Abstract

Introduction

Species Implicated in Human Infestations

Biology and Life Cycle

Epidemiology of C. lectularius and C. hemipterus

Clinical Relevance

Control

Laboratory Collection, Identification, and Reporting

Specimen collection and handling

Morphologic features of adults and nymphs

Identification of the species of cimicids reported from humans

Reporting

References

Abstract

The world has experienced a major global resurgence of bed bug infestations over the past 2 decades. While bed bugs do not serve as vectors of disease, their bites and household infestations result in significant psychological distress, clinical manifestations, and economic costs. Most human bed bug infestations are caused by the “common bed bug,” Cimex lectularius, or the “tropical bed bug,” C. hemipterus. Zoonotic cimicids also occasionally feed on humans. Bites are the most commonly reported manifestation of infestations, although findings may be subtle and overlooked for some time. The bugs can be submitted to the laboratory for identification, and therefore, clinical microbiologists should be familiar with their key identifying features and how they can be differentiated from similar-appearing arthropods. This review covers the biology and epidemiology of bed bugs; aspects of laboratory collection, identification, and reporting; and the clinical implications of bed bug infestations.

Introduction

“Good night, sleep tight; don’t let the bed bugs bite.” This version of the well-known rhyme was first published in 1896 in the book What They Say in New England by Clifton Johnson, but variations of this verse can be found in the literature in the decades before [1]. While a seemingly innocent bedtime rhyme, it reflects the reality of life in colonial New England, in which residents went to bed hoping not to be bitten by these blood-sucking pests while they were sleeping. We now know that bed bugs have long been associated with human habitats, being found in references throughout history and from archaeological sites dating back 3,500 years [2]. Bed bugs were thought to have spread throughout Asia and Europe in the early centuries of the Common Era, and later traveled to the Americas aboard ships of early European sailors [3]. By the 1900s, bed bugs were estimated to be in 1/3 of the dwellings in European cities and disproportionately affected those living in poor, crowded neighborhoods. While bed bugs do not serve as vectors of disease, their bites and household infestations result in psychological distress, a range of unpleasant clinical manifestations, property loss, and other substantial economic costs [4, 5, 6]. It was only with the widespread household use of dichloro-diphenyl-trichloroethane (DDT) and other potent long-lasting pesticides throughout the 1940s to 1960s that the prevalence of bed bug infestations significantly decreased worldwide [3].
Unfortunately, the world is now experiencing a major resurgence in bed bug infestations, with an explosion of reports beginning around the turn of the century [4, 7]. Although the exact cause of this resurgence is unknown, it is thought to be due to multiple factors, including widespread resistance to commonly used pesticides, increased domestic and international travel, and the decline in public health pest control programs that occurred in the latter half of the 1900s [8].

Highlights

Abstract

Graphical abstract

Abbreviations

Keywords

1. Introduction

2. De novo identification of mitochondrial proteins

2.1. In silico strategies

2.2. Experimental strategies

2.3. Integrative biology strategies

3. From proteins to functions: deorphanizing the unknown

3.1. In silico strategies

3.2. Experimental strategies

4. Perspectives

CRediT authorship contribution statement

Declaration of Competing Interest

Acknowledgments

References

Abstract

Human mitochondria are complex and highly dynamic biological systems, comprised of over a thousand parts and evolved to fully integrate into the specialized intracellular signaling networks and metabolic requirements of each cell and organ. Over the last two decades, several complementary, top-down computational and experimental approaches have been developed to identify, characterize and modulate the human mitochondrial system, demonstrating the power of integrating classical reductionist and discovery-driven analyses in order to de-orphanize hitherto unknown molecular components of mitochondrial machineries and pathways. To this goal, systematic, multiomics-based surveys of proteome composition, protein networks, and phenotype-to-pathway associations at the tissue, cell and organellar level have been largely exploited to predict the full complement of mitochondrial proteins and their functional interactions, therefore catalyzing data-driven hypotheses. Collectively, these multidisciplinary and integrative research approaches hold the potential to propel our understanding of mitochondrial biology and provide a systems-level framework to unraveling mitochondria-mediated and disease-spanning pathomechanisms.

