Conservative Surrogate Research Articles

Survival of Salmonella enterica and Enterococcus faecium on Abiotic Surfaces During Storage at Low Relative Humidity

Currently, there is limited knowledge on the survival of bacteria on surfaces during postharvest handling of dry products such as onions. Extended survival of microorganisms, coupled with a lack of established and regular, validated cleaning or sanitation methods could enable cross-contamination of these products. The aim of the study was to evaluate the survival of a potential surrogate, Enterococcus faecium, and Salmonella enterica on typical onion handling surfaces, polyurethane (PU), and stainless steel (SS), under low relative humidity. The influence of onion extract on the survival of E. faecium and Salmonella on PU and SS was also investigated. Rifampin-resistant E. faecium NRRL B-2354 and a five-strain cocktail of Salmonella suspended in 0.1% peptone or onion extract were separately inoculated onto PU and SS coupons (2 × 2 cm), at high, moderate, or low (7, 5, or 3 log CFU/cm2) levels. The inoculated surfaces were stored at ∼34% relative humidity and 21°C for up to 84 days. Triplicate samples were enumerated at regular intervals in replicate trials. Samples were enriched when populations fell below the limit of detection by plating (0.48 log CFU/cm2). Scanning electron microscopy was used to observe the cell distribution on the coupons. Reductions of E. faecium of less than ∼2 log were observed on PU and SS over 12 weeks at all inoculum levels and with both inoculum carriers. In 0.1% peptone, Salmonella populations declined by 2 to 3 log over 12 weeks at the high and moderate inoculum levels; at the low inoculum level, Salmonella could not be recovered by enrichment at 84 days. Survival of E. faecium and Salmonella was significantly (P < 0.05) enhanced over 84 days of storage when suspended in onion extract, where cells were covered by a layer of onion extract. E. faecium might have utility as a conservative surrogate for Salmonella when evaluating microbial survival on dry food-contact surfaces.

222 nm far-UVC light markedly reduces the level of infectious airborne virus in an occupied room

An emerging intervention for control of airborne-mediated pandemics and epidemics is whole-room far-UVC (200–235 nm). Laboratory studies have shown that 222-nm light inactivates airborne pathogens, potentially without harm to exposed occupants. While encouraging results have been reported in benchtop studies and in room-sized bioaerosol chambers, there is a need for quantitative studies of airborne pathogen reduction in occupied rooms. We quantified far-UVC mediated reduction of aerosolized murine norovirus (MNV) in an occupied mouse-cage cleaning room within an animal-care facility. Benchtop studies suggest that MNV is a conservative surrogate for airborne viruses such as influenza and coronavirus. Using four 222-nm fixtures installed in the ceiling, and staying well within current recommended regulatory limits, far-UVC reduced airborne infectious MNV by 99.8% (95% CI: 98.2–99.9%). Similar to previous room-sized bioaerosol chamber studies on far-UVC efficacy, these results suggest that aerosolized virus susceptibility is significantly higher in room-scale tests than in bench-scale laboratory studies. That said, as opposed to controlled laboratory studies, uncertainties in this study related to airflow patterns, virus residence time, and dose to the collected virus introduce uncertainty into the inactivation estimates. This study is the first to directly demonstrate far-UVC anti-microbial efficacy against airborne pathogens in an occupied indoor location.

Heat inactivation of aqueous viable norovirus and MS2 bacteriophage.

This study aimed to compare the heat inactivation kinetics of viable human norovirus with the surrogate, MS2 bacteriophage as well as assess the decay of the RNA signal. Human intestinal enteroids were used to analyze the heat inactivation kinetics of viable human norovirus compared to the surrogate MS2 bacteriophage, which was cultured using a plaque assay. Norovirus decay rates were 0.22 min-1, 0.68 min-1, and 1.11 min-1 for 50°C, 60°C, and 70°C, respectively, and MS2 bacteriophage decay rates were 0.0065 min-1, 0.045 min-1, and 0.16 min-1 for 50°C, 60°C, and 70°C, respectively. Norovirus had significantly higher decay rates than MS2 bacteriophage at all tested temperatures (P=.002-.007). No decrease of RNA titers as measured by reverse transcription-PCR for both human norovirus and MS2 bacteriophage over time was observed, indicating molecular methods do not accurately depict viable human norovirus after heat inactivation and treatment efficiency is underestimated. Overall, our data demonstrate that MS2 bacteriophage is a conservative surrogate to measure heat inactivation and potentially overestimates the infectious risk of norovirus. Furthermore, this study corroborates that measuring viral RNA titers, as evaluated by PCR methods, does not correlate with the persistence of viable norovirus under heat inactivation.

