More THC testing – UVA vs UVB vs near-UV

[jimihendrix1]

1. UVR8 - Ultraviolet-B receptor UVR8 - Arabidopsis thaliana ...
   
   UniProt

   www.uniprot.org
   Mar 01, 2001 · 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.

It states righ in this info that UVB is required for controlling aspects of leaf growth and morphogenesis in response to UV-B.
UVB only goes to 320nm.


View attachment 5036820

The UVR8 UV-B Photoreceptor: Perception, Signaling and Response
Kimberley Tilbrook, Adriana B. Arongaus, Melanie Binkert, Marc Heijde, Ruohe Yin, and Roman Ulm1


Ultraviolet-B radiation (UV-B) is an intrinsic part of sunlight that is accompanied by significant biological effects. Plants are able to perceive UV-B using the UV-B photoreceptor UVR8 which is linked to a specific molecular signaling pathway and leads to UV-B acclimation. Herein we review the biological process in plants from initial UV-B perception and signal transduction through to the known UV-B responses that promote survival in sunlight. The UVR8 UV-B photoreceptor exists as a homodimer that instantly monomerises upon UV-B absorption via specific intrinsic tryptophans which act as UV-B chromophores. The UVR8 monomer interacts with COP1, an E3 ubiquitin ligase, initiating a molecular signaling pathway that leads to gene expression changes. This signaling output leads to UVR8-dependent responses including UV-B-induced photomorphogenesis and the accumulation of UV-B-absorbing flavonols. Negative feedback regulation of the pathway is provided by the WD40-repeat proteins RUP1 and RUP2, which facilitate UVR8 redimerization, disrupting the UVR8-COP1 interaction. Despite rapid advancements in the field of recent years, further components of UVR8 UV-B signaling are constantly emerging, and the precise interplay of these and the established players UVR8, COP1, RUP1, RUP2 and HY5 needs to be defined. UVR8 UV-B signaling represents our further understanding of how plants are able to sense their light environment and adjust their growth accordingly.

These receptors allow the plant to deploy wavelength-specific responses. Specific light perception helps the plant optimize photon capture and photosynthesis in sunlight by regulating processes like de-etiolation, phototropism, shade-avoidance, stomatal opening and the intracellular distribution of chloroplasts in response to weak or strong light intensity. More indirectly, light optimizes plant growth and reproductive success by regulating germination, flowering and entrainment of the circadian clock (Sullivan and Deng 2003, Kami et al. 2010, Arsovski et al. 2012). However, plants maintain a love/hate relationship with sunlight, as illustrated by high light stress (Li et al. 2009, Takahashi and Badger 2011) and potentially harmful UV-B radiation (herein referred to as UV-B).

These receptors allow the plant to deploy wavelength-specific responses
In fact this article states the receptors allow Wavelength Specific Responses.

UV-B
UV-B (280–315 nm) comprises one of the three classes of ultraviolet radiation and is positioned between UV-A (315–400 nm) and UV-C (100–280 nm) in the electromagnetic spectrum (Figure 1). The permeability of the atmospheric ozone layer to UV radiation begins within the UV-B range of wavelengths. Hence, natural sunlight contains UV-A and a part of UV-B. . The level of UV-B reaching the earth's surface is highly dynamic and depends on large-scale factors such as stratospheric ozone, solar angle (latitude, season, time of day), altitude, tropospheric pollution and cloud cover, and small-scale variables such as surface reflectance and shading, e.g. in plant canopies (McKenzie et al. 2003, Paul and Gwynn-Jones 2003). However, UV-B makes up less than 0.5% of solar energy at the earth's surface (Blumthaler 1993). Regardless, the biological effects of UV-B are significant due to the energy that short-wavelength UV-B photons contain. An array of biologically active molecules, including nucleic acids, can absorb UV-B which leads to damage (e.g. DNA damage). Thus, UV-B is a potential abiotic stress factor for any organism exposed to sunlight, and particularly for photosynthetic organisms such as plants. Nevertheless, as can be appreciated in nature when wandering through exposed fields, plants are able to tolerate UV-B even under levels that accompany a long summer day with damage only seldom observed. Plants are indeed able to acclimate to UV-B, and a unique molecular signaling pathway exists to facilitate this (Figure 2). UV-B perception is via the UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8; At5g63860) which is linked to a signal-ing pathway that leads to a complex series of plant responses to UV-B (Heijde and Ulm 2012).



Seems to me UVB is very important.
View attachment 5036829
Figure 4.
The UVR8 photocycle.
The UVR8 homodimer is monomerised by UV-B, with UV-B absorption proceeding via a tryptophan-based chromophore. The UVR8 monomer interacts directly with COP1 to initiate UV-B signaling. UVR8 monomer is redimerized through the action of RUP1 and RUP2, which disrupts the UVR8-COP1 interaction, inactivates the signaling pathway and regenerates the UVR8 homodimer again ready for UV-B perception.

 

[jimihendrix1]

UVR8 structure and perception mechanism

Chromophore
Alight-reactive chromophore is needed for photoreceptor function. Many photoreceptors make use of bound cofactors as chromophores, for example phytochromobilin for phytochromes, flavin mononucleotide (FMN) for phototropins, and flavin adenine nucleotide (FAD) and possibly a pterin for cryptochromes (Kami et al. 2010, Liu et al. 2010) (Figure 1). 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).

