Cuticular ultrastructure of Chordodes nobilii Camerano, 1901, with a comparison of cuticular ultrastructure in horsehair worms (Nematomorpha)

The cuticle of Chordodes nobilii Camerano, 1901 is composed of a proximal layer with about 30 sheets of large fibers in alternating orientations and a distal layer, which mainly forms the surface structures, the areoles. The three different types of areoles, simple, tubercle and crowned areoles, are formed mainly by material of strong and medium electron density. The tubercle areoles have a basal constriction and paired spherical structures of unknown function below the base. Irregularly distributed are paired, cushion-like structures, from which projections traverse the cuticle and run into the epidermis. In the crowned areoles, these cushions also send projections into the apical filaments. A comparison with the few ultrastructurally described cuticles from other species reveals some similarities between the cuticles of C. nobilii and Paragordius varius, making it probable that the cushion-like structures are homologous. However, Pseudochordodes bedriagae, which is more closely related to Chordodes than Paragordius, lacks the cushions. Problematic is the interpretation of different cuticular structures in Gordius. If correctly determined, areoles are present in some Gordius species and resemble in their structure areoles from other species. If areoles have to be regarded as homologous, the absence of a distal layer and areoles would have to be interpreted as a secondary reduction in species such as Gordius aquaticus.     

Novel hybrid scaffolds for the cultivation of osteoblast cells

In this study, natural biodegradable polysaccharide, chitosan, and synthetic biodegradable polymer, poly(?-caprolactone) (PCL) were used to prepare 3D, hybrid polymeric tissue scaffolds (PCL/chitosan blend and PCL/chitosan/PCL layer by layer scaffolds) by using the electrospinning technique. The hybrid scaffolds were developed through HA addition to accelerate osteoblast cell growth. Characteristic examinations of the scaffolds were performed by micrometer, SEM, contact angle measurement system, ATR-FTIR, tensile machine and swelling experiments. The thickness of all electrospun scaffolds was determined in the range of 0.010 ± 0.001-0.012 ± 0.002 mm. In order to optimize electrospinning processes, suitable bead-free and uniform scaffolds were selected by using SEM images. Blending of PCL with chitosan resulted in better hydrophilicity for the PCL/chitosan scaffolds. The characteristic peaks of PCL and chitosan in the blend and layer by layer nanofibers were observed. The PCL/chitosan/PCL layer by layer structure had higher elastic modulus and tensile strength values than both individual PCL and chitosan structures. The layer by layer scaffolds exhibited the PBS absorption values of 184.2; 197.2% which were higher than those of PCL scaffolds but lower than those of PCL/chitosan blend scaffolds. SaOs-2 osteosarcoma cell culture studies showed that the highest ALP activities belonged to novel PCL/chitosan/PCL layer by layer scaffolds meaning better cell differentiation on the surfaces.     

Cranial meninges of goldfish: age-related changes in morphology of meningeal cells and accumulation of surfactant-like multilamellar bodies

In the optic tectum of goldfish, the outer, middle and inner layers of the endomeninx were evident in animals ranging in age from 1 month to several years. The outer layer in young animals consisted of closely overlapping cells with intertwined processes, whereas in the older animals it contained large extracellular spaces. The intermediate layer cells were always arranged in a single continuous layer, but in young animals they overlapped extensively with one another toward their edges whereas in the oldest animals they became extremely flat and non-overlapping. The inner layer included an outer tier of cells with their bases adhering to the intermediate layer, and an inner tier of cells detached from both the intermediate layer and the basal lamina overlying the brain parenchyma. Inner layer cells contained many large vacuoles that were in continuity with the extracellular space. With age, the extracellular space and the vacuolar system expanded, and the inner layer evolved into a meshwork of attenuated cytoplasmic processes embedded in the granular extracellular matrix. Another age-related feature was the accumulation adjacent to the basal lamina of uniform disc-shaped membranous structures, resembling multilamellar bodies of lung surfactant. These disc bodies were apparently generated by the coalescence of vesicles formed at the surface of the inner layer cells, possibly as a by-product of protein secretion by these cells.     

