Pedo‐ecological consequences of lithological discontinuities in soils—examples from Central Europe

Soil profiles having lithological discontinuities, i.e., stratified or layered profiles, occur worldwide. Their genesis as part of the upper‐regolith formation is comparatively well understood, particularly in Central Europe where extensive research on relic periglacial cover beds has been done. But the pedogenetic and ecological implications of lithologically discontinuous soils (LDS) are less well known. Most textbooks rely on the so‐called A‐B‐C‐model as a climate‐driven approach to soil formation. After reviewing definitions and concepts of lithological discontinuities and how they form, we present a pedogenetic model extending the traditional approach by considering substrate genesis and regolith dynamics. The consequences in the interpretation of vertical distributions of parameters of soil acidification and of heavy metals are investigated for typical soil profiles from the W Ore Mountains and the central‐German lowlands. Results show how lithological discontinuities influence the depth gradients and that properties inherited from substrate should be distinguished, if possible, from those developed by pedogenesis.     

Allicin and allicin-derived garlic compounds increase breath acetone through allyl methyl sulfide: use in measuring allicin bioavailability

Progress in establishing systemic pharmacological effects for fresh, crushed garlic (Allium sativum L) in humans has been hindered by (1) the inability to measure allicin bioavailability, (2) lack of direct evidence that allicin has significant systemic activity at doses of garlic normally consumed, and (3) lack of a model for an acute effect. We have addressed these problems by quantifying the increases in breath acetone and breath allyl methyl sulfide (AMS). The area under the 48 h curve was measured in humans after consumption of standardized garlic preparations, allicin, and allicin-derived compounds, at the equivalent of 7 g of crushed garlic. It was shown that the allyl thiosulfinates (mainly allicin) are solely responsible for breath AMS and increased breath acetone. Diallyl trisulfide, diallyl disulfide, ajoene, and S-allylmercaptocysteine, at isomolar dithioallyl, showed the same quantitative effects as allicin. Consumption of AMS at isomolar allyl also gave the same effects as allicin, indicating that AMS is the main metabolite of allicin and is an active metabolite. In conclusion, allicin and allicin-derived compounds are rapidly metabolized to AMS, a compound which stimulates the production of acetone and which can be used to measure the bioavailability of allicin and, hence, the ability of garlic supplements to represent fresh garlic.     

Ultralow calcium requirements of fungi facilitate use of calcium regulating agents to suppress host calcium-dependent defenses,synergizing infection by a mycoherbicide

Infection by many fungi activates a variety of calcium dependent defenses in the hosts, slowing or suppressing the attacker and limiting the efficacy of mycoherbicides. The calcium requirement for fungal growth is so low that it could only be implied based on fungi containing calcium-dependent signaling enzymes. Analytical grade media contain <2 microM calcium, and the addition of specific chelators does not affect fungal growth. Hydrophobic derivatives of the calcium-specific chelator BAPTA designed to traverse plant cuticles were synthesized in order to chelate calcium internally during fungal attack. Some chelators as well as calcium precipitating oxalate and channel blocker verapamil were applied with a weakly mycoherbicidal Colletotrichum coccodes to cotyledons of compatible Abutilon threophrasti. They suppressed calcium dependent callose biosynthesis in the weed and increased virulence but may have affected other calcium-dependent processes that facilitate virulence. The low calcium requirement of fungi, and their high affinity for calcium, allows the application of calcium-regulating agents as synergists for mycoherbicides where the weed uses calcium-dependent defenses.     

Metabolic engineering of plant cells for biotransformation of hesperedin into neohesperidin, a substrate for production of the low-calorie sweetener and flavor enhancer NHDC

Neohesperidin dihydrochalcone (NHDC) is a seminatural, safe, low-calorie sweetener, bitterness blocker, and flavor enhancer with unique properties and applications for the food, beverage, pharmaceutical, and animal feed industries. Current production is limited by the availability of the substrate neohesperidin, a flavonoid that accumulates to significant levels only in the inedible bitter citrus species. We propose a process to convert hesperidin, a tasteless flavonoid extracted from orange peels that are abundant byproducts of the vast orange juice industry, into neohesperidin using metabolic engineering and biotransformation via three steps: (i) extraction of hesperidin from orange peels, (ii) hydrolysis of sugar moieties, and (iii) biotransformation of hesperidin hydrolysis products into neohesperidin. We overcame the current technological bottleneck in biotransformation of hesperidin hydrolysis products into neohesperidin using metabolically engineered plant cell cultures expressing a recombinant flavanone-7-O-glucoside-2-O-rhamnosyltransferase. A small-scale production experiment established the feasibility of the proposed process.     

Cardiomyocyte calcium cycling in a naturally occurring German shepherd dog model of inherited ventricular arrhythmia and sudden cardiac death

ObjectiveTo further characterize arrhythmic mechanisms in German shepherd dogs (GSDs) affected with inherited ventricular arrhythmias by evaluating intracellular calcium cycling and expression of calcium handling genes.AnimalsTwenty five GSDs, 9 backcross dogs, and 6 normal mongrel dogs (controls) were studied. The GSDs and backcross dogs were from a research colony of inherited ventricular arrhythmias. The control research dogs were purchased.MethodsAction potentials (APs) and pseudo-electrocardiograms (ECG) were recorded from left ventricular (LV) wedge preparations of GSDs and normal dogs. Midmyocardial (Mid) LV cells from GSDs and normal mongrels were isolated by enzymatic digestion. Cells were either field stimulated or voltage clamped and calcium transients were measured by confocal microscopy using the indicator Fluo-3AM. Expression of calcium handling genes was measured by quantitative RT-PCR.ResultsMean calcium transient decay (tau) was not different between affected GSDs and control dogs, but striking cell-to-cell variability for tau was observed within affected GSDs and between affected GSDs and controls (P < 0.0001 each); within-dog variability accounted for 75% of total variability. Calcium sparks and afterdepolarizations occurred in GSD but not control cells. ATP2A2/SERCA2a expression was significantly reduced (P = 0.0063) in affected GSDs and inversely correlated (P = 0.0006) with severity of ventricular arrhythmias.ConclusionsGerman shepherd dogs with inherited ventricular arrhythmias have electrophysiologic abnormalities in calcium cycling associated with reduced ATP2A2/SERCA2a expression. These animals provide a unique opportunity to study calcium remodeling at the genetic and molecular level in familial ventricular arrhythmias.     

Surgical decompression,with or without adjunctive therapy,for palliative treatment of primary vertebral osteosarcoma in dogs

Vertebral osteosarcoma (OSA) is the most common primary vertebral tumor in dogs, however studies examining the survival time after surgical decompression of these tumors are limited. There is also limited information regarding the benefit of adjunctive treatments such as radiation therapy or chemotherapy in these patients. The goal of this study was to determine survival time of dogs with primary vertebral OSA after palliative decompressive surgery alone and combined with radiation therapy and/or chemotherapy. Records from 22 client‐owned dogs diagnosed with primary vertebral OSA and treated with decompressive surgery were collected retrospectively from eight referral institutions. Survival time was assessed for dogs treated with surgery alone as well as dogs who received adjunctive radiation therapy and/or chemotherapy. Median survival time in the 12 dogs treated with surgery alone was 42 days (range: 3‐1333 days). The three dogs treated with surgery and chemotherapy had a median survival time of 82 days (range: 56‐305 days). Only one dog was treated with surgery and radiation therapy; this dog survived 101 days. Six dogs were treated with surgery, radiation therapy and chemotherapy; these dogs had a median survival time of 261 days (range: 223‐653 days). Cause of death in all cases that survived the initial postoperative period was euthanasia secondary to confirmed or suspected tumor regrowth. The results of this study suggest that definitive radiation therapy, possibly combined with concurrent chemotherapy, significantly improves survival in dogs treated with palliative decompressive surgery for vertebral OSA and should be the treatment of choice in selected cases.     

Effects of the calcium channel antagonist amlodipine in cats with surgically induced hypertensive renal insufficiency

OBJECTIVE: To determine whether amlodipine besylate decreases systemic arterial blood pressure (BP) and reduces the prevalence of complications in cats with induced hypertensive renal insufficiency. ANIMALS: 20 cats with partial nephrectomy. PROCEDURE: Following reduction in renal mass, 10 cats were administered 0.25 mg of amlodipine/kg, PO, q 24 h (group A). Ten cats served as a control group (group C). Systolic BP (SBP), diastolic BP (DBP), and mean BP (MBP), physical activity, and pulse rate were measured continuously for 36 days by use of radiotelemetric devices. RESULTS: Compared with values for clinically normal cats, SBP, DBP, and MBP were significantly increased in cats of group C. Cats in group A had significant reductions in SBP, DBP, and MBP, compared with values for cats in group C. Albuminuria but not urine protein-to-creatinine ratio was significantly correlated (R2 = 0.317) with SBP in hypertensive cats. Prevalence of ocular lesions attributable to systemic hypertension in group C (7 cats) was greater than that observed in group A (2). Two cats in group C were euthanatized on day 16 because of nuerologic complications attributed to systemic hypertension. One normotensive cat in group A was euthanatized because of purulent enteritis of unknown cause on day 27. CONCLUSIONS AND CLINICAL RELEVANCE: Amlodipine had an antihypertensive effect in cats with coexistent systemic hypertension and renal insufficiency. Its use may improve the prognosis for cats with systemic hypertension by decreasing the risk of ocular injury or neurologic complications induced by high BP.     

Adverse effects and outcome associated with dexamethasone administration in dogs with acute thoracolumbar intervertebral disk herniation: 161 cases (2000-2006)

OBJECTIVE: To determine complications and neurologic outcomes associated with dexamethasone administration to dogs with surgically treated thoracolumbar intervertebral disk herniation, compared with dogs not receiving dexamethasone. DESIGN: Retrospective case series. ANIMALS: 161 dogs with surgically confirmed thoracolumbar disk herniation. PROCEDURES: Medical records from 2 hospitals were used to identify dogs that had received dexamethasone < 48 hours prior to admission (dexamethasone group dogs), dogs that received glucocorticoids other than dexamethasone < 48 hours prior to admission (other-glucocorticoid group dogs), and dogs that received no glucocorticoids (nontreatment group dogs). Signalment, neurologic injury grade, laboratory data, and complications were extracted from medical records. RESULTS: Dexamethasone group dogs were 3.4 times as likely to have a complication, compared with other-glucocorticoid or nontreatment group dogs. Dexamethasone group dogs were 11.4 times as likely to have a urinary tract infection and 3.5 times as likely to have diarrhea, compared with other-glucocorticoid or nontreatment group dogs. No differences in neurologic function at discharge or recheck evaluation were detected among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that treatment with dexamethasone before surgery is associated with more adverse effects, compared with treatment with glucocorticoids other than dexamethasone or no treatment with glucocorticoids, in dogs with thoracolumbar intervertebral disk herniation. In this study population, no difference in outcome was found among groups. These findings suggest that the value of dexamethasone administration before surgery in dogs with thoracolumbar disk herniation should be reconsidered.     

Influence of pond fertilization and feeding rate on growth performance, economic returns and water quality in a small-scale cage-cum-pond integrated system for production of Nile tilapia (Oreochromis niloticus L.)

The effects of pond fertilization and feeding rate on growth, economic returns and water quality were investigated to develop a low‐cost cage‐cum‐pond integrated system for production of Oreochromis niloticus (L.). Hand‐sexed male fingerlings averaging 19±0.39 and 32±0.69 g were stocked in cages and open ponds at 150 fish cage^?1 and 2 fish m^?2 respectively. Fish were cultured for 114 days in five triplicate treatments. Cages were installed into ponds and caged fish were fed a 24% protein diet at 3% (T1) and 6% (T2) body weight day^?1 (BWD) without pond fertilization, and 6% BWD with pond fertilization (T3). The open water in the fourth treatment (T4) was not stocked but contained caged fish, which were fed 6% BWD for the first 57 days followed by 3% BWD for the remaining period. Ponds in the control (T5) had no cages and were neither fertilized nor open‐pond fish fed. Feeding rate and pond fertilization significantly (P<0.05) affected fish growth, profitability and water quality among treatments. Fish growth, feed utilization, fish yield, water quality and profits were significantly (P<0.05) better in T3 than the other treatments. It was concluded that fish production and economic returns were optimized at 6% BWD in fertilized ponds.