Visual pigments in a living fossil,the Australian lungfish <Emphasis Type="Italic">Neoceratodus forsteri</Emphasis>

Background  

One of the greatest challenges facing the early land vertebrates was the need to effectively interpret a terrestrial environment. Interpretation was based on ocular adaptations evolved for an aquatic environment millions of years earlier. The Australian lungfish Neoceratodus forsteri is thought to be the closest living relative to the first terrestrial vertebrate, and yet nothing is known about the visual pigments present in lungfish or the early tetrapods.     

Acute toxicity effects of ibuprofen on behaviour and haematological parameters of African catfish Clarias gariepinus (Burchell, 1822)

Indiscriminate discharge of pharmaceutical waste into the aquatic ecosystem may pose serious health challenges to aquatic biota. The effect of acute exposure to ibuprofen was evaluated using changes in behaviour and haematological parameters under static bio-assay method in Clarias gariepinus. Test specimens were exposed to acute concentrations of ibuprofen (0.28, 0.33, 0.38, 0.43 and 0.48 mg l^?1) for 24, 48, 72 and 96 h durations respectively. Behavioural and phenotypic changes were observed in surviving fish. There were significant (p < 0.05) concentration and duration-dependent increases in erythrocyte (RBC), haemoglobin (Hb), pack cell volume (PCV) and leukocytes (WBC) in treated fish compared to the control. Insignificant decreases (p > 0.05) in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were observed in treated fish compared to the control. Ibuprofen elicited dose and duration- dependent decrease in neutrophil counts with the decreases being significant (p < 0.05) in the higher doses of 0.43 and 0.48 mg l^?1. Ibuprofen did not elicit any significant changes in monocytes, basophils and eosinophils. Changes observed in this study showed that ibuprofen negatively affected the health of the fish and we recommend that discharge of ibuprofen into the aquatic environment should be monitored and controlled.     

The composition of the incubation medium influences the sensitivity of mitochondrial permeability transition to cyclosporin A

The aim of this work was to study permeability transition, and the influence of the composition of the incubation medium, on the inhibitory action of cyclosporin A. It was found that cyclosporin inhibited the opening of a nonspecific pore, as induced by the uncoupler carbonyl cyanide m-chlorophenylhydrazone, provided K⁺ was present in the incubation medium, but failed to do so if mitochondria are incubated in sucrose or Na⁺-based medium. It was also found that the sensitivity of mitochondria to the uncoupler depended on the incubation mixture, being more sensitive when sucrose was the osmotic support. Matrix Ca²⁺ release, large amplitude swelling, and drop in transmembrane electric gradient revealed permeability transition. The titration of membrane thiol groups shows them to be increased in mitochondria incubated in sucrose medium, in comparison with the values found in mitochondria incubated in KCl or NaCl medium. Our proposal is that the incubation in sucrose medium propitiated a conformational change of membrane proteins in such a way that cyclosporin was unable to bind to its target site.     

A synopsis of <Emphasis Type="Italic">Cohniella</Emphasis> (Orchidaceae,Oncidiinae)

A synopsis of the genus Cohniella is presented with nomenclatural updates with a discusion of diagnostic features and biogeographical data. Thirteen species and one natural hybrid are recognized. Two new species, Cohniella pendula and Cohniella biorbicularis, are described and illustrated. The following four new combinations are proposed: Cohniella binotii, Cohniella brachyphylla, Cohniella cepula, and Cohniella longifolia. Lectotypes are selected for Oncidium subulifolium, Oncidium helicanthum, Oncidium humboldtii, Oncidium jonesianum var. phaeanthum, Oncidium cepula, and Oncidium wittii. We also propose an amended lectotype for Epidendrum cebolleta and several epitypifications and new synonyms. A key to the genera of the Trichocentrum complex is presented (Appendix) as well as keys to the species of Cohniella.     

A new nothogenus and nothospecies in the Oncidiinae (Orchidaceae) from Quintana Roo,Mexico

We propose the new nothogenus, ×Cohnlophiaris Cetzal & Balam (Cohniella×Lophiaris) based on a natural intergeneric hybrid, ×Cohnlophiaris quintanarooensis Cetzal & Carnevali (Cohniella ascendens×Lophiaris oerstedii) from a locality in Quintana Roo, Mexico, which is here described and illustrated. The new nothospecies is vegetatively similar to C. ascendens but the flowers show intermediate characters between the putative parents. ×Cohnlophiaris quintanarooensis is similar to C. ascendens by having yellow petals and sepals with brown or reddish spots, transversely subquadrate central lobe, central keel parallel to the proximal and distal teeth, and pollinarium of Cohniella type. On the other hand, is it similar to L. oerstedii in the papillose abaxial surface of petals and sepals, the oblong lateral lobes of the labellum, the subquadrate column base, the pentagonal cavity stigmatic and the pink clinandrium. A key to diagnose the new intergeneric hybrid and its putative parents, a comparative figure and a map showing their geographical distribution are provided.     

