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PubMed2005

Spread of Musca domestica (Diptera: muscidae), from two caged layer facilities to neighboring residences in rural Ohio.

Complaints of excessive numbers of flies were reported by citizens living in a rural area surrounding a large (>2 million laying hens) egg-layer facility in northwestern Ohio. Sticky cylinder traps and hanging fly strips were used at outdoor and indoor locations, respectively, at known distances from the layer farm and from control sites to determine the most likely source of the flies and to determine the severity of the problem compared with fly populations in nearby rural settings. House flies, Musca domestica (L.), were the predominant flies captured on fly traps located within 6.4 km of the poultry operations. There was a significantly greater number of M. domestica trapped in the study area surrounding the layer facility than in the control areas. The quantity of house flies captured decreased with increased distance from the layer farm. Two years into the study, a second egg-layer facility opened in an area that was originally a control site. With regard to this second farm, after 4 yr of study, there was a significant difference shown between the population of house flies during the 2-yr control phase and the 2-yr period when the egg-layer facility was operational. This study documented that large egg layer facilities can significantly increase the house fly population in the surrounding community up to 6.4 km from the source of the flies and may result in a severe nuisance up to 3.2 km away.

Animal Husbandry↗
PubMed1991

Contractile and non-contractile proteins and nucleic acids in the stomach, whole jejunum and seromuscular layers of the duodenum, jejunum, ileum and large intestine in response to chronic ethanol feeding.

Rats were fed a nutritionally adequate liquid diet containing 35% of the total calories as ethanol (treated), or identical amounts of the same diet in which ethanol was replaced with isocaloric glucose (controls). At 6 weeks, rats were killed and the stomach (cardiac region), duodenum, jejunum, ileum and the large intestine (combined colon and rectum) were dissected. Seromuscular layers were prepared from the duodenum, jejunum, ileum and the large intestine. After 6 weeks of chronic ethanol feeding the wet weights of the stomach and whole jejunum were reduced by 31%. The wet weights of the duodenum, jejunum and distal ileum seromuscular layers were reduced by 19-25%. The wet weight of the large intestine seromuscular layer was unaltered. The total amounts of contractile and non-contractile protein in the small intestinal seromuscular layers were reduced by 16-52%. In jejunal serosa, the RNA contents were reduced by 29%, but total RNA contents in the serosa of the ileum and duodenum were not significantly altered. Total DNA content was reduced in jejunal and ileal serosal layers by 22 and 33%, respectively, but remained unchanged in duodenal serosa. In the stomach, total contractile and non-contractile protein was reduced by 26-52% and similarly total RNA and DNA were also decreased by 47 and 34%, respectively. Chronic ethanol feeding had no apparent effect on either contractile or non-contractile total protein, total RNA or DNA contents in colonic and rectal serosa. In the combined mucosal and seromuscular layers of the jejunum, much greater effects due to ethanol feeding were observed when compared with the jejunal seromuscular layer alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcoholism↗
PubMed2000

Electron microscopy analysis of the boundary layer structure of SrTiO3 semiconducting ceramic

In a boundary layer (BL) semiconducting SrTiO3-based ceramic condenser, the BL structure has been investigated using high-resolution field-emission scanning electron microscopy (FE-SEM) and field-emission (scanning) transmission electron microscopy (FE-(S)TEM). In an initial TEM observation, a double layered structure was observed at the grain boundary region. It consisted of a grain boundary (second phase) and a pair of the metal diffusion layers of up to several nanometres in width across the grain boundary where the change of the crystal lattice distance was undetected by the high-resolution TEM image. A facet structure was often observed on the grain boundaries. It was particularly formed on (020) plane of the grain crystal. High resolution SEM showed a jagged striped structure on the surface of the bulk material and on the inside grain as revealed by fracture. Using the similarity in shape and size, it can be identified to correspond to the facet boundary structure. Its formation mechanism can be explained as that during the reoxidization process when the oxide flux of the mixture of Bi2O3, PbO and CuO, painted on the bulk material, surfaces migrates into the ceramic along the grain boundary. The oxide corrodes the grain surfaces including the bulk surfaces. This corrosion particularly occurs on (020) plane of the grain so that the facet structure is produced. In this paper, by using the atomic scale high angle annular dark field STEM, it has been determined that Bi atoms preferentially replace Sr atoms on (020) in the diffusion layers. The atom position displacement was also detected at the grain surfaces and this altered atomic assignment can be determined as an origin of production of Sr2Bi4Ti5O18 at the grain boundary. Also, it was observed that the layer width of the metal diffusion layers was often different between the both grains and changed locally so that the ribbon of the diffusion layers meandered around the straight grain boundary. Its possible mechanism is also proposed.

