Modification by light of nitrite release and accumulation by Neurospora crassa

Activity of nitrate reductase (NR) induced by nitrate in the growth medium can be tested by diazotation of the nitrite formed during an activity test (Snell and Snell, 1949, Colorimetric Methods of Analysis, pp. 802-807). Pink instead of colorless controls (NADPH omitted) in these tests indicated nitrite present in the samples without NR activity and caused us to assay for nitrite excreted into the culture medium and for nitrite accumulated in the mycelia of Neurospora crassa strain al-2;bd

Effect of light on conidiation of nit and lis mutants of Neurospora crassa grown on different nitrogen sources

In addition to a recent paper (Ninnemann 1991. J. Photochem. Photobiol. 9:189-199), we are reporting further data on Neurospora crassa mutants supporting our hypothesis that the flavohemoenzyme nitrate reductase (NR) is involved in photoreception for light- promoted conidiation (Klemm and Ninnemann 1979. Photochem. Photobiol. 29:629-632). We looked for light-stimulated conidiation and NR activities in the NR- regulatory mutants nit-2 (FGSC 2698), nit-4 (2992) and nit-5 (985) from the Fungal Genetics Stock Center, University of Kansas, as well as the four NR+ mutants bd lis-1 (2891), bd lis-2 (2892), bd lis-3 (2983), and al-2 bd, received from Dr. S. Brody, University of California, San Diego. The three light insensitive lis mutants were isolated and described by Paietta and Sargent in 1983 (Genetics 104:11-21): the expression of their circadian rhythm was relatively insensitive to continuous light

Light-induced cyanide-insensitive respiration in wild type Neurospora crassa

Light-induced cyanide-insensitive respiration in wild type Neurospora crass

Detection of pterins and enzymatic activities of GTP-cyclohydrolase I and sepiapterin reductase in Neurospora crassa and Phycomyces blakesleeanus

The best known pterin in Neurospora crassa is molybdopterin, which is a constituent of the flavohemoenzyme nitrate reductase and participates in blue-light promoted conidiation (Klemm and Ninnemann 1979 Photochem

Rapid degradation of FAD following lysis of Neurospora crassa cells: Consequences for evaluation of flavin composition in vivo.

Rapid degradation of FAD following lysis of Neurospora crassa cells: Consequences for evaluation of flavin composition in vivo

Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand

The last interglacial (LIG; ~130 to ~118 thousand years ago, ka) was the last time global sea level rose well above the present level. Greenland Ice Sheet (GrIS) contributions were insufficient to explain the highstand, so that substantial Antarctic Ice Sheet (AIS) reduction is implied. However, the nature and drivers of GrIS and AIS reductions remain enigmatic, even though they may be critical for understanding future sea-level rise. Here we complement existing records with new data, and reveal that the LIG contained an AIS-derived highstand from ~129.5 to ~125 ka, a lowstand centred on 125–124 ka, and joint AIS + GrIS contributions from ~123.5 to ~118 ka. Moreover, a dual substructure within the first highstand suggests temporal variability in the AIS contributions. Implied rates of sea-level rise are high (up to several meters per century; m c−1), and lend credibility to high rates inferred by ice modelling under certain ice-shelf instability parameterisations.Universidade de VigoAustralian Research Council Laureate Fellowship | Ref. FL120100050RCN project THRESHOLDS | Ref. 2549

Clinical and cellular features in patients with primary autosomal recessive microcephaly and a novel CDK5RAP2 mutation

Background Primary autosomal recessive microcephaly (MCPH) is a rare neurodevelopmental disorder that results in severe microcephaly at birth with pronounced reduction in brain volume, particularly of the neocortex, simplified cortical gyration and intellectual disability. Homozygous mutations in the Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2 are the cause of MCPH3. Despite considerable interest in MCPH as a model disorder for brain development, the underlying pathomechanism has not been definitively established and only four pedigrees with three CDK5RAP2 mutations have been reported. Specifically for MCPH3, no detailed radiological or histological descriptions exist. Methods/Results We sought to characterize the clinical and radiological features and pathological cellular processes that contribute to the human MCPH3 phenotype. Haplotype analysis using microsatellite markers around the MCPH1-7 and PNKP loci in an Italian family with two sons with primary microcephaly, revealed possible linkage to the MCPH3 locus. Sequencing of the coding exons and exon/intron splice junctions of the CDK5RAP2 gene identified homozygosity for the novel nonsense mutation, c.4441C > T (p.Arg1481*), in both affected sons. cMRI showed microcephaly, simplified gyral pattern and hypogenesis of the corpus callosum. The cellular phenotype was assessed in EBV-transformed lymphocyte cell lines established from the two affected sons and compared with healthy male controls. CDK5RAP2 protein levels were below detection level in immortalized lymphocytes from the patients. Moreover, mitotic spindle defects and disrupted γ-tubulin localization to the centrosome were apparent. Conclusion These results suggest that spindle defects and a disruption of centrosome integrity play an important role in the development of microcephaly in MCPH3

Mutations in PTRH2 cause novel infantile-onset multisystem disease with intellectual disability, microcephaly, progressive ataxia, and muscle weakness

OBJECTIVE: To identify the cause of a so-far unreported phenotype of infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD). METHODS: We characterized a consanguineous family of Yazidian-Turkish descent with IMNEPD. The two affected children suffer from intellectual disability, postnatal microcephaly, growth retardation, progressive ataxia, distal muscle weakness, peripheral demyelinating sensorimotor neuropathy, sensorineural deafness, exocrine pancreas insufficiency, hypothyroidism, and show signs of liver fibrosis. We performed whole-exome sequencing followed by bioinformatic analysis and Sanger sequencing on affected and unaffected family members. The effect of mutations in the candidate gene was studied in wild-type and mutant mice and in patient and control fibroblasts. RESULTS: In a consanguineous family with two individuals with IMNEPD, we identified a homozygous frameshift mutation in the previously not disease-associated peptidyl-tRNA hydrolase 2 (PTRH2) gene. PTRH2 encodes a primarily mitochondrial protein involved in integrin-mediated cell survival and apoptosis signaling. We show that PTRH2 is highly expressed in the developing brain and is a key determinant in maintaining cell survival during human tissue development. Moreover, we link PTRH2 to the mTOR pathway and thus the control of cell size. The pathology suggested by the human phenotype and neuroimaging studies is supported by analysis of mutant mice and patient fibroblasts. INTERPRETATION: We report a novel disease phenotype, show that the genetic cause is a homozygous mutation in the PTRH2 gene, and demonstrate functional effects in mouse and human tissues. Mutations in PTRH2 should be considered in patients with undiagnosed multisystem neurologic, endocrine, and pancreatic disease

Selberg Supertrace Formula for Super Riemann Surfaces III: Bordered Super Riemann Surfaces

This paper is the third in a sequel to develop a super-analogue of the classical Selberg trace formula, the Selberg supertrace formula. It deals with bordered super Riemann surfaces. The theory of bordered super Riemann surfaces is outlined, and the corresponding Selberg supertrace formula is developed. The analytic properties of the Selberg super zeta-functions on bordered super Riemann surfaces are discussed, and super-determinants of Dirac-Laplace operators on bordered super Riemann surfaces are calculated in terms of Selberg super zeta-functions.Comment: 43 pages, amste