Influence of Herbicide Application to Soybeans on Soybean Cyst Nematode Egg Hatching

The hatching of Heterodera glycines eggs in soybean root exudates collected after postemergence application of three herbicides, and the hatching potential of H. glycines eggs from females feeding on herbicide-treated plants, were measured in vitro. Hatching in all root exudate solutions (RES) was greater than in deionized water but less than in 0.003 M ZnSO₄ solution. Filtering RES with a 0.22-μm-filter increased H. glycines hatching in RES. Application of acifluorfen, bentazon, and lactofen to foliage of soybean plants inhibited hatching of H. glycines eggs from the same plants. Hatching in RES from the different herbicide-treated soybeans was similar. Application of crop oil concentrate and non-ionic surfactant adjuvant to foliage did not affect hatching of H. glycines eggs from soybean plants.     

Properties of P-form DNA as revealed by circular dichroism

Investigations of DNA using CD spectroscopy show that the P-form is available in a wide variety of methanol–ethanol mixtures when the water content is low. Increasing the temperature or the ethanol content of a 95% methanol solution causes DNA to undergo a cooperative transition to the P-form. However, this transition cannot be reversed on cooling, or on adding methanol. Thus P-form DNA appears to be stable at high methanol concentrations, but it is usually not observed because the DNA is trapped by a kinetic barrier. P-form DNA will instantaneously assume the native B-form on addition of water, confirming earlier reports that P-form DNA is not strand separated [E. Kay (1976) Biochemistry 15 , 5241]. CD spectra extended to 190 nm show that there is no base–base interaction in the P-form. However, the P-form is extremely stable to heat denaturation in solvents which promote hydrogen bonding between the base pairs. A number of models that can account for the properties of P-form DNA are discussed.     

EBNA1 distorts oriP, the Epstein-Barr virus latent replication origin.

The Epstein-Barr virus nuclear antigen 1 (EBNA1) protein binds and activates the latent replication origin (oriP) of the Epstein-Barr virus. We have been studying EBNA1 to determine how it activates replication at oriP. Here we demonstrate that upon binding of EBNA1 to oriP, two thymine residues become reactive to potassium permanganate (KMnO4), indicating a helical distortion at these sites. The KMnO4-reactive thymines are 64 bp apart in the region of dyad symmetry of oriP. Dimethyl sulfate protection studies indicated that EBNA1 binds on the opposite face of the helix from the reactive thymines. The nature of the helical distortion induced by EBNA1 and its possible significance to the initiation of replication are discussed.     

The transmembrane glycoprotein of human immunodeficiency virus type 1 induces syncytium formation in the absence of the receptor binding glycoprotein.

To study the intracellular transport and biological properties of the human immunodeficiency virus type 1 (HIV-1) transmembrane glycoprotein (TM; gp41), we constructed a truncated envelope gene in which the majority of the coding sequences for the surface glycoprotein (SU; gp120) were deleted. Transient expression of this truncated env gene in primate cells resulted in the biosynthesis of two proteins with M(r)s of 52,000 and 41,000, respectively. Immunofluorescence studies with antibodies to the HIV-1 TM protein indicated that the intracellular and surface localization of these proteins were indistinguishable from those of the native HIV-1 gp120-gp41 complex. These results indicate that the oligosaccharide processing and cell surface transport of the HIV-1 TM protein were not dependent on the presence of the receptor binding subunit, gp120. Syncytium formation was readily detected upon expression of the deleted HIV-1 env gene into COS and CD4+ HeLa cell lines, suggesting that in the absence of gp120, the TM protein retained biological activity. This observation was confirmed by infection of primate and mouse cell lines with a recombinant vaccinia virus (vvgp41) expressing the truncated HIV-1 env gene. These results strongly suggest that (i) the two biological activities of the HIV-1 envelope glycoprotein can occur independently and (ii) the association of the two glycoprotein subunits may restrict the fusion activity of the transmembrane component to CD4+ cells.     

Early clonality and high-frequency proviral integration into the c-myc locus in AKR leukemias.

Blot hybridization of thymocyte DNA from AKR/J mice was used to detect new proviral junction fragments as markers of clonality at different stages of viral leukemogenesis and to detect DNA rearrangements at the c-myc locus due to proviral insertion. Clonal populations of thymocytes were observed in mink cell focus-forming virus-injected mice as early as 35 days postinjection, at a stage distinguishable from frank leukemia by flow cytometric analysis and transplantation bioassay. Specific proviral integrations in the c-myc locus were detected in 15% of these early clones and in up to 65% of late-developing thymomas and frank leukemias. Thus, in this system c-myc activation appears to be a common mechanism in T-cell leukemogenesis.     

Cloning and sequencing of the alkaline extracellular protease gene of Yarrowia lipolytica.

