Effects of delay sequence in a delay discounting task.

Delay discounting refers to the decrease in subjective value of a reward as the delay until its receipt increases. In the present study we assessed the effects of the sequence of delay blocks (increasing or decreasing) on discounting and the data systematicity using a titrating procedure with human participants. All participants completed the delay discounting task in both an increasing and decreasing sequence of delays. Delays ranged from one day to ten years. We found steeper discounting when the delays were presented in an increasing sequence compared with when they were presented in a decreasing sequence. We also found steeper discounting when participants completed the increasing sequence condition first. Our results agree with other findings reported in the literature and suggest that delay discounting may be affected by prior and subsequent experience.

Sorghum hybrids grown in hydroponics contrast for phosphorus use efficiency

Abstract Phosphorus (P) use efficiency is crucial for sorghum production. P acquisition efficiency is the most important component of P use efficiency. The early-stage evaluation of plant development is a useful tool for identifying P-efficient genotypes. This study aimed to identify sorghum hybrids that are efficient in P use efficiency and assess the genetic diversity among hybrids based on traits related to P acquisition efficiency. Thus, 38 sorghum hybrids and two inbred lines (checks) were evaluated under low and high P in a paper pouch system with nutrient solution. Biomass and root traits related to P efficiency were measured. There was no interaction between genotypes and P levels concerning all evaluated traits. The biomass and root traits, except root diameter, presented smaller means under low P than high P. Efficient and inefficient hybrids under each P level were identified. The genetic diversity assessment grouped these genotypes in different clusters. The hybrids AG1090, MSK326, AG1060, 1G100, AS 4639, DKB 540, and DKB 590 were superior under low-P and high-P. Hybrids SC121, 1236020 e 1167017 presented the lowest means than all other hybrids, under both conditions. The evaluated hybrids showed phenotypic diversity for traits related to P acquisition, such as root length and root surface area, which can be useful for establishing selection strategies for sorghum breeding programs and increasing P use efficiency.

Resumo A eficiência do uso do fósforo (P) é fundamental para a produção de sorgo. A avaliação no estágio inicial do desenvolvimento da planta é uma ferramenta útil para a identificação de genótipos eficientes de P. Este trabalho teve como objetivo identificar híbridos de sorgo que sejam eficientes ao uso de P e avaliar a diversidade genética entre os híbridos com base em características relacionadas à eficiência de aquisição de P. Assim, 38 híbridos de sorgo e duas linhagens (testemunhas) foram avaliados sob baixo e alto P em sistema de pastas de papel com solução nutritiva. Características de biomassa e de raiz relacionadas à eficiência de P foram mensuradas. Não houve interação entre genótipos e níveis de P em todas as características avaliadas. As características de biomassa e raiz, exceto o diâmetro da raiz, apresentaram médias menores sob baixo P em comparação com alto P. Híbridos eficientes e ineficientes sob cada nível de P foram identificados e agrupados quanto à diversidade genética. Os híbridos AG1090, MSK326, AG1060, 1G100, AS 4639, DKB 540 e DKB 590 foram superiores sob baixo-P e alto-P. Os híbridos SC121, 1236020 e 1167017 apresentaram as menores médias que todos os outros híbridos, em ambas condições. Os híbridos avaliados apresentaram diversidade fenotípica para características relacionadas à aquisição de P, como comprimento e área superficial da raiz, o que pode ser útil para estabelecer estratégias de seleção para programas de melhoramento de sorgo e aumentar a eficiência de uso do P.

Sorghum hybrids grown in hydroponics contrast for phosphorus use efficiency / Híbridos de sorgo crescidos em hidroponia contrastam para eficiência de uso de fósforo

Phosphorus (P) use efficiency is crucial for sorghum production. P acquisition efficiency is the most important component of P use efficiency. The early-stage evaluation of plant development is a useful tool for identifying P-efficient genotypes. This study aimed to identify sorghum hybrids that are efficient in P use efficiency and assess the genetic diversity among hybrids based on traits related to P acquisition efficiency. Thus, 38 sorghum hybrids and two inbred lines (checks) were evaluated under low and high P in a paper pouch system with nutrient solution. Biomass and root traits related to P efficiency were measured. There was no interaction between genotypes and P levels concerning all evaluated traits. The biomass and root traits, except root diameter, presented smaller means under low P than high P. Efficient and inefficient hybrids under each P level were identified. The genetic diversity assessment grouped these genotypes in different clusters. The hybrids AG1090, MSK326, AG1060, 1G100, AS 4639, DKB 540, and DKB 590 were superior under low-P and high-P. Hybrids SC121, 1236020 e 1167017 presented the lowest means than all other hybrids, under both conditions. The evaluated hybrids showed phenotypic diversity for traits related to P acquisition, such as root length and root surface area, which can be useful for establishing selection strategies for sorghum breeding programs and increasing P use efficiency.

