Isolation and identification of fungal species from dried date palm (Phoenix dactylifera) fruits sold in Maiduguri metropolis

A total of 360 dried date palm (Phoenix dactylifera) fruits were collected from hawkers, shops and market places within Maiduguri metropolis for the detection of the presence of fungal species. Investigation was based on cultural, microscopically and biochemical tests. Of the 327 (90.83%) fungal isolates recovered on Sabouraud dextrose agar (SDA), Aspergillus niger had the highest percentage of occurrence (39.17%), followed by Aspergillus flavus (17.60%), Mucor species (16.67%), Aspergillus fumigatus (12.50%), Trychophyton rubrum (4.16%), while Candida albicans had the least percentage of occurrences of (0.83%). There is need therefore to appropriately treat this fruit before consumption, to minimize possible mycotic infection.Keywords: Isolation, fungi, date palm, Phoenix dactylifera, Maidugur

Concentrations and snow-atmosphere fluxes of reactive nitrogen at Summit, Greenland

Concentrations and fluxes of NOy (total reactive nitrogen), ozone concentrations and fluxes of sensible heat, water vapor, and momentum were measured from May 1 to July 20, 1995 at Summit, Greenland. Median NOy concentrations declined from 947 ppt in May to 444 ppt by July. NOy fluxes were observed into and out of the snow, but the magnitudes were usually below 1 μmol m−2 h−1 because of the low HNO3 concentration and weak turbulence over the snow surface. Some of the highest observed fluxes may be due to temporary storage by equilibrium sorption of peroxyacetylnitrate (PAN) or other organic nitrogen species on ice surfaces in the upper snowpack. Sublimation of snow at the surface or during blowing snow events is associated with efflux of NOy from the snowpack. Because the NOy fluxes during summer at Summit are bidirectional and small in magnitude, the net result of turbulent NOyexchange is insignificant compared to the 2 μmol m−2 d−1 mean input from fresh snow during the summer months. If the arctic NOy reservoir is predominantly PAN (or compounds with similar properties), thermal dissociation of this NOy is sufficient to support the observed flux of nitrate in fresh snow. Very low HNO3 concentrations in the surface layer (1% of total NOy) reflect the poor ventilation of the surface layer over the snowpack combined with the relatively rapid uptake of HNO3 by fog, falling snow, and direct deposition to the snowpack

Modeling the Measurement: Δ₄₇, Corrections, and Absolute Ratios for Reference Materials

Clumped isotope studies on CO2, Δ47, that is the excess in the isotopologue containing both 13C and 18O at mass 47, can be very useful since they can give temperature estimates independent of the bulk isotopic composition. The measurement itself can be affected by a number of items. Here we develop a data processing model to examine the effects different interferences might have on the final calculated value. It incorporates known issues, for example, pressure baseline, 17O excess, and shifts in absolute ratios for primary reference materials and parameters used for 17O correction. We also included linearity effects as well as differences in isotopologue absolute abundances at a given m/z. What normally would be considered acceptable mass spectrometer 45R and 46R linearity can skew Δ47 results. That is 0.04‰/V and −0.04‰/V linearity on 45R and 46R respectively would also cause an apparent shift in the parameters used for 17O corrections. Measurements were made on CO2(g) equilibrated with water, and we were able to match up the effects seen with model results. Linearity and small differences in amplitude between sample and working reference gas affected Δ47 determination, as did apparent shifts in isotopologue abundances under different conditions. This may (partially) account for discrepancies seen in Δ47-temperature calibrations curves between laboratories. We also developed an easy way to precisely calculate the δ13C and δ18O that works well in spreadsheets without the need for multiple iterations

Adenosine 5'-(2-bromoethyl)-phosphate. A new affinity label for adenine nucleotide sites in proteins

A new adenosine analogue adenosine 5'-(2-bromoethyl)-phosphate has been synthesized. The reactive moiety, a bromoalkyl group, has the ability to react with the nucleophilic side chains of several amino acids. This compound reacts with NAD-dependent isocitrate dehydrogenase from pig heart, causing inactivation. Addition of the allosteric regulator ADP to the reaction mixture protects the enzyme from loss of activity. A second adenosine analogue has been synthesized, adenosine 5'-(n-propyl)-phosphate, which is used to assess any effects that might arise from the noncovalent interaction of adenosine 5'-(2-bromoethyl)-phosphate with the enzyme. It is proposed that adenosine 5'-(2-bromoethyl)-phosphate reacts with an adenine nucleotide site on isocitrate dehydrogenase and that this compound may have general applicability as an affinity label of catalytic and regulatory adenine nucleotide sites in proteins