Outer membrane proteins of Aeromonas hydrophila induce protective immunity in goldfish.
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Biomedical subjects
Publications and source records attributed to M H Rahman.
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Microsatellite DNA markers from 13 simple sequence repeat (SSR) loci were used to compare genetic diversity between preharvest pristine and postharvest residual gene pools of two adjacent virgin, old-growth ( approximately 250 years) stands of eastern white pine (Pinus strobus L.) in Ontario. There was concurrence in genetic diversity changes in the postharvest gene pools of the two stands. The total and mean numbers of alleles detected in each stand were reduced by approximately 26% after tree density reductions of approximately 75%. Approximately 18 and 21% of the low-frequency (0. 25 > P > or = 0.01) alleles and 76 and 92% of the rare (P < 0.01) alleles were lost from residual stands A and B, respectively, after harvesting. Multilocus gametic diversity was reduced by 38 and 85% and genotype additivity by approximately 50% in the residual stands after harvesting. Latent genetic potential of each stand was reduced by approximately 40%. Although heterozygosity was reduced (1-5%) in the postharvest residual stands, the reductions were not substantial and not comparable to those using other genetic diversity measures. The reductions in genetic diversity measures were slightly higher than those theoretically expected in postbottleneck populations according to drift theory. In the absence of substantial gene migration that could ameliorate the genetic losses, the ability of the postharvest white pine gene pools to adapt to changing environmental and disease conditions may have been compromised. The microsatellite DNA results for genetic effects of harvesting in old-growth eastern white pine stands were similar to those that we reported earlier from allozyme analysis (Buchert et al. 1997). The results indicate that silvicultural practices should ensure that the gene pools of remaining pristine old-growth stands are reconstituted in the regenerating stands.
The investigations on protein quality of raw faba bean seed meal (Vicia faba L. minor) and its fractions were carried out using rats in two experiments. Two varieties of faba seeds were used, locally grown faba bean 'Kalimattar' or 'black' (KSM) (492 g/kg diet) and its exotic counterpart Vicia faba L. minor 'White' (VFW) obtained from International Centre for Agricultural Research in the Dry Areas (ICARDA) (540 g/kg diet). The pulverized cotyledons of 'Kalimattar' (KMC; 438 g/kg diet), hull (KMH; 78 g/kg diet) as well as cotyledons of 'White' faba bean (VFWC; 470 g/kg diet) and hull (VFWH; 82 g/kg diet) fractions were tested. All diets were made isocaloric and isonitrogenous, however, without addition of individual amino acids to the target requirements. Performance of rats fed on both locally grown KSM and exotic FBW meal-fed rats were found to be inferior to those obtained from the rats fed on standard protein diet. The net protein utilization (NPU) of the rats fed on this seed meal was comparatively better than those obtained from the VFW. Replacement of standard protein with cotyledons from the either of the seed (KMC and VFWC) depressed food intake and protein utilization. This was due, in part, to the excretion of comparatively higher amount of nitrogen in faeces. Inclusion of KMH in the diet had no adverse effects on any variable studies as compared to the VFWH, which was found to impose severe restriction on the absorption of standard protein added to this diet. As a result, body weight gain, and NPU value were significantly lower than those obtained from the KMH. We conclude that the locally grown faba bean 'Kalimattar' is better than those of exotic 'White' cultivar and may contain less antinutritional substances. However, this warrants further investigations.
