bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein Pattern and Fe‐Superoxide Dismutase Activity of Bean Plants under Sulphur Dioxide Stress
Authors: Bernardi R. , Nali C. , Gargiulo R. , Pugliesi C. , Lorenzini G. , Durante M.
Published: August 2010

Protein synthesis and superoxide dismutase (SODs) activities were analysed in bean plants (Phaseolus vulgaris L., cv. Groffy) exposed to sulphur dioxide (SO2) (30, 60 or 90 nl/l SO2). After long‐term treatments (2, 4 or 7 days), sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) of water‐soluble leaf proteins revealed the appearance of new polypeptides corresponding to 34.5 and 31 kDa. Quantitative differences between control and treated plants were observed for subunits of 50, 47, 42, 32, 30 and 28 kDa. In SO2‐fumigated plants, the activity patterns of four SOD‐isoforms, with a relative mobility (Rf) of 0.45 (MnSOD), 0.59 (Cu/ZnSOD), 0.80 (Cu/ZnSOD) and 0.85 (not identified), showed only small quantitative variations in comparison with unexposed plants. In control leaves the FeSOD isoenzyme was not detected, whereas its activity pattern (Rf=0.50) increased to a detectable level always after 2 days of fumigation with 30 nl/l SO2. It is proposed that the rise of FeSOD activity represents the initial activation of the enzymatic antioxidant system to counteract the superoxide anion generated during the radical‐initiated oxidation of SO2 in illuminated chloroplasts.
The Influence of o‐hydroxyethylorutin on Botrytis cinerea Oxidant–Antioxidant Activity
Authors: Małolepsza U.
Published: August 2010

The objective of this study was to evaluate the effects of o‐hydroxyethylorutin on Botrytis cinerea mycelium growth and metabolism. Hydrogen peroxide concentration, superoxide dismutase, catalase and peroxidase activities were compared in the pathogens’ mycelium grown on control and o‐hydroxyethylorutin containing medium. Transfer of B. cinerea mycelium to medium supplemented with 5 mmo‐hydroxyethylorutin resulted in a large decrease in catalase activity. No changes in mycelium growth, hydrogen peroxide concentration and superoxide dismutase activity were observed. Guaiacol and ascorbate peroxidases were not detected in mycelia. The data are consistent with previous findings that o‐hydroxyethylorutin treatment of tomato plants restricts the development of B. cinerea infection due to the induction of higher active oxygen species (AOS) generation in plants by this compound. Being poor in catalase, the pathogen may not be able to cope with increasing AOS formation. The results indicate that catalase is an infective agent of B. cinerea.
Barium aspiration showing crazy‐paving appearance on high‐resolution computed tomography
Authors: Akata S , Park J , Shindo H , Yoshimura M , Kakizaki D , Abe K
Published: August 2010

We encountered a case showing a crazy‐paving appearance on high‐resolution computed tomography (HRCT), which mimicked various pulmonary diseases, e.g. pulmonary alveolar proteinosis, or non‐specific interstitial pneumonia, but which we ultimately determined to be due to barium aspiration. The initial radiological findings were considered to be most likely due to pulmonary alveolar microlithiasis, because the crazy‐paving appearance had high density, resembling calcification. However, distribution was limited to the area of dependent drainage of the right lung. Since a barium swallowing study had been performed 2 weeks before the CT examination, and since the follow‐up HRCT showed improvement we reached a diagnosis of barium aspiration. Although barium aspiration may yield findings similar to other diseases with crazy‐paving appearance, it is possible to identify it because of the limited distribution and high density.
Combined treatment of ablative therapy with percutaneous radiofrequency and cementoplasty of a symptomatic metastatic lesion of the acetabulum
Authors: Carrafiello G , Laganà D , Recaldini C , Mangini M , Giorgianni A , Cuffari S , Dionigi G , D’Angelo F , Fugazzola C
Published: August 2010

We report the case of a symptomatic metastatic lesion of the acetabulum from colon adenocarcinoma in an 82‐year‐old woman patient treated by a combined approach of thermal ablation with percutaneous radiofrequency and cementoplasty. We obtained an immediate technical success with a good control of pain without any complications at a 6‐month clinical follow‐up.
Management of iatrogenic porto‐biliary fistula following biliary stent
Authors: Chaitowitz IM , Heng R , Bell KW
Published: August 2010

We describe a case of cystic pancreatic disease causing biliary obstruction requiring percutaneous biliary stenting. The patient subsequently re‐presented with severe melaena shown to be due to a rare complication of biliary stenting with development of a porto‐biliary fistula from stent erosion, successfully managed with a ‘stent‐within‐stent’.
Herniation of caecum through the foramen of Winslow
Authors: Da Costa G , Ng B , Kociumbas I , Wong S
Published: August 2010

The radiological features on plain abdominal imaging and CT in a case of caecal herniation through the foramen of Winslow is presented. This rare condition is associated with a high morbidity and mortality, which emphasizes the importance of accurate preoperative diagnosis.
A child with respiratory distress having unilateral obstructive emphysema and contralateral opaque hemithorax on chest radiograph: Role of multi‐detector computerized tomography with multi‐planar reconstruction and virtual bronchoscopy
Authors: Debnath J , Jain NK , Adhikari KM , Shelley SK , Vaidya A , George RA
Published: August 2010