1. Introduction

Mitochondria are essential organelles for cellular and organismal life in virtually all eukaryotes (Fig. 1). Present-day human mitochondria originated from the integration of an endosymbiotic α-proteobacterium into a host cell, therefore exchanging their independence for a semi-autonomous life [1,2]. By the late 1990s, comparative genomics analyses of α-proteobacteria genomes and quantitative two-dimensional gels of highly purified mitochondria suggested that the mammalian mitochondrial proteome consists of ∼1,000–1,500 distinct proteins [3,4]. The majority of those proteins derive from the eukaryotic genome, whereas the prokaryotic genome was significantly reduced during the transition from endosymbiotic bacterium to organelle [2] (Fig. 2A). To date, only a handful of protein-coding genes – thirteen in mammals – are still retained in the mitochondrial DNA (mt-DNA) of almost all eukaryotes. Therefore, most of the mitochondrial proteome is encoded from the nuclear genome, translated in the cytosol, and then targeted and imported into the organelle.

Strikingly, only 1% of mammalian mitochondrial proteins are allocated to ATP synthesis, highlighting that the organelle’s functions reach far beyond energy production (Fig. 1). Indeed, mitochondria are at the core of multiple cellular pathways, including the biosynthesis of precursors for cholesterol, estrogen, testosterone and hemoglobin; the regulation of redox and ion homeostasis; the activation of antiviral responses and cell death. Adding an additional layer of complexity, mitochondrial functions are tied to the specialized tasks and physiology of different cell types, tissues, and organisms [5]. For instance, only between 40–70 % of the human mitochondrial proteome is conserved in commonly used model systems such as unicellular eukaryotes (e.g. S. cerevisiae) and invertebrates (e.g. C. elegans, D. melanogaster) (Fig. 2B). Furthermore, over 15 % of the mitochondrial system shows tissue-specificity [6] and profound differences even among cell types of the same tissue [6,7].

Abstract

Keywords

1. Introduction

2. What is life?

3. What is a virus?

4. Do any virus-like systems achieve closure to efficient causation?

5. Conclusion

Declaration of Competing Interest

Acknowledgements

Appendix A. Supplementary data

References

Abstract

Whether or not viruses are alive remains unsettled. Discoveries of giant viruses with translational genes and large genomes have kept the debate active. Here, a fresh approach is introduced, based on the organisational definition of life from within systems biology. It views living as a circular process of self-organisation and self-construction which is ‘closed to efficient causation’. How information combines with force to fabricate and organise environmentally obtained materials, given an energy source, is here explained as a physical embodiment of informational constraint. Comparing a general virus replication cycle with Rosen’s -system shows it to be linear, rather than closed. Some viruses contribute considerable organisational information, but so far none is known to supply all required, nor the material nor energy necessary to complete their replication cycle. As a result, no known virus replication cycle is closed to efficient causation: unlike cellular obligate parasites, viruses do not match the causal structure of an -system. Analysis based in identifying a Markov blanket in causal structure proved inconclusive, but using Integrated Information Theory on a Boolean representation, it was possible to show that the causal structure of a virocell is not different from that of the host cell.

