Distributional Patterns of Diatoms and Limnodrilus Oligochaetes in a Kenyan Dry Streambed Following the 1999–2000 Drought Conditions

Drought is a natural phenomenon experienced by many intermittent and also seasonal lotic systems. It has diverse effects on the structure and distribution of biological communities through habitat transition from wetted to terrestrial conditions. The Njoro River, a tropical stream, was drought‐stressed between late 1999 and mid 2000, providing an opportunity to sample and describe the distributional patterns of diatoms and Limnodrilus oligochaetes in the vertical sediment profile. The dispersion of Limnodrilus oligochaetes with sediment depth profile varied from quasi‐random (i.e. exponent k of the negative binomial distribution >2.0 or <0) at the surface to strong aggregation (0 < k < 1.0) in the deeper sediments. Diatoms were heterogenous, with most species contributing less than 1% of all the diatoms collected from the riverbed. Contagious dispersion was a common feature among the diatom species. The distribution of Fragilaria ulna was largely quasi‐random in all sites, with Nitzschia amphibia and Cocconeis placentula demonstrating quasi‐random distribution in the Kerma vertical sediment profile. Escape from stranding to deeper sediment strata as the drought progressed was not a universal response among the diatom species. Our results showed that drought‐stress altered the structure of biological assemblages and also emphasized the need for the management of tropical lotic systems and their catchments for flow permanence. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Three new species of <Emphasis Type="Italic">Isospora</Emphasis> Schneider, 1881 (Apicomplexa: Eimeriidae) from the buffy-fronted seedeater <Emphasis Type="Italic">Sporophila frontalis</Emphasis> Verreaux (Passeriformes: Emberizidae) in South America

Three new coccidian (Apicomplexa: Eimeriidae) species from the buffy-fronted seedeater Sporophila frontalis Verraux in Brazil are reported in the current study. Isospora frontalis n. sp. oöcysts are spherical to sub-spherical, 27.9 × 26.9 μm, with a smooth, bi-layered wall c.1.4 μm thick. A micropyle and an oöcyst residuum are absent, but polar granules are present. Sporocysts are elongate ellipsoidal, 19.6 × 11.1 μm. The Stieda body is knob-like and the substieda body is slight. The sporocyst residuum is composed of scattered granules, and the sporozoites are vermiform with a refractile body and a nucleus. Isospora teresopoliensis n. sp. oöcysts are spherical to sub-spherical, 25.7 × 24.3 μm, with a smooth, bi-layered wall 1.3 μm thick. A micropyle, oöcyst residuum and polar granule are absent. Sporocysts are ovoid, 18.8 × 11.2 μm. The Stieda body is nipple-shaped and the substieda body is large and prominent. The sporocyst residuum is composed of scattered granules, and the sporozoites are large and elongate, with a refractile body and nucleus. Oöcysts of Isospora chanchaoi n. sp. are spherical to sub-spherical or ovoid, 24.2 × 22.0 μm, with a smooth, bi-layered wall c.1.2 μm thick. Both a micropyle and an oöcyst residuum are absent, but one or two polar granules are present. The sporocysts are ellipsoidal, 16.1 × 10.3 μm. The Stieda body is nipple-shaped and the substieda body is small but prominent. The sporocyst residuum forms a compact mass of granules, and the sporozoites are large and elongate, with a refractile body and a nucleus.     

Structure and evolution of the androecium in the Malvatheca clade (Malvaceae s.l.) and implications for Malvaceae and Malvales

Androecial development and structure as well as floral vasculature of six selected species of Bombacoideae and of several smaller lineages of the Malvatheca clade (Malvaceae s.l.) were studied. All studied taxa share a similar pattern of androecial development: initially, five antepetalous/antetepalous and five alternipetalous/alternitepalous primary androecial primordia develop on a ring wall. Two elongate secondary androecial primordia form on each antepetalous/antetepalous sector. At anthesis the androecium consists of an androecial tube crowned by five androecial lobes. Each of these lobes is the developmental product of an alternipetalous/alternitepalous primary androecial primordium and its two neighbouring antepetalous/antetepalous secondary androecial primordia. The elongate, sessile androecial units are positioned along the lateral margins of the androecial lobes and in the distal part of the androecial tube. Seen in the light of the most recent studies of floral development and phylogeny of the Malvaceae and the Malvales as a whole, our data indicate that i) elongate, sessile androecial units are ancestral in the Malvatheca clade, that ii) an obdiplostemonous floral ground plan is a synapomorphy for the Malvaceae, and that iii) diplostemony is most likely ancestral in the Malvales.     

