Physical and chemical characteristics of meat from lambs fed sorghum silage with cashew bagasse.

This study was conducted to evaluate the effects of replacing forage sorghum for dehydrated cashew bagasse (DCB) in the proportions of 0; 8; 16 and 24%, based on the natural matter at the time of ensiling on the physicochemical parameters of meat from feedlot lambs. None of the physical parameters evaluated showed a significant difference between the substitution levels of sorghum forage for DCB. The final pH obtained in this study showed a value above the recommended for freshly slaughtered meat from animals 24 hours in refrigeration, being considered DFD meat (dark, firm and dry). Regarding the chemical parameters, it was observed that there were no significant differences between the levels of substitution of sorghum forage for DCB to variable moisture and ash was perceived negative linear effect for protein and quadratic effect on lipid levels meat. The replacement of forage sorghum up to 24% of dehydrated bagasse cashew the ensilage does not compromise the quality of the meat, however, the substitution of 8% is to be preferred because it provides meats with lower lipid content.

Extended spider cognition.

There is a tension between the conception of cognition as a central nervous system (CNS) process and a view of cognition as extending towards the body or the contiguous environment. The centralised conception requires large or complex nervous systems to cope with complex environments. Conversely, the extended conception involves the outsourcing of information processing to the body or environment, thus making fewer demands on the processing power of the CNS. The evolution of extended cognition should be particularly favoured among small, generalist predators such as spiders, and here, we review the literature to evaluate the fit of empirical data with these contrasting models of cognition. Spiders do not seem to be cognitively limited, displaying a large diversity of learning processes, from habituation to contextual learning, including a sense of numerosity. To tease apart the central from the extended cognition, we apply the mutual manipulability criterion, testing the existence of reciprocal causal links between the putative elements of the system. We conclude that the web threads and configurations are integral parts of the cognitive systems. The extension of cognition to the web helps to explain some puzzling features of spider behaviour and seems to promote evolvability within the group, enhancing innovation through cognitive connectivity to variable habitat features. Graded changes in relative brain size could also be explained by outsourcing information processing to environmental features. More generally, niche-constructed structures emerge as prime candidates for extending animal cognition, generating the selective pressures that help to shape the evolving cognitive system.

Host manipulation by parasites through the lens of Niche Construction Theory.

The effect of parasites on host behaviour is generally considered an example of the extended phenotype, implying that parasite genes alter host behaviour to benefit the parasite. While the extended phenotype is a valid perspective supported by empirical examples, this approach was proposed from an evolutionary perspective and it does not fully explain all processes that occur at ecological time scales. For instance, the roles of the ontogenetic environment, memory and learning in forming the host phenotype are not explicitly mentioned. Furthermore, the cumulative effect of diverse populations or communities of parasites on host phenotype cannot be attributed to a particular genotype, much less to a particular gene. Building on the idea that the behaviour of a host is the result of a complex process, which certainly goes beyond a specific parasite gene, we use Niche Construction Theory to describe certain systems that are not generally the main focus in the extended phenotype model. We introduce three niche construction models with corresponding empirical examples that capture the diversity and complexity of host-parasite interactions, providing predictions that simpler models cannot generate. We hope that this novel perspective will inspire further research on the topic, given the impact of ecological factors on both short-, and long-term effects of parasitism.

Coding behavioural data for cladistic analysis: using dynamic homology without parsimony.

Many of the controversies around the concept of homology rest on the subjectivity inherent to primary homology propositions. Dynamic homology partially solves this problem, but there has been up to now scant application of it outside of the molecular domain. This is probably because morphological and behavioural characters are rich in properties, connections and qualities, so that there is less space for conflicting character delimitations. Here we present a new method for the direct optimization of behavioural data, a method that relies on the richness of this database to delimit the characters, and on dynamic procedures to establish character state identity. We use between-species congruence in the data matrix and topological stability to choose the best cladogram. We test the methodology using sequences of predatory behaviour in a group of spiders that evolved the highly modified predatory technique of spitting glue onto prey. The cladogram recovered is fully compatible with previous analyses in the literature, and thus the method seems consistent. Besides the advantage of enhanced objectivity in character proposition, the new procedure allows the use of complex, context-dependent behavioural characters in an evolutionary framework, an important step towards the practical integration of the evolutionary and ecological perspectives on diversity. © The Willi Hennig Society 2010.