 

[jimihendrix1]

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.
UVR8 structure and arrangement of key tryptophan and arginine residues.
(A) The arrangement of tryptophan (W) residues, excluding W400, in the UVR8 monomer as viewed from the side. The structure is shown for the solved core structure, amino acids 14 to 380 (Christie et al. 2012). Tryptophan residues located in the protein core are depicted in blue whereas those in red reside at the dimeric interaction surface. (B) As in (A), but viewed from the dimeric interaction surface. (C) Protein core tryptophan residues as viewed from the dimeric interaction surface. Each Trp is associated with a different propeller blade (numbered). Y248 from blade 5 completes the ring of aromatic residues. (D) Tryptophan residues at the dimeric interaction surface. Residues that constitute the tryptophan triad are depicted in magenta. Image reprinted from O'Hara and Jenkins (2012), with permission from The Plant Cell, Volume 24 © 2012 by the American Society of Plant Biologists (ASPB; www.aspb.org).
Looking further afield in the UVR8 protein, the arginine residues Arg146, Arg286 and Arg338 surrounding the four “pyramid” tryptophans were shown to participate in salt bridges and an extensive network of cation-Π interactions with the surrounding tryptophans (Christie et al. 2012, Wu et al. 2012). These bonds are critical for maintaining the UVR8 homodimer and their disturbance underlies UV-B perception. Overall, it has been reported that the homodimeric interface of UVR8 is mediated by 32 intermolecular hydrogen bonds, notably with eight intermolecular hydrogen bonds (four from each molecule) arising from Arg-286 (Wu et al. 2012). In agreement, mutation of Arg-286 to alanine (UVR8R286A) creates a constitutive UVR8 monomer (Christie et al. 2012, Wu et al. 2012).
In summary, the current consensus is that UV-B perception by UVR8 is mediated by a chromophore made up of at least Trp-285 and Trp-233, which directly absorb and are excited by UV-B. The excited states of Trp-285 and Trp-233 are then unable to maintain a number of intramolecular cation-Π interactions with surrounding residues, in particular with Arg-286 and Arg-338. These disrupted cation-Π interactions in turn destabilize the intermolecular hydrogen bonds of the UVR8 homodimeric interface leading to homodimer dissociation and initiation of UV-B signaling (Christieet al. 2012, Wu et al. 2012). It is of note here that the UVR8 crystal structure was resolved and analysed for the core sequence of UVR8 and in fact a C-terminal fragment required for signaling (Cloix et al. 2012) and an N-terminal fragment required for nuclear translocation (Kaiserli and Jenkins 2007) have not yet been included in any structural analysis (Christie et al. 2012, Wu et al. 2012). Therefore, although the crystal structure of UVR8 provides insight into the photoperception mechanism, it does not yet show how UVR8 initiates signaling through interaction with the downstream factor COP1, which, as is detailed in following sections, seems as crucial for UV-B signaling as UVR8 monomerisation.

 

[jimihendrix1]

UVR8 inactivation and around state reversion
As for any photoreceptor, inactivation and ground (“dark”) state reversion of UVR8 is of great importance. UVR8 reverts back to its homodimeric ground state by redimerization, which simultaneously stops UV-B signaling and restores UV-B responsiveness (Heijde and Ulm 2013, Heilmann and Jenkins 2013) (Figure 4). Regeneration of the UVR8 dimer following UV-B exposure occurs much more rapidly in vivo (1–2 hours) than in vitro (24–48 hours) (Christie et al. 2012, Wu et al. 2012, Heijde and Ulm 2013, Heilmann and Jenkins 2013). This is largely due to activ-ity of the WD40-repeat proteins REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 and 2 (RUP1; At5g52250, and RUP2; At5g23730) that promotes the redimerization of UVR8 in vivo (Heijde and Ulm 2013) (Figure 4). Thus, whereas monomerization of UVR8 under UV-B is an intrinsic property of the protein, its natural means of reversion to a homodimer is dependent on interaction with regulatory proteins, as is described in further detail in following sections.

