16S-23S and 23S-5S intergenic spacer regions of Streptococcus thermophilus and Streptococcus salivarius,primary and secondary structure

The 16S-23S intergenic spacer region (spacer region 1) of Streptococcus salivarius, S. thermophilus, and Lactococcus lactis subsp. cremoris and the 23S-5S intergenic spacer region (spacer region 2) of S. salivarius and L. lactis subsp. cremoriswere sequenced and compared with the spacer regions 1 and 2 of other streptococci. A high degree of intraspecific conservation was observed for S. thermophilus and L. lactis, and very similar sequences were found for S. salivarius and S. thermophilus. Whereas spacer region 1 is highly conserved in the genus Streptococcus sensu-stricto,only the tRNA gene and the rRNA processing stems are highly conserved in the three genera: Streptococcussensu-stricto, Lactococcus, and Enterococcus. The presence of a unique tRNA^Ala gene without the 3 terminal CCA sequence seems to be a general feature of the streptococci spacer region 1. A secondary structure model was built to show the interaction between the spacer regions 1 and 2 of S. thermophilus and S. salivarius. The rapid evolution of spacer region 1 in streptococci is in part due to insertions and deletions of small RNA stem/loop structures.     

Effectiveness of naturally occurring Aphis gossypii on tomato plants as a bio-indicator for heavy metals in Riyadh and Hafar Al-Batin,Saudi Arabia

Although certain pollutants can be biologically degraded by microorganisms, rendering their impact short-term, others can not be impaired, such that their effect persists. The present study evaluates the effectiveness of using a field-collected aphid, Aphis gossypii, as a bio-indicator for heavy metals in tomato farms in Riyadh and Hafar Al-Batin, Saudi Arabia. Heavy metals were selected (Cd, Cu, Zn, and Pb) and measured for comparative screening in field-collected plants, soil, and aphids using inductively coupled plasma-mass spectrometry (ICP-MS). Field-collected aphids from both studied regions were identified as Aphis gossypii. In Riyadh, there was no significant difference observed for Cd, Cu, and Zn for all experimental samples, while, Pb was showed differences among samples especially tomato leaves None of the studied samples in Hafar Al-Batin were showed statistically significant differences in Cd, in reverse to significant differences in the other heavy metals. Comparing concentrations of selected heavy metals between the two studied regions was showed that neither region showed a significant difference in heavy metals except for Cu. This study demonstrates that tomato leaf samples showed the highest concentrations of most studied heavy metals, followed by soil, then aphids. Aphids were utilized as a bio-indicator of heavy metals in the studied regions.     

Combined therapy of oncolytic Newcastle disease virus and rhizomes extract of Rheum ribes enhances cancer virotherapy in vitro and in vivo

Molecular Biology Reports - Phytotherapy has been used to treat a different type of diseases including cancer for a long time, and it was a source for different active anti-tumor agents. Oncolytic...     

Iron and nickel complexes with heterocyclic ligands: Stability,synthesis, spectral characterization,antimicrobial activity,acute and subacute toxicity

The synthesis and characterization by elemental analysis, emission atomic spectroscopy, TG measurements, magnetic measurements, FTIR, ¹H NMR, UV–visible spectra and conductivity of a series of iron (II) and nickel (II) complexes with two heterocyclic ligands (L¹(SMX): sulfamethoxazole and L²(MIZ): metronidazole) used in pharmaceutical field and with a new ligand derived benzoxazole (L³(MPBO): 2-(5-methylpyridine-2-yl)benzoxazole), were reported. The formulae obtained for the complexes are: [M(L¹)₂ Cl₂]·nH₂O, [M(L²)₂Cl₂(H₂O)₂]·H₂O and [M(L³)₂(OH)₂]·nH₂O. Stability constants of these complexes have been determined by potentiometric methods in water–ethanol (90:10, v/v) mixture at a 0.2 mol L^?1 ionic strength (NaCl) and at 25.0 ± 0.1 °C. Sirko program was used to determine the protonation constants as well as the binding constants of three species [ML₂H₂]²⁺, [ML₂] and [ML]²⁺. The antimicrobial activity of the ligands and complexes was evaluated in vitro against different human bacteria and fungi using agar diffusion method.Iron sulfamethoxazole complex showed a remarkable inhibition of bacteria growth especially on Staphylococcus aureus and P. aeruginosa. The iron metronidazole complex is active against yeasts especially on Candida tropicalis strain. Nickel complexes presented different antibacterial and antifungal behavior's against bacteria and fungal.The acute toxicity study revealed that the iron complexes are not toxic at 2000 mg/kg dose orally administrated.LD₅₀ for nickel complexes was determined using graphical method.No significant differences in the body weights between the control and the treated groups of both rat sexes in subacute toxicity study using for iron complexes. Hematological and clinical blood chemistry analysis revealed no toxicity effects of the iron complexes. Pathologically, neither gross abnormalities nor histopathological changes were observed for these complexes.     

