The Hertz Corporation

About: The Hertz Corporation is a based out in . It is known for research contribution in the topics: Population & Soil water. The organization has 9562 authors who have published 11044 publications receiving 447929 citations. The organization is also known as: Hertz Rental Car & Hertz Rent-a-Car.

Verticillium chlamydosporium as a biological control agent for Meloidogyne incognita and M. hapla in pot and micro-plot tests

Abstract: Verticillium chlamydosporium multiplied in peaty-sand from inoculum rates of 500, 1,000, 5,000 or 10,000 chlamydospores/g soil to a maximum number of 5.5 × 104 cfu/g soil and survived for at least 8 wk in pots planted with tomato plants inoculated with 1,000 second stage juveniles of Meloidogyne incognita. The fungus survived, but did not multiply, in loamy sand or sand. Establishment of V. chlamydosporium on the rhizoplane of tomato plants was greater in peaty sand than in loamy sand or sand. Nematode control was in general greater in peaty sand (average 59% control) than in the other two soil types (average control in loamy sand 51% and in sand 39%). In a microplot experiment on sandy loam, V. chlamydosporium controlled populations of M. hapla on tomato plants by more than 90%. The fungus multiplied and survived in soil for at least 123 days. More fungus was found in rhizosphere soil than in non-rhizosphere soil. Combining V. chlamydosporium with an aldicarb treatment equivalent to 2.8 kg a.i./ha did not affect the activity of the fungus, and gave better control (98%) than a treatment with V. chlamydosporium or aldicarb alone (90%).

Contribution of straw-derived N to total microbial biomass N following incorporation of cereal straw to soil

Abstract: An experiment was done to see if changes in total soil microbial biomass N and 15 N-labelled biomass N could be measured by fumigation-extraction during the 5–20 day period following addition of 15 N-labelled wheat straw to soil. Nitrogen-15 labelled wheat straw was added to a clay-loam soil at a rate equivalent to 76μg Ng −1 soil, with or without an addition of 50μg, Ng −1 soil as unlabelled NH 4 NO 3 . Measurements were made 5, 12 and 20 days later. Non-amended soil was incubated similarly. Total soil microbial biomass N (biomass N) remained constant throughout the 20 day incubation in the unamended soil. Addition of straw alone increased biomass N from about 46 (in the unamended soil) to about 80 μg Ng −1 soil by day 5, and it remained at this level thereafter. Inorganic N addition caused a further increase in biomass N of about 20 μg N g −1 soil by day 5, it then slowly declined until day 20. About 30% of the N originally in the straw was held in the biomass in the soil incubated with straw alone by day 5 and about 25% when N was added with the straw. These percentages hardly changed upon further incubations, and were equivalent to 23 and 19 μg 15 N-labelled biomass N respectively, meaned over the three sampling times. Thus a relatively large addition of inorganic N with the straw (50 μg N g −1 soil) only slightly decreased the consumption of straw-N by the biomass and did not prolong the complete consumption of the straw-N. It was concluded that fumigation-extraction could reliably measure changes in biomass N and 15 N-labelled biomass N shortly (i.e. at 5 days) after addition of 15 N-labelled straw to soil. Most of the inorganic N initially added with the straw could not be measured 20 days later. While this loss could have been due to denitrification, it seems unlikely under the aerobic incubation conditions used. Other factors may have operated.

Nitric oxide and the haemodynamic profile of endotoxin shock in the conscious mouse.

Abstract: The release of cytokines following administration of endotoxin and the contribution of nitric oxide (NO) to the subsequent haemodynamic profile were investigated in the conscious mouse. Administration of endotoxin (E. Coli, 026:B6, 12.5 mg kg−1, i.v.) elevated the concentration of tumour necrosis factor-α (TNF-α) in the plasma within 0.5 h, reaching a maximum at 2 h and returning to control concentrations by 4 h. In addition, the concentration of interleukin-6 (IL-6) in the plasma was also elevated within 1 h, reaching a maximum at 3 h and remaining elevated throughout the 12 h of study. Endotoxin (12.5 mg kg−1, i.v.) induced the expression of a Ca2+-independent (inducible) NO synthase in the mouse heart and elevated the concentrations of nitrite and nitrate in the plasma within 4 h, reaching a maximum at 12 h. This was accompanied by a progressive fall in blood pressure over the same period. The vasopressor effect of noradrenaline (0.5–4 μg kg−1 min−1, i.v.) administered as a continuous infusion was significantly attenuated 7 h after endotoxin (12.5 mg kg−1, i.v). The NO synthase inhibitor NG-monomethyl-L-arginine HCl (L-NMMA; 1–10 mg kg−1, i.v. bolus) reversed the fall in blood pressure when administered 7 h after endotoxin (12.5 mg kg−1, i.v.). In an attempt to maintain a constant blood concentration, L-NMMA was administered as a continuous infusion (10 mg kg−1 h−1, i.v.), beginning 4 h after a lower dose of endotoxin (6 mg kg−1, i.v.). Such treatment prevented the fall in blood pressure and the elevation of nitrite and nitrate in the plasma throughout the 18 h of observation. The fall in blood pressure following endotoxin (3 mg kg−1, i.v.) was significantly reduced throughout the 18 h of observation in homozygous mutant mice lacking the inducible NO synthase. In summary, we have developed a model of endotoxin shock in the conscious mouse in which an overproduction of NO by the inducible NO synthase is associated with the haemodynamic disturbances. This model, which exhibits many of the characteristics of septic shock in man, will enable the study of the pathology of this condition in more detail and aid the investigation of potential therapeutic agents both as prophylactics and, more importantly, as treatments.