Morphological and morphometric study of cercariae and adult worms of Schistosoma mansoni (SLM strain) isolated from infected mice.

In northeastern Brazil, the schistosomiasis is historically endemic and considered as a public health problem. The Schistosoma mansoni São Lourenço da Mata (SLM-PE, Brazil) strain was used in several paper already published; however, morphological and morphometric studies about this strain was never done. In this work, scanning electron microscopy (SEM) was used in morphological and morphometric analysis of cercariae and adult worms. Cercariae were obtained from Biomphalaria glabrata snails and adult worms from mice, both infected by the S. mansoni SLM strain, fixed and prepared for SEM. The results showed that cercariae of S. mansoni measures 254.9 µm of length. The bodies are covered by spines, with a ventral sucker, an oral sucker with sensory receivers, and a pair of penetration glands in the head. The area of tail and body and the distance between suckers were 3,011.77, 1,530.32, and 42.9 µm, respectively. Adult worms of S. mansoni were divided into three main regions: the anterior, medial, and posterior, besides the gynecophoral canal in males. The measure of adult worms of S. mansoni was 4 mm males and 5 mm females. The anterior region length of the male was 470 µm and of the female 271 µm. All the parameters were assayed in ten samples. The morphometric values found in the SLM strain were smaller than other S. mansoni strains described in the literature as well as other helminths. This is the first morphological and morphometric study with the SLM strain of S. mansoni being extremely important for improving control strategies and life quality of the local population.

Ultrastructural and biochemical detection of biotin and biotinylated polypeptides in Schistosoma mansoni.

Biotinylation is proposed for the identification of surface proteins in Schistosoma mansoni using the streptavidin-HRP conjugate for the detection of labeled polypeptides. However, control samples also showed several endogenous biotinylated polypeptides. In an attempt to determine the possibility of nonspecific binding between the streptavidin-HRP conjugate and polypeptides from S. mansoni, the conjugate was blocked with biotinamidecaproate-N-hydroxysuccinimide ester (BcapNHS) before biotin-streptavidin blotting. No bands were detected on the nitrocellulose sheet, demonstrating the specific recognition of biotin by the streptavidin present in the conjugate. Whole cercariae and cercarial bodies and tails showed several endogenous biotinylated polypeptides. The biotin concentration was 13 micrograms/190,000 cercariae. Adult worms presented less endogenous biotinylated polypeptides than cercariae. These results may be due to changes in the environment from aerobic to anaerobic conditions when cercarial bodies (schistosomula) are transformed into adult worms and a decrease in CO2 production may occur. Cercariae, cercarial bodies and adult male worms were examined by transmission electron microscopy employing an avidin-colloidal gold conjugate for the detection of endogenous biotin. Gold particles were distributed mainly on the muscle fibers, but dispersed granules were observed in the tegument, mitochondria and cytosol. The discovery of endogenous biotin in S. mansoni should be investigated in order to clarify the function of this vitamin in the parasite.

Ultrastructural and biochemical detection of biotin and biotinylated polypeptides in Schistosoma mansoni

Biotinylation is proposed for the identification of surface proteins in Schistosoma mansoni using the streptavidin-HRP conjugate for the detection of labeled polypeptides. However, control samples also showed several endogenous biotinylated polypeptides. In an attempt to determine the possibility of monspecific binding between the streptavidin-HRP conjugate and polypeptides from S. mansoni, the conjugate was blocked with biotinamidecaproate-N-hydroxysuccinimide ester (BcapNHS) before biotin-streptavidin blotting. No bands were detected on the nitrocellulose sheet, demonstrating the especific recognition of biotin by the streptavidin present in the conjugate. Whole cercariae and cercarial bodies and tails showed several endogenous biotinylated polypeptides. The biotin concentration was 13 mug/190,000 cercariae. Adult worms presented less endogenous biotinylated polypeptides than cercariae. These results may be due to changes in the environment from aerobic to anaerobic conditions when cercarial bodies (schistosomula) are transformed into adult worms and a decrease in CO2 production may occur. Cercariae, cercarial bodies and adult male worms were examined by transmission electron microscopy employing an avidin-colloidal gold conjugate for the detection of endogenous biotin. Gold particles were distributed mainly on the muscle fibers, but dispersed granules were observed in the tegument, mitochondria and cytosol. The discovery of endogenous biotin in S. mansoni should be investigate in order to clarify the function of this vitamin in the parasite.

