Association of casein kinase II with microtubules

A magnesium-dependent heparin-inhibited protein kinase activity associated with brain microtubule preparations has been identified as casein kinase II using a monospecific polyclonal antibody. This enzyme appears enriched in cold-stable microtubule fractions. By immunofluorescence microscopy using an antiserum against casein kinase II, the in situ immunolabeling of some microtubule assays has been observed. Thus, mitotic spindles are stained by the anti-casein kinase II antibody in fibroblast cells. In neuroblastoma cells induced to differentiate, the labeling of microtubule arrays inside developing axon-like processes is also seen. These results support the view that casein kinase II can modulate cytoskeletal assembly and dynamics through phosphorylation of microtubule proteins.     

Centromere pattern in different mouse seminiferous tubule cells

Centromere arrangement in different mouse seminiferous tubule cells was analyzed using an anticentromere antiserum from a patient with the CREST syndrome of scleroderma. A peptide of 18 kd was recognized by this serum on immunoblotting of mouse nuclear proteins from seminiferous tubule cells. In the cells studied by immunofluorescence, different patterns of centromere arrangement were observed. A speckled arrangement of centromeres was found in spermatogonia, double spots corresponding to meiotic bivalents were found in pachytene cells, and clusters of a haploid numer of centromeres were found in early and acrosome phase spermatids. In Sertoli cells, only three centromeric spots were detected, corresponding to the nucleolar organizer chromosome pairs. A relationship between the functional stage of the cell and the arrangement of and conformational changes in the centromeres is considered.     

Phosphorylation of alpha-tubulin carboxyl-terminal tyrosine prevents its incorporation into microtubules

Insulin receptor kinase phosphorylated tubulin in an insulin-dependent fashion. Two different populations of phosphotubulin were found. In tubulin dimers containing tyrosine at the carboxyl-terminal of their alpha subunit, phosphate was incorporated in that residue, and the phosphorylated protein did not assemble into polymers. In tubulin dimers lacking this tyrosine residue, phosphate was incorporated into different tyrosine residues located in other parts of the molecule, and the phosphoprotein retained its capacity to polymerize.     

Breast and Bottle Feeding as Risk Factors for Dental Caries: A Systematic Review and Meta-Analysis

Understanding the role that breastfeeding and bottle feeding play in the development of dental caries during childhood is essential in helping dentists and parents and care providers prevent the disease, and also for the development of effective public health policies. However, the issue is not yet fully understood. The aim of this systematic review and meta-analysis was to search for scientific evidence in response to the question: Do bottle fed children have more dental caries in primary dentition than breastfed children? Seven electronic databases and grey literature were used in the search. The protocol number of the study is PROSPERO CRD 42014006534. Two independent reviewers selected the studies, extracted data and evaluated risk of bias by quality assessment. A random effect model was used for meta-analysis, and the summary effect measure were calculated by odds ratio (OR) and 95% CI. Seven studies were included: five cross-sectional, one case-control and one cohort study. A meta-analysis of cross-sectional studies showed that breastfed children were less affected by dental caries than bottle fed children (OR: 0.43; 95%CI: 0.23–0.80). Four studies showed that bottle fed children had more dental caries (p<0.05), while three studies found no such association (p>0.05). The scientific evidence therefore indicated that breastfeeding can protect against dental caries in early childhood. The benefits of breastfeeding until age two is recommended by WHO/UNICEF guidelines. Further prospective observational cohort studies are needed to strengthen the evidence.     

Toward a general mixed quantum/classical method for the calculation of the vibronic ECD of a flexible dye molecule with different stable conformers: Revisiting the case of 2,2,2‐trifluoro‐anthrylethanol

We extend a recently proposed mixed quantum/classical method for computing the vibronic electronic circular dichroism (ECD) spectrum of molecules with different conformers, to cases where more than one hindered rotation is present. The method generalizes the standard procedure, based on the simple Boltzmann average of the vibronic spectra of the stable conformers, and includes the contribution of structures that sample all the accessible conformational space. It is applied to the simulation of the ECD spectrum of (S)‐2,2,2‐trifluoroanthrylethanol, a molecule with easily interconvertible conformers, whose spectrum exhibits a pattern of alternating positive and negative vibronic peaks. Results are in very good agreement with experiment and show that spectra averaged over all the sampled conformational space can deviate significantly from the simple average of the contributions of the stable conformers. The present mixed quantum/classical method is able to capture the effect of the nonlinear dependence of the rotatory strength on the molecular structure and of the anharmonic couplings among the modes responsible for molecular flexibility. Despite its computational cost, the procedure is still affordable and promises to be useful in all cases where the ECD shape arises from a subtle balance between vibronic effects and conformational variety.     

Do benthic and planktonic diatoms produce equivalent effects in crustaceans?

Hippolyte inermis Leach 1814 is a benthic shrimp characterized by a peculiar mechanism of sex reversal influenced by diatom foods. In fact, the appearance of primary females in spring is due to an apoptotic early disruption of the androgenic gland and of the male gonad, triggered by still unknown compounds present in diatoms of the genus Cocconeis. The influence of diatoms on the reproductive ecology and life cycle of planktonic crustaceans has been demonstrated previously: some planktonic diatoms produce aldehydes inducing apoptosis in the embryos and in the larvae of marine copepods, reducing their viability. Both benthic and planktonic diatoms therefore produce compounds having an apoptotic effect on some tissues of target crustaceans, although the ecological significance of the two processes is different: deleterious for copepod populations, regulative for shrimps associated with Posidonia oceanica. In the present article we experimentally administered specific planktonic diatoms, their fractions and compounds known to induce apoptosis in planktonic copepods, to H. inermis postlarvae, to check whether the apoptotic effect is due to an identical family of diatom compounds, and to establish whether the processes observed in the plankton and in the benthos, respectively, are analogous or homologous, from an ecological point of view. Our results indicated that diatom compounds acting in the two systems are different, since both planktonic diatoms and their aldehydes had negligible effects on the sex ratios of cultured shrimps.