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Intercellular protuberances (IPs) are projections on the cell surface and have been reported for families of ferns, Gymnosperms, and Angiosperms. Data on the type, chemical composition, and distribution of these structures among vascular plants are still scarce. Here, we investigate the occurrence, distribution, type of IPs among species of eight Dennstaedtiaceae genera and verify the taxonomic significance of these protuberances in the family. Rhizomes of 23 species of Dennstaedtiaceae from field and herbaria collections were analyzed by light microscopy and scanning electron microscopy. Histochemical tests were performed to identify the main classes of IPs chemical compounds. Two types of IPs were observed in Dennstaedtiaceae species: strand and filament types. They were observed in the intercellular spaces of the parenchyma in the cortex and pith regions. Overall, protuberances are irregularly shaped, with angustate or spheroidal apices. Their polysaccharide nature and pectic constitution were confirmed by histochemical tests. Concerning Pteridium arachnoideum (Kaulf.) Maxon subsp. arachnoideum, IPs have confirmed phenolic composition. Evidence indicates that IPs in Dennstaedtiaceae originate from the fragmentation of the middle lamella and that they have a structural function as well as protection against pathogens. In lateral-line aerenchyma, the occurrence of filament-type IPs may be related to the larger intercellular spacing in the cortex region, providing greater mechanical resistance. We have expanded the data on the occurrence of IPs in the Dennstaedtiaceae, which appear to be notable characters for the family. Moreover, the data presented herein confirmed the polysaccharide and pectic nature of these structures. However, we were unable to find links between IPs and taxonomy and evolution of the Dennstaedtiaceae. On the other hand, different IPs types were identified between the clades Dennstaedtioideae (strand-type IPs) and Hypolepidoideae (filament-type IPs, with exceptions).

Intercellular protuberances (IPs) are projections on the cell surface and have been reported for families of ferns, Gymnosperms, and Angiosperms. Data on the type, chemical composition, and distribution of these structures among vascular plants are still scarce. Here, we investigate the occurrence, distribution, type of IPs among species of eight Dennstaedtiaceae genera and verify the taxonomic significance of these protuberances in the family. Rhizomes of 23 species of Dennstaedtiaceae from field and herbaria collections were analyzed by light microscopy and scanning electron microscopy. Histochemical tests were performed to identify the main classes of IPs chemical compounds. Two types of IPs were observed in Dennstaedtiaceae species: strand and filament types. They were observed in the intercellular spaces of the parenchyma in the cortex and pith regions. Overall, protuberances are irregularly shaped, with angustate or spheroidal apices. Their polysaccharide nature and pectic constitution were confirmed by histochemical tests. Concerning Pteridium arachnoideum (Kaulf.) Maxon subsp. arachnoideum, IPs have confirmed phenolic composition. Evidence indicates that IPs in Dennstaedtiaceae originate from the fragmentation of the middle lamella and that they have a structural function as well as protection against pathogens. In lateral-line aerenchyma, the occurrence of filament-type IPs may be related to the larger intercellular spacing in the cortex region, providing greater mechanical resistance. We have expanded the data on the occurrence of IPs in the Dennstaedtiaceae, which appear to be notable characters for the family. Moreover, the data presented herein confirmed the polysaccharide and pectic nature of these structures. However, we were unable to find links between IPs and taxonomy and evolution of the Dennstaedtiaceae. On the other hand, different IPs types were identified between the clades Dennstaedtioideae (strand-type IPs) and Hypolepidoideae (filament-type IPs, with exceptions). [ABSTRACT FROM AUTHOR]

This study aims to explore the shrinkage of onion cells, single and multi-layer onion section, and expansion of intercellular pathways during dehydration. For macro and bulk-level studies, moisture analyzer and hot air convective dryer were used, respectively. Shrinkage, size retention, and color changes due to dehydration and rehydration of onion shreds were compared. At micro-level, CaCl2 and water blanched samples dehydrated at 70 °C, citric acid blanched samples dehydrated at 60 and 80 °C showed less shrinkage compared to unblanched samples. On rehydration, single layer section showed comparable cell size and intercellular space retention. Multi-layer section of CaCl2 blanched samples dehydrated at 70 °C retained better structure. At macro-level dehydration, shrinkage of CaCl2 blanched samples was the least. At bulk-level, all blanched samples shrank by 82–90%. Bulk level rehydration at 50 °C achieved better size retention. Blanching resulted a porous structure of onion shreds with an improved rehydration characteristics. [ABSTRACT FROM AUTHOR]

After the new molecular-based classification was reported to be useful for predicting prognosis, the T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign has gained interest as one of the promising methods for detecting lower grade gliomas (LGGs) with isocitrate dehydrogenase (IDH) mutations and chromosome 1p/19q non-codeletion (IDH mut-Noncodel) with high specificity. Although all institutions could use T2-FLAIR mismatch sign without any obstacles, this sign was not completely helpful because of its low sensitivity. In this study, we attempted to uncover the mechanism of T2-FLAIR mismatch sign for clarifying the cause of this sign's low sensitivity. Among 99 patients with LGGs, 22 were T2-FLAIR mismatch sign-positive (22%), and this sign as a marker of IDH mut-Noncodel showed a sensitivity of 55.6% and specificity of 96.8%. Via pathological analyses, we could provide evidence that not only microcystic changes but the enlarged intercellular space was associated with T2-FLAIR mismatch sign (p = 0.017). As per the molecular analyses, overexpression of mTOR-related genes (m-TOR, RICTOR) were detected as the molecular events correlated with T2-FLAIR mismatch sign (p = 0.020, 0.030. respectively). Taken together, we suggested that T2-FLAIR mismatch sign could pick up the IDH mut-Noncodel LGGs with enlarged intercellular space or that with overexpression of mTOR-related genes. [ABSTRACT FROM AUTHOR]

Abstract Some species of Diospyros form the black wood that is known as ebony. Infrequently, D. kaki forms wood with black patterning that is called “kurogaki” in Japan and is highly valued. To understand the mechanism of formation of the blackened xylem, we attempted to clarify the pathways of diffusion of colored substances from the site of their biosynthesis to their deposition in secondary xylem. We observed colored substances in pits and intercellular spaces and we recorded the deposition of colored substances in the cell walls of wood fibers. In gray and black regions, we found colored substances in the pits between xylem cells, in blind pits and in intercellular spaces. At the boundary between whitish and black regions, areas of coloration in the cell walls of wood fibers gradually increased in size from the whitish to the black regions. Heavy deposition of colored substances was observed in the inner region of the secondary walls of wood fibers. Furthermore, coloration of the outer region of the secondary walls and compound middle lamella (CML) of wood fibers gradually became stronger toward the black regions. Our observations suggest that pit-pairs and intercellular spaces might provide the pathways for inter- and extracellular diffusion of colored substances, respectively. In addition, colored substances might penetrate the cell walls of wood fibers, moving from the lumen into the cell wall.

