Applying spatio-chemical analysis to grassland ecosystems for the illustration of chemoscapes and creation of healthscapes

Grasslands are heterogeneous landscapes composed of a diversity of herbaceous and shrub vegetation that varies not only taxonomically, but biochemically in terms of primary and secondary compounds. Plant Secondary Compounds (PSC) have specific nutritional, medicinal, and prophylactic properties, to which benefits depend upon dosage, type, arrangements, and concentration that changes between and within plants across time and space. The knowledge of the plant content of PSC and their distribution in grazing environments would therefore contribute to the design and creation of healthier foodscapes for ruminants; in other words, healthscapes. Geographic information systems (GIS) have been used extensively for landscape visualization and assessment, through several spatial analysis techniques applied for the creation of virtual maps to add valuable information to a particular environment. Given the knowledge of plants and their composition, GIS emerges as a readily available and low-cost tool to assess and evaluate the distribution of plants with beneficial PSC in large and heterogeneous foodscapes. We present and propose for the very first time, the application and use of GIS to determine the spatial distribution of PSC rich plants with nutraceutical properties to illustrate, visualize, and generate healthscapes for grazing ruminants. We present healthscape maps created using botanical composition analyses and advanced image classification methods to illustrate the distribution of plants regarding their PSC and nutraceutical properties. Such maps add an extra dimension and perspective to plant chemical composition, enabling graziers to visualize in space and time centers of nutrition and prophylactics or medicines, contributing to advanced grazing management decisions toward more productive, sustainable, and healthy grazing systems. The valuable information behind the mapped PSC advances the understanding of the nutritional ecology of grazing environments and foodscapes, introducing a new dimension to the holistic management of pastoral livestock production systems.

The Equipment Used in the SF6 Technique to Estimate Methane Emissions Has No Major Effect on Dairy Cow Behavior

The natural behavior of animals can be disrupted by the techniques and materials of research methodologies. This study aimed to evaluate the effect of the equipment used in the SF₆ tracer technique to estimate enteric methane emissions on the behavior of lactating dairy cows. The cows (n = 24) were allocated to one of two diets: CONTROL and experimental diet (MIX). Behavior was assessed through video recordings between milking times during four phases: 3 days before fitting the cows with the SF₆ equipment (PRE), first 2 days after the cows were fitted with the SF₆ equipment (ADAP), 3 days during methane emission measurements (MEAS), and 2 days after the SF₆ equipment removal (POST). The behaviors recorded included eating, ruminating or idling, resting, and others. Affiliative or agonistic and discomfort behaviors (scratching or pushing the equipment) were also recorded. Lying time was recorded over 14 days using dataloggers fitted to the cows' leg. Milk production and feed intake were recorded daily. MIX cows ruminated more than CONTROL cows (P = 0.05). The cows ruminated more at MEAS than in any other phase (P < 0.01). Time spent idling gradually decreased from PRE to MEAS for MIX cows (P < 0.01). The cows were lying down longer in MEAS than in ADAP and POST (P < 0.01). The time spent lying with the head down was shorter during PRE and ADAP than during POST (P < 0.05). No difference was observed in the occurrence of discomfort or agonistic behaviors (P > 0.05). Affiliative behaviors occurred more often in ADAP than in MEAS (P < 0.05). There was no difference between phases in daily lying time, number of lying bouts per day, or mean bout duration (P > 0.05). Milk production was not influenced by the SF₆ equipment (P > 0.05). Dry matter intake was higher for CONTROL cows (P < 0.01), and it decreased from PRE to MEAS (P < 0.01). However, milk yield did not differ between cows wearing the SF₆ equipment and those without it (P > 0.05). We conclude that the SF₆ equipment had a minimal effect on dairy cow behavior.

Incorporating a Fresh Mixed Annual Ryegrass and Berseem Clover Forage Into the Winter Diet of Dairy Cows Resulted in Reduced Milk Yield, but Reduced Nitrogen Excretion and Reduced Methane Yield

