Intercellular Material Research Articles

Imaging of Single Cell by Laser Speckle Microscopy

Laser speckle microscopy was developed to observe a single living cell without any troublesome labeling preparation. The system consists of an optical microscope, a laser source, and a video camera. The technique has an advantage that ellular conditions can be instantaneously determined by observing speckle fluctuations. In the experiments, living and fixed HeLa cells were compared on the basis of speckle fluctuation and frequency spectra. By applying this technique to cell observations, it is expected to estimate not only cellular activity but also real-time movements of intercellular materials including the cytoplasm without fluorescence observation.

Integral Lipid in Human Hair Follicle

On the hair surface, cells are covered with a thin lipid layer (LL) covalently bonded to hair proteins. This integral hair lipid is different from sebaceus lipid. We conducted this study to examine the lipid distribution in human hair follicle. Transmission electron microscopy was performed to observe the ultrastructure of the LL. Hair follicles were cut and observed longitudinally along the hair axis. For transmission electron microscopy, new fixative (Lee's fixative: composed of OsO4 and RuO4) was designed as the conventional fixatives such as OsO4 or RuO4 alone were not appropriate for staining for hair follicle lipid. In addition, we measured the chemical composition of integral hair lipid by high-performance thin-layer chromatography. From the above experimental procedure, it was discovered that the lipid in the hair follicle was mainly distributed in hair cuticle and keratinized inner root sheath. A multitude of lamellar granule is observed in the vicinity of the above LL. The chemical composition of integral hair lipid was different from those of epidermal or sebaceous lipids. It is assumed that the LL in the hair follicle is similar to the epidermal LL playing an important role as a skin barrier in the stratum corneum. We proposed here the new terminology "hair barrier" from this point of view.

Hyper-adhesion in desmosomes: its regulation in wound healing and possible relationship to cadherin crystal structure

The resistance of tissues to physical stress is dependent upon strong cell-cell adhesion in which desmosomes play a crucial role. We propose that desmosomes fulfil this function by adopting a more strongly adhesive state, hyper-adhesion, than other junctions. We show that the hyper-adhesive desmosomes in epidermis resist disruption by ethylene glycol bis(2-aminoethyl ether)-N,N,N'N'-tetraacetic acid (EGTA) and are thus independent of Ca2+. We propose that Ca2+ independence is the normal condition for tissue desmosomes. Ca2+ independence is associated with an organised arrangement of the intercellular adhesive material exemplified by a dense midline. When epidermis is wounded, desmosomes in the wound-edge epithelium lose hyper-adhesiveness and become Ca2+ dependent, i.e. readily dissociated by EGTA. Ca2+-dependent desmosomes lack a midline and show narrowing of the intercellular space. We suggest that this indicates a less-organised, weakly adhesive arrangement of the desmosomal cadherins, resembling classical cadherins in adherens junctions. Transition to Ca2+ dependence on wounding is accompanied by relocalisation of protein kinase C alpha to desmosomal plaques suggesting that an 'inside-out' transmembrane signal is responsible for changing desmosomal adhesiveness. We model hyper-adhesive desmosomes using the crystal packing observed for the ectodomain of C-cadherin and show how the regularity of this 3D array provides a possible explanation for Ca2+ independence.

Immunocytochemical localization of the pathogenesis-related PR-1 protein in barley leaves after infection by Bipolaris sorokiniana

A pathogenesis-related PR-1 protein accumulates in barley ( Hordeum vulgare L.) leaves upon pathogen attack. The hyphae of Bipolaris sorokiniana invades primarily the intercellular space of mesophyll tissue. Light microscopy revealed that infected leaves show PR-1 labeling on mesophyll cell walls and both infected and non-infected leaves show labeling in chloroplasts. Subcellularly, PR-1 was detected on the outer cell wall layer and cytoplasm of primary hyphae, on intercellular electron dense material in junctions between host cells and in host cell wall appositions. The role of PR-1, as a defense and/or senescence related protein, in relation to its subcellular localizations is discussed.

