Initial Differentiation of Vascular Tissue in the Shoot Apex of Carrot (Daucus carotaL.)

Although an initial stage of vascular differentiation precedingprocambium has been demonstrated in ferns, its presence in seedplants has not been accepted generally. In the shoot apex ofcarrot, a short cylinder of provascular tissue is recognizedas the initial stage of vascular differentiation. This firstbecomes apparent through the enlargement and vacuolation ofpith and cortical tissue rather than as a result of specificchanges in the provascular tissue itself. Procambium in discretestrands differentiates acropetally in the provascular tissuein relation to developing leaf primordia. Provascular tissueis not recognized above the axil of the youngest leaf primordiumbut it is distinct at or above the level at which the traceof the youngest primordium diverges. Support for the recognitionof provascular tissue is provided by a positive reaction tohistochemical tests for carboxylesterases in this tissue aswell as in procambium and later stages of vascular differentiation.Copyright1999 Annals of Botany Company. Provascular tissue, carboxylesterase, shoot apex, vascular differentiation, carrot (Daucus carotaL.).     

Gut-associated lymphoid tissue (GALT) of the goldfish,Carassius auratus

The head kidney and spleen are major sites of haemopoiesis in fish; a secondary center is found in loose connective tissue of the intestine. In this study we determined the nature of gut-associated haemopoietic tissue in the goldfish, Carassius auratus, using light and electron microscopy. This tissue is a loose stroma of reticular cells and fibers vascularized by capillaries, venules, and arterioles. The cellular population includes lymphoblasts, small and medium-sized lymphocytes, plasmocytes, macrophages, and various granulocytes. The most abundant granulocyte is the mast cell, whose large granules stain with Alcian blue and toluidine blue. Heterophils are found in the intestinal connective tissue as well as two other granulocytes: one with ovoid granules having dense parallel lamellae and another with granules containing crystalline inclusions. Immature forms of both granulocytes were also noted. Macrophages containing phagocytosed debris were often located close to the epithelium; they were observed forming clusters with lymphocytes. The epithelium contained a number of migrating leucocytes including lymphocytes and lymphoblasts, macrophages, and heterophils. Although many granulocytes were found in the connective tissue, granulopoiesis does not seem to be a major function. Gut-associated haemopoietic tissue in goldfish resembles diffuse lymphoid tissue and may be involved in intestinal immune responses.     

An Improved Protocol for the Isolation of RNA from Roots of Tea (Camellia sinensis (L.) O. Kuntze)

Tea, a beverage crop, is a rich source of polyphenols and polysaccharides which greatly attribute to its importance. However, oxidation and precipitation of these compounds during nucleic acids extraction is a limitation to molecular biology and genomic studies. On isolation of total RNA from root tissue using established protocols, difficulties were encountered in terms of purity and quantity of isolated RNA or some of the methods were time-consuming and also yields were low. The present communication combines a phenol-based RNA isolation protocol with a cetyltrimethylammonium bromide-based procedure with appropriate modifications. This protocol successfully isolated RNA from tap root tissue in 2-3 h as compared with 16 h reported by the previous method. Also, RNA yield was higher by more than fourfold. The RNA isolated by this protocol was successfully used for downstream applications such as RT-PCR and the construction of suppression subtractive hybridization library. The developed protocol worked well with other plant tissue with high polyphenols and polysaccharides contents.     

Cortical tissue-specific accumulation of the root-specific ns-LTP transcripts in the bean (Phaseolus vulgaris) seedlings

The characterization of a cDNA clone encoding non-specific lipid transfer protein (PvLTP, formerly named PVR3) in the roots of bean seedlings has been previously reported. In this study, we examined the temporal and spatial accumulation of PvLTP mRNA and the effect of the auxin naphthaleneacetic acid (NAA) on the accumulation of PvLTP mRNA during root development. In situ hybridization showed that accumulation of PvLTP mRNA is highly tissue-specific. Accumulation was detected in the cortical tissue, but not in other tissues of root, including the quiescent center and root cap. Within the cortical tissue, accumulation of PvLTP mRNA was developmentally regulated; accumulation of PvLTP mRNA was high in the cortical tissue of the proximal and ground meristem and declined as cortical tissue developed further. Since the appropriate distribution of auxin is an important factor responsible for the maintenance of root meristem organization. We examined effect of auxin on the accumulation of PvLTP mRNA in relation to the development of cortical tissue. In bean seedlings grown on medium supplemented with 5 M NAA, morphological alternations, including radial root expansion and abnormal tissue organization in the root apical meristem, were observed. Only faint accumulation signals of PvLTP mRNA were observed in the cortical tissue of proximal meristem region, indicating that cortical tissue development was repressed by exogenous NAA. However, our results suggest that the change in accumulation of PvLTP mRNA is not direct regulatory effect but reflective effect of altered development of cortical tissue that was induced by exogenous NAA. The temporal and spatial accumulation of PvLTP mRNA indicates that PvLTP is a useful marker for the development of cortical tissue in the root tip in bean seedlings.     

