Examination Of Whole Mounts Research Articles

Heterocapsa busanensis sp. nov. (Peridiniales, Dinophyceae): A new marine thecate dinoflagellate from Korean coastal waters

During daily monitoring in Yongho Bay off Busan, Korea in 2019, an isolate of the dinoflagellate genus Heterocapsa was established in clonal culture. Light and electron microscopic examination revealed that the isolate was ellipsoid in shape, exhibiting a thecal plate arrangement (Po, cp, X, 5′, 3a, 7″, 6c, 5s, 5‴, 2ʹʹʹʹ) consistent with most other Heterocapsa species. A large, elongated nucleus was positioned on the left side of the cell, a single reticulate chloroplast was located peripherally, and a single, starch-sheathed, spherical pyrenoid was present in the episome or near the cingulum. Morphologically, the isolate most closely resembles H. circularisquama and H. illdefina. Transmission electron microscopic examination of whole mounts revealed that the isolate had two body scale types, one of which was a complex, three-dimensional, fine structure distinct from other Heterocapsa species, whereas the other simpler type was structurally similar to the scales of H. horiguchii. Molecular phylogeny based on rRNA sequences revealed that the isolate was distantly related to morphologically similar species, but formed a sister lineage to H. horiguchii, a species characterized by a similar body scale morphology. Based on morphological, ultrastructural, and molecular data, we proposed it as a new species, Heterocapsa busanensis sp. nov.

MP42-19 A MULTIPARAMETRIC MAGNETIC RESONANCE IMAGING (MPMRI) PILOT STUDY OF PROSTATIC PERI-URETHRAL FIBROSIS (PUF), A POSSIBLE ALTERNATIVE SOURCE OF LUTS

You have accessJournal of UrologyImaging/Radiology: Uroradiology II (MP42)1 Apr 2020MP42-19 A MULTIPARAMETRIC MAGNETIC RESONANCE IMAGING (MPMRI) PILOT STUDY OF PROSTATIC PERI-URETHRAL FIBROSIS (PUF), A POSSIBLE ALTERNATIVE SOURCE OF LUTS Alexander Kenigsberg*, Ryan Mauck, Alberto Diaz de Leon, Claus Roehrborn, Douglas Strand, and Daniel Costa Alexander Kenigsberg*Alexander Kenigsberg* More articles by this author , Ryan MauckRyan Mauck More articles by this author , Alberto Diaz de LeonAlberto Diaz de Leon More articles by this author , Claus RoehrbornClaus Roehrborn More articles by this author , Douglas StrandDouglas Strand More articles by this author , and Daniel CostaDaniel Costa More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000891.019AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We recently described a new fibroblast subtype around the prostatic urethra. Examination of whole mounts from patients undergoing simple prostatectomy revealed that about 20% had PUF. Single cell RNA sequencing and immunostaining revealed that the origin of this fibrosis is the peri-urethral fibroblast, the only collagen-producing prostatic cell type. An emerging hypothesis is that PUF is involved in the pathogenesis of LUTS, particularly in men with smaller glands, but clinical tools are needed. The purpose of this study was to evaluate for the presence of PUF on mpMRI in men for whom whole mount data is not available. METHODS: Men who underwent 3T endorectal coil mpMRI between 2016-2018 for elevated PSA, MRI estimated prostate volume<60cc, and with known AUA symptom score (AUASS) were included. Patients with PIRADS >=2 lesions in the transition zone and prior bladder outlet surgery were excluded. Images were retrospectively interpreted by a radiologist dedicated to prostate MRI, who was aware of suspected prostate cancer (PCa) and blinded to other clinicopathologic findings. High resolution, fast spin-echo axial T2-weighted images part of the mpMRI were assessed for the presence of a PUF tissue (hypointense soft tissue encircling the intraprostatic urethra), its circumferential extent in degrees (0, 25, 50, 75, 100) and the maximum thickness (Figure 1). Univariate analysis and Pearson correlation were used to evaluate relationship between AUASS and PUF. RESULTS: 72 patients met inclusion criteria. PUF was identified in 20/72 (28%) with a mean circumferential extent of 47 degrees and thickness of 2.8 mm. The median AUASS was 7 (mild) and only 2/72 (2.8%) had an AUASS≥20 (severe). There was no difference in AUASS between those with PUF and without (7.8 vs 6.6, p=.48). Circumferential extent, PUF thickness, PSA, and prostate size did not correlate with AUASS. Only age correlated with AUASS (r=.3, p<.01). PCa on biopsy did not predict LUTS (p=.47). CONCLUSIONS: PUF is identified on mpMRI. The correlation of PUF and LUTS remains investigational, as this cohort largely had mild symptoms. Fibrotic processes remain a potential explanation for LUTS in men with smaller glands. Further investigation is necessary to define this relationship and identify these patients. Source of Funding: None © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e611-e611 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Alexander Kenigsberg* More articles by this author Ryan Mauck More articles by this author Alberto Diaz de Leon More articles by this author Claus Roehrborn More articles by this author Douglas Strand More articles by this author Daniel Costa More articles by this author Expand All Advertisement PDF downloadLoading ...

