Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1985-1989  (19)
  • 1980-1984  (11)
  • 1970-1974  (7)
  • Cell & Developmental Biology  (34)
  • nitrogen  (3)
  • 1
    ISSN: 1573-1561
    Keywords: Heterotheca subaxillaris ; Asteraceae ; Pseudoplusia includens ; Lepidoptera ; Noctuidae ; volatile terpenes ; nitrogen ; herbivory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Nitrogen-limited plants ofHeterotheca subaxillaris accumulate greater quantities of leaf volatile terpenes than do nitrogen-rich plants. A series of feeding trials were performed to determine if such nitrate-limited plants are better defended against generalist-feeding insect herbivores. Soybean looper (Pseudoplusia includens) larvae were fed leaves fromH. subaxillaris rosettes grown under high and low nitrate supply regimes. Larval consumption, growth, and survival declined as the leaf volatile terpene content increased. Larval consumption and growth were enhanced by higher plant nitrate supply and with increasing leafage. The results suggest that the higher quantity of volatile terpenes in the leaves of nitrate-limited plants may better defend these leaves against generalist-feeding insects.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 1459-1467 
    ISSN: 1573-1561
    Keywords: Diplacus aurantiacus ; Scrophulariaceae ; Euphydryas chalcedona ; Lepidoptera ; Nymphalidae ; flavonoid ; herbivory ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Euphydryas chalcedona prediapause larvae were reared on fertilized and control shrubs of the host plant,Diplacus aurantiacus. Larval growth was enhanced by high leaf nitrogen content and inhibited by high leaf phenolic resin content. Larvae fed less on leaves near the branch tip which contained a higher leaf resin content. The results agree with prior laboratory investigation that the dietary content of nitrogen andD. aurantiacus leaf resin are major determinants ofE. chalcedona larval growth and suggest that the phenolic leaf resin ofDiplacus may both deter and inhibit leaf herbivores.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 1579-1588 
    ISSN: 1573-1561
    Keywords: Heterotheca subaxillaris ; Asteraceae ; monoterpene ; sesquiterpene ; nitrogen ; leaf age ; metabolism ; turnover ; chemical defense ; biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The concentration of leaf mono- and sesquiterpenes is greater in nitrate-limited than in nitrate-richHeterotheca subaxillaris plants and is highest in young leaves and declines with leaf age. To determine whether rates of volatile terpene synthesis and/or loss vary with nitrate availability and leaf age, incorporation of14C from photosynthetically fixed14CO2 and the subsequent loss of label was measured in plants grown under nitrate-limited and nitrate-rich conditions.14C incorporation into mono- and sesquiterpenes was greater in nitrate-limited than in nitrate-rich plants and was highest in young leaves and declined with leaf age. Incorporation continued for several days after exposure, while loss of label was slow until leaves were 4–6 weeks old. These results suggest that the higher leaf volatile terpene content observed under nitrate limitation apparently results from increased synthesis per leaf and accumulation of mono- and sesquiterpenes in immature leaves of nitratepoor plants. Furthermore, volatile terpene synthesis is highest in young leaves, declines with leaf age, and is very low in older leaves. Carbon used for synthesis of this pool may be derived from both current photosynthesis as well as carbon transported to young leaves from older leaves. These data are consistent with hypotheses that predict that greater levels of carbon-based chemical defenses occur in plants under nutrient limitation. The apparent low metabolic cost of maintenance (i.e., slow turnover) of the accumulated terpenoid pool would limit the energetic cost of volatile terpenes as a chemical defense.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 200 (1981), S. 67-81 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Buccopharyngeal epithelium covering gill arches and gill rakers of the fathead minnow was studied by light microscopic, scanning, and transmission electron microscopic techniques. Mature mucous cells in goblet pattern and nonmucus containing cells were in the apical one-third of the tissue. The latter cells contributed to a surface microridge system which overlapped apices of goblet cells. The bottom of the epithelium was comprised of a continuous row of darkly stained basal epithelial cells. In this region, two to three epithelial cells of similar staining characteristics were piled up forming apical columns which partially encircled nests of lightly stained cells. A basal lamina and thick basement lamella of about 20 plies of orthogonally arranged collagen supported the epithelium. Numerous taste buds were seen in gill arches and rakers. Taste bud cellular components included marginal cells, light receptor cells, dark receptor cells, and basal cells. These were identical in all taste buds. Taste bud surface morphology differed between gill arch and raker. Pores of the former were depressed, while those of the latter were raised. Thick microvilli of taste pores were apical extensions of light cells, while smaller, more numerous microvilli were projections from dark cells.