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Asia and the Pacific and the Latin American regions

The technical assistance program of the International Atomic Energy Agency (IAEA) for its member states in the framework of the implementation of its program on radiation and tissue banking focuses on ensuring the availability of quality radiation-sterilised tissue grafts. The IAEA also helps its member states to develop quality control capabilities in order to ensure the safe use of the processed tissues in certain medical treatments. The majority of developing countries does not have such capacity, and must import expensive sterilised tissues from developed countries. The IAEA’s core contribution to its program on radiation and tissue banking in Asia and the Pacific and the Latin American regions is a technology for sterilisation by gamma radiation and a training program for tissue bank operators and medical personnel. The Agency develops capabilities for radiation sterilisation of tissue grafts, both for reducing the pre-processing bacterial load, and as a terminal sterilisation process. Sterilising tissue grafts offers a clear advantage in terms of safety. Moreover, compared to alternative sterilisation methods, radiation sterilisation is considered particularly safe in relation to environmental concerns, and the deposition of harmful residuals in the tissue, which occurs for example in the use of chemical such as ethylene oxide gas. Radiation sterilisation, thus, has become the method of choice for an increasing number of tissue banks. Radiation sterilisation of tissue grafts is a critical component in the chain connecting donors to recipients of high quality tissue grafts. Due to this fact, the IAEA has evolved as the only organisation in the UN System with expertise related to tissue banking.     

Extraintestinal gamogony of Aggregata octopiana in the reared common octopus (Octopus vulgaris) (Cephalopoda: Octopodidae)

Aggregata octopiana (Apicomplexa, Aggregatidae) is the most prevalent coccidian in the wild common octopus (Octopus vulgaris), whose heteroxenous life cycle includes gamogony and sporogony undergoing in the octopus digestive tract. In the infected reared octopi, we observed an unusual extraintestinal distribution of the coccidian, with both gamogony and sporogony ongoing in dermal and gill tissue. Oocysts and macrogamonts were embedded in the dermal connective tissue of octopian arms, demarcated by a thin cyst wall or multilayered dark membrane. In gill connective and epithelial tissue all developmental stages were observed, eliciting hemocytic infiltration. Sometimes a complete substitution of the tissue by cysts and developmental stages occurred, resulting in necrosis of gill tissue.     

Reconstruction of absorbed doses to fibroglandular tissue of the breast of women undergoing mammography (1960 to the present)

The assessment of potential benefits versus harms from mammographic examinations as described in the controversial breast cancer screening recommendations of the U.S. Preventive Task Force included limited consideration of absorbed dose to the fibroglandular tissue of the breast (glandular tissue dose), the tissue at risk for breast cancer. Epidemiological studies on cancer risks associated with diagnostic radiological examinations often lack accurate information on glandular tissue dose, and there is a clear need for better estimates of these doses. Our objective was to develop a quantitative summary of glandular tissue doses from mammography by considering sources of variation over time in key parameters, including imaging protocols, X-ray target materials, voltage, filtration, incident air kerma, compressed breast thickness, and breast composition. We estimated the minimum, maximum and mean values for glandular tissue dose for populations of exposed women within 5-year periods from 1960 to the present, with the minimum to maximum range likely including 90% to 95% of the entirety of the dose range from mammography in North America and Europe. Glandular tissue dose from a single view in mammography is presently about 2 mGy, about one-sixth the dose in the 1960s. The ratio of our estimates of maximum to minimum glandular tissue doses for average-size breasts was about 100 in the 1960s compared to a ratio of about 5 in recent years. Findings from our analysis provide quantitative information on glandular tissue doses from mammographic examinations that can be used in epidemiological studies of breast cancer.     

