Grb2 and Nck act cooperatively to promote actin-based motility of vaccinia virus

The Wiskott-Aldrich syndrome protein family member N-WASP is a key integrator of the multiple signalling pathways that regulate actin polymerization via the Arp2/3 complex. Our previous studies have shown that N-WASP is required for the actin-based motility of vaccinia virus and is recruited via Nck and WIP. We now show that Grb2 is an additional component of the vaccinia actin tail-forming complex. Recruitment of Nck and Grb2 to viral particles requires phosphorylation of tyrosine residues 112 and 132 of A36R, the vaccinia actin tail nucleator, respectively. The presence of Grb2 on the virus is also dependent on the polyproline-rich region of N-WASP. The Grb2 pathway alone is therefore unable to nucleate actin tails, as its recruitment requires the prior recruitment of N-WASP by Nck. However, Grb2 does play an important role in actin-based motility of vaccinia, as in its absence, the mean number of actin tails per cell is reduced 2.6-fold. Thus, both Nck and Grb2 act in a cooperative manner to stabilize and/or activate the vaccinia actin-nucleating complex. We suggest that such cooperativity between "primary" and "secondary" adaptor proteins is likely to be a general feature of receptor-mediated signalling.     

Successful immunotherapy with matrix metalloproteinase-derived peptides in adjuvant arthritis depends on the timing of peptide administration

We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies.     

The role of computation in modeling evolution

Artificial life uses computers and formal systems to model and explore the dynamics of evolution. A fundamental question for A-Life concerns the role of computation in these models, and how we are to interpret computer implementations that do not have actual contact with physical systems. In this paper I will discuss how models are seen to explain and predict in philosophy of science and how these ideas apply to A-Life. I will also explore how the notion of an epistemic cut, as defined by H. Pattee, can be realized in a computational model with an artificial physical world.     

Designing Cell-Targeted Therapeutic Proteins Reveals the Interplay between Domain Connectivity and Cell Binding

The therapeutic efficacy of cytokines is often hampered by severe side effects due to their undesired binding to healthy cells. One strategy for overcoming this obstacle is to tether cytokines to antibodies or antibody fragments for targeted cell delivery. However, how to modulate the geometric configuration and relative binding affinity of the two domains for optimal activity remains an outstanding question. As a result, many antibody-cytokine complexes do not achieve the desired level of cell-targeted binding and activity. Here, we address these design issues by developing a computational model to simulate the dynamics and binding kinetics of natural and engineered fusion proteins such as antibody-cytokine complexes. To verify the model, we developed a modular system in which an antibody fragment and a cytokine are conjugated via a DNA linker that allows for programmable linker geometry and protein spatial configuration. By assembling and testing several anti-CD20 antibody fragment-interferon α complexes, we showed that varying the linker length and cytokine binding affinity controlled the magnitude of cell-targeted signaling activation in a manner that agreed with the model predictions, which were expressed as dose-signaling response curves. The simulation results also revealed that there is a range of cytokine binding affinities that would achieve optimal therapeutic efficacy. This rapid prototyping platform will facilitate the rational design of antibody-cytokine complexes for improved therapeutic outcomes.     

The Origin of the White Roman Goose

In order to avoid interference from nuclear copies of mitochondrial DNA (numts), mtDNA of the white Roman goose (domestic goose) was extracted from liver mitochondria. The mtDNA control region was amplified using a long PCR strategy and then sequenced. Neighbor-joining, maximum parsimony, and maximum-likelihood approaches were implemented using the 1,177 bp mtDNA control region sequences to compute the phylogenetic relationships of the domestic goose with other geese. The resulting identity values for the white Roman geese were 99.1% (1,166/1,177) with western graylag geese and 98.8% (1,163/1,177) with eastern graylag geese. In molecular phylogenetic trees, the white Roman goose was grouped in the graylag lineage, indicating that the white Roman goose came from the graylag goose (Anser anser). Thus, the scientific name of the white Roman goose should be Anser anser ‘White Roman.’     