The winter diet of dairy cows in Mediterranean climate regions is usually a total mixed ration with a base of conserved summer crops such as corn silage and alfalfa hay. However, there is increased labor and financial cost related to this kind of feeding, which could be reduced if fresh forages were used in place of some of the conserved forage in the cow diet. The objective of our study was to evaluate the effect of including fresh mixed annual ryegrass and berseem clover into the diet of dairy cows on milk, nitrogen utilization, and methane emission. Twenty-four lactating dairy cows were split into two groups and offered either a diet similar to that usually offered to the cows (CON) or one where a mixture of fresh annual ryegrass and berseem clover was used to partially substitute the corn silage and alfalfa hay in the diet (MIX). Milk yield was recorded automatically, and methane emissions were estimated using the SF₆ tracer technique. The MIX diet had lower crude protein concentration (148 vs. 170 g/kg DM) but higher DM digestibility (81.6 vs. 78.6%) than the CON diet. Compared to the cows offered the CON diet, milk yield was reduced when cows were fed the MIX diet (36.4 vs. 31.9 kg/d), but methane emissions (381 vs. 332 g/d) and nitrogen excretion were also reduced (238 vs. 180 g/d). Nitrogen use efficiency was unaffected (30.8%). In addition, milk from cows fed the MIX diet had a fatty acid profile considered to be more beneficial to human health than that of the milk from cows fed the CON diet. Increasing the protein concentration in the MIX diet, either by direct supplementation or increasing the proportion of legume in the mixed herbage, could overcome the reduction on milk and positively affect methane emission and N use efficiency.

Peripartum Phenomenon in Crioula Lanada Sheep Susceptible and Resistant to Gastrointestinal Nematodes

This study aimed at evaluating parasitological and blood variables in native breed Crioula Lanada sheep belonging to the same herd, to identify and compare susceptible or resistant individuals to gastrointestinal nematodes during gestation and lactation phases. For this purpose, 18 Crioula sheep were used within 2 years of evaluation, in which blood and feces samples and weight of the animals were taken from their 4th month of gestation until the weaning of their lambs, in the 4th month postpartum. Feces samples were used for counting eggs per gram of feces (EPG) and, thus, to identify 12 resistant ewes (EPG < 1,000) and 6 susceptible (EPG > 1,000) to gastrointestinal nematodes. The identification of infective larvae was also performed. Blood was used for analysis of packed cell volume (PCV), eosinophil count, total plasma protein, and immunoglobulin G level against Haemonchus contortus infective larvae. The Kruskal-Wallis non-parametric comparison test was used to evaluate the differences between days of parturition and linear mixed-effects model using package lme4 in R to evaluate the groups. The main parasite species observed in the feces samples were Haemonchus, Trichostrongylus, Oesophagostomum, Ostertagia, and Cooperia in similar proportions in both groups. Susceptible ewes presented peaks of EPG at the beginning of lactation and lower PCV values throughout the study. No difference between groups was observed concerning other blood variables or body weight, but some changes were observed along with the gestation and lactation phases within each group. The physiological response of sheep to nematode infection is a useful tool to identify the most susceptible individuals within the same breed and herd and to select the most genetically resistant individuals.

Black oat grown with common vetch improves the chemical composition and degradability rate of forage

This study aimed to evaluate the effect of cultivating a combination of common vetch (Vicia sativa L.) with black oats (Avena strigosa Schreb.) on the chemical composition of forage and the grazing behavior of heifers. To accomplish this, two paddocks 2500m2 each from a Voisin Rational Grazing management system were divided into three blocks each and then into thirds (278m²) characterizing a randomized block design. Three different forage compositions were distributed into these thirds: oats grown alone, vetch grown alone, and oats grown with vetch. Forage samples were collected after 65 days through the square method. Right after collection, three groups of four heifers each grazed the plots for two hours in a 3x3 double Latin Square design for behavioral observation, grazing simulation through the hand-plucking method, and biting rate determination. Forage samples collected either by hand-plucking or the square method, were analyzed for chemical composition and “in vitro” degradability.  Statistical analyses were performed using the R package lme4. Data were evaluated with linear mixed-effects models. The inclusion of common vetch significantly increased forage production and oat protein content, but decreased the fiber content, which promoted better “in vitro” degradability. Grazing frequency was higher in pasture where oats were grown with vetch, but the biting rate was similar in all the three forage compositions evaluated. Forage collected by the square method did not differ from forage consumed by the heifers, probably meaning low herbage selectivity by heifers.  Furthermore, no interaction of investigated variables occurred between forage compositions and the method of collection. The inclusion of common vetch with black oats increased forage chemical composition, “in vitro” degradability, and forage production, thus having positive effects on the time cows spent grazing.

