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Draw
circular and linear map of a plasmid by DNAMAN
DNAMAN
is an important tool to draw circular and linear map of a
plasmid. Run the program of DNAMAN, then click button "restriction"
and select "draw map". Double click the model of circle map,
a window of "Restriction Map Properties" appeared. Select
"circular" if you want to draw circular map or "linear" if
you want to draw linear map. Input plasmid name and size,
then click "Elements" to add promoter, gene and terminator.
Click "Enzyme Sites" to add necessary enzyme sites. Click
"Text" to add gene name and something else.
How
to design PCR primers and how to process sequence alignment
were also introduced in the report.
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How
Plants Fight Against Drought Stress
Water
is vital to important plant physiological processes, eg. the
transpiration, the formation of vacuole and so on. Water deficit,
which is rather a disaster for plants, can be caused by versatile
environmental factors, such as dehydration, high or low temperature
and salt stress. On the other hand, many plants can tolerate
moderate dehydration, and some species even grow passably
under severe dehydration or resurrect quickly when water is
acquirable. The question of plants' tolerance mechanisms has
been arousing many plant physiologists' interest.
It has been observed that plant adapts to water stress by
series of physiology responses including the closure of stoma,
and scientists have traditionally been concentrated mainly
on the morphologic differences of tolerant plants such as
leave’s structures. Due to the developments of molecular biology,
botanists begin to view this issue on molecular level. Recently,
there have been many exciting advancements in this area: many
stress-responsive genes have been cloned, and transgenic plants
have shown partial tolerance to water deficit. Moreover, scientists
come to understand some sigal transduction pathways in water
stress, in which the following focuses are arising:
1.the altered fluidity of membrane, the imbalance of cellular
and extracellular ion level, and the variances of normal structures;
2.the function of an essential plant hormone abscisic acid
;
3.specific transcription factors regulating down-stream genes'
expression under different environment conditions;
4.quickly accumulating sugars , lea, scavengers and other
osmoprotectants under stress.
By
unwrapping this process, scientists will offer a promising
foreground to breed drought tolerant crops to contribute to
settle the latent scarcity of food and water resource, to
answer the question of plant's evolution from hydrophily to
xeromorphy, and might also to highlight a clue to species
diversity.
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