Tagetes minuta L. is a weedy herb that has been a rich source of fragrant oils, used as in the perfume and flavour industry. T. minuta achenes germinate erratically under field conditions. However, at the optimal germination temperature of 25 °C, 100 % germination is attained within 48 h of imbibition. The achenes are thermoinhibited at 35 °C. The aims of this project were to assess the role of cytokinins (CKs) in normal germination at 25 °C, and to investigate the factors that regulate thermoinhibition at 35 °C. CKs were extracted from achenes germinating at 25 °C at 0, 24; 48; 96 and 144 h after imbibition. Two different purification techniques were used, namely Dowex cation exchange resin followed by paper chromatography, or high performance liquid chromatography (HPLC). CK-like activity was tested with the soybean callus bioassay. With both techniques, a peak in CK-like activity appeared 24 h after imbibition, which coincides with the period during which most of the achenes germinated. For quantitative analysis, HPLC\mass spectrometry (MS) techniques were used. The isoprenoid CKs were far more abundant in T. minuta achenes than the aromatic CKs. cis-Zeatin (cZ) and its derivatives were the most abundant CKs. In total, 19 CK compounds were detected, including 4 free bases and a number of corresponding conjugates. Benzyladenine (BA) was the only aromatic CK detected. There was no common time at which active free base maximal concentrations were detected, suggesting that different CKs may have specific roles in the germination process, and thus peak at different times. This in turn suggests that germination is not a single process, but rather a correlative process involving a number of events, with specific CKs having specific roles relating to these correlative events. There is sufficient evidence obtained from both the soybean callus bioassay and HPLC/MS analysis to suggest that CKs have an active role in T. minuta germination. A decline in free BA during germination without corresponding conjugation, suggests that BA is actively used in early germination processes, possibly in the stimulation of DNA synthesis. Secondly, there was a distinct dihydrozeatin (DHZ) peak obtained at 24 h. Roughly 75 % of the achenes germinate between 16 and 26 h, thus it is likely that DHZ has an active role during the germination of T. minuta. Although CKs are probably not involved in the breaking of dormancy per se, the distinct peak in CK-like activity obtained in the bioassays, 24 h after imbibition, suggests that CKs have an active role in the germination of T. minuta. With respect to the regulation of thermoinhibition, a number of exogenous treatments were applied, including hormones [gibberellins (GA₄₊₇), abscisic acid (ABA), ethylene and a number of CKs], adenosine triphosphate (ATP) and incubation in 100 % oxygen. ABA was extracted from thermoinhibited and germinating achenes to assess the role of ABA in thermoinhibition and germination. While exogenous 0.1 mg L¯¹ GA₄₊₇ application slightly improved normal germination at 25°C, no treatments were effective in alleviating thermoinhbibition in T. minuta achenes. Thermoinhibition in T. minuta achenes may be under hormonal regulation, as there is strong evidence for the role of ABA in the maintenance of dormancy and thermoinhbition. High ABA levels were found in dry control samples. Additionally, exogenous ABA application inhibited normal germination, and the commencement of germination was accompanied by a decrease in endogenous ABA levels. A number of experiments relating to the imposition of thermoinhibition were carried out. Thermoinhibition appears to be very rapidly imposed. Germination is rapidly inhibited following shifting to higher thermoinhibitory temperatures, even after prolonged exposure to optimal germination temperatures. Results suggest active de novo biosynthesis of ABA in thermoinhibited achenes. Active biosynthesis of ABA during thermoinhibition suggests that this phytohormone is essential in the maintenance of thermoinhibition of T. minuta achenes. It thus appears that ABA is synthesized in the achenes in response to elevated temperatures that are unfavourable for germination to proceed. Unfavourable environmental conditions result in an achene-mediated inhibition of germination, which appears to be initiated and maintained by elevated levels of endogenous ABA. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

No description available.

