Distribution of PACAP (pituitary adenylate cyclase-activating polypeptide)-like and helospectin-like peptides in the teleost gut

Pituitary adenylate cyclase-activating polypeptide (PACAP) and helospectin are two vasoactive intestinal polypeptide (VIP)-related neuropeptides that have recently been demonstrated in the mammalian gut; the aim of this study was to reveal their occurrence and localisation in the gastrointestinal tract, swimbladder, urinary bladder and the vagal innervation of the gut of teleosts, using immunohistochemical methods on whole-mounts and sections of these tissues from the Atlantic cod, Gadus morhua and the rainbow trout, Oncorhynchus mykiss. Both PACAP-like and helospectin-like peptides were present in the gut wall of the two species. Immunoreactive nerve fibres were found in all layers but were most frequent in the myenteric plexus and along the circular muscle fibres. Immunoreactivity was also demonstrated in nerves innervating the swimbladder wall, the urinary bladder and blood vessels to the gut. Immunoreactive nerve cell bodies were found in the myenteric plexus of the gut and in the muscularis mucosae of the swimbladder. In the vagus nerve, non-immunoreactive nerve cells were surrounded by PACAP-immunoreactive fibres. Double staining revealed the coexistence of PACAP-like and helospectin-like peptides with VIP in all visualized nerve fibres and in some endocrine cells. It is concluded that PACAP-like and helospectin-like peptides coexist with VIP in nerves innervating the gut of two teleost species. The distribution suggests that both PACAP and helospectin, like VIP, are involved in the control of gut motility and secretion.     

The use of constitutive nuclear oncoproteins to count neurons in the enteric nervous system of the guinea pig

Immunohistochemical double labelling of the enteric nervous system of the guinea pig ileum was performed with a monoclonal antibody (anti-MYC 033) directed against a peptide sequence of the human c-Myc protein together with antibodies directed against either the neuron-specific antigens neuron-specific enolase or PGP 9.5 or the glia-specific marker S-100 to demonstrate that anti-MYC 033 labelled the nuclei of all enteric neurons but not glia. This strategy was also employed to demonstrate that another anti-c-Myc monoclonal anti-body, anti-MYC 070, labelled the nuclei of all neurons and glia, as well as perhaps all other cells in these preparations. A polyclonal antiserum raised against a peptide sequence of the human c-Fos protein (anti-FOS 4) was shown to label the identical nuclei as anti-MYC 033. The ganglionic density of nuclei labelled by anti-FOS 4 was found to be similar to previous measures of the ganglionic density of neurons. Double labelling with anti-MYC 033 and an antiserum directed against vasoactive intestinal polypeptide was performed to reexamine the ganglionic density of neurons that express this neuropeptide. Our results suggest that the ganglionic density of these neurons might be less than previously determined.     

The legumin gene family: a reconstructed Vicia faba legumin gene encoding a high-molecular-weight subunit is related to type B genes

Nucleotide sequence information from a partial genomic clone, a cDNA clone, a RACE clone and a PCR fragment was combined to reconstruct the first reported complete gene sequence encoding a large legumin subunit, designated LelB3. The length difference to the well-characterized major legumin subunits is caused by an extended glutamin/glutamic acid-rich region encoded by the C-terminal part of the chain. Amino acid sequence comparisons reveal that gene LelB3 is more closely related to B-type than to A-type legumin genes of Vicia faba. Gene LelB3 is a member of a small gene family as indicated by published (Pich and Schubert, Biol Zbl 112 (1993); 342–350) and limited own data.     

Constitutive and inducible aspects of nitrate-nitrogen uptake by Chlamydomonas reinhardtii

Similarly to higher plant root systems, Chlamydomonas reinhardtii Dangeard (UTEX 90) cells exhibited biphasic NO₃^? uptake kinetics. The uptake pattern was similar in cells cultured in 10 mM NO₃^? (NO₃^?-grown), 0.25 mM NO₃^? (N-limited) or 10 mM NO₃^? followed by an 18-h period of N-deprivation (N-starved). In all cell types there was an apparent phase transition in uptake at 1.1 mM NO₃^?, although there were variations in the uptake V_max of both isotherms. The rate of uptake via isotherm 0 ([NO₃^?]<1.1 mM) in N-limited cells was higher than that of either NO₃^?-grown or N-starved cells. In contrast, NO₃^?-grown and N-limited cells exhibited comparable V_max values when supplied with 1.1 to 1.8 mM NO₃^? (isotherm 1). When supplied with 1.6 mM NO₃^?, both N-limited and N-starved cells exhibited enhanced linear uptake after 60 min of incubation. We ascribed this to an induction phenomenon. This trend was not observed when NO₃^?-grown cells were supplied with 1.6 mM NO₃^?, or when N-limited and N-starved cells were supplied with 0.6 mM NO₃^?. The ‘inducible’ aspect of uptake by N-limited cells was blocked by cycloheximide (10 mg l^?1), but not by actinomycin D (5 mg l^?1), thus indicating the involvement of a translational or post-translational event. To investigate this phenomenon further, we analysed the cell proteins of N-limited cells supplied with either 0.6 or 1.6 mM NO₃^? for 90 min, using two-dimensional gel electrophoresis. Comparison of protein profiles enabled the identification of a single cell membrane-associated polypeptide (21 kDa, pI ca 5.5) and ten soluble fraction polypeptides (17–73 kDa, pI ca 5.0 to 7.1) unique to the high NO₃^? treatment. We propose that the ‘inducible’ portion of NO₃^? uptake may provide the means by which C. reinhardtii cells regulate uptake in accordance with assimilatory capacity.     