Toxicity of the amphetamine metabolites 4-hydroxyamphetamine and 4-hydroxynorephedrine in human dopaminergic differentiated SH-SY5Y cells

Amphetamine (AMPH) is a psychostimulant used worldwide by millions of patients in the clinical treatment of attention deficit hyperactivity disorder, narcolepsy or even obesity, and is also a drug of abuse. 4-Hydroxynorephedrine (4-OHNE) and 4-hydroxyamphetamine (4-OHAMPH) are two major metabolites known to persist in the brain longer than AMPH. The contribution of AMPH metabolites for its neurotoxicity is undetermined. We evaluated the toxicity of AMPH and its metabolites 4-OHNE and 4-OHAMPH, obtained by chemical synthesis, in human dopaminergic differentiated SH-SY5Y neurons. Cells were exposed to AMPH (concentration range 0-5mM) or 4-OHAMPH or 4-OHNE (concentration range 0-10mM) for 24 or 48h, and the viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) leakage assays. Results showed that for both AMPH and the metabolites a concentration-dependent toxicity was observed. The toxic concentration 50% (TC₅₀) for AMPH and 4-OHNE following 24h exposure was circa 3.5mM and 8mM, respectively. For 4-OHAMPH the TC₅₀ was not reached in the tested concentration range. N-acetyl cysteine, cycloheximide, l-carnitine, and methylphenidate were able to reduce cell death induced by AMPH TC₅₀. Acridine orange/ethidium bromide staining showed evident signs of late apoptotic cells and necrotic cells following 24h exposure to AMPH 3.50mM. The 4-OHAMPH metabolite at 8.00mM originated few late apoptotic cells, whereas 4-OHNE at 8.00mM resulted in late apoptotic cells and necrotic cells, in a scenario similar to AMPH. In conclusion, the AMPH metabolite 4-OHNE is more toxic than 4-OHAMPH, nonetheless both are less toxic than the parent compound in vitro. The most toxic metabolite 4-OHNE has longer permanence in the brain, rendering likely its contribution for AMPH neurotoxicity.

May exercise prevent addiction?

Amphetamines exert their persistent addictive effects by activating brain's reward pathways, perhaps through the release of dopamine in the nucleus accumbens (and/or in other places). On the other hand, there is a relationship between dopamine and all behavioural aspects that involve motor activity and it has been demonstrated that exercise leads to an increase in the synthesis and release of dopamine, stimulates neuroplasticity and promotes feelings of well-being. Moreover, exercise and drugs of abuse activate overlapping neural systems. Thus, our aim was to study the influence of chronic exercise in the mechanism of addiction using an amphetamine-induced conditioned-place-preference in rats.

Adult male Sprague-Dawley rats were randomly separated in groups with and without chronic exercise. Chronic exercise consisted in a 8 week treadmill running program, with increasing intensity. The conditioned place preference test was performed in both groups using a procedure and apparatus previously established. A 2 mg.kg^-1 amphetamine or saline solution was administered intraperitonially according to the schedule of the conditioned place preference.

Before conditioning none of the animals showed preference for a specific compartment of the apparatus. The used amphetamine dose in the conditioning phase was able to produce a marked preference towards the drug-associated compartment in the group without exercise. In the animals with exercise a significant preference by the compartment associated with saline was observed.

These results lead us to conclude that a previous practice of regular physical activity may help preventing amphetamine addiction in the conditions used in this test.

Vascular non-endothelial nitric oxide induced by swimming exercise stress in rats

1. Herein, we report the effects of acute or chronic forced swimming on vascular responsiveness to angiotensin (Ang) II. 2. The possible involvement of locally produced substances, such as nitric oxide (NO) and prostanoids, in these effects were studied in rat thoracic aorta and superior mesenteric arteries. 3. Chronic, but not acute, swimming reduced the efficacy (maximal effect; Emax) of AngII in thoracic aorta and mesenteric arteries, either with intact or denuded endothelium. 4. The efficacy of AngII was reduced in the presence of indomethacin in mesenteric arteries, but not in the aorta, from either control or chronically stressed rats. 5. Treatment with NG-monomethyl-l-arginine reversed the effect of chronic stress on the response to AngII, suggesting that chronic stress may increase non-endothelial NO activity in both the aorta and mesenteric arteries. 6. The effects of acute and chronic stress on vascular reactivity were selective for AngII because no changes were observed on the effects of phenylephrine.

