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PubMed1993

Experimental femoral vein reconstruction with expanded polytetrafluoroethylene grafts seeded with endothelial cells.

The effect of endothelial cell seeding on the patency of small-caliber expanded polytetrafluoroethylene (ePTFE) grafts used for venous replacements in a canine experimental model was evaluated. Grafts were implanted bilaterally in 12 dogs as femoral vein interpositions. In each animal, one graft was seeded with enzymatically derived homologous endothelial cells which had been cultivated for 3 days in vitro before implantation, whereas the contralateral graft was not seeded. In five dogs, venography was performed at 2 weeks, and grafts were then excised. In the remaining seven dogs, venography was performed at both 2 and 4 weeks, with graft excision at 4 weeks. Graft patency at 2 weeks for seeded grafts was 75% (nine of 12) compared with only 33% (four of 12) for unseeded grafts (P < 0.02). There were no new episodes of thrombotic occlusion between 2 and 4 weeks. Five dogs with thrombus in the control graft did not develop thrombus in the contralateral seeded graft. Furthermore, each dog with a patent control graft had no thrombus in the seeded graft. It is concluded that the early patency of seeded ePTFE grafts is superior to that of unseeded ePTFE grafts in the femoral vein.

Animals↗

PubMed1982

Isolation and characterization of a Lewis b-active lectin from Griffonia simplicifolia seeds.

A fourth lectin (GS IV), a serologically Lewis b (Leb)-active binding lectin, was isolated from Griffonia simplicifolia seeds by affinity chromatography on an Leb (alpha-L-fucose-(1 leads to 2)-beta-D-Gal-(1 leads to 3)-[alpha-L-fucose-(1 leads to 4)]-beta-D-GlcNAc)-active fragment coupled to Synsorb, followed by elution with 0.1 N acetic acid. The purified lectin was shown to be homogeneous by polyacrylamide gel electrophoresis and analytical gel column chromatography on Sephadex G-200. A glycoprotein containing mannose, N-acetylglucosamine, fucose, and xylose (4:2:1:1), the lectin is a dimer composed of subunits of Mr = 29,000 and 27,000 with an aggregate Mr = 56,000. The GS IV lectin precipitate equally with blood group Leb fragment-bovine serum albumin (BSA) and H-active fragment (alpha-L-fucose-(1 leads to 2)-beta-D-Gal-(1 leads to 4)-[alpha-L-fucose-(1 leads to 3)]-beta-D-GlcNAc)-BSA conjugates but only poorly with a Lewis a fragment-BSA conjugate. Inhibition of precipitation with various mono- and oligosaccharides indicated that the lectin is specific for type 1 or 2 chains containing two alpha-L-fucosyl groups on C-2 of the D-galactosyl residue and C-3 or C-4 of the D-GlcNAc unit. One alpha-L-fucosyl residue on C-3 or C-4 of the D-GlcNAc residue of type 1 or 2 chains inhibited the reaction, although these oligosaccharides were less active than the oligosaccharides containing 2 alpha-L-fucosyl units. L-Fucose, methyl alpha- or beta-fucoside, and p-nitrophenyl alpha- or beta-L-fucoside did not inhibit the lectin. GSIV did not display mitogenic activity against mouse spleen cells or human peripheral lymphocytes.

Amino Acids↗

PubMed1998

Newly recruited and pre-existing preadipocytes in cultures of porcine stromal-vascular cells: morphology, expression of extracellular matrix components, and lipid accretion.

Expression of extracellular matrix (ECM) components during differentiation of pre-existing preadipocytes and preadipocytes recruited by dexamethasone (DEX) was examined with immunocytochemistry in primary cultures of adipose tissue stromal vascular (S-V) cells. Immunocytochemistry showed that a small proportion of preadipocytes (AD-3+) in 24-h cultures (d 0 to 1) contained lipid or expressed ECM. Two days of insulin treatment markedly increased preadipocyte ECM expression, and preadipocytes were "rounder" than those not treated with insulin. Dexamethasone with insulin increased preadipocyte recruitment two- to fivefold in completely serum-free cultures and in cultures serum-free after seeding and plating in serum for 1 to 3 d. Double staining demonstrated that ECM expression and lipid accretion were tightly coupled and lagged significantly behind preadipocyte recruitment (AD-3 expression). Double staining (lipid and AD-3) also demonstrated remarkable and unexpected cytological traits indicating a "reticuloendothelial" nature of newly recruited preadipocytes. Time-lapse phase contrast microscopy verified these observations and demonstrated that small adipocytes and preadipocytes migrated and formed cell-to-cell contacts while aggregating and clustering. Large clusters of lipid-free preadipocytes developed in DEX-treated cultures, but not in cultures treated with DEX + insulin. However, the influence of DEX on preadipocyte recruitment and ECM expression was independent of insulin. Preadipocytes on ECM substrata accumulated lipid but were "flat" and did not express ECM components, regardless of insulin or DEX treatment. These studies clearly indicate that preadipocytes express ECM components after recruitment, and the ECM may be critical for morphological development of adipocytes.