Introduction

The first half of 2020 has seen one particular virus (SARS-Cov2) dominate world news, so much that viruses appear to be at the forefront of public interest in biological research and in this context an old debate has reemerged: “Are viruses alive?”. According to an informal survey (Racaniello, 2014), expert opinion remains divided roughly a third each between yes, no and don’t know. This is not surprising given that the debate seems still to be resolved. Eleven years ago, an emphatic statement was made against including viruses among the living (Moreira and Lopez-Garcia, 2009), quickly countered by (sometimes indignant) responses of matching boldness (Claverie and Ogata (2009); Hegde et al. (2009)) and more nuanced responses (e.g. Forterre (2010b)). The discovery of giant viruses(Raoult and Forterre, 2008; Abergel et al., 2015; Claverie and Abergel, 2018), especially the Pandoraviruses, having genome sizes reaching that of parasitic eukaryotes (Nad`ege et al., 2013) and Tupanviruses with their batteries of translational genes (Abrah˜ao and et al., 2018; Rodrigues et al., 2020) has further stirred the debate (e.g. Claverie and Abergel (2010); Abergel et al. (2015); Brandes and Linial (2019)). It also attracted philosophers of science who having analysed the debate, concluded that it is misguided (van Regenmortel, 2016; Koonin and Starokadomskyy, 2016). Whether or not viruses belong within the category of living has again become highly topical and contentious.

1- Introduction

2- Multi-layer NPs for CRISPR-Cas9 delivery

3- Novel building blocks for multi-layer NPs

4- Conclusions and perspective

References

Abstract

The clustered regularly interspaced short palindromic repeat (CRISPR) has great potential to revolutionize biomedical research and disease therapy. The specific and efficient genome editing strongly depends on high efficiency of delivery of the CRISPR payloads. However, optimization of CRISPR delivery vehicles still remains a major obstacle. Recently, various non-viral vectors have been utilized to deliver CRISPR tools. Many of these vectors have multi-layer structures assembled. In this review, we will introduce the development of CRISPR-Cas9 systems and their general therapeutic applications by summarizing current CRISPR-Cas9 based clinical trials. We will highlight the multi-layer nanoparticles (NPs) that have been developed to deliver CRISPR cargos in vitro and in vivo for various purposes, as well the potential building blocks of multi-layer NPs. We will also discuss the challenges in making the CRISPR tools into viable pharmaceutical products and provide potential solutions on efficiency and biosafety issues.

Introduction

In recent years, a series of programmable DNA nuclease-dependent genome editing techniques have been developed to enable efficient genetic manipulation in eukaryotes, particularly in mammalian cells [1-3]. These genome-editing techniques used for gene knock-out or knock-in predominately include meganucleases, zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and the CRISPR-Cas system [4-7]. These technologies all employ endonucleases to induce double strand breaks (DSB) at intended sites in the genome, followed by DSB repair through different mechanisms including non-homologous end joining (NHEJ), homologous recombination (HR), homology-mediated end joining (HMEJ) and microhomology-mediated end joining (MMEJ) [8]. Among these genome editing techniques, CRISPR-Cas9 is a gene editing system derived from the bacterial adaptive immune system, which is capable of combating the invasive viral genome under the guidance of short sequence RNA. CRISPR-Cas9 system is highly versatile because of its simplicity and high efficiency, moreover, any genome sequence theoretically can be edited by this system. In principle, the whole genome can be site-specifically modified at the genetic level in cells and tissues with CRISPR-Cas9 system, which further allows researchers to study the relationship between gene mutations and biological phenotypes. CRISPR-Cas9 system has driven innovative applications from basic biology research to biotechnology and medicine [9].

