CRYPTOCHROME 1a-mediated blue light perception regulates tomato seed germination via changes in hormonal balance and endosperm-degrading hydrolase dynamics.

MAIN CONCLUSION: Blue light exposure delays tomato seed germination by decreasing endosperm-degrading hydrolase activities, a process regulated by CRY1a-dependent signaling and the hormonal balance between ABA and GA. The germination of tomato seeds (Solanum lycopersicum L.) is tightly controlled by an internal hormonal balance, which is also influenced by environmental factors such as light. In this study, we investigated the blue light (BL)-mediated impacts on physiological, biochemical, and molecular processes during the germination of the blue light photoreceptor CRYPTOCHROME 1a loss-of-function mutant (cry1a) and of the hormonal tomato mutants notabilis (not, deficient in ABA) and procera (pro, displaying a GA-constitutive response). Seeds were germinated in a controlled chamber in the dark and under different intensities of continuous BL (ranging from 1 to 25 µmol m-2 s-1). In general, exposure to BL delayed tomato seed germination in a fluency rate-dependent way due to negative impacts on the activities of endosperm-degrading hydrolases, such as endo-ß-mannanase, ß-mannosidase, and α-galactosidase. However, not and pro mutants presented higher germination speed index (GSI) compared to WT despite the BL influence, associated with higher hydrolase activities, especially evident in pro, indicating that the ABA/GA hormonal balance is important to diminish BL inhibition over tomato germination. The cry1a germination percentage was higher than in WT in the dark but its GSI was lower under BL exposure, suggesting that functional CRY1a is required for BL-dependent germination. BL inhibits the expression of GA-biosynthetic genes, and induces GA-deactivating and ABA-biosynthetic genes. The magnitude of the BL influence over the hormone-related transcriptional profile is also dependent upon CRY1a, highlighting the complex interplay between light and hormonal pathways. These results contribute to a better understanding of BL-induced events behind the photoregulation of tomato seed germination.

Males of Aedes aegypti show different clock gene expression profiles in the presence of conspecific females.

BACKGROUND: The study of behavioral and physiological traits in mosquitoes has been mainly focused on females since males are not hematophagous and thus do not transfer the parasites that cause diseases in human populations. However, the performance of male mosquitoes is key for the expansion of populations and the perpetuation of mosquito species. Pre-copulatory communication between males and females is the initial and essential step for the success of copulation and studying the male facet of this interaction provides fertile ground for the improvement of vector control strategies. Like in most animals, reproduction, feeding, and oviposition are closely associated with locomotor activity in mosquitoes. Rhythmic cycles of locomotor activity have been previously described in Aedes aegypti, and in females, they are known to be altered by blood-feeding and arbovirus infection. In previous work, we found that males in the presence of females significantly change their locomotor activity profiles, with a shift in the phase of the activity peak. Here, we investigated whether this shift is associated with changes in the expression level of three central circadian clock genes. METHODS: Real-time PCR reactions were performed for the gene period, cycle, and cryptochrome 2 in samples of heads, antennae, and abdominal tips of solitary males and males in the presence of females. Assays with antennae-ablated males were also performed, asking whether this is an essential organ mediating the communication and the variation in activity profiles. RESULTS: The gene period showed a conserved expression pattern in all tissues and conditions, while the other two genes varied according to the male condition. A remarking pattern was observed in cry2, where the difference between the amplitude of expression at the beginning of photophase and the expression peak in the scotophase was greater when males were in the presence of females. Antennae ablation in males did not have a significant effect on the expression profiles, suggesting that female recognition may involve other senses besides hearing and olfaction. CONCLUSION: Our results suggest that the expression of gene cryptochrome 2 varies in association with the interaction between males and females.

Overfeeding during development induces temporally-dependent changes in areas controlling food intake in the brains of male Wistar rats.