Adipocytes↗

PubMed2003

pH-dependent aggregation of oligomeric Artocarpus hirsuta lectin on thermal denaturation.

The pH dependence of the activity, aggregation, and secondary structure of Artocarpus hirsuta lectin was studied using intrinsic and extrinsic fluorescence, light scattering, and circular dichroism. The lectin is more stable in the neutral and acidic than in the alkaline pH range, which is also reflected in the binding constants of the lectin to methyl alpha-galactopyranoside (me alpha-gal). The aggregation of the protein due to heat denaturation is prevented at both extremes of pH. The binding of hydrophobic dye to the lectin takes place at pH 1-2, which increases with increasing temperature. The exposure of hydrophobic patches at pH 1 is reversible. The secondary structure of the lectin is intact in the pH range of 1-8 and is distorted above pH 9. Aggregation of the protein due to heat denaturation is also prevented in the presence of guanidine hydrochloride (GdnHCl).

Artocarpus↗

PubMed1993

Interactions of elastin and microfibrils in elastogenesis of human pulmonary fibroblasts in culture.

The interaction of elastin and microfibrils in elastogenesis in vitro was investigated with electron microscopy and immunohistochemistry. Fetal human pulmonary fibroblasts were cultured with or without beta-aminopropionitrile (BAPN). One week after seeding, the extracellular microfibrils were loosely arranged without elastin deposition. Two and six week culture in controls, mature elastic fibers and microfibril bundles were formed. In cultures with BAPN, the microfibrils were loosely arranged, and a few microfibril bundles and no amorphous components were formed. Immunoelectron microscopy for elastin showed the reaction at the outer zones of amorphous components in controls, though the loosely-arranged microfibrils reacted diffusely in cultures with BAPN. Six week culture with BAPN, aggregated masses of elastin, which were dissociated from microfibrils, were found. In conclusion, deposition and maturation of elastin on microfibrils are necessary to form the microfibril bundles in normal elastogenesis, and vaguely outlined aggregated masses of elastin are formed under the inhibition of lysyl oxidase.

Aminopropionitrile↗

PubMed2005

Template-directed self-assembly and growth of insulin amyloid fibrils.

The formation of amyloid aggregates in tissue is a pathological feature of many neurodegenerative diseases and type II diabetes. Amyloid deposition, the process of amyloid growth by the association of individual soluble amyloid molecules with a pre-existing amyloid template (i.e., plaque), is known to be critical for amyloid formation in vivo. The requirement for a natural amyloid template, however, has made amyloid deposition study difficult and cumbersome. In the present work, we developed a novel, synthetic amyloid template by attaching amyloid seeds covalently onto an N-hydroxysuccinimide-activated surface, where insulin was chosen as a model amyloidogenic protein. According to ex situ atomic force microscopy observations, insulin monomers in solution were deposited onto the synthetic amyloid template to form fibrils, like hair growth. The fibril formation on the template occurred without lag time, and its rate was highly accelerated than in the solution. The fibrils were long, over 2 mum, and much thinner than those in the solution, which was caused by limited nucleation sites on the template surface and lack of lateral twisting between fibrils. According to our investigations using thioflavin T-induced fluorescence, birefringent Congo red binding, and circular dichroism, fibrils grown on the template were identified to be amyloids that formed through a conformational rearrangement of insulin monomers upon interaction with the template. The amyloid deposition rate followed saturation kinetics with respect to insulin concentration in the solution. The characteristics of amyloid deposition on the synthetic template were in agreement with previous studies performed with human amyloid plaques. It is demonstrated that the synthetic amyloid template can be used for the screening of inhibitors on amyloid deposition in vitro.

Adsorption↗

PubMed2003

Gland cell cultures into 3D hyaluronan-based scaffolds.