Three-dimensional structure of the regular tetragonal surface layer of Azotobacter vinelandii.

Fragments of the Azotobacter vinelandii tetragonal surface (S) layer, free of outer membrane material, were obtained by treating whole cells with 100 microM EDTA. The three-dimensional structure of the S layer was reconstructed from tilted-view electron micrographs of the S-layer fragments, after computer-assisted image processing by correlation averaging. At a resolution of 1.7 nm, the S layer exhibited funnel-shaped subunits situated at one fourfold-symmetry axis and interconnected at the other fourfold-symmetry axis to form prominent cruciform linking structures. These data, in conjunction with a relief reconstruction of the surface of freeze-etched whole cells, indicated that the apex of the funnel-shaped subunit was associated with the outer membrane, while the funnel "opening" faced the environment; the cruciform linking structures were formed at the outermost surface of the S layer. Electron microscopy and image enhancement were used to compare the structure of the outer membrane-associated S layer with that of fragments of the S layer dislodged from the outer membrane. This analysis revealed an increase in the lattice constant of the S layer from 12.5 to 13.6 nm and an alteration in the position of the cruciform linking structures in the z direction. These conformational changes resulted in a reduction in the thickness of the S layer (minimum estimate, 5 nm) and an apparent increase in the size of the gaps between the subunits. In terms of the porosity of the S layer, this gave the appearance of a transition from a closed to a more open structure.     

Carapace formation of the podocopid ostracode Semicytherura species (Crustacea: Ostracoda)

Details of ostracode carapace structures were examined by SEM and TEM. The podocopine ostracode Semicytherura kazahana has major ridges on the carapace surface and develops its prismatic layer inside the adult carapace. Electron microscopy at the final molt reveals that the major ridges arise from the highly dense formation of pits within the underlying swollen epidermis, and that disappearance of the epidermis in the presumptive area of the prismatic layer occurs after the calcification of the outer lamella cuticle, and just before synthesis of the membranous layer. These facts suggest that the formation of the carapace in Semicytherura takes place via a more complex process than that of the other podocopid ostracodes.     

第一类鱼抗冻蛋白对冰晶生长界面层结构的影响

根据冰晶在水溶液中生长的基本热力学性质,应用多层界面模型,分别得到了冰晶在纯水及抗冻蛋白溶液中生长界面层的吉布斯自由能.由冰晶生长界面层的吉布斯自由能,分析了冰晶在三种不同第一类鱼抗冻蛋白分子溶液中,热平衡状态下生长界面层的微观平衡结构,发现冰晶在抗冻蛋白溶液中生长与其在纯水中生长相比,界面层结构有明显变化,结合抗冻蛋...     

Ultrastructural changes in the proper layer of the mucous membrane of the duodenum following general gamma-irradiation]

The work has been performed on mature male Wistar rats which were irradiated in a "Gamma-Sell-220" apparatus in the dose of 1000 r, with thepower 42 r/sec. It has been shown that in early terms after irradiation (1-6 hours) slightly pronounced destructive changes were observed in cellular and fibrous structures of the stroma of theproper layer of the duodenum membrane in addition to pronounced exudative changes. Further, the latter increased and became maximum within 24 hours. The edema extends into the basal part of enterocytes and between the stroma cells giving rize to desorganization of all mucous membran elements. Seventy two hours after irradiation the destructive changes in cellular and fibrous structures of the mucous membrane layer proper became predominant. The authors make a conclusion that the changes in the stroma aggravate dysfunction of the epithelium injured by the irradiation energy.     

