Diaminopimelic Acid Synthesis in Cultures of an Escherichia coli Double Auxotroph: Effects of Cultural Conditions

The metabolic response to L-lysine of Escherichia coli ATCC 13002, a lysine-histidine double auxotroph, has been examined in a synthetic medium containing sucrose. In shaken cultures largest amounts of extracellular DAP were produced with an initial lysine concentration of 7·5 mg/1 and in static cultures of 2·5 mg/1. Considerably smaller amounts of DAP accumulated under stationary conditions. In cultures shaken for 20 and 43 h there was an overall decrease in the yields of DAP, expressed in terms of cell biomass and of sucrose consumed, as the initial concentration of lysine was increased from 0·75 mg/1 in steps up to 25 mg/1. The regulatory effect of lysine on DAP production was also observed when lysine was supplied to cultures at a constant rate employing diffusion capsules.     

Preliminary observations on plant-rock type relationships in the Shiraz-Dashte Arjan area,South-West Iran

Summary In the Dashte-Arjan area near Shiraz, rock formations appear to control the distribution of various plant species. The Fars formation (Miocene) and the Asmari-Jahrom formation (Eocene-Oligocen) sediments are characterized by distinet plant species and life forms. Among the characteristic calciphytes of Asmari-Jahrom limestones are Astragalus acutus, Amygdalus lyciodes, Cerasus microcarpa, and Fraxinus rotundifolia. The Fars formation limestones are characterized by Astragulus gossypinus, Acantholimon flexuosum, Noaea mucronata and Phlomis bruguieri, Except for Glycrrhiza glabra, white and red marls seem to have similar species, such as Alhagi maurorum and Carthamus oxyacantha. Gypsum of Fars formation has Berberis integerrima and Rosa beggeriana. Various life forms have been distinguished and were found to be confined to different rock types as well.Nomenclature of species is given in table 1.We are greately indebted to Dr. P.H. Davis and Prof. G. Pontecorvo F.R.S. for critically reading this paper and making some invaluable suggestions. We are grateful to the University Research Grant Commission for providing us a grant for this work. We are also indebted to the Dean, College of Arts & Sciences, Pahlavi University, Shiraz, Iran for providing us with a vehicle during this work.     

Phagocytosis of degenerating myelin in transected feline optic nerve: an immunohistochemical study

The phagocytic activity of neuroglial cells in adult feline degenerating optic nerve was investigated by immunocytochemistry at both light and electron microscopy levels. Degeneration was initiated by unilateral eye enucleation and the segment distal to the transection showing true Wallerian degeneration was examined. Following enucleation, twelve adult domestic cats were examined over a period of seven to 215 days. All cases showed slow clearance of myelin debris and absence of proliferating monocytes throughout the post-enucleation period. All phagocytic cells present were neuroglial cells, and many of these cells expressed oligodendroglial antigens. These findings demonstrate the persistence of an active population of oligodendrocytes that might play an additional functional role during Wallerian degeneration of feline optic nerve.     

Phytoextraction of Ni,Pb and,Cd by duckweeds

Abstract

Heavy metals phytoextraction potential of swollen duckweed (Lemna gibba Linn.) and lesser duckweed (Lemna aequinoctialis Welw.) was determined under greenhouse conditions by exposing to untreated industrial/municipal effluent for a period of 21?days. The nickel (Ni), lead (Pb), and cadmium (Cd) concentrations in water samples were measured weekly and in plant biomass at the termination of experiments. Significant differences (p?<?0.05) between initial and final physicochemical parameters and in heavy metal concentrations of plant and water samples were observed. Periodically measured metal concentrations in mediums revealed that removal percentage was dependent on initial Ni (2.15?mg L^?1), Pb (1.51?mg L^?1), and Cd (0.74?mg L^?1) concentrations. The final metal removal percentages were in the sequence of Ni (97%) > Pb (94%) > Cd (90%) when treated with Lemna gibba L. as compared to control (9–12% reduction). High biomass production of Lemna gibba L. resulted in a large metal reduction in the growth medium and the total plant metal contents were in the sequence of Ni (427?µg) > Pb (293?µg) > Cd (105?µg). The lesser duckweed did not survive under experimental conditions. Based on these results, we concluded that Lemna gibba L. is a good candidate for phytoremediation of wastewater.     

Production, recovery and immunogenicity of the protective antigen from a recombinant strain of Bacillus anthracis