In this study we report a preliminary investigation of the feasibility of non-woven/sponge fabrics of a hyaluronan derived biomaterials (benzyl ester of HA (HYAFF-11 FAB, Abano Terme, Italy) for the in vitro culture of rat hepatocytes and rat beta cells. Cell growth on hyaluronan derived biomaterials were tested in the presence of complete medium and in the presence of ECM (extracellular matrix) secreted by fibroblasts previously cultured into the scaffold. Hepatocytes and beta cells were extracted from rat liver/pancreas and seeded either on the HYAFF-11 scaffold alone, or on HYAFF-11 scaffold containing ECM. Direct assay of cell proliferation was performed with MTT test. For morphological observations samples were stained with hematoxylin and eosin. The results obtained by MTT test showed that hepatocytes cultivated in both the above described conditions were able to proliferate up to 14 days and Langerhans islet up to 21 days. After this time, cells started to undergo apoptosis. The morphological analyses showed cell aggregation in three-dimensional structures promoted by the fibers of the biomaterial. Our results confirmed that HYAFF-11 meshes represent a suitable scaffold for hepatocyte adhesion/Langerhans islet organization and proliferation. In particular, the presence of a fibroblast secreted extracellular matrix improves the biological property of the scaffold.

Journal Article↗

PubMed2000

Rhizosphere soil aggregation and plant growth promotion of sunflowers by an exopolysaccharide-producing Rhizobium sp. strain isolated from sunflower roots.

Root-adhering soil (RAS) forms the immediate environment where plants take up water and nutrients for their growth. We report the effect of an exopolysaccharide (EPS)-producing rhizobacterium (strain YAS34) on the physical properties of sunflower (Helianthus annuus L.) RAS, associated with plant growth promotion, under both water stress and normal water supply conditions. Strain YAS34 was isolated as a major EPS-producing bacterium from the rhizoplane of sunflowers grown in a French dystric cambisol. Strain YAS34 was assigned to the Rhizobium genus by 16S ribosomal DNA gene sequencing. Inoculation of sunflower seeds and soil with strain YAS34 caused a significant increase in RAS per root dry mass (dm) (up to 100%) and a significant increase in soil macropore volume (12 to 60 microm in diameter). The effect of inoculation on sunflower shoot dm (up to +50%) and root dm (up to +70%) was significant under both normal and water stress conditions. Inoculation with strain YAS34 modified soil structure around the root system, counteracting the negative effect of water deficit on growth. Using [(15)N]nitrate, we showed that inoculation made the use of fertilizer more effective by increasing nitrogen uptake by sunflower plantlets.

Helianthus↗

PubMed1980

Some studies on the composition and surface properties of oil bodies from the seed cotyledons of safflower (Carthamus tinctorius) and linseed (Linum ustatissimum).

1. The average oil-body diameter in intact cells of developing linseed (Linum usitatissimum) and safflower (Carthamus tinctorius) cotyledons was similar (about 1.4 micrometer), and there was little change in size after oil bodies were isolated and repeatedly washed. 2. The glycerolipid composition of washed oil bodies from both developing and mature cotyledons of the two species was similar; oil bodies from ten different batches of cotyledons contained 4.3 +/- 0.16 mumol of 3-sn-phosphatidylcholine and 25.2 +/- 1.7 mumol of diacylglycerol per 1000 mumol of triacylglycerol. During four successive washings of a once-washed oil-body preparation, the proportion of diacylglycerol to triacylglycerol remained constant and that of 3-sn-phosphatidylcholine to triacylglycerol decreased by only 20%. 3. The protein content of thrice-washed oil bodies from the two species was similar, about 2.4% of the weight of glycerolipids, and appeared to be independent of the stage of cotyledon maturity. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated that the protein of purified oil bodies from the two species consisted mainly of only four polypeptides and that two of the polypeptides from each species had apparent mol.wts. of 17500 and 15500. Similar patterns of polypeptides were obtained after the hydrolysis of the 15500-mol.wt. polypeptides from linseed and safflower oil bodies by Staphylococcus aureus V8 proteinase, whereas the proteolysis of the 17500-mol.wt. polypeptides from the two species produced different patterns of polypeptides. 4. The 3-sn-phosphatidylcholine in oil-body preparations was hydrolysed about 85% by bee-venom phospholipase A2 without any apparent coalescence of the oil bodies. Incubation with lipase from Rhizopus arrhizus caused rapid coalescence of the oil bodies, and this lipase appeared to initially hydrolyse diacylglycerols in preference to triacylglycerol. 5. Oil bodies from both species were almost completely dispersed in suspensions of pH between 7.1 and 8.3, but formed large aggregates at pH values between 6.7 and 3.9; pH-induced aggregation caused no coalescence. Aggregates formed under acidic conditions were dispersed by re-adjusting the pH of suspensions to 8.3. 6. A freeze-etch electron-microscopic examination of isolated oil bodies indicated that these organelles were bounded by some form of membrane with a particle-free outer surface.