When imbibed at their optimum germination temperature of 25°C, achenes of Tagetes minuta L. germinate over a period of approximately 48 h. At temperatures of between 35°C and 39°C, the achenes do not germinate but enter into a state of thermoinhibition. These supra-optimal conditions do not harm the achenes, however, and when the temperature is reduced below 35°C radicle emergence may be observed within 4 h. Achenes which have been thermoinhibited for periods of 24 h or more show "accelerated germination" which takes only 24 h, although the actual germination curve is identical to that of normally germinated achenes. This suggests that the achenes are metabolically active at thermoinhibitory temperatures and undergo most of the processes of normal germination, but that at some point any further development is halted, preventing radicle emergence. When the temperature is reduced, this block on germination is removed and since the achenes are already primed for germination, this occurs within a short time. An analysis of the proteins produced by germinating and thermoinhibited achenes was conducted using SDS-polyacrylamide gel electrophoresis (SDS-PAGE). This procedure was able to resolve approximately 40 different protein bands, but no differences were observed between thermoinhibited and germinating achenes. Two dimensional polyacrylamide gel electrophoresis (20-PAGE) was able to resolve approximately 200 individual polypeptides. The vast majority of polypeptides in T. minuta achenes are acidic, although the number of neutral to basic polypeptides increases as germination progresses. Ten polypeptides were identified which were specific to thermoinhibited achenes. These formed two distinct groups on the twodimensional gels. The larger group contained seven proteins, ranging in size from 22 kDa to 26.7 kDa and with isoelectric points of between 3.0 and 4.0. The smaller group contained three polypeptides with molecular weights of about 14 kDA and a pi of approximately 3.0. These polypeptides were all extremely specific to thermoinhibited achenes and declined rapidly when the incubation temperature was reduced, in a manner which correlated with an increase in the germinability of the achenes. Several characteristics of the expression of these polypeptides were similar to characteristics of embryo-dormancy in seeds where dormancy is thought to be actively imposed by the expression of specific dormancy-associated genes. This, along with the very tightly-regulated nature of these 10 polypeptides, suggests that thermoinhibition in T. minuta may be regulated through gene expression and that these ten polypeptides may represent the products of genes responsible for preventing radicle emergence at unfavourable temperatures. Since these polypeptides were only resolved using silver-staining and could not therefore be used for amino acid sequence analysis, this hypothesis was further investigated using differential display of mRNA to isolate genes which are expressed specifically in thermoinhibited achenes. A large number of cDNA fragments which were specific to either germinating or thermoinhibited achenes were identified and extracted from the differential display gels. Those cDNAs specific to the thermoinhibited achenes were taken for further analysis. Of the 62 fragments excised from the gels, 25 could be reamplified to generate single bands of the correct size on agarose gels. A further 22 cDNAs produced multiple bands, where one band was much brighter than the others and correlated with the size of the original fragment. Thirteen of the cDNAs which' generated single bands were cloned into the plasmid vector pGEM®-T Easy and transformed into either Escherichia coli JM109 or E. coli XL1-Blue. Recombinant colonies were identified using blue-white colour selection and the presence of the insert confirmed by colony blotting and restriction analysis. Three clones were chosen for each of the cDNAs. Reverse northern analysis confirmed that all 39 clones were specific to the mRNA pool of thermoinhibited achenes. High quality sequence data were obtained for 27 of the cDNA samples, the remainder appeared to have been degraded in transit. Alignment of the various sequences revealed that a total of 14 different sequences had been cloned, indicating that several of the bands isolated from the differential display gels contained multiple sequences. Electronic homology searches tentatively identified three of the sequences, whilst the remainder did not show significant homology to any known sequences. Of the cDNAs identified in this way, one may encode a plant transcription factor-like or nuclear RNA-binding protein whilst the other two may encode an RNase-L Inhibitor-like protein and a miraculin homologue. The potential roles of such genes in the imposition or maintenance of the thermoinhibited state are discussed. Although further research needs to be conducted to isolate full length cDNA sequences and to determine their exact expression patterns in germinating and thermoinhibited achenes, these results are consistent with the hypothesis that thermoinhibition in T. minuta achenes is under positive genetic control in a manner analogous to embryo dormancy. This thesis represents the first molecular study of thermoinhibition as well as the first report of active control over this phenomenon in any species. Since thermoinhibition, unlike dormancy, can be rapidly imposed and released under strictly controlled conditions without the need for any dormancy breaking treatment, T. minuta achenes represent an excellent model system for studies on the molecular control of seed germination. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2003.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-08-24T13:47:26Z No. of bitstreams: 1 Dissertaçao - Rommel Roberto Rojas Zamora.pdf: 13957441 bytes, checksum: 0166fb38e9a1d74cba0a955065ad3480 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-28T15:03:34Z (GMT) No. of bitstreams: 1 Dissertaçao - Rommel Roberto Rojas Zamora.pdf: 13957441 bytes, checksum: 0166fb38e9a1d74cba0a955065ad3480 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-28T15:09:04Z (GMT) No. of bitstreams: 1 Dissertaçao - Rommel Roberto Rojas Zamora.pdf: 13957441 bytes, checksum: 0166fb38e9a1d74cba0a955065ad3480 (MD5) / Made available in DSpace on 2015-08-28T15:09:04Z (GMT). No. of bitstreams: 1 Dissertaçao - Rommel Roberto Rojas Zamora.pdf: 13957441 bytes, checksum: 0166fb38e9a1d74cba0a955065ad3480 (MD5) Previous issue date: 2014-02-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Amazophrynella is a genus of the family Bufonidae. Actually the genus remains problematic taxonomically; the difficulty lays principally in the lack of diagnostic characters in the original description of A. minuta, the lack of molecular data and refined taxonomic comparison of individuals through its wide distribution. In this study a partial taxonomic revision of the genus Amazophrynella was performed; especially trying to reveal the evolutionary and biological diversity hidden in the A. minuta complex. The study was conducted integrating several sources of data: (1) phylogenetic, using the 16S rRNA; (2) morphometric, through the principal component analysis measures of organisms; (3) bioacoustics, by comparison of the advisement calls, and (4) morphological, by comparing meristic characters. Our results showed the existence of eight linages of Amazophrynella, four of which are known nominal species and the other four strains represent potential new species. The genetic distances showed a high divergence between all strains (higher than 4%). The comparison of the bioacustic data showed differences in frequency, note size, and number of pulses, while the principal component analysis indicated differences in size and shape between some phylogenetic lineages found. With the need to improve the taxonomy of the genus, A. minuta was redescribed based on topotypes collected at the type locality, generating new diagnostic characters and a more complete description of the species. Two phylogenetic linages of the genus found in this study were described morphologically; observing profound morphological differences between them. Based on our results, we suggest continuing studies of this genus. / Amazophrynella é um gênero da família Bufonidae que durante muito tempo não recebeu um tratamento taxonômico adequado; como por exemplo a espécie A. minuta; que provavelmente representa um complexo de espécies. No presente estudo foi realizada uma revisão da taxonômica e sistemática do gênero Amazophrynella; especialmente tentando revelar a diversidade biológica e evolutiva críptica no complexo A. minuta. O estudo foi realizado integrando dados filogenéticos, utilizando o gene 16S rRNA, morfométricos, através dos análises de componentes principais das medidas dos organismos, bioacústicos, pelo análises e comparação dos cantos de anúncio, e morfológicos, através da comparação de caracteres merísticos de todas as quatro espécies conhecidas do gênero. Nossos resultados filogenéticos mostraram a existência de oito linhagens de Amazophrynella; quatro dos quais são espécies nominais conhecidas e as outras quatro linhagens representam potenciais espécies novas. As distâncias genéticas mostraram uma alta divergência entre todas as linhagens (maior que 4%). A comparação dos cantos de anúncio mostraram diferenças nas frequências, tamanho da nota, e número de pulsos e as análises de componentes principais indicaram divergências na forma e tamanho entre algumas linhagens filogenéticas encontradas. Com a necessidade de melhorar a taxonomia do gênero, A. minuta foi redescrita com base em topótipos coletados na localidade tipo, gerando novos caracteres diagnósticos e uma descrição mais completa da espécie. Duas linhagens do gênero encontradas neste trabalho foram descritas morfologicamente; observando-se profundas diferenças morfológicas entre elas. Baseado em nossos resultados, sugerimos a continuidade dos estudos integrativos deste gênero.

