Basal Tissues Research Articles

High-level tuber expression and sucrose inducibility of a potato Sus4 sucrose synthase gene require 5' and 3' flanking sequences and the leader intron.

The 3.6 kb of 5' flanking sequence, leader intron, and 0.7 kb of 3' sequence from the potato sucrose synthase gene Sus4-16 are sufficient to direct high-level expression in developing tubers, in basal tissues of axillary buds and shoots, and in meristems and caps of roots, and to confer sucrose inducibility in leaves. By examining a series of deletion and substitution constructs in transgenic potato plants, we found that this pattern of expression requires 5' flanking sequences both upstream and downstream of position -1500 and that sequences between positions -1500 and -267 are essential for sucrose induction. Replacement of the native 3' sequence with the nopaline synthase 3' sequence resulted in the loss of sucrose inducibility and of expression in basal tissues of axillary buds. A general decrease in expression in other tissues was also observed. Removal of the 1612-bp leader intron also had a dramatic effect on both the pattern and level of expression.

Carotenoid composition and its relationship to chlorophyll and D1 protein during leaf development in a normally senescing cultivar and a stay-green mutant of Festuca pratensis

Chlorophyll and carotenoid were measured with reference to the developmental gradient along the expanding fourth leaf of Rossa, a normally yellowing cultivar of Festuca pratensis, and of a mutant genotype Bf993 which is unable to degrade pigments and associated thylakoid proteins during foliar senescence. Although pigment levels were highest in the central, mature portion of the leaf, there were nevertheless readily detectable amounts of chlorophyll and carotenoid even in basal tissues enclosed in the sheaths of older leaves. Carotenoid compositions were the same in all the tissues except the senescent tissue at the leaf tip. Here chlorophyll to carotenoid ratio decreased in Rossa but along the young leaf tissue of this genotype and throughout the leaf of Bf993 this ratio was constant. Amounts of D1 protein, associated with the Photosystem II reaction centre, were correspondingly retained to a somewhat greater extent in senescing tissue of Bf993 but surprisingly, given the expression of the genetic lesion in a delayed senescence, amounts of the protein were lower in young tissue from the stay-green mutant than in the normal genotype. When the leaf of Rossa was allowed to senesce until the entire blade was yellow there were marked changes in carotenoid composition, and chlorophyll degradation products accumulated. Any increase in zeaxanthin was slight and there was no evidence to suggest operation of a xanthophyll cycle.

Excised Tassel-Seed Tunicate (Ts-5 Tu) Kernels as a Model In vitro System for Studying Amino Acid Metabolism in Developing Maize Seeds

Summary Previous studies suggest that nitrogenous transport compounds may be metabolized in the pedicel (basal maternal tissue) of the developing maize ( Zea mays L.) kernel. In this report, excised tassel-seed tunicate ( Ts-5 Tu ) kernels were tested as a model in vitro kernel system to study the metabolic fate of [ l4 C]aspartate within the pedicel and the endosperm. Glume-covered kernels of Ts-5 Tu maize are born on individual elongated stalks and can be removed from the parent plant without damage to the basal kernel tissues. Radiolabeled aspartate supplied to excised Ts-5 Tu kernels in a 30-min pulse was rapidly metabolized within the pedicel, with 60 % of the 14 C recovered in the acidic (organic-acid-containing) fraction at the beginning of the chase period. By 1 h into the chase period, both glutamine and glutamate were more heavily labeled than aspartate. In the endosperm, 60 % of the ethanol-soluble, aspartate-derived 14 C was recovered in the basic (amino acid-containing) fraction, 35% in the acidic fraction, and the remainder in the neutral (sugar-containing) fraction. Radioactivity in glutamate plus glutamine accounted for 70% of the 14 C contained in the basic fraction of the endosperm. Inclusion of 2 mM methionine sulfoximine, an irreversible inhibitor of glutamine synthetase (GS), had little effect on pedicel aspartate catabolism but did inhibit incorporation of aspartate-derived 14 C into glutamine in the pedicel, resulting in more 14 C being taken up by the endosperm as organic acids and less being incorporated into the prolamin fraction. It was concluded that the results obtained using Ts-5 Tu kernels incubated in vitro reflect more closely what occurs in the intact plant than those obtained with cob-borne kernels. The role of pedicel-amino-acid metabolism in maize-kernel nitrogen assimilation is also discussed.

