Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Nodule development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed1991

Rhizobium meliloti exopolysaccharides: genetic analyses and symbiotic importance.

Genetic experiments have indicated that succinoglycan (EPS I), the acidic Calcofluor-binding exopolysaccharide, of the nitrogen-fixing bacterium Rhizobium meliloti strain Rm1021 is required for nodule invasion and possibly for later events in nodule development on alfalfa and other hosts. Fourteen exo loci on the second megaplasmid have been identified that are required for, or affect, the synthesis of EPS I. Mutations in certain of these loci completely abolish the production of EPS I and result in mutants that form empty Fix- nodules. We have identified two loci, exoR and exoS, that are involved in the regulation of EPS I synthesis in the free-living state. Certain exo mutations which completely abolish EPS I production are lethal in an exoR95 or exoS96 background. Histochemical analyses of the expression of exo genes during nodulation using exo::TnphoA fusions have indicated that the exo genes are expressed most strongly in the invasion zone. In addition, we have discovered that R. meliloti has a latent capacity to synthesize a second exopolysaccharide (EPS II) that can substitute for the role(s) of EPS I in nodulation of alfalfa but not of other hosts. Possible roles for exopolysaccharides in symbiosis are discussed.

Genes, Bacterial↗
PubMed1989

Seasonal changes in nodular nitrogenase activity of Alnus glutinosa and Elaeagnus angustifolia.

Root nodule development, and seasonal patterns of nodular nitrogenase and hydrogenase activities were determined for 5- to 8-year old black alder (Alnus glutinosa (L.) Gaertn.) and Russian olive (Elaeagnus angustifolia L.) interplanted with black walnut (Juglans nigra L.) on bottomland and upland sites in central Illinois, USA. Black alder produced nodules at both sites, but Russian olive did so only at the bottomland site. Nodular nitrogenase activity was detectable in both species over a 220-day period. Maximum, midday rates of nitrogenase activity (acetylene reduction) of 15 to 20 micromoles C(2)H(4) per g dry nodule per hour were maintained by black alder for approximately 150 days at both the upland and bottomland sites. Near maximum rates of nodular nitrogenase activity were maintained for a similar period by Russian olive at the lowland site, although specific nitrogenase activity was approximately 25% lower than in black alder owing to a larger proportion of necrotic nodular tissue in Russian olive. In both species, nitrogenase activity increased exponentially with temperature between 10 degrees C and 20 to 25 degrees C. No net hydrogen evolution by nodules of either species was detected at any time during the assay period, indicating efficient hydrogenase systems were operating under the conditions of the field assay. Height of black walnut interplanted with nodulated black alder and Russian olive was greater than that of black walnut grown in pure stands.

Journal Article↗
PubMed1998

Acanthamoebiasis in Korea: two new cases with clinical cases review.

The first case was 7-month-old immunodeficiency girl in whom the diagnosis of Acanthamoeba pneumonia was established by culture of a bronchial washing. The patient had been ill for a month when she was admitted due to neonatal thrombocytopenia with respiratory difficulty and treated with gammaglobulin and steroid. Her chest X-ray showed diffuse alveolar consolidation on the left lung with interstitial hazziness and a partial sign of hyperinflation on the right lung. Laboratory tests showed that the Candida antigen was negative and Pneumocystis carinii was not detected. Mycoplasma antigen was negative. All the immunoglobulin levels (IgG, IgA, IgM) were below the normal range. Five days later the patient expired. The second case was an immunosuppressed 7-year-old boy in whom Acanthamoeba trophozoites were found in the skin biopsy, followed by meningitis leading to death. About five days after a laceration on the region of the left eyebrow, a painful bean-sized nodule developed at the suture site and it was treated with antibiotics and corticosteroid. The skin biopsy showed severe inflammatory cell infiltration. Trophozoites were scattered near the blood vessels throughout the inflammatory zone. From one weak prior to admission, the patient had suffered from vomiting, indigestion and mild fever. Skin nodules with tenderness appeared all over his body surface. Examination of cerebrospinal fluid showed clear, Gram stain was negative, bacterial culture negative, India ink preparation negative, and organism on wet smear negative. On admission day 10, focal seizure of the left extremity occurred. Brain CT revealed calcific density on the left parietal lobe area and hypodensity on the left basal ganglia. He became comatous and died immediately after discharge. Until now in Korea, two cases that are described in this paper, one Acanthamoeba meningoencephalitis case and seven Acanthamoeba keratitis cases including two unreported keratitis cases that are reported in this paper have been presented.

