Purification and analysis of protein synthetic initiation factors from Volvox Carteri

Volvox carteri, a multi-celled green algae, can grow synchronously given a sixteen hour light period followed by an eight hour dark period, a cycle which is repeated for a 48 hour growth cycle total. Near the end of each light period, reproductive cells divide rapidly resulting in the differentiation of ceIls. When the dark period begins, this differentiation stops and the cells remain dormant with little protein synthesis or differentiation occurring. Immediately after the lights come back on, however, the cells again undergo rapid protein synthesis and complete their differentiation. Previous studies have concluded that Volvox carteri discontinue protein synthesis during the dark phase due to regulation at the translational level and not the transcriptional level. Therefore, the inhibition of protein synthesis does not lie in the transfer of the protein coding sequence from DNA to mRNA, but rather in the transfer of this information from the mRNA to the ribosomes. My research examined this translational regulation to determine the factor(s) causing the discontinuation of protein synthesis during the dark phase. Evidence from other research further suggests that the control of translation lies in the initiation step rather than the elongation step. Eukaryotic initiation factors aid in the binding of the ribosomal subunits to the mRNA to initiate protein synthesis. It is known that initiation factors can be modified by phosphorylation, regulating their activity. Therefore, my study focused upon isolating some of these initiation factors in order to determine whether or not such modifications are responsible for the inhibition of dark phase protein synthesis in Volvox carteri.

A Light, investimento estrangeiro no Brasil: uma luz sobre o ciclo privado-público-privado em 80 anos pela análise de taxa de retorno

A Brazilian Traction, Light and Power Company ("Light"), formada por empreendedores canadenses em 1899, operou por 80 anos praticamente toda a infraestrutura (bondes, luz, telefones, gás) do eixo Rio-São Paulo. A empresa passou por vários ciclos políticos, desde sua fundação até sua estatização em 1979. Durante este período de 80 anos, a infra-estrutura nacional, inicialmente privada, foi gradativamente passando para as mãos do Estado. O setor voltaria a ser privado a partir dos anos 90, configurando o ciclo privado-público-privado, similar ao ocorrido nos países mais desenvolvidos. A Light, símbolo maior do capital estrangeiro até os anos 50, foi inicialmente bem recebida no país, posto que seu desenvolvimento era simbiótico, causa e conseqüência, ao desenvolvimento industrial. Dos anos 20 em diante, crescem os debates econômicos ou ideológicos quanto ao papel do capital privado estrangeiro no desenvolvimento nacional, vis-a-vis a opção do setor público como ator principal. Sempre permaneceu sob névoa quais teriam sido os lucros da Light no Brasil, e se esses seriam excessivos, acima do razoável. Outra questão recorrente se refere até que ponto os congelamentos de tarifas teriam contribuido para a crise de oferta de infra-estrutura. Através de um trabalho de pesquisa em fontes primárias, esta dissertação procura reconstituir a história da Light, sob um foco de Taxa de Retorno sob o capital investido. Foi reconstruída a história financeira da Light no Brasil, a partir da qual calculou-se, para vários períodos e para os seus 80 anos de vida, os retornos obtidos pelos acionistas da empresa. A partir dos resultados obtidos, e utilizando-se de benchmarks comparativos, foi possível mostrar que: i) ao contrário da crença vigente à época, o retorno obtido pelo maior investidor estrangeiro no setor de infra-estrutura do Brasil do Séc. XX, se mostrou bem abaixo do mínimo aceitável, e ii) o represamento de tarifas, por várias décadas, foi de fato determinante para o subdesenvolvimento do setor de infra-estrutura no Brasil.

Investigação do papel modulador do Haloperidol sobre os níveis de proteínas relacionadas à plasticidade e preferência por objetos novos em camudongos

