Immunogenicity of Leucocytozoon caulleryi sporozoites and their reactivity with specific immune sera

The immunogenicity of Leucocytozoon caulleryi sporozoites for chickens and their reactivity in vitro with specific immune sera were studied. Almost all of the chickens that had been immunized with the sporozoite antigens survived the sporozoite challenge. The degree of parasitemia observed in the immunized chickens was significantly lower than that found in the nonimmunized chickens. Specific antibodies against sporozoites were tested by the circumsporozoite precipitation (CSP) reaction. Antibodies were demonstrated in the sera of chickens that had been immunized with the sporozoite antigens or chickens that had recovered from a primary infection with L. caulleryi sporozoites. When viable mature sporozoites were incubated in vitro with serum from immune chickens, agglutination and a long, thread-like precipitate at one end of the sporozoite could be seen within a few minutes under a phase-contrast microscope. The effects of specific immune serum on the infectivity of sporozoites were examined by the sporozoite neutralization activity (SNA) test. Sporozoites that had been incubated in vitro with serum from immune chickens lost their infectivity to chickens. The CSP reaction and the SNA test in L. caulleryi infection were stage- and species-specific.

Detection of HBV-DNA and HCV-RNA viral sequences by polymerase chain reaction in selected Kenyan samples and the relationship to HBV seromarkers

We undertook a study on selected samples from patients who had presented with viral hepatitis and conditions of the liver (liver cirrhosis, chronic hepatitis and hepatocellular carcinoma). Diagnosis, screening and confirmation for viral hepatitis was done using a battery of techniques: ultrasound, conventional serological methods (Hepatitis B surface Antigen [HBsAg] - Reverse Passive Haemagglutination [RPHA], Hepatitis B core Antibody [HBcAb] - Passive Haemagglutination [PHA], Alpha-feto Protein - RPHA), Hepatitis B e Antigen/Antibody [HBeAg/Ab] - Radioimmunoassay [RIA], Hepatitis C antibody [HCV-Ab] - Enzyme Immunosorbent Assay [EIA]. Due to the high specificity and sensitivity of the Polymerase Chain Reaction technique [PCR] in detecting the viral genomes, it was used to establish the presence of the HBV-DNA and HCV-RNA to correlate the serological diagnosis of their respective seromarkers. A total of 39 serum samples were tested comprising 11 blood donors, 8 chronic liver disease patients and 20 hepatocellular carcinoma cases. 4/19 (21%) HCV-antibody (C-l) reactive samples were found to be positive for HCV-RNA by PCR. 14 of the 19 (73.7%) including the 4 HCV-RNA positive cases tested positive for HBcAb. 6 of 11 (55%) HBsAg positive cases also tested positive for HBV-DNA by PCR, In 8 of 20 (40%) hepatocellular carcinoma cases, no aetiological role could be assigned to hepatitis B or C as only HBcAb was demonstrated in those cases.

Rapid expulsion of the intestinal trematodes Echinostoma trivolvis and E. caproni from C3H mice by trapping with increased goblet cell mucins

Echinostoma trivolvis (Cort, 1914) adults were rejected from C3H mice by 15 days post-exposure, corresponding to the increase in the number of goblet cells. Homologous and heterologous infections with the allopatric species E. caproni (Richard, 1964) were used to confirm the effect of increased secretion of goblet cell mucins in rejecting metacercariae of challenge infections of E. trivolvis or E. caproni on days 10, 16 and 20 p.i. after primary infections of E. trivolvis metacercariae. Five-day-old juveniles of E. trivolvis and E. caproni, which were recovered from C3H mice or hamsters, were also used for challenge infections on day 10 p.i. The metacercariae and juveniles, which were challenged homologously and heterologously on day 10 p.i., were almost all expelled. The metacercariae of E. trivolvis, which were challenged homologously on day 16, were completely rejected, but only a few challenged metacercariae of E. caproni in heterologous infection were recovered. Considerable numbers of E. caproni were recovered when challenge infections with the metacercariae were done on day 20 p.i., while only a small number of E. trivolvis was recovered. All controls without primary infections showed a recovery rate of over 50% of the worms. These results indicate that increased secretion of mucins by hyperplastic goblet cells associated with primary infections of E. trivolvis may be responsible for the expulsion of worms challenged homologously with E. trivolvis and heterologously with E. caproni from the mouse host.

