Ripening of avocado fruits studied by spectroscopic techniques

Avocados are considered very healthy due to the high content mono‐unsaturated lipid, essential vitamins and minerals, minimal sugar and no cholesterol and are therefore sometimes referred to as “the perfect fruits”. Avocados, mainly grown in Latin‐America, are harvested unripe and sent overseas. However, the ripening process is very difficult to assess visually and tactilely. A tool for precise noninvasive judgment of the status would be valuable as the fruit is too expensive to be cut open unripe or overdue. A white‐light source and a light‐emitting diode unit with four excitation wavelengths (365, 385, 395, and 405 nm) were used for reflectance and fluorescence spectroscopy in a fiber‐coupled set‐up for noninvasive monitoring. Twelve non‐ripe avocados, with approximately the same size and appearance, were studied and divided into three groups and kept at three different storage conditions; at room temperature, in a refrigerator and a combination of the two. We showed that fluorescence was useful for following the ripening process. A method, which compensates for the spatial variations in spectral properties around a fruit, is described. Remote fluorescence monitoring, intended for orchard use, was also demonstrated. A low‐cost device based on fluorescence for avocado ripeness assessment is proposed.     

The adenosine transporter,ENT1, in cardiomyocytes is sensitive to inhibition by ethanol in a kinase-dependent manner: implications for ethanol-dependent cardioprotection and nucleoside analog drug cytotoxicity

The adenosine transporter 1 (ENT1) transports nucleosides, such as adenosine, and cytotoxic nucleoside analog drugs. ENT1 is well established to play a role in adenosinergic signaling in the cardiovascular system by modulating adenosine levels. Moderate ethanol consumption is cardioprotective and underlying mechanisms of action are not clear although adenosinergic signaling has been implicated. Here, we show that ethanol (5–200 mM) significantly reduces ENT1-dependent [³H] 2-chloroadenosine uptake (by up to 27 %) in the cardiomyocyte cell line, HL-1. Inhibition or absence of ENT1 is known to be cardioprotective, suggesting that the interaction of ethanol with ENT1 may promote adenosinergic cardioprotective pathways in the cardiovasculature. Ethanol sensitivity of adenosine uptake is altered by pharmacological activation of PKA and PKC. Primary cardiomyocytes from PKCε-null mice have significantly greater sensitivity to inhibition (by approximately 37 %) of adenosine uptake by ethanol than controls. These data suggest that the presence of ethanol may compromise ENT1-dependent nucleoside analog drug cytotoxicity, and indeed, ethanol (5 mM) reduces the cytotoxic effects of gemcitabine (2 nM), an anti-cancer drug, in the human cancer cell line, HTB2. Thus, the pharmacological inhibition of ENT1 by ethanol may contribute to ethanol-dependent cardioprotection but compromise gemcitabine cytotoxicity.     

Role of Inn1 and its interactions with Hof1 and Cyk3 in promoting cleavage furrow and septum formation in S. cerevisiae

Cytokinesis requires coordination of actomyosin ring (AMR) contraction with rearrangements of the plasma membrane and extracellular matrix. In Saccharomyces cerevisiae, new membrane, the chitin synthase Chs2 (which forms the primary septum [PS]), and the protein Inn1 are all delivered to the division site upon mitotic exit even when the AMR is absent. Inn1 is essential for PS formation but not for Chs2 localization. The Inn1 C-terminal region is necessary for localization, and distinct PXXP motifs in this region mediate functionally important interactions with SH3 domains in the cytokinesis proteins Hof1 (an F-BAR protein) and Cyk3 (whose overexpression can restore PS formation in inn1Δ cells). The Inn1 N terminus resembles C2 domains but does not appear to bind phospholipids; nonetheless, when overexpressed or fused to Hof1, it can provide Inn1 function even in the absence of the AMR. Thus, Inn1 and Cyk3 appear to cooperate in activating Chs2 for PS formation, which allows coordination of AMR contraction with ingression of the cleavage furrow.     

