The Tsunami Threat to Sydney Harbour, Australia: Modelling potential and historic events.

Tsunami modelling of potential and historic events in Australia's Sydney Harbour quantifies the potentially damaging impacts of an earthquake generated tsunami. As a drowned river valley estuary exposed to distant source zones, these impacts are predominantly high current speeds (>2 m/s), wave amplification and rapid changes in water level. Significant land inundation only occurs for scenarios modelled with the largest waves (9.0 MW source). The degree of exposure to the open ocean and the geomorphology of locations within the Harbour determine the relative level of these impacts. Narrow, shallow channels, even those sheltered from the open ocean, create a bottleneck effect and experience the highest relative current speeds as well as elevated water levels. The largest maximum water levels (>8 m) occur in exposed, funnel-shaped bays and wave amplification is greatest at locations exposed to the open ocean: >7 times deep water wave heights for 9.0 MW source waves. Upstream attenuation rates of runup and maximum water level show a linear correlation with wave height parameters at the 100 m depth contour and may provide some predictive capabilities for potential tsunami impacts at analogous locations. In the event of a tsunami in Sydney Harbour, impacts may threaten marine traffic and infrastructure.

Knowledge of Down syndrome in pregnant women from different ethnic groups.

The uptake of any screening test is influenced by knowledge of the condition being screened for. In the present study, the knowledge and the source of knowledge of women offered antenatal screening for Down syndrome (DS) was assessed by means of a self-administered questionnaire. The questionnaire was administered to 300 consecutive women booking for antenatal care, of the 245 (82%) women who completed and returned the questionnaire, 117 (48%) were Caucasian, 85 (35%) were Asian born outside the UK, 32 (13%) were Asian born in the UK and ten (4%) belonged to other categories. Only 30% of the cohort had a good understanding of the condition. Racial groups other than Caucasian had a poorer understanding of DS. The factors which affected knowledge of DS included quality of spoken English, knowing an affected child, parity and religion. The most significant factor affecting acceptance of screening was the woman's knowledge of DS. The source of information for the condition varied widely: 42% from a general practitioners (GP), 24% from the hospital and 16% from midwives. The proportion with good knowledge was similar in those women whose source of information was the GP (45%) and the midwife (41%). These proportions were, however, higher (though not significantly) when the source of information was from magazines and newspapers (67%) and from friends (53%). Uptake of the screening test was best in those with good knowledge (53%) compared to those with poor knowledge (23%) (p<0.02). Between 28% and 66% (depending on the ethnic group) of women had a screening blood test "allegedly" without knowing why it had been performed. In order to improve uptake of the screening test for DS there is need for better education and counselling of women attending for antenatal care.

The effects of magnesium supplementation on exercise performance.

PURPOSE: To determine the effects of magnesium (Mg2+) supplementation on performance and recovery in physically active women using the sensitive and recently advanced measure of ionic Mg2+ (iMg). METHODS: Participants (N = 121) were screened for [iMg] in plasma, with 44 (36.4%) exhibiting [iMg] below the normal range of 0.53-0.67 mmol.L-1 (4). Thirty-two subjects (21 +/- 3 yr) representing a broad range of [iMg] (0.54 +/- 0.04 mmol.L-1) completed the main 14-wk study. At baseline, participants submitted to a resting blood pressure measurement, and they completed both an anaerobic treadmill test and an incremental (aerobic) treadmill test. For the latter, values for workload, oxygen uptake, and heart rate were obtained at both anaerobic threshold and maximal effort. Blood samples for iMg, total serum Mg2+ (TMg), erythrocyte Mg2+ (EMg), Ca2+, K+, Na+, hemoglobin, hematocrit, lactate, and glucose were also collected pretest, and 4, 10, 30 min, and 24 h posttest. Subjects received 212 mg.d-1 Mg oxide or placebo in a double-blind fashion and were retested after 4 wk. After a 6-wk washout period, the testing was repeated with a treatment crossover. RESULTS: Ionic Mg2+ increased with Mg2+ treatment versus placebo (P < 0.05); however, performance and recovery indices were not significantly affected. CONCLUSION: Four weeks of 212 mg.d-1 Mg oxide supplementation improves resting [iMg] levels but not performance or recovery in physically active women.

Genes and regulatory sites of the "host-takeover module" in the terminal redundancy of Bacillus subtilis bacteriophage SPO1.

Early in infection of Bacillus subtilis by bacteriophage SPO1, the synthesis of most host-specific macromolecules is replaced by the corresponding phage-specific biosyntheses. It is believed that this subversion of the host biosynthetic machinery is accomplished primarily by a cluster of early genes in the SPO1 terminal redundancy. Here we analyze the nucleotide sequence of this 11.5-kb "host-takeover module," which appears to be designed for particularly efficient expression. Promoters, ribosome-binding sites, and codon usage statistics all show characteristics known to be associated with efficient function in B. subtilis. The promoters and ribosome-binding sites have additional conserved features which are not characteristic of their host counterparts and which may be important for competition with host genes for the cellular biosynthetic machinery. The module includes 24 genes, tightly packed into 12 operons driven by the previously identified early promoters PE1 to PE12. The genes are smaller than average, with half of them having fewer than 100 codons. Most of their inferred products show little similarity to known proteins, although zinc finger, trans-membrane, and RNA polymerase-binding domains were identified. Transcription-termination and RNase III cleavage sites were found at appropriate locations.