Influence of grain direction in vibrational wood welding

Abstract Wood grain orientation differences in the two surfaces to be bonded yield bondlines of different strength in no-adhesives wood welding. Longitudinal wood grain bonding of tangential and radial wood sections yields an approximately 10% difference in strength results of the joint. Cross-grain (±90°) bonding yields instead a much lower strength result, roughly half that observed for pieces bonded with the grain parallel to each other. These differences can be explained by the very marked effect that homogeneity of fibre orientation is known to have on fibre–matrix composites. Oak yields lower results than beech and maple and is more sensitive to welding conditions. Differences in both anatomical and wood constituent composition can account for this difference in performance. Contrary to the other wood species, oak always presents joint bondlines where little or no increase in density at the interface is noticed. This explains its somewhat lower strength results. This is based on the different mode of bonding predominant in this species, while the other species present two different modes of bonding. Thus, two types of bondlines are observed by scanning electron microscopy (SEM): (i) bondlines where entangled fibre–matrix composites are formed at the interface and (ii) bondlines in which direct welding of the cell walls occurs, just by fused intercellular material or cell surface material. In this latter case the cells remain flat, without an entangled fibre–matrix composite being formed. This is the almost exclusively predominant case for oak. Both cases and even hybrid cases between the two have also been observed in beech.

Interaction between matrix metalloproteinase 3 and the ε4 allele of apolipoprotein E increases the risk of Alzheimer’s disease in Finns

Polymorphisms affecting the expression of matrix metalloproteinases (MMPs), i.e. proteolytic enzymes that degrade intercellular material, have been found at position −1607 (1G/2G) in MMP1 and at −1171 (5A/6A) in MMP3. Interestingly, elevated levels of MMP1 and MMP3 have been observed in the brains of Alzheimer’s disease (AD) patients and those of tissue inhibitors of MMPs in the cerebrospinal fluid of AD and Parkinson’s disease (PD) patients, suggesting a role for MMPs in these disorders. The aim was to investigate a possible association between the afore-mentioned MMP1 and MMP3 polymorphisms and the risk of developing AD or PD. The polymorphisms were genotyped in 97 AD, 52 PD and 101 control patients. We found an interaction between MMP3*5A and APOE ε4 alleles ( P < 0.0001) which increases the risk of AD (OR: 23.7, 95% CI: 5.8–144.9, P < 0.0001) compared to those who possess neither MMP3*5A nor APOE ε4. In conclusion, our finding suggests that the MMP3 gene, especially together with APOE ε4, may contribute to the development of AD.

Behaviors of intercellular materials and nutrients in biological nutrient removal process supplied with domestic wastewater and food waste.

A four-stage biological nutrient removal (BNR) process was operated to investigate the effect of anaerobically fermented leachate of food waste (AFLFW) as an external carbon source on nutrient removal from domestic wastewater having a low carbon-to-nitrogen ratio. The BNR system that was supplemented with AFLFW showed a good performance at a sludge retention time (SRT) of 30 days, despite low temperature. With this wastewater, average removal efficiencies of soluble chemical oxygen demand (COD), total nitrogen (T-N), and total phosphorus (T-P) were 88 to 93%, 70 to 74%, and 63 to 68%, respectively. In this study, several kinds of poly-hydroxyalkanoates (PHAs) were observed in cells. These included 24% poly-3-hydroxybutyrate (PHB), 41% poly-3-hydroxyvalerate (PHV), 18% poly-3-hydroxyhexanoate (PHH), 10% poly-3-hydroxyoctanoate (PHO), 5% poly-3-hydroxydecanoate (PHD). and 2% poly-3-hydroxydodecanoate (PHDD), indicating that microorganisms could store various PHAs through the different metabolic pathways. However, breakdown of the enhanced biological phosphorus removal (EBPR) mechanism was observed when SRT increased from 30 to 50 days for the enhancement of nitrification. To study the effect of SRT on EBPR, a sequencing batch reactor (SBR) system that was supplied with glucose was operated at various SRTs of 5, 10, and 15 days. Nitrification and denitrification efficiencies increased as SRT increased. However, the content of intracellular materials such as PHAs, glycogen. and poly-P in cells decreased. From these results, it was concluded that SRT should be carefully controlled to increase nitrification activity and to maintain biological phosphorus removal activity in the BNR process.

