Expression of Betapapillomavirus Oncogenes Increases the Number of Keratinocytes with Stem Cell-Like Properties

Human papillomaviruses (HPV) of genus Betapapillomavirus (betaPV) are associated with nonmelanoma skin cancer development in epidermodysplasia verruciformis (EV) and immunosuppressed patients. Epidemiological and molecular studies suggest a carcinogenic activity of betaPV during early stages of cancer development. Since viral oncoproteins delay and perturb keratinocyte differentiation, they may have the capacity to either retain or confer a “stem cell-like” state on oncogene-expressing cells. The aim of this study was to determine (i) whether betaPV alters the expression of cell surface markers, such as CD44 and epithelial cell adhesion molecule (EpCAM), that have been associated with epithelial stemness, and (ii) whether this confers functional stem cell-like properties to human cutaneous keratinocytes. Fluorescence-activated cell sorter (FACS) analysis revealed an increase in the number of cells with high CD44 and EpCAM expression in keratinocyte cultures expressing HPV type 8 (HPV8) oncogenes E2, E6, and E7. Particularly through E7 expression, a distinct increase in clonogenicity and in the formation and size of tumor spheres was observed, accompanied by reduction of the epithelial differentiation marker Calgranulin B. These stem cell-like properties could be attributed to the pool of CD44^high EpCAM^high cells, which was increased within the E7 cultures of HPV5, -8, and -20. Enhanced EpCAM levels were present in organotypic skin cultures of primary keratinocytes expressing E7 of the oncogenic HPV types HPV5, -8, and -16 and in clinical samples from EV patients. In conclusion, our data show that betaPV may increase the number of stem cell-like cells present during early carcinogenesis and thus enable the persistence and accumulation of DNA damage necessary to generate malignant stem cells.     

The effect of osteoporosis on self-report sleep quality in postmenopausal women

We aimed to show the effect of osteoporosis on sleep quality in 59 postmenopausal women. The participants’ bone-mineral density levels were measured by dual-energy X-ray absorptiometry (DEXA). According to their DEXA results, participants were divided into two groups as osteoporotics and controls. The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality. Fourteen osteoporotic women (43.8%) and four controls (14.8%) were “poor” sleepers (p < 0.05). Postmeno-pausal women with osteoporosis scored greater on the “sleep latency” and “sleep duration” components of PSQI than controls. According to the findings of our study, osteoporosis is a risk factor for poor sleep quality in postmenopausal women.

     

新疆四个民族中12对遗传性状基因频率分布的研究

本文对新疆维吾尔、哈萨克、柯尔克孜、塔吉克族人群的前额发际等12对遗 传性状进行了调查,计算出各个性状的基因频率、并在4个民族之间进行了比较研究。 Abstract:Twelve characters including hair beared on forehead were investigated among Uygur,Kazak,Kirgiz,and Tajik Xinjiang province.The gene frequencies of the twelve characters were calculated and compared among the four minorities.     

Calcium/calmodulin-dependent protein kinase II of the oriental fruit fly,Bactrocera dorsalis,and its association with rapid cold hardiness

The oriental fruit fly, Bactrocera dorsalis, is a serious insect pest with diverse host range. Furthermore, its invasive and polyphagous behaviors allow this species to expand its habitats. Recent climate change and increase of international trade/transportation facilitate the species expansion from subtropical to temperate regions. Low temperature during winter appears to be the major factor limiting its expansion to temperate zones in the northern hemisphere. This study reports its remarkable ability in rapid cold-hardening (RCH) along with deep supercooling capacity. A brief exposure to 9?°C significantly enhanced cold tolerance of its larvae, pupae, and adults. RCH took 1–2?h for pupae and adults, although it took 24?h for larvae. Supercooling capacity of pupae was also enhanced by RCH treatment from ?13.4?°C to ?16.6?°C. To trace genetic factors associated with RCH, calcium/calmodulin-dependent protein kinase II (Bd-CaMKII) was identified from B. dorsalis and their expression in response to RCH treatment was analyzed. Bd-CaMKII possesses three conserved domains of kinase, calmodulin, and oligomerization. Bd-CaMKII is highly homologous to CaMKII of D. melanogaster and other tephritid flies. Expression levels of Bd-CaMKII in the larvae treated with RCH were significantly increased by approximately 5.5 folds compared to those in control larvae. In addition, expression levels of HSP70 and HSP90 were also increased in response to RCH treatment. These results along with previous studies suggest that cold-hardening of B. dorsalis is functionally associated with its supercooling capacity with increased production of cryoprotectants and HSP through regulatory activity of Bd-CaMKII.     