AIMS: We sought to evaluate the effects of overfeeding during lactation on the feeding behavior and expression of specific regulatory genes in brain areas associated with food intake in 22- and 60-day old male rats. METHODS: We evaluated body weight, food intake of standard and palatable diet, and mRNA expression of dopamine receptor D1 (DDR1), dopamine receptor (DDR2), melanocortin 4 receptor (MC4R), the µ-opioid receptor (MOR), neuropeptide Y (NPY), agouti-related protein (AGRP), proopiomelanocortin (POMC), cocaine-and amphetamine-regulated transcript (CART), serotonin (5-hydroxytryptamine; 5-HT) transporter (SERT), 5-hydroxytryptamine receptor 1B (5-HT1B), 5-hydroxytryptamine receptor 2C receptor (5-HT2C), Clock (CLOK), cryptochrome protein 1 (Cry1) and period circadian protein homolog 2 (Per2) in the striatum, hypothalamus and brainstem of male rats at post-natal days (PND) 22 and 60. KEY FINDINGS: Overfeeding resulted in significantly increased body weight through PND60, and a 2-fold increase in palatable food intake at PND22, but not at PND60. We observed significant increases in DDR1, DDR2, and MC4R gene expression in the striatum and brainstem and POMC/CART in the hypothalamus of the OF group at PND22 that were reversed by PND60. Hypothalamic levels of 5-HT1B, 5-HT2C and NPY/AGRP on the other hand were decreased at PND22 and increased at PND60 in OF animals. Clock genes were unaffected by OF at PND22, but were significantly elevated at PND60. SIGNIFICANCE: Overfeeding during early development of the rat brain results in obesity and altered feeding behavior in early adulthood. The altered behavior might be the consequence of the changes in food intake and reward gene expression.

Cryptochrome 1a depends on blue light fluence rate to mediate osmotic stress responses in tomato.

The participation of plant cryptochromes in water deficit response mechanisms has been highlighted in several reports. However, the role of tomato (Solanum lycopersicum L.) cryptochrome 1a (cry1a) in the blue light fluence-dependent modulation of the water deficit response remains largely elusive. The tomato cry1a mutant and its wild-type counterpart were grown in water (no stress) or PEG6000 (osmotic stress) treatments under white light (60 µmol m-2 s-1) or from low to high blue light fluence (1, 5, 10, 15 and 25 µmol m-2 s-1). We first demonstrate that under nonstress conditions cry1a regulates seedling growth by mechanisms that involve pigmentation, lipid peroxidation and osmoprotectant accumulation in a blue light-dependent manner. In addition, we further highlighted under osmotic stress conditions that cry1a increased tomato growth by reduced malondialdehyde (MDA) and proline accumulation. Although blue light is an environmental signal that influences osmotic stress responses mediated by tomato cry1a, specific blue light fluence rates are required during these responses. Here, we show that CRY1a manipulation may be a potential biotechnological target to develop a drought-tolerant tomato variety. Nevertheless, the complete understanding of this phenomenon requires further investigation.

Cryptochrome 1a of tomato mediates long-distance signaling of soil water deficit.

Although the blue light photoreceptors cryptochromes mediate the expression of genes related to reactive oxygen species, whether cryptochrome 1a (cry1a) regulates local and long-distance signaling of water deficit in tomato (Solanum lycopersicum L.) is unknown. Thus the cry1a tomato mutant and its wild-type (WT) were reciprocally grafted (WT/WT; cry1a/cry1a; WT/cry1a; cry1a/WT; as scion/rootstock) or grown on their own roots (WT and cry1a) under irrigated and water deficit conditions. Plant growth, pigmentation, oxidative stress, water relations, stomatal characteristics and leaf gas exchange were measured. WT and cry1a plants grew similarly under irrigated conditions, whereas cry1a plants had less root biomass and length and higher tissue malondialdehyde concentrations under water deficit. Despite greater oxidative stress, cry1a maintained chlorophyll and carotenoid concentrations in drying soil. Lower stomatal density of cry1a likely increased its leaf relative water content (RWC). In grafted plants, scion genotype largely determined shoot and root biomass accumulation irrespective of water deficit. In chimeric plants grown in drying soil, cry1a rootstocks increased RWC while WT rootstocks maintained photosynthesis of cry1a scions. Manipulating tomato CRY1a may enhance plant drought tolerance by altering leaf pigmentation and gas exchange during soil drying via local and long-distance effects.