Journal Article↗
PubMed2001

Nutritive and economic values of high oil corn in layer diet.

Two layer feeding trials were conducted to demonstrate the nutritive and economic values of recently developed high oil corn (HOC) in Korea. A corn-soybean meal-based commercial layer diet was chosen as the control diet. The yellow dent corn in the control diet was replaced with HOC to give an isocaloric diet, or replaced with HOC on a 1:1 basis to give a high energy diet. In Trial 1, 510 23-wk-old ISA Brown layers were allotted to three dietary treatments with five replicates per treatment. In Trial 2, 600 38-wk-old Hy-Line Brown layers were allotted to three dietary treatments, again with five replicates per treatment. Both trials were conducted for 15 wk. To measure the ME values of typical corn and HOC, two metabolism trials were performed with layers and adult roosters. The HOC used in this trial contained approximately 94% higher crude fat (6.60% as-fed basis) compared with typical corns. The gross energy, AMEn, and TME values of HOC, are 5.7 to 7.7% higher than those of typical corns, indicating that the energy use of each corn were similar. Oil from the HOC contains 6.5 to 8.3% more oleic acid and 6 to 7% less linoleic acid than oil from typical corns. HOC feeding, on an isocaloric basis or on 1:1 replacement with typical corn, did not exert any effect on various laying performances, including the physical quality of egg. This result reflects the quality of the commercial diet chosen as the control diet, which was already fairly good, such that the performance was already maximal. The polyunsaturated fatty acid content in yolk from hens fed HOC was higher than that from hens fed typical corns, reflecting higher linoleic acid content in the HOC. HOC feeding decreased the saturated fatty acid content in the yolk, due primarily to decreased palmitic acid. If used alone replacing typical corn completely in a layer diet, the acceptance price of HOC was estimated to be 154 won/kg when the price of typical corn was 131 won/kg (118:100). When both corns were allowed to be used, the acceptance price of HOC increased to 184 won/kg (140:100), indicating that a lot cheaper layer diet can be formulated when both HOC and typical corn are used in laying hen diet formulation.

Animal Feed↗
PubMed2006

Effect of various combinations of alfalfa and standard layer diet on susceptibility of laying hens to Salmonella enteritidis during forced molt.

Feed deprivation is commonly used by the poultry industry to induce molting and stimulate multiple egg-laying cycles. However, feed deprivation has been observed experimentally to increase susceptibility of poultry to Salmonella infections. Previous studies indicated that alfalfa was efficacious in reducing Salmonella; the present investigation was designed to evaluate the efficacy of combined alfalfa and layer diets on Salmonella colonization. Leghorn hens over 50 wk of age were divided into 12 groups of hens and placed in individual laying cages. One week prior to dietary changes, hens were put on an 8L:16D photoperiod that continued for the 9-d experiment. Hens were challenged orally with 104 cfu of Salmonella Enteritidis (SE) on d 4 of treatment and cultured for SE at the termination of the 9-d study. Two independent experiments were conducted consisting of the following treatment groups: nonfed hens, full-fed standard commercial layer diet, 100% alfalfa meal diet, a 90% alfalfa meal/10% standard commercial layer diet, and a 70% alfalfa meal/30% standard commercial layer diet. When evaluating SE colonization in the ceca (Exp. 1), a reduction (P < 0.05) was seen in the 100% alfalfa meal diet and the 70% alfalfa meal/30% standard commercial layer diet treatment groups when compared with the controls with Log10 values of 0.54, 0.44, and 2.82, respectively. Evaluation of physiological parameters showed the alfalfa treatment groups had reductions (P < 0.05) in weight loss, ovary weight, and feed consumption when compared with the full-fed standard commercial layer diet hens, and these results were comparable with the nonfed hens. In Exp. 2, all of the treatment groups had a reduction (P < 0.05) in SE colonization of the ceca when compared with the controls. There were also similar physiological reductions in weight loss, ovary weight, and feed consumption when birds were fed the alfalfa diets in Exp. 2. These data suggest that alfalfa can potentially be combined with layer ration to limit SE infection and still induce a molt comparable with feed withdrawal.

