Roles of microRNA in plant defense and virus offense interaction

MicroRNAs (miRNA) that are around 22 nucleotides long non-protein-coding RNAs, play key regulatory roles in plants. Recent research findings show that miRNAs are involved in plant defense and viral offense systems. Advances in understanding the mechanism of miRNA biogenesis and evolution are useful for elucidating the complicated roles they play in viral infection networks. In this paper a brief summary of evolution of plant anti-virus defense is given and the function of miRNAs involved in plant-virus competition is highlighted. It is believed that miRNAs have several advantages over homology-dependent and siRNA-mediated gene silencing when they are applied biotechnologically to promote plant anti-virus defense. miRNA-mediated anti-virus pathway is an ancient mechanism with a promising future. However, using miRNAs as a powerful anti-virus tool will be better realized only if miRNA genomics and functions in plant viral infection are fully understood.

Changes in plant biomass and species composition of alpine Kobresia meadows along altitudinal gradient on the Qinghai-Tibetan Plateau

Alpine Kobresia meadows are major vegetation types on the Qinghai-Tibetan Plateau. There is growing concern over their relationships among biodiversity, productivity and environments. Despite the importance of species composition, species richness, the type of different growth forms, and plant biomass structure for Kobresia meadow ecosystems, few studies have been focused on the relationship between biomass and environmental gradient in the Kobresia meadow plant communities, particularly in relation to soil moisture and edaphic gradients. We measured the plant species composition, herbaceous litter, aboveground and belowground biomass in three Kobresia meadow plant communities in Haibei Alpine Meadow Ecosystem Research Station from 2001 to 2004. Community differences in plant species composition were reflected in biomass distribution. The total biomass showed a decrease from 13196.96 +/- 719.69 g/m(2) in the sedge-dominated K. tibetica swamp to 2869.58 +/- 147.52 g/m(2) in the forb and sedge dominated K. pygmaea meadow, and to 2153.08 +/- 141.95 g/m(2) in the forbs and grasses dominated K. humilis along with the increase of altitude. The vertical distribution of belowground biomass is distinct in the three meadow communities, and the belowground biomass at the depth of 0-10 cm in K. tibetica swamp meadow was significantly higher than that in K. humilis and K. pygmaea meadows (P < 0.01). The herbaceous litter in K. tibetica swamp was significantly higher than those in K. pygnaeca and K. humilis meadows. The effects of plant litter are enhanced when ground water and soil moisture levels are raised. The relative importance of litter and vegetation may vary with soil water availability. In the K. tibetica swamp, total biomass was negatively correlated to species richness (P < 0.05); aboveground biomass was positively correlated to soil organic matter, soil moisture, and plant cover (P < 0.05); belowground biomass was positively correlated with soil moisture (P < 0.05). However, in the K. pygnaeca and K. humilis meadow communities, aboveground biomass was positively correlated to soil organic matter and soil total nitrogen (P < 0.05). This suggests that the distribution of biomass coincided with soil moisture and edaphic gradient in alpine meadows.

Response of chlorophyll fluorescence to dynamic light in three alpine species differing in plant architecture

A study was carried out to examine the effect of dynamic photosynthetically active photon flux density (PPFD) on photoinhibition and energy use in three herbaceous species, prostrate Saussurea superba, erect-leaved S. katochaete, and half-erect-leaved Gentiana straminea, from the Qinghai-Tibet Plateau. Chlorophyll fluorescence response was measured under each of three sets of high-low PPFD combinations: 1700-0, 1400-300, and 1200-500 mu mol m(-2) s(-1), illuminating in four dynamic frequencies: 1, 5, 15, and 60 cycles per 2 h. The total light exposure time was 2h and the integrated PPFD was the same in all treatments. The highest frequency of PPFD fluctuation resulted in the lowest photochemical activity, the highest level of non-photochemical quenching, and the greatest decrease of F-v/F-m (maximal photochemical efficiency of PSII). The 5 and 15 cycles per 2h treatments resulted in higher photochemical activity than the 1 cycle per 2h treatment. The 1700-0 PPFD combination led to the lowest photochemical activity and more serious photoinhibition in all species. S. superba usually exhibited the highest photochemical activity and CO2 uptake rate, the lowest reduction of F-v/F-m,F- and the smallest fraction of energy in thermal dissipation. With similar fractions of thermal dissipation, S. katochaete had relatively less photoinhibition than G. straminea owing to effective F-o quenching. The results suggest that high frequency of fluctuating PPFD generally results in photoinhibition, which is more serious under periods of irradiation with high light intensity. (c) 2005 Elsevier B.V. All rights reserved.

