Identification of protein-binding DNA sequences in an auxin-regulated gene of soybean

The promoter region of a soybean auxin-responsive gene, GmAux28, was analyzed to identify protein-binding DNA sequences that may be involved in regulation of expression. Using DNase I footprinting and gel mobility shift assays, multiple regions of interaction, including eight major protein-binding sites, were observed in the GmAux28 gene. Two sequence motifs, TGACGACA and TCCACGTGTC, related to as-1/Hex and G-box elements, respectively, found in several plant promoters, were identified. Four distinct A/T-rich domains were identified; such A/T-rich domains appear to modulate, but not to specify, the expression of many genes. Two new sequence motifs, delta-1 (D1) and delta-4 (D4) were also identified. D1 and D4 share a very similar core sequence, TAGTxxCTGT and TAGTxCTGT, respectively. In gel mobility shift analyses, D1 and D4 elements exhibit a complex interaction of binding proteins. The GmAux22 promoter also contains D1-related elements which compete with the GmAux28 elements. Sequence comparisons have identified D1/D4-like sequences in several other auxin-responsive genes suggesting the possible importance of D1/D4 and the respective binding proteins in the regulation of expression of these genes.     

Detection of circulating tumor cells in colorectal cancer by immunobead-PCR is a sensitive prognostic marker for relapse of disease

BACKGROUND: Recurrent and metastatic carcinoma of the colorectum remains a major problem, with survival at 5 years post curative resection still only about 50%. Moreover, up to 30% of patients who present with early stage disease also relapse and die within 5 years, suggesting the presence of micrometastatic disease at diagnosis. One route of metastatic spread is via the blood stream, hence the detection of tumor cells in blood is likely to provide an important predictive tool with respect to relapse of disease. We have developed a sensitive molecular technique to identify tumor cells in blood using mutations in codon 12 of the K-ras gene as a marker. MATERIALS AND METHODS: Twenty-seven patients whose tumor carried a mutation in codon 12 of K-ras were studied for the presence of tumor cells in perioperative peripheral blood samples. Immunomagnetic beads, labeled with an epithelial-specific antibody, were used to harvest epithelial cells from blood. K-ras mutations were identified in this selected population using a polymerase chain reaction (PCR)-based analysis (immunobead-PCR). RESULTS: Circulating K-ras mutant cells were detected in 9 or 27 patients; seven of these nine patients have since died due to recurrent or metastatic disease. Mutant cells were not detected in 18 patients, and 16 or 18 have remained disease free (median follow-up: 16 months; range: 7-42 months). Kaplan-Meier analysis showed that detection of K-ras mutant cells in bloods was associated with significantly reduced disease-free survival (p = 0.0001). CONCLUSION: This study indicates that detection of circulating tumor cells perioperatively by immunobead-PCR provides a sensitive prognostic marker for recurrent and metastatic colorectal cancer.     

Importance of MHC class 1 alpha2 and alpha3 domains in the recognition of self and non-self MHC molecules

The importance of the species of different domains of class I MHC molecules in peripheral T cell recognition and positive and negative selection was evaluated in a single system. In transgenic mice expressing AAD (containing the alpha1+alpha2 domains of HLA-A2.1 and the alpha3 domain of H-2Dd), the CTL response to influenza peptide M1(58-66) in the context of the alpha1+alpha2 domains of HLA-A2.1 was as strong as the influenza-specific H-2Db-restricted response. However, this strong response was only discernible if the target cell MHC molecule also contained a murine alpha3 domain. In contrast, the response in HLA-A2.1 transgenic mice was about 30-fold weaker, and these CTL were indifferent to the origin of the target molecule alpha3 domain. Further analysis suggested that the major impact of the murine alpha3 domain of the transgene product was to enhance positive selection of a low affinity population of AAD-restricted T cells, presumably through species-specific interaction with CD8. Surprisingly, the response to non-self human class I MHC determinants was not augmented in AAD mice, indicating that the T cells selected are narrowly focused on AAD-related structures. Further analysis indicated that the alphal+alpha2 domains as well as the alpha3 domain influenced the magnitude of the response to non-self human class I MHC determinants, and this effect was mapped to alpha2. We suggest that the alpha2 domains of murine class I molecules contain conserved structural elements that augment the avidity of T cell-class I interactions, and this is particularly important in the recognition of non-self MHC molecules.     