Caffeine induces ventricular tachyarrhythmias possibly due to triggered activity in rabbits in vivo

Caffeine induces delayed afterdepolarizations (DADs) and triggered activity in isolated cardiac tissue. We investigated the ability of caffeine to induce triggered ventricular arrhythmias in rabbits in vivo. During continuous infusion of caffeine at doses of 0.3 or 1.0 mg/kg per min, ventricular pacing was performed with 50 stimuli with a cycle length of 220 msec (basic pacing train) every 5 min until ventricular tachycardia (VT) was induced. The effects of programmed stimulation and pharmacologic agents on the induction of ventricular ectopic beats (VEBs) were examined. Pacing protocols were carried out in the presence of vagal-induced slowing of sinus rhythm. VT was induced by a basic pacing train during the infusion of caffeine at 1.0 mg/kg per min, but not at 0.3 mg/kg per min. An increase in the pacing rate or the number of stimuli resulted in 1) a decrease in the first postpacing interval, and 2) an increase in the number of postpacing VEBs. Induction of VT was suppressed by intravenous bolus injections of verapamil, propranolol and adenosine. At the time of the initial induction of VT, the plasma concentration of caffeine was 87 +/- 2 micrograms/ml and the plasma level of norepinephrine increased from 666 +/- 166 pg/ml at baseline to 1121 +/- 245 pg/ml. These results suggest that catecholamine-associated triggered activity may be responsible for caffeine-induced VT.

[A case of mitochondrial encephalomyopathy (MELAS)]

Mitochondrial encephalomyopathy is a hereditary syndrome showing impairment of muscle and the central nervous system. In this disorder, the following three syndromes have been identified on the basis of characteristic symptoms: Kearns-Sayre syndrome (KSS), mitochondrial encephalomyopathy with lactic acidosis, and stroke-like episodes (MELAS), and myotonic epilepsy with ragged-red fibers (MERRF). In this report, we describe a case of mitochondrial encephalomyopathy with renal disease. A 25-year-old man was referred to our hospital in May, 1992 for evaluation of long-standing proteinuria. He had a small stature, exotropia and no pretibial edema. No mental retardation was observed. Urinary protein excretion was 2.0 g/day and urine sugar was negative. Laboratory examination revealed a serum urea nitrogen 19 mg/dl, and a creatinine value of 1.5 mg/dl. Creatinine clearance was 45.8 ml/min. His serum and spinal fluid lactate value were elevated. Biopsied muscle showed an absence of ragged-red fibers, and the presence of an A-to-G point mutation at nucleotide pari 3243 in the mitochondrial tRNA(Leu(UUR)) in peripheral blood leucocytes. He was thought to have MELAS. On the renal biopsy specimens, light microscopic examinations showed minor glomerular abnormalities with two glomerular collapses and tubulo-interstitial damage. Electron microscopic examinations showed partial thickening of the glomerular basement membrane. We report here this rare case of MELAS with renal disease, and also review seventeen cases of mitochondrial encephalopathy associated with renal disease. The existence of a relationship between mitochondrial disorder and renal damage remains obscure.

Two types of parenchymal cells in the lung fluke Paragonimus ohirai (Digenea: Troglotrematidae) characterized by the cytochemistry of their mitochondria

Morphology and respiratory function were studied in situ and in the isolated mitochondria of Paragonimus ohirai. Two types of parenchymal cells (i.e., Pc1 and Pc2 cells), whose mitochondria differ in terms of morphology and staining for cytochrome c oxidase activity, were found in fluke tissues. Enzymatic and spectrophotometric analyses of the isolated mitochondria showed that fluke mitochondria possess both aerobic and anaerobic respiratory chains. These results suggest that there are two mitochondrial populations in fluke parenchymal cells, one possessing an aerobic respiratory chain and the other an anaerobic respiratory chain.

