Attachment Strength Research Articles

Building students' attachment strength with higher education institutes using intangible resources: role of institutional branding

PurposeThe present study has been carried out to study whether and how different aspects of brand management (brand identity, brand image and brand meaning) are instrumental in maintaining and enhancing attachment strength of students with higher education institutes (HEIs). Further, to understand what brand management aspect channels the impact of what branding driver on attachment strength in most effective manner.Design/methodology/approachThe study analysed combined mediating effects as well as specific mediating effects to test the mediating role of brand management aspects.FindingsThe study reveals that brand image plays highest mediating role among all aspects of brand management. HEIs need to enhance service quality because brand image carries the highest influence of service quality on attachment strength. Similarly, brand identity carries the highest influence of heritage on attachment strength. Brand meaning carries the highest influence of competence and reputation on attachment strength.Research limitations/implicationsThe present study, based on empirical research, has built the framework and mechanism for creating attachment strength utilising the intangible resources of HEIs through brand management. The present study examines how specific intangible resources exhibit varying influences on attachment strength via distinct brand management mediation effects.Practical implicationsThe present study provides framework for designing branding strategies to build and channelise necessary intangible resources of branding for nourishing and nurturing attachment strength.Originality/valueThe present study contributes to scarce branding literature in context of HEIs. The study proposes role of HEI branding in developing students' attachment strength with their HEIs.

Evaluation of Listeria monocytogenes biofilms attachment and formation on different surfaces using a CDC biofilm reactor

Listeria monocytogenes can adapt, persist, and form biofilms on food premises surfaces, representing a challenge for food safety, since they led to disease transmission, food contamination and spoilage during production. Physical interventions (scrubbing and wiping) can help controlling formation, nevertheless when biofilms are formed, they are usually very resistant to current control strategies used in the food industry. Biofilm attachment and formation is influenced by environment characteristics, substrate properties and microbial motility. The purpose of this study was to evaluate the ability of L. monocytogenes to attach and form biofilms on different surfaces (wood, nylon, and polycarbonate) representative of the materials used during produce harvesting and storage. Multi-strain L. monocytogenes biofilms were grown in a CDC Biofilm reactor at 20 ± 2 °C up to 96-h and characterized for: a) attachment strength by enumerating cells after rinsing; b) hydrophobicity and interfacial tension by contact angle measurements; c) biofilm architecture by Laser Scanning Confocal Microscopy. All experiments were done in triplicate. Material, incubation, and solvent significantly affected the hydrophobicity and wetting properties of L. monocytogenes biofilms (P < 0.05). The type of material and incubation time significantly influenced hydrophobicity and wetting properties of L. monocytogenes biofilms (P < 0.05). Highest contact angle and lowest interfacial tension were observed on polycarbonate coupons. The data presented contributes to understanding Listeria biofilms grow on different surfaces commonly used in produce harvesting and storage. The data obtained in this study can be used when evaluating intervention strategies to control this pathogen in food premises.

Design and Testing of a Superelastic Nitinol Tissue Attachment Mechanism for Long-Term Gastrointestinal Device Retention

AbstractIngestible devices have become a popular means for diagnosing and treating the gastrointestinal (GI) tract due to their noninvasive nature. However, their residency period in the GI tract is limited by the transit time through it. In previous work, we designed a tissue attachment mechanism (TAM) inspired by parasitic worms' attachment methods, which were tested for implanting biosensors or drug delivery payloads to the small intestine with a swallowable capsule robot. In that work, the attachment success rate was 91.7%, and the average attachment duration of the TAM was 32.2 h after factorial optimization of major design factors. This work develops a novel nitinol TAM (NTAM) for improving the attachment duration using the shape-changing properties of nitinol. The attachment strength of the NTAM to the intestinal tissue was assessed both ex vivo and in vivo. The attachment duration of the NTAMs in live porcine models was evaluated from radiographic images, and histological analysis of the attachment location of an NTAM was performed after euthanasia. The NTAM was 100% successful in an attachment strength study and achieved a maximum attachment duration of 13 days, while the average attachment duration was 85.63 ± 77.83 h. Histological analysis did not report any permanent damage to the tissue. This work shows a 2.7-fold improvement in attachment duration over the previous design. This work has demonstrated a method of prolonged attachment to the intestinal wall through a swallowable device, which can be used for long-term drug delivery or biosensing.

