Knowledge about characteristics shared across known members of a protein family enables their identification within the complete set of proteins in an organism. Shared features are usually expressed through motifs, which can incorporate specific patterns and even amino acid (AA) biases. Based on a set of classification patterns and biases it can be determined which additional proteins may belong to a specific family and share its functionality. A bioinformatics tool (Prot-Class) was implemented to examine protein sequences and characterize them based upon user-defined AA composition percentages and user defined AA patterns. In addition the tool allows for the identification of repeated AA patterns, biased AA compositions within windows of user-defined length, and the characteristics of putative signal peptides and glycosylphosphatidylinositol (GPI) lipid anchors. ProtClass is general purpose and can be applied to analyze protein sequences from any organism. The Prot-Class source code is available through the GNU General Public License v3 and can be accessed via the Google Code Repository: http://code.google.com/p/prot-class/.

Arabidopsis thaliana (L.) Heyhn. is a well known model plant in plant research. However, its growth conditions and diminutive stature associated with low biomass at maturity make it a challenging species for physiological studies. While in the tropical countries, it can only be grown either by tissue cultures or in growth chambers under controlled conditions. An aeroponic technique with 20°C ± 2°C and 30°C ± 2°C root-zone temperatures (RZT) was used to grow Arabidopsis (Columbia ecotype) in a tropical greenhouse with natural irradiance and high ambient temperature (38°C/28°C day/night). Seedlings germinated in growth chambers at 20°C or 30°C. At 6 to 8 leaf stage, they were transferred to the aeroponic troughs with their roots exposed to constant temperature of 20°C ± 2°C and 30°C ± 2°C while their aerial parts were subjected to fluctuating ambient temperature from 28°C to 38°C. After a week, plants have acclimatised to both RZTs and started developing normal rosettes, bolted and yielded viable seeds. However, 20°C ± 2°C RZT allowed them to recover from turgor pressure despite of wilting, and significantly increased biomass. Mature plants grown in each RZTs were compared morphologically and physiologically to the plants grown in growth chamber (GC) at 20°C (root and shoot) temperature with 60% relative humidity. Aeroponically grown plants did not experience photoinhibition, and also exhibited higher photosynthetic light usage efficiency and higher capacities of heat dissipation, compared to GC plants. This aeroponics with cool RZTs can allow the use of Arabidopsis as a model plant even under tropical climate.