Oral Secretions Research Articles

The relationship between plasma GIP and GLP-1 levels in individuals with normal and impaired glucose tolerance.

Glucose-dependent insulinotropic polypeptide (GIP) is released primarily from the proximal small intestine and glucagon-like peptide-1 (GLP-1) from the more distal small intestine and colon. Their relative importance to the incretin effect in health has been contentious in the past, although it now appears that GIP has the dominant role. It is uncertain whether there is a relationship between GIP and GLP-1 secretion. We aimed to evaluate the relationship between plasma GIP and GLP-1 responses to a 75-g oral glucose load in individuals with normal (NGT) and impaired glucose tolerance (IGT). One hundred healthy subjects had measurements of blood glucose, serum insulin, plasma GIP and GLP-1 concentrations for 240min after a 300mL drink containing 75g glucose. Fifty had NGT and 41 IGT; 9 had type 2 diabetes and were excluded from analysis. In both groups, there were increases in plasma GIP and GLP-1 following the glucose drink, with no difference in the magnitude of the responses between t = 0-240min. There was a weak relationship between the iAUC0-240min for GIP and GLP-1 in the combined (r = 0.23, P = 0.015) and in the IGT (r = 0.34, P = 0.01), but not in the NGT (r = 0.15, P = 0.14) group. There is a weak relationship between oral glucose-induced GIP and GLP-1 secretions in non-diabetic subjects.

Case report: palmar herpetic whitlow and forearm lymphangitis in a 10-year-old female

BackgroundHerpetic whitlow is a viral infection caused by the herpes simplex virus (HSV) types 1 or 2, and occurs in the pediatric population primarily on the fingers and toes due to autoinoculation from oral secretions. Because of this cited prevalence, other locations of herpetic whitlow may go unrecognized.Case presentationWe present an atypical presentation of palmar herpetic whitlow with delayed recognition and associated viral lymphangitis. The patient presented as a transfer from an outside hospital with a progressive, three-day history of a suspected left hand abscess preceded by left hand pain and itching. She was initially evaluated by Orthopedic Surgery, who described an erythematous, edematous, tender, left palmar abscess with associated erythematous streaking up her forearm. The lesion was surgically managed with an incision and drainage. Wound cultures were obtained during which “minimal drainage” was noted. After admission to the General Pediatrics Hospital service, the lesion was noted to appear vesicular and subsequently obtained PCR samples were positive for HSV type 1, confirming her diagnosis of herpetic whitlow. Although she remained afebrile with negative wound cultures throughout her hospitalization, a secondary bacterial infection could not be conclusively excluded due to the accompanying lymphangitis. Thus, she was discharged with oral antibiotics and anticipatory guidance of potential recurrence of palmar lesions.ConclusionsHerpetic whitlow should be included in the differential diagnosis of palmar lesions that appear vesicular or abscess-like to ensure appropriate treatment. Additionally, these palmar lesions may present with associated lymphangitis without evidence of bacterial infection.

Geographically isolated Colorado potato beetle mediating distinct defense responses in potato is associated with the alteration of gut microbiota

Colorado potato beetle (CPB; Leptinotarsa decemlineata) has been detected in Xinjiang, China, since 1993 and has caused serious damage to potato production during its eastward expansion to new geographic ranges. Symbiotic bacteria often play an essential role for insects to exploit novel food sources and expand into otherwise inaccessible ecological niches. An important yet unresolved question is whether herbivore populations from different geographic ranges have distinct or equal abilities to adapt to plant-induced defenses. We examined whether two geographic CPB populations collected from Urumqi and Ili varied in triggering induced defenses in potato plants, and the results demonstrated that plants damaged by Ili CPB larvae showed higher levels/activities of the defensive protein polyphenol oxidase (PPO) than those damaged by Urumqi CPB larvae. Intriguingly, application of oral secretions (OS) from Ili CPB larvae triggered higher PPO activity in potato compared with the treatments by OS collected from Urumqi larvae. Moreover, higher counts of bacterial colonies were observed in Urumqi CPB larvae by traditional culturing and quantitative PCR. Comparing the gut bacterial composition of CPB individuals by 16S rRNA amplicon sequencing also revealed higher abundance and diversity of gut-associated bacteria in the Urumqi population than that in the Ili population. These results indicate that the gut bacteria of CPB larvae were geographically shaped during the process of invasion, which played an important role in mediating plant–insect interactions and possesses a great potential to drive further invasion.