Development and performance of a clear aligner film loaded with sustained release hydrogen peroxide gel

Introduction: Clear aligner treatment (CAT) has become popular over recent years because it is both comfortable and aesthetically acceptable. However, most of patients undergoing orthodontic treatment request dental bleaching. A safe and controlled bleaching treatment at the same time as the clear aligner treatment can save time and improve patient satisfaction with the outcome of the treatment.Aim: This study was aimed to develop a thermoforming film loaded with hydrogen peroxide as a clear aligner and detect its efficiency on teeth blenching and its influence on shear bonding strength for attachment.Methods: The thermoforming film loaded with sodium alginate-dopamine/Mesoporous silica nanoparticles compound gel was immersed in 6 wt% hydrogen peroxide solution and the hydrogen peroxide was loaded into mesoporous silica nanoparticle channels by capillary action. Then, a thermoforming film loaded with sustained-release hydrogen peroxide gel was made. Six dentition models were prepared with 90 isolated human premolars and divided into the experiment group, the condition control group and the blank control group, respectively. Then, the experiment group wore the clear aligner made by the thermoforming film loaded with hydrogen peroxide for 40 days; the conditional control group wore the clear aligner made by the ordinary thermoforming film for 40 days; and the blank control group wore no clear aligner. The aligners were updated every 10 days and the color of teeth was measured every 10 days. Tooth color should be determined by specific parameters (L, a* and b*). What’s more, in order to determine the influence of the thermoforming film loaded with sustained-release hydrogen peroxide gel on shear bonding strength for attachment. The shear bonding strength of attachment of isolated premolars were measured.Results: Isolated premolars treated by bleaching experiments showed an increase in L value (ΔL = 7.76 ± 0.64) and a decrease in both a* (Δa = −0.82 ± 0.12) and b* (Δb = −3.10 ± 0.21) values. However, the isolated premolars in conditional control group and blank control group exhibited that an decrease in L value (ΔLCCG = −0.91 ± 0.24; ΔLBCG = −0.86 ± 0.15)and a increase in both a* (ΔaCCG = 0.19 ± 0.05; ΔaBCG = 0.18 ± 0.04) and b* (ΔbCCG = 0.43 ± 0.11; ΔbBCG = 0.31 ± 0.10) value. While the shear bonding strength for attachment after bleaching was 22.78 ± 2.28 MPa, which had no significant change compared with the shear bonding strength for attachment without bleaching experiment (22.21 ± 2.77 MPa) (p &amp;gt; 0.05). Conclusion: A thermoforming film featuring the sustained release of hydrogen peroxide had a good bleaching effect on isolated teeth and had no significant influence on the shear bonding strength for attachment.

The longitudinal interplay between insecure attachment behaviors and psychosocial strengths among children in child welfare services.

Children who have experienced maltreatment are more likely to have disrupted attachments, fewer psychosocial strengths, and poorer long-term psychosocial outcomes. However, few studies have examined the interplay between attachment security and psychosocial strengths among children involved in therapeutic services in the context of the child welfare system. The present longitudinal study examines the insecure attachment behaviors and psychosocial strengths of 555 children referred to the Therapeutic Family Care program (TFCP) in Cobourg, Ontario between 2000 and 2019. The children were assessed by their caregivers on a regular basis using the Assessment Checklist for Children (ACC) and the complementary strengths-focused ACC+ measure. Average age of children at baseline was 9.57 years (SD = 3.51) and 229 (41.26%) were female. We conducted growth curve and random intercepts cross-lagged panel models to test the longitudinal interplay between insecure attachment behaviors and strengths. Results suggest that females' attachment security improved, males' attachment security worsened, and both males and females developed strengths over time. Further, analyses revealed a directional effect, whereby fewer insecure attachment behaviors predicted more psychosocial strengths approximately 6 months later. Implications for attachment-oriented and strengths-based services in the context of child welfare are discussed.

