The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Ruth A Stockey - One of the best experts on this subject based on the ideXlab platform.
-
pollen morphology and ultrastructure of Saururaceae
Grana, 2007Co-Authors: Selena Y Smith, Ruth A StockeyAbstract:The fine details of pollen grains in Saururaceae have, until now, been relatively obscure and incomplete. The recent discovery of fossil saururaceous pollen led us to examine the six extant and one fossil species of Saururaceae for details of pollen morphology and ultrastructure. Pollen grains of Saururaceae are characterized as small to minute, boat‐shaped‐elliptic to globose, monosulcate with granulate sculpturing of the aperture membrane, with a punctate tectum. Pollen grains of Houttuynia are the largest. While pollen grains of Anemopsis, Houttuynia, and Saururus have papillae bordering the puncta, those of Gymnotheca are distinctive in lacking such papillae. Similarly, all genera have a smooth tectum, except for Gymnotheca, which has microstriate tectal sculpturing. Pollen grains of Gymnotheca and the fossil have a well‐defined columellar infratectum, while in modern Saururus, Anemopsis and Houttuynia the columellae are irregular in section. Endexine is clearly present in all taxa. This study is the ...
-
establishing a fossil record for the perianthless piperales saururus tuckerae sp nov Saururaceae from the middle eocene princeton chert
American Journal of Botany, 2007Co-Authors: Selena Y Smith, Ruth A StockeyAbstract:: Investigations of small permineralized flowers from the Middle Eocene Princeton Chert, British Columbia, Canada have revealed that they represent an extinct species of Saururus. Over 100 flowers and one partial inflorescence were studied, and numerous minute perianthless flowers are borne in an indeterminate raceme. Each flower is subtended by a bract, and flowers and bracts are borne at the end of a common stalk. Five stamens are basally adnate to the carpels. Pollen is frequently found in situ in the anthers. Examined under SEM and TEM, pollen grains are minute (6-11 μm), monosulcate, boat-shaped-elliptic, with punctate sculpturing and a granulate aperture membrane. The gynoecium is composed of four basally connate, lobed carpels with recurved styles and a single ovule per carpel. Flower structure and pollen are indicative of Saururaceae (Piperales), and in phylogenetic analyses using morphological characters, the fossils are sister to extant Saururus. The fossil flowers are described here as Saururus tuckerae sp. nov. These fossil specimens add to the otherwise sparse fossil record of Piperales, represent the oldest fossils of Saururaceae as well as the first North American fossil specimens of this family, and provide the first evidence of saururaceous pollen in the fossil record.
-
piperales saururus tuckerae sp nov Saururaceae from the middle eocene princeton chert 1
2007Co-Authors: Selena Y Smith, Ruth A StockeyAbstract:Investigations of small permineralized flowers from the Middle Eocene Princeton Chert, British Columbia, Canada have revealed that they represent an extinct species of Saururus. Over 100 flowers and one partial inflorescence were studied, and numerous minute perianthless flowers are borne in an indeterminate raceme. Each flower is subtended by a bract, and flowers and bracts are borne at the end of a common stalk. Five stamens are basally adnate to the carpels. Pollen is frequently found in situ in the anthers. Examined under SEM and TEM, pollen grains are minute (6–11 lm), monosulcate, boat-shaped-elliptic, with punctate sculpturing and a granulate aperture membrane. The gynoecium is composed of four basally connate, lobed carpels with recurved styles and a single ovule per carpel. Flower structure and pollen are indicative of Saururaceae (Piperales), and in phylogenetic analyses using morphological characters, the fossils are sister to extant Saururus. The fossil flowers are described here as Saururus tuckerae sp. nov. These fossil specimens add to the otherwise sparse fossil record of Piperales, represent the oldest fossils of Saururaceae as well as the first North American fossil specimens of this family, and provide the first evidence of saururaceous pollen in the fossil record.
Joao Henrique G Lago - One of the best experts on this subject based on the ideXlab platform.
