Analysis of 66 kDa toxin from Bacillus thuringiensis subsp. kurstaki reveals differential amino terminal processing of protoxin by endogenous protease(s)

The endogenous protease(s) activated crystal toxin from Bacillus thuringiensis subsp. kurstaki was purified and examined. The purified toxin was homogenous, as demonstrated by two-dimensional polyacrylamide gel electrophoresis and contained 1.38 mumoles neutral sugar and 9 nmoles sialic acid per mg protein amino terminal amino acid sequence data revealed that the toxin is a cleavage product of 132 kDa protoxin with glutamic acid-30 of the deduced amino acid sequence of the crystal protein (Schnepf, H.E., Wong, H.C. and Whiteley, H.R. (1985) J. Biol. Chem. 260: 6264-6272) at the amino terminus.

Selective down-regulation of progesterone receptor isoform B in poorly differentiated human endometrial cancer cells: implications for unopposed estrogen action

The uterine endometrium responds to unopposed estrogen stimulation with rapid cell proliferation. Progesterone protects the endometrium against the hyperplastic effects of estradiol (E2) through progesterone receptors (PRs), of which two isoforms are expressed: human (h) PRA and PRB. hPRB has a longer NH2 terminus and may function differently from hPRA. Thus, the relative expression of hPRA:hPRB is likely to be important for the action of progesterone. We hypothesized that the hPRA:hPRB ratios may be abnormal in endometrial cancer, leading to a lack of normal progesterone protection against the growth-promoting effects of E2. To test this hypothesis, well-differentiated Ishikawa endometrial cancer cells were compared to poorly differentiated Hec50 and KLE cells. Reverse transcription-PCR was chosen as a sensitive method to detect transcripts for the two forms of PR. The relative expression of PR isoforms under hormonal stimulation was determined by Western blotting. Transient transfections of hPRA and hPRB into endometrial cells allowed the evaluation of the transcriptional activity of each isoform independently on reporter gene transcription under the control of a simple progesterone response element-containing promoter. The effect of coexpressing the estrogen receptor on PR expression was also studied. Ishikawa cells (well-differentiated) express both hPRA and hPRB. Both isoforms, but predominantly hPRB, are up-regulated by E2 and not by tamoxifen or the pure antiestrogen ICI 182,780. Hec50 and KLE cells (poorly differentiated) express only hPRA. No hPRB is present in the poorly differentiated cells, and it is not induced by estrogen receptor expression and/or estrogen treatment. In all cells, hPRB expression, whether endogenous or produced as a result of transfection, acts as a stronger transcription factor than hPRA on a simple progesterone-dependent promoter. We speculate that down-regulation of hPRB may predict for poorly differentiated endometrial cancers that do not respond to progestin therapy.

Endogenous protease-activated 66-kDa toxin from Bacillus thuringiensis subsp. kurstaki active against Spodoptera littoralis

The anti-lepidopteran toxin from sporulated Bacillus thuringiensis subsp. kurstaki cells, generated by the proteolytic action of endogenous protease(s) on the protoxin, was purified and studied to identify the effect of such proteolysis on the biochemical nature of the toxin. The active toxin was purified employing anion-exchange chromatography to absolute homogeneity, as indicated by SDS-PAGE and Western blotting. Antisera to the purified toxin (66 kDa) crossreacted with the protoxin (132 kDa) confirming its origin from protoxin. The purified toxin with a pI of 7.95 was derived from the N-terminal region of the protoxin (pI 7.6). Circular dichroism data revealed that the toxin has significant secondary structure and it undergoes pH dependent conformational change. Unlike the toxin generated by exogenous proteases such as trypsin, etc., the endogenous protease(s) activated toxin is highly lethal to a tolerant insect variety of the lepidopteran order, Spodoptera littoralis.