We describe a case of mucus plug in the right main bronchus with ipsilateral obstructive emphysema and contralateral opaque hemithorax in an 18‐month‐old girl who presented with respiratory distress. The role of multi‐detector CT scan with multi‐planar reconstructions and virtual bronchoscopy is highlighted.
Primary serous papillary carcinoma of the retroperitoneum: magnetic resonance imaging findings with pathologic correlation
Authors: Demir MK , Unlu E , Genchellac H , Temizoz O , Ozdemir H
Published: August 2010

The incidence of a primary serous papillary carcinoma of the retroperitoneum is extremely rare. We present a case of the tumour in an adult simulating an adrenal mass with MRI findings and histopathological correlation.
Percutaneous intracorporeal lithotripsy of biliary calculi
Authors: Hoang JK , Little AF , Clarke A
Published: August 2010

The standard management for patients presenting with bile duct calculi is endoscopic retrograde cholangiopancreatography and sphincterotomy with stone retrieval. In failed cases and for intrahepatic duct stones, there are a number of non‐operative alternative extraction methods. We describe two cases of percutaneous intracorporeal lithotripsy for biliary calculi and review the literature regarding the indications, complications and success rate.
Cemento‐ossifying fibroma of mandible
Authors: Hombal AG , Hegde KK , Narvekar VN
Published: August 2010

Cemento‐ossifying fibromas are relatively rare benign, non‐odontogenic tumours of the jaw, a subdivision of fibro‐osseous lesions. These tumours occur in the third and fourth decades of life, with predilection for women. Majority of the lesions are found in the posterior region of the mandible. We present a rare case of cemento‐ossifying fibroma involving the mentum of the mandible in a 50‐year‐old lady and discuss the plain radiographic and computed tomographic features of the condition.
Magnetic resonance imaging findings in chronic inflammatory demyelinating polyneuropathy with intracranial findings and enhancing, thickened cranial and spinal nerves
Authors: Kale HA , Sklar E
Published: August 2010

Chronic inflammatory demyelinating polyneuropathy is a rare autoimmune disorder characterized by chronically progressive or relapsing symmetric sensorimotor involvement. We describe the imaging findings in our patient. Magnetic resonance imaging showed presence of an intracranial white matter lesion and enhancing, thickened cranial and spinal nerves. This disorder has been described very infrequently in the radiology literature.
Bag of worms
Authors: McGuinness B , Soh MC , Kumar S , Donald J
Published: August 2010

A Pacific Island male with previously diagnosed but untreated filariasis with episodic chyluria presented to us with spiking temperatures. A CT scan of his abdomen revealed innumerable serpiginous non‐enhancing structures within the posterior mediastinum from the carina, throughout the retroperitoneum and pelvis and into the upper inguinal regions. This abnormality involved the hilar regions of both kidneys. The temperatures eventually settled after treatment with doxycycline for filiriasis.
Hamartoma of the breast
Authors: Murat A , Ozdemir H , Yildirim H , Poyraz AK , Ozercan R
Published: August 2010

Breast hamartoma is a rare benign tumour that leads to unilateral breast enlargement without a palpable localized mass lesion. Histologically, a hamartoma consists of varying amounts of adipose, gland, fibre and smooth muscle tissue. The characteristic mammographic appearance of hamartoma of breast has distinct mammographic features with circumscription and fat and soft‐tissue density surrounded by a thin radiopaque capsule or pseudocapsule. Ultrasonographic findings include a well‐defined mass lesion consisting of echogenic and sonolucent areas. We present histopathological and radiological findings of a 42‐year‐old female patient with breast hamartoma who has no complaint.
Herniation of the gall bladder through the abdominal wall
Authors: Pijpers M , Hazebroek EJ , Coene PPLO , Beerman H , Vroegindeweij D
Published: August 2010

We present a case of an 81‐year‐old woman, without medical history, with a swelling in the right lateral abdominal wall. Ultrasound and multislice CT were sufficient to confirm the diagnosis of a herniated gall bladder through the abdominal wall. This is the first case in which MRI proved to be a useful modality to exclude malignant characteristics and revealed an accurate differentiation between the gall bladder and the different layers of the abdominal wall. The gall bladder, including three stones, was removed laparoscopically. Histopathological research revealed signs of a chronic cholecystitis. Herniation of the gall bladder through the abdominal wall is rare. It was previously described in a few cases, but they were associated with the presence of an incisional hernia or carcinoma infiltration.
Strangulated stomach within a paraoesophageal hernia: A rare complication of laparoscopic Nissen fundoplication
Authors: Robertson J , Avjioglu E
Published: August 2010

A strangulated stomach within a paraoesophageal hernia is a rare complication following laparoscopic Nissen fundoplication. A case is presented together with a review of the clinical presentation, mechanism and diagnostic difficulties of this entity.
Typical magnetic resonance features of a haemangioblastoma, an uncommon nerve root lesion: Case report and literature review
Authors: Sawyer B , Heng R , Ferris N
Published: August 2010

Haemangioblastomas are uncommon tumours of the central nervous system. Nerve root haemangioblastomas with both intradural and extradural components are extremely rare. We present a case of a C2 nerve root haemangioblastoma in a 64‐year‐old man where the preoperative diagnosis was a spinal meningioma. An unexpectedly vascular tumour was found at initial procedure. Urgent catheter angiography was performed and the tumour was embolized prior to complete excision at a subsequent procedure.
Diffuse cavernous haemangioma of colon: Magnetic resonance imaging features. Report of two cases
Authors: Kandpal H , Sharma R , Srivastava DN , Sahni P , Vashisht S
Published: August 2010