Bacterioclastic Action of a Bis-Quaternary Ammonium Compound against Escherichia coli

It has been reported that the bactericidal action of bis-quaternary ammonium compounds (bis-QACs) is little influenced by the molecular hydrophobicity. of the drug or environmental conditions such as temperature or pH. In order to clarify the mode of bactericidal action of bis-QACs against Escherichia coli, the bacterioclastic action of 4, 4'-(1, 6-hexamethylenedithio) bis (1-octylpyridinium bromide) (4DTBP-6, 8) was investigated. It was suggested that 4DTBP-6, 8, which invaded the bacterial cell, induced the leakage of ATP and the inhibition of the respiratory enzymes, and resulted in cell death. Subsequently, over 2μg/ml of4DTBP-6, 8 caused an increase in the turbidity of the cell suspension, and the bactericidal activity of 4DTBP-6, 8 was extremely increased with the increase of its concentration (over 2μg/ml). It indicated that 4DTBP-6, 8 has an ability to induce a rapid and abundant secretion of the turbid materials from the cells and that such bacterioclastic ability is connected to its potent bactericidal activity. In addition, it was suggested that the first stage of bacterioclastic action of 4DTBP-6, 8 was the leakage of magnesium ion (Mg2+), and the leakage of the outer membrane pore protein E and lipopolysaccharides followed it. The formation of blebs and holes on the bacterial cell surface was revealed by scanning electron microscopic investigation. Transmission electron micrographs of the cells treated with 4DTBP-6, 8 showed the destruction of peptidoglycan and large missing portions of intercellular materials. Judging from these results, as the mechanism of the bacterioclastic action of bis-QACs, it is suggested that the cationic parts of bis-QACs electrically interact with the cationic parts of Mg2+ on the bacterial surface, then bis-QACs invade the cell membrane by displacement reaction with Mg2+, and rapidly destroy the bacterial cell surface structure.

Dermatofibroma: Upregulation of Syndecan-1 Expression in Mesenchymal Tissue

Cell surface proteoglycans play a prominent role in tissue remodeling and homeostasis. Syndecans, their most prominent members, act by binding to growth factors and interstitial matrix molecules. They, thereby, modulate the effect of the primary ligand-receptor interaction at the cell membrane by increasing the affinity of cell-ligand interactions. Additionally, they influence the strength of cell-cell and cell-matrix interactions. Syndecan-1 is the prototypical member of this family of proteins. Under physiological conditions, its expression is restricted to the epidermis, the outer root sheath of the anagen hair follicle, and the sweat gland epithelium. The dermal compartment-with the exception of the follicular papilla of the anagen hair follicle-physiologically does not express syndecan-1. Dermatofibromas are mesenchymal lesions, which often exhibit hyperplastic changes in the overlying epidermis. In analogy to the hair follicle, they, thereby, can be used as a model for studying epithelial-mesenchymal interactions. In the current study, we examined dermatofibromas immunohistochemically for syndecan-1 expression. We report immunoreactivity for syndecan-1 in dermatofibromas, which correlates mainly with the deposition of intercellular matrix material. Syndecan-1 is also noted in the stroma surrounding areas of basaloid hyperplasia overlying dermatofibromas and may be important in the pathogenesis of this inductive phenomenon. In analogy to the follicular papilla of the anagen hair follicle, the staining pattern for syndecan-1 in dermatofibromas indicates that this cell surface protein is produced by stromal cells and most likely serves an essential function in the growth of these common mesenchymal cutaneous lesions.

Intercellular organelle traffic through cytoplasmic bridges in early spermatids of the rat: mechanisms of haploid gene product sharing.

