Global Regulator AdpA_1075 Regulates Morphological Differentiation and Ansamitocin Production in Actinosynnema pretiosum subsp. auranticum.

Actinosynnema pretiosum is a well-known producer of maytansinoid antibiotic ansamitocin P-3 (AP-3). Growth of A. pretiosum in submerged culture was characterized by the formation of complex mycelial particles strongly affecting AP-3 production. However, the genetic determinants involved in mycelial morphology are poorly understood in this genus. Herein a continuum of morphological types of a morphologically stable variant was observed during submerged cultures. Expression analysis revealed that the ssgA_6663 and ftsZ_5883 genes are involved in mycelial aggregation and entanglement. Combing morphology observation and morphology engineering, ssgA_6663 was identified to be responsible for the mycelial intertwining during liquid culture. However, down-regulation of ssgA_6663 transcription was caused by inactivation of adpA_1075, gene coding for an AdpA-like protein. Additionally, the overexpression of adpA_1075 led to an 85% increase in AP-3 production. Electrophoretic mobility shift assays (EMSA) revealed that AdpA_1075 may bind the promoter regions of asm28 gene in asm gene cluster as well as the promoter regions of ssgA_6663. These results confirm that adpA_1075 plays a positive role in AP-3 biosynthesis and morphological differentiation.

Two IFNGR1 homologues in Tetraodon nigroviridis: Origin, expression analysis and ligand-binding preference.

In the present study, the divergent properties of IFNGR1 isoforms (IFNGR1-1 and IFNGR1-2) were characterized in Tetraodon nigroviridis. Despite the structural similarities between these proteins, two T. nigroviridis IFNGR1 homologues differ from each other not only in their primary nucleotide and amino acid sequences but also in their syntenic structure. Genomic analysis demonstrates the conservation of synteny between the fish IFNGR1-2s and IFNGR1s in higher vertebrates; conversely, the IFNGR1-1 has no corresponding conservation of synteny with Gallus gallus and Homo sapiens, suggesting that the two genes were derived from two different origins. Additionally, their different sensitivities to mitogens and recombinant T. nigroviridis IFN-γs were observed. Furthermore, ligand-binding analysis strongly supported the model proposed in Danio rerio, which suggests that IFNGR1-1 is the major component of the IFN-γrel receptor complex; IFN-γ most likely binds to both IFNGR1-2 and IFNGR1-1. This study is a further step towards elucidating the teleostean IFN-γ system, which is different from that in mammals.

The value of three-dimensional computed tomographic angiography in the diagnosis and treatment of vascular lesions.

BACKGROUND: The accurate classification of vascular lesions is important because treatment and prognosis vary from type to type. Diagnoses are based on a combination of clinical symptoms using many imaging techniques, including ultrasound, magnetic resonance imaging, and three-dimensional computed tomographic angiography, which is a relatively new technique. Until now, however, few studies on the clinical use of three-dimensional computed tomographic angiography reformations in vascular lesions have been published. The authors' study was designed to evaluate the value of three-dimensional computed tomographic angiography in the diagnosis and treatment of vascular lesions. METHODS: Therapeutic plans of 16 patients with vascular lesions were made based on their three-dimensional computed tomographic angiography images. Pathologic examinations were also performed to verify the authors' diagnoses after surgery. RESULTS: Three-dimensional computed tomographic angiography accurate distinguished hemangiomas and vascular malformations, which was proven pathologically. The information aided much in therapeutic planning. All patients underwent complete treatment without complications. CONCLUSIONS: The authors' study suggests that three-dimensional computed tomographic angiography is helpful in differential diagnosis of hemangiomas and vascular malformations and provides a global overview of the lesions. Three-dimensional computed tomographic angiography aids significantly in therapeutic planning.