The absolute stereochemical description of fumonisin B1 (FB1) and presumably of its congeners is now secure. In this article I summarize studies leading to this conclusion and outline the biosynthetic and synthetic studies of FB1.

The mitotic cyclins promote cell division by binding and activating cyclin-dependent kinases (CDKs). Each cyclin has a unique pattern of subcellular localization that plays a vital role in regulating cell division. During mitosis, cyclin B1 is known to localize to centrosomes, microtubules, and chromatin. To determine the mechanisms of cyclin B1 localization in M phase, we imaged full-length an...

Plexins serve as receptors for repulsive axonal guidance molecules semaphorins. The cytoplasmic domain of the semaphorin 4D (Sema4D) receptor, Plexin-B1 has two separated Ras GTPase-activating protein (GAP)-homologous domains, C1 and C2. Recently, we reported that the Rho family small GTPase Rnd1 associates with Plexin-B1, and the Plexin-B1-Rnd1 complex stimulates GTPase activity of R-Ras, indu...

High field MRI is beneficial for chemical exchange saturation transfer (CEST) in terms of high SNR, CNR, and chemical shift dispersion. These advantages may, however, be counter-balanced by the increased transmit field inhomogeneity normally associated with high field MRI. The relatively high sensitivity of the CEST contrast to B1 inhomogeneity necessitates the development of correction methods...

Transforming growth factor-b1 (TGF-b1), a multifunctional cytokine with fibrogenic properties, has been implicated in the pathogenesis of the vascular and target organ complications of hypertension. TGF-b1 may also regulate blood pressure via stimulation of endothelin-1 and/or renin secretion. Herein we explored the hypothesis that circulating levels of TGF-b1 protein (quantified using a TGF-b1...

The B1 (CD20) molecule is a Mr 33,000 phosphoprotein on the surface of human B lymphocytes that may serve a central role in the humoral immune response by regulating B-cell proliferation and differentiation. In this report, a cDNA clone that encodes the B1 molecule was isolated and the amino acid sequence of B1 was determined. B-cell-specific cDNA clones were selected from a human tonsillar cDN...

We have examined the time course and patterns of covalent aflatoxin B1:DNA adducts produced within the ribosomal RNA gene sequences isolated from the liver nuclear DNA of aflatoxin B1-treated animals. Liver nuclear DNA was initially enriched in ribosomal DNA by cesium salt density centrifugation, and incubated under alkaline conditions to stabilize bound aflatoxin B1-DNA moieties. Alkali-treate...

Somenewtriethylammoniumsalts,namelytriethylammonium4-(cyclohexyl-amino)-4-oxobut-2-enoate(B1),triethylammonium5-(cyclohexylamino)-5-oxopentanoate(B2),triethylammonium4-(cyclohexylamino)-4-oxobutanoate(B3)weresynthesizedasacorrosioninhibitorformildsteel.Thesesaltscouldtestinonemolaritysulfuricacidatroomtemperaturefor24hoursbyusingweightoflosingmethod.Theresultsrevealedthattheefficiencyofinhibiti...

Heterogeneous nuclear ribonucleoprotein (hnRNP) B1 is a RNAbinding protein of Mr 37,000. We previously reported that hnRNP B1 was specifically overexpressed in the nuclei of human lung cancer cells, particularly in squamous cell carcinoma (E. Sueoka et al., Cancer Res., 59: 1404 –1407, 1999). We extended this study to determine whether hnRNP B1 was overexpressed in roentgenographically occult c...

Activation of cyclin B1-cyclin-dependent kinase 1 (Cdk1), triggered by a positive feedback loop at the end of G2, is the key event that initiates mitotic entry. In metaphase, anaphase-promoting complex/cyclosome-dependent destruction of cyclin B1 inactivates Cdk1 again, allowing mitotic exit and cell division. Several models describe Cdk1 activation kinetics in mitosis, but experimental data on...