Diploma thesis was aimed at studying of lipolytic activity of seven microorganisms, at which this activity was previously assumed or already confirmed. Theoretical part deals with the general characteristics of lipoyltic enzymes, specifics of microbial lipases and their industrial application, with an emphasis on food industry. Experimental part deals with the study of seven microorganisms and their lipolytic activity at the presence of a carbohydrate (glucose) or a lipid (canola oil) or both, as a source of carbon. For further testing were singled out Rhodotorula minuta nad Yarrowia lipolytica. This yeasts were subsequently tested for lipolytic aktivity at the presence of different vegetable oils (olive, sunflower, canola oil and waste cooking oil), nitrogen sources of organic and inorganic origin (urea, yeast extract, amonnium chloride, amonnium sulfate) and also a addition of detergent, which is commonly used in food industry or other food facilities.

Made available in DSpace on 2014-08-20T14:38:03Z (GMT). No. of bitstreams: 1 dissertacao_diane_bender_schiavon.pdf: 500386 bytes, checksum: 48fa2cd250b94f5f938cb28a34fe2107 (MD5) Previous issue date: 2011-02-24 / Bovine Mastitis is a disease that causes high damage to milk production. Phytotherapy is the basis of Tagetes minuta L. can be used for disease control agroecological production units. The study aimed to evaluate application of antiseptics from medicinal plant from the postmilking teat disinfection. The treatments consisted of commercial iodine with treatment 1, used as teat pos-dipping on the right side, and hydro alcoholic extract from leaves of Tagetes minuta and macerated seeds Linum usitatissimum L., both at 10%, used on teats left as pos-dipping, cows in a commercial production unit that had, in average of 60 milking animals during the experiment that lasted 12 weeks. The prevalence of subclinical mastitis was evaluated using the CMT test once a week. Test mug of dark background was done at all milking. Sample of milk from all quarters was collected weekly for the isolation and characterization of present microorganisms . The incidence of new intramammary infections was calculated using the number of infection-free days by quarters, counted by weekly analysis of milk from all quarters in blood agar culture, as the denominator and the number of new cases as the numerator, defined as culture positive by Staphylococcus spp. or Streptococcus spp. in Sampling of milk per room. The index was corrected to 1000 / 4 days. Exclusion criteria: infection with Streptococcus spp or Staphylococcus spp in early labor and up to two weeks after a collection microbiologically positive. Animals with two successive collections negative after a positive were considered cured and reintroduced in the counting of days without infection. The chi-square test was used to compare the frequency of events between treatments. The CMT's weekly prevalence ranged in group 1 between 29.5% and 17.1%, and group 2 from 29.7% to 19.6%, not significantly different in any of weeks. The incidence of positive cultures for Staphylococcus / Streptococcus was 3.93 and 6.96 / 1000 / 4 / day for Groups 1 and 2 respectively, p = 0.057. There were four cases of mastitis clinic during the experiment, two in each treatment. We concluded the use of plant extracts for the disinfection of teats pos-dipping can be useful systems for milk production agro ecological. / Mastite bovina é a doença que causa os maiores prejuízos na produção leiteira. A fitoterapia a base de Tagetes minuta pode ser utilizada para controle da enfermidade em unidades de produção agroecológicas. O trabalho objetivou avaliar a aplicação de anti-sépticos obtidos de planta medicinal na desinfecção de tetos pós-ordenha. Os tratamentos consistiram em iodo comercial como tratamento 1, utilizado como pós-dipping nos tetos do lado direito, e extrato hidroalcoolico de folhas de Tagetes minuta L. e macerado de sementes de Linum usitatissimum L., ambos à 10%, utilizados nos tetos esquerdos como pos-dipping de vacas em uma unidade de produção comercial que possuía, em média, 60 animais em ordenha durante o experimento que teve duração de 12 semanas. A prevalência de mastite sub-clínica foi avaliada utilizando o teste de CMT uma vez por semana. Teste da caneca de fundo escuro foi realizado em todas as ordenhas. Amostra de leite de todos os quartos foi coletada semanalmente para isolamento e caracterização dos microrganismos presentes. A incidência de novas infecções intra-mamárias foi calculada utilizando o número de dias livres de infecção por quarto, contados pela análise semanal de leite de todos os quartos em cultura de Agar sangue, como denominador, e o número de casos novos como numerador, definido como cultura positiva para