Expression and subcellular localization of UVR8
The expression and subcellular localisation of plant photoreceptors plays a large role in their biological function and how the signaling pathways they are linked to proceed. UVR8 is expressed throughout plant bodies, which technically gives any plant organ the ability to respond to UV-B (Rizzini et al. 2011). The majority of UVR8 protein is located in the cytoplasm but a small portion is also detectable in the nucleus, even in the absence of UV-B. Upon UV-B exposure, UVR8 is seen to accumulate within minutes in the nucleus, although not exclusively, as the majority of UVR8 remains cytoplasmic (Kaiserli and Jenkins 2007). The rapid UV-B-dependent nuclear accumulation of UVR8 artificially localised in the cytoplasm (i.e. fused with a nuclear export signal) suggests that a specific nuclear transport mechanism exists (Kaiserli and Jenkins 2007). This combined with the fact that UVR8 protein levels are unchanged by UV-B (Kaiserli and Jenkins 2007, Favory et al. 2009) rules out the possibility that nuclear UVR8 accumulation is the result of differential protein stabilization upon UV-B exposure. However, no clear nuclear localisation signal motif can be identified in the UVR8 sequence and the mechanism for UVR8 nuclear accumulation remains unknown. Nevertheless, removal of the N-terminal 23 amino acids (N23) of UVR8 prevents the protein from accumulating in the nucleus under UV-B, suggesting that this stretch of amino acids plays an important role in nuclear translocation (Kaiserli and Jenkins 2007) (Figure 3B). UVR8 nuclear localisation is necessary but not sufficient for UV-B signaling, as demonstrated by the requirement of UV-B for initiation of the pathway even when UVR8 is fused with a nuclear localisation signal and is constitutively nuclear (Kaiserli and Jenkins 2007). As mentioned above, the majority of UVR8 is retained in the cytoplasm under UV-B (Kaiserli and Jenkins 2007). This is interesting in light of the apparent necessity for UVR8 to be in the nucleus for UV-B signaling leading to changes in gene expression. Thus, a functional role for UVR8 in the cytoplasm cannot be ruled out at present, but most of the available evidence indicates its central function in UV-B signaling is in the nucleus.

Again. I see ZERO about anything to do with UVA for triggering the UVR8 Receptor.

UVR8 is the only known plant photoreceptor that mediates light responses to UV-B (280-315 nm) of the solar spectrum. UVR8 perceives a UV-B signal via light-induced dimer dissociation, which triggers a wide range of cellular responses involved in photo-morphogenesis and photo-protection. Two recent crystal structures of Arabidopsis thaliana UVR8 (AtUVR have revealed unusual clustering of UV-B-absorbing Trp pigments at the dimer interface and provided a structural framework for further mechanistic investigation. This review summarizes recent advances in spectroscopic, computational and crystallographic studies on UVR8 that are directed towards full understanding of UV-B perception at the molecular level.

Again I see no indication that the UVA spectrum activates the UVR8 receptor.

 

[Grow Lights Australia]

Hello, I see you have copy and posted lots of scientific information (some of which is 20 years old!) but I am having a hard time understanding what it all means. Can you please explain in your own words what these things mean? I'm sure we could all learn a lot from someone who understands the UVR8 receptor as well as you do. You seem to know more about it than anyone else on RIU.

It states righ in this info that UVB is required for controlling aspects of leaf growth and morphogenesis in response to UV-B.
UVB only goes to 320nm.

That is only in response to UVB. As you would expect. But can you explain to us what aspects of leaf growth and morphogenesis are changed and why? How does it benefit the plant?

Seems to me UVB is very important.

Can you please tell us why UVB is so important when plants don't need it to grow? What do you mean by "UVB is very important"?

The UVR8 homodimer is monomerised by UV-B, with UV-B absorption proceeding via a tryptophan-based chromophore. The UVR8 monomer interacts directly with COP1 to initiate UV-B signaling. UVR8 monomer is redimerized through the action of RUP1 and RUP2, which disrupts the UVR8-COP1 interaction, inactivates the signaling pathway and regenerates the UVR8 homodimer again ready for UV-B perception.

Can you also explain what this means please? You have posted lots of information regarding monomerisation of the UVR8 homodimer. What is "monomerisation of the UVR8 homodimer"? What are you trying to say?

As you can appreciate this thread is for discussing ideas and is not intended to be a "copy and paste dump". I for one would really like to know why the UVR8 receptor does not absorb other wavelengths and what happens to the UVR8 receptor when there is no UVB present? Many generations of cannabis have been grown indoors over decades without UVB and yet the plant is still able to produce cannabinoids. How is this possible if the UVR8 receptor is responsible for this and is not exposed to UVB like you say?

You said earlier that UVR8 only absorbs 285nm. But now you are saying it only absorbs UVB (280-310nm). Are you saying that the UVR8 absorption curve that was posted earlier is wrong? We would all really appreciate if you did not just copy and past things like you have been doing and just explain everything in your own words like everyone else here has been doing so that we can all understand. Thank you for your contribution.

 

[jimihendrix1]

I never said UVR8 is only activated at 280nm. I said that is where the strongest response happens. 285nm-290nm. Which any bulb in the 280nm-290nm range would be the most efficient, thus enabling one not to have to run their lights as long, which would both conserve energy, and extend the life of the bulb, because the bulb(s) wouldnt have to run as long to elict a response. But I never said 280nm was the only wavelength to activate RVR8,
The solacure bulb has its strongest output at 280nm-300nm

It means UVR8 is only activated in the 280nm-315nm range, with the strongest reponse from 280nm-290nm, and also all of the chemical reactions that happen when one activates UVR8. I also left out tons of other information.

Theres absoutely no mention of any light spectrum over 315nm that activates UVR8, and that the strongest response starts at 280nm- 290nm, which would make any bulb more efficient in the 285nm range.

