Shortened temperature‐relevant period of spring leaf‐out in temperate‐zone trees

Temperature during a particular period prior to spring leaf‐out, the temperature‐relevant period (TRP), is a strong determinant of the leaf‐out date in temperate‐zone trees. Climatic warming has substantially advanced leaf‐out dates in temperate biomes worldwide, but its effect on the beginning and length of the TRP has not yet been explored, despite its direct relevance for phenology modeling. Using 1,551 species–site combinations of long‐term (1951–2016) in situ observations on six tree species (namely, Aesculus hippocastanum, Alnus glutinosa, Betula pendula, Fagus sylvatica, Fraxinus excelsior, and Quercus robur) in central Europe, we found that the advancing leaf‐out was accompanied by a shortening of the TRP. On average across all species and sites, the length of the TRP significantly decreased by 23% (p < .05), from 60 ± 4 days during 1951–1965 to 47 ± 4 days during 2002–2016. Importantly, the average start date of the TRP did not vary significantly over the study period (March 2–5, DOY = 61–64), which could be explained by sufficient chilling over the study period in the regions considered. The advanced leaf‐out date with unchanged beginning of the TRP can be explained by the faster accumulation of the required heat due to climatic warming, which overcompensated for the retarding effect of shortening daylength on bud development. This study shows that climate warming has not yet affected the mean TRP starting date in the study region, implying that phenology modules in global land surface models might be reliable assuming a fixed TRP starting date at least for the temperate central Europe. Field warming experiments do, however, remain necessary to test to what extent the length of TRP will continue to shorten and whether the starting date will remain stable under future climate conditions.     

Agonistic trials with mirrors do not elicit the same aggressiveness of a real trial in the matrinxã fish,Brycon amazonicus (Spix & Agassiz, 1829)

This study tested the efficacy of mirror trials in studying aggressiveness in the matrinxã fish, Brycon amazonicus. The hypothesis was that a mirror would elicit an aggressive response in B. amazonicus juveniles, but show different behavioral and physiological profiles than those observed in trials with real opponents. Fish were tested using either a mirror trial (n = 7) or a real trial (n = 7), that is, placed alone with a mirror or paired with a same‐sized opponent, respectively. All trials lasted for 20 min and took place in 96‐L aquaria with water temperatures of 28°C. Fish in mirror trials exhibited less locomotion (mirror: 423.3 ± 39.1; real trial: 735.1 ± 31.9; p < .001), rushed less against the opponent (mirror: 3.1 ± 2.3; real trial: 39.6 ± 5.1; p < .001) and showed less escalation of aggressive behavior compared to the winner of a real trial. Regarding the physiological parameters, despite similar cortisol responses (mirror: 84.2 ± 13.8 ng/ml; real trial: 77.2 ± 16.9 ng/ml; p = .757), the fish that fought against a mirror had lower levels of plasma glucose than those of fish that fought against a real opponent (mirror: 76.8 ± 3.6 ng/dl; real trial: 103.8 ± 10.1 ng/ml; p = .037). This lower energy mobilization might be due to a lower cost of the fight in the absence of an opponent that flees from attacks, as the locomotion and number of rush totals were also lower in the mirror trials. This pattern of less locomotion is probably common in mirror trials because the opponent is always limited to one side of the arena. If the energetic cost is one of the factors that can determine the outcome of a fight, and if mirror trials do not evoke the physiological response observed in a real fight, the use of mirror trials must be reviewed in studies that consider the physiological responses.     

