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Molecular Plant-microbe Interactions :... Jan 2018Chewing herbivores, such as caterpillars and beetles, while feeding on the host plant, cause extensive tissue damage and release a wide array of cues to alter plant...
Chewing herbivores, such as caterpillars and beetles, while feeding on the host plant, cause extensive tissue damage and release a wide array of cues to alter plant defenses. Consequently, the cues can have both beneficial and detrimental impacts on the chewing herbivores. Herbivore-associated molecular patterns (HAMPs) are molecules produced by herbivorous insects that aid them to elicit plant defenses leading to impairment of insect growth, while effectors suppress plant defenses and contribute to increased susceptibility to subsequent feeding by chewing herbivores. Besides secretions that originate from glands (e.g., saliva) and fore- and midgut regions (e.g., oral secretions) of chewing herbivores, recent studies have shown that insect frass and herbivore-associated endosymbionts also play a critical role in modulating plant defenses. In this review, we provide an update on a growing body of literature that discusses the chewing insect HAMPs and effectors and the mechanisms by which they modulate host defenses. Novel "omic" approaches and availability of new tools will help researchers to move forward this discipline by identifying and characterizing novel insect HAMPs and effectors and how these herbivore-associated cues are perceived by host plant receptors.
Topics: Animals; Herbivory; Insecta; Mastication; Pathogen-Associated Molecular Pattern Molecules; Plants; Symbiosis
PubMed: 28840787
DOI: 10.1094/MPMI-07-17-0183-FI -
The Journal of Nutrition, Health & Aging 2020The aim of the study was to examine whether a combination of self-reported masticatory ability and regular dental care is linked to mortality and issuance of new...
AIM
The aim of the study was to examine whether a combination of self-reported masticatory ability and regular dental care is linked to mortality and issuance of new long-term care insurance (LTCI) service certifications.
METHODS
Older residents in institutions or in need of LTCI certification requirements were excluded, and self-administered questionnaires were sent to 5,400 older adults in 2013; these participants were followed for 5 years. The total response rate was 94.3%, and our final sample comprised 4,824 older adults (89.3%). We used 3 items to assess self-reported masticatory ability and regular dental care. These included (1) decline in chewing abilities of the posterior teeth on either side, (2) not brushing one's own teeth or dentures at least once a day, and (3) not visiting the dentist at least once a year.
RESULTS
The mean age of the participants at baseline was 75.9 years, and 58.4% of them were women. Main outcomes included mortality (n = 562) or new LTCI certification requirements (n = 1187) during the 5-year period. Multivariate analyses revealed that a poor score on masticatory ability and on regular dental care produced significant adverse health outcomes leading to earlier negative outcomes. The score is considered poor as it increases relative to the 0-point reference.
DISCUSSION
Regular dental care (both self-and professional care) and maintaining masticatory ability are both important. Hence, public activities focusing on preventive oral health from middle age onward is important.
Topics: Aged; Dental Care; Female; Humans; Male; Mastication; Mortality; Oral Health; Self Report; Surveys and Questionnaires
PubMed: 32115606
DOI: 10.1007/s12603-020-1314-7 -
Journal of Anatomy Dec 2018Cranial sutures are fibrous connective tissue articulations found between intramembranous bones of the vertebrate cranium. Growth and remodeling of these tissues is...