Involvement of an endogenous metalloprotease in the activation of protoxin in Bacillus thuringiensis subsp. kurstaki

Insecticidal crystal proteins harvested from sporulated cultures of Bacillus thuringiensis subsp. kurstaki contain the protoxin (Mr 132 kDa) and minor amounts of toxin (66 kDa). The proteolytic processing of 132 kDa protoxin to an active 66 kDa toxin is brought about by exogenous proteases or larval gut enzymes. Under denaturing/reducing conditions this conversion is also mediated by endogenous protease(s) of the producer organism. This endogenous protease is identified as a metalloprotease as the activation process is inhibited by ethylenediamine tetraacetic acid at 2 mM concentration.

Determinants of triacylglycerol transport from the endoplasmic reticulum to the Golgi in intestine

The ability of the intestinal cell to export triacylglycerol (TG) is a physiologically regulatable function. The intracellular site where this occurs is unknown, although available evidence suggests that the step between the endoplasmic reticulum (ER) and the Golgi is the most likely. We studied this process in rat enterocytes that were isolated from the proximal intestine. A novel system was developed in which [3H]TG was transported from ER to the Golgi. This process was time, ATP, temperature, and cytosol dependent. The cytosolic factor(s) was heat and trypsin sensitive. TG transport was directly proportional to the amount of added nonradiolabeled acceptor Golgi. The rate of TG transported to the Golgi was the fastest in cells isolated from rats that had been intraduodenally infused in vivo with glyceryltrioleate (TO) plus phosphatidylcholine and slowest in cells isolated from bile-fistulated rats infused with TO in vivo compared with cells from in vivo TO-infused, bile duct intact rats, mimicking the relative transport rates seen in vivo. TG transport in vitro could not be quenched by adding TG emulsions, chylomicrons, liposomes, or guanosine 5'-O-(3-thiotriphosphate). Cytosol from the liver and kidney supported TG transport, but the Golgi from liver or kidney did not accept TG from intestinal ER. We conclude that an intestinally specific, active transport mechanism transports TG from the ER to the Golgi and that this might be a regulatory step in TG export from the intestinal cell.

Selective cleavage of welan gum (S-130) by oxidative decarboxylation with lead tetraacetate

Oxidative decarboxylation of peracetylated welan gum (S-130) with lead tetraacetate resulted in selective cleavage of the glucuronosidic linkages. Products of the degradation were reduced with sodium borohydride, O-deacetylated, and fractionated. Polymeric and oligomeric fractions were separated and analysed by 1H NMR spectroscopy and fast atom bombardment mass spectrometry, and were found to be monomers, dimers, and trimers of the repeating unit. Results show that this method may be used to liberate alditol-terminated multiples of the repeating unit of peracetylated glycuronans by cleavage and degradation of the uronic acid residues. The reaction sequence also confirms the recent finding that welan gum contains repeating units with randomly distributed terminal groups.

Distribution of placental alkaline phosphatase (PLAP) gene frequencies in Andhra Pradesh (south India)

The data available on the distribution of variants, phenotype and gene frequencies of different placental isoenzymes, especially for caste populations of Andhra Pradesh, are very scanty. In the present study, phenotype and gene frequency distributions of placental alkaline phosphatase (PLAP) of two caste groups namely, Lambada and Perika of Andhra Pradesh, South India, are reported. All the common phenotypes and the single case of a rare phenotype have been observed in the Lambada group.

Caste variation of two placental phosphatases

Three-hundred and thirty placental samples from two caste populations of Andhra Pradesh, South India, were screened by electrophoresis for the variants of acid phosphatase and for the phenotypes of alkaline phosphatase. Only the six common phenotypes of alkaline phosphatase were detected; no variants of acid phosphatase were found.