Targeting the angiotensin II type 2 receptor (AT2R) in colorectal liver metastases

Background  

Blockade of the angiotensin (ANG) II type 1 receptor (AT1R) inhibits tumour growth in several cancers, including colorectal cancer (CRC) liver metastases. While AT1R blockade has been extensively studied, the potential of targeting the antagonistically acting AT2R in cancer has not been investigated. This study examined the effect of AT2R activation with the agonist CGP42112A in a mouse model of CRC liver metastases.     

Role of oviposition preference in an invasive crambid impacting two graminaceous host crops

Oviposition preference studies of the Mexican rice borer, Eoreuma loftini (Dyar), on sugarcane, Saccharum spp., and rice, Oryza sativa L., showed that drought stressed sugarcane was 1.8-fold more attractive based on egg masses/plant than well watered sugarcane. The E. loftini susceptible sugarcane cultivar LCP 85-384 was 1.6-fold more attractive than HoCP 85-845 based on numbers of eggs per egg mass. Egg masses were 9.2-fold more abundant and 2.3-fold larger on sugarcane than on rice. Rice, however, was preferred to sugarcane on a plant biomass basis. Oviposition on sugarcane occurred exclusively on dry leaf material, which increased under drought stress. Egg masses per plant increased on drought stressed sugarcane and were correlated with several foliar free amino acids essential for insect growth and development. The more resistant (based on injury) but more attractive (based on oviposition) rice cultivar XL8 had higher levels of several free amino acids than the susceptible cultivar Cocodrie. The association of host plant characteristics to oviposition preference is discussed. Projected oviposition patterns relative to sugarcane and rice production areas were estimated for Texas and Louisiana based on the availability of each host in different regions of each state. These results suggest that, where sugarcane and rice co-occur, the majority of eggs would be found on sugarcane early in the season, because of this crop's substantially greater biomass compared with rice. Abundance later in the season would also favor sugarcane; however, the abundance on rice would be greater than expected solely based on host availability, largely because of the greater preference per gram of rice plant dry weight.     

Mortality event in freshwater drum Aplodinotus grunniens from Lake Ontario, Canada, associated with viral haemorrhagic septicemia virus, type IV

A mortality event primarily affecting freshwater drum Aplodinotus grunniens was noted during April and May 2005 in the Bay of Quinte, Lake Ontario, Canada. A conservative estimate of the number of dead drum was approximately 100 metric tonnes. Large numbers of dead round goby Neogobius melanostomus were also seen, as well as a few muskellunge Esox masquinongy. In the drum, there was a consistent histological pattern of variably severe panvasculitis, a necrotising myocarditis, meningoencephalitis and a segmental enteritis. Moderate numbers of bullet-shaped viral particles consistent with a rhabdovirus were identified by transmission electron microscopy (TEM) in affected heart tissue. Following primary isolation from pooled tissues on fathead minnow (FHM) cells, a morphologically similar virus, approximately 165 x 60 nm in size, was visualised. Identification of the isolate as viral haemorrhagic septicemia virus (VHSV) was confirmed by enzyme immunoassay and by polymerase chain reaction. An appropriately sized product (468 bp) of the G-glycoprotein gene (nucleotides [nt] 340 to 807) was generated with RNA extracted from FHM cell supernatant. Analysis of a 360 nt partial glycoprotein gene sequence (nt 360 to 720) indicated a 96.4 to 97.2% nucleotide identity with known strains of North American (NA) VHSV. Analysis using Neighbour-joining distance methods assigned the isolate to the same lineage as the NA and Japanese isolates (Genogroup IV). However, there was sufficient sequence divergence from known NA VHSV isolates to suggest that this isolate may represent a distinct subgroup. The effects of ongoing mortality in freshwater drum and in multiple species during spring 2006 suggest that this newly recognised virus in the Great Lakes will have continued impact in the near future.