The role of the epithelial-to-mesenchymal transition (EMT) in diseases of the salivary glands

The link between inflammatory microenvironment and cancer emerged in the last years as a decisive factor in the induction of the pathological epithelial–mesenchymal transition (EMT). The EMT induces changes of cell states converting the epithelial cells to mesenchymal cells when this program is fully executed and EMT has emerged as a central driver of tumor malignancy. Cellular pathways activated by chronic inflammation brought about by chronic infections, by immune-mediated diseases, or by dysregulated wound healing at sites of repetitive tissue injury, constitute risk factors or initial cell transformation and for cancer progression. EMT and its intermediate states have recently been identified as crucial inducers of organ fibrosis, inflammation and tumor progression. In this review, we discuss the current state-of-the-art and latest findings regarding the link between EMT, inflammation, fibrosis and cancer, highlighting the most recent data on EMT-dependent tissue fibrosis during chronic inflammatory salivary glands conditions and salivary glands tumors.     

Methods for the analysis of the composition of bone tissue, with a focus on imaging mass spectrometry (TOF-SIMS)

The review describes methods available for analyzing mineralization of bone tissue in healing of fractures and implants in bone. The recent development of imaging MS, TOF-secondary ion MS (SIMS), enabling localization of hydroxyapatite (HA) in tissue samples will be presented in some detail. We strongly believe that imaging MS has the potential of becoming an important method for the studies of bone mineralization. Formation and mineralization of bone tissue with HA is a process controlled by cells, the osteoblasts, osteocytes, and osteoclasts. Formation, de novo, of bone in embryonic tissue takes place in extracellular areas within cell clusters that regulate the environment of the mineralization zone. The process of de novo formation of bone as in embryonic tissue is reactivated in adults for example during fracture healing, with or without the presence of bone implants. Thus, bone healing is one of few examples of scar-free healing of a differentiated tissue. Much of the interest of researchers in bone mineralization stems from a desire to influence the process of bone formation towards fast and endurable bone healing. There is also a wish to understand the pathogenesis of bone diseases, for example osteogenesis imperfecta, Turner's syndrome and osteoporosis.     

An immunohistochemical study on the postnatal development of rat nasal-associated lymphoid tissue (NALT)

Summary This study concerns the development of nasal-associated lymphoid tissue in the rat, using immuno- and enzyme-histochemical staining techniques on cryostat sections. Nasal-associated lymphoid tissue is present at birth as a small accumulation of mainly T lymphocytes and non-lymphoid cells; B cells are rare. Distinct areas of T and B cells appear at 10 days after birth; by that time high endothelial venules are also observed. Intra-epithelial lymphocytes are present, most of them being T-helper cells. ED1+ macrophages are seen throughout the tissue. The proportion of ED1+cells does not change during ontogeny. ED2+cells (tissue macrophages) are present predominantly at the border between the lymphoid tissue and the surrounding connective tissue, in all age-groups. ED3+mononuclear cells are scattered throughout the nasal-associated lymphoid tissue of young animals. Later on, the ED3+ cells migrate into the border-area between lymphoid and connective tissue. Ia+ non-lymphoid cells in the nasal lymphoid tissue increase in number during ontogeny. Only a few of them show acid phosphatase activity, indicating that the proportion of classical scavenger macrophages is low. Some of them may be antigen presenting (dendritic) cells. Ia+ dendritic cells also occur between the epithelial cells. Moreover, some epithelial cells express the Ia marker.     

Development of the swimbladder in the European eel (Anguilla anguilla)

The swimbladder of the adult eel, Anguilla anguilla, with its bipolar countercurrent system, the rete mirabile, is a widely used model for swimbladder function, but very little is known about the development of this swimbladder. Our histological studies on the developing swimbladder revealed that during metamorphosis the swimbladder becomes present as a dorsal outgrowth of the esophagus. It is filled with surfactant, and gas was not detected in the swimbladder. In the young glass-eel, the epithelial (gas gland) cells of the swimbladder are columnar, but do not yet have the typical basolateral labyrinth established in adult animals. Few blood vessels are found in the swimbladder tissue, and the submucosa is present as a thick layer of connective tissue, giving a large diffusion distance between blood vessel and swimbladder lumen. Within the next 2 or 3 months of development, gas gland cells develop their typical basolateral labyrinth, and the thickness of the submucosa is significantly reduced, resulting in a short diffusion distance between blood vessels and the swimbladder lumen. The first filling of the swimbladder with gas is observed while the gas gland cells are still in a poorly differentiated status and it appears unlikely that these cells can accomplish their typical role in gas deposition. The presence of small gas bubbles in the swimbladder as well as in the ductus pneumaticus at the time of initial swimbladder inflation suggests that the swimbladder is filled by air gulping or possibly by taking up gas bubbles from the water.     

