The combat against viral diseases has been, and still is, a major challenge in the field of drug development. Viruses are intracellular parasites that use the host cell ma-chinery for their replication and release. Therefore it is difficult to target and destroy the viral particle without disturbing the essential functions of the host cell. This thesis describes studies towards antiviral agents targeting adenovirus type 37 (Ad37), which causes the severe ocular infection epidemic keratoconjunctivitis (EKC). Cell surface oligosaccharides serve as cellular receptors for many pathogens, including viruses and bacteria. For EKC-causing adenoviruses, cell surface oligo-saccharides with terminal sialic acid have recently been shown to be critical for their attachment to and infection of host cells. The work in this thesis support these re-sults and identifies the minimal binding epitope for viral recognition. As carbo-hydrate–protein interactions in general, the sialic acid–Ad37 interaction is very weak. Nature overcomes this problem and vastly improves the binding affinity by presenting the carbohydrates in a multivalent fashion. Adenoviruses interact with their cellular receptors via multiple fiber proteins, whereby it is likely that the ideal inhibitor of adenoviral infections should be multivalent. This thesis includes design and synthesis of multivalent sialic acid glycoconjugates that mimic the structure of the cellular receptor in order to inhibit adenoviral attachment to and infection of human corneal epithelial (HCE) cells. Synthetic routes to three different classes of sialic acid conjugates, i.e. derivatives of sialic acid, 3’-sialyllactose and N-acyl modified sialic acids, and their multivalent counterparts on human serum albumine (HSA) have been developed. Evaluation of these conjugates in cell binding and cell infectivity assays revealed that they are effective as inhibitors. Moreover the results verify the hypothesis of the multivalency effect and clearly shows that the power of inhibition is significantly increased with higher orders of valency. Potential inhibi-tors could easily be transferred to the eye using a salve or eye drops, and thereby they would escape the metabolic processes of the body, a major drawback of using carbohydrates as drugs. The results herein could therefore be useful in efforts to develop an antiviral drug for treatment of EKC.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 134-148).

Dans la communauté scientifique, la glycosylation suscite un vif intérêt tant les relations existantes entre les sucres et les protéines sont étroites et sont impliquées dans de nombreux processus biologiques. De nombreuses méthodologies de synthèse ont été développées pour permettre la production de glycoprotéines sous forme homogènes nécessaires pour leur étude. Les formes S-glycosidiques sont d’un intérêt particulier grâce notamment à la réactivité de l’atome de soufre qui permet le couplage spécifique sucre – acide aminé et qui confère à la liaison une relative résistance à l’hydrolyse acido/basique et enzymatique. Dans le cadre de ce projet nous avons souhaité utiliser des outils biocatalytiques pour proposer une nouvelle voie d’accès aux protéines S-glycosylées en s’appuyant sur le concept des thioglycoligases. Pour répondre à ce challenge, nous nous sommes intéressés à la production d’une banque de glycosidases natives à partir du génome de la bactérie thermophile Dictyoglomus thermophilum. Trois protéines originales ont pu être produites, caractérisées et criblées en activité transglycosylase. Parmi ces dernières la β-glycosidase DtGly s’est révélée être un biocatalyseur efficace en favorisant la synthèse d’une variété de glycosides d’alkyle et de glycosyl glycérol. Par la suite, neuf mutants thioglycoligases ont été produits par mutagénèse dirigée à partir des glycosidases natives. A l’issue de leur criblage en activité thioligase, le mutant de DtGly E159Q a été retenu pour la synthèse de S-glycoconjugués. Une étude de relation structure/activité menée sur l’enzyme mutée nous a conduit à la synthèse d’un acide aminé non-naturel, la Thiotyrosine. L’essai de glycosylation de l’analogue estérifié de cette Thiotyrosine par DtGly E159Q a été suivi par LC-MS et a permis de mettre en évidence la formation du produit de thioglucosylation. Ce premier résultat préliminaire s’avère très prometteur pour la validation du concept de S-glycosylation d’un acide aminé catalysée par une thioglycoligase. / Glycosylation, one of the most complex co- and post-translationnal modifications of proteins, is of utmost importance for the scientific community as carbohydrates and proteins are closely related and involved in numerous diseases. The need to access homogeneous glycoproteins allows the development of a wide range of synthetic methods. Among them S-glycosidic forms have been attractive thanks to the reactivity of sulfur atom which allows the specific sugar – amino acid conjugation and confers a relative resistance through acido/basic or enzymatic hydrolysis. In this project we attempt to take advantage of natural tools to develop an enzymatic methodology to prepare S-glycosylated proteins through the thioglycoligase concept. In order to take up this challenge we first generate an enzymatic pool of wild type glycosidases from the thermophilic bacteria Dictyoglomus thermophilum. Activity screening of the three proteins produced and characterized allows the isolation of the β-glycosidase DtGly with good transglycosylation activity, thus affording a variety of alkyl glycosides and glyceroglycosides. Next we generate nine thioglycoligase mutants through site-directed mutagenesis and after screening of activity, the variant DtGly E159Q was selected to produce S-glycoconjugates. Finally, DtGly E159Q relation structure/activity studies led us to synthesize the unnatural amino acid Thiotyrosine. Enzymatic thioglucosylation assay catalyzed by DtGly E159Q was monitored by LC-MS and gave converging evidence of the successful formation of the S-glucosylated Thiotyrosine. This tremendous preliminary result is promising for further investigations of enzymatic S-glycosylation of amino acid using thioglycoligases as toolbox.