Photolyases and Cryptochromes in UV-resistant Bacteria from High-altitude Andean Lakes.

"High-altitude Andean Lakes" (HAAL) are pristine environments harboring poly-extremophilic microbes that show combined adaptations to physical and chemical stress such as large daily ambient thermal amplitude, extreme solar radiation levels, intense dryness, alkalinity, high concentrations of arsenic (up to 200 ppm) and dissolved salts. In this work, we compared the UV resistance profiles, pigment content and photoreactivation abilities of three UV-resistant bacteria isolated from distinct niches from HAALs, that is Acinetobacter sp. Ver3 (water, Lake Verde; 4400 m), Exiguobacterium sp. S17 (stromatolite, Lake Socompa, 3570 m) and Nesterenkonia sp. Act20 (soil, Lake Socompa, 3570 m). UV resistance ability of HAAL's strains indicate a clear adaptation to high radiation exposure encountered in their original habitat, which can be explained by genetic and physiological mechanisms named as the UV-resistome. Thus, the UV-resistome depends on the expression of a diverse set of genes devoted to evading or repairing the damage it provoked direct or indirectly. As pigment extraction and photoreactive assays indicate the presence of photoactive molecules, we characterized more in detail proteins with homology to photolyases/cryptochromes members (CPF). Phylogenetic analyses, sequence comparison and 3D modeling with bona fide CPF members were used to prove the presence of functional domains and key residues in the novel proteins.

Long-Day Photoperiod Enhances Jasmonic Acid-Related Plant Defense.

Agricultural crops are exposed to a range of daylengths, which act as important environmental cues for the control of developmental processes such as flowering. To explore the additional effects of daylength on plant function, we investigated the transcriptome of Arabidopsis (Arabidopsis thaliana) plants grown under short days (SD) and transferred to long days (LD). Compared with that under SD, the LD transcriptome was enriched in genes involved in jasmonic acid-dependent systemic resistance. Many of these genes exhibited impaired expression induction under LD in the phytochrome A (phyA), cryptochrome 1 (cry1), and cry2 triple photoreceptor mutant. Compared with that under SD, LD enhanced plant resistance to the necrotrophic fungus Botrytis cinerea This response was reduced in the phyA cry1 cry2 triple mutant, in the constitutive photomorphogenic1 (cop1) mutant, in the myc2 mutant, and in mutants impaired in DELLA function. Plants grown under SD had an increased nuclear abundance of COP1 and decreased DELLA abundance, the latter of which was dependent on COP1. We conclude that growth under LD enhances plant defense by reducing COP1 activity and enhancing DELLA abundance and MYC2 expression.

Circadian rhythms of factors involved in luteal regression are modified in p55 tumour necrosis factor receptor (TNFRp55)-deficient mice.

The rhythm of factors involved in luteal regression is crucial in determining the physiological duration of the oestrous cycle. Given the role of tumour necrosis factor (TNF)-α in luteal function and circadian regulation and that most of the effects of TNF-α are mediated by p55 TNF receptor (TNFRp55), the aims of the present study were to analyse the following during the luteal regression phase in the ovary of mice: (1) whether the pattern of expression of progesterone (P4) and the enzymes involved in the synthesis and degradation of P4 is circadian and endogenous (the rhythm persists in constant conditions, (i.e., constant darkness) with a period of about 24 hours); (2) circadian oscillations in clock gene expression; (3) whether there are daily variations in the expression of key genes involved in apoptosis and antioxidant mechanisms; and (4) the consequences of TNFRp55 deficiency. P4 was found to oscillate circadianally following endogenous rhythms of clock factors. Of note, TNFRp55 deficiency modified the circadian oscillation in P4 concentrations and its enzymes involved in the synthesis and degradation of P4, probably as a consequence of changes in the circadian oscillations of brain and muscle ARNT-Like protein 1 (Bmal1) and Cryptochrome 1 (Cry1). Furthermore, TNFRp55 deficiency modified the circadian rhythms of apoptosis genes, as well as antioxidant enzymes and peroxidation levels in the ovary in dioestrus. The findings of the present study strengthen the hypothesis that dysregulation of TNF-α signalling may be a potential cause for altered circadian and menstrual cycling in some gynaecological diseases.

