Vascular systems in the magnoliaceae

Journal of Plant Research - The vascular anatomy of seven genera of Magnoliaceae:Elmerrillia, Liriodendron, Magnolia, Manglietia, Michelia, Paramichelia andTalauma, was examined. Based on the...     

Apoptosis is induced by N-myc expression in hepatocytes, a frequent event in hepadnavirus oncogenesis, and is blocked by insulin-like growth factor II.

Induction of hepatocellular carcinoma in woodchucks by woodchuck hepatitis virus is associated with the activation of N-myc gene expression, usually by viral DNA integration in cis to the N-myc locus. We have examined the consequences of N-myc up-regulation in rodent hepatic cells in culture. Mouse alpha ML hepatocytes infected with a retroviral vector overexpressing the woodchuck N-myc2 gene display a higher proliferation rate than parental alpha ML cells but are morphologically unchanged and do not form colonies in soft agar. However, they display an increased propensity to undergo apoptosis, an effect that is markedly augmented by serum deprivation. Expression of the woodchuck hepatitis virus X gene in alpha ML cells does not alter the growth phenotype of the cells and has no effect upon N-myc-dependent apoptosis. However, apoptosis in N-myc2-expressing alpha ML cells is strongly inhibited by insulin-like growth factor II (IGF II). IGF II gene expression is also strongly up-regulated during hepatic carcinogenesis in vivo in virally infected animals and has been speculated to be part of an autocrine growth-stimulatory pathway. Our results suggest that IGF II may play another role in the development of virus-induced hepatoma: the prevention of programmed cell death triggered by deregulated N-myc expression.     

Localization of DNA in the condensed interphase chromosomes of Euglena

The localization of DNA in the condensed interphase chromosomes of Euglena was determined by immunoelectron microscopy. Deposits of gold particles that coincided with the localization of DNA followed threads that corresponded to the chromatin fibers. The threads were 55–80 nm in diameter and were assumed to be supersolenoids. The localization of gold deposits on chromosomes that had been sectioned in various directions suggested that the chromatin fibers coiled around the surface of chromosomes, with a wide central axial region of the chromosomes remaining free of DNA. These findings are discussed in relation to current models of chromosomal structure.     

The kinetics of end-product inhibition of l-lactate production from xylose and glucose by Lactococcus lactis IO-1

Summary The relative contributions of lactate inhibition and the generation of sterile (undividing) cells to the low xylose utilisation rate of Lactococcus lactis IO-1 was investigated. The lactate inhibition constant of xylose grown cells was shown to be 9.3 times more than that of glucose grown cells. However, the sterile cell production rate and LDH inactivation rate of the xylose cultures were at least 10 times less than the glucose cultures. Thus, it is suggested that the slower substrate consumption rate in xylose medium is caused mainly by the large inhibition constant for the end product.     

A newCercophora with aChrysosporium-like anamorph

A new species ofCercophora, isolated from river sediment collected from Sakai River in Nagasaki Prefecture, Japan, is described and illustrated. It is distinguished from the other knwon species by the morphology of its ascomatal peridium and ascospores, and by itsChrysosporium-like anamorph.     

Individual DNA identification from ancient human remains.

Individual identification of ancient human remains is one of the most fundamental requisites for studies of paleo-population genetics, including kinship among ancient people, intra- and interpopulation structures in ancient times, and the origin of human populations. However, knowledge of these subjects has been based mainly on circumstantial archaeological evidence for kinship and intrapopulation structure and on genetic studies of modern human populations. Here we describe individual identification of ancient humans by using short-nucleotide tandem repeats and mtDNAs as genetic markers. The application of this approach to kinship analysis shows clearly the presence or absence of kinship among the ancient remains examined.     

Guest-induced conformational change of β-cyclodextrin capped with an environmentally sensitive chromophore

A capped cyclodextrin, 6-deoxy-6-(p-hydroxy-m-nitrophenacylthio)-β-cyclodextrin, was prepared in order to detect any conformational change of the host upon the guest binding. The association constant between the cyclodextrin and 1-adamantanecarboxylate, cyclohexanecarboxylate, p-methylbenzoate, 3,3-dimethylbutyrate, or 2,2-dimethylpropionate was enhanced 20, 5.3, 3.7, 2.3, or 2.0 times, respectively, by chromophore capping. The changes in the electronic, NMR, and circular dichroism spectra as well as pK_a of this cyclodextrin upon binding of the guest strongly indicate a conformational change around the chromophoric moiety of the cyclodextrin.