The protective antigen (PA) is one of the three components of the anthrax toxin. It is a secreted nontoxic protein with a molecular weight of 83 kDa and is the major component of the currently licensed human vaccine for anthrax. Due to limitations found in the existing vaccine formulation, it has been proposed that genetically modified PA may be more effective as a vaccine. The expression and the stability of two recombinant PA (rPA) variants, PA-SNKE-ΔFF-E308D and PA-N657A, were studied. These proteins were expressed in the nonsporogenic avirulent strain BH445. Initial results indicated that PA-SNKE-ΔFF-E308D, which lacks two proteolysis-sensitive sites, is more stable than PA-N657A. Process development was conducted to establish an efficient production and purification process for PA-SNKE-ΔFF-E308D. pH, media composition, growth strategy and protease inhibitors composition were analyzed. The production process chosen was based on batch growth of B. anthracis using tryptone and yeast extract as the only source of carbon, pH control at 7.5, and antifoam 289. Optimal harvest time was 14–18 h after inoculation, and EDTA (5 mM) was added upon harvest for proteolysis control. Recovery of the rPA was performed by expanded-bed adsorption (EBA) on a hydrophobic interaction chromatography (HIC) resin, eliminating the need for centrifugation, microfiltration and diafiltration. The EBA step was followed by ion exchange and gel filtration. rPA yields before and after purification were 130 and 90 mg/l, respectively. The purified rPA, without further treatment, treated with small amounts of formalin or adsorbed on alum, induced, high levels of IgG anti-PA with neutralization activities. Journal of Industrial Microbiology & Biotechnology (2002) 28, 232–238 DOI: 10.1038/sj/jim/7000239 Received 28 August 2001/ Accepted in revised form 20 December 2001     

Two simple and rapid methods for the detection of polymer-degrading enzymes on high-resolution, alkaline, cold, in situ-native (HiRACIN)-PAGE and high-resolution, in situ-inhibited native (HiRISIN)-PAGE

Two sensitive, high-resolution and exceedingly versatile methods for the detection of isoenzymes of polymer-degrading enzymes on high-resolution, alkaline, cold, in situ-native (HiRACIN)-PAGE and high-resolution in situ-inhibited, native (HiRISIN)-PAGE are described. Extracellular crude extracts containing xylanases and carboxymethylcellulases from Scopulariopsis sp. and glucoamylases from Aspergillus niger were subjected to non-denaturing PAGE containing substrates in the resolving gel. In case of HiRACIN-PAGE, the enzymes were prevented from degrading their respective substrates during run by carrying out electrophoresis at 4°C and the pH of running and resolving gel buffer systems were increased from 8.5 to 10.6. In case of HiRISIN-PAGE, adding competitive inhibitor of the enzyme, cellobiose, in the resolving gel prevents the degradation of polymer during the run. These techniques were successfully applied, for the first time, to visualize four, three and four sharp and distinct bands of xylanases, glucoamylases and CMCases, respectively.     

Second‐derivative synchronous spectrofluorimetric determination of nebivolol hydrochloride and amlodipine besylate in their combined dosage form

A rapid, simple, accurate and highly sensitive spectrofluorimetric method was developed for the simultaneous analysis of nebivolol hydrochloride (NEB) and amlodipine besylate (AML). The method was based on measuring the synchronous fluorescence intensity of the drugs at Δλ = 40 nm in methanol. Various experimental parameters affecting the synchronous fluorescence of the studied drugs were carefully studied and optimized. The calibration plots were rectilinear over concentration ranges of 0.05–1.5 µg/mL and 0.5–10 µg/mL for NEB and AML with limits of detection (LOD) of 0.010 and 0.051 µg/mL and limits of quantitation (LOQ) of 0.031 and 0.156, respectively. The peak amplitudes (²D) of the second derivative synchronous fluorimetry (SDSF) were estimated at 282 nm for NEB and at 393 nm for AML. Good linearity was obtained over the concentration ranges. The proposed method was successfully applied to the determination of the studied compounds in laboratory‐prepared mixtures, commercial single and laboratory‐prepared tablets. The results were in good agreement with those obtained using the comparison method. The mean percent recoveries were found to be 100.12 ± 0.77 and 99.91 ± 0.77 for NEB and AML, respectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Identification of a recurrent insertion mutation in the LDLR gene in a Pakistani family with autosomal dominant hypercholesterolemia

Familial Hypercholesterolemia (FH) results in elevated levels of blood lipids including total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) with normal triglycerides (TG). This disease is one of the major contributors towards an early onset of coronary heart disease (CHD). The aim of the present study was to identify the genes responsible for causing FH in Pakistani population, for this purpose a large consanguineous FH family was selected for genetic analysis. Serum lipid levels, including TC, TG, LDL-C and high density lipoprotein cholesterol (HDL-C), were determined in patients and healthy controls. In order to find the causative mutation in this family, direct sequencing of the low density lipoprotein receptor (LDLR) gene was performed. In addition the part of the Apolipoprotein-B (APOB) gene containing the mutations R3500Q and R3500W was also sequenced. Affected individuals of the family were found to have raised TC and LDL-C levels. Sequencing revealed an insertion mutation (c.2416_2417InsG) in exon 17 of the LDLR gene in all the affected individuals of the family. Common FH causing APOB mutations were not present in this family. Heterozygous individuals had TC levels ranging from ~300–500 mg/dl and the only homozygous individual with typical xanthomas had TC levels exceeding 900 mg/dl. This is the first report of a known LDLR gene mutation causing FH in the Pakistani population. Despite a large heterogeneity of LDLR mutations there are still some common mutations which are responsible for FH throughout the world.     

Aerobic training increases the expression of adiponectin receptor genes in the peripheral blood mononuclear cells of young men

Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO_2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO_2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis.