Pseudomonads as a factor in the growth of winter wheat (Triticum aestivum L.)

Pseudomonads were isolated from the roots of winter wheat plants. Plants produced from direct-drilling of seeds into plots where crop residues had been burnt were larger and appeared healthier than those from plots where crop residues remained. Tests showed that roots from the plants direct-drilled into the plots where crop residues had been burnt were colonized by fewer pseudomonads which could inhibit plant growth than those from plants produced from plots where crop residues remained. The tests were performed by inoculating wheat seedlings with individual bacterial isolates and measuring root growth. When several wheat cultivars were bioassayed against each of two of the inhibitory pseudomonads, they differed greatly in susceptibility to the adverse effects of the bacteria.     

Variables controlling denitrification from earthworm casts and soil in permanent pastures

Summary Denitrification (using the acetylene block method) was determined in earthworm casts and soils from permanent, drained or undrained pasture plots fertilized with 0 or 200 kg N ha^-1 year^-1 as ammonium nitrate. Rates of N₂O production from soil cores were about three times higher from the fertilized than from the unfertilized plots while drainage had a relatively small effect. Denitrification rates from casts were 3–5 times higher than those from soil irrespective of the drainage treatment. Casts generally had higher NO _inf3 ^sup- , NH _inf4 ^sup+ , and moisture contents, and higher microbial respiration rates than soil. Rates of N₂O production were determined primarily by NO _inf3 ^sup- supply, secondarily by moisture; available C did not appear to limit denitrification in these pastures. Estimates of the potential contribution of casts to denitrification ranges from 10.1% of 29.3 kg ha^-1 year^-1 from the unfertilized, drained plot to 22% of 82.5 kg ha^-1 year^-1 from the fertilized undrained plot.     

Seal lungs collapse during free diving: evidence from arterial nitrogen tensions

Arterial blood nitrogen tensions of free-diving Weddell seals (Leptonychotes weddelli) were measured by attaching a microprocessor-controlled blood pump and drawing samples at depth to determine how these marine mammals dive to great depths and ascend rapidly without developing decompression sickness. Forty-seven samples of arterial blood were obtained from four Weddell seals during free dives lasting up to 23 minutes to depths of 230 meters beneath the sea ice of McMurdo Sound, Antarctica. Peak arterial blood nitrogen tensions of between 2000 and 2500 millimeters of mercury were recorded at depths of 40 to 80 meters during descent, indicating that the seal's lung collapses by 25 to 50 meters. Then arterial blood nitrogen tensions slowly decreased to about 1500 millimeters of mercury at the surface. In a single dive, alveolar collapse and redistribution of blood nitrogen allow the seal to avoid nitrogen narcosis and decompression sickness.     

Polymerase chain reaction with single-sided specificity: analysis of T cell receptor delta chain

In the polymerase chain reaction (PCR), two specific oligonucleotide primers are used to amplify the sequences between them. However, this technique is not suitable for amplifying genes that encode molecules where the 5' portion of the sequences of interest is not known, such as the T cell receptor (TCR) or immunoglobulins. Because of this limitation, a novel technique, anchored polymerase chain reaction (A-PCR), was devised that requires sequence specificity only on the 3' end of the target fragment. It was used to analyze TCR delta chain mRNA's from human peripheral blood gamma delta T cells. Most of these cells had a V delta gene segment not previously described (V delta 3), and the delta chain junctional sequences formed a discrete subpopulation compared with those previously reported.     

Prevention of organ allograft rejection by a specific Janus kinase 3 inhibitor

Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings.     

Stabilization of hydrated electrons in irradiated frozen sugar solutions

Yields of free radicals in irradiated aqueous solutions of saccharides at 77 degrees K are larger and qualitatively different from those observed in the components alone. In addition, a blue color results only with the solution. The mechanism proposed to explain the observations is the stabilization of hydrated electrons by the solute.