Boron in Relation to Membrane Function in Higher Plants

The capacity for absorption of phosphate was shown to be reducedin Zea mays and Vicia faba suffering from boron deficiency;addition of 10^–5 M boron rapidly restored this capacity.Root tips of normal plants also responded to the addition ofboron during a short pretreatment period prior to the determinationof phosphate absorption. Comparable effects of boron on theabsorption of chloride and rubidium ions were also demonstratedin Zea mays. Specific inhibition of ion uptake by auxins maybe relevant to the mechanism of the impaired ion transport seenduring boron deficiency. The KCl-stimulated adenosine triphosphatase (ATPase) of theroots of Zea mays was also studied, with a view to examiningthe effect of boron deficiency on the activity of the enzyme.Boron-deficient roots had a reduced ATPase activity which couldbe rapidly restored by the addition of 10^–4 M H₃BO₃ 1h before extraction of the enzyme. The results suggest that the activity of specific membrane componentscan be directly influenced by boron. Possible mechanisms wherebythis control is exercised include direct interaction of boronwith polyhydroxy components of the membrane and the elevationof endogenous levels of auxins. The evidence presented stronglysupports the view that boron plays an essential role in theregulation of the functions of higher plant membranes and thatthe ATPase is a possible component of the transplant process.     

PREDATOR-PREY INTERACTIONS BETWEEN LEPSIELLA (BEDEVA) PAIVAE (GASTROPODA: MURICIDAE) AND KATELYSIA SCALARINA (BIVALVIA: VENERIDAE) IN PRINCESS ROYAL HARBOUR, WESTERN AUSTRALIA

On a sandy beach at Shoal Bay in Princess Royal Harbour, Albany,southwestern Western Australia, lives a small muricid gastropodthat feeds virtually monotonically on the overwhelmingly dominantresident bivalve Katelysia scalarina. Lepsiella paivae livesburied in the sand and attacks its prey within it. Because ofits small size (<13 mm shell height), bivalve prey isalso small and this study demonstrates a preference for K. scalarinaof 5 mm shell length, i.e. juveniles. Laboratory experimentsalso suggested a possible preference for attack of the rightvalve. Lepsiella paivae can and does, however, attack largerprey (up to 15 mm shell length), but cannot consume themcompletely. A second visit to Princess Royal Harbour in theAustral winter, when there was no juvenile K. scalarina present,showed L. paivae to be attacking at the sand surface, also bydrilling, the small (<4 mm) gastropod Hydrococcus brazieri(Hydrococcidae). SEM studies of experimentally determined drillholes of L. paivae show them to be of variable form, some straightsided, others bevelled (like a naticid) and <500 µmin diameter. On this sheltered Southern Ocean beach, therefore,L. paivae has specialized to attack juvenile bivalves by burrowingafter them. It can, however, attack other species opportunisticallyon the sand surface when seasonally favoured juvenile bivalveprey are not present. (Received 8 January 2005; accepted 16 March 2005)     

PROTASPIDES OF UPPER CAMBRIAN APHELASPIS (PTYCHOPARIIDA, TRILOBITA) AND RELATED SPECIES WITH THEIR TAXONOMIC IMPLICATIONS

Abstract:  The ontogeny of Aphelaspis brachyphasis is illustrated and described on the basis of newly discovered silicified material from the McGill section, Nevada, USA. Protaspides of three other Aphelaspis species are redescribed. Of ptychopariide species for which protaspides have been documented, the protaspides of those previously considered to be closely related to Aphelaspis are illustrated herein. Protaspides of Aphelaspis are most similar to those of Olenus , supporting previous taxonomic suggestions that the Aphelaspidinae is closely related to the Olenidae and may be assigned to the Olenacea. The protaspides of Housia share few similarities with those of Aphelaspis , contradicting the hypothesis that these genera are placed together within the Pterocephaliidae.     

Deficit schizophrenia: an update

The criteria for deficit schizophrenia were designed to define a group of patients with enduring, primary (or idiopathic) negative symptoms. In 2001, a review of the literature suggested that deficit schizophrenia constitutes a disease separate from nondeficit forms of schizophrenia. Here we provide a review of new studies, not included in that paper, in which patients with deficit schizophrenia and those with nondeficit schizophrenia were compared on dimensions typically used to distinguish diseases: signs and symptoms, course of illness, pathophysiological correlates, risk and etiological factors, and treatment response. Replicated findings and new evidence of double dissociation supporting the separate disease hypothesis are highlighted. Weaknesses in research and treatment options for these patients are also emphasized.     