Minimal Organizational Requirements for the Ascription of Animal Personality to Social Groups.

Recently, psychological phenomena have been expanded to new domains, crisscrossing boundaries of organizational levels, with the emergence of areas such as social personality and ecosystem learning. In this contribution, we analyze the ascription of an individual-based concept (personality) to the social level. Although justified boundary crossings can boost new approaches and applications, the indiscriminate misuse of concepts refrains the growth of scientific areas. The concept of social personality is based mainly on the detection of repeated group differences across a population, in a direct transposition of personality concepts from the individual to the social level. We show that this direct transposition is problematic for avowing the nonsensical ascription of personality even to simple electronic devices. To go beyond a metaphoric use of social personality, we apply the organizational approach to a review of social insect communication networks. Our conceptual analysis shows that socially self-organized systems, such as isolated ant trails and bee's recruitment groups, are too simple to have social personality. The situation is more nuanced when measuring the collective choice between nest sites or foraging patches: some species show positive and negative feedbacks between two or more self-organized social structures so that these co-dependent structures are inter-related by second-order, social information systems, complying with a formal requirement for having social personality: the social closure of constraints. Other requirements include the decoupling between individual and social dynamics, and the self-regulation of collective decision processes. Social personality results to be sometimes a metaphorical transposition of a psychological concept to a social phenomenon. The application of this organizational approach to cases of learning ecosystems, or evolutionary learning, could help to ground theoretically the ascription of psychological properties to levels of analysis beyond the individual, up to meta-populations or ecological communities.

Diffuse resistance courtship in the scorpion Rhopalurus rochai (Scorpiones: Buthidae).

Male-female courtship signals are frequently subject to arms races, with patterns of behaviour evolving reciprocally to manipulate the reproductive output. Female resistance should be particularly effective when asymmetrical offspring care occurs under low and unpredictable resource distribution, because this would increase maternal costs. Our hypothesis is that under these conditions females will evolve diffuse mating strategies to avoid predictable exploitation by male optimal counter tactics. Mating in scorpions is a complex process, and female resistance occurs through specific behaviours. Here we focus on the scorpion Rhopalurus rochai that inhabits strongly unpredictable arid habitats. We find that courtship success does not rely on typical resistance and stimulatory patterns of behaviours. The screening for prospective partners occurs in the pre-dance phase. Network statistics reveal that unsuccessful courtships are characterised by reduced complexity of interactions, a result typical of non-additive interactions that introduce unpredictability in the network. Unpredictable female resistance reduces male control over female reproduction more effectively than resistance through specific behavioural tactics; it could be selected in cases of extreme parental investment asymmetry, particularly in the context of resource fluctuation, as in the scorpion R. rochai, that inhabits environments with characteristic climatic unpredictability. Female resistance through a diffuse process would function as an extremely efficient screening device. The establishment of diffuse female resistance courtship would preclude the evolution of simple/single male optimal behavioural patterns, and thus the male-female arms races would reach a more complex state, whereby varied and contextually dependent male strategies would be required to settle the reproductive game.

Voriconazole versus a regimen of amphotericin B followed by fluconazole for candidaemia in non-neutropenic patients: a randomised non-inferiority trial.

BACKGROUND: Voriconazole has proven efficacy against invasive aspergillosis and oesophageal candidiasis. This multicentre, randomised, non-inferiority study compared voriconazole with a regimen of amphotericin B followed by fluconazole for the treatment of candidaemia in non-neutropenic patients. METHODS: Non-neutropenic patients with a positive blood culture for a species of candida and clinical evidence of infection were enrolled. Patients were randomly assigned, in a 2:1 ratio, either voriconazole (n=283) or amphotericin B followed by fluconazole (n=139). The primary efficacy analysis was based on clinical and mycological response 12 weeks after the end of treatment, assessed by an independent data-review committee unaware of treatment assignment. FINDINGS: Of 422 patients randomised, 370 were included in the modified intention-to-treat population. Voriconazole was non-inferior to amphotericin B/fluconazole in the primary efficacy analysis, with successful outcomes in 41% of patients in both treatment groups (95% CI for difference -10.6% to 10.6%). At the last evaluable assessment, outcome was successful in 162 (65%) patients assigned voriconazole and 87 (71%) assigned amphotericin B/fluconazole (p=0.25). Voriconazole cleared blood cultures as quickly as amphotericin B/fluconazole (median time to negative blood culture, 2.0 days). Treatment discontinuations due to all-cause adverse events were more frequent in the voriconazole group, although most discontinuations were due to non-drug-related events and there were significantly fewer serious adverse events and cases of renal toxicity than in the amphotericin B/fluconazole group. INTERPRETATION: Voriconazole was as effective as the regimen of amphotericin B followed by fluconazole in the treatment of candidaemia in non-neutropenic patients, and with fewer toxic effects. RELEVANCE TO PRACTICE: There are several options for treatment of candidaemia in non-neutropenic patients, including amphotericin B, fluconazole, voriconazole, and echinocandins. Voriconazole can be given both as initial intravenous treatment and as an oral stepdown agent.