An alternative supporting electrolyte for enzyme immobilization in conducting polymers

In this study an alternative supporting electrolyte was used in enzyme immobilization. Invertase was studied to observe the effect of the supporting electrolyte. Sulfonated poly(arylene ether sulfone) was used as the supporting electrolyte during the electrolysis of pyrrole. The results show that the polymeric supporting electrolyte can be used instead of sodium dodecyl sulfate.     

Tetranucleotide,trinucleotide, and dinucleotide loci from the bobcat (Lynx rufus)

We describe primers and polymerase chain reaction (PCR) conditions to amplify four dinucleotide, one trinucleotide, and three tetranucleotide microsatellite DNA loci from the bobcat (Lynx rufus). The primers were tested on 22 individuals collected from a population located within southwestern Georgia (USA). The primer pairs developed in this study yielded an average of 7.4 alleles per locus (range four to 10), an average observed heterozygosity of 0.60 (range 0.40 to 0.76), and an average polymorphic information content of 0.70 (range 0.51 to 0.78).     

Phytolaccaceae infructescence from Cerro del Pueblo Formation, Upper Cretaceous (late Campanian), Coahuila, Mexico

The Upper Cretaceous (late Campanian) Cerro del Pueblo Formation, Coahuila, Mexico, contains a diverse group of angiosperms represented mainly by their reproductive structures. Among these, a new permineralized infructescence is recognized based on its morphological and anatomical characters. It is a multiple infructescence composed of berry fruits with six locules, each containing a single seed with a curved embryo developed from a campylotropous ovule with pendulous placentation; integumentary anatomy is similar to that of Phytolacca spp. (Phytolaccaceae). Though this new plant from Coahuila shares reproductive characters with Phytolacca, the constant number (six) of carpels per fruit and pendulous placentation strongly support the recognition of a new taxon, Coahuilacarpon phytolaccoides Cevallos-Ferriz, Estrada-Ruiz, et Pérez-Hernández (Phytolaccaceae, Caryophyllales). This new record adds to the known plant diversity of low latitude North America (northern Mexico) and demonstrates the long geologic history of the group.     

CSP—A Model for In Vivo Presentation of Plasmodium berghei Sporozoite Antigens by Hepatocytes

One target of protective immunity against the Plasmodium liver stage in BALB/c mice is represented by the circumsporozoite protein (CSP), and mainly involves its recognition by IFN-γ producing specific CD8+T-cells. In a previous in vitro study we showed that primary hepatocytes from BALB/c mice process Plasmodium berghei (Pb) CSP (PbCSP) and present CSP-derived peptides to specific H-2k^d restricted CD8+T-cells with subsequent killing of the presenting cells. We now extend these observations to an in vivo infection model in which infected hepatocytes and antigen specific T-cell clones are transferred into recipient mice inducing protection from sporozoite (SPZ) challenge. In addition, using a similar protocol, we suggest the capacity of hepatocytes in priming of naïve T-cells to provide protection, as further confirmed by induction of protection after depletion of cross-presenting dendritic cells (DCs) by cytochrome c (cyt c) treatment or using traversal deficient parasites. Our results clearly show that hepatocytes present Plasmodium CSP to specific-primed CD8+T-cells, and could also prime naïve T-cells, leading to protection from infection. These results could contribute to a better understanding of liver stage immune response and design of malaria vaccines.     

Lifetable demography and population growth of the rotifer Brachionus angularis in Kenya: influence of temperature and food density

Lifetable demography and reproductive traits of a Kenyan strain of the rotifer Brachionus angularis were investigated using individual and small batch culture approaches. The rotifer was identified morphologically before conducting studies at 20, 25 and 30 °C, using Chlorella vulgaris at 2.5 × 10⁵ to 2.5 × 10⁷ cells ml^–1. The rotifers were highly fecund, producing 2.11 ± 0.07 offspring female^–1 day^–1 and reproductive, producing 8.43 ± 0.24 offspring female^–1 at 25 °C with 2.5 × 10⁶ algal cells ml^–1. The highest intrinsic rate of natural increase (0.74 ± 0.02 d^–1), specific population growth rate (0.49 ± 0.01), longest life expectancy at hatching (12.41 ± 0.28 d) and shortest generation time (2.87 ± 0.03 d) also occurred at 25 °C with 2.5 × 10⁶ algal cells ml^–1. The duration of hatching to first spawning was shortest (2.86 ± 0.21 h) at 30 °C with 2.5 × 10⁷ algal cells ml^–1 and longest (8.83 ± 0.39 h) at 20 °C with 2.5 × 10⁵ algal cells ml^–1. The highest population density (255.7 ± 12.6 ind. ml^–1) was realised at 25 °C with 2.5 × 10⁶ cells ml^–1 on Day 8, whereas the lowest population density (122.0 ± 3.6 ind. ml^–1) was realised at 20 °C with 2.5 × 10⁵ cells ml^–1 on Day 8. The lorica length and width of the Kenyan strain of B. angularis are 85.6 ± 3.1 µm and 75.4 ± 3.6 µm, respectively. The rotifer optimally reproduces at 25 °C when fed with 2.5 × 10⁶ algal cells ml^–1.