Understanding the biomechanical phenomena governing the intercellular space can be considered as an effective tool for the treatment of tumors and cancerous tissues. One of the factors that plays a significant role in the quality and efficiency of the drug delivery process to tumors and cancerous tissues as one of the influential biomechanical factors is the osmotic pressure in the interstitial fluid in the intercellular space of tumors. In this study, the effect of osmotic pressure on the distribution of stress and strain in a tumor tissue is investigated in two modes using a poro-elastic and two-dimensional model. The results of this study show that the effect of osmotic pressure and change in the circumference of tumor tissue causes a decrease or increase in mechanical stress and strain, which can be used to control the tumor growth for treatment. In fact, according to the results, by isolating the tumor tissue (This refers to a condition in which tumor cells have grown in rigid containers) and considering the osmotic pressure, the stress created in the tissue is reduced, but if the tumor tissue is surrounded by healthy tissue and osmotic pressure is applied to it, the stress to increase by about 30 Pa compared to when these two assumptions are not considered. [ABSTRACT FROM AUTHOR]

Phytomelanin is a brown to black pigment found in plant tissues, mainly in Asparagales and Asteraceae species. However, few studies deal with the processes of its synthesis, and there are still many questions to be answered regarding the organelles involved in this process and their functions, especially in vegetative organs. In a previous study with stems and leaves of 77 Vernonieae (Asteraceae) species, phytomelanin was demonstrated to always be associated with sclereids, which suggests the involvement of these cells in the pigment synthesis. Thus, we selected another species of tribe Vernonieae, Piptocarpha axillaris (Less.) Baker, which produces abundant phytomelanin secretion in stem tissues, to investigate which cells and organelles are involved in the synthesis and release of this pigment, as well as its distribution in the tissues. To achieve this goal, stems in different developmental phases were analyzed under light and transmission electron microscopy. Anatomical analysis showed that the polymerization of phytomelanin in P. axillaris starts at the second stem node, in the pith region, and occurs simultaneously with sclereid differentiation. The plastids of cells that will differentiate into sclereids actively participate in the phenolic material synthesis, following the "tannosome" and the "pearl necklace" models, giving rise to the main precursor of phytomelanin, which is then polymerized in the intercellular spaces during the sclerification process of sclereids. In stems with an established secondary structure, the pigment can be observed more frequently in the cortex, pericycle, primary phloem, secondary phloem, and pith. [ABSTRACT FROM AUTHOR]

Because stomata in bryophytes are uniquely located on sporangia, the physiological and evolutionary constraints placed on bryophyte stomata are fundamentally different from those on leaves of tracheophytes. Although losses of stomata have been documented in mosses, the extent to which this evolutionary process occurred remains relatively unexplored. We initiated this study by plotting the known occurrences of stomata loss and numbers per capsule on the most recent moss phylogeny. From this, we identified 40 families and 74 genera that lack stomata, of which at least 63 are independent losses. No trends in stomata losses or numbers are evident in any direction across moss diversity. Extant taxa in early divergent moss lineages either lack stomata or produce pseudostomata that do not form pores. The earliest land plant macrofossils from 400 ma exhibit similar sporangial morphologies and stomatal distribution to extant mosses, suggesting that the earliest mosses may have possessed and lost stomata as is common in the group. To understand why stomata are expendable in mosses, we conducted comparative anatomical studies on a range of mosses with and without stomata. We compared the anatomy of stomate and astomate taxa and the development of intercellular spaces, including substomatal cavities, across mosses. Two types of intercellular spaces that develop differently are seen in peristomate mosses, those associated with stomata and those that surround the spore sac. Capsule architecture in astomate mosses ranges from solid in the taxa in early divergent lineages to containing an internal space that is directly connected to the conducing tissue and is involved in capsule expansion and the nourishment, hydration and development of spores. This anatomy reveals there are different architectural arrangements of tissues within moss capsules that are equally effective in accomplishing the essential processes of sporogenesis and spore dispersal. Stomata are not foundational to these processes.

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Some species of Diospyros form the black wood that is known as ebony. Infrequently, D. kaki forms wood with black patterning that is called "kurogaki" in Japan and is highly valued. To understand the mechanism of formation of the blackened xylem, we attempted to clarify the pathways of diffusion of colored substances from the site of their biosynthesis to their deposition in secondary xylem. We observed colored substances in pits and intercellular spaces and we recorded the deposition of colored substances in the cell walls of wood fibers. In gray and black regions, we found colored substances in the pits between xylem cells, in blind pits and in intercellular spaces. At the boundary between whitish and black regions, areas of coloration in the cell walls of wood fibers gradually increased in size from the whitish to the black regions. Heavy deposition of colored substances was observed in the inner region of the secondary walls of wood fibers. Furthermore, coloration of the outer region of the secondary walls and compound middle lamella (CML) of wood fibers gradually became stronger toward the black regions. Our observations suggest that pit-pairs and intercellular spaces might provide the pathways for inter- and extracellular diffusion of colored substances, respectively. In addition, colored substances might penetrate the cell walls of wood fibers, moving from the lumen into the cell wall. [ABSTRACT FROM AUTHOR]