Characterization of a cysteine protease from wheat Triticum aestivum (cv. Giza 164)

Enzymes, especially proteases, have become an important and indispensable part of the processes used by the modern food and feed industry to produce a large and diversified range of products for human and animal consumption. A cysteine protease, used extensively in the food industry, was purified from germinated wheat Triticum aestivum (cv. Giza 164) grains through a simple reproducible method consisting of extraction, ion exchange chromatography and gel filtration. The molecular weight of the enzyme was estimated to be 61000+/-1200-62000+/-1500 by SDS-PAGE and gel filtration. The cysteine protease had an isoelectric point and pH optimum at 4.4 and 4.0, respectively. The enzyme exhibited more activity toward azocasein than the other examined substrates with K(m) 2.8+/-0.15 mg azocasein/ml. In addition, it had a temperature optimum of 50 degrees C and based on a heat stability study 55% of its initial activity remained after preincubation of the enzyme at 50 degrees C for 30 min prior to substrate addition. All the examined metal cations inhibited the enzyme except Co(2+), Mg(2+), Mn(2+) and Li(+). The proteolytic activity of the enzyme was inhibited by thiol-specific inhibitors, whereas iodoacetate and p-hydroxymercuribenzoate caused a competitive inhibition with Ki values 6+/-0.3 mM and 21+/-1.2 microM, respectively. Soybean trypsin inhibitor had no effect on the enzyme. The enzyme activity remained almost constant for 150 days of storage at -20 degrees C. The properties of this enzyme, temperature and pH optima, substrate specificity, stability and sensitivity to inhibitors or activators, meet the prerequisites needed for food industries.     

Rheological characteristics of microbial suspensions of Pseudomonas aeruginosa and Bacillus cereus

The rheological properties of the bacteria Pseudomonas aeruginosa and Bacillus cereus have been investigated. The apparent viscosity of the bacterial suspensions has been measured at different conditions. The results showed that the bacterial suspensions' apparent viscosity increased with increasing biomass concentration of each of these strains. The P. aeruginosa suspension followed shear thinning behavior while B. cereus suspension followed shear thickening behavior. The shear stress versus shear rate experimental data were best represented by the Herschel-Bulkley model. The apparent viscosity of the P. aeruginosa and B. cereus suspensions decreased with increasing temperature. The relationship between the apparent viscosity and the shearing time highlighted the rheopectic behavior of the suspensions used in this work.     

Maternal Hypoxia Decreases Capillary Supply and Increases Metabolic Inefficiency Leading to Divergence in Myocardial Oxygen Supply and Demand

Maternal hypoxia is associated with a decrease in left ventricular capillary density while cardiac performance is preserved, implying a mismatch between metabolism and diffusive exchange. We hypothesised this requires a switch in substrate metabolism to maximise efficiency of ATP production from limited oxygen availability. Rat pups from pregnant females exposed to hypoxia (FIO₂=0.12) at days 10-20 of pregnancy were grown to adulthood and working hearts perfused ex vivo. ¹⁴C-labelled glucose and ³H-palmitate were provided as substrates and metabolism quantified from recovery of ¹⁴CO₂ and ³H₂O, respectively. Hearts of male offspring subjected to Maternal Hypoxia showed a 20% decrease in cardiac output (P<0.05), despite recording a 2-fold increase in glucose oxidation (P<0.01) and 2.5-fold increase (P<0.01) in palmitate oxidation. Addition of insulin to Maternal Hypoxic hearts, further increased glucose oxidation (P<0.01) and suppressed palmitate oxidation (P<0.05), suggesting preservation in insulin signalling in the heart. In vitro enzyme activity measurements showed that Maternal Hypoxia increased both total and the active component of cardiac pyruvate dehydrogenase (both P<0.01), although pyruvate dehydrogenase sensitivity to insulin was lost (NS), while citrate synthase activity declined by 30% (P<0.001) and acetyl-CoA carboxylase activity was unchanged by Maternal Hypoxia, indicating realignment of the metabolic machinery to optimise oxygen utilisation. Capillary density was quantified and oxygen diffusion characteristics examined, with calculated capillary domain area increased by 30% (P<0.001). Calculated metabolic efficiency decreased 4-fold (P<0.01) for Maternal Hypoxia hearts. Paradoxically, the decline in citrate synthase activity and increased metabolism suggest that the scope of individual mitochondria had declined, rendering the myocardium potentially more sensitive to metabolic stress. However, decreasing citrate synthase may be essential to preserve local PO₂, minimising regions of hypoxia and hence maximising the area of myocardium able to preserve cardiac output following maternal hypoxia.     

