Gastrointestinal Helminths in Amietia sp. (Anura: Pyxicephalidae) from the Albertine Rift of Central Africa.

Fourteen Amietia sp. (Pyxicephalidae), from the Albertine Rift of Democratic Republic of the Congo were examined for helminths. Five species of Nematoda were found: Amphibiophilus chabaudi, Aplectana praeputialis, Falcaustra congoensis, Foleyellides duboisi and Orneoascaris chrysanthemoides. Amphibiophilus chabaudi was the most numerous nematode (n = 40) with the highest prevalence (57 %). Five new host records are reported.

Repeated evolution of digital adhesion in geckos: a reply to Harrington and Reeder.

We published a phylogenetic comparative analysis that found geckos had gained and lost adhesive toepads multiple times over their long evolutionary history (Gamble et al., PLoS One, 7, 2012, e39429). This was consistent with decades of morphological studies showing geckos had evolved adhesive toepads on multiple occasions and that the morphology of geckos with ancestrally padless digits can be distinguished from secondarily padless forms. Recently, Harrington & Reeder (J. Evol. Biol., 30, 2017, 313) reanalysed data from Gamble et al. (PLoS One, 7, 2012, e39429) and found little support for the multiple origins hypothesis. Here, we argue that Harrington and Reeder failed to take morphological evidence into account when devising ancestral state reconstruction models and that these biologically unrealistic models led to erroneous conclusions about the evolution of adhesive toepads in geckos.

Description of a new octoploid frog species (Anura: Pipidae: Xenopus) from the Democratic Republic of the Congo, with a discussion of the biogeography of African clawed frogs in the Albertine Rift.

We describe a new octoploid species of African clawed frog (Xenopus) from the Lendu Plateau in the northern Albertine Rift of eastern Democratic Republic of the Congo. This species is the sister taxon of Xenopus vestitus (another octoploid), but is distinguished by a unique morphology, vocalization and molecular divergence in mitochondrial and autosomal DNA. Using a comprehensive genetic sample, we provide new information on the species ranges and intra-specific diversity of African clawed frogs from the Albertine Rift, including the details of a small range extension for the critically endangered Xenopus itombwensis and previously uncharacterized variation in Xenopus laevis. We also detail a new method for generating cytogenetic preparations in the field that can be stored at room temperature for up to 3 weeks. While extending our understanding of the extant diversity in the Albertine Rift, this new species highlights components of species diversity in ancestral African clawed frogs that are not represented by known extant descendants.

Coming to America: multiple origins of New World geckos.

Geckos in the Western Hemisphere provide an excellent model to study faunal assembly at a continental scale. We generated a time-calibrated phylogeny, including exemplars of all New World gecko genera, to produce a biogeographical scenario for the New World geckos. Patterns of New World gecko origins are consistent with almost every biogeographical scenario utilized by a terrestrial vertebrate with different New World lineages showing evidence of vicariance, dispersal via temporary land bridge, overseas dispersal or anthropogenic introductions. We also recovered a strong relationship between clade age and species diversity, with older New World lineages having more species than more recently arrived lineages. Our data provide the first phylogenetic hypothesis for all New World geckos and highlight the intricate origins and ongoing organization of continental faunas. The phylogenetic and biogeographical hypotheses presented here provide an historical framework to further pursue research on the diversification and assembly of the New World herpetofauna.

Spatial characterization of electric potentials generated by pulsed microelectrode arrays.

This presentation is a report on the in situ characterization of stimulating microelectrodes in the context of multielectrode retinal prosthetic implants. The experimental system approximately replicates the geometric and electrical parameters of Second Sight Medical Products' Argus II Retinal Implant. Topographic maps of electric potentials have been prepared for a 60 electrode structure in which selected electrodes were stimulated with biphasic repetitively pulsed charge densities at 100 microC·cm(-2). Surface contour maps were prepared using a 10 microm diameter recording electrode.

Spatial distribution of the electric potential from photosystem I reaction centers in lipid vesicles.