But theres no mention of UVA activating the UVR8 receptor. They mention that 385nm range has a synergistic effect, when combined with 285nm wavelength

I also showed a study earlier where the University of Maryland, a highly respected agricultural reserch college, used a Westinghous FS40 bulb that also goes down to the 285nm range that was used to activate UVR8, not Solacure.
Solacure is only stating what known research states. Not just them running their mouths

I also showed research that stated when 285nm of light, combined with 385nm of light has a synergistic effect


This also isnt SOLACURE AND HAS NOTHING TO DO WITH SOLACURE



UVR8 Chemical Profile Shaping in Cannabis

Research has proven that 285 nm UVB triggers the UVR8 pathway, which increases the production of secondary metabolites that mediate many aspects of the interaction of plants with their environment such as acting as feeding deterrents against herbivores, pollinator attractants, protective compounds against pathogens or various abiotic stresses, antioxidants, and signalling molecules.


385 nm light is on the boundary of UVA and visible light. It is proven to increase cell wall thickness and health, making the plant more resilient against intense UV, pests, mold, and mildew.

A friendly warning: Not all UV is created equal.

Some lighting manufacturers include a portion of UVA in their spectrum . Although these amounts do increase secondary metabolite production to some extent, they do not effectively trigger the UVR8 chemical pathway. This specifically requires 290 to 280 nm light.
Using the correct UV wavelength is extremely important as it affects plant performance as well as operating cost. UVB requires more energy than visible light to produce.

Using the correct UV wavelength is extremely important as it affects plant performance as well as operating cost. UVB requires more energy than visible light to produce.
385 nm light is on the boundary of UVA and visible light. It is proven to increase cell wall thickness and health, making the plant more resilient against intense UV, pests, mold, and mildew.

A friendly warning: Not all UV is created equal.

Some lighting manufacturers include a portion of UVA in their spectrum . Although these amounts do increase secondary metabolite production to some extent, they do not effectively trigger the UVR8 chemical pathway. This specifically requires 280nm to 290nm light.
Using the correct UV wavelength is extremely important as it affects plant performance as well as operating cost. UVB requires more energy than visible light to produce.


This study is very specific about saying that plants elict the strongest response to UVR8 at 280nm-290nm of light, and this isnt the only study Ive shown stating as much.

Its simple enough for me to understand that every study Ive read about activating UVR8, is that it elicts the strongest response from 280nm-290nm.

And these studies are not Solacure related, and some of them were done at highly renown Agriculture Research Colleges. Ive not read one shred of information that UVR8 is activated by UVA, only that 385nm UVA elicts a synergistic reaction, when combined with 280nm-290nm of light. And while 291nm-315nm will activate the UVR8 receptor, it is not the most efficient. The studies are adamant that plants get the strongest response from 280nm-290nmnm. Namely 285nm.

 

[grotbags]

did you see this pic that was posted earlier?...

it shows you the response curve of the uvr8 receptor, yes its strongest at 285nm, but their is a deminishing response all the way to 425nm.

The response may be strongest ~285nm (and/or in synergy with ~365nm), but ALL light in the absorption spectra create pathways. This is perhaps what some people are missing. You only need a small amount of UVB around 285nm to trigger production of phenolics, but you can expose the plant to larger amounts of longer wavelengths (up to 420nm) to elicit the same response. That is what the curve is telling us.

If the UVR8 receptor was only triggered by 285nm, then there would be no absorption curve – there would be a spike right at 285nm.

 

[jimihendrix1]

All the studies Ive read say the response curve is most efficient at 280nm-290nm, and all of the studies Ive seen use 280nm-290nm as the basis of their studies. Nothing over 290nm. They do state that 315nm will elict a response, but anything over 290nm, is not efficient, and doesnt elict the strongest response. Not one of them used anything over 290nm for their research, and that 280nm-290nm combined with 385nm is the most efficient.

The study I just posted is adamant, and says all UV is not created equally. They are not impressed with UVA as a trigger for UVR8 receptor. They state as much plainly.



A friendly warning: Not all UV is created equal.

Some lighting manufacturers include a portion of UVA in their spectrum . Although these amounts do increase secondary metabolite production to some extent, they do not effectively trigger the UVR8 chemical pathway. This specifically requires 280nm to 290nm light. Up to 315nm works, but is not as efficient.
Using the correct UV wavelength is extremely important as it affects plant performance as well as operating cost. UVB requires more energy than visible light to produce.

 

[grotbags]

ll the studies Ive read say the response urve is most efficient at 290nm-290nm, and all of the studies Ive seen use 289nm-290nm as the basis of their studies. Nothing over 290nm. Not one of them used anything over 290nm for their research

yep perfectly reasonable, and if i was doing the studies on uvr8 response i too would use something as close to 285nm as possible without straying into uvc hence the use of 290nm...
but you can see that there is a response of the uvr8 receptor past 280nm all the way to 420nm ish? no?...

 

[jimihendrix1]

Study says it specificaally requires 280nm-290nm of light. They say anything other than 280nm-290nm is not as efficient, only that anything over 315nm increases seconday metabolism.

Some lighting manufacturers include a portion of UVA in their spectrum . Although these amounts do increase secondary metabolite production to some extent, they do not effectively trigger the UVR8 chemical pathway

A friendly warning: Not all UV is created equal.