Molecular genetic analysis of clear cell adenocarcinomas of the vagina and cervix associated and unassociated with diethylstilbestrol exposure in utero

BACKGROUND

Prenatal exposure to the synthetic estrogen diethylstilbestrol (DES) is associated with the subsequent development of clear cell adenocarcinoma of the lower reproductive tract in young women, and data concerning the molecular genetic alterations involved in the etiology of this tumor type have not previously been reported. Such knowledge would be of potential value by providing insight into the molecular mechanisms of hormonal carcinogenesis in general, as well as by suggesting molecular markers for risk assessment in the estrogen-exposed population.

METHODS

A total of 24 samples of clear cell adenocarcinoma of the vagina or cervix, 16 associated with exposure in utero to DES and 8 with no history of DES exposure, were obtained as archival fixed and embedded tissue specimens. DNA was purified from these tissues and used to examine a number of biologically plausible molecular genetic endpoints for tumor specific alterations.

RESULTS

No evidence was found for mutations in the K-ras or H-ras protooncogenes, the Wilms' tumor (WT1) tumor suppressor gene, or the estrogen receptor gene. Sporadic overexpression of the p53 tumor suppressor gene was detected in some tumor cell nuclei by immunohistochemistry, but in the absence of detectable p53 gene mutation. Genetic instability as manifested by somatic mutation of microsatellite repeats was widespread in these tumors, with evidence of microsatellite instability in all DES-associated tumors examined, and in 50% of those tumors not associated with DES exposure.

CONCLUSIONS

These data are consistent with the hypothesis that the induction of genomic instability may be an important mechanism of DES-induced carcinogenesis.

[Effects of exercise on mitral regurgitation in healthy subjects]

Transthoracic echocardiography including color Doppler echocardiography and graded exercise (supine bicycle ergometer) were performed to examine both the changes of mitral regurgitation (MR) flow during exercise and the effects of cathecholamine on the MR flow in 20 young males (mean age 19 years) and 9 male long-distance runners (mean age 20 years) with presumably normal hearts. MR flow was detected in 13 of the 20 young males at rest. The severity of MR was mild in 12 subjects, and moderate in 1. After exercise, MR flow vanished in 4 of the 13 subjects (group B). In the other nine subjects, MR flow lasted during and after exercise (group A). In the seven subjects without MR flow at rest, MR flow did not appear during and after exercise (group C). Group A had significantly lower left ventricular ejection fraction than group C at rest (A 64.9 +/- 4.25%, B 69.4 +/- 4.32%, C 73.9 +/- 3.46%; p < 0.05). However, no significant differences were observed in other echocardiographic parameters (including left ventricular end-diastolic dimension, mitral annulus diameter and left atrial diameter), heart rate and serum cathecholamine levels between the three groups before and after exercise. In the nine male long-distance runners, MR flow was detected in six of nine subjects at rest. The severity of MR was mild in all subjects. After exercise, MR flow vanished in two of these six subjects (group A). In the other four subjects, MR flow lasted during and after exercise (group B). In three subjects without MR flow at rest, MR flow did not appear during and after exercise (group C). There were no significant differences in echocardiographic parameters, heart rate and serum cathecholamine levels between the three groups before and after exercise. These data suggest that MR flow detected in healthy subjects correlates with tension and contractility of papillary muscle.

Determination of the O/M ratios of polynary uranium oxides by Ce(IV)-Fe(II) back titration after dissolution in mixed sulphuric and phosphoric acids

Uranium (IV) in polynary uranium oxides is determined after the solid has been dissolved in a warm mixed solution of sulphuric and phosphoric acids containing excess Ce(IV). The latter is titrated with a Fe(II) standard solution using ferroin as indicator. This method is especially effective for (mixed) uranium oxides which are difficult to dissolve in hot Ce(IV) sulphuric acid. The standard deviation of the determined x value in polynary oxides is estimated to be below +/- 0.004 for samples of 10-30 mg.