Staphylococcus spp. ou Streptococcus spp. na amostragem do leite por quarto. O índice foi corrigido para 1000 quartos dia. Foram critérios de exclusão: infecção por Streptococcus spp ou Staphylococcus spp no início do trabalho e até duas semanas após uma coleta microbiologicamente positiva. Animais com duas coletas sucessivas negativas após uma positiva foram considerados curados e reintroduzidos na contagem de dias sem infecção. O teste do qui-quadrado foi utilizado para comparação das frequências dos eventos entre os tratamentos. A prevalência semanal do CMT variou no grupo 1 entre 29,5% e 17,1%, e no grupo 2 de 29,7% a 19,6%, não diferindo significativamente em nenhuma das semanas. A incidência de cultura positiva para Staphylococcus/Streptococcus foi de 3,93 e 6,96/1000 quartos/dia para os grupos 1 e 2 respectivamente, com p=0,057. Houve quatro casos de mastite clínica durante o experimento, dois em cada tratamento. Concluímos que o uso de extratos de plantas na desinfecção de tetos pós-ordenha pode ser útil aos sistemas de produção de leite agroecológico.

Dans le contexte du déclin général des zones humides temporaires méditerranéennes et du manque de connaissances à leur sujet en Tunisie, l'étude pluridisciplinaire et multiscalaire de leur structure et de leur fonctionnement a été entreprise dans les Mogods (Tunisie septentrionale). (1) A l'échelle régionale, l'inventaire et la typologie de ces milieux permettent d'en définir les enjeux conservatoires. Ces résultats montrent, d'une part l'intérêt biogéographique majeur de la zone d'étude, qui abrite des milieux rares et exceptionnels (zones tourbeuses, lacs semi-permanents, Garâa Sejenane), et d'autre part sa diversité spécifique et biocénotique reflétant l'hétérogénéité spatiale des conditions hydrologiques et pédologiques. (2) A l'échelle paysagère, l'étude des communautés végétales de trois mares temporaires permet de caractériser leur composition, leur structure et leur dynamique intra- et interannuelle, et de montrer l'influence majeure du pâturage. Les résultats obtenus mettent en évidence la nécessité d'une politique de gestion intégrant le maintien de l'hétérogénéité paysagère et le fonctionnement des zones humides en métapopulations. (3) A l'échelle locale, l'étude d'une espèce rare récemment découverte en Tunisie (Pilularia minuta) permet de caractériser pour la première fois la morphologie de ses organes reproducteurs, de mettre en évidence l'ancienneté de sa présence locale, de confirmer son caractère pionnier et d'évaluer sa dépendance vis-à-vis des conditions hydrologiques.Les résultats obtenus révèlent la diversité, la richesse et l'importance conservatoire des zones humides temporaires des Mogods, presque totalement méconnues et ignorées à l'heure actuelle. Ils mettent en évidence leur vulnérabilité face au développement socio-économique de la région, et soulignent l'urgence de développer une gestion conservatoire rationnelle, adaptée et durable, à différents niveaux d'organisation (région, commune, site). / In the context of the general decline of Mediterranean temporary wetlands and of the lack of knowledge about them in Tunisia, the pluridisciplinary and multi-scale study of their structure and functioning has been undertaken in the Mogods region (N. Tunisia). (1) At the regional scale, the survey and the typology of these habitats allow defining the conservatory stakes. These results show, first the major biogeographical interest of the study zone, which harbours rare and exceptional wetlands (peaty zones, semi-permanent lakes, Garâa Sejenane), and second its species and community diversity that reflects the spatial heterogeneity of hydrological conditions and soils. (2) At the landscape scale, the study of plant communities of three temporary pools allows characterising their composition, structure, and intra- and inter-year dynamics, and to show the major influence of grazing. The obtained results highlight the need for a management policy i ntegrating the conservation of the landscape heterogeneity and the pools' functioning in metapopulations. (3) At the local scale, the study of a rare species recently discovered in Tunisia (Pilularia minuta) allows characterising for the first time its reproduction organs, revealing its ancient local origin, confirming its pioneer character, and evaluating its dependence on hydrological conditions.The obtained results highlight the diversity, the richness and the conservatory importance of temporary wetlands of Mogods region, today almost completely unknown and ignored. They reveal their vulnerability to the socio-economical development of the region, and underline the urgency to develop a rational, adapted and sustainable conservatory management at different organisation levels (region, city, site).