Kisspeptin1 modulates odorant‐evoked fear response via two serotonin receptor subtypes (5‐HT1A and 5‐HT2) in zebrafish

Kiss1, a neuropeptide predominantly expressed in the habenula, modulates the serotonin (5‐HT) system to decrease odorant cue [alarm substance (AS)]‐evoked fear behaviour in the zebrafish. The purpose of this study was to assess the interaction of Kiss1 with the 5‐HT system as well as to determine the involvement of the 5‐HT receptor subtypes in AS‐evoked fear. We utilized 0. 28 mg/kg WAY 100635 (WAY), a selective 5‐HT_1A receptor antagonist, to observe the effects of Kiss1 administration on AS‐evoked fear. We found WAY significantly inhibited the anxiolytic effects of Kiss1 (p < 0.001) with an exception of freezing behaviour. Based on this, we utilized 92.79 mg/kg methysergide, a 5‐HT₁ and 5‐HT₂ receptor antagonist, and found that methysergide significantly blocked the anxiolytic effects of Kiss1 in the presence of the AS (p < 0.001). From this, we conclude that Kiss1 modulates AS‐evoked fear responses mediated by the 5‐HT_1A and 5‐HT₂ receptors.

     

Scheduled feeding versus the light-dark cycle on the rhythms of circulating tryptophan, serotonin and N-acetylserotonin in rats

Both the environmental light-dark cycle and scheduled feeding can act as entrainers of biological rhythms. The present study investigated the relative potency of these two environmental cues in entraining the rhythms of circulating tryptophan (TRP), serotonin (5HT) and N-acetylserotonin (NAS). Four groups of rats were subjected for one month to an identical light-dark cycle of 14 h light and 10 h dark with food availability restricted to the 3 h period beginning 2 h after onset of light or onset of darkness. Two groups of animals were food deprived on the day of experiment. The 24 h rhythms of serum TRP, 5HT and NAS were determined. Serum TRP showed a sharp increase after food presentation and declined gradually to a trough just before feeding. Withholding food on the day of experiment abolished this increase. The trough of serum 5HT occurred just before feeding, increased gradually after feeding and peaked 10-13 h afterwards. Serum NAS levels, however, demonstrated an anticipatory rise before feeding, which peaked during feeding and declined to a trough 8 h afterwards. Unlike TRP, withholding food had no effect on either the 5HT or the NAS rhythm. These results indicated that feeding schedule was the common and stronger entrainer for the rhythms of serum TRP, 5HT and NAS. However, each indole had a different rhythm pattern in relation to the feeding schedule which could not be explained by a simple precursor-product relationship.     

Association of dopamine‐ and serotonin‐related genes with canine aggression

Human‐directed canine aggression was studied using 50 aggressive and 81 non‐aggressive dogs. We examined 62 single nucleotide polymorphisms (SNPs) occurring in or in the close vicinity of 16 neurotransmitter‐related genes. Allelic associations with aggression were identified for DRD1, HTR1D, HTR2C and SLC6A1. Risk or protective haplotypes for aggressive behaviour based on 2–5 SNPs were identified. The frequency of aggressive dogs varied significantly between the haplotypes within loci and the odds ratios of aggression in dogs with risk haplotypes compared with protective haplotypes varied from 4.4 (HTR2C) to 9.0 (SLC6A1). A risk haplotype across the neurotransmitter receptor gene HTR1D harboured a non‐synonymous SNP with a potential effect on protein function. We identified no haplotypes in complete association with the recorded phenotypes, supporting a complex inheritance of aggression.     

Effects of dietary l-tryptophan and lighting conditions on growth performance of European sea bass (Dicentrarchus labrax) juveniles reared in a recirculating water system

The aim of the present study was to investigate possible stressful effects on European sea bass Dicentrarchus labrax reared under constant darkness (0L‐24D) and to examine the possible anti‐stressful effect of dietary tryptophan (TRP) supplementation. Juvenile European sea bass (initial body weight 4.23 ± 0.032 g) were reared for 10 weeks under 0L‐24D and 12L‐12D and fed either a commercial diet (0.47% TRP) or the same diet supplemented with L‐TRP (2.47% TRP). Results showed that lighting conditions had no significant effect on fish growth, while a depressive effect by the TRP supplementation was obvious. All fish populations reared under 0L‐24D exhibited reduced body protein, lipid and ash content and increased food consumption. Reduced body lipids, food consumption and nutrient utilization were observed in TRP‐supplemented fed fish, along with lower liver lipids. Dietary TRP enrichment significantly lowered liver saturated and monounsaturated acids and increased poly‐ and highly‐unsaturated fatty acids, especially in combination with 0L‐24D. These changes were also considerably reflected in carcass fatty acid composition.     