Dopamine (DA) is known to regulate both sleep and memory formations, while sleep plays a critical role in the consolidation of different types of memories. We believe that pharmacological manipulation of dopaminergic pathways might disrupt the sleep-wake cycle, leading to mnemonic deficits, which can be observed in both behavioral and molecular levels. Therefore, here we investigated how systemic injections of haloperidol (0.3 mg/kg), immediately after training in dark and light periods, affects learning assessed in the novel object preference test (NOPT) in mice. We also investigated the hippocampal levels of the plasticity-related proteins Zif-268, brain-derived neurotrophic factor (BDNF) and phosphorylated Ca2+/calmodulin-dependent protein kinases II (CaMKII-P) in non-exposed (naïve), vehicle-injected controls and haloperidol-treated mice at 3, 6 and 12 hours after training in the light period. Haloperidol administration during the light period led to a subsequent impairment in the NOPT. In contrast, preference was not observed during the dark period neither in mice injected with haloperidol, nor in vehicle-injected animals. A partial increase of CaMKII-P in the hippocampal field CA3 of vehicle-injected mice was detected at 3h. Haloperidol-treated mice showed a significant decrease in the dentate gyrus of CaMKII-P levels at 3, 6 and 12h; of Zif-268 levels at 6h, and of BDNF levels at 12h after training. Since the mnemonic effects of haloperidol were only observed in the light period when animals tend to sleep, we suggest that these effects are related to REM sleep disruption after haloperidol injection

Can native vegetation recover after slash pine cultivation in the Brazilian Savanna?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relação entre padrão comportamental, estágios do ciclo de muda e atividade de enzimas digestivas proteolíticas em juvenis do camarão marinho Litopenaeus vannamei (Crustacea: Penaeidae)

Shrimp farming in Brazil is a consolidated activity, having brought economical and social gains to several states with the largest production concentrated in the northeast. This fact is also reflected in higher feed intake, necessitating a more efficient feed management. Currently, management techniques already foresee food loss due to molting. In this sense, studies relating shrimp s digestive physiology, molting physiology and behavioral response of shrimp feed can optimize the feed management. Thus, our study aimed to evaluate the behavioral response of the marine shrimp L. vannamei (Crustacea: Penaeidae) in accordance with the stages of moulting cycle and feeding schedules based on higher or lower activity of proteolytic digestive enzymes; also, to investigate the influence of feeding schedule on hepatosomatic index and non-specific and specific protease activity (trypsin). Experiments were carried out at the Laboratory of Shrimp Behavioral Studies at UFRN in partnership with the Laboratory of Enzimology UFPE. Juveniles of L. vannamei weighting 5.25 g (+ 0.25 g) were kept in aquaria at a density of 33 shrimp m -2. In the first experiment, shrimp were fed in the light phase or in the dark phase for 8 days; in the ninth day, the animals were observed for 15 minutes every hour during the 12 hours of each phase of the photoperiod. We recorded the frequency of inactivity, exploration, food intake, burrowing, swimming and crawling behavior. At the end of the 12th observation session, the shrimp were sacrified and classified by the method of setogenesis in the molt cycle stages A, B, C, D0, D1, D2 or D3. We found that the shrimp in A stage show high levels of inactivity. Moreover, the frequency of food intake was very low. The shrimp in D3 stage also had low food intake and high inactivity associated with elevated frequencies of burrowing. In the second experiment, shrimp were kept in physiological acclimation to experimental conditions for 28 days, distributed in 12 treatments in the light phase and 12 treatments in the dark phase. In the end, the animals were sacrified and dissected to assess non-specific and specific protease activity (trypsin) activity. In general, these parameters did not vary among animals fed in the light phase and those fed in the dark phase. However, significant differences were found in the activity of specific and nonspecific proteases in relation to food treatment. In the light phase, the major proteolytic activities converged to 10 hours after the start of the light phase, while the lowest activities converged to 6 hours after the beginning of this phase. In the dark phase, the highest enzyme activity converged to 12 hours after the onset of phase, while the lowest activities converged to 3 hours after the onset of phase. In the third experiment, we sought to evaluate the behavioral responses of shrimp in relation to dietary treatments based on higher or lower activity of proteolytic enzymes, considering the results of the second experiment. The behavioral categories observed were the same as the ones in the first experiment, with observations of 30 minutes (15min before and 15min after food supply). We found variation in behavioral responses as a function of the treatments, with greater intake of food in shrimp fed during the period of greatest activity of proteolytic enzymes, in the light phase. Thus we see that periodic events associated with the shrimp s physiology interfere in their behavioral responses, revealing situations that are more adjustable to the provision of food, and consequently optimizing feeding management

Estudo da organização funcional do sistema circadiano por meio de ferramentas computacionais e matemáticas