Microsatellite loci or simple sequence repeat loci (SSRs) were isolated in alpine larch (Larix lyallii Parl.) and western larch (Larix occidentalis Nutt.). In total, 14 SSR loci were characterized; two [(TCT)4, A7] came from published Larix DNA sequence data, one (CA)17 was obtained from a partial non-enriched alpine larch total genomic DNA library, and the remaining 11 loci were obtained from larch genomic DNAs enriched for (CA)n repeats. The SSR regions in these clones could be divided into three categories: perfect repeat sequences without interruption, imperfect repeat sequences with interruption(s), and compound repeat sequences with adjacent tandem simple dinucleotides. Eight of the 14 loci analyzed were found to be polymorphic and useful markers after silver-staining polyacrylamide gel electrophoresis. In addition, several SSR primers developed for alpine larch were able to successfully amplify polymorphic loci in its related species, western larch, and among other closely related taxa within the Larix genus. The inheritance of microsatellite loci was verified by analysis of haploid megagametophyte and diploid embryo tissues of progeny obtained from controlled crosses between western larch and alpine larch. All microsatellite loci analyzed had alleles that segregated according to expected Mendelian frequencies. Two species-specific markers (UAKLly10a and UAKLla1) allow easy and rapid identification of specific genetic entry of alpine larch and western larch at any stage in the sporophyte phase of the life cycle. Therefore, these markers are efficient in identifying the parental species and to validate controlled crosses between these two closely related species. These results are important in tree improvement programs of alpine larch and western larch aimed at producing genetically improved hybrid stock for reforestation in Western Canada and U.S.A.
Markers for eight new microsatellite DNA or simple sequence repeat (SSR) loci were developed and characterized in trembling aspen (Populus tremuloides) from a partial genomic library. Informativeness of these microsatellite DNA markers was examined by determining polymorphisms in 38 P. tremuloides individuals. Inheritance of selected markers was tested in progenies of controlled crosses. Six characterized SSR loci were of dinucleotide repeats (two perfect and four imperfect), and one each of trinucleotide and tetranucleotide repeats. The monomorphic SSR locus (PTR15) was of a compound imperfect dinucleotide repeat. The primers of one highly polymorphic SSR locus (PTR7) amplified two loci, and alleles could not be assigned to a specific locus. At the other six polymorphic loci, 25 alleles were detected in 38 P. tremuloides individuals; the number of alleles ranged from 2 to 7, with an average of 4.2 alleles per locus, and the observed heterozygosity ranged from 0.05 to 0.61, with an average of 0.36 per locus. The two perfect dinucleotide and one trinucleotide microsatellite DNA loci were the most informative. Microsatellite DNA variants of four SSR loci characterized previously followed a single-locus Mendelian inheritance pattern, whereas those of PTR7 from the present study showed a two-locus Mendelian inheritance pattern in controlled crosses. The microsatellite DNA markers developed and reported here could be used for assisting various genetic, breeding, biotechnology, genome mapping, conservation, and sustainable forest management programs in poplars.
BACKGROUND AND AIMS: Previous work in our laboratory has shown that chylomicron triacylglycerol is lipolysed in vitro by lipoprotein lipase more rapidly when the particles are enriched with n-6 polyunsaturated as compared to saturated, monounsaturated or n-3 polyunsaturated fatty acids. It is possible, however, that this does not reflect the situation in vivo, where the active enzyme is bound to the vascular endothelium. The aim of the present study is to investigate the effect of the fatty acid composition of chylomicrons on their lipolysis in the rat in vivo. METHODS AND RESULTS: [3H]Oleate-labelled chylomicrons derived from palm, olive, corn or fish oil (enriched in saturated, monounsaturated, n-6 polyunsaturated and n-3 polyunsaturated fatty acids respectively) containing > 90% of the label in triacylglycerol were injected intravenously into functionally hepatectomised rats and blood samples were taken at time intervals up to 40 min. The radioactivity in serum triacylglycerol decreased significantly more rapidly when corn oil as compared to palm, olive or fish oil chylomicrons were used. Conversely, the radioactivity in serum free fatty acid derived from corn oil chylomicrons showed a faster increase than that derived from the other three types of particles. CONCLUSIONS: These results indicate that chylomicrons enriched with n-6 polyunsaturated fatty acids are converted to chylomicron remnants in vivo more rapidly than those enriched with saturated, monounsaturated or n-3 polyunsaturated fatty acids. This provides a partial explanation for the differential rate of removal from the blood of cholesterol carried in chylomicrons of different fatty acid composition demonstrated in previous work from this laboratory.
