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At least 343 records · Page 19Linked to original sources
PubMed1996

Isolation and characterization of two cDNA clones for mRNAs that are abundantly expressed in immature anthers of rice (Oryza sativa L.).

The relationship between the length of anthers and the stage of development of microspores was examined in rice (Oryza sativa L. cv. Hayayuki). Anthers of < or = 2 mm and 2.1-2.2 mm in length and those ready to dehiscence were determined to be at the uninucleate, binucleate and trinucleate microspore stage, respectively. Two cDNAs (YY1 and YY2), representing genes that are specifically expressed in anthers at the uninucleate microspore stage, were isolated and characterized. YY1 cDNA encoded an open reading frame of 95 amino acids. Eight cysteine residues with the potential to form disulfide bridges were present in the amino acid sequence. There was a hydrophobic region at the N-terminus of the putative protein, suggesting that the YY1 protein might be secreted. This cysteine motif and the hydrophobic N-terminus are conserved among products of several anther-specific genes or cDNAs isolated from various plant species. These proteins are thought to form a superfamily of proteins that are confined to anthers. The YY1 transcript was localized in the tapetal cells and the peripheral cells of the vascular bundle. YY2 cDNA encoded an open reading frame of 389 amino acids and the deduced amino acid sequence exhibited substantial homology to that of chalcone synthase. Expression of YY2 mRNA was confined to the tapetal cells. The genes correspond to YY1 and YY2 cDNAs were shown to exist as single copies in the rice genome.

Amino Acid Sequence↗
PubMed1995

Expression of the rice Osgrp1 promoter-Gus reporter gene is specifically associated with cell elongation/expansion and differentiation.

To study the expression and regulation of a rice glycine-rich cell wall protein gene, Osgrp1, transgenic rice plants were regenerated that contain the Osgrp1 promoter or its 5' deletions fused with the bacterial beta-glucuronidase (GUS) reporter gene. We report here a detailed histochemical analysis of the Osgrp1-Gus expression patterns in transgenic rice plants. In roots of transgenic rice plants, GUS expression was specifically located in cell elongation and differentiation regions, and no GUS expression was detectable in the apical meristem and the mature region. In shoots, GUS activity was expressed only in young leaves or in the growing basal parts of developing leaves, and little GUS activity was expressed in mature leaves or mature parts of developing leaves. In shoot apices, GUS activity was detected only in those leaf cells which were starting to expand and differentiate, and GUS expression was not detected in the apical meristem and the young meristematic leaf primordia. GUS activity was highly expressed in the young stem tissue, particularly in the developing vascular bundles and epidermis. Thus, the expression of the Osgrp1 gene is closely associated with cell elongation/expansion during the post-mitotic cell differentiation process. The Osgrp1-Gus gene was also expressed in response to wounding and down-regulated by water-stress conditions in the elongation region of roots. Promoter deletion analysis indicates that both positive and negative mechanisms are involved in regulating the specific expression patterns. We propose a simple model for the developmental regulation of the Osgrp1 gene expression.

Base Sequence↗
PubMed1996

Common occurrence of homologues of petunia glycine-rich protein-1 among plants.

The presence of specific glycine-rich proteins (GRP) related to petunia GRP1 (ptGRP1) was examined in three species of monocots (wheat, barley and maize) and five species of dicots (rape, turnip, soybean, crabapple and tomato). Protein blot analysis showed that anti-ptGRP1 antibody cross-reacted with a single different polypeptide in all species except maize. The molecular mass of these polypeptides ranged from 14 to 55 kDa. Tissue-print immunoblots of rape petioles and stems showed that the rape ptGRP1 homologue, like ptGRP1, is primarily located in the vascular tissue, and that its expression decreases with developmental age of the tissue. In barley, the ptGRP1 homologue is found in leaf vascular bundles, and may also be present in the surrounding bundle sheaths. Unlike the dicots examined, expression of the protein did not appear to decrease significantly with developmental age.

Blotting, Western↗
PubMed1992

Analysis of the region in between two closely linked patatin genes: class II promoter activity in tuber, root and leaf.