O objetivo deste trabalho foi analisar a distribuição espaço-temporal de um representante da macrofauna de praias arenosas protegidas. As abordagens em diferentes escalas (mesoescala, microescala e escala temporal) foram empregadas. O gastrópode Olivella minuta, abundante na região entremarés da Baía do Araçá, foi utilizado para essas análises. Para o estudo em mesoescala, 16 estações foram demarcadas na região entremarés (julho/2009) e, em cada uma, foram coletadas 8 amostras biológicas e 3 de sedimento. Alguns fatores abióticos (carbonato de cálcio, matéria orgânica e coeficiente de seleção) influenciaram negativamente a abundância do gastrópode, enquanto relações entre O. minuta e as demais espécies da macrofauna não foram evidentes. Em microescala, em poças de maré (metros) e em \"ripple marks\" (centímetros) verificou-se que em escala de centímetros, o gastrópode foi mais abundante em locais com maior conteúdo de água no sedimento, enquanto em escala de metros a abundância não diferiu dentro e fora das poças. Em escala temporal, foram observadas flutuações mensais da densidade da população de O. minuta, com diminuição/ausência de indivíduos entre fevereiro e março, o que sugere a ocorrência de migrações e mortalidade. O presente trabalho mostrou que a distribuição desse gastrópode é influenciada por diferentes fatores que atuam em diferentes escalas. / The objective of this study was to analyze the temporal and spatial distribution of one of the species representative of the macrofauna of sheltered sandy beaches. Measurements using different scales (mesoscale, microscale and time scale) were utilized. The gastropod Olivella minuta, which is abundant in the intertidal region of Baía do Araçá, was used for these analyses. For the mesoscale study, 16 stations were determined within the intertidal region (July/2009) and, in each station, 8 biological samples and 3 samples of sediment were collected. Some abiotic factors (calcium carbonate, organic matter and selection coefficient) had a negative influence on the abundance of the gastropod, while relationship between the O. minuta and other species of the macrofauna were not evident. In a microscale study of tidal ponds (meters) and ripple marks (centimeters), it was observed that, in a centimeter scale, the gastropod was more abundant in places where there was more water in the sediment, whereas in a meter scale the abundance didn\'t vary in or out of the ponds. In a temporal scale, monthly fluctuations of the O. minuta population\'s density were observed, with reduction/absence of individuals between February and March, which suggests that migration and mortality occurred. This study showed that the distribution of O. minuta is influenced by different factors which act in different scales.

