Necessary Conditions in Social Media Addiction: Identifying Key Antecedents.

This study aims to address the fragmented understanding of the antecedents of social media addiction (SMA) by examining key factors and their roles as necessary and sufficient conditions. By integrating key variables from previous research, including the Dark Triad traits, self-regulation, social anxiety, and Fear of Missing Out (FoMO), the study investigates their relationships with SMA. Data were collected through 369 questionnaires and analyzed using regression analysis and Necessary Condition Analysis (NCA).

Iris cyst after femtosecond laser-assisted cataract surgery: a case report.

Background: Secondary iris cysts are uncommon complication after cataract surgery. The reports of an iris cyst after conventional phacoemulsification surgery are scanty, let alone the iris cyst following femtosecond laser-assisted cataract surgery (FLACS). We herein report an unusual case of an iris cyst after an uneventful FLACS.

Self-protective responses to norvaline-induced stress in a leucyl-tRNA synthetase editing-deficient yeast strain.

The editing function of aminoacyl-tRNA synthetases (aaRSs) is indispensible for formation of the correct aminoacyl-tRNAs. Editing deficiency may lead to growth inhibition and the pathogenesis of various diseases. Herein, we confirmed that norvaline (Nva) but not isoleucine or valine is the major threat to the editing function of Saccharomyces cerevisiae leucyl-tRNA synthetase (ScLeuRS), both in vitro and in vivo.

Aryl hydrocarbon receptor promotes hepatocellular carcinoma tumorigenesis by targeting intestine-specific homeobox expression.

The aryl hydrocarbon receptor (AHR), a major chemical sensor, is thought to play a role in various biological contexts, including cell cycle regulation and tumorigenesis. However, its regulatory mechanisms remain unclear. We propose herein a novel mechanism through which AHR promotes tumorigenesis by targeting expression of the oncogene intestine-specific homeobox (ISX) in hepatocellular carcinoma (HCC).

Possible association between phantom vibration syndrome and occupational burnout.

Background: Phantom vibration syndrome (PVS) and phantom ringing syndrome (PRS) occur in many cell phone users. Previous studies have indicated an association between PVS/PRS and job stress. The aim of this study was to determine if PVS/PRS were also associated with occupational burnout.

Synthesis and unexpected oxidization of the tricyclic core of ugibohlin, isophakellin, and styloguanidine.

A series of 4-substituted 5,6,7,9-tetrahydropyrrolo[2,3-f]indolizin-9-ones, representing the tricyclic core skeleton of ugibohlin, isophakellin, and styloguanidine, were synthesized via an intramolecular Vilsmeier-Haack reaction. This reaction allows the chemoselective C-C bond formation between the pyrrole C3 and proline C5 of N-[(pyrrol-2-yl)carbonyl]prolinamides to construct the B-ring without the protection of the pyrrole nitrogen. Unexpected oxidizative property of the tricyclic core skeleton was observed, which could illuminate understanding of the biological formation of these marine secondary metabolites.

Purification, cDNA cloning, and recombinant expression of chymotrypsin C from porcine pancreas.

Chymotrypsin C is a bifunctional secretory-type serine protease in pancreas; besides proteolytical activity, it also exhibits a calcium-decreasing activity in serum. In this study, we purified activated chymotrypsin C from porcine pancreas, and identified its three active forms. Active chymotrypsin C was found to be different in the length of its 13-residue activation peptide due to carboxydipeptidase (present in the pancreas) degradation or autolysis of the activated chymotrypsin C itself, resulting in the removal of several C-terminus residues from the activation peptide.

Effect of chymotrypsin C and related proteins on pancreatic cancer cell migration.

Pancreatic cancer is a malignant cancer with a high mortality rate. The amount of chymotrypsin C in pancreatic cancer cells is only 20% of that found in normal cells. Chymotrypsin C has been reported to be involved in cancer cell apoptosis, but its effect on pancreatic cancer cell migration is unclear.

Identification of neuropeptide Y-like conopeptides from the venom of Conus betulinus.

Neuropeptide Y (NPY) is a ubiquitous endocrine neuropeptide found in vertebrate and invertebrate. In our present work, two NPY-like exocrine conopeptides (designated as cono-NPYs) were first identified in the venom of cone snails. Both cono-NPYs showed sequence characteristics of invertebrate NPYs, suggesting that some exocrine venom peptides are probably evolved from the preexisting endocrine peptides during the evolution of cone snails.

Snapshot of the interaction between HIV envelope glycoprotein 120 and protein disulfide isomerase.

The human immunodeficiency virus-1 (HIV-1) envelope glycoprotein 120 (gp120) binds to cell surface receptors and mediates HIV entry. Previous studies suggest the cell surface protein disulfide isomerase (PDI) might interact with disulfide bond(s) of gp120 and thus facilitate HIV-1 entry. In the present study, a kinetic trapping approach was used to capture the disulfide cross-linking intermediate between gp120 and PDI.

Novel conopeptides in a form of disulfide-crosslinked dimer.

In our present work, seven conotoxins and conopeptides were cloned from four cone snail species based on the M-superfamily signal peptides. Among them, two conopeptides, Vt3.1 and Vt3.

Small peptides derived from the Lys active fragment of the mung bean trypsin inhibitor are fully active against trypsin.

The Bowman-Birk protease inhibitors have recently attracted attention for their potential as cancer preventive and suppressing agents. They contain two canonical binding loops, both consisting of nine highly conserved residues capable of inhibiting corresponding serine proteases. In this study, we cloned the cDNA of the mung bean trypsin inhibitor, one of the most studied Bowman-Birk protease inhibitors.

The ternary structure of the double-headed arrowhead protease inhibitor API-A complexed with two trypsins reveals a novel reactive site conformation.