Nerve growth factor induces trkA mRNA expression in cultured basal forebrain cholinergic neurons from 17-day fetal rats

We first examined the basal forebrain tissues for developmental changes in expression of the high-affinity NGF receptor ( trkA) gene. Our reverse transcriptase polymerase chain reaction (RT-PCR) analysis showed that trkA mRNA is present in those tissues of postnatal rats, but not in those of fetal rats. Then we determined the effect of NGF on trkA gene expression in serum-free cultures of basal forebrain neurons from 17-day fetal rats. NGF was found to induce trkA mRNA 36 h after the addition of NGF, while no trkA mRNA was detected in the absence of NGF.

The effect of doxorubicin on the unimpeded eruption rates of rat mandibular incisors

We examined the effects of daily injections of doxorubicin, an anti-tumor drug, on unimpeded eruption rates, pulp cells, odontoblasts, periodontal ligament and dentine formation in the rat mandibular incisor. The experimental animals were intraperitoneally injected with 5 mg of doxorubicin/kg body weight/day for a period of 7 days. The eruption rates decreased gradually; and on the seventh day, the mean eruption rate had decreased to 14% of the control value. In addition, we noticed marked destruction of pulp cells and periodontal cells at the basal region of the incisor. The amount of dentine formation was measured using the tetracycline labeling method, but significant decreases in dentine formation were not observed. These results suggest that destruction of the basal tissues is related to inhibition of incisor eruption rates, but that tooth eruption is not related to dentine formation.

局所機能圧・負担圧に関する基礎的研究 ＩＩ‐３． 上顎総義歯の側方こう合位について

We previously studied distribution of stress-bearing at the centric occlusion in basal tissues of complete maxillary denture. Furthermore, we studied it at each occlusion on the right side, the right rubber molar, the right resin molar and bilateral balance.The results were as follows:1. Right side occlusion (right)Stress-bearing of the residual ridge, basal margin, buccal region, palate and post dam in the centric occlusion increased especially from the basal margin to the palate including the incisive papilla, but decreased in range from the balance basal margin to the palate.2. Right rubber molar occlusion (rubber)Comparing stress-bearing of the residual ridge, basal margin, buccal region, palate and post dam in the centric occlusion with that on the right, there was significant elevation from the masticatory basal margin to the palate, but reduction in the incisive papilla and median palate.Stress-bearing from the non-masticatory basal margin to the palate significantly decreased except for the maxillary tubercle, buccal region and basal margin.3. Right resin molar occlusion (resin)Comparing stress-bearing in the centric occlusion with that on the right and on rubber, there was an elevation ranging from the masticatory basal margin to the palate, but reduction in the median palate. Stress-bearing of the incisive papilla was markedly lower than that on the centric occlusion and on the right, but higher than rubber.The stress-bearing from the non-masticatory basal margin to the palate decreased. It was at a negative level in maxillary mucosa and was within normal limits in maxillary bone.

Enhanced degradation of collagen within apical vs. basal wall of ovulatory ovine follicle.