Stable cytoplasmic bridges (or ring canals) connecting the clone of spermatids are assumed to facilitate the sharing of haploid gene products and synchronous development of the cells. We have visualized these cytoplasmic bridges under phase-contrast optics and recorded the sharing of cytoplasmic material between the spermatids by a digital time-lapse imaging system ex vivo. A multitude of small (ca. 0.5 microm) granules were seen to move continuously over the bridges, but only 28% of those entering the bridge were actually transported into other cell. The average speed of the granules decreased significantly during the passage. Immunocytochemistry revealed that some of the shared granules contained haploid cell-specific gene product TRA54. We also demonstrate the novel function for the Golgi complex in acrosome system formation by showing that TRA54 is processed in Golgi complex and is transported into acrosome system of neighboring spermatid. In addition, we propose an intercellular transport function for the male germ cell-specific organelle chromatoid body. This mRNA containing organelle, ca. 1.8 microm in diameter, was demonstrated to go over the cytoplasmic bridge from one spermatid to another. Microtubule inhibitors prevented all organelle movements through the bridges and caused a disintegration of the chromatoid body. This is the first direct demonstration of an organelle traffic through cytoplasmic bridges in mammalian spermatogenesis. Golgi-derived haploid gene products are shared between spermatids, and an active involvement of the chromatoid body in intercellular material transport between round spermatids is proposed.

Surface Properties of the Skin of the Pilot Whale Globicephala melas

On the skin surface of delphinids small biofoulers are challenged to high shear water flow and liquid-vapor interfaces of air-bubbles during jumping. This state of self-cleaning is supported by the even, nano-rough gel-coated epidermal surface of the skin. The present study focussed on the intercellular evolution of gel formation and the chemical composition of the gel smoothing the skin surface of the pilot whale, Globicephala melas , using X-ray photoelectron spectroscopy (XPS) in combination with cryo-scanning electron microscopy (CSM), and transmission electron microscopy (TEM). In the superficial layer of the epidermis, the stratum corneum, intercellular material was shown by electron optical methods to assemble from smaller into larger covalently cross-linked aggregates during the transit of the corneocytes towards the skin surface. XPS measurements showed that the surface of the skin and the intercellular gel included approximately the same amounts of polar groups (especially, free amines and amides) and non-polar groups, corresponding to the presence of lipid droplets dispersed within the jelly material. It was concluded from the results that the gel-coat of the skin surface is a chemically heterogeneous skin product. The advantages of chemically heterogeneous patches contributing to the ablation of traces of the biofouling process are discussed.

Dewatering of activated sludge by Fenton's reagent

The specific resistance, moisture and element analysis were used to evaluate the increase in filtration and dewatering efficiency when applying the Fenton system, Fe 2+/H 2O 2 and Fe 3+/H 2O 2, to treat excess sludge. Addition of Fe 2+, Fe 3+ and H 2O 2 were also selected as treatment processes for comparison. The excess sludge used in this study was obtained from the wastewater treatment plant of An-Ping Industrial Park in Tainan, Taiwan. Results show that ferrous and ferric ions can catalyze hydrogen peroxide to promote the filterability of sludge. Four ratios of Fe 2+/H 2O 2 were used to investigate the effect of Fe 2+ concentration on the reduction of specific resistance. When 6000 mg/l of Fe 2+ and 3000 mg/l of H 2O 2 were added into the sludge, the specific resistance of the treated sludge had only 10% of that of the original sludge. Ferric ions also have high catalyzing ability similar to ferrous ions. However, Fenton's reagent, Fe 2+/H 2O 2, has a higher dewatering efficiency than other processes. The moisture of the cake sludge generated by treatment with Fenton's reagent was 75.2%, and those conditioned by other processes were approximately 85%. The mechanism by which Fenton's reagent increased the sludge dewaterability could be the destruction of cells leading to the release of the intercellular material.