The double-headed arrowhead protease inhibitors API-A and -B from the tubers of Sagittaria sagittifolia (Linn) feature two distinct reactive sites, unlike other members of their family. Although the two inhibitors have been extensively characterized, the identities of the two P1 residues in both API-A and -B remain controversial. The crystal structure of a ternary complex at 2.

New conotoxins define the novel I3-superfamily.

We purified two novel conotoxins, designated as ca11a and ca11b, from the venom of Conus caracteristicus. Based on the amino acid sequence of mature ca11a, we cloned its full-length cDNA. Based on the signal peptide of ca11a, several ca11a-like conotoxins were cloned from C.

Recombinant expression of a chitosanase and its application in chitosan oligosaccharide production.

Recently, considerable attention has been focused on chitosan oligosaccharides (COSs) due to their various biological activities. COSs can be prepared by enzymatic degradation of chitosan, which is the deacetylation product of chitin, one of the most abundant biopolymers in nature. In the current study, we recombinantly expressed a chitosanase and used it for COS preparation.

Isolation and cloning of a conotoxin with a novel cysteine pattern from Conus caracteristicus.

A new conotoxin, ca16a, containing 8 cysteine residues was purified, sequenced, and cloned from a worm-hunting snail, Conus caracteristicus. This conotoxin is an extremely hydrophilic peptide comprising 34 residues, with 4 acidic and 4 basic residues. It is rich in polar Gly, Ser, and Thr residues and includes a hydroxylated Pro residue.

Two different groups of signal sequence in M-superfamily conotoxins.

M-superfamily conotoxins can be divided into four branches (M-1, M-2, M-3 and M-4) according to the number of amino acid residues in the third Cys loop. In general, it is widely accepted that the conotoxin signal peptides of each superfamily are strictly conserved. Recently, we cloned six cDNAs of novel M-superfamily conotoxins from Conus leopardus, Conus marmoreus and Conus quercinus, belonging to either M-1 or M-3 branch.

Cloning and isolation of a Conus cysteine-rich protein homologous to Tex31 but without proteolytic activity.

We cloned and isolated a cysteine-rich protein, designated Mr30, from Conus marmoreus. Mr30 belongs to the cysteine-rich secretory protein family that is highly homologous to Tex31 previously obtained from Conus textile and reported as a protease responsible for processing of pro-conotoxins. Mr30, purified by a procedure similar to that of Tex31, indeed showed low proteolytic activity.

Biological characteristics of dengue virus and potential targets for drug design.

Dengue infection is a major cause of morbidity in tropical and subtropical regions, bringing nearly 40% of the world population at risk and causing more than 20,000 deaths per year. But there is neither a vaccine for dengue disease nor antiviral drugs to treat the infection. In recent years, dengue infection has been particularly prevalent in India, Southeast Asia, Brazil, and Guangdong Province, China.

Molecular cloning, expression and characterization of protein disulfide isomerase from Conus marmoreus.

The oxidative folding of disulfide-rich conotoxins is essential for their biological functions. In vivo, disulfide bond formation is mainly catalyzed by protein disulfide isomerase. To elucidate the physiologic roles of protein disulfide isomerase in the folding of conotoxins, we have cloned a novel full-length protein disulfide isomerase from Conus marmoreus.

Solution structure of an M-1 conotoxin with a novel disulfide linkage.

The M-superfamily of conotoxins has a typical Cys framework (-CC-C-C-CC-), and is one of the eight major superfamilies found in the venom of the cone snail. Depending on the number of residues located in the last Cys loop (between Cys4 and Cys5), the M-superfamily family can be divided into four branches, namely M-1, -2, -3 and -4. Recently, two M-1 branch conotoxins (mr3e and tx3a) have been reported to possess a new disulfide bond arrangement between Cys1 and Cys5, Cys2 and Cys4, and Cys3 and Cys6, which is different from those seen in the M-2 and M-4 branches.

From the identification of gene organization of alpha conotoxins to the cloning of novel toxins.

In the venoms of cone snails, alpha conotoxins are competitive antagonists of nicotinic acetylcholine receptors. Eleven novel cDNA and eight partial gene sequences (including two pseudogenes) of alpha conotoxins were identified from five species of cone snail. As expected, every cDNA encodes a precursor of prepropeptide.

Characterization of novel M-superfamily conotoxins with new disulfide linkage.

The M-superfamily with the typical Cys framework (-CC-C-C-CC-) is one of the seven major superfamilies of conotoxins found in the venom of cone snails. Based on the number of residues in the last Cys loop (between C4 and C5), M-superfamily conotoxins can be provisionally categorized into four branches (M-1, M-2, M-3, M-4) [Corpuz GP, Jacobsen RB, Jimenez EC, Watkins M, Walker C, Colledge C, Garrett JE, McDougal O, Li W, Gray WR, et al. (2005) Biochemistry44, 8176-8186].

Template-assisted rational design of peptide inhibitors of furin using the lysine fragment of the mung bean trypsin inhibitor.

Highly active, small-molecule furin inhibitors are attractive drug candidates to fend off bacterial exotoxins and viral infection. Based on the 22-residue, active Lys fragment of the mung bean trypsin inhibitor, a series of furin inhibitors were designed and synthesized, and their inhibitory activity towards furin and kexin was evaluated using enzyme kinetic analysis. The most potent inhibitor, containing 16 amino acid residues with a Ki value of 2.

Early-onset behavioral and synaptic deficits in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder for which numerous mouse models have been generated. In both AD patients and mouse models, there is increasing evidence that neuronal dysfunction occurs before the accumulation of beta-amyloid (Abeta)-containing plaques and neurodegeneration. Characterization of the timing and nature of preplaque dysfunction is important for understanding the progression of this disease and to identify pathways and molecular targets for therapeutic intervention.