Acanthamoeba↗
PubMed1989

Molecular genetics of Rhizobium Meliloti symbiotic nitrogen fixation.

The application of recombinant DNA techniques to the study of symbiotic nitrogen fixation has yielded a growing list of Rhizobium meliloti genes involved in the processes of nodulation, infection thread formation and nitrogenase activity in nodules on the roots of the host plant, Medicago sativa (alfalfa). Interaction with the plant is initiated by genes encoding sensing and motility systems by which the bacteria recognizes and approaches the root. Signal molecules, such as flavonoids, mediate a complex interplay of bacterial and plant nodulation genes leading to entry of the bacteria through a root hair. As the nodule develops, the bacteria proceed inward towards the cortex within infection threads, the formation of which depends on bacterial genes involved in polysaccharide synthesis. Within the cortex, the bacteria enter host cells and differentiate into forms known as bacteroids. Genes which encode and regulate nitrogenase enzyme are expressed in the mature nodule, together with other genes required for import and metabolism of carbon and energy sources offered by the plant.

Journal Article↗
PubMed1999

Effect of salt stress on nodulation and nitrogen fixation in legumes.

It is now well established that almost all phases of root nodule development in legumes are adversely affected by saline conditions in the rooting medium. There is also a general agreement that the rhizobia are more tolerant to salt stress than the host plant, but they show considerable strain variability in growth and survival under saline conditions. Inhibitory effect of salinity on nodulation has been attributed to decrease in rhizobial colonisation and shrinkage and lack of root hair formation. Salt stress also induces premature senescence of already formed nodules. Both N2-fixation activity and nodule respiration are inhibited sharply on exposure of plants to saline conditions. The decrease in N2-fixation has been ascribed to direct effect on nitrogenase activity or an indirect effect through decrease in leghemoglobin content, respiratory rate, malate concentrations in nodules and photosynthate availability. Salinity increases oxygen diffusion resistance in the nodules and alters their ultrastructure. Decrease in N2-fixation in nodules under salinity is also accompanied by parallel decrease in the activity of H2O2-scavenging enzymes like catalase, ascorbate peroxidase and the level of antioxidants like ascorbic acid. Nodules appear to undergo osmoregulation under saline conditions by accumulating physiologically compatible solutes like proline, sugars (pinnitol) and lactic acid. The intensity of the adverse effects of salinity on nodule functioning depends on plant species, rhizobial strain, duration of exposure to saline conditions, nature, concentration and mode of salt application.

Fabaceae↗
PubMed1998

Lupus vulgaris complicated by metastatic squamous cell carcinoma.