Late phase response during nasal challenge: effect of astemizole on leukotriene B4 levels

Nasal provocation (NP) in allergic rhinitis patients can elicit a late phase inflammatory response in which interleukins (IL), leukotrienes (LT), and neutrophils have been implicated. Certain antihistamines have been shown to have anti-inflammatory properties. The objective was to determine whether astemizole at 10 mgs/day has any anti-inflammatory characteristics. We clinically evaluated 20 patients with allergic rhinitis and measured nasal IL-8 and LTB4 during NP with increasing doses of grass and ragweed antigen in a double-blind placebo-controlled fashion after a 4-week course of treatment. Clinical symptom scores for sneezing, pruritus, and rhinorrhea were evaluated. Nasal fluid was examined by ELISA and RIA for IL-8 and LTB4 levels along with neutrophil assessment before NP and at 3, 6, and 8 hours. Symptom scores for nasal sneezing, pruritus, rhinorrhea, and nasal LTB4 levels at 6 and 8 hours and IL-8 at 3, 6, and 8 hours were generally lower in astemizole-treated patients compared to those on placebo. Nasal IL-8 levels corresponded to LTB4 levels at diluent and at 6 hours in the placebo group (P = 0.01). The percentage of neutrophils correlated with LTB4 levels at baseline, coefficient = 0.76, P = 0.02 and at 6 hours, coefficient = 0.62, P = 0.035 in the placebo group. This study is the first to demonstrate an effect of astemizole during NP on IL-8 and LTB4 levels with a significant correlation of neutrophil numbers in untreated patients during the nasal late phase response.

An affinity method for the purification of mannose 6-phosphate receptor proteins (MPR 215) from rat tissues and goat liver

An affinity matrix (Sepharose 6B-divinyl sulfone-pentaphosphomannan) has been developed which can be efficiently used for the purification of the MPR 215 from different tissues of rat as well as from goat liver. The matrix developed is relatively easy to prepare compared with the available procedures, and can be used for the purification of similar receptor proteins from other sources.

Anthropometric indices, cord length and placental weight in newborns

A study on the anthropometric indices of 3835 singleton newborn babies was conducted over a four months period at Sree Avittom Thirunal Hospital, Trivandrum. Of these, 1921 (50.1%) were male babies and 1914 (49.9%) were female babies. The majority of infants (43%) were born to the middle socio-economic groups and the mean birth weight of babies was high among the high-income groups. Five hundred and ninety six (15.5%) babies weighed less than 2500 g; of these 121 (20.2%) were preterm and 477 (79.8%) were full term. The prevalence of low birth weight (LBW) was high (22.0%) among the mothers aged between 15 and 19 years. There was a significant difference (p < 0.001) in the mean birth weight (BW) of term male and female babies but there was no significant differences in their body length, head circumference and cord length. The mean ponderal index of term newborn babies was 2.3 g/cm3. The mean placental weight of LBW term and preterm babies was less than that of the corresponding normal weight babies. The birth weight of babies was directly proportional to their placental weight.

A study on the health status of twin babies

A study on twin births was conducted from May 1993 to April 1994 at S.A.T. Hospital, Thiruvananthapuram. The twinning rate in this period was found as 17.33 per 1000 births. 79.6% babies in the twin pairs were of like sex and 20.4% were of unlike sex. The incidence of low birth weight twin babies in this study was 68.9%. There was no significant difference in the physical parameters (birth weight, body length and head circumference) of twin babies in relation to sex. The incidence of twin birth was higher among primipara mothers and in the mothers of age group 21 to 25 years. The first born baby (twin A) was found to be heavier than the second born baby (twin B) in 44.78% twin pairs and their mean birth weight difference was 438 g, while the second born baby (twin B) was found to be heavier than the first born (twin A) in 38.31% twin pairs and their mean birth weight difference was 291 g. Statistical analysis showed that the difference between the mean birth weight difference in the case of twin A > B was significantly greater when compared to that of twin A < B.

Distribution of placental alkaline phosphatase gene (PLAP) frequencies in two groups of Muslim populations of Andhra Pradesh

The present paper gives the results of our study on the distribution of phenotypes and gene frequencies of placental alkaline phosphatase (PLAP) in the Shia and Khoja Muslim groups living in Hyderabad, Andhra Pradesh, South India. All six common PLAP phenotypes and three cases of rare phenotypes have been observed.