Gating of a G protein-sensitive mammalian Kir3.1 prokaryotic Kir channel chimera in planar lipid bilayers

Kir3 channels control heart rate and neuronal excitability through GTP-binding (G) protein and phosphoinositide signaling pathways. These channels were the first characterized effectors of the βγ subunits of G proteins. Because we currently lack structures of complexes between G proteins and Kir3 channels, their interactions leading to modulation of channel function are not well understood. The recent crystal structure of a chimera between the cytosolic domain of a mammalian Kir3.1 and the transmembrane region of a prokaryotic KirBac1.3 (Kir3.1 chimera) has provided invaluable structural insight. However, it was not known whether this chimera could form functional K(+) channels. Here, we achieved the functional reconstitution of purified Kir3.1 chimera in planar lipid bilayers. The chimera behaved like a bona fide Kir channel displaying an absolute requirement for PIP(2) and Mg(2+)-dependent inward rectification. The channel could also be blocked by external tertiapin Q. The three-dimensional reconstruction of the chimera by single particle electron microscopy revealed a structure consistent with the crystal structure. Channel activity could be stimulated by ethanol and activated G proteins. Remarkably, the presence of both activated Gα and Gβγ subunits was required for gating of the channel. These results confirm the Kir3.1 chimera as a valid structural and functional model of Kir3 channels.     

Metalloproteinase/Presenilin1 processing of ephrinB regulates EphB-induced Src phosphorylation and signaling

Bidirectional signaling triggered by interacting ephrinB receptors (EphB) and ephrinB ligands is crucial for development and function of the vascular and nervous systems. A signaling cascade triggered by this interaction involves activation of Src kinase and phosphorylation of ephrinB. The mechanism, however, by which EphB activates Src in the ephrinB-expressing cells is unknown. Here we show that EphB stimulates a metalloproteinase cleavage of ephrinB2, producing a carboxy-terminal fragment that is further processed by PS1/gamma-secretase to produce intracellular peptide ephrinB2/CTF2. This peptide binds Src and inhibits its association with inhibitory kinase Csk, allowing autophosphorylation of Src at residue tyr418. EphrinB2/CTF2-activated Src phosphorylates ephrinB2 and inhibits its processing by gamma-secretase. These data show that the PS1/gamma-secretase system controls Src activation and ephrinB phosphorylation by regulating production of Src activator ephrinB2/CTF2. Accordingly, gamma-secretase inhibitors prevented the EphB-induced sprouting of endothelial cells and the recruitment of Grb4 to ephrinB. PS1 FAD and gamma-secretase dominant-negative mutants inhibited the EphB-induced cleavage of ephrinB2 and Src autophosphorylation, raising the possibility that FAD mutants interfere with the functions of Src and ephrinB2 in the CNS.     

Chemical modification of chlorinated microbial polyesters

Chlorination of microbial polyesters poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxyoctanoate) (PHO) was carried out by passing chlorine gas through their solutions. The chlorine contents in chlorinated PHB (PHB-Cl) and chlorinated PHO (PHO-Cl) were between 5.45 and 23.81 wt % and 28.09 and 39.09 wt %, respectively. Molecular weights of the chlorinated samples were in the range of between one-half to one-fourth of the original values because of hydrolysis during the chlorination process. Thermal properties of the PHO-Cl were dramatically changed with an increase in its glass transition (T(g) = 2 degrees C) and the melting transition (T(m)). The T(g) of PHB-Cl varied from -20 to 10 degrees C, and its T(m) decreased to 148 degrees C. The chlorinated poly(3-hydroxyalkanoate)s (PHA-Cl) were converted to their corresponding quaternary ammonium salts (PHA-N(+)R(3)), sodium sulfate salts (PHA-S), and phenyl derivatives (PHA-Ph). Cross-linked polymers were also formed by a Friedel-Crafts reaction between benzene and PHA-Cl. The modified PHO derivatives were characterized by (1)H NMR and (13)C NMR spectrometry, Fourier transform infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques.     

The activation state of nitrate reductase is not always correlated with total nitrate reductase activity in leaves

The relation between nitrate reductase (NR; EC 1.6.6.1) activity, activation state and NR protein in leaves of barley (Hordeum vulgare L.) seedlings was investigated. Maximum NR activity (NRA_max) and NR protein content (Western blotting) were modified by growing plants hydroponically at low (0.3 mM) or high (10 mM) nitrate supply. In addition, plants were kept under short-day (8 h light/16 h dark) or long-day (16 h light/8 h dark) conditions in order to manipulate the concentration of nitrate stored in the leaves during the dark phase, and the concentrations of sugars and amino acids accumulated during the light phase, which are potential signalling compounds. Plants were also grown under phosphate deficiency in order to modify their glucose-6-phosphate content. In high-nitrate/long-day conditions, NRA_max and NR protein were almost constant during the whole light period. Low-nitrate/long-day plants had only about 30% of the NRA_max and NR protein of high-nitrate plants. In low-nitrate/long-day plants, NRA_max and NR protein decreased strongly during the second half of the light phase. The decrease was preceded by a strong decrease in the leaf nitrate content. Short daylength generally led to higher nitrate concentrations in leaves. Under short-day/low-nitrate conditions, NRA_max was slightly higher than under long-day conditions and remained almost constant during the day. This correlated with maintenance of higher nitrate concentrations during the short light period. The NR activation state in the light was very similar in high-nitrate and low-nitrate plants, but dark inactivation was twice as high in the high-nitrate plants. Thus, the low NRA_max in low-nitrate/long-day plants was slightly compensated by a higher activation state of NR. Such a partial compensation of a low NR_max by a higher dark activation state was not observed with phosphate-depleted plants. Total leaf concentrations of sugars, of glutamine and glutamate and of glucose-6-phosphate did not correlate with the NR activation state nor with NRA_max. Received: 24 March 1999 / Accepted: 31 May 1999