Hypersensitive cell death and post-haustorial defence responses arrest the orange rust (Hemileia vastatrix) growth in resistant coffee leaves

The growth of a coffee orange rust fungus (Hemileia vastatrix Berk and Br.) isolate (race II) and the sequence of responses it induced in leaves of resistant Coffea arabica L. and C. congensis Froehner as well as on a susceptible C. arabica were investigated cytologically and biochemically. The percentages of germinated urediospores and of appressoria formed over stomata as well as the fungal growth inside leaf tissues were similar in resistant and susceptible leaves until the 3rd day after the inoculation. In the susceptible leaves, at the majority of the infection sites (70%) the fungus pursued its growth without apparent inhibition while in the resistant leaves the fungus ceased its growth with higher frequency (34% in C. arabica and 54% in C. congensis) after the formation of at least one haustorium. The first signs of incompatibility, detected 2 days after the inoculation, were cytologically expressed by hypersensitive host cell death (HR), host cell wall autofluorescence and haustoria encasement with callose and β-1,4-glucans. Biochemically, two peaks of phenylalanine ammonia-lyase (PAL) activity were detected by 2 and 5 days after the inoculation. The 1st peak coincided with the early accumulation of phenolic compounds and with the beginning of cell death. The 2nd peak could be related to later accumulation of phenols and the lignification of the host cell walls. About 5–7 days after the inoculation, ultrastructural observations revealed the accumulation of a material partially crystallized in the intercellular spaces around the senescent hyphae, next to dead host cells and in close association with the middle lamella that initially labelled for pectins. It also contained polysaccharides and phenolic-like compounds. Cellulose, hemicellulose, extensins, hydroxyproline-rich glycoproteins and proteins were not detected. The hypertrophy of the host cells in the infection area were also observed around 12 days after the inoculation corresponding macroscopically to the reaction flt.In susceptible plants, cell death was also observed 3 days after the inoculation but only in a reduced percentage of infection sites in which the fungus aborted at an early stage. A late haustorium encasement and stimulation of PAL activity were also observed but these delayed host responses did not prevent fungal growth and sporulation.The intercellular material, only observed in the resistant plants, is here reported for the first time and although its role is unknown it might be the result of plant cell death.

Immunochemical detection of a fluorophore derived from the lipid peroxidation product 4-hydroxy-2-nonenal and lysine.

Aging and the progression of certain degenerative diseases are accompanied by increases in intra- and intercellular fluorescent material, termed lipofuscin and ceroid, respectively (for review, see refs. ,. These pigments are observed within granules composed, in part, of damaged protein and lipid. Modification of various biomolecules by aldehyde products of lipid peroxidation is believed to contribute to lipofuscin and ceroid formation. However direct evidence demonstrating the occurrence of lipid peroxidation product-derived fluorophores on protein components of lipofuscin or ceroid has yet to be obtained (for review, see refs. ,). We have recently identified a fluorescent product formed in the reaction of Nα-acetyllsyine (NAL) and 4-hydroxy-2-nonenal (HNE) (), a major product of lipid peroxidation and the most reactive of these compounds under physiological conditions (). This fluorescent compound, characterized as a2-hydroxy-3-imino-1,2-dihydropyrrol derivative (3, R1 = R2 = NAL), appears to form upon oxidative cyclization of the nonfluorescent 2:1 lysine-HNE Michael adduct-Schiff base cross-link (Scheme 1). Polyclonal antibody (PAb) to the NAL-HNE fluorophore was raised in rabbit and found to be highly specific to the chromophore structure of the compound (). This antibody has been used to demonstrate the formation of the lysineHNE derivative of this fluorophore upon exposure of protein to HNE in vitro.

Immunohistochemical detection of amelogenin and cytokeratin 19 in epithelial odontogenic tumors

Epithelial odontogenic tumors exhibit considerable histological variation and are classified into several benign and malignant entities. Expression of amelogenin and cytokeratin 19 (CK19), that are potentially useful polypeptides for identification of odontogenic epithelial components, was evaluated in various types of epithelial odontogenic tumors. Specimens of 33 ameloblastomas, three calcifying epithelial odontogenic tumors (CEOTs), two clear cell odontogenic tumors (CCOTs) and five malignant ameloblastomas were examined by immunohistochemistry using anti-amelogenin and anti-CK19 antibodies. Immunohistochemical reactivity for amelogenin was detected in many peripheral columnar or cuboidal cells and some central polyhedral cells in ameloblastomas, and histological variants showed various degrees of amelogenin expression. Expression of CK19 was diffusely present in neoplastic cells in ameloblastomas, and decreased expression was found in keratinizing cells of acanthomatous variants and some neoplastic cells of desmoplastic variants. In CEOTs, immunohistochemical reactivity for amelogenin was detected in neoplastic cells and intercellular amyloid-like materials, whereas CK19 was expressed in neoplastic cells. CCOTs showed positive reactivity for amelogenin and CK19 in neoplastic cells. Malignant ameloblastomas exhibited various degrees of amelogenin expression with constant CK19 expression in neoplastic cells. Diverse types of epithelial odontogenic tumors express amelogenin and CK19, suggesting that these tumors have ameloblastic differentiation or odontogenic epithelial properties.