Chemical Phenomena↗

PubMed2003

Culture of hepatocytes on fructose-modified chitosan scaffolds.

Fructose was conjugated onto the inner surface of highly porous chitosan scaffold prepared by lyophilization. The modified scaffold with average pore size 50-200 microm was used to cultivate rat hepatocytes harvested by portal vein collagenase perfusion. The results indicated that while chitosan sponge alone supported cell attachment and growth, the scaffold modified with fructose accommodated a much larger number of hepatocytes due to the specific interaction between seeded hepatocytes and fructose moieties conjugated onto the surface of the scaffold. Hepatocytes exhibited a round cellular morphology with many microvilli evident on the surface of the cells, indicating healthy cells. Metabolic activities in terms of albumin secretion and urea synthesis were evaluated. It was found that hepatocytes cultured within fructose-modified scaffold resulted in much higher activities than within unmodified chitosan sponge. Scanning electron microscopy results showed that fructose-modified porous scaffold promoted the formation of cellular aggregates.

Albumins↗

PubMed2006

Crystallization and preliminary characterization of a highly thermostable lectin from Trichosanthes dioica and comparison with other Trichosanthes lectins.

A lectin from Trichosanthes dioica seeds has been purified and crystallized using 25%(w/v) PEG 2K MME, 0.2 M ammonium acetate, 0.1 M Tris-HCl pH 8.5 and 50 microl 0.5%(w/v) n-octyl beta-D-glucopyranoside as thick needles belonging to hexagonal space group P6(4). Unit-cell parameters were a = b = 167.54, c = 77.42 A. The crystals diffracted to a Bragg spacing of 2.8 A. Both the structures of abrin-a and T. kirilowii lectin could be used as a model in structure determination using the molecular-replacement method; however, T. kirilowii lectin coordinates gave better values of reliability and correlation parameters. The thermal, chemical and pH stability of this lectin have also been studied. When heated, its haemagglutination activity remained unaffected up to 363 K. Other stability studies show that 4 M guanidinium hydrochloride (Gdn-HCl) initiates unfolding and that the protein is completely unfolded at 6 M Gdn-HCl. Treatment with urea resulted in a total loss of activity at higher concentrations of denaturant with no major structural changes. The protein remained stable over a wide pH range, from pH 6 to pH 12, except for partial unfolding at extremely alkaline pH. The role of disulfide bonds in the protein stability was found to be insignificant. Rayleigh light-scattering studies showed no molecular aggregation in any of the extreme treated conditions. The unusual stability of this lectin resembles that of type II ribosome-inactivating proteins (type II RIPs), which is also supported by structure determination. The structural features observed in a preliminary electron-density map were compared with the other two available Trichosanthes lectin structures.

Crystallization↗

PubMed2002

Modulation of human endothelial cell behaviour in simulated microgravity.

Eukaryotic organisms are influenced by gravitational forces in their environment. The low gravitational forces endured by organisms in space alter cellular processes in cultured mammalian cells. Endothelial cells represent an interesting model to study because of their crucial role in the pathogenesis of various diseases, from atherosclerosis to inflammation to any situation characterized by dysregulated angiogenesis. We therefore cultured human endothelial cells derived from the umbilical vein in Rotating Wall Vessels (RWV) that simulate microgravity on earth. Under these experimental conditions, cells are viable and no increase in apoptotic rate was observed. They grow reproducibly faster than controls up to 8 days from seeding. Because endothelial proliferation is crucial in angiogenesis, we evaluated other steps required for new blood vessels to form. We found no variations in the levels of metalloproteases and an increased synthesis of their inhibitors (TIMP), suggesting that hypogravity does not induce a pro-angiogenic phenotype. Since i) alterations of blood pressure have been observed in astronauts and ii) endothelial cell synthesize vasoactive molecules, we evaluated the synthesis of nitric oxide and prostacyclin, both potent vasodilators and inhibitors of platelet aggregation. We observed that human endothelial cells grown in hypogavity synthesize higher amounts of prostacyclin and nitric oxide than controls. More studies are ongoing to understand the molecular basis of these events and their role in altering the physiology of the vascular tree.

