Pyridine Nucleotides in Plant Mitochondria. Amounts, metabolism and contribution to electron transport

HPLC analysis was used for direct quantification of amounts and redox levels of pyridine nucleotides in plant mitochondria. The amount of NAD(H) and NADP+ varied, 1.0-3.7 and 0-0.5 nmol (mg protein)-1, respectively, depending on the species from which nucleotides were extracted. NADPH was never detected. Submitochondrial localisation of NAD+-degrading enzymes indicated that matrix NAD+ diffuses intact across the inner mitochondrial membrane and is metabolised by NAD+-catabolising enzymes in the outer membrane. NAD pyrophosphatase activity was identified as being involved in the pyridine nucleotide degradation. During malate oxidation by isolated Solanum tuberosum mitochondria, the highest levels of NAD(H) reduction were obtained when malic enzyme was active. The lowest NAD(H) reduction levels were seen when conditions favoured malate dehydrogenase activity. Rotenone increased the reduction level of intramitochondrial NADH. Diphenylene iodonium (DPI) inhibited malate oxidation in the presence of rotenone in isolated mitochondria. This result indicated participation of matrix NADPH and the internal rotenone-insensitive, DPI-sensitive, NADPH dehydrogenase during malate oxidation. Antisera raised against peptides deduced from two S. tuberosum genes (nda1 and ndb1), homologous to the yeast genes for the internal and external NADH:ubiquinone dehydrogenases specifically cross-reacted with 48 and 61 kDa polypeptides in potato tuber mitochondria, respectively. Native NDA1 and NDB1 occurred as higher molecular mass forms, and show different association to the inner mitochondrial membrane. The physiological significance of pyridine nucleotide turnover and occurrence of multiple NAD(P)H dehydrogenases in the inner mitochondrial membrane is discussed

A survey of the nitrate and phosphate levels of inshore marine waters from Malta (Central Mediterranean)

The nitrate and phosphate levels were monitored over a one-year period in three inshore localities in Malta. There were recorded no seasonal variations in nutrient levels at Marsaxlokk bay. At Mistra bay a slight decrease in nitrate-nitrogen was recorded during the autumn and winter periods. At both these locations, how- ever the nitrate-nitrogen was generally below llJig-atil and phosphate-phosphorus al- ways less than 0.2 /J1.g-atll. The values are typical of most areas in the Mediterranean. The concentrations of nutrients at Rinella creek were consistently manifold higher and peaked during the winter months. This, very probably, reflects the combined effects of organic pollution and rainfall on this very enclosed creek. Occasionally, short-lived high levels of nitrates were recorded at Marsaxlokk and Mistra bays. These seem to originate from agitation of bottom sediments.peer-reviewe

Rotenone-insensitive NAD(P)H dehydrogenases in plants: Immunodetection and distribution of native proteins in mitochondria.

Antisera produced against peptides deduced from potato nda1 and ndb1, homologues of yeast genes for mitochondrial rotenone-insensitive NADH dehydrogenases, recognise respective proteins upon expression in Escherichiacoli. In western blots of potato (Solanum tuberosum L.) mitochondrial proteins, the NDB and NDA antibodies specifically detect polypeptides of 61 and 48 kDa, respectively. The proteins are found in mitochondria of flowers, leaves and tubers. Different signal intensities are seen relative to other respiratory chain components when organs are compared, indicating variations in relative abundance of dehydrogenases within the plant. The antibodies detect single polypeptides, of similar size as in potato, in mitochondria from several plant species. No specific cross-reaction was found in chloroplasts, but a weak NDA signal of 50 kDa was found in microsomes, possibly associated with peroxisomes. Two- dimensional native/SDS-PAGE analyses indicate that both NDA and NDB proteins reside as higher molecular mass forms, possibly oligomeric. The NDB immunoreactive protein is released by sonication of mitochondria, but resistant to extraction by digitonin and partially to Triton X-100. In comparison, the NDA protein remains bound to the inner membrane at sonication or digitonin treatment, but can be solubilised with Triton. Investigation of a beetroot (Beta vulgaris L.) induction system for external NADH dehydrogenase indicates that the NDB antibody does not recognise the induced external NADH dehydrogenase in this species, but possibly an external NADPH dehydrogenase

The maritime heritage of Yemen: a focus on traditional wooden "dhows"

This paper investigates the disappearing heritage of Yemen’s large wooden boats (dhows), both in its current socio-economic context and in historical perspective. Fieldwork conducted by members of the MARES project in February 2009 along the coast between Aden and Salif sought to record remaining evidence of wooden boats and their related industries and practices. Wooden boat use has been in sharp decline in recent decades, as dhow-based commerce has declined, and fishing communities have switched to fibreglass vessels. The fieldwork sought to record remaining dhows through simple survey techniques including photography and illustration, as well as close observation. It also involved ethnographic interviews with people who worked on these vessels, either as builders or mariners. In terms of the vessels themselves, the aim was to produce a typology of Yemeni dhows; to record examples of each; to understand construction sequences; and to inventory the distribution of surviving craft. The findings are compared with previous literature on the subject.This research was conducted as part of the MARES Project, a three-year programme investigating the maritime past and heritage of the Red Sea and Arabian-Persian Gulf. MARES is based at the Institute of Arab and Islamic Studies of the University of Exeter (http://projects.exeter.ac.uk/mares). The programme is generously funded by the Golden Web Foundation, an educational charity registered in the UK (www.goldenweb.org). Thanks are also due to the Seven Pillars of Wisdom Trust, which provided additional financial support for the fieldwork. In addition, the MARES team would like to thank the following people for their assistance: Dr Abdulla M. Bawazir, President of Yemen’s General Organisation of Antiquities and Museums (GOAM); Dr Muhammad Taha al- Asbahi, General Director of Antiquities at GOAM; Dr Raja Batawil, head of GOAM in Aden; our GOAM-appointed field companion, Salah al-Mansuri; Mr. Hasan Saleh Shihab; Emily Allardyce, Fuad Mazid al-Matairi and their colleagues at the British Yemeni Language Institute; our driver and guide Muhammad al-Matairi; Edward Prados, Director of Amideast; Chris Evans; the British Council; and the British Embassy, Sanʿā. The team wishes to thank also the many individual informants along Yemen’s coast who generously gave of their time and expertise