Deposition of pectin/poly-L-lysine multilayers with pectins of varying degrees of esterification

The effect of pectin esterification on the assembly of multilayers consisting of poly-L-lysine (PLL) and pectin was studied using surface plasmon resonance (SPR), Fourier transform infrared-attenuated total reflection spectroscopy (FTIR-ATR), and a quartz crystal microbalance with dissipation monitoring (QCMD). With each layer deposited, there was a progressive increase in mass. The net charge of the multilayers was positive and increased with increasing degree of esterification of the pectin. Multilayer fabrication involved a limited fractionation of the pectin preparations, with the more highly esterified pectins having a weaker affinity for PLL. The multilayers were relatively hydrated structures with estimates of solids content in the range 10-32% w/w. The more highly esterified pectins had a tendency to form more hydrated structures, which showed a strong deswelling when PLL was added to a freshly deposited pectin layer.     

中亚热带地区两种森林植被类型土壤微生物群落结构

利用磷脂脂肪酸(PLFA)生物标记法分析了中亚热带地区罗浮栲天然林和相邻的杉木人工林土壤微生物群落结构特点.结果表明: 两种植被类型的磷脂脂肪酸总量、细菌特征脂肪酸、真菌特征脂肪酸、放线菌特征脂肪酸、革兰氏阳性菌和革兰氏阴性菌特征脂肪酸含量均为0～10 cm高于10～20 cm土层,罗浮栲天然林高于杉木人工林.在两种植被类型的两个土层中,细菌PLFAs含量均显著高于真菌PLFAs含量.两种植被类型中,细菌PLFAs含量约占PLFAs总量的44%～52%,而真菌仅占6%～8%,表明细菌在该地区两种植被类型土壤中处于优势地位.主成分分析表明,土壤微生物群落结构差异主要由植被类型差异引起,土层深度的影响相对较小.相关分析显示,革兰氏阴性菌、革兰氏阳性菌以及细菌的PLFAs含量与pH呈显著负相关,与含水量呈显著正相关;土壤微生物主要类群PLFAs含量与总氮、有机碳、C/N和铵态氮均呈显著正相关.     

An assessment of the models of thin filament of the sarcomere using small-angle X-ray data on rabbit relaxed muscle

Models of a thin filament based on various G-actin atomic structures and modes of their packing into helical structures were considered. The calculated intensities of actin layer lines were compared with the X-ray data for thin fiber bundles of a relaxed rabbit skeletal muscle. The effect of the main components of thin filament on the intensity of actin layer lines was also analyzed. The F-actin PDB 3BYH model gave the best fit to the experimental data.     

Reduction of adhesions with composite AlloDerm/polypropylene mesh implants for abdominal wall reconstruction

Ventral hernia repair often includes the use of structural prosthetic materials, such as polypropylene mesh, that can induce dense abdominal adhesions to peritoneal structures. AlloDerm (LifeCell Corp., Branchburg, N.J.), a commercially available decellularized human dermal analogue with its native basement membrane components intact, is gradually revascularized and replaced with autologous tissue after implantation. The authors hypothesized that AlloDerm integrated with polypropylene mesh would reduce adhesions and provide a biodegradable scaffold to generate an autologous vascularized tissue layer separating the abdominal viscera from the mesh. Ventral hernia defects (3 x 1 cm) in 19 guinea pigs were repaired using an inlay technique with polypropylene mesh alone (n = 6) or with composite implants constructed by integrating polypropylene mesh and AlloDerm with its basement membrane surface oriented toward (polypropylene/AlloIn, n = 7) or away from (polypropylene/ AlloOut, n = 6) the peritoneal cavity. At 4 weeks, the authors determined the amount of mesh implant surface area covered by adhesions, the strength of the adhesions [graded from 0 (none) to 3], and the incidence of bowel adhesions. Histologic analyses were performed on full-thickness tissue sections from the repair sites. The mean surface areas affected by adhesions and mean adhesion strength were significantly lower in the polypropylene/AlloIn (area, 12.4 percent; mean grade, 1.0) and polypropylene/AlloOut (area, 9.5 percent; mean grade, 0.5) groups than in the polypropylene group (area, 79.5 percent; mean grade, 2.9); there were no such differences between the polypropylene/AlloIn and polypropylene/AlloOut groups. The bowel was adherent to 67 percent of polypropylene repairs and 0 percent of the composite mesh repairs. The AlloDerm was remodeled to form a vascularized tissue layer beneath the mesh in composite repairs, unlike the significantly thinner, dense scar layer that formed in the polypropylene repairs. Immunohistochemical labeling for factor VIII showed neovascularization throughout the AlloDerm.The AlloDerm thus functioned as a biodegradable tissue scaffold, guiding the formation of a thick, well-vascularized tissue layer separating the polypropylene mesh from intraperitoneal structures. This significantly reduced both the amount of surface area covered by adhesions and adhesion strength. Basement membrane orientation had no effect. Composite mesh implants composed of structural prosthetic materials integrated with AlloDerm may have useful clinical applications for abdominal wall reconstruction by reducing adhesions and providing a vascularized tissue layer to separate and protect the peritoneal structures from polypropylene mesh fibers.     

