Non-involvement of lignin peroxidases and manganese peroxidases in 2,4,5-trichlorophenoxyacetic acid degradation byPhanerochaete chrysosporium

Summary Phanerochaete chrysosporium (ME-446) mineralized 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in high N medium and in malt extract medium in which lignin peroxidases (LIPs) and manganese peroxidases (MNPs) are not produced; furthermore,per mutant of ME-446, which lacks LIPs and MNPs, mineralized 2,4,5-T as well as the wild type. These results indicate that LIPs and MNPs are not required for 2,4,5-T degradation byP. chrysosporium.     

Hybridoma antibody content and production rate in continuous culture: Effect of dilution rate

Summary Hybridoma IND1 viability was 95% for dilution rates (D) ranging from 45 to 100% of _max (0.037 hr^–1). Over this range, the cell concentration and total protein content increased with D. Washout occurred at D=0.041 hr^–1, but the intracellular protein content continued to increase. The high- and low-content modes of the intracellular antibody distribution did not vary with D. The fraction of cells with high antibody content decreased with time, except for an increase at D=0.041 hr^–1. This decrease did not affect the specific antibody production rate, which, like the high- and low-content modes, was independent of D.     

A lumped parameter mathematical model of the splanchnic circulation.

A lumped parameter mathematical model to describe the propulsion of blood in the splanchnic circulation was developed by integrating the principles of mechanics and physiology. A set of governing equations by derived by specifically considering the contractility of the portal vein, hepatic vein, liver sinusoids, and of the draining lymphatics. These equations were then simulated on a computer. The present simulation results substantiate previous experimental observations that hepatic venous pressure leads to portal hypertension and increased liver interstitial fluid volume.     

High-performance anion exchange-chromatography of neutral milk oligosaccharides and oligosaccharide alditols derived from mucin glycoproteins.

High-performance anion-exchange (HPAE) chromatography under alkaline conditions (pH approximately 13) has been used to separate neutral oligosaccharides from human milk as well as oligosaccharide alditols isolated by alkaline borohydride degradation of O-linked glycoproteins having blood group A and H activities. Due to the diminished retention times of the alditols compared to their reducing counterparts, a very low base concentration (approximately 15 mM) was used in the fractionation of oligosaccharide alditols. The method appears to be ineffective in fractionation of monosaccharide alditols. Although the retention times generally increased with increasing oligosaccharide chain length, linkage of Fuc alpha-(1----2) to galactose and by Fuc alpha-(1----3) or Fuc alpha-(1----4) to glcNAc may decrease the retention times of both the alditols and the reducing oligosaccharides. Branching generally increased the retention times for oligosaccharide alditols. The retention times of isomers differing in the position of fucose substitution (LNF-1 vs LNF-2) differed greatly while those of the linkage isomers LNF-2 and LNF-3 were similar but distinct. Pulsed amperometric detection is sensitive at the picomole level both for these underivatized oligosaccharides and alditols. On-line desalting with an ion-exchange membrane has been found to be effective in preparative chromatography of these oligosaccharides for NMR spectroscopy and mass spectrometry.     

Polymorphism of the 3'' open reading frame of the virus associated with the acquired immune deficiency syndrome, human T-lymphotropic virus type III.

The genome of the virus associated with the acquired immune deficiency syndrome (AIDS), human T-lymphotropic virus type III (HTLV-III), includes two open reading frames, not found in other retroviruses. One of these, designated 3' open reading frame (3'orf) is 648 base pairs (bp) in length, and overlaps with the 3' long terminal repeat (LTR) sequences. Sequences of additional HTLV-III clones were determined in order to estimate the level and location of variation within 3'orf, to gain some insight into the function of its protein product. Newly determined sequences are reported for 3'orf of two unintegrated clones of HTLV-III and three cDNA clones made from virion RNA derived from the same cell line infected with pooled blood samples of different patients with AIDS or AIDS-related complex symptoms (ARC). In addition, sequences for 3'orf were derived from an unintegrated viral clone derived from a different cell line infected with a distinct isolate from a single patient. These sequences are compared to those previously reported for six other viral clones. Sequences of 3'orf differ among clones by 1.1-10.4% bp and 2.4-17.0% of predicted amino acids. This represents significantly greater sequence variation than is found in the entire genome on average. Moreover, a functional proviral clone has a termination codon at amino acid residue 124 of this open reading frame. This raises questions concerning the structure, and regulation of expression of the protein encoded by 3'orf.     

