Prevalence of Kaposi’s sarcoma-associated herpesvirus in Uygur and Han populations from the Urumqi and Kashgar regions of Xinjiang,China

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the infectious etiologic agent associated with Kaposi’s sarcoma (KS), primary effusion lymphoma, and multicentric Castleman disease. It has been shown that high KSHV prevalence and high incidence of both classic KS and AIDSassociated KS are found mostly among people of Uygur ethnicity in Xinjiang, while people of Han ethnicity in Xinjiang have a higher KSHV seroprevalence than those of other Han populations in mainland China. However, it is still unclear why there is such geographical and population variation in KSHV distribution in China. In this work, we focused on the populations in the Kashgar region and Urumqi area, where a total of 1294 research subjects were randomly selected to investigate the potential correlation between KSHV prevalence and different ethnicities in endemic areas of Xinjiang, and to determine risk factors that may affect KSHV infection rates or KS incidence. We identified a high seroprevalence of KSHV and high peripheral blood DNA infection in the general Uygur and Han populations in both Urumqi and Kashgar regions of Xinjiang, and determined that advancing age, low education level, and stationary population status affect KSHV infection rates. Further, KSHV-positive Uygur participants were shown to have higher prevalence of neutralizing antibodies and neutralizing antibody titers than KSHV-positive Han participants.

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High Throughput SSR Multiplex Kits (12 plex) for Euphrates’ Poplar,Populus euphratica (Salicaceae)

Multiplex PCR of microsatellite is a cost effective and high throughput technique of genotyping. We developed a new 12 plex PCR kit for Populus euphratica, the only tree species in desert area ranging from Western China to Mediterranean coast. Three primers were designed for the expressed sequence tags (ESTs) sequences from the NCBI database and the other nine primers were designed based on the EST sequences of Peuphratica obtained by Solexa. The multiplex kit was tested by 96 samples from three natural populations. The results showed sufficient amplification stability and high polymorphism. All the 12 loci used in this kit showed a high transferability (79%) in other seven species from five sections of the genus. The new 12 plex kit combined with the two eight multiplex kits we had developed in previous studies, should be useful to reveal the genetic mechanism and evolution history of the Peuphratica and related species. During the research, we found that primers selection, amplification efficiency, null allele detection are the essential parts of the multiplex kit development.     

Crystal structure of Natratoxin, a novel snake secreted phospholipaseA2 neurotoxin from Naja atra venom inhibiting A-type K+ currents

Snake secreted phospholipasesA2 (sPLA2s) are widely used as pharmacological tools to investigate their role in diverse pathophysiological processes. Some members of snake venom sPLA2s have been found to block voltage-activated K(+) channels (K(v) channels). However, most studies involved in their effects on ion channels were indirectly performed on motor nerve terminals while few studies were directly done on native neurons. Here, a novel snake sPLA2 peptide neurotoxin, Natratoxin, composed of 119 amino acid residues and purified from Naja atra venom was reported. It was characterized using whole-cell patch-clamp in acutely dissociated rat dorsal root ganglion (DRG) neurons. It was found to effectively inhibit A-type K(+) currents and cause alterations of channel gating characters, such as the shifts of steady-state activation and inactivation curves to hyperpolarization direction and changes of V(1/2) and slope factor. Therefore, Natratoxin was suggested to be a gating modifier of K(v) channel. In addition, this inhibitory effect was found to be independent of its enzymatic activity. These results suggested that the toxin enacted its inhibitory effect by binding to K(v) channel. To further elucidate the structural basis for this electrophysiological phenomenon, we determined the crystal structure of Natratoxin at 2.2 A resolution by molecular replacement method and refined to an R-factor of 0.190. The observed overall fold has a different structural organization from other K(+) channel inhibitors in animal toxins. Compared with other K(v) channel inhibitors, a similar putative functional surface in its C-terminal was revealed to contribute to protein-protein interaction in such a blocking effect. Our results demonstrated that the spatial distribution of key amino acid residues matters most in the recognition of this toxin towards its channel target rather than its type of fold.     

