Solacure uses the T12 bulb, and says the size of the T12 is a critical aspect of creating higher energy levels of UVB. They said theyve tried T5-T8 and they dont measure up.
They also state their bulb is 20-50x more powerful than the best Reptile Bulbs, which is probably the Arcadia Desert Reptile 54w.
Then theres the UVR8 protein receptor. Which I think is on of the most critical aspects of using UVB lighting.
Science says the only way to activate the UVR8 receptor in plants, not just weed, is to supply UVB at the 285nm level.
What is the function of UVR8 in plants?
UVR8 is involved in controlling aspects of leaf growth and morphogenesis in response to UV-B, is required for normal progression of endocycle and has a regulatory role in stomatal differentiation. Is required for plant circadian clock response to photomorphogenic UV-B light, partly through the transcriptional activation of responsive clock genes.
UV-B specific signaling component that acts as UV-B photoreceptor and plays a key role in establishing UV-protective responses in plants. Upon UV-B irradiation, UVR8 undergoes an immediate switch from homodimer to monomer, accumulates in the nucleus, interacts with the photomorphogenic repressor COP1 and regulates the expression of the transcription factor HY5 by associating with chromatin (through histone H2B binding) in the HY5 promoter region. UVR8 is involved in controlling aspects of leaf growth and morphogenesis in response to UV-B, is required for normal progression of endocycle and has a regulatory role in stomatal differentiation. Is required for plant circadian clock response to photomorphogenic UV-B light, partly through the transcriptional activation of responsive clock genes. Promotes photosynthetic efficiency at elevated levels of UV-B. Plays a role in mediating the effects of UV-B radiation on pathogen resistance by controlling the expression of the sinapate biosynthetic pathway. The two tryptophans, Trp-285 and Trp-233, serve collectively as the UV-B chromophore.
In the case of UVR8, a set of biochemical and genetic data strongly indicated that an intrinsic tryptophan, namely tryptophan-285 (Trp-285 or W285), functions as a chromophore for UV-B perception (
Rizzini et al. 2011). In agreement, purified UVR8 dimer devoid of any form of prosthetic chromophore is able to perceive UV-B and monomerize in vitro (
Christie et al. 2012,
Wu et al. 2012).
Tryptophan is a naturally UV-absorbing aromatic amino acid. Sequence analysis shows that UVR8 is particularly enriched in tryptophans, which can be found 14 times in UVR8 versus only 4 times in human RCC1 (Regulator of Chromosome Condensation), which is structurally related to UVR8 (
Kliebenstein et al. 2002,
Rizzini et al. 2011,
Wu et al. 2011). Trp-285 was shown to be essential for UVR8 monomerization as mutation of Trp-285 to phenylalanine (UVR8W285F) rendered UVR8 as a constitutive dimer whereas Trp-285 to alanine (UVR8W285A) resulted in a constitutive UVR8 monomer (
Rizzini et al. 2011). However, it should be noted here that the constitutive monomer form of UVR8m285A is apparent with gel electrophoresis of nonboiled protein extracts from yeast and plants (
Rizzini et al. 2011,
O'Hara and Jenkins 2012). In contrast with these gel-based assays, size exclusion chromatography showed that purified UVR8W285A is a dimer in vitro that does not monomerize in response to UV-B (
Christie et al. 2012,
Wu et al. 2012). However, the available data suggests that UVR8W285A is a weak dimer and that the mutant protein very likely exists as a monomer in vivo (
Rizzini et al. 2011,
O'Hara and Jenkins 2012). Notwithstanding this, further structural and biophysical studies have since confirmed and further detailed the importance of Trp-285 in UV-B perception (
Christie et al. 2012,
Wu et al. 2012).
Structural basis of UVR8 dimer formation and UV-B-dependent monomerization
Several recent works have revealed much about how UVR8 exists as a homodimer capable of monomerization upon UV-B exposure. These publications present UVR8 predictive models arising from biochemical and structural analysis followed up by systematic mutational analysis of key residues. Of the 14 UVR8 tryptophans mentioned above, six (plus 1 tyrosine) are located within the protein core contributing to maintain the β-propeller structure, one is situated in the C-terminal part that was not included in the core structure, and seven are found at the homodimeric interface (
Christie et al. 2012,
O'Hara and Jenkins 2012,
Wu et al. 2012) (
Figure 5). Amongst the tryptophans at the dimer interface, mutational analysis showed that Trp-233, Trp-285, Trp-337 and Trp-94 of the opposing UVR8 monomer contribute to exciton coupling within the structure (
Christie et al. 2012). These four residues were thus proposed to form a cross-dimer “tryptophan pyramid” involved in UV-B sensing (i.e. two “pyramids” per UVR8 homodimer) (
Christie et al. 2012). Indeed, previous work mentioned above highlighted the importance of Trp-285 in maintaining the UVR8 homodimer, as UVR8W285A rendered UVR8 as a monomer that constitutively interacted with CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1; At2g32950) in yeast (
Rizzini et al. 2011). However, whether each of the four “pyramid” tryptophans play a role in UV-B perception is unclear. Whereas UVR8W285F prevented UV-B-mediated monomerisation of the UVR8 homodimer, Trp-337 to phenylalanine (UVR8W337F) did not (
Rizzini et al. 2011,
Christie et al. 2012). Furthermore, an independent study also showed that mutation of Trp-337, as well as Trp-94, to phenylalanine (UVR8W337F, UVR8W94F) did not affect UV-B perception (
Wu et al. 2012). A follow up comprehensive analysis described transgenic plants where each of the 14 tryptophan residues within UVR8 were mutated (
O'Hara and Jenkins 2012). This study confirmed that Trp-285 in particular as well as Trp-233 play important roles in UV-B perception, and that Trp-337 contributes to but is not essential for this same process. Concurrently, mutation of Trp-94 did not affect UVR8 monomerisation upon UV-B indicating that a tryptophan “pyramid” structure per se is not required for UV-B perception. Interestingly, UVR8W285F was found to be weakly responsive to UV-C in vitro which is not the case for wild type UVR8 (
Christie et al. 2012). This is in accordance with the absorption properties of phenylalanine versus tryptophan.
https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=3711356_f05_01.jpg
The UVR8 UV-B Photoreceptor: Perception, Signaling and ...
Jun 11, 2013 ·
UVR8 is a 440-amino-acid protein whose β-propeller structure is described above. Proven mutant alleles that abolish COP1 interaction include
uvr8–15 (
UVR8 G145S),
uvr8–9 (
UVR8 G202R) (Favory et al. 2009, Rizzini et al. 2011),
UVR8 G197A and
UVR8 G199A (O'Hara and Jenkins 2012) as well as
uvr8–2 (
UVR8 δC40) (Cloix et al. 2012).
- Cited by: 236
- Publish Year: 2013
- Author: Kimberley Tilbrook, Adriana Beatriz Arongaus, Mela
Isreal also did a study on the Red spectrum some 2o-30 years ago. They did a side by side comparison with flowers/tissue cultured flowers. They infused one greenhouse with Red, and the other with nothing, and the Red infused flowers were twice, or more as big vs the non Red infused.
UVR8 - Wikipedia
en.wikipedia.org
https://www.bing.com/search?q=uvr8&qs=n&form=QBRE&sp=-1&pq=uvr8&sc=8-4&sk=&cvid=F58ED0F633924E5EBCCCB863059AA146#