Animal Feed↗
PubMed2004

Characterization of growth hormone binding sites in granulosa and theca layers at different stages of follicular maturation and ovulatory cycle in the domestic hen.

The currently available evidence points to a possible influence of growth hormone (GH) on avian folliculogenesis, which can be mediated by both hepatic- and ovarian-derived IGF-I. Therefore, the purpose of the present study was to reveal GH-binding sites in granulosa and theca layers of preovulatory follicles and to determine the binding characteristics depending on the degree of follicular maturation and the stage of the ovulatory cycle in the hen. Hens were killed 2 h (stage I), 9 h (stage II), 16 h (stage III), and 23 h (stage IV) after oviposition, and the five largest yellow follicles (from F1 to F5) were removed. GH-binding sites in granulosa and theca layers from F1 to F5 follicles were characterized using a radioreceptor assay. Equilibrium dissociation constants (K(d)) and binding capacities (B(max)) were determined by Scatchard analysis of saturation curves, which revealed a single class of high-affinity GH-binding sites in both theca tissue and granulosa cells. In F1, F2, and F5 follicles, B(max) and K(d) for GH-binding sites in the granulosa layer changed during the ovulatory cycle, decreasing between stages I and III, to increase again at stage IV, with alterations in K(d) being less profound. No significant differences in binding capacities and affinities of GH-binding sites in the theca layer were found between various stages of the cycle. Furthermore, the concentration of GH-binding sites in the granulosa layer rose, whereas that in the theca layer fell with follicular enlargement. These findings indicate the presence of high-affinity GH-binding sites in both granulosa and theca layers of hen preovulatory follicles. Data also demonstrate that GH-binding sites in these tissues are regulated in a tissue-specific manner. Furthermore, the regulation of binding capacity of GH binding in granulosa cells by hormonal factors associated with ovulatory cycle is apparently not dependent on the state of follicular maturation.

Analysis of Variance↗
PubMed2001

Dynamic changes of connexin-43, gap junctional protein, in outer layers of cumulus cells are regulated by PKC and PI 3-kinase during meiotic resumption in porcine oocytes.

Mammalian oocytes are surrounded by numerous layers of cumulus cells, and the loss of gap junctional communication in the outer layers of cumulus cells induces meiotic resumption in oocytes. In this study, we investigated the dynamic changes in the gap junctional protein connexin-43 in cumulus cells during the meiotic resumption of porcine oocytes. The amount of connexin-43 in all layers of cumulus cells recovered from cumulus-oocyte complexes was increased after 4-h cultivation. However, at 12-h cultivation, the positive signal for connexin-43 immunoreactivity was markedly reduced in the outer layers of cumulus cells. When these reductions of connexin-43 were blocked by protein kinase C (PKC) or phosphatidylinositol (PI) 3-kinase inhibitor, networks of filamentous bivalents (i.e., advanced chromosomal status) were undetectable in the germinal vesicle of the oocyte. After 28-h cultivation, when the majority of oocytes were reaching the metaphase I (MI) stage, the connexin-43 in the inner layers of cumulus cells was phosphorylated, regardless of mitogen-activated protein (MAP) kinase activation. These results suggest that the initiation of meiotic resumption, namely, the formation of networks of filamentous bivalents in germinal vesicle, is associated with the reduction of gap junctional protein connexin-43 in the outer layers of cumulus cells via the PKC and/or PI 3-kinase pathway. Moreover, the connexin-43 in the inner layers of cumulus cells is phosphorylated during meiotic progression beyond the MI stage, regardless of MAP kinase activation in cumulus cells surrounding the oocyte.