Structural disorder in plant proteins: where plasticity meets sessility.

Plants are sessile organisms. This intriguing nature provokes the question of how they survive despite the continual perturbations caused by their constantly changing environment. The large amount of knowledge accumulated to date demonstrates the fascinating dynamic and plastic mechanisms, which underpin the diverse strategies selected in plants in response to the fluctuating environment. This phenotypic plasticity requires an efficient integration of external cues to their growth and developmental programs that can only be achieved through the dynamic and interactive coordination of various signaling networks. Given the versatility of intrinsic structural disorder within proteins, this feature appears as one of the leading characters of such complex functional circuits, critical for plant adaptation and survival in their wild habitats. In this review, we present information of those intrinsically disordered proteins (IDPs) from plants for which their high level of predicted structural disorder has been correlated with a particular function, or where there is experimental evidence linking this structural feature with its protein function. Using examples of plant IDPs involved in the control of cell cycle, metabolism, hormonal signaling and regulation of gene expression, development and responses to stress, we demonstrate the critical importance of IDPs throughout the life of the plant.

Dexamethasone Modulates Nonvisual Opsins, Glucocorticoid Receptor, and Clock Genes in Danio rerio ZEM-2S Cells.

Here we report, for the first time, the differential cellular distribution of two melanopsins (Opn4m1 and Opn4m2) and the effects of GR agonist, dexamethasone, on the expression of these opsins and clock genes, in the photosensitive D. rerio ZEM-2S embryonic cells. Immunopositive labeling for Opn4m1 was detected in the cell membrane whereas Opn4m2 labeling shows nuclear localization, which did not change in response to light. opn4m1, opn4m2, gr, per1b, and cry1b presented an oscillatory profile of expression in LD condition. In both DD and LD condition, dexamethasone (DEX) treatment shifted the peak expression of per1b and cry1b transcripts to ZT16, which corresponds to the highest opn4m1 expression. Interestingly, DEX promoted an increase of per1b expression when applied in LD condition but a decrease when the cells were kept under DD condition. Although DEX effects are divergent with different light conditions, the response resulted in clock synchronization in all cases. Taken together, these data demonstrate that D. rerio ZEM-2S cells possess a photosensitive system due to melanopsin expression which results in an oscillatory profile of clock genes in response to LD cycle. Moreover, we provide evidence that glucocorticoid acts as a circadian regulator of D. rerio peripheral clocks.

The Trichoderma atroviride cryptochrome/photolyase genes regulate the expression of blr1-independent genes both in red and blue light.

Quantitative transcriptome analysis led to the identification of 331 transcripts regulated by white light. Evaluation of the response to white light in mutants affected in the previously characterized blue-light receptor Blr1, demonstrated the existence of both Blr1-dependent and independent responses. Functional categorization of the light responsive genes indicated the effect of light on regulation of various transcription factors, regulators of chromatin structure, signaling pathways, genes related to different kinds of stress, metabolism, redox adjustment, and cell cycle among others. In order to establish the participation of other photoreceptors, gene expression was validated in response to different wavelengths. Gene regulation by blue and red light suggests the involvement of several photoreceptors in integrating light signals of different wavelengths in Trichoderma atroviride. Functional analysis of potential blue light photoreceptors suggests that several perception systems for different wavelengths are involved in the response to light. Deletion of cry1, one of the potential photoreceptors, resulted in severe reduction in the photoreactivation capacity of the fungus, as well as a change in gene expression under blue and red light.

