RC Treatment Research Articles

CT-measured pore characteristics of surface and subsurface soils influenced by agroforestry and grass buffers

Permanent vegetative buffers with grass and/or trees are expected to improve soil porosity compared to row crop management, yet little is known about the extent of changes in soil properties with depth and how rapidly these changes take place. The objective of this study was to compare the effects of agroforestry and grass buffers on computed tomography (CT)-measured macropore (diam. > 1000 μm) and coarse mesopore (diam. 200–1000 μm) parameters within 0.50 m soil profiles and to examine relationships between CT-measured pore parameters and saturated hydraulic conductivity ( K sat). Undisturbed soil cores (76 mm diam. by 76 mm long) from a no-till corn ( Zea mays L.)-soybean ( Glycine max (L.) Merr.; RC) rotation, grass buffer (GB), and agroforestry buffer (AB) treatments were collected with six replicates from the 0- to 0.50-m depth in 0.10-m increments on a Putnam silt loam (fine, smectitic, mesic Vertic Albaqualf). Five CT images were acquired throughout each soil core using a medical CT scanner with 0.2 by 0.2 mm pixel resolution and 0.5 mm slice thickness. Soil pore parameters including number of pores, number of macropores, number of coarse mesopores, porosity, macroporosity, coarse mesoporosity, and fractal dimension were analyzed using ImageJ software. Treatment and depth effects were significant for all seven parameters. These seven pore parameters were different between row crop and buffer treatments as well as grass and agroforestry buffer treatments. The GB and AB treatments had 26 and 36 macropores per 2500-mm 2 area, respectively. These numbers were 2 and 2.6 times greater than 14 macropores in the RC treatment. No macropores were detected in the 40 to 50 cm depth of the RC treatment. The fractal dimension of macroporosity for the agroforestry treatment was 1.2 and 1.1 times greater than row crop and grass buffer treatments, respectively. Soil bulk density and saturated hydraulic conductivity were significantly different among the treatments. The fractal dimension accounted for 76% of the variability in K sat. This study concludes that establishment of permanent vegetative buffers improves CT-measured soil parameters and these CT-measured parameters may be used to quantify the effects of management relative to environmental benefits and improved water transport and retention models.

Clipping herbaceous vegetation improves early performance of planted seedlings of the Mediterranean shrub <i>Quercus coccifera</i>

Abstract. We tested how the conditions resulting from alternative management strategies addressed to mitigate abiotic and biotic limitations to plant establishment affect the performance of planted Quercus coccifera seedlings. This species is a xerophytic and heliophillous Mediterranean shrub, of interest for the restoration of abandoned farmland. We hypothesised that release from herb competition by clipping would allow Q. coccifera seedlings to cope more efficiently with water shortage by adjusting their mass allocation pattern. We established three environments of herb competition: absence of competition (AC), reduced competition by clipping (RC), and total competition (TC); and applied two irrigation treatments: low and high irrigation. We measured soil moisture at different depths, above- and below-ground herb biomass, and evaluated seedling responses, such as mortality, growth, biomass allocation, and morphological and physiological features. The TC treatment reduced water availability more than the RC treatment, in agreement with the highest water stress of seedlings under TC conditions. Irrigation increased above- and below-ground herb biomass, whereas clipping reduced herb production. Release of herb competition by clipping increased seedling survivorship by one order of magnitude and resulted in a growth rate comparable to the absence of competition. This growth was mostly related to carbon gain allocated to roots. The competition intensity imposed by treatments was related to a parallel reduction in total plant leaf area, biomass allocated to leaves and shoot:root ratio, and an increase in biomass allocated to roots and leaf mass area. The negative effects of herbs on Q. coccifera seedlings seem the result of competition for both water and light, in contrast with previous research with more mesic Quercus species, for which competition is primarily for water. Clipping of herbs is a feasible technique that greatly improved seedling performance, and thus a valuable alternative to herbicide application, common in native plantations aimed at restoring Mediterranean farmland.