Role of alginate and its O acetylation in formation of Pseudomonas aeruginosa microcolonies and biofilms.

Attenuated total reflection/Fourier transform-infrared spectrometry (ATR/FT-IR) and scanning confocal laser microscopy (SCLM) were used to study the role of alginate and alginate structure in the attachment and growth of Pseudomonas aeruginosa on surfaces. Developing biofilms of the mucoid (alginate-producing) cystic fibrosis pulmonary isolate FRD1, as well as mucoid and nonmucoid mutant strains, were monitored by ATR/FT-IR for 44 and 88 h as IR absorbance bands in the region of 2,000 to 1,000 cm(-1). All strains produced biofilms that absorbed IR radiation near 1,650 cm(-1) (amide I), 1,550 cm(-1) (amide II), 1,240 cm(-1) (P==O stretching, C---O---C stretching, and/or amide III vibrations), 1,100 to 1,000 cm(-1) (C---OH and P---O stretching) 1,450 cm(-1), and 1,400 cm(-1). The FRD1 biofilms produced spectra with an increase in relative absorbance at 1,060 cm(-1) (C---OH stretching of alginate) and 1,250 cm(-1) (C---O stretching of the O-acetyl group in alginate), as compared to biofilms of nonmucoid mutant strains. Dehydration of an 88-h FRD1 biofilm revealed other IR bands that were also found in the spectrum of purified FRD1 alginate. These results provide evidence that alginate was present within the FRD1 biofilms and at greater relative concentrations at depths exceeding 1 micrometer, the analysis range for the ATR/FT-IR technique. After 88 h, biofilms of the nonmucoid strains produced amide II absorbances that were six to eight times as intense as those of the mucoid FRD1 parent strain. However, the cell densities in biofilms were similar, suggesting that FRD1 formed biofilms with most cells at depths that exceeded the analysis range of the ATR/FT-IR technique. SCLM analysis confirmed this result, demonstrating that nonmucoid strains formed densely packed biofilms that were generally less than 6 micrometer in depth. In contrast, FRD1 produced microcolonies that were approximately 40 micrometer in depth. An algJ mutant strain that produced alginate lacking O-acetyl groups gave an amide II signal approximately fivefold weaker than that of FRD1 and produced small microcolonies. After 44 h, the algJ mutant switched to the nonmucoid phenotype and formed uniform biofilms, similar to biofilms produced by the nonmucoid strains. These results demonstrate that alginate, although not required for P. aeruginosa biofilm development, plays a role in the biofilm structure and may act as intercellular material, required for formation of thicker three-dimensional biofilms. The results also demonstrate the importance of alginate O acetylation in P. aeruginosa biofilm architecture.

Ultrastructure of ovarian follicular epithelium of the Amazonian fish Pseudotylosurus microps (Teleostei: Belonidae): morphological and histochemical characterization of the intercellular deposits.

The present paper reports the presence of great quantities of electrondense intercellular material in the follicular epithelium of P. microps. The material apparently is uptaken from circulation and enter the follicle through the intercellular spaces accumulating in the epithelial median-apical intercellular spaces and in perioocytic space. The accumulation starts in the early growth of the primary oocyte and proceed until vitellogenesis. The possible chemical nature and function of the deposits are discussed.