No description available.

No description available.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Lectinas sÃo proteÃnas que apresentam afinidade por carboidratos especÃficos. E-xiste um considerÃvel interesse pelos carboidratos de superfÃcie celular posto que estÃo relacionados com fenÃmenos de diferenciaÃÃo e maturaÃÃo. Durante a transformaÃÃo neoplÃsica ocorrem alteraÃÃes da membrana celular, principalmente na composiÃÃo de carboidratos, que determinam caracterÃsticas especiais Ãs cÃlulas. Lectinas tÃm sido utili-zadas como ferramentas em muitas Ãreas de investigaÃÃo diagnÃstica, especialmente no estudo dos glicoconjugados celulares. No presente estudo investigou-se a expressÃo de glicoconjugados especÃficos para Artocarpus incisa (frutalina) em vÃrios estÃgios histolÃ-gicos de progressÃo tumoral na mama. Foram incluÃdas amostras de epitÃlio normal, metaplasia apÃcrina, hipreplasia ductal tÃpica e atÃpica, carcinoma ductal in situ, carci-noma ductal invasivo e metÃstase ganglionar. As amostras foram marcadas utilizando o mÃtodo da EstreptoâAvidinaâBiotinaâPeroxidase com duas tÃcnicas diferentes: a frutali-na, como sonda primÃria e o anticorpo anti-frutalina como ponte (TÃcnica I); anticorpo anti-frutalina como sonda primÃria (TÃcnica II). Em ambas as tÃcnicas ocorreu coloraÃÃo mais forte no epitÃlio alterado do que no normal, sendo o predomÃnio da coloraÃÃo membranar. Muitos dos carcinomas ductais in situ tambÃm coraram tanto a membrana quanto a citoplasma, pela TÃcnica I; com a tÃcnica II, o predomÃnio foi de citoplasma. Todos os carcinomas ductais invasivos coraram fortemente, com ligeira predominÃncia do citoplasma, quando foi utilizada a TÃcnica I. Um nÃmero menor de casos corou com a TÃcnica II. Com esta tÃcnica nenhuma das hiperplasias atÃpicas corou a membrana, aliÃs, a partir das hiperplasias atÃpicas houve um decrÃscimo na marcaÃÃo das membranas e um ganho na marcaÃÃo do citoplasma. Este trabalho mostrou que a frutalina à um mar-cador de cÃlulas epiteliais. Revela que durante a progressÃo tumoral houve modificaÃÃo de glicoconjugados da superfÃcie celular expondo resÃduos de galactose. O anticorpo anti-frutalina marcou cÃlulas epiteliais, aparentemente de forma especÃfica, porÃm sem-pre em menor nÃmero de casos. / Lectins are proteins which bind specifically to carbohydrates. Recently consider-able interest has been devoted to cell surface carbohydrates, since they are related to differentiation and maturation phenomena. Neoplastic transformation in cells is associ-ated to altered cell surface membranes, particularly with an abnormal composition. This may determine of neoplastics cell characteristics. Lectins have been used as tools in many areas of diagnostic investigation especially related to changes in the expressions of membrane and cytoplasmatic carbohydrates. In this study it has been examined the ex-pression of glycoconjugates especific to Artocarpus incisa lectin (frutalina) in various his-tological stages of tumor progression in the breast tissues. These included normal epithe-lium, apocrine metaplasia, ductal hyperplasia, without and with atypia, ductal carcino-ma in situ, invasive ductal carcinoma and nodal metastasis. This tissue was stained to bind to the lectin using two different histochemical techniques: frutalina reacting direct-ly (Technique I) and antibody anti-frulalina as a bridge; antibody anti-frutalina reacting directly (Technique II). In both techniques the staining was more frequent in malignant than in benign breast epithelium. Most of the ductal carcinomas in situ stained the mem-brane as well as the citoplasm. All invasive ductal carcinomas were stained by frutalina. During the tumor progression there occurred modifications on the glycoconjugate cellu-lar surfaces showing galactose residues. The most interesting aspect of this study was that the antibody anti-frutalina did not stained any of the cases of atypical hyperplasia.