Emendation ofCarpobothrium(“Tetraphyllidea”) from Bamboosharks (Orectolobiformes: Hemiscyliidae) with Redescription ofCarpobothrium chiloscylliiand Description of a New Species from Borneo

ABSTRACT: Collection of new material from the bamboosharks Chiloscyllium indicum (Gmelin, 1789) and Chiloscyllium hasseltii Bleeker, 1852, from Indonesian and Malaysian Borneo prompted reevalutation of the identity and host associations of the cestode genus Carpobothrium Shipley and Hornell, 1906. Light microscopical examination of whole mounts, histological sections, and egg preparations, in combination with scanning electron microscopy of scoleces, led to redescription of the type species Carpobothrium chiloscyllii Shipley and Hornell, 1906, from Ch. indicum, as well as description of a new species from Ch. hasseltii. The proglottid anatomy of C. chiloscyllii is described for the first time. The genus was confirmed to exhibit pouch-like bothridia with relatively small anterior and posterior flaps that have a tendency to retract into the bothridial pouches, testes that are entirely pre‐poral, a uterus that extends only to the cirrus sac, and a vas deferens that coils posterior to the cirrus sac. Althoug...

Dengue virus-induced autophagosomes and changes in endomembrane ultrastructure imaged by electron tomography and whole-mount grid-cell culture techniques.

The biogenesis events and formation of dengue virus (DENV) in the infected host cells remain incompletely understood. In the present study, we examined the ultrastructural changes associated with DENV-2 replication in three susceptible host cells, C6/36, Vero and SK Hep1, a cell line of human endothelial origin, using transmission electron microscopy, whole-mount grid-cell culture techniques and electron tomography (ET). The prominent feature in C6/36 cells was the formation of large perinuclear vacuoles with mature DENV particles, and on-grid whole-mount examination of the infected Vero cells showed different forms of DENV core structures associated with cellular membranes within 48 h after infection. Distinct multivesicular structures and prominent autophagic vesicles were seen in the infected SK Hep1 cells when compared with the other two cell lines. ET showed the three-dimensional organization of these vesicles as a continuous system. This is the first report of ET-based analysis of DENV-2 replication in a human endothelial cell line. These results further emphasizes the strong role played by intracellular host membranes–virus interactions in the biogenesis of DENV and strongly argues for the possibility of targeting compounds to block such structure formation as key anti-dengue agents.

Urothelial carcinoma in the prostatic urethra and prostate: current controversies

We reviewed the literature on urothelial carcinoma in the prostatic urethra and prostate. We concluded that the incidence of urothelial carcinoma in the prostatic urethra and prostate is probably underestimated. This fact warrants thorough follow-up of patients with high-risk bladder cancers and also whole-mount examination of the prostate after cystectomy to recognize the true incidence and extent of such tumor involvement. Resectoscope loop biopsy is the method of choice to detect urothelial carcinoma in the prostatic urethra/prostate and such biopsies should include the area around the verumontanum to ensure optimal sensitivity. Carcinoma in situ in the prostatic urethra should be treated with intravesical Bacillus Calmette–Guérin and a transurethral resection of the prostate prior to that treatment might increase the contact of Bacillus Calmette–Guérin with the prostatic urethra, improve staging and in itself treat the prostatic involvement. Conservative treatment of carcinoma in situ in the prostatic ducts is an option, although radical surgery is probably best for treating extensive intraductal involvement, since data on the former strategy are inconclusive. Patients with stromal invasion should undergo radical surgery. It is necessary to take the route of prostatic involvement into account when estimating prognosis in each individual patient, since contiguous growth into the prostate is associated with worse prognosis. Prospective studies using a whole-mount technique to investigate the prostate are needed to clarify both the role of different routes of prostate invasion and the prognostic significance of different degrees of prostate invasion. At cystectomy, when urothelial carcinoma is present in the prostatic urethra and/or prostate, it is necessary to balance the risk of urethral recurrence and decreased sexual function against opinion and expectations expressed by the patient during preoperative counseling regarding urinary diversion and primary urethrectomy.

