Western equine and St. Louis encephalitis in man,California, 1945-1950

A large group of etiologic agents, some known and some unknown, produce in man a clinical syndrome now labeled "infectious encephalitis."The separation, from this larger group, of single disease entities which cause similar clinical symptoms is possible, but calls for diagnostic acumen plus supporting laboratory evidence. Two etiologically specific entities, western equine encephalitis and St. Louis encephalitis, are frequently encountered in rather well-defined areas of California, the Central Valley and Imperial Valley; and there is a definite seasonal pattern of occurrence-June through October. There are certain guides that are helpful in differential diagnosis. Establishing a diagnosis on the basis of clinical evidence is difficult. Laboratory studies are of great importance not only for diagnosis in the individual case but for advancement of etiology. Specimens are worthless unless taken at proper intervals and submitted by methods described. It is probable that encephalitides caused by still unknown agents exist in California. The isolation and identification of new encephalitogenic viral agents will depend in large measure upon the submission by physicians of suitable specimens from patients with central nervous system disease in which the cause is obscure.     

Lichens of St Helena and Ascension Island

Lichens are the dominant organisms on most of the South Atlantic island of St Helena. In total, 220 different species were found during a recent survey, most of which have never been reported from the island. Previously, less than 50 lichen species were reported from the island, one half of which are most probably incorrect records. The total number of lichens known from the island now stands at 225. Most species could be identified, but the following, most probably endemic, species are described as new to science: Dolichocarpus seawardii , which is only the second species in this genus, the type being from Chile; Dermatiscum pusillum , which is only the third species in this African genus; Dimelaena triseptata ; Xanthoparmelia beccae ; and four Ramalina species, Ramalina geniculatella , R. ketner‐oostrae , R. rigidella , and R. sanctae‐helenae . The lichen flora has many species in common with that of the geologically much younger Ascension Island, where just under 100 species were recently found by the author, most of which are equally new to that island. Lecanora sanctae‐helenae, previously known as the only endemic lichen of St Helena, was also found to be abundant on Ascension Island. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 147–171.     

Comparison of molecular and morphological data on St Helena: Elaphoglossum

The endemic elaphoglossoid ferns, Elaphoglossum dimorphum, E. nervosum and Microstaphyla furcata of St Helena, form a closely related group within section Lepidoglossa when analysed phylogenetically using sequences from the chloroplast trnL intron (partial) and trnL-F intergenic spacer. Microstaphyla furcata, traditionally placed in its own genus, is clearly shown to belong to Elaphoglossum confirming the previous transfer of this species to Elaphoglossum as E. bifurcatum. There is hardly any trnL-F sequence divergence between the species, in fact sequences of E. nervosum and E. dimorphum are identical. These results are consistent with the possible origin of E. dimorphum as a hybrid between E. bifurcatum and E. nervosum or with the view that the three species are the result of a recent radiation. The potential conflict between phylogenetic and morphological distinctness in determining species conservation priorities is discussed.     

Bryophytes of St Helena,South Atlantic Ocean. 8. Lepidopilidium crispifolium,sp. nov. (Hookeriales,Pilotrichaceae)

Abstract

A new species of Lepidopilidium (Pilotrichaceae, Hookeriales), L. crispifolium, sp. nov. from St Helena, South Atlantic Ocean is described and illustrated.     

Relationships and genetic diversity of endemic Elaphoglossum from St Helena

Allozyme polymorphism was used 1) to investigate the relationships of three threatened species of Elaphoglossum from St Helena, E. nervosum, E. bifurcatum and E. dimorphum, and 2) to estimate levels of genetic diversity and its partitioning among populations. Despite showing morphological and ecological variation, the three species are closely related with high genetic identities. Evidence from one enzyme locus (Mdh-1) suggests that E. dimorphum is of hybrid origin involving E. nervosum and E. bifurcatum. Levels of genetic diversity were low in the three species, but comparable with other insular endemic angiosperms. Populations of E. nervosum and E. bifurcatum showed significant genetic differentiation, which should be taken into account in any conservation programme.     