A mild, efficient, and selective procedure for transprotection of acetonides to acetates catalyzed with HClO4-SiO2

The transformation of acetonides into acetates is frequently required in synthetic chemistry. An efficient procedure for direct conversion of acetonides into acetates in the presence of HClO₄-SiO₂ under mild conditions was developed. The acetonides of primary hydroxy groups are directly converted to diacetates, and the anomeric acetonides of furanosides are stereoselectively transformed into the corresponding acetyl β-d-furanosides with a 2-acetoxyisopropyl group.     

Plasma membrane permeabilization by 60- and 600-ns electric pulses is determined by the absorbed dose

We explored how the effect of plasma membrane permeabilization by nanosecond-duration electric pulses (nsEP) depends on the physical characteristics of exposure. The resting membrane resistance (R(m)) and membrane potential (MP) were measured in cultured GH3 and CHO cells by conventional whole-cell patch-clamp technique. Intact cells were exposed to a single nsEP (60 or 600 ns duration, 0-22 kV/cm), followed by patch-clamp measurements after a 2-3 min delay. Consistent with earlier findings, nsEP caused long-lasting R(m) decrease, accompanied by the loss of MP. The threshold for these effects was about 6 kV/cm for 60 ns pulses, and about 1 kV/cm for 600 ns pulses. Further analysis established that it was neither pulse duration nor the E-field amplitude per se, but the absorbed dose that determined the magnitude of the biological effect. In other words, exposure to nsEP at either pulse duration caused equal effects if the absorbed doses were equal. The threshold absorbed dose to produce plasma membrane effects in either GH3 or CHO cells at either pulse duration was found to be at or below 10 mJ/g. Despite being determined by the dose, the nsEP effect clearly is not thermal, as the maximum heating at the threshold dose is less than 0.01 degrees C. The use of the absorbed dose as a universal exposure metric may help to compare and quantify nsEP sensitivity of different cell types and of cells in different physiological conditions. The absorbed dose may also prove to be a more useful metric than the incident E-field in determining safety limits for high peak, low average power EMF emissions.     

The C1 and C2 domains target human type 6 adenylyl cyclase to lipid rafts and caveolae

Previous data has shown that adenylyl cyclase type 6 (AC6) is expressed principally in lipid rafts or caveolae of cardiac myocytes and other cell types while certain other isoforms of AC are excluded from these microdomains. The mechanism by which AC6 is localized to lipid rafts or caveolae is unknown. In this study, we show AC6 is localized in lipid rafts of COS-7 cells (expressing caveolin-1) and in HEK-293 cells or cardiac fibroblasts isolated from caveolin-1 knock-out mice (both of which lack prototypical caveolins). To determine the region of AC6 that confers raft localization, we independently expressed each of the major intracellular domains, the N-terminus, C1 and C2 domains, and examined their localization with various approaches. The N-terminus did not associate with lipid rafts or caveolae of either COS-7 or HEK-293 cells nor did it immunoprecipitate with caveolin-1 when expressed in COS-7 cells. By contrast, the C1 and C2 domains each associated with lipid rafts to varying degrees and were present in caveolin-1 immunoprecipitates. There were no differences in the pattern of localization of either the C1 or C2 domains between COS-7 and HEK-293 cells. Further dissection of the C1 domain into four individual proteins indicated that the N-terminal half of this domain is responsible for its raft localization. To probe for a role of a putative palmitoylation motif in the C-terminal portion of the C2 domain, we expressed various truncated forms of AC6 lacking most or all of the C-terminal 41 amino acids. These truncated AC6 proteins were not altered in terms of their localization in lipid rafts or their catalytic activity, implying that this C-terminal region is not required for lipid raft targeting of AC6. We conclude that while the C1 domain may be most important, both the C1 and C2 domains of AC6 play a role in targeting AC6 to lipid rafts.     

Osteoporosis: A neuroskeletal disease?

Osteoporosis is caused by a failure of bone homeostasis, but the precise molecular mechanisms controlling bone homeostasis are largely unknown. Increasing evidence that neurons and neurotransmitters are intimately involved in bone remodelling has shed light on a novel regulatory mechanism for bone homeostasis. Namely, like all other homeostatic functions, bone remodelling is under the control of the hypothalamus, and osteoporosis is considered to be a neuroskeletal disease.