Made available in DSpace on 2018-06-27T18:55:57Z (GMT). No. of bitstreams: 3 Danieli Ferrari da Rosa.pdf: 3718059 bytes, checksum: bb8ef19a5af8a3faa7687e991e0d5c3d (MD5) Danieli Ferrari da Rosa.pdf.txt: 158457 bytes, checksum: b6b83ac5211b5e9ee8b9dfba9feba1d9 (MD5) Danieli Ferrari da Rosa.pdf.jpg: 3270 bytes, checksum: 1f0862e05ecb2e7b1da2056322eeeaab (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The sialic acid is the generic name of carboxylated monosaccharides family with nine carbon glycoconjugated at terminal portion. These molecule family are involved in several biological processes such cell recognition processes, platelet adhesion, migration, invasion and metastatic potential, it also work as a receptor for bacteria and viruses. High concentrations of total sialic acid in the blood have been reported in different groups of patients with brain tumors, leukemia, melanoma, carcinoma and other kinds of cancers. The cleavage of sialic acid is a crucial step in virus infection influenzae, since this acid is part of the cellular receptor that the virus uses during the process of cellular internalization. The neuraminidase, an enzyme produced by the virus, cleaves the bond between sialic acid and the viral glycoproteins, allowing the entry of viruses into cells.The aim of this study was the analysis of serum sialic acid levels in murine melanoma and Herpes Simplex virus-1 (HSV-1) infection model. In the tumor model were used C57BL/6 and in the viral model BALB/c mice. Mice were injected with 2x105 B16F10 cells subcutaneously in the thigh and the tumor progression was followed each day till it became visible. The HSV-1 infection was conducted by intraperitoneally injection of with 102 PFU of virus. The sialic acid in serum samples was quantified by thiobarbituric method in spectrophotometer at 549 nm. A standard curve with commercial sialic acid was used as parameter for quantification. The results showed that in tumor model the sialic acid was increased compared with control group and have significant difference (p <0.05) in the first day after administration of cells. For the viral infection the concentration of sialic acid showed a significant difference (p <0,05) in the first day after infection when compared infected with control group. The histological analysis in thigh of mice performed 24 hours after administration of B16F10 cells were found compact groups of round or polygonal melanocytes with clear and large cytoplasm, irregular chromatin, hyperchromatic and vacuolated nuclei, eosinophilic nucleoli and atypical mitosis. / O ácido siálico é o nome genérico dado a família de monossacarídeos carboxilados com nove átomos de carbono que aparece na porção terminal de glicoconjugados. Estas moléculas estão envolvidas em vários processos biológicos, tais como, processos de reconhecimento celular, adesão plaquetária, migração, invasão, potencial metastático, sendo também um receptor para bactérias e vírus. O aumento das concentrações séricas de ácido siálico total tem sido descrito em vários grupos de pacientes que sofrem de tumores cerebrais, leucemia, melanoma, carcinoma e outros tipos de cânceres. A clivagem do ácido siálico é um passo crucial para a infecção do vírus Influenza, uma vez que este ácido é parte do receptor celular usado pelo vírus durante o processo de internalização celular. A neuraminidase, enzima produzida pelo vírus, cliva a ligação entre o ácido siálico e as glicoproteínas virais, permitindo a entrada dos vírus nas células. O objetivo desse estudo foi analisar os níveis séricos de ácido siálico em modelo de melanoma murino e modelo de infecção herpética (HSV-1). No modelo tumoral foram utilizados camundongos C57BL/6 e no modelo viral camundongos BALB/c. Os camundongos receberam 2x105 células B16F10 através da administração subcutânea na coxa e a progressão do tumor foi acompanhada todos os dias até o tumor se tornar visível. A infecção com HSV-1 foi realizada através da administração intraperitoneal de 102 PFU de vírus. O ácido siálico das amostras de soro foram quantificadas pelo método tiobarbitúrico em espectrofotômetro à 549 nm. Uma curva padrão com ácido siálico comercial foi usada como parâmetro para a quantificação. Os resultados mostraram que as concentrações de ácido siálico no modelo tumoral foram aumentadas nos animais com tumor quando comparadas ao grupo controle e houve diferença significativa (p< 0,05) no primeiro dia após a administração das células. Para o modelo de infecção viral houve diferença significativa (p< 0,05) no primeiro dia após a infecção quando comparado o grupo infectado com o controle. Na análise histológica da coxa dos camundongos realizada após 24 horas da administração de células B16F10 foram encontrados grupos compactos de melanócitos arredondados ou poligonais, com citoplasma amplo e claro, cromatina irregular, núcleos hipercromáticos e vacuolizados, nucléolos eosinofílicos e mitoses atípicas.