-
antileishmanial activity and ultrastructural changes of related tetrahydrofuran dineolignans isolated from saururus cernuus l Saururaceae
Journal of Pharmacy and Pharmacology, 2019Co-Authors: Juliana R Brito, Luiz Felipe D Passero, Adriana Bezerrasouza, Marcia Dalastra Laurenti, Paulete Romoff, Henrique Barbosa, Edgard A Ferreira, Joao Henrique G LagoAbstract:OBJECTIVE: This work describes the isolation of anti-Leishmania amazonensis metabolites from Saururus cernuus (Saururaceae). Additionally, ultrastructural changes in promastigotes were evidenced by electron microscopy. METHODS: The MeOH extract from the leaves of S. cernuus was subjected to bioactivity-guided fractionation. Anti-L. amazonensis activity of purified compounds was performed in vitro against promastigote and amastigote forms. KEY FINDINGS: Bioactivity-guided fractionation of the MeOH extract from the leaves of S. cernuus afforded two related tetrahydrofuran dineolignans: threo,threo-manassantin A (1) and threo,erythro-manassantin A (2). Compounds 1 and 2 displayed activity against promastigotes (EC50 of 35.4 ± 7.7 and 17.6 ± 4.2 μm, respectively) and amastigotes (EC50 of 20.4 ± 1.9 and 16.0 ± 1.1 μm, respectively), superior to that determined for the positive control miltefosine (EC50 of 28.7 ± 3.5 μm). Reduced cytotoxicity for host cells was observed for both compounds. Additionally, ultrastructural changes in promastigotes leading to an alteration of structural morphology were observed, as evidenced by electron microscopy. Furthermore, these compounds altered the morphology and physiology of the plasmatic membrane of L. amazonensis. CONCLUSIONS: The obtained results indicated that dineolignans 1 and 2 could be considered as a scaffold for the design of novel and selective drug candidates for the treatment of leishmaniasis.
-
dibenzylbutane neolignans from saururus cernuus l Saururaceae displayed anti trypanosoma cruzi activity via alterations in the mitochondrial membrane potential
Fitoterapia, 2019Co-Authors: Juliana R Brito, Edgard A Ferreira, Thais A Costasilva, Andre G Tempone, Joao Henrique G LagoAbstract:Abstract The MeOH extract from leaves of Saururus cernuus L. (Saururaceae) displayed in vitro activity against trypomastigote forms of T. cruzi (100% of parasite death at 200 μg/mL), suggesting the presence of bioactive compounds. Thus, the bioactivity-guided fractionation was carried out, leading to the isolation of three related neolignan derivatives, identified as threo -austrobailignan-5 ( 1 ), threo -austrobailignan-6 ( 2 ), and threo -dihydroguaiaretic acid ( 3 ). Anti- T. cruzi activity of compounds 1–3 was performed against cell-derived trypomastigotes and intracellular amastigotes. Additionally, the mammalian cytotoxicity was investigated using NCTC cells. Compound 2 was the most effective against extracellular trypomastigotes with IC 50 of 3.7 μM, while compound 3 showed activity in both clinically relevant forms of the parasite, trypomastigotes and amastigotes, with IC 50 values of 7.0 and 16.2 μM, respectively. However, the structurally related compound 1 was inactive. Based on these results, compounds 2 and 3 were selected to evaluate the mechanism of cellular death. Compound 2 induced alteration in the plasma membrane permeability and consequently in the ROS levels after 120 min of incubation. By using flow cytometry and fluorescence microscopy, compound 3 showed alterations in the mitochondrial membrane potential (ΔΨ m ) of trypomastigotes. Considering the promising chemical and biological properties of neolignans 2 and 3 , these compounds could be used as starting points to develop new lead compounds for Chagas disease.
Selena Y Smith - One of the best experts on this subject based on the ideXlab platform.
-
Seed fertilization, development, and germination in Hydatellaceae (Nymphaeales): Implications for endosperm evolution in early angiosperms
American Journal of Botany, 2009Co-Authors: Paula J. Rudall, Selena Y Smith, Margarita V. Remizowa, Tilly Eldridge, Julia Tratt, Margaret M. Ramsay, Renee E. Tuckett, Margaret E. Collinson, Dmitry D. SokoloffAbstract:: New data on endosperm development in the early-divergent angiosperm Trithuria (Hydatellaceae) indicate that double fertilization results in formation of cellularized micropylar and unicellular chalazal domains with contrasting ontogenetic trajectories, as in waterlilies. The micropylar domain ultimately forms the cellular endosperm in the dispersed seed. The chalazal domain forms a single-celled haustorium with a large nucleus; this haustorium ultimately degenerates to form a space in the dispersed seed, similar to the chalazal endosperm haustorium of waterlilies. The endosperm condition in Trithuria and waterlilies resembles the helobial condition that characterizes some monocots, but contrasts with Amborella and Illicium, in which most of the mature endosperm is formed from the chalazal domain. The precise location of the primary endosperm nucleus governs the relative sizes of the chalazal and micropylar domains, but not their subsequent developmental trajectories. The unusual tissue layer surrounding the bilobed cotyledonary sheath in seedlings of some species of Trithuria is a belt of persistent endosperm, comparable with that of some other early-divergent angiosperms with a well-developed perisperm, such as Saururaceae and Piperaceae. The endosperm of Trithuria is limited in size and storage capacity but relatively persistent.