Electron microscopic examination of ovulatory ovine follicles indicated that dissolution of thecal collagen was enhanced along the follicular circumference adjacent to the ovarian serosa. Concentrations of hydroxyproline were correspondingly lower within apical than basal tissues. Collagenolytic activity of tissue homogenates and extracts was assessed by monitoring radioactive peptide release from cocultured collagen fibrils. Collagenase inhibitors were separated from enzyme by sequential extraction of follicular homogenates with detergent and heating. Enzymatic activities of homogenates and heat extracts of apical and basal tissues increased toward ovulation. A distinction between apex and base was not attributed to significant differences in homogenates; however, collagenolytic activity of heat extracts of apical tissue was selectively elevated (i.e., extraction was evidently required to effectively dissociate collagenase from thecal fibrils, making more enzyme available for substrate digestion). Activity of detergent extracts was restored by dithiothreitol and iodoacetamide (which inactivate tissue inhibitors of metalloproteinases), and collagenolysis induced by heat extracts was augmented by aminophenylmercuric acetate (a stimulator of latent collagenases). Nonetheless, variations between apex and base invoked by these compounds were relative. It therefore appears that active collagenase is more tightly bound within the extracellular matrix of the follicular apex than enzyme associated with basal tissue. This phenomenon might serve to preferentially favor enzymatic catabolism of collagen in that region, thereby dictating the ovarian site of follicular rupture.

Sugar Uptake and Metabolism in the Developing Endosperm of Tassel-seed Tunicate (Ts-5 Tu) Maize

Factors regulating assimilate transport into developing maize (Zea mays L.) kernels have been difficult to determine because of the structural complexity of basal kernel tissues and the damage that results from tissue dissection. The sensitivity of maize kernels to experimental manipulation is such that substantial maternal tissue is required to support kernel growth in vitro. Consequently, sugar transport experiments with isolated seed tissues or detached kernels have not unequivocally demonstrated how sugar transport occurs. In the present study, Tassel-seed Tunicate (Ts-5 Tu) maize kernels were investigated as a model system for introducing test solutions into the pedicel apoplast with minimal wounding. Transpiration in leafy glumes drew (14)C-sugar solutions up the 8- to 10-millimeter-long pedicel stalks into the basal endosperm transfer cell region. (14)C from fructose was incorporated into starch for 8 days. Sugar uptake into endosperm and embryo tissue showed specificity and inhibitor sensitivity. In particular, p-chloromercuribenzene sulfonate partially inhibited fructose uptake into the endosperm but had no effect on the metabolic conversion of that fructose that entered the endosperm. These results are consistent with active, carrier-mediated sugar transport, but a definitive determination would require more detailed tissue analysis. We propose that further refinement of the incubation solution may allow long-term kernel growth without cob tissue and thus provide a more precise determination of which maternal factors influence seed development.

Influence of nerve growth factor on the fetal basal forebrain tissues transplanted into the brain of adult rats.

脳内の神経成長因子 (NGF) が, 前脳基底部や中隔のコリン系ニューロンの栄養因子として作用することが知られている. 本研究では成熟ラットの側脳室に胎仔の前脳基底部を含む組織を移植し, 更にNGFを持続投与した. 移植組織のコリン系ニューロンをAcetylcholinesterase (AChE) の組織化学染色により観察し, AChE陽性ニューロンの大きさを測定した. 移植組織のAChE陽性ニューロンの大きさは, NGF20μg/ml投与群 (0.01μg/hr, 総量3.36μg) で, 対照群より有意に大きくNGF100μg/ml (0.05μg/hr, 総量16.8μg) 群では小さい値を示した. このことは移植組織のAChE陽性ニューロンの成長をNGFが促進すること, さらにNGFは用量依存的にニューロンの成長を促進するのではなく, 成長促進に適当なNGFの濃度範囲が存在する可能性を示唆する. 一方, 側脳室にNGFを投与すると, ラットの体重増加が抑制される現象が認められた. 成熟ラットにおいて, NGFが体重増加を抑制する現象を認めた報告は本研究が初めてであり, さらに検討する必要がある.