A simple device to rapidly prepare whole mounts of murine intestine

Many mouse models of neoplasia and pre-neoplasia require the examination of whole mounts of the gastrointestinal tract. A simple device has been produced to facilitate the rapid preparation of mouse intestines for subsequent quantification of tumours and pre-neoplastic lesions such as aberrant crypt foci. The device greatly speeds up the production of whole mounts and also provides far more consistent and better-quality preparations.

Nanoflagellates of the central California waters: taxonomy, biogeography and abundance of primitive, green flagellates (Pedinophyceae, Prasinophyceae)

Examination of whole mounts of cells prepared from samples collected off central California, September 1989, has led to the identification of 14 taxa of primitive green nanoflagellates from the Pedinophyceae (1 species) and the Prasinophyceae (13 species). Three of the prasinophyte taxa are new to science. The finding of these new taxa, provisionally identified as Prasinophyte “Point Sur” sp. 1, 2, 3, is important because it emphasizes the persistent, overall lack of knowledge of prasinophyte biodiversity, and also because these forms combine prasinophycean features in a unique way that ultimately may question the currently accepted taxonomic system. The abundance estimates suggest that prasinophytes are most numerous in coastal waters and are relatively absent from oceanic regimes.

Renicola williamsi n. sp. (Trematoda: Digenea: Renicolidae) from the South Polar Skua, Catharacta maccormiki

Renicola williamsi n. sp., is described from specimens collected from the South Polar skua Catharacta maccormiki. R. williamsi differs from other renicolids by its short esophagus, linear and mediolateral arrangement of vitelline follicles, linear extent of intestinal caeca, gonadal shape, caecal width, reduced sucker ratio, and disposition of the uterus. Fifteen specimens were compared with existing morphological descriptions of adult Renicola and Nephromonorcha. Renicolid trematodes are parasites in the kidneys of birds (Yamaguti, 1971). Dollfus (1946) revised the Renicolidae (Dollfus, 1939), listing nine flukes from the renal organs of birds together with a taxonomic key for species identification. Since 1946, various authors have attempted to devise new taxonomic keys for Renicolidae (LaRue, 1957; Odening, 1962; Riley & Owen, 1972; Sudarikov & Sten'ko, 1984; Wright, 1954, 1956, 1957). Of the 56 known species of Renicolidae, two were described on the basis of cercariae only (Martin, 1971; Martin & Gregory, 1951). We agree with Sudarikov & Sten'ko (1984) in considering Renicola (Cohn, 1904) and Nephromonorcha (Leonov, 1960) to be the only valid genera. Their mutual exclusion is based on testicular fusion in the latter. Prior to the present study, renicolid trematodes never have been recovered from birds within the Antarctic Circle. Sergeeva (1971) reported Renicola lari (Timon-David, 1933) from the parasitic jaeger, Stercorarius parasiticus (L.) in north-central Siberia. This host is a vagrant of the sub-Antarctic (Watson, 1975). Several species of captive penguins known to inhabit Antarctic or sub-Antarctic regions, were reported to harbor Renicola sloanei Wright, 1954 (see Campbell & Sloan, 1943; Wright, 1956). A total of 37 South Polar Skua, Catharacta maccormiki (Saunders), were collected near McMurdo and Hallett stations, Antarctica. Post-mortem examinations resulted in the recognition of three birds infected with kidney flukes. After preliminary microscopic examination of whole mounts, the trematodes were determined to be renicolids, based on linear distribution of follicular 1 This investigation was supported in part by NSF Grant DPP76-239-79, to the Smithsonian Institution, B. J. Landrum, Principal Investigator, and by grants from the Biology Department and Graduate School, University of North Dakota. Publication costs, in part, are being met by a grant from the Spencer-Tolles Fund of the American Microscopical Society. 2 Present address: Experimental Pathology Program, Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, South Carolina

Cytokines up-regulate Ia expression in organotypic cultures of central nervous system tissue.

