Transposable Elements and Genome Size Variations in Plants

Although the number of protein-coding genes is not highly variable between plant taxa, the DNA content in their genomes is highly variable, by as much as 2,056-fold from a 1C amount of 0.0648 pg to 132.5 pg. The mean 1C-value in plants is 2.4 pg, and genome size expansion/contraction is lineage-specific in plant taxonomy. Transposable element fractions in plant genomes are also variable, as low as ~3% in small genomes and as high as ~85% in large genomes, indicating that genome size is a linear function of transposable element content. Of the 2 classes of transposable elements, the dynamics of class 1 long terminal repeat (LTR) retrotransposons is a major contributor to the 1C value differences among plants. The activity of LTR retrotransposons is under the control of epigenetic suppressing mechanisms. Also, genome-purging mechanisms have been adopted to counter-balance the genome size amplification. With a wealth of information on whole-genome sequences in plant genomes, it was revealed that several genome-purging mechanisms have been employed, depending on plant taxa. Two genera, Lilium and Fritillaria, are known to have large genomes in angiosperms. There were twice times of concerted genome size evolutions in the family Liliaceae during the divergence of the current genera in Liliaceae. In addition to the LTR retrotransposons, non-LTR retrotransposons and satellite DNAs contributed to the huge genomes in the two genera by possible failure of genome counter-balancing mechanisms.

Efficacy of strain RB51 vaccine in protecting infection and vertical transmission against Brucella abortus in Sprague-Dawley rats

Immunizing animals in the wild against Brucella (B.) abortus is essential to control bovine brucellosis because cattle can get the disease through close contact with infected wildlife. The aim of this experiment was to evaluate the effectiveness of the B. abortus strain RB51 vaccine in protecting infection as well as vertical transmission in Sprague-Dawley (SD) rats against B. abortus biotype 1. Virgin female SD rats (n = 48) two months of age were divided into two groups: one group (n = 24) received RB51 vaccine intraperitoneally with 3 x 10(10) colony forming units (CFU) and the other group (n = 24) was used as non-vaccinated control. Non-vaccinated and RB51-vaccinated rats were challenged with 1.5 x 10(9) CFU of virulent B. abortus biotype 1 six weeks after vaccination. Three weeks after challenge, all rats were bred. Verification of RB51-vaccine induced protection in SD rats was determined by bacteriological, serological and molecular screening of maternal and fetal tissues at necropsy. The RB51 vaccine elicited 81.25% protection in SD rats against infection with B. abortus biotype 1. Offspring from rats vaccinated with RB51 had a decreased (p < 0.05) prevalence of vertical transmission of B. abortus biotype 1 compared to the offspring from non-vaccinated rats (20.23% and 87.50%, respectively). This is the first report of RB51 vaccination efficacy against the vertical transmission of B. abortus in the SD rat model.

Electron microscopic study of adhesion between Helicobacter pylori and gastric epithelial cell / 대한내과학회지

BACKGROUND: The purpose of this study was to investigate the ultrastructural relation of H. pylori and gastric epithelial cells in their adhesion. METHODS: Endoscopic biopsy of gastric antrum and body was performed from 15 patients (9 men, 6 women) with chronic gastritis. These specimens were processed and observed by transmission electron microscope (Hitachi H-600). RESULTS: On the basis of morphological appearances, the different types of adhesion of the organism with the epithelial cells were categorized as filamentous connection, adhesion pedestals, membrane fusion. Coccoid and intermediate forms were associated with filamentous connection whereas bacillary forms were associated with adhesion pedestals and membrane fusion. CONCLUSION: Various types of adhesion were associated with H. pylori and gastric epithelium. Further studies are needed to investigate biophysiologic influence to epithelial cells by ultrastructural relationship.(Korean J Med 60:16-21, 2001)

Multifaces of Sonographic Findings of Galactocele: Comparison According to it's Association with Pregnancy

PURPOSE: To compare the sonographic findings of galactocele according to it's association with pregnancy. MATERIALS AND METHODS: We rev i ewed the sonographic findings of 21 lesions in 20 patients confirmed by surgery (n=15) or fine needle aspiration (n=6) as galactoceles. The patients were divided into two groups, according to the period from the most recent pregnancy or lactation. In the first group(n=8, mean age=28.6 years), this was less than one year and in the second group(n=13, mean age=45.6 years), was more than one year. RESULTS: In our study, pregnancy-unrelated galactoceles (n=13) were more common than pregnancy-related galactoceles (n=8). The sonographic findings of galactocele of the first group were as follows; ovoid anechoic cystic mass (n=5), cystic mass with fat-fluid level (n=2), and well defined heterogeneous mass (n=1). Those of the second group were as follows; irregularly bordered deeply hypoechoic mass (n=3), irregularly bordered hypoechoic mass with internal nodules (n=3), homogeneous hypoechoic mass with smooth margin (n=4), and lobulated anechoic mass with posterior acoustic enhancement and internal debris (n=3). CONCLUSION: Pregnancy-unrelated galactoceles demonstrated the variable sonographic findings of solid f mass, whereas most of pregnancy-related galactoceles demon-strated the sonographic features of cysts.