Inactivation of the transcription factor <Emphasis Type="Italic">mig1</Emphasis> (<Emphasis Type="Italic">YGL035C</Emphasis>) in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> improves tolerance towards monocarboxylic weak acids: acetic,formic and levulinic acid

Toxic concentrations of monocarboxylic weak acids present in lignocellulosic hydrolyzates affect cell integrity and fermentative performance of Saccharomyces cerevisiae. In this work, we report the deletion of the general catabolite repressor Mig1p as a strategy to improve the tolerance of S. cerevisiae towards inhibitory concentrations of acetic, formic or levulinic acid. In contrast with the wt yeast, where the growth and ethanol production were ceased in presence of acetic acid 5 g/L or formic acid 1.75 g/L (initial pH not adjusted), the m9 strain (Δmig1::kan) produced 4.06?±?0.14 and 3.87?±?0.06 g/L of ethanol, respectively. Also, m9 strain tolerated a higher concentration of 12.5 g/L acetic acid (initial pH adjusted to 4.5) without affecting its fermentative performance. Moreover, m9 strain produced 33% less acetic acid and 50–70% less glycerol in presence of weak acids, and consumed acetate and formate as carbon sources under aerobic conditions. Our results show that the deletion of Mig1p provides a single gene deletion target for improving the acid tolerance of yeast strains significantly.     

Parasitism capacity and searching efficiency of Diaeretiella rapae parasitizing Brevicoryne brassicae on susceptible and resistant canola cultivars

Different cultivars of aplant species can affect the foraging and efficiency of natural enemies, both directly through physical and biochemical properties or indirectly through the herbivore's diet. In this study, the parasitism capacity and functional response of Diaeretiella rapae McIntosh were determined on the cabbage aphid, Brevicoryne brassicae (L.) reared on susceptible (Opera) and resistant (Okapi) canola cultivars under laboratory conditions at 25?±?1?°C, 60?±?5% RH and a16:8?h L:D photoperiod. The parasitoid exhibited Type II and Type III functional responses on the resistant and susceptible cultivars, respectively. The estimated value of searching efficiency (a) was 0.1637?±?0.1095?h^?1 on the resistant cultivar whereas its value was dependent on host density on the susceptible cultivar. The handling times (T_h) on the susceptible and resistant canola cultivars were 0.108?±?0.040 and 0.320?±?0.048?h, respectively. The net parasitism rate (C₀) of the parasitoid wasp varied from 128.09 hosts per parasitoid lifetime on the susceptible to 71.01hosts on the resistant canola cultivar. The transformation rate from host population to parasitoid offspring (Qp) was equal to 1 on both cultivars (C₀?=?R₀). The finite parasitism rate (ω) on the susceptible cultivar (0.819 hosts per parasitoid per day) was significantly higher than that on the resistant one (0.578 hosts per parasitoid per day). In conclusion, canola cultivars affected the performance of D. rapae in controlled small-scale laboratory experiments and compared with the susceptible cultivar, the resistant one had anadverseeffect on the efficiency of the parasitoid.     

Potential of diatom consortium developed by nutrient enrichment for biodiesel production and simultaneous nutrient removal from waste water

Because of the decreasing fossil fuel supply and increasing greenhouse gas (GHG) emissions, microalgae have been identified as a viable and sustainable feedstock for biofuel production. The major effect of the release of wastewater rich in organic compounds has led to the eutrophication of freshwater ecosystems. A combined approach of freshwater diatom cultivation with urban sewage water treatment is a promising solution for nutrient removal and biofuel production. In this study, urban wastewater from eutrophic Hussain Sagar Lake was used to cultivate a diatom algae consortium, and the effects of silica and trace metal enrichment on growth, nutrient removal, and lipid production were evaluated. The nano-silica-based micronutrient mixture Nualgi containing Si, Fe, and metal ions was used to optimize diatom growth. Respectively, N and P reductions of 95.1% and 88.9%, COD and BOD reductions of 91% and 51% with a biomass yield of 122.5 mg L^?1 day^?1 and lipid productivity of 37 mg L^?1 day^?1 were observed for cultures grown in waste water using Nualgi. Fatty acid profiles revealed 13 different fatty acids with slight differences in their percentage of dry cell weight (DCW) depending on enrichment level. These results demonstrate the potential of diatom algae grown in wastewater to produce feedstock for renewable biodiesel production. Enhanced carbon and excess nutrient utilization makes diatoms ideal candidates for co-processes such as CO₂ sequestration, biodiesel production, and wastewater phycoremediation.