Учет переувлажнения грунтов при проектировании нагельного крепления склонов

Nail slope support has proven itself as an effective engineering protection measure, which is used to increase the stability of slopes, and involves the installation of drilling-injection ground nails together with a flexible cover system. The article considers the issue of improving the existing design methodology of this type of structure, which will include an assessment of the overall stability of the slope, an assessment of the local stability of the surface layer, considering soil moisture saturation, checking the strength of the nail on the ground and material, as well as checking the strength of the nail attachment (ground nail and steel network) on slice. To achieve this goal, there was carried out a selection of soil nailing support for the considered engineering-geological section using the Plaxis 2D PC and there was offered an analytical method for calculating slope stability. The authors also propose a method that can be used for assessing the strength characteristics of soils of the surface layer, considering excessive soil water saturation.

Survival and attachment of Listeria monocytogenes on bell peppers and influence of attachment time on efficacy of chlorine

Strong bacterial attachment or biofilm formation on produce surfaces may result in limited penetration ability of sanitizers. This study evaluated the effect of the attachment level of Listeria monocytogenes during storage on the efficacy of chlorine treatment on bell pepper surfaces. Bell peppers inoculated with L. monocytogenes were stored at 4 °C and 25 °C, and attachment strength (SR) and the efficacy of chlorine were examined during storage. The L. monocytogenes population at 4 °C decreased significantly from 6.41 log CFU/g at 1 h to 4.25 log CFU/g at 72 h while remaining constant at all times at 25 °C (6.41 log CFU/g at 1 h to 5.72 log CFU/g at 72 h). The SR value of bacteria at 4 °C remained constant throughout the storage while at 25 °C it remained similar until 48 h and increased significantly at 72 h (0.72). Chlorine washing significantly reduced the bacterial level in the samples stored for 1 h and all the samples stored at 25 °C as compared to washing with water. The survival and attachment of bacterial cells were found to be significantly (P < 0.05) better at 25 °C than at 4 °C. Efficacy of chlorine was affected by the attachment of bacteria.

Drying conditions alter the defensive function of seed mucilage against granivores

Abstract Environmental conditions alter the function of many plant traits that drive species interactions, producing context‐dependency in the outcomes of those interactions. Seed mucilage is a common, convergently evolved trait found in thousands of plant species. When wetted, the seed coat swells into a viscid mass; when dried, the mucilage strands strongly cement the seed to whatever it is in contact with. This binding to the ground has been previously shown to protect seeds from granivory. Previous research found both that mucilage volume—and the correlated attachment strength—are higher in species from hot, dry, areas suggesting an environmental component of this trait's function. Here, we (1) quantified the effect of temperature on attachment across many species in a lab setting, (2) tested the potential mechanism behind this correlation by accelerating desiccation speed without changing temperature, and (3) tested whether these relationships introduce context dependency of the defensive function of mucilage in the field, using field trials with harvester ants. We found that (1) increasing temperature during mucilage drying strongly reduced the force needed to dislodge seeds for most species, (2) drying time was likely the driving mechanism behind the loss of attachment strength at higher temperatures, not temperature per se, (3) seeds attached to substrate during higher temperatures or under accelerated drying conditions were far more susceptible to granivory. Synthesis. These results show not only the mechanism behind an abiotic modification of a functional trait of seeds, but that this change majorly alters a key interaction contributing to seed survival. These results add to a small, but growing, literature on the importance of seed mucilage in seed survival and demonstrate strong and largely predictable context‐dependency in this trait's defensive function.

