Disentangling functional trait variation and covariation in epiphytic lichens along a continent-wide latitudinal gradient

Characterizing functional trait variation and covariation, and its drivers, is critical to understand the response of species to changing environmental conditions. Evolutionary and environmental factors determine how traits vary among and within species at multiple scales. However, disentangling their relative contribution is challenging and a comprehensive trait-environment framework addressing such questions is missing in lichens. We investigated the variation in nine traits related to photosynthetic performance, water use and nutrient acquisition applying phylogenetic comparative analyses in lichen epiphytic communities on beech across Europe. These poikilohydric organisms offer a valuable model owing to their inherent limitations to buffer contrasting environmental conditions. Photobiont type and growth form captured differences in certain physiological traits whose variation was largely determined by evolutionary processes (i.e. phylogenetic history), although the intraspecific component was non-negligible. Seasonal temperature fluctuations also had an impact on trait variation, while nitrogen content depended on photobiont type rather than nitrogen deposition. The inconsistency of trait covariation among and within species prevented establishing major resource use strategies in lichens. However, we did identify a general pattern related to the water-use strategy. Thus, to robustly unveil lichen responses under different climatic scenarios, it is necessary to incorporate both among and within-species trait variation and covariation.

Niemann-Pick disease type A and B are clinically but also enzymatically heterogeneous: pitfall in the laboratory diagnosis of sphingomyelinase deficiency associated with the mutation Q292 K

This study describes a diagnostic pitfall in the laboratory diagnosis of patients with sphingomyelinase deficiency (SMD; Niemann-Pick disease types A and B; NPA and NPB), in cases where sphingomyelinase activity was not determined with sphingomyelin as the natural enzymic substrate. Four of 24 SMD patients studied had falsely normal or enhanced activity, when a so-called artificial sphingomyelinase substrate, 2-N-(hexadecanoyl)-amino-4-nitrophenyl phosphorylcholine (HNP), was used, whereas SMD was clear with the sphingomyelin substrate. Those four patients had the Q292 K mutation of the acid sphingomyelinase gene (SMPD1) on at least one allele. Three of the four patients (no data available from one) experienced only late-infantile or juvenile, though distinct, neurological involvement, where learning disabilities, hypo- or areflexia or mild ataxia were initial signs. The laboratory pitfall with HNP substrate, which is used in many laboratories, raises the risk that some SMD patients are overlooked, and it prevents the consideration of a late-manifesting neurological course in some patients as well as the planning of enzyme substitution therapy in non-neurological SMD (NPB) patients. Since classical NPB is very rare, it is suggested that SMD patients with late- or mild-manifesting neurological symptoms should better be assigned to additional SMD subgroups than grouped with NPB.

Malformations of the midline commissures: MRI findings in different forms of callosal dysgenesis

Malformations of the corpus callosum (CC) may occur in many different syndromes. Various forms have been observed. We report seven cases of malformation of the CC. Special attention is directed towards the development of the fornix and hippocampus as a hippocampal commissure is a prerequisite of normal hippocampal development. The clinical disability of the patients presented here differed significantly, which may in part be due to the different extent of this cerebral malformation. The relevance of the concomitant aplasia of the limbic system has not been addressed in detail previously in the literature.

Unusual chromosomal mosaicism as a cause of mental retardation and congenital malformations in a familial reciprocal translocation carrier, t(17;22)(q24.2;q11.23)

Familial reciprocal translocations are generally without phenotypic effect, although there is some evidence for a small excess of mental retardation and congenital malformations (MR/CM) in children carrying familial reciprocal translocations. Possible mechanisms whereby such translocations could have a phenotypic effect include cryptic unbalanced rearrangements, uniparental disomy, and disruption of putative genes at the breakpoints, unmasking recessive alleles on the normal homologs. Mosaicism for a supernumerary derivative chromosome in a carrier of a familial reciprocal translocation has not yet been described. We report a boy presenting with MR/CM and a familial reciprocal translocation, t(17;22)(q24.2;q11.23), inherited from the mother. Cytogenetic analysis of peripheral blood lymphocytes showed a balanced karyotype in all 32 analyzed metaphase spreads. Molecular genetic analysis was consistent with biparental origin of the normal homologs. In metaphase spreads from skin fibroblasts a supernumerary chromosome was found in all 24 cells analyzed and could be identified as der(22)t(17;22)(q24.2;q11.23). Several possible segregation modes at meiosis I followed by meiosis II or postzygotic nondisjunction of the der(22) might have led to this unusual chromosomal mosaicism. We propose hidden mosaicism as a possible cause for MR/CM in patients who apparently carry a balanced familial reciprocal translocation.

Saxicolous species of the genus Rinodina (lichenized Ascomycetes, Physciaceae) in southern Africa. ACTA ACUST UNITED AC 1996. [DOI: 10.4102/abc.v26i1.683]

A revision of saxicolous species of the genus Rinodina (Ach.) Gray (lichenized Ascomycetes. Phvsciaceae) in southern Africa is presented. The study area covers the following countries: Angola. Namibia. Republic of South Africa. Lesotho.Swaziland, Zimbabwe, and Mozambique. Fifteen Rinodina species are treated in detail, and three of them are new to science:Rinodina longisperma Matzer H.Mayrhofer.  R. scabridula Matzer H.Mayrhofer, and  R. striatitunicata Matzer H.Mayrhofer. The general part of the study includes information on the most important characters of the species with a special focus on ascospore types and ontogeny, and biogeographical notes are also given. A key to the species is provided. All the species are described in detail with notes on their ascus characters, spermogonial apparatus, and chemical characteristics, and their substrate and general distribution are indicated. The descriptions are accompanied by illustrations of the ascospores. Except for Rinodina oxydata s.I., the distribution of all the species in southern Africa and other parts of Africa respectively, is mapped.Several names were referred into synonymy, including Rinodina almbornii H.Mayrhofer. a synonym of R. confragosula (Nyl. in Cromb.) Miill.Arg.. and R. depressa (Vain.) Zahlbr. and R. albicans H.Mayrhofer which are synonymous to R. huillensis Vain.A separate section encompasses nine excluded species.