1- Introduction

2- Materials and methods

3- Results

4- Discussion

5- Conclusions

References

Abstract

High-resolution melting (HRM) analysis followed by sequencing was applied for determination of bacteria grown on plates isolated from farmed mussels (Mytilus galloprovincialis) during their storage at 4 °C. The V3–V4 region of the 16S rRNA gene from the isolates was amplified using 16S universal primers. Melting curves (peaks) and high resolution melting curves (shape) of the amplicons and sequencing analysis were used for differentiation and identification of the isolated bacteria, respectively. The majority of the isolates (a sum of 101 colonies, from five time intervals: day 0, 2, 4, 6 and 8) from non-selective solid medium plates were classified in four bacterial groups based on the melting curves (peaks) and HRM curves (shape) of the amplicons, while three isolates presented distinct HRM curve profiles (single). Afterwards, sequencing analysis showed that the isolates with a) the same melting peak temperature and b) HRM curves that were >95% similar grouped into the same bacterial species. Therefore, based on this methodology, the cultivable microbial population of chill-stored mussels was initially dominated by Psychrobacter alimentarius against others, such as Psychrobacter pulmonis, Psychrobacter celer and Klebsiella pneumoniae. P. alimentarius was also the dominant microorganism at the time of the sensory rejection (day 8). Concluding, HRM analysis could be used as a useful tool for the rapid differentiation of the bacteria isolated from mussels during storage, at species level, and then identification is feasible by the sequencing of one only representative of each bacterial species, thus reducing the cost of required sequencing.

Introduction

The determination of seafood quality from their harvest to consumer table is of high importance for the aquaculture sectors, fishery trade associations, food industry and food authorities. The enumeration of Aerobic Plate Counts (APC) or alternatively Specific Spoilage Organisms (SSOs) is a common way to evaluate freshness of stored seafood. SSOs constitute a small fraction of the initial total microbiota which grows faster than the rest microorganisms during storage reaching higher population densities and produces metabolites that cause the organoleptic rejection of the product (Boziaris and Parlapani, 2016; Gram and Huss, 1996). In this context, the monitoring of the diversity and dynamic of SSOs lets us know which microorganisms prevail against others under the specific storage conditions, e.g., temperature (Parlapani et al., 2015b). Using plate-based against culture-independent approach, we have the advantage to isolate microorganisms for further studies regarding their spoilage potential and activity which can lead to the characterization of them as key players of seafood spoilage (Parlapani et al., 2017). Culture-dependent identification of seafood microbiota has been traditionally studied by phenotypic and biochemical tests, however these are laborious and usually lack discriminatory power giving failed results (Nisiotou et al., 2014). For these reasons, other, alternative, rapid, accurate and reliable methodologies have been developed. The 16S rRNA gene sequence analysis has been conducted by analyzing (amplification and sequencing) numerous isolates e.g., 50% or more of the total colonies grown on plates (Parlapani and Boziaris, 2016; Parlapani et al., 2015a, 2015b).

A healthy symbiotic relationship between corals and S ymbiodiniaceae relies on suitable temperature and adequate nutrients including trace metals. Besides global warming, trace metal deficiency has been shown to cause coral bleaching, a phenomenon responsible for extensive coral reef degradation around the world. How trace metal deficiency impacts Symbiodiniaceae and coral symbiosis is poorly understood, however . In this study, we applied RNA -seq to investigate how Fugacium kawagutii responds to the deficiency of five trace metal s (Fe2+, Zn2+, Cu2+ , Mn2+, Ni2+). We identified 685 to 2805 differentially expressed genes (DEGs) from these trace metal deficiency conditions, among which 372 were commonly regulated by all the five trace metal s and were significantly enriched in energy metabolism (e.g. fatty acid synthesis) . Furthermore, genes associated with extracellular matrix (ECM), cell surface structure and cell adhesion were impacted, suggesting that the ability of recognition and adhesion of F. kawagutii may be altered by trace metal deficiencies. In addition, among the five metals, Fe2+ deficiency exhibited the strongest influence, with F e -rich redox elements and many antioxidant synthesis genes being markedly down -regulated, indicative of adaptive reduction of Fe demand but a compromised ability to combat oxidative stress . Overall , deficiency of trace metal s (especially Fe) seems to repress growth and ability of ROS scavenging , elevat e energy metabolism and innate immunity, and alter cell adhesion capability, with implications in symbiosis disruption and coral bleaching.