Animals↗
PubMed1999

Layer-specific horizontal propagation of excitation in the auditory cortex.

Optical imaging was conducted in rat auditory cortex slice preparations to study how horizontal excitation propagates in the cerebral cortex. When a horizontal cut was made between supragranular and infragranular layers, electrical stimulation of layer II/III elicited horizontally propagating excitation in supragranular layers with the same propagating velocities as those seen before a cut was made. Electrical stimulation of layer VI or the border between the white matter and layer VI also elicited horizontally propagating excitation in infragranular layers with the same propagating velocities as those seen before a cut was made. These results suggest that the horizontal propagation of excitation in supragranular and infragranular layers can occur independently in the auditory cortex.

Animals↗
PubMed1996

Effect of periocular humidity on the tear film lipid layer.

The purpose of this study was to determine the relationship between the tear film and humidity by examining whether alterations in periocular humidity influence the thickness of the tear film lipid layer. Thirteen dry eye subjects presenting with a baseline lipid layer thickness of < or = 60 nm were fitted with modified swim goggles in which the right eye (OD) was exposed to conditions of high humidity and the left eye (OS) remained exposed to ambient room conditions. The lipid layer was monitored over a 60-min time course with goggles on and for an additional 60 min following goggle removal. The OD lipid layer increased significantly in thickness within 5 min of exposure to conditions of high humidity (p < 0.0001), reaching a maximum increase of 66.4 nm after 15 min of goggle wear (p < 0.0001). This maximum increase to a lipid layer thickness of 120.5 nm was maintained at the 30- and 60-min goggle time points. No significant change was detected OS. Following goggle removal, OD values declined but remained significantly elevated over the OS lipid layer thickness throughout the 60-min postgoggle period. Moderate to total relief of dry eye symptoms was reported during goggle wear and generally persisted at a reduced level for 1-3 h following goggle removal. Increased periocular humidity results in an increase in tear film lipid layer thickness, possibly by providing an environment that is more conducive to the spreading of meibomian lipid and its incorporation into the tear film.

Adult↗
PubMed1977

Fine structure of the cerebellum of "staggerer-reeler", a double mutant of mice affected by staggerer and reeler conditions. I. The premature disappearance of the external granular layer and ensuing cerebellar disorganization.

It was reasoned that cerebella of mice carrying both staggerer and reeler conditions, called double mutant, might accentuate some of the anomalies observed in single mutants, thus revealing further details otherwise undetectable. As expected, the cerebellar hypoplasia, the paucity of fissures, granule cells and interneurons of the molecular layer, and the external granular layer hypoplasia, common in both staggerer and reeler, were much more pronounced in double mutant. However, the most striking feature of the double mutant cerebellum was the premature disappearance of the external granular layer. The external granular layer is smaller both in staggerer and reeler as compared to the normal but it persists beyond the normal time (around day 15). In double mutant, however, the external granular layer disappeared by day 7 or 8, reducing the density of granule cells even further. This observation was interpreted as indicating that both the staggerer and reeler genes effect the premature disappearance of the external granular layer. Most of the gross cerebellar anomalies in double mutant such as cerebellar hypoplasia, paucity of fissures and Purkinje and Golgi epithelial cell disalignment could be explained as the result of this premature disappearance of the external granular layer. On the other hand, anomalies of Purkinje cells and Bergmann fibers, which are also present both in staggerer and reeler, did not follow the same additive change.

Animals↗
PubMed1997

Do spinal meningiomas penetrate the pial layer? Correlation between magnetic resonance imaging and microsurgical findings and intracranial tumor interfaces.