Rooting herbaceous cuttings ofGenista monospermaLam.: Seasonal fluctuations in phenols affecting rooting ability

Genista monosperma Lam. can be propagated by herbaceous cuttings, but seasonal fluctuations in rooting ability can be observed. These appear to be correlated with the ratio of two main endogenous phenols, 3-hydroxymandelic acid and luteolin-7-O-glucoside, accumulating in the tissues, the first acting as an inhibitor and the second as a promoter of adventive rhizogenesis. Their biological activity has been tested and evaluated on G. monosperma in vitro micropropagated explants. The inhibitory effect on rooting of 3-hydroxymandelic acid accumulation in cutting basal tissues can be lessened by a soaking treatment with distilled water, applied to the basal part of the cuttings before planting in rooting benches.

Protein phosphorylation in the organ of Corti: Differential regulation by second messengers between base and apex

Major aspects of cellular physiology are regulated by the phosphorylation state of proteins through the action of protein kinases and protein phosphatases. Phosphorylation of proteins by endogenous protein kinase activity was assayed in homogenates from guinea pig inner ear tissues with [γ- 32P]ATP. Phosphoproteins showed distinct distributions in organ of Corti, lateral wall and spiral ganglion.In the organ of Corti, several protein kinase activities were distinguished by their activation by appropriate agonists: protein kinase C, calmodulin-dependent protein kinases and cyclic nucleotide-dependent protein kinases. Twelve putative substrates for these kinases were identified in organ of Corti on the basis of increased 32P-incorporation with addition of lipids, calmodulin, and cyclic nucleotides, respectively. In addition, differences in phosphorylation were observed between the base and apex of the organ of Corti. 32P-incorporation into proteins of molecular weights between 45 and 100 kDa was significantly higher in apical tissue than in tissue from the base. In contrast, phosphate incorporation into proteins of around 29 kDa was much lower in apical tissues than in basal tissues. Furthermore, labeling of both the high and low molecular weight proteins from the apex but not the base markedly increased in response to calcium. These data indicate the presence of differential modes of regulation that may underlie structural and functional gradients along the sensory epithelium.

Plants can grow on internal water

Abstract. Water uptake is required when plants enlarge but growth may also occur when no external water is present. To determine whether this growth also depends on water, we studied etiolated seedlings of soybean (Glycine max L. Merr.) deprived of external water by transplanting to vermiculite of low water content or by transferring to water‐saturated air. When the external water supply was decreased or removed, the roots continued to grow rapidly but the stems abruptly decreased in growth (in 1 min) and continued to grow slowly. The stem tissues gained water content in the upper elongating region and lost water content in the basal region. Removal of the basal stem caused growth to slow further. When all tissues surrounding the stem elongating region were removed simultaneously, stem growth decreased abruptly to near zero. Control experiments showed that the decreased growth was not caused by wounding or the removal of the auxin or nutrient supply. It is concluded that growth always depended on a source of water and, when external supplies were absent, internal water was mobilized to enlarging tissues of shoots and roots mostly from the basal stem tissues in these seedlings.

Partitioning and distribution of 14C in Boronia megastigma nees

Summary In order to test the nutrient diversion hypothesis in the woody shrub Boronia, plants were fed 14CO2 every 10 days during the first 70 days of flower-promoting conditions. Basal and apical tissues were harvested from the fed lateral 24 h after labelling. The samples were partitioned first to remove chloroform soluble material. Amino acids, organic acids and phosphates, and sugars were extracted into alcohol, while proteins, starch, and structural material remained insoluble. On a lateral of Boronia the first flower buds normally initiate approximately three to four nodes below the apex. This is associated with the cessation of leaf expansion in the subtending leaf. Prior to flower bud initiation it was found that there was an increase in the sink strength of the subtending leaf. This could be seen by the ratio of dpm in apical tissue compared with the basal tissue. In addition there was an increase in the percentage of 14C partitioned into the sugar, amino acid, and protein fractions in both basal and apical tissue.