A eficiência do uso do fósforo (P) é fundamental para a produção de sorgo. A avaliação no estágio inicial do desenvolvimento da planta é uma ferramenta útil para a identificação de genótipos eficientes de P. Este trabalho teve como objetivo identificar híbridos de sorgo que sejam eficientes ao uso de P e avaliar a diversidade genética entre os híbridos com base em características relacionadas à eficiência de aquisição de P. Assim, 38 híbridos de sorgo e duas linhagens (testemunhas) foram avaliados sob baixo e alto P em sistema de pastas de papel com solução nutritiva. Características de biomassa e de raiz relacionadas à eficiência de P foram mensuradas. Não houve interação entre genótipos e níveis de P em todas as características avaliadas. As características de biomassa e raiz, exceto o diâmetro da raiz, apresentaram médias menores sob baixo P em comparação com alto P. Híbridos eficientes e ineficientes sob cada nível de P foram identificados e agrupados quanto à diversidade genética. Os híbridos AG1090, MSK326, AG1060, 1G100, AS 4639, DKB 540 e DKB 590 foram superiores sob baixo-P e alto-P. Os híbridos SC121, 1236020 e 1167017 apresentaram as menores médias que todos os outros híbridos, em ambas condições. Os híbridos avaliados apresentaram diversidade fenotípica para características relacionadas à aquisição de P, como comprimento e área superficial da raiz, o que pode ser útil para estabelecer estratégias de seleção para programas de melhoramento de sorgo e aumentar a eficiência de uso do P.

Antimicrobial, antioxidant activity and phytochemical prospection of Eugenia involucrata DC leaf extracts / Atividade antimicrobiana, antioxidante e prospecção fitoquímica dos extratos das folhas de Eugenia involucrata DC

The species Eugenia involucrata DC. is a plant native to Brazil and is traditionally used for intestinal problems, however, little research has documented about its biological potential and phytochemical profile. Thus, the objective of this study was to carry out preliminary phytochemical prospecting, antimicrobial and antioxidant potential of E. involucrata extracts. Using the E. involucrata leaves, aqueous and organic extracts were obtained using the following solvents (ethanol, methanol, hexane, acetone, dichloromethane and ethyl acetate). The phytochemical prospecting detected the presence of saponins, steroids, flavonoids and tannins in the extracts. Ethanolic and methanolic extracts presented antimicrobial activity for most of the bacterial strains tested, as well as for yeast Candida albicans, with concentrations between 3.12 and 50 mg/mL. The ethanolic and metanolic extract presented high free radical sequestration potential (>90%). The methanol extract showed an IC50 value statistically equal to that found for the commercial antioxidant BHT (p <0.05). The crude extracts obtained with ethanol and methanol were the most promising. These results suggest that methanolic, ethanolic and aqueous extracts are a promising source of natural bioactive.

A espécie Eugenia involucrata DC. é uma planta nativa do Brasil e tradicionalmente utilizada para problemas intestinais, porém, poucas pesquisas documentam sobre seu potencial biológico e perfil fitoquímico. Assim, o objetivo deste trabalho foi realizar uma prospecção fitoquímica preliminar, o potencial antimicrobiano e antioxidante dos extratos de E. involucrata. A partir das folhas de E. involucrata, foram obtidos extratos aquosos e orgânicos com os seguintes solventes (etanol, metanol, hexano, acetona, diclorometano e acetato de etila). A prospecção fitoquímica detectou a presença de saponinas, esteroides, flavonóides e taninos nos extratos. Os extratos etanólico e metanólico apresentaram atividade antimicrobiana para a maioria das cepas bacterianas testadas, assim como para a levedura Candida albicans, com concentrações entre 3,12 e 50 mg/mL. Os extratos etanólico e metanólico apresentaram alto potencial de sequestro de radicais livres (> 90%). O extrato metanólico apresentou IC50 estatisticamente igual ao encontrado para o antioxidante comercial BHT (p <0,05). Os extratos brutos obtidos com etanol e metanol foram os mais promissores. Esses resultados sugerem que os extratos metanólico, etanólico e aquoso são uma fonte promissora de bioativos naturais.

Antimicrobial, antioxidant activity and phytochemical prospection of Eugenia involucrata DC. leaf extracts

Abstract The species Eugenia involucrata DC. is a plant native to Brazil and is traditionally used for intestinal problems, however, little research has documented about its biological potential and phytochemical profile. Thus, the objective of this study was to carry out preliminary phytochemical prospecting, antimicrobial and antioxidant potential of E. involucrata extracts. Using the E. involucrata leaves, aqueous and organic extracts were obtained using the following solvents (ethanol, methanol, hexane, acetone, dichloromethane and ethyl acetate). The phytochemical prospecting detected the presence of saponins, steroids, flavonoids and tannins in the extracts. Ethanolic and methanolic extracts presented antimicrobial activity for most of the bacterial strains tested, as well as for yeast Candida albicans, with concentrations between 3.12 and 50 mg/mL. The ethanolic and metanolic extract presented high free radical sequestration potential (>90%). The methanol extract showed an IC50 value statistically equal to that found for the commercial antioxidant BHT (p 0.05). The crude extracts obtained with ethanol and methanol were the most promising. These results suggest that methanolic, ethanolic and aqueous extracts are a promising source of natural bioactive.

Resumo A espécie Eugenia involucrata DC. é uma planta nativa do Brasil e tradicionalmente utilizada para problemas intestinais, porém, poucas pesquisas documentam sobre seu potencial biológico e perfil fitoquímico. Assim, o objetivo deste trabalho foi realizar uma prospecção fitoquímica preliminar, o potencial antimicrobiano e antioxidante dos extratos de E. involucrata. A partir das folhas de E. involucrata, foram obtidos extratos aquosos e orgânicos com os seguintes solventes (etanol, metanol, hexano, acetona, diclorometano e acetato de etila). A prospecção fitoquímica detectou a presença de saponinas, esteroides, flavonóides e taninos nos extratos. Os extratos etanólico e metanólico apresentaram atividade antimicrobiana para a maioria das cepas bacterianas testadas, assim como para a levedura Candida albicans, com concentrações entre 3,12 e 50 mg/mL. Os extratos etanólico e metanólico apresentaram alto potencial de sequestro de radicais livres (> 90%). O extrato metanólico apresentou IC50 estatisticamente igual ao encontrado para o antioxidante comercial BHT (p 0,05). Os extratos brutos obtidos com etanol e metanol foram os mais promissores. Esses resultados sugerem que os extratos metanólico, etanólico e aquoso são uma fonte promissora de bioativos naturais.

Antimicrobial, antioxidant activity and phytochemical prospection of Eugenia involucrata DC. leaf extracts / Atividade antimicrobiana, antioxidante e prospecção fitoquímica dos extratos das folhas de Eugenia involucrata DC

Abstract The species Eugenia involucrata DC. is a plant native to Brazil and is traditionally used for intestinal problems, however, little research has documented about its biological potential and phytochemical profile. Thus, the objective of this study was to carry out preliminary phytochemical prospecting, antimicrobial and antioxidant potential of E. involucrata extracts. Using the E. involucrata leaves, aqueous and organic extracts were obtained using the following solvents (ethanol, methanol, hexane, acetone, dichloromethane and ethyl acetate). The phytochemical prospecting detected the presence of saponins, steroids, flavonoids and tannins in the extracts. Ethanolic and methanolic extracts presented antimicrobial activity for most of the bacterial strains tested, as well as for yeast Candida albicans, with concentrations between 3.12 and 50 mg/mL. The ethanolic and metanolic extract presented high free radical sequestration potential (>90%). The methanol extract showed an IC50 value statistically equal to that found for the commercial antioxidant BHT (p <0.05). The crude extracts obtained with ethanol and methanol were the most promising. These results suggest that methanolic, ethanolic and aqueous extracts are a promising source of natural bioactive.