Because stomata in bryophytes are uniquely located on sporangia, the physiological and evolutionary constraints placed on bryophyte stomata are fundamentally different from those on leaves of tracheophytes. Although losses of stomata have been documented in mosses, the extent to which this evolutionary process occurred remains relatively unexplored. We initiated this study by plotting the known occurrences of stomata loss and numbers per capsule on the most recent moss phylogeny. From this, we identified 40 families and 74 genera that lack stomata, of which at least 63 are independent losses. No trends in stomata losses or numbers are evident in any direction across moss diversity. Extant taxa in early divergent moss lineages either lack stomata or produce pseudostomata that do not form pores. The earliest land plant macrofossils from 400 ma exhibit similar sporangial morphologies and stomatal distribution to extant mosses, suggesting that the earliest mosses may have possessed and lost stomata as is common in the group. To understand why stomata are expendable in mosses, we conducted comparative anatomical studies on a range of mosses with and without stomata. We compared the anatomy of stomate and astomate taxa and the development of intercellular spaces, including substomatal cavities, across mosses. Two types of intercellular spaces that develop differently are seen in peristomate mosses, those associated with stomata and those that surround the spore sac. Capsule architecture in astomate mosses ranges from solid in the taxa in early divergent lineages to containing an internal space that is directly connected to the conducing tissue and is involved in capsule expansion and the nourishment, hydration and development of spores. This anatomy reveals there are different architectural arrangements of tissues within moss capsules that are equally effective in accomplishing the essential processes of sporogenesis and spore dispersal. Stomata are not foundational to these processes. [ABSTRACT FROM AUTHOR]

• Zebrafish larval bones are labelled within minutes by dyes injected into the blood. • In the tail fin there is a direct intercellular connection between artery and bone. • An intercellular continuous space connects also between the vein and forming bone. • The intercellular space creates fast route for material transport from blood to bone. The pathway of ion supply from the source to the site of bone deposition in vertebrates is thought to involve transport through the vasculature, followed by ion concentration in osteoblasts. The cells deposit a precursor mineral phase in vesicles, which are then exocytosed into the extracellular matrix. We observed that the entire skeleton of zebrafish larvae, is labelled within minutes after injection of calcein or FITC-dextran into the blood. This raised the possibility that there is an additional pathway of solute transport that can account for the rapid labelling. We used cryo-FIB-SEM serial block face imaging to reconstruct at high resolution the 3D ultrastructure of the caudal tail of the zebrafish larva. This reconstruction clearly shows that there is a continuous intercellular pathway from the artery to the forming bone, and from the forming bone to the vein. Fluorescence light microscopy shows that calcein and FITC-dextran form a reticulate network pattern in this tissue, which we attribute to the dye being present in the intercellular space. We conclude that this intercellular continuous space may be a supply route for ions, mineral and other solute or particulate material to the fast forming bone. [ABSTRACT FROM AUTHOR]

Background/Purpose: Skin care via moisturization compensates for the lack of skin barrier function. However, moisturizer application methods are not clearly decided. Here, we focused on and examined the retention of externally applied ceramide in the stratum corneum (SC) using fluorescent imaging method. This study aimed to compare ceramide retention in the SC between normal skin and dry skin using an animal model. Methods: Nine‐week‐old Sprague‐Dawley rats were divided into two groups: normal skin and dry skin model. The dry skin model group was treated with acetone‐diethyl ether solution. A fluorescently labeled ceramide solution was prepared and applied to rats' back skin. Skin samples were taken at 0 minute and 12 hours after ceramide application. Fluorescently labeled ceramide was evaluated and observed under a microscope. Results: The intensity of externally applied ceramide in the normal skin group showed no significant change from 0 minute to 12 hours after application. In contrast, in the dry skin model group, the intensity of externally applied ceramide increased significantly from 0 minute to 12 hours after application. Conclusion: Our findings demonstrate that the externally applied ceramide penetrated the SC of dry skin more than that of normal skin. [ABSTRACT FROM AUTHOR]

Aquaporin-8 (AQP8) is a water channel protein expressed exclusively in granulosa cells (GCs) in mouse ovary. Our previous studies of AQP8-deficient (AQP8-/-) mice demonstrated that AQP8 participates in folliculogenesis, including in the formation of follicles, ovulation, and atresia. However, its physiological function in formation of the antral follicle is still largely unknown. In the present study, we observed significantly increased numbers of antral follicles in AQP8-/- ovaries as well as significantly increased follicular antrum formation in in vitro 3D culture of AQP8-/- follicles. Functional detection of AQP8-/- GCs indicated that cell proliferation is impaired with FSH treatment, and wound healing and Transwell migration are also impaired with or without FSH treatment, compared with that in WT. However, the biosynthesis of estradiol and progesterone as well as the mRNA levels of key steroidogenic enzyme genes (CYP19A1 and StAR) in AQP8-/- GCs did not change, even with addition of FSH and/or testosterone. In order to estimate the influence of the impaired proliferation and migration on the density of GC mass, preantral follicles were injected with FITC-dextran, which distributes only in the intercellular space, and analyzed by confocal microscopy. The micrographs showed significantly higher transmission of fluorescence in AQP8-/- follicles, suggesting increased intercellular space of GCs. Based on this evidence, we concluded that AQP8 deficiency leads to increased formation of follicular antra in vivo and in vitro , and the mechanism may be associated with increased intercellular space of GCs, which may be caused by defective proliferation and migration of GCs. This study may offer new insight into the molecular mechanisms of the formation of follicular antrum. [ABSTRACT FROM AUTHOR]