Tailoring the degradation of hydrogels formed from multivinyl poly(ethylene glycol) and poly(vinyl alcohol) macromers for cartilage tissue engineering

Tuning the degradation profiles of polymer cell carriers to match cell and tissue growth is an important design parameter for (cartilage) tissue engineering. In this study, degradable hydrogels were fabricated from divinyl, tetrafunctional poly(ethylene glycol) (PEG) and multivinyl, multifunctional poly(vinyl alcohol) (PVA) macromers to form homopolymer and copolymer gels. These gels were characterized by their volumetric swelling ratio and mass loss profiles as a function of degradation time. By variation of the macromer chemistry and functionality, the degradation time changed from less than 1 day for homopolymer PVA gels to 34 days for pure PEG gels. Furthermore, the degrading medium influenced mass loss, and a marked decrease in degradation time, from 34 to 12 days, was observed with the PEG gels when a chondrocyte-specific medium containing fetal bovine serum was employed. Interestingly, when copolymer gels of PEG and PVA were formed, PVA was released throughout the degradation (as determined by gel permeation chromatography) suggesting that covalent cross-linking of the PVA in the network was facilitated by copolymerizing with the PEG macromer. To assess these novel gels for cartilage tissue engineering applications, chondrocytes were photoencapsulated in the copolymer networks and cultured in vitro for up to 6 weeks. DNA, glycosaminoglycan (GAG), and total collagen contents increased with culture time, and the resulting neocartilaginous tissue at 6 weeks was homogeneously distributed as seen histologically. Biochemical analysis revealed that the constructs were comprised of 0.66 +/- 0.04 microg of DNA/mg wet weight (ww), 1.0 +/- 0.05% GAG/ww, and 0.29 +/- 0.07% total collagen/ww at 6 weeks. Furthermore, the compressive modulus increased during culture from 7 to 97 kPa as the neocartilaginous tissue evolved and the gel degraded. In summary, fabricating hydrogels through the copolymerization of PEG and PVA macromers is an effective tool for encapsulating chondrocytes, controlling gel degradation profiles, and generating cartilaginous tissue.     

番红花组织内氨基酸组成

番红花（ＣｒｏｃｕｓＳａｔｉｖｕｓ）为鸢尾科多年生草本植物。自古以来它为妇科、伤科的良药。主要研究了番红花组织内氨基酸成分及必需氨基酸,其蛋白质高达２０％以上,而必需氨基酸占总氨基酸含量的５０％以上,这对医学、营养科学有很高的研究价值。     

On the median pharyngeal valve of the American alligator (Alligator mississippiensis)

The middle ear cavities of crocodilians have complex connections with the pharyngeal lumen, including lateral and median components which both open into a single chamber located on the dorsal midline of the pharynx. This chamber and the surrounding soft-tissue is herein termed the median pharyngeal valve. In the American alligator (Alligator mississippiensis) this valve opens, for a duration of 0.3 s, approximately every 120 s; the patency of the median pharyngeal valve was not influenced by either auditory stimuli or by submersing the alligator underwater. The median pharyngeal valve has an outer capsule of dense connective tissue and fibrocartilage and an inner “plug” of loose connective tissue. These opposing surfaces are lined by respiratory epithelium and separated by a cavity that is continuous with the middle ear cavities and the pharyngeal lumen (through a central opening in the capsule termed the pore). The inner plug of the median pharyngeal valve is contacted by skeletal muscles positioned to serve as both elevators/retractors (which would open the valve) and elevators/protractors (which, in conjunction with gravity, would close the valve). Unlike other vertebrate valve systems, the median pharyngeal valve appears to function as a deformable ball check valve.     

Historical aspects of protandrous sex change in the anemonefish Amphiprion melanopus (Pomacentridae, Teleostei)

Gonadal structure and cellular composition were examined in juveniles, males and females of the protandric hermaphrodite, Amphiprion melanopus. Functional sex change was experimentally induced in the field and gonad structure was histologically examined both qualitatively and quantitatively at 10, 20, 30 and 45 days after its initiation. Juvenile gonads consist primarily of immature ovarian tissue. Functional male gonads are ovotestes with co-existing mature spermatogenic tissue and immature ovarian tissue, while females possess only ovarian tissue. The initiation of sex change is marked by a rapid maturation of spermatogenic tissue and proliferation of putative oogonia. Gonads were essentially female by 20 days into sex change, but evidence of mature female function (marked by the initiation of vitellogenesis) was not observed until 45 days. Considerable variation between individuals was seen in quantitative measures of gonadal change in the early stages of sex change, but not in later stages. Progress in sex change as indicated by histological indicators was, however, consistent within stages. Duet systems for gamete transport changed from the male to the female form after all male tissue had been replaced.     