Intrauterine proximity to male fetuses predetermines level of epidermal growth factor in submandibular glands of adult female mice.

Morphological, behavioral, and physiological masculinization of adult female mice that developed in utero between two male fetuses (2M females) has been previously attributed to the significantly higher concentration of testosterone in their fetal blood and amniotic fluid than that in female mice which had not been contiguous to males in utero (0M females). Serum testosterone levels of adult 2M and 0M females are not significantly different. To determine whether exposure of fetuses to different levels of testosterone during prenatal development alters adult biochemical parameters of a system responsive to testosterone, the level of epidermal growth factor (EGF) was measured by radioreceptor assay in the submandibular glands of adult CF-1 mice of known intrauterine position. The concentration of EGF was significantly higher (P less than 0.05) in the glands of 2M females (mean +/- SEM, 0.36 +/- 0.14 nmol/mg dry wt of tissue; n = 6) than that in 0M females (0.05 +/- 0.00 nmol/mg dry wt; n = 8). In contrast, EGF concentration did not differ significantly between the glands of 2M and 0M males (0.51 +/- 0.01 and 1.10 +/- 0.42 nmol/mg dry wt, respectively). EGF levels were also determined in the submandibular glands from adult animals of unknown intrauterine position which were gonadectomized and then treated with testosterone and estradiol. The concentrations of EGF in the glands of gonadectomized males and females were similar (0.13 +/- 0.01 and 0.23 +/- 0.09 nmol/mg dry wt, respectively). However, there was a significant difference in response to hormonal administration between males and females. The response of females exceeded that of males at 400 and 800 micrograms testosterone/day. These results suggest that the hormonal environment of a fetus, specifically modification of the fetal environment by the production of hormones from adjacent fetuses, is a major factor in the adult expression of testosterone-responsive proteins such as EGF.

Increased binding of epidermal growth factor at preimplantation sites in mouse uteri.

The presence of receptors for epidermal growth factor (EGF) in nonpregnant uteri and the elevation of EGF levels in blood during early pregnancy suggest that EGF and its receptor may play important roles in the early stages of pregnancy. We determined the distribution of EGF receptors in uteri of nonpregnant and pregnant mice during the late preimplantation period (days 4.5-5.0 of pregnancy) using radioautograph and quantitative binding techniques. Radioautography of [125I]EGF binding to cornua from nonpregnant mice showed low levels of specific binding evenly distributed throughout the cornua. In contrast, radioautographs of cornua from pregnant mice showed bands of elevated binding encircling the lumen at sites of preimplantation. Results from radioautography were supported by quantitative analysis of [125I]EGF binding to uterine homogenates from nonpregnant and pregnant mice. Binding of [125I]EGF to uterine membranes was highly specific and time dependent. The average level of specific EGF binding calculated from Scatchard plots of nonpregnant uteri (27 +/- 13 fmol/mg protein) was significantly (P less than 0.05) lower than that in pregnant superovulated uteri (106 +/- 67 fmol/mg protein). Furthermore, specific binding of EGF was significantly (P less than 0.05) higher in preimplantation sites than in the intervening nonimplantation regions from the same uteri (42 +/- 6 vs. 29 +/- 4 fmol/mg protein, respectively). Differences in EGF binding appear to be due to changes in the number of EGF receptors, since half-displacement values (1 nM) were similar in all samples. These results demonstrate that alterations of EGF receptor levels occur at sites where implantation will occur in mouse uteri and support the concept that the transforming growth factor-alpha/EGF receptor and its ligands are involved in implantation of concepti.

