Entrapment of active ion-permeable cyanobacteria (Anacystis nidulans) in calcium alginate

Summary Cells of the unicellular cyanobacterium Anacystis nidulans were made permeable to ions by treating them with lysozyme and EDTA in a way that leaves the photosynthetic water-splitting function, the photoreduction of exogenous oxidants and the peptidoglycan exoskeleton of the cell virtually intact. The permeabilized cells (permeaplasts) were subsequently immobilized by entrapment in calcium alginate beads. The immobilized preparation exhibits remarkable stability both on storage and in action. On prolonged storage at room temperature in darkness, its photosynthetic activity deteriorates one-third as fast as the activity of immobilized intact cells. Illumination accelerates deactivation. Tested in prolonged runs, however, performed in an illuminated open reactor, alginate-immobilized Anacystis permeaplasts were capable of photoreducing ionic oxidants (ferricyanide) and of exporting ionic reductants (ferrocyanide) to the suspension medium continuously for more than 5 h before being totally inactivated. It is also shown that the major impediment to the photoreduction performance of immobilized permeaplasts arises from diffusion limitations, while the photonic limitation due to light reflection and scattering is approx. 7%.Abbreviations Chl chlorophyll - CSTR continuously stirred tank reactor - EDTA ethylenediaminetetraacetate - FeCN potassium ferricyanide - pBQ p-benzoquinone - PD p-phenylenediamine - PD_ox p-phenylenediamine in the presence of excess potassium ferricyanide - Hepes N-2-hydroxyethylpiperazine-N-2 ethane-sulphonic acid     

The unusually strong stabilizing effects of glycine betaine on the structure and function of the oxygen-evolving Photosystem II complex

Natural osmoregulatory substances (osmolytes) allow a wide variety of organisms to adjust to environments with high salt and/or low water content. In addition to their role in osmoregulation, some osmolytes protect proteins from denaturation and deactivation by, for example, elevated temperature and chaotropic compounds. A ubiquitous protein-stabilizing osmolyte is glycine betaine (N-trimethyl glycine). Its presence has been reported in bacteria, in particular cyanobacteria, in animals and in plants from higher plants to algae. In the present review we describe the experimental evidence related to the ability of glycine betaine to enhance and stabilize the oxygen-evolving activity of the Photosystem II protein complexes of higher plants and cyanobacteria. The osmolyte protects the Photosystem II complex against dissociation of the regulatory extrinsic proteins (the 18 kD, 23 kD and 33 kD proteins of higher plants and the 9 kD protein of cyanobacteria) from the intrinsic components of the Photosystem II complex, and it also stabilizes the coordination of the Mn cluster to the protein cleft. By contrast, glycine betaine has no stabilizing effect on partial photosynthetic processes that do not involve the oxygen-evolving site of the Photosystem II complex. It is suggested that glycine betaine might act, in part, as a solute that is excluded from charged surface domains of proteins and also as a contact solute at hydrophobic surface domains.     

Literature Review and Comparison of Two Statistical Methods to Evaluate the Effect of Botulinum Toxin Treatment on Gait in Children with Cerebral Palsy

Aim

This study aimed at comparing two statistical approaches to analyze the effect of Botulinum Toxin A (BTX-A) treatment on gait in children with a diagnosis of spastic cerebral palsy (CP), based on three-dimensional gait analysis (3DGA) data. Through a literature review, the available expert knowledge on gait changes after BTX-A treatment in children with CP is summarized.

Methods

Part 1—Intervention studies on BTX-A treatment in children with CP between 4–18 years that used 3DGA data as an outcome measure and were written in English, were identified through a broad systematic literature search. Reported kinematic and kinetic gait features were extracted from the identified studies. Part 2—A retrospective sample of 53 children with CP (6.1 ± 2.3years, GMFCS I-III) received 3DGA before and after multilevel BTX-A injections. The effect of BTX-A on gait was interpreted by comparing the results of paired samples t-tests on the kinematic gait features that were identified from literature to the results of statistical parametric mapping analysis on the kinematic waveforms of the lower limb joints.