Disaccharidase activities in camel small intestine: biochemical investigations of maltase-glucoamylase activity

Disaccharidases (maltase, cellobiase, lactase, and sucrase), alpha-amylase, and glucoamylase in the camel small intestine were investigated to integrate the enzymatic digestion profile in camel. High activities were detected for maltase and glucoamylase, followed by moderate levels of sucrase and alpha-amylase. Very low activity levels were detected for lactase and cellobiase. Camel intestinal maltase-glucoamylase (MG) was purified by DEAE-Sepharose and Sephacryl S-200 columns. The molecular weight of camel small intestinal MG4 and MG6 were estimated to be 140,000 and 180,000 using Sephacryl S-200. These values were confirmed by SDS-PAGE, where the two enzymes migrated as single subunits. This study encompassed characterization of MGs from camel intestine. The Km values of MG4 and MG6 were estimated to be 13.3 mM and 20 mM maltose, respectively. Substrate specificity for MG4 and MG6 indicated that the two enzymes are maltase-glucoamylases because they catalysed the hydrolysis of maltose and starch with alpha-1,4 and alpha-1,6 glycosidic bonds, but not sucrose with alpha-1,2 glycosidic bond which was hydrolyzed by sucrase-isomaltase. Camel intestinal MG4 and MG6 had the same optimum pH at 7.0 and temperature optimum at 50 degrees C and 40 degrees C, respectively. The two enzymes were stable up to 50 degrees C and 40 degrees C, followed by strong decrease in activity at 60 degrees C and 50 degrees C, respectively. The effect of divalent cations on the activity of camel intestinal MG4 and MG6 was studied. All the examined divalent cations Ca(2+), Mn(2+), Mg(2+), Co(2+) and Fe(3+) had slight effects on the two enzymes except Hg(2+) which had a strong inhibitory effect. The effect of different inhibitors on MG4 and MG6 indicated that the two enzymes had a cysteine residue.     

Comparison of gas chromatography-mass spectrometry and high-performance liquid chromatography with coulometric electrode array detection for determination of alkylresorcinol metabolites in human urine

Alkylresorcinols (AR) are amphiphilic compounds present at high concentrations in the outer parts of wheat and rye kernels. Due to their specificity to whole grain and bran products of these cereals, AR and their metabolites have been proposed as biomarkers for intake of such foods. Two alkylresorcinol metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA), have previously been quantified in human urine using two different methodologies: high-performance liquid chromatography coupled to a coulometric electrode array detector (HPLC-CEAD) and gas chromatography in combination with mass spectrometry (GC-MS). In this study, these two methodologies were compared by analysing 114 urine samples from free-living Swedish subjects consuming their habitual diet. Data were evaluated by graphical investigation of difference-plots and statistical inference of agreement was assessed by weighted Deming regression analysis. The median DHBA concentrations were 11 μM (GC-MS) and 13 μM (HPLC-CEAD), respectively. Both difference-plot and regression analysis showed a small but statistically significant additive bias, with HPLC-CEAD resulting in a slightly higher DHBA concentration than GC-MS. The median concentration of DHPPA was 18 μM for both methods. Examination of the difference-plot of DHPPA did not indicate any systematic difference between the methods, but regression analysis showed small but statistically significant constant and proportional biases. The conclusion was that the two methodologies are equally suitable for analysis of alkylresorcinol metabolites in human urine and that any small systematic differences observed are most likely of limited practical importance.