X-ray structure and spectroscopic properties of pentasodium bis(l-tartrato(4-)-O,O,O) manganate(III) dodecahydrate

X-ray crystallographic analysis of Na₅[Mn(l-tart)₂] · 12H₂O demonstrated that Mn(III) ion has two tridentate l-tartrates of which two deprotonated hydroxo groups and one carboxylate are coordinated in contrast to the previously proposed structure with two didentate tartrates and two coordinated water. The tetragonally distorted octahedron due to the Jahn-Teller effect was discussed in relation with the large splitting components for the UV-Vis and circular dichroism (CD) spectra in the d-d transition in the solid. The significant difference in the UV-Vis and CD spectra between the solid and the solution suggests that the tridentate coordination of the tartrate in the solid complex changes to the didentate one in the solution.     

Low-rank scale-invariant tensor product smooths for generalized additive mixed models

A general method for constructing low-rank tensor product smooths for use as components of generalized additive models or generalized additive mixed models is presented. A penalized regression approach is adopted in which tensor product smooths of several variables are constructed from smooths of each variable separately, these "marginal" smooths being represented using a low-rank basis with an associated quadratic wiggliness penalty. The smooths offer several advantages: (i) they have one wiggliness penalty per covariate and are hence invariant to linear rescaling of covariates, making them useful when there is no "natural" way to scale covariates relative to each other; (ii) they have a useful tuneable range of smoothness, unlike single-penalty tensor product smooths that are scale invariant; (iii) the relatively low rank of the smooths means that they are computationally efficient; (iv) the penalties on the smooths are easily interpretable in terms of function shape; (v) the smooths can be generated completely automatically from any marginal smoothing bases and associated quadratic penalties, giving the modeler considerable flexibility to choose the basis penalty combination most appropriate to each modeling task; and (vi) the smooths can easily be written as components of a standard linear or generalized linear mixed model, allowing them to be used as components of the rich family of such models implemented in standard software, and to take advantage of the efficient and stable computational methods that have been developed for such models. A small simulation study shows that the methods can compare favorably with recently developed smoothing spline ANOVA methods.     

Multinuclear magnetic resonance, electrospray ionization-mass spectroscopy, and parametric method 5 studies of a new derivative of gossypol with 2-thiophenecarbohydrazide as well as its complexes with LI+, Na+, K+, RB+, and Cs+ cations

A new derivative of racemic gossypol with 2-thiophenecarbohydrazide (GHHT) and its complexes with monovalent cations have been synthesized and studied by electrospray ionization-mass spectroscopy (ESI-MS), multinuclear nuclear magnetic resonance (NMR), as well as by the Parametric Method 5 (PM5) methods. It is demonstrated that GHHT forms stable complexes of 1:1 stoichiometry with monovalent metal cations. The structures of the complexes are stabilized by three types of intramolecular hydrogen bonds. The spectroscopic methods have provided clear evidence that GHHT and its complexes exist in the DMSO-d6 solution in the N-imine-N-imine tautomeric forms. The structures of the GHHT and its complexes with Li+, Na+, K+, Rb+, and Cs+ cations are visualized and discussed in detail.     

Deleterious Pleiotropic Effects of the Atypical Aldehyde Dehydrogenase 2 (ALDH2) Allele: Comment on Luo et al., 2005

Luo [Biochem. Genet. 43:223–227] concluded, “The mutation ALDH2⁽ 487Lys allele is not deleterious but is of great benefit to human health.” This statement is easily subject to misinterpretation and needs to be clarified. Their results actually show there is a pleiotropic effect associated with the mutation ALDH2⁽ 487Lys allele that is as deleterious as the risk of alcoholism for which it offers protection, and thus there is no net benefit from having the mutation. A clarification is needed because this statement and others in the paper might be used inappropriately as an endorsement of practices that are in fact worthless, because it masks the need to find what the pleiotropic effect is, and because it seems to contradict what otherwise seems to be a general rule of evolution.     

Role of the membrane interface on the conformation of the caveolin scaffolding domain: a CD and NMR study

Circular dichroism (CD) and NMR spectroscopy were used to study the conformational properties of two synthetic peptides, D82-R101 and D82-I109, encompassing the caveolin scaffolding domain (D82-R101), in the presence of dodecylphosphocholine (DPC) micelles. Our data show that a stable helical conformation of the caveolin scaffolding domain in a membrane mimicking system is only obtained for the peptide including the L102-I109 hydrophobic stretch, a part of the caveolin intra-membrane domain. Through chemical shift variations, an ensemble of six residues of the D82-L109 peptide, mainly located in the V(94)TKYWFYR(101) motif were found to detect the presence of phosphatidylserine solubilized in DPC micelles. Our results constitute a first step for elucidating at a residue level the conformational properties of the central region of the caveolin-1 protein.     