Influence of cherry rootstock on the cold hardiness of twigs of the sweet cherry scion cultivar

Scion twig tissue of the sweet cherry cultivars ‘Hedelfingen’, ‘Napoleon’ and ‘Gold’ were subjected to cold hardiness evaluations in the late fall (November 21, 1984) and early spring (March 1, 1985) of the same dormant season. ‘Hedelfingen’ and ‘Gold’ were grafted to the rootstocks ‘Colt’ and ‘Mazzard’. At sampling, the twig tissues were stratified statistically as to apical and basal positions on the twig. A comparison of scion tissues grown on the rootstocks in common (‘Mazzard’ and ‘Colt’) showed a scion cultivar hardiness ranking of ‘Gold’ > ‘Hedelfingen’ > ‘Napoleon’. Separate evaluations included two other rootstocks: ‘MxM-39’ for ‘Gold’ and ‘Hedelfingen’, and ‘Mahaleb’ for ‘Napoleon’. Rootstock influence on scion twig tissue showed that ‘Gold’ and ‘Hedelfingen’ produced the following hardiness ranking: ‘MxM-39 > ‘Mazzard’ > ‘Colt. For ‘Napoleon’ the ranking was: ‘Mahaleb’ > ‘Colt’ > ‘Mazzard’. Basal tissues on sampled twigs were more hardy than apical tissues on the dates sampled.

Cryptic floral determination: Stem explants from vegetative tobacco plants have the capacity to regenerate floral shoots

The developmental fates of shoots regenerated in culture and in situ by stem tissues of Nicotiana tabacum cv. Wisconsin 38 from different positions along the main axes of plants at different ages have been characterized. It was expected that explants from vegetative plants would not have the capacity to produce floral shoots. Contrary to the expected result, a small percentage (about 0.2%) of the shoots formed from cultured stem explants taken from young, vegetative plants were floral, i.e., produced a small number of nodes and then a flower. A larger percentage (about 2%) of the shoots formed by explants from the same region of plants which had flowered were floral. The largest percentage (76%) of floral shoots arose from explants taken from the inflorescence. Internode cells which were stimulated to divide and undergo organogenesis in situ after decapitation of the plant also produced few-noded, floral shoots with apical internode tissues producing many such floral shoots and basal internode tissues producing few such floral shoots. These results indicate that the capacity to form a flower is a visible expression of a cryptic developmental state which is quantitatively but not qualitatively controlled in time and space.

Fructans in Forage Grasses with Varying Degrees of Coldhardiness

Summary Changes in WSC content and molecular size profile of fructan in perennial and annual forage grasses ofvarying coldhardiness were determined during the fall months of 1987. Phleum, Phalaris and Bromus spp. are hardier than Dactylis, Festuca and Lolium spp. The concentration of WSC in herbage on August 5 was much higher in annual ryegrass than perennials. There was no linear relationship between the WSC content in basal 5 cm top tissues and the coldhardiness. With TLC, a series of low-DP fructans were detected in basal top tissues of Bromus, Festuca and Lolium spp., but only very small amounts occurred in Phleum, Phalaris and Dactylis . There was little change in low DP fructans (DP 3 to 10) during the fall season. HPLC showed four distinct types of molecular size distribution pattern of fructans: Phleum-Phalaris type, Dactylis type, Bromus type and Festuca-Lolium type. A typical change in HPLC profile in hardy grasses during the fall months was a decrease in high-DP fructan (DP ≥ 35) and an increase in medium-DP fructan (DP 11 to 34).

Biochemical Parameters in various Sections of bovine Corpora lutea graviditatis during the Course of Pregnancy*