Journal Article↗

PubMed1978

[Factors which influence the size of calcium oxalat crystals during their formation from saturated solutions].

The nucleation and growth of Ca-oxalate crystals from metastable and instable solutions was studied in some detail to find out the dependence of the crystal size on the absolute calcium resp. oxalate concentration, further on their molar ratio, on the presence resp. absence of crystal seeds, on the agitation resp. stagnation of the Ca-oxalate solution, on the duration of crystallization and on the renewing of the Ca-oxalate containing supernatant, thus simulating a prolonged (dietary) oxalate load in vivo. The most important findings are the clear inhibition of crystal growth at higher and very high calcium concentrations (in contrary to the unhindered crystal enlargement at high oxalate concentrations), further the eminent role of the oxalate in the formation of big crystals and crystal aggregates, as well as the substantial crystal enlargement at the persistent oxalate load.

Calcium Oxalate↗

PubMedDate not supplied

Induction of vascular endothelial phenotype and cellular proliferation from human cord blood stem cells cultured in simulated microgravity.

Recent studies have demonstrated that stem cells derived from adult hematopoietic tissues are capable of trans-differentiation into non-hematopoietic cells, and that the culture in microgravity (microg) may modulate the proliferation and differentiation. We investigated the application of microg to human umbilical cord blood stem cells (CBSC) in the induction of vascular endothelial phenotype expression and cellular proliferation. CD34+ mononuclear cells were isolated from waste human umbilical cord blood samples and cultured in simulated microg for 14 days. The cells were seeded in rotary wall vessels (RWV) with or without microcarrier beads (MCB) and vascular endothelial growth factor was added during culture. Controls consisted of culture in 1 G. The cell cultures in RWV were examined by inverted microscopy. Cell counts, endothelial cell and leukocyte markers performed by flow cytometry and FACS scan were assayed at days 1, 4, 7 and at the termination of the experiments. Culture in RWV revealed significantly increased cellular proliferation with three-dimensional (3D) tissue-like aggregates. At day 4, CD34+ cells cultured in RWV bioreactor without MCB developed vascular tubular assemblies and exhibited endothelial phenotypic markers. These data suggest that CD34+ human umbilical cord blood progenitors are capable of trans-differentiation into vascular endothelial cell phenotype and assemble into 3D tissue structures. Culture of CBSC in simulated microg may be potentially beneficial in the fields of stem cell biology and somatic cell therapy.

Antigens, CD34↗

PubMed2003

Preparation of nearly monodisperse multiply coated submicrospheres with a high refractive index.

Nearly monodisperse SiO2/TiO2/SiO2 multiply coated submicrospheres with nearly monodisperse silica submicrospheres as cores, thick titania layers, and thin silica skin were prepared to increase the refractive index of complex submicrospheres while keeping their near monodispersity and perfect surface properties. Nearly monodisperse colloidal silica submicrospheres as cores with a diameter of 200 nm were synthesized by a seeding technique on the basis of the hydrolysis of tetraethyl orthosilicate (TEOS) in an aqueous ethanol solution with ammonia as catalyst. On the basis of the hydrolysis of tetrabutyl orthotitanate, a procedure combining continuous feeding with multistep coating was determined to prepare titania coatings about 40 nm thick and increase the refractive index of the complex submicrospheres. The hydrolysis of TEOS was still used to get the outmost silica coating about 10 nm thick on titania coated silica submicrospheres to eliminate random aggregation caused by the TiO2 surface properties of the TiO2/SiO2 complex submicrospheres during the final fabrication of photonic crystals.

Journal Article↗

PubMed2002

TNFalpha-induced apoptosis and integrin switching in human extravillous trophoblast cell line.