Notched T wave as evidence of autonomic nervous lability in Duchenne progressive muscular dystrophy

We investigated the significance of notched T waves on the ECG in 30 patients with Duchenne progressive muscular dystrophy (DMD) and 50 age-matched controls using noninvasive cardiovascular examinations and measurement of urinary catecholamines. Notched T waves were more frequently observed in patients with DMD than in control subjects (46.7% vs. 20.0%, p < 0.05). Moreover, their frequency was age-independent in DMD, whereas they decreased with age in controls. Patients with notched T waves showed significantly increased heart rate, prolonged QTc and augmented excretion of urinary adrenaline compared with patients without them. There were no significant differences in casual BP or incidences of characteristic UCG abnormalities, such as mitral valve prolapse, and ECG abnormalities, such as tall R waves in the right precordial leads, between DMD patients with and without notched T waves. These findings suggest that notched T waves are associated with accelerated sympathetic nervous activity rather than progressive cardiac involvement in DMD.

Coronary dilating effects of intracoronary nicorandil. Comparison with isosorbide dinitrate

Although nicorandil, N-(2-hydroxyethyl) nicotinamide dinitrate, is a nitrate ester, its cardiovascular action differs from that of nitrate compounds in several aspects. In this quantitative angiographic study, the acute coronary dilating effect of intracoronary nicorandil (0.25, 0.50, 1.0 mg) was compared with that of isosorbide dinitrate (ISDN; 1.0 mg) in 46 patients with or without ischemic heart disease (IHD). Dose-dependent right coronary dilating action was observed by intracoronary administration of nicorandil without any adverse effects. The same degree of right coronary dilation was achieved by the intracoronary application of equivalent doses of ISDN. We conclude that intracoronary administration of nicorandil is beneficial for the supportive treatment of IHD during coronary artery investigation and intervention without the risk of severe systemic hypotension.

A comparison of Echinostoma trivolvis and E. caproni using random amplified polymorphic DNA analysis

The random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) technique was applied to two closely-related echinostome species, Echinostoma trivolvis and E. caproni, demonstrate interspecific polymorphisms of genomic DNA. Band patterns generated using five individual primers showed that these two echinostomes were genetically distinct, although they share genomic DNA to some extent.

Cytochemical localization of cytochrome c oxidase activity in mitochondria in the tegument and tegumental and parenchymal cells of the trematodes Echinostoma trivolvis, Zygocotyle lunata, Schistosoma mansoni, Fasciola gigantica and Paragonimus ohirai

Cytochrome c oxidase in the mitochondria of the tegument and tegumental and parenchymal cells was examined cytochemically in Echinostoma trivolvis, Zygocotyle lunata, Schistosoma mansoni, Fasciola gigantica and Paragonimus ohirai, trematodes that inhabit different sites in their vertebrate hosts. Clear differences in enzyme activity occurred in the mitochondria of these species, probably reflecting the different energy metabolisms of these worms. Marked aerobic metabolism occurred in S. mansoni and P. ohirai adults that inhabit the host mesenteric veins and the lungs, respectively. The tegument and parenchymal cells of S. mansoni possess relatively few, small mitochondria with tabular cristae which are heavily reactive for cytochrome c oxidase. In P. ohirai, the activity for cytochrome c oxidase in tegumental mitochondria increased gradually from juveniles to adults, reflecting that the respiratory activity increased with growth and the aerobic metabolism is activated when the worms reach the lung. P. ohirai juveniles and adults had two types of mitochondria with different shapes and enzyme activities that were located in two different types of parenchymal cells. The intestinal species, E. trivolvis had mitochondria in the basal aspect of the tegument, and some variations in enzyme activity of their mitochondria in the tegumental and parenchymal cells were observed, suggesting that they possess both aerobic and anaerobic metabolic systems. Z. lunata that live in rodent caeca are devoid of mitochondria in the tegument and have many characteristic mitochondria with undeveloped cristae in the parenchymal cells. Mitochondria of F. gigantica showed weak or no activity for cytochrome c oxidase, suggesting that the worm is well-adapted to an anaerobic environment in the host bile duct.