Can environmental legislation protect a threatened apex predator across different land tenures?

Ecological impact assessments are undertaken in compliance with legislative mandates to evaluate the effects of proposed habitat modification. This task becomes complex when evaluating the impacts on highly mobile species like apex predators. Despite their importance to ecosystem function, environmental policies may inadequately protect apex predator habitat. Here we provide a case study that examines the efficacy of legislation and impact assessment tools in protecting habitat for a wide-ranging and threatened apex predator. The high resource requirements of apex predators, and their utilisation of large areas of high-quality habitat make them ideal conservation surrogates for other less resource demanding species, and as such good case studies in assessing the effectiveness of policy. The powerful owl (Ninox strenua) occurs across many landscape types throughout its distribution, including large tracts of private property and public landholdings, making this species difficult to assess through impact assessments. To examine the level of legislative protection for powerful owls, and how well their habitat use is captured, we compared GPS tracking data to environmental policy and industry impact assessment tools. We found that legislation has limited potential to protect powerful owl habitat and owls are likely dismissed from impact assessments due to their cryptic and wide-ranging behavioural traits. The existing legislative safeguards seem inadequate, and these shortcomings are likely contributing to species decline. There is a critical need for policy to be applicable to both public and private land tenure, and for legislation and impact assessment tools to incorporate research data for effective conservation and management.

Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for Cryptosporidium Oocyst Removal

Monitoring the removal of Cryptosporidium oocysts in water treatment plants is a challenge, particularly in developing countries, and the use of surrogates has proven necessary. Two surrogates already investigated and recognized by the scientific community are aerobic spore-forming bacteria (ASFB) and fluorescent polystyrene microspheres (ME). In this context, this study evaluates and compares the performance of upflow direct filtration and downflow direct filtration, with emphasis on the removal of ASFB and ME as a surrogate of Cryptosporidium oocyst removal. Pilot filtration experiments were carried out with low turbidity Paranoá Lake water (average—3.7 NTU) with ASFB varying from 7 × 102 to 5.5 × 103 CFU/100 mL. In some experiments, water was spiked with microspheres, aiming for 105 ME/L. Two operational conditions were evaluated: (1) filters operating with the same filtration rate (5 m/h); (2) filters operating with the same flow rate of 59.41 L/h. In general, the downflow filter presented a slightly higher removal efficiency than the upflow filter but the differences were not considered statistically significant in most cases. The removal efficiency of microspheres (3 to 5 log) was higher than that of ASFB (1.2 to 4 log) in both filters, corroborating that the removal of ASFB is a conservative surrogate of the removal of Cryptosporidium.

Variety among physical landscape features in natural grassland-plantation forestry mosaics promotes diverse butterfly assemblages

Various physical landscape features across local and regional spatial scales contribute to heterogeneity. This means that ostensible maintenance of physical landscape features as representatives of heterogeneity (i.e., a meso-filter conservation approach) can contribute to conservation of insect assemblages. Using butterflies as model organisms, we investigate the conservation value of specific physical landscape feature types (rocky areas, wetlands, and gullies) relative to open grasslands, across 32 study sites in a natural grassland-plantation forestry mosaic in South Africa. We found that all considered landscape feature types had equal species richness and diversity levels compared to open grasslands. Yet, β-diversity (mostly accounted for by species turnover) was overall high between rocky areas, wetlands, and open grasslands, resulting from associations between some butterfly species and certain landscape feature types. Gullies were occupied by nested assemblages of rocky areas and open grasslands, suggesting that gullies have lower conservation importance, and should be targets for restoration. Topography and butterfly food plant availability further influenced β-diversity patterns and should also be considered when adopting a meso-filter conservation approach. β-diversity was also high among similar feature types, suggesting that a variety of landscape features that encapsulates environmental variation at a landscape scale can best conserve regional butterfly assemblages. While our focus was on butterflies, we anticipate these findings to be relevant to other insect groups, given that butterflies have successfully been used as conservation surrogates for other terrestrial insect taxa (e.g., grasshoppers) in the same area.