Use of the stable peptide, gamma-L-glutamyl-L-tyrosine, as an intravenous source of tyrosine in mice.

The relative insolubility of tyrosine (Tyr) at neutral pH limits amounts of this amino acid in solutions used for total parenteral nutrition (TPN). We have tested the potential of the natural peptide, gamma-L-glutamyl-L-tyrosine (Glu(Tyr], to release Tyr in vivo by making 20-microL injections, containing 2.9 mumol Glu(Tyr) (approximately 80 mumol/kg body weight), into the external jugular veins of mice. Mean concentrations of Glu(Tyr) in plasma were 138.5 and 11.4 mumol/L after 10 and 60 minutes, respectively; plasma Tyr was significantly elevated at 10 minutes, but returned to control levels at 60 minutes. When 5.8 mumol of Glu(Tyr) was injected, levels of Glu(Tyr) and of Tyr were significantly higher at both 10 and minutes than when 2.9 mumol of peptide was injected. Animals showed no evidence of toxicity. Two percent or less of the peptide could be detected in the urine, even in mice injected with 5.8 mumol Glu(Tyr). Pretreatment of mice with acivicin, a potent inhibitor of gamma-glutamyl transpeptidase (GGTase), prevented the increase in plasma Tyr seen after injection of 2.9 mumol Glu(Tyr) and led to higher levels of Glu(Tyr) in the plasma both at 10 and at 60 minutes than seen in mice given the same amount of Glu(Tyr) but no acivicin. The presence of the inhibitor also led to loss of as much as 48% of the administered peptide in the urine in 60 minutes. These data suggest that GGTase catalyzes hydrolysis of intravenous (IV) Glu(Tyr) to release Tyr in vivo. Glu(Tyr) in the blood is not partitioned into red blood cells; it remains in the plasma, available to GGTase, which functions at the external surface of cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of tyrosine-deficient total parenteral nutrition on the synthesis of dihydroxyphenylalanine in neural tissue and the activities of tyrosine and branched-chain aminotransferases.

The poor solubility of tyrosine (Tyr) limits the amount of this amino acid in total parenteral nutrition (TPN). In rats maintained on a standard pediatric TPN mixture, plasma and brain concentrations of Tyr are reduced to about 25% of the levels in chow-fed controls. To determine whether these low concentrations of Tyr affect the synthesis of catecholamines in neural tissue, the rate-limiting step (conversion of Tyr to dihydroxyphenylalanine [DOPA]) is studied by administering NSD-1015 to block the pyridoxal phosphate (PLP)-dependent decarboxylation of DOPA. However, in TPN rats, plasma concentrations of Tyr are increased by drug treatment. Because brain Tyr is also increased, these and other experiments using NSD-1015 clearly overestimate the rate of DOPA synthesis for drug-free rats on TPN. Nevertheless, in TPN rats, there is less DOPA in the brain in one experiment and less DOPA in the olfactory bulbs in another, versus control rats. Further examination of the metabolic effects of NSD-1015 reveals that the drug also elevates the concentration of branched-chain amino acids (BCAAs) in the plasma of TPN rats. These findings result from inhibition by NSD-1015 of the PLP-dependent aminotransferases that initiate catabolism of Tyr in the liver and BCAAs in the muscle. Despite the pronounced reduction in plasma Tyr, TPN rats showed a marked increase in the activity of hepatic Tyr aminotransferase compared with chow-fed controls. Conversely, although TPN elevates BCAA concentrations in plasma, the activity of branched-chain aminotransferase (BCAT) in the heart muscle of TPN rats is not different from control values. Different values but the same relationships are seen in drug-free rats.

Intravenous gamma-glutamyl-tyrosine elevates brain tyrosine but not catecholamine concentrations in normal rats.