High–reactive powder concrete on the basis of organic nanomodifikatorov

A significant range of organic and mineral binders produced by the industry allows for a wide variety of combinations, providing a variety of resulting compositions. This, in turn, makes it necessary to establish general regularities in the formation of their properties. An attempt is made in this article. The results of studies of the properties of concrete, which are a composition of Portland cement, fine aggregate and mineral–organic complex, intended for the creation of special structures. It is shown that the use of the organic component of the mineral–organic complex of micelle–forming surfactants or polyalcohols leads to the sealing of the inner surfaces of the pores that are formed in concrete, which leads to an increase in the strength of concrete. It has been proven that the most effective use of the mineral is as a mineral component of complex organic compounds containing so–called d–elements, such as iron. The currently widely used mineral–organic compositions of the first type are, as a rule, "mineral binder – organic polymer" or "mineral binder – bitumen (tar)" systems. These types of mineral–organic compositions have undergone quite serious tests and have been tested in operation and have not sufficiently confirmed their effectiveness. But, as you know, these types of organic materials have the disadvantage of aging, which is accompanied by depolymerization (polymer) or a change in structure (asphalts, tars). Therefore, the durability of this type of resistance is limited by the organic component of the mineral–organic composition. It is known that the adsorption properties of derivatives of higher fatty acids depends on the length of the hydrocarbon radical. This is due to the strength of attachment of derivatives of higher fatty acid to the mineral surface. This largely depends on the solubility of the compositions are formed. The solubility of these compounds is, in turn, is determined by the order of solubility of the corresponding salts higher fatty acids. The solubility of these compounds, in turn, determined by the solubility of the respective salts of fatty acids. the authors obtained a mineral–organic material which is a system of "mineral binder based on calcium – fatty acid – a substance containing iron". Mechanism of structure obtained mineral–organic material explained as follows. As is well known, are unsaturated higher fatty acids with two or more double bonds with oxygen independently oxidized.

Role of Salmonella Newport cell surface structures on bacterial attachment and transfer during cucumber peeling.

Fresh cucumbers have been recognized as a vehicle in foodborne disease outbreaks since several multistate outbreaks of salmonellosis linked to fresh cucumbers occurred in the United States. Little is known about how microbial cell surface characteristics that are known to affect adhesion can influence bacterial cross-contamination and transfer. This study investigated the role of S. Newport cell surface components on bacterial attachment and transfer in cucumbers. Wild type Salmonella Newport and its transposon mutants were used to inoculate cucumbers. Attachment strength of S. Newport wild type to cucumber was not significantly different than that of mutants. Log10 percent transfer of mutant strains to edible flesh was not different from the wild type. Significantly less wild type Salmonella remained on the peel and transferred to the peeler than one mutant did, but not the other. Our results suggest that while curli and cellulose enhance Salmonella attachment to surface of cucumbers, there appear to be other mechanisms and factors that govern Salmonella transfer in cucumbers.

Membrane attachment and fusion of HIV-1, influenza A, and SARS-CoV-2: resolving the mechanisms with biophysical methods.

Attachment to and fusion with cell membranes are two major steps in the replication cycle of many human viruses. We focus on these steps for three enveloped viruses, i.e., HIV-1, IAVs, and SARS-CoV-2. Viral spike proteins drive the membrane attachment and fusion of these viruses. Dynamic interactions between the spike proteins and membrane receptors trigger their specific attachment to the plasma membrane of host cells. A single virion on cell membranes can engage in binding with multiple receptors of the same or different types. Such dynamic and multivalent binding of these viruses result in an optimal attachment strength which in turn leads to their cellular entry and membrane fusion. The latter process is driven by conformational changes of the spike proteins which are also class I fusion proteins, providing the energetics of membrane tethering, bending, and fusion. These viruses exploit cellular and membrane factors in regulating the conformation changes and membrane processes. Herein, we describe the major structural and functional features of spike proteins of the enveloped viruses including highlights on their structural dynamics. The review delves into some of the case studies in the literature discussing the findings on multivalent binding, membrane hemifusion, and fusion of these viruses. The focus is on applications of biophysical tools with an emphasis on single-particle methods for evaluating mechanisms of these processes at the molecular and cellular levels.

The relationship between attachment to pets and mental health: the shared link via attachment to humans

BackgroundSeveral studies have investigated the relationship between emotional attachment to pets and mental health with the majority of studies finding a negative relationship between emotional attachment to pets and mental health. Interestingly, attachment to pets differs from attachment to humans with studies showing that humans with an insecure attachment style form a particularly strong emotional attachment to their companion animals. Human attachment style is also related to mental health with secure attachment being associated with superior mental health. Building on those findings, the current study aimed at exploring the role of attachment to humans in the relationship between emotional attachment to pets and mental health.MethodsIn this cross-sectional online survey (N = 610) we assessed the strength of emotional attachment to pets and attachment to humans. We further collected pet specific data as well as mental health burden in a sample of German dog owners (Mage=33.12; 92.79% women). We used a mediation model estimating the indirect link between emotional attachment to pets and mental health burden via human attachment and the direct link between emotional attachment to pets and mental health burden simultaneously.ResultsWe found that attachment to humans fully mediated the positive association between emotional attachment to pets and mental health burden. A stronger emotional attachment to one’s dog was associated with lower comfort with depending on or trusting in others, whereby lower comfort with depending on or trusting in others was related to higher mental health burden. Moreover, a stronger attachment to one’s dog was also related to a greater fear of being rejected and unloved (Anxiety), which was, in turn, associated with a higher mental health burden.ConclusionOur findings suggest that the positive link between emotional attachment to pets and mental health burden is fully accounted for by its shared variance with insecure attachment to humans in a sample mostly comprising self-identified women. Future studies need to examine whether strong emotional bonds with pets may evolve as a compensatory strategy to buffer difficult childhood bonding experiences.

