Differential Habituation of Male Betta Splendens to Qualitatively Different Stimuli

Habituation is a learning mechanism that functions to decrease the amount of energy and attention focused on a certain stimuli. Male Siamese Fighting Fish, Betta splendens, are territorial animals that defend their territories using a number of aggressive displays. Male Bettas have previously shown the ability to habituate to the presence of a conspecific male when visually exposed to each other. Due to the costly nature of many of the male Betta’s displays, I hypothesized that male Bettas should differentially habituate to qualitatively different stimuli. I presented each of three groups of male Betta splendens with a different stimulus, each presenting a different level of interactivity. I predicted that the Bettas would be more likely to habituate to a less interactive stimulus than a more interactive one. No significant habituation was observed in any of the groups and no significant differences in latency to display or length of display between all three groups were observed. However, overall data trends suggest that habituation was indeed occurring and that the three different stimuli elicited different levels of display. The limited amount of visual exposure to the stimuli in this experiment might account for why results were insignificant.

Digestibilidade de alimentos protéicos e energéticos para fêmeas de beta

Foram avaliados os coeficientes de digestibilidade aparente de MS, PB, energia bruta (EB) e EE de alimentos protéicos (farelo de soja e farinha de peixe) e energéticos (fubá de milho e farelo de trigo) para beta (Betta splendens). Fêmeas adultas foram alojadas em gaiolas e mantidas em dois aquários de fibra de vidro (30 peixes/aquário) para alimentação e dois para coleta de fezes, ambos de formato cônico e com capacidade para 30 L. Os resultados dos coeficientes de digestibilidade aparente de MS, PB, EB e EE foram, respectivamente, de 69,43; 72,52; 67,91 e 55,50% para farelo de soja; 60,67; 51,15; 75,55 e 58,26% para farinha de peixe; 63,88; 87,16; 77,61 e 50,40% para fubá de milho; e 61,06; 93,37; 58,17 e 65,51% para farelo de trigo. Os resultados obtidos neste estudo permitem otimizar a formulação de dietas práticas balanceadas, economicamente viáveis para a espécie.

O romance em baixo d’água: tipos comportamentais e escolha de parceiros em Betta splendens

Cada indivíduo apresenta uma respostas comportamental diferente diante de um desafio ambiental, muitas vezes mesmo quando comparado a outro indivíduo da mesma espécie, sexo e idade, essas diferenças são chamadas tipos comportamentais e quando consistentes ao longo do tempo caracterizam uma síndrome comportamental ou personalidade animal. Evidências apontam que a personalidade animal pode interferir na aptidão reprodutiva do indivíduo. Tendo isso em vista, no presente estudo machos e fêmeas adultos de Betta splendens foram observados em três contextos (exploratório, social e avaliação de risco), para identificar a existência de tipos comportamentais e diferenças entre os sexos nos tipos comportamentais nessa espécie. Os indivíduos foram classificados em três níveis em cada contexto: contexto social (social; intermediário e não-social), contexto exploratório (explorador, intermediário e não-explorador) e avaliação de risco (bold, intermediário e shy). Após essa classificação, machos sociais e nãosociais, exploradores e não-exploradores de coloração vermelha e azul foram utilizados no experimento de escolha de parceiro pelas fêmeas. Nossos resultados apontam que a maioria dos indivíduos testados possui fenótipos intermediários para os três contextos avaliados, e uma minoria de machos e fêmeas apresentaram tipos comportamentais. E a análise de correlação mostra que machos e fêmeas se comportaram de modo diferente em relação aos contextos. No experimento de escolha de parceiro, os resultados mostram que os tipos comportamentais da fêmea e do macho influenciam no processo de escolha de parceiro e que, mesmo na presença de pistas visuais (coloração corporal dos machos), o tipo comportamental continua sendo importante no processo de escolha.

O romance em baixo d’água: tipos comportamentais e escolha de parceiros em Betta splendens

Cada indivíduo apresenta uma respostas comportamental diferente diante de um desafio ambiental, muitas vezes mesmo quando comparado a outro indivíduo da mesma espécie, sexo e idade, essas diferenças são chamadas tipos comportamentais e quando consistentes ao longo do tempo caracterizam uma síndrome comportamental ou personalidade animal. Evidências apontam que a personalidade animal pode interferir na aptidão reprodutiva do indivíduo. Tendo isso em vista, no presente estudo machos e fêmeas adultos de Betta splendens foram observados em três contextos (exploratório, social e avaliação de risco), para identificar a existência de tipos comportamentais e diferenças entre os sexos nos tipos comportamentais nessa espécie. Os indivíduos foram classificados em três níveis em cada contexto: contexto social (social; intermediário e não-social), contexto exploratório (explorador, intermediário e não-explorador) e avaliação de risco (bold, intermediário e shy). Após essa classificação, machos sociais e nãosociais, exploradores e não-exploradores de coloração vermelha e azul foram utilizados no experimento de escolha de parceiro pelas fêmeas. Nossos resultados apontam que a maioria dos indivíduos testados possui fenótipos intermediários para os três contextos avaliados, e uma minoria de machos e fêmeas apresentaram tipos comportamentais. E a análise de correlação mostra que machos e fêmeas se comportaram de modo diferente em relação aos contextos. No experimento de escolha de parceiro, os resultados mostram que os tipos comportamentais da fêmea e do macho influenciam no processo de escolha de parceiro e que, mesmo na presença de pistas visuais (coloração corporal dos machos), o tipo comportamental continua sendo importante no processo de escolha.

Vitronectin modulates human mesenchymal stem cell response to insulin-like growth factor-I and transforming growth factor beta 1 in a serum-free environment

The use of animal sera for the culture of therapeutically important cells impedes the clinical use of the cells. We sought to characterize the functional response of human mesenchymal stem cells (hMSCs) to specific proteins known to exist in bone tissue with a view to eliminating the requirement of animal sera. Insulin-like growth factor-I (IGF-I), via IGF binding protein-3 or -5 (IGFBP-3 or -5) and transforming growth factor-beta 1 (TGF-beta(1)) are known to associate with the extracellular matrix (ECM) protein vitronectin (VN) and elicit functional responses in a range of cell types in vitro. We found that specific combinations of VN, IGFBP-3 or -5, and IGF-I or TGF-beta(1) could stimulate initial functional responses in hMSCs and that IGF-I or TGF-beta(1) induced hMSC aggregation, but VN concentration modulated this effect. We speculated that the aggregation effect may be due to endogenous protease activity, although we found that neither IGF-I nor TGF-beta(1) affected the functional expression of matrix metalloprotease-2 or -9, two common proteases expressed by hMSCs. In summary, combinations of the ECM and growth factors described herein may form the basis of defined cell culture media supplements, although the effect of endogenous protease expression on the function of such proteins requires investigation.

A functional screen identifies lateral transfer of beta-glucuronidase (gus) from bacteria to fungi

Lateral gene transfer (LGT) from prokaryotes to microbial eukaryotes is usually detected by chance through genome-sequencing projects. Here, we explore a different, hypothesis-driven approach. We show that the fitness advantage associated with the transferred gene, typically invoked only in retrospect, can be used to design a functional screen capable of identifying postulated LGT cases. We hypothesized that beta-glucuronidase (gus) genes may be prone to LGT from bacteria to fungi (thought to lack gus) because this would enable fungi to utilize glucuronides in vertebrate urine as a carbon source. Using an enrichment procedure based on a glucose-releasing glucuronide analog (cellobiouronic acid), we isolated two gus(+) ascomycete fungi from soils (Penicillium canescens and Scopulariopsis sp.). A phylogenetic analysis suggested that their gus genes, as well as the gus genes identified in genomic sequences of the ascomycetes Aspergillus nidulans and Gibberella zeae, had been introgressed laterally from high-GC gram(+) bacteria. Two such bacteria (Arthrobacter spp.), isolated together with the gus(+) fungi, appeared to be the descendants of a bacterial donor organism from which gus had been transferred to fungi. This scenario was independently supported by similar substrate affinities of the encoded beta-glucuronidases, the absence of introns from fungal gus genes, and the similarity between the signal peptide-encoding 5' extensions of some fungal gus genes and the Arthrobacter sequences upstream of gus. Differences in the sequences of the fungal 5' extensions suggested at least two separate introgression events after the divergence of the two main Euascomycete classes. We suggest that deposition of glucuronides on soils as a result of the colonization of land by vertebrates may have favored LGT of gus from bacteria to fungi in soils.

Good results for early treatment of clinically isolated syndrome prior to multiple sclerosis with interferon beta-1b and glatiramer

Background: The first sign of developing multiple sclerosis is a clinically isolated syndrome that resembles a multiple sclerosis relapse. Objective/methods: The objective was to review the clinical trials of two medicines in clinically isolated syndromes (interferon β and glatiramer acetate) to determine whether they prevent progression to definite multiple sclerosis. Results: In the BENEFIT trial, after 2 years, 45% of subjects in the placebo group developed clinically definite multiple sclerosis, and the rate was lower in the interferon β-1b group. Then all subjects were offered interferon β-1b, and the original interferon β-1b group became the early treatment group, and the placebo group became the delayed treatment group. After 5 years, the number of subjects with clinical definite multiple sclerosis remained lower in the early treatment than late treatment group. In the PreCISe trial, after 2 years, the time for 25% of the subjects to convert to definite multiple sclerosis was prolonged in the glatiramer group. Conclusions: Interferon β-1b and glatiramer acetate slow the progression of clinically isolated syndromes to definite multiple sclerosis. However, it is not known whether this early treatment slows the progression to the physical disabilities experienced in multiple sclerosis.

A two-compartment mechanochemical model of the roles of transforming growth factor-beta and tissue tension in dermal wound healing

The repair of dermal tissue is a complex process of interconnected phenomena, where cellular, chemical and mechanical aspects all play a role, both in an autocrine and in a paracrine fashion. Recent experimental results have shown that transforming growth factor-beta (TGF-beta) and tissue mechanics play roles in regulating cell proliferation, differentiation and the production of extracellular materials. We have developed a 1D mathematical model that considers the interaction between the cellular, chemical and mechanical phenomena, allowing the combination of TGF-beta and tissue stress to inform the activation of fibroblasts to myofibroblasts. Additionally, our model incorporates the observed feature of residual stress by considering the changing zero-stress state in the formulation for effective strain. Using this model, we predict that the continued presence of TGF-beta in dermal wounds will produce contractures due to the persistence of myofibroblasts; in contrast, early elimination of TGF-beta significantly reduces the myofibroblast numbers resulting in an increase in wound size. Similar results were obtained by varying the rate at which fibroblasts differentiate to myofibroblasts and by changing the myofibroblast apoptotic rate. Taken together, the implication is that elevated levels of myofibroblasts is the key factor behind wounds healing with excessive contraction, suggesting that clinical strategies which aim to reduce the myofibroblast density may reduce the appearance of contractures.