Radiation therapy combined with intracerebral administration of carboplatin for the treatment of brain tumors

Background: In this study we determined if treatment combining radiation therapy (RT) with intracerebral (i.c.) administration of carboplatin to F98 glioma bearing rats could improve survival over that previously reported by us with a 15 Gy dose (5 Gy × 3) of 6 MV photons.Methods: First, in order to reduce tumor interstitial pressure, a biodistribution study was carried out to determine if pretreatment with dexamethasone alone or in combination with mannitol and furosemide (DMF) would increase carboplatin uptake following convection enhanced delivery (CED). Next, therapy studies were carried out in rats that had received carboplatin either by CED over 30 min (20 μg) or by Alzet pumps over 7 d (84 μg), followed by RT using a LINAC to deliver either 20 Gy (5 Gy × 4) or 15 Gy (7.5 Gy × 2) dose at 6 or 24 hrs after drug administration. Finally, a study was carried out to determine if efficacy could be improved by decreasing the time interval between drug administration and RT.Results: Tumor carboplatin values for D and DMF-treated rats were 9.4 ±4.4 and 12.4 ±3.2 μg/g, respectively, which were not significantly different (P = 0.14). The best survival data were obtained by combining pump delivery with 5 Gy × 4 of X-irradiation with a mean survival time (MST) of 107.7 d and a 43% cure rate vs. 83.6 d with CED vs. 30-35 d for RT alone and 24.6 d for untreated controls. Treatment-related mortality was observed when RT was initiated 6 h after CED of carboplatin and RT was started 7 d after tumor implantation. Dividing carboplatin into two 10 μg doses and RT into two 7.5 Gy fractions, administered 24 hrs later, yielded survival data (MST 82.1 d with a 25% cure rate) equivalent to that previously reported with 5 Gy × 3 and 20 μg of carboplatin.Conclusions: Although the best survival data were obtained by pump delivery, CED was highly effective in combination with 20 Gy, or as previously reported, 15 Gy, and the latter would be preferable since it would produce less late tissue effects.peer-reviewe

NAD(P) turnover in plant mitochondria

An analytical procedure based on alkaline extraction and HPLC analysis was adapted for quantification of pyridine nucleotides in plant mitochondria. The amounts of NAD and NADP extracted from seven different species varied from 1.0 to 3.7 and 0 to 0.5 nmol (mg protein) –1 , respectively. Although NADP was found in four species, its reduced form was in all cases below the detection limit of 0.1 nmol (mg protein) –1 . The NAD pool was mainly oxidized in the absence of substrates. However, oxidation of substrates followed by anaerobiosis caused 50–92% NAD pool reduction, indicating that the majority of the NAD+ was metabolically active. The NAD reduction level in potato tuber mitochondria oxidizing malate varied with assay conditions. The highest level of reduction (>80%) was reached at anaerobiosis, at pH 6.5 and 7.2, conditions favouring malic enzyme (ME), whereas the lowest reduction level (0%) was observed at pH 7.5, conditions favouring malate dehydrogenase (MDH). Mitochondria incubated at 0°C without respiratory substrate showed a loss of endogenous NAD + which correlated with a decline in the rate of oxidation of NAD+ -linked substrates. The lost NAD+ was mainly recovered as breakdown products in both the surrounding medium and the mitochondria. When submitochondrial fractions were incubated with NAD + or NADP + , the highest rate of NAD(P)+metabolism was detected in the outer membrane fraction. The metabolites detected, adenosine monophosphate (AMP), nicotinamide mononucleotide (NMN) and adenosine, imply that several enzymes involved in pyridine nucleotide degradation, including an NAD pyrophosphatase, are localized to the outer membrane

P 139 Serum dramatically enhances orientation and migration of cultured bovine corneal epithelial cells in an applied electric field (EF)

Digitalitzat per Artypla

An MPEG-7 scheme for semantic content modelling and filtering of digital video

Abstract Part 5 of the MPEG-7 standard specifies Multimedia Description Schemes (MDS); that is, the format multimedia content models should conform to in order to ensure interoperability across multiple platforms and applications. However, the standard does not specify how the content or the associated model may be filtered. This paper proposes an MPEG-7 scheme which can be deployed for digital video content modelling and filtering. The proposed scheme, COSMOS-7, produces rich and multi-faceted semantic content models and supports a content-based filtering approach that only analyses content relating directly to the preferred content requirements of the user. We present details of the scheme, front-end systems used for content modelling and filtering and experiences with a number of users