Acute changes in dopamine release and turnover in rat caudate nucleus following a single dose of methamphetamine

Acute changes in dopamine (DA) turnover were studied in the caudate nucleus (CN) of adult male rats between 0-24 h after a single injection of Methamphetamine (20 mg/kg, ip). A single dose of METH-induced an increase in DA turnover [(DOPAC + HVA)/DA] concomitant with an acute DA release followed by transient DA and DOPAC depletion in the rat CN.

Differential pulse polarographic determination of clotrimazole after derivatization with Procion Red HE-3B

Clotrimazole was shown to react at room temperature in Britton Robinson buffer pH 2 with the reactive dye Procion Red HE-3B. The product exhibited a differential pulse polarographic peak at -0.38 V, which was well separated from the peaks of the reactive dye at -0.08, -0.80 and -0.95 V, and this allowed the indirect determination of clotrimazole in the presence of excess of the reactive dye. The method has been applied satisfactorily to the determination of clotrimazole in pharmaceutical formulations, calibration graphs are rectilinear up to at least 40 microg ml(-1). The detection limit was calculated to be 2.6 microg ml(-1) (3 sigma).

Lipophyllic antioxidants from Iryanthera juruensis fruits

The phytochemical investigation of the hexane extract of Iryanthera juruensis (Myristicaceae) fruits led to the isolation of two tocotrienols and four lignans which exhibited antioxidant activity towards beta-carotene on TLC autographic assay. Two inactive quinones and three omega-arylalkanoic acids were also isolated. The isolates were investigated for their redox properties using cyclic voltammetry. The structure elucidation of the new compounds (one tocotrienol. one quinone and three omega-arylalkanoic acids) was based on analysis of spectroscopic data.

Association of HLA-DR7 with rheumatic fever in the Brazilian population

OBJECTIVE

Rheumatic fever (RF) is a multisystem inflammatory disease that develops as a sequel of untreated throat infection by the group A beta-hemolytic streptococcus. As HLA antigens are known to be important in controlling immunological responsiveness, studies have investigated HLA antigen association with RF. Studies with Caucasians, Black Americans, and Indians showed associations with HLA-DR4, DR2, and DR3, respectively. One study on a Brazilian population suggested an association with HLA-DR7 and HLA-DR53. We investigated the association between RF and antigens HLA-DR7 and DR53 in the white Brazilian population.

METHODS

Thirty-five patients and 209 healthy individuals living in the northern region of the state of Parana, Brazil, were used as test and control groups, respectively. Classical statistical methods were used to compare HLA frequencies between these groups. Results. Data confirmed positive association with HLA-DR7 (46.7 vs. 25.7%; p = 0.015), but not with HLA-DR53 (54.3 vs. 44.5%; p = 0.28). The relative risk and etiologic fractions were 2.4 and 0.27%, respectively.

CONCLUSION

Positive association between HLA-DR7 specificity and RF was observed in the white Brazilian population by 2 independent studies, supporting the hypothesis of the involvement of genetic factors in susceptibility of rheumatic fever.

Modulation of glucose-induced insulin secretion by cytosolic redox state in clonal beta-cells

Nutrient stimulation of pancreatic beta-cells increases the cellular reduced pyridine nucleotide content, but the specific role of cytosolic redox state in glucose-induced insulin release (GIIR) remains undetermined. The role of cytosolic redox state has been assessed (as reflected by the lactate/pyruvate ratio) in nutrient- and non-nutrient-induced insulin release using a recently established glucose-sensitive clonal beta-cell line (BRIN-BD11). Long-term exposure to the NAD+ precursor vitamin nicotinic acid (NA, 100 microM) was used to promote a more oxidized state in the cytosol. Glucose (2-16 mM) evoked a dose-dependent rise in the cytosolic NADH/NAD+ ratio which was linearly related to the extent of GIIR. NA suppressed the glucose-induced rise in the NADH/NAD+ ratio and concomitantly reduced GIIR by 44%. It also inhibited, by 47%, the average glucose-induced rise in cytosolic free Ca2+ concentration ([Ca2+]i, assessed by fura-2 microfluorometry from single cells). The latter effect was not accounted for by a reduction in the activity of voltage-sensitive Ca2+ channels, inasmuch as both high K+- and tolbutamide-induced [Ca2+]i rises remained insensitive to NA exposure. NA did not affect insulin release evoked by any of the depolarizing agents, indicating that steps in the stimulus-secretion coupling cascade distal to Ca2+ influx are insensitive to changes in the cytosolic redox state. It is concluded that GIIR is partially controlled by the cytosolic redox state. Moreover, the impairment in GIIR, caused by a shift toward a more oxidized state in the cytosol, originates from an attenuated [Ca2+]i response. The latter is likely mediated by the influence of cytosolic redox state on specific metabolic pathways (NADH shuttle systems and/or the malonyl-CoA pathway), leading ultimately to enhancement of the activity of ATP-sensitive K+ channels.

