Light responses in Photoperiodism in Arabidopsis thaliana

ADO1: An Arabidopsis blue light photoreceptor We have reported the characterization of an Arabidopsis gene encoding the ADAGIO 1 (ADO1) protein (Jarillo et al., 2001a). ADO1 contains a LOV domain, similar to WHITE COLLAR 1 (WC1), a photoreceptor for entrainment of Neurospora circadian rhythms (Froehlich et al., 2002), as well as PHOT1 and PHOT2, the blue light photoreceptors for phototropism (Briggs et al., 2001; Christie et al., 1998; Jarillo et al., 2001b; Kinoshita et al., 2001). Loss of function ado1 mutants show an unusually long periodicity for their free running circadian rhythm (Jarillo et al., 2001a). This observation holds for plants grown under white light as well as blue light and surprisingly, plants grown under red light also show altered circadian properties. The similarity of the LOV domain of ADO1 to those of PHOT1, PHOT2 and WC1 (known flavoprotein photoreceptors) as well as the genetic and molecular properties of ADO1, indicate that ADO1 is likely a new class of blue light photoreceptor. Indeed, the LOV domain of the related FKF1/ADO3 has been shown to bind FMN, and exhibit the in vitro photochemistry characteristic of PHOT1 (Imaizumi et al., 2003). Furthermore, ZTL/ADO1 has been shown to participate in the circadian and proteasome mediated degradation of the Arabidopsis clock protein, TOC1 (Mas et al., 2003). We also showed that the ado1 mutation selectively confers hypersensitivity to red light — when grown under red light (but not blue light) the ado1 mutant possesses an unusually short hypocotyl. This red light hypersensivity is even more severe in a triple ado1 ado2 ado3 mutant — ADO2 and ADO3 being the two other members of this ADAGIO gene family. This finding of a mutant phenotype under red light is somewhat unexpected for a protein thought to function as a photoreceptor for blue light. We have pursued our studies of ADO1 by preparing a mutant gene for which we have altered the codon for the cysteine residue conserved in all LOV domains. It is this cysteine residue that forms a covalent adduct with the bound flavin in the photocycle of PHOT1 and FKF1. In the mutant ADO1 this cysteine is replaced by an alanine. We argue that if ADO1 functions as a photoreceptor in a similar fashion to PHOT1, then this mutant ADO1 should not be able to rescue the altered circadian phenotype of ado1 mutant plants. We find under white light, that indeed this is the case. Experiments underway are aimed at determining if the altered circadian phenotype under blue and red light are similarly unable to be rescued by the mutant gene, and we are performing similar experiments under red light with respect to the defect in hypocotyl elongation. The results from these experiments will likely support the hypothesis that ADO1 functions as a blue light photoreceptor, and they will address the question concerning whether or not the altered properties of the ado1 mutant under red light are also a reflection of this photoreceptor function. References. Briggs, W. R., Beck, C. F., Cashmore, A. R., Christie, J. M., Hughes, J., Jarillo, J. A., Kagawa, T., Kanegae, H., Liscum, E., Nagatani, A., et al. (2001). The phototropin family of photoreceptors. Plant Cell 13, 993-997. Christie, J. M., Reymond, P., Powell, G. K., Bernasconi, P., Raibekas, A. A., Liscum, E., and Briggs, W. R. (1998). Arabidopsis NPH1: A flavoprotein with the properties of a photoreceptor for phototropism. Science 282, 1698-1701. Froehlich, A. C., Liu, Y., Loros, J. J., and Dunlap, J. C. (2002). White Collar-1, a circadian blue light photoreceptor, binding to the frequency promoter. Science 297, 815-819. Imaizumi, T., Tran, H. G., Swartz, T. E., Briggs, W. R., and Kay, S. A. (2003). FKF1 is essential for photoperiodic-specific light signalling in Arabidopsis. Nature 426, 302-306. Jarillo, J. A., Capel, J., Tang, R.-H., Yang, H.-Q., Alonso, J. M., Ecker, J. R., and Cashmore, A. R. (2001a). An Arabidopsis circadian clock component interacts with both CRY1 and phyB. Nature 410, 487-490. Jarillo, J. A., Gabrys, H., Capel, J., Alonso, J. M., Ecker, J. R., and Cashmore, A. R. (2001b). Phototropin-related NPL1 controls chloroplast relocation induced by blue light. Nature 410, 952-954. Kinoshita, T., Doi, M., Suetsugu, N., Kagawa, T., Wada, M., and Shimazaki Ki, K. (2001). phot1 and phot2 mediate blue light regulation of stomatal opening. Nature 414, 656-660. Mas, P., Kim, W. Y., Somers, D. E., and Kay, S. A. (2003). Targeted degradation of TOC1 by ZTL modulates circadian function in Arabidopsis thaliana. Nature 426, 567-570