Large bowel haemangiomas are rare but can cause significant morbidity. The clinical features are non‐specific, and misdiagnosis is very common. Non‐invasive imaging is very useful in the diagnosis and management of this condition. Magnetic resonance imaging surpasses all other imaging modalities, as it is most specific and depicts the extent of the lesion accurately. Two cases of cavernous haemangioma of the rectum are presented highlighting the MRI features.
Multi‐cystic (rete testis) supernumerary testis in polyorchidism with underlying microlithiasis: Ultrasound features
Authors: Rajbabu K , Morel JC , Thompson PM , Sidhu PS
Published: August 2010

Polyorchidism is a rare congenital anomaly, readily diagnosed on ultrasound. Testicular microlithiasis is a condition increasingly recognized and with a possible association with primary testicular malignancy. Rete testis has a variable appearance and is an unusual finding in the young patient. We describe the ultrasound appearances of the combination of polyorchidism, rete testis and microlithiasis, a combination that has not been previously reported.
Calamine lotion: Mimicking intramammary calcifications
Authors: Suen KC , Ho L , Chow KLK , Wong LLS , Leong L
Published: August 2010

Detection of microcalcifications is important in detecting early breast cancer. We present a case of screening mammogram in which calamine lotion mimics intramammary calcifications.
Popliteal artery entrapment syndrome: Non‐invasive diagnosis by MDCT and MRI
Authors: Utsunomiya D , Sawamura T
Published: August 2010

We present a case of a 19‐year‐old male patient complaining of right leg pain, which appeared after exercise and abated with rest. Computed tomography (CT) and magnetic resonance angiography (MRA) showed occlusion of right popliteal artery. Volume rendering CT image showed not only occlusion of right popliteal artery but also abnormal course of the medial head of the gastrocnemius muscle (MHG). CT and MR images of right popliteal fossa showed the abnormal anatomy that MHG coursed between popliteal artery with thrombus and popliteal vein. Popliteal artery entrapment syndrome was diagnosed non‐invasively by multidetector CT and MRI. Sectional radiological and three‐dimensional images are useful for not only depiction of the arterial changes but also identification of the abnormal anatomic structures responsible for the entrapment.
Intramural haematoma of the oesophagus presenting as an unusual complication of endotracheal intubation
Authors: Wang AY , Riordan RD , Yang N , Hiew C‐y
Published: August 2010

Intramural haematoma of the oesophagus is an uncommon and under‐recognized condition. It may mimic other causes of chest pain, haematemesis, or dysphagia, and hence pose a diagnostic challenge. We report a case of an unusual presentation of intramural haematoma of the oesophagus occurring as a presumed complication of endotracheal intubation. It was disguised as acute onset post‐operative chest pain, and resolved with conservative management. Awareness of this uncommon complication is important to allow rapid and timely diagnosis and management. We review the literature, causes and imaging features of this condition.
Editorial experience with 1 year of case reports: a case report and review of the literature
Authors: Pitman AG , Walker I
Published: August 2010

We analysed the properties of radiology case reports to create a ‘personality profile’. Methods: In total, 99 case reports accepted for publication over 1 year were classified on a number of categorical parameters. Results: The commonest reported underlying aetiology was tumour (n=40), and the commonest radiological presentation was with a mass (n=29). Classic presentations of rare conditions (33%) were as common as rare presentations of common conditions (35%). Most underlying pathologies were proven with histology. Ten reports were interventional. Conclusion: The typical case report is of a tumour presenting as a mass, and ultimately proven by histology.
Diploidized eggs reprogram adult somatic cell nuclei to pluripotency in nuclear transfer in medaka fish (Oryzias latipes)
Authors: Bubenshchikova Ekaterina , Kaftanovskaya Elena , Motosugi Nami , Fujimoto Takafumi , Arai Katsutoshi , Kinoshita Masato , Hashimoto Hisashi , Ozato Kenjiro , Wakamatsu Yuko
Published: August 2010

Reprogramming of adult somatic cell nuclei to pluripotency has been unsuccessful in non‐mammalian animals, primarily because of chromosomal aberrations in nuclear transplants, which are considered to be caused by asynchrony between the cell cycles of the recipient egg and donor nucleus. In order to normalize the chromosomal status, we used diploidized eggs by retention of second polar body release, instead of enucleated eggs, as recipients in nuclear transfer of primary culture cells from the caudal fin of adult green fluorescent protein gene (GFP) transgenic medaka fish (Oryzias latipes). We found that 2.7% of the reconstructed embryos grew into adults that expressed GFP in various tissues in the same pattern as in the donor fish. Moreover, these fish were diploid, fertile and capable of passing the marker gene to the next generation in Mendelian fashion. We hesitate to call these fish ‘clones’ because we used non‐enucleated eggs as recipients; in effect, they may be chimeras consisting of cells derived from diploid recipient nuclei and donor nuclei. In either case, fish adult somatic cell nuclei were reprogrammed to pluripotency and differentiated into a variety of cell types including germ cells via the use of diploidized recipient eggs.
Spinal cord is required for proper regeneration of the tail in Xenopus tadpoles
Authors: Taniguchi Yuka , Sugiura Takuji , Tazaki Akira , Watanabe Kenji , Mochii Makoto
Published: August 2010