From a potato genomic library a phage lambda clone was isolated that carried nucleotide sequences of two patatin genes, thus demonstrating a close physical linkage between these two members of the patatin gene family. Sequence and restriction analysis showed the genes to be oriented in tandem. The more upstream gene was a pseudogene truncated at the 3' end, whereas the downstream gene was a class II patatin gene. In addition to a 208 bp fragment also present in patatin class I promoters, the region in between both genes contained various direct repeats also found in other patatin genes. To study the promoter activity of this intergenic region, a 2.78 kb fragment was transcriptionally fused to the beta-glucuronidase gene and reintroduced into potato cultivar Bintje. Histochemical analysis revealed expression in the outermost layer of cells of the cortex, in the tuber phellogen, in or around the root vascular system, and also in the abaxial phloem layer of the vascular bundle in leaves.

Amino Acid Sequence↗
PubMed1992

Reconstruction of the proximal femur with a vascular pedicle iliac crest graft after tumour resection.

A useful method of reconstruction of the proximal femur after tumour resection is described. An anterior iliac crest bone graft with an intact vascular supply based on the deep circumflex iliac vascular bundle is used to fill the bone defect. It is swung down to the femur behind the iliopsoas muscle and locked into place in the femur. Sixteen cases of locally aggressive tumours have been resected and reconstructed by this method. Follow-up for five to eight years shows good reconstitution of the femur and hip function without recurrence.

Adult↗
PubMed1982

Histotopography and ultrastructure of the thin limbs of the loop of Henle in the hamster.

In the kidney of the Syrian hamster the descending thin limbs of both the short and long loops of Henle are not spatially separated from each other and descend between the vascular bundles. Ultrastructurally, five different epithelial types are distinguished in the thin limbs of the short and long loops of Henle. Short loops possess only a descending thin limb with a simply organized epithelium (type 1). Long loops comprise an upper and a lower part of the descending thin limb and the ascending thin limb. The upper part of the long descending thin limb is equipped with a complex and highly interdigitating epithelium with shallow junctions (type 2), which gradually transforms into the simple noninterdigitating type-3 epithelium of the lower part. In a minor portion of long descending thin limbs, however, the upper part begins with an even more complexly organized epithelium (type 2a) than type 2. Type-2a epithelium is conspicuously thicker and possesses a more elaborate mode of cellular interdigitation. Along the descent of this tubular part through the inner stripe of the outer medulla, type-2a epithelium transforms into type-2 epithelium. It is suggested that the long descending thin limbs, which start with type-2a epithelium, belong to the longest loops. The type-4 epithelium of the ascending thin limbs is characterized by flat and extensively interdigitating cells with shallow junctions. The unique pattern of the type-2a epithelium favors the assumption that solute secretion essentially contributes to the increase in concentration of tubular fluid in long descending thin limbs.

Animals↗
PubMed1993

Isolation and characterization of novel nodulin cDNAs representing genes expressed at early stages of soybean nodule development.

We took advantage of a subtractive hybridization procedure to isolate a set of cDNA clones of nodule-specific genes (nodulin genes) from developing soybean root nodules. Single-stranded 32P-labelled cDNA synthesized from nodule poly(A)+ RNA was hybridized with a large excess of uninfected root poly(A)+ RNA. Unhybridized cDNA was selected and used to screen nodule cDNA libraries. By this procedure we isolated several novel nodulin cDNA clones together with most of the nodulin cDNAs previously described. Four novel nodulin genes, which were expressed long before the onset of nitrogen fixation, were further characterized. GmN#36 and GmN#93 transcripts appeared in the roots less than 3 days after sowing and inoculation with Bradyrhizobium, but GmN#36 transcripts were also detected at very low levels in the stems of uninfected plants. Transcripts of GmN#315 and GmN#70 first appeared at 6-7 days, just before nodule emergence. Amino acid sequences of the predicted products of GmN#36, GmN#93 and GmN#70 exhibited no significant homology to proteins identified so far. The GmN#315 encoded protein has a limited but significant homology to some plant cyanins, suggesting that it is a metal-binding glycoprotein. In situ hybridization studies revealed that GmN#36 transcripts first appeared in the pericycle cells of the root stele near the infected site. During nodule emergence they were found in a few cell layers surrounding the vascular strands connecting the nodule meristem with the root stele, and in mature nodules they were present specifically in the pericycle cells in vascular bundles. These observations led us to hypothesize that GmN#36 gene products play a role in the transport and/or degradation of photosynthate. On the other hand, GmN#93 transcripts first appeared in the primary nodule meristem just below the root epidermis. In mature nodules they were only present in the infected cells.