Sequence of the fourth and fifth Photosystem II Type I chlorophyll a/b -binding protein genes of Arabidopsis thaliana and evidence for the presence of a full complement of the extended CAB gene family

A second locus ( Lhb1B ) encoding Photosystem II Type I chlorophyll a/b -binding (CAB) polypeptides was identified in Arabidopsis thaliana . This locus carries two genes in an inverted orientation. The predicted sequences of the polypeptides encoded by these two genes show substantial divergence in their amino termini relative to each other and to the proteins encoded by the three Lhb1 CAB genes previously characterized [10], but little divergence within the predicted primary structure of the mature protein. DNA probes derived from seven additional types of tomato CAB genes, encoding chlorophyll a/b -binding polypeptides of several antenna systems of the photosynthetic apparatus, were tested against A. thaliana . Each of these hybridized in Southern blots to unique DNA fragment(s), demonstrating the existence of each of these different types of CAB genes in the genome of A. thaliana . The number of genes encoding each CAB type in A. thaliana was estimated to be similar to that of tomato.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43432/1/11103_2004_Article_BF00027069.pd

The violent frontline: space, ethnicity and confronting the state in Edwardian Spitalfields and 1980s Brixton

This article discusses in comparative terms the relationship between space, ethnic identity, subaltern status and anti-state violence in twentieth century London. It does so by comparing two examples in which the control of the state, as represented by the Metropolitan Police, was challenged by minority groups through physical force. It will examine the Spitalfields riots of 1906, which began as strike action by predominantly Jewish bakers and escalated into a general confrontation between the local population and the police, and the Brixton riots of 1981, a response to endemic police harassment of mainly Caribbean youth and long-term economic discrimination in that area of South London. It will begin by dissecting the association of physical metropolitan space with the diasporic ‘other’ in the Edwardian East End and post-consensus South London, and how this ‘othering’ was influenced both by the state and the anti-migrant far right. It will then interrogate the difficult relationship between the Metropolitan Police and Jewish and Caribbean working class communities, and how this deteriorating relationship exploded into in extreme violence in 1906 and 1981. The article will conclude by assessing how the relationships between space, identity and violence influenced long-term national and communal narratives of Jewish and Caribbean interactions with the British state

Signal processing and transduction in plant cells: the end of the beginning?

Plants have a very different lifestyle to animals, and one might expect that unique molecules and processes would underpin plant-cell signal transduction. But, with a few notable exceptions, the list is remarkably familiar and could have been constructed from animal studies. Wherein, then, does lifestyle specificity emerge

Minority environmental activism in Britain: From brixton to the lake district

Historically, the British environmental movement has been devoid of minority participation, but this is changing very slowly, with the emergence of ethnic minority environmental groups and multiracial environmental alliances. These groups have argued that ethnic minorities have little or no access to public funds earmarked for countryside and wildlife preservation issues. They argue that white environmental organizations do not pay attention to the needs of inner-city minority residents and minority access to the countryside. Increased access, community improvement and beautification projects, environmental education, youth training, community garden projects, and issues of environmental racism are all foci of ethnic minority environmental movements. While some white environmentalists have been supportive of them, others have been uncomfortable with them or even hostile to their existence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43549/1/11133_2004_Article_BF00990102.pd

Plant training grant: DE-FG02-94ER20162. Final technical report

The aim of this training grant was to educate students of Plant Science in the disciplines of Biochemistry and Chemistry, in addition to the more traditional courses in Plant Biology. Annual retreats were held which involved a day-long meeting and included lectures from Penn faculty as well as famous national and international scientists. Programs for two of these retreats are included. In addition to lecture courses, students performed research within the Departments of Biology, Chemistry, and Biochemistry and Biophysics; a publications list is given