A 47-year-old Bedouin man presented with an ulcerated nodule of several months' duration on the nape of the neck. The nodule developed on an asymptomatic, slowly growing plaque which appeared during childhood. Physical examination revealed two erythematous plaques covering the posterior and right lateral aspects of the neck. The border of the plaques was soft, circinate, with a reddish-brown color, while the center was slightly erythematous and atrophic. An ulcerated nodule measuring 2 cm was seen on one of the plaques. Physical examination was unremarkable with no lymphadenopathy. Laboratory tests, including complete blood cell count, erythrocyte sedimentation rate (ESR), and routine chemistry tests, were all within normal limits. Chest X-ray showed a small calcified perihilar lymph node. The Mantoux test was positive with erythema and induration of 15 mm after 48 h. Biopsy from a plaque showed extensive diffuse granulomatous infiltration throughout the dermis with epithelioid and Langhans giant cells surrounded by mononuclear inflammatory cells. No caseation necrosis was present. Ziehl-Neelsen, periodic acid-Schiff (PAS), and Giemsa stains were negative. Polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis and atypical mycobacteria from a skin sample was also negative. Fresh tissue cultures yielded M. tuberculosis after 6 weeks. A biopsy specimen from the ulcerated nodule demonstrated islands of atypical malignant squamous cells invading the dermis, which were compatible with moderately differentiated squamous cell carcinoma (SCC). The ulcerated nodule was completely excised, and treatment for tuberculosis was initiated with a combination of isoniazid, rifampicin, and pyrazinamide. Within 3 months of therapy, the patient's lesions resolved, leaving only slightly atrophic hypopigmented scars. A month after the treatment's initiation, an enlarged cervical lymph node was noted showing metastatic SCC on histologic examination. The patient underwent neck dissection and radiation therapy without evidence of any further metastases.

Carcinoma, Squamous Cell↗
PubMed1988

Pulmonary nodules simulating metastasis of germ cell tumor after aggressive chemotherapy.

We describe a patient in whom pulmonary nodules developed without infectious symptoms during treatment with bleomycin, cis-platinum, vinblastine and etoposide combination chemotherapy for metastatic extra-gonadal germ cell tumor. At thoracotomy only fibrosis was found. In this case, false-positive elevation of alpha-fetoprotein and the CT scan appearance made us interpret the pulmonary nodules as new metastatic lesions.

Adult↗
PubMedDate not supplied

Subcutaneous panniculitic T-cell lymphoma developing in a child with idiopathic myelofibrosis.

PURPOSE: Subcutaneous panniculitic T-cell lymphoma is reported in a child with idiopathic myelofibrosis. Both disease entities are rarely seen in children. PATIENT AND METHODS: A girl aged 5 years and 9 months had pancytopenia and severe constitutional symptoms. Idiopathic myelofibrosis was subsequently diagnosed. RESULTS: A transient response was achieved after treatment with a course of high-dose methylprednisolone therapy. However, proptosis and skin nodules developed during tapering of steroid therapy. A computed tomography scan of the orbit also revealed a mass lesion in the right lacrimal gland region. A skin biopsy specimen showed a subcutaneous panniculitic T-cell lymphoma. The clinical course was marked by high fever, profound pancytopenia, massive gastrointestinal bleeding, and severe, recurrent infections. Her condition rapidly deteriorated, and she died from polymicrobial sepsis 4 months after her initial examination. CONCLUSIONS: Subcutaneous panniculitic T-cell lymphoma is a distinctive clinicopathologic entity that is rarely seen in children. The association of myelofibrosis and peripheral T-cell lymphoma as seen in this has been rarely reported.

Child↗
PubMedDate not supplied

Histology and ultrastructural aspects of virus-induced primary liver cancer and transplantable hepatomas of viral origin in chickens.

The macroscopic, light microscopic and electron microscopic features and biological properties of MC-29 virus-induced hepatocellular carcinomas in chickens are described. The tumors developed in noncirrhotic livers within a very short time and formed metastases. Virus production was also evidenced in the tumors. There were also indications of virus production in the transplantable tumors. The tumors grew equally well after sc, ip, or im inoculation. In about 25% of the tumor-bearing animals, tumorous nodules developed in the liver. It could not be established whether they were metastases or primary liver cancers induced by viruses released from the transplantable tumors.

Animals↗
PubMed1990

Modulation of Host Gene Expression during Initiation and Early Growth of Nodules in Cowpea, Vigna unguiculata (L.) Walp.

