A straightforward method for extracting aculeate arthropod venoms by centrifugation is described, based on adapting a glass insert containing a piece of metal mesh or glass wool into a centrifuge ...tube. Venom apparatuses are centrifuged for 30 s intervals at ≈2000–6000 g, with samples being dislodged between cycles. Venom from fire ants, honeybees, and a social wasp were extracted within minutes. The method is suited for small-scale bioassays and allows for faithful descriptions of unmodified toxin cocktails.
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•A method for milking crude venom from tissues by trivial centrifugation is described.•The new method enabled the discovery of new molecules in the venom of fire ants.•Pilot tests with other species illustrate immediate potential for novel insights into venom composition.•Due to its simplicity the method can be easily adapted to other arthropods.
Canopy temperature (Tc) measurements with infrared thermometry have been widely used to assess plant water status. Here, we evaluated Tc and its controlling factors in a primary tropical rainforest ...(TRF), subtropical evergreen broad-leaved forest (STF) and valley savanna forest (SAF) in southwestern China. We found differences between Tc and air temperature (Ta) of as much as 2.2 °C between the dry and wet seasons in the TRF. However, the canopy-to-air temperature difference (Tc-Ta) was only 0.3 °C between the dry and wet seasons in the STF. Solar radiation (SR) was the dominant factor in Tc-Ta variations during the dry and wet seasons at the three sites. The increased heating in the canopy leaves was likely the result of low stomatal conductance leading to low transpiration cooling. Changes in Tc-Ta in the TRF were highly sensitive to the degree of stomatal closure. The change in Tc-Ta was controlled by the climate, but inherent plant traits, such as stomatal conductance, also played an important controlling role.
Magnetization transfer imaging is an MRI technique that provides quantitative information about in vivo tissue integrity, including myelin and axonal content, and is expressed as the magnetization ...transfer ratio (MTR). The optic neuritis lesion can model the MS lesion in vivo and permits use of non-invasive markers of optic nerve myelination (visual evoked potential VEP latency) and retinal neuroaxonal loss (optical coherence tomography OCT) to provide further information about the in vivo substrates of optic nerve MTR. Twenty-five patients with optic neuritis were studied using an optic nerve MTR sequence, quantitative visual function testing, VEPs and OCT, along with 15 controls. MTR was reduced in affected nerves compared to both clinically unaffected nerves from patients and control nerves (P < 0.001). Whole-nerve MTR correlated modestly with central-field VEP latency but more strongly when lesion-only MTR was measured, when a modest correlation with whole-field VEP latency emerged. OCT-quantified retinal neuroaxonal loss also correlated with MTR. In conclusion, markers of optic nerve myelination and axonal loss both correlate with optic nerve MTR. Because axonal loss following optic neuritis also results in myelin loss, the relative contributions of the two pathological conditions to the MTR measures cannot be estimated from this study. Multiple Sclerosis 2007; 13: 875—879. http://msj.sagepub.com
Our prior studies show that multiple myeloma (MM) cell lines and patient cells express high-affinity vascular endothelial growth factor (VEGF) receptor (VEGFR) Flt-1 but not Flk-1/KDR. Moreover, ...these studies have shown that VEGF induces proliferation and migration of MM cells, and we have begun to delineate the signaling cascades mediating those sequelae. In this study, we examined the activity of PTK787/ZK 222584 (PTK787), a molecule designed to bind specifically to the tyrosine kinase domain of VEGFR and inhibit angiogenesis. We show that PTK787 acts both directly on MM cells and in the bone marrow microenvironment. Specifically, PTK787 (1-5 micro M) inhibits proliferation of MM cells by 50%, as assayed by (3)Hthymidine uptake. This effect of PTK787 is dose dependent in both MM cell lines and patient cells that are both sensitive and resistant to conventional therapy. PTK787 enhances the inhibitory effect of dexamethasone on growth of MM cells and can overcome the protective effect of interleukin 6 (IL-6) against dexamethasone-induced apoptosis. PTK787 (1 micro M) also blocks VEGF-induced migration of MM cells across an extracellular matrix. Importantly, PTK787 also inhibits the increased MM cell proliferation and increased IL-6 and VEGF secretion in cultures of MM cells adherent to bone marrow stem cells. These findings therefore demonstrate that PTK787 both acts directly on MM cells and inhibits paracrine IL-6-mediated MM cell growth in the bone marrow milieu. The demonstrated anti-MM activity of PTK787, coupled with its antiangiogenic effects, provides the framework for clinical trials of this agent to overcome drug resistance and improve outcome in MM.
P53 controls the cell cycle arrest and cell apoptosis through interaction with the downstream genes and their signal pathways. To stimulate the investigation into the complicated responses of p53 ...under the circumstance of ion radiation (IR) in the cellular level, a dynamic model for the p53 stress response networks is proposed. The model can be successfully used to simulate the dynamic processes of generating the double-strand breaks (DSBs) and their repairing, ataxia telangiectasia mutated (ATM) activation, as well as the oscillations occurring in the p53-MDM2 feedback loop.
A proof of concept for using paper test as a suitable method in the production of monoclonal antibodies (MAbs) is reported. The paper test which detects antibodies against porcine circovirus type 2 ...(PCV2) using colloidal gold-labelled capsid protein as the antigen probe was applied exclusively in the screening of anti-PCV2 MAbs. It allowed the detection of 118 single cell clones within 30 min using naked eyes. MAbs with specific binding to authentic epitopes on the virus were selected using a blocking strategy in which the antibody was pre-incubated with PCV2 viral sample before applying to the test paper. Five hybridomas secreting MAbs against the capsid protein were obtained, with only three of them capable of binding to PCV2. The results were validated and confirmed using enzyme-linked immunosorbent assay and immunofluorescence assay. The paper test is simple, rapid, and independent on professional technicians and proves to be an excellent approach for the screening of MAbs against specific targets.
► An abnormal electrical transport behavior was observed in polycrystalline TbFeO3. ► The abnormal electrical behavior is related to the spin-reorientation transition. ► Such magneto-electrical ...coupling phenomenon is attributed to superexchange effect.
Perovskite-type polycrystalline TbFeO3 ceramic was synthesized by a conventional solid state reaction method. Crystal structure, optical properties and electrical properties were investigated. The temperature dependent X-ray diffraction results show that the sample crystallized in an orthorhombic perovskite structure with space group Pbnm and the crystal structure had no obvious change with the decrease of temperature down to 200K. The electrical characterization result show an interesting electrical transition in the temperature range of 200–300K, such abnormal electrical transition is considered to be related to the spin-reorientation behavior happened in the temperature range mentioned above. The magneto-electric coupling phenomenon in TbFeO3 is mainly due to superexchange interaction, which can be significantly affected by spin direction.
Magnetic transport behaviors of a zigzag-edge trigonal graphene (ZTG) constructed as a nanodevice with zigzag graphene nanoribbon (ZGNR) electrodes are investigated, and various magnetic ...configurations are considered. It is found that excellent magnetic device natures, such as the perfect (100%) spin polarization in a large bias region, spin-resolved rectification ratios approaching 10 super(5), and the giant magnetoresistance effect up to 10 super(15)%, can be achieved, which is indeed an extremely high value as compared with previously reported theoretical one, ~10 super(7)%, for complete ZGNR-based magnetic devices and experimental ones, ~10 super(4)%, for the MgO tunnel junction. This can be attributed to unique transmission features due to the strong modulating ability of ZTG for the magnetic transport. These results suggest that the ZTG might possess some advantages in nature for developing magnetic devices.
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