On the ultrastructure and the supposed function of the mineralizing matrix coat of sea urchins (Echinodermata,Echinoida)

Summary Echinoderm ossicles are part of the mesenchyme. Their formation and growth, with respect to the underlying tissues, is studied using echinoid spines and teeth and applying different methods of fixation. The calcification process in echinoderms is strictly intracellular and needs (1) syncytial sclerocytes which completely enclose (2) a vacuolar cavity which in turn contains (3) an organic matrix coat. Strictly speaking, each ossicle is nothing but the calcified vacuolar space of a single syncytium of sclerocytes. In fully grown parts, however, the continuous sheath may split open and the matrix-coated mineral may come into contact with the extracellular space. According to biochemical analyses the matrix consists of insoluble components, but most (95%) of its constituents are soluble in EDTA or weak acids. If routine transmission electron microscope methods are used the soluble components are lost and the matrix at best looks electron light. If tannic acid is added to the fixative the soluble matrix components are preserved and reveal further ultrastructural details of the biomineralization process in echinoderms. The matrix coat looks extremely electron dense. Further soluble material is to be found within the vacuolar space or attached to the vacuolar surface of the cytoplasmic sheath. The results lead to the opinion that the matrix coat consists of a hydrophobic framework of insoluble components that contains soluble components which guide the Ca through pores in the hydrophobic layers into the interior of the matrix-coated space. It is only within this space that the mineral is deposited.     

Epidermolysis bullosa simplex: Expression of gelatinase activity in cultured human skin fibroblasts

We have measured the baseline level of gelatinase in fibroblast-conditioned medium from 41 Scandinavian individuals. They comprised 12 healthy persons, 11 individuals with the skin disorder dominant epidermolysis bullosa simplex (DEBS), 16 patients with other types of epidermolysis bullosa (EB) and 2 siblings with prolidase deficiency. These results divide the cell strains into those with low and those with high activity levels. Although this dual biochemical trait occurred in all the groups of individuals, the high-activity trait was more frequent among the DEBS patients. The localized DEBS forms showed an elevated activity level, in contrast to the previously reported generalized DEBS Köbner forms. Although a high level was found in some individuals with other EB forms, the high incidence in four families with localized DEBS Weber-Cockayne (eight of eight) and a single family with generalized DEBS—mottled pigmentation (two of two) may result from a close linkage between an EB gene and a gene responsible for the biochemical trait. In addition, in the single complete family tested, the level of gelatinase activity in cultured fibroblasts seemed to be regulated by codominant alleles or genes. A raised baseline level of gelatinase activity in cultured skin fibroblasts may be the result of either an altered expression of gelatinase or an allelic variant of this enzyme with increased specific activity. Further studies of gelatinase in cultured fibroblasts may provide insight into the regulatory mechanism and genetics behind this activity and allow formal linkage studies versus DEBS.This work was supported in part by the Norwegian Research Council for Science and the Humanities (NAVF) and the Concerted Action on Hereditary Connective Tissue Diseases of the European Community (1990–1992, project leader, M. Matton).Part of this work was performed at the Department of Genetics, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo.     

噬菌体φHAU3的cos位点及其与寄主相互作用的功能位点attP和attB的定位

ＨＡＵ３是寄主范围很广的放线菌噬菌体。Ｓｏｕｔｈｅｒｎ杂交实验表明,ＨＡＵ３可以整合到吸水链霉菌应城变种１０－２２和变铅青链霉菌６６的突变体ＺＸ１的染色体中,形成溶原,其溶原菌自发释放ＨＡＵ３,不受热激和紫外线照射的诱导。通过比较ＨＡＵ３衍生噬粒ｐＩＪ８３００的ＤＮＡ酶切片段在加热前、后电泳带谱的区别,将ＨＡＵ３的ｃｏｓ位点在ｐＩＪ８３００的图谱上得到了定位。还利用Ｓｏｕｔｈｅｒｎ杂交的方法定位了ＨＡＵ３与宿主形成溶原时附着位点（ａｔｔＰ）,并利用脉冲电泳技术定位了在变铅青链霉菌ＺＸ７和吸水链霉菌应城变种１０－２２中形成溶原的附着位点（ａｔｔＢ）。这些信息均有利于以ＨＡＵ３为基础的载体的发展和优化。     

Plant and algal interference in bacterial beta-D-galactosidase and beta-D-glucuronidase assays.