In vivo transfer of antisense oligonucleotide against urinary kininase blunts deoxycorticosterone acetate-salt hypertension in rats.

We have previously reported that the renal kallikrein-kinin system suppressed the development of deoxycorticosterone acetate (DOCA)-salt hypertension. Kinins were degraded in the kidney mainly by carboxypeptidase Y (CPY)-like kininase. Blockade of renal kinin degradation may reduce hypertension in the developmental stage. We constructed an antisense oligonucleotide against rat CPY homologue (5'-CAT-CTC-TGC-TTC-CTT-GTG-TC-3', AS) and its randomized control oligonucleotide (5'-TCC-TTC-CTG-CTT-GAG-TTC-CT-3', RC), and prepared an HVJ-liposome complex that prolongs and increases the effectiveness of the antisense oligonucleotide. Antisense oligonucleotide was transfected (25 nmole rat(-1), in terms of nucleotide) into the kidney from the renal artery. Blood pressure was measured through a catheter inserted into the abdominal aorta. Mean blood pressure (MBP) in DOCA-salt treated (for 2 weeks) Sprague Dawley strain rats was 130+/-3 mmHg (n=11), and was reduced significantly (P<0.05) more by AS transfection (122+/-4 mmHg, n=6) than by RC treatment (137+/-6 mmHg, n=5) 4 days after the transfection. This reduction in MBP was accompanied by increased urinary sodium excretion (AS, 8.4+/-1.5 mmole day(-1); RC, 4.6+/-0.5 mmole day(-1), P<0.05) and a reduction in urinary CPY-like kininase activity. Ebelactone B (5 mg kg(-1), twice a day, p.o.), an inhibitor for urinary CPY-like kininase, also reduced MBP and induced natriuresis to the same degree as AS. Lisinopril, an inhibitor for angiotensin converting enzyme (ACE) failed to reduce the elevated MBP. These results suggest that CPY-like kininase may have more contribution than ACE to degrade kinin in the kidney, and that knockdown of CPY-like kininase in the kidney may partly prevent rat DOCA-salt hypertension.

Chickens show socially facilitated feeding behaviour in response to a video image of a conspecific

This study aimed to assess the suitability of using video images to study social facilitation of feeding behaviour in domestic chickens ( Gallus domesticus). A comparison was made between the chickens' responses to a real bird feeding in an adjacent cage (RB) and a video image of the same bird feeding, displayed on a television screen (VB). The amount of food consumed by the subject bird was significantly greater ( P < 0.05) during the RB treatment than when the stimulus cage was empty (RC). Likewise, the amount of food consumed was significantly greater ( P < 0.05) when the video and sound of a bird feeding (VB) was presented than when the video image was of an empty cage (VC). The number of food pecks, although greater in the RB than in the RC treatment ( P < 0.001). was not significantly different between the VB and VC treatments ( P < 0.07). Dividing each of the 30-min trials into three consecutive 10-min intervals and repeating the analysis, suggested that this lack of overall difference may have been due to the initial novelty of the television screen or to a delay in recognizing and responding to the video image since, by the final 10-min interval, the number of pecks was greater in the VB than in the VC treatment ( P < 0.05). It was concluded that video could be used to study social facilitation of feeding behaviour and, possibly also, of other behaviour patterns which occur less frequently or are not so easily elicited by prior deprivation. Video images may also provide an opportunity to identify the key stimuli in feeding behaviour that elicit the social facilitation, since the sequence of the behavioural components can be edited or the image experimentally manipulated independently of the behaviour of the subject bird.