Diversity and Characterization of Culturable Fungi from Marine Sediment Collected from St. Helena Bay, South Africa

Marine fungi are known to originate from a wide variety of habitats within the marine environment. Marine sediment represents one environmental niche, with most fungi occurring in these sediments being facultative marine fungi with terrestrial origins. It has not been proven whether these fungi merely survive the harsh environmental conditions presented by the ocean sediment, as opposed to playing an active role in this ecological niche. During this study, marine sediment was collected from St. Helena Bay, on the west coast of the Western Cape, South Africa. Using dilution, enrichment, and repetitive culturing techniques, 59 fungal isolates were obtained from marine sediments and identified to at least genus level using morphological and molecular methods. Moreover, a series of tests were performed to characterize the physical and physicochemical attributes of the isolates. Results showed that the isolates not only survived but also had the potential to grow in the natural conditions present in this environment. Extracellular cellulase was produced by the filamentous fungal isolates indicating their probable role in detrital decay processes and therefore the carbon cycle on the ocean bed. Also, denitrification patterns were observed when isolates were grown in liquid media amended with NaNO(2), NaNO(3), and (NH(4))SO(4), implicating that these fungi have the potential to play an active role in denitrification, co-denitrification, and ammonification phases of nitrogen cycles occurring in the marine sediments.     

No overall benefit of predator exclosure cages for the endangered St. Helena Plover Charadrius sanctaehelenae

Predator exclosure cages are designed to increase the clutch survival of ground‐nesting birds. Predator exclosures provided for the endangered St. Helena Plover Charadrius sanctaehelenae, however, did not result in differences in clutch survival between protected and control nests and may have resulted in elevated adult mortality. Exclosures did not exclude all cats, the dominant nest predator, and it is likely that cats caused the adult mortalities observed close to the exclosures. A population model indicates that even if predator exclosures had excluded all cats, the benefits of increased clutch survival would have been more than negated by the estimated decrease in adult survival. The overall effect of predator exclosures needs to be clarified for other species, taking into consideration annual productivity and adult survival, to understand the circumstances in which predator exclosures are beneficial.     

Growth rates and agar properties of three gracilarioids in suspended open-water cultivation in St. Helena Bay, South Africa

Relative growth rates (RGRs), yields and agar characteristics of threegracilarioid isolates (Gracilariopsis sp. from St. Helena Bay, and Gracilaria gracilis isolates from Langebaan Lagoon and Saldanha Bay) weremeasured to assess the suitability of a site in St. Helena Bay for suspendedcultivation. The gracilarioids were grown on polypropylene ropes and`netlon' lines, and the RGRs were 4.0–11.0% d<sup>-1</sup> and 5.0–7.0%d<sup>-1</sup>, respectively. The RGR of the Langebaan isolate of G. gracilis grown on ropes was significantly higher than the RGR of otherisolates. The mean net yield for the Langebaan isolate grown on `netlon'lines was 2.6 ± 0.9 kg wet wt m^-2 30 day^-1. Thecultured gracilarioids were extracted for native and alkali treated agars. Themean native agar yield over the entire period was 39.0% dry wt. Alkalipretreatment reduced the yield by 55%, but significantly increased gelstrength. High gel strengths (>750 g cm^-2) were measured inagars from Gracilariopsis sp. and Saldanha Gracilaria gracilis inmid-summer and winter. The dynamic gelling and melting temperatures ofnative and alkali treated agars varied among the gracilarioids. The meangelling and melting temperatures of agars were about 39.0 ^°C and86.0 ^°C, respectively. The 3,6-AG content ranged from 29% to38% for native agars and 34–45% for alkali treated agars. While theseresults indicate that this site is suitable for gracilarioid cultivation, occasionallow-oxygen events in St. Helena Bay lead to production of hydrogensulphide in the sea water (`black tides'). Such events killed most inshorebiota (including seaweeds) in 1994 and 1998. This frequency (on average1–2 per decade) and duration (maximum 2 weeks) would have to beconsidered in planning commercial seaweed farming in St. Helena Bay.