Targeted disruption of the mouse rho-associated kinase 2 gene results in intrauterine growth retardation and fetal death

Rho-associated kinase (ROCK), including the ROCK-I and ROCK-II isoforms, is a protein kinase involved in signaling from Rho to actin cytoskeleton. However, in vivo functions of each ROCK isoform remain largely unknown. We generated mice deficient in ROCK-II by gene targeting. ROCK-II(-/-) embryos were found at the expected Mendelian frequency until 13.5 days postcoitum, but approximately 90% died thereafter in utero. ROCK-II(-/-) mice of both genders that survived were born runts, subsequently developed without gross abnormality, and were fertile. Whole-mount staining for a knocked-in lacZ reporter gene revealed that ROCK-II was highly expressed in the labyrinth layer of the placenta. Disruption of architecture and extensive thrombus formation were found in the labyrinth layer of ROCK-II(-/-) mice. While no obvious alteration in actin filament structures was found in the labyrinth layer of ROCK-II(-/-) placenta and stress fibers were formed in cultured ROCK-II(-/-) trophoblasts, elevated expression of plasminogen activator inhibitor 1 was found in ROCK-II(-/-) placenta. These results suggest that ROCK-II is essential in inhibiting blood coagulation and maintaining blood flow in the endothelium-free labyrinth layer and that loss of ROCK-II leads to thrombus formation, placental dysfunction, intrauterine growth retardation, and fetal death.     

Understanding Molecular Structures of Buried Interfaces in Halide Perovskite Photovoltaic Devices Nondestructively with Sub‐Monolayer Sensitivity Using Sum Frequency Generation Vibrational Spectroscopy

As performance of halide perovskite devices progresses, the device structure becomes more complex with more layers. Molecular interfacial structures between different layers play an increasingly important role in determining the overall performance in a halide perovskite device. However, current understanding of such interfacial structures at a molecular level nondestructively is limited, partially due to a lack of appropriate analytical tools to probe buried interfacial molecular structures in situ. Here, sum frequency generation (SFG) vibrational spectroscopy, a state‐of‐the‐art nonlinear interface sensitive spectroscopy, is introduced to the halide perovskite research community and is presented as a powerful tool to understand molecule behavior at buried halide perovskite interfaces in situ. It is found that interfacial molecular orientations revealed by SFG can be directly correlated to halide perovskite device performance. Here how SFG can examine molecular structures (e.g., orientations) at the perovskite/hole transporting layer and perovskite/electron transporting layer interfaces is discussed. This will promote the use of SFG to investigate molecular structures of buried interfaces in various halide perovskite materials and devices in situ nondestructively with a sub‐monolayer interface sensitivity. Such research will help to elucidate structure–function relationships of buried interfaces, aiding in the rational design/development of halide perovskite materials/devices with improved performance.     