A number of clinical situations may benefit from intravenous supplements of tyrosine (Tyr). In total parenteral nutrition (TPN), the supply of Tyr is limited by its poor solubility. In both rats and infants maintained on pediatric TPN, plasma Tyr levels are approximately 30% of normal, and in rat brains Tyr concentrations are similarly reduced. We reported previously that supplementing a TPN solution with the soluble peptide, gamma-glutamyl-Tyr [Glu(Tyr)], normalizes plasma Tyr and doubles brain Tyr in rats. To assess more fully the behavior of intravenous Glu(Tyr) in vivo, 20 mmol/L Glu(Tyr) was infused into the inferior vena cava of rats at rates increased every 2 hours over an 8-hour period (300 to 450 mumol Glu(Tyr)/kg body weight/h). The surgical procedure for catheterization is described. At the maximum rate of infusion, plasma Tyr and Glu(Tyr) concentrations reached mean plateau values of 326 and 252 mumol/L, respectively. Brain Tyr concentrations were 71 and 264 nmol/g wet weight in control rats infused with heparinized saline (SAL group) and rats infused with Glu(Tyr) (PEP group) respectively. No differences were found in concentrations of norepinephrine (NE), dopamine (DA), or homovanillic acid (HVA) in prefrontal cortex (PFC), striatum (STR), or remaining brain (RB) tissue in PEP and SAL rats. We did not detect undergraded Glu(Tyr) in the brain, and less than 0.5% of infused Glu(Tyr) appeared in the urine.

Use of the soluble peptide gamma-L-glutamyl-L-tyrosine to provide tyrosine in total parenteral nutrition in rats.

Limited solubility restricts amounts of tyrosine (Tyr) in amino acid solutions used in total parenteral nutrition (TPN). Excess phenylalanine (Phe) is included in TPN for conversion to Tyr by liver Phe hydroxylase. However, this conversion is limited, especially in infants. We have confirmed that infants receiving TPN have low Tyr concentrations and high Phe/Tyr ratios in plasma compared with published values for enterally fed neonates. Tyr is important in the synthesis of proteins and other biomolecules, including catecholamines in the brain. We tested the soluble peptide gamma-glutamyl-tyrosine (Glu(Tyr)) as a possible precursor of Tyr in TPN. Groups of five rats were given infusions of TPN containing an amino acid mixture simulating a commercial formulation (group A), TPN in which Glu(Tyr) was substituted for half the Phe in the group A solution) (group B), or saline (group C). Control animals (group C) were fed rodent chow. Blood was sampled at 0 time and daily for 4 days. Brains were collected at 96 hours, and aromatic amino acids in plasma and brains were measured by high-performance liquid chromatography. Throughout the experiment, plasma of animals in group A had significantly elevated Phe and reduced Tyr concentrations compared with control values; plasma concentrations in groups B and C were similar. In groups A and B, brain Tyr levels were 31% and 63% of control values, respectively. In group B, Glu(Tyr) was not detected in brains. These data suggest that supplementing current TPN mixtures with Glu(Tyr), which is stable in solution, can produce normal plasma Tyr concentrations and Phe/Tyr ratios and improve the supply of Tyr to the brain.

Vasodepressor syncope induced by lower body negative pressure: possible relevance to +Gz-stress training--a case report.

We present a case report of vasodepressor syncope with brief sinus pause in a 26-year-old male subject following a graded lower body negative pressure (LBNP) challenge culminating at -70 mm Hg. Cessation of the LBNP protocol resulted in the return of heart rate and blood pressure activity to pre-challenge levels. Sinus arrest during central hypovolemic stress has been noted in the literature. Its potential in rare cases during exposure to high levels of LBNP should be noted as increasing numbers of investigators utilize presyncopal LBNP testing to assess the orthostatic responses of pilots and astronauts.

Repeatability and protocol comparability of presyncopal symptom limited lower body negative pressure exposures.