Resumo A espécie Eugenia involucrata DC. é uma planta nativa do Brasil e tradicionalmente utilizada para problemas intestinais, porém, poucas pesquisas documentam sobre seu potencial biológico e perfil fitoquímico. Assim, o objetivo deste trabalho foi realizar uma prospecção fitoquímica preliminar, o potencial antimicrobiano e antioxidante dos extratos de E. involucrata. A partir das folhas de E. involucrata, foram obtidos extratos aquosos e orgânicos com os seguintes solventes (etanol, metanol, hexano, acetona, diclorometano e acetato de etila). A prospecção fitoquímica detectou a presença de saponinas, esteroides, flavonóides e taninos nos extratos. Os extratos etanólico e metanólico apresentaram atividade antimicrobiana para a maioria das cepas bacterianas testadas, assim como para a levedura Candida albicans, com concentrações entre 3,12 e 50 mg/mL. Os extratos etanólico e metanólico apresentaram alto potencial de sequestro de radicais livres (> 90%). O extrato metanólico apresentou IC50 estatisticamente igual ao encontrado para o antioxidante comercial BHT (p <0,05). Os extratos brutos obtidos com etanol e metanol foram os mais promissores. Esses resultados sugerem que os extratos metanólico, etanólico e aquoso são uma fonte promissora de bioativos naturais.

Sorghum hybrids grown in hydroponics contrast for phosphorus use efficiency.

Phosphorus (P) use efficiency is crucial for sorghum production. P acquisition efficiency is the most important component of P use efficiency. The early-stage evaluation of plant development is a useful tool for identifying P-efficient genotypes. This study aimed to identify sorghum hybrids that are efficient in P use efficiency and assess the genetic diversity among hybrids based on traits related to P acquisition efficiency. Thus, 38 sorghum hybrids and two inbred lines (checks) were evaluated under low and high P in a paper pouch system with nutrient solution. Biomass and root traits related to P efficiency were measured. There was no interaction between genotypes and P levels concerning all evaluated traits. The biomass and root traits, except root diameter, presented smaller means under low P than high P. Efficient and inefficient hybrids under each P level were identified. The genetic diversity assessment grouped these genotypes in different clusters. The hybrids AG1090, MSK326, AG1060, 1G100, AS 4639, DKB 540, and DKB 590 were superior under low-P and high-P. Hybrids SC121, 1236020 e 1167017 presented the lowest means than all other hybrids, under both conditions. The evaluated hybrids showed phenotypic diversity for traits related to P acquisition, such as root length and root surface area, which can be useful for establishing selection strategies for sorghum breeding programs and increasing P use efficiency.

Antimicrobial, antioxidant activity and phytochemical prospection of Eugenia involucrata DC. leaf extracts.

The species Eugenia involucrata DC. is a plant native to Brazil and is traditionally used for intestinal problems, however, little research has documented about its biological potential and phytochemical profile. Thus, the objective of this study was to carry out preliminary phytochemical prospecting, antimicrobial and antioxidant potential of E. involucrata extracts. Using the E. involucrata leaves, aqueous and organic extracts were obtained using the following solvents (ethanol, methanol, hexane, acetone, dichloromethane and ethyl acetate). The phytochemical prospecting detected the presence of saponins, steroids, flavonoids and tannins in the extracts. Ethanolic and methanolic extracts presented antimicrobial activity for most of the bacterial strains tested, as well as for yeast Candida albicans, with concentrations between 3.12 and 50 mg/mL. The ethanolic and metanolic extract presented high free radical sequestration potential (>90%). The methanol extract showed an IC50 value statistically equal to that found for the commercial antioxidant BHT (p <0.05). The crude extracts obtained with ethanol and methanol were the most promising. These results suggest that methanolic, ethanolic and aqueous extracts are a promising source of natural bioactive.

Integrated genetic and morphological data support eco-evolutionary divergence of Angolan and South African populations of Diplodus hottentotus.

The genus Diplodus presents multiple cases of taxonomic conjecture. Among these the D. cervinus complex was previously described as comprising three subspecies that are now regarded as separate species: Diplodus cervinus, Diplodus hottentotus and Diplodus omanensis. Diplodus hottentotus exhibits a clear break in its distribution around the Benguela Current system, prompting speculation that Angolan and South African populations flanking this area may be isolated and warrant formal taxonomic distinction. This study reports the first integrated genetic [mitochondrial (mt)DNA and nuclear microsatellite] and morphological (morphometric, meristic and colouration) study to assess patterns of divergence between populations in the two regions. High levels of cytonuclear divergence between the populations support a prolonged period of genetic isolation, with the sharing of only one mtDNA haplotype (12 haplotypes were fully sorted between regions) attributed to retention of ancestral polymorphism. Fish from the two regions were significantly differentiated at a number of morphometric (69·5%) and meristic (46%) characters. In addition, Angolan and South African fish exhibited reciprocally diagnostic colouration patterns that were more similar to Mediterranean and Indian Ocean congeners, respectively. Based on the congruent genetic and phenotypic diversity we suggest that the use of hottentotus, whether for full species or subspecies status, should be restricted to South African D. cervinus to reflect their status as a distinct species-like unit, while the relationship between Angolan and Atlantic-Mediterranean D. cervinus will require further demo-genetic analysis. This study highlights the utility of integrated genetic and morphological approaches to assess taxonomic diversity within the biogeographically dynamic Benguela Current region.