Historia de los terrenos del Hospital Clínico y la Facultad de Medicina de la Universidad de Chile / History of the University of Chile Faculty of Medicine and clinical hospital location

The history of the location of the University of Chile Faculty of Medicine North Campus is derived from a farm of Pedro de Valdivia founder of the city of Santiago de la Nueva Extremadura and governor of the “Reyno de Chile”. This work narrates succinctly the history of this particular location from the Spanish Conquest period to present days.

From blue light to clock genes in zebrafish ZEM-2S cells.

Melanopsin has been implicated in the mammalian photoentrainment by blue light. This photopigment, which maximally absorbs light at wavelengths between 470 and 480 nm depending on the species, is found in the retina of all classes of vertebrates so far studied. In mammals, melanopsin activation triggers a signaling pathway which resets the circadian clock in the suprachiasmatic nucleus (SCN). Unlike mammals, Drosophila melanogaster and Danio rerio do not rely only on their eyes to perceive light, in fact their whole body may be capable of detecting light and entraining their circadian clock. Melanopsin, teleost multiple tissue (tmt) opsin and others such as neuropsin and va-opsin, are found in the peripheral tissues of Danio rerio, however, there are limited data concerning the photopigment/s or the signaling pathway/s directly involved in light detection. Here, we demonstrate that melanopsin is a strong candidate to mediate synchronization of zebrafish cells. The deduced amino acid sequence of melanopsin, although being a vertebrate opsin, is more similar to invertebrate than vertebrate photopigments, and melanopsin photostimulation triggers the phosphoinositide pathway through activation of a G(q/11)-type G protein. We stimulated cultured ZEM-2S cells with blue light at wavelengths consistent with melanopsin maximal absorption, and evaluated the time course expression of per1b, cry1b, per2 and cry1a. Using quantitative PCR, we showed that blue light is capable of slightly modulating per1b and cry1b genes, and drastically increasing per2 and cry1a expression. Pharmacological assays indicated that per2 and cry1a responses to blue light are evoked through the activation of the phosphoinositide pathway, which crosstalks with nitric oxide (NO) and mitogen activated protein MAP kinase (MAPK) to activate the clock genes. Our results suggest that melanopsin may be important in mediating the photoresponse in Danio rerio ZEM-2S cells, and provide new insights about the modulation of clock genes in peripheral clocks.

Temporal modulation of the canonical clockwork in the suprachiasmatic nucleus and olfactory bulb by the mammary pheromone 2MB2 in pre-visual rabbits.

During the early stages of development, the olfactory system plays a vital role in the survival of altricial mammals. One remarkable example is the Oryctolagus cuniculus, whose mother-young interaction greatly depends on the 2-methylbut-2-enal (2MB2) pheromone that triggers nipple search and grasping behaviors. Olfactory stimulation with 2MB2 regulates the expression of the core body temperature and locomotor activity rhythms in rabbit pups, indicating the modulation of the circadian system by this volatile cue. To address this issue, in the present study, we determined the effect of stimulation with pulses of 2MB2 on the molecular circadian clockwork in the suprachiasmatic nucleus (SCN) and in the main olfactory bulb (MOB). For this purpose, 7-day-old rabbits were stimulated with distilled water (CON), with ethyl isobutyrate (ETHYL) or with the pheromone (2MB2) at different times of the cycle, and 1h later, the expression of the activity marker C-FOS and of the clock proteins PER1, CRY1 and BMAL1 was evaluated in the SCN and in the three layers of the MOB. The clock proteins were abundantly expressed in both structures; nevertheless these showed diurnal rhythmicity only in the MOB, confirming that central pacemakers exhibit a heterochronical development of the molecular clockwork. C-FOS expression in the SCN and in the MOB was modulated by exposure to ETHYL and to 2MB2 only when these stimulants were presented at ZT00 and at ZT18. In contrast, the clock proteins were essentially modulated by 2MB2 at ZT00 and at ZT06 in both structures. In addition, the PER1 and CRY1 proteins exhibited differential responses to stimulation in the three layers of the MOB. For the first time, we report a modulatory and time-dependent effect of the mammary pheromone 2MB2 on the expression of the core clock proteins in the SCN and in the MOB in rabbits during pre-visual stages of development.