Cloning and sequencing of some genes responsible for porphyrin biosynthesis from the anaerobic bacterium Clostridium josui

The 6.2-kbp DNA fragment encoding the enzymes in the porphyrin synthesis pathway of a cellulolytic anaerobe, Clostridium josui, was cloned into Escherichia coli and sequenced. This fragment contained four hem genes, hemA, hemC, hemD, and hemB, in order, which were homologous to the corresponding genes from E. coli and Bacillus subtilis. A typical promoter sequence was found only upstream of hemA, suggesting that these four genes were under the control of this promoter as an operon. The hemA and hemD genes cloned from C. josui were able to complement the hemA and hemD mutations, respectively, of E. coli. The COOH-terminal region of C. josui HemA and the NH2-terminal region of C. josui HemD were homologous to E. coli CysG (Met-1 to Leu-151) and to E. coli CysG (Asp-213 to Phe-454) and Pseudomonas denitrificans CobA, respectively. Furthermore, the cloned 6.2-kbp DNA fragment complemented E. coli cysG mutants. These results suggested that both C. josui hemA and hemD encode bifunctional enzymes.

Relation between QT and RR intervals in patients with bradyarrhythmias

OBJECTIVE

To investigate the relation between QT and RR intervals in the sick sinus syndrome or high degree atrioventricular block.

PATIENTS

32 patients with episodes of prolonged RR intervals (> or = 2.6 s) on Holter electrocardiographic recordings.

DESIGN

QT and RR intervals were measured manually every 100 to 150 beats on electrocardiographic strips reprinted from the Holter tape over 24 hours. The slope of the QT/RR relation was determined by the linear regression equation for RR intervals < or = 1.4 s (slope 1) and > 1.4 s (slope 2).

RESULTS

Slope 2 (0.0068 (0.0030)) was significantly lower than slope 1 (0.0824 (0.0059), P < 0.0001) in the overall patient population. Slopes 1 and 2 were significantly lower (P < 0.001) in the 23 patients with QT intervals at the preceding RR interval of 1 s (QT1s) of < 0.44 s (0.0692 (0.0053) and 0.0019 (0.0030), respectively) than in the nine patients with QT1s intervals > or = 0.44 s (0.1159 (0.0091) and 0.0194 (0.0055), respectively). Slopes 1 and 2 correlated positively with QT1s interval in all patients.

CONCLUSIONS

The QT/RR relation was comparatively flat when the RR interval was prolonged. Patients with prolonged QT intervals showed exaggerated prolongation of the QT interval with prolonged cycle lengths when compared with patients with normal QT intervals.

Effects of ajmaline on non-sodium ionic currents in guinea pig ventricular myocytes

The lack of currently available data stimulated us to investigate the electrophysiological effects of ajmaline, a classical class Ia antiarrhythmic agent, on various currents responsible for the action potential plateau and repolarization phases. The whole cell patch clamp recording technique was applied to guinea pig ventricular myocytes. Ajmaline suppressed the Ca2+ current (Ica) in a dose-dependent manner (Kd = 1.2 x 10(-5) M) without affecting the steady-state inactivation kinetics and the voltage dependency of the current-voltage relationship. Ajmaline inhibited the inward portion of the inward rectifying K+ current (IKl). Ajmaline decreased the delayed rectifier K+ current (IK) without altering the activation or deactivation time courses. All these inhibitory effects of ajmaline prolonged the action potential duration in a dose dependent manner. The inhibitory actions of ajmaline on the action potential upstroke and various currents responsible for the plateau and repolarization may contribute to the observed suppression of depolarization-induced abnormal automaticities by this agent.