Early intervention with slow acting anti-rheumatic drugs (SAARDs) has led to improvement in substantial proportion of rheumatoid arthritis (RA) patients. The present open, controlled study was designed to assess whether a combination of SAARDs offer any added benefit. Fifty-four adult RA patients were randomly allocated to methotrexate (MTX) (n = 27) and MTX plus sulphasalazine (SSZ) (n = 27) groups. The subjects were followed-up fortnightly for four weeks then monthly for six months. The disease activity was assessed with the help of 10 clinical and four laboratory indices. The improvement was graded as: minor, mild decreases in indices, non-steroidal anti-inflammatory drugs (NSAIDs) continued, physician's global assessment (PGA) decreased by one; marked, acceptable decreases in indices, NSAIDs being taken sparingly, PGA decreased by at least 2, and complete, all indices normalised and patients discontinued NSAIDs completely. The improvement was considered clinically important when marked or complete improvement occurred. Adverse drug reactions resulted in withdrawal of 4 subjects from the MTX + SSZ group and 1 from the control groups. Four and three subjects in the combined and MTX groups respectively were lost to follow-up. Subjects in both groups showed significant decline in all indices except hemoglobin and neutrophil count. The differences between the two groups in the pre-treatment and post-treatment values were insignificant. Complete, marked, minor and no improvement occurred in 4 (21%), 12 (63%), 3 (16%) & 0 in the MTX and in 11 (48%), 7 (30%), 4 (17%) & 1 (4%) in MTX + SSZ groups respectively. The differences in the rates of complete and clinically important improvement between the two groups were insignificant (P 0.1398 and 0.7092). The incidence of side effects was insignificantly higher in the MTX + SSZ group. Most of them were mild and transient. The combination of SAARDs offered little added advantage in RA. However, the higher rate of complete improvement in the combination group justifies trials including larger samples.
Poly[2'-O-(2,4-dinitrophenyl)]poly(A)[DNP-poly(A)] has been found to be a potent inhibitor in solution for RNases A, B, S, T1, T2 and H as well as phosphodiesterases I and II. Kinetic measurements with RNase B and RNase T1 showed DNP-poly(A) to be a reversible competitive inhibitor with K1 equal to 1.03 and 1.05 microM, respectively. Data on the quenching of fluorescence of RNase T1 by DNP-poly(A) indicate the existence of more than one RNase-binding site in each DNP-poly(A) molecule. By attaching each DNP-poly(A) molecule at one end covalently to oxirane acrylic beads, an affinity column was prepared for selective removal of RNases from aqueous solutions by simple filtration. It was found that a 1000-fold reduction in RNase concentration can be obtained by passing either 7.0 microM or 7.0 nM RNase A solution through a 5-cm-long column. The column can be saturated by passing through a concentrated RNase solution and subsequently regenerated by washing with salt solution. The regenerated column can be used repeatedly with no significant decrease in RNase-binding affinity and capacity. By titration of the derivatized beads with RNase, the first dissociation constant (Kd) and binding capacity for the bound enzyme can be determined. The (Kd) was found to be 0.66 microM for RNase B and 0.48 microM for RNase T1; the corresponding binding capacities were found to be 21.0 x (10)-8 and 9.6 x (10)-8 mol/g, respectively.
The interaction of a series of benzothiadiazides with human serum albumin (HSA) was investigated by equilibrium dialysis (ED) and spectroscopic methods including circular dichroism (CD). The primary binding site of benzothiadiazides was designated site II, the diazepam site on the HSA molecule, as indicated by displacement experiments using different site-selective probes. Tyrosine and lysine amino acid residues were probably involved in the binding site of these compounds to HSA. Both electrostatic and hydrophobic interactions were found to play a role in the binding of these compounds to HSA. Among the compounds tested, chlorothiazide had the highest affinity (K1 = 5.5 x 10(4) M-1, K2 = 5.8 x 10(3) M-1). The primary binding affinity of the compounds for HSA was of the order: chlorothiazide > cyclopenthiazide > polythiazide > ethiazide > trichlormethiazide = methyclothiazde > hydrochlorothiazide. Binding was insensitive to the N-B transition of HSA. The binding site is proposed to consist of a cationic site on the surface of the HSA molecular with a hydrophobic crevice to accommodate the aromatic ring of the compounds. Positions 3 and 7 of the benzothiadiazide molecule is thought to affect the binding affinity to HSA.