The molecular chaperone system and other anti-stress mechanisms in Archaea

This article presents a brief review of stressors, their cellular and intracellular targets, stress proteins, molecular chaperones, and other anti-stress mechanisms. New data are reported on cochaperones and multicellular structures in archaea. The molecular chaperoning systems of bacteria and eukaryotes have been studied for many years and are relatively well known in terms of their components and mechanisms of action, although many details remain to be elucidated and almost certainly other components will be discovered in the future. By comparison, the molecular chaperoning system of archaea is still unexplored. Since archaea have some molecular genetic and physiologic features similar to those of bacteria and some resembling those of eukaryotes, extrapolation from what is known of organisms from these two phylogenetic domains to archaeal species is unwarranted. For example, the components of the molecular chaperone machine, Hsp70(DnaK), Hsp40(DnaJ), and GrpE, in the archaeal species that have it, are closely related to bacterial counterparts, whereas the archaeal chaperonins are like the eukaryotic equivalents. Furthermore, many archaeal species lack the chaperone machine, in contrast to bacteria and eukaryotes that have it without any known exception. A search for the cochaperones trigger factor, Hop, Hip, BAG-1, and NAC in archaeal genomes demonstrated no conserved equivalents, but two families of archaeal molecules were identified that might be related to NAC and Hop, respectively. Multicellular structures with a single species such as packet and lamina are formed by Methanosarcina species, among which the best studied is M. mazeii. Multispecies multicellular structures are formed by a variety of archaeal organisms, which are either flat (biofilm) or globular (granule) and constitute a functional association or consortium. Details of morphology, formation, and internal organization are described for representative examples of multicellular structures. These may be seen as the result of primitive histogenesis reflecting primeval mechanisms of differentiation-development that might have evolved driven by environmental stressors. Cells in these complex threedimensional arrangements are not only positioned so they can interact with each other for more efficient functioning as in a tissue or organ, but are also protected from stressors. Single cells lacking the protective shield of other cells packed together with intercellular connective material, which is typical of multicellular structures, are directly exposed to environmental stressors and, thus, are at a disadvantage from the evolutionary standpoint. It seems reasonable to argue that differentiation-development leading to histogenesis might have arisen in primeval times as a consequence of the harsh conditions that primitive life forms had to endure, and that the ability to form tissue-like structures was a primary characteristic that ensured positive selection.

Prostaglandin E 1-Induced Deconsolidation of Thrombin-Activated Platelet Aggregates I : Ultrastructure-Computer Image Analysis

We have compared, at an ultrastructural-computer image morphometric level, the relaxation induced by Mg-ethylene-bis-oxyethylenenitrilo-tetracetic acid and prostaglandin E 1 on a model of a thrombin-activated platelet aggregate. Mg-ethylene-bis-oxyethylenenitrilo-tetracetic acid produced a small increase of 5.0% of the intercellular space over the control levels, and a decrease of 10.0±1.3% of the cross-sectional area of the platelets, with no apparent cytoskeletal alterations. In contrast, the prostaglandin E 1-treated preparation shows a 360% increase in the intercellular space and a decrease of the average platelet cross-sectional area of 30.0± 2.0% with marked cytoskeletal alterations. We use the term “deconsolidation” to describe this effect. The enlargement of the intercellular space allows the observation of two types of contacts: (1) a type S (segmental) complex, of approximately 200-nm length that maintains a narrow interplatelet gap of 20–30 nm, filled with a dense intercellular material, and (2) a type R (reticular) complex, formed by scant focal regions of the plasma membrane from opposing platelets that are connected through a mesh of fibrillar or granular material contained within a variable-size space. We hypothesize that deconsolidation is caused by fluid loss from the platelets into the intercellular space. As a result, platelet volume decreases and intercellular space increases.

Effect of Low-temperature Air-plasma Treatment on Wool Dyeing and Its Color Fastness.

Color fastness of a wool fabric that was low-temperature air-plasma treated and dyed with an acid dye has been evaluated. Color fading of the plasma treated fabric by carbon arc light irradiation was lesser at initial stage than that of the fabric without plasma treatment. The oxidized substrate through the plasma treatment may inhibit the photo-reduction reaction of the dye. Color fastness of the plasma treated fabric to laundering was poorer than that of untreated fabric. The phenomena may be attributed to an enhancement of dye diffusion in wool substrate by relaxation of intercellular material of wool by the plasma treatment.