Germline mutations in BMPR1A/ALK3 cause a subset of cases of juvenile polyposis syndrome and of Cowden and Bannayan-Riley-Ruvalcaba syndromes

Juvenile polyposis syndrome (JPS) is an inherited hamartomatous-polyposis syndrome with a risk for colon cancer. JPS is a clinical diagnosis by exclusion, and, before susceptibility genes were identified, JPS could easily be confused with other inherited hamartoma syndromes, such as Bannayan-Riley-Ruvalcaba syndrome (BRRS) and Cowden syndrome (CS). Germline mutations of MADH4 (SMAD4) have been described in a variable number of probands with JPS. A series of familial and isolated European probands without MADH4 mutations were analyzed for germline mutations in BMPR1A, a member of the transforming growth-factor beta-receptor superfamily, upstream from the SMAD pathway. Overall, 10 (38%) probands were found to have germline BMPR1A mutations, 8 of which resulted in truncated receptors and 2 of which resulted in missense alterations (C124R and C376Y). Almost all available component tumors from mutation-positive cases showed loss of heterozygosity (LOH) in the BMPR1A region, whereas those from mutation-negative cases did not. One proband with CS/CS-like phenotype was also found to have a germline BMPR1A missense mutation (A338D). Thus, germline BMPR1A mutations cause a significant proportion of cases of JPS and might define a small subset of cases of CS/BRRS with specific colonic phenotype.     

Localization of anchor loci representing five hundred annotated rice genes to wheat chromosomes using PLUG markers

PCR-based Landmark Unique Gene (PLUG) markers are EST-PCR markers developed based on the orthologous gene conservation between rice and wheat, and on the intron polymorphisms among the three orthologous genes derived from the A, B and D genomes of wheat. We designed a total of 960 primer sets from wheat ESTs that showed high similarity with 951 single-copy rice genes. When genomic DNA of Chinese Spring wheat was used as a template, 872 primer sets amplified one to five distinct products. Out of these 872 PLUG markers, 531 were assigned to one or more chromosomes by nullisomic-tetrasomic analysis. For each wheat chromosome, the number of loci detected ranged from 32 for chromosome 6A to 73 for chromosome 7D, with an average of 48 loci per chromosome. Several novel synteny perturbations were identified using deletion bin-mapping of markers. Furthermore, we demonstrated that PLUG markers can be used as probes to simultaneously identify BAC clones that contain homoeologous regions from all three genomes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Metabolic engineering of Escherichia coli for 1-butanol production

Compared to ethanol, butanol offers many advantages as a substitute for gasoline because of higher energy content and higher hydrophobicity. Typically, 1-butanol is produced by Clostridium in a mixed-product fermentation. To facilitate strain improvement for specificity and productivity, we engineered a synthetic pathway in Escherichia coli and demonstrated the production of 1-butanol from this non-native user-friendly host. Alternative genes and competing pathway deletions were evaluated for 1-butanol production. Results show promise for using E. coli for 1-butanol production.     

A case report of infantile cystic nephroblastoma

Background

Nephroblastoma (NB) is a malignant embryonal neoplasm derived from nephrogenic blastemal cells. NB usually forms a solid mass, but in extremely rare cases, it may show cystic changes.

Case presentation

A six-month-old girl with persistent high fevers was found to have pyuria and bacteriuria. Ultrasonography revealed multilocular cysts in the right kidney. Right nephrectomy was performed with cyst wall rupture during surgery. An intraoperative rapid diagnosis, based on peritoneal fluid cytology, confirmed three components of blastemal, stromal, and epithelial cells. The blastemal cells were dyshesive, with scant to no cytoplasm and were the predominant cell type. The spindle-shaped stromal cells were arranged in fascicles. The epithelial cells demonstrated tubular structures. Macroscopically, the resected cystic tumor measured 80 mm in maximum diameter with a prominently thin cyst wall, but solid areas were also apparent. Histologically, the tumor was diagnosed as cystic NB (blastemal-predominant) displaying a triphasic pattern. Hyperchromatic nuclei and apoptotic bodies were found. The clinical stage classification of Japan Wilms Tumor Study group was 3. The patient was treated with chemotherapy and radiotherapy. Tumor recurrence and metastasis have not been observed in the 8 months since surgery.

Conclusion

This is an extremely rare case of infantile cystic NB. We diagnosed the NB cells that appeared in the peritoneal fluid by intraoperative rapid cytology. Cytological examination proved to be a very useful technique for determining the clinical stage of NB. Additionally, we propose that massive tumor degeneration and necrosis be considered as a pathogenic mechanism of cyst formation in NB.

     

PREMATURE CHROMOSOME CONDENSATION OF THE KARYOGAMY-BLOCKED SPERM PRONUCLEUS IN THE FERTILIZATION OF FUCUS DISTICHUS (FUCALES,PHAEOPHYCEAE)1

Mitosis of egg and sperm pronuclei of Fucus distichus subsp. evanescens (C. Agardh)Powell was examined by fluorescence and electron microscopy when migration of the sperm pronucleus and, as a result, karyogamy were blocked by colchicine treatment after plasmogamy. Chromosome condensation was obsewed in both pronuclei Microspectrophotometric studies after staining the nuclei with mithramycin A clearly showed that DNA synthesis ocurred in the egg pronucleus but not in the sperm pronucleus. This means that chromosomes condensed prematurely in the sperm pronucleus (premature chromosome condensation). In some cases, the egg chromosomes became arranged on a metaphase plate, whereas the sperm chromosomes lay scattered near the egg pronucleus. Immuno fluorescence microscopy using anti-β-tubulin antibody confirmed that a normal spindle was formed at the egg pronucleus. A pair of centrioles existed at the two poles of this spindle. The sperm nuclear membrane disappeared, and microtubules radiated to the sperm chromosomes from one pole of the egg spindle.     