The binding of carprofen, a non-steroidal anti-inflammatory drug of the aryl propionic acid class [2-(6-chlorocarbazole)propionic acid], and its enantiomers to human serum albumin (HSA) has been studied by dialysis and spectroscopic methods. Binding parameters obtained by different methods were in close agreement. The binding of carprofen to HSA by both fluorescence and equilibrium dialysis (ED) methods is characterized by two sets of association constants [K1 = 5.1 x 10(6) M-1 (fluorescence) and 3.7 x 10(6) M-1 (ED), K2 = 3.7 x 10(5) M-1 (fluorescence) and 1.3 x 10(5) M-1 (ED)]. The S(+)-enantiomer of carprofen showed slightly higher affinity for HSA than its corresponding antipode by both methods. Different analyses of the binding to HSA suggested the presence of one high affinity site and five to seven low affinity sites for carprofen and its enantiomers on HSA. Fluorescence displacement data implied that carprofen primarily binds to site II, the benzodiazepine site, while the low affinity site of carprofen is site I, the warfarin site. Circular dichroism data suggested different mechanisms for the high affinity and the low affinity binding of carprofen to HSA. The data are consistent with the major part of the binding energy at site II being electrostatic and hydrophobic interactions, whereas for the low affinity binding, hydrophobic interactions. Binding was exothermic, entropy driven and spontaneous, as indicated by the thermodynamic analyses. From binding data with chemically modified HSA derivatives, it is likely that tyrosine, lysine and histidine residues are especially involved in carprofen binding to HSA, and it is most likely that the high affinity binding of carprofen is located in the N-terminal part of domain III or that section of protein plus the C-terminal part of domain II of the HSA molecule. When the binding of carprofen to HSA was compared to the binding of carprofen methyl ester to HSA (K = 0.1 x 10(6) M-1), the carboxyl group of carprofen was found to play an important role especially in the high affinity binding of carprofen to HSA. The high affinity of carprofen to HSA was independent of the conformational changes on HSA caused by N-B transition.
The site-to-site displacement of carprofen, a site II-specific drug, bound to human serum albumin (HSA) by ibuprofen, another site II-specific drug, was qualitatively and quantitatively studied by circular dichroism (CD) and equilibrium dialysis (ED). Carprofen gives rise to different CD spectra at lower (1:1) and higher (3:1) molar ratios to HSA, indicating different mechanisms for the binding of this drug to its high and low affinity sites on HSA. Ibuprofen at a 5:1 molar ratio to HSA displaces carprofen at a molar ratio of 1:1 to HSA from its high affinity binding site (site II) to its low affinity site (site I), as shown by production of the CD spectrum similar to that obtained in the case of the carprofen-HSA complex at a molar ratio 3:1. As revealed by the ED experiments, the free fraction of carprofen at a molar ratio of 1:2 to HSA (2 x 10(-5) M) was not initially increased by the addition of ibuprofen at a lower concentration, but at a higher concentration (6 x 10(-5) M), the free fraction was increased by only 90%. When site I was sufficiently blocked by a site I-specific drug like warfarin or phenylbutazone (6 x 10(-5) M), there was about a 4-fold increase in the free fraction of carprofen caused by ibuprofen. This site-to-site displacement demonstrated by carprofen was found to be stereospecific as indicated by the highest interaction between the S(+)-enantiomers of carprofen and ibuprofen. Moreover, the displacement of carprofen occurred at the azapropazone region rather than the warfarin region of site I on HSA.
