Turning a corner on HIV neutralization?

HIV vaccine development has been hampered by the inability of conventional immunogens to elicit antibodies capable of neutralizing primary isolates of the virus. Recent studies using 'fusion-competent' immunogens that capture transitional intermediate structures of the functioning envelope protein suggest that this goal may now be achievable.     

Direct Interference on Competition in a Chemostat

Thispaperstudiestheglobaldynamicsofcompetitioninchemostatinwhichtwopopulationsofmicrooganismscompeteexploitativelyforasingle,essential,nonreproducing,growth-limitingsubstrateandthereisadirectinterferencebetweencompetitors.Inordertounderstandthedifferencesintheeffectsofintraspecificandinterspecificinterference,thebothcasesareconsideredrespectively.Keywords:##4Populationdynamicsecology;;chemostat;;competition;;interference;;interspecific;;intraspecific;;principalofcompetitiveexclusion     

α-d-Galactosidase immobilized on a soluble polymer

α-d-Galactosidase (α-d-galactoside galactohydrolase, EC 3.2.1.22) from green coffee beans has been immobilized by attachment to cyanogen bromide-activated Dextran T-70. Since this represents the first reported example of the preparation of a water-soluble derivative of an enzyme showing substrate inhibition, the kinetic properties, thermal stability and pH optima were investigated and compared with those of the free enzyme. The K_m, K_s, K_i, V_max, optimum substrate concentration and optimum pH were all lower than those of free enzyme. The enzyme conjugate showed greater resistance than the free enzyme to thermal inactivation. These data, although obtained with the synthetic substrate 4-nitrophenyl-α-d-galactoside, suggest some advantages in using the enzyme conjugate for the removal of terminal α-d-galactopyranosyl groups from the erythrocyte cell surface.     

When does a clone deserve a name? A perspective on bacterial species based on population genetics.

Molecular population-genetic analysis has revealed that for several human diseases, including tuberculosis, plague and shigellosis, the generally accepted taxonomic status of the organisms involved does not fit the usually accepted genus or species criteria. This raises the question of what species concept to apply to bacteria. We suggest that the species definition in bacteria should be based on analysis of sequence variation in housekeeping genes, and also that the "clone" be given official status in bacterial nomenclature. This will allow demotion of the species or genus status of several traditionally recognized human pathogens, but retention of current names of anomalous species and genera as clone names.     

Following a TRAIL： Update on a ligand and its five receptors

Identification of tumour necrosis factor apoptosis inducing ligand (TRAIL), a TNF family ligand, sparked a torrent of research, following an initial observation that it could kill tumour cells, but spare normal cells. Almost a decade after its discovery, and with five known receptors, the true physiological role of TRAIL is still debated and its anti-tumorigenic properties limited by potential toxicity. This review takes a comprehensive look at the story of this enigmatic ligand,addressing its remaining potential as a therapeutic and providing an overview of the TRAIL receptors themselves.     

Prey–predator mutualism in a tritrophic system on a camphor tree

We report the discovery of a mutualistic system encompassing prey–predator interactions. A domatium is a small space in a vein axil on the underside of leaves of woody angiosperms. Cinnamomum camphora Linn. has domatia that harbor a microphytophagous eriophyid mite (sp. 1). We previously reported that a predatory mite, Euseius sojaensis (Ehara), depends on this eriophyid mite as food. We revealed that E. sojaensis also preyed upon another eriophyid mite (sp. 2) that induces galls on leaves, and that the mean area of C. camphora leaves with galls was usually less than half that of leaves without galls. We experimentally tested the effect of E. sojaensis on galls, and confirmed that the presence of E. sojaensis reduced gall induction. Therefore, C. camphora, eriophyid mite sp. 1, and E. sojaensis comprise a mutualistic system, in spite of the prey–predator interactions among them. The conventional concept of mutualism does not apply to such prey–predator interactions, so we defined them as systematic mutualism. Here, the system consists of three trophic levels, and individuals that constitute this system benefit from the other species that constitute this system.     

Cancer research,a field on the verge of a paradigm shift?

The theoretical framework for the field of cancer research is based on two main principles. The first is that cancer advances in a stepwise manner, with each alteration driving cells further toward a malignant state. Second, to cure cancer we must target only cancer-specific properties. Here, we analyze the birth and propagation of the cancer research paradigm. We believe the current paradigm is immersed in crisis and that the field would benefit from integrating theories within and outside the normal modes of research to compile a new framework, with the hope of faster progress and significantly fewer cancer-related deaths.     

The aftermath of coral bleaching on a Maldivian reef—a quantitative study

Since the bleaching event of 1998, the development of the reef flat and upper reef slope on a Maldivian reef (the Komandoo house reef; Komandoo Island, Lhaviyani atoll or Fadiffolu atoll) is under detailed observation. We quantitatively recorded specific losses, re-colonisation by coral larvae on transects on the reef flat and on dead Acropora tables at the reef slope and regeneration of partly damaged large Porites and Diploastrea—colonies over the period from 1999 to 2004. The detrimental effects on the reef structure by bioerosion and hydrodynamics, as well as the overall status of the reef community were qualitatively assessed. Recruitment soon after the bleaching was more pronounced than in the following years, Pavona varians being a main constituent. The temporal re-colonisation pattern points at an emergency spawning of local Scleractinia just prior to the bleaching, whereas a sharp decrease of young settlers in 2001 and 2002 confirms a reduction of fertile colonies. The dominant species in the coral community shifted from acroporids and pocilloporids to agariciids. The skeletal deposition of recovering Diploastrea heliopora was equivalent to that before the bleaching, but much less than that of neighbouring Porites lobata colonies. The slow and scattered formation of new reef substance, which would structurally strengthen the reef, is however outweighed by the collapse of dead protruding and spacious colonies (e.g., Acropora tables). Six years after the bleaching, the formerly three-dimensional structure of the reef flat and upper reef slope presents as a levelled field of rubble, only partly consolidated by incrusting corals. Considering the recurrence of bleaching events (1987, 1998) and the results of the present study, one may assume a cascading deterioration of the status of the reef for the future.     

Immobilization and characterization of a thermostable β-galactosidase from a thermophilic anaerobe on a porous ceramic support

A thermostable -galactosidase (EC 3.2.1.23) from a thermophilic anaerobe, strain NA10, was purified from the crude extract of the Escherichia coli transformant harboring the lacN gene. The purified enzyme was physically and covalently immobilized to a porous ceramic support, SM-10. Among the supports tested, the highest residual activity after 3 h incubation at 70° C was obtained when the enzyme was covalently immobilized to silanized SM-10 with 3-[2-(2-amino-ethylaminoethylamino)propyl]trimethoxysilane. The amount of the enzyme immobilized was about 60 mg/g of this support. The enzymatic properties were almost the same as those of the free enzyme. The half-life of this immobilized enzyme was estimated to be approximately 450 h at the pasteurization temperature (65° C).On leave from Aichi Institute of Technology, Yakusa-cho, Toyota 470-03, Japan Correspondence to: T. Saito