Quantitative Succinyl-Proteome Profiling of Camellia sinensis cv. 'Anji Baicha' During Periodic Albinism.

Lysine succinylation is a novel dynamic and evolutionarily conserved post-translational modification (PTM) that regulates various biological processes. 'Anji Baicha' is an albino tea variety that exhibits temperature-based variability of leaf colour and amino acid concentrations. However, the mechanism underlying albinism in 'Anji Baicha' has not been investigated at the level of succinylation. Here, we identify 3530 lysine succinylation sites mapped to 2132 proteins in 'Anji Baicha', representing the first extensive data on the lysine succinylome in the tea plant. Eleven conserved succinylation motifs were enriched among the identified succinylated peptides. The protein-protein interaction maps were visualized using Cytoscape software. Comparison across three typical developmental stages of 'Anji Baicha' revealed that proteins exhibiting differential succinylation levels were primarily involved in photosynthesis, carbon fixation, biosynthesis of amino acids and porphyrin and chlorophyll metabolism, suggesting that these succinylated proteins are involved in 'Anji Baicha' leaf colour variability. These results not only deepen our understanding of the mechanism underlying 'Anji Baicha' albinism and the regulatory role of succinylation in the tea plant but also provide new insight into molecular breeding for leaf colour variety.

Duration sensitivity of neurons in the primary auditory cortex of albino mouse.

Many neurons in the central auditory system of a number of species have been found to be sensitive to the duration of sound stimuli. While previous studies have shown that γ-aminobutyric acid (GABA)-ergic inhibitory input is important for duration sensitivity in the inferior colliculus (IC), it is still unknown whether (GABA)-ergic inhibitory input plays an important role in generating duration sensitivity in the cortex. Using free-field sound stimulation and in vivo extracellular recording, we investigated duration sensitivity in primary auditory cortical (AI) neurons of the Nembutal anesthetized albino mouse (Mus musculus, Km) and examined the effect of the GABAA receptor antagonist bicuculline on AI neuron duration sensitivity. A total of 63 duration tuning curves were measured in AI neurons. Of these, 44% (28/63) exhibited duration sensitive responses, while 43% (27/63) lacked duration sensitivity. The remaining 13% (8/63) exhibited long-pass properties likely reflecting both duration sensitive and insensitive features. We found that duration sensitive neurons had shorter first spike latency (FSL) and longer firing duration (FD) when stimulated with best duration (p < 0.05), while duration insensitive neurons had invariable FSL and FD at different sound durations (p>0.05). Furthermore, 60% (6/10) of duration sensitive neurons and 75% (3/4) long-pass neurons lost duration sensitivity following bicuculline application. Taken together, our results show that cortical neurons in the albino mouse are sensitive to sound duration, and that GABAergic inhibition may play an important role in the formation of de novo duration sensitivity in AI. The possible mechanism and behavioral significance of duration sensitivity in AI neurons is discussed.

Synergistic effect of conjugated linolenic acid isomers against induced oxidative stress, inflammation and erythrocyte membrane disintegrity in rat model.

BACKGROUND: α-Eleostearic acid and punicic acid, two typical conjugated linolenic acid (CLnA) isomers present in bitter gourd and snake gourd oil respectively, exhibit contrasting cis-trans configuration which made them biologically important. METHODS: Rats were divided into six groups. Group 1 was control and group 2 was treated control. Rats in the groups 3 and 4 were treated with mixture of α-eleostearic acid and punicic acid (1:1) (0.5% and 1.0% respectively) while rats in the groups 5 and 6 were treated with 0.5% of α-eleostearic acid and 0.5% of punicic acid respectively along with sodium arsenite by oral gavage once per day. RESULTS: Results showed that increase in nitric oxide synthase (NOS) activity, inflammatory markers expression, platelet aggregation, lipid peroxidation, protein oxidation, DNA damage and altered expression of liver X receptor-α (LXR-α) after arsenite treatment were restored with the supplementation of oils containing CLnA isomers. Altered activities of different antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and ferric reducing ability of plasma (FRAP) also restored after oil supplementation. Altered morphology and fluidity of erythrocyte membrane studied by atomic force and scanning electron microscopy, after stress induction were significantly improved due to amelioration in cholesterol/phospholipid ratio and fatty acid profile of membrane. Oils treatment also improved morphology of liver and fatty acid composition of hepatic lipid. CONCLUSIONS: Overall two isomers showed synergistic antioxidant and anti-inflammatory effect against induced perturbations and membrane disintegrity. GENERAL SIGNIFICANCE: Synergistic antioxidant and anti-inflammatory role of these CLnA isomers were established by this study.