Myelinated cultures of embryonic SJL/J mouse spinal cord tissue have been tested for their ability to express class II major histocompatibility complex (MHC) (Ia) molecules in the presence of two recombinant cytokines, mouse interferon-gamma (IFN-gamma) and human tumor necrosis factor-alpha (TNF-alpha). Both cytokines up-regulated class II MHC in a dose-dependent manner and interacted synergistically to increase Ia when applied together. The principal cell type involved were glial fibrillary acidic protein-positive astrocytes along the surface of the cultures. Immunocytochemistry in combination with light microscope examination of whole mounts and epoxy sections as well as electron microscopy, were used to assess the phenomena. These findings add further weight to previous observations on astrocytes being capable of serving as antigen-presenting cells within the central nervous system.

Penetration and infection of western larch seedlings by Botrytis cinerea

The fungus Botrytis cinerea Persoon (ex Fries) is an important pathogen of container-grown conifer seedlings. The examination of whole mounts and serial sections of diseased needles of western larch (Larix occidentalis Nuttall) seedlings with a light microscope confirmed that the development of fungal infection structures conforms to that observed in nonconiferous hosts. Both stomatal and cuticular penetrations were evident. Infection hyphae displayed occasional taxis toward stomata on senescent needles but not on healthy needles. The treatment of seedlings with fungicides at levels corresponding to 1 and 10% normal application rates induced no consistent changes in fungal structures.

Nanoplanktonic coccolithophorids (Prymnesiophyceae, Haptophyceae) from the Weddell Sea, Antarctica

The examination of whole mounts prepared for transmission electron microscopy has resulted in the finding of thirteen taxa of nanoplanktonic coccolithophorids from the Weddell Sea, Antarctica. The material was collected as part of the AMERIEZ programme, March 1986. Cold‐water adapted nanoplanktonic coccolithophorids have previously been shown to constitute a recurrent plankton element at subarctic and arctic localities. Three of the Weddell Sea species, Wigwamma annulifera, W. arctica, and Papposphaera sagittifera, are conspecific with northern hemisphere material, while two species, Calciarcus alaskensis and Turrisphaera arctica, are possibly identical with previously described arctidsubarctic material. Six taxa new to science have been described from the Weddell Sea, Wigwamma antarctica, W. triradiata, Trigonaspis melvillea, Pappomonas weddellensis, Papposphaera obpyramidalis, and P. simplicissima. The cooccurrence of identical forms at the two poles, and the fact that the species described are allocated to “arctic” genera, indicate a geologically relatively recent exchange of biological material between the poles.

Occurrence of Adult and Developmental Stages of Proctoeces maculatus (Trematoda: Digenea) in the Gastropod Crepidula convexa

Metacercaria and unencysted juvenile and adult Protoeces maculatus are reported in the gastropod Crepidula convexa. The metacercaria and metacercarial cyst are described. Staining of the encysted worms and the cyst wall with toluidine blue and Alcian blue indicates that the metacercaria has cystogenous glands. The cyst appears to be of parasite origin, and there is no marked host response. Sexually mature worms found in C. convexa are true adults and not metacercaria. Ovigerous parasites migrate to the nephridium of the snail where eggs are deposited and may leave the host via the renal pore. The incidence of infection in snails collected at Breezy Point, New York was 7-75% during the year and was always higher in females. P. maculatus can complete its life cycle without a vertebrate host using C. convexa as an alternative definitive host. In 1981, many specimens of Crepidula convexa Say collected at Breezy Point, New York were found to be infected with a digenetic trematode. Based upon examination of whole mounts of juvenile and adult worms, the parasite was identified as Proctoeces maculatus (Looss, 1901) Odhner, 1911. The present study was initiated to investigate the host-parasite relationship between C. convexa and P. maculatus and to study the developmental stages of the worm in this snail. Proctoeces spp. have been reported from the hindgut of several families of bottom-feeding fishes, primarily Sparidae and Labridae (see Freeman & Llewellyn, 1958; Prevot, 1965; Wardle, 1980). The asexual and larval stages of P. maculatus have been found in several bivalves including the mussels Mytilus edulis, Brachiodontes recurvus, and Mytilus galloprovincialis (Hopkins, 1954; Prevot, 1965; Stunkard & Uzmann, 1959). Unencysted, metacercariae of P. maculatus have been described from the bivalves Scrobicularia plana, Mytilus edulis, and Crassostrea virginica, as well as from the gastropod Rissoa splendida (see Freeman & Llewellyn, 1958; Machkevesky & Parukhin, 1980; Uzmann, 1953; Winstead & Couch, 1981). Wardle (1980) reported finding unencysted, non-progenetic metacercariae of P. maculatus in the mussels Ischadium recurvum (=B. recurvis) and Mytilopsis leucopheata (=Congeria leucopheata). The term progenetic is applied to sexually mature, ovigerous digenetic trematodes occurring in invertebrates. The worms are considered 1 We thank Dr. David Franz for his critical reading of the manuscript and his many helpful