Acquisition and Development of the Extremely Preterm Infant Microbiota Across Multiple Anatomical Sites.

Microbial communities influencing health and disease are being increasingly studied in preterm neonates. There exists little data, however, detailing longitudinal microbial acquisition, especially in the most extremely preterm (<26 weeks' gestation). This study aims to characterize the development of the microbiota in this previously under-represented cohort. Seven extremely preterm infant-mother dyads (mean gestation 23.6 weeks) were recruited from a single neonatal intensive care unit. Oral and endotracheal secretions, stool, and breast milk (n = 157 total), were collected over the first 60 days of life. Targeted 16S rRNA gene sequencing identified bacterial communities present. Microbiota of all body sites were most similar immediately following birth and diverged longitudinally. Throughout the sampling period Escherichia, Enterococcus, Staphylococcus, and an Enterobacteriaceae were dominant and well dispersed across all sites. Temporal divergence of the stool from other microbiota was driven by decreasing diversity and significantly greater proportional abundance of Bifidobacteriaceae compared to other sites. Four taxa dominated all anatomical sampling sites. Rare taxa promoted dissimilarity. Cross-seeding between upstream communities and the stool was demonstrated, possibly relating to buccal colostrum/breast milk exposure and indwelling tubes. Given the importance of dysbiosis in health and disease of extremely preterm infants, better understanding of microbial acquisition within this context may be of clinical benefit.

Detection of Pepsin in Oral Secretions of Infants with and without Laryngomalacia.

Laryngomalacia is a common cause of stridor in infants and is associated with laryngopharyngeal reflux (LPR). Although pepsin in operative supraglottic lavage specimens is associated with severe laryngomalacia, detection of pepsin in oral secretions has not been demonstrated in an outpatient setting. Children <2 years old with laryngomalacia diagnosed by flexible laryngoscopy and children without stridor were selected. Oral secretion samples were obtained in clinic from all subjects. Pepsin, IL-1β, and IL-8 enzyme-linked immunosorbent assays were performed to determine presence of LPR. Sixteen laryngomalacia and sixteen controls were enrolled. Pepsin was detected more frequently in oral secretions of patients with laryngomalacia (13/16) than in controls (2/16; P < .001). Four patients with laryngomalacia developed symptoms requiring supraglottoplasty. Presence and level of salivary pepsin was not significantly associated with need for surgical management, nor were the levels or presence of IL-1β or IL-8 significantly associated with presence or level of pepsin, diagnosis of laryngomalacia, or need for operative management. Pepsin in saliva appears to be associated with laryngomalacia, suggesting a role for salivary pepsin as a noninvasive marker of LPR in patients with laryngomalacia. Future studies will determine the utility of this test in laryngomalacia.

Persistent Infection and Transmission of Senecavirus A from Carrier Sows to Contact Piglets.

Senecavirus A (SVA) is a picornavirus that causes acute vesicular disease (VD), that is clinically indistinguishable from foot-and-mouth disease (FMD), in pigs. Notably, SVA RNA has been detected in lymphoid tissues of infected animals several weeks following resolution of the clinical disease, suggesting that the virus may persist in select host tissues. Here, we investigated the occurrence of persistent SVA infection and the contribution of stressors (transportation, immunosuppression, or parturition) to acute disease and recrudescence from persistent SVA infection. Our results show that transportation stress leads to a slight increase in disease severity following infection. During persistence, transportation, immunosuppression, and parturition stressors did not lead to overt/recrudescent clinical disease, but intermittent viremia and virus shedding were detected up to day 60 postinfection (p.i.) in all treatment groups following stress stimulation. Notably, real-time PCR and in situ hybridization (ISH) assays confirmed that the tonsil harbors SVA RNA during the persistent phase of infection. Immunofluorescence assays (IFA) specific for double-stranded RNA (dsRNA) demonstrated the presence of double-stranded viral RNA in tonsillar cells. Most importantly, infectious SVA was isolated from the tonsil of two animals on day 60 p.i., confirming the occurrence of carrier animals following SVA infection. These findings were supported by the fact that contact piglets (11/44) born to persistently infected sows were infected by SVA, demonstrating successful transmission of the virus from carrier sows to contact piglets. Results here confirm the establishment of persistent infection by SVA and demonstrate successful transmission of the virus from persistently infected animals.IMPORTANCE Persistent viral infections have significant implications for disease control strategies. Previous studies demonstrated the persistence of SVA RNA in the tonsil of experimentally or naturally infected animals long after resolution of the clinical disease. Here, we showed that SVA establishes persistent infection in SVA-infected animals, with the tonsil serving as one of the sites of virus persistence. Importantly, persistently infected carrier animals shedding SVA in oral and nasal secretions or feces can serve as sources of infection to other susceptible animals, as evidenced by successful transmission of SVA from persistently infected sows to contact piglets. These findings unveil an important aspect of SVA infection biology, suggesting that persistently infected pigs may function as reservoirs for SVA.

3098 Small Plastic Objects Can Cause Foreign Body Impaction in Normal Adult Esophagus

INTRODUCTION: Foreign body impaction in the esophagus results from an inability of a swallowed object to pass through the esophagus to the stomach. In the United States, food, especially boneless meat, is the most commonly impacted foreign body. When impaction of a foreign body occurs in an adult esophagus, it usually occurs in the presence of underlying structural abnormalities (such as a web or stricture), functional abnormalities resulting from abnormal esophageal peristalsis, or when the swallowed object is too large to navigate the anatomic constrictions of the normal esophagus. This report describes two patients who had retained plastic foreign bodies in the esophagus in the presence of a normal esophageal anatomy. CASE DESCRIPTION/METHODS: Patient 1: A 39 year old man came to emergency room after accidentally swallowing a 2 cm plastic ring. He was able to swallow fluids and oral secretions, but felt a foreign body sensation in his upper chest. He denied any prior dysphagia. On endoscopy, a white plastic ring was seen in the mid-esophagus with no associated esophageal injury. Esophagus was normal with shiny mucosa. With insufflation and gentle prodding with the endoscope, the plastic ring easily passed into the stomach where it was captured using an endoscopic net and retrieved. The patient was discharged home after the procedure. Patient 2: A 53 year old woman presented to the emergency room with history of foreign body sensation and odynophagia localized to mid-chest after drinking an open cup of water. She was able to swallow water and oral secretions, but felt a sharp pain in the mid-chest every time she did so. Although she had seen a foreign body, she was convinced that she had foreign body stuck in her esophagus. Endoscopy showed a thin square piece of plastic measuring about 1 cm in size retained in a normal appearing esophagus with no obvious esophageal injury. It was retrieved using an endoscopic net. She was discharged home after the procedure. DISCUSSION: This report demonstrates that foreign bodies made of plastic can be retained in the adult esophagus in the absence of traditional risk factors. They can also present with atypical clinical features. The composition of plastic may make it more adherent to the esophageal mucosa thus preventing easy transit through the esophagus, even in the absence of restrictions in the esophagus. This report demonstrates the importance of endoscopic evaluation when a foreign body is suspected, even in the absence of a traditional presentation.

Oropharyngeal Dysphagia in Breastfeeding Neonates with Hypoxic-Ischemic Encephalopathy on Therapeutic Hypothermia.

Purpose: To identify symptoms of oropharyngeal dysphagia (OPD) in breastfeeding neonates with hypoxic-ischemic encephalopathy (HIE) on therapeutic hypothermia (TH). Early identification of feeding problems in neonates with HIE by speech-language therapists (SLTs) may prevent secondary complications of OPD such as aspiration pneumonia and death. Materials and Methods: Twenty-eight full-term neonates with HIE (mean chronological age = 4.5 days) and 30 healthy term controls were prospectively recruited for this case-control study. Participants with HIE (mild [n = 15], moderate [n = 11], severe [n = 2]), diagnosed by pediatricians, received whole-body TH. Feeding was clinically evaluated by an SLT using the Preterm Infant Breastfeeding Behavior Scale. Results: Twenty-five neonates (89.2%) had at least one symptom of OPD. Falling asleep during feeding, noticeable oral secretions, coughing, and flaring nostrils were symptoms of OPD most frequently identified. The HIE group displayed limited arousal during breastfeeding and had less obvious rooting, shallower latching onto the breast, and more single sucks in comparison to term newborns. The HIE group had significantly more closed eyes and minimal movement during breastfeeding, while controls showed the quiet-alert state ideal for breastfeeding. Conclusions: OPD was identified in the majority of infants with HIE. Underlying the appearance of an inactive neonate with HIE may be OPD that could be overlooked if not investigated. Interprofessional collaboration between SLTs, pediatricians and nurses to determine feeding-readiness is imperative. SLTs may assist in decision-making to improve safety of breastfeeding in this population. This study contributes to the small body of research on early breastfeeding of neonates with HIE.