Circadian rhythms are variations in physiological processes that help living beings to adapt to environmental cycles. These rhythms are generated and are synchronized to the dark light cycle through the suprachiasmatic nucleus. The integrity of circadian rhythmicity has great implication on human health. Currently it is known that disturbances in circadian rhythms are related to some problems of today such as obesity, propensity for certain types of cancer and mental disorders for example. The circadian rhythmicity can be studied through experiments with animal models and in humans directly. In this work we use computational models to gather experimental results from the literature and explain the results of our laboratory. Another focus of this study was to analyze data rhythms of activity and rest obtained experimentally. Here we made a review on the use of variables used to analyze these data and finally propose an update on how to calculate these variables. Our models were able to reproduce the main experimental results in the literature and provided explanations for the results of experiments performed in our laboratory. The new variables used to analyze the rhythm of activity and rest in humans were more efficient to describe the fragmentation and synchronization of this rhythm. Therefore, the work contributed improving existing tools for the study of circadian rhythms in mammals

Caracterização do ritmo de atividade/repouso do Mocó (Kerodon Rupestris) em fotoperíodo artificial

Kerodon rupestris (rock cavy, mocó) is an endemic caviidae of Brazilian northeast that inhabits rocky places in the semi arid region. The aim of this study was to characterize the activity/rest rhythm of the rock cavy under 12:12 h LD cycle and continuous light. In the first stage, seven animals were submitted to two light intensities (LD; 250:0 lux and 400:0 lux; 40 days each intensity). In the second stage four males were kept for 40 days in LD (470:<1 lux), for 18 days in LL 470 lux (LL470) and for 23 days in red dim light below 1 lux (LL<1). In the third stage three males were initially kept in LD 12:12 h (450:<1 lux) and after that in LL with gradual increase in light intensity each 21 days (<1 lux LL<1; 10 lux-LL10; 160 lux LL160; 450 lux LL450). In the fourth stage it was analyzed the motor activity of 16 animals in the first 10 days in LD. Motor activity was continuously recorded by passive infrared movement sensors connected to a computer and totaled in 5 min bins. The activity showed circadian and ultradian rhythms and activity peaks at phase transitions. The activity and the rest occurred in the light as well as in the dark phase, with activity mean greater in the light phase for most of the animals. The light intensity influenced the activity/rest rhythm in the first three stages and in the first stage the activity in 400 lux increased in four animals and decreases in two. In the second stage, the tau for 3 animals in LL470 was greater than 24 h; in LL<1 it was greater than 24 h for one and lower for two. In the third stage the tau decreased with the light intensity increase for animal 8. During the first days in the experimental room, the animals did not synchronize to the LD cycle with activity and rest occurring in both phases. The results indicate that the activity/rest rhythm of Kerodon rupestris can be affected by light intensity and that the synchronization to the LD cycle results from entrainment as well as masking probably as a consequence of the action of two or more oscillators with low coupling strength

Comportamento do camarão de água doce macrobrachium rosenbergii (De Man, 1879) em cultivos misto e monossexo