The XPR2 gene encoding an alkaline extracellular protease (AEP) from Yarrowia lipolytica was cloned, and its complete nucleotide sequence was determined. The amino acid sequence deduced from the nucleotide sequence reveals that the mature AEP consists of 297 amino acids with a relative molecular weight of 30,559. The gene codes for a putative 22-amino-acid prepeptide (signal sequence) followed by an additional 135-amino-acid propeptide containing a possible N-linked glycosylation site and two Lys-Arg peptidase-processing sites. The final Lys-Arg site occurs at the junction with the mature, extracellular form. The mature protease contains two potential glycosylation sites. AEP is a member of the subtilisin family of serine proteases, with 42.6% homology to the fungal proteinase K. The functional promoter is more than 700 base pairs long, allowing for the observed complex regulation of this gene. The 5' and 3' flanking regions of the XPR2 gene have structural features in common with other yeast genes.     

Rap1 maintains adhesion between cells to affect Egfr signaling and planar cell polarity in Drosophila

The small GTPase Rap1 affects cell adhesion and cell motility in numerous developmental contexts. Loss of Rap1 in the Drosophila wing epithelium disrupts adherens junction localization, causing mutant cells to disperse, and dramatically alters epithelial cell shape. While the adhesive consequences of Rap1 inactivation have been well described in this system, the effects on cell signaling, cell fate specification, and tissue differentiation are not known. Here we demonstrate that Egfr-dependent cell types are lost from Rap1 mutant tissue as an indirect consequence of DE-cadherin mislocalization. Cells lacking Rap1 in the developing wing and eye are capable of responding to an Egfr signal, indicating that Rap1 is not required for Egfr/Ras/MAPK signal transduction. Instead, Rap1 regulates adhesive contacts necessary for maintenance of Egfr signaling between cells, and differentiation of wing veins and photoreceptors. Rap1 is also necessary for planar cell polarity in these tissues. Wing hair alignment and ommatidial rotation, functional readouts of planar cell polarity in the wing and eye respectively, are both affected in Rap1 mutant tissue. Finally, we show that Rap1 acts through the effector Canoe to regulate these developmental processes.     

Isotopic evidence of dietary variations and weaning practices in the Gaya cemetery at Yeanri,Gimhae, South Korea

Stable carbon and nitrogen isotope analyses were conducted to investigate dietary variation in human skeletons (n = 109) from the Gaya cemetery at Yeanri located near Gimhae City, South Korea. The cemetery contained three distinct grave types dating to 4th–7th century AD. The main purposes of this research were to reconstruct palaeodiet in the Gaya population and to explore correlations between stable isotope compositions and burial types, inferred age, and sex of these individuals. The isotopic data indicate that the people at Yeanri consumed a predominantly C₃‐based terrestrial diet supplemented with freshwater and/or marine resources. The comparison of isotopic results reveals significant differences in δ¹³C values among three adult burial types (wood‐cist coffin: ?18.5 ± 0.5‰, stone‐cist coffin: ?18.1 ± 0.6‰, mausoleum: ?17.8 ± 0.9‰). Males in wood‐cist and stone‐cist coffins have relatively more elevated mean δ¹³C and δ¹⁵N values than females. The isotopic ratios from the two adult age groups (21–40 years and 40–60 years) indicate that there was no significant dietary change in individuals with age. The isotope data from the infants and children suggest the weaning was a gradual process that was completed between 3 and 4 years of age in the Gaya population. This evidence indicates that the dietary variations within the cemetery reflect social status, sex, and childhood consumption patterns. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Nuclear translocation of EndoG at the initiation of disuse muscle atrophy and apoptosis is specific to myonuclei

Skeletal muscle atrophy is associated with an increase in apoptosis, and we showed previously that endonuclease G (EndoG) is localized to nuclei following unloading. The goal of this study was to determine whether the onset of apoptosis in response to disuse was consistent with the hypothesis that EndoG is involved in myofiber nuclear loss. Atrophy was induced by hindlimb suspension for 12 h or 1, 2, 4 and 7 days in 6-mo-old rats. Soleus myofiber cross-sectional area decreased significantly by 2 days, whereas muscle mass and muscle-to-body mass ratio decreased by 4 and 7 days, respectively. By contrast, a significant increase in apoptosis, evidenced by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive nuclei, occurred as early as 12 h after suspension, preceding the elevation in muscle atrophy F-box gene expression. The early increase in apoptosis appeared to be specific to myofiber nuclei, whereas TUNEL-positive interstitial cells did not become significantly elevated until 2 days after suspension. Furthermore, TUNEL-positive myofiber nuclei colocalized with EndoG as early as 12 h after suspension, and no such localization was observed in interstitial cells. Although no significant change in total activated caspase-3, -7, or -12 protein abundance was apparent, activated caspase-3 was expressed in interstitial cells undergoing apoptosis, some of which were endothelial cells. These data indicate that apoptosis is an early, and therefore possibly causative, event in the process of muscle atrophy, and that EndoG nuclear translocation is specific for myofiber nuclear apoptosis, whereas interstitial cells may undergo apoptosis via a more classical, caspase-dependent pathway.