Performance of grain sorghum hybrids under drought stress using GGE biplot analyses.

The objective of this study was to estimate the adaptability and stability of grain sorghum hybrids grown under post-flowering water stress and non-stress conditions. The trials were carried out in Nova Porteirinha-MG during the season of 2014 and 2015, and in Teresina-PI in the 2014 season. Twenty-nine-grain sorghum hybrids were evaluated, in a randomized complete block design, with three replications. Plots consisted of four lines with 3 m long. The grain yield data were submitted to the individual variance analysis, having considered the effects of the hybrids as fixed and the other effects as random. The joint analysis was carried out, and when the interaction genotypes x environments was significant, the grain yield data were submitted to the adaptability and stability analysis by the GGE biplot method. A substantial reduction in the grain yield in environments with water stress was found. The highest yielding hybrids under water stress conditions in Nova Porteirinha-MG were 50A50, AG1080, AG1090, DKB550, DKB590, Jade, and BM737, and the highest yielding hybrids under the water stress in Teresina-PI were 1G282, 1G244, and A9721R. Considering all environments, the highest yielding hybrids were 1G282, DKB540, A9721R, 1G100, and AG1090.

Evaluation of grain yield in sorghum hybrids under water stress.

Sorghum grain yield can be significantly affected by climatic changes, especially drought and high temperature. The purpose of this study was to evaluate hybrids of grain sorghum grown under normal irrigation conditions or water stress in order to select those likely to be more tolerant of drought. Forty-nine hybrids were grown in a randomized block design experiment, with three replications. The plots consisted of four rows of 5 m length. Grain yield, weight of 1000 grains, harvest index, days to flowering, and plant height were measured. All of these characteristics were affected by water stress; however, grain yield showed the largest relative reduction. Comparison of the various genotypes showed that some hybrids had an acceptable grain yield under water stress, and maintained a high average yield compared to growth without stress. Several hybrids gave better grain yield than commercial check cultivars: 1170090, 1170092, 1170064, 1167026, 1167064, 1170093, 1167008, 1167029, 0009061, 1167092, 1105647, and 1170019 stood out for their acceptable plant height, earliness, and higher productivity.

Selection indices to identify drought-tolerant grain sorghum cultivars.

Twenty-five cultivars of grain sorghum [Sorghum bicolor (L.) Moench] were examined under both drought stress and normal conditions in 4 experiments. In each condition, genotypes were evaluated in a factorial experiment using a randomized complete block design with 3 replications. Eight drought tolerance indices including stability tolerance index, mean productivity (MP), geometric MP, harmonic mean, stress susceptibility index, tolerance index, yield index, and yield stability index were estimated for each genotype based on grain yield under drought (Ys) and irrigated conditions (Yp). The results indicated that there were positive and significant correlations among Yp and Ys with geometric MP, MP, harmonic mean, and stability tolerance index, indicating that these factors are better predictors of Yp and Ys than tolerance index, stress susceptibility index, yield stability index, and yield index. Based on adjusted means at Yp and Ys, indices geometric MP, MP, harmonic mean, and stability tolerance index, unweighted pair group method with arithmetic mean cluster and biplot analysis, the most tolerant cultivars were '9929020', '9929034', and 'N 95B'.

Companion's effects upon resistance to change.

In order to investigate the effects of a companion's presence on resistance to change, five rats were trained under a multiple schedule comprised of components with high versus low rate of water reinforcement. After response rates became stable, water was given to the subjects prior to the experimental sessions, and these were conducted both in the absence and in the presence of a companion, which also could be responding or merely present. Results showed that the companion's presence increased resistance to satiation, mainly during the component with the higher reinforcement rate. These results suggest that the effect of the companion's presence may interact with reinforcement rate in determining response rate and resistance to satiation.

