Studies on the possibility of histidine biosynthesis from histidinol, imidazolepyruvic acid, imidazoleacetic acid, and imidazolelactic acid by mixed ruminal bacteria, protozoa, and their mixture in vitro

Abstract

The possibility of histidine (His) synthesis using a main biosynthetic pathway involving histidinol (HDL) and also the recycling capability of imidazolic compounds such as imidazolepyruvic acid (ImPA), imidazoleacetic acid (ImAA), and imidazolelactic acid (ImLA) to produce His were investigated using mixed ruminal bacteria (B), protozoa (P), and a mixture of both (BP) in an in vitro system. Rumen microorganisms were anaerobically incubated at 39 degrees C for 18 h with or without each substrate (2 mM) mentioned. His and other related compounds produced in both the supernatants and hydrolyzates of the incubation were analyzed by high-performance liquid chromatography. B, P, and BP suspensions failed to show His synthesizing ability when incubated with HDL. His was synthesized from ImPA by B, P, and BP. Expressed in units "per gram of microbial nitrogen (MN)", ImPA disappearance was greatest in B (72.7 micromol/g MN per hour), followed by BP (33.13 micromol/g MN per hour) and then P (18.6 micromol/g MN per hour) for the 18-h incubation period. The production of His from ImPA in B (240.0, 275.9, and 261.2 micromol/g MN in 6, 12, and 18 h incubation, respectively) was about 3.5 times higher than that in P (67.3, 83.8, and 72.7 micromol/g MN in 6, 12, and 18 h incubation, respectively). Other metabolites produced from ImPA were ImLA, ImAA, histamine (HTM), and urocanic acid (URA), found in all microbial suspensions. ImLA as a substrate remained without diminution in all microbial suspensions. Although ImAA was found to be degraded to a small extent (3.4-6.3%) only after 18 h incubation, neither His nor other metabolites were detected on the chromatograms. These results have been demonstrated for the first time in rumen microorganisms and suggest that His may be an essential amino acid for rumen microorganisms.

Metabonomics analysis of kidneys in rats administered with chronic low‐dose cadmium by ultra‐performance liquid chromatography‐mass spectrometry

“…Imidazole lactic acid is one of the metabolites of histidine (Wadud, Onodera, & Or-Rashid, 2001). In mammals, histidine can be metabolized to imidazole lactic acid, imidazole pyruvic acid and imidazole acetic acid, and these metabolites can be excreted through the urine (Block, Westhoff, & Steele, 1967).…”

Separation assay of histamine and its metabolites in biological specimens

“…histidine, histidinol, urocanic acid and imidazolepyruvic acid) in rumen fluid were performed under two different chromatographic conditions on a Lichrospher 100 NH 2 column (Wadud et al, 2000(Wadud et al, , 2001. The mobile-phase for the isocratic elution in the first chromatographic condition was 67 mM potassium phosphate (pH 6.45) and 90% acetonitrile in water (21:79), while an acetonitrile gradient in 63 mM potassium phosphate (pH 3.0), prepared by the addition of 60 mM phosphoric acid, was used for the second system.…”

Essentiality of Histidine in Ruminant and Other Animals Including Human Beings

“…In order to prove the above hypothesis, enzymatic experiment was conducted in the author's laboratory as reported recently (Wadud et al, 2001b). Namely, histidinol dehydrogenase (HLDase) (EC 1.1.1.23), which catalyzes the reaction from histidinol to histidine at the final step of the histidine de novo synthetic pathway as mentioned above, was chosen to be examined with cattle liver and kidney, since in any case it is necessary to know at first the enzyme activity of the final step of the system as has been tested for proving the ability of histidine synthesis in rumen microorganisms (Wadud et al 2001a). HLDase activity was assayed by determining increase in histidine with crude enzyme solution prepared from liver and kidney collected from Japanese black cattle (delivered cattle) immediately after slaughter.…”

“…(partly cited from Wadud et al 2001a) in younger animals, while production of histidine may increase in proportion to growing stages, if the HLDase activity per unit weight of tissue does not vary largely with growth. Therefore, it is considered that the relationship between production and requirement (supply and demand) of histidine vary with growing stages.…”

“…In ruminant animals, however, EAAs have never been fully established (Buttery and Foulds, 1985) due to the technical uneasiness in the cause of the presence of rumen microorganisms. In this regard, we have recently achieved a strong suggestion that especially 'histidine' among ten EAAs for immature rats could be synthesized on a large scale by cattle organs (Wadud et al, 2001b;Wadud et al, 2002), which had been hinted in the course of the experiments on amino acid metabolism by (Wadud et al, 2001a) and on evaluation of nutritive values of rumen microorganisms (Onodera and Koga, 1987). Incidentally, histidine is the only amino acid on which disputes have continued for as long a period as nearly 25 years especially with regard to its essentiality in adult human (Fuller and Garlick, 1994;Metges et al, 1999).…”