Dietary carbohydrates and synthesis and secretion of apolipoprotein B-containing lipoproteins in rat hepatocytes

The influence of glucose-, sucrose- and starch-containing diets on the synthesis and secretion of lipoprotein in the density range of very-low-density lipoproteins (VLDLs) and low-density lipoproteins (LDLs) was studied via primary cultures of rat hepatocytes. Apolipoprotein B secreted by hepatocytes from rats fed a sucrose diet was significantly more than in rats fed starch or glucose. This was further confirmed by pulse labeling with [3H]leucine and chase study. Increased synthesis and secretion of cholesterol in lipoproteins of the VLDL and LDL density range and decreased synthesis and secretion of triglyceride in the VLDL fraction were observed in hepatocytes from sucrose-fed animals compared with those fed glucose. This indicates that the VLDL secreted by hepatocytes from sucrose-fed animals was richer in cholesterol but poorer in triglycerides than from glucose/starch- and glucose-fed animals. These findings also suggest an increase in the synthesis and secretion of apolipoprotein B by hepatocytes on sucrose feeding, indicating an association with an increase in cholesterogenesis.

Synthesis and secretion of lipoproteins by primary cultures of rat hepatocytes

Synthesis and secretion of VLDL and LDL by primary cultures of rat hepatocytes maintained in serum free medium have been studied. A time-dependent increase found in the [3H]leucine labelled lipoproteins which floated at a density of 1.006 g/ml indicate the secretion of VLDL into the medium. That the hepatocytes also secrete. LDL is shown by floatation of [3H]leucine labelled lipoproteins by sequential centrifugation at a density range of 1.006-1.06 g/ml. Electrophoretic and immunoprecipitation analysis show that about 60% and 65% respectively of 3H-radioactivity is associated with apoB in the two fraction of lipoproteins. At about 12hr 70-75% lipoproteins in the culture medium is in the VLDL density range and 25-30% is in the LDL density range. Conversion of secreted VLDL to LDL has also been shown by incubating hepatocytes with pre-labelled lipoproteins when there is a decrease in the fraction of VLDL range with a corresponding increase in the fraction of the LDL density range. Addition of glycosaminoglycans such as hyaluronic acid, chondroitin sulphate, and heparin into the medium cause significant increase in the synthesis and secretion of [3H]apoB into the medium indicating a possible secretory control of apoB by local reuptake.

Synthesis and secretion of apo B containing lipoproteins by primary cultures of hepatocytes isolated from rats fed atherogenic diet

The effect of experimentally induced atherosclerosis on the synthesis and secretion of lipoproteins in the density range of very low density lipoproteins (VLDL) and low density lipoproteins (LDL) have been studied using primary cultures of rat hepatocytes. Rats fed atherogenic diet showed higher levels of lipids associated with serum VLDL and LDL fraction, aorta and liver when compared with animals fed normal diet. Incorporation of [3H]leucine into apo B associated with the cell layer and secreted by hepatocytes from rats fed atherogenic diet was significantly more when compared with normal hepatocytes. [14C]Acetate incorporation studies showed that the synthesis of cholesterol was lower in hepatocytes from atherogenic diet fed rats, but more of the newly synthesised cholesterol was found in the secreted VLDL; secretion of lipids, particularly triglycerides, unesterified cholesterol and cholesterol in the lipoproteins in the density range of VLDL and LDL was significantly more in these hepatocytes. The relative distribution of [3H]-radioactivity in the LDL density range was 57% in hepatocytes from atherogenic diet fed animals as compared with 28% in controls, suggesting a relatively higher production of lipoproteins in the LDL density range than VLDL by these cells. These results indicate that the hypercholesterolemia in atherogenic diet fed animals may among other factors be caused by increased synthesis of apo B by liver cells and resultant increase in the secretion of apo B containing lipoproteins.