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ovarian morphology and behavioral relationships were studied in a group of nine miniature pigs with a characteristically small litter size (∼5) and an average coefficient of inbreeding of 0.39. The first day of standing estrus was designated as day 0. Laparoscopy was used to evaluate and photograph ovarian activity on days 1, 5, 11, 17, and day 2 of the subsequent estrous cycle. Mean (±SEM) duration of estrus and the estrous cycle was 3.1±0.2 and 22.6±0.3 days, respectively. An average of 9.0±0.4 vesicular follicles developed/estrous period and 96% of the follicles showed morphologic evidence of ovulation resulting in a mean of 8.6±0.3 corpora lutea (CL) per animal. There was no significant correlation between the degree of inbreeding and number of vesicular follicles (r=0.27) or CL (r=0.28) developing/cycle within the experimental group. Mature preovulatory follicle and CL size ranged from 6-12 mm and 8-12 mm in diameter, respectively, and 22.5% of the newly formed CL contained distinct postovulatory stigmata. These data indicated that 1) temporal relationships of sexual behavior and gross ovarian morphology in the miniature pig were similar to descriptions previously reported for the standard pig, and 2) the reduced litter size characteristic to this particular strain is, at least in part, due to decreased number of vesicular follicles developing during the estrous cycle.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 213 (1985), S. 514-517 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A 10,000-dalton calcium-binding protein (10-kd CaBP) has been described in the placentae and yolk sacs of rats and mice. This protein is similar or identical to vitamin D-dependent intestinal CaBP and these proteins have been implicated in the molecular mechanisms of intestinal calcium absorption and transplacental calcium transport. Using an antiserum to the purified 10-kd rat intestinal CaBP, the localization of CaBP in the 16-17-day mouse yolk sac and placenta was studied immunocytochemically with peroxidase-antiperoxidase labelling and quantified by radial immunodifussion. A high concentration of immunolabelling was observed in the endodermal cells of the intraplacental yolk sac lining the sinuses of Duval. The columnar endodermal cells lining one side of the endodermal sinuses adjacent to fetal vessels contained most of the immunoreactive label. Quantitation by radial immunodiffusion demonstrated a 5.5-fold higher concentration of CaBP in the portion of the placenta containing most of the intraplacental yolk sac than in the maternal half of the placenta. This demonstration of a 10-kd CaBP within the intraplacental yolk sac suggests this protein functions to facilitate placental calcium transport and is the first study which directly supports the hypothesis of a functional role for the sinuses of Duval in calcium transport.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 221 (1988), S. 619-634 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The intrahepatic biliary system was studied in the rainbow trout (Salmo gairdneri), a teleost known to form liver neoplasms after exposure to various carcinogens. Normal adults (N = 25) were examined using light microscopic, enzyme histochemical, and transmission and scanning electron microscopic methods. In light micrographs, longitudinal arrays of hepatocytes appeared as double rows incompletely divided by elongated darkly stained cells. Electron micrographs showed tubules of five to nine pyramidally shaped hepatocytes with their apices directed toward a central biliary passageway and their bases directed toward sinusoids. Sequentially, beginning with hepatocytes, biliary passageways included canaliculi, preductules, ductules, and ducts. Canaliculi were short and joined transitional passageways (preductules) formed by junctional complexes between plasma membranes of hepatocytes and small, electron-dense cells with a high nuclear to cytoplasmic ratio. Ductules, completely lined by biliary epithelial cells, occupied central regions of hepatic tubules. Relatively elongated, ductular cells were intimately associated with surrounding hepatocytes, separated from them by only a thin extracellular space devoid of a basal lamina. Epithelium of bile ducts included cuboidal through mucus-laden columnar cells, surrounded by basal lamina and, in larger ducts, by fibroblasts, smooth muscle cells, and a capillary plexus. Bile ducts and hepatic arterioles, but not venules, were distributed together. The ultrastructure of biliary epithelium, periductular, and periductal cells is presented.