[A case report of the atypical tuberculosis associated with AIDS]

A 49-year-old Japanese male who had been imprisoned for five years then lived with other men complained of fever, constitutional symptoms and a 12 kg weight loss over four-month period. He was referred to us as his gastric washings were positive for acid-fast bacilli (AFB). Chest X-ray showed patchy, infiltrative small shadows primarily in the right upper lung field without hilar adenopathy. Before transfer to our hospital, tuberculosis chemotherapy composed of SM, INH, RFP and PZA was initiated. Over the next three weeks, fever dropped, and the above described abnormal shadows on the chest X-ray improved, leaving small cystic lesions. Although a sputum smear was negative for AFB, M. tuberculosis was isolated from cultured samples and sensitive to all standard anti-tuberculous drugs. AFB were also demonstrated on a touch imprint of biopsied cervical lymph nodes. Sputum samples turned negative one month later both on smear and culture. Moreover, high fever developed and another abnormal shadow indicative of Pneumocystis carinii (PCP) appeared in the left lung field one month after the admission. White plaque was noted in the oral cavity. Dark red nodules were observed on the upper extremities and chest wall, and diagnosed histologically as Kaposi's sarcoma. Serologic testing for HIV was positive both by PA and Western blot methods, thus AIDS was diagnosed according to the CDC surveillance case definition for AIDS with the diagnosis of tuberculosis. The patient died of wasting syndrome on the 90th hospital day. On autopsy, small thin-walled cavities were observed in the right upper lung, correlating with earlier X-ray and CT findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiological effects of SD-3212, a novel antiarrhythmic agent, on rabbit hearts in vivo and in vitro

We examined the electrophysiological effects of SD-3212, a novel antiarrhythmic agent in rabbits in in vivo and in vitro experiments. During in vivo experiments, monophasic action potentials (MAPs) of the left ventricular endocardium were simultaneously recorded with surface ECG and arterial blood pressure (BP). Under constant atrial pacing, SD-3212 (0.1, 0.2, and 0.3 mg/kg/min) was continuously infused in rabbits for 20 min. SD-3212 > or = 0.2 mg/kg/min prolonged PQ interval, QRS duration, and MAP duration, and decreased arterial BP dose dependently. During in vitro experiments, transmembrane APs were recorded from the isolated papillary muscles by a microelectrode technique. SD-3212 (3 x 10(-6)-10(-5) M) prolonged the AP duration (APD) and decreased the maximum upstroke velocity of the AP (Vmax) in a concentration-dependent manner without affecting the amplitude of AP or resting potential. The inhibitory action of SD-3212 on Vmax was enhanced as the stimulation frequency was increased, whereas the prolongation of APD did not vary with stimulation frequency. The results suggest that SD-3212 has an inhibitory action on some outward currents as well as sodium and calcium currents.

OlpB, a new outer layer protein of Clostridium thermocellum, and binding of its S-layer-like domains to components of the cell envelope

Several proteins of Clostridium thermocellum possess a C-terminal triplicated sequence related to bacterial cell surface proteins. This sequence was named the SLH domain (for S-layer homology), and it was proposed that it might serve to anchor proteins to the cell surface (A. Lupas, H. Engelhardt, J. Peters, U. Santarius, S. Volker, and W. Baumeister, J. Bacteriol. 176:1224-1233, 1994). This hypothesis was investigated by using the SLH-containing protein ORF1p from C. thermocellum as a model. Subcellular fractionation, immunoblotting, and electron microscopy of immunocytochemically labeled cells indicated that ORF1p was located on the surface of C. thermocellum. To detect C. thermocellum components interacting with the SLH domains of ORF1p, a probe was constructed by grafting these domains on the C terminus of the MalE protein of Escherichia coli. The SLH domains conferred on the chimeric protein (MalE-ORF1p-C) the ability to bind noncovalently to the peptidoglycan of C. thermocellum. In addition, 125I-labeled MalE-ORF1p-C was shown to bind to SLH-bearing proteins transferred onto nitrocellulose, and to a 26- to 28-kDa component of the cell envelope. These results agree with the hypothesis that SLH domains contribute to the binding of exocellular proteins to the cell surface of bacteria. The gene carrying ORF1 and its product, ORF1p, are renamed olpB and OlpB (for outer layer protein B), respectively.