COORDINATNE NUCLEAR AND CHLOROPLAST DIVISION IN UNILOCULAR SPORANGIA OF LAMINARIA ANGUSTATA (LAMINARIALES,PHAEOPHYCEAE)1

Changes in the number of nuclei and chloroplasts were examined during the process of unispore formation in unilocular sporangia of Laminaria angustata. Just before meiosis, eight chloroplasts were always present in unilocular sporangial mother cells. The number of chloroplasts remained constant through meiosis. After the resulting four nuclei divided again (third nuclear division), a close association between a nucleus and a chloroplast developed among each of the eight nuclei and eight chloroplasts. The eight chloroplasts divided ahost synchronously before the synchronous division of the eight nuclei. Following the 16 nucleate stage with 16 chloroplasts and the final 32 nucleate stage with 32 chloroplasts, 32 unispores, each with a nucleus and a chloroplast, were fomd in unilocular sporangza of L. angustata. Immunofluorescence microscopy using an anti-centrin antibody showed that two anticentrin-stained structures (as future mitotic poles) occurred adjacent to each of the premitotic four nuclei, and each spot was located near a chloroplast. Therefore, after the third division, each of the eight nuclei established close contact with a chloroplast presumably mediated by the centrosomes.     

Immunofluorescence study of mitosis and cytokinesis in Acrosiphonia duriuscula (Acrosiphoniales,Chlorophyta)*

The behaviors of nuclei and microtubules (MT) in Acrosiphonia duriuscula (Ruprecht) Collins were observed in detail using fluorescence and electron microscopy. Numerous nuclei exist in cells of A. duriuscula (multinucleate cells). Cortical MT radiate from the apex of the tip cell and run parallel to its long axis. Between 30 and 40% of nuclei in the upper part of cytoplasm migrate downward to the region where cytokinesis will take place, and these numerous nuclei form a ‘nuclear ring’ before mitosis. The parallel array of the cortical MT changes to a transverse orientation at the region where cytokinesis will take place, and finally forms a characteristic circumferential band. Mitosis starts from the nuclei in the ring. Cortical MT disappear in the region of the nuclear ring and many mitotic spindles form. The band-shaped array of MT remains. Mitosis spreads in an apparent wave to the other nuclei. After mitosis, daughter nuclei that formed a nuclear ring migrate apically and repopulate the apical daughter cell. When the numerous daughter nuclei have relocated, a rearrangement of the cortical MT occurs. They are randomly arranged at first, but finally become parallel to the long axis of the cell. Cytokinesis occurs by furrowing of the cell, and the band-shaped array of MT could be detected at the leading edge of the furrow.     

Guluronate content of alginate in Laminaria japonica and Laminaria angustata fronds in laboratory culture

The guluronate (G) content of alginate in the fronds of Laminaria japonica and Laminaria angustata, cultured in the laboratory from zoospore via gametophyte using PESI medium, was determined by the ¹H‐nuclear magnetic resonance spectroscopic method. The G content of alginates in young fronds cultured in various conditions were shown to exceed 55%. These values were remarkably higher than those in field kelp. The G content increased with extending culture period and at low temperature.     

Effect of intraventricular injection of muscimol on appetite in rats kept at high and temperate ambient temperatures

The central mechanism controlling food intake in response to the change in environmental temperature has been little examined. The GABA agonist, muscimol, was injected into the lateral ventricle of rats which were acclimated to temperate (26 degrees C) and hot (33 degrees C) environments. Muscimol obviously stimulated the feeding behavior of rats in both environments. However, when muscimol was administered at doses of 100 and 250 ng, the food intake at 26 degrees C was greater than that at 33 degrees C. In addition, the stimulating effect of muscimol (250 ng) on food intake at 26 degrees C lasted longer than that at 33 degrees C. These findings suggested that there might be a difference in muscimol metabolism at the two temperatures.     

Lunula corneae in man and primates

Imai (1931) discovered a milk-white crescent on the temporal side of the cornea in Macaca cyclopis. Afterwards he confirmed that such a crescent appears in many kinds of primates, humans and newborn babies in Japan. It was named “Lunula corneae” by Professor S. Adachi. Both workers investigated the nature of the Lunula and considered the meaning of its appearance. Further study on the same problem was carried out by the present authors, when non-transparent tissues as the pactinate ligament and sclera over the ligament. When these tissues situate under the cornea due to the spread of it, they appear as a milk-white crescent. Moreover, the present authors made a statistical investigation on the remains of the Lunula corneae, observed the crescents which were accompanied by the pigmentation in the bulbar conjunctiva and investigated from a hereditary point of view the remains of the Lunula in the Japanese.They established that the Lunula corneae on the temporal side is a sign of the enlargement of the cornea to that side, resulting in a larger visual field on the same side. This is advantageous to primates who live in the open; they exhibit the Lunula throughout life. As concerns humans in Japan, the Lunula always appears in newborn babies, but gradually disappears with age and decreases to 15·7% at 23 years of age. Accordingly, the authors consider the Lunula in man is a kind of rudiment. The Lunula in man is accompanied by the pigmentation in the bulbar conjunctiva in a very high percentage of cases. The authors envisage such a pigmentation in man as a kind of pithecoid mark. Therefore, anthropological investigations on the Lunula corneae and the pigmentation around it would be an interesting subject for study. The authors also gained an insight of the hereditary nature of the Lunula remains. In their opinion such a character is transmittable in man.