The enzyme activities of glutathione peroxidase (GPO) with cumenehydroperoxide (cumene-OOH) and H2O2 as substrates, glutathione-S-transferase (GSH-S-T) with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate, phosphofructokinase (PFK) and succinate dehydrogenase (SuDH) were determined for months 1 through 9 of pregnancy in the basal and peripheral sections of the corpora lutea graviditatis of Holstein-Frisean cows. The concentration of reduced glutathione (GSH) was simultaneously measured in these tissue sections. Substantial topographical differences were apparent in the enzyme activities. GPO and GSH-S-T showed activity differences during the course of pregnancy. During the 2nd month of pregnancy, minimal values for the activity of cytoplasmic GPO were observed in the basal areas. The cytoplasmic GPO in the peripheral areas displayed a contrasting dynamic with maximal values during the 6th month. GSH-S-T activities in basal and peripheral tissues appeared similar. GPO activities with H2O2 as substrate, likewise, displayed similar courses of activity in both tissue localizations. SuDH was more active in the peripheral than in the basal area. The activity of PFK displayed just the reverse course. The concentration of GSH in the peripheral area was not higher than in basal area.

Fructan in winter wheat, triticale, and fall rye cultivars of varying cold hardiness

Eight winter wheat, one triticale, and three fall rye cultivars with mean lethal temperature (LT50) values from −5.5 to −20.0 °C were harvested in late November and analyzed for fructans. Fructose, sucrose, and oligofructans with a degree of polymerization (DP) of 6 or lower were found in all cultivars. The concentration of DP 4 fructan was higher than that of DP 5 in winter wheat and triticale, while the opposite trend was found in fall rye. Fructans with a DP of 7 or higher (high DP fructans) were found at high concentrations in hardy winter wheat and fall rye. The high DP fructan was very low or negligible in the least hardy winter wheat cultivar 'Super X'. Fructans in winter cereals consisted mainly of inulin type with a β-2-1 linkage. The activity of phlein sucrase, which catalyzes synthesis of phlein, was much lower in winter cereals compared with phlein-rich grasses. It was concluded that high DP fructans of inulin type in basal top tissues of winter cereals were more closely associated with freezing resistance than low DP fructans.

Evidence that hypothalamic neuropeptide Y secretion decreases in aged male rats: implications for reproductive aging.

The decrease in circulating testosterone and LH titer that occurs in aged male rats may in part be a consequence of decreased excitatory neurochemical signals that promote the episodic discharge of LHRH from the hypothalamus. In view of evidence that neuropeptide Y (NPY) stimulates the release and potentiates the action of LHRH on LH secretion, the present studies investigated age-related changes in the concentrations of NPY in individual hypothalamic nuclei and in the ability of hypothalamic tissues to release NPY in vitro. Compared with tissues of 2.5-month-old male rats, medial basal hypothalamic tissues of 13-month-old rats released significantly less NPY in response to K+ depolarization. In contrast, K+-evoked LHRH release from the same tissues was unimpaired. Aged male rats also exhibited markedly reduced concentrations of NPY in the median eminence and in the arcuate, medial preoptic, suprachiasmatic, paraventricular, dorsomedial, and ventromedial hypothalamic nuclei, which are sites of NPY perikarya and nerve terminal networks. These neurochemical changes occurred in association with decreased serum testosterone and LH levels. These findings demonstrate a widespread age-related decline in NPY levels and release in the hypothalamus, which may be responsible for the reduction in testosterone secretion and may contribute to the decline in reproductive function in aged male rats.

Identification and quantitation of indole-3-acetic and abscisic acids in the cambial region of Quercus robur by combined gas chromatography-mass spectrometry.

A technique is described for the rapid purification of indole-3-acetic acid (IAA) and abscisic acid (ABA) from small quantities of the basal trunk cambial region tissues of 34-year-old trees of Quercus robur L. Mass spectra of IAA and ABA obtained from the purified extracts provide the first reported unequivocal identification of endogenous IAA and ABA in the cambial region of a hardwood species. By use of the combined gas chromatography-mass spectrometry technique of multiple ion monitoring, with deuterated analogs as internal standards, it was shown that the levels of IAA in the cambial region tissues varied from ~1 to ~20 microg g(-1) and those of ABA from ~1 to ~5 microg g(-1) dry weight during the growing season. The high levels of IAA are similar to those found in the newly differentiating xylem tissues of softwoods.