Introduction

Mutualistic nutritional symbioses between coral animals and photosynthetic dinoflagellates of Symbiodiniaceae are the foundation of the highly biodiverse and productive coral reef ecosystem ( Peixoto et al., 2017). A symbiotic Symbiodiniaceae provide s its coral host with vital photosynthesis product s that can meet up to 95% of the coral ’s energy requirements; in exchange, the coral host provide s inorganic nutrients and serve s as shelter (Muscatine and Porter, 1997) for the symbiont . This mutualistic relationship, however, is delicate and susceptible to the environment factors including thermal stress, high light and extreme salinity (Davy et al., 2012; Kuanui et al., 2015; Nielsen et al., 2018; Skirving et al., 2019). These stress condition s often lead to the expulsion , death, or pigment loss of the Symbiodiniaceae from the host, known as coral bleaching. Global warming and anthropogenic activities have been responsible for massive bleaching and coral degradation , and posed major threats to the precious coral reef ecosystem around the world (Hughes et al ., 2017). Reef coral s liv e in tropical nutrient -poor waters , and they can experience limitation of nutrients, including trace metals ( Measures and Vink 2000; Obata et al ., 2008 ). It has been shown that trace metal deficiency can also induce coral bleaching (Ferrier -Pages et al ., 2018). Trace metal s are essential components of electron transport chains or important cofactors for enzymes involved in various biological processes, such as chlorophyll synthesis, nitrate reduction, and photoprotection or photorepair (Twining and Baines, 2013; Andresen, et al., 2018) .

2- Materials and Methods

3- Results and Discussion

4- Conclusions

References

Introduction

Wound healing is a complex multistep and multicellular biological process, traditionally divided into four overlapping phases known as haemostasis, infammation, proliferation, and remodelling [1]. Infammation and hypoxia are mutually interdependent: hypoxia-elicited infammation is implicated in the outcomes of a wide range of human diseases. Te delay in wound healing and wound chronicity are directly linked to persistent infammation. On the other hand, infammatory states are frequently characterised by tissue hypoxia, or by the stabilisation of hypoxia-dependent transcription factors [2, 3]. Te healing process is regulated by multiple signals such as growth factors, cytokines, chemokines, matrix metalloproteinases (MMPs) and extracellular macromolecules [4, 5]. Upon skin injury, innate immune cells (neutrophils and macrophages) are recruited to the site of injury to remove cellular debris and to secrete mediators able to activate keratinocytes, endothelial cells and fbroblasts. Angiogenesis is crucial to ensure an adequate supply of blood for tissue repair and wound healing [6]. Endothelial cells proliferate, demolish basement membrane and migrate to form new blood vessels starting from the ones located at wound edges. Fibroblasts produce collagen, elastin, proteoglycans and other glycoproteins of the extracellular matrix, which then mature outside the cells. Some fbroblasts develop into myofbroblasts that cause contraction of the wound. Keratinocytes proliferate and migrate from the edges of the wound to restore a confuent epithelium. Migration and proliferation of all the cell types is regulated by complex mechanisms of inhibition and stimulation by growth factors and chemoattractants.

Microbial fuel cells (MFCs) are devices that transform organic matters in wastewater into green energy. Microbial fuel cells systems have strong nonlinearity and high coupling, which involves control science, microbiology, electrochemistry and other disciplines. According to the requirements of microbial fuel cell system for model robustness and accuracy, we designed a comprehensive model optimization framework. Firstly, the influence of uncertain parameters on system was analyzed by combining global sensitivity analysis with uncertainty analysis. In accordance with analysis results, the uncertain parameters were optimized. Secondly, based on the optimized stochastic model, a simplified model was proposed by combining variable selection with neural networks. The results shown that the proposed framework can deeply analysis the influence of uncertain parameters on output, and provide theoretical basis for experimental research. It fully simplifies the original MFCs model, and has guiding significance for other types of fuel cells.