Made available in DSpace on 2014-06-11T19:26:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-22Bitstream added on 2014-06-13T20:33:37Z : No. of bitstreams: 1 mattos_ccb_me_sjrp.pdf: 1833064 bytes, checksum: 9ddfdfa24b297a8db2f0d8e4747e5c43 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O Toxoplasma gondii infecta os seres humanos dentre outras vias, pelo trato gastrintestinal, um local onde se dá a expressão do perfil de glicoconjugados ABH sob controle da enzima a-2-L-Fucosiltransferase (FUTII) codificada pelo gene FUT2 (19q13.3). A presença da FUTII define o status secretor positivo, o qual é relacionado aos fenótipos eritrocitários ABO. Diante da importância epidemiológica e clínica da infecção pelo T. gondii, o objetivo desse trabalho foi testar a hipótese de que o perfil de glicoconjugados ABH expresso no trato gastrintestinal está associado à infecção por esse parasito. Foram selecionadas 367 gestantes atendidas no Ambulatório de Gestação de Alto Risco do Hospital de Base da Fundação Faculdade Regional de Medicina de São José do Rio Preto. Duas amostras de sangue, uma sem e outra com anticoagulante foram coletadas. A fenotipagem eritrocitária ABO e a detecção dos anticorpos anti-T. gondii foram realizadas pelo método hemaglutinação. A identificação do status secretor foi feita pelo método PCR-RFLP. As diferenças nas freqüências do status secretor positivo e negativo e dos fenótipos eritrocitários ABO, isoladamente ou em conjunto, não foram estatisticamente significantes na presença e na ausência desses anticorpos (p=0,26). Esses resultados sugerem que o perfil de glicoconjugados ABH expressos no trato gastrintestinal sob controle do gene FUT2 não está associado à presença de anticorpos anti-T. gondii. / Toxoplasma gondii infects humans in several manners including by the gastrointestinal tract where the a-2-L-Fucosiltransferase (FUTII) coded by FUT2 (19q13.3) controls the expression of the ABH glycoconjugates profile. Presence of FUTII defines the positive secretor status which is associated to ABO erythrocytic phenotypes. Due to the epidemiological and clinical importance of T. gondii infection, the aim of this work was to test the hypothesis that the ABH glycoconjugate profile expressed in the gastrointestinal tract is associated to infections by this parasite. A total of 367 pregnant women from the High-Risk Pregnancy Clinical of the University Hospital de Base in São José do Rio Preto were enrolled in this study. Two blood samples were drawn with only one mixed with anticoagulant. The ABO erythrocytic phenotyping and detection of anti-T. gondii antibodies were achieved by the hemagglutination method. Identification of the secretor status was by the PCR-RFLP method. Differences in the positive and negative secretor status and ABO erythrocytic phenotypes, either in isolation or in association, were not statistically significant in respect to the presence or absence of these antibodies (p-value =0.26). These results suggest that the ABH glycoconjugate profile expressed in the gastrointestinal tract under control of the FUT2 gene is not associated to anti-T. gondii antibodies.