Dispersion of peptides in vegetable oil as a simple slow release formula for both injection and oral uptake in insects: a case study with [His7]-corazonin in an albino Locusta migratoria deficient in corazonin.

Upon realizing that for drug delivery in the body, lipidization is a technique used in the pharmaceutical industry, we took in consideration that corazonin melanizes the cuticle of albino Locusta migratoria only when injected in an emulsion in oil, not when applied in a watery solution. In this study, we investigate the possibility for oral uptake of corazonin dispersed in oil, and validated the activity by a melanization assay. Not only was it active, it also induced red cuticular coloration in some animals, and it was also unexpectedly lethal for nymphs, but not for adults. These results necessitate the revision of the potential of (some) peptides for insect control. Also, they suggest practical recommendations for the application of other peptides in physiological assays where oil could be used as a simple slow release formula.

L-DOPA is an endogenous ligand for OA1.

Albinism is a genetic defect characterized by a loss of pigmentation. The neurosensory retina, which is not pigmented, exhibits pathologic changes secondary to the loss of pigmentation in the retina pigment epithelium (RPE). How the loss of pigmentation in the RPE causes developmental defects in the adjacent neurosensory retina has not been determined, but offers a unique opportunity to investigate the interactions between these two important tissues. One of the genes that causes albinism encodes for an orphan GPCR (OA1) expressed only in pigmented cells, including the RPE. We investigated the function and signaling of OA1 in RPE and transfected cell lines. Our results indicate that OA1 is a selective L-DOPA receptor, with no measurable second messenger activity from two closely related compounds, tyrosine and dopamine. Radiolabeled ligand binding confirmed that OA1 exhibited a single, saturable binding site for L-DOPA. Dopamine competed with L-DOPA for the single OA1 binding site, suggesting it could function as an OA1 antagonist. OA1 response to L-DOPA was defined by several common measures of G-protein coupled receptor (GPCR) activation, including influx of intracellular calcium and recruitment of beta-arrestin. Further, inhibition of tyrosinase, the enzyme that makes L-DOPA, resulted in decreased PEDF secretion by RPE. Further, stimulation of OA1 in RPE with L-DOPA resulted in increased PEDF secretion. Taken together, our results illustrate an autocrine loop between OA1 and tyrosinase linked through L-DOPA, and this loop includes the secretion of at least one very potent retinal neurotrophic factor. OA1 is a selective L-DOPA receptor whose downstream effects govern spatial patterning of the developing retina. Our results suggest that the retinal consequences of albinism caused by changes in melanin synthetic machinery may be treated by L-DOPA supplementation.

Some indolic compounds as markers of the melanocyte activity.

The melanocyte activity was studied by analysis of the urinary excretion of indolic and cysteinyldopa compounds. One eumelanin marker, 5,6-dihydroxy-indole-2-carboxylic acid was identified and quantified in normal urine. However, its low concentration and sensitivity to oxidation made it less suitable for clinical studies. A methylated derivative of this substance, 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI-2-C), was also demonstrated in normal urine. A quantitative method was worked out and the normal urinary concentration of this substance was as high as the concentration of 5-S-cysteinyldopa. The concentrations of the eumelanic marker 6-hydroxy-5-methoxyindole-2-carboxylic acid and the pheomelanic marker 5-S-cysteinyldopa were determined in the urine of psoriasis patients during PUVA treatment and also in the urine of subjects with different skin colour. The melanocyte activity in albinotic patients and in albinotic mice was studied by the same technique. Some in vitro experiments were performed to show that 5-S-glutathionyldopa has the molecular properties of forming a mercapto-substituted indole derivative. The following main conclusions were drawn: 1. 5,6-Dihydroxyindole-2-carboxylic acid and 6-hydroxy-5-methoxyindole-2-carboxylic acid are both present in measurable amounts in normal urine. 2. The urinary concentration of 6-hydroxy-5-methoxyindole-2-carboxylic acid increased during PUVA treatment in a similar way as for 5-S-cysteinyldopa. 3. The eumelanic marker 6-hydroxy-5-methoxyindole-2-carboxylic acid was excreted in larger quantities by people with genetically dark skin, whereas the pheomelanic marker 5-S-cysteinyldopa was not related to pigment type. 4. In the urine of one albino patient and in the urine of albinotic mice a total absence of 6-hydroxy-5-methoxyindole-2-carboxylic acid was found. The urinary concentrations of 5-S-cysteinyldopa in these subjects were measurable but lower than in pigmented subjects. Thus, 6-hydroxy-5-methoxy-indole-2-carboxylic acid seems to be a more specific melanocyte marker than the cysteinyldopas.(ABSTRACT TRUNCATED AT 400 WORDS)