G-6-PD polymorphism and racial admixture in the Cuban population

Summary Esterase D phenotypes were determined in 1082 non-related individuals from the western region of Germany by agarose-gel electrophoresis. Gene frequencies were compared with previous data and all European populations studied so far agreed with the Hardy-Weinberg equilibrium. Mean gene frequencies for Europeans are: EsD ¹ 0.8888, EsD ² 0.1112.     

Predicting potentially pathogenic effects of hRPE65 missense mutations: a computational strategy based on molecular dynamics simulations

The human retinal pigment epithelium-specific 65-kDa protein (hRPE65) plays a crucial role within the retinoid visual cycle and several mutations affecting either its expression level or its enzymatic function are associated with inherited retinal diseases such as Retinitis Pigmentosa. The gene therapy product voretigene neparvovec (Luxturna) has been recently approved for treating hereditary retinal dystrophies; however, the treatment is currently accessible only to patients presenting confirmed biallelic mutations that severely impair hRPE65 function, and many reported hRPE65 missense mutations lack sufficient evidences for proving their pathogenicity. In this context, we developed a computational approach aimed at evaluating the potential pathogenic effect of hRPE65 missense variants located on the dimerisation domain of the protein. The protocol evaluates how mutations may affect folding and conformation stability of this protein region, potentially helping clinicians to evaluate the eligibility for gene therapy of patients diagnosed with this type of hRPE65 variant of uncertain significance.     

A 3D doubly sensitivity enhanced X-filtered TOCSY-TOCSY experiment

We present a 3D double sensitivity enhanced X-filtered homonuclear TOCSY-TOCSY experiment for the assignment of unlabeled molecules complexed to labeled protein- or nucleic acid-domains. The resulting spectrum is clean, can be measured in a reasonable amount of time and allows for increased resolution of overlapping resonances when compared to 2D methods. The 3D X-filtered TOCSY-TOCSY allows for assignment in cases where the size or the composition of the unlabeled molecule results in a high degree of overlap.     

Signs of stabilisation and stable coexistence

Many empirical studies motivated by an interest in stable coexistence have quantified negative density dependence, negative frequency dependence, or negative plant–soil feedback, but the links between these empirical results and ecological theory are not straightforward. Here, we relate these analyses to theoretical conditions for stabilisation and stable coexistence in classical competition models. By stabilisation, we mean an excess of intraspecific competition relative to interspecific competition that inherently slows or even prevents competitive exclusion. We show that most, though not all, tests demonstrating negative density dependence, negative frequency dependence, and negative plant–soil feedback constitute sufficient conditions for stabilisation of two‐species interactions if applied to data for per capita population growth rates of pairs of species, but none are necessary or sufficient conditions for stable coexistence of two species. Potential inferences are even more limited when communities involve more than two species, and when performance is measured at a single life stage or vital rate. We then discuss two approaches that enable stronger tests for stable coexistence‐invasibility experiments and model parameterisation. The model parameterisation approach can be applied to typical density‐dependence, frequency‐dependence, and plant–soil feedback data sets, and generally enables better links with mechanisms and greater insights, as demonstrated by recent studies.     

Natural acidification changes the timing and rate of succession,alters community structure,and increases homogeneity in marine biofouling communities

Ocean acidification may have far‐reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO₂ at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate‐scale pCO₂ change and, if high pCO₂ is relieved mid‐succession, whether past acidification effects persist, are reversed by alleviation of pCO₂ stress, or are worsened by departures from prior high pCO₂ conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments along a shallow water volcanic pCO₂ gradient to assess the importance of the timing and duration of high pCO₂ exposure (i.e., discrete events at different stages of successional development vs. continuous exposure) on patterns of colonization and succession in a benthic fouling community. We show that succession at the acidified site was initially delayed (less community change by 8 weeks) but then caught up over the next 4 weeks. These changes in succession led to homogenization of communities maintained in or transplanted to acidified conditions, and altered community structure in ways that reflected both short‐ and longer‐term acidification history. These community shifts are likely a result of interspecific variability in response to increased pCO₂ and changes in species interactions. High pCO₂ altered biofilm development, allowing serpulids to do best at the acidified site by the end of the experiment, although early (pretransplant) negative effects of pCO₂ on recruitment of these worms were still detectable. The ascidians Diplosoma sp. and Botryllus sp. settled later and were more tolerant to acidification. Overall, transient and persistent acidification‐driven changes in the biofouling community, via both past and more recent exposure, could have important implications for ecosystem function and food web dynamics.     

The α-<Emphasis Type="SmallCaps">l</Emphasis>-fucosidase from <Emphasis Type="Italic">Sulfolobus solfataricus</Emphasis>

Glycoside hydrolases form hyperthermophilic archaea are interesting model systems for the study of catalysis at high temperatures and, at the moment, their detailed enzymological characterization is the only approach to define their role in vivo. Family 29 of glycoside hydrolases classification groups α-l-fucosidases involved in a variety of biological events in Bacteria and Eukarya. In Archaea the first α-l-fucosidase was identified in Sulfolobus solfataricus as interrupted gene expressed by programmed −1 frameshifting. In this review, we describe the identification of the catalytic residues of the archaeal enzyme, by means of the chemical rescue strategy. The intrinsic stability of the hyperthermophilic enzyme allowed the use of this method, which resulted of general applicability for β and α glycoside hydrolases. In addition, the presence in the active site of the archaeal enzyme of a triad of catalytic residues is a rather uncommon feature among the glycoside hydrolases and suggested that in family 29 slightly different catalytic machineries coexist.