OBJECTIVE: To study the relationships between spinal dura-arachnoid and tumor-cord interfaces in spinal meningiomas and to investigate whether a disruption of the pial layer and penetration of the tumor in the spinal cord occurs. METHODS: Fifteen patients with histologically proven meningiomas underwent magnetic resonance imaging (MRI) preoperatively. All patients underwent microsurgery. The histological characteristics of the tumors were compared with MRI and microsurgical findings. RESULTS: At surgery, the peritumoral hypointense rim revealed by MRI in 10 of 15 patients corresponded to a well-defined cerebrospinal fluid-containing space confined between the outer arachnoidal layer and the inner leptomeningeal layer. In those patients in whom the hypointense peritumoral rim was absent, the inner layer was either difficult to identify or clearly absent, and the blood vessels were extremely adherent to the tumor, requiring a more cautious dissection. Penetration of the tumors through disruption of the pial surface was not documented. CONCLUSION: Previous anatomic and electron microscopy studies demonstrated, in human spinal meninges, the presence of an intermediate layer attached to the inner aspect of the arachnoid, extending laterally over the dorsal surface of the spinal cord and arborizing over the nerve roots and blood vessels. The intermediate layer is not present in human cerebral leptomeninges. The presence/absence of this layer might explain the hypointense rim detected by MRI and might also explain why no penetration and no peritumoral edema is observed in spinal meningiomas as compared with intracranial meningiomas.

Adult↗
PubMed1993

Successful extended preservation of ischemically damaged pancreas by the two-layer (University of Wisconsin solution/perfluorochemical) cold storage method.

We have demonstrated that a two-layer (University of Wisconsin solution [UW]/perfluorochemical [PFC]) cold storage method restores the function of ischemically damaged pancreas during 24-hr preservation in canine autotransplantation model. The purpose of this study was to examine the possibility of a long-term preservation of the ischemically damaged pancreas by the two-layer (UW/PFC) method. After 60 or 90 min of warm ischemic time, pancreas grafts were preserved by the two-layer (UW/PFC) method or a simple cold storage in UW alone for up to 96 hr. A K value of i.v. glucose tolerance test more than 1.0 2 weeks after autotransplantation was considered successful preservation. After 60 min warm ischemia, limitation of preservation time by the simple cold storage in UW was 24 hr (5/5 100% and 0/5 0%; 24- and 48-hr preservation, respectively). However, the two-layer method made it possible to extend the preservation time up to 48 hr (5/5 100%, 5/5 100%, 2/5 40%, and 0/5 0%; 24-, 48-, 72-, and 96-hr preservation, respectively). After 90 min warm ischemia, the simple cold storage in UW was not effective even for 24-hr preservation (0/5 0%). However, 48-hr preservation was successful by the two-layer (UW/PFC) method (5/5 100%, 5/5 100%, and 0/5 0%; 24-, 48-, and 72-hr-preservation, respectively). After preservation by the two-layer (UW/PFC) method, ATP tissue concentrations of viable grafts were significantly higher compared with nonviable grafts (9.11 +/- 3.05 (n = 22) versus 5.22 +/- 1.02 (n = 13) mumol/g dry wt, P < 0.001). Based on analysis of individual ATP for each graft, if an ATP concentration of 6.0 mumol/g dry weight was determined as a critical value for doing the transplant, sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 84.6%, 91.7%, and 94.3%, respectively. This study clearly demonstrated that 48-hr preservation of the canine pancreas subjected to either 60 or 90 min warm ischemia was successfully achieved by the two-layer (UW/PFC) cold storage method, and ATP tissue concentration at the end of preservation by this method would predict the post-transplant outcome of the ischemically damaged pancreas just prior to transplantation.

Adenosine↗
PubMed2006

Tear meniscus height, lower punctum lacrimale, and the tear lipid layer in normal aging.