Effect of lycopene on cell viability and cell cycle progression in human cancer cell lines

ABSTRACT: BACKGROUND: Lycopene, a major carotenoid component of tomato, has a potential anticancer activity in many types of cancer. Epidemiological and clinical trials rarely provide evidence for mechanisms of the compound's action, and studies on its effect on cancer of different cell origins are now being done. The aim of the present study was to determine the effect of lycopene on cell cycle and cell viability in eight human cancer cell lines. METHODS: Human cell lines were treated with lycopene (1-5 uM) for 48 and 96 h. Cell viability was monitored using the method of MTT. The cell cycle was analyzed by flow cytometry, and apoptotic cells were identified by terminal deoxynucleotidyl transferase-mediated dUTP nick labeling (TUNEL) and by DAPI. RESULTS: Our data showed a significant decrease in the number of viable cells in three cancer cells lines (HT-29, T84 and MCF-7) after 48 h treatment with lycopene, and changes in the fraction of cells retained in different cell cycle phases. Lycopene promoted also cell cycle arrest followed by decreased cell viability in majority of cell lines after 96 h, as compared to controls. Furthermore, an increase in apoptosis was observed in four cell lines (T-84, HT-29, MCF-7 and DU145) when cells were treated with lycopene. CONCLUSIONS: Our findings show the capacity of lycopene to inhibit cell proliferation, arrest cell cycle in different phases and increase apoptosis, mainly in breast, colon and prostate lines after 96 h. These observations suggest that lycopene may alter cell cycle regulatory proteins depending on the type of cancer and the dose of lycopene administration. Taken together, these data indicated that the antiproliferative effect of lycopene was cellular type, time and dose-dependent. KEY WORDS: lycopene, cancer, bioactive compounds, cell cycle.     

The serogroup B meningococcal outer membrane vesicle-based vaccine 4CMenB induces cross-species protection against Neisseria gonorrhoeae

There is a pressing need for a gonorrhea vaccine due to the high disease burden associated with gonococcal infections globally and the rapid evolution of antibiotic resistance in Neisseria gonorrhoeae (Ng). Current gonorrhea vaccine research is in the stages of antigen discovery and the identification of protective immune responses, and no vaccine has been tested in clinical trials in over 30 years. Recently, however, it was reported in a retrospective case-control study that vaccination of humans with a serogroup B Neisseria meningitidis (Nm) outer membrane vesicle (OMV) vaccine (MeNZB) was associated with reduced rates of gonorrhea. Here we directly tested the hypothesis that Nm OMVs induce cross-protection against gonorrhea in a well-characterized female mouse model of Ng genital tract infection. We found that immunization with the licensed Nm OMV-based vaccine 4CMenB (Bexsero) significantly accelerated clearance and reduced the Ng bacterial burden compared to administration of alum or PBS. Serum IgG and vaginal IgA and IgG that cross-reacted with Ng OMVs were induced by 4CMenB vaccination by either the subcutaneous or intraperitoneal routes. Antibodies from vaccinated mice recognized several Ng surface proteins, including PilQ, BamA, MtrE, NHBA (known to be recognized by humans), PorB, and Opa. Immune sera from both mice and humans recognized Ng PilQ and several proteins of similar apparent molecular weight, but MtrE was only recognized by mouse serum. Pooled sera from 4CMenB-immunized mice showed a 4-fold increase in serum bactericidal₅₀ titers against the challenge strain; in contrast, no significant difference in bactericidal activity was detected when sera from 4CMenB-immunized and unimmunized subjects were compared. Our findings directly support epidemiological evidence that Nm OMVs confer cross-species protection against gonorrhea, and implicate several Ng surface antigens as potentially protective targets. Additionally, this study further defines the usefulness of murine infection model as a relevant experimental system for gonorrhea vaccine development.     

Reproductive structures and phylogenetic framework of the rosids - progress and prospects

With ca 70.000 species the rosids contain more than a quarter of the total angiosperm species diversity. This taxonomic richness is reflected in a tremendous variety of floral organization and architecture. Rosids have received extensive molecular phylogenetic study. As a result, the monophyly and taxonomic composition of the group are well established. In addition, many subclades at the order level are now apparent. Deeper relationships, however, are still largely equivocal. As in many other parts of the plant tree of life, it will be impossible to reach an adequate understanding of the evolutionary history of the rosids without taking into account information from comparative morphological studies of extant and, in particular, also of fossil taxa. The fossil record of rosids is rich in well-preserved reproductive structures, and together with recent results from comparative studies of extant rosids, provides a wealth of floral structural data. Although much remains to be done at all levels, fresh attempts to synthesize and possibly reconcile results from molecular phylogenetics, comparative floral morphology, and palaeobotany, seem timely.     

The NorM efflux pump of Neisseria gonorrhoeae and Neisseria meningitidis recognizes antimicrobial cationic compounds

In Neisseria gonorrhoeae and Neisseria meningitidis, we identified a gene that would encode a protein highly similar to NorM of Vibrio parahaemolyticus (Y. Morita et al., Antimicrob. Agents Chemother. 42:1778-1782, 1998). A nonpolar insertional mutation in either the gonococcal or meningococcal norM gene resulted in increased bacterial sensitivity to compounds harboring a quaternary ammonium on an aromatic ring (e.g., ethidium bromide, acriflavine hydrochloride, 2-N-methylellipticinium, and berberine). The presence of point mutations within the -35 region of a putative norM promoter or a likely ribosome binding site resulted in an increased resistance of gonococci and meningococci to the same compounds, as well as to norfloxacin and ciprofloxacin. Structure-activity relationship studies with putative NorM substrates have found that a cationic moiety is essential for NorM recognition.     