NMR investigation of DNA primer-template models: structural insights into dislocation mutagenesis in DNA replication

Slipped frameshift intermediates can occur when DNA polymerase slows or stalls at sites of DNA lesions. However, this phenomenon is much less common when unmodified DNA is replicated. In order to study the effect of templating bases on the alignment of primer-templates, NMR structural investigation has been performed on primer-template oligonucleotide models which mimic the situation that dNTP has just been incorporated opposite template. NMR evidence reveals the occurrence of misalignment when dGTP is incorporated opposite template T with a downstream nucleotide C. Depending on the template sequence, further extension of the primer can lead to realignment.     

Spatial and temporal dynamics of oviposition behavior of bollworm and three of its predators in Bt and non-Bt cotton fields

Host plants exhibiting insect resistance traits have long been known to influence within‐plant distributions of pests and their natural enemies. Sites and timing of egg deposition are particularly important for synchrony of predators and their prey in the field. Temporal and spatial distribution of eggs of the cotton bollworms [Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae)] and that of the predators Geocoris punctipes (Say) (Heteroptera: Geocoridae), Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae), and Micromus spec. (Neuroptera: Hemerobiidae) were determined during three cotton seasons, from 2002 to 2004, by collecting and examining plants throughout each season. Comparisons also were made between Bt and non‐Bt cotton to investigate possible changes in oviposition behavior on Bt cotton. The study was conducted in commercial fields with insecticide use to manage pests when economic thresholds were exceeded in both cotton types. Egg densities for predators and bollworms varied among years, but were similar on Bt and non‐Bt cottons. Oviposition of bollworms and G. punctipes correlated spatially within plants, with most eggs laid on structures in the top five nodes of cotton plants and on the three outermost leaves on lateral branches regardless of cotton type. Bollworm oviposition dynamics exhibited two peaks within the season (early July and early August). Eggs of all predators and bollworms collected from the field and incubated in the laboratory had high hatching rates throughout each season (74–100%). Temporal association of predator with bollworm oviposition showed a significant correlation with green lacewings, a delay of 10 days for big‐eyed bugs, and no correlation with brown lacewings. Furthermore, Bt cotton plants exerted no significant effect on temporal or spatial patterns of oviposition of bollworms or the predators, indicating no change in oviposition behavior of bollworm females within plant structures after almost one decade of widespread planting of Bt cotton.     

Population demography and the evolution of helping behaviors

Limited dispersal may favor the evolution of helping behaviors between relatives as it increases their relatedness, and it may inhibit such evolution as it increases local competition between these relatives. Here, we explore one way out of this dilemma: if the helping behavior allows groups to expand in size, then the kin-competition pressure opposing its evolution can be greatly reduced. We explore the effects of two kinds of stochasticity allowing for such deme expansion. First, we study the evolution of helping under environmental stochasticity that may induce complete patch extinction. Helping evolves if it results in a decrease in the probability of extinction or if it enhances the rate of patch recolonization through propagules formed by fission of nonextinct groups. This mode of dispersal is indeed commonly found in social species. Second, we consider the evolution of helping in the presence of demographic stochasticity. When fecundity is below its value maximizing deme size (undersaturation), helping evolves, but under stringent conditions unless positive density dependence (Allee effect) interferes with demographic stochasticity. When fecundity is above its value maximizing deme size (oversaturation), helping may also evolve, but only if it reduces negative density-dependent competition.     

Solution structure and dynamics of human metallothionein-3 (MT-3)

Alzheimer's disease is characterized by progressive loss of neurons accompanied by the formation of intraneural neurofibrillary tangles and extracellular amyloid plaques. Human neuronal growth inhibitory factor, classified as metallothionein-3 (MT-3), was found to be related to the neurotrophic activity promoting cortical neuron survival and dendrite outgrowth in the cell culture studies. We have determined the solution structure of the alpha-domain of human MT-3 (residues 32-68) by multinuclear and multidimensional NMR spectroscopy in combination with the molecular dynamic simulated annealing approach. The human MT-3 shows two metal-thiolate clusters, one in the N-terminus (beta-domain) and one in the C-terminus (alpha-domain). The overall fold of the alpha-domain is similar to that of mouse MT-3. However, human MT-3 has a longer loop in the acidic hexapeptide insertion than that of mouse MT-3. Surprisingly, the backbone dynamics of the protein revealed that the beta-domain exhibits similar internal motion to the alpha-domain, although the N-terminal residues are more flexible. Our results may provide useful information for understanding the structure-function relationship of human MT-3.