PURPOSE: The purposes of this study are to investigate the tear meniscus height (TMH), lipid layer, and critical dimensions of the lower punctum lacrimale (DPL) in normal human subjects over a large age range; and to determine the shape and general characteristics of the lower punctum lacrimale in a normal population. METHODS: TMH and DPL were measured using a graticule set at the eyepiece of a slit lamp biomicroscope (magnification 32x). Lipid layer was assessed by interferometry (Tearscope, Keeler). Only one eye (right) of each subject was assessed. All subjects were normals without any tear-related disorders and/or symptoms. RESULTS: Four hundred forty-four subjects were assessed (268 females, age range, 6-91 years; 176 males, age range, 6-91 years). Mean (+/-standard deviation) TMH in females was 0.19 mm (+/-0.11) and in males was 0.19 mm (+/-0.10). TMH was related to age (x): in females, TMH=0.13+0.0009x (r=0.2393, p<0.001); in males, TMH=0.14+0.0008x (r=0.2492, p<0.001). TMH increased from 0.15 mm (+/-0.06) in the young (<20 years) to 0.21 mm (+/-0.10) in the elderly (>80 years). The punctum was closed in 10.8%, slit shaped in 24.3%, oval in 5.4%, and round in 59.5% of all cases. Mean age and TMH of those presenting with closed puncta was significantly higher than those presenting with open puncta (p<0.001). Mean (+/-standard deviation) area of open puncta was 0.008 mm (+/-0.013) in females and 0.010 mm (+/-0.018) in males. The difference was not significant. Diameter of round puncta was inversely related to age in females (r=-0.4985, n=149, p<0.001) but not within the males. A total of 14.6% of females and 12.5% of males presented with no discernible lipid layer. Lipid layer tended to be thinner in older subjects (one-way analysis of variance, F=6.667, p<0.001). There was no clear relationship between TMH and the lipid layer. CONCLUSIONS: There is a gradual increase in TMH and shift in size and shape of the punctum lacrimale with advancing years. Age-related changes in the lipid layer are expected to reduce tear volume by way of increased evaporation. On balance, it would appear any effects on tear volume by a thinning lipid layer are outweighed by changes in the puncta.

Adolescent↗
PubMed2003

The surface (S-) layer is a virulence factor of Bacteroides forsythus.

Bacteroides forsythus has emerged as a crucial periodontal pathogen with possible implications for systemic disease. The aim of this study was to isolate the S-layer from B. forsythus and examine its virulence potential as a part of efforts to characterize virulence factors of B. forsythus. The role of the S-layer in the haemagglutinating and adherent/invasive activities was evaluated. It was observed that the S-layer alone was able to mediate haemagglutination. In adherent and invasive studies, transmission electron microscopy clearly revealed that B. forsythus cells were able to attach to and invade KB cells, showing the formation of a microvillus-like extension around adherent and intracellular bacteria. The quantitative analysis showed that five different B. forsythus strains exhibited attachment (1.9-2.3 %) and invasion (0.4-0.7 %) capabilities. It was also observed through antibody inhibition assays that adherent/invasive activities of B. forsythus are mediated by the S-layer. Furthermore, an in vivo immunization study adopting a murine abscess model was used to prove that the S-layer is involved in the infectious process of abscess formation. While mice immunized with purified S-layer and B. forsythus whole cells did not develop any abscesses when challenged with viable B. forsythus cells, unimmunized mice developed abscesses. Collectively, the data obtained from these studies indicate that the S-layer of B. forsythus is a virulence factor.

Abscess↗
PubMed2002

Ion-acoustic compressive and rarefactive double layers in a warm multicomponent plasma with negative ions.