Selective extraction of 22 kDa and 10 kDa polypeptides from Photosystem II without removal of 23 kDa and 17 kDa extrinsic proteins

Selective solubilization of Photosystem II membranes with the non-ionic detergent octyl thioglucopyranoside has allowed the isolation of a PS II system which has been depleted of the 22 and 10 kDa polypeptides but retains all three extrinsic proteins (33, 23 and 17 kDa). The PS II membranes which have been depleted of the 22 and 10 kDa species show high rates of oxygen evolution activity, external calcium is not required for activity and the manganese complex is not destroyed by exogenous reductants. When we compared this system to control PS II membranes, we observed a minor modification of the reducing side, and a conversion of the high-potential to the low-potential form of cytochrome b ₅₅₉.Abbreviations Chl- chlorophyll - DCBQ- 2,5-dichloro-p-benzoquinone - DCMU- 3-(3,4-dichlorophenyl)-1,1-dimethylurea - ESR- electron spin resonance - MES- 2-(N-morpholino)ethanesulfonic acid - OTG- octyl--d-thioglucopyranoside - PS II- Photosystem II - PEG- polyethylene glycol, M_r=6000 - Tris- 2-amino-2-hydroxyethylpropane-1,3-diol     

灰茶尺蛾核型多角体病毒某些生化特性的研究

灰茶尺蛾核型多角体病毒某些生化特性的研究李彦章,石正丽,陈棣华（中国科学院武汉病毒研究所,武汉４３００７１）关键词灰茶尺蛾,核型多角体病毒,结构多肽,限制性内切酶图谱灰茶尺蛾核型多角体病毒（Ｅｃｔｒｏｐｉｓｇｒｉｓｅｓｃｅｎｓｎｕｃｌｅａｒｐｏｌｙｈ...     

Short-term effects of a large dam decommissioning on biofilm structure and functioning

Aging dams and the rising efforts to restore stream ecosystems are increasing the number of dam decommissioning programs. Although dam decommissioning aims at improving in-stream habitat, biodiversity, and ecosystem functioning in the long term, it might also cause ecological impacts in the short term due to the mobilization of the sediment accumulated in the reservoir. Benthic biofilm in particular can be impaired by episodes of high turbidity and scouring. We conducted a multiple before-after/control-impact experiment to assess the effects of the drawdown of a large dam (42 m tall), a first step to its decommissioning, on biofilm structure (biomass and chlorophyll-a) and functioning (metabolism, nutrient uptake, and organic matter breakdown). Our results show that the reservoir drawdown reduced the autotrophic biofilm biomass (chlorophyll-a) downstream from the dam, which in turn lowered metabolism. However, nitrogen and phosphorus uptake by the biofilm was not affected. Organic matter breakdown was slower below the dam than in nearby undammed reaches before and during drawdown. All drawdown effects quickly disappeared and reaches downstream from the dam approached values found in nearby undammed reaches. Thus, our results indicate that the effects of reservoir drawdown on stream biofilms exist but may be small and disappear rapidly.     

TTLL11 gene is associated with sustained attention performance and brain networks: A genome-wide association study of a healthy Chinese sample

Genetic studies on attention have mainly focused on children with attention-deficit/hyperactivity disorder (ADHD), so little systematic research has been conducted on genetic correlates of attention performance and their potential brain mechanisms among healthy individuals. The current study included a genome-wide association study (GWAS, N = 1145 healthy young adults) aimed to identify genes associated with sustained attention and an imaging genetics study (an independent sample of 483 healthy young adults) to examine any identified genes' influences on brain function. The GWAS found that TTLL11 showed genome-wide significant associations with sustained attention, with rs13298112 as the most significant SNP and the GG homozygotes showing more impulsive but also more focused responses than the A allele carriers. A retrospective examination of previously published ADHD GWAS results confirmed an un-reported, small but statistically significant effect of TTLL11 on ADHD. The imaging genetics study replicated this association and showed that the TTLL11 gene was associated with resting state activity and connectivity of the somatomoter network, and can be predicted by dorsal attention network connectivity. Specifically, the GG homozygotes showed lower brain activity, weaker brain network connectivity, and non-significant brain-attention association compared to the A allele carriers. Expression database showed that expression of this gene is enriched in the brain and that the G allele is associated with lower expression level than the A allele. These results suggest that TTLL11 may play a major role in healthy individuals' attention performance and may also contribute to the etiology of ADHD.