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 212 (1985), S. 327-335 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Glycoprotein components of epidermal mucous cells in control (pH 6.8) and acid-stressed (pH 5.8, 4.8, 4.0) brown bullhead catfish were studied by histochemical and autoradiographic methods. Following exposure to acid, increased numbers of epidermal mucous cells were noted in all tissue sites studied, particularry dorsal and ventral skin. Mucous cells of control fish and acid-stressed (pH 5.8) fish contained a mixture of neutral and acidic mucosubsf ances, the latter including both sialomucins and sulfomucins, with sialomucins predominating. An apparent shift toward increased sulfomucin production was observed in skin from fish exposed to pH 4.8 and 4.0. In addition, autoradiographic studies using 35S showed increased labeling of mucous cells in acid-exposed (pH 4.0) epidermis, offering further support for a shift toward sulfomucin production in acid-stressed fish. Absence of appreciable sulfomucin production in younger fish (〈1 year old) suggested that this shift may be partly age-dependent. The functional significance of increased sulfomucin production in acid-stressed epidermal mucous cells is uncertain but may be related to maintenance of ionic equilibrium.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The calcium-binding protein (CaBP) calbindin has been implicated in the molecular mechanism of placental calcium transfer. Previous light microscopic studies have identified CaBP in visceral (but not parietal) endodermal cells of the yolk sac with the most intense immunocytochemical signal observed in the intraplacental yolk sac. In the present studies, electron microscopy was used to study the localization of CaBP in placenta.Placentas of 17-day pregnant mice were fixed by perfusion in 0.5% gluteraldehyde, embedded in low-temperature Lowicryl K4M, and examined in thin section for specific labeling with a polyclonal antiserum. Antibody to CaBP was localized by using protein A-gold particles which were quantified for subcellular compartmentation by using a Videoplan computer system. A high signal for CaBP was found in the visceral endodermal cells of the intraplacental yolk sac. In these cells, gold particles indicating the location of CaBP were observed over (1) the cytoplasmic matrix where the average number of gold particles per μm2 was 33; (2) the microvilli (17/μm2); (3) the mitochondria (17/μm2); and (4) the nucleus (43/μm2). Sections from antigen-absorbed controls, by contrast, showed few gold particles: cytosol, 2/μm2; microvilli, 5/μm2; mitochondria, 5/μm2; and nucleus, 4/μm2. Electron-lucent profiles of the Golgi and endoplasmic reticulum contained no particles in the controls and a low particle count (4/μm2) in the stained sections. Parietal endodermal cells of the intraplacental yolk sac showed a relatively low signal for CaBP compared with the visceral endodermal cells (5 particles/μm2 vs. 39). Only low numbers of gold particles were observed in trophoblasts (6/μm2), lymphocytes (5/μm2), and erythrocytes (5/μm2). These findings indicate that 9 kd CaBP is located predominantly in cytoplasmic matrix, nucleus, and mitochondria within the visceral endodermal cells of the intraplacental yolk sac.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The third ventricular walls and floor of male and female mink (Mustela vison) were analyzed with comparative light microscopy, transmission and scanning electron microscopy. Distinct regional fine structural variations were noted in the appearance of the dorsal, middle third and lower portions of the ventricular wall and floor. These variations were characterized by an abrupt decrease in the density of ciliated ependymal surfaces in the middle one-third of the ventricular wall. The ventral walls and floor of the lateral and infundibular recesses displayed smoother contours with numerous bleb-like protrusions and blunt villiform processes. Occasionally multipolar neuron-like cells were observed to lie upon the floor of the infundibular recess. Speculation is raised relative to the differing functional capacities of these various ventricular areas.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...