A site-oriented study of nine non-steroidal anti-inflammatory drugs (NSAIDs), suprofen, ibuprofen, diclofenac sodium, pirprofen, flurbiprofen, ketoprofen, phenylbutazone, oxyphenbutazone, and ketophenylbutazone, on human serum albumin (HSA) was carried out at pH 7.4 by various direct and indirect methods to gain insight into the high affinity binding sites of NSAIDs. The binding was determined by equilibrium dialysis, circular dichroism and fluorescence methods in order to strengthen the results. Irrespective of the method used, close agreement between the binding parameters obtained by the different methods was obtained. A site-oriented description, as revealed by the fluorescent probe displacement method, suggests that site II and site I probes bound to HSA were selectively displaced by NSAIDs with a carboxyl group and without a carboxyl group, respectively. The absence of a carboxyl group of the NSAIDs changed the binding site from site II to site I. Different binding models describing the competitive and independent binding of a NSAID and a site-specific probe bound simultaneously to HSA further describe the respective high affinity binding sites for NSAIDs, thus underscoring the necessity of a carboxyl group in order for a NSAID to bind to site II. The presence of tyrosine, lysine and histidine amino acid residues in the binding of carboxyl group-containing NSAIDs to HSA was evident, whereas tryptophan is believed to take part in the binding of non-carboxyl group-containing NSAIDs. The present findings support the proposal that two separate primary binding sites exist for different NSAIDs; hence, an attempt to correlate the present results with those in literature has been made.
The interaction of dicumarol and its seven other derivatives with human serum albumin (HSA), alpha 1-acid glycoprotein (AGP) and desialylatedAGP (asialoAGP) has been investigated by circular dichroism (CD) and fluorescence. The binding parameters of dicumarol and its derivatives obtained from fluorescence almost agreed with those obtained from CD. The binding data indicated that the total binding affinities (nK) to HSA were higher than the binding affinities to AGP and asialoAGP. Hydrophobic interaction was the driving force for the binding to all the three proteins and nK values in the binding process were found to be increased with the increase of hydrophobicity of the compound. This was evidenced by the attempts taken to correlate binding affinities with partition coefficients. Both electrostatic and van der Waals interactions were not found to play any significant role in the binding of these compounds to any of these three proteins. However, in case of the AGP and asialoAGP binding, apart from the hydrophobic interaction, some other forces may be involved as evidenced from the experimental data. Binding was exothermic, entropy driven and spontaneous. The change of enthalpy (delta H degree) was compensated for by the change in entropy (delta S degree). Relative contribution of hydrophobic interactions in the binding of these compounds to HSA was higher than to AGP or asialoAGP. Sialic acid was not found to impart any significant role in the binding of these compounds to AGP.
Spontaneous Ileal papilloma was found in an 1-1/2 year old female Sprague-Dawley rat. The lesion was first recorded as a tiny bulge on the absorptive surface of the Ileum. Histologically, the outgrowth was recorded as papilloma showing hyperkeratosis, hyperplasia and acanthosis in the transformed epithelium. This appears to be the first report of its kind in the Ileum of rat in Bangladesh.
Acetylcholinesterase (AChE) is demonstrated, apparently for the first time, in developing embryos of the tick Hyalomma rufipes. The enzyme was detected in the neuropile of the oesophageal ganglia and in the nerve endings of the appendages; it was absent from the neurons and neurolemma of the nerve ganglia.
Studies of the effects of host-immunity on the life cycle of Hyalomma rufipes were carried out by allowing the ticks to feed on New Zealand white rabbits under laboratory conditions. The immunity of the rabbit host significantly affected the life cycle of this tick, reducing the percentage recovery of engorged females, their engorged weights and the total number of eggs laid by these females. The viability of the eggs laid by them was also considerably reduced compared to the eggs laid by females fed on naive rabbit hosts. The effects of host immunity were also revealed in the tendency towards three-host development of this species, which otherwise behaved as a two-host tick when fed on non-immune rabbit hosts.
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