Case management and preventive services among infants from low-income families

To determine the impact of an experimental approach to case management on use of child health clinic and immunization services, a nonequivalent control group with covariate measures design was employed in a sample of 98 infants from low-income families. The innovative pattern of care featured continuity of care; a single public health nurse (PHN) provided child health care to an infant by integrating case management and preventive services. In contrast, the customary pattern of child health care was characterized by fragmentation of services. Case management was segregated from preventive services, and multiple PHNs delivered care to an infant. As predicted, experimental-group infants (44%) were more likely to achieve adequate child health clinic services than control-group infants (8%) (p < 0.001). Moreover, the cost-effectiveness (C/E) ratio (dollar cost per effective intervention) for adequate child health clinic visits in continuous care ($523) was one-fifth of that in fragmented care ($2,900). The C/E ratio related to adequate immunization was 8% less in continuous care ($359) than in the fragmented approach ($386), although the difference in rates of adequate immunization was nonsignificant (experimental group, 64%; control group, 60%). These findings suggest that continuous PHN care with integrated case management is a more effective, cost-efficient approach to critical child preventive services than the customary, segregated case-management approach.     

The Role of Extracellular Carbonic Anhydrase in Biogeochemical Cycling: Recent Advances and Climate Change Responses

Climate change has been predicted to influence the marine phytoplankton community and its carbon acquisition strategy. Extracellular carbonic anhydrase (eCA) is a zinc metalloenzyme that catalyses the relatively slow interconversion between HCO₃⁻ and CO₂. Early results indicated that sub-nanomolar levels of eCA at the sea surface were sufficient to enhance the oceanic uptake rate of CO₂ on a global scale by 15%, an addition of 0.37 Pg C year⁻¹. Despite its central role in the marine carbon cycle, only in recent years have new analytical techniques allowed the first quantifications of eCA and its activity in the oceans. This opens up new research areas in the field of marine biogeochemistry and climate change. Light and suitable pH conditions, as well as growth stage, are crucial factors in eCA expression. Previous studies showed that phytoplankton eCA activity and concentrations are affected by environmental stressors such as ocean acidification and UV radiation as well as changing light conditions. For this reason, eCA is suggested as a biochemical indicator in biomonitoring programmes and could be used for future response prediction studies in changing oceans. This review aims to identify the current knowledge and gaps where new research efforts should be focused to better determine the potential feedback of phytoplankton via eCA in the marine carbon cycle in changing oceans.     

Characteristic Drying Curves of Cocoa Beans

ABSTRACT

The characteristic drying curves of cocoa beans are determined by using a tunnel drier where conditioned air passes a single cocoa berm suspended from an electronic balance in the test section. Weight loss, and temperatures of air, testa and nib of the cocoa bean is monitored on personal computers. The nornmalised drying rate versus the normalised moisture content is regressed by least square method to fit a new polynomial model for the penetration falling rate period and a linear model for the regular regime falling rate period. It can be concluded that there are three drying periods for cocoa beans namely the constant drying rate period, the penetration falling rate period and the regular regime falling rate period. The polynomial model estimates the penetration period quite well whereas the linear model estimates the regular regime quite well as well. There is no observable influence of relative humidity and air temperature on the characteristic drying curve of cocoa beans. However, the air velocity seems to have some influence on the curve.     

KINEMATIC VISCOSITY-TEMPERATURE CORRELATION FOR UNDEFINED PETROLEUM FRACTION OF A WIDE BOILING RANGE

A new correlation was developed to predict the effect of temperature on Kinematic Viscosity of petroleum fractions of all boiling ranges including 455^-°C. This correlation covers a wide boiling ranges of petroleum fractions. This correlation has been developed to represent the data for a wide range of temperature from 30 to 200°C. The correlation is based on experimental kinematic viscosity data for twenty TBP fractions of Arab heavy, Arab medium and Arab light and Arab extra-light crude oils. The proposed correlation has been found to fit all the experimental data consisting of 248 measurements of the kinematic viscosity with an over all average absolute deviation of 7.2% compared to 9.1% given by Amin (1994) et al. method.