Mutant Alleles at the Brown Locus Encoding Tyrosinase‐Related Protein‐1 (TRP‐1) Affect Proliferation of Mouse Melanocytes in Culture *

Tyrosinase related protein‐1 (TRP‐1) is a melanocyte‐specific gene product involved in eumelanin synthesis. Mutation in the Tyrp1 gene is associated with brown pelage in mouse and oculocutaneous albinism Type 3 in humans (OCA3). It has been demonstrated that TRP‐1 expresses DHICA oxidase activity in the murine system. However, its actual function in the human system is still unclear. The study was designed to determine the effects of mutation at two Typr1 alleles, namely the Tyrp1^b (brown) and Tyrp1^b‐cj (cordovan) compared with wild type Tyrp1^B (black) on melanocyte function and melanin biosynthesis. The most significant finding was that both of the Tyrp1 mutations (i.e. brown expressing a point mutation and cordovan expressing decreased amount of TRP‐1 protein) resulted in attenuation of cell proliferation rates. Neither necrosis nor apoptosis was responsible for the observed decrease in cell proliferation rates of the brown and cordovan melanocytes. Ultrastructural evaluation by electron microscopic analysis revealed that both mutations in Tyrp1 affected melanosome maturation without affecting its structure. These observations demonstrate that mutation in Tyrp1 compromised tyrosinase activity within the organelle. DOPA histochemistry revealed differences in melanosomal stages between black and brown melanocytes but not between black and cordovan melanocytes. There were no significant differences in tyrosine hydroxylase activities of tyrosinase and TRP‐1 in wild type black, brown and cordovan melanocyte cell lysates. We conclude that mutations in Tyrp1 compromise cell proliferation and melanosomal maturation in mouse melanocyte cultures.     

Intra‐Molecular Donor–Acceptor Interaction Effects on Charge Dissociation,Charge Transport,and Charge Collection in Bulk‐Heterojunction Organic Solar Cells

This article reports experimental studies on internal charge dissociation, transport, and collection by using magnetic field effects of photocurrent (MFE_PC) and light‐assisted dielectric response (LADR) in highly‐efficient organic solar cells based on photovoltaic polymer PTB2 and PTB4 with intra‐molecular “donor–acceptor” interaction. The MFE_PC at low‐field (< 150 mT) indicates that intra‐molecular “donor‐acceptor” interaction generates charge dissociation in un‐doped PTB2 and PTB4 films, which is similar to that in lightly doped P3HT (Poly(3‐hexylthiophene)) with 5 wt% PCBM (1‐(3‐methyloxycarbonyl)‐propyl‐1‐phenyl (6,6) C₆₁). After PTB2 and PTB4 are mixed with PCBM to form bulk‐heterojunctions, the MFE_PC at high‐field (> 150 mT) reveals that the charge‐transfer complexes formed at PTB2:PCBM and PTB4:PCBM interfaces have much lower binding energies due to stronger electron‐withdrawing abilities, as compared to the P3HT:PCBM device, towards the generation of photocurrent. Furthermore, the light‐assisted dielectric response: LADR indicates that the PTB2:PCBM and PTB4:PCBM solar cells exhibit larger capacitances relative to P3HT:PCBM device under photoexcitation. This reflects that the PTB2:PCBM and PTB4:PCBM bulk heterojunctions have more effective charge transport and collection than the P3HT:PCBM counterpart. As a result, our experimental results indicate that intra‐molecular “donor‐acceptor” interaction plays an important role to enhance charge dissociation, transport, and collection in bulk‐heterojunction organic solar cells.     