Introduction

Microbial Fuel Cells (MFCs) which required in lots of field [1]–[3] have received a widespread concern in the past several years as a green energy. MFCs can be considered as equipment realizes a conversion of bioenergy to green energy, taking the organism as the fuel and direct generation of electricity by microbial redox reactions. Many efforts have been directed to the power generation principle and application of MFCs [4]–[6]. The basic reaction principle is that the bacteria oxidize the substrate in the anaerobic anode through a catalyst, and the electrons generated by the anode chamber are transported to the aerobic cathode through an external circuit and form water molecules. Compared with hydrogen oxygen fuel cells and other chemical cells, MFCs use organisms as biocatalysts and possesses the advantages of high resourceusing rate, less pollution and mild reaction conditions. However, there are several obstacles constrain the development of MFCs. The main disadvantage of MFCs operation compared to other renewable energy, such as geothermal energy, tidal energy, nuclear power is the low power output, which limits the ability to drive high power devices. Over the past few years, the main direction of research was microbial cultivation, substrate analysis and electrode modification, various systems were built for different types of MFCs [7], [8]. In addition, a large number of experimental studies have also found the impact of operational parameters on MFCs performance, such as ionic concentration [9], temperature [10], [11], pH [12], substrate nitrogen concentration [13], [14], and electrode distance [15].

Expanded polystyrene (EPS) is a synthetic polymer that is widely applicable in the fields of food packaging, equipment protection and civil construction. Aiming to replace EPS, biofoams were developed utilizing mycelia of the macrofungi Pycnoporus sanguineus, Pleurotus albidus and Lentinus velutinus in a medium formulated with sawdust and wheat bran. Sample characterization was obtained by scanning electron microscopy (SEM), thermal analysis and infrared spectroscopy with Fourier Transform; density and compression strength were analysed as mechanical properties. The main results include that the compression strengths of biofoams from P. sanguineus, P. albidus and L. velutinus were 1.3, 0.4, and 1.3 MPa, respectively, which exceed that of EPS (0.4 MPa). The thermal stability of the biofoams was lower than that of EPS; however, they were stable up to 350
C. Biofoams are denser than EPS, with values of 0.3 and 0.03 g cm3 , respectively. The data obtained for biofoams categorize this material as sustainable substitute for EPS in some applications, while at the same time, reducing the environmental impact caused by sawdust and EPS.

Introduction

The growing search for biodegradable materials has shifted the interest of the scientific community towards the development of biodegradable products (Vaisanen et al., 2017). These materials can replace synthetic petroleum-related products, such as expanded polystyrene (EPS), which is used in a huge variety of shapes and applications (Poletto et al., 2011; Song et al., 2009; Treinyte et al., 2018). Polystyrene is a widely employed polymer (Shimomura et al., 2016; Yousif and Haddad, 2013). In its expanded form, EPS is used in the form of plates or blocks for preparing slabs, as protective packaging for domestic appliances, in crash helmets and as electrical or thermal insulators in homes, among other applications (Chen and Liu, 2004; Haghi et al., 2006). However, there are some drawbacks because it is petroleum-related and is not biodegradable, which means that it takes many years to degrade if left in the environment (Araújo et al., 2008). After its use, EPS is unduly disposed of, piling up in landfills or even in the environment, which compromises the conventional degradation processes because certain compounds present in the polymer chains can act as a barrier against degradation by organic compounds (Araújo et al., 2008). Still, EPS contains benzene, which has been classified as a human carcinogen (IARC group 1) since 1979, with sufficient evidence to support the claim that it causes leukaemia (Loomis et al., 2017). EPS also contains styrene, a substance that can also trigger the development of various neoplasms (IARC Monographs Vol 121 Group).