Synthesis and secretion of VLDL by rat hepatocytes--modulation by cholesterol and phospholipids

The synthesis and secretion of apoB, the major protein component of very low density lipoprotein (VLDL) and low density lipoprotein (LDL), were studied using rat hepatocytes maintained in primary culture. Supplementation of hepatocytes with rat serum VLDL and LDL increased the production of apoB while delipidated lipoproteins had no significant effect, suggesting a role for lipids in the production of apoB. Addition of cholesterol to the culture medium also increased the production of apoB in a concentration-dependent manner. Pulse labelling followed by chase in presence of cholesterol indicated enhancement in apoB secretion. Mevinolin which inhibits cholesterol synthesis significantly reduced the secretion of apoB. The presence of phosphatidylcholine and phosphatidylethanolamine in the culture medium also increased the secretion of apoB into the medium. These data suggest that availability of lipids, particularly cholesterol, is an important determinant of apoB synthesis and secretion as VLDL.

In vivo biocompatibility of an aliphatic crosslinked polyurethane in rabbit

A cage implantation technique has been adopted in a rabbit animal model to investigate the biocompatibility of an aliphatic crosslinked polyurethane based on hexamethylene diisocyanate (HDI). In this study, four cages are represented; the cage containing the candidate polyurethane material, biomedical grade polyurethane (Tecoflex), the commercial grade polyvinylchloride (PVC), and an empty cage which were implanted subcutaneously in rabbits. Exudates were aspirated from these cages at 4, 7, 14, and 21 days postimplantation. Exudates were analyzed for variations in proteins, cell counts, and extracellular enzymes. Results with the four types of cage implants showed that the candidate polyurethane caused an inflammatory response comparable to that caused by medical-grade Tecoflex and the empty cage control.

Management of menopause when estrogen cannot be used

Estrogen deficiency, whether surgically induced or as a consequence of natural ovarian failure, has destructive effects on many organ systems. With current levels of life expectancy, untreated women may expect to spend a third of their lifetime in this state. Appropriate estrogen replacement therapy (ERT) can avert (if started promptly) or ameliorate these devastating consequences, some of which (osteoporotic fractures, increased cardiovascular morbidity) can be lethal. Nevertheless, from 10 to 20% of postmenopausal women may have significant contraindications to ERT. Treatment of symptoms and improving the quality of life is imperative, yet many physicians abjure intervention, for reasons which are not entirely clear. Recent studies of conventional intervention with sedatives or tranquilisers show results equivalent to placebo therapy. On the other hand, specific agents with demonstrated effectiveness are available for management of the major estrogen-deficiency effects, although none of them are truly adequate replacement for the effect of estrogen itself.

Structural studies of an arabinoxylan isolated from Litsea glutinosa (Lauraceae)

A water-soluble arabinoxylan (D-xylose and L-arabinose in the molar ratio 1.0:3.4) was isolated from the mucilaginous bark of Litsea glutinosa (Lauraceae). The results of methylation analysis, partial hydrolysis, and 1H- and 13C-n.m.r. spectroscopy indicated a backbone of (1----4)-linked beta-D-xylopranosyl residues substituted at both positions 2 and 3 with side chains composed of either single or (1----3)-linked arabinofuranosyl residues. Both alpha-L- and beta-L-arabinofuranosyl residues were present. It is possible that side chains composed of two beta-L-arabinofuranosyl residues are attached mainly at O-2 of some xylosyl residues.