What five insects told us about how a native plant copes with real-world problems

What five insects told us about how a native plant copes with real-world problems

SpitWorm, a Herbivorous Robot: Mechanical Leaf Wounding with Simultaneous Application of Salivary Components.

Induction of jasmonate-mediated plant defense against insect herbivory is initiated by a combination of both mechanical wounding and chemical factors. In order to study both effects independently on plant defense induction, SpitWorm, a computer-controlled device which mimics the damage pattern of feeding insect larvae on leaves and, in addition, can apply oral secretions (OS) or other solutions to the ‘biting site’ during ‘feeding,’ was developed and evaluated. The amount of OS left by a Spodoptera littoralis larva during feeding on Phaseolus lunatus (lima bean) leaves was estimated by combining larval foregut volume, biting rate, and quantification of a fluorescent dye injected into the larvae’s foregut prior to feeding. For providing OS amounts by SpitWorm equivalent to larval feeding, dilution and delivery rate were optimized. The effectiveness of SpitWorm was tested by comparing volatile organic compounds (VOC) emissions of P. lunatus leaves treated with either SpitWorm, MecWorm, or S. littoralis larvae. Identification and quantification of emitted VOCs revealed that SpitWorm induced a volatile bouquet that is qualitatively and quantitatively similar to herbivory. Additionally, RT-qPCR of four jasmonic acid responsive genes showed that SpitWorm, in contrast to MecWorm, induces the same regulation pattern as insect feeding. Thus, SpitWorm mimics insect herbivory almost identically to real larvae feeding.

Peptide and non-peptide mimetics as potential therapeutics targeting oral bacteria and oral biofilms.

The development of the oral biofilm requires a complex series of interactions between host tissues and the colonizing bacteria as well as numerous interspecies interactions between the organisms themselves. Disruption of normal host–microbe homoeostasis in the oral cavity can lead to a dysbiotic microbial community that contributes to caries or periodontal disease. A variety of approaches have been pursued to develop novel potential therapeutics that are active against the oral biofilm and/or target specific oral bacteria. The structure and function of naturally occurring antimicrobial peptides from oral tissues and secretions as well as external sources such as frog skin secretions have been exploited to develop numerous peptide mimetics and small molecule peptidomimetics that show improved antimicrobial activity, increased stability and other desirable characteristics relative to the parent peptides. In addition, a rational and minimalist approach has been developed to design small artificial peptides with amphipathic α‐helical properties that exhibit potent antibacterial activity. Furthermore, with an increased understanding of the molecular mechanisms of beneficial and/or antagonistic interspecies interactions that contribute to the formation of the oral biofilm, new potential targets for therapeutic intervention have been identified and both peptide‐based and small molecule mimetics have been developed that target these key components. Many of these mimetics have shown promising results in in vitro and pre‐clinical testing and the initial clinical evaluation of several novel compounds has demonstrated their utility in humans.

Priming and filtering of antiherbivore defences among Nicotiana attenuata plants connected by mycorrhizal networks.