1- Introduction

2- Antagonism

3- Facilitation

4- Host community interactions

5- Habitat modification by ecosystem engineers

6- Challenges and future goals

7- Conclusions

References

Abstract

Entomopathogenic nematodes (EPNs) have potential to control many soil-dwelling insect pests but have been limited in their usage, partly by their unpredictable field performance. Numerous abiotic and biotic factors are thought to contribute to this poor predictability, but the exact impacts and relative importance of these factors in affecting EPN performance in the field are not well understood. Previous studies have highlighted diverse interactions between EPNs and other members of the soil community, from plants and fungi to arthropods and annelids. These interactions may help or hinder EPNs in a variety of ways. However, current research has yet to determine how many of these interactions influence EPN performance under field conditions, specifically, if they contribute to the variability limiting EPN efficacy and wide-scale adoption. Here we outline current knowledge of these interactions as well as challenges and avenues for future research, such as greater integration of EPN research with soil animal and rhizosphere ecology, that will better elucidate the potential, limitations, and proper use of EPNs in pest management.

Introduction

Since the discovery of entomopathogenic nematodes (EPNs) in 1923 and their first commercialization sixty years later, thirteen EPN species of the genera Steinernema and Heterorhabditis have been commercially cultivated and marketed for use in a wide array of agricultural and horticultural systems (Lacey et al., 2015). EPN infective juveniles (IJs) invade insect bodies through the mouth, anus, spiracles, or cuticle (Lewis et al., 2006; Wang and Gaugler, 1998) and release their bacterial symbionts (Xenorhabus spp. bacteria for Steinernema spp. nematodes, and Photorhabdus spp. bacteria for Heterorhabditis spp. nematodes) into the insect’s hemolymph. The bacteria release toxins to kill the insect, though sometimes are aided by venom proteins and anti-immune agents produced by the nematodes themselves (Lu et al., 2017), and proliferate in the cadaver. The IJs consume the bacteria, complete their development, and reproduce. After one or more generations of nematodes inside the cadaver, new IJs leave to seek new hosts in the soil (Kaya and Gaugler, 1993; Lewis and Clarke, 2012). When using EPNs against pests in agricultural and horticultural systems, IJs are commonly applied onto soil as an aqueous suspension sprayed through the same kind of device used to apply a chemical pesticide. Many other application techniques exist, such as applying EPNs through drip irrigation systems or applying them contained within bait capsules or already-infected insect cadavers (Shapiro-Ilan and Dolinski, 2015). EPNs can effectively provide a non-toxic, environmentally benign alternative to chemical insecticides for the control of some soil-dwelling pests, including white grubs (Grewal et al., 2005), citrus root weevil (Shapiro-Ilan et al., 2005, 2002), and mole crickets (Parkman et al., 1996). However, despite these and other successes (Georgis et al., 2006), extensive use of EPNs in agriculture is limited to a few markets, including citrus orchards (Shapiro-Ilan et al., 2005) and vegetables in greenhouses (Dolinski et al., 2012; Lacey and Georgis, 2012). Despite the safety of EPNs for humans, other vertebrates, and many non-target invertebrates (Georgis et al., 2006; Lacey and Georgis, 2012), their variable performance and persistence remain important factors restricting their adoption by pest managers (Georgis et al., 2006; Georgis and Gaugler, 1991; Shapiro-Ilan et al., 2002). For instance, many studies of EPN efficacy against scarab grubs in turf and nursery crop systems report highly variable control even within the same EPN species (Georgis et al., 2006; Grewal et al., 2005). Increasing knowledge of how abiotic and biotic soil characteristics affect and contribute to variability in EPN performance and persistence will be a crucial task to better optimize EPNs for soil pest management. In addition, while many applied EPNs do not persist in soil longer than a few weeks or months (Ebssa and Koppenhöfer, 2011; Gaugler et al., 1997; Smits, 1996; Susurluk and Ehlers, 2008), some native EPN populations, adapted to a particular environment, have been shown to persist over multiple years when isolated, cultured, and applied to the soil (Koppenhöfer and Fuzy, 2009; Shields et al., 1999). This interest in using persistent EPN populations underscores the need for understanding the biotic and abiotic factors that limit or promote EPN persistence.