The histochemistry of complex carbohydrates in the ovarian follicles of adult mice

Summary In the ovarian follicles of adult mice, complex carbohydrate-containing structures have been studied by means of light microscopic histochemical methods. In the ovarian follicles, the zona pellucida of oocytes, follicular fluid and intercellular matrix of the granulosa layer are found to exhibit positive reactions for complex carbohydrates with 1,2-glycol and acidic groups and -D-mannosyl and -D-glucosyl residues. The present histochemical analyses have revealed that the complex carbohydrates common to the three types of the structures are hyaluronic acid, sulfated glycosaminoglycans other than isomeric chondroitin sulfates and neutral glycoproteins and that sialic acid is a particular moiety of the zona pellucida, whereas isomeric chondroitin sulfates being that of the follicular fluid and intercellular matrix of the granulosa layer. The histophysiological activities of the carbohydrate-containing structures have been discussed with special reference to their histochemical properties determined in the present study.     

Effects of Paecilomyces lilacinus protease and chitinase on the eggshell structures and hatching of Meloidogyne javanica juveniles

A serine protease and an enzyme preparation consisting of six chitinases, previously semi-purified from a liquid culture of Paecilomyces lilacinus strain 251, were applied to Meloidogyne javanica eggs to study the effect of the enzymes on eggshell structures. Transmission electron microscopic studies revealed that the protease and chitinases drastically altered the eggshell structures when applied individually or in combination. In the protease-treated eggs, the lipid layer disappeared and the chitin layer was thinner than in the control. The eggs treated with chitinases displayed large vacuoles in the chitin layer, and the vitelline layer was split and had lost its integrity. The major changes in the eggshell structures occurred by the combined effect of P. lilacinus protease and chitinases. The lipid layer was destroyed; the chitin layer hydrolyzed and the vitelline layer had lost integrity. The effect of P. lilacinus protease and chitinase enzymes on the hatching of M. javanica juveniles was also compared with a commercially available bacterial chitinase. The P. lilacinus protease and chitinase enzymes, either individually or in combination, reduced hatching of M. javanica juveniles whereas a commercial bacterial chitinase had an enhancing effect. Some juveniles hatched when the eggs were exposed to a fungal protease and chitinase mixture. We also established that P. lilacinus chitinases retained their activity in the presence of endogenous protease activity.     

The deposition and stability of pectin/protein and pectin/poly-l-lysine/protein multilayers

The sequential deposition of pectin and protein – bovine serum albumin (BSA), β-lactoglobulin (BLG) and gelatin – to form multilayer structures was examined by Fourier transform infrared-attenuated total reflection spectroscopy (FTIR-ATR) and a quartz crystal microbalance with dissipation monitoring (QCMD). With each layer deposited there was a progressive increase in mass deposited, with a more substantial deposition of protein. Pectin deposition led to a relatively hydrated, open structure which permitted binding of protein within the layer when the biopolymers carried an opposite net charge. On increasing the pH, disassembly of the structures occurred within the vicinity of the isoelectric point of the globular proteins. No disassembly was observed for the pectin/gelatin multilayer. When a globular protein was substituted for a poly-l-lysine layer in a pectin/poly-l-lysine multilayer it was displaced by the subsequent deposition of a poly-l-lysine layer, the more highly charged polycation displacing the relatively low charged polyampholyte. The pectin/poly-l-lysine/protein multilayers remained intact upon titration to pH 8.0.     

Endowing antifouling properties on metal substrata by creating an artificial barrier layer based on scalable metal oxide nanostructures

Abstract

Here, by creating different types of artificial barrier layer against bacterial attachment, anti-biofouling properties were endowed on three metallic surfaces – aluminum, stainless steel and titanium. To each metallic surface, a tailored chemical oxidation process was applied to grow scalable oxide structures with an additional appropriate coating, resulting in three different types of anti-biofouling barrier, a thin water film, an air layer and an oil layer. Fluorescence images of the attached bacteria showed that the water layer improved the anti-biofouling performance up to 8–12?h and the air layer up to 12–24?h, comparable with the lifetime of the air layer. In comparison, the oil layer exhibited the best anti-biofouling performance by suppressing the fouled area by < 10% up to 72?h regardless of the substratum type. The present work provides simple, low-cost, scalable strategies to enhance the anti-biofouling performance of industrially important metallic surfaces.