Arbuscular mycorrhizal fungi (AMF) establish symbiotic associations with a majority of terrestrial plants to form underground common mycorrhizal networks (CMNs) that connect neighbouring plants. Because Nicotiana attenuata plants do not respond to herbivory-elicited volatiles from neighbours, we used this ecological model system to evaluate if CMNs function in interplant transmission of herbivory-elicited responses. A mesocosm system was designed to establish and remove CMNs linking N.attenuata plants to examine the herbivory-elicited metabolic and hormone responses in CMNs-connected "receiver" plants after the elicitation of "donor" plants by wounding (W) treated with Manduca sexta larval oral secretions (OS). AMF colonization increased constitutive jasmonate (JA and JA-Ile) levels in N.attenuata roots but did not affect well-characterized JAs-regulated defensive metabolites in systemic leaves. Interestingly, larger JAs bursts, and higher levels of several amino acids and particular sectors of hydroxygeranyllinalool diterpene glycoside metabolism were elevated in the leaves of W+OS-elicited "receivers" with CMN connections with "donors" that had been W+OS-elicited 6hr previously. Our results demonstrate that AMF colonization alone does not enhance systemic defence responses but that sectors of systemic responses in leaves can be primed by CMNs, suggesting that CMNs can transmit and even filter defence signalling among connected plants.

Meningococcal vaccines in Australia: a 2019 update.

SUMMARYInvasive meningococcal disease is a rare but serious infection caused by Neisseria meningitidisSerogroup B was the predominant serogroup causing invasive meningococcal disease in Australia until 2015. Serogroup W disease has increased substantially since 2014, and in 2017, serogroups B and W caused similar numbers of invasive disease casesVaccines against serogroups A, C, W, Y and B are available for anyone who wishes to reduce the risk of meningococcal diseaseVaccination is strongly recommended for people in high-risk age or population groups. These are children under 2 years, 15–19 year olds, Aboriginal and Torres Strait Islander children, and people with medical, occupational, behavioural or travel-related risk factors for invasive meningococcal diseaseMeningococcal ACWY vaccine is funded under the National Immunisation Program for babies aged 12 months. Since April 2019, it has been funded for year 10 students through a school program. There are additional state and territory-based programs for both meningococcal ACWY and meningococcal B vaccines

Correlation of salivary and nasal lavage pepsin with MII-pH testing.

Laryngopharyngeal reflux (LPR) is a common upper airway disease. Salivary pepsin is a proposed marker for LPR; however, the optimal time for collection of specimens for pepsin detection and pepsin's presence in the oral and nasal secretions relative to concurrent multichannel intraluminal impedance-pH (MII-pH) monitoring are unknown. Prospective case-control study with an experimental design. Patients undergoing MII-pH testing for evaluation of LPR and asymptomatic control subjects were selected. Nasal lavage and saliva samples were collected in the clinic prior to MII-pH probe placement. Additional saliva samples were obtained an hour after each meal and upon waking the following morning. Nasal lavage and salivary pepsin were measured by ELISA. Twenty-six patients undergoing MII-pH testing and 13 reflux-free control patients were enrolled. Salivary pepsin was detected in 11 of 26 patients with suspected LPR and 0 of 13 controls. Pepsin was most frequently detected in the specimen provided upon waking at an average concentration of 186.9 ng/mL. A significant correlation was observed between salivary pepsin in waking samples to MII-pH measurements, including reflux bolus duration, and proximal and distal recumbent reflux episodes (P < 0.05). A significant correlation was also observed between salivary pepsin upon waking or sinus lavage and reflux symptom index (P < 0.05). Pepsin in salivary and nasal lavage samples demonstrated an association with MII-pH-documented LPR. Pepsin detection was most frequent in morning samples, supporting use of morning salivary pepsin levels as a potential noninvasive technique for LPR diagnosis. 2 Laryngoscope, 130:961-966, 2020.

Caterpillar Chewing Vibrations Cause Changes in Plant Hormones and Volatile Emissions in Arabidopsis thaliana.