Tail regeneration in urodeles is dependent on the spinal cord (SC), but it is believed that anuran larvae regenerate normal tails without the SC. To evaluate the precise role of the SC in anuran tail regeneration, we developed a simple operation method to ablate the SC completely and minimize the damage to the tadpole using Xenopus laevis. The SC‐ablated tadpole regenerated a twisted and smaller tail. These morphological abnormalities were attributed to defects in the notochord (NC), as the regenerated NC in the SC‐ablated tail was short, slim and twisted. The SC ablation never affected the early steps of the regeneration, including closure of the amputated surface with epidermis and accumulation of the NC precursor cells. The proliferation rate of the NC precursor cells, however, was reduced, and NC cell maturation was retarded in the SC‐ablated tail. These results show that the SC has an essential role in the normal tail regeneration of Xenopus larvae, especially in the proliferation and differentiation of the NC cells. Gene expression analysis and implantation of a bead soaked with growth factor showed that fibroblast growth factor‐2 and ‐10 were involved in the signaling molecules, which were expressed in the SC and stimulated growth of the NC cells.
Introduction of silencing‐inducing transgene against Fgf19 does not affect expression of Tbx5 and β3‐tubulin in the developing chicken retina
Authors: Okamoto Mayumi , Tomonari Sayuri , Naito Yuki , Saigo Kaoru , Noji Sumihare , Ui‐Tei Kumiko , Ohuchi Hideyo
Published: August 2010

Fgf19 is known to be expressed in the developing chicken eye but its functions during retinal development have remained elusive. Since Fgf19 is expressed in the dorsal portion of the optic cup, it is intriguing to know whether FGF19 is required for expression of dorso‐ventral morphogenetic genes in the eye. To clarify this, expression patterns of Tbx5 and Vax were examined in the developing eye after in ovo RNA interference targeted against Fgf19. Quantitative polymerase chain reaction (PCR) analysis showed that the short‐hairpin RNAs (shRNAs) targeted against Fgf19 could reduce its expression in the eye to less than 50% of a relative amount of mRNA, compared with contralateral or untreated control eyes. However, no obvious alteration in expression domains of Tbx5 or Vax was observed. Misexpression of Tbx5 or Tbx5‐RNAi did not alter the Fgf19 expression either. Furthermore, although Fgf19 is expressed in the central retina before neurogenesis occurs, β3‐tubulin, a marker for early retinal differentiation was still detected in the central retina after knockdown of Fgf19. Thus, knockdown of Fgf19 supports no obvious regulations between Fgf19 and Tbx5, or exhibits no phenotypes that perturb early retinal differentiation.
Neural activity‐dependent regulation of gene expression in developing and mature neurons
Authors: Abe Kentaro
Published: August 2010

Neurons can change their gene expression patterns according to the inputs they have received. This activity‐dependent gene regulation mechanism plays an important role in the formation of neural circuits during development. Further, by regulating the synaptic plasticity, this mechanism may function as an essential one for each organism to adapt flexibly to its environment. This review summarizes our current knowledge about the activity‐dependent gene regulation mechanism in neurons, focusing on the transcription factors and signaling pathways involved in this mechanism.
Transgenic technology for visualization and manipulation of the neural circuits controlling behavior in zebrafish
Authors: Okamoto Hitoshi , Sato Tomomi , Aizawa Hidenori
Published: August 2010

The vertebrate brain is innately equipped with neural circuits that make quick behavioral decisions possible. Elucidating these neural circuits, determining how their master plans are encoded in the genome, and revealing how they can be modified by postnatal experiences will facilitate our understanding of how nature and nurture interact to establish an animal's behavior. In this review, we explain how transgenic zebrafish can cast insights into the developmental mechanisms and functional roles of the neural circuits that directly and indirectly control visuomotor behavior, by taking as an example a transgenic line Tg(brn3a‐hsp70:GFP) enabling visualization of the tectobulbar and habenulo‐interpeduncular tracts. These insights emphasize the benefits of applying advanced transgenic technology in zebrafish to future research into this area.
Retrospective on reverse genetics in mice around the world and in Japan
Authors: Aizawa Shinichi
Published: August 2010

The 2007 Nobel Prize for Physiology or Medicine was awarded to Mario R. Capecchi, Martin J. Evans and Oliver Smithies for their contribution in generating mutant mice by gene targeting in embryonic stem (ES) cells. Although there are many experimental animals, it is yet only in mouse that one can genetically examine functions of genes at will. It was merely a dream in the early 1980s that genetic studies with mutants would one day become a reality in mammals. The story began with tetratocarcinoma/embryonal carcinoma cells. Now, through the successes of cloning in mammals, somatic cells such as our skin cells will shortly be transformed into ES‐like (induced pluripotent stem) cells by the proper activation of endogenous genes such as Oct4 and Sox2 with chemicals. How have times changed?
Sexual development of mouse germ cells: Nanos2 promotes the male germ cell fate by suppressing the female pathway
Authors: Saga Yumiko
Published: August 2010

