Eye lens β-crystallins are predicted by native ion mobility-mass spectrometry and computations to form compact higher-ordered heterooligomers

Eye lens crystallin proteins maintain the refractive properties of the lens but are not replaced after denucleation. Rolland et al. use native ion mobility-mass spectrometry, kinetics experiments, and computations to reveal that b-crystallins form heterodimers. These likely assemble into compact heterooligomers that enable the very high protein concentrations found in lens tissue

Oligopeptide Transporter-1 is Associated with Fluorescence Intensity of 5-Aminolevulinic Acid-Based Photodynamic Diagnosis in Pancreatic Cancer Cells

[Background] The 5-aminolevulinic acid (ALA)-based photodynamic diagnosis is based on the accumulation of photosensitizing protoporphyrin IX in the tumor after ALA administration. However, the mechanisms connecting exogenous ALA and tumor fluorescence in pancreatic cancer remain unclear. We aimed to elucidate the mechanism underlying the ALA-induced fluorescent. [Methods] Human pancreatic duct epithelial cells (hPDECs) and pancreatic cancer cell lines were used. The expressions of ALA-associated enzymes and membrane transporters in these cell lines were investigated. ALA-induced fluorescence was also investigated. [Results] The expression of oligopeptide transporter-1 (PEPT-1), through which ALA is absorbed, was significantly higher in AsPC-1 cells and lower in MIA PaCa-2 cells than in hPDECs. AsPC-1 cells showed rapid and intense fluorescence after ALA administration, and that was attenuated by PEPT-1 inhibition. ALA-induced fluorescence was not sufficiently strong in MIA PaCa-2 cells to distinguish the cells from hPDECs. [Conclusion] We revealed the association of PEPT-1 with ALA-induced fluorescence. Cancers expressing PEPT-1 could be easily distinguished by this technique from normal cells. These findings help develop novel diagnostic modalities for pancreatic cancer

Elucidation of the mechanism of subunit exchange in αB crystallin oligomers

AlphaB crystallin (αB-crystallin) is a key protein for maintaining the long-term transparency of the eye lens. In the eye lens, αB-crystallin is a “dynamical” oligomer regulated by subunit exchange between the oligomers. To elucidate the unsettled mechanism of subunit exchange in αB-crystallin oligomers, the study was carried out at two different protein concentrations, 28.5 mg/mL (dense sample) and 0.45 mg/mL (dilute sample), through inverse contrast matching small-angle neutron scattering. Interestingly, the exchange rate of the dense sample was the same as that of the dilute sample. From analytical ultracentrifuge measurements, the coexistence of small molecular weight components and oligomers was detected, regardless of the protein concentration. The model proposed that subunit exchange could proceed through the assistance of monomers and other small oligomers; the key mechanism is attaching/detaching monomers and other small oligomers to/from oligomers. Moreover, this model successfully reproduced the experimental results for both dense and dilute solutions. It is concluded that the monomer and other small oligomers attaching/detaching mainly regulates the subunit exchange in αB-crystallin oligomer

Immunological detection of D-β-aspartate-containing protein in lens-derived cell lines

Alpha-crystallin is the major protein of the mammalian lens and its average molecular weight is approximately 800 kDa. It is composed of two kinds of structurally and functionally related polypeptides, αA-and αB-crystallin subunits, each with a molecular weight of 20 kDa Recently, we prepared a polyclonal antibody against peptide Gly-Leu-D-β-Asp-Ala-Thr-Gly-Leu-D-β-Asp-Ala-ThrGly-Leu-D-β-Asp-Ala-Thr (anti-peptide 3R antibody) that corresponded to three repeats of positions 149-153 in human αA-crystallin [11]. This antibody cross-reacted specifically with D-β-Asp-151-containing αA-crystallin. Because formation of D-Asp is accompanied by isomerization to form the β-Asp (isoaspartate) residue, three isomers of Asp residues, L-β-Asp, D-α-Asp and D-β-Asp isomers, are formed in the protein Cell culture systems are used widely for the analysis of cellular functions related to particular organ systems. For lens research, it is of particular interest to find conditions that reflect the situation within this organ. In order to establish whether the D-β-Asp-containing protein is present in cultured lens cells, we cultured two cell lines, αTN4-1 and N/N1003A, which are commonly used in lens research Conclusions: The results indicate that the N/N1003A cell line expressed a 50 kDa D-β-Asp-containing protein, which may share a common amino acid sequence with αA-and αB-crystallin

Analysis of the 619 Brånemark System TiUnite Implants : A Retrospective Study

The purpose of this retrospective study was to determine the outcome of Brånemark System TiUnite® implants (Nobel Biocare/Sweden), and to identify the risk factors associated with implant failure. A total of 151 patients (83 maxillae and 91 mandibles) received 619 implants from July 2003 until May 2010. The patients included 86 males and 65 females, with a median age of 51.6 years and an age range of 16 to 90 years at the time of implant surgery. Seventeen maxillae and 16 mandibles were completely edentulous, and 66 maxillae and 75 mandibles were partially edentulous. All the patients were followed until June 2011. Among the 619 implants, 9 maxillary implants and 8 mandibular implants were unsuccessful. The overall survival rate was 96.82%. A logistic regression analysis identified that a history of steroid treatment, application of a dento-maxillary prosthesis, a lack of mechanical coupling between the implants, and the length of the implants (≤8.5mm) were significant predictors of implant failure