Uptake and use of electronic information services: trends in UK higher education from the JUSTEIS project

Urquhart, C., Lonsdale, R.,Thomas, R., Spink, S., Yeoman, A., Armstrong, C. & Fenton, R. (2003). Uptake and use of electronic information services: trends in UK higher education from the JUSTEIS project. Program, 37(3), 167-180. Sponsorship: JISC

Genetic deficiency of the fourth component of complement :clinical, immunological and genetical studies in a further family. IXth International Complement Workshop

info:eu-repo/semantics/published

Characterizing mentors’ performance in mathematics teacher education

This study describes the performance of the mentors in a blended graduate-level training program of teachers in the field of secondary school mathematics. We codified and analyzed the mentors’ comments on the projects presented by the groups of in-service teachers for whom they (the mentors) were responsible. To do this, we developed a structure of categories and codes based on a combination of a literature review, a model of teacher learning, and a cyclical review of the data. We performed two types of analysis: frequency and cluster. The first analysis permitted us to characterize the common actions shared by most of the mentors. From the second, we established three profiles of the mentors’ actions.

A survey of teaching and assessment methods employed in UK higher education programmes for HCI course

A survey of teaching and assessment methods employed in UK Higher Education programmes for Human-Computer Interaction (HCI) courses was conducted in April 2003. The findings from this survey are presented, and conclusions drawn.

A framework for e-learning: a blended solution?: current developments in technology-assisted education

This paper describes a Framework for e-Learning and presents the findings of a study investigating whether the use of Blended Learning can fulfill or at least accommodate some of the human requirements presently neglected by current e-Learning systems. This study evaluates the in-house system: Teachmat, and discusses how the use of Blended Learning has become increasingly prevalent as a result of its enhancement and expansion, its relationship to the human and pedagogical issues, and both the positive and negative implications of this reality. [From the Authors]

Creating a suitable and successful solution for the integration of podcasting and vidcasting in a higher education e-learning environment

A small research project is currently taking place within a department of the University of Greenwich. The project involves using current technology (Apple’s xServe, iPhones, iPod touch, Podcast Producer application and some 3rd party capture software) with the intention to provide a solution for quick and simple podcasting. This paper also aims to investigate the use of podcasting to help promote and extend the e-learning provision within the school. In short this project aims to justify the use of podcasting as a teaching and learning tool to help enhance student learning while identifying the most appropriate manner to integrate podcasting within an e-learning environment.

Chloroplast microsatellites: new tools for studies in plant ecology and systematics

The nonrecombinant, uniparentally inherited nature of organelle genomes
makes them useful tools for evolutionary studies. However, in plants, detecting
useful polymorphism at the population level is often difficult because of the
low level of substitutions in the chloroplast genome, and because of the slow
substitution rates and intramolecular recombination of mtDNA. Chloroplast
microsatellites represent potentially useful markers to circumvent this problem
and, to date, studies have demonstrated high levels of intraspecific variability.
Here,we discuss the use of these markers in ecological and evolutionary
studies of plants, as well as highlighting some of the potential problems
associated with such use.

Celtic languages in European Higher Education: CRAMLAP - Celtic, Regional and Minority Languages Abroad Project

The Celtic, Regional and Minority Languages Abroad
Project (CRAMLAP) is funded by the European Commission
to research the provision and pedagogy of regional
and minority languages outside their national borders in
Europe. The teaching of Celtic languages across Europe
was the focus in year one (2003-2004). This article summarizes
the qualitative data received in response to
questionnaires sent to institutions across Europe offering
Celtic Studies. Responses indicated that Celtic Studies
are quite widely available across Europe. The languages
are taught in comparative linguistics, linguistics and English
departments, with few dedicated Celtic departments
or sections outside the Celtic countries. Irish is supported
abroad by Irish government grant aid which will
become more widely available in the immediate future.
Many of the teachers have considerable experience, but
limited pedagogic training. The lack of suitable teaching
resources is the most commonly expressed concern.