inhibitor, 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). The affinity of [14C]L-leucine uptake and the inhibition profiles of [14C]L-leucine uptake by various amino acids in the Saos2 cells were comparable with those for the LAT1 expressed in Xenopus oocytes. The majority of [14C]Lleucine uptake is, therefore, mediated by LAT1 in the Saos2 cells. These results suggest that the transports of neutral amino acids including several essential amino acids into Saos2 human osteogenic sarcoma cells are for the most part mediated by LAT1. Therefore, the Saos2 human osteogenic sarcoma cells are excellent tools for examine the properties of LAT1. Moreover, the specific inhibition of LAT1 in tumor cells might be a new rationale for anti-tumor therapy.
Amino Acid Transport System L* ; Amino Acids ; Amino Acids, Essential ; Amino Acids, Neutral ; Humans* ; Oocytes ; Osteosarcoma* ; Xenopus

BACKGROUND/AIMS: Amino acids have many physiological activities. We report the correlation between gastric emptying and gastric adaptive relaxation using tryptophan and amino acids with a straight alkyl chain, hydroxylated chain, and branched chain. Here we sought to further clarify the correlation between gastric emptying and gastric adaptive relaxation by using other amino acids. METHODS: In Sprague-Dawley rats, gastric emptying was evaluated by a breath test using [1-¹³C] acetic acid. The expired ¹³CO₂ pattern, T(max), C(max), and AUC(120min) values were used as evaluation items. Gastric adaptive relaxation was evaluated in a barostat experiment. Individual amino acids (1 g/kg) were administered orally 30 minutes before each breath test or barostat test. RESULTS: L-phenylalanine and L-tyrosine did not influence gastric emptying. All other amino acids, ie, L-proline, L-histidine, L-cysteine, L-methionine, L-aspartic acid, L-glutamic acid, L-asparagine, L-arginine, L-glutamine, and L-lysine significantly delayed and inhibited gastric emptying. L-Cysteine and L-aspartic acid significantly enhanced and L-methionine and L-glutamine significantly inhibited gastric adaptive relaxation. L-Phenylalanine moved the balloon toward the antrum, suggesting strong contraction of the fundus. T(max) showed a significant positive correlation (r = 0.709), and C(max) and AUC(120min) each showed negative correlations (r = 0.613 and 0.667, respectively) with gastric adaptive relaxation. CONCLUSION: From the above findings, it was found that a close correlation exists between gastric emptying and adaptive relaxation, suggesting that enhanced gastric adaptive relaxation inhibits gastric emptying.
Acetic Acid ; Amino Acids* ; Animals ; Arginine ; Asparagine ; Aspartic Acid ; Breath Tests ; Cysteine ; Gastric Emptying* ; Glutamic Acid ; Glutamine ; Histidine ; Lysine ; Methionine ; Phenylalanine ; Proline ; Rats ; Rats, Sprague-Dawley ; Relaxation* ; Tryptophan ; Tyrosine

The continuous growth and proliferation of cells are essential for the wound healing process, and the amino acid transporters plays an important role in the continuous growing and proliferating cells. Among the amino acid transport systems, the amino acid transport system L, which is a Na+/-independent neutral amino acid transport system, is a major route for providing living cells including tumor cells with neutral amino acids including several essential amino acids. In the present study, to elucidate the role of amino acid transport system L in the wound healing process, we investigated the expression pattern of LAT1 and LAT2 in the healing process after inflicting the wound on skin of rat. The expression of LAT1 was increased at 12 hours after inflicting the wound and was similar to the control group getting closer to 7 days. The expression of LAT2 was increased at 1 day and 3 days after inflicting the wound and was similar to the control group getting closer to 7 days. These results suggest that the LAT1 and LAT2 play important roles at the early stage and at the middle stage getting closer to normal skin in the wound healing process after inflicting the wound, respectively.
Amino Acid Transport System L ; Amino Acid Transport Systems* ; Amino Acids, Essential ; Amino Acids, Neutral ; Animals ; Rats* ; Skin* ; Wound Healing* ; Wounds and Injuries*

Methylation plays a vital role in biological systems. SAM (S-adenosyl-L-methionine), an abundant cofactor in life, acts as a methyl donor in most biological methylation reactions. SAM-dependent methyltransferases (MTase) transfer a methyl group from SAM to substrates, thereby altering their physicochemical properties or biological activities. In recent years, many SAM analogues with alternative methyl substituents have been synthesized and applied to methyltransferases that specifically transfer different groups to the substrates. These include functional groups for labeling experiments and novel alkyl modifications. This review summarizes the recent progress in the synthesis and application of SAM methyl analogues and prospects for future research directions in this field.
S-Adenosylmethionine/metabolism* ; Methionine ; Methyltransferases/metabolism* ; Methylation ; Racemethionine