Much research has been conducted in recent years to elucidate the mechanisms underlying the crucial developmental process of sex determination. It has now been shown that somatic sex is principally determined by the chromosomal sex and the molecular mechanisms involved in this process have become relatively well understood in both human and mouse. However, the pathways involved in the sex determination of the germ cells remain largely unknown except for the fact that the somatic cues surrounding these cells play a significant role. Moreover, which sexual pathway of the germ cells is induced or suppressed has long been a subject of some dispute. Recent findings indicate that the key molecule that influences this choice is retinoic acid. In addition, the Nanos protein has been shown to play a critical role in promoting male germ cell differentiation. In this review, the possible mechanisms underlying these events, which have been brought to light by recent findings, are summarized to provide a better and more precise understanding of our current knowledge of the sex determination and subsequent differentiation of germ cells.
Bridging the gap from frog research to human therapy: A tale of neural differentiation in Xenopus animal caps and human pluripotent cells
Authors: Sasai Yoshiki , Ogushi Masatoshi , Nagase Tomoko , Ando Satoshi
Published: August 2010

Over the last decade, much progress has been made toward an understanding of the mechanism of regulation of neural differentiation. In this article, following a brief overview of neural induction research, I would like to discuss the potential contribution of basic embryological research to the progress of human therapeutic development in the present and future, focusing on the medical application of in vitro differentiation of neural tissues. This kind of linkage between basic and medical research will probably be strengthened even more by the recent emergence of human induced pluripotent stem cells. Human pluripotent stem cells are powerful tools for bridging the gap from our accumulated knowledge of embryology to regenerative medicine, as well as to a wide spectrum of medical and pharmaceutical research and development. In this commentary, I describe these issues with a particular emphasis on the contributions made by Japanese scientists.
Human chorionic villous macrophages as a fetal biological shield from maternal chorionic gonadotropin
Authors: Katabuchi Hidetaka , Ohba Takashi
Published: August 2010

In addition to its most well characterized biological role in the rescue and maintenance of corpus luteum function, human chorionic gonadotropin (hCG) also stimulates the onset of fetal gonadal steroidogenesis. However, excess hCG is teratogenic to fetal gonadal tissues, and therefore hCG must be tightly regulated. Although there is an anatomical barrier between the fetal vessels and maternal blood, other mechanisms may regulate hCG levels. In the present study, we investigated whether human chorionic villous macrophages degraded maternal hCG. Isolated human macrophages incorporated and degraded hCG in a time‐dependent manner. Human placental villous macrophages and phorbol myristate acetate (PMA)‐treated THP‐1 cells expressed the gene encoding an exon 9‐deleted form of the luteinizing hormone/chorionic gonadotropin (LH/CG) receptor; expression of the full‐length receptor was not determined. While both PMA‐treated or untreated THP‐1 cells could uptake hCG into their cytoplasms, hCG degradation and excretion of its byproducts only progressed in PMA‐treated THP‐1 cells. In conclusion, hCG internalization and degradation are different processes in macrophages that protect fetal gonadogenesis from excess hCG. The exon 9‐deleted LH/CG receptor, but not the full‐length receptor, is involved in the degradation of cytoplasmic hCG by organ‐specific, dominant–negative interactions.
Role of metalloproteinases at the onset of liver development
Authors: Margagliotti Sabrina , Clotman Frédéric , Pierreux Christophe E. , Lemoine Pascale , Rousseau Guy G. , Henriet Patrick , Lemaigre Frédéric P.
Published: August 2010

At the onset of liver development, the hepatic precursor cells, namely, the hepatoblasts, derive from the ventral foregut endoderm and form a bud surrounded by a basement membrane (BM). To initiate liver growth, the hepatoblasts migrate across the BM and invade the neighboring septum transversum mesenchyme. In the present study, carried out in the mouse embryo, we searched for effectors involved in this process and we examined the role of matrix metalloproteinases (MMPs). We found expression of a broad range of MMPs, among which MMP‐2 was predominantly expressed in the septum transversum and MMP‐14 in the hepatoblasts. Using a new liver explant culture system we showed that inhibition of MMP activity represses migration of the hepatoblasts. We conclude that MMPs are required to initiate expansion of the liver during development and that our culture system provides a new model to study hepatoblast migration.
Sox17 facilitates the differentiation of mouse embryonic stem cells into primitive and definitive endoderm in vitro
Authors: Qu Xue‐Bin , Pan Jie , Zhang Cong , Huang Shu‐Yang
Published: August 2010

The Sox family of HMG (high mobility group)‐box transcription factors are highly conserved in vertebrates. Sox members are involved in various developmental processes. Among them Sox17 has been demonstrated to function as an endoderm determinant in zebrafish and Xenopus, respectively. However, little is known about the role of Sox17 in mouse embryonic stem cell (ESC) differentiation. In our research, we investigated the effect of Sox17 on mouse ESC and embryoid body (EB) differentiation. The results demonstrated that Sox17 overexpression upregulated a set of endoderm‐specific gene markers, suggesting that Sox17 overexpression induced an ESC differentiation program towards both primitive and definitive endoderm. We believe this finding brings new insights into the understanding of ESC differentiation and the organogenesis of endodermal derivatives.
Role of an expansin‐like molecule in Dictyostelium morphogenesis and regulation of its gene expression by the signal transducer and activator of transcription protein Dd‐STATa
Authors: Ogasawara Shun , Shimada Nao , Kawata Takefumi
Published: August 2010