Understanding the behavioral activities of freshwater shrimp in captivity is of paramount importance for the appropriate management of the species. In Brazil, the shrimp Macrobrachium rosenbergii is currently the most widely used species in the freshwater shrimp culture due to its high potential for cultivation and good market acceptance. Thus, the present study aimed to describe and characterize the behavioral activities of M. rosenbergii in monosex and in mixed (male and female) (manuscript 1, 2 and 3) populations and the growth performance of this species in restrictive feeding conditions and in different feeding management (manuscript 4 and 5, respectively) . Juvenile and adult shrimps were collected from ponds of the Aquaculture Station - Unidade Especializada em Ciências Agrárias - Universidade Federal do Rio Grande do Norte (UFRN), Macaíba/RN and then transferred to the Laboratório de Estudos do Comportamento do Camarão LECC (Laboratory for Shrimp Behavioral Studies) of the Universidade Federal do Rio Grande do Norte (UFRN). For each treatment , eight aquaria of 250 L (50 cm x 50 cm x 100 cm) were used in a closed recirculating water system with artificial lighting, constant aeration , continuous filtration through a biochemical and biological filter (canister filter), and fine sand as substrate . The water quality was monitored daily. The lab consisted of two rooms with artificial lighting system , controlled by a timer with dark / light cycle of 12:12 h . In manuscript 1, the behavioral categories of the species were presented through an ethogram, which described 31 behaviors, subdivided into general and agonistic behaviors. Manuscript 2 compared the behavioral profile of shrimps in male and in female monosex and mixed populations over 24 hours in laboratory. In three types (mixed, male monosex and female monosex) of populations during the light and dark phases of the 24 hour cycle, the shrimps showed higher occurrence of cleaning behavior. Manuscript 3 examined the influence of the color of the shelter on the frequency of its use and behavioral activities of shrimp in mixed, in male monosex and in female monosex populations over 24 hours. We observed that the shrimp M. rosenbergii burrow more frequently during the light phase in male monosex and mixed populations; they also tend to choose the black shelters. Female monosex populations tend to use red and orange shelters. In manuscript 4, we evaluated in laboratory the behavioral activities and growth performance of juvenile shrimps under food restriction. We observed that a mild food restriction may be used since there is no loss concerning the growth of the animals; feeding management on alternate days , compared to daily management can be financially productive both reducing labor costs and reducing the amount of feed used . Manuscript 5 evaluated the behavior of shrimps in monosex and in mixed populations, as well as the latency of reach the food according to feed offer (tray or food dispersal) . Our results indicate that animals adjust to both types of feed offer food dispersal as much as tray, but they spend more time to reach the feed when it is offered in trays (feeders). Comparing culture types (mixed, male monosex and female monosex), the latency to reach the food was lower for female monosex population. The data obtained in this study demonstrate the importance of identifying different pressures and environmental stimuli on the behavioral responses of this species. This knowledge would support management improvement to optimize the levels of animals‟ welfare, resulting in a better zootecnical performance

Distribuição diária das atividades comportamentais dos camarões marinhos Farfantepenaeus subtilis (Pérez Farfante, 1967) e Litopenaeus schmitti (Burkenroad, 1938) em condições laboratoriais

Marine aquaculture has developed in the last decades all over the world, especially related to shrimp management. In Brazil, the introduction of the species Litopenaeus vannamei has contributed to the success of the activity, even if there are problems associated with the management of a exotic species, such as new diseases and ecological pressure on native species. It has been emphasized the need of research for developing new methodology that will allow native species management, being the most important Farfantepenaeus subtilis and Litopenaeus schmitti. Most knowledge obtained from research with those species has generally used a technical approach and mainly focused feeding process. There are no specific behavioral data on their activity pattern which should be of great importance for the use of native species on commercial culture farms. So, it was our objective to study and compare the daily distribution of behavioral activities of the marine shrimp species Litopenaeus schmitti and Farfantepenaeus subtilis. Forty animals of each species, 5 individuals per aquarium, were maintained in aquaria containing 200L of sea water under continuous aeration and filtration. They were marked individually and were observed by the instantaneous focal time sampling, along 10 continuous days, in 6 daily 15 min observation windows, every two hour. In each window, behaviors and location position of the animals in the aquarium were registered at 1 min intervals. Food was offered 3 times a day, representing 10% of each aquarium biomass. Aquaria were maintained in artificial photoperiod, 12hour light/l2 hour dark, 4 aquaria in light cycle equivalent to the environmental one (light from 06:00 to 17:59 h and dark from 18:00 to 05:59 h) and the other 4 in the reverse light cycle (light from 18:00 to 05:59 h and dark from 06:00 to 17:59 h) to allow sequential behavioral observation in both phases of the 24 hour cycle. There was a clear distinction between the distribution of behavioral activities of F. subtilis and L. schmitti in the two phases. The activity pattern of Farfantepenaeus subtilis demonstrates that species has prominently night habits and a burying pattern during the light cycle. Exploration, inactivity and swimming were the most common activities. The behavioral pattern of Litopenaeus schmitti indicates that species is active along both phases of the light cycle, and the most evident behaviors were exploration, inactivity and swimming

Comportamento alimentar do camarão marinho farfantenaeus subtilis em condições laboratoriais