The characteristics of Na+/-dependent cycloleucine uptake was investigated in OK cells with regard to substrate specificity and regulation by protein kinase C (PKC). Inhibition studies with different synthetic and natural amino acids showed a broad spectrum affinity to neutral amino acids regardless of their different side chains including branched or aromatic, indicating that the Na+/-dependent cycloleucine uptake in OK cells is mediated by System B-o or System B degree -like transporter rather than the classical System A or ASC. Phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-dibutyrate, but not 4 alpha-PMA elicited a time-dependent biphasic stimulation of Na+/-dependent cycloleucine uptake, which produced early transient peak at 30 min and late sustained peak at 180 min. Both the early and late stimulations by PMA were due to an increase in Vmax and not due to a change in Km. PKC inhibitors blocked both the early and late stimulation by PMA, while protein synthesis inhibitors blocked the late stimulation only. These results suggest the existence and regulation by PKC of System B degree or System B degree -like broad spectrum transport system for neutral amino acids in OK cells.
Amino Acid Transport Systems* ; Amino Acids ; Amino Acids, Neutral ; Cycloleucine ; Kidney* ; Opossums* ; Phorbol 12,13-Dibutyrate ; Protein Kinase C ; Protein Synthesis Inhibitors ; Substrate Specificity

The periodontium is a topographically complex organ consisting of epithelial tissue, soft and mineralized tissues. Structures comprising the periodontium include the gingiva, periodontal ligament (PDL), cementum and the alveolar bone. The molecular mechanism of differentiation in PDL fibroblast cells remain unclear. Amino acid transporters play an important role in supplying nutrition to normal and cancer cells and for cell proliferation. Amino acid transport system L is a major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The system L is divided into two major subgroups, the L-type amino acid transporter 1 (LAT1) and the L-type amino acid transporter 2 (LAT2). In this study, the expression pattern of amino acid transport system L was, therefore, investigated in the differentiation of PDL fibroblast cells. To determine the expression level of amino acid transport system L participating in intracellular transport of amino acids in the differentiation of PDL fibroblast cells, it was examined by RT-PCR, observation of cell morphology, Alizaline red-S staining and uptake analysis after inducing experimental differentiation in PDL fibroblast cells isolated from mouse molar teeth. The results are as follows. 1. The LAT1 mRNA was expressed in the early stage of PDL fibroblast cell differentiation. This expression level was gradually reduced by differentiation-inducing time and it was not observed after the late stage. 2. The expression level of LAT2 mRNA was increased in time-dependent manner during differentiation induction of PDL fibroblast cells. 3. There was no changes in the expression level of 4F2hc mRNA, the cofactor of LAT1 and LAT2, during differentiation of PDL fibroblast cells. 4. The expression level of ALP mRNA was gradually increased and the expression level of Col I mRNA was decreased during differentiation of PDL fibroblast cells. 5. The L-leucine transport was reduced by time from the early stage to the late stage in PDL fibroblast cell differentiation. As the results, it is considered that among neutral amino acid transport system L in differentiation of PDL fibroblast cells, the LAT1 has a key role in cell proliferation in the early stage of cell differentiation and the LAT2 has an important role in the late stage of cell differentiation for providing cells with neutral amino acids including several essential amino acids.
Amino Acid Transport System L* ; Amino Acid Transport Systems ; Amino Acids ; Amino Acids, Essential ; Amino Acids, Neutral ; Animals ; Cell Differentiation ; Cell Proliferation ; Dental Cementum ; Fibroblasts* ; Gingiva ; Leucine ; Mice ; Molar ; Periodontal Ligament* ; Periodontium ; RNA, Messenger ; Tooth