Cranial sutures are fibrous connective tissue articulations found between intramembranous bones of the vertebrate cranium. Growth and remodeling of these tissues is partially regulated by biomechanical loading patterns that include stresses related to chewing. Advances in oral processing structure and function of the cranium that enabled mammalian-style chewing is commonly tied to the origins and evolution of this group. To what degree masticatory overuse or underuse shapes the complexity and ossification around these articulations can be predicted based on prior experimental and comparative work. Here, we report on a mouse model system that has been used to experimentally manipulate dietary material properties in order to investigate cranial suture morphology. Experimental groups were fed diets of contrasting material properties. A masticatory overuse group was fed pelleted rodent chow, nuts with shells, and given access to cotton bedding squares. An underuse group was deprived of cotton bedding as well as diverse textured food, and instead received gelatinized food continuously. Animals were raised from weaning to adulthood on these diets, and sagittal, coronal and lambdoid suture morphology was compared between groups. Predicted intergroup variation was observed in mandibular corpus size and calvarial suture morphology, suggesting that masticatory overuse is associated with jaw and suture growth. The anterior region of the sagittal suture where it intersects with the coronal suture (bregma) showed no effect from the experiment. The posterior sagittal suture where it intersects with the lambdoid sutures (lambda) was more complex in the overuse group. In other words, the posterior calvarium was responsive to dietary material property demands while the anterior calvarium was not. This probably resulted from the different strain magnitudes and/or strain frequencies that occurred during overuse diets with diverse material properties as compared with underuse diets deprived of such enrichment. This work highlights the contrasting pattern of the sutural response to loading differences within the calvarium as a result of diet.
Topics: Animals; Biomechanical Phenomena; Cranial Sutures; Diet; Female; Mastication; Mice
PubMed: 30298923
DOI: 10.1111/joa.12888 -
Science Progress 1999The guts of people and animals function like industrial chemical plants. They are assemblies of tubes and tanks in which foods are hydrolysed by enzyme-catalysed... (Review)
Review
The guts of people and animals function like industrial chemical plants. They are assemblies of tubes and tanks in which foods are hydrolysed by enzyme-catalysed reactions, or fermented by microorganisms. Raw materials enter at one end, waste matter is voided at the other, and valuable products are abstracted on the way. A mill at the entrance end reduces the raw materials to small fragments, enabling the reactions to proceed faster. This paper shows how ideas from chemical engineering are guiding research on the gut, giving much clearer understanding of how foods respond to chewing, and of how guts are designed to process different foods. We will discuss the teeth as a grinding mill, and the digestive tube as a chain of chemical reactors.
Topics: Animals; Chemical Engineering; Digestion; Humans; Mastication; Research
PubMed: 10445010
DOI: 10.1177/003685049908200205 -
PloS One 2020The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and...
The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and temporalis muscles during mandibular tasks and habitual and non-habitual chewing in indigenous individuals to reveal the differences among white Brazilian individuals. Sixty Brazilians (18 and 28 years) were divided into two groups: 30 Xingu indigenous individuals and 30 white Brazilian individuals, with 20 men and 10 women in each group. The individuals were assessed using the normalized electromyographic activity of mandibular tasks (rest, protrusion, right and left laterality) and electromyographic activity of masticatory cycles in habitual (peanuts and raisins) and non-habitual (Parafilm M) chewing. Data were analyzed using Student's t-test (p < .05). Comparisons between the groups demonstrated significant differences. Indigenous individuals group presented a decrease in the normalized electromyographic activity of the masticatory muscles during mandibular rest [right masseter (p = .002) and left masseter (p = .004) muscles]. There was increase in the normalized electromyographic activity during protrusion [left temporal (p = .03) muscle]. There was increase in the electromyographic activity during chewing: peanuts [right masseter (p = .001), left masseter (p = .001) and right temporal (p = .01) muscles], raisins [right masseter (p = .001), left masseter (p = .002), right temporal (p = .008), left temporal (p = .01) muscles] and Parafilm M [left masseter muscle (p = .05)]. From the findings of this study, we concluded that in the comparison between indigenous and white individuals, positive changes were observed in the electromyographic pattern of the masticatory muscles in the mandibular postural conditions, with greater masticatory efficiency in the indigenous group.
Topics: Adolescent; Adult; Brazil; Electromyography; Female; Humans; Indigenous Peoples; Male; Masseter Muscle; Mastication; Temporal Muscle; Young Adult
PubMed: 33320876
DOI: 10.1371/journal.pone.0243495 -
The Angle Orthodontist Feb 2002This purpose of this study was to evaluate the largely untested assumption that malocclusion negatively affects masticatory performance. A sample of 185 untreated...