The in vitro maintenance of clock genes expression within the rat pineal gland under standard and norepinephrine-synchronized stimulation.

Although the norepinephrine (NE) synchronization protocol was proved to be an important procedure for further modulating in vitro pineal melatonin synthesis, the maintenance of clock genes under the same conditions remained to be investigated. The aim of this study was to investigate the maintenance of the clock genes expression in pineal gland cultures under standard and NE-synchronized stimulation. The glands were separated into three experimental groups: Control, Standard (acute NE-stimulation), and NE-synchronized. The expression of Bmal1, Per2, Cry2, Rev-erbα, the clock controlled gene Dbp and Arylalkylamine-N-acetyltransferase were investigated, as well as melatonin content. No oscillations were observed in the expression of the investigated genes from the control group. Under Standard NE stimulation, the clock genes did not exhibit a rhythmic pattern of expression. However, in the NE-synchronized condition, a rhythmic expression pattern was observed in all cases. An enhancement in pineal gland responsiveness to NE stimulation, reflected in an advanced synthesis of melatonin was also observed. Our results reinforce our previous hypothesis that NE synchronization of pineal gland culture mimics the natural rhythmic release of NE in the gland, increasing melatonin synthesis and keeping the pineal circadian clock synchronized, ensuring the fine adjustments that are relied in the clockwork machinery.

ROS signaling pathways and biological rhythms: perspectives in crustaceans.

This work reviews concepts regarding the endogenous circadian clock and the relationship between oxidative stress (OS), light and entrainment in different organisms including crustaceans, particularly crayfish. In the first section, the molecular control of circadian rhythms in invertebrates, particularly in Drosophila, is reviewed, and this model is contrasted with recent reports on the circadian genes and proteins in crayfish. Second, the redox mechanisms and signaling pathways that participate in the entrainment of the circadian clock in different organisms are reviewed. Finally, the light signals and transduction pathways involved in the entrainment of the circadian clock, specifically in relation to cryptochromes (CRYs) and their dual role in the circadian clock of different animal groups and their possible relationship to the circadian clock and redox mechanisms in crustaceans is discussed. The relationship between metabolism, ROS signals and transcription factors, such as HIF-1 alpha in crayfish, as well as the possibility that HIF-1 alpha participates in the regulation of circadian control genes (ccgs) in crustaceans is discussed.

cry1 and GPA1 signaling genetically interact in hook opening and anthocyanin synthesis in Arabidopsis.

While studying blue light-independent effects of cryptochrome 1 (cry1) photoreceptor, we observed premature opening of the hook in cry1 mutants grown in complete darkness, a phenotype that resembles the one described for the heterotrimeric G-protein α subunit (GPA1) null mutant gpa1. Both cry1 and gpa1 also showed reduced accumulation of anthocyanin under blue light. These convergent gpa1 and cry1 phenotypes required the presence of sucrose in the growth media and were not additive in the cry1 gpa1 double mutant, suggesting context-dependent signaling convergence between cry1 and GPA1 signaling pathways. Both, gpa1 and cry1 mutants showed reduced GTP-binding activity. The cry1 mutant showed wild-type levels of GPA1 mRNA or GPA1 protein. However, an anti-transducin antibody (AS/7) typically used for plant Gα proteins, recognized a 54 kDa band in the wild type but not in gpa1 and cry1 mutants. We propose a model where cry1-mediated post-translational modification of GPA1 alters its GTP-binding activity.

The cyclophilin ROC1 links phytochrome and cryptochrome to brassinosteroid sensitivity.

