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PubMed1986

Characterization of alcohol dehydrogenase in young soybean seedlings.

Molecular properties of alcohol dehydrogenase (ADH) were examined in young soybean seedlings. Soybean radicle tissue is ADH-rich. Enzyme specific activity decreases slowly with the development of roots and becomes almost undetectable when the first true leaves appear. Soybean ADH was not found to be inducible by flooding. 2,4-Dichlorophenoxyacetic acid (2,4-D) treatment increased ADH specific activity as much as 14-fold. Only one ADH isozyme was detected by isoelectric focusing. By DNA-DNA hydridization, soybean ADH genomic sequences were shown to be partly homologous to maize ADH1 cDNA. The presence of more than one Adh gene in soybean is discussed.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2004

High-frequency plant regeneration through callus initiation from mature embryos of maize ( Zea Mays L.).

An efficient maize regeneration system was developed using mature embryos. Embryos were removed from surface-sterilized mature seeds and sliced into halves. They were used as explants to initiate callus on induction medium supplemented with 4.0 mg l(-1) 2,4-dichlorophenoxyacetic acid (2,4-D). The induction frequency of primary calli was over 90% for all inbred lines tested. The primary calli were then transferred onto subculture medium supplemented with 2.0 mg l(-1) 2,4-D. Following two biweekly subcultures, embryogenic calli were formed. Inclusion of a low concentration (0.2 mg l(-1)) of 6-benzylaminopurine (BA) in the subculture medium significantly promoted the formation of embryogenic callus. The addition of silver nitrate (10 mg l(-1)) also supported an increased frequency of embryogenesis. The embryogenic callus readily formed plantlets on regeneration medium supplemented with 0.5 mg l(-1) BA. The regenerated plantlets were transferred to half-strength Murashige and Skoog medium supplemented with 0.6 mg l(-1) indole-3-butyric acid to develop healthy roots. The regenerated plantlets were successful on transfer to soil and set seed. Using this system, plantlets were regenerated from seven elite maize inbred lines. The frequency of forming green shoots ranged from 19.8% to 32.4%. This efficient regeneration system provides a solid basis for genetic transformation of maize.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2004

Control of development and valepotriate production by auxins in micropropagated Valeriana glechomifolia.

Valeriana glechomifolia is a plant species endemic to southern Brazil that accumulates valepotriates, which are terpene derivatives, in all of its organs. Valepotriates are the presumed sedative generic components of the pharmaceutically used species of Valeriana. The influence of various concentrations of the auxins indole-3-acetic acid, indole-3-butyric acid and alpha-naphthaleneacetic acid on the growth of micropropagated V. glechomifolia was investigated under conditions of transient and continuous exposure. Changes in the development of roots and shoots as well as the production of the valepotriates acevaltrate, valtrate and didrovaltrate (analyzed by high-performance liquid chromatography) were evaluated. The best performance in valepotriate production, growth and survival under ex vitro conditions following plant acclimatization was achieved in the continuous presence of 5.71 microM IAA. When cultured in medium containing IAA plants produced stable levels of valepotriates throughout the entire cultivation period.

Acclimatization↗
PubMed2025

Replacement of chromosome 3D with Thinopyrum chromosome 3St led to increased drought tolerance during the flowering stage in wheat.

The stable 3St(3D) substitution line offers promising genetic potential for improving drought tolerance in wheat during critical reproductive stages. The flowering stage is highly susceptible to drought, which significantly reduces wheat grain yield globally. Low genetic diversity in wheat further limits the discovery of optimal gene variants for breeding climate-resilient varieties. The substitution of chromosome 3D by a group 3 chromosome pair from Thinopyrum intermedium × Th. ponticum artificial hybrid was identified using in situ hybridization and genotyping-by-sequencing. This homoeologous substitution showed good functional compensation for grain yield and fertility, similar to the wheat parents ('Mv9kr1' and 'Mv Karizma') in field and greenhouse trials. The substitution line exhibits a semidwarf phenotype due to the Rht8 and Rht2 dwarfing alleles. Automated shoot phenotyping after a 10-day water withdrawal at flowering revealed efficient water preservation allowing to maintain photosynthetic functions, sustained photosynthetic activity, and less chlorophyll degradation, indicated by Normalized Difference Vegetation Index (NDVI) and modified Normalized Difference Index (mND705) values and moderate level of protective functions shown by the expression of stress-related genes. Compared to the wheat parents, the substitution line developed thicker roots with increased volume under drought, resulting in a lower surface-to-volume ratio. This may enhance water storage efficiency and help reduce yield loss under drought conditions.