Defining Daily Disposable Contact Lens Wear in a Clinical Study.

The U.S. Food and Drug Administration regulates contact lenses as prescription medical devices and defines daily disposable lenses for single use; however, safety comparisons between daily disposable and reusable lenses rely on the lens-wearing regimen. When inappropriately discerned, studies may erroneously report replacement regimen, resulting in inaccurate risk rates. This study aimed to explore different measures for defining daily disposable wearers in the context of a clinical study. A secondary analysis of data from five multisite fieldings (n = 1059) from the Contact Lens Risk Survey was performed. Descriptive statistics were used to examine self-reported lens replacement, use of lens case, and manufacturer's recommended replacement frequency as defined by the participants' selection of their habitual lenses using a photographic aide. Daily disposable wearers were identified as reporting daily replacement (by self-report and lens identification) and not using a lens case. If there was a discrepancy among these three factors, the lens assignment was assessed as a majority response (two of three) or as missing if conflicting information was reported. The cohort was approximately two-thirds (68.7%) female and ranged from 12 to 33 years of age. A total of 154 participants (14.5%) were classified as daily disposable wearers and 896 (84.6%) as reusable wearers. Congruence was observed among all three daily disposable assignment factors for only 106 wearers (68.8%). The greatest discrepancy among daily disposable wearers was the report of using a lens case (n = 32 [20.8%]). In contrast, reusable lens wearers were more likely to report agreement across all three factors (n = 798 [89.1%], P < .001). This analysis suggests that the report of not using a lens case is a more conservative surrogate for true single-use lens wear, as one in five may be storing and reusing their daily disposable lenses.

Estimating provisional margins of exposure for data-poor chemicals using high-throughput computational methods.

Current computational technologies hold promise for prioritizing the testing of the thousands of chemicals in commerce. Here, a case study is presented demonstrating comparative risk-prioritization approaches based on the ratio of surrogate hazard and exposure data, called margins of exposure (MoEs). Exposures were estimated using a U.S. EPA’s ExpoCast predictive model (SEEM3) results and estimates of bioactivity were predicted using: 1) Oral equivalent doses (OEDs) derived from U.S. EPA’s ToxCast high-throughput screening program, together with in vitro to in vivo extrapolation and 2) thresholds of toxicological concern (TTCs) determined using a structure-based decision-tree using the Toxtree open source software. To ground-truth these computational approaches, we compared the MoEs based on predicted noncancer TTC and OED values to those derived using the traditional method of deriving points of departure from no-observed adverse effect levels (NOAELs) from in vivo oral exposures in rodents. TTC-based MoEs were lower than NOAEL-based MoEs for 520 out of 522 (99.6%) compounds in this smaller overlapping dataset, but were relatively well correlated with the same (r 2 = 0.59). TTC-based MoEs were also lower than OED-based MoEs for 590 (83.2%) of the 709 evaluated chemicals, indicating that TTCs may serve as a conservative surrogate in the absence of chemical-specific experimental data. The TTC-based MoE prioritization process was then applied to over 45,000 curated environmental chemical structures as a proof-of-concept for high-throughput prioritization using TTC-based MoEs. This study demonstrates the utility of exploiting existing computational methods at the pre-assessment phase of a tiered risk-based approach to quickly, and conservatively, prioritize thousands of untested chemicals for further study.