Several commonly occurring freshwater and marine plants and algae were screened for beta-D-galactosidase and beta-D-glucuronidase activities by using a 60-min enzyme assay based on the hydrolysis by these enzymes of 4-methylumbelliferyl-beta-D-galactoside and 4-methylumbelliferyl- beta-glucuronide, respectively. All freshwater plant extracts tested showed beta-D-galactosidase activity several at relatively high levels, and a number also showed beta-D-glucuronidase activity. A number of the macroalgae showed no activity of either enzyme, but those showing beta-D-galactosidase activity also showed beta-D-glucuronidase activity. The majority of microalgae showed some beta-D-galactosidase activity, but few showed beta-D-glucuronidase activity. Further studies, using the commercial Colilert test and the marine water formulation of Colilert, revealed that 2 of 11 of the microalgal species and several of the plant extracts tested caused positive reactions. It was concluded that several plant extracts and algae could significantly interfere with the detection of coliform bacteria and Escherichia coli with the use of rapid assays, on the basis of their production of beta-D-galactosidase and beta-D-glucuronidase, respectively. The significance of the plant and algal interferences in tests such as Colilert is dependent on the levels of enzymes released under natural conditions, the dilution which they may undergo, and the numbers of algal cells present. This also applies to interferences in rapid enzyme assays.(ABSTRACT TRUNCATED AT 250 WORDS)     

Repeated polyketide synthase modules involved in the biosynthesis of a heptaene macrolide by Streptomyces sp. FR-008

Genes for biosynthesis of a Streptomyces sp. FR-008 heptaene macrolide antibiotic with antifungal and mosquito larvicidal activity were cloned in Escherichia coli using heterologous DNA probes. The cloned genes were implicated in heptaene biosynthiesis by gene replacement. The FR-008 antibiotic contains a 38-membered, poiyketide-derived macrolide ring. Southern hybridization using probes encoding domains of the type i modular erythromycin polyketide synthase (PKS) showed that the Streptomyces sp. FR-008 PKS gene cluster contains repeated sequences spanning c. 105 kb of contiguous DNA; assuming c. 5 kb for each PKS module, this is in striking agreement with the expectation for the 21-step condensation process required for synthesis of the FR-008 carbon chain. The methods developed for transformation and gene replacement in Streptomyces sp. FR-008 make it possible to genetically manipulate polyene macrolide production, and may later lead to the biosynthesis of novel polyene macrolides.     

The effect of intrinsic curvature on supercoiling: Predictions of elasticity theory

Elasticity theory of naturally curved rods is employed to study the effects of intrinsic curvature on the properties of the equilibrium conformations of supercoiled DNA. The results stand in sharp contrast to those obtained when the molecule is viewed as being straight in its relaxed form. Starting from very fundamental principles of the theory, we show that the torsion of an open segment with a curved duplex axis can vary when the temperature, and along with it, the intrinsic twist is changed. Conversely, an imposed helicity, such as might be associated with binding to a histone, can change the intrinsic twist. It is also shown that another consequence of the presence of naturally curved sequences is that the twist density will, in general, vary with position along the chain in all equilibrium states. Then portions of the molecule will be more or less susceptible to interaction with other agents sensitive to such a variation. Finally, some closed equilibrium global structures uniquely associated with intrinsic curvature are discussed. © 1993 John Wiley & Sons, Inc.     

Projections of the guinea-pig paracervical ganglion to pelvic viscera

Summary The uterine cervix, urinary bladder and rectum of guinea pigs were injected with Fast Blue dye for retrograde transport studies. Dye-laden neuronal perikarya were detected for each viscus in the paracervical ganglion. These same perikarya also exhibited immunoreactivities for tyrosine hydroxylase, aromatic amino acid decarboxylase, dopamine -hydroxylase, neuropeptide Y, or vasoactive intestinal peptide, though the perikarya projecting to the urinary bladder did not exhibit immunoreactivity for aromatic amino acid decarboxylase. The results of this study indicate that the guinea-pig paracervical ganglion projects to viscera in addition to the uterus, and that the ganglion contains a range of immunoreactivities related to adrenergic and non-adrenergic neurotransmitters.     