Triticum↗
PubMed2004

Dormancy of Arabidopsis seeds and barley grains can be broken by nitric oxide.

Seeds of Arabidopsis thaliana (L.) Heynh. and grains of barley ( Hordeum vulgare L.) were used to characterize the affects of nitric oxide (NO) on seed dormancy. Seeds of the C24 and Col-1 ecotypes of Arabidopsis are almost completely dormant when freshly harvested, but dormancy was broken by stratification for 3 days at 4 degrees C or by imbibition of seeds with the NO donor sodium nitroprusside (SNP). This effect of SNP on dormancy of Arabidopsis seeds was concentration dependent. SNP concentrations as low as 25 microM reduced dormancy and stimulated germination, but SNP at 250 microM or more impaired seedling development, including root growth, and inhibited germination. Dormancy was also reduced when Arabidopsis seeds were exposed to gases that are generated by solutions of SNP. Nitrate and nitrite, two other oxides of nitrogen, reduced the dormancy of Arabidopsis seeds, but much higher concentrations of these were required compared to SNP. Furthermore, the kinetics of germination were slower for seeds imbibed with either nitrate or nitrite than for seeds imbibed with SNP. Although seeds imbibed with SNP had reduced dormancy, seeds imbibed with SNP and abscisic acid (ABA) remained strongly dormant. This may indicate that the effects of ABA action on germination are downstream of NO action. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3 oxide (cPTIO) strengthened dormancy of unstratified and briefly stratified Arabidopsis seeds. Dormancy of three cultivars of barley was also reduced by SNP. Furthermore, dormancy in barley grain was strengthened by imbibition of grain with cPTIO. The data presented here support the conclusion that NO is a potent dormancy breaking agent for seeds and grains. Experiments with the NO scavenger suggest that NO is an endogenous regulator of seed dormancy.

Arabidopsis↗
PubMed2000

Expression pattern of (+)-delta-cadinene synthase genes and biosynthesis of sesquiterpene aldehydes in plants of Gossypium arboreum L.

The cotton (+)-delta-cadinene synthase, a sesquiterpene cyclase, is encoded by a complex gene family which, based on homology, can be divided into two subfamilies: cad1-A and cad1-C. Southern blots revealed several members of the cad1-C subfamily, and a single member of the cad1-A subfamily, in the diploid Gossypium arboreum genome. One of the cad1-C genes, cad1-C3, was isolated from this species. According to reverse transcriptase-polymerase chain reaction, transcripts of both cad1-C and cad1-A genes appeared in roots from the second day post germination and in 1-d-old cotyledons, whereas the transcription levels were too low to be detected in the hypocotyls. Initially, sesquiterpene cyclase activities were found to be high in the seedlings, then dropped in aerial organs but increased in roots during development. Sesquiterpene aldehyde contents followed the same pattern. In fully developed plants, the transcripts of cad1-C were detected in stems, leaves and pericarps, as well as in the sepals and petals 3 d before anthesis, but not at the day of anthesis. In contrast, cad1-A transcripts were not detected in any of these aerial organs. The sesquiterpene aldehyde contents increased in petals but decreased in sepals after anthesis. Treatment of G. arboreum stems with a Verticillium dahliae elicitor-preparation activated cad1-A transcription, but a significant level of cad1-C transcripts was detected both before and after elicitation. In G. hirsutum cv. GL-5, a glandless cultivar, the cad1-C gene was activated by the same fungal elicitor, followed by the synthesis of the sesquiterpene cyclase, and accumulation of sesquiterpene aldehydes. The cad1 gene expression during development and in response to elicitation, as well as the spatial and temporal pattern of sesquiterpene biosynthesis, constitute a chemical defense machinery in cotton plants.

Blotting, Southern↗
PubMed2004

Nitrogen fixation and metabolism by groundwater-dependent perennial plants in a hyperarid desert.