Photosynthetic reaction centers are integral membrane complexes that produce a net transmembrane charge separation in response to light. The Photosystem I (PSI) complex is a thoroughly studied reaction center that has been proposed as a nanoscale photovoltaic structure in diverse applications, including activation of excitable cells by triggering of voltage-gated ion channels. An electrostatic model of a spherical lipid vesicle embedded with PSI and suspended in an aqueous medium is presented. The distribution of the electric potential is obtained by solving the nonlinear Poisson-Boltzmann equation with the finite-element method. The model predicts a maximum potential difference of 1.3 V between charges. This value depends mostly on the intrinsic dielectric constants of the reaction center and distance between charges. However, the potential distribution near the reaction center depends on the ionic strength of the aqueous medium. When the ionic strength is zero, the vesicle develops a transmembrane potential that increases linearly with the density of reaction centers. When the ionic strength increases, this potential difference approaches to zero. The main results of the simulations are consistent with previously reported experimental data. Based on the presented results, the potential application of PSI to light activation of voltage-gated ion channels is discussed.

Characterization of a single molecular QCA cell by Q-control enhanced amplitude modulation atomic force microscopy.

Major technical challenges for reduction of device sizes for computation and memory are the interconnection and power dissipation problems. Molecular quantum-dot cellular automata (QCA) have been proposed as solutions to this problem. Silicon phthalocyanine (SiPc) is a possible candidate for a molecular QCA element. Therefore, it is important to develop an in situ observation technique to visualize individual SiPc molecules. We report here the first image of a single SiPc dimer in air by using quality factor control (Q-control) enhanced amplitude modulation atomic force microscopy (AFM) and an investigation of the interaction forces between the tip and SiPc dimer. The AFM was operated at 0% relative humidity in an ultrapure nitrogen environment either with or without Q-control. Theoretical simulations using the point-mass description of the AFM, demonstrated that Q-enhancement reduced the force exerted from the tip to the sample surface. Our results, consistent with theory, demonstrated that the image force was reduced and a greater height and a larger size were measured. The advantages of this method can be extended to the AFM observation of other "soft" structures, and these results can be useful for a wider community.

Cranberry juice constituents affect influenza virus adhesion and infectivity.

Cranberry juice contains high molecular weight materials (NDM) that inhibit bacterial adhesion to host cells as well as the co-aggregation of many oral bacteria. Because of its broad-spectrum activity, we investigated NDM's potential for inhibiting influenza virus adhesion to cells, and subsequent infectivity. Hemagglutination (HA) of red blood cells (RBC) caused by representatives of both influenza virus A subtypes (H1N1)and H3N2) and the B type was inhibited by NDM at concentrations of 125 microg/ml or lower, which is at least 20-fold lower than that usually found in cranberry juice. A dose-response effect of NDM on HA was demonstrated. The infectivity of the A and B types was significantly reduced by preincubation with NDM (250 microg/ml), as reflected by the lack of cytopathic effect on Madine-Darby canine kidney (MDCK) cells and the lack of HA activity in the media of infected cells. The effect of NDM was also tested after A or B type viruses were allowed to adsorb to and penetrate the cells. Various levels of reduction in virus tissue culture infective dose TCID50 were observed. The effect was most pronounced when NDM was added several times to the infected MDCK cells. Our cumulative findings indicate that the inhibitory effect of NDM on influenza virus adhesion and infectivity may have a therapeutic potential.

Severe influenza infection in a chronic hepatitis C carrier: failure of protective serum HI antibodies after IM vaccination.