Amino Acid Sequence↗
PubMed1988

Mammalian renal modifications in dry environments.

The literature on the role of the kidney and renal morphological modifications in places of limited water supply is reviewed. The anatomical structures for urine concentration found in animals living in desert or arid environments, although not all occurring in one particular animal, are wide medullae, long loops of Henle, long proximal tubules, long collecting tubules, small renal corpuscles, extension of the renal pelvis, well developed elongated papillae, occurrence of giant vascular bundles, specialized ultrastructure of Henle's loops, epithelial changes in the collecting tubule, zonation of the vasa recta and peculiarity of the arterial supply to the kidney. The renal renin content is moderately high in these species. The renin-angiotensin-aldosterone system is very active, retaining Na+ with water. The urine is concentrated at the expense of other electrolytes. Both the renal blood and urinary flow rates are lower than in species with access to unlimited water supply. The juxtaglomerular apparatus components are topographically intimate for effective tubuloglomerular autoregulation of renal blood flow.

Acclimatization↗
PubMed1992

Brassica anther-specific genes: characterization and in situ localization of expression.

A cDNA library of Brassica napus (cv. Westar) was constructed using poly(A)+ RNA isolated from developing anthers of flower buds 2-3 mm in length. Differential hybridization, using cDNA probes complementary to poly(A)+ RNA from developing anthers or seedlings, was used for initial screening. In addition to Southern and Northern blot analyses of selected clones, RNA-PCR assays and in situ hybridization were used to study the temporal and spatial gene regulation in anthers at the transcriptional level. Five independent cDNA clones, showing no cross-hybridization to one another, were characterized, and their expression patterns could be grouped into three distinct categories. Two cDNA clones, BA112 and BA158, are tapetum-specific: the corresponding mRNAs accumulate in young anthers and decline as the tapetum cells degenerate later in anther development. The transcripts represented by BA54 and BA73 accumulate late in anther development and reach a maximum level in mature anthers prior to anthesis; BA54 has been confirmed to be pollen-specific. The third category, represented by BA42, is found to encode a protein sharing 64-67% amino acid similarity with chalcone synthase (CHS) from various plant species; the transcript is localized in the peripheral cells of the vascular bundle, tapetum, and developing microspores.

Acyltransferases↗
PubMed1995

In situ hybridization and immunohistochemistry of renal angiotensinogen in neonatal and adult rat kidneys.

Recent evidence suggests that a local renin-angiotensin system is operational in the kidney and that it mediates some of the actions of angiotensin II on renal tubules. In this study the ontogeny and renal distribution of the unique precursor to angiotensin II formation, angiotensinogen, was investigated in rats by use of immunohistochemistry, immuno-electron microscopy and non-isotopic hybridization histochemistry. At the light-microscopic level, intense staining for angiotensinogen was found in the proximal convoluted tubules of the cortex, with lighter staining in the straight proximal tubules of the outer stripe. The strongest immunostaining was found in the kidneys of neonatal rats, where glomerular mesangial cells and medullary vascular bundles were also immunopositive. The angiotensinogen content of the kidneys in late gestation embryos and neonates showed the presence of angiotensinogen by day E18 and a peak content in the neonate. Non-isotopic hybridization histochemistry with biotinylated oligodeoxynucleotide probes confirmed the presence of angiotensinogen mRNA expression in the proximal convoluted tubules of the renal cortex. Electron-microscopic immunohistochemistry showed staining of relatively few electron-dense structures close to the apical membrane of proximal convoluted tubule cells in the adult kidney. In the neonatal rat kidney, angiotensinogen immunostaining at the electron-microscopic level was found throughout the proximal tubule cells and was markedly stronger than that seen in adult kidney. The presence of angiotensinogen, from embryonic day 18, in the proximal tubules, mesangial cells and vasculature of the kidney suggests multiple potential sites of intrarenal angiotensin II generation with an ontogeny in late gestation.

