Thromboxane A2 and prostaglandin F2alpha mediate inflammatory tachycardia

Systemic inflammation induces various adaptive responses including tachycardia. Although inflammation-associated tachycardia has been thought to result from increased sympathetic discharge caused by inflammatory signals of the immune system, definitive proof has been lacking. Prostanoids, including prostaglandin (PG) D(2), PGE(2), PGF(2alpha), PGI(2) and thromboxane (TX) A(2), exert their actions through specific receptors: DP, EP (EP(1), EP(2), EP(3), EP(4)), FP, IP and TP, respectively. Here we have examined the roles of prostanoids in inflammatory tachycardia using mice that lack each of these receptors individually. The TXA(2) analog I-BOP and PGF(2alpha) each increased the beating rate of the isolated atrium of wild-type mice in vitro through interaction with TP and FP receptors, respectively. The cytokine-induced increase in beating rate was markedly inhibited in atria from mice lacking either TP or FP receptors. The tachycardia induced in wild-type mice by injection of lipopolysaccharide (LPS) was greatly attenuated in TP-deficient or FP-deficient mice and was completely absent in mice lacking both TP and FP. The beta-blocker propranolol did not block the LPS-induced increase in heart rate in wild-type animals. Our results show that inflammatory tachycardia is caused by a direct action on the heart of TXA(2) and PGF(2alpha) formed under systemic inflammatory conditions.     

Effect of herb supplement on hepatic enzyme activities in ddY mice.

Plasma glucose and lipid concentrations and hepatic enzyme activities were measured in male ddY mice supplemented with the herb, Echevaria glauca, to examine the effect of herbal treatment. In mice supplemented with the herb, plasma triglyceride (TG) and free fatty acid (FFA) concentrations decreased and hepatic glycolytic enzyme and glutathione peroxidase (GSHpx) activities increased significantly compared with those in the non-treated control mice. These increases in hepatic enzyme activities were not fully dose-dependent, however the higher dose and longer duration with herb supplement induced increases in the enzyme activities. It was found that dietary herb supplement caused an acceleration of hepatic function, judged by increased activities of glycolytic enzyme and GSHpx in ddY mice.     

Sequencing and expression of the L-phenylalanine oxidase gene from Pseudomonas sp. P-501. Proteolytic activation of the proenzyme

The nucleotide sequence encoding L-phenylalanine oxidase (deaminating and decarboxylating) (PAO) from Pseudomonas sp. P-501 was determined. The open reading frame is arranged in the order of prosequence, alpha subunit, dipeptide and beta subunit from the 5'- to 3'-end. Expression of the gene in Escherichia coli showed that without the prosequence, PAO is produced in small quantity as a soluble form with no visible absorption, but with the prosequence (proPAO), PAO is highly expressed and yellow. The purified proPAO contained one mol of FAD per mol of proPAO polypeptide, but had no catalytic activity. Treatment of proPAO with a mixture of Pronase and trypsin converted the noncatalytic proPAO to the catalytic form, and the Pronase-trypsin-treated proPAO showed kinetic and spectral properties comparable to the native enzyme. These results suggest that in Pseudomonas, PAO is expressed as a proenzyme that is processed by proteolysis to the active form.     

Phylogeography and genetic ancestry of tigers (Panthera tigris)