Shrimp culture represents an important activity to brazilian economy. The northeastern region has presented high levels of production because of its climatic conditions. An important factor for the activity´s major development is related to the introduction of the species Litopenaeus vannamei. The use of an exotic species can disturb the ecosystem. In the last decades, L. vannamei has been the only species cultivated in Brazilian farms, there not being an alternative species for shrimp culture. So, there is an urgent need to developing new studies with the native species, which might represent an alternative concerning shrimp production, with emphasis on Farfantepenaeus subtilis. Another important aspect related to the activity is feeding management, once it is quite usual that feed offer on the pond does not take into account either the species´ physiology and behavior or the influence of environmental variables, such as light cycle and substrate. That knowledge may optimize management and so reduce the impact of effluents in the environment. This study´s objective was characterizing feeding behavior of F. subtilis in laboratory. For that, an ethogram was developed, using 20 wild animals which were observed through ad libitum and all occurrences methods. Two experiments were developed in order to register feeding behavior on different substrates, along 15 days, each. In the first experiment, 40 animals were distributed in eight aquaria, half being observed during the light phase of the 24 hour cycle and the other half in the dark phase, both in halimeda substrate. In the second experiment, 20 animals were distributed in four aquaria, under similar conditions as the previous ones, but in sand substrate. In both experiments, animals were observed respectively one, four, seven and ten hours after the beginning of the phase, for light phase, for the dark phase, in ten minute observation windows, before and immediately after feed offer. The following behaviors were registered: feed ingestion, ingestion of other items, inactivity, exploration, vertical exploration, swimming, crawling, digging, burrowing, and moving by the animals. Observation windows after feed offer also included latency to reach the tray and to ingest feed. Nineteen behaviors were described for the species. F. subtilis presented more behavioral activities in halimeda substrate even in the light phase, while burrowing was predominant in sand substrate. In both substrates, moving, crawling and exploration were more frequent after feed offer, but inactivity and burrowing were more frequent before that. Feed ingestion was more frequent in halimeda, both in light and dark phases. Weight gain was also more prominent in that substrate. In sand substrtate, ingestion was more frequent in the dark phase, which suggests that higher granulometry facilitates feed ingestion in F. subtilis juveniles. Our results demonstrate the importance of studies for the better knowledge of the species, specially its response to environmental stimuli, in order to improve animal management

In Vitro Study of the influence of the pigments of three colored gels over the light distribution of visible light by digital images

Nowadays the real contribution of light on the acceleration of the chemical reaction for the dental bleaching is under incredulity, mostly because the real mechanisms of its contribution still are obscure. Objectives: Determine the influence of pigment of three colored bleaching gels in the light distribution and absorption in the teeth, to accomplish that, we have used in this experiment bovine teeth and three colored bleaching gels. It is well Known that the dark molecules absorb light and increase the local temperature upraising the bleaching rate, these molecules are located in the interface between the enamel and dentin. Methods: This study was realized using an argon laser with 455nm with 150mW of intensity and a LED with the same characteristics, three colored gels (green, blue and red) and to realize the capture of the digital images it was used a CCD camera connected to a PC. The images were processed in a mathematical environment (MATHLAB, R12 (R)). Results: The obtained results show that the color of the bleaching gel influences significantly the absorption of light in the specific sites of the teeth. Conclusions: This poor absorption can be one of the major factors involved with the incredulity of the light contribution on the process that can be observed in the literature nowadays.

Scarification, temperature and light in germination of Senna occidentalis seed (Caesalpinaceae)

The purpose of the present work was to study various aspects of the germination of seeds of Senna occidentalis Link, which had presented promising results in biological activity against the etiological agent of malaria. These aspects were dormancy, temperatures of germination and photoblastic response. In the dormancy studies, the treatments used were: unscarified seed (control); tegument puncture with sharp point; and scarification with sand-paper and immersion in concentrated sulfuric acid during 5, 10, 15 and 20 minutes. For the study of temperature and photoblast, the seeds were immersed in sulfuric acid for 20 minutes, submitted to temperatures of 10 to 45degreesC, at intervals of 5degreesC, both under light and in the dark. The seeds presented dormancy related to tegument, the best treatments for breaking dormancy were immersion in sulfuric acid for 15 and 20 minutes. At temperatures 25 and 30degreesC, the best results of percentage and index of velocity of germination were observed, at which the seeds behaved as neutral photoblastic; there was no germination at 10 or at 45degreesC.

The role of the parenchyma sheath and PCD during the development of oil cavities in Pterodon pubescens (Leguminosae-Papilionoideae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of light quality on germination and initial growth of canephori seedlings Peltophorum dubium (Sprenge) Taub.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Interaction of temperature and light on seed germination in Tecoma stans L. Juss. ex Kunth (Bignoniaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)