Latent infection of winter oilseed rape by Leptosphaeria maculans

Plants of oilseed rape, cultivars Primer and Jet Neuf, were grown in a glasshouse and inoculated at G.S. 2.4–2.7 with pycnidiospores or ascospores of Leptosphaeria maculans. The plants were kept for a further 2–4 weeks at 14°C and then transferred, together with uninoculated plants, to a polythene tunnel in winter. The majority of stems of inoculated plants did not have macroscopic symptoms of L. maculans infection 6 weeks after inoculation. Examination of whole mounts of peripheral tissue and transverse sections of fixed and embedded portions of these stems revealed intercellular septate fungal hyphae, often deep in non‐necrotic cortical tissue, in symptomless inoculated plants but not in uninoculated plants. L. maculans was recovered following surface sterilization of adjacent portions of the same stems. When symptomless inoculated plants were transferred to a glasshouse at 18–20°C, cankers soon developed. The significance of these latent mycelial infections to canker development in the field is discussed.

Embryonic chick retinal ganglion cells identified "in vitro". Their survival is dependent on a factor from the optic tectum.

When HRP is injected into the optic tecta of embryonic or newly hatched chicks, the ganglion cells in the contralateral retina can be successfully dissociated into culture and identified at any time by appropriate histochemical staining. Histological examination of whole mounts of retinae both ipsilateral and contralateral to an injection site indicated that no HRP diffused out of an injected tectum, and that the only reaction product that could be visualized was restricted to the ganglion cell layer of the contralateral eye. Because retinal ganglion cells are the only retinal neurons to project to the optic tectum, the intraxonal retrograde transport of HRP to these cells allows their unequivocal identification from amongst the heterogeneous population of retinal neurons present after dispersal into single cells in monolayer culture. The presence of HRP in the cell bodies did not appear to impair their ability to survive, grow or express neurites. Counts of labeled cells from progressively aged birds confirmed that the peak number of generated ganglion cells occurs on embryonic day 10,and that is a 40% decline in the number these neurons over the following 3 days. However, when labelled ganglion cells from 10 day embryos were grown in culture with optic tectum, all the ganglion cells survived over the following 4 days, including those destined to die in vivo. This trophic effect cannot be induced by cerebellum, but is partly induced by media first conditioned over tectal cells. The trophic effect exerted by optic tectum appears therefore to be specific and chemically mediated. We suggest that the death of retinal ganglion cells in vivo may be a consequence of the inability of some cells to establish adequate supplies of a growth factor from the optic tectum.

Penetration of cucumber leaves by Colletotrichum lagenarium is reduced in plants systemically protected by previous infection with the pathogen

Microscopic examination of whole mounts and sectioned leaf tissue indicated that penetration of cucumber leaves by Colletotrichum lagenarium was reduced in both resistant and susceptible cultivars when the plant was systematically protected by previous infection with the pathogen. Differences were not observed, however, in the number of appressoria produced on protected or unprotected leaves. The degree of protection was reduced by puncturing or abrading the leaf surface of the susceptible cultivars prior to inoculation, and protection was lost by removing a portion of the leaf's epidermal tissue and inoculating the exposed sites with the fungus. Protection was not effective at leaf sites with the epidermis removed even when low concentrations of inoculum were used. Removal of epidermis did not reduce resistance or protection of a resistant cultivar. The resistance of the cultivars Calypso, Addis and Liberty to anthracnose was not due to a reduction in the formation of appressoria or penetration, but was associated with rapid necrotization of penetrated cells. Infectious C. lagenarium was isolated from lesion-free inoculated areas on leaves of systematically-protected plants up to one week after inoculation.

Notes on the ultrastructure of the genus Paraphysomonas (Chrysophyceae) with special reference to P. bandaiensisTakahashi

Paraphysomonas bandaiensisTakahashi is recorded for the first time outside Japan and the shape of its body scales is described from sectioned material. The scales have a circular baseplate and a central spine and are more or less umbrella-shaped, the baseplate being curved and not flat as might have been surmised from examination of whole mounts only. The spine is hollow and represents an extension of a conical protrusion from the concave face of the baseplate. The scales appear to be formed in peripheral vesicles each of which is characteristically associated with a rough ER cisterna. Stalked cells of P. imperforataLucas, P. bandaiensis and P. foraminiferaLucas are described, for the first time in the latter two species.