Eight traditional subspecies of tiger (Panthera tigris),of which three recently became extinct, are commonly recognized on the basis of geographic isolation and morphological characteristics. To investigate the species' evolutionary history and to establish objective methods for subspecies recognition, voucher specimens of blood, skin, hair, and/or skin biopsies from 134 tigers with verified geographic origins or heritage across the whole distribution range were examined for three molecular markers: (1) 4.0 kb of mitochondrial DNA (mtDNA) sequence; (2) allele variation in the nuclear major histocompatibility complex class II DRB gene; and (3) composite nuclear microsatellite genotypes based on 30 loci. Relatively low genetic variation with mtDNA,DRB,and microsatellite loci was found, but significant population subdivision was nonetheless apparent among five living subspecies. In addition, a distinct partition of the Indochinese subspecies P. t. corbetti in to northern Indochinese and Malayan Peninsula populations was discovered. Population genetic structure would suggest recognition of six taxonomic units or subspecies: (1) Amur tiger P. t. altaica; (2) northern Indochinese tiger P. t. corbetti; (3) South China tiger P. t. amoyensis; (4) Malayan tiger P. t. jacksoni, named for the tiger conservationist Peter Jackson; (5) Sumatran tiger P. t. sumatrae; and (6) Bengal tiger P. t. tigris. The proposed South China tiger lineage is tentative due to limited sampling. The age of the most recent common ancestor for tiger mtDNA was estimated to be 72,000-108,000 y, relatively younger than some other Panthera species. A combination of population expansions, reduced gene flow, and genetic drift following the last genetic diminution, and the recent anthropogenic range contraction, have led to the distinct genetic partitions. These results provide an explicit basis for subspecies recognition and will lead to the improved management and conservation of these recently isolated but distinct geographic populations of tigers.     

Induction of antibacterial activity in the haemolymph of the silkworm, Bombyx mori, by injection of formalin-treated Escherichia coli K-12 in the anterior and posterior body part of the ligated larvae.

1. Induction of antibacterial activity was investigated in the ligated fifth instar larvae of the silkworm, Bombyx mori, by injection of formalin-treated Escherichia coli K-12 into the haemocoel in the anterior and in the posterior body part, followed by activity determination by inhibition zone assay of the haemolymph at 12 and 24 hr after immunization. 2. At 12 hr after immunization, high antibacterial activity, approximately 6.8-7.5 mm in the anterior body part and 4.5-6.4 mm in the posterior body part in diameter of a clear zone (2.0 mm for no activity) was detectable in day 3 larvae. This result was in good contrast to expression of lectin gene in the ligated flesh fly, Sarcophaga peregrena (Shiraishi and Natori, 1988, FEBS Lett. 232, 163-166), in which only the anterior part of insect responded to stimulus of injury. 3. Antibacterial activity at 24 hr after immunization in days 3 or 4 ligated larvae was lower than that at 12 hr; 4.0-4.5 mm of activity was observed in the anterior body part, and no activity was observed in day 3 ligated larvae in the posterior body part. 4. Acid polyacrylamide gel electrophoresis of the haemolymph of immunized insects followed by overlay assay showed that the size of antibacterial activity bands were similar between the haemolymph from 12 hr and from 24 hr, and between the anterior and the posterior body part. This result was contradictory to the observation of activity by inhibition zone assay. The activity bands were associated with peptides that were similar to cecropin-like peptides A and B in the silkworm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection of Hsp60 (GroEL)-like proteins in Vibrio parahaemolyticus and vibrio species by Western immunoblotting analysis

Detection of heat shock proteins in Vibrio parahaemolyticus was investigated by SDS-PAGE and Western immunoblotting procedure using an anti-Hsp 60 antibody. Results indicate that V. parahaemolyticus elicited at least one Hsp 60 (GroEL)-like protein with apparent molecular weight of about 58 000 (58 kDa) when submitted to a heat shift from 30 to 42C. Kanagawa phenomenon-positive and -negative strains of V. parahaemolyticus responded the same way. Six other Vibrio species also showed an increased synthesis of GroEL-like (58 kDa) protein after heat shock, while synthesis of 58 kDa protein of V. alginolyticus was at a similar level before and after heat shock. Vibrio nereis showed an increased synthesis of a 60 kDa GroEL-like protein.     

Reduced DNase I sensitivity of the rearranged c-myc gene in somatic cell hybrids between murine plasmacytoma cells and fibroblasts

In mouse plasmacytoma (MPC) S194, the rearranged c-myc gene was much more sensitive to DNase I digestion than the nonrearranged gene. The sensitivity of the rearranged c-myc was markedly reduced to the same extent as that of the nonrearranged one in hybrids between the MPC cells and the fibroblasts, but not in a hybrid between the MPC and the spleen cells. These results suggest that trans-acting factors in fibroblasts alter the DNase I-sensitive structure of the rearranged c-myc gene.