Some lighting manufacturers include a portion of UVA in their spectrum . Although these amounts do increase secondary metabolite production to some extent, they do not effectively trigger the UVR8 chemical pathway. This specifically requires 280nm to 290nm light.
Using the correct UV wavelength is extremely important as it affects plant performance as well as operating cost. UVB requires more energy than visible light to produce.

Quote

. . Although these amounts do increase secondary metabolite production to some extent......They Do Not effectively trigger the UVR8 chemical pathway

Thats plain enough to me

 

[Prawn Connery]

Instead of spamming the same Solacure crap post after post, why don't you answer the questions @Grow Lights Australia asked you?

 

[Rocket Soul]

Instead of spamming the same Solacure crap post after post, why don't you answer the questions @Grow Lights Australia asked you?

There is also a point in mentioning that a fair bit of testing has been done with both gen1 and gen2 of the highlights. Maybe not of full on academic methodology but the results was higher thc in the sample with no uvb, ample +400nm violet, than in the sample with uvb florescent added. This goes quite opposite to what jimi is claiming above and any uv science paper worth its shit should be able to explain this if its claiming that only uvr8 can raise thc.

This is not to say that i am against adding uvb. From what i hear from people tried it theres a definite plus and a change to the better. But i think there is "low hanging fruit" to be reached by adding some uva or violet.

Another thing to mention: why think that uvr8 is the only noteworthy effect of uvb?
Is there any indication that uvr8 is the only thing activated?

 

[Prawn Connery]

There is also a point in mentioning that a fair bit of testing has been done with both gen1 and gen2 of the highlights. Maybe not of full on academic methodology but the results was higher thc in the sample with no uvb, ample +400nm violet, than in the sample with uvb florescent added. This goes quite opposite to what jimi is claiming above and any uv science paper worth its shit should be able to explain this if its claiming that only uvr8 can raise thc.

This is not to say that i am against adding uvb. From what i hear from people tried it theres a definite plus and a change to the better. But i think there is "low hanging fruit" to be reached by adding some uva or violet.

Another thing to mention: why think that uvr8 is the only noteworthy effect of uvb?
Is there any indication that uvr8 is the only thing activated?

He's just a shill for Solacure who hasn't even read through this thread. Because if he has, he sure as shit hasn't understood any of it.

I never said UVR8 is only activated at 280nm. I said that is where the strongest response happens. 285nm-290nm.

Science says the only way to activate the UVR8 receptor in plants, not just weed, is to supply UVB at the 285nm level.

Too late to get your story straight mate – we've already seen through you.

 

[Prawn Connery]

I'm posting this for everyone who is interested. Note the parts in bold. This is pretty much what I have been saying. The only difference is, after having conducted numerous experiements on the subject, we believe the UVR8 receptor also plays a part in detecting and responding to ALL UV radiation in the response curve.

Perception of solar UV radiation by plants: photoreceptors and mechanisms

In sunlight, UVR8 mediates the perception of both UV-B and short-wavelength UV-A radiation with its sensitivity moderated by blue light perceived through c

academic.oup.com

Abstract
About 95% of the ultraviolet (UV) photons reaching the Earth’s surface are UV-A (315–400 nm) photons. Plant responses to UV-A radiation have been less frequently studied than those to UV-B (280–315 nm) radiation. Most previous studies on UV-A radiation have used an unrealistic balance between UV-A, UV-B, and photosynthetically active radiation (PAR). Consequently, results from these studies are difficult to interpret from an ecological perspective, leaving an important gap in our understanding of the perception of solar UV radiation by plants. Previously, it was assumed UV-A/blue photoreceptors, cryptochromes and phototropins mediated photomorphogenic responses to UV-A radiation and “UV-B photoreceptor” UV RESISTANCE LOCUS 8 (UVR to UV-B radiation. However, our understanding of how UV-A radiation is perceived by plants has recently improved. Experiments using a realistic balance between UV-B, UV-A, and PAR have demonstrated that UVR8 can play a major role in the perception of both UV-B and short-wavelength UV-A (UV-Asw, 315 to ∼350 nm) radiation. These experiments also showed that UVR8 and cryptochromes jointly regulate gene expression through interactions that alter the relative sensitivity to UV-B, UV-A, and blue wavelengths. Negative feedback loops on the action of these photoreceptors can arise from gene expression, signaling crosstalk, and absorption of UV photons by phenolic metabolites. These interactions explain why exposure to blue light modulates photomorphogenic responses to UV-B and UV-Asw radiation. Future studies will need to distinguish between short and long wavelengths of UV-A radiation and to consider UVR8’s role as a UV-B/UV-Asw photoreceptor in sunlight.

BTW, "UVR8" stands for "Ultra Violet Resistance Locus 8" – not "UV-B Resistance 8" – look it up.

 

[Rocket Soul]

There is also this:

The photoreceptor UVR8 mediates the perception of both UV-B and UV-A wavelengths up to 350 nm of sunlight with responsivity moderated by cryptochromes

The photoreceptors UV RESISTANCE LOCUS 8 (UVR8) and CRYPTOCHROMES 1 and 2 (CRYs) play major roles in the perception of UV-B (280–315 nm) and UV-A/blue radiation (315–500 nm), respectively. However, it is poorly understood how they function in sunlight. The roles of UVR8 and CRYs were assessed in...

www.biorxiv.org

Uvr8 responsive to light up to 350nm or uva.