Two New Species of Acanthobothrium Van Beneden 1849 (Cestoidea: Tetraphyllidea) from Freshwater Stingrays in South America

Two new species of Acanthobothrium are reported from freshwater stingrays in northern South America. Acanthobothrium quinonesi sp. n. is described from Potamotrygon magdalenae Dumeril collected from the Magdalena River in northern Colombia and A. amazonensis sp. n. from P. circularis Garman collected in the Itacuai River of northwestern Brazil. Acanthobothrium quinonesi differs from A. amazonensis by having a smaller and anteriorly-curved cirrus sac, 43-60 rather than 50-72 testes, and bothridial hooks 100--142 ,urn long rather than 145-184 ,urn long. Characters used in the taxonomy of Acanthobothrium species are listed to show that the new species resemble each other and A. terezae, also from a South American freshwater stingray, more than they do any other members of the genus. Species of Acanthobothrium van Beneden 1849 parasitize a variety of marine and estuarine elasmobranchs (Goldstein, 1967; Williams, 1969) . Collections from the freshwater stingrays Potamotrygon magdalenae Dumeril in the Magdalena River of Colombia and from P. circularis Garman in th e Itacuai River of Brazil, contained specimens of two new species of Acanthobothrium which resemble each other more than they do any other known species. Worms were removed from host spiral valves, examined alive and fixed with warm AFA, or fixed in situ with 10% formalin; all were stored in 70 % ethanol. Study included examination of whole mounts stained with Mayer's hematoxylin and mounted in Canada balsam as well as study of serial cross sections cut at 8 p.m and stained with hematoxylin-eosin. Measurements are in urn unless otherwise stated with number of measurements (N) and mean values (x) indicated for certain characteristics. Figures were drawn with the aid of a drawing tube. Acanthobothr;um qu;nones; sp. n.

An ultrastructural survey of the chrysophycean genusParaphysomonasunder natural conditions

Electron microscopical examination of whole mounts, prepared from freshly collected seawater samples from the Isefjord area (Denmark), has led to the enumeration of seven species belonging to the chrysophycean genus Paraphysomonas. One of these is P. sideriophora sp. nov., characterised by its single type of scale, each resembling a flat-iron. Three of the species have previously been recorded from Denmark. Most of the type descriptions of Paraphysomonas species refer to accidentally cultured material. When the same species are observed under natural conditions, as in the present investigation, the variation in scale size and morphology is seen to be considerably wider than reported in the type descriptions. This applies in particular to P. foraminifera Lucas and P. imperforata Lucas. The discrepancies between the type descriptions and the present material is probably a reflection of the fact that cultured material consists of one or a few clones only (sexual reproduction is unknown), whereas the immediat...

Electron microscope observations of diatoms

1. Three-dimensional carbon replicas can be used to study frustular morphology with greater accuracy than either regular carbon replicas or nonreplicated frustules. Because of their resemblance to thru-focus drawings, carbon replicas are well-suited for taxonomic work, much more so than either light or electron micrographs of frustules. 2. Stephanodiscus hantzschiiGrun. has short spines paired with some of the long curved radial spines projecting from the valve margin. 3. Azure B staining of freshly collected diatoms may reveal the presence of tiny epiphytic bacteria on either the frustule or on extracellular polysaccharide structures which can later be detected by electron microscope examination of whole mounts. These epiphytic bacteria may derive part of their nutritional support by local digestion of diatom extracellular polysaccharides, while the bacteria in turn may provide organic nutrients required by their diatom host. 4. The variety of techniques now available enable one to conveniently use the electron microscope to answer most questions concerninig diatom structure.

Effect of Relaxin on Mammary Gland Growth in Female Mice.

SummaryIntact, ovariectomized, and ovariectomized-hysterectomized mice were treated with estrogen, estrogen and relaxin, and relaxin alone for periods of 10 days. It was shown that estrogen and higher levels of relaxin synergize in the promotion of lobule-alveolar growth as indicated by total DNA of the glands and by histological examination of whole mounts. Estrogen or relaxin alone did not stimulate such growth. Mean total DNA at optimal levels of relaxin was equal to that observed in mice pregnant 6 days. In the operated groups, reduced total DNA may be due to gland involution of 12 days.