The royal food of termites shows king and queen specificity

シロアリの王と女王の特別食を世界初解明 --王と女王の繁殖と長寿を支えるロイヤルフード--. 京都大学プレスリリース. 2023-07-13.Society in eusocial insects is based on the reproductive division of labor, with a small number of reproductive individuals supported by a large number of non-reproductive individuals. Because inclusive fitness of all colony members depends on the survival and fertility of reproductive members, sterile members provide royals with special treatment. Here we show that termite kings and queens each receive special food of a different composition from workers. Sequential analysis of feeding processes demonstrated that workers exhibit discriminative trophallaxis, indicating their decision-making capacity in allocating food to the kings and queens. LC-MS/MS analyses of the stomodeal food and midgut contents revealed king- and queen-specific compounds including diacylglycerols and short-chain peptides. DESI-MSI analyses of ¹³C-labelled termites identified phosphatidylinositol and acetyl-L-carnitine in the royal food. Comparison of the digestive tract structure showed remarkable differences in the volume ratio of the midgut-to-hindgut among castes, indicating that digestive division of labor underlies reproductive division of labor. Our demonstration of king- and queen-specific food in termites provides insight into the nutritional system that underpins the extraordinary reproduction and longevity of royals in eusocial insects

Total and High Molecular Weight Adiponectin and Hepatocellular Carcinoma with HCV Infection

Adiponectin is shown to be inversely associated with development and progression of various cancers. We evaluated whether adiponectin level was associated with the prevalence and histological grade of hepatocellular carcinoma (HCC), and liver fibrosis in patients with hepatitis C virus (HCV) infection.A case-control study was conducted on 97 HCC patients (cases) and 97 patients (controls) matched for sex, Child-Pugh grade and platelet count in patients with HCV infection. The serum total and high molecular weight (HMW) adiponectin levels were measured by enzyme-linked immunosorbent assays and examined in their association with the prevalence of HCC. In addition, the relationship between these adiponectin levels and body mass index (BMI), progression of liver fibrosis, and histological grade of HCC was also evaluated. Liver fibrosis was assessed using the aspartate aminotransferase to platelet ratio index (APRI).There were no significant differences in the serum total and HMW adiponectin levels between cases and controls. Moreover, there were no inverse associations between serum total and HMW adiponectin levels and BMI in both cases and controls. On the other hand, serum total and HMW adiponectin levels are positively correlated with APRI in both cases (r = 0.491, P<0.001 and r = 0.485, P<0.001, respectively) and controls (r = 0.482, P<0.001 and r = 0.476, P<0.001, respectively). Interestingly, lower serum total (OR 11.76, 95% CI: 2.97–46.66 [P<0.001]) and HMW (OR 10.24, CI: 2.80–37.40 [P<0.001] adiponectin levels were independent risk factors of worse histological grade of HCC.Our results suggested that serum total and HMW adiponectin levels were predictors of liver fibrosis, but not prevalence of HCC in patients with HCV infection. Moreover, low these adiponectin levels were significantly associated with worse histological grades

質量分析装置を用いるタンパク質中D型アミノ酸残基の同定

加齢後の組織中タンパク質内部の様々な部位に存在すると考えられる異性化Aspを同定するためには，キラル誘導体分離法，ジアステレオマー誘導体化法など煩雑な研究手法の組み合わせが一般的であった．これに対して，著者らの研究室では質量分析装置を『質量検知装置』として用い，液体クロマトグラフィーと組み合わせた手法を開発，改良して簡便・迅速にタンパク質中の異性化Asp部位を決定することに成功した．本手法では，2段階の酵素消化に応じて生成する合計4つの試料を同条件のnano-scale液体クロマトグラフィー連結型の質量分析装置へと導入する．各ペプチド断片中でAsp異性体に準じた酵素の作用による分子量変化が生じるため，質量で描くクロマトグラムから各々対応するペプチド断片のピークが消失する．これを利用することで各Asp異性化部位の同定及びAsp異性体の区別を同時に行うことが可能となった.Homochirality of amino acid residues of protein is essential for life. For a long time, it was believed that D-amino acids were excluded from living systems, and that proteins consisted only of L-amino acids. However, recent developments in analytical techniques have led to the discovery of D-amino acids in living organisms, such as peptides and proteins. Many D-amino acids are aspartates, which are located in various sites within metabolically inactive tissues. In order to identify such aspartate residues in protein, a combination of complicated methods and instruments has been previously applied. In contrast, our laboratory has recently developed a rapid, easy and comprehensive method to identify D-Asp and β-Asp in tissues using LC-MS/MS, thus using mass spectrometry as a “mass detection device”. A total of four samples from the same tissue and proteins, generated in two steps of enzymatic digestion, are used for LC-MS/MS. The identification of each iso-Asp containing peptide peak is performed by the disappearance of the chromatogram due to the alteration of molecular weight by each enzymatic digestion. By using this methodology, it is possible to identify and distinguish each D-Asp and β-Asp in protein without a set of complicated methods and instruments