Like always the story is a bit more complicated than what it looks. I still stand by that adding uvb is positive, just not the end all uv supplement.

 

[jimihendrix1]

Instead of spamming the same Solacure crap post after post, why don't you answer the questions @Grow Lights Australia asked you?

Surviving, is not the same as thriving. Just because something can carry on, and survive, does not mean it is living in optimal conditions. Just like putting a speaker thats not designed for porting, in a porteed cabinet. It still works, but is not optimal, and may eventually compromise the speaker from excess cone excursion. But it still works. Its just not optimal.

I mispoke when I said 285nm is the only way to trigger the UV8 recepror. I was WRONG!!! . Ill always admit when Im wrong, or mispoke. To do otherwise is ignorant......Supplying light at 285nm IS the most efficient way, and anything past 315nm may affect secondary metabolism, it is not efficient. Although these amounts do increase secondary metabolite production to some extent......They Do Not effectively trigger the UVR8 chemical pathway.

I hate to inform you, the study I showed you has ZERO to do with Solacure Sorry. And I also posted one from the University of Maryland, who didnt use Solacure bulbs. They used a Westinghous FS40 bulb, that was also strong in the 280nm-290nm range.

Westinghouse was the first company to manufacture fluorescent lamps having a phosphor to convert the UV-C to UV-B and UV-A instead of the usual visible light.

I wish I did work for Solacure. All youve got is name calling. Ive never in my life been the first on on an open forum to accuse someone of lying, or shilling for some company. But I will when Ive been called a liar, and a shill.

Its plain to read that the studies say that there is some secondary metabolism in UVA territory, but is not efficient for activation of the UVR8 receptor, and increase secondary metabolite production to some extent

All wavelengths are important, and affect how plants respond to light.
Bulbs that are strongest in the 280-290nm range are made to have the strongest effect on the UVR8 receptor. And Solacure isnt the only one that makes a bulb strong in the 280nm-290nm range.

I also never said 280nm-290nm was the only way to raise THC. I said, well I didnt say the studies said the most efficient way to activate the UVR8 recepeptor was to use both 280nm-290nm of light combined with 385nm of light.

And another study I mention was one NASA did on Skylab in 1973-74 when the experimented on marijuana with Xenon. They determined they could change the chemical profile of the THC by flashing the plants 2x during flowering. The Xenon would slightly burn the plants, and cause the plants to have a chemical response to protect them from these affects.

Xenon has a wavelength of 100-1100nm

What kind of light does a xenon lamp produce?
The electrons drop back to a lower orbit, releasing the energy by producing photons and emitting an intense, very short light pulse. The light produced by the xenon lamps includes broad-spectrum wavelengths from 100 to 1100 nm ( Figure 1 ): UV light (100–400 nm), visible light (400–700 nm), and near-infrared light (700–1100 nm).
Xenon can also be filtered to use for supplemental light for growing plants, and not contain any UVC.

Agromax makes a bulb that is strong in the 280nm-290nm range, Philips makes one. Choose whichever one you like. But both the Philips, and Solacure are T12... I dont care if you use a Solacure, or not The main reason I went with the Solacure is because it it T12, which has a higher physiccal mass, and it has a built in reflector. Thats it. I have zero connection to Solacure, and to say otherwise is lying, and talking out your ass, about things you have no idea about. These bulbs are meant to activate the UVR8 receptor in the most efficient means. They are geared to being a bulb that is geared towards activating this gene in the strongest, most efficient way, and are not meant to be replications of the sun. They are stronger than the sun in the 280nm-290nm range.
Calling people a liar, or accusing them for working with a company of which I have zero affiliation with, only shows me your a punk, who jumps to conclusions.
When you have no argument, attack the messenger. SImple as that.

Shill on dude.

Although these amounts above 315nm do increase secondary metabolite production to some extent, they do not effectively trigger the UVR8 chemical pathway. This specifically requires 280nm to 290nm light. Sounds simple, and straight enough to the point to me.

And its plain to see the the research says that 385nm of light is synergistic to the 280nm-290nm wavelength.

Argue all you want. I couldnt care less. Its plain enough for me to see that the most efficient way to activate UVR8 is to use a wavelength that is strongest from 280nm-290nm, and then also supply secondary wavelength in the 385nm range, along with the wavelength from ither HID, or a good LED, and if possible to include far red. Infrared may also be beneficial. DE HID bulbs are high in Infrared.

There are also studies that say activation of the UVR8 receptor affects several beneficial aspects of the marijuana plant. Not just THC production.

Research has proven that 285 nm UVB triggers the UVR8 pathway, which increases the production of secondary metabolites that mediate many aspects of the interaction of plants with their environment such as acting as feeding deterrents against herbivores, pollinator attractants, protective compounds against pathogens or various abiotic stresses, antioxidants, and signalling molecules.