The Central Asian Taklamakan desert is characterized by a hyperarid climate with less than 50 mm annual precipitation but a permanent shallow groundwater table. The perched groundwater (2-16 m) could present a reliable and constant source of nitrogen throughout the growing season and help overcome temporal nitrogen limitations that are common in arid environments. We investigated the importance of groundwater and nitrogen fixation in the nitrogen metabolism of desert plants by assessing the possible forms and availability of soil N and atmospheric N and the seasonal variation in concentration as well as isotopic composition of plant N. Water availability was experimentally modified in the desert foreland through simulated flooding to estimate the contribution of surface water and temporally increased soil moisture for nutrient uptake and plant-water relations. The natural vegetation of the Taklamakan desert is dominated by plants with high foliar nitrogen concentrations (2-3% DM) and leaf nitrate reductase activity (NRA) (0.2-1 micromol NO2- g(-1) FW h(-1)). There is little evidence that nitrogen is a limiting resource as all perennial plants exhibited fast rates of growth. The extremely dry soil conditions preclude all but minor contributions of soil N to total plant N so that groundwater is suggested as the dominant source of N with concentrations of 100 microM NO3-. Flood irrigation had little beneficial effect on nitrogen metabolism and growth, further confirming the dependence on groundwater. Nitrogen fixation was determined by the 15N natural abundance method and was a significant component of the N-requirement of the legume Alhagi, the average contribution of biologically fixed nitrogen in Alhagi was 54.8%. But nitrogen fixing plants had little ecological advantage owing to the more or less constant supply of N available from groundwater. From our data we conclude that the perennial species investigated have adapted to the environmental conditions through development of root systems that access groundwater to satisfy demands for both water and nutrients. This is an ecologically favourable strategy since only groundwater is a predictable and stable resource.

Atmosphere↗
PubMed2002

Inhibition of tobacco mosaic virus replication in lateral roots is dependent on an activated meristem-derived signal.

Viral invasion of the root system of Nicotiana benthamiana was studied noninvasively with a tobacco mosaic virus (TMV) vector expressing the green-fluorescent protein (GFP). Lateral root primordia, which developed from the pericycle of primary roots, became heavily infected as they emerged from the root cortex. However, following emergence, a progressive wave of viral inhibition occurred that originated in the lateral-root meristem and progressed towards its base. Excision of source and sink tissues suggested that the inhibition of virus replication was brought about by the basipetal movement of a root meristem signal. When infected plants were inoculated with tobacco rattle virus (TRV) expressing the red-fluorescent protein, DsRed, TRV entered the lateral roots and suppressed the host response, leading to a reestablishment of TMV infection in lateral roots. By infecting GFP-expressing transgenic plants with TMV carrying the complementary GFP sequence it was possible to silence the host GFP, leading to the complete loss of fluorescence in lateral roots. The data suggest that viral inhibition in lateral roots occurs by a gene-silencing-like mechanism that is dependent on the activation of a lateral-root meristem.

Gene Silencing↗
PubMed2002

Patterns of third molar impaction in a group of volunteers in Turkey.

The aim of this study was to investigate the different variables in mesio-vertically positioned impacted or erupted third molars in a group of volunteers in Turkey to determine the angular changes and levels of eruption radiographically using standardised panoramic radiographs. There were 213 volunteers with impacted and erupted third molars included in this study, most of whom were dental students. Standardised panoramic radiographs were taken from all the volunteers. The radiographic parameters included angulation of tooth, level of eruption, development of root, mesiodistal crown width, retromolar space, and gonial angle. Statistical analysis was done using the t-test for independent groups. It was found that the mesiodistal angulation of third molars was significantly greater while the retromolar space of third molars was significantly smaller in the impacted group (P<0.05). There was also a significant difference in retromolar space/third molar crown width ratio (P<0.05).

Adolescent↗
PubMed1982

A histological investigations of isografts of immature mouse molars to an intrabony and extrabony site.

Partially-developed teeth with remnants of their periodontal ligaments isografted to the tibial shaft medulla and renal subcapsular site were capable of progressive regeneration characterized by renewed tubular dentine formation. Bone formation occurred in relation to grafts at the renal site as well as the tibial shaft; evidence of periodontal fibre reorganization was observed in grafts at both sites. Despite post-transplantation dentine and cementum formation, continued development of roots of normal morphology did not occur, perhaps due to disappearance of epithelial root sheath.

Animals↗
PubMed1993

The effect of propranolol on salivary gland function and dental caries development in young and aged rats.