Using functional traits to identify conservation priorities for the world's crocodylians

AbstractOver half of all crocodylians are threatened with extinction, with many species considered to be functionally extinct throughout their historical ranges. How such losses impact crocodylian functional diversity (FD) and its conservation is poorly understood, but can be investigated using measurable traits. Where such information is unavailable, phylogenetic diversity (PD) has been proposed as an effective strategy to capture FD, but this assumption is not well tested.We constructed a global trait database for 28 extant crocodylians, and quantified their FD, distinctiveness and groupings. Functionally distinctive crocodylians include the most and least evolutionarily distinct species, likely because unusual trait values and combinations can be produced by both evolutionary isolation and evolutionarily recent adaptive radiation. We identified four functional groups of crocodylians, within which species have similar ecological roles. Highly distinctive species, such as the gharial, fit less well into functional groups.We combined functional distinctiveness (FUD) and threat ranking scores to prioritise species for conservation. The metric is termed Ecologically Distinct and Globally Endangered (EcoDGE), and we tested how well it operates to preserve crocodylian FD among extant Crocodylia. Under current extinction scenarios, 32%–38% of crocodylian FD might be lost within 100 years. Losses increase to 48% if all threatened species go extinct, with Asia identified as a hotspot of threatened FD in crocodylians. Highly threatened distinctive species lead this extinction scenario, exacerbated by clusters of species sharing traits linked to high extinction risk. These traits include habitat specialism and lower reproductive investment; in contrast, species that tolerate climate extremes are more resilient.Prioritising at‐risk species based on FUD and threat status appears to be an effective way to conserve present‐day crocodylian diversity. Conservation prioritisation based on the EcoDGE metric performed well to minimise projected losses in FD. Among extant crocodylians, FD losses are projected when high diversity overlaps with high extrinsic threats.We then examined the utility of PD‐based measures as surrogates for FD conservation, to better understand the advantages and drawbacks of such substitutions. A PD‐based measure such as the Evolutionarily Distinct and Globally Endangered metric provided an effective tool to capture FD in our tests.Read the freePlain Language Summaryfor this article on the Journal blog.

Can at‐risk species serve as effective conservation surrogates? Case study in northeasternUSshrublands

AbstractTargeted, single‐species management and ecosystem‐based management are generally considered disparate conservation approaches. In imperiled ecosystems, these approaches may be complementary, when habitat management for targeted at‐risk species provides broad ecosystem benefits through an umbrella or surrogate species effect. In the northeastern United States, extensive management has been ongoing since 2011 to restore declining habitat for an at‐risk shrubland habitat specialist, the New England cottontail (Sylvilagus transitionalis), with the goal that other shrubland‐obligate wildlife will also benefit; yet, the efficacy of these efforts has not been evaluated. In this study, we assessed whether habitat management targeting New England cottontail provides conservation benefits for shrubland‐obligate birds. Specifically, we (1) identified shrubland‐obligate birds that are indicative of the microhabitat conditions and habitat types suitable for New England cottontails, and (2) determined microhabitat and patch‐level influences on shrubland bird occupancy at sites occupied by or managed for New England cottontail. Through avian point count surveys and indicator species analyses, we identified 12 shrubland‐obligate bird species on patches occupied by New England cottontail and in microhabitat conditions suitable for New England cottontail. Occupancy models for five shrubland bird species further identified species‐specific habitat associations. Generalized linear models showed that shrubland bird species richness was positively associated with herbaceous vegetation and low shrubs, indicating that shrublands managed for the purpose of cottontail colonization can also benefit a suite of shrubland birds before the habitat is dense enough to provide cover for cottontails. Our findings show that managing habitat for New England cottontail on a variety of site types can maintain a range of microhabitat conditions to support a high diversity of shrubland‐obligate birds. These findings provide evidence for broad ecosystem benefits of managing for New England cottontail and exemplify the value of at‐risk habitat specialists as conservation surrogates in imperiled ecosystems.