Praias arenosas são caracterizadas por uma abundante macrofauna, composta por poliquetas, moluscos e crustáceos. Dentre os moluscos, os gastrópodes constituem um dos grupos mais conspícuos. Entretanto, as informações sobre esse grupo em praias são escassas e se referem principalmente à ocorrência em comunidades. O neogastropoda Olivella minuta é comum e abundante em praias do Litoral Norte de São Paulo. Porém, há importantes lacunas no conhecimento quanto à distribuição desta espécie. Diante desse cenário, o presente estudo visou analisar a distribuição espaço-temporal de Olivella minuta na praia de Barequeçaba, bem como os fatores ambientais relacionados a essa distribuição. Para análise da distribuição espacial de O. minuta ao longo do entre-marés da praia, amostras foram obtidas em outubro de 2009, a partir de doze estações perpendiculares à linha da água, compostas por três transectos com seis níveis cada. Os fatores abióticos (características do sedimento) e bióticos (descritores da macrofauna) que compõem cada estação também foram amostrados e relacionados com a distribuição da espécie. Os resultados revelaram que os indivíduos ocorreram em maior densidade na porção sul da praia, e nos ambientes mais úmidos, próximos a linha da água. O carbonato de cálcio e a matéria orgânica foram os fatores mais determinantes, contrastando com a hipótese de que há influência tanto dos fatores abióticos quanto dos bióticos em tal distribuição. Para análise de distribuição temporal de Olivella minuta no eixo vertical da praia, amostras foram obtidas mensalmente no entremarés, a partir de cinco transectos aleatórios estabelecidos perpendicularmente à linha da água, com nove unidades amostrais. Além disso, amostras foram obtidas trimestralmente, no entremarés e infralitoral, a partir de cinco transectos aleatórios, compostos por nove e seis níveis amostrais, respectivamente. Os resultados revelaram um padrão de distribuição da espécie no entremarés ao longo do tempo, e confirmaram a hipótese de que há uma distribuição de O. minuta de acordo com o tamanho do indivíduos no eixo vertical da praia, com indivíduos menores ocorrendo apenas no infralitoral e migrando para o entremarés ao longo de sua ontogenia. Os avanços apresentados no presente estudo contribuem para o conhecimento sobre a ecologia de populações de praias arenosas, ao relacionar a distribuição de uma espécie da macrofauna com os fatores ambientais, e principalmente ao abranger o infralitoral nas amostragens, por tratar da distribuição de uma espécie cuja distribuição não é exclusiva do entremarés / Sandy beaches have typically abundant macrofauna, comprised of polychaetes, mollusks, and crustaceans. Among mollusks, gastropods comprise one of the most conspicuous groups. Nevertheless, data on this group for beaches are scarce and refer mainly to their occurrence in communities. The neogastropoda Olivella minuta is common and abundant on beaches along the Northern Coast of São Paulo. However, there are important gaps in the knowledge regarding the distribution of this species. Based on this scenario, the present study aims at analyzing the distribution of Olivella minuta in space and over time on Barequeçaba Beach, as well as the related environmental factors. To analyze the distribution of Olivella minuta along the intertidal zone of the beach, samples were obtained in October 2009 from twelve stations perpendicular to the waterline, comprised of three transects with six levels each. Abiotic (sediment characteristics) and biotic (macrofauna descriptors) factors that comprise each station were also sampled and linked to distribution. Results showed that there was higher density of individuals in the southern part of the beach, and in more humid environments, closer to the waterline. Calcium carbonate and organic matter were the most determining factors in the species\' distribution, as opposed to the hypothesis that both abiotic and biotic factors were influencing factors. To analyze the distribution of Olivella minuta over time in the vertical axis of the beach, samples were collected monthly in the intertidal zone, from five random transects set out perpendicularly to the waterline with nine sampling units. In addition, samples were also obtained quarterly with five random transects comprised of nine and six sampling levels in the intertidal zone and in the infralittoral zone, respectively. Results showed a distribution pattern for the species in the intertidal zone over time and confirm the hypothesis that O. minuta is distributed along the vertical axis of the beach according to the size of individuals, with smaller individuals occurring in the infralittoral and migrating to the intertidal zone throughout their ontogeny. Outcomes shown in the present study help improve the knowledge on population ecology of sandy beaches because they relate the distribution of a macrofauna species to environmental factors and mainly due to the fact that sampling covers also the infralittoral zone, since its distribution is not exclusive to the intertidal zone