The persistence of a mangrove ecosystem depends on the potential of its propagules to disperse. In case of the Rhizophoraceae mangrove species, propagules are elongated cylinder-shaped seedlings that have an initial ability to float upon abscission from the parent tree. During the hydrochoric dispersal period, propagule traits ( e.g. volume and density) change over time, which in parallel influences propagule buoyancy behaviour. Recently abscised, mature propagules of three rhizophoracean mangrove species ( Bruguiera gymnorrhiza (L.) Sav., Ceriops tagal (Perr.) C.B. Rob., Rhizophora mucronata Lam.) were submitted to a three-month floating experiment to investigate the timing and pattern in their buoyancy behaviour linked to changes in propagule density. Anatomical analyses of the aerenchymatous tissues complemented the floatation data. Initial propagule density (between 0.96 ( C. tagal ) and 0.99 g cm −3 ( B. gymnorrhiza and R. mucronata )) was on slightly lower than that of seawater and increased over time in all species but at dissimilar rates. Intra-individual density increased from the plumule- towards the radicle end, and corresponded with a decrease in proportion of intercellular surface area per unit area. The interplay between propagule traits and surface water conditions determine the fate of each propagule and its capacity to escape the local forest and reach open water. The combination of techniques used and hence combination of data obtained in this study, contribute to an increased understanding of mangrove forest dynamics: the potential and the limits therein to expand the species range or to replenish existing populations with new recruits. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare esophageal infusion with 0.1 N hydrochloridric acid (HCl) to esophageal infusion with saline in patients presenting with typical gastroesophageal reflux symptoms and erosive esophagitis. METHODS: Upper gastrointestinal endoscopy was performed on 44 prospective subjects, 29 of whom were included in the study. Eighteen patients presented with normal esophagi (Control Group "C"), nine of whom were infused with HCl and nine with saline. Eleven patients presented with erosive esophagitis (Lesion Group "L"), five of whom were infused with HCl and six with saline. Biopsies of the esophageal mucosa were collected before and after infusions. RESULTS: No statistically significant difference was found between the two types of infusions in terms of the dilation of the intercellular space of the esophageal epithelium, regardless of the status of the patient. CONCLUSIONS: Response to HCl infusion cannot be used as a marker for gastroesophageal reflux disease.

The objective of this study was to investigate the anatomical causes of the softening of Wonhwang oriental pear by digitizing changes in cell size and intercellular space (IS). We attempted to identify differences affected by growth stage, storage conditions, and harvest timing. Fruit softening was a process caused by changes in cell size, IS widening, and the breaking of cell wall concatenation. Fruits in the growth stage were softened primarily by cell expansion and subsequent widening of the IS. For fruits stored at room temperature, softening proceeded very rapidly; the reason underlying rapid softening appeared to be the empty spaces created by cell wall destruction. For fruits stored at low temperature, rapid softening caused by the destruction of cell walls was delayed, but the fruits softened continually due to IS widening. Furthermore, cell size exhibited a positive correlation with firmness, which caused IS widening and softening of the fruits due to cell contraction. Thus, decreased cell size and widened IS caused softening under low-temperature conditions, and the relationship between softening and cell size was different than that observed during the growth stage. [ABSTRACT FROM AUTHOR]

Organisms are constantly exposed to environmental stimuli and have evolved mechanisms of protection and adaptation. Various effects of nanoparticles (NPs) on crops have been described and some results confirm that NPs could enhance plant growth at the physiological and genetic levels. This study comparatively analysed the effect of carbon nanotubes (CNTs) on rice growth. The results showed that single‐wall CNTs were located in the intercellular space while multi‐wall CNTs penetrated cell walls in roots. CNTs could promote rice root growth through the regulation of expression of the root growth related genes and elevated global histone acetylation in rice root meristem zones. These responses were returned to normal levels after CNTs were removed from medium. CNTs caused the similar histone acetylation and methylation statuses across the local promoter region of the Cullin‐RING ligases 1 (CRL1) gene and increased micrococcal nuclease accessibility of this region, which enhanced this gene expression. The authors results suggested that CNTs could cause plant responses at the cellular, genetic, and epigenetic levels and these responses were independent on interaction modes between root cells and CNTs. [ABSTRACT FROM AUTHOR]

Background and Aims When the orientation of the stems of conifers departs from the vertical as a result of environmental influences, conifers form compression wood that results in restoration of verticality. It is well known that intercellular spaces are formed between tracheids in compression wood, but the function of these spaces remains to be clarified. In the present study, we evaluated the impact of these spaces in artificially induced compression wood in Chamaecyparis obtusa seedlings. Methods We monitored the presence or absence of liquid in the intercellular spaces of differentiating xylem by cryo-scanning electron microscopy. In addition, we analysed the relationship between intercellular spaces and the hydraulic properties of the compression wood. Key Results Initially, we detected small intercellular spaces with liquid in regions in which the profiles of tracheids were not rounded in transverse surfaces, indicating that the intercellular spaces had originally contained no gases. In the regions where tracheids had formed secondary walls, we found that some intercellular spaces had lost their liquid. Cavitation of intercellular spaces would affect hydraulic conductivity as a consequence of the induction of cavitation in neighbouring tracheids. Conclusions Our observations suggest that cavitation of intercellular spaces is the critical event that affects not only the functions of intercellular spaces but also the hydraulic properties of compression wood. [ABSTRACT FROM AUTHOR]

The routine diagnostic procedure of actinic keratosis (AK) and invasive squamous cell carcinoma (SCC) is a histological examination after taking a biopsy. In the past decades, non-invasive optical methods for skin examination have been developed. Patients with clinical diagnosis of AK or SCC were examined. The morphological criteria were determined for healthy, AK and SCC skin and compared for statistically significant differences. In this study, the applicability of multiphoton tomography (MPT) as an in vivo diagnostic tool for AK and SCC was evaluated. Changes in the morphology of the keratinocytes such as broadened epidermis, large intercellular spaces, enlarged nucleus and a large variance in cell shape could easily be recognized. The cell nuclei of AK and SCC were significantly larger compared to healthy skin cells in all cell layers. The nucleus-cytoplasm ratio was also significantly higher for AK and SCC than for the healthy skin cells. It was even higher in SCC compared to spinous and basal cell layer of AK. The cell density in AK and SCC was significantly lower than in the basal and spinous cell layers of healthy skin. In SCC, the cell density was significantly lower than in AK. Concerning the intercellular spaces, significant differences were found for AK and healthy skin in spinous and basal cell layer and for SCC compared to AK and healthy skin. In this study, MPT proved to be a valuable non-invasive imaging method for in vivo detection and discrimination of AK and SCC from healthy skin. [ABSTRACT FROM AUTHOR]