Plant perception of insect feeding involves integration of the multiple signals involved: wounding, oral secretions, and substrate borne feeding vibrations. Although plant responses to wounding and oral secretions have been studied, little is known about how signals from the rapidly transmitted vibrations caused by chewing insect feeding are integrated to produce effects on plant defenses. In this study, we examined whether 24 h of insect feeding vibrations caused changes in levels of phytohormones and volatile organic compounds (VOCs) produced by leaves of Arabidopsis thaliana when they were subjected to just feeding vibrations or feeding vibrations and wounding + methyl jasmonate (MeJA), compared to their respective controls of silent sham or wounding + MeJA. We showed that feeding vibrations alone caused a decrease in the concentrations of most phytohormones, compared to those found in control plants receiving no vibrations. When feeding vibrations were combined with wounding and application of MeJA, the results were more complex. For hormones whose levels were induced by wounding and MeJA (jasmonic acid, indole-3-butyric acid), the addition of feeding vibrations caused an even larger response. If the level of hormone was unchanged by wounding and MeJA compared with controls, then the addition of feeding vibrations had little effect. The levels of some VOCs were influenced by the treatments. Feeding vibrations alone caused an increase in β-ionone and decrease in methyl salicylate, and wounding + MeJA alone caused a decrease in benzaldehyde and methyl salicylate. When feeding vibrations were combined with wounding + MeJA, the effects on β-ionone and methyl salicylate were similar to those seen with feeding vibrations alone, and levels of benzaldehyde remained low as seen with wounding + MeJA alone. The widespread downregulation of plant hormones observed in this study is also seen in plant responses to cold, suggesting that membrane fluidity changes and/or downstream signaling may be common to both phenomena.

Current opinions about herbivore-associated molecular patterns and plant intracellular signaling

ABSTRACTElicitor-associated compounds included in oral secretions of herbivorous arthropods, defined as herbivore-associated molecular patterns (HAMPs), induce defense responses in plants. Recognition of HAMPs by the host plants triggers the activation of downstream intracellular and intercellular signaling, resulting in the production of defensive secondary metabolites and volatile emissions to defend against herbivore attack. Thus far, several chemical classes of HAMPs, e.g., fatty acid-amino acid conjugates, peptides, enzymes, and oligosaccharides, have been characterized from not only plant-chewing arthropod herbivores but also plant-sucking arthropod herbivores. Here, we introduce the latest insights about HAMPs and the HAMPs-induced defense signaling network in host plants.

Phytohormones in Fall Armyworm Saliva Modulate Defense Responses in Plants.

Insect herbivory induces plant defense responses that are often modulated by components in insect saliva, oral secretions or regurgitant, frass, or oviposition fluids. These secretions contain proteins and small molecules that act as elicitors or effectors of plant defenses. Several non-protein elicitors have been identified from insect oral secretions, whereas studies of insect saliva have focused mainly on protein identification. Yet, insect saliva may also contain non-protein molecules that could activate defense responses in plants. The goal of this study was to identify non-protein plant defense elicitors present in insect saliva. We used the fall armyworm (FAW), Spodoptera frugiperda and its host plants tomato, maize, and rice as a model system. We tested the effect of protein-digested saliva or non-protein components on herbivore-induced defense responses in maize, rice and tomato. We identified phytohormones in FAW saliva using high performance liquid chromatography coupled with mass spectrometry. The results of this study show that non-protein components in FAW saliva modulated defense responses in different plant species. The saliva of this insect contains benzoic acid, and the phytohormones jasmonic acid, salicylic acid, and abscisic acid at concentrations of <5ng per μl of saliva. Plant treatment with similar phytohormone quantities detected in FAW saliva upregulated the expression of a maize proteinase inhibitor gene in maize, and down-regulated late herbivore-induced defenses in tomato plants. We conclude that FAW saliva is a complex fluid that, in addition to known enzymatic plant defense elicitors, contains phytohormones and other small molecules.

Compensation to simulated insect leaf herbivory in wild cotton (Gossypium hirsutum): responses to multiple levels of damage and associated traits.