Results

Part 1–53 kinematic and 33 kinetic features were described in literature. Overall, there is no consensus on which features should be evaluated after BTX-A treatment as 49 features were reported only once or twice. Part 2—Post-BTX-A, both statistical approaches found increased ankle dorsiflexion throughout the gait cycle. Statistical parametric mapping analyses additionally found increased knee extension during terminal stance. In turn, feature analyses found increased outtoeing during stance after BTX-A.

Conclusion

This study confirms that BTX-A injections are a valuable treatment option to improve gait function in children with CP. However, different statistical approaches may lead to different interpretations of treatment outcome. We suggest that a clear, definite hypothesis should be stated a priori and a commensurate statistical approach should accompany this hypothesis.     

Monoclonal gammopathy in chronic myeloproliferative disorders

The incidence of monoclonal gammopathy in 61 patients with chronic myeloproliferative disorders (CMPD) was studied. The distribution of patients among the CMPD subgroups was: chronic myelocytic leukemia, 24 patients; myelofibrosis, 11; polycythemia vera, 15; essential thrombocythemia, 7; unclassified MPD, 4 patients. Monoclonal gammopathy was found in 5 patients (8.2%). Two of these patients (1 IgA/k and 1 IgM/k) had myelofibrosis and 3 (2 IgG/k and 1 IgG/lambda) polycythemia vera. The presence of monoclonal gammopathy indicates an involvement of the lymphoplasmatic system in CMPD.     

Intrauterine administration of prostaglandin by the extra-amniotic route

The present study was undertaken to explore whether abortion in the 13th-16th week of gestation could be induced by a single extra-amniotic injection of prostaglandin. A long acting prostaglandin analogue 15(S)-15-Methyl-PGF2alpha was utilized and different vehicles and injection techniques tried. The clinical results of the single injection method were compared with those using multiple injections of PGF2alpha as has been described earlier. It was found that approximately 80% of the patients aborted following a single injection of 750 mc 15-me-PGF2alpha and that the side effect rate was acceptable from a clinical point of view. The method seems to be an attractive alternative usable during the "difficult" period for induction of abortion, i.e., when the uterus is too large for vacuum aspiration but too small for abdominal puncture of the amniotic sac.     

Administration of 15-methyl-prostaglandin F2α as a pre-operative means of cervical dilatation

Pre-operative dilatation of the cervix prior to vacuum aspiration was accomplished in 67 volunteers by extra-amniotic or intra-muscular administration of 15(S)-15-methyl-PGF_2α (15-me-PGF_2α). Ninety-four per cent of the patients were in the 11th–13th week of gestation and 61% were nulliparae. A single extra-amniotic instillation (mean of 400 μg) or 3 intramuscular injections (300–800 μg per injection) of the compound induced a satisfactory outcome in terms of either abortion or sufficient dilatation of the cervix in 81% of the patients. In the remaining cases, the cervix was found at operation to be open for 7–9 mm which simplified the process of additional instrumental dilatation. In general the outcome of the trial turned the operation into an easy and safe procedure. Vacuum aspiration was performed in all cases after a mean time lag of 16 hours following the onset of the treatment. Extra-amniotic administration was associated with a low incidence of gastro-intestinal side-effects, but there was a transient and moderate degree of uterine pain reaction. The intramuscular route was technically more simple and caused less uterine pain but the high incidence of vomiting and diarrhoea constituted a clinical disadvantage. In late first trimester abortions, particularly cases where the uterus appears larger than expected, it is believed that dilatation of the cervix by PG prior to vacuum aspiration is a sound clinical indication. The method offers definite advantages that compensate for the price of some minor side-effects.     