Mansoo is a russet pear cultivar cultivated in Korea and susceptible to cracking at maturity. Cracked regions were studied using light (LM), stereo (SM), and scanning electron microscopy (SEM) to compare the prevalence of this phenomenon in Mansoo and Niitaka cultivars. The initial cracking stage was observed as a short-length-shaped crack (SLSC) on the lenticel, followed by an enlargement and extension of the cracked region as a long-length-shaped crack (LLSC). Although the cracked region on the lenticel was discovered with the naked eye, cracking also occurred in the surrounding filling tissue region, which has a thin hypodermis because of a crevice of cork tissue. The cracking occurred in the intercellular space of parenchymal tissue and between stone cell clusters. Mansoo fruit has thinner, more irregular, and less numerous hypodermis layers than that of Niitaka. Stone cell clusters in the peripheral parenchyma were concentrated because they were larger and had a smaller distance between them in Mansoo cultivars than in Niitaka. These results demonstrate that the morphological and anatomical features observed in Mansoo fruit are cracking susceptibility factors. [ABSTRACT FROM AUTHOR]

In Arabidopsis, much of what we know about the phytohormone salicylic acid (SA) and its role in plant defense comes from experiments using young plants. We are interested in understanding why young plants are susceptible to virulent strains of Pseudomonas syringae, while mature plants exhibit a robust defense response known as age-related resistance (ARR). SA-mediated signaling is important for defense in young plants, however, ARR occurs independently of the defense regulators NPR1 and WHY1. Furthermore, intercellular SA accumulation is an important component of ARR, and intercellular washing fluids from ARR-competent plants exhibit antibacterial activity, suggesting that SA acts as an antimicrobial agent in the intercellular space. Young plants accumulate both intracellular and intercellular SA during PAMP- and effector-triggered immunity, however, virulent P. syringae promotes susceptibility by suppressing SA accumulation using the phytotoxin coronatine. Here we outline the hypothesis that mature, ARR-competent Arabidopsis alleviates coronatine-mediated suppression of SA accumulation. We also explore the role of SA in other mature-plant processes such as flowering and senescence, and discuss their potential impact on ARR. [ABSTRACT FROM AUTHOR]

The extracellular space (ECS or apoplast) is the plant cell compartment external to the plasma membrane, which includes the cell walls, the intercellular space and the apoplastic fluid (APF). The present review is focused on APF proteomics papers and intends to draw information on the metabolic processes occurring in the ECS under abiotic and biotic stresses, as well as under non-challenged conditions. The large majority of the proteins detected are involved in “cell wall organization and biogenesis”, “response to stimulus” and “protein metabolism”. It becomes apparent that some proteins are always detected, irrespective of the experimental conditions, although with different relative contribution. This fact suggests that non-challenged plants have intrinsic constitutive metabolic processes of stress/defense in the ECS. In addition to the multiple functions ascribed to the ECS proteins, should be considered the interactions established between themselves and with the plasma membrane and its components. These interactions are crucial in connecting exterior and interior of the cell, and even simple protein actions in the ECS can have profound effects on plant performance. The proteins of the ECS are permanently contributing to the high dynamic nature of this plant compartment, which seems fundamental to plant development and adaptation to the environmental conditions.

To characterize leaf cell wall proteins relating the architectural changes of leaves, we analyzed Nicotiana tabacum leaf cell wall proteins that were extracted by the treatment with lithium chloride. Some of these proteins showed amino acid sequence homology to some germin-like proteins (GLP). Based of those sequences, we isolated the cDNA encoding the GLPs (NtGLP1-1, NtGLP2-1). Phylogenetic analysis including de novo assembled tobacco GLPs using EST clones, revealed that tobacco GLPs belong to at least 5 different subgroups of GLP and both NtGLP1 and NtGLP2 belong to GLP subfamily 3. We showed that the NtGLP1 actually localizes to cell wall and revealed that it predominantly localized at specific sites on the leaf cell wall where intercellular attachment was just bifurcated. Expression of the NtGLP1 mRNA was mainly detected in leaves especially at elongating stage. NtGLP1 is possibly relevant to development of leaf intercellular space. [ABSTRACT FROM AUTHOR]

The aim of this study was to demonstrate the presence of intraepithelial stroma represented by extracellular matrix (ECM) deposits in the junctional epithelium to clarify its function as a scaffold for leukocyte migration through epithelial cells. Twenty-three biopsy specimens from the gingiva including the junctional epithelium were examined to determine comparative protein and gene level expression profiles for keratin and ECM molecules between the junctional epithelium and the gingival epithelium using immunohistochemistry and in situ hybridization. Intraepithelial leukocyte types and frequencies were also determined and compared between the junctional and gingival epithelia. In the junctional epithelium, which was positive for keratin 19, perlecan was strongly deposited in intercellular space of the whole epithelial layer, while it was faintly positive around the parabasal layer of the gingival epithelium. Perlecan mRNA signals were enhanced to a greater degree in both epithelial and inflammatory cells within the junctional epithelium. In the junctional epithelium, greater numbers of neutrophils and macrophages were found as compared with the gingival epithelium. Our results showed that perlecan is the primary ECM molecule comprising intraepithelial stroma of the junctional epithelium, in which leukocytes may migrate on ECM scaffolds in intercellular space toward the surface of the gingival sulci or pockets. [ABSTRACT FROM AUTHOR]

Objective To assess the performance of self-assessment gastroesophageal reflux disease questionnaire ( GerdQ), 24-h impedance monitoring, proton pump inhibitor ( PPI) test and intercellular space of esophageal mucosal epithelial cells in the diagnosis of gastroesophageal reflux disease ( GERD). Methods Patients with symptoms suspected of GERD were administered the GerdQ and underwent endoscopy (measurement of intercellular space in the biopsy specimen sampling at 2 cm above the Z-line) and 24-h impedance pH monitoring, together with a 2-week experimental treatment with esomeprazole. Results A total of 636 patients were included for the final analysis, including 352 with GERD. The sensitivity and specificity of GerdQ and 24-h impedance monitoring for diagnosing GERD were 57.7% and 48.9%, and 66.4% and 43.3%, respectively. The sensitivity of 24-h impedance pH monitoring increased to 93.7%. The sensitivity and specificity of dilated intercellular spaces (DIS) (≥0.9 μm) for diagnosing GERD were 61.2% and 56.1%, respectively, whereas those for PPI test were 70.5% and 44.4%. Conclusions GerdQ score or PPI test alone cannot accurately diagnose GERD in a Chinese population suspected of GERD. A definitive diagnosis of GERD still depends on endoscopy or 24-h pH monitoring. 24-h impedance pH monitoring may increase the sensitivity for diagnosing GERD by 20%; however, when used alone, it results in poor specificity in patients without acid suppressive therapy. [ABSTRACT FROM AUTHOR]

