key pharmacotherapeutic elements such as delirium management, drug dosing, and drug interactions for an appropriate medication assessment of critically ill patients. An analytical cross-sectional study of hospitalized patients was carried out to determine aspects related to the pharmacotherapeutic management of critically ill patients that required to be optimized, to design and implement a protocol based on the FASTHUG-MAIDENS mnemonic. A total of 435 evaluations were performed to assess the status of current critical patient management. The main parameters with opportunities to be improved were analgesia, feeding, and sedation. With the implementation of MAIDENS, the parameters of analgesia, sedation, and thromboprophylaxis showed an increase in the percentage of optimal management. Furthermore, 103 drug-related problems were detected, and most of them were associated with feeding (21.3%), glucose control (11.7%), and delirium (9.7%). The FASTHUG MAIDENS protocol implementation allows for the evaluation of more vital aspects in the management of critically ill patients. The daily review of patients admitted to the ICU by a clinical pharmacist (CP) using the FASTHUG-MAIDENS checklist instead of the FASTHUG mnemonic facilitates the identification of DRPs for the performance of possible interventions by the CP to improve the pharmacotherapeutic management.

Organic mulching modulated native populations of entomopathogenic nematode in vineyard soils differently depending on its potential to control outgrowth of their natural enemies.

The entomopathogenic nematodes (EPNs) are biological control agents that are widespread in crop soils. However, traditional agricultural management practices such as cultivation and agrochemical usage can alter the soil balance that enables their occurrence and activity. Alternative strategies like mulching are commonly employed to prevent weed growth, enhance below-ground biodiversity by improving soil, organic matter content, fertility, and moisture. We hypothesized that organic mulches would favor biotic conditions for nematofauna development in crop soil, including EPNs, compared to herbicide application or tillage. Traditional (insect baits) and molecular (qPCR analysis) tools were used in this study to assess the abundance and activity of native EPNs, and the abundance of potential natural enemies, such as free-living nematode (FLN) competitors, nematophagous fungi (NF), and ectoparasitic bacteria, in soils managed with different organic mulches or traditional practices. As a model agroecosystem, we selected the vineyard, one of the most intensively managed crop systems. We compared mulches of grape pruning debris (GPD-M), straw (Str-M), and spent mushroom compost (SMC-M) in two commercial vineyards, which employed either integrated or organic pest and disease management. Following a completely randomized design, we retrieved two composite samples per plot (n = 3 per treatment in each vineyard) in April, June, and October 2020. Numbers of EPNs and selected members of their soil food web were higher in the organic than the integrated managed vineyard. Supporting our hypothesis, organic mulching overall favored nematode occurrence in both vineyards. We found higher NF abundance for Str-M, and GPD-M in the organic vineyard, which plausibly explained the lower EPN activity and occurrence compared to SMC-M in both vineyards. We conclude that the organic mulches can provide appropriate conditions for increasing nematofauna numbers but, depending on the mulch type, may also adversely affect EPNs by increasing their natural enemies. Our findings highlight the need to explore alternative farming practices to unravel complex biotic interactions that affect beneficial soil organisms in agroecosystems.

Potent Ant Deterrents Emitted from Nematode-Infected Insect Cadavers.

Most known species of entomopathogenic nematodes (EPNs) are generalist obligate parasites of insects. They kill their hosts within days after infection and mortality is mainly caused by toxins produced by bacteria that co-infect the hosts and serve as food for the nematodes. EPNs can infect a very broad spectrum of insects and these insects can therefore be expected to have evolved strategies to avoid infection. Indeed, ants are known to avoid feeding on EPN-infected insect cadavers, most likely because they are repelled by semiochemicals that emanate from the cadavers. The source and nature of these repellents are so far unknown. In a series of behavioral and chemical analytical experiments we identified hexadecanal and 2-heptadecanone as two compounds that are emitted by insect larva that are infected by the EPN Steinernema feltiae, but not by uninfected larvae. When spiking honey water with the two semiochemicals, they were confirmed to be highly deterrent to the ant Lasius niger. The environmentally benign hexadecanal and 2-heptadecanone could be employed to ward off ants and possibly other pests. Additional experiments are needed to fully determine their application potential.

Intraspecific virulence of entomopathogenic nematodes against the pests Frankliniella occidentalis (Thysanoptera: Thripidae) and Tuta absoluta (Lepidoptera: Gelechiidae).

Entomopathogenic nematodes (EPN) are excellent biocontrol agents against various insect pests. Novel biotechnological approaches can enhance their utility against insects above-ground, opening a new venue for selecting superior EPN against certain insects. We hypothesize that different populations of the same species but from different origins (habitat, ecoregion) will differ in their virulence. This study aimed to evaluate the virulence of various EPN populations against two pests of worldwide incidence and damage to high value crops: Frankliniella occidentalis (Thysanoptera: Thripidae) and Tuta absoluta (Lepidoptera: Gelechiidae). We tested 10 EPN populations belonging to three EPN species: Heterorhabditis bacteriophora (Koppert, MG-618b, AM-203, RM-102), Steinernema feltiae (Koppert, RS-5, AM-25, RM-107), and Steinernema carpocapsae (Koppert, MG-596a). Each EPN population was tested at two concentrations. Frankliniella occidentalis was tested at 160 and 80 IJs/cm2 and T. absoluta at 21 and 4 IJs/cm2. Control treatments followed the same experimental procedure but only adding distilled water. Overall, whenever different, higher IJs concentration resulted in lower adult emergence, higher larval mortality, and shorter time to kill the insects. Considering the low concentration, S. feltiae provided the best results for both insects and instars investigated, while H. bacteriophora and S. carpocapsae required a high concentration to reach similar or slightly better results. Differences among populations of each of the species were detected, but only the native populations of H. bacteriophora populations showed consistently higher control values against both insects/instar compared with the commercial one. Differences among S. feltiae and S. carpocapsae populations depended on the IJs concentration, insect, and instar. We consider S. feltiae a very promising species for their application against F. occidentalis and T. absoluta, with the Koppert population as the most consistent among the populations tested. Specific EPN-populations of S. carpocapsae and H. bacteriophora were good candidates against certain instar/insects at high concentrations. This study emphasized the importance of intraspecific variability for EPN virulence.