Habitat-associated morphological divergence in two Neotropical fish species

We examined intraspecific morphological diversification between river channel and lagoon habitats for two Neotropical fish ( Bryconops caudomaculatus , Characidae; Biotodoma wavrini , Cichlidae). We hypothesized that differences between habitats (e.g. flow regime, foraging opportunities) might create selective pressures resulting in morphological divergence between conspecific populations. We collected fish from four channel-lagoon habitat pairs in the Río Cinaruco, Venezuela, and compared body morphology using geometric morphometrics. There were two aspects of divergence in both species: (1) placement of maximum body depth and (2) orientation of the mouth. For both species, maximum body depth was positioned more anteriorly (i.e. fusiform) in the river channel than in lagoons. Both species exhibited a relatively terminal mouth in lagoons compared to the channel. The mouth of B. caudomaculatus was relatively upturned, whereas the mouth of B. wavrini was relatively subterminal, in channel habitats. Observed morphological patterns are consistent with functional morphological principles suggesting adaptive divergence. We also show that spatial distance between habitats, presumably reflecting rates of population mixing, appears to have constrained diversification. For both species, morphological divergence increased with distance between habitats. Thus morphological divergence between channel and lagoon habitats apparently reflects a balance between diversification driven by natural selection, and homogenization driven by population mixing.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 689–698.     

The Piltdown forgery: a re-statement of the case against Hinton

A review of the evidence supports the conclusion reached by Gardiner and Currant in 1996 that the hoaxer was Martin Hinton, who worked in the Geology and Zoology Departments of the Natural History Museum throughout the Piltdown affair. This was based primarily on the discovery in 1978 of a cabin trunk in the loft space immediately above what had been the office of the Keeper of Zoology − which post Hinton occupied between 1936 and 1945. This contained material similarly stained to that discovered at Piltdown, while several of the pieces had also been whittled in an identical fashion to the last find at Piltdown – the notorious 'cricket bat'. Additional proof came from Hinton's executor who discovered eight human teeth varyingly stained in a tobacco tin of Hinton's. These revealed that the forger used two methods for staining his material, one of which involved decalcification, a process which converted apatite into gypsum, the other of which did not. The material in the trunk was stained using the first method, the teeth obtained from his executor, the second. The analyses of the contents of the trunk (carried out in 1995−6) and of the tobacco tin (1997−8) are reported for the first time.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society, 2003, 139 , 315−335.     

The impact of pH on interactions among phytoplankton algae, zooplankton and perch (Perca fluviatilis) in a shallow, fertile lake

1. The combined effects of increasing pH (< 9–11) and increasing densities of perch (0, two, four per enclosure) have been investigated in polyethylene enclosures of volume about 1100 1 in a shallow, fertile lake in Cheshire. 2. Increasing pH decreased carbon dioxide concentrations, chlorophyll a concentrations and diatom biomass. It led to increases in the proportions of Cryptophyta (to pH 10) and Chlorophyta (to pH 11). Although ample inocula were present, significant growths of cyanophytes were not recorded, contrary to expectation. 3. Increasing pH led to increases in numbers of Daphnia hyalina particularly at pH 10 but collapse at pH 11. This persistence at pH 10, independent of perch number, is attributed to reduced feeding of the fish, which survived at this pH. Other zooplankters (Ceriodaphnia spp., Bosmina longirostris, Polyphemus pediculus, Cyclops spp.) all declined with increasing pH. 4. Increasing fish density resulted in an increase in chlorophyll a concentration and in the biomass of Chlorophyta but had no effect on cyanophyte or cryptophyte biomass. 5. Increasing fish density led to declines in Daphnia in the untreated lake-water controls (pH < 9) and at pH 9, but had no effect at pH 10 where Daphnia hyalina was very abundant. Numbers of Ceriodaphnia spp. and Bosmina longirostris increased with increasing fish density, whilst numbers of Polyphemus pediculus and Cyclops spp. were independent of it. 6. The results are discussed in the light of contemporary knowledge of the factors resulting in large cyanophyte growths and of the factors controlling the stability of macrophyte-dominated and phytoplankton-dominated states in shallow lakes. The interaction between pH and fish density and consequent non-linear response of Daphnia hyalina is particularly notable because of the significance of zooplankton grazing in shallow lakes.