Data on repeatability and comparability of different presyncopal symptom-limited lower body negative pressure (PSL-LBNP) exposure protocols, while scarce, are critical to the interpretation of studies using PSL-LBNP methods. To investigate if PSL-LBNP tolerance, heart rate, and blood pressure were repeatable, 11 subjects were exposed to 4 PSL-LBNP tests; each test occurring at the same time of day, separated by at least 72 h, and using the same protocol. No significant differences were found in either the heart rate or blood pressure responses to the PSL-LBNP or the tolerance indices (cumulative stress index; maximum negative pressure tolerated; and duration of negative pressure exposure). To study the comparability of different PSL-LBNP protocols, nine subjects were exposed randomly to five PSL-LBNP tests using protocols that varied in stage duration but not pressure profile. The protocols had 1-, 3-, 5-, 7-, or 9-min stage durations. These PSL-LBNP exposures were conducted at the same time of day and separated by at least 72 h. While no differences were noted in either the response pattern or magnitude of heart rate or blood pressure to the differing protocols, the cumulative stress index and the duration of negative pressure exposure varied proportionally with the length of the stage durations. With the exception of the 1-min protocol, the maximum negative pressure tolerated did not vary regardless of the protocol used.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasticity, stereotypy, intra-individual variability and personality: handle with care.

Only recently, variability within individuals has become of importance to evolutionary thinking. The boom in the literature on behavioural variability has led to the emergence of concepts such as behavioural plasticity, stereotypy, imprecision, and intra-individual variability (IIV). The proliferation of new terms has resulted in overlapping concepts, spreading confusion in understanding the origins of variability. Here we provide a critical overview of the concepts related to behavioural variability within the individual. We conclude that although there is no overlapping between behavioural plasticity and IIV, these concepts do overlap with stereotypy; they also face problems with ideas of abnormality and absence of function in stereotyped behaviour. We further provide a critical overview of the sometimes confusing relationship between (1) within individual variability, and (2) consistent variability across individuals (personality). We point out that personality is logically independent of both activational plasticity and IIV, because personality emerges at the population level, whereas plasticity and IIV emerge at the individual level. We conclude that, in personality studies, the failure to acknowledge the existence of either internal variability or consistent between-individual differences in internal variability will result in mixing different phenomena, and inhibit building unified accounts from heterogeneous databases.

Network Connectance Analysis as a Tool to Understand Homeostasis of Plants under Environmental Changes.

The homeostasis of plants under environmental constraints may be maintained by alterations in the organization of their physiological networks. The ability to control a network depends on the strength of the connections between network elements, which is called network connectance. Herein, we intend to provide more evidence on the existence of a modulation pattern of photosynthetic networks, in response to adverse environmental conditions. Two species (Glycine max-C3 metabolism, and Brachiaria brizantha-C4 metabolism) were submitted to two environmental constraints (water availability, and high and low temperatures), and from the physiological parameters measured, the global connectance (Cgtotal) and the modules connectance (gas exchange-Cgge and photochemical-Cgpho) were analyzed. Both types of environmental constraints impaired the photosynthetic capacity and the growth of the plants, indicating loss of their homeostasis, but in different ways. The results showed that in general the Cgtotal of both species increased with temperature increment and water deficit, indicating a higher modulation of photosynthetic networks. However, the Cg variation in both species did not influence the total dry biomass that was reduced by environmental adversities. This outcome is probably associated with a loss of system homeostasis. The connectance network analyses indicated a possible lack of correspondence between the photosynthetic networks modulation patterns and the homeostasis loss. However, this kind of analysis can be a powerful tool to access the degree of stability of a biological system, as well as to allow greater understanding of the dynamics underlying the photosynthetic processes that maintain the identity of the systems under environmental adversities.

Resting metabolic rates of two orbweb spiders: a first approach to evolutionary success of ecribellate spiders.

Spiders are considered conservative with regard to their resting metabolic rate, presenting the same allometric relation with body mass as the majority of land-arthropods. Nevertheless, web-building is thought to have a great impact on the energetic metabolism, and any modification that affects this complex behavior is expected to have an impact over the daily energetic budget. We analyzed the possibility of the presence of the cribellum having an effect on the allometric relation between resting metabolic rate and body mass for an ecribellate species (Zosis geniculata) and a cribellate one (Metazygia rogenhoferi), and employed a model selection approach to test if these species had the same allometric relationship as other land-arthropods. Our results show that M. rogenhoferi has a higher resting metabolic rate, while Z. geniculata fitted the allometric prediction for land arthropods. This indicates that the absence of the cribellum is associated with a higher resting metabolic rate, thus explaining the higher promptness to activity found for the ecribellate species. If our result proves to be a general rule among spiders, the radiation of Araneoidea could be connected to a more energy-consuming life style. Thus, we briefly outline an alternative model of diversification of Araneoidea that accounts for this possibility.