Identifying the mechanisms of compensation to insect herbivory remains a major challenge in plant biology and evolutionary ecology. Most previous studies have addressed plant compensatory responses to one or two levels of insect herbivory, and the underlying traits mediating such responses remain elusive in many cases. We evaluated responses associated with compensation to multiple intensities of leaf damage (0% control, 10%, 25%, 50%, 75% of leaf area removed) by means of mechanical removal of foliar tissue and application of a caterpillar (Spodoptera exigua) oral secretions in 3-month-old wild cotton plants (Gossypium hirsutum). Four weeks post-treatment, we measured plant growth and multiple traits associated with compensation, namely: changes in above- and belowground, biomass and the concentration of nutrients (nitrogen and phosphorus) and non-structural carbon reserves (starch and soluble sugars) in roots, stems and leaves. We found that wild cotton fully compensated in terms of growth and biomass allocation when leaf damage was low (10%), whereas moderate (25%) to high leaf damage in some cases led to under-compensation. Nonetheless, high levels of leaf removal (50% and 75%) in most cases did not cause further reductions in height and allocation to leaf and stem biomass relative to low and moderate damage. There were significant positive effects of leaf damage on P concentration in leaves and stems, but not roots, as well as a negative effect on soluble sugars in roots. These results indicate that wild cotton fully compensated for a low level of leaf damage but under-compensated under moderate to high leaf damage, but can nonetheless sustain growth despite increasing losses to herbivory. Such responses were possibly mediated by a re-allocation of carbohydrate reserves from roots to shoots.

A comprehensive study on nest materials of Vespa crabro and Polistes dominula: Chemical properties and biological characterization with antioxidant and antimicrobial activity

A comprehensive study was conducted on the nest materials of Vespa crabro (Linnaeus, 1758) and Polistes dominula (Christ, 1791) (Hymenoptera: Vespidae) of Black Sea region origin. Study of the physicochemical and surface properties, determination of the chemical-structural features, and bioactivity studies of the samples were carried out in four planned steps. In the first step, the physicochemical properties, the ratio of the plant material to the oral secretions, the water absorption and oil percentages as well as thermal analyses were researched. In the second step, observation of the surfaces under a light microscope and scanning electron microscope uncovered the surface properties. In the third step, chemical studies of the extracts from the solvents of different polarities (methanol, acetone and petroleum benzine) revealed the molecular functionalities of the biocompounds which were inside the materials using UV-Vis., FTIR, GC-MS, and elemental analysis techniques. In the last stage, the extracts underwent bioactivity research of antimicrobial and antioxidant screening with a phytochemical search of phenolic compound determination. The obtained data revealed the nesting properties and differences between the two species. In the P. dominula nest, the plant fibers were long and were glued regularly, and some were cross-linked and thick while in the V. crabro nest, the plant fibers were fine, grooved, thin and disordered. The comb surface of V. crabro was larger than that of P. dominula with minimum values of 75 and 37.5 cm2, respectively. The bioactivity research of the materials showed the high potential of the antimicrobial and antioxidant properties of some nests’ extracts. In all the extracts, the samples belonging to the V. crabro nest material had the highest biological activity.

Loliolide, a Carotenoid Metabolite, Is a Potential Endogenous Inducer of Herbivore Resistance.

Jasmonic acid (JA) plays an important role in the induction of herbivore resistance in many plants. However, JA-independent herbivore resistance has been suggested. An herbivore-resistance-inducing substance was isolated from Tobacco mosaic virus-infected tobacco (Nicotiana tabacum) leaves in which a hypersensitive response (HR) was induced and identified as loliolide, which has been identified as a β-carotene metabolite. When applied to tomato (Solanum lycopersicum) leaves, loliolide decreased the survival rate of the two-spotted spider mite, Tetranychus urticae, egg deposition by the same pest, and the survival rate of larvae of the common cutworm Spodoptera litura without exhibiting toxicity against these herbivores. Endogenous loliolide levels increased not only with an infestation by S litura larvae, but also with the exogenous application of their oral secretions in tomato. A microarray analysis identified cell-wall-associated defense genes as loliolide-responsive tomato genes, and exogenous JA application did not induce the expression of these genes. Suppressor of zeaxanthin-less (szl), an Arabidopsis (Arabidopsis thaliana) mutant with a point mutation in a key gene of the β-carotene metabolic pathway, exhibited the decreased accumulation of endogenous loliolide and increased susceptibility to infestation by the western flower thrip (Frankliniella occidentalis). A pretreatment with loliolide decreased susceptibility to thrips in the JA-insensitive Arabidopsis mutant coronatine-insensitive1 Exogenous loliolide did not restore reduced electrolyte leakage in szl in response to a HR-inducing bacterial strain. These results suggest that loliolide functions as an endogenous signal that mediates defense responses to herbivores, possibly independently of JA, at least in tomato and Arabidopsis plants.