Tropical dry woodland loss occurs disproportionately in areas of highest conservation value

Tropical and subtropical dry woodlands are rich in biodiversity and carbon. Yet, many of these woodlands are under high deforestation pressure and remain weakly protected. Here, we assessed how deforestation dynamics relate to areas of woodland protection and to conservation priorities across the world's tropical dry woodlands. Specifically, we characterized different types of deforestation frontier from 2000 to 2020 and compared them to protected areas (PAs), Indigenous Peoples' lands and conservation areas for biodiversity, carbon and water. We found that global conservation priorities were always overrepresented in tropical dry woodlands compared to the rest of the globe (between 4% and 96% more than expected, depending on the type of conservation priority). Moreover, about 41% of all dry woodlands were characterized as deforestation frontiers, and these frontiers have been falling disproportionately in areas with important regional (i.e. tropical dry woodland) conservation assets. While deforestation frontiers were identified within all tropical dry woodland classes of woodland protection, they were lower than the average within protected areas coinciding with Indigenous Peoples' lands (23%), and within other PAs (28%). However, within PAs, deforestation frontiers have also been disproportionately affecting regional conservation assets. Many emerging deforestation frontiers were identified outside but close to PAs, highlighting a growing threat that the conserved areas of dry woodland will become isolated. Understanding how deforestation frontiers coincide with major types of current woodland protection can help target context-specific conservation policies and interventions to tropical dry woodland conservation assets (e.g. PAs in which deforestation is rampant require stronger enforcement, inactive deforestation frontiers could benefit from restoration). Our analyses also identify recurring patterns that can be used to test the transferability of governance approaches and promote learning across social–ecological contexts.     

Intratumoral interleukin-2 immunotherapy: Activation of tumor-infiltrating and splenic lymphocytes in vivo

Direct intratumoral injection of interleukin-2 (IL-2) was evaluated in a murine model. Balb/c mice received 5 × 10⁴ Line 1 alveolar carcinoma cells (L1C2) by subcutaneous injection. On the third day following tumor implantation, mice received injections of IL-2 (5 × 10³–5 × 10⁴ units) or diluent twice daily, either by i. p. or intratumoral injection, 5 days/week for 3 weeks. Intratumoral injection of 5 × 10⁴ units IL-2 significantly reduced tumor volume (P <0.05 versus control), increased median survival time (P = 0.0001), and resulted in a 23.5% cure rate (P = 0.008). There were no long-term survivors in the other treatment groups. Both tumor-infiltrating lymphocytes (TIL) and splenic lymphocytes isolated directly from IL-2-treated mice demonstrated enhanced cytolytic activity compared to diluent-treated controls. To determine whether non-T-cell-mediated antitumor responses were active in our model, intratumoral immunotherapy was evaluated in athymic Balb/cnu/nu mice. In order to decrease the recruitment of lymphocyte precursors, nude mice were splenectomized and received cyclophosphamide prior to tumor injection and IL-2 therapy. Intratumoral IL-2 immunotherapy also significantly decreased tumor volume in these immunodeficient mice (P <0.02), but did not lead to long-term survival. We conclude that both TIL and splenic lymphocytes are activated in vivo in response to intratumoral IL-2 immunotherapy, suggesting that intratumoral therapy with IL-2 activates both local and systemic antitumor responses.Supported by the Tobacco-Related Disease Research Program of the University of California, the Cancer Research Coordinating Committee, the Jonsson Cancer Center Foundation, and Veterans Administration Medical Research Funds     

The lantern of Aristotle: organization of its coelom and origin of its muscles (Echinodermata,Echinoida)

Summary Comparative ultrastructural analyses of the muscles that work the lantern of Aristotle support the opinion that the muscles in question are myoepithelially organized or derivatives of myoepithelia. They are part of the epithelium of the peripharyngeal cavity (=lantern coelom). The coelom epithelium may become multiplelayered in certain regions and is composed of (1) a layer of muscle cells that vary in number and size, (2) nerve cells and their processes that are interspersed between the muscle layer and (3) monociliated adluminal cells that build a continuous cell lining and completely cover the muscle layer. According to their complexity, the lantern muscles exhibit consecutive stages of myoepithelial variations and may finally simulate subepithelial musculature. The results of this study support the hypothesis of a histological development of subepithelial musculature from simple myoepithelia, although both epithelial and mesenchymal musculature may occur in the Echinodermata. Detailed knowledge of the organization of the lantern's coelom space was a prerequisite for the present study. In contrast to previous examinations the lantern coelom is not a continuous space, but is subdivided into several cavities that are partially completely separated from each other. On the one hand, this subdivision is probably caused by the sophisticated arrangement of the lantern's ossicles and on the other by the septa that give rise to muscles that fulfill different functions. lanter's ossicles and on the other by the septa that give