Characterization of a Wnt-binding site of the WIF-domain of Wnt inhibitory factor-1

A Wnt-binding site of the WIF-domain of Wnt inhibitory factor-1 was localized by structure-guided arginine-scanning mutagenesis in combination with surface plasmon resonance assays. Our observation that substitution of some residues of WIF resulted in an increased affinity for Wnt5a, but decreased affinity for Wnt3a, suggests that these residues may define the specificity spectrum of WIF for Wnts. These results hold promise for a more specific targeting of Wnt family members with WIF variants in various forms of cancer.

Structured summary of protein interactions

WIFbinds to Wnt7a by surface plasmon resonance (View Interaction)WIFbinds to Wnt4 by surface plasmon resonance (View Interaction)WIF and Wnt3aphysically interact by competition binding (View Interaction 1, 2, 3, 4,5, 6)WIFbinds to Wnt9b by surface plasmon resonance (View Interaction)WIFbinds to Wnt5a by surface plasmon resonance (View Interaction)WIFbinds to Wnt11 by surface plasmon resonance (View Interaction)WIFbinds to Wnt3a by surface plasmon resonance (View Interaction)Wnt-5a and WIFphysically interact by competition binding (View Interaction 1,2, 3, 4, 5, 6)     

Neonatal pneumonia caused by Trichomonas vaginalis

The authors present two cases of newborn babies infected by Trichomonas vaginalis (hereafter referred to as T. vaginalis) and suffering from severe congenital breathing difficulties and needing artificial respiration. Microscopic examination of the tracheal discharge revealed characteristically moving, flagellated, pear-shaped unicellular organisms. Cultures on CPLM medium proved the presence of T. vaginalis. During pregnancy the mothers' clinical status was negative and both of them mentioned leukorrhoea of changing intensity. They were regularly involved in antenatal care. The infection caused by T. vaginalis could be detected in the two mothers later by culture procedures.     

Regulating Vav1 phosphorylation by the SHP-1 tyrosine phosphatase is a fine-tuning mechanism for the negative regulation of DISC formation and Fas-mediated cell death signaling

The actin cytoskeleton association is required for caspase 8-independent Fas/CD95 receptor internalization, a critical step for an optimal death-inducing signaling complex formation along the endocytic pathway, leading to efficient activation of the caspase cascade and, ultimately, cell death. However, the way in which this initiation phase of Fas receptor signaling is regulated is still unknown. We report herein that, in B cells, upon Fas engagement, the tyrosine phosphatase SHP-1-regulated Vav dephosphorylation, by downmodulating the Fas-ezrin-actin linkage is a fine-tune switch-off mechanism that the cell uses as a way to terminate the receptor internalization, controlling therefore the time and extent of the DISC formation and cell death.     

Automated Tracing of Horizontal Neuron Processes During Retinal Development

In the developing mammalian retina, horizontal neurons undergo a dramatic reorganization of their processes shortly after they migrate to their appropriate laminar position. This is an important process because it is now understood that the apical processes are important for establishing the regular mosaic of horizontal cells in the retina and proper reorganization during lamination is required for synaptogenesis with photoreceptors and bipolar neurons. However, this process is difficult to study because the analysis of horizontal neuron anatomy is labor intensive and time-consuming. In this paper, we present a computational method for automatically tracing the three-dimensional (3-D) dendritic structure of horizontal retinal neurons in two-photon laser scanning microscope (TPLSM) imagery. Our method is based on 3-D skeletonization and is thus able to preserve the complex structure of the dendritic arbor of these cells. We demonstrate the effectiveness of our approach by comparing our tracing results against two sets of semi-automated traces over a set of 10 horizontal neurons ranging in age from P1 to P5. We observe an average agreement level of 81% between our automated trace and the manual traces. This automated method will serve as an important starting point for further refinement and optimization.     

Aquatic bird densities in two coastal lagoon systems in Chiapas State,Mexico, a preliminary assessment

Six bodies of water in two coastal lagoon systems were investigated in Chiapas State, Mexico between July, 1990 and February, 1991. The size of water bodies ranged from 102.5 to 847.5 ha. Salinity varied seasonally being the lowest in July during the rainy season (1.0) and highest in February (35.8). The waters are hypertrophic with total phosphorus concentrations as high 900 mg m^–3.The number of bird species was the highest in February (N = 9 to 23) and the lowest in July (N = 2 to 15). The majority of birds present are resident species of Mexico but several species of northern birds were present in February (e.g. Lesser Scoup, Osprey, Peregrin Falcon).The number of birds observed in the waterbodies varied during the study period being as high as 2800 Cormorants, 2300 White Pelicans and 681 Limpkins, at a particular time, or expressed in terms of units surface area of each lagoon 8.0, 2.7 and 1.9 individuals per hectare respectively. The daily food requirements of White Pelicans at such a high density is about 4.1 kg ha^–1 d^–1.The hypertrophic state of Cerritos Lagoon allows a sufficient level of production to support such a high food requirement. Considering the limited survey time spent on the lagoons the bird population numbers are probably underestimated.     