Effect of breast feeding on the development of anti-idiotype antibody response to F glycoprotein of respiratory syncytial virus in infant mice after post-partum maternal immunization

Groups of lactating BALB/c mice were immunized in the immediate postpartum period with high doses of mAb (Ab-1) to the F-glycoprotein (F-gp) of respiratory syncytial virus (RSV). This antibody possessed neutralizing activity against the whole virus. The immune response to F-gp was studied in the breast feeding infant mice of such mothers at regular intervals before and after weaning. All infant mice exhibited anti-F-gp activity in serum, which was detected until 6 wk of age. Splenic cells of such breast feeding infant mice collected after weaning exhibited in vitro synthesis of antibody against Ab-1, the antibody previously used for maternal immunization. Subsequent immunization with homologous purified RSV F-gp resulted in a booster response for IgG, IgM, and plaque-neutralizing antibody to the immunizing RSV protein and to the whole virus in the infants primed via breast feeding. The enhanced antibody response was specific for the antigenic epitopes of the virus protein recognized by the monoclonal antibody used for maternal immunization. Similar booster effect was seen in control infants of nonimmunized mothers who were immunized with a polyclonal Ab-2 prepared by repeated immunization with Ab-1 in DBA/2 mice. These data demonstrate induction of RSV-specific anti-idiotype antibody in the neonates via the process of breast feeding, secondary to maternal immunization after the delivery of the neonate. Use of idiotypic vaccines in the mother and the transfer of RSV-specific idiotypes may offer an alternate approach to the development of effective immunoprophylaxis for RSV infection in early infancy.

Effect of breast feeding on the development of anti-idiotype antibody response to F glycoprotein of respiratory syncytial virus in infant mice after post-partum maternal immunization

Groups of lactating BALB/c mice were immunized in the immediate postpartum period with high doses of mAb (Ab-1) to the F-glycoprotein (F-gp) of respiratory syncytial virus (RSV). This antibody possessed neutralizing activity against the whole virus. The immune response to F-gp was studied in the breast feeding infant mice of such mothers at regular intervals before and after weaning. All infant mice exhibited anti-F-gp activity in serum, which was detected until 6 wk of age. Splenic cells of such breast feeding infant mice collected after weaning exhibited in vitro synthesis of antibody against Ab-1, the antibody previously used for maternal immunization. Subsequent immunization with homologous purified RSV F-gp resulted in a booster response for IgG, IgM, and plaque-neutralizing antibody to the immunizing RSV protein and to the whole virus in the infants primed via breast feeding. The enhanced antibody response was specific for the antigenic epitopes of the virus protein recognized by the monoclonal antibody used for maternal immunization. Similar booster effect was seen in control infants of nonimmunized mothers who were immunized with a polyclonal Ab-2 prepared by repeated immunization with Ab-1 in DBA/2 mice. These data demonstrate induction of RSV-specific anti-idiotype antibody in the neonates via the process of breast feeding, secondary to maternal immunization after the delivery of the neonate. Use of idiotypic vaccines in the mother and the transfer of RSV-specific idiotypes may offer an alternate approach to the development of effective immunoprophylaxis for RSV infection in early infancy.

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 18A

The structure of the capsular polysaccharide (S18A) elaborated by Streptococcus pneumoniae type 18A has been investigated by using methylation analysis and n.m.r. spectroscopy. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure. (formula; see text) In this structure, the absolute configuration of the glycerol 1-phosphate moiety has not been determined but is assumed to be D from biosynthesis considerations. The structure of S18A is, as expected, closely similar to those determined for S18F and S18C.

Structural studies of a polysaccharide (S-88) elaborated by Pseudomonas ATCC 31554

The structure of the extracellular polysaccharide elaborated by Pseudomonas ATCC 31554 has been investigated, methylation analyses, specific degradations, and 1H-n.m.r. spectroscopy being the main methods used. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units with the structure: ----3)-beta-D-Glcp-(1----4)-beta-D-GlcpA-(1----4)-beta-D-Glcp- (1----4)-alpha-L-[Rha or Man]-(1---- 3 increases 1 alpha-L-Rha. An unusual feature is that a sugar residue in the chain may be either L-rhamnose or L-mannose. The polysaccharide also contains O-acetyl groups (approximately 5%) which have not been located.