Cystine: A covalently linked dimeric nonessential amino acid formed by the oxidation of CYSTEINE. Two molecules of cysteine are joined together by a disulfide bridge to form cystine.Cystinosis: A metabolic disease characterized by the defective transport of CYSTINE across the lysosomal membrane due to mutation of a membrane protein cystinosin. This results in cystine accumulation and crystallization in the cells causing widespread tissue damage. In the KIDNEY, nephropathic cystinosis is a common cause of RENAL FANCONI SYNDROME.Cystine Knot Motifs: Amino acid sequence in which two disulfide bonds (DISULFIDES) and their connecting backbone form a ring that is penetrated by a third disulfide bond. Members include CYCLOTIDES and agouti-related protein.Amino Acid Transport System y+Cystinuria: An inherited disorder due to defective reabsorption of CYSTINE and other BASIC AMINO ACIDS by the PROXIMAL RENAL TUBULES. This form of aminoaciduria is characterized by the abnormally high urinary levels of cystine; LYSINE; ARGININE; and ORNITHINE. Mutations involve the amino acid transport protein gene SLC3A1.Cysteamine: A mercaptoethylamine compound that is endogenously derived from the COENZYME A degradative pathway. The fact that cysteamine is readily transported into LYSOSOMES where it reacts with CYSTINE to form cysteine-cysteamine disulfide and CYSTEINE has led to its use in CYSTINE DEPLETING AGENTS for the treatment of CYSTINOSIS.Cysteine: A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.Amino Acids, SulfurFanconi Syndrome: A hereditary or acquired form of generalized dysfunction of the PROXIMAL KIDNEY TUBULE without primary involvement of the KIDNEY GLOMERULUS. It is usually characterized by the tubular wasting of nutrients and salts (GLUCOSE; AMINO ACIDS; PHOSPHATES; and BICARBONATES) resulting in HYPOKALEMIA; ACIDOSIS; HYPERCALCIURIA; and PROTEINURIA.Cyclotides: A continuous circle of peptide bonds, typically of 2-3 dozen AMINO ACIDS, so there is no free N- or C-terminus. They are further characterized by six conserved CYSTEINE residues that form CYSTINE KNOT MOTIFS.Glutathione: A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.Disulfides: Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.Cystamine: A radiation-protective agent that interferes with sulfhydryl enzymes. It may also protect against carbon tetrachloride liver damage.Amino Acid Transport Systems, Neutral: Amino acid transporter systems capable of transporting neutral amino acids (AMINO ACIDS, NEUTRAL).Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Methionine: A sulfur-containing essential L-amino acid that is important in many body functions.Amino Acid Transport Systems, Basic: Amino acid transporter systems capable of transporting basic amino acids (AMINO ACIDS, BASIC).Oldenlandia: A plant genus of the family RUBIACEAE. Some species are used as an ingredient in Chinese and African traditional medicines. Members contain kalata B1, a macrocyclic peptide.Cystine-Knot Miniproteins: A structurally-related family of small proteins that form a stable tertiary fold pattern which is supported by a series of disulfide bonds. The arrangement of disulfide bonds between the CYSTEINE moieties results in a knotted structure which is unique to this family of proteins.Coprophagia: Eating of excrement by animal species.Sulfhydryl Compounds: Compounds containing the -SH radical.MaleatesMetabolic Networks and Pathways: Complex sets of enzymatic reactions connected to each other via their product and substrate metabolites.Sulfur: An element that is a member of the chalcogen family. It has an atomic symbol S, atomic number 16, and atomic weight [32.059; 32.076]. It is found in the amino acids cysteine and methionine.Urinary Calculi: Low-density crystals or stones in any part of the URINARY TRACT. Their chemical compositions often include CALCIUM OXALATE, magnesium ammonium phosphate (struvite), CYSTINE, or URIC ACID.Dictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.Amino Acids, Essential: Amino acids that are not synthesized by the human body in amounts sufficient to carry out physiological functions. They are obtained from dietary foodstuffs.