This purpose of this study was to evaluate the largely untested assumption that malocclusion negatively affects masticatory performance. A sample of 185 untreated subjects (48% male and 52% female) from 7 to 37 years of age, representing subjects with normal occlusion (n = 38), Class I (n = 56), Class II (n = 45), and Class III (n = 46) malocclusion, were evaluated. Masticatory performance was evaluated objectively using artificial (CutterSil, median particle size and broadness of the distribution) and real foods (number of chews for jerky and almonds), and subjectively using a visual analog scale. The results showed no significant differences in age or the body mass index (Wt/Ht2) between the occlusion groups. Subjects with normal occlusion had significantly smaller particle sizes (P = .001) and broader particle distributions (P < .001) than subjects with malocclusion. Compared with the normal occlusion group, the median particle sizes for the Class I, II, and III malocclusion groups were approximately 9%, 15%, and 34% larger, respectively. There were also significant group differences in their subjective ability to chew fresh carrots or celery (P = .019) and firm meat (P = .003). Class III subjects reported the greatest difficulty, followed by Class II subjects, Class I subjects, and subjects with normal occlusion, respectively. We conclude that malocclusion negatively affects subjects' ability to process and break down foods.
Topics: Adolescent; Adult; Bite Force; Body Height; Body Weight; Child; Female; Food; Hardness; Humans; Male; Malocclusion; Mastication; Particle Size; Statistics, Nonparametric; Surveys and Questionnaires
PubMed: 11843269
DOI: 10.1043/0003-3219(2002)072<0021:DMAMP>2.0.CO;2 -
International Journal of Environmental... Oct 2020Mastication plays a primary role in the process of eating. Hence, compromised masticatory ability may affect the nutrition and quality of life, which are particularly...
Mastication plays a primary role in the process of eating. Hence, compromised masticatory ability may affect the nutrition and quality of life, which are particularly important concerns among older individuals. It remains unclear how is the masticatory ability assessed regarding the nutritional status. We examined the effect of various oral factors on three masticatory ability tests conducted among older individuals. A total of 100 older individuals were enrolled in this study. Body mass index (BMI) as an indicator of nutritional status; and age, sex, and the number of occlusal and molar occlusal supports as clinical attributes were recorded. Three masticatory ability tests (masticatory efficiency, masticatory score, and satisfaction with mastication) were conducted, and tongue pressure, cheek pressure, and occlusal force were assessed as oral functions. A significant but weak correlation was found between masticatory efficiency and the masticatory score, but not between masticatory efficiency and satisfaction score. Objective masticatory efficiency was strongly associated with objective oral factors, whereas subjective assessments of masticatory ability (masticatory score and satisfaction score) were not. Furthermore, BMI was significantly associated with subjective assessments of masticatory ability but not with objective masticatory efficiency. Both subjective and objective assessments of masticatory ability, along with considerations of nutritional formulations, are required for the maintenance and improvement of nutritional status in older individuals.
Topics: Aged; Female; Humans; Male; Mastication; Nutritional Status; Pressure; Quality of Life; Tongue
PubMed: 33050275
DOI: 10.3390/ijerph17207373 -
Journal of Prosthodontic Research Jan 2024To evaluate the reproducibility and reliability of a novel electromyogram (EMG) device with a flexible sheet sensor for measuring muscle activity related to mastication...
PURPOSE
To evaluate the reproducibility and reliability of a novel electromyogram (EMG) device with a flexible sheet sensor for measuring muscle activity related to mastication and swallowing.
METHODS
We developed a new EMG device made of elastic sheet electrodes to measure the masseter and digastric muscle activities for evaluating mastication and swallowing. To examine the measurement reproducibility of the new EMG device, masseter muscle activity was analyzed using the intraclass correlation coefficient (ICC). Further, we measured the maximum amplitude, duration, integrated value, and signal-to-noise ratio (SNR) using the new EMG device and conventional EMG devices and evaluated the reliability using ICC and Bland-Altman analysis.