Apples are appreciated for their texture with firmness acting as an indicator of quality. During prolonged storage, apples can soften and their texture can become undesirably mealy. Using an X-ray microcomputer tomography (μ-CT) scanner, the porosity (ratio of intercellular space [IS] to total volume) and the structural arrangement of the parenchyma tissue of 4 apple cultivars (Braeburn, Fuji, Golden Delicious, Jazz) stored under similar conditions for 100 d were visualized via the development of 2D and 3D images. The texture of the apples was also measured using a puncture test. The morphometric and textural measurements revealed that firm Jazz apples (flesh firmness: 29.84N) had a lower porosity (17%) compared to soft Golden Delicious apples (flesh firmness: 14.16N; porosity: 29.8%). In general, firm apples had a higher dry matter (%) and a lower porosity (%), while the reverse was true for softer apples. However, this was not an absolute trend as cultivar specific differences in the microstructural organization and consequent mechanical strength of the parenchyma tissue also influenced firmness. For example, although Fuji apples were firm (28.42N), they had a high porosity (29.3%) due to the presence of numerous small and compact IS. In comparison, soft Golden Delicious apples had a high porosity (29.8%) due to the presence of large, interconnected IS. Imaging technologies have the potential to provide a pictorial or graphical database showing the size range distribution of IS corresponding to different parenchyma tissue types and how they relate to apple texture and eating quality. [ABSTRACT FROM AUTHOR]

Background: Basement membrane heparan sulfate proteoglycan (perlecan) has been demonstrated in precancer lesions and carcinomas of oral cavity. It helps in malignant transformation of epithelial cells. The aim of our study was to understand the immuno-localization of perlecan in oral dysplastic epithelium and oral carcinomas. Materials and Methods: A total of 50 cases comprising 10 normal mucosa, 20 dysplastic mucosa, and 20 oral squamous cell carcinomas (OSCC) were included in the retrospective study. They were examined for the presence of perlecan protein core by immunohistochemistry using monoclonal antibody. Interpretation of the pattern of staining was done, and majority of the observations were taken for statistical analysis. Results: In normal epithelium, perlecan was found to be present in basal layer at the cell border. In dysplastic epithelium, it was present in suprabasal layers also. With the increase in severity of dysplasia, its expression was more in suprabasal layers, and the immuno-localization was found to be at cell border and cytoplasm. In OSCC cases, perlecan was present in stroma and tumor islands. Conclusion: It was deduced from the above results that perlecan helps potentially in dysplastic changes of epithelial cells. It gets accumulated within the cell and intercellular spaces and serves as a reservoir for various growth factors. In OSCC, it breaks down and releases growth factors, which help in tumor progression, angiogenesis, and metastasis of the carcinoma. [ABSTRACT FROM AUTHOR]

Background and Aims Foliar variegation is recognized as arising from two major mechanisms: leaf structure and pigment-related variegation. Begonia has species with a variety of natural foliar variegation patterns, providing diverse examples of this phenomenon. The aims of this work are to elucidate the mechanisms underlying different foliar variegation patterns in Begonia and to determine their physiological consequences. Methods Six species and one cultivar of Begonia were investigated. Light and electron microscopy revealed the leaf structure and ultrastructure of chloroplasts in green and light areas of variegated leaves. Maximum quantum yields of photosystem II were measured by chlorophyll fluorescence. Comparison with a cultivar of Ficus revealed key features distinguishing variegation mechanisms. Key Results Intercellular space above the chlorenchyma is the mechanism of variegation in these Begonia. This intercellular space can be located (a) below the adaxial epidermis or (b) below the adaxial water storage tissue (the first report for any taxa), creating light areas on a leaf. In addition, chlorenchyma cell shape and chloroplast distribution within chlorenchyma cells differ between light and green areas. Chloroplasts from both areas showed dense stacking of grana and stroma thylakoid membranes. The maximum quantum yield did not differ significantly between these areas, suggesting minimal loss of function with variegation. However, the absence of chloroplasts in light areas of leaves in the Ficus cultivar led to an extremely low quantum yield. Conclusions Variegation in these Begonia is structural, where light areas are created by internal reflection between air spaces and cells in a leaf. Two forms of air space structural variegation occur, distinguished by the location of the air spaces. Both forms may have a common origin in development where dermal tissue becomes loosely connected to mesophyll. Photosynthetic functioning is retained in light areas, and these areas do not include primary veins, potentially limiting the costs of variegation. [ABSTRACT FROM PUBLISHER]

Background/introduction: Dilatation of intercellular space (IS) of esophageal epithelial cells is described as a sensitive early marker for epithelial damage by refluxate. Esophageal epithelia are morphologically subdivided into three layers according to the shape of the cells and nuclei. Meanwhile, ten transmission electron microscopy (TEM) photographs and ten randomly selected measurements per photo from gastroesophageal reflux disease (GERD) patients have been widely accepted without any theoretical criticism. We assumed that the IS differs among each layer and thus studied IS according to subdivided layers of normal esophageal epithelium. We also evaluated an optimal number of IS measurements per photograph.Materials and Methods: Esophagogastroduodenoscopy was performed in 15 healthy adults without any symptom of GERD, taking biopsies from mucosa above 5 cm from the squamo-columnar junction. Tissues were handled and prepared for TEM, verifying three layers of esophageal mucosa, i.e., squamous cell layer, prickle cell layer, and basal layer. Ten digital photomicrographs were taken from each three layers by TEM, and ISs were measured with a computerized image analysis program. For the method of measuring IS, 5, 10, 20, 30, and 40 measurements per photomicrograph were respectively performed by four different examiners. Mean value and intraclass correlation coefficient (ICC) was also yielded.Results: Mean IS of lower esophagus irrelevant to three epithelial layers were 0.39 ± 0.30 μm. When subdivided into three layers, however, mean IS of squamous cell layer was 0.62 ± 0.23 μm, prickle cell layer 0.23 ± 0.19 μm, and basal layer 0.55 ± 0.36 μm, with their difference statistically significant (p < 0.05). On the other hand, ICC of 5, 10, 20, 30, and 40 measurements were 0.688, 0.917, 0.837, 0.790, and 0.765, respectively.Conclusions: Mean IS values of each three layers of esophageal epithelium in normal subjects were significantly different, and reconsideration of the standard measurement method is needed. Ten measurements per photo had an adequate inter-observer agreement. [ABSTRACT FROM AUTHOR]

