Mutation analysis of PEX7 in 60 probands with rhizomelic chondrodysplasia punctata and functional correlations of genotype with phenotype

PEX7 encodes the cytosolic receptor for the set of peroxisomal matrix enzymes targeted to the organelle by the peroxisome targeting signal 2 (PTS2). Mutations in PEX7 cause rhizomelic chondrodysplasia punctata (RCDP), a distinct peroxisome biogenesis disorder. In previous work we described three novel PEX7 mutant alleles, including one, L292X, with a high frequency due to a founder effect. We have now extended our analysis to 60 RCDP probands and identified a total of 24 PEX7 alleles, accounting for 95% of the mutant PEX7 genes in our sample. Of these, 50% are L292X, 13% are IVS9+1G>C, and the remainder are mostly private. IVS9+1G>C occurs on at least three different haplotypes and thus appears to result from recurrent mutation. The phenotypic spectrum of RCDP is broader than commonly recognized and includes minimally affected individuals at the mild end of the spectrum. To relate PEX7 genotype and phenotype, we evaluated the consequence of the disease mutation on PEX7 RNA by Northern analysis and RT/PCR. We evaluated the function of the encoded Pex7 protein (Pex7p) by expressing selected alleles in fibroblasts from RCDP patients and assaying their ability to restore import of a PTS2 marker protein. We find that residual activity of mutant Pex7p and reduced amounts of normal Pex7p are associated with milder and variant phenotypes.     

In-depth study of bio-oil and biochar production from macroalgae Sargassum sp. via slow pyrolysis

Sargassum is undoubtedly one of the most predominant brown macroalgae, posing a significant disposal problem for coastal areas worldwide. The effective valorization of Sargassum sp. would be beneficial not only for environmental mitigation but also for producing high-value chemicals. However, the valorization of Sargassum sp. for bio-oil and biochar production via slow pyrolysis has not been well studied yet. Hence, this study aimed to conduct a comprehensive investigation into bio-oil and biochar production from Sargassum sp. via slow pyrolysis to provide valuable data for further valorization. A batch reactor was employed, and the pyrolysis of Sargassum sp. was conducted in a temperature range of 400–600 °C and with retention times of 10–50 min. The results showed significant compounds could be identified in bio-oil from Sargassum sp., including carboxylic acids, furan derivatives, aliphatic hydrocarbons, and N-aromatic compounds. Based on the ultimate analysis, the H/C and O/C atomic ratios of biochar were lower than the feedstock, reflecting the occurrence of dehydration and decarboxylation reactions throughout the pyrolysis. Biochar exhibited calorific values in the range of 23.12–25.89 MJ kg⁻¹, indicating it has more potential to be used as a solid fuel than low-ranked coals. Surface morphological analysis was performed by scanning electron microscopy (SEM) and showed a larger surface area in biochar than in the algal feedstock. Furthermore, a reaction model was deduced, and it was confirmed that the pyrolysis reaction obeyed the Arrhenius behaviour. Overall, the slow pyrolysis of Sargassum sp. provides an opportunity to obtain value-added chemicals and biochars, which could be further utilized for other applications.

Slow pyrolysis of brown macroalgae (Sargassum sp.) for bio-oil and biochar production.     

Hyperammonemia with reduced ornithine, citrulline, arginine and proline: a new inborn error caused by a mutation in the gene encoding delta(1)-pyrroline-5-carboxylate synthase

delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.     

At least two mutant alleles of ornithine delta-aminotransferase cause gyrate atrophy of the choroid and retina in Finns.

Gyrate atrophy of the choroid and retina (GA) is an inherited chorioretinal degeneration caused by deficiency of ornithine delta-aminotransferase (OAT; L-ornithine: 2-oxo-acid aminotransferase; EC 2.6.1.13). GA is one of the "Finnish genetic diseases," a group of several rare monogenic disorders that occur with increased frequency in the Finnish population. Using a combination of RNase A protection, genomic cloning, and polymerase chain reaction amplification of genomic DNA, we found one of two missense mutant OAT alleles to be present in each of 16 Finnish GA pedigrees. The first mutation R180T, in which arginine-180 is replaced by threonine, was present in homozygous form in patients from two pedigrees. The second mutation L402P, in which leucine-402 is replaced by proline, was present in homozygous form in patients from 14 pedigrees. Neither mutation was present in 19 Finnish controls. L402P was not present in 18 non-Finnish GA patients but R180T was found in an American GA patient. We constructed full-length mutant cDNAs by amplifying patient cDNA with the polymerase chain reaction and cloning a restriction fragment containing the mutation into an otherwise normal human OAT cDNA. These mutant cDNAs were then expressed in CHO-K1 cells, which lack endogenous OAT. Both R180T and L402P inactivate OAT. These results show molecular heterogeneity in GA alleles even in the Finnish population.     