Predicting the biodiversity hotspots of macrozoobenthos in the Yangtze river basin

Identifying the biodiversity hotspots could enrich our understanding for biodiversity conservation. The Yangtze River Basin (YRB) is seriously threatened by multiple stressors leading to rapid biodiversity declines, thus urgently requires an integrated biodiversity conservation. Based on field samplings and the literatures, we described the macrozoobenthos compositions in different reaches and water bodies. We then predicted suitable habitat areas for the main groups, and linked those distributions with key environmental variables. Finally, we analyzed biodiversity hotspots (BHs) of macrozoobenthos and compared them with BHs of large aquatic animals (including fishes, Waterfowls, Yangtze finless porpoise, etc.), and discussed the applicability of selecting macrozoobenthos as biodiversity surrogate for biodiversity conservation. A total of 1033 taxa were recorded. From the upper to lower of YRB, genera number of Oligochaeta and Mollusca increased, of EPT (Ephemeroptera, Plecoptera, Trichoptera) decreased, and of Chironomidae barely changed. In different water bodies, genera number of Oligochaeta, Mollusca, Chironomidae are the highest in lakes of the mid-lower YRB, while that of EPT are the highest in tributaries. Key environmental variables were water body types, elevation and max temperature of the warmest month. The total BHs areas of macrozoobenthos and large aquatic animals in the upper, and mid­lower YRB were 3.54 × 105 km2 and 2.95 × 105 km2, 2.95 × 105 km2 and 1.70 × 105 km2, respectively. The overlapping BHs were 2.0 × 105 km2 and 1.1 × 105 km2, respectively. The BHs of macrozoobenthos had a wider range, and included most BHs of large aquatic animals. Meanwhile, BHs of macrozoobenthos could indicate some habitats those were difficult to cover by selecting large aquatic animals as conservation targets, e.g., seasonal streams and water bodies that suffered from human disturbances. Based on these results, we argue that macrozoobenthos is a good biodiversity surrogate for biodiversity conservation.

Incorporating human exposure information in a weight of evidence approach to inform design of repeated dose animal studies

Human health risks from chronic exposures to environmental chemicals are typically estimated from potential human exposure estimates and dose-response data obtained from repeated-dose animal toxicity studies. Various criteria are available for selecting the top (highest) dose used in these animal studies. For example, toxicokinetic (TK) and toxicological data provided by shorter-term or dose range finding studies can be evaluated in a weight of evidence approach to provide insight into the dose range that would provide dose-response data that are relevant to human exposures. However, there are concerns that a top dose resulting from the consideration of TK data may be too low compared to other criteria, such as the limit dose or the maximum tolerated dose. In this paper, we address several concerns related to human exposures by discussing 1) the resources and methods available to predict human exposure levels and the associated uncertainty and variability, and 2) the margin between predicted human exposure levels and the dose levels used in repeated-dose animal studies. A series of case studies, ranging from data-rich to data-poor chemicals, are presented to demonstrate that expected human exposures to environmental chemicals are typically orders of magnitude lower than no-observed-adverse-effect levels/lowest-observed-adverse-effect levels (NOAELs/LOAELs) when available (used as conservative surrogates for top doses). The results of these case studies support that a top dose based, in part, on TK data is typically orders of magnitude higher than expected human exposure levels.

Selection of a SARS-CoV-2 Surrogate for Use in Surface Disinfection Efficacy Studies with Chlorine and Antimicrobial Surfaces.

Initial recommendations for surface disinfection to prevent SARS-CoV-2 transmission were developed using previous evidence from potential surrogates. To the best of our knowledge, no appropriate surrogate for SARS-CoV-2 has been identified or confirmed for chlorine and antimicrobial surface disinfection. We completed a study to evaluate the efficacy of two hypothesized antimicrobial surfaces, and four chlorine solutions on nonporous and porous surfaces, against SARS-CoV-2 and three potential SARS-CoV-2 surrogates [coronavirus mouse hepatitis virus (MHV) and bacteriophages Phi6 and MS2], to identify a BSL-1 or BSL-2 virus to use in future studies. We found SARS-CoV-2 can be reduced >4 log10 on porous and nonporous surfaces within 30 s upon exposure to 0.5% NaOCl. The results indicate coronavirus MHV-GFP is inactivated faster than SARS-CoV-2 (MHV-GFP ≥ 6.08 log10; SARS-CoV-2 = 0.66 log10 at 30 s with 0.05% NaOCl on steel) and MS2 is inactivated more slowly. Phi6 is inactivated like SARS-CoV-2, and we propose Phi6 as a slightly conservative surrogate for SARS-CoV-2 chlorine disinfection. Additionally, disinfection of bacteriophages on wood was challenging, and exposure to antimicrobial surfaces had no disinfection efficacy as tested. We recommend using 0.5% chlorine on surfaces for a minimum of 30 s of contact to disinfect SARS-CoV-2 and recommend additional research on Phi6 disinfection with varied surfaces and conditions.