Medications commonly used in elderly people cause hyposalivation and are associated with an enhanced prevalence of dental caries. Propranolol (a beta-adrenergic antagonist) is a commonly used antihypertensive agent that is prescribed for long-term use. The purpose of this investigation was to compare the effects of this drug on salivary composition and flow rate, and on caries, in young and aged rats. Forty young (28-day) and 36 aged (20-month) female Sprague-Dawley rats were infected with Streptococcus sobrinus 6715 and fed a cariogenic diet for 28 days. Propranolol was given in high (20 mg/kg/day) and low (10 mg/kg/day) doses via osmotic pumps. Unoperated and desalivated animals served as controls. Smooth-surface caries scores in the young animals receiving propranolol at 20 mg/kg/day were statistically higher than in the young intact rats (p < or = 0.05). Increased smooth-surface and sulcal caries scores were recorded in the aged propranolol-treated animals, but the differences were not statistically significant when compared with those in intact aged animals. Propranolol in aged animals did not affect the amount of alveolar bone loss but increased the risk of development of root caries. Young animals harboured greater populations of Strep. sobrinus and total cultivable flora than did all aged groups except the desalivated group. Salivary flow rates, induced by pilocarpine, were not decreased by the chronic administration of propranolol. Although the total protein concentration in parotid and submandibular saliva from drug-treated animals was reduced, differences were not observed in their SDS-PAGE profile when compared with unoperated animals. The findings demonstrate that chronic use of propranolol reduced the total protein concentration in saliva of all animals, increased caries susceptibility, but did not reduce the stimulated salivary flow rate.

Aging↗
PubMed1983

Neuronal acquisition of tetanus toxin binding sites: relationship with the last mitotic cycle.

In an earlier study on the developing nervous system, the existence of a temporal correlation between the appearance of tetanus toxin-binding cells and neurogenesis was reported (A. Koulakoff, B. Bizzini, and Y. Berwald-Netter (1982). Dev. Brain Res. 5, 139-147). Using a combined approach of immunocytochemistry and [3H]thymidine autoradiography it is shown that, in the fetal mouse central nervous system, dividing cells do not express membrane binding sites for tetanus toxin. A time-course quantitative autoradiography revealed that the toxin-binding sites become apparent within 7 +/- 1 hr, following the last S phase, on cells undergoing the conversion from dividing to postmitotic state. The acquisition of surface binding sites for tetanus toxin may thus be an early property of nascent central neurons, marking the transition from cycling precursor neuroblasts to postmitotic neuronal cells. Parallel studies on in vivo-developing dorsal root ganglia disclosed that at least some peripheral nervous system cells are endowed with tetanus toxin-binding capacity while still capable of DNA synthesis and undergo one or more divisions.

Animals↗
PubMed1993

Predictive model for impaction of lower third molars.

The study was carried out to create and test a model for predicting impaction of lower third molars on the basis of radiographic findings at age 20 years. Fifty-six initially unerupted lower third molars were followed up for 6 years. Five radiographic findings in panoramic tomograms at age 20 were taken as variables. Clinical status at age 26 was taken as response. The radiographic features studied were angulation of tooth, development of root, state of impaction, depth in bone, and relation of the tooth to the ramus of the mandible and the second molar. With the use of logistic regression, univariate and bivariate analyses, and clustering techniques, a decision tree was constructed that indicated accuracies of prediction on the basis of single variables or pairs of variables. The most important predictor was the type of impaction. The model predictions and test teeth findings were in agreement in 94% of instances. It was concluded that the model is suitable for predicting lower third molar impaction at age 20.

Adult↗
PubMed1984

Use of the enzyme-linked immunosorbent assay (ELISA) for detection of Entamoeba histolytica antigen in faecal samples.

A promising new ELISA method developed by Root et al. to diagnose amoebiasis by the detection of Entamoeba histolytica coproantigen was tested in Mexico City and was reported to be more than twice as sensitive as microscopy. In this study the same procedure was compared to microscopy for paired specimens from 107 patients in San Francisco. Microscopy was more than twice as sensitive as ELISA: of 12 specimens positive by microscopy only 5 were also positive by ELISA. The ELISA did not detect a single specimen not detected by microscopy. Over-all, there was a 93% agreement between the two tests: 5% were positive and 89% negative by both tests. Possible reasons for the differences in the San Francisco and Mexican City findings are discussed.