Evolutionary origins of apoB mRNA editing: catalysis by a cytidine deaminase that has acquired a novel RNA-binding motif at its active site

The site-specific C to U editing of apolipoprotein B100 (apoB100) mRNA requires a 27 kDa protein (p27) with homology to cytidine deaminase. Here, we show that p27 is a zinc-containing deaminase, which operates catalytically like the E. coli enzyme that acts on monomeric substrate. In contrast with the bacterial enzyme that does not bind RNA, p27 interacts with its polymeric apoB mRNA substrate at AU sequences adjacent to the editing site. This interaction is necessary for editing. RNA binding is mediated through amino acid residues involved in zinc coordination, in proton shuttling, and in forming the alpha beta alpha structure that encompasses the active site. However, certain mutations that inactivate the enzyme do not affect RNA binding. Thus, RNA binding does not require a catalytically active site. The acquisition of polymeric substrate binding provides a route for the evolution of this editing enzyme from one that acts on monomeric substrates.

Multiple promoters in rat acyl-CoA synthetase gene mediate differential expression of multiple transcripts with 5'-end heterogeneity

Nucleotide sequence analysis of six independently isolated cDNAs for rat acyl-CoA synthetase (ACS) revealed three forms of ACS mRNA, designated form-A, -B, and -C mRNAs, which differ in their 5'-untranslated regions. Form-A mRNA was preferentially detected in normal and peroxisome-induced livers, whereas form-B mRNA was found in peroxisome-induced livers but not in normal livers and hearts, and form-C mRNA was preferentially found in normal hearts and peroxisome-induced livers. Analysis of two overlapping genomic clones for the rat ACS gene revealed that the three 5'-untranslated regions of the mRNAs are individually encoded by three different exons located within a 20-kilobase genomic fragment. The transcription start sites of the three forms of ACS mRNA were determined and nucleotide sequences of 5'-upstream regions of the three 5'-end exons were determined. The 5'-upstream regions were fused to the chloramphenicol acetyltransferase gene and transcription units of the three forms of ACS mRNAs were determined. These data indicate that the three forms of ACS mRNA with 5'-end heterogeneity are generated by alternative transcription from three promoters in the rat ACS gene.

Effects of diet on the lipid composition of the digestive gland-gonad complex of Biomphalaria glabrata (Gastropoda) infected with larval Echinostoma caproni (Trematoda)

This study examined the effects of a larval Echinostoma caproni infection on the neutral lipid composition of the digestive gland-gonad complex (DGG) of Biomphalaria glabrata snails fed hen's egg yolk supplemented with lettuce (Y-L) or lettuce supplemented with Tetramin (L-T). Snails were experimentally infected with the miracidial stage of this echinostome, and their DGGs containing daughter rediae were analyzed for neutral lipids five weeks post-infection by qualitative and quantitative thin-layer chromatography. Light microscopy using Oil Red O (ORO) staining and transmission electron microscopy (TEM) were used to localize neutral lipids in the rediae. The DGGs of infected snails maintained on the Y-L diet showed a significant increase in free sterols and a significant decrease in triacylglycerols compared to uninfected snails maintained on the Y-L diet. The DGGs of infected snails maintained on the L-T diet showed no significant difference in free sterols or triacylglycerols compared to uninfected snails maintained on the L-T diet. ORO staining and TEM showed the presence of lipid droplets in rediae from snails on the Y-L diet. The significant decrease in triacylglycerols in the DGGs of infected snails maintained on the Y-L diet suggests that triacylglycerols were utilized by the rediae.