Effects of yogurt and bifidobacteria supplementation on the colonic microbiota in lactose-intolerant subjects

Aims: Colonic metabolism of lactose may play a role in lactose intolerance. We investigated whether a 2‐week supplementation of Bifidobacterium longum (in capsules) and a yogurt enriched with Bifidobacterium animalis could modify the composition and metabolic activities of the colonic microbiota in 11 Chinese lactose‐intolerant subjects. Methods and Results: The numbers of total cells, total bacteria and the Eubacterium rectale/Clostridium coccoides group in faeces as measured with fluorescent in situ hybridization and the faecal β‐galactosidase activity increased significantly during supplementation. The number of Bifidobacterium showed a tendency to increase during and after supplementation. With PCR‐denaturing gradient gel electrophoresis, in subjects in which B. animalis and B. longum were not detected before supplementation, both strains were present in faeces during supplementation, but disappeared after supplementation. The degree of lactose digestion in the small intestine and the oro‐caecal transit time were not different before and after supplementation, whereas symptom scores after lactose challenge decreased after supplementation. Conclusions: The results suggest that supplementation modifies the amount and metabolic activities of the colonic microbiota and alleviates symptoms in lactose‐intolerant subjects. The changes in the colonic microbiota might be among the factors modified by the supplementation which lead to the alleviation of lactose intolerance. Significance and Impact of the Study: This study provides evidence for the possibility of managing lactose intolerance with dietary lactose (yogurt) and probiotics via modulating the colonic microbiota.     

V‐ATPase deactivation in blowfly salivary glands is mediated by protein phosphatase 2C

The activity of vacuolar H⁺‐ATPase (V‐ATPase) in the apical membrane of blowfly (Calliphora vicina) salivary glands is regulated by the neurohormone serotonin (5‐HT). 5‐HT induces, via protein kinase A, the phosphorylation of V‐ATPase subunit C and the assembly of V‐ATPase holoenzymes. The protein phosphatase responsible for the dephosphorylation of subunit C and V‐ATPase inactivation is not as yet known. We show here that inhibitors of protein phosphatases PP1 and PP2A (tautomycin, ocadaic acid) and PP2B (cyclosporin A, FK‐506) do not prevent V‐ATPase deactivation and dephosphorylation of subunit C. A decrease in the intracellular Mg²⁺ level caused by loading secretory cells with EDTA‐AM leads to the activation of proton pumping in the absence of 5‐HT, prolongs the 5‐HT‐induced response in proton pumping, and inhibits the dephosphorylation of subunit C. Thus, the deactivation of V‐ATPase is most probably mediated by a protein phosphatase that is insensitive to okadaic acid and that requires Mg²⁺, namely, a member of the PP2C protein family. By molecular biological techniques, we demonstrate the expression of at least two PP2C protein family members in blowfly salivary glands. © 2009 Wiley Periodicals, Inc.     

Nociceptive transient receptor potential canonical 7 (TRPC7) mediates aging‐associated tumorigenesis induced by ultraviolet B

Aging, cancer, and longevity have been linked to intracellular Ca²⁺ signaling and nociceptive transient receptor potential (TRP) channels. We found that TRP canonical 7 (TRPC7) is a nociceptive mechanoreceptor and that TRPC7 channels specifically mediate the initiation of ultraviolet B (UVB)‐induced skin aging and tumor development due to p53 gene family mutations. Within 30 min after UVB irradiation, TRPC7 mediated UVB‐induced Ca²⁺ influx and the subsequent production of reactive oxygen species in skin cells. Notably, this function was unique to TRPC7 and was not observed for other TRP channels. In TRPC7 knockout mice, we did not observe the significant UVB‐associated pathology seen in wild‐type mice, including epidermal thickening, abnormal keratinocyte differentiation, and DNA damage response activation. TRPC7 knockout mice also had significantly fewer UVB‐induced cancerous tumors than did wild‐type mice, and UVB‐induced p53 gene family mutations were prevented in TRPC7 knockout mice. These results indicate that TRPC7 activity is pivotal in the initiation of UVB‐induced skin aging and tumorigenesis and that the reduction in TRPC7 activity suppresses the UVB‐induced aging process and tumor development. Our findings support that TRPC7 is a potential tumor initiator gene and that it causes cell aging and genomic instability, followed by a change in the activity of proto‐oncogenes and tumor suppressor genes to promote tumorigenesis.     