Inoculation of 2-day-old cowpea (Vigna unguiculata [L.] Walp.) seedlings with Rhizobium fredii USDA257 results in proficient nodulation of the tap root. The most abundant nodulation occurs in a region roughly corresponding to the position of the root tip at the time of inoculation. We have examined plant gene expression in this region, after inoculation with either USDA257 or a nonnodulating mutant, 257B3. After isolation of mRNA and in vitro translation, the protein products were separated by two-dimensional gel electrophoresis. Seven proteins are induced within 2.5 days after inoculation with USDA257. One additional induced protein is detectable by 3.5 days after inoculation, and three more appear by day 6. Three of the proteins that are differentially expressed at 2.5 and 3.5 days after inoculation are produced at equivalent levels after 6 days, indicating transient induction of these genes during early stages of nodule development. Several proteins were more abundant in translations of mRNA from roots that had been inoculated with the nonnodulating mutant. This was particularly true after 6 days, when nine proteins were in this class. Thus, altered plant gene expression in carefully selected, highly responsive tissue can be detected 2 days before emerging nodules are visible on the roots, and 6 to 7 days before acetylene reduction is detectable. Additionally, comparisons of ionically bound cell wall proteins isolated 6 days after inoculation revealed four that were unique to nodulating roots, suggesting that some of the nodulation-induced genes may code for structural proteins.

Journal Article↗
PubMedDate not supplied

Thyroiditis and oncocytic carcinoma: incidental association? A case report.

BACKGROUND: Several studies have reported an association between Hashimoto's disease and thyroid carcinoma although the cause/effect relationship is still controversial. CASE REPORT: In this paper we report the case of a 38-year-old female who first presented with a clinical history of Hashimoto's thyroiditis. Ultrasound examination showed a diffuse thyroid irregularity more pronounced in the right lobe. FNAC (Fine Needle Aspiration Cytology) was performed in this area, and the cytological diagnosis was "Hashimoto's thyroiditis". The patient underwent clinical follow-up. Two years later, an ultrasound examination showed a nodular lump in the area previously aspirated. A new FNAC evidenced a Hurthle cell neoplasia. Therefore, the patient underwent surgery. The histological diagnosis was "Hurthle cell carcinoma". CONCLUSION: In the present case, the clinical and ultrasound history suggest the development of a malignant lesion strictly related to thyroiditis, as previously reported by other studies on papillary carcinoma. A cause-effect relationship between chronic lymphocytic thyroiditis and oncocytic neoplasia is still a matter of controversy. Therefore, patients suffering from chronic thyroiditis require a careful follow-up and, in case of nodules development, FNAC is recommended.

Adenoma, Oxyphilic↗
PubMed1989

Coordinated synthesis of leghemoglobin and root protein R18 in yellow lupin.

Uninfected roots of yellow lupin contain an abundant 18 kDa protein (referred to as R18), absent in the mature nodules. Some properties of this polypeptide are apparently similar to those of lupin leghemoglobins. However, the lack of any immuno crossreaction between R18 and leghemoglobin and differences in N-terminal amino acid sequences indicate that these proteins are coded by different genes. The decrease in the content of R18 protein in developing nodule is associated with the increased synthesis of leghemoglobin. This implies coordination of both events.

Amino Acid Sequence↗
PubMed1992

Nodular scleroderma in systemic sclerosis under D-penicillamine therapy.

A case of systemic sclerosis (SS) which developed keloidal lesions (nodular scleroderma) on the chest during D-penicillamine (DPC) therapy is reported. The 36-year-old woman showed rapidly progressing skin sclerosis with lung and esophageal involvement, and DPC was started at the age of 38. Skin sclerosis as a whole had improved to some extent, when keloidal nodules developed on the upper chest at the age of 44. Since there were no other findings suggestive of adverse reactions caused by DPC, we speculate that activation of the fibroblasts in these lesions occurred despite the suppressive effect of DPC.

Adult↗
PubMed1995

Significance of percutaneous needle biopsy in patients with multiple pulmonary nodules and a single known primary malignancy.