Parents’ views on facilitating and inhibiting factors in the development of attachment relationships with their children with severe disabilities

Being confident as attachment figures is not self-evident for parents of children with severe or profound intellectual disabilities (SPID) given the children’s limited clear communicative responses. The current study drew upon the Attachment Strengths and Needs Interview to get an overview of factors that parents identify as influencing their parent-child attachment relationships. Inductive semantic thematic analysis was conducted on 23 semi-structured interviews (including responses of 35 parents). These were the parents of children (1–9 years) with a severe or profound intellectual (or multiple) disability. The results showed that parents mentioned a large number of inhibiting and facilitating factors related to developing attachment relationships with their children. Adopting an ecological systems perspective, these influences were organised in a micro-, meso-, macro-, exo- and chrono-level. This implies that not only factors related to the child (and his/her disability) were mentioned, but also factors related to (amongst others) the parents, the parent-child and family interactions, the broader environment and policy. Concluding, from parents’ perspectives, it seemed that the factors influencing the (development of) attachment relationships can be positive and negative, are versatile, layered in different levels, interconnected and not necessarily linked to their children’s disability. Both generic factors across parents and specific factors, related to individual families, should be taken into account to provide tailored support.

LRP-1-dependent control of calpain expression and activity: A new mechanism regulating thyroid carcinoma cell adhesion

The low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional endocytic receptor mediating the clearance of various molecules from the extracellular matrix. LRP1 also regulates cell surface expression of matrix receptors by modulating both extracellular and intracellular signals, though current knowledge of the underlying mechanisms remains partial in the frame of cancer cells interaction with matricellular substrates. In this study we identified that LRP1 downregulates calpain activity and calpain 2 transcriptional expression in an invasive thyroid carcinoma cell model. LRP1-dependent alleviation of calpain activity limits cell-matrix attachment strength and contributes to FTC133 cells invasive abilities in a modified Boyden chamber assays. In addition, using enzymatic assays and co-immunoprecipitation experiments, we demonstrated that LRP1 exerts post-translational inhibition of calpain activity through PKA-dependent phosphorylation of calpain-2. This LRP-1 dual mode of control of calpain activity fine-tunes carcinoma cell spreading. We showed that LRP1-mediated calpain inhibition participates in talin-positive focal adhesions dissolution and limits β1-integrin expression at carcinoma cell surface. In conclusion, we identified an additional and innovative intracellular mechanism which demonstrates LRP-1 pro-motile action in thyroid cancer cells. LRP-1 ability to specifically control calpain-2 expression and activity highlights a novel facet of its de-adhesion receptor status.

Pulling, failing, and adaptive mechanotransduction of macrophage filopodia

Macrophages use filopodia to withdraw particles toward the cell body for phagocytosis. This can require substantial forces, which the cell generates after bio-mechanical stimuli are transmitted to the filopodium. Adaptation mechanisms to mechanical stimuli are essential for cells, but can a cell iteratively improve filopodia pulling? If so, the underlying mechanic adaptation principles organized on the protein level are unclear. Here, we tackle this problem using optically trapped 1 μm beads, which we tracked interferometrically at 1 MHz during connection to the tips of dorsal filopodia of macrophages. We observe repetitive failures while the filopodium tries to pull the bead out of the optical trap. Analyses of mean bead motions and position fluctuations on the nano-meter and microsecond scale indicate mechanical ruptures caused by a force-dependent actin-membrane connection. We found that beads are retracted three times slower under any load between 5 and 40 pN relative to the no-load transport, which has the same speed as the actin retrograde flow obtained from fluorescent speckle tracking. From this duty ratio of pulling velocities, we estimated a continuous on/off binding with τoff = 2⋅τon, with measured off times τoff = 0.1–0.5 s. Remarkably, we see a gradual increase of filopodia pulling forces from 10 to 30 pN over time and after failures, which points toward an unknown adaptation mechanism. Additionally, we see that the attachment strength and friction between the bead and filopodium tip increases under load and over time. All observations are typical for catch-bond proteins such as integrin-talin complexes. We present a mechanistic picture of adaptive mechanotransduction, which formed by the help of mathematical models for repetitive tip ruptures and reconnections. The analytic mathematical model and the stochastic computer simulations, both based on catch-bond lifetimes, confirmed our measurements. Such catch-bond characteristics could also be important for other immune cells taking up counteracting pathogens.