Suppression of P450IIC12 gene expression and elevation of actin messenger ribonucleic acid levels in the livers of female rats after injection of the interferon inducer poly rI·poly rC

Interferons and interferon inducers cause a reduction in hepatic microsomal cytochrome P450 [AH, reduced-flavoprotein:oxygen oxidoreductase (RH hydroxylating), EC 1.14.14.1] content and drug-metabolizing activities in experimental animals. In the present study, the acute effects of administration of the interferon inducer polyriboinosinic acid · polyribocytidylic acid (poly rI·polyrC) to female rats on expression of the microsomal apoprotein and hepatic mRNA for P450IIC12, a constitutive enzyme comprising a significant fraction of the total P450 in untreated female rats, were examined. Poly rI·poly rC treatment (10mg/kg, i.p.) caused a suppression of P450IIC12 apoprotein that was of greatest magnitude (47% of control levels) 24 hr after injection. P450IIC12 was still suppressed significantly (P<0.05) 48 hr after treatment. The time course of suppression and recovery of P450IIC12 protein, as well as the magnitude of the effect, were similar to those of total microsomal P450 measured spectrophotometrically. P450IIC12 mRNA levels were also suppressed by the poly rI·poly rC treatment, reaching 29% of control values within 24 hr. Comparison of the kinetics of suppression of the P450IIC12 mRNA and apoprotein indicated that at least part of the suppression of the protein is mediated pretranslationally. However, the existence of a posttranslational component could not be excluded. Concomitant with the suppression of P450IIC12, actin mRNA content was found to be elevated by at least 3.6-fold in the livers of poly rI·poly rC-treated female rats, with the maximum effect occuring 12 hr after injection of the drug. This effect of poly rI·poly rC on expression of actin mRNA appeared to be at least partially sex-specific, since in a previous study [Morgan ET and Norman CA, Drug Metab Dispos 18: 649–653, 1990] a significant effect of the interferon inducer on actin expression was not observed in livers of male rats.

Activation of Interferon-Inducible Genes in Mice by Poly rI:rC or Alloantigens

We have examined the effects of synthetic dsRNA (poly rI:rC) treatment or of immunization with irradiated allogeneic cells on the expression in vivo of several interferon (IFN)-inducible genes. For this purpose, DBA/2 mice were injected i.p. once with poly rI:rC, or once and then again 3 weeks later, with irradiated C3H/He spleen cells and the effect of these treatments on the levels of the following mRNAs was determined: 202, 2',5'-oligoadenylate synthetase (2-5A synthetase), class I and class II major histocompatibility antigens, and beta-actin. After poly rl:rC treatment, the levels of the 202 and 2-5A synthetase mRNAs in the spleen and in the bone marrow peaked between 12 and 24 h and decreased thereafter. The class I mRNA levels started to increase at 12 h, peaked at 24 h, and declined thereafter. No increase in class II mRNA expression was observed after poly rl:rC injection, whereas beta-actin levels remained unchanged. Pretreatment of DBA/2 mice with sheep anti-murine IFN-alpha/beta antibodies before poly rI:rC injection strongly diminished the induction of 202 mRNA, indicating that IFN-alpha/beta mediated this induction. When irradiated C3H/He spleen cells were injected into DBA/2 mice, the class I and class II mRNAs in the spleen, but not in the bone marrow, started to increase at 12 h, peaked between 48 and 96 h, and decreased thereafter. No increase in the levels of 202 and 2-5A synthetase mRNAs was detected, whereas beta-actin levels remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of poly rI:rC treatment upon the metabolism of [ 14C]-paracetamol in the BALB/cJ mouse

The effect of the immunomodulator, poly rI:rC, upon the in vivo metabolism of [ 14C]-paracetamol has been investigated in male BALB/cJ mice. In both poly rI:rC treated and control groups of mice the major part of the dose was excreted in the 0–24 hr urine and the major urinary metabolites were the glucuronic acid and sulphate conjugates. The urinary excretion of these two conjugates and of free paracetamol was not significantly altered following poly rI:rC treatment. Following enzymic hydrolysis of glucuronides and sulphates, the 3-cysteine, 3-mercapturate, 3-thiomethyl and 3-methylsulphoxide metabolites of paracetamol were all identified in the 0–24 hr urine together with very small amounts of 3-methoxy paracetamol. Although poly rI:rC treatment reduced the proportional urinary excretion of each of the thio adducts the individual differences were not significant. However, total thio adduct excretion, an indirect estimate of the metabolic activation of paracetamol, was significantly lower following poly rI:rC treatment. This depression in the urinary excretion of thio adducts following poly rI:rC treatment is discussed in relation to possible implications for paracetamol toxicity.