Raptor breeding sites indicate high taxonomic and functional diversities of wintering birds in urban ecosystems

With ongoing rapid urbanization, urban biodiversity conservation is becoming a primary issue for the maintenance of urban ecosystem functions, and given that birds play valuable ecosystem roles, their preservation is a matter of both ecological and social importance. Although it is generally considered that urban areas have low biodiversity and ecosystem value, these areas can serve as important wintering grounds for both resident and migratory birds. However, as comprehensive surveys of such biota are time- and resource-consuming, it would be useful to establish efficient conservation surrogates that could be used to identify areas of conservation importance. In this study, I evaluated the efficacy of raptor habitats as a conservation surrogate for high avian taxonomic and functional diversities in urban ecosystems in the wintering season. From December 2019 to February 2020 (wintering season), avian species that appeared within 500 m of 30 Northern Goshawk (Accipiter gentilis) breeding sites in eastern Kanagawa Prefecture, Japan, were investigated using point counts. I subsequently measured species richness and dendrogram-based functional diversity (FD) as indicators of avian taxonomic diversity and the ecosystem functions provided by birds, respectively, and performed the same procedures at 30 randomly selected points in areas similar to goshawk breeding habitats. Thereafter, using generalized linear models, I compared species richness and FD at sites with and without goshawk nests. I accordingly found that the presence of goshawk breeding sites is significantly positively associated with avian species richness and FD, explaining most of the variability in these data (species richness: 66.4 %, FD: 66.0 %). In conclusion, these findings indicate that goshawk breeding sites could be used as a conservation surrogate to identify and preserve habitat hotspots for wintering birds in urban ecosystems. These results can provide a basis for implementing appropriate conservation measures to maintain avian diversity in urban ecosystems.

Thermal inactivation kinetics of Salmonella and Enterococcus faecium NRRL B-2354 on dried basil leaves

The enhanced heat resistance of Salmonella developed at low water activity makes it a serious challenge to eliminate them during thermal processing. The objectives of this research are to (i) investigate the effect of water activity on thermal inactivation of Salmonella cocktail (Agona, Tennessee, Mbandaka, Montevideo, and Reading) in dried basil leaves, and (ii) evaluate Enterococcus faecium NRRL B-2354 as an appropriate surrogate for Salmonella in dried basil leaves. Dried basil leaves, inoculated with a Salmonella cocktail and E. faecium separately, were equilibrated to different water activities (aw: 0.40, 0.55, and 0.70) in a humidity-controlled chamber. The basil samples were packed (1.6 ± 0.1 g) in aluminum pouches and thermally treated at 70, 75, and 80 °C using a dry heating method for 0–180 min to obtain the thermal death curve. The microbial survival data was fit using two primary models (Log-linear and Weibull model). Results from AICc showed that the log-linear model fits well for thermal inactivation of both microorganisms. As the aw decreases from 0.70 to 0.40 at 75 °C, the D-value increases from 3.30 to 9.14 min for Salmonella and 6.53 to 14.07 min for E. faecium. Based on the AICc values, the modified Bigelow model fits the D-values better than the response surface model for both the microorganisms. The kill ratio of surrogate to pathogen ranged from 1.4 to 2.8, indicating that it is a conservative surrogate for Salmonella for performing validation of the thermal pasteurization process. The identification of suitable surrogate and development of modified Bigelow model will help the spice industry in developing the thermal processes for improving the safety of basil leaves.