Aging↗
PubMed1981

Renal function and concentrating ability in a desert rodent: the gundi (Ctenodactylus vali).

Clearance and cortical micropuncture experiments were carried out on non diuretic gundis. In this species, the kidney has a long and well developed papilla but, unlike other desert rodents, the vascular organization of the outer medulla is very simple. After withdrawal of water supply for either 24 h or 3 days before the experiments, the urine osmolality was only 1,361 +/- 57, n = 9, before and 1,136 +/- 89 mosmol . kg-1 during anesthesia. The GFR per 100 g B.W.(0.450 ml . min-1) is lower than in the rat studied under similar conditions. With regard to electrolytes the tubular handling of Na, Ca, K and Mg is similar to that observed for another desert rodent, psammomys obesus. For P, massive reabsorption (more than 30% of the filtered load) takes place along the distal convoluted tubule. The relatively poor concentrating ability of the gundi's kidney is not due to a lack of medullary recycling of urea since a net addition of urea to short loops of Henle is observed in this species. Physiological and morphological observations concerning the gundi and other desert rodent species suggest that the vascular bundle development in the outer medulla might affect the renal response to water deprivation.

Animals↗
PubMed1978

The cytochemical localization of nucleotide pyrophosphatase activity in plant tissues using naphthyl esters of thymidine-5'-phosphate.

A cytochemical method for the localization of nucleotide pyrophosphatase activity in plants employing naphthol AS-BI thymidine 5'-monophosphate and alpha-naphthyl thymidine 5'-monophosphate as specific substrates is reported. Biochemical evidence for the validity of this method is presented and the synthesis of the naphthol AS-BI ester is described. The application of this cytochemical technique to shoots of Triticum sp. and roots of Vicia faba has shown nucleotide pyrophosphatase to be ubiquitous in its distribution in these organs and to occur in a structurally-bound form in the cytoplasm. The highest activity was detected in developing fibres adjacent to the leaf vascular bundles, in the coleoptile epidermal and hypodermal cells and in the coleoptile and leaf xylem.

Chemical Phenomena↗
PubMed1994

Upper tibial corticocancellous flap anatomy study (19.2.93).

A cortico-cancellous flap from the anterolateral aspect of the upper third of the tibia was presented. Sixty lower limbs of "fresh" cadavers were dissected. The vascular bundle includes the anterior tibial artery and its recurrent collateral branches and recurrent and musculoperiosteal arteries. The flap is harvested with the interosseous membrane and can be used either free or predicled. We used this flap for two patients suffering from pseudarthrosis. Long range clinical and radiological results are good.

Adult↗
PubMed1982

[Renal medullary circulation: morphological characteristics of vessels and their organization].

The blood vessels of the renal medulla have several particular features. The supplying vessels of the renal medulla are the efferent arterioles of the juxtamedullary glomeruli. Thus, the blood supply is entirely postglomerular. The distribution of the blood within the renal medulla is effected by the descending vasa recta. Descending and ascending vasa recta form the vascular bundles. Descending vasa recta leave the bundles at any level of the medulla to feed the adjacent capillaries; the longest descending vasa recta reach the papillary tip. The capillary plexus are differently developed. A dense capillary plexus is present only in the inner stripe of the outer medulla. In the inner medulla the capillary plexuses are poorly developed. At these sites ascending recta contribute to the capillarisation. The ascending vasa recta originate from capillaries at any level of the medulla and ascend without joining together towards the intrarenal veins at the cortico-medullary border. They are capillary vessels with wide lumina. Within the outer stripe of the outer medulla these vessels are very narrowly associated with the tubules; interstitial spaces are very poorly developed at this site. These relationships are interpreted as a possible weak point of the medullary circulation in pathological situations.

Animals↗
PubMed1995

Developmental and tissue-specific regulation of the gene for the wheat basic/leucine zipper protein HBP-1a(17) in transgenic Arabidopsis plants.

