Differences between antigenic determinants of pig and cat zona pellucida proteins

Despite many efforts, the control of reproduction in feral cat populations is still a problem in urban regions around the world. Immunocontraception is a promising approach; thus the present study examined the suitability of the widely used pig zona pellucida proteins (pZP) for contraception in feral domestic cats. Purified zona pellucida proteins obtained from pig and cat ovaries were used to produce highly specific antisera in rabbits. Antibodies against pZP raised in rabbits or lions were not effective inhibitors of either in vitro sperm binding (cat spermatozoa to cat oocytes) or in vitro fertilization in cats, whereas antibodies against feline zona pellucida proteins (fZP) raised in rabbits showed a dose-dependent inhibition of in vitro fertilization. Immunoelectrophoresis, ELISA and immunohistology of ovaries confirmed these results, showing crossreactivity of anti-fZP sera to fZP and to a lesser extent to pZP, but no interaction of anti-pZP sera with fZP. It is concluded that cat and pig zonae pellucidae express a very small number of shared antigenic determinants, making the use of pZP vaccine in cats questionable. A contraceptive vaccine based on feline zona pellucida determinants will be a better choice for the control of reproduction in feral cats if immunogenity can be achieved.     

Identification of Sox8 as a modifier gene in a mouse model of Hirschsprung disease reveals underlying molecular defect

Mice carrying heterozygous mutations in the Sox10 gene display aganglionosis of the colon and represent a model for human Hirschsprung disease. Here, we show that the closely related Sox8 functions as a modifier gene for Sox10-dependent enteric nervous system defects as it increases both penetrance and severity of the defect in Sox10 heterozygous mice despite having no detectable influence on enteric nervous system development on its own. Sox8 exhibits an expression pattern very similar to Sox10 with occurrence in vagal and enteric neural crest cells and later confinement to enteric glia. Loss of Sox8 alleles in Sox10 heterozygous mice impaired colonization of the gut by enteric neural crest cells already at early times. Whereas proliferation, apoptosis, and neuronal differentiation were normal for enteric neural crest cells in the gut of mutant mice, apoptosis was dramatically increased in vagal neural crest cells outside the gut. The defects in enteric nervous system development of mice with Sox10 and Sox8 mutations are therefore likely caused by a reduction of the pool of undifferentiated vagal neural crest cells. Our study suggests that Sox8 and Sox10 are jointly required for the maintenance of these vagal neural crest stem cells.     

Isoprenoid biosynthesis in chloroplasts via the methylerythritol phosphate pathway: the (E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (GcpE) from Arabidopsis thaliana is a [4Fe–4S] protein

The mevalonate-independent methylerythritol phosphate pathway is widespread in bacteria. It is also present in the chloroplasts of all phototrophic organisms. Whereas the first steps, are rather well known, GcpE and LytB, the enzymes catalyzing the last two steps have been much less investigated. 2-C-Methyl-D-erythritol 2,4-cyclodiphosphate is transformed by GcpE into 4-hydroxy-3-methylbut-2-enyl diphosphate, which is converted by LytB into isopentenyl diphosphate or dimethylallyl diphosphate. Only the bacterial GcpE and LytB enzymes have been investigated to some extent, but nothing is known about the corresponding plant enzymes. In this contribution, the prosthetic group of GcpE from the plant Arabidopsis thaliana and the bacterium Escherichia coli has been fully characterized by Mössbauer spectroscopy after reconstitution with ⁵⁷FeCl₃, Na₂S and dithiothreitol. It corresponds to a [4Fe-4S] cluster, suggesting that both plant and bacterial enzymes catalyze the reduction of 2-C-methyl-D-erythritol 2,4-cyclodiphosphate into (E)-4-hydroxy-3-methylbut-2-enyl diphosphate via two consecutive one-electron transfers. In contrast to the bacterial enzyme, which utilizes NADPH/flavodoxin/flavodoxin reductase as a reducing shuttle system, the plant enzyme could not use this reduction system. Enzymatic activity was only detected in the presence of the 5-deazaflavin semiquinone radical.     

Comparison of three liquid lures for trapping social wasps (Hymenoptera: Vespidae)

Two citrus-based sodas and a known wasp attractant were compared in a field trial to assess their attractiveness to local nuisance wasp species. The wasps captured included Vespula germanica (F.), Vespula maculifrons (Buysson), Vespula vulgaris (L.), Vespula flavopilosa Jacobson, Vespula squamosa (Drury), Dolichovespula maculata (L.), Polistes fuscatus (L.), Polistes metricus Say, and Polistes dominulus (Christ). Wasps in the genus Vespula were present in significantly higher numbers in traps than Dolichovespula and Polistes. Both citrus soda products were superior to the isobutanol-acetic acid mixture as attractants for almost all of the wasp species.     