BACKGROUND: Influenza is an important cause of morbidity and mortality in immunocompromised hosts. Recommendations exists for vaccination each year, yet disease can still occur. OBJECTIVES: To describe the course of fulminant influenza infection in a patient with HCV. STUDY DESIGN: Case study in which correlation was made between immunoglobulin response to influenza vaccination to the disease and its unique clinical course caused by influenza virus. RESULTS: Influenza A/Jerusalem 17/98 (H(1)N(1)) was isolated from the throat of a chronic hepatitis C carrier who, presented with shortness of breath, and subsequent massive bilateral pneumonia. The patient was previously immunized IM with inactive influenza vaccine. He developed protective levels of humoral antibodies (1:80 hemagglutination inhibition (HI) antibodies) against the three strains of the vaccine that evidently did not prevent respiratory infection. The development of massive bilateral pneumonia and continued presence of influenza virus in the respiratory tract may have been due to his underlying medical condition and possible lack of mucosal secretory IgA (SIgA) antibodies. CONCLUSION: We have presented a case of prolonged influenza infection post vaccination. This case emphasizes the importance of an improved vaccine that would stimulate a better immunologic response, especially in immunocompromised patients.

Adolescent screening for orthopedic problems in high school.

BACKGROUND: The effectiveness of orthopedic screening programs for school-age children are still controversial. We conducted a prospective study in order to determine the frequency of undiagnosed orthopedic problems in an adolescent population. OBJECTIVE: To determine the frequency of undiagnosed orthopedic problems in an adolescent population discovered through routine physical examinations carried out by a general pediatrician in a school clinic. METHODS: We examined 2380 adolescents attending a public high school over a 5 y period in order to determine the frequency of undiagnosed orthopedic abnormalities in this age group. RESULTS: Previously undiagnosed orthopedic findings, especially spinal deformities were found in 14.8%. Scoliosis was detected in 1.6% of the entire group with a threefold predominance of girls over boys. Few cases were progressive and needed surgery. Extra spinal orthopedic findings were found in 2.9% of the patients. CONCLUSIONS: Screening programs can identify previously undetected orthopedic abnormalities in the school-age population. We conclude that screening programs for school age children coupled with subsequent follow-up procedures are worthwhile.

A novel liposomal influenza vaccine (INFLUSOME-VAC) containing hemagglutinin-neuraminidase and IL-2 or GM-CSF induces protective anti-neuraminidase antibodies cross-reacting with a wide spectrum of influenza A viral strains.

A liposomal influenza vaccine (INFLUSOME-VAC) was developed with the objective of overcoming the major drawbacks of the currently used influenza vaccines: their relatively low efficacy in certain high-risk groups (the elderly, infants, the immunosuppressed) and the need for annual immunization. INFLUSOME-VAC consists of liposomes containing the viral surface proteins hemagglutinin (HA) and neuraminidase (NA) derived from various influenza strains and IL-2 or GM-CSF, as an adjuvant. Vaccination of mice showed that, whereas conventional vaccines induced a low- and short-term response against HA and very low or no anti-NA response, INFLUSOME-VAC produced high titers of both anti-HA and anti-NA antibodies (Abs) in young and old mice that persisted for at least 6 months. Moreover, the anti-NA Abs efficiently cross-reacted with several N2 viral subtypes spanning 20 years, and such vaccines afforded partial protection against heterosubtypic viral infection.

Stand-off tissue-based biosensors for the detection of chemical warfare agents using photosynthetic fluorescence induction.

Tissue biosensors made from immobilized whole-cell photosynthetic microorganisms have been developed for the detection of airborne chemical warfare agents and simulants. The sensor read-out is based on well-known principles of fluorescence induction by living photosynthetic tissue. Like the cyanobacteria and algae from which they were constructed, the sensors are robust and mobile. The fluorescence signal from the sensors was stable after 40 days, storage and they can be launched or dropped into suspected danger zones. Commercially available hand-held fluorometric detector systems were used to measure Photosystem II (PSII) photochemical efficiency of green algae and cyanobacteria entrapped on filter paper disks. Toxic agents flowing in the gas stream through the sensors can alter the characteristic fluorescence induction curves with resultant changes in photochemical yields. Tabun (GA), sarin (GB), mustard agent, tributylamine (TBA) (a sarin stabilizer), and dibutyl sulfide (DBS) (a mustard agent analog) were tested. Upper threshold limits of detectability for GA, TBA, and DBS are reported. With additional research and development, these biosensors may find application in stand-off detection of chemical and perhaps biological warfare agents under real-world conditions.