Synopsis The thesis entitled “Synthesis of Glyco-amino-acids, Glycosyl-amino-acids, and α-Amino γ-Lactams from Carbohydrate Derived Donor-Acceptor Cyclopropanes” is divided into five chapters. Chapter 1: Introduction and Background: Carbohydrate Derived Cyclopropanes and Glycoconjugates of Amino Acids and Peptides In this chapter, introduction and background on cyclopropanes, carbohydrate derived DA-cyclopropanes, glycopeptides and its mimetics is discussed Chapter 2: Efficient Synthesis of Glycosyl Esters of Amino Acids from Carbohydrate Derived Cyclopropanecarboxylates In this chapter, the N-iodosuccinimide (NIS) mediated ring opening of carbohydrate derived donor-acceptor (DA) cyclopropanes with carboxylic group of various N-protected amino acids is discussed. Under mild conditions, glucosyl esters of amino acids have been synthesized in moderate to good yields. This methodology has also been applied to galactose derived DA-cyclopropanes for the synthesis of galactosyl-amino-acid derivative. Among three N-protected valine derivatives (–Fmoc, –Boc, and –Cbz), the reaction of N-Fmoc protected valine derivative of glycosyl-amino-acid has not been successful due to the steric hindrance of bulky Fmoc group. Chapter 3: Synthesis of O–Linked Glycosyl-amino-acids & C–Linked Glyco-amino-acids. In this chapter, the synthesis of glycosyl-amino-acids and glyco-amino-acids by the NIS mediated ring opening of carbohydrate derived DA-cyclopropanes is reported. To synthesize the precursors of glycopeptides, deprotection of NHBoc has been performed with trifluoroacetic acid (TFA) and trimethylsilyl chloride (TMSCl). Trimethylsilyl chloride is found to be a better reagent than trifluoroacetic acid for this reaction. The synthesis of both O–linked glycosyl-amino acids and C–linked glycopeptides from single starting material using the orthogonal strategy at amine groups has been achieved. In these glycoconjugates of amino acids, the azide group (–N3) has been used as a masked amine (–NH2) which circumvents the protection and deprotection steps. Chapter 4: Synthesis of Carbohydrate Fused α-Amino γ-Lactams. In this chapter a flexible protocol for the synthesis of carbohydrate fused α-Amino γ-Lactams from carbohydrate derived cyclopropanecarboxylates has been disclosed. Also, the synthesis of carbohydrate fused γ-Lactams in a single-step from the iodo-azide by reductive cyclization has been reported. The formation of -lactam is achieved in low yield using both methods (A & B). The utility of the carbohydrate fused α-Amino γ-Lactams in the synthesis of Agl-bridged glycopeptide conjugates in a single-step with high efficiency has been demonstrated. Chapter 5: Studies on the Synthesis of Septanosides from Carbohydrate Derived DA-Cyclopropanes In carbohydrate derived DA 1,2-cyclopropanes, generally, the electron withdrawing group is attached at C-7 (type-I), C-2 (type-II), or C-3 (type-III). In this chapter, studies on the synthesis and use of carbohydrate derived DA-cyclopropanes of type-II & -III to form the the septanoside derivatives have been described. Attempts at the synthesis of 3,4,6-tri-O-methyl-D-glucal derived cyclopropanecarboxylates of type-II have not been successful. The failure of the cyclopropanation reactions might be due to presence of the carbmethoxy group at C-2 causing steric hindrance on the olefinic bond of 3,4,6-tri-O-tri-methyl-D-glucal methyl ester. It was then speculated that replacement of the of the carboxylate group in tri-O-methyl-glucal with hydroxymethyl group can promote the cyclopropanation reaction. Cyclopropanation of benzyl protected corresponding alcohol furnished the desired cyclopropane derivative in moderate yield (48%) as an inseparable mixture of diastereomers (1:1). Hence the synthesis of cyclopropanecarboxylates of type-II has not been achieved using this methodology. Glucose derived 3-oxo-1,2-cyclopropanes is synthesized from 3,4,6-tri-O-acetyl-D-glucal in good yield. This glucose derived cyclopropane of type-III did not furnish the septanoside derivative under different conditions. The synthesis of 3-oxo-1,2-cyclopropanated galactose derivative has been achieved in reasonably good yield from D-galactal with in three steps. When the galactose derived DA-cyclopropane is reacted with NIS and MeOH in the presence of catalytic amount of TMSOTf, it furnished the desired septanoside along with many side-products. The attempts at separation and identification of the septanoside in pure form have not been successful.