A Synthetic Hydrogel Composite with a Strength and Wear Resistance Greater than Cartilage

AbstractKey hurdles for replacing damaged cartilage with an equivalent synthetic construct are the development of a hydrogel with a strength that exceeds that of cartilage and fixation of this hydrogel onto the surface of an articulating joint. This article describes the first hydrogel with a tensile and compressive strength (51 and 98 MPa) that exceeds those of cartilage (40 and 59 MPa), and the first attachment of a hydrogel to a metal backing with a shear strength (2.0 MPa) that exceeds that of cartilage on bone (1.2 MPa). The hydrogel strength is achieved through reinforcement of crystallized polyvinyl alcohol with bacterial cellulose. The high attachment strength is achieved by securing freeze‐dried bacterial cellulose to a metal backing with an adhesive and a shape memory alloy clamp prior to infiltration and crystallization of the polyvinyl alcohol. The bacterial cellulose‐reinforced polyvinyl alcohol is three times more wear resistant than cartilage over one million cycles and exhibits the same coefficient of friction. These advances in hydrogel strength and attachment enable the creation of a hydrogel‐based implant for durable resurfacing of damaged articulating joints.

Lateral force removal of fungal spores to demonstrate how surface properties affect fungal spore retention.

Microbial biofouling on polymer surfaces can lead to their biodeterioration. This may result in deterioration of the surface, leading to cracking and fracturing. Fungal spores from Aspergillus niger 1957, Aspergillus niger 1988 and Aureobasidium pullulans were tested to determine their strength of attachment on three surfaces, p(γ-MPS-co-MMA), p(γ-MPS-co-LMA) and spin-coated poly(methyl methacrylate) (PMMAsc), using lateral force measurements. The results demonstrate that A. niger 1957 and A. niger 1988 spores were most easily removed from the p(γ-MPS-co-MMA) surface, which was the surface with the highest Ra value. The A. niger 1957 and A. pullulans spores were most difficult to remove from the PMMAsc surface, which was the hardest surface. A. niger 1988 spores were the most difficult to remove from p(γ-MPS-co-LMA), the most hydrophobic surface. The results with A. pullulans were difficult to elucidate since the spores bound to all three surfaces and were removed with similar rates of force. The lateral force results demonstrate that spore attachment to a surface is a multi-factorial process, and independent surface and microbial factors influence spore binding. Thus, each environmental scenario needs to be considered on an individual basis, since a solution to one biofouling issue will probably not translate across to other systems. This article is part of the theme issue 'Nanocracks in nature and industry'.

Most frequently harboured missense variants of hACE2 across different populations exhibit varying patterns of binding interaction with spike glycoproteins of emerging SARS-CoV-2 of different lineages