Increased Production of Specific Secondary Metabolites in Cannabis:

• Cannabinoids
• Terpenoids
• Flavonoids
• Stilbenoids
• Alkaloids
• Lignans

Abiotic Stress - an overview | ScienceDirect Topics

Abiotic Stress - an overview | ScienceDirect Topics

www.sciencedirect.com

1. Abiotic stress responses in plants | Nature Reviews …
   
   

   Abiotic stress responses in plants - Nature Reviews Genetics

   In this Review, Zhang et al. summarize our current understanding of the molecular mechanisms underlying the responses of plants to abiotic stresses, and how this knowledge can be used to improve crop resilience through genetic, chemical and microbial approaches.

   www.nature.com
   Sep 24, 2021 · Abiotic stress conditions, such as high light and osmotic stress, are known to trigger systemic stress signalling in plants,which leads to stress …
   • Author: Huiming Zhang, Jianhua Zhu, Zhizhong Gong, Jian-Kang Zhu
   • Publish Year: 2021

Plant Signaling Molecules | ScienceDirect

www.sciencedirect.com/book/9780128164518/plant-signaling-molecules

Signaling in Plants - Molecular Biology of the Cell - NCBI ...

https://www.ncbi.nlm.nih.gov/books/NBK26895

Signaling in Plants - Molecular Biology of the Cell - NCBI Bookshelf. In plants, as in animals, cells are in constant communication with one another. Plant cells communicate to coordinate their activities in response to the changing conditions of light, dark, and temperature that guide the plant's cycle of growth, flowering, and fruiting.


All of this is activated by triggering the UVR8 reeptor. UVR8 is more important than just THC production.


How UVB Increases THC in Cannabis - Marijuana Grow Shop
marijuanagrow.shop/news/how-uvb-increases-thc-in-cannabis/

A constitutively monomeric UVR8 photoreceptor confers ...

A constitutively monomeric UVR8 photoreceptor confers enhanced UV-B photomorphogenesis - PubMed

The plant ultraviolet-B (UV-B) photoreceptor UVR8 plays an important role in UV-B acclimation and survival. UV-B absorption by homodimeric UVR8 induces its monomerization and interaction with the E3 ubiquitin ligase COP1, leading ultimately to gene expression changes. UVR8 is inactivated through...

pubmed.ncbi.nlm.nih.gov

The plant ultraviolet-B (UV-B) photoreceptor UVR8 plays an important role in UV-B acclimation and survival. UV-B absorption by homodimeric UVR8 induces its monomerization and interaction with the E3 ubiquitin ligase COP1, leading ultimately to gene expression changes. UVR8 is inactivated through redimerization, facilitated by RUP1 and RUP2.

• Cited by: 2
• Publish Year: 2021
• Author: Roman Podolec, Kelvin Ka Ching Lau, Timot

Photochemical reaction mechanism of UV-B-induced ...

Photochemical reaction mechanism of UV-B-induced monomerization of UVR8 dimers as the first signaling event in UV-B-regulated gene expression in plants - PubMed

The Arabidopsis thaliana UV RESISTANCE LOCUS8 (UVR8) protein has been identified to specifically mediate photomorphogenic UV-B responses by acting as a UV-B photoreceptor. The dimeric structure of the UVR8 protein dissociates into signaling-active monomers upon UV-B exposure, and the monomers...

pubmed.ncbi.nlm.nih.gov

Photochemical reaction mechanism of UV-B-induced monomerization of UVR8 dimers as the first signaling event in UV-B-regulated gene expression in plants J Phys Chem B. 2014 Jan 30;118(4):951-65. doi: 10.1021/jp4104118. Epub 2014 Jan 21. Authors ...

• Cited by: 20
• Publish Year: 2014
• Author: Min Wu, Åke Strid, L

Shill on!!!!

 

[jimihendrix1]

1. Q&A: How do plants sense and respond to UV-B radiation ...
   
   

   Q&A: How do plants sense and respond to UV-B radiation? - BMC Biology

   Plants are able to sense UV-B through the UV-B photoreceptor UVR8. UV-B photon absorption by a UVR8 homodimer leads to UVR8 monomerization and interaction with the downstream signaling factor COP1. This then initiates changes in gene expression, which lead to several metabolic and morphological...

   bmcbiol.biomedcentral.com
   Jun 30, 2015 · Abstract. Plants are able to sense UV-B through the UV-B photoreceptor UVR8. UV-B photon absorption by a UVR8 homodimer leads to UVR8 monomerization and interaction with the downstream signaling factor COP1. This then initiates changes in gene expression, which lead to several metabolic and morphological alterations.
   • Cited by: 65
   • Publish Year: 2015
   • Author: Roman Ulm, Gareth I Jenkins
   • Estimated Reading Time: 9 mins

The UVR8 UV-B photoreceptor exists as a homodimer that instantly monomerises upon UV-B absorption via specific intrinsic tryptophans which act as UV-B chromophores.

homodimer is a protein made from two identical proteins

 

[Rocket Soul]

I hate to inform you, the study I showed you has ZERO to do with Solacure Sorry. And I also posted one from the University of Maryland, who didnt use Solacure bulbs. They used a Philips bulb, that was also strong in the 280nm-290nm range.



I wish I did work for Solacure. All youve got is name calling.