The hidden risk of using umbrella species as conservation surrogates: A spatio-temporal approach

The use of a charismatic umbrella species as surrogate for sympatric species is often advocated as an efficient approach. However, comprehensive evaluations from a spatio-temporal perspective are few, leaving the long-term effectiveness of such practices remain uncertain. We modeled the habitat change for giant panda and eight sympatric mammalian species using observations from extensive camera trap surveys and remotely-sensed environmental predictors during two time periods, early 2000s and early 2010s. We found that the degree and spatial pattern of the habitat suitability change varied among species. The overall habitat suitability improved between the early 2000s and early 2010s for seven target species including giant panda Ailuropoda melanoleuca, suggesting positive effects of several recent conservation projects in restoring natural landscapes for certain species groups. However, the current nature reserve system designed for giant pandas did not adequately cover critical landscapes for several species, including the two species who experienced net habitat loss, Endangered forest musk deer Moschus berezovskii and Vulnerble Asiatic black bear Ursus thibetanus. To conserve multiple species simultaneously in this region, we recommend establishing nature reserves for other threatened species who share dissimilar habitat needs with giant panda, and adding a widely distributed omnivores, Asiatic black bear, as a surrogate species in central and southwest China. These findings reveal the risk of using umbrella species as a conservation shortcut in protecting animal communities in China, and have substantial implications for other regions where the majority of the conservation funds are directed toward a single charismatic species.

Soil Solarization to Eradicate Soilborne Phytophthora spp. in Container Nurseries with Surface Gravel1

Abstract To describe the effect of soil solarization in the presence of a gravel layer on the soil surface of container nurseries, we investigated belowground temperatures and soil water potential during solarization with different thicknesses of a surface gravel layer (2.5 cm, 7.5 cm, or no gravel) (1 in, 3 in, or no gravel) in relation to survival of soilborne Phytophthora spp. inoculum. In field trials conducted for 4 weeks with Phytophthora ramorum Werres and Phytophthora pini Leonian in San Rafael, California and with P. pini in Corvallis, Oregon, infested rhododendron leaf inoculum was placed on the surface, and at 5 cm (2 in) and 15 cm (6 in) below the surface. In solarized plots with thicker layers of gravel, inoculum buried in the soil layer was killed in shorter treatment periods by higher elevated temperatures. Inoculum at the surface and within the gravel layer was also killed, but showed greater tolerance to heat under the lower water potential conditions as compared to the soil layer. P. pini has a significantly longer survival in heat than P. ramorum, allowing it to serve as a conservative surrogate for P. ramorum in testing solarization outside the quarantine facility. This study demonstrates how presence of a gravel layer influences soil solarization effectiveness in reducing Phytophthora inoculum survival. Index words: Phytophthora ramorum, Phytophthora pini, soil disinfestation, disease management, soil temperature, soil water potential, ornamentals. Species used in this study: Phytophthora ramorum Werres, de Cock &amp; Man in't Veld, Phytophthora pini Leonian.

Evaluation of Enterococcus faecium NRRL B-2354 as a surrogate for Salmonella enterica in milk powders at different storage times and temperatures

While the increase in thermal resistance of microorganisms at reduced water activity is demonstrated for low-moisture food products, the effect of storage time on the thermal resistance of microorganisms in low-moisture foods is not well established. As low-moisture foods are stored for long periods and are used as ingredients, cross-contamination can occur at any time period before the lethality step. Therefore, this study was designed to investigate the effect of storage time (30, 60, and 90 d) on the thermal resistance of Salmonella and Enterococcus faecium NRRL B-2354 in milk powders at a low water activity of 0.10 (conservative level). In this study, 2 milk powders, whole milk powder (WMP) and nonfat dry milk (NFDM), were inoculated with a 5-serotype Salmonella cocktail or E. faecium and equilibrated to a water activity of 0.10. The thermal resistance of Salmonella and E. faecium in WMP and NFDM were determined at different storage times (30, 60, and 90 d) at 85°C. The storage time had no effect on the thermal inactivation kinetics of Salmonella within 90 d of storage at 85°C. In the second part of this study, isothermal treatments were also conducted at higher temperatures (90 and 95°C) to evaluate the suitability of E. faecium as a surrogate for Salmonella in milk powders. The D-values of Salmonella in WMP with 30 d of storage at 85, 90, and 95°C were 7.98, 3.35, and 1.68 min. The corresponding values for E. faecium were 16.96, 7.90, and 4.16 min. Higher D-values of E. faecium indicates that it is a conservative surrogate. Similar results were found for NFDM. In general, D-values of both microorganisms are slightly higher in NFDM than WMP. Two primary models (log-linear and Weibull) were compared for their goodness-of-fit. The Weibull model was found to be more appropriate than the log-linear model. This study provides valuable information for establishing process validation for the pasteurization of milk powders.