Aluminium (Al) toxicity and drought are the two major abiotic stress factors limiting common bean production in the tropics. Using hydroponics, the short-term effects of combined Al toxicity and drought stress on root growth and Al uptake into the root apex were investigated. In the presence of Al stress, PEG 6000 (polyethylene glycol)-induced osmotic (drought) stress led to the amelioration of Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1. PEG 6000 (>> PEG 1000) treatment greatly decreased Al accumulation in the 1 cm root apices even when the roots were physically separated from the PEG solution using dialysis membrane tubes. Upon removal of PEG from the treatment solution, the root tips recovered from osmotic stress and the Al accumulation capacity was quickly restored. The PEG-induced reduction of Al accumulation was not due to a lower phytotoxic Al concentration in the treatment solution, reduced negativity of the root apoplast, or to enhanced citrate exudation. Also cell-wall (CW) material isolated from PEG-treated roots showed a low Al-binding capacity which, however, was restored after destroying the physical structure of the CW. The comparison of the Al3+, La3+, Sr2+, and Rb+ binding capacity of the intact root tips and the isolated CW revealed the specificity of the PEG 6000 effect for Al. This could be due to the higher hydrated ionic radius of Al3+ compared with other cations (Al3+ >> La3+ > Sr2+ > Rb+). In conclusion, the results provide circumstantial evidence that the osmotic stress-inhibited Al accumulation in root apices and thus reduced Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1 is related to the alteration of CW porosity resulting from PEG 6000-induced dehydration of the root apoplast. [ABSTRACT FROM PUBLISHER]

The article examines the methods being used or developed in the identification of extracellular and intercellular characteristics of cultured cells and tissues. The physical and chemical features involved in the dynamics of chemical movement within the cell boundary layers are described. Although biological membrane properties are considered difficult to measure directly, it is clear that cell activity produces distinct chemical signatures.

Abstract: In this work the gas diffusion of ‘Golden’ papaya fruit (Carica papaya L.) was evaluated as a function of different maturity stages, by using a photoacoustic spectrometer. The maturity stages were characterized by the anatomical changes, membrane integrity, pulp firmness, and skin color. Microstructural analysis was performed by means of light and scanning electron microscopy. A significant decrease in the diffusion rate with ripening was observed. Under the experimental conditions it was found that fruit in maturity stage 0 (less mature) had turgid, regular shape parenchyma cells, and relatively little intercellular spaces. However, fruit in maturation stage 5 (more mature) showed separation of cell walls and pectic substance accumulation into the intercellular spaces. The skin color showed a reduction in hue angle values and an increase in chromaticity parameters a* and b*, characterizing the loss of green color during ripening. A loss of firmness of the pulp was also observed during fruit ripening. [Copyright &y& Elsevier]

Gastroesophageal reflux disease (GERD) can be associated with ear, nose, and throat signs and symptoms, a condition often referred to as laryngopharyngeal reflux (LPR). However, the morphologic alterations of laryngeal mucosa associated with LPR are currently poorly understood. Since the dilation of intercellular spaces (DIS) between squamous epithelial cells is considered a morphologic marker of acid damage to esophageal mucosa in GERD, we evaluated whether similar changes can be detected in the laryngeal epithelium of patients affected by LPR. The study group included 15 patients affected by LPR and 7 normal controls, who underwent laryngeal biopsies at the interarytenoid area. Specimens were routinely processed for light microscopic and ultrastructural examination. The intercellular spaces were measured in electron microscopy images using a computer assisted morphometric system. Ultrastructural analysis demonstrated an irregular intercellular space dilation in specimens from the group of patients with LPR. Another ultrastructural abnormality observed in a minority of patients was the presence of numerous cytoplasmic vacuoles. Computer assisted morphometric analysis demonstrated that the intercellular space between squamous cells was significantly wider in patients with LPR than in control subjects (411.7 nm ± 188.6 SD vs. 155.8 nm ± 56.4 SD, P = 0.003). These data indicate that ultrastructural evidence of DIS of epithelial cells may be a morphologic marker of acid reflux, as already described in esophageal mucosa. If this result will be confirmed in larger series it may provide a useful diagnostic tool for the identification of LPR. [ABSTRACT FROM AUTHOR]

In order to understand the characteristics of burnt meat in cultured yellowtail Seriola quinqueradiata, fish were kept at two different temperatures (13 and 30°C) and slaughtered by either spinal cord destruction (SCD) or suffocation in air (SA). Early postmortem changes during storage at 32°C were analyzed by rheological, biochemical, and histological methods. The burnt meat (with lightness parameter, L* ≥ 55) was observed at 1-h storage in the SA 30°C group, at 2 h in SCD 30°C, and at 4 h in SA 13°C; meat was normal for the SCD 13°C group until 6 h of storage. Breaking strength scores were higher for the normal meat (200 g/cm2) than burnt meat (70 g/cm2) at 4 h of storage. Expressible water content was higher for the burnt meat than for the normal meat. Adenosine triphosphate concentrations for the SCD groups were higher than for the SA counterparts. Moreover, pH decrease was much faster in the 30°C groups, showing pH 5.6 at 2 h of storage. A negative correlation between the pH and lactic acid contents in muscle ( P < 0.001) was found. Histological analysis evidenced a larger pericellular area (40%) in the burnt samples than in the normal samples (16%). It was confirmed that a higher fish-keeping water temperature and a stressful slaughter method (faster glycolytic process) were determinative factors that influence the occurrence of burnt muscle in yellowtail, and that the effect of the former is larger than the latter. [ABSTRACT FROM AUTHOR]