Serum and mucosal immunologic responses in children following the administration of a new inactivated intranasal anti-influenza vaccine.

Children are at considerable risk for influenza infection and may constitute the main vector for transmitting the virus to adults in the community. At present, the use of available vaccines in children is limited mainly because of a fear of side effects from the injection. Intranasal immunization was assessed as a painless, side effect-free method of facilitating the enrollment of children in vaccination programs. One intranasal dose of a trivalent inactive whole virus vaccine containing 20 microg of the three recommended seasonal viral strains was administered to 28 children recruited over two separate winter periods (1997/1998 and 1998/1999). No adverse effects were recorded. Serum IgG responses were determined by the hemagglutination inhibition (HI) method and nasal IgA responses by enzyme-linked immunosorbent assay (ELISA). In both study period seasons, 77.7%-94.4% of children were found to be immune. There was a 3.7 x and 4.7 x increase in geometric mean titer (GMT) for A/H3N2 strains, 1.9 x and 3.9 x for A/H1N1 strains, and a 3.2 x and 1.7 x for B strains in 1997/1998 and 1998/1999, respectively. The increase in GMT, as well as fourfold increases in titer level, was higher when calculated among the nonimmune children prior to vaccination. Of these, 50%-87.5% became immune following immunization. Local antibody response to the three viral strains was detected in 50%-55% of the immunized children. Also, 83.3%, 73.3%, and 61.1% of the vaccinees exhibited a mucosal and/or serum antibody response to the A/Beijing, A/Sydney, and B/Harbin strains, respectively. This mucosal response may forestall influenza development in its early stages, thereby contributing significantly to the reduction of influenza spread in the community.

Sexual differentiation in the spiny softshell turtle (Apalone spinifera), a species with genetic sex determination.

It is hypothesized on the basis of sex determination theory that species exhibiting genetic sex determination (GSD) may undergo sexual differentiation earlier in development than species with environmental sex determination (ESD). Most turtle species exhibit a form of ESD known as temperature-dependent sex determination (TSD), and in such species the chronology of sex differentiation is well studied. Apalone spinifera is a species of softshell turtle (Trionychidae) that exhibits GSD. We studied sexual differentiation in this species in order to facilitate comparison to TSD species. Eggs were incubated at two different temperatures and embryos were harvested at various stages of mid to late development. Gonad length was measured with image analysis software, then prepared histologically. Indifferent gonads have differentiated in stage 19 embryos. Histological details of gonadogenesis follow the same pattern as described for other reptiles. Regression of the male paramesonephric duct closely follows testicular differentiation. Gonad lengths are longer at the warmer incubation temperature, and ovaries are generally longer than testes at each stage and for each temperature. Although sexual differentiation takes place at about the same stage as in other turtles with TSD (18-20), in A. spinifera this differentiation is irreversible at this stage, while in some of the TSD species sex is reversible until about stage 22. This immutable, definitive sexual differentiation may support the hypothesis of an accelerated chronology of sex differentiation for this species. We also note that sexual dichromatism at hatching is known in this species and may provide additional evidence of early differentiation. J. Exp. Zool. 290:190-200, 2001.

Nanoscale photosynthesis: photocatalytic production of hydrogen by platinized photosystem I reaction centers.

A study of the photocatalytic production of molecular hydrogen from platinized photosystem I (PSI) reaction centers is reported. At pH 7 and room temperature metallic platinum was photoprecipitated at the reducing end of PSI according to the reaction, [PtCl6]2- + 4e- + hv-->Pt decreases + 6Cl-, where it interacted with photogenerated PSI electrons and catalyzed the evolution of molecular hydrogen. The reaction mixture included purified spinach PSI reaction centers, sodium ascorbate and spinach plastocyanin. Experimental data on real-time catalytic platinum formation as measured by the onset and rates of hydrogen photoevolution as a function of time are presented. The key objective of the experiments was demonstration of functional nanoscale surface metalization at the reducing end of isolated PSI by substituting negatively charged [PtCl6]2- for negatively charged ferredoxin, the naturally occurring water-soluble electron carrier in photosynthesis. The data are interpreted in terms of electrostatic interactions between [PtCl6]2- and the positively charged surface of psaD, the ferredoxin docking site situated at the stromal interface of the photosynthetic membrane and which is presumably retained in our PSI preparation. A discussion of the rates of hydrogen evolution in terms of the structural components of the various PSI preparations as well as of those of the intact thylakoid membranes is presented.