Effect of interferon synthesis upon the metabolism of [carboxyl- 14C]-aspirin in the mouse

The effect of stimulation of interferon (IFN) synthesis with the immunomodulators, polyriboinosinic polyribocytidylic acid (poly rI:rC) and Newcastle Disease Virus (NDV) upon the in vivo metabolism of [ carboxil- 14C]-aspirin was investigated in male mice of three different strains. Following poly rI:rC administration to DBA/2 mice, the metabolic conjugation of salicylic acid with glycine was significantly increased, glucuronidation was little changed and there was an approximately 10-fold reduction in the excretion of the oxidation product, gentisic acid. Prolongation of hexobarbitone-induced sleeping time confirmed the ability of this agent to depress oxidative metabolism in vivo. Poly rI:rC administration to C57BL/6By and BALB/cBy mice resulted in similar changes in aspirin metabolism in vivo. Treatment of C57BL/6By mice with NDV produced high levels of circulating IFN and produced alterations in aspirin metabolism similar to those seen after poly rI:rC treatment. Comparable studies in BALB/cBy mice, which did not produce detectable levels of IFN in response to NDV challenge, revealed no change in the fate of aspirin metabolism following treatment with this agent. These data indicate that the in vivo oxidation of salicylate, but not its conjugation, can be depressed, at least indirectly, by an interferon-associated mechanism.

Effects of cryogenic chilling on beef carcass grade, shrinkage and palatability characteristics

Alternate right or left sides of 90 carcasses were randomly selected and chilled at −70°C for 5 h, held at +16°C for 4 h and held at 1°C for 15 h (rapid chill—RC). The remaining sides were chilled at −7°C for 24 h (conventional chill—CC). Physical measurements and USDA quality grade data were obtained at 24 h post mortem and palatability samples were collected at 3–5 days post mortem. RC sides had 0·9% less shrinkage ( P < 0·05) at 24 h post mortem when compared to paired CC sides. Beef sides that were given the RC treatment had a darker, softer lean ( P < 0·01) and received higher marbling scores ( P < 0·01) at 24 h post mortem than did CC sides. Loin steaks from RC sides had longer sarcomeres, less shear resistance and higher sensory panel tenderness ratings. It may be possible to rapidly chill carcasses with less carcass shrinkage and with no detrimental effects on USDA quality grade or on beef palatability.

Differential effect of poly rI·rC and Newcastle disease virus on the expression of interferon and cellular genes in mouse cells

The expression of type I murine interferon (MuIFN) genes and several other cellular genes was examined in poly rI·rC induced and Newcastle disease virus (NDV) infected mouse cells. Northern analysis of RNA from induced L cells revealed that the MuIFN-αs are expressed efficiently in NDV infected cells but only at low levels in poly rI·rC induced cells. MuIFN- β 1, however, is expressed equally well in cells treated with poly rI·rC or infected with NDV. As shown by the use of a probe specific for poly rI·rC, interferon induction correlates with the cellular uptake of poly rI·rC into the cells. The relative levels of α and β 1 mRNAs in the cells reached a maximum at 10 hr after the induction which indicates coordinate expression of α and β 1 interferon genes. The effect of viral infection on the expression of two murine genes coinduced with interferon (pMIF20/11 and pMIF3/10) and several cellular genes was also examined. While pMIF20/11 is an inducible gene, the pMIF3/10 gene is expressed constitutively in mouse L cells. Viral infection, but not poly rI·rC treatment, enhanced the expression of the pMIF3/10 gene, as well as two other cellular genes; H-2 and c- myc, however, the expression of β-actin gene was unaltered. These data indicate that enhancement of gene expression in virus infected cells in not limited to the interferon system.