Praias arenosas são caracterizadas por uma abundante macrofauna, composta por poliquetas, moluscos e crustáceos. Dentre os moluscos, os gastrópodes constituem um dos grupos mais conspícuos. Entretanto, as informações sobre esse grupo em praias são escassas e se referem principalmente à ocorrência em comunidades. O neogastropoda Olivella minuta é comum e abundante em praias do Litoral Norte de São Paulo. Porém, há importantes lacunas no conhecimento quanto à distribuição desta espécie. Diante desse cenário, o presente estudo visou analisar a distribuição espaço-temporal de Olivella minuta na praia de Barequeçaba, bem como os fatores ambientais relacionados a essa distribuição. Para análise da distribuição espacial de O. minuta ao longo do entre-marés da praia, amostras foram obtidas em outubro de 2009, a partir de doze estações perpendiculares à linha da água, compostas por três transectos com seis níveis cada. Os fatores abióticos (características do sedimento) e bióticos (descritores da macrofauna) que compõem cada estação também foram amostrados e relacionados com a distribuição da espécie. Os resultados revelaram que os indivíduos ocorreram em maior densidade na porção sul da praia, e nos ambientes mais úmidos, próximos a linha da água. O carbonato de cálcio e a matéria orgânica foram os fatores mais determinantes, contrastando com a hipótese de que há influência tanto dos fatores abióticos quanto dos bióticos em tal distribuição. Para análise de distribuição temporal de Olivella minuta no eixo vertical da praia, amostras foram obtidas mensalmente no entremarés, a partir de cinco transectos aleatórios estabelecidos perpendicularmente à linha da água, com nove unidades amostrais. Além disso, amostras foram obtidas trimestralmente, no entremarés e infralitoral, a partir de cinco transectos aleatórios, compostos por nove e seis níveis amostrais, respectivamente. Os resultados revelaram um padrão de distribuição da espécie no entremarés ao longo do tempo, e confirmaram a hipótese de que há uma distribuição de O. minuta de acordo com o tamanho do indivíduos no eixo vertical da praia, com indivíduos menores ocorrendo apenas no infralitoral e migrando para o entremarés ao longo de sua ontogenia. Os avanços apresentados no presente estudo contribuem para o conhecimento sobre a ecologia de populações de praias arenosas, ao relacionar a distribuição de uma espécie da macrofauna com os fatores ambientais, e principalmente ao abranger o infralitoral nas amostragens, por tratar da distribuição de uma espécie cuja distribuição não é exclusiva do entremarés / Sandy beaches have typically abundant macrofauna, comprised of polychaetes, mollusks, and crustaceans. Among mollusks, gastropods comprise one of the most conspicuous groups. Nevertheless, data on this group for beaches are scarce and refer mainly to their occurrence in communities. The neogastropoda Olivella minuta is common and abundant on beaches along the Northern Coast of São Paulo. However, there are important gaps in the knowledge regarding the distribution of this species. Based on this scenario, the present study aims at analyzing the distribution of Olivella minuta in space and over time on Barequeçaba Beach, as well as the related environmental factors. To analyze the distribution of Olivella minuta along the intertidal zone of the beach, samples were obtained in October 2009 from twelve stations perpendicular to the waterline, comprised of three transects with six levels each. Abiotic (sediment characteristics) and biotic (macrofauna descriptors) factors that comprise each station were also sampled and linked to distribution. Results showed that there was higher density of individuals in the southern part of the beach, and in more humid environments, closer to the waterline. Calcium carbonate and organic matter were the most determining factors in the species\' distribution, as opposed to the hypothesis that both abiotic and biotic factors were influencing factors. To analyze the distribution of Olivella minuta over time in the vertical axis of the beach, samples were collected monthly in the intertidal zone, from five random transects set out perpendicularly to the waterline with nine sampling units. In addition, samples were also obtained quarterly with five random transects comprised of nine and six sampling levels in the intertidal zone and in the infralittoral zone, respectively. Results showed a distribution pattern for the species in the intertidal zone over time and confirm the hypothesis that O. minuta is distributed along the vertical axis of the beach according to the size of individuals, with smaller individuals occurring in the infralittoral and migrating to the intertidal zone throughout their ontogeny. Outcomes shown in the present study help improve the knowledge on population ecology of sandy beaches because they relate the distribution of a macrofauna species to environmental factors and mainly due to the fact that sampling covers also the infralittoral zone, since its distribution is not exclusive to the intertidal zone