A double-blind trial of a new inactivated, trivalent, intra-nasal anti-influenza vaccine in general practice: relationship between immunogenicity and respiratory morbidity over the winter of 1997-98.

BACKGROUND: Influenza is responsible for considerable morbidity not only among older people but in younger age groups as well. However, most large-scale anti-influenza vaccination campaigns are still aimed principally at the elderly using injectable vaccines. Until now there has been much less emphasis on targeting younger populations or using intra-nasal vaccines in mass anti-influenza immunisation programmes. OBJECTIVES: To assess the immunogenicity of a new inactivated intra-nasal anti-influenza vaccine and to measure its effect on respiratory morbidity in a volunteer general practice population. STUDY DESIGN: A prospective, double-blind, placebo-controlled trial using the new vaccine was carried out over the winter of 1997-98 on 274 healthy patients aged 12-60 from three Israeli general practices, 182 in the vaccine group and 92 in the placebo group. Following vaccination the changes in the antigen levels and episodes of respiratory illness in the vaccine and placebo groups were measured. RESULTS: Protective antibody levels occurred after a single dose of vaccine [influenza H1N1, 41% immune pre-vaccination to 73% post-vaccination; influenza H3N2, 35-66%; influenza B, 27-64%]. Between January and March 1998, when influenza activity was at a peak in Israel, the average number of respiratory illness events in the vaccine group [14 events/100 subjects per month] was significantly less than in the placebo group [22 events/100 subjects per month]; similarly, the average number of respiratory illness days in the vaccine group over the same period [69 days/100 subjects per month] was significantly less than in the placebo group [117 days/100 subjects per month]. CONCLUSIONS: The new vaccine possessed significant immunogenicity and was associated with a significant reduction in respiratory morbidity among a group of healthy older children and adults. Since intra-nasal vaccines are simpler to administer and more acceptable to the public than injections the vaccine's potential for use in routine anti-influenza vaccination campaigns seems promising, especially if its beneficial effects are also reproducible in more medically vulnerable populations.

Microalgae: a green source of renewable H(2).

This article summarizes recent advances in the field of algal hydrogen production. Two fundamental approaches are being developed. One involves the temporal separation of the usually incompatible reactions of O(2) and H(2) production in green algae, and the second involves the use of classical genetics to increase the O(2) tolerance of the reversible hydrogenase enzyme. The economic and environmental impact of a renewable source of H(2) are also discussed.

Local and systemic immune response in community-dwelling elderly after intranasal or intramuscular immunization with inactivated influenza vaccine.

Intramuscular (IM) influenza vaccines are about 50% effective in preventing clinical illness among the elderly and their effectiveness in eliciting mucosal response may be even lower. The aim of the present study was to evaluate the immunological effect of a novel inactivated intranasal (IN) trivalent whole influenza virus vaccine among community-dwelling elderly. Sixty-one subjects were vaccinated with two doses of an IN vaccine and a control group of 31 subjects was vaccinated with a commercial IM vaccine. Viral strains in the 1997/8 vaccine used were A/Nanchang/933/95(H3N2), A/Johannesburg/82/96(H1N1) and B/Harbin/7/94. Serum IgG and nasal IgA were determined by HI and ELISA, respectively. Only a few minor local adverse events were reported after vaccination. Seroconversion for the three antigens tested was higher after IM vaccination, although not statistically significant. Local antibody response to the three antigens tested was detected in 50-53% and 19-26% of IN and IM immunized subjects, respectively. The IN vaccine tested was significantly more effective than the IM vaccine in inducing mucosal IgA response. This may prevent influenza at its early stages and thus contribute to the reduction of complications in the elderly.