The Fanconi syndrome is characterized by generalized disturbance of tubular function. It leads to excessive losses of amino acids, glucose, phosphate, bicarbonate, and other organic and inorganic substrates handled by the proximal tubules. The metabolic consequences are acidosis, hypophosphatemia, hypocalemia, dehydration, rickets, osteomalacia, osteoporosis, and growth retardation. This syndrome may either be congenital or acquired, primary or secondary. Acquired Fanconi syndrome may result from multiple myeloma, Wilsons disease, primary amyloidosis, light chain nephropathy, and heavy metal poisoning such as lead, mercury, and cadmium. A 33-year-old female presented with multiple bone pain, and progressive proximal muscle weakness for 15 months. The blood urea nitrogen, creatinine, calcium, phosphate, and uric acid were 12.1 mg/dL, 1.5 mg/dL, 8.4 mg/dL, 1.8 mg/dL, and 1.7 mg/dL, respectively. The urine volume, protein, calcium, phosphate, and creatinine clearance were 2,330 ml, 343.7 mg, 146 mg, 424 mg, and 44.6 ml/min, respectively in 24 hour collection urine study. The tubular reabsorption rate of phosphate was decreased. In arterial blood gas analysis study, pH was 7.348, bicarbonate was 17.6 mmol/L, which means metabolic acidosis. In chest X-ray, fracture was seen in eighth and ninth left ribs. The whole body bone scan revealed hot uptake at both first and second ribs, right third rib, both eighth and ninth ribs, left sacroiliac joint and right hip joint. Bone densitometry showed moderate osteopenia in spine and femur neck. After NE4Cl loading, the urine pH was decreased below 5.0 at two and third hour, which means proximal renal tubular acidosis. Amino acid such as, hydroxyproline, threonine, serine, asparagine, glutamine excreted much more than normal in 24 hour urine. Bone biopsy showed the presence of increased osteoid volume and osteoid seam width and marked decreased mineral appositional rate as evidence for osteomalacia. The patients symptoms, including bone pain and proximal muscle weakness, were relieved after supplement of calcitonin, Vitamin D and calcium carbonate. We report a case of Fanconi syndrome with hypophosphatemic osteomalacia with brief review of literature.
Acidosis ; Acidosis, Renal Tubular ; Adult ; Amino Acids ; Amyloidosis ; Asparagine ; Biopsy ; Blood Gas Analysis ; Blood Urea Nitrogen ; Bone Diseases, Metabolic ; Cadmium ; Calcitonin ; Calcium ; Calcium Carbonate ; Creatinine ; Dehydration ; Densitometry ; Fanconi Syndrome ; Female ; Femur Neck ; Glucose ; Glutamine ; Hepatolenticular Degeneration ; Hip Joint ; Humans ; Hydrogen-Ion Concentration ; Hydroxyproline ; Hypophosphatemia ; Miners ; Multiple Myeloma ; Muscle Weakness ; Osteomalacia ; Osteoporosis ; Poisoning ; Ribs ; Rickets ; Sacroiliac Joint ; Serine ; Spine ; Thorax ; Threonine ; Uric Acid ; Vitamin D

Most normal cells express L-type amino acid transporter 2 (LAT2). However, L-type amino acid transporter 1 (LAT1) is highly expressed in many tumor cells and presumed to support their increased growth and proliferation. This study examined the effects of JPH203, a selective LAT1 inhibitor, on cell growth and its mechanism for cell death in Saos2 human osteosarcoma cells. FOB human osteoblastic cells and Saos2 cells expressed LAT1 and LAT2 together with their associating protein 4F2 heavy chain, but the expression of LAT2 in the Saos2 cells was especially weak. JPH203 and BCH, a non-selective L-type amino acid transporter inhibitor, potently inhibited L-leucine uptake in Saos2 cells. As expected, the intrinsic ability of JPH203 to inhibit L-leucine uptake was far more efficient than that of BCH in Saos2 cells. Likewise, JPH203 and BCH inhibited Saos2 cell growth with JPH203 being superior to BCH in this regard. Furthermore, JPH203 increased apoptosis rates and formed DNA ladder in Saos2 cells. Moreover, JPH203 activated the mitochondria-dependent apoptotic signaling pathway by upregulating pro-apoptotic factors, such as Bad, Bax, and Bak, and the active form of caspase-9, and downregulating anti-apoptotic factors, such as Bcl-2 and Bcl-xL. These results suggest that the inhibition of LAT1 activity via JPH203, which may act as a potential novel anti-cancer agent, leads to apoptosis mediated by the mitochondria-dependent intrinsic apoptotic signaling pathway by inducing the intracellular depletion of neutral amino acids essential for cell growth in Saos2 human osteosarcoma cells.
Amino Acid Transport Systems* ; Amino Acids, Neutral ; Antigens, CD98 Heavy Chain ; Apoptosis* ; Caspase 9 ; Cell Death ; DNA ; Humans* ; Leucine ; Osteoblasts ; Osteosarcoma*

Circadian Clocks/genetics* ; Reactive Oxygen Species ; Methionine ; Gastrointestinal Microbiome ; Gastrointestinal Tract ; Racemethionine ; Gene Expression

This study was carried out to obtain the basic data for artificial culture of veiled lady mushroom (Dictyophora spp). The optimal conditions for the mycelial growth were 25degrees C and pH 5.0 for all isolates except the optimal temperature of 30degrees C for D. echinovolvata ASI 32002 and Phallus rugulosus . The optimal medium for Dictyophora spp. was PBA (potato bamboo sawdust extract agar) medium. The strain ASI 32002, D. echinovolvata , grew faster than. D. indusiata ASI 32003 and Phallus rugulosus ASI 25007 on the medium. Carbon sources such as glucose, maltose and inuline were favorable for stimulating a mycelial growth of the two strains of ASI 32002 and ASI 32003. Asparagine and glutamine appeared to be favorable to the strain ASI 32002 and ASI 32003, where as alanine, one of nitrogen source also favorable to the strain ASI 32002. The optimum C/N ratio of the two isolates of ASI 32002 and ASI 32003 was about 25 : 1 when 2% glucose as carbon source was mixed with the basal medium. While, in the case of 4% as carbon source, the optimum C/N ratio was about 30 : 1.
Agaricales* ; Alanine ; Asparagine ; Carbon ; Cultural Characteristics* ; Glucose ; Glutamine ; Hydrogen-Ion Concentration ; Inulin ; Maltose ; Nitrogen