Learned helplessness: effects of response requirement and interval between treatment and testing.

Three experiments investigated learned helplessness in rats manipulating response requirements, shock duration, and intervals between treatment and testing. In Experiment 1, rats previously exposed to uncontrollable or no shocks were tested under one of four different contingencies of negative reinforcement: FR 1 or FR 2 escape contingency for running, and FR1 escape contingency for jumping (differing for the maximum shock duration of 10s or 30s). The results showed that the uncontrollable shocks produced a clear operant learning deficit (learned helplessness effect) only when the animals were tested under the jumping FR 1 escape contingency with 10-s max shock duration. Experiment 2 isolated of the effects of uncontrollability from shock exposure per se and showed that the escape deficit observed using the FR 1 escape jumping response (10-s shock duration) was produced by the uncontrollability of shock. Experiment 3 showed that using the FR 1 jumping escape contingency in the test, the learned helplessness effect was observed one, 14 or 28 days after treatment. These results suggest that running may not be an appropriate test for learned helplessness, and that many diverging results found in the literature might be accounted for by the confounding effects of respondent and operant contingencies present when running is required of rats.

Aging and gender affect the response of thyrotropin (TSH) to gastrin releasing peptide (GRP) in rats.

We had previously shown that GRP acts directly at the pituitary gland inhibiting basal and TRH-stimulated TSH secretion in adult male rats. In this study we showed a gender dimorphism in this response of old animals pituitaries to GRP. In both female and male young adult animals, GRP-incubated pituitaries showed approximately 50% less basal and TRH-stimulated TSH secretion to the medium, without affecting the pituitary content of TSH. However, GRP did not have any significant effect upon TSH secretion in old male rats, but the old female showed the same degree of response to GRP as the young adult female rat, regarding basal and TRH-stimulated TSH secretion, while the TSH pituitary content after GRP incubation was higher than that of the young female group. Our data suggest a loss of thyrotrope responsiveness to GRP in aged male rats that could contribute to the decrease in TSH pituitary stores leading to lower basal and TRH-stimulated TSH secretion. Meanwhile, the preservation of GRP responsiveness could help in the relative maintenance of these parameters in the old female rat.

Parental care in the buffy-tufted-ear marmoset (Callithrix aurita) in wild and captive groups

Studies on cooperative care of offspring in callitrichid primates are biased in favor of observations in captivity. In the wild, however, individuals have to deal with environmental pressures, which may influence their social behavior. We compared the individual effort attributed to parental care offered by members of a wild group (couple, plus a subadult helper) and two captive groups (A: couple, plus an subadult helper, B: couple, plus four adult helpers) of the buffy-tufted-ear marmoset, Callithrix aurita, from weeks 1-12 after the infants' birth. The carrier (breeding male and female or helper) and the infant's feeding (food sharing and foraging for food) were recorded. Up to week four, while the wild breeding pair shared infant carrying at similar proportions, the male from captive group A carried 100 percent of the time. Adult helpers from group B were the main carriers. Carrying behavior extended up to week 12 only in the wild group. Food provisioning to the infant was observed earlier in the groups wild and A, but general proportion of feeding records was lower in the wild than in captivity. Energetic cost of travelling and searching for food may be associated with equal division of carrying behavior by the wild breeding pair. Higher proportions of carrying in the groups wild and B may have delayed the development of the infants' motor skills required in foraging. Our data agree with previous studies: the father's lower investment in carrying when adult helpers are present and lower contribution of subadult non-reproductive members

Anti-inflammatory, analgesic activity and acute toxicity of Sida cordifolia L. (Malva-branca).

Sida cordifolia L. (Malvaceae) is used in folk medicine for the treatment of inflammation of the oral mucosa, blenorrhea, asthmatic bronchitis and nasal congestion. The anti-inflammatory, analgesic effects and acute toxicity of an aqueous extract of S. cordifolia were evaluated in animal models. The extract was prepared using leaves collected before the flowering period. The aqueous extract (AE) showed a significant inhibition of carrageenin-induced rat paw edema at a dose of 400 mg/kg administered orally, but did not block the edema induced by arachidonic acid. The AE also increased the latency period for mice in the hot plate test, and inhibited the number of writhes produced by acetic acid at the oral dose of 400 mg/kg. The aqueous extract of S. cordifolia showed low acute toxicity in mice.