Differentiation of extravillous trophoblast cells (EVT) to an invasive phenotype plays an essential role in establishing and maintaining feto-placental organization during human pregnancy. A switch in integrin expression occurs during this differentiation and is accompanied by changes in the extracellular matrix (ECM). Alteration of EVT behavior is also modulated by cytokines. To investigate the molecular interactions involved in the EVT differentiation, we examined the effects of cytokines and ECM on the human EVT cell line, TCL1 cells. We found that tumor necrosis factor alpha (TNFalpha) induced apoptosis in TCL1 cells but not in JEG3 cells derived from choriocarcinoma while the addition of interleukin-1beta, leukemia inhibitory factor, or transforming growth factor had no effect on TCL1 cells. This apoptosis was suppressed when TCL1 cells were seeded on fibronectin (Fn), collagen type I (C1), collagen type IV (C4), or laminin (Ln). Wortmannin, a specific PI3 kinase inhibitor, inhibited this suppression. Spreading assays and adhesion blocking assays indicated that TCL1 cells express integrin-alpha5 and -alpha6 and beta1 and beta4 subunits. Adhesion on Fn is mediated by alpha5beta1, and adhesion on C1, C4, or Ln is mediated by alpha6beta1 integrins. TNFalpha suppressed alpha6 integrin expression and enhanced alpha1 integrin expression in a dose-dependent manner. In addition, aggregation of beta1 subunits on C4 was detected after addition of TNFalpha. Taken together, these results suggest that TNFalpha and ECM, through activation of PI3 kinase mediated by beta1 integrin signaling, might collaboratively regulate differentiation of trophoblast cells through integrin signaling in establishing and maintaining successful pregnancy.

Apoptosis↗

PubMed1996

Intramolecular disulfide bonds between conserved cysteines in wheat gliadins control their deposition into protein bodies.

Following synthesis, wheat gliadin storage proteins are deposited into protein bodies inside the endomembrane system in a way that enables not only their efficient accumulation and dehydration during seed maturation, but also their rapid rehydration and degradation during germination. In the present report, we studied the mechanism of gliadin deposition and whether it was controlled by the conformation of these proteins. Although gliadins are generally known to be insoluble in aqueous solutions, sucrose gradient analysis showed that a considerable amount of these proteins appeared as relatively soluble monomers in developing grains. In vitro reduction of the intramolecular disulfide bonds that are present in natural monomeric gliadins caused their precipitation into insoluble aggregates. In addition, pulse-chase experiments in the absence or presence of reducing agents showed that formation of intramolecular disulfide bonds also played a major role in folding and deposition of the gliadins in vivo. Our results imply that following sequestration into the endoplasmic reticulum, the gliadins fold into relatively soluble monomers, which are incompetent for rapid aggregation and gradually assemble into protein bodies. This pattern of deposition apparently depends on the conformation of the gliadins, which is stabilized by intramolecular disulfide bonds formed between the conserved cysteines. The contribution of this study to the understanding of the evolution and function of gliadins is discussed.

Amino Acid Sequence↗

PubMed2005

Distribution of fertility-restorer genes for wild-abortive and Honglian CMS lines of rice in the AA genome species of genus Oryza.

BACKGROUND AND AIMS: Rice (Oryza sativa) is one of the most important cereal plants in the world. Wild-abortive (WA) and Honglian (HL) cytoplasmic male sterility (CMS) have been used extensively in the production of hybrid seeds. Although a variable number of fertility-restorer genes (Rf) for WA and HL-CMS have been identified in various cultivars, information on Rf in Oryza species with the AA-genome is sparse. Therefore the distribution and heredity of Rf for WA and HL-CMS in wild rice species of Oryza with the AA-genome were investigated. METHODS: Fertility-restorer genes for WA and HL-CMS in wild rice species with the AA-genome were investigated by following the fertility of microspores identified by I2-KI staining and by following the seed-setting rate of spikelets. A genetic model of Rf in some selected restorer accessions was analysed based on the fertility segregation of BC1F1 populations. KEY RESULTS: Fertility analysis showed that 21 out of 35 HL-type F1s, and 13 out of 31 WA-type F1s were scored as fertile. The frequency of Rf in wild rice was 60% for HL-CMS and 41.9% for WA-CMS, respectively. The fertility-restorer accessions, especially those with complete restoring ability, aggregated mainly in two species of O. rufipogon and O. nivara. The wild rice accessions with Rf for HL-CMS were distributed in Asia, Oceania, Latin American and Africa, but were centered mainly in Asia, whilst the wild restorer accessions for WA-CMS were limited only to Asia and Africa. Apart from one restorer accession that possessed two pairs of Rf for WA-CMS, all of the other nine tested wild restorer accessions each contained only a single Rf for WA-CMS or HL-CMS. Allele analysis indicated that there existed at least three Rf loci for the WA and HL-CMS systems. CONCLUSIONS: These data support the hypothesis that fertility-restorer genes exist widely in Oryza species with the AA-genome, and that Rf in Oryza sativa originated from the Oryza rufipogon/Oryza nivara complex, the ancestor of cultivated rice in Asia. The origin and evolution of Rf is tightly linked to that of CMS in wild rice, and fertility of a given CMS type is controlled by several Rf alleles in various wild restorer accessions.

Alleles↗