Antigens, Protozoan↗
PubMed1995

Spinal and parachordal neurons in the eel leptocephali, Anguilla japonica revealed by labeling with a fluorescent dye.

The spinal and parachordal neurons innervating the trunk muscles and skin in the Japanese eel leptocephali, Anguilla japonica, were retrogradely labeled with a fluorescent dye, DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate). The spinal motoneurons innervating the trunk muscles were located in the medioventral part of the spinal cord and were divided into two populations on the basis of their soma sizes and position. The sensory neurons were labeled in the well-developed dorsal root ganglia, that were situated just peripheral to the meeting of the dorsal and ventral roots. Presumable postganglionic sympathetic neurons were also labeled in the sympathetic ganglia which were located ventrally to the notochord. Thus, the spinal and parachordal neurons innervating the trunk muscles and skin were firstly identified in the anguilliform leptocephalus.

Anguilla↗
PubMedDate not supplied

Solitary coronary ostium in the aorta in Syrian hamsters. A morphological study of 130 cases.

BACKGROUND: Solitary coronary ostium in the aorta (SCOA) is a rare anomaly, the pathogenesis of which remains uncertain. The lack of an animal model is one of the reasons why little understanding of this question has been gained. The aim was to examine the coronary distribution patterns associated with SCOA in laboratory inbred Syrian hamsters. METHODS: The study concerns 130 cases detected in a database consisting of 1,202 internal casts of the heart, great arterial trunks, and coronary arteries. RESULTS: In 21 (16.2%) cases, the solitary ostium was located in the left aortic sinus. In a further 58 (44.6%) cases, it was in the right aortic sinus. In the remaining 51 (39.2%) cases, the ostium was in the right side of the ventral aortic sinus of a bicuspid aortic valve. The distribution patterns were classified according to the location of the solitary ostium and the presence, or absence, and course of the main coronary arterial vessels. Overall, 14 categories were established, 10 of which had their counterpart in man. CONCLUSIONS: The findings reported substantiate the use of the present inbred Syrian hamsters for further studying the morphogenesis of the SCOA. The results of a statistical analysis indicate that when a sole coronary ostium becomes established in the aortic root, the development of the resultant anomalous coronary arterial tree tends to happen through preferential pathways. In addition, they indicate that the branching mode of the coronary tree and the condition of the aortic valve are independent traits.

Animals↗
PubMedDate not supplied

Cerebellar herniation after cervical transforaminal epidural injection.

OBJECTIVE: The purpose of this study is to inform readers of potential catastrophic complications associated with performing cervical transforaminal epidural steroid injections. CASE REPORT: A 31-year-old man presented to the pain clinic with a history of cervical radicular pain and right upper-extremity radicular symptoms. He was referred from the orthopedic spine clinic for evaluation for epidural steroid injection, having failed conservative treatment consisting of nonsteroidal anti-inflammatory drugs, muscle relaxants, oral steroids, and physical therapy. After undergoing a transforaminal epidural steroid injection at the right C8 nerve root, he developed a cerebellar infarct and brainstem herniation. He survived but has residual deficits of persistent diplopia on right lateral gaze and difficulties with short-term memory loss and concentration. CONCLUSIONS: Although transforaminal epidural steroid injections are an efficacious treatment for radicular syndromes, there can be catastrophic complications. In light of the growing body of similar case reports, further investigation is warranted to establish a safe protocol for the use of this modality.

Adult↗
PubMed2004

Modeling pandemic preparedness scenarios: health economic implications of enhanced pandemic vaccine supply.

Influenza pandemic planning is a complex, multifactorial process, which involves public health authorities, regulatory authorities, academia and industry. It is further complicated by the unpredictability of the time of emergence and severity of the next pandemic and the effectiveness of influenza epidemic interventions. The complexity and uncertainties surrounding pandemic preparedness have so far kept the various stakeholders from joining forces and tackling the problem from its roots. We developed a mathematical model, which shows the tangible consequences of conceptual plans by linking possible pandemic scenarios to health economic outcomes of possible intervention strategies. This model helps to structure the discussion on pandemic preparedness and facilitates the translation of pandemic planning concepts to concrete plans. The case study for which the model has been used shows the current level of global pandemic preparedness in an assumed pandemic scenario, the health economic implications of enhanced pandemic vaccine supply and the importance of cell culture-based influenza vaccine manufacturing technologies as a tool for pandemic control.

Disease Outbreaks↗