Its plain to read that the studies say that there is some secondary metabolism in UVA territory, but is not efficient for activation of the UVR8 receptor, and increase secondary metabolite production to some extent

All wavelengths are important, and affect how plants respond to light.
Bulbs that are strongest in the 280-290nm range are made to have the strongest effect on the UVR8 receptor. And Solacure isnt the only one that makes a bulb strong in the 280nm-290nm range.

Agromax makes one, Philips makes one. Choose whichever one you like. The amain reason I went with the Solacure is because it it T12, and it has a built in reeflector. Thats it. I have zero connection to Solacure, and to say otherwise is llying, and talking out your ass, about things you have no idea about.
Calling people a liar, and accusing them for working with a company of which I have zero affiliation with only dshows me your a punk, who jumps to conclusions.
When you have no argument, attact the messenger. SImple as that.

Shill on dude.

Although these amounts do increase secondary metabolite production to some extent, they do not effectively trigger the UVR8 chemical pathway. This specifically requires 280nm to 290nm light.

And its plain to see the the research says that 385nm of light is synergistic to the 280nm-290nm wavelength.

Argue all you want. I couldnt care less. Its plain enough for me to see that the most efficient way to activate UVR8 is to use a wavelength that is strongest from 280nm-290nm, and then also supply secondary wavelength in the 385nm range, along with the wavelength from ither HID, or a good LED, and if possible to include far red.

Again this does not give any explanation why thc uva > thc uvb in the tests made and referred to in the start of the thread.
Most people are here reading cause of this: how to get higher thc and get more stoned. Not what pathway it takes to get there. Most people would probably be happy to know if they can use uva only, as this would mean using less costly, more reliable and less finnicky (uvb leds tend to bleach the fuck out of top cannopy and can really do a number on your crop).
I still grant that i think adding uvb is a good idea if youre really into it. But i do believe there are easier ways to get higher thc.

 

[jimihendrix1]

There is also a point in mentioning that a fair bit of testing has been done with both gen1 and gen2 of the highlights. Maybe not of full on academic methodology but the results was higher thc in the sample with no uvb, ample +400nm violet, than in the sample with uvb florescent added. This goes quite opposite to what jimi is claiming above and any uv science paper worth its shit should be able to explain this if its claiming that only uvr8 can raise thc.

This is not to say that i am against adding uvb. From what i hear from people tried it theres a definite plus and a change to the better. But i think there is "low hanging fruit" to be reached by adding some uva or violet.

Another thing to mention: why think that uvr8 is the only noteworthy effect of uvb?
Is there any indication that uvr8 is the only thing activated?

I never said only UVB raises THC. I said UVB at 280nm-290nm, combined with strong 385nm is the most efficient way to activate the UVR8 receptor. They work together. 385nm reverses the damage strong UVB elicts.

 

[Grow Lights Australia]

@jimihendrix1 I have asked you politely to stop copy and paste dumping in this thread but you continue to do so. It looks like I am not the only one who is upset at your attempts to derail this thread. If you were posting constructive analysis or individual quotes to support a clear argument then that would be OK but you are not doing that. You are posting the same things over and over again and arguing with people who clearly have experience and knowledge on this subject.

People including myself have asked you some basic questions but you have not answered any of them. I think we can assume that you don't know the answers and that you are copy and pasting as much as you can find on the internet in the hope that this will somehow compensate for your obvious lack of understanding on the subject. You are not being helpful and you are not enlightening anyone. You seem determined only to push the agenda of another company that produces UVB fluorescent bulbs. As a sponsor, it would be hypocritical of me to criticise anyone for posting about their favourite light or growing experience. I also have no issue with anyone criticising any of our products or comparing them to others.

But enough is enough. You have come into this thread and ignored all the discussion and information that was posted earlier about this subject (UVR8, UVB, UVA) and simply copy and pasted a mind-numbingly boring amount of information with no supporting argument and worse, nearly all of it is out of context and most of it appears designed only to sell fluorescent bulbs!

Your behaviour reminds me of an argument I once witnessed between a religious man and a scientist about Darwin's theory of evolution.

Religious man: "See how that swimming pool is the exact same shape as the water inside it? The swimming pool was designed just for that body of water!

Scientist: "See how the water inside that swimming pool conforms to the shape of the pool? The water becomes whatever shape influences it."

In your case I will leave you simply with this: The UVR8 receptor is there because of UVB. UVB is not there because of the UVR8 receptor. Plants grow perfectly well without UVB and some of the strongest cannabis ever grown and recorded was grown indoors without UVB. The receptor is there to protect the plant from different levels of ultra violet, violet and blue light (all of which have enough energy to damage the plant) at different levels and at different wavelengths. That is how nature works. Sunlight is not static and UV levels go up and down. If the UVR8 receptor protected plants only from short wave UVB then it would not protect them against UVA that is equally damaging in larger amounts. If plants did not protect themselves from this UVA that they are exposed to in larger amounts and for much longer periods each day then they would surely perish.

This is something that your cut and paste explosion does not explain. Neither can you explain this in your own words. If you understood even a fraction of the things you have posted then I would not be posting this. But I am now asking you to leave this thread until you can interact properly with people.

Please @jimihendrix1 just go away.