Parental care in the buffy-tufted-ear marmoset (Callithrix aurita) in wild and captive groups.

Studies on cooperative care of offspring in callitrichid primates are biased in favor of observations in captivity. In the wild, however, individuals have to deal with environmental pressures, which may influence their social behavior. We compared the individual effort attributed to parental care offered by members of a wild group (couple, plus a subadult helper) and two captive groups (A: couple, plus an subadult helper, B: couple, plus four adult helpers) of the buffy-tufted-ear marmoset, Callithrix aurita, from weeks 1-12 after the infants' birth. The carrier (breeding male and female or helper) and the infant's feeding (food sharing and foraging for food) were recorded. Up to week four, while the wild breeding pair shared infant carrying at similar proportions, the male from captive group A carried 100% of the time. Adult helpers from group B were the main carriers. Carrying behavior extended up to week 12 only in the wild group. Food provisioning to the infant was observed earlier in the groups wild and A, but general proportion of feeding records was lower in the wild than in captivity. Energetic cost of travelling and searching for food may be associated with equal division of carrying behavior by the wild breeding pair. Higher proportions of carrying in the groups wild and B may have delayed the development of the infants' motor skills required in foraging. Our data agree with previous studies: the father's lower investment in carrying when adult helpers are present and lower contribution of subadult non-reproductive members.

Interaction between substance P and gastrin-releasing peptide on thyrotropin secretion by rat pituitary in vitro

The effect of substance P (SP) on thyrotropin (TSH) secretion is controversial. In this study we evaluated the effect of SP on TSH secretion by hemipituitaries of 3-month-old Wistar rats in vitro and its interaction with gastrin-releasing peptide (GRP) at equimolar concentrations (1 µM and 10 µM). TSH release was measured under basal conditions and 30 min after incubation in the absence or presence of SP, GRP or both peptides. Pituitary TSH content was also measured in the pituitary homogenate after incubation. SP at both concentrations caused a significant (P<0.05) increase in TSH secretion compared with all other groups, which was approximately 60 percent (1 µM) and 85 percent (10 µM) higher than that of the control group (23.3 + or - 3.0 ng/ml). GRP at the lower concentration did not produce a statistically significant change in TSH secretion, whereas at the concentration of 10 µM it produced a 50 percent reduction in TSH. GRP co-incubated with substance P completely blocked the stimulatory effect of SP at both concentrations. Pituitary TSH content decreased in the SP-treated group compared to controls (0.75 + or - 0.03 µg/hemipituitary) at the same proportion as the increase in TSH secretion, and this effect was also blocked when GRP and SP were co-incubated. In conclusion, in an in vitro system, SP increased TSH secretion acting directly at the pituitary level and this effect was blocked by GRP, suggesting that GRP is more potent than SP on TSH secretion, and that this inhibitory effect could be the predominant effect in vivo

Interaction between substance P and gastrin-releasing peptide on thyrotropin secretion by rat pituitary in vitro.

The effect of substance P (SP) on thyrotropin (TSH) secretion is controversial. In this study we evaluated the effect of SP on TSH secretion by hemipituitaries of 3-month-old Wistar rats in vitro and its interaction with gastrin-releasing peptide (GRP) at equimolar concentrations (1 microM and 10 microM). TSH release was measured under basal conditions and 30 min after incubation in the absence or presence of SP, GRP or both peptides. Pituitary TSH content was also measured in the pituitary homogenate after incubation. SP at both concentrations caused a significant (P<0.05) increase in TSH secretion compared with all other groups, which was approximately 60% (1 microM) and 85% (10 microM) higher than that of the control group (23.3 +/- 3.0 ng/ml). GRP at the lower concentration did not produce a statistically significant change in TSH secretion, whereas at the concentration of 10 microM it produced a 50% reduction in TSH. GRP co-incubated with substance P completely blocked the stimulatory effect of SP at both concentrations. Pituitary TSH content decreased in the SP-treated group compared to controls (0.75 +/- 0.03 microg/hemipituitary) at the same proportion as the increase in TSH secretion, and this effect was also blocked when GRP and SP were co-incubated. In conclusion, in an in vitro system, SP increased TSH secretion acting directly at the pituitary level and this effect was blocked by GRP, suggesting that GRP is more potent than SP on TSH secretion, and that this inhibitory effect could be the predominant effect in vivo.