OBJECTIVE: To determine the necessity of percutaneous lung biopsy in patients with a single known primary malignancy and multiple pulmonary nodules. DESIGN: Retrospective study. SETTING: Tertiary care university hospital. RESULTS: We reviewed all percutaneous lung biopsy specimens over a 6-year period. One hundred forty-six patients with a single known primary malignancy and multiple pulmonary nodules had biopsies performed up to 19 years following diagnosis of the primary neoplasm. One hundred thirty-seven biopsy specimens (93.8%) were positive for metastases. Eight patients (5.5%) had a nondiagnostic biopsy specimen; however, subsequent imaging studies and the clinical course strongly suggested diffuse metastatic disease. One patient (< 1%) with breast carcinoma developed nodules 3 years after initial diagnosis and had resolution without a definitive diagnosis or therapy. CONCLUSION: Patients with a single known primary malignancy and multiple pulmonary nodules who present for percutaneous needle biopsy will have pulmonary metastases in the vast majority of cases. Biopsy in these patients rarely changes the clinical course as other diagnoses are rarely established.

Adolescent↗
PubMedDate not supplied

Well differentiated thyroid carcinoma: epidemiology, etiology and treatment.

The well differentiated thyroid carcinomas are uncommon but are increasing in frequency. This increase may be related to the recognition that even low doses of irradiation to the thyroid may be carcinogenic with a latency period of 10, 20 or more years to clinical tumor expression. Although unproven for human cancers, elevated TSH levels will enhance irradiation-associated tumor development in animal models. Currently, a large portion of the population is at an increased risk of developing thyroid cancer because of head and neck irradiation received from 1920 to 1950 for various benign conditions or more recently for the treatment of lymphoma or carcinoma. Whether these individuals should receive thyroid hormone suppression of TSH is not known but careful yearly evaluation is essential followed by open surgical biopsy chould a nodule develop. Treatment of the well differentiated thyroid carcinoma is controversial due to a lack of adequate long-term, controlled trials. Based on current data, it is the author's opinion that surgery should in most cases be followed with radioactive iodine ablation of all remaining tissue which can concentrate iodine followed by lifelong thyroid hormone replacement sufficient to correct hypothyroidism and suppress thyroid stimulating hormone. All patients require close follow-up with examination and, possibly, imaging for 20 or more years.

Adenocarcinoma↗
PubMed1991

Root Isoflavonoid Response to Grafting between Wild-Type and Nodulation-Mutant Soybean Plants.

It was previously reported that the hypernodulating soybean (Glycine max [L.] Merr.) mutants, derived from the cultivar Williams, had higher root concentration of isoflavonoid compounds (daidzein, genistein, and coumestrol) than did Williams at 9 to 12 days after inoculation with Bradyrhizobium japonicum. These compounds are known inducers of nod genes in B. japonicum and may be involved in subsequent nodule development. The current study involving reciprocal grafts between NOD1-3 (hypernodulating mutant) and Williams showed that root isoflavonoid concentration and content was more than twofold greater when the shoot genotype was NOD1-3. When grafted, NOD1-3 shoots also induced hypernodulation on roots of both Williams and NOD1-3, while Williams shoots induced normal nodulation on both root genotypes. This shoot control of hypernodulation may be causally related to differential root isoflavonoid levels, which are also controlled by the shoot. In contrast, the nonnodulating characteristic of the NN5 mutant was strictly root controlled, based on reciprocal grafts. Delayed inoculation (7 days after planting) resulted in greater nodule numbers on both NOD1-3 and Williams, compared with a seed inoculation treatment. The nodulation pattern of grafted plants was independent of whether the shoot portion was derived from inoculated seed or uninoculated seed, when grafted at day 7 onto seedling roots derived from inoculated seed. This observation, coupled with the fact that no difference existed in nodule number of NOD1-3 and Williams until after 9 days from seed inoculation, indicated that if isoflavonoids play a role in differential nodulation of the hypernodulating mutant and the wild type, the effect is on advanced stages of nodule ontogeny, possibly related to autoregulation, rather than on initial infection stages.