Differential CT Features between Malignant Mesothelioma and Pleural Metastasis from Lung Cancer or Extrathoracic Primary Tumor Mimicking Malignant Mesothelioma

PURPOSE: To evaluate the differential CT features found among malignant mesothelioma and pleural metastasis from lung cancer and from extrathoracic primary tumor which on CT mimic malignant mesothelioma. MATERIALS AND METHODS: Forty-four patients who on chest CT cans showed pleural thickening suggesting malignant pleural disease and in whom this condition was pathologically confirmed were included in this study. On the basis of their pathologically proven primary disease [malignant mesothelioma (n=14), pleural metastasis of lung cancer (n=18), extrathoracic primary tumor (n=12)]. they were divided into three groups. Cases of lung which on CT showed a primary lung nodule or endobronchial mass with pleural lesion, or manifested only pleural effusion, were excluded. The following eight CT features were retrospectively analyzed: 1) configuration of pleural lesion (type I, single or multiple separate nodules, type II, localized flat pleural thickening, type III, diffuse flat pleural thickening; type IV, type III with pleural nodules superimposed; type V, mass filling the hemithorax), 2) the presence of pleural effusion, 3) chest wall or rib invasion, 4) the involvement of a major fissure, 5) extrapleural fat proliferation, 6) calcified plaque, 7) metastatic lymph nodes, 8) metastatic lung nodules. RESULTS: In malignant mesothelioma, type IV (8/14) or II (4/14) pleural thickening was relatively frequent. Pleural metastasis of lung cancer favored type IV (8/18) or I (6/18) pleural thickening, while pleural metastasis from extrathoracic primary tumor showed a variable thickening configuration, except type V. Pleural metastasis from lung cancer and extrapleural primary tumor more frequently showed type I configuration than did malignant mesothelioma, and there were significant differences among the three groups. Fissural involvement, on the other hand, was significantly more frequent in malignant mesothelioma than in pleural metastasis from lung cancer or extrapleural primary tumor . Metastatic lymph nodes and metastatic lung nodules were significantly more frequent in pleural metastasis from lung cancer and extrapleural primary tumor than in malignant mesothelioma. CONCLUSION: Malignant mesothelioma showed significantly frequent fissural involvement and the frequency with which pleural metastasis from both lung cancer and extrathoracic primary tumor showed type I pleural lesion, metastatic lymph nodes or metastatic lung nodules, was significantly frequent. Even though no CT features for differentiating between pleural metastasis from lung cancer and from extrathoracic primary tumor were found, the CT features stated above would help differentiate malignant mesothelioma from the other two groups.

Differential Diagnosis of the Pancreatic Diseases: Significance of Perivascular Changes at Celiac trunk andSuperior Mesenteric Artery on CT

PURPOSE: To classify perivascular change in the celiac trunk and SMA occurring in pancreatic disease and toevaluate its significance in differential diagnosis. MATERIALS AND METHODS: In 73 patients with pancreaticdisease (42, acute pancreatitis; 14, chronic pancreatitis; 17, panreatic cancer) abdominal CT findings wereretrospectively reviewed. We defined " infiltration" as linear or irregular density and "thickening" as presenceof a soft tissue mantle surrounding the vessel, and statistically evaluated the usefulness of these factors forthe differential diagnosis of pancreatic diseases. RESULTS: In 13/42 cases of acute pancreatitis (31%), 4/14 ofchronic pancreatitis (28.6%), and 6/17 of pancreatic cancer (35.3%), periceliac infiltration was observed; thefrequencies were not statistically significant (p=0.916). Peri-SMA infiltration was demonstrated in 9/42 of acutepancreatitis (21.4%), 4/14 of chronic pancreatitis (28.6%), and 5/17 of pancreatic cancer (29.4%); again, thesefrequencies were not statistically significant (p=0.758). Thickening of the celiac trunk and SMA was observed onlyin pancreatic cancer, in 3/17 (17.6%) and 7/17(41.2%) cases, respectively, with statistical significance (p<0.05). CONCLUSION: Thickening of the celiac trunk and SMA is a valuable finding in the differential diagnosis ofpancreatic inflammatory disease and pancreatic cancer. When applied to the differential diagnosis of pancreaticdisease, perivaseular change should be classified as either infiltration or thickening.

The Changes of Bacillary and Granularity Indices of Mycobacterium Leorae Under DDS Therapy / 대한피부과학회지

The authors investigated serial changes of bacillary and granularity indices from 49 previously non-treated lepromatous leprosy patients under DDS therapy during 24 month period, and the following results were obtained. 1) Pretreatment bacillary index was highest on eye brows, and chins, ear lobes, arms, legs, backs in decreasing order. The proportion of fall of B.I. during therapy showed similar tendencies in each site of smears, the average decrease being 1. 2 in the first year and 0. 8 in the second year. 2) The average granularity index before therapy was 2. 5, the rise of G.I. was rapid during first 12 months, slower during next 6 months, and no significant changes were seen during last 6 months. 3) The changes of G.I. were faster and more sensitive to therapy than that of B.I. Therefore, it. seems more valuable assesing the response of therapy, drug resistance, prognosis, etc 4) 300 mg of DDS per week appears to be sufficient for maintaining the therapeutic dosage.