Although multiple photoreceptors converge to control common aspects of seedling de-etiolation, we are relatively ignorant of the genes acting at or downstream of their signalling convergence. To address this issue we screened for mutants under a mixture of blue plus far-red light and identified roc1-1D. The roc1-1D mutant, showing elevated expression of the ROTAMASE CYCLOPHILIN 1 (ROC1/AtCYP18-3) gene, and partial loss-of function roc1 alleles, has defects in phytochrome A (phyA)-, cryptochrome 1 (cry1)- and phytochrome B (phyB)-mediated de-etiolation, including long hypocotyls under blue or far-red light. These mutants show elevated sensitivity to brassinosteroids in the light but not in the dark. Mutations at brassinosteroid signalling genes and the application of a brassinosteroid synthesis inhibitor eliminated the roc1 and roc1-D phenotypes. The roc1 and roc1-D mutants show altered patterns of phosphorylation of the transcription factor BES1, a known point of control of sensitivity to brassinosteroids, which correlate with the expression levels of genes directly targeted by BES1. We propose a model where perception of light by phyA, cry1 or phyB activates ROC1 (at least in part by enhancing its expression). This in turn reduces the intensity of brassinosteroid signalling and fine-tunes seedling de-etiolation.

Expression of clock genes in human subcutaneous and visceral adipose tissues.

Disrupted circadian rhythms are associated with obesity and metabolic alterations, but little is known about the participation of peripheral circadian clock machinery in these processes. The aim of the present study was to analyze RNA expression of clock genes in subcutaneous (SAT) and visceral (VAT) adipose tissues of male and female subjects in AM (morning) and PM (afternoon) periods, and its interactions with body mass index (BMI). Ninety-one subjects (41 ± 11 yrs of age) presenting a wide range of BMI (21.4 to 48.6 kg/m(2)) were included. SAT and VAT biopsies were obtained from patients undergoing abdominal surgeries. Clock genes expressions were evaluated by qRT-PCR. The only clock gene that showed higher expression (p < .0001) in SAT in comparison to VAT was PER1 of female (372%) and male (326%) subjects. Different patterns of expression between the AM and PM periods were observed, in particular REV-ERBα, which was reduced (p < .05) at the PM period in SAT and VAT of both women and men (women: ∼53% lower; men: ∼78% lower), whereas CLOCK expression was not altered. Relationships between clock genes were different in SAT vs. VAT. BMI was negatively correlated with SATPER1 (r = -.549; p = .001) and SATPER2 (r = -.613; p = .0001) and positively with VATCLOCK (r = .541; p = .001) and VATBMAL1 (r = .468; p = .007) only in women. These data suggest that the circadian clock machinery of adipose tissue depots differs between female and male subjects, with a sex-specific effect observed for some genes. BMI correlated with clock genes, but at this moment it is not possible to establish the cause-effect relationship.

Phototropins but not cryptochromes mediate the blue light-specific promotion of stomatal conductance, while both enhance photosynthesis and transpiration under full sunlight.

Leaf epidermal peels of Arabidopsis (Arabidopsis thaliana) mutants lacking either phototropins 1 and 2 (phot1 and phot2) or cryptochromes 1 and 2 (cry1 and cry2) exposed to a background of red light show severely impaired stomatal opening responses to blue light. Since phot and cry are UV-A/blue light photoreceptors, they may be involved in the perception of the blue light-specific signal that induces the aperture of the stomatal pores. In leaf epidermal peels, the blue light-specific effect saturates at low irradiances; therefore, it is considered to operate mainly under the low irradiance of dawn, dusk, or deep canopies. Conversely, we show that both phot1 phot2 and cry1 cry2 have reduced stomatal conductance, transpiration, and photosynthesis, particularly under the high irradiance of full sunlight at midday. These mutants show compromised responses of stomatal conductance to irradiance. However, the effects of phot and cry on photosynthesis were largely nonstomatic. While the stomatal conductance phenotype of phot1 phot2 was blue light specific, cry1 cry2 showed reduced stomatal conductance not only in response to blue light, but also in response to red light. The levels of abscisic acid were elevated in cry1 cry2. We conclude that considering their effects at high irradiances cry and phot are critical for the control of transpiration and photosynthesis rates in the field. The effects of cry on stomatal conductance are largely indirect and involve the control of abscisic acid levels.