Propagation of ion-acoustic double layers has been studied in plasma consisting of warm positive- and negative-ion species with different masses, concentrations, and charge states along with electrons with two-electron temperature distributions. It is found that there exist two critical concentrations of negative ions, alpha(R) and alpha(Q). One of them (alpha(R)) generally decides the existence of the double layer, whereas the other one (alpha(Q)) decides the nature of the double layer. It is found that the system supports ion-acoustic double layers only when the negative-ion concentration (alpha) is greater than the critical concentration alpha(R). It is also found that below the critical concentration alpha(Q), compressive double layers exist and above it rarefactive double layers exist. For some values of cold-electron concentrations (mu) it is found that if the temperature of the negative-ion species is higher than the positive-ion species, then the system supports compressive double layers for all values of alpha lying in the range 0<alpha<alpha(Q). The dependence of the critical concentrations on the temperatures of the two-ion species and on the concentration of cold electrons has also been investigated.

Journal Article↗
PubMed2006

Wannier-based definition of layer polarizations in perovskite superlattices.

In insulators, the method of Marzari and Vanderbilt [Phys. Rev. B 56, 12 847 (1997)] can be used to generate maximally localized Wannier functions whose centers are related to the electronic polarization. In the case of layered insulators, this approach can be adapted to provide a natural definition of the local polarization associated with each layer, based on the locations of the nuclear charges and one-dimensional Wannier centers comprising each layer. Here, we use this approach to compute and analyze layer polarizations of ferroelectric perovskite superlattices, including changes in layer polarizations induced by sublattice displacements (i.e., layer-decomposed Born effective charges) and local symmetry breaking at the interfaces. The method provides a powerful tool for analyzing the polarization-related properties of complex layered oxide systems.

Journal Article↗
PubMed1992

Dormancy of the barley grain is correlated with gibberellic Acid responsiveness of the isolated aleurone layer.

The relationship between barley grain dormancy and gibberellic acid (GA(3)) responsiveness of aleurone layers has been investigated. Barley (Hordeum distichum L. cvs Triumph and Kristina) grains were matured under defined conditions in a phytotron. Grains of Triumph plants grown under long-day/warm conditions had lower dormancy levels than grains of plants grown under short-day/cool conditions. Aleurone layers isolated from grains of long-day Triumph plants secreted more alpha-amylase and had a higher responsiveness to GA(3) as measured by alpha-amylase secretion. Storage of the grains increased both the percentage of germination and the responsiveness of the aleurone to GA(3). Use of different sterilization methods to break dormancy confirmed the correlation between germination percentage and aleurone layer GA(3) responsiveness. The response of embryoless Triumph grains to GA(3) was lower than that of the isolated aleurone layers, suggesting a role of the starchy endosperm in regulating the GA(3) response of the aleurone layer. Grains of the cultivar Kristina harvested from short day- and long day-grown plants lacked dormancy, and their isolated aleurone layers had a similar responsiveness to GA(3) as measured by alpha-amylase secretion. The data indicate that the physiological state of the aleurone layers contributes to the percentage germination of the grains.

Journal Article↗
PubMed1979

Abscisic Acid localization and metabolism in barley aleurone layers.

Aleurone layers of Hordeum vulgare, cv. ;Himalaya' took up [(14)C]-abscisic acid (ABA) when incubated for various times. Radioactivity accumulated with time in a low speed, DNA-containing pellet accounting for 1.6 to 2.3% of the radioactivity recovered in subcellular fractions at 18 hours. Thin layer chromatography of ethanolic or methanolic extracts of the cytosol, which contained greater than 95% of the radioactivity taken up by layers, revealed that labeled ABA was metabolized to phaseic acid (PA) and 4'-dihydrophaseic acid (DPA) and three polar metabolites Mx(1), Mx(2), and Mx(3). ABA was not metabolized by endosperm, incubated under conditions used for layers, indicating that metabolism was tissue-specific. Layers metabolized [(3)H]DPA to Mx(1) and Mx(2). ABA, PA, and DPA-methyl ester and epi-DPA-methyl ester inhibited synthesis of alpha-amylase by layers incubated for either 37 or 48 hours. These layers converted the methyl DPA and epi-methyl-DPA esters to their respective acids. DPA did not inhibit Lactuca sativa germination or root and coleoptile elongation of germinating Hordeum vulgare seeds, or coleoptile elongation of germinating Zea mays seeds.

Journal Article↗