Since the emergence of SARS-CoV-2 at Wuhan in the Hubei province of China in 2019, the virus has accumulated various mutations, giving rise to many variants. According to the combinations of mutations acquired, these variants are classified into lineages and greatly differ in infectivity and transmissibility. In 2021 alone, a variant of interest (VoI) Mu (B.1.621), as well as, variants of concern (VoC) Delta (B.1.617.2) and Omicron (BA.1, BA.2) and later in 2022, BA.4, BA.5, and BA.2.12.1 have emerged. Since then, the world has seen prominent surges in the rate of infection during short periods of time. However, not all populations have suffered equally, which suggests a possible role of host genetic factors. Here, we investigated the strength of binding of the spike glycoprotein receptor-binding domain (RBD) of the SARS-CoV-2 variants: Mu, Delta, Delta Plus (AY.1), Omicron sub-variants BA.1, BA.2, BA.4, BA.5, and BA.2.12.1 with the human angiotensin-converting enzyme 2 (hACE2) missense variants prevalent in major populations. In this purpose, molecular docking analysis, as well as, molecular dynamics simulation was performed of the above-mentioned SARS-CoV-2 RBD variants with the hACE2 containing the single amino acid substitutions prevalent in African (E37K), Latin American (F40L), non-Finnish European (D355 N), and South Asian (P84T) populations, in order to predict the effects of the lineage-defining mutations of the viral variants on receptor binding. The effects of these mutations on protein stability were also explored. The protein-protein docking and molecular dynamics simulation analyses have revealed variable strength of attachment and exhibited altered interactions in the case of different hACE2-RBD complexes. In vitro studies are warranted to confirm these findings which may enable early prediction regarding the risk of transmissibility of newly emerging variants across different populations in the future.

Divergent Effects of Ocean Warming On Byssal Attachment in Two Congener Mussel Species.

Organisms rely on the integrity of the structural materials they produce to maintain a broad range of processes, such as acquiring food, resisting predators or withstanding extreme environmental forces. The production and maintenance of these biomaterials, which are often modulated by environmental conditions, can therefore have important consequences for fitness in changing climates. One well-known example of such a biomaterial is mussel byssus, an array of collagen-like fibers (byssal threads) that tethers a bivalve mollusk securely to benthic marine substrates. Byssus strength directly influences mortality from dislodgement, predation or competition and depends on the quantity and quality of byssal threads produced. We compared the temperature sensitivity of byssal attachment strength of two mussel species common to the west coast of North America, Mytilus trossulus and M. galloprovincialis, when exposed to seawater temperatures ranging from 10 to 24˚C in the laboratory. We found the two species attached equally strong in seawater≤18˚C, but higher temperatures caused byssal thread production rate and quality (break force and extensibility) to be greatly reduced in M. trossulus and increased in M. galloprovincialis, leading to a 2 to 10-fold difference in overall byssus strength between the two species. Using this threshold value (18˚C), we mapped habitat for each species along the west coast of North America based on annual patterns in sea surface temperature. Estimated ranges are consistent with the current distribution of the two species and suggest a potential mechanism by which ocean warming could facilitate the northern expansion of M. galloprovincialis and displacement of native M. trossulus populations.

Attachment and Survival of Salmonella enterica and Listeria monocytogenes on Tomatoes (Solanum lycopersicum) as Affected by Relative Humidity, Temperature, and Storage Time

Tomatoes (Solanum lycopersicum) are one of the most commonly consumed fruits worldwide. The fruit can become contaminated with Salmonella and Listeria monocytogenes at various stages of the production and supply chain, and these pathogens may survive under various storage conditions. The effects of relative humidity, temperature, and duration of storage on the attachment and survival of both pathogens on the surface of tomatoes were investigated. Fresh whole Roma tomatoes were inoculated with a cocktail of Salmonella or L. monocytogenes strains and stored at 5, 12, 25, 30, or 35°C for up to 10 days. Every day during storage, relative humidity and temperature were measured and tomatoes were removed to enumerate pathogens cells that were loosely attached (LA; cells were detached from the tomato surface by rinsing) and strongly attached (SA; sonication was required to detach cells from the tomato surface). The attachment strength (SR) was calculated to express the proportion of surviving SA cells on the tomato surface. The initial levels of Salmonella and L. monocytogenes on the tomato surface after inoculation were 6.6 and 6.5 log CFU per tomato for LA cells and 5.1 and 5.6 log CFU per tomato for SA cells, respectively. For both pathogens, the LA levels were higher (P < 0.05) than the SA levels. The LA and SA levels differed significantly as a function of temperature, relative humidity, and duration of storage. The SR for Salmonella was affected by storage time but not temperature, whereas the SR for L. monocytogenes was affected by storage time and temperature and relative humidity (P < 0.05). An understanding of the attachment and survival of Salmonella and L. monocytogenes on tomatoes stored under various temperature conditions may be useful for preventing or reducing the establishment of pathogens and for designing improved decontamination methods.