At Palmyra Atoll,the fish-community environmental DNA signal changes across habitats but not with tides

At Palmyra Atoll, the environmental DNA (eDNA) signal on tidal sand flats was associated with fish biomass density and captured 98%–100% of the expected species diversity there. Although eDNA spilled over across habitats, species associated with reef habitat contributed more eDNA to reef sites than to sand-flat sites, and species associated with sand-flat habitat contributed more eDNA to sand-flat sites than to reef sites. Tides did not disrupt the sand-flat habitat signal. At least 25 samples give a coverage >97.5% at this diverse, tropical, marine system.     

Aquatic biodiversity and saline lakes: Lake Bogoria National Reserve,Kenya

Lake Bogoria, in the Rift Valley of Kenya is an extreme saline lake (conductivity 40–80 mS cm^–1, alkalinity 1500 m equ l^–1). It is hydrologically more stable than the other, endorheic lakes in Kenya, because it is deep – maximum depth at present just over 10 m in an area of 3000 ha – and so does not have periods when it is dry. It is ecologically simple, with only one species dominating the phytoplankton – the cyanobacterium `spirulina', Arthrospira fusiformis. Its biomass and productivity were very high – biomass between 38 and 365 g l<sup>–1</sup> chlorophyll `a' and 3.4–21 × 10³ coils ml^–1 and net production between 0.24 and 1 gm C m³ h, the latter in a narrow zone of less than a metre. There were no macro-zooplankton in the plankton and the only grazer of A. fusiformis was the lesser flamingo, Phoeniconaias minor,which occurred irregularly in very high concentrations (in excess of 1 × 10⁶). Detritivory in the benthos was effected by a single chironomid species, Paratendipes sp., at a maximum density of 4 × 10⁴ m^–2. The mean daily emergence of adult chironomids was estimated to be 1 × 10³ m^–2, the maximum 3. There was no littoral plant community within the lake but 44 dicotyledonous and 31 monocotyledonous plant species in the drawn-down zone and adjacent to it. A diverse draw-down terrestrial invertebrate fauna, only superficially described here, processed the flamingo feathers and carcasses, with other detritus such as chironomid pupal exuviae and decaying A. fusiformis scum. About 50 bird species depended upon the chironomids, either as they emerged through the water column as flying adults or later on the shoreline as floating pupal exuvia and dead adults. The lake has high conservation value because of three bird species in particular – lesser flamingo, Cape teal and black-necked grebe. The former provides real economic value in a region otherwise impoverished, because of the spectacle of tens of thousands of flamingos set against the landscape of hot springs and fumaroles at the lake edge, which draws 15000 visitors per annum. P. minor has experienced three periods during the past ten years when major mortalities have occurred, the last of which killed 700 birds day^–1. This could have involved as many as 200000 birds (about 1/5th of the maximum population at this lake) if mortality was at a constant rate for the nine months it was observed. Causes of mortality have been suggested as avian tuberculosis, poisoning from cyanobacterial toxins or from heavy metal contamination at Lake Nakuru, but it is still not yet clear what contribution each makes to the problem.     

Oxygen-binding Heme Complexes of Peptides Designed to Mimic the Heme Environment of Myoglobin and Hemoglobin

Development of effective resuscitation agents for blood-loss replacement in trauma or surgery is extremely important despite substantial improvements in screening methods of blood from human donors. This paper reports the design and synthesis of peptides that mimic the natural environment of the heme group in myoglobin (Mb) and in the - and -subunits of human adult hemoglobin (Hb). The designs were based on the fact that the heme group in the aforementioned proteins is sandwiched between helices E and F. Fifteen test peptides and six control peptides were synthesized, and their ability to form stable complexes with heme was investigated. It was found that none of the control peptides or proteins was able to bind heme. However, each of the peptides that were designed to mimic the E--F helices, and even shorter designs, which removed from this region residues that do not contribute to contacts with the heme group, were each able to bind one mole of heme per mole of peptide forming peptide–heme complexes that were stable to manipulation and behaved as single molecular species. Oxygen binding measurements on the reduced peptide–heme complexes showed that these compounds bind oxygen and give visible spectra that were typical of oxygenated heme-proteins. In oxygen binding measurements done under different partial pressures of oxygen, the heme–peptide complexes gave hyperbolic oxygen-saturation curves, but showed slight differences in their P₅₀ values. The P₅₀ values ranged from 3.8 mmHg for the heme–peptide B7 complex to 13.7 mmHg for the heme–peptide D13 complex (under the same conditions, P₅₀ values for Hb and Mb were 34.0 and 5.5 mmHg, respectively). It is concluded that peptide constructs designed to mimic the heme-binding regions of Mb or the Hb subunits were able to form coordinate 1:1 complexes with heme, and these complexes bind oxygen in a manner expected for single subunit heme proteins.     

Detection and analysis of six lizard adenoviruses by consensus primer PCR provides further evidence of a reptilian origin for the atadenoviruses

A consensus nested-PCR method was designed for investigation of the DNA polymerase gene of adenoviruses. Gene fragments were amplified and sequenced from six novel adenoviruses from seven lizard species, including four species from which adenoviruses had not previously been reported. Host species included Gila monster, leopard gecko, fat-tail gecko, blue-tongued skink, Tokay gecko, bearded dragon, and mountain chameleon. This is the first sequence information from lizard adenoviruses. Phylogenetic analysis indicated that these viruses belong to the genus Atadenovirus, supporting the reptilian origin of atadenoviruses. This PCR method may be useful for obtaining templates for initial sequencing of novel adenoviruses.     

PLEUROPULMONARY AMEBIASIS

Pleuropulmonary amebiasis may be manifest without diarrhea or dysentery.In obscure lesions of the right lower lung field, one should always consider pleuropulmonary amebiasis—especially with low grade fever and moderate leukocytosis.Abscess and empyema contents should be examined promptly microscopically or kept warm to preserve the motility of the trophozoites until satisfactory examination is possible.Conservative therapy will successfully manage most cases of pleuropulmonary amebiasis.If a thorough search fails to reveal Entameba histolytica, and the diagnosis is still entertained, a medical therapeutic trial is in order.     

Morphological divergence within and between the Mexican sailfin mollies, Poecilia velifera and Poecilia petenensis

This study examined the patterns of morphological variation both between species, and between sexes and among populations within each species of the Mexican sailfin mollies, Poecilia velifera and Poecilia petenensis , using geometric morphometrics and linear measurements of morphological traits. While sexes within each species differed in characteristics that may be important in sexual selection, such as length of the dorsal fin, species differed in traits, such as body depth, that may also be influenced by natural selection due to differences in habitats. Within each species, many morphological traits were similar among populations, but important differences, including caudal peduncle depth in P. petenensis (but not in P. velifera ), suggested that habitat differences may also be important in shaping population divergence independently within each species. Indeed, the evolutionary vectors of male morphological population divergence for each species differed by an angle of 98·5°, representing nearly orthogonal vectors and suggesting independent shape divergence between these two molly species. Finally, geographic isolation did not explain the morphological differentiation seen among populations, suggesting that natural and sexual selection were strong forces promoting morphological diversification within these two species, despite the potential for a high degree of population connectivity and gene flow.