Sox10-rtTA mouse line for tetracycline-inducible expression of transgenes in neural crest cells and oligodendrocytes

Using gene targeting, we inserted a high-affinity variant of the reverse tetracycline controlled transactivator (rtTA) into the genomic Sox10 locus. This rtTA transgene faithfully recapitulated Sox10 expression in the emerging neural crest, several of its derivatives, and in oligodendrocytes. It was furthermore able to induce expression of a tetracycline inducible transgenic reporter gene in a doxycycline-dependent manner. Induction was fast, with substantial reporter gene expression visible 6 h after the onset of doxycycline treatment. Shut-off, in contrast, exhibited delayed kinetics, which probably correlated with doxycycline clearance rates. This mouse provides a useful tool for generating tetracycline-controlled gene expression in neural crest and oligodendrocytes.     

CombAlign: a protein sequence comparison algorithm considering recombinations

The basic linear treatment of sequence comparisons limits the ability of contemporary sequence alignment algorithms to detect non-order-conserving recombinations. Here, we introduce the algorithm combAlign which addresses the assessment of pairwise sequence similarity on non-order-conserving recombinations on a large scale. Emphasizing a two-level approach, combAlign first detects locally well conserved subsequences in a target and a source sequence. Subsequently, the relative placement of alignments is mapped to a graph. Concatenating local alignments to reassemble the target sequence to the fullest extent, the maximum scoring path through the graph denotes the best attainable combAlignment. Parameters influencing this process can be set to meet the user's specific demands. combAlign is applied to examples demonstrating the possibility to reflect evolutionary kinship of proteins even if their domains and motifs are strongly rearranged.     

Changes in the association of low birth weight with socioeconomic status in Hawaii: 1970-1990

This study examines rates of low birth weight (LBW) in the state of Hawaii and changes in the association of LBW with socioeconomic status from 1970 to 1990. The analysis is based on aggregate data for census tracts. Rates of low birth weight were calculated for each census tract. Relative socioeconomic scores were calculated from average household income and years of education. The results show that (1) there was a decrease in the rate of low birth weight infants in Hawaii; and (2) that the correlation between socioeconomic status and low birth weight was substantially reduced, though a significant correlation remains. The paper suggests likely ceiling effects, but that the progressive public health policies and expansion of access to primary health care in Hawaii during this period played a major role in reducing the rate of low birth weight infants and in decreasing socioeconomic inequality on this important health indicator.     

Interaction of tropomyosin-troponin with actin filaments

The assembly of actin filaments with tropomyosin-troponin was investigated by means of light scattering. Binding curves of tropomyosin-troponin [consisting of all three subunits (holotroponin)] and of tropomyosin-troponin-T-I to actin filaments were analyzed by separating the affinity of tropomyosin-troponin for actin filaments and the affinity for the end-to-end contact of tropomyosin molecules. Under the experimental conditions (42.4 degrees C, 300 mM KCl), tropomyosin-holotroponin in the absence of calcium and tropomyosin-troponin-T-I had similar affinities for actin filaments whereas tropomyosin-holotroponin in the presence of calcium was found to bind more weakly. Tropomyosin-holotroponin and tropomyosin-troponin-T-I bound about 200-300-fold more strongly to binding sites with adjacent tropomyosin-troponin units than to isolated sites on actin filaments. The equilibrium constant for isolated association with actin filaments was more than 2-fold higher for tropomyosin-holotroponin in the absence of calcium (15 400 M-1) and tropomyosin-troponin-T-I (17 500 M-1) than for tropomyosin-holotroponin in the presence of calcium (6600 M-1). Binding curves of mixtures of tropomyosin-holotroponin in the presence of calcium and of tropomyosin-troponin-T-I were measured and analyzed on the basis of a model of cooperative binding of two types of large ligands to a one-dimensional homogeneous lattice. The results provided information on the strength of the end-to-end contacts of tropomyosin-troponin units in different positions on an actin filament. It was found that a tropomyosin-troponin unit binds adjacently to another unit in a different position on an actin filament about 2-fold more weakly than adjacent to a unit in the same position. With the aid of these results, it was possible to obtain information of the equilibrium distribution of tropomyosin-troponin in the two positions on actin filaments. Generation of a sequence of tropomyosin-troponin units in a different position on actin filaments was found to be 4-fold less favored than elongation of an existing sequence (cooperativity parameter sigma = 1/4). Shifting of tropomyosin-troponin on actin filaments appears to be accompanied by small free-energy changes in the various interactions of the components of actin-tropomyosin-troponin filaments and not to be an all-or-none reaction