Identification of a major T-cell epitope within VP3 amino acid residues 24 to 37 of Theiler's virus in demyelination-susceptible SJL/J mice.

Intracerebral inoculation of susceptible strains of mice with Theiler's murine encephalomyelitis virus (TMEV) results in a chronic, immunologically mediated demyelinating disease that shares many features with human multiple sclerosis. CD4+ T lymphocytes play a critical role in the pathogenesis of virus-induced demyelinating disease. We have identified a region within amino acid residues 24 to 37 of the VP3 capsid protein of TMEV (VP3(24-37)) that is recognized by T lymphocytes from the demyelination-susceptible SJL/J strain of mice. The T-cell response to VP3(24-37) represents a predominant Th-cell response against the virus from either TMEV-immunized or TMEV-infected SJL/J mice, and viral epitopes VP1(233-250), VP2(74-86), and VP3(24-37) account for most of the Th-cell response to TMEV.     

Possible role of adenylates in the engagement of the cyanideresistant pathway in nutrient-starved Catharanthus roseus Cells

In Cathuranthus roseus (L.) G. Don cells the cyanide-resistant pathway is engaged after phosphate or nitrogen starvation. Re-addition of these nutrients disengaged it again. Re-addition of phosphate leads to a transient disengagement which becomes only permanent after a second addition of phosphate. Disengagement after re-addition of nitrogen is slow: it takes 9 days before the activity has disappeared. In this system the mechanism of engagement of the cyanide-resistant pathway was studied. Addition of phosphate to phosphate-starved cells induced cell division within 24 h. The disengagement of the cyanide-resistant pathway was probably only an indirect effect of phosphate because the cellular P, content, which increased rapidly after addition, was low again before the cyanide-resistant pathway was disengaged. A better correlation was observed between high ADP and adenylate content of the cells and disengagement of the cyanide-resistant pathway. In addition it appeared that the engagement of the cyanide-resistant pathway was not the result of a limited carrier capacity of the cytochrome pathway. It is tentatively concluded that the engagement of the cyanide-resistant pathway in phosphate-starved cells was the result of a limited adenylate content. After nitrogen addition to N-starved cells, it took 5 days until the first growth occurred. Before the cyanide-resistant pathway was disengaged, its activity increased with the increased respiration rate which preceded growth. Within 72 h a higher ADP content was observed, which was still high after 10 days. The stimulation of the cytochrome pathway by uncoupler was small and more or less the same with and without added nitrogen, as long as the cyanide-resistant pathway was engaged. After disengagement the stimulation by uncoupler was significantly larger. It is suggested that the engagement during N-starvation was the result of a limited carrier capacity of the cytochrome pathway. Stimulation of the metabolism by re-addition of phosphate, nitrogen or sucrose resulted in a rapid increase in the levels of uracil nucleotides and uridine diphosphoglucose (UDPG) which are involved in sucrose metabolism.     

DNA-binding specificity of the Lon protease α-domain from Brevibacillus thermoruber WR-249

Lon protease has been well studied in many aspects; however, the DNA-binding specificity of Lon in prokaryotes has not been clearly identified. Here we examined the DNA-binding activity of Lon protease α-domains from Brevibacillus thermoruber (Bt), Bacillus subtilis (Bs), and Escherichia coli (Ec). MALDI-TOF mass spectroscopy showed that the α-domain from Bt-Lon binds to the duplex nucleotide sequence 5′-CTGTTAGCGGGC-3′ (ms1) and protected it from DNase I digestion. Surface plasmon resonance showed that the Bt-Lon α-domain binds with ms1 double-stranded DNA tighter than Bs- and Ec-Lon α-domains, whereas the Bt-Lon α-domain has dramatically lower affinity for double-stranded DNA with 0 and 50% identity to the ms1 binding sequence. Our results indicated that Bt-Lon α-domain plays a critical role with ms1 sequence in the DNA-binding specificity.