Genomic Modeling as an Approach to Identify Surrogates for Use in Experimental Validation of SARS-CoV-2 and HuNoV Inactivation by UV-C Treatment.

Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2) is responsible for the COVID-19 pandemic that continues to pose significant public health concerns. While research to deliver vaccines and antivirals are being pursued, various effective technologies to control its environmental spread are also being targeted. Ultraviolet light (UV-C) technologies are effective against a broad spectrum of microorganisms when used even on large surface areas. In this study, we developed a pyrimidine dinucleotide frequency based genomic model to predict the sensitivity of select enveloped and non-enveloped viruses to UV-C treatments in order to identify potential SARS-CoV-2 and human norovirus surrogates. The results revealed that this model was best fitted using linear regression with r2 = 0.90. The predicted UV-C sensitivity (D90 – dose for 90% inactivation) for SARS-CoV-2 and MERS-CoV was found to be 21.5 and 28 J/m2, respectively (with an estimated 18 J/m2 obtained from published experimental data for SARS-CoV-1), suggesting that coronaviruses are highly sensitive to UV-C light compared to other ssRNA viruses used in this modeling study. Murine hepatitis virus (MHV) A59 strain with a D90 of 21 J/m2 close to that of SARS-CoV-2 was identified as a suitable surrogate to validate SARS-CoV-2 inactivation by UV-C treatment. Furthermore, the non-enveloped human noroviruses (HuNoVs), had predicted D90 values of 69.1, 89, and 77.6 J/m2 for genogroups GI, GII, and GIV, respectively. Murine norovirus (MNV-1) of GV with a D90 = 100 J/m2 was identified as a potential conservative surrogate for UV-C inactivation of these HuNoVs. This study provides useful insights for the identification of potential non-pathogenic (to humans) surrogates to understand inactivation kinetics and their use in experimental validation of UV-C disinfection systems. This approach can be used to narrow the number of surrogates used in testing UV-C inactivation of other human and animal ssRNA viral pathogens for experimental validation that can save cost, labor and time.

Raptor breeding sites as a surrogate for conserving high avian taxonomic richness and functional diversity in urban ecosystems

Preserving biodiversity and ecosystem functions in rapidly increasing urban areas has become a focal issue of conservation science. With limited budgets and human resources, a potentially efficient conservation strategy is to prioritize important areas in urban ecosystems, based on raptor habitats. Here, northern goshawk (Accipiter gentilis) breeding sites in urban Kanagawa, Japan were used to explore the effectiveness of raptor habitats as conservation surrogates for biodiversity and ecosystem function. The presence of birds was recorded within 500 m of 37 goshawk breeding sites through point counts in the breeding season of 2019. Species richness and dendrogram-based functional diversity (FD) were then determined as measures of biodiversity and ecosystem function, respectively. As controls, 50 sites with landscape compositions similar to goshawk breeding sites were also evaluated. The analysis involved two generalized linear models using species richness and FD as response variables and the presence/absence of goshawk breeding sites as covariates. Goshawk breeding sites had a significant positive effect on species richness and FD, explaining most of their variance (species richness: 63.0%, FD: 56.9%). In conclusion, this study confirmed that goshawk breeding sites that maintain high urban biodiversity and ecosystem function can be used to prioritize and preserve important areas for conservation.