RESULTS
We confirmed high ICC (1,1) and ICC (2,1) scores (0.92 and 0.88, respectively) while measuring the reproducibility of the new EMG device. When compared to the active electrode EMG device, we found a high correlation for the maximum amplitude (0.90), duration (0.99), integrated values (0.90), and SNR (0.75), with no observation of significant fixed errors. Moreover, the regression coefficient was not significant for any of the evaluation items and no proportional error was observed. Compared with the passive electrode EMG device, the maximum amplitude and duration were highly correlated (0.73 and 0.89). In addition, the SNR exhibited a significant fixed error. In contrast, the regression coefficient was not significant for any of the evaluation items and no proportional error was observed.
CONCLUSIONS
Our results suggest that the new EMG device can be used to reliably and reproducibly evaluate muscle activity during mastication and swallowing.
Topics: Masseter Muscle; Electromyography; Reproducibility of Results; Mastication; Electrodes
PubMed: 37197948
DOI: 10.2186/jpr.JPR_D_22_00239 -
Journal of Oral Science Jan 2023The study aimed to examine the association of self-rated chewing function, the number of teeth and periodontal status with metabolic syndrome.
PURPOSE
The study aimed to examine the association of self-rated chewing function, the number of teeth and periodontal status with metabolic syndrome.
METHODS
The participants were 11,119 adults aged 40-74 years who underwent specific health checkups, including an oral health examination, in 2018 in Japan. This study used the standard questions of the specific health checkups to obtain information on self-rated chewing function. A multinomial logistic regression analysis was performed with metabolic syndrome status as the dependent variable, and age, sex, lifestyle questions, self-rated chewing function, number of teeth, and periodontal status as the independent variables.
RESULTS
Number of teeth and periodontal status were significantly associated with metabolic syndrome after adjusting for confounding variables. Self-rated chewing function was significantly associated with metabolic syndrome in the crude analysis, but not after adjustment for confounding variables. Both number of teeth and periodontal status were significantly associated with self-rated chewing function.
CONCLUSION
There was no significant direct association between self-rated chewing function and metabolic syndrome. Self-rated chewing function may be an indicator of poor oral condition that links to metabolic syndrome.
Topics: Adult; Humans; Health Status; Mastication; Metabolic Syndrome; Mouth Diseases; Oral Health; Tooth
PubMed: 36529512
DOI: 10.2334/josnusd.22-0229 -
Anatomical Record (Hoboken, N.J. : 2007) Dec 2016Mammalian zygomatic arch shape is remarkably variable, ranging from nearly cylindrical to blade-like in cross section. Based on geometry, the arch can be hypothesized to...
Mammalian zygomatic arch shape is remarkably variable, ranging from nearly cylindrical to blade-like in cross section. Based on geometry, the arch can be hypothesized to be a sub-structural beam whose ability to resist deformation is related to cross sectional shape. We expect zygomatic arches with different cross sectional shapes to vary in the degree to which they resist local bending and torsion due to the contraction of the masseter muscle. A stiffer arch may lead to an increase in the relative proportion of applied muscle load being transmitted through the arch to other cranial regions, resulting in elevated cranial stress (and thus, strain). Here, we examine the mechanics of the zygomatic arch using a series of finite element modeling experiments in which the cross section of the arch of Pan troglodytes has been modified to conform to idealized shapes (cylindrical, elliptical, blade-like). We find that the shape of the zygomatic arch has local effects on stain that do not conform to beam theory. One exception is that possessing a blade-like arch leads to elevated strains at the postorbital zygomatic junction and just below the orbits. Furthermore, although modeling the arch as solid cortical bone did not have the effect of elevating strains in other parts of the face, as had been expected, it does have a small effect on stress associated with masseter contraction. These results are counterintuitive. Even though the arch has simple beam-like geometry, we fail to find a simple mechanical explanation for the diversity of arch shape. Anat Rec, 299:1734-1752, 2016. © 2016 Wiley Periodicals, Inc.
Topics: Animals; Biomechanical Phenomena; Finite Element Analysis; Mastication; Pan troglodytes; Skull; Stress, Mechanical; Zygoma
PubMed: 27870343
DOI: 10.1002/ar.23484