Submitted by Luis Ricardo Andrade da Silva (lrasilva@uefs.br) on 2016-02-22T22:50:07Z No. of bitstreams: 1 Disserta??o_Alex_RGV_Final2.pdf: 2862200 bytes, checksum: e222cf5496c76484ec34f8fdd9012d23 (MD5) / Made available in DSpace on 2016-02-22T22:50:07Z (GMT). No. of bitstreams: 1 Disserta??o_Alex_RGV_Final2.pdf: 2862200 bytes, checksum: e222cf5496c76484ec34f8fdd9012d23 (MD5) Previous issue date: 2015-11-16 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / In Brazil, research on Arecaceae pollen grains are related to melissopalynology, the palynotaxonomy, being scarce the physiology of pollen. Reproductive biology studies pollination are of great importance in different cultures, from their results can obtain parameters to be used to obtain a considerable increase in the production of croops, as well as the size and quality of fruits, helping for good economic income of the producers. In vitro pollen germination also allows you to check its viability and reproductive strength, and are important tools in breeding programs of plants, assisting in the selection of the most effective genotypes and training hybrids. The chapter one of this work consists of evaluation of the type of culture medium and implications on the choice of micronutrients which form part of its composition, as well as the pretreatment of specimens. It was observed that oil palm pollen (Elaeis guineensis Jacq.) Showed an increase in germination rates after being dissected for a period of four hours and the culture medium with only boric acid and calcium nitrate, in addition to the power source (sucrose) are efficient to display their germination potential. Chapter two contained in the evaluation glycoconjugate (lectins) on the pollen germination of oil palm, which was discussed metabolic interactions of these processes. Lectins are important regulators and operate in recognition and acknowledgment of pollen on the pistil and can act as genetic incompatibility factors. Germination was evaluated in BCa means (boron and calcium) with the addition of lectins: Crotalaria pallida lectin (CPL), Concanavalin A (ConA) and Jacalin (JAC) in two concentrations. An increase of the germination rate in the presence of ConA and CPL lectins and inhibition in the presence of JAC. The results of this study were valuable, since aggregate informative values and extend discussions on the processes involving the germination of pollen grains and formation of pollen tubes of oil palm. / No Brasil, pesquisas com gr?os de p?len da fam?lia Arecaceae est?o relacionados ? melissopalinologia e palinotaxonomia, sendo escassos aqueles voltados ? fisiologia do p?len. Estudos de biologia reprodutiva relacionados ? poliniza??o s?o de grande import?ncia nas diversas culturas, visto que a partir dos seus resultados pode se obter par?metros a serem utilizados visando o aumento consider?vel da produ??o de plantas cultivadas, bem como no tamanho e na qualidade dos frutos, contribuindo para bons rendimentos econ?micos dos produtores. A germina??o de gr?os de p?len in vitro tamb?m permite verificar seu vigor reprodutivo, sendo importante ferramentas em programas de melhoramento gen?tico de plantas, auxiliando na sele??o de gen?tipos mais eficazes para cruzamentos e forma??o de h?bridos. O cap?tulo um deste trabalho teve como prop?sito avaliar o tipo de meio de cultura e as implica??es da escolha dos micronutrientes que fazem parte da sua composi??o, bem como do tratamento pr?vio das amostras. Foi observado que o p?len de dendezeiro (Elaeis guineensis Jacq.) apresentou aumento nas taxas de germina??o depois de ser desidratado por um per?odo de quatro horas e que o meio de cultura com apenas ?cido b?rico e nitrato de c?lcio, al?m da sacarose como fonte de energia, s?o eficientes para exibir o potencial germinativo. O cap?tulo dois consta da avalia??o de prote?nas glicoconjugadas (lectinas) sobre a germinabilidade pol?nica do dendezeiro. Foram discutidas as intera??es metab?licas desses processos, bem como o papel das lectinas que s?o importantes reguladores sobre a recogni??o e reconhecimento do p?len no pistilo, podendo atuar como fatores de incompatibilidade gen?tica. Foi avaliada a germina??o em meio BCa (boro e c?lcio) com adi??o das lectinas: Lectina de Crotalaria pallida Aiton (CPL), Concanavalina A (ConA) e Jacalina (JAC), em duas concentra??es. Verificou-se aumento das taxas de germina??o na presen?a das lectinas CPL e ConA e inibi??o da germina??o na presen?a da JAC. Os resultados deste trabalho agregam valores informativos sobre a compreens?o da biologia reprodutiva de dendezeiro (Arecaceae) ocorrente na ?Costa do Dend??/Bahia e ampliam as discuss?es sobre os processos que envolvem a germina??o de gr?os de p?len e forma??o dos tubos pol?nicos.