[An evaluation of municipal actions in the control of dengue vectors in the region of São José do Rio Prêto, São Paulo, 1989 to 1995]

The aim of this study was to determine the coverage of municipal activities in terms of the control of Aedes aegypti and/or Aedes albopictus by routine house-to-house visits and by emergency activity, carried out between 1989 and 1995 in the area of São José do Rio Prêto, São Paulo State, and to evaluate the cross-correlation between them and the Breteau index (BI). For towns with up to 50,000 real estate properties, the joint coverage by routine and emergency activities was mostly appropriate and the routine activities showed a negative cross-correlation with the BI. For the county seat (more than 50,000 real estate properties), the coverage provided by the above activities was not correlated with the BI. In general, the coverage was inversely proportional to town size. Emergency activities did not show a correlation with the BI in any town size range, proving to be ineffective.

Reduced sensory neuron regeneration by C57BL/6J mice

The tube repair method was used to study peripheral nerve regeneration in five different inbred mouse strains. The sciatic nerve of male adult mice of the C57BL/6J, DBA/1J, C3H/HeJ, BALB/cJ and A/J strains (N = 3) was cut and both proximal and distal nerve stumps were inserted into a polyethylene tube leaving a 4-mm nerve gap. After 6 weeks the tubes containing the regenerated nerve cables were processed for total myelinated axon counts. C57BL/6J mice regenerated significantly fewer myelinated axons (1024 +/- 178, mean +/- SEM) compared to the BALB/cJ (1618 +/- 64), A/J (1788 +/- 95), DBA/1J (2168 +/- 296) or C3H/HeJ (3468 +/- 36) strains. Horseradish peroxidase was applied 3 mm distal to the tube 4 and 40 weeks after tube implantation to further characterize the reduced regenerative response of C57BL/6J mice. Labeled sensory and somatic motor neurons were counted in the spinal cord and L4,5,6 dorsal root ganglia (DRG), respectively. Sciatic nerves from four intact C57BL/6J mice were processed in the same fashion and used as normal controls. No significant difference in the number of motor neurons was detected between the experimental (4 weeks = 663 +/- 74; 40 weeks = 770 +/- 35) and control non-operated (844 +/- 13) animals. However, there were fewer labeled neurons in the DRG of the operated group (4 weeks = 1163 +/- 167; 40 weeks = 2574 +/- 104) compared to the control group (4211 +/- 96). These results indicate that sensory neurons are responsible for the diminished regenerative response in C57BL/6J mice after peripheral nerve transection.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary observations on the diagnosis and transmissibility of canine visceral leishmaniasis in Teresina, n.e. Brazil

A pilot group of 49 dogs and control groups from non-endemic areas were examined serologically for the presence of visceral leishmaniasis (VL) by direct agglutination test (DAT), indirect immunofluorescence (IFAT) enzyme-linked immunosorbent assay (ELISA) and DOT-ELISA. Results indicated that DAT is less sensitive than the other assays and that serology with filter paper blood samples is less sensitive than with serum. Promastigote infections were common in fed Lutzomyia longipalpis taken from a dog kennel inhabited by a dog carrying Leishmania chagasi. Colony-bred Lu. longipalpis readily acquired L. chagasi infection when fed on skin lesions of dogs naturally infected with L. chagasi: a small proportion of flies also became infected when fed on apparently normal skin. Widespread distribution of amastigotes in normal skin of asymptomatic animals was shown both by intensive microscopy and by probing skin biopsy samples with the Lmet2 L. donovani-complex specific DNA probe. It was demonstrated that an immunologically naive dog could be infected by a single experimentally infected sand fly. Abundant amastigotes present within the resultant lesion 22 days later were transmissible to sand flies but serology remained negative at least 45 days after the infective bite. Experimental transmission of canine VL by sand fly bite is a valuable approach for determining which diagnostic procedures are most sensitive, specific and suitable for field application in suburban households.