Expansins are proteins involved in plant morphogenesis, exerting their effects on cellulose to extend cell walls. Dictyostelium is an organism that possesses expansin‐like molecules, but their functions are not known. In this study, we analyzed the expL7 (expansin‐like 7) gene, which has been identified as a putative target of Dd‐STATa, a Dictyostelium homolog of the metazoan signal transducer and activator of transcription (STAT) proteins. Promoter fragments of the expL7 were fused to a lacZ reporter and the expression patterns determined. As expected from the behavior of the endogenous expL7 gene, the expL7/lacZ fusion gene was downregulated in Dd‐STATa null slugs. In the parental strain, the expL7 promoter was activated in the anterior tip region. Mutational analysis of the promoter identified a sequence that was necessary for expression in tip cells. In addition, an activator sequence for pstAB cells was identified. These sequences act in combination with the repressor region to prevent ectopic expL7 expression in the prespore and prestalk regions of the slug and culminant. Although the expL7 null mutant showed no phenotypic change, the expL7 overexpressor showed aberrant stalk formation. These results indicate that the expansin‐like molecule is important for morphogenesis in Dictyostelium.
Kidney regeneration through nephron neogenesis in medaka
Authors: Watanabe Naoki , Kato Mitsuhiro , Suzuki Norihiko , Inoue Chikako , Fedorova Svetlana , Hashimoto Hisashi , Maruyama Shoichi , Matsuo Seiichi , Wakamatsu Yuko
Published: August 2010

Although renal regeneration is limited to repair of the proximal tubule in mammals, some bony fish are capable of renal regeneration through nephron neogenesis in the event of renal injury. We previously reported that nephron development in the medaka mesonephros is characterized by four histologically distinct stages, generally referred to as condensed mesenchyme, nephrogenic body, relatively small nephron, and the mature nephron. Developing nephrons are positive forwt1expression during the first three of these stages. In the present study, we examined the regenerative response to renal injury, artificially induced by the administration of sublethal amounts of gentamicin in adult medaka. Similar to previous reports in other animals, the renal tubular epithelium and the glomerulus of the medaka kidney exhibited severe damage after exposure to this agent. However, kidneys showed substantial recovery after gentamicin administration, and a significant number of developing nephrons appeared 14 days after gentamicin administration (P < 0.01). Similarly, the expression ofwt1in developing nephrons also indicated the early stages of nephrogenesis. These findings show that medaka has the ability to regenerate kidney through nephron neogenesis during adulthood and thatwt1is a suitable marker for detecting nephrogenesis.
Evolution and diversity in avian vocal system: An Evo‐Devo model from the morphological and behavioral perspectives
Authors: Matsunaga Eiji , Okanoya Kazuo
Published: August 2010

Birds use various vocalizations to mark their territory and attract mates. Three groups of birds (songbirds, parrots, and hummingbirds) learn their vocalizations through imitation. In the brain of such vocal learners, there is a neural network called the song system specialized for vocal learning and production. In contrast, birds such as chickens and pigeons do not have such a neural network and can only produce innate sounds. Since each avian species shows distinct, genetically inherited vocal learning abilities that are related to its morphology, the avian vocal system is a good model for studying the evolution of functional neural circuits. Nevertheless, studies on avian vocalization from an evolutionary developmental‐biological (Evo‐Devo) perspective are scant. In the present review, we summarize the results of songbird studies and our recent work that used the Evo‐Devo approach to understand the evolution of the avian vocal system.
Molecular features of thyroid hormone‐regulated skin remodeling in Xenopus laevis during metamorphosis
Authors: Suzuki Ken‐ichi , Machiyama Fumiaki , Nishino Shinsuke , Watanabe Yusuke , Kashiwagi Keiko , Kashiwagi Akihiko , Yoshizato Katsutoshi
Published: August 2010

Amphibian body skin provides an opportunity to investigate the molecular mechanism of thyroid hormone (TH)‐dependent organ remodeling during metamorphosis. Global gene expression changes in the TH‐dependent body skin remodeling were studied with microarray analysis. We identified 401 genes that were differentially expressed more than fourfold for 7 days after TH‐treatment. As expected, larval‐ and adult‐type keratin genes were significantly inactivated and activated, respectively. The expression changes of the Gene Ontology annotated genes demonstrated significant correlation with the morphological and physiological changes in body skin metamorphosis. The ‘transcription and proteolysis’ category genes were first upregulated 1 day after TH‐treatment. Subsequently, the ‘cell cycle’ category genes were activated at 3 days. The ‘defense response’ and ‘immune response’ category genes were the late TH‐response genes, which were downregulated and upregulated at 5 and 7 days, respectively. From these genes, adult‐type keratin‐c (xak‐c) gene was selected as a suitable gene to visually monitor the emergence of adult‐type epidermal cells during skin remodeling, because the gene is specifically expressed in adult epidermal basal cells. We generated enhanced green fluorescent protein (EGFP)‐transgenic Xenopus laevis driven by the promoter of xak‐c gene. The keratin promoter faithfully expressed the EGFP gene in adult‐type basal cells. Spatial and temporal EGFP‐fluorescence patterns of filial 1 (F1)‐offspring tadpoles visually demonstrated an event of sequential replacement of larval keratinocytes with the newly generated adult counterparts.
Cnidarians and the evolutionary origin of the nervous system
Authors: Watanabe Hiroshi , Fujisawa Toshitaka , Holstein Thomas W.
Published: August 2010