Mercury deposits in neurons of the trigeminal ganglia after insertion of dental amalgam in rats

An amalgam filling was inserted into the first upper molar of 12 rats and the animals were killed after 3–9 months. Tissue sections from the trigeminal ganglia and the brain stem were then investigated with a sensitive histochemical technique to trace mercury deposits. Within the trigeminal ganglia, nerve cells with mercury deposits were observed in seven out of 12 rats, whereas no mercury was detected in sections from the brain stem. The mechanism responsible for the accumulation of mercury in neurons of the trigeminal ganglia is discussed.     

Cell-Penetrating Mimics of Agonist-Activated G-Protein Coupled Receptors

Cell-penetrating peptides have proven themselves as valuable vectors for intracellular delivery. Relatively little is known about the frequency of cell-penetrating sequences in native proteins and their functional role. By computational comparison of peptide sequences, we recently predicted that intracellular loops of G-protein coupled receptors (GPCR) have high probability for occurrence of cell-penetrating motifs. Since the loops are also receptor and G-protein interaction sites, we postulated that the short cell-penetrating peptides, derived from GPCR, when applied extracellularly can pass the membrane and modulate G-protein activity similarly to parent receptor proteins. Two model systems were analyzed as proofs of the principle. A peptide based on the C-terminal intracellular sequence of the rat angiotensin receptor (AT1AR) is shown to internalize into live cells and elicit blood vessel contraction even in the presence of AT1AR antagonist Sar¹-Thr⁸-angiotensin II. The peptide interacts with the same selectivity towards G-protein subtypes as agonist-activated AT1AR and blockade of phospholipase C abolishes its effect. Another cell-penetrating peptide, G53-2 derived from human glucagon-like peptide receptor (GLP-1R) is shown to induce insulin release from isolated pancreatic islets. The mechanism was again found to be shared with the original GLP-1R, namely G₁₁-mediated inositol 1,4,5-triphosphate release pathway. These data reveal a novel possibility to mimic the effects of signalling transmembrane proteins by application of shorter peptide fragments.     

Deconstructing Protein in the Diet and Biomass of Colobine Primates

International Journal of Primatology - Dietary protein is often considered a factor that limits the growth of primate populations. The ratio of crude protein (CP) to fiber in common mature leaves...     

Transcriptional control by two leucine-responsive regulatory proteins in <Emphasis Type="Italic">Halobacterium salinarum</Emphasis> R1

Background  

Archaea combine bacterial-as well as eukaryotic-like features to regulate cellular processes. Halobacterium salinarum R1 encodes eight leucine-responsive regulatory protein (Lrp)-homologues. The function of two of them, Irp (OE3923F) and lrpA1 (OE2621R), were analyzed by gene deletion and overexpression, including genome scale impacts using microarrays.     

Values of MMP-2 and MMP-9 in Tumor Tissue of Basal-Like Breast Cancer Patients

Gelatinase A (MMP-2) and gelatinase B (MMP-9) are proteolytic enzymes involved in process of tumor invasion, and they are considered as possible tumor markers in breast cancer patients. In this study, we measured activity of latent and active form of MMP-2 and MMP-9 in tumor and adjacent tissue of 60 breast cancer patients by SDS-PAGE zymography. The activity of both form of gelatinases significantly increased with each advancing clinical stage of disease. ProMMP-9 and aMMP-9 activity in tumor tissue shows a positive association with tumor size. Patients with lymph node involvement have higher proMMP-2, aMMP-2 and aMMP-9 activity than node negative patients. Steroid receptor-negative tumors had enhanced aMMP-2 and aMMP-9 activity. Patients with basal-like cancers had higher proMMP-2 tumor activity and aMMP-2 adjacent tissue activity compared to patients with luminal A tumors. Patients with negative hormone receptors are associated with increased activity of both form of gelatinases in adjacent tissue. Reported increased activity of MMP-2 in tumor and adjacent tissue of basal-like tumors implicates that MMP-2 might have a role in aggressive biology of basal-like cancers. Additional investigations regarding molecular pathways in adjacent tissue could give better insight into aggressive nature of basal-like carcinomas.