Detection of human antigens on the surface of mouse cells transformed by chromosome transfer]

Mouse embryo cells, transformed in vitro by the transfer of chromosomes from HeLa human tumour cells, express a surface antigen (s) also found on HeLa cells. This antigen(s), which has been detected both by indirect immunofluoresence and by a 125I-protein A binding assay, is not an antigen(s) shared by both Human and Mouse cells.     

Aligning Academic Activities: Implications for Teaching and Research in a New Zealand Institute of Technology

A problem situation that is at the heart of a New Zealand higher education institute applying for university status is meeting the requirement for sufficient academic staff with postgraduate qualifications. For this particular New Zealand higher education institute that was originally a teaching institution offering only sub-degree qualifications, the move to firstly offering degrees and secondly seeking university status has meant that employment conditions have shifted for many academics. In order to explore the multiple world views on the impact to the whole system of a significant number of staff upgrading qualifications whilst engaged in full-time teaching at the same time, views were sought from senior executives, heads of schools, human resource personnel and staff engaged in their own postgraduate study. Multiple conceptual models have been utilised to gain an understanding of this problem situation: Soft Systems Methodology (Checkland and Scholes, 1990, 1999) in both its original and its current form; complexity theory (McKenna, 1999; Merry, 1995; Stacey, 1996) and context-dependent cluster model (CDCM) (Fielden and London, 2001). These multiple conceptual models have all contributed to providing a basis upon which to compare multiple-perceived worlds with appropriate conceptual models upon which to base a future action plan.Outcomes discussed are both positive and negative factors including: recognition, time, stress, employment contracts, senior staff expectations, family, collegial and institutional support and the integration of own study with teaching practice and content. Implications for alignment across institutional organisational levels and also for higher education outside of the university sector are also discussed.     

Independent modulation of collagen fibrillogenesis by decorin and lumican

The leucine-rich proteoglycans (also known as "small, leucine-rich proteoglycans," or SLRPs) lumican and decorin are thought to be involved in the regulation of collagen fibril assembly. Preparation of these proteoglycans in chemical amounts without exposure to denaturants has recently been achieved by infecting HT-1080 cells with vaccinia virus that contains an expression cassette for these molecules. Addition of lumican and decorin to a collagen fibrillogenesis assay based on turbidity demonstrated that lumican accelerated initial fibril formation while decorin retarded initial fibril formation. At the end of fibrillogenesis, both proteoglycans resulted in an overall reduced turbidity, suggesting that fibril diameter was lower. The presence of both proteoglycans had a synergistic effect, retarding fibril formation to a greater degree than either proteoglycan individually. Competitive binding studies showed that lumican did not compete for decorin-binding sites on collagen fibrils. Both proteoglycans increased the stability of fibrils to thermal denaturation to approximately the same degree. These studies show that lumican does not compete for decorin-binding sites on collagen, that decorin and lumican modulate collagen fibrillogenesis, and that, in the process, they also enhance collagen fibril stability.     

FKF1 is essential for photoperiodic-specific light signalling in Arabidopsis

Adaptation to seasonal change is a crucial component of an organism's survival strategy. To monitor seasonal variation, organisms have developed the capacity to measure day length (photoperiodism). Day-length assessment involves the photoperiodic control of flowering in Arabidopsis thaliana, whereby the coincidence of light and high expression of CONSTANS (CO) induces the expression of FLOWERING LOCUS T (FT), leading to flowering in long-day conditions. Although controlling CO expression is clearly a key step in day-length discrimination, the mechanism that generates day-length-dependent CO expression remains unknown. Here we show that the clock-controlled FLAVIN-BINDING, KELCH REPEAT, F-BOX (FKF1) protein has an essential role in generating the diurnal CO peak and that this function is dependent on light. We show that a recombinant FKF1 LIGHT, OXYGEN OR VOLTAGE (LOV) domain binds the chromophore flavin mononucleotide and undergoes light-induced photochemistry, indicating that FKF1 may function as a photoperiodic blue-light receptor. It is likely that the circadian control of FKF1 expression and the light regulation of FKF1 function coincide to control the daytime CO waveform precisely, which in turn is crucial for day-length discrimination by Arabidopsis.     

Mutation of protein kinase A causes heterochronic development of Dictyostelium.

In heterochronic mutants the relative timing of developmental events is altered compared with the wild type. This generally results in a disordered embryo, though heterochronic mutations may also be an important source of evolutionary variation. In the rapidly developing (rde) mutants of Dictyostelium, stalk and spore cells differentiate before morphogenesis is complete. We have traced the lesion in one class of these mutants to the regulatory subunit of cyclic AMP-dependent protein kinase (pk-A). Inactivation of this protein results in the unrestrained activity of the catalytic subunit, so prematurely triggering terminal cell differentiation.