A detailed quantitative analysis of the three-dimensional organization of the mesophyll was performed, and mesophyll diffusion resistance to CO2 in the leaves of Chamaerion angustifolium formed under different irradiance was calculated using an original method of stereometric cellular packing. For each type of leaves (sun and shade), we determined structural components of gas exchange: the volume of mesophyll per unit leaf area ( V mes), the volume of the intercellular space in the mesophyll ( V is), the area of the total mesophyll surface ( S), the area of the free mesophyll surface facing the intercellular spaces ( S mes), and the ratios of the total and the free mesophyll surfaces to its volume ( S/V and S mes/ V). As compared with sun leaves, in the shade leaves of Ch. angustifolium, S and V mes decreased twofold, tissue density was reduced twofold, and the share of the intercellular space in the mesophyll rose from 49 to 72%. In shade, the diffusion resistance of the mesophyll increased by 1.8 times because of changes in the leaf structure. At the same time, the ratio S mes/ V was found to increase by 1.4 times, which facilitated the diffusion of CO2. In the shade leaves of Ch. angustifolium, the diffusion resistance of the intercellular air spaces was reduced twofold as a result of an increase in their share in the leaf mesophyll and simplification of their geometry. Thus, the method of three-dimensional reconstruction of sun and shade leaves of Ch. angustifolium showed a comprehensive rearrangement of the mesophyll spatial organization in shade and revealed the structural mechanisms of changes in the resistance to CO2 diffusion within the leaf. [ABSTRACT FROM AUTHOR]

The radial disposition of air in the flesh of fruit of Malus domestica Borkh., cv ‘Braeburn’ was investigated using a gravimetric technique based on Archimedes’ principle. Intercellular air volume was measured by weighing a small tissue sample under water before and after vacuum infiltration to remove the air. In a separate procedure, the volume of the same sample was measured by recording the buoyant upthrust experienced by it when fully immersed in water. The method underestimates tissue air volume due to a slight invasion of the intercellular air spaces around the edges of the sample when it is immersed in water. To correct for this error, an adjustment factor was made based upon an analysis of a series of measurements of air volume in samples of different dimensions. In ‘Braeburn’ there is a gradient of declining air content from just beneath the skin to the centre of the fruit with a sharp discontinuity at the core line. Cell shape and cell packing were observed in the surface layers of freshly excised and stained flesh samples using a dissecting microscope coupled to a video camera and a PC running proprietary software. Tissue organization changed with distance below the skin. It is speculated that reduced internal gas movement, due to the tightly packed tissue of ‘Braeburn’ and to the potential diffusion barrier at the core line between the cortex and the pith, may increase susceptibility of the flesh to disorders associated with tissue browning and breakdown. [ABSTRACT FROM PUBLISHER]

Blood-tissue barriers preventing an uncontrolled exchange of larger molecules between adjacent but metabolically separate compartments have been demonstrated in various organs. One prominent example is the blood-testis barrier which has been investigated in a number of species. A key function of this barrier is to shield developing germ cells from the immune system in order to avoid autoimmune reactions. This requirement also applies to the male excurrent duct system. Yet, very few investigations have addressed the morphology of the blood-epididymal barrier. The goal of the present study, therefore, was to revisit the blood-testis barrier in the dog and to identify the structures constituting the blood-epididymal barrier in this species. Lanthanum nitrate was used as a tracer for electron microscopy. In the testis, lanthanum had free access to the intercellular space of the seminiferous epithelium up to the Sertoli cell junctions. Similarly, epithelial tight junctions were found to represent the permeability barrier in the epididymis. The present study highlights species differences with respect to the blood-testis barrier and extends the knowledge of the blood-epididymal barrier by providing morphofunctional data in this domestic species. Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Mass transfer characteristics are closely related to the cell structures. When cellular material comes in contact with a solution of high concentration, changes in physical properties of cellular material occurred throughout the process at a different degree depending on the process conditions and material matrix characteristics. Six possible situations, Cases I–VI, of changes in cell structure immersed in solution of high concentration are proposed. In this study, the specific influence of red beet tissue shrinkage on mass transfer in 600 g/kg sucrose solution at 25°C is discussed. The changes of cell unit and an analogical cellular structure are discussed. In the solid–liquid contacting period, the situation of volume changes of cell unit of red beet material remained in the no cell volume change (Cases I and II) condition. In most cases, the volume of extracellular space of cellular material decreased with water transfer out of tissue, then material matrix began to collapse, resulting in the changes in porosity. The porosity changes in the no cell volume change cases (Cases I and II) were considered as special conditions without the consideration of cellular material tissue shrinkage. The tissue structure shrinkage cases (Cases III–VI) were considered to occur more often when a fresh, soft cellular material tissue such as fruits and vegetables was contacted with osmotic solution of high concentration. [Copyright &y& Elsevier]

• Mie's theory allows modeling of light scattering based on the apple microstructure. • Intercellular space and starch granules dominate light scattering in cortex tissue. • Microstructural changes during maturation predict a decrease in scattering by 30 %. • From apple core to skin, the model results in an increase in scattering by 35 %. • Dissolution of the middle lamella can explain increasing scattering during storage. Mie's theory was used to develop a theoretical model to describe light propagation in apple tissue based on its microstructural properties. Taking into account the size distributions and volume fractions of intercellular space and starch granules, which are known in detail from previous studies, the model predicted a decrease in the effective scattering coefficient μ ′ s of about 30 % during maturation. For the lateral change of μ ′ s within a ripe apple, the model predicted an increase up to 35 % from core to skin. In both cases, the relative changes agree well with the experimental results obtained with spatial frequency domain imaging (SFDI) and an integrating sphere setup. Based on the model, at least 70 % of total μ ′ s is attributable to intercellular space, which accordingly plays a dominant role in the temporal and lateral change of scattering. Using an extended Mie model for layered particles assuming a dense cell structure, a negligible effect on μ ′ s was observed for the cell wall. However, for cells separated from the surrounding tissue by a narrow air gap (e.g. dissolution of the middle lamella), μ ′ s was 20 % higher than for cells theoretically isolated in air. Lastly, it was shown that an increase in soluble solids content (SSC) during maturation by up to 15 % and the associated higher refractive index in the cells led to an increase in μ ′ s by about 3–5 % compared to the case without considering SSC. Overall, the application of Mie's theory proved suitable to investigate the influence of different morphological structures on light scattering in apple tissue. [ABSTRACT FROM AUTHOR]