     

Three-dimensional structures of c-Kit-positive cellular networks in the guinea pig small intestine and colon

Cryosections and whole-mount preparations of the guinea pig small intestine and colon were single or double immunolabeled using the anti-c-Kit and protein gene product 9.5 antibodies. Immunolabeled specimens were observed under a confocal laser scanning microscope. The main findings of the present study are: (1) the distribution and profiles of three-dimensional structures of c-Kit-positive cellular networks in the small intestine and colon, and (2) the anatomical relations of c-Kit-positive cells to the enteric nerves in the layers. In the small intestine, c-Kit-positive cellular networks were observed at levels of the deep muscular plexus and myenteric plexus. The c-Kit-positive cellular networks ran along or overlay the nerve fibers at the deep muscular plexus, while they showed the reticular structures intermingled with the nerve elements at the myenteric plexus. In the colon, c-Kit-positive cellular networks were observed at levels of the submuscular plexus and myenteric plexus, and were further identified within the circular and longitudinal muscle layers as well as in the subserosal layer. In the circular muscle layer, c-Kit-positive cells surrounded the associated nerve fibers and extended several long processes toward the adjacent c-Kit-positive cells. The c-Kit-positive cellular networks within the longitudinal muscle layer as well as in the subserosal layer were not associated with the nerve fibers. In the layers of the intestinal wall with c-Kit-positive cells, the cellular networks of the interstitial cells were identified in ultrastructure. The characteristic profiles of c-Kit-positive cellular networks provide a morphological basis upon which to investigate the mechanisms regulating intestinal movement. Received: 14 July 1998 / Accepted: 2 September 1998     

Surface-lining layer of airways in cystic fibrosis mice

Lung disease is the major cause of death in individuals suffering from cystic fibrosis (CF), with abnormal lung-lining fluids occurring as early as early infancy. However, the precise etiology of CF lung disease is still poorly understood. We investigated the structural components of the airway surface-lining layer in targeted Cftrtm1HGU/Cftrtm1HGU mutant mice and non-CF controls. Five lungs per animal group were fixed by intravascular triple perfusion. The ultrastructure of the surface-lining layer of large and small intrapulmonary conducting airways was systematically investigated according to a standard protocol in transmission and scanning electron micrographs. In both animal groups, the surface-lining layer consisted of an aqueous phase and an osmiophilic film of variable thickness at the air-fluid interface. The aqueous phase usually did extend <1 microm beyond the uppermost tips of the epithelial cells in both animal groups. The aqueous phase of the small airways was slightly more electron dense in Cftrtm1HGU/Cftrtm1HGU than in non-CF mice. Neither the ultrastructure of the surfactant film at the air-fluid interface nor the forms assumed by the osmiophilic structures associated with surfactant turnover in the aqueous layer differed significantly in Cftrtm1HGU/Cftrtm1HGU and non-CF mice. Hence, there were no signs of any ultrastructural abnormalities in the surface-lining layer of young adult Cftrtm1HGU/Cftrtm1HGU mice before infection with CF-related pathogens.     

Calbindin D-28k-positive neurons in the rat olfactory bulb

Summary We have studied the distribution of calbindin D-28k immunoreactivity in the rat olfactory bulb using specific monoclonal antibodies and the avidin-biotin-immunoperoxidase method. The largest number of positive neurons was located in the periglomerular layer. These neurons were identified as periglomerular cells; they have been described also by other authors as calbindin-positive elements. Close to these neurons, a second population of nerve cells was identified as superficial shortaxon neurons. The remaining layers showed a smaller number of stained elements. Other labeled neurons were located along the external border of the external plexiform layer; the scarce neurons marking its internal border were identified as van Gehuchten cells. No immunoreactive structures were found in the mitral cell layer, although we observed another population of immunostained short-axon cells at its internal border. Some reactive structures, identified by us as horizontal and vertical cells of Cajal, were located in the boundary zone between the internal plexiform layer and the granule layer. In the white matter, we found a neuronal type characterized by its large size and oriented arborization of varicose dendrites.