Journal Article↗
PubMed1990

Nuclear factors interact with conserved A/T-rich elements upstream of a nodule-enhanced glutamine synthetase gene from French bean.

The gln-gamma gene, encoding the gamma subunit of glutamine synthetase in French bean (Phaseolus vulgaris), is strongly induced during nodule development. We have determined the nucleotide sequence of a 1.3-kilobase region at its 5' end and have identified several sequences common to the promoter regions of late nodulin genes from other legume species. The 5'-flanking region was analyzed for sequence-specific interactions with nuclear factors from French bean. A factor from nodules (PNF-1) was identified that binds to multiple sites between -860 and -154, and a related but distinct factor (PRF-1) was detected in extracts from uninfected roots. PNF-1 and PRF-1 bound strongly to a synthetic oligonucleotide containing the sequence of an A/T-rich 21-base pair imperfect repeat found at positions -516 and -466. The same factors also had a high affinity for a protein binding site from a soybean leghemoglobin gene and appeared to be closely related to the soybean nodule factor NAT2, which binds to A/T-rich sequences in the lbc3 and nodulin 23 genes [Jacobsen et al. (1990). Plant Cell 2, 85-94]. Comparison of NAT2/PNF-1 binding sites from a variety of nodulin genes revealed the conservation of the short consensus core motif TATTTWAT, and evidence was obtained that this sequence is important for protein recognition. Cross-recognition by PNF-1 of a protein binding site in a soybean seed protein gene points to the existence of a ubiquitous family of factors with related binding affinities. Our data suggest that PNF-1 and PRF-1 belong to an evolutionarily conserved group of nuclear factors that interact with specific A/T-rich sequences in a diverse set of plant genes. We consider the possible role of these factors in coregulating the expression of gln-gamma and other late nodulin genes.

Amino Acid Sequence↗
PubMed2002

Multiple eruptive dermatofibromas in patients with systemic lupus erythematosus treated with prednisone.

Solitary dermatofibromas are a common occurrence, especially on the lower limbs of young women, while multiple dermatofibromas (MDF) are rare, accounting for less than 0.3% of all dermatofibromas and may suddenly develop in immunosuppressed patients. We report a patient with systemic lupus erythematosus (SLE) who developed MDF while she was taking oral prednisone. A 46-year-old woman presented in 1989 complaining of photosensitivity, arthralgias, fatigue, malaise and dyspepsia. The patient denied fever, Raynaud's phenomenon, oral ulcer and hair loss. On examination she presented a typical SLE malar rash. Erythrocyte sedimentation rate (ESR) was elevated (54 mm/h). Speckle patterned IgG/IgM antinuclear antibodies were present at 1/1280 titer. Antibodies anti Ro/SSA were detected by counterimmunelectrophoresis up to 1/8 titer. Other laboratory findings were negative or within normal limits. Systemic lupus erythematosus was diagnosed and the patient given 50 mg/day prednisone. After a few months, both clinical symptoms and immunologic parameters improved. Eighteen months later, prednisone was replaced by 500 mg/day hydroxychloroquine. In 1994, she presented again with malar rash, arthralgias and facial hyperpigmentation. Prednisone 15 mg/day was reintroduced and hydroxychloroquine stopped being a possible cause of the facial hyperpigmented macules. In 1996, while she was taking 5 mg/day prednisone, several nodules developed on her limbs within a few months. On examination we observed 16 firm, slightly elevated 3-15-mm wide brown nodules on her arms, legs and trunk. A biopsy specimen of a lesion of the trunk revealed an epidermal seborrheic-keratosis-like hyperplasia with dermal fibrosis and fibroblastic proliferation (Fig. 1). Dermatofibroma was diagnosed.

Anti-Inflammatory Agents↗