Chronic Microdose Lithium Treatment Prevented Memory Loss and Neurohistopathological Changes in a Transgenic Mouse Model of Alzheimer's Disease

The use of lithium is well established in bipolar disorders and the benefits are being demonstrated in neurodegenerative disorders. Recently, our group showed that treatment with microdose lithium stabilized the cognitive deficits observed in Alzheimer’s disease (AD) patients. In order to verify the lithium microdose potential in preventing the disease development, the aim of this work was to verify the effects of chronic treatment with microdose lithium given before and after the appearance of symptoms in a mouse model of a disease similar to AD. Transgenic mice (Cg-Tg(PDGFB-APPSwInd)20Lms/2J) and their non-transgenic litter mate genetic controls were treated with lithium carbonate (1.2 mg/Kg/day in drinking water) for 16 or 8 months starting at two and ten months of age, respectively. Similar groups were treated with water. At the end of treatments, both lithium treated transgenic groups and non-transgenic mice showed no memory disruption, different from what was observed in the water treated transgenic group. Transgenic mice treated with lithium since two months of age showed decreased number of senile plaques, no neuronal loss in cortex and hippocampus and increased BDNF density in cortex, when compared to non-treated transgenic mice. It is suitable to conclude that these data support the use of microdose lithium in the prevention and treatment of Alzheimer’s disease, once the neurohistopathological characteristics of the disease were modified and the memory of transgenic animals was maintained.     

Floral bract function, flowering process and breeding systems ofSarcandra andChloranthus (Chloranthaceae)

Structure and function of floral bracts, anthesis and breeding systems were investigated in greenhouse plants ofSarcandra chloranthoides, Sarcandra glabra, andChloranthus spicatus (Chloranthaceae). In early developmental stages the floral bract replaces the lacking perianth as a protective structure by enclosing the floral organs completely in a pocket-like structure, which is formed by the u-shaped attachment zone of the floral bract to the spike axis. The floral bract has a tip with an epithem tissue, from which traces of secretion seem to be released by the stomata. All species investigated have protogynous and longlasting flowers. The female phase begins five to seven days earlier than the male phase. It continues during the male phase and for some time thereafter. The male phase lasts between one day (Chloranthus spicatus) and seven days (Sarcandra chloranthoides). This is the first study on breeding systems of Chloranthaceae. They are of special interest in such a basal family of the angiosperms. Although the investigatedSarcandra andChloranthus species have similar flowers with entomophilous features, surprisingly their breeding systems are diverse:Sarcandra glabra is self-compatible,S. chloranthoides is agamospermous andChloranthus spicatus is self-incompatible.     

Early Cretaceous floral structures and in situ tricolpate‐striate pollen: New early eudicots from Portugal

Five new taxa with affinities to extant lineages that diverged at an early stage from the main line of eudicot evolution are established from the Early Cretaceous (late Aptian or early Albian) Vale de Agua locality, Portugal. Staminate flowers of Lusistemon striatus and pistillate flowers of Lusicarpus planatus are unisexual without rudiments of the opposite gender. They are linked by the association of an unusual pollen type found in situ in the stamens and adhering to the stigmatic surface. The staminate flower, Lusistemon striatus, is composed of six stamens subtended by small perianth parts. The arrangement of the stamens is difficult to ascertain, but their variable sizes suggests a spiral arrangement. Pollen found in situ is tricolpate and striate with densely‐spaced, sparsely diverging and anastomosing muri that are aligned more or less parallel to the polar axis. The muri have a conspicuous supratectal ornamentation of fine transverse ridges. The granular infratectal layer forms an indistinct internal reticulum. The foot layer is thin. Pollen is closely similar to dispersed grains from the Aptian of Egypt described as STRIOTRI‐SEGMUR. It also resembles pollen of the dispersed pollen genus Rutihesperipites, as well as some dispersed pollen assigned to Striatopollis. Pistillate flowers of Lusicarpus planatus consist of a bicarpellate, syncarpous gynoecium borne on a short stalk. The styles are bent outwards and expose the double‐crested stigmatic regions on their ventral sides. The only organ preserved besides the gynoecium is a lateral scale‐like organ at the base of the stalk. Pollen of the same type found in Lusistemon striatus occurs on the stigmatic surface of the carpels. Comparisons with extant taxa demonstrate that Lusistemon and Lusicarpus share many characters with early diverging groups of eudicots, in particular Buxaceae. In addition to the Lusistemon‐Lusicarpus flowers, the Vale de Agua samples also contain three other pistillate reproductive structures that may be related to early diverging lineages of eudicots. Silucarpus camptostylus has a bicarpellate and syncarpous gynoecium with two styles; Valecarpus petiolatus and Aguacarpus hirsutus have tricarpellate gynoecia that are distinguished from each other in the shape and extension of the stigma as well as other details.