Cnidarians are widely regarded as one of the first organisms in animal evolution possessing a nervous system. Conventional histological and electrophysiological studies have revealed a considerable degree of complexity of the cnidarian nervous system. Thanks to expressed sequence tags and genome projects and the availability of functional assay systems in cnidarians, this simple nervous system is now genetically accessible and becomes particularly valuable for understanding the origin and evolution of the genetic control mechanisms underlying its development. In the present review, the anatomical and physiological features of the cnidarian nervous system and the interesting parallels in neurodevelopmental mechanisms between Cnidaria and Bilateria are discussed.
Inhibition of stored Ca2+ release disrupts convergence‐related cell movements in the lateral intermediate mesoderm resulting in abnormal positioning and morphology of the pronephric anlagen in intact zebrafish embryos
Authors: Lam Pui Ying , Webb Sarah E. , Leclerc Catherine , Moreau Marc , Miller Andrew L.
Published: August 2010

Ca2+ is a highly versatile intra‐ and intercellular signal that has been reported to regulate a variety of different pattern‐forming processes during early development. To investigate the potential role of Ca2+ signaling in regulating convergence‐related cell movements, and the positioning and morphology of the pronephric anlagen, we treated zebrafish embryos from 11.5 h postfertilization (hpf; i.e. just before the pronephric anlagen are morphologically distinguishable in the lateral intermediate mesoderm; LIM) to 16 hpf, with a variety of membrane permeable pharmacological reagents known to modulate [Ca2+]i. The effect of these treatments on pronephric anlagen positioning and morphology was determined in both fixed and live embryos via in situ hybridization using the pronephic‐specific probes, cdh17, pax2.1 and sim1, and confocal imaging of BODIPY FL C5‐ceramide‐labeled embryos, respectively. We report that Ca2+ released from intracellular stores via inositol 1,4,5‐trisphosphate receptors plays a significant role in the positioning and morphology of the pronephric anlagen, but does not affect the fate determination of the LIM cells that form these primordia. Our data suggest that when Ca2+ release is inhibited, the resulting effects on the pronephric anlagen are a consequence of the disruption of normal convergence‐related movements of LIM cells toward the embryonic midline.
Temporal and spatial expression patterns for the tumor suppressor Maspin and its binding partner interferon regulatory factor 6 during breast development
Authors: Bailey Caleb M. , Margaryan Naira V. , Abbott Daniel E. , Schutte Brian C. , Yang Baoli , Khalkhali‐Ellis Zhila , Hendrix Mary J. C.
Published: August 2010

Interferon regulatory factor 6 (IRF6) is a non‐canonical member of the interferon regulatory factor family of transcription factors. We recently identified IRF6 as a novel Maspin‐interacting protein in mammary epithelial cells. Maspin is a tumor suppressor in the breast and has also been implicated in mammary gland morphogenesis. To explore a possible role for IRF6 in conjunction with Maspin during mammary gland growth and differentiation, we examined the expression of IRF6 and Maspin during post‐utero mammary gland development using a combination of in vitro and in vivo approaches. The data revealed that the expression of IRF6 and Maspin is temporally and spatially regulated throughout mammary gland development, with maximal expression of both proteins occurring in fully differentiated, lactating lobuloalveolar cells. We further show that IRF6 adopts a lumenal localization pattern following complete epithelial cell polarization and present new evidence for the secretion of IRF6 into the milk. These results support the hypothesis that IRF6 and Maspin are important for mammary epithelial cell differentiation, and advance our understanding of the Maspin‐IRF6 partnership during normal mammary gland development.
Overlapped and differential expression of cAMP‐dependent kinase‐inhibitor isoforms during avian organogenesis period
Authors: Wakamatsu Yoshio
Published: August 2010

Although cAMP‐dependent kinase (PKA) has been known to regulate many biological systems, including patterning, cell differentiation and proliferation, it is not well understood how the spatial‐temporal specificity of the PKA signaling is generated. While the PKA signal activation is regulated in many ways, a direct visualization of PKA activity in situ is not possible. Thus, examinations of PKA regulators will provide indirect, but nonetheless important information to elucidate the distribution of PKA activity. In the present study, three isoforms of PKA‐inhibitor (PKI) genes were identified from avian genome, and their expression patterns were examined during the organogenesis period. PKI genes were strongly expressed in muscle, liver, and nervous system primordia, suggesting their inhibitory roles on the PKA signaling in the development of these tissues.
Generation of a second eye by embryonic transplantation of the antero‐ventral hemicephalon
Authors: Kobayashi Takuma , Yasuda Kunio , Araki Masasuke
Published: August 2010

Vertebrate ocular morphogenesis requires proper dorso‐ventral polarity within the optic vesicle, and loss of dorso‐ventral polarity results in failure of optic cup formation and domain specification, as shown by a reverse transplantation of the optic vesicle. We have shown previously that the ocular development depends not only on the signal within the antero‐ventral optic vesicle but also on the extraocular signals. In the present study, using embryonic transplantation of a discrete portion of the embryonic chick brain, we demonstrate formation of a second eye from the antero‐ventral hemicephalon when it was transplanted in the antero‐dorsal hemicephalon of the host embryo. The transplant consists of an antero‐ventral quadrant of the optic vesicle and the surrounding part of the anterior cephalon. The original dorso‐ventral polarity of the transplant was once cancelled and re‐established in accordance with that of the host embryo. Neither dorsal nor ventral cephalic halves in isolation did not develop into entire eye structures under the culture condition; the dorsal halves developed merely into the retinal pigmented epithelium and the ventral halves into the neural retina alone. The present study clearly suggests that extraocular dorsal and ventral signals counterbalance each other to specify the polarity of the optic vesicle.
Retinoic acid is a negative physiological regulator of N‐cadherin during early avian heart morphogenesis
Authors: Romeih Mahmoud , Cakstina Inese , Zile Maija H.
Published: August 2010