-
pollen morphology and ultrastructure of Saururaceae
Grana, 2007Co-Authors: Selena Y Smith, Ruth A StockeyAbstract:The fine details of pollen grains in Saururaceae have, until now, been relatively obscure and incomplete. The recent discovery of fossil saururaceous pollen led us to examine the six extant and one fossil species of Saururaceae for details of pollen morphology and ultrastructure. Pollen grains of Saururaceae are characterized as small to minute, boat‐shaped‐elliptic to globose, monosulcate with granulate sculpturing of the aperture membrane, with a punctate tectum. Pollen grains of Houttuynia are the largest. While pollen grains of Anemopsis, Houttuynia, and Saururus have papillae bordering the puncta, those of Gymnotheca are distinctive in lacking such papillae. Similarly, all genera have a smooth tectum, except for Gymnotheca, which has microstriate tectal sculpturing. Pollen grains of Gymnotheca and the fossil have a well‐defined columellar infratectum, while in modern Saururus, Anemopsis and Houttuynia the columellae are irregular in section. Endexine is clearly present in all taxa. This study is the ...
-
establishing a fossil record for the perianthless piperales saururus tuckerae sp nov Saururaceae from the middle eocene princeton chert
American Journal of Botany, 2007Co-Authors: Selena Y Smith, Ruth A StockeyAbstract:: Investigations of small permineralized flowers from the Middle Eocene Princeton Chert, British Columbia, Canada have revealed that they represent an extinct species of Saururus. Over 100 flowers and one partial inflorescence were studied, and numerous minute perianthless flowers are borne in an indeterminate raceme. Each flower is subtended by a bract, and flowers and bracts are borne at the end of a common stalk. Five stamens are basally adnate to the carpels. Pollen is frequently found in situ in the anthers. Examined under SEM and TEM, pollen grains are minute (6-11 μm), monosulcate, boat-shaped-elliptic, with punctate sculpturing and a granulate aperture membrane. The gynoecium is composed of four basally connate, lobed carpels with recurved styles and a single ovule per carpel. Flower structure and pollen are indicative of Saururaceae (Piperales), and in phylogenetic analyses using morphological characters, the fossils are sister to extant Saururus. The fossil flowers are described here as Saururus tuckerae sp. nov. These fossil specimens add to the otherwise sparse fossil record of Piperales, represent the oldest fossils of Saururaceae as well as the first North American fossil specimens of this family, and provide the first evidence of saururaceous pollen in the fossil record.
-
piperales saururus tuckerae sp nov Saururaceae from the middle eocene princeton chert 1
2007Co-Authors: Selena Y Smith, Ruth A StockeyAbstract:Investigations of small permineralized flowers from the Middle Eocene Princeton Chert, British Columbia, Canada have revealed that they represent an extinct species of Saururus. Over 100 flowers and one partial inflorescence were studied, and numerous minute perianthless flowers are borne in an indeterminate raceme. Each flower is subtended by a bract, and flowers and bracts are borne at the end of a common stalk. Five stamens are basally adnate to the carpels. Pollen is frequently found in situ in the anthers. Examined under SEM and TEM, pollen grains are minute (6–11 lm), monosulcate, boat-shaped-elliptic, with punctate sculpturing and a granulate aperture membrane. The gynoecium is composed of four basally connate, lobed carpels with recurved styles and a single ovule per carpel. Flower structure and pollen are indicative of Saururaceae (Piperales), and in phylogenetic analyses using morphological characters, the fossils are sister to extant Saururus. The fossil flowers are described here as Saururus tuckerae sp. nov. These fossil specimens add to the otherwise sparse fossil record of Piperales, represent the oldest fossils of Saururaceae as well as the first North American fossil specimens of this family, and provide the first evidence of saururaceous pollen in the fossil record.
Juliana R Brito - One of the best experts on this subject based on the ideXlab platform.
-
antileishmanial activity and ultrastructural changes of related tetrahydrofuran dineolignans isolated from saururus cernuus l Saururaceae
Journal of Pharmacy and Pharmacology, 2019Co-Authors: Juliana R Brito, Luiz Felipe D Passero, Adriana Bezerrasouza, Marcia Dalastra Laurenti, Paulete Romoff, Henrique Barbosa, Edgard A Ferreira, Joao Henrique G LagoAbstract:OBJECTIVE: This work describes the isolation of anti-Leishmania amazonensis metabolites from Saururus cernuus (Saururaceae). Additionally, ultrastructural changes in promastigotes were evidenced by electron microscopy. METHODS: The MeOH extract from the leaves of S. cernuus was subjected to bioactivity-guided fractionation. Anti-L. amazonensis activity of purified compounds was performed in vitro against promastigote and amastigote forms. KEY FINDINGS: Bioactivity-guided fractionation of the MeOH extract from the leaves of S. cernuus afforded two related tetrahydrofuran dineolignans: threo,threo-manassantin A (1) and threo,erythro-manassantin A (2). Compounds 1 and 2 displayed activity against promastigotes (EC50 of 35.4 ± 7.7 and 17.6 ± 4.2 μm, respectively) and amastigotes (EC50 of 20.4 ± 1.9 and 16.0 ± 1.1 μm, respectively), superior to that determined for the positive control miltefosine (EC50 of 28.7 ± 3.5 μm). Reduced cytotoxicity for host cells was observed for both compounds. Additionally, ultrastructural changes in promastigotes leading to an alteration of structural morphology were observed, as evidenced by electron microscopy. Furthermore, these compounds altered the morphology and physiology of the plasmatic membrane of L. amazonensis. CONCLUSIONS: The obtained results indicated that dineolignans 1 and 2 could be considered as a scaffold for the design of novel and selective drug candidates for the treatment of leishmaniasis.