Histopathology of the mangrove land crab Ucides cordatus (Ocypodidae) affected by lethargic crab disease

Lethargic crab disease (LCD) has caused extensive epizootic mortality of the mangrove land crab Ucides cordatus (Linnaeus 1763) (Brachyura: Ocypodidae) along the Brazilian coast. Direct culture of tissue samples from sick crabs and subsequent isolation and purification identified the causative agent as an Exophiala species of fungus. The histopathology of crabs with variable signs of LCD indicates that the most affected tissues are the epidermis, connective tissue, heart, hepatopancreas, nervous system, and gills. Gonads, somatic muscles, and digestive system are less affected by the fungus. The observed pathology is compatible with the clinical signs of LCD. Necrosis, tissue degeneration, and congestion of hemal sinuses and vessels are present in heavily infected organs. Nerve fibers may be compressed by accumulations of yeast-like cells. In heavy infections the tissue of gill lamellae is destroyed with subsequent dilation or compression. Cellular immune responses include hemocytic infiltration, agglutination and encapsulation, and phagocytosis. Phagocytosis of yeast-like cells is abundant in the connective tissue associated with the exoskeleton. These results indicate that LCD is the result of a systemic phaeohyphomycosis caused by a species of Exophiala. The present study also suggests that dispersal of the fungus within the crab occurs through the hemal system.     

Homology Assessment of the Boundary Tissue in Fruiting Bodies of the Lichen Family Sphaerophoraceae (Lecanorales, Ascomycota)

Abstract: The ascoma ontogeny of the family Sphaerophoraceae is reviewed. The development of the boundary tissue in Leifidium tenerum is described and compared with similar structures in some other mazaediate representatives of the family ( Sphaerophorus globosus, Bunodophoron dodgei and B. diplotypum ), and with the non-mazaedia-producing genera Austropeltum and Neophyllis. The dominant structure in the base of mature ascomata in all genera is a boundary tissue forming the border between ascomatal ("generative") and thalline ("vegetative") tissue. In the mazaedia-forming genera, the boundary tissue is composed of two layers. The upper layer is a zone of ascogenous hyphae, homologous to similar zones in Neophyllis and Austropeltum. The lower layer is a pseudoparenchymatic and often strongly pigmented zone formed by generative tissue, homologous to a zone of generative tissue present in Neophyllis but lacking in Austropeltum.     

Interrelationships between developing oocytes and ovarian tissues in the chiton Sypharochiton septentriones (Ashby) (Mollusca, Polyplacophora)

Oogenesis and the relationships between oocytes and other ovarian tissues have been studied in Sypharochiton septentriones. The ovarian tissues were examined by electron microscopy and by histochemical methods. The sac-like ovary is dorsal, below the aorta, and opens to the exterior by two posterior oviducts. Ventrally, the ovarian epithelium is folded inwards to form a series of plates of tissue, which support the developing ova. Each ovum is attached to a tissue plate by a stalk, the plasma membrane of which is bathed by the blood in the tissue plate sinus. Dorsally, ciliated vessels from the aorta enter the ovary and open into blood sinuses in the top of the plates. After each germinal epithelial cell rounds up to become a primary oogonium, it undergoes four mitotic divisions to give rise to a cluster of 16 secondary oogonia. Of these, the outer ones become follicle cells and the inner ones become oocytes. As in other molluses, the increases in nuclear and nucleolar volume are relatively greatest towards the end of previtellogenesis, when chromosomal and nucleolar activity are most intense. This phase of activity is accompanied by a great increase in cytoplasmic basophilia. Subsequently this basophilia is decreased during vitellogenesis, when chromosomal and nucleolar activity diminish. Fluid filled interstices appear in the cytoplasm during early vitellogenesis. Protein yolk deposition is associated with these interstices, but the lipid yolk appears to arise de novo. The follicle cells do not appear to be directly involved in oocyte nutrition. At times during oogenesis, certain manifestations of polarity can be found in the oocyte. This polarity is based on an apical-basal axis and can be related to the nutritive source of the oocyte, namely the blood which bathes the plasma membrane of the oocyte in the stalk. Numerous granulated cells are present in the ovarian tissue plates and ventral epithelium as storage cells containing lysosomes, and they are capable of phagocytosis and micropinocytosis of extracellular material. A scheme is outlined whereby reserves in these cells may be incorporated into the oocyte cytoplasm. Lysosomal activity is responsible for autolysis of the cells as well as resorption of unspawned ova.