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Escherichia coli Infections: Infections with bacteria of the species ESCHERICHIA COLI.Veterinary Medicine: The medical science concerned with the prevention, diagnosis, and treatment of diseases in animals.Veterinary Drugs: Drugs used by veterinarians in the treatment of animal diseases. The veterinarian's pharmacological armamentarium is the counterpart of drugs treating human diseases, with dosage and administration adjusted to the size, weight, disease, and idiosyncrasies of the species. In the United States most drugs are subject to federal regulations with special reference to the safety of drugs and residues in edible animal products.Education, Veterinary: Use for general articles concerning veterinary medical education.Surgery, Veterinary: A board-certified specialty of VETERINARY MEDICINE, requiring at least four years of special education, training, and practice of veterinary surgery after graduation from veterinary school. In the written, oral, and practical examinations candidates may choose either large or small animal surgery. (From AVMA Directory, 43d ed, p278)Schools, Veterinary: Educational institutions for individuals specializing in the field of veterinary medicine.Pathology, Veterinary: The field of veterinary medicine concerned with the causes of and changes produced in the body by disease.Veterinarians: Individuals with a degree in veterinary medicine that provides them with training and qualifications to treat diseases and injuries of animals.Agouti-Related Protein: A secreted protein of approximately 131 amino acids that is related to AGOUTI SIGNALING PROTEIN and is also an antagonist of MELANOCORTIN RECEPTOR activity. It is expressed primarily in the HYPOTHALAMUS and the ADRENAL GLAND. As a paracrine signaling molecule, AGRP is known to regulate food intake and body weight. Elevated AGRP has been associated with OBESITY.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Bibliometrics: The use of statistical methods in the analysis of a body of literature to reveal the historical development of subject fields and patterns of authorship, publication, and use. Formerly called statistical bibliography. (from The ALA Glossary of Library and Information Science, 1983)Access to Information: Individual's rights to obtain and use information collected or generated by others.Journal Impact Factor: A quantitative measure of the frequency on average with which articles in a journal have been cited in a given period of time.gamma-Glutamyltransferase: An enzyme, sometimes called GGT, with a key role in the synthesis and degradation of GLUTATHIONE; (GSH, a tripeptide that protects cells from many toxins). It catalyzes the transfer of the gamma-glutamyl moiety to an acceptor amino acid.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Kidney Tubules: Long convoluted tubules in the nephrons. They collect filtrate from blood passing through the KIDNEY GLOMERULUS and process this filtrate into URINE. Each renal tubule consists of a BOWMAN CAPSULE; PROXIMAL KIDNEY TUBULE; LOOP OF HENLE; DISTAL KIDNEY TUBULE; and KIDNEY COLLECTING DUCT leading to the central cavity of the kidney (KIDNEY PELVIS) that connects to the URETER.Absorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Lysine: An essential amino acid. It is often added to animal feed.Kidney Calculi: Stones in the KIDNEY, usually formed in the urine-collecting area of the kidney (KIDNEY PELVIS). Their sizes vary and most contains CALCIUM OXALATE.Renal Colic: A severe intermittent and spasmodic pain in the lower back radiating to the groin, scrotum, and labia which is most commonly caused by a kidney stone (RENAL CALCULUS) passing through the URETER or by other urinary track blockage. It is often associated with nausea, vomiting, fever, restlessness, dull pain, frequent urination, and HEMATURIA.Kidney Tubules, Proximal: The renal tubule portion that extends from the BOWMAN CAPSULE in the KIDNEY CORTEX into the KIDNEY MEDULLA. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the U-shaped LOOP OF HENLE.Inappropriate ADH Syndrome: A condition of HYPONATREMIA and renal salt loss attributed to overexpansion of BODY FLUIDS resulting from sustained release of ANTIDIURETIC HORMONES which stimulates renal resorption of water. It is characterized by normal KIDNEY function, high urine OSMOLALITY, low serum osmolality, and neurological dysfunction. Etiologies include ADH-producing neoplasms, injuries or diseases involving the HYPOTHALAMUS, the PITUITARY GLAND, and the LUNG. This syndrome can also be drug-induced.