Melanogenesis‐Inhibitory and Cytotoxic Activities of Chemical Constituents from the Leaves of Sauropus androgynus L. Merr. (Euphorbiaceae)

A new steroid, 20‐hydroxyisofucosterol (stigmasta‐5,24(28)‐diene‐3β,20β‐diol) ( 7 ), along with six known compounds 1 – 6 were isolated from the MeOH extract of the leaves of Sauropus androgynus L. Merr . (Euphorbiaceae). The structure of new steroid was determined by HR‐APCI‐MS and various NMR techniques in combination with literature data. Subsequently, their anti‐inflammatory, cytotoxic activities against five human cell lines, as well as inhibitory activities against the α‐MSH induced melanogenesis on the B16 cell line were evaluated. As the results, steroid compounds, 6 and 7 exhibited moderate cytotoxic to HL60, AZ521, SKBR3, and A549 tumor cell lines (IC₅₀ 26.9 – 45.1 μm ) with high tumor selectivity for A549 relative to WI38 cell lines (SI 2.6 and 3.0, resp.). And, flavonoid compounds, 4 and 5 exhibited superior inhibitory activities against melanogenesis (67.0 – 94.7% melanin content), even with no or low toxicity to the cells (90.1 – 99.6% cell viability) at the concentrations from 10 to 100 μm . Furthermore, Western blot analysis suggested that compound 5 could inhibit melanogenesis by suppressing the protein expressions of MITF, TRP‐1, TRP‐2, and tyrosinase.     

Quantitative trait loci mapping and gene network analysis implicate protocadherin‐15 as a determinant of brain serotonin transporter expression

Presynaptic serotonin (5‐hydroxytryptamine, 5‐HT) transporters (SERT) regulate 5‐HT signaling via antidepressant‐sensitive clearance of released neurotransmitter. Polymorphisms in the human SERT gene (SLC6A4) have been linked to risk for multiple neuropsychiatric disorders, including depression, obsessive‐compulsive disorder and autism. Using BXD recombinant inbred mice, a genetic reference population that can support the discovery of novel determinants of complex traits, merging collective trait assessments with bioinformatics approaches, we examine phenotypic and molecular networks associated with SERT gene and protein expression. Correlational analyses revealed a network of genes that significantly associated with SERT mRNA levels. We quantified SERT protein expression levels and identified region‐ and gender‐specific quantitative trait loci (QTLs), one of which associated with male midbrain SERT protein expression, centered on the protocadherin‐15 gene (Pcdh15), overlapped with a QTL for midbrain 5‐HT levels. Pcdh15 was also the only QTL‐associated gene whose midbrain mRNA expression significantly associated with both SERT protein and 5‐HT traits, suggesting an unrecognized role of the cell adhesion protein in the development or function of 5‐HT neurons. To test this hypothesis, we assessed SERT protein and 5‐HT traits in the Pcdh15 functional null line (Pcdh15^av‐3J), studies that revealed a strong, negative influence of Pcdh15 on these phenotypes. Together, our findings illustrate the power of multidimensional profiling of recombinant inbred lines in the analysis of molecular networks that support synaptic signaling, and that, as in the case of Pcdh15, can reveal novel relationships that may underlie risk for mental illness .