Wheat basic/leucine zipper protein HBP-1a(17) binds in vitro specifically to ACGT motif-containing cis-acting elements, such as the type I element of plant histone promoters and the G-box of hormone- and light-inducible promoters. To address the in vivo function of HBP-1a(17), we isolated and structurally analyzed the HBP-1a(17) gene and examined its expression in transgenic Arabidopsis plants. The HBP-1a(17) gene is composed of 14 exons; the basic region and leucine zipper are encoded by separate small exons, as is the case for other bZIP protein genes. The G-box of the HBP-1a(17) promoter bound specifically to HBP-1a(17) and its related HBP-1a isoforms, suggesting that the HBP-1a(17) gene may be autoregulated, although the binding affinity of these proteins in vitro is very low. In Arabidopsis plants, activation of the HBP-1a(17) promoter was highly restricted to photosynthetically active mesophyll, and guard cells and vascular bundles of vegetative leaves. Etiolation of transgenic plants resulted in inhibition of expression of the HBP-1a(17) promoter. Indeed, the HBP-1a(17) promoter contains several sequence elements homologous to cis-acting elements conserved in light-inducible promoters. It is, therefore, assumed that the HBP-1a(17) gene is light regulated and that HBP-1a(17) is involved in light-responsive gene transcription via the G-box.

Amino Acid Sequence↗
PubMed1991

Effect of varying salt and urea permeabilities along descending limbs of Henle in a model of the renal medullary urine concentrating mechanism.

Modelling studies have played an important role in research on the mechanism of urine concentration and dilution by the medulla of the kidney ever since Hargitay and Kuhn (1951, Z. Elektrochem. 55, 539-558) first proposed that the parallel tubular structures in the kidney medulla must function as a "countercurrent multiplication" system. Present-day models, in keeping with our considerably improved understanding of most aspects of medullary structure-function relationships, have evolved into rather sophisticated systems of parallel tubes. In spite of this increasing complexity, it has remained the case that "model medullas" do not concentrate as well as the real kidney, especially in the inner medulla where only passive, diffusional transport occurs. Inasmuch as these models take into account the majority of contemporary ideas making up our global hypothesis about the functioning of this system, their failure to behave physiologically indicates that our understanding remains incomplete. The purpose of the present modelling study was to evaluate the implications of some recent measurements showing that permeabilities of NaCl (Ps) and urea (Pu) vary along the length of the descending thin limbs of Henle (Imai et al., 1988, Am. J. Physiol. 254, F323-F328), rather than being constant throughout this segment as had been assumed earlier. It was hoped that these newly measured values might explain, by a passive, diffusional process, the net solute addition at the bend of Henle's loop observed under some circumstances and heretofore attributed (though without any supporting experimental evidence) to active transport into the descending limb. The results of the present study show that whereas incorporation of the new values for Ps and Pu in the descending limbs of short nephrons does indeed improve the concentrating power of the model, these new values are nonetheless not sufficient to allow the model to build an osmolarity gradient that increases all the way through the inner medulla. This failing, which is common to virtually all modelling studies to date using measured values from rat kidneys, probably points to a key role for preferential exchange supposed by some to exist among certain tubule segments within vascular bundles in species whose kidneys have the highest concentrating power.

Animals↗
PubMed1992

Ureteral incarceration in the symptomatology of hydronephrosis.

Renal colic symptoms may be caused by an aberrant vascular bundle that intermittently incarcerates the pyeloureteral junction. The authors describe 6 patients who were complaint free except for the period of fits and routine urological examinations showed normal findings. The patients had no subjective complaints after open surgery.

Adult↗
PubMed1993

Autoradiographic localization of prazosin and rauwolscine binding sites in the human kidney.

In the human kidney, binding sites for the alpha 1-adrenoceptor antagonist 3H-prazosin and the alpha 2-adrenoceptor antagonist 3H-rauwolscine were localized and quantified by in vitro autoradiography. 3H-prazosin binding was found predominantly in the renal cortex. In the medulla, tubular structures were also specifically labelled. No binding sites, however, were detected in association with glomeruli or large blood vessels. 3H-rauwolscine labelled the medullary vascular bundles intensively, but no binding sites were associated with glomeruli or other cortical structures. Thus, the binding pattern for 3H-prazosin is quite similar in both human and rat renal cortex. There are, however, distinct differences between human and rat kidneys in the distribution of the alpha 2-adrenergic binding sites visualized with the antagonist 3H-rauwolscine.

Animals↗