The vitamin A‐deficient (VAD) early avian embryo has a grossly abnormal cardiovascular system that is rescued by treating the embryo with the vitamin A‐active form, retinoic acid (RA). Here we examine the role of N‐cadherin (N‐cad) in RA‐regulated early cardiovascular morphogenesis. N‐cad mRNA and protein are expressed globally in the presomite through HH14 normal and VAD quail embryos. The expression in VAD embryos prior to HH10 is significantly higher than that in normal embryos. Functional analyses of the N‐cad overproducing VAD embryos reveal N‐cad involvement in the RA‐regulated cardiovascular development and suggest that N‐cad expression may be mediated by Msx1. We provide evidence that in the early avian embryo, endogenous RA is a negative physiological regulator of N‐cad. We hypothesize that a critical endogenous level of N‐cad is needed for normal early cardiovascular morphogenesis to occur and that this level is ensured by stage‐specific, developmentally regulated RA signaling.
Transcriptional regulation of the retinoic acid receptor in the dorsal midline epidermis in theCiona intestinalisembryo
Authors: Koyano Ryosuke , Ishida Satomi , Fujiwara Shigeki
Published: August 2010

Retinoic acid regulates the spatial pattern of gene expression mainly in the epidermis in the protochordate ascidian,Ciona intestinalis. Our previous study characterized the enhancer element responsible for the activation of the retinoic acid receptor (RAR) in the dorsal midline epidermis (DME). In the present study, detailed analysis identified two small sequence elements required for the transcriptional activation in the DME. Deletion of either one of these sequences resulted in suppression of the DME enhancer, suggesting that both sites are necessary. The nucleotide sequences of these two sites were similar to the consensus recognition sequences for the Msx and Sox transcription factors, respectively. These transcription factors are expressed in the DME lineage blastomeres (b7.9 and b7.10 blastomere pairs of bilaterally symmetrical embryos of this species) at the 64‐cell stage. Electrophoretic mobility shift assays revealed that recombinant Msxb and SoxB1 proteins specifically bound to these sequences. These results suggest that Msxb and SoxB1 synergistically activate the enhancer in the DME.
Metamorphic pitx2 expression in the left habenula correlated with lateralization of eye‐sidedness in flounder
Authors: Suzuki Tohru , Washio Youhei , Aritaki Masato , Fujinami Yuichiro , Shimizu Daisuke , Uji Susumu , Hashimoto Hisashi
Published: August 2010

The bilateral symmetry of flounder larvae changes through the process of morphogenesis to produce external asymmetry at metamorphosis. The process is characterized by the lateral migration of one eye and pigmentation at the ocular side. Migration of the left or right eye to produce either dextral or sinistral forms, respectively, is usually fixed within a species. Here we propose a mechanism for the mediation of lateralization by the nodal‐lefty‐pitx2 (NLP) pathway in flounders, in which pitx2, the final left‐right determinant of the NLP pathway, is re‐expressed in the left habenula at pre‐metamorphosis. After the initiation of left‐sided pitx2 re‐expression, the eye commences migration, when the habenulae shift their position on the ventral diencephalon rightwards in sinistral flounder (Paralichthys olivaceus) and leftwards in dextral flounder (Verasper variegatus). In addition, the right habenula increases in size relative to the left habenula in both species. Loss of pitx2 re‐expression induces randomization of eye‐sidedness, manifesting as normal, reversed or bilateral symmetry, with laterality of the structural asymmetry of habenulae being entirely inverted in reversed flounders compared with normal ones. Thus, flounder pitx2 appears to be re‐expressed in the left habenula at metamorphosis to direct eye‐sidedness by lateralizing the morphological asymmetry of the habenulae.
Chicken embryonic stem cells as a non‐mammalian embryonic stem cell model
Authors: Lavial Fabrice , Pain Bertrand
Published: August 2010

Embryonic stem cells (ESCs) were isolated in the early 1980s from mouse and in the late 1990s from primate and human. These cells present the unique property of self‐renewal and the ability to generate differentiated progeny in all embryonic lineages both in vitro and in vivo. The mESCs (mouse embryonic stem cells) can contribute to both somatic and germinal lineages once re‐injected into a recipient embryo at the blastocyst stage. In avian species, chicken embryonic stem cells (cESCs) have been isolated from the in vitro culture of early chicken blastodermal cells (cBCs) taken from stage X embryo (EG&K) These cESCs can be maintained under specific culture conditions and have been characterized on the basis of their morphology, biochemical features, in vitro differentiation potentialities and in vivo morphogenetic properties. The relationship between these cESCs and some of the chicken germ cells identified and grown under specific culture conditions are still under debate, in particular with the identification of the Cvh gene as a key factor for germ cell determination. Moreover, by cloning the avian homologue of the Oct4 mammalian gene, we have demonstrated that this gene, as well as the chicken Nanog gene, was involved in the characterization and maintenance of the chicken pluripotency. These first steps toward the understanding of pluripotency control in a non‐mammalian species opens the way for the development and characterization of putative new cell types such as chicken EpiSC and raises the question of the existence of reprogramming in avian species. These different points are discussed.