-
dibenzylbutane neolignans from saururus cernuus l Saururaceae displayed anti trypanosoma cruzi activity via alterations in the mitochondrial membrane potential
Fitoterapia, 2019Co-Authors: Juliana R Brito, Edgard A Ferreira, Thais A Costasilva, Andre G Tempone, Joao Henrique G LagoAbstract:Abstract The MeOH extract from leaves of Saururus cernuus L. (Saururaceae) displayed in vitro activity against trypomastigote forms of T. cruzi (100% of parasite death at 200 μg/mL), suggesting the presence of bioactive compounds. Thus, the bioactivity-guided fractionation was carried out, leading to the isolation of three related neolignan derivatives, identified as threo -austrobailignan-5 ( 1 ), threo -austrobailignan-6 ( 2 ), and threo -dihydroguaiaretic acid ( 3 ). Anti- T. cruzi activity of compounds 1–3 was performed against cell-derived trypomastigotes and intracellular amastigotes. Additionally, the mammalian cytotoxicity was investigated using NCTC cells. Compound 2 was the most effective against extracellular trypomastigotes with IC 50 of 3.7 μM, while compound 3 showed activity in both clinically relevant forms of the parasite, trypomastigotes and amastigotes, with IC 50 values of 7.0 and 16.2 μM, respectively. However, the structurally related compound 1 was inactive. Based on these results, compounds 2 and 3 were selected to evaluate the mechanism of cellular death. Compound 2 induced alteration in the plasma membrane permeability and consequently in the ROS levels after 120 min of incubation. By using flow cytometry and fluorescence microscopy, compound 3 showed alterations in the mitochondrial membrane potential (ΔΨ m ) of trypomastigotes. Considering the promising chemical and biological properties of neolignans 2 and 3 , these compounds could be used as starting points to develop new lead compounds for Chagas disease.
Shirley C Tucker - One of the best experts on this subject based on the ideXlab platform.
-
floral ontogeny of zippelia begoniaefolia and its familial affinity Saururaceae or piperaceae
American Journal of Botany, 1995Co-Authors: Shirley C Tucker, Liang HanxingAbstract:Zippelia begoniaefolia Bl., a monotypic species having characteristics of both Piperaceae and Saururaceae, has racemes of about 20 small flowers lacking a perianth, each with six free stamens and a four-carpellate syncarpous gynoecium. The inflorescence apical meristem initiates bracts acropetally and helically, each of which subtends a later initiated single floral apex; there are no ''common'' primordia. The six stamens are initiated as two lateral pairs and two solitary successive primordia, the latter two opposite in median sagittal positions. Four carpel primordia are initiated as a lateral pair and two successively initiated in the median sagittal plane. This order of organ inception is unique among Piperaceae and Saururaceae. Intercalary growth below carpellary attachment raises them up on a common cylindrical base that becomes the syncarpous ovary, covered with unique glochidiate hairs and containing a single basal ovule. The free portions of the carpels become the reflexed papillate stigmas. The floral vascular system has a single bundle at base that branches to supply the bract and flower traces. The floral vasculature is similar but not identical to that of Saururus (Saururaceae) and some Piper species (Piperaceae). Plesiomorphic character states of Zippelia that are shared with Saururus include hypogyny, free stamens, cleft stigma, and a similar floral groundplan. Synapomorphies, derived shared character states that unite Zippelia with Piperaceae; include syncarpy, solitary ovule, basal placentation, fused ventral carpellary bundles, and a double vascular cylinder in the stem. Cladistic analysis aligns Zippelia with Piperaceae because they share apomorphies, and because Zippelia shares only plesiomorphies with Saururus.
-
comparative study of the floral vasculature in Saururaceae
American Journal of Botany, 1990Co-Authors: Liang Hanxing, Shirley C TuckerAbstract:The floral vascular systems are compared among all six taxa of Saururaceae, including the two species of Gymnotheca which have not been studied previously. All are zygomorphic not radial as sometimes reported, in conformity with dorsiventral symmetry during organogenesis