Characterization and potential uses of rabbit polyclonal antibodies against human plasma lecithin-cholesterol acyltransferase.

Familial and secondary deficiency of plasma lecithin-cholesterol acyltransferase (LCAT) produce circulating lipoprotein particles with gross structural and compositional abnormalities; these have adverse effects on a variety of cellular functions. Factors affecting hepatic synthesis and secretion of this plasma enzyme are largely unknown but, potentially, some of them can be investigated with monospecific antibodies. In the present study, enzymically active LCAT was purified 40,000-fold from human plasma and then used to raise polyclonal antibodies in New Zealand White rabbits. Addition of this antiserum (1 microliter) to human plasma (25 microlitres) completely inhibited LCAT activity, although it was less effective against plasma from other species. The antibodies appeared to be monospecific to plasma LCAT. They gave a single precipitin arc by crossed immunoelectrophoresis, while immunodiffusion established that there was no cross-reactivity with several apolipoproteins or with serum albumin. Moreover, the antiserum was successfully used to detect LCAT in normal human plasma by Laurell rocket immunoelectrophoresis. By contrast, Western blotting of plasma proteins using whole LCAT antiserum was largely unsuccessful because of high background staining, although this could be substantially reduced by use of an IgG fraction. However, the whole antiserum readily immunoprecipitated LCAT secreted into the culture medium of HepG2 cells, a human hepatoblastoma cell line, pre-labelled with [35S]methionine, the [35S]-labelled LCAT appearing as a narrow 65-kDa protein band by electrophoresis and fluorography. We conclude that polyclonal antibodies may be an important tool to investigate the characteristics and underlying mechanisms of secondary LCAT deficiencies, including those associated with hepatic cirrhosis and schistosomiasis.

Characterization and potential uses of rabbit polyclonal antibodies against human plasma lecithin-cholesterol acyltransferase

Familial and secondary deficiency of plasma lecithin-cholesterol acyltransferase (LCAT) produce circulating lipoprotein particles with gross structural and compositional abnormalities; these have adverse effects on a variety of cellular functions. Factors affecting hepatic synthesis and secretion of this plasma enzyme are largely unknown but, potentially, some of them can be investigated with monospecific antibodies. In the present study, enzymically active LCAT was purified 40,000-fold from human plasma and then used to raise polyclonal antibodies in New Zealand White rabbits. Addition of this antiserum (1 mul) to human plasma (25 mul) completely inhibited LCAT activity, although it was less effective against plasma from other species. The antibodies appeared to be monospecific to plasma LCAT. They gave a single precipitin arc by crossed immunoelectrophoresis, while immunodiffusion established that there was no cross-reactivity with several apolipoproteins or with serum albumin. Moreover, the antiserum was successfully used to detect LCAT in normal human plasma by Laurell rocket immunoelectrophoresis. By contrast, Western blotting of plasma proteins using whole LCAT antiserum was largely unsuccessful because of high background staining, although this could be substantially reduced by use of an IgG fraction. However, the whole antiserum readily immunoprecipitated LCAT secreted into the culture medium of HepG2 cells, a human hepatoblastoma cell line, pre-labelled with [35S]methionine, the [(35)S]-labelled LCAT appearing as a narrow 65-kDa protein band by electrophoresis and fluorography. We conclude that polyclonal antibodies may be an important tool to investigate the characteristics and underlying mechanisms of secondary LCAT deficiencies, including those associated with hepatic cirrhosis and schistosomiasis.

Occupational exposure to neurotoxicants: preliminary survey in five industries of the Camaçari Petrochemical Complex, Brazil.

The Camaçari Petrochemical Complex (CPC) is the biggest and most important industrial complex of the northeastern region of Brazil. At present, its 54 companies employ directly and indirectly about 50,000 people. Used there as solvent and raw material, compounds such as benzene and its homologues n-hexane, haloalkanes, and some alcohols have as their prime targets the central and peripheral nervous systems. Despite widespread use of these chemicals, the workers are little aware of their toxicity, and the evaluation of exposure to them has only recently become a worrisome issue. This paper discusses the contamination of occupational environments in some industries of the CPC, as well as the neurobehavioral impairment that could be found among their workers.

Cadmium in hair of children living near a lead smelter in Brazil.

In a cross-sectional study, concentrations of cadmium in hair (CdH) were determined for 263 children aged 1-9 years, living less than 900 m from a lead smelter in Santo Amaro, Brazil. The mean CdH level was significantly higher when individuals with the following characteristics were considered: female, racial group "dark" or "medium", and children of lead workers. The mean CdH value did not vary significantly according to nutritional status or iron status or hair type. Hair Cd levels increased significantly in relation to an increase in cadmium concentration in soil. An increase of 0.024 ppm in mean CdH level was estimated for each 1 ppm increase in the cadmium concentration in soil. However, children with the habit of pica had only a slight increase in CdH levels, when compared with those without the habit. The marked variations observed in CdH levels suggest the possibility of using them as an epidemiological index in situations of intense environmental pollution.

Repeated surveillance of lead poisoning among children.

In 1980, a survey of lead poisoning was carried out among 592 children aged 1 to 9 years living within 900 m of a lead smelter in Santo Amaro, Brazil. From 1980 to 1985, the lead smelter carried out a number of major improvements aimed at reducing environmental pollution. In January, 1985, a second survey was carried out among a sample of 250 children living in this same geographical area. The geometric mean of zinc protoporphyrin (ZPP) concentration in whole blood was 1.17 (standard deviation = 1.5) mumol l-1. Blood lead concentrations (PbB) determined in a subsample of 53 children had an arithmetic mean and standard deviation of 1.77 +/- 1.00 mumol l-1, with 22 children showing PbB greater than or equal to 1.68 mumol l-1. Twenty-nine (11.6%) of the 250 children lived in houses where the lead content of the soil was greater than 10,000 ppm, and they presented higher ZPP levels than the rest of the population. Children with the habit of pica for soil had elevated ZPP levels. Comparing the results from the 1980 and 1985 surveys, slight improvements in ZPP and PbB levels were observed. However, new cases of lead poisoning are still occurring in the area. The soil is highly contaminated by lead and represents a long-lasting risk factor for child intoxication.

A study of the structure of the gene for lecithin: cholesterol acyltransferase in four unrelated individuals with familial lecithin: cholesterol acyltransferase deficiency.

1. We have used polyclonal antibodies and a complementary DNA clone for human lecithin:cholesterol acyltransferase (LCAT) to study LCAT protein and the structure of the LCAT gene, respectively, in patients with familial LCAT deficiency from Norway, Ireland, Germany and Italy. 2. The patients had low levels of non-functional LCAT protein in their serum as measured by rocket immunoelectrophoresis; its mol. wt. of approximately 68,000 was identical with that of LCAT in normal plasma, as judged by immunoblotting. 3. Enzymatic digestion of DNA samples from the patients produced LCAT gene fragments which were indistinguishable from those found in normal individuals. 4. We conclude that LCAT deficiency in these patients is not caused by a large deletion or rearrangement of the LCAT gene sequences.

The isolation and characterisation of cDNA and genomic clones for human lecithin: cholesterol acyltransferase.

The protein sequencing of tryptic peptides from purified human lecithin: cholesterol acyltransferase (LCAT) identified sufficient amino-acid sequence to construct a corresponding mixed oligonucleotide probe. This was used to screen an adult human cDNA liver library, from which incomplete cDNA clones were isolated. The DNA sequence of these clones allows the prediction of the entire amino-acid sequence of the mature LCAT enzyme. The mature protein consists of 416 amino acids and contains several marked stretches of hydrophobic residues and four potential glycosylation sites. The cDNA probe detects LCAT mRNA sequences approx. 1500 bases long in human liver, but not intestine, RNA. The cDNA probe was used to isolate LCAT genomic recombinants from a human genomic library. Southern blotting data, and restriction site mapping, suggest that there is a single human LCAT structural gene between 4.3 and 5.5 kb in size.

The structural gene for lecithin:cholesterol acyl transferase (LCAT) maps to 16q22.

We have used a cDNA clone for human lecithin:cholesterol acyl transferase (LCAT) and Southern blotting techniques to identify the human LCAT gene in DNA from a series of rodent X human somatic cell hybrids. Our results are compatible with the location of the gene on human chromosome 16, and this has been confirmed using in situ hybridization of the LCAT cDNA to human metaphase chromosomes. These results confirm the earlier studies on LCAT-deficient patients, indicating that the structural gene for LCAT is on human chromosome 16q22.