Left subclavian artery revascularization in zone 2 thoracic endovascular aortic repair is associated with lower stroke risk across all aortic diseases

Background

The best management strategy for the left subclavian artery (LSA) in pathologic processes of the aorta requiring zone 2 thoracic endovascular aortic repair (TEVAR) remains controversial. We compared LSA coverage with or without revascularization as well as the different means of LSA revascularization.

Opioids induce convulsions and wet dog shakes in rats: mediation by hippocampal mu, but not delta or kappa opioid receptors

The opioid receptor subtypes and brain regions involved in eliciting convulsions and wet dog shakes (WDS) were studied by testing different opioid receptor selective agonists in unanesthetized rats. Selective mu agonists, [NMe-Phe3-D-Pro4]-morphiceptin (PL017) and [D-Ala2-N-methyl-Phe3-Gly5-ol]-enkephalin, induced convulsions and WDS when unilaterally injected into the ventral hippocampus. [D-Ala2,D-Leu5]-enkephalin (DADLE), a mixed mu and delta agonist, also elicited such behavioral changes, but its effect was less potent than the selective mu agonists. DADLE-induced WDS were dose dependent, and both convulsions and WDS were antagonized by the irreversible mu receptor antagonist, beta-funaltrexamine, but not by the selective delta receptor antagonist, ICI-174,864. Treatment with the selective delta agonist [D-Pen2,5]-enkephalin or the selective kappa agonists U-50,488H, dynorphin-A amide, or dynorphin-A(1-8) did not produce convulsions or WDS. The injection of a high dose of PL017 intraventricularly or into other brain regions such as the dorsal hippocampus, frontal cortex, striatum, and amygdala did not produce convulsions or WDS, therefore suggesting the ventral hippocampus is an important site for the expression of opioid-induced convulsions and WDS. These results suggest that opioid-induced convulsions and WDS are mediated exclusively by mu but not delta or kappa opioid receptors in the ventral hippocampus.     

Alcohol and open angle glaucoma--influence on detection, IOP, BP/IOP ratios

This study was undertaken to determine whether the ingestion of moderate amounts of ethyl alcohol should be contraindicated in the presence of open-angle glaucoma and/or might interfere with glaucoma detection by methods based on measurement of intraocular pressure (IOP) alone or of the ratios, systolic blood pressure and diastolic blood pressure to intraocular pressure, sBP/IOP and dBP/IOP, respectively. Following ingestion of alcohol at the rate of 1 ml/kg body weight, IOP, sBP, and dBP were measured in 73 adult subjects at 15 minute intervals for 90 minutes. Ingestation of alcohol resulted in a reduction of IOP, sBP, and dBP. The ratios sBP/IOP and dBP/IOP showed an increase. This included five subjects with a baseline sBP/IOP of less than 5.75. Results of this study suggest that ingestion of moderate amounts of alcohol will probably reduce IOP in open-angle glaucoma, and need not be contraindicated. On the other hand, consumption of a moderate quantity of alcohol by a subject one to two hours prior to participation in a gluacoma screening program may result in a missed detection by either of the usual criteria of IOP alone or of a BP/IOP ratio.     

Peritrophic membrane formation and the midgut barrier to arboviral infection in the mosquito, Culex tarsalis Coquillett (Insecta, Diptera).

The formation of the peritrophic membrane in adult female mosquitoes, Culex tarsalis, was examined by light and electron microscopy. The initial evidence of secretion of peritrophic membrane precursors occurred at 8-12 h after ingestion of the bloodmeal. Morphogenesis of the peritrophic membrane occurred within 12-16 h after the initial secretion; culminating with a fibrous, multilayered peritrophic membrane 20-24 h after bloodmeal ingestion. A discussion of the potential participation of the peritrophic membrane in a midgut barrier to infection by arboviruses is presented. The participation of the peritrophic membrane in a midgut barrier to infection of C. tarsalis, and many other mosquito species, by arboviruses is considered a moot point.