A morphogen gradient model for pattern regulation. I. Formation of non-repetitive and repetitive structures

A model for pattern formation is proposed based on two concentration gradients S and Sigma. S is a local morphogen generated by a reaction-diffusion mechanism while Sigma is a by-product of the S-decomposition. Under certain conditions S is well approximated by S(x,L) = alpha(L)f(x L ), where alpha(L) is a scaling function of the length L and f(x L ) is a monotonie function of the relative distance x L from the origin. Sigma degradates and diffuses in the field, reaching a stable L-dependent homogeneous distribution. An allosteric protein P with several active sites reacts with S and Sigma and separates the field into segments. To every segment a corresponding active state of P is dominant. Pattern regulation is automatically achieved since the compartmerttal separation depends explicitly only on x L . For the case of repetitive patterns, a supplementary Gierer-Meinhardt mechanism is introduced for activator X and inhibitor Y. The level of Sigma can affect the decomposition rate of X or Y, e.g. via a second order degradation reaction, hence making the chemical wavelength lambda size-dependent. For a particular decay scheme of Y, a variation of L induces a change of lambda so that finally the number of repetitive structures becomes independent of the field size.     

Optimal synthesis of chromatographic trains for downstream protein processing

Downstream bioprocessing and especially chromatographic steps, commonly used for the purification of multicomponent systems, are significant cost drivers in the production of therapeutic proteins. There has been an increased interest in the development of systematic methods for the design of such processes, and the appropriate selection of a series of chromatographic steps is still a major challenge to be addressed. Several models have been developed previously but have assumed that 100% recovery of the desired product is obtained at each chromatographic step. In this work, a mathematical framework is proposed, based on mixed integer optimisation techniques, that removes this assumption and allows full flexibility on the position of retention time cut-points, between which the desired product fraction is collected. The proposed model is demonstrated on three example protein mixtures, each containing up to 13 contaminants and selecting from a set of up to 21 candidate steps. The proposed model results in a reduction of one to three chromatographic steps over solutions that no losses are allowed.     

Dark-to-light transition in <Emphasis Type="Italic">Synechococcus</Emphasis> sp. PCC 7942 cells studied by fluorescence kinetics assesses plastoquinone redox poise in the dark and photosystem II fluorescence component and dynamics during state 2 to state 1 transition

We investigated the dark-to-light transition in Synechococcus sp. PCC 7942 cells by a detailed analysis of fluorescence transients induced by strong red light. The transients, recorded with high data-acquisition, revealed all the steps of the fast (OJIP; 10⁻⁵–1 s) and slow phase (PSM(T); 1–10³ s), kinetically distinguished with precision. Focusing on the OJIP-rise, we show, for the first time, how the variable to initial fluorescence ratio and the relative height of J-level can serve as indexes of the plastoquinone redox poise and the established state in the dark; hence, differences among cyanobacteria can be recognised in a simple way. Applying intermittent illumination (20-s light pulses separated by 10-s dark intervals) to induce dark-to-light transition and analysing the individual transients, we establish a method by which we determine the fluorescence component not originating from photosystem (PS) II and we assess PSII dynamics during state 2 to state 1 transition. The development of photochemical and non-photochemical quenching is also discussed, as well as evidences favouring the mobile antenna model.     

A patient with partial trisomy 21 and 7q deletion expresses mild Down syndrome phenotype

Backround

Down syndrome (DS) is the most common aneuploidy in live-born individuals and it is well recognized with various phenotypic expressions. Although an extra chromosome 21 is the genetic cause for DS, specific phenotypic features may result from the duplication of smaller regions of the chromosome and more studies need to define genotypic and phenotypic correlations.

Case report

We report on a 26 year old male with partial trisomy 21 presenting mild clinical symptoms relative to DS including borderline intellectual disability. In particular, the face and the presence of hypotonia and keratoconus were suggestive for the DS although the condition remained unnoticed until his adult age array comparative genomic hybridization (aCGH) revealed a 10.1 Mb duplication in 21q22.13q22.3 and a small deletion of 2.2 Mb on chromosomal band 7q36 arising from a paternal translocation t(7;21). The 21q duplication encompasses the gene DYRK1.

Conclusion

Our data support the evidence of specific regions on distal 21q whose duplication results in phenotypes recalling the typical DS face. Although the duplication region contains DYRK1, which has previously been implicated in the causation of DS, our patient has a borderline IQ confirming that their duplication is not sufficient to cause the full DS phenotype.