A comparative study of women with chronic pelvic pain, chronic nonpelvic pain and those with no history of pain attending general practitioners.

OBJECTIVE: To investigate and compare the demographic and psychosocial profiles of women with chronic pelvic pain, chronic pain in a different site, and those with no history of pain with specific reference to a history of sexual abuse. DESIGN: A prospective comparative study. SETTING: Pelvic Pain Clinic at Leicester General Hospital NHS Trust, Pain Management Clinic at Leicester Royal Infirmary NHS Trust and two General Practices. PARTICIPANTS: Thirty women with chronic pelvic pain, 30 women with chronic pain in a different site and 30 women attending their general practitioner with no history of pain. INTERVENTIONS: A specifically designed patient profile questionnaire to identify and explore incidents of sexual and physical abuse was administered to each woman by a research psychologist for confidential self-completion. Data were also collected on other demographic, medical and psychosocial characteristics. RESULTS: Women with chronic pelvic pain were found to have a higher lifetime prevalence of sexual abuse, involving penetration or other genital contact compared with the two comparison groups. The prevalence of physical abuse was the same in all groups. Women in the pelvic pain group were more likely to have approached their GP for symptoms not related to pelvic pain than women in the other two groups and the incidence of clinical anxiety was significantly higher in this group compared with the pain-free group. The prevalence of sexual problems was much higher in the group with pelvic pain compared with the other two groups. CONCLUSION: These findings indicate that women with chronic pelvic pain have a higher incidence of past sexual abuse compared with women in a comparison pain group and with women with no pain.

Changes in Isozyme Profiles of Catalase, Peroxidase, and Glutathione Reductase during Acclimation to Chilling in Mesocotyls of Maize Seedlings.

The response of antioxidants to acclimation and chilling in various tissues of dark-grown maize (Zea mays L.) seedlings was examined in relation to chilling tolerance and protection from chilling-induced oxidative stress. Chilling caused an accumulation of H2O2 in both the coleoptile + leaf and the mesocotyl (but not roots), and acclimation prevented this accumulation. None of the antioxidant enzymes were significantly affected by acclimation or chilling in the coleoptile + leaf or root. However, elevated levels of glutathione in acclimated seedlings may contribute to an enhanced ability to scavenge H2O2 in the coleoptile + leaf. In the mesocotyl (visibly most susceptible to chilling), catalase3 was elevated in acclimated seedlings and may represent the first line of defense from mitochondria-generated H2O2. Nine of the most prominent peroxidase isozymes were induced by acclimation, two of which were located in the cell wall, suggesting a role in lignification. Lignin content was elevated in mesocotyls of acclimated seedlings, likely improving the mechanical strength of the mesocotyl. One cytosolic glutathione reductase isozyme was greatly decreased in acclimated seedlings, whereas two others were elevated, possibly resulting in improved effectiveness of the enzyme at low temperature. When taken together, these responses to acclimation illustrate the potential ways in which chilling tolerance may be improved in preemergent maize seedlings.

Localization and Characterization of Peroxidases in the Mitochondria of Chilling-Acclimated Maize Seedlings.

We present evidence of two peroxidases in maize (Zea mays L.) mitochondria. One of these uses guaiacol and the other uses cytochrome c as the electron donor. Treatments of fresh mitochondria with protease(s) indicate that ascorbate and glutathione peroxidases are likely bound to the mitochondria as cytosolic contaminants, whereas guaiacol and cytochrome peroxidases are localized within the mitochondria. These two mitochondrial peroxidases are distinct from contaminant peroxidases and mitochondrial electron transport enzymes. Cytochrome peroxidase is present within the mitochondrial membranes, whereas guaiacol peroxidase is loosely bound to the mitochondrial envelope. Unlike other cellular guaiacol peroxidases, mitochondrial guaiacol peroxidase is not glycosylated. Digestion of lysed mitochondria with trypsin activated mitochondrial guaiacol peroxidase but inhibited cytochrome peroxidase. Isoelectric focusing gel analysis indicated guaiacol peroxidase as a major isozyme (isoelectric point 6.8) that is also activated by trypsin. No change in the mobility of guaiacol peroxidase due to trypsin treatment on native polyacrylamide gel electrophoresis was observed. Although both peroxidases are induced by chilling acclimation treatments (14[deg]C), only cytochrome peroxidase is also induced by chilling (4[deg]C). Because chilling induces oxidative stress in the maize seedlings and the mitochondria are a target for oxidative stress injury, we suggest that mitochondrial peroxidases play a role similar to catalase in protecting mitochondria from oxidative damage.

Genes that protect against the host-killing activity of the E3 protein of Bacillus subtilis bacteriophage SPO1.

A cloned rpoB gene, specifying an apparently mutant RNA polymerase beta subunit, protected Escherichia coli against the cytocidal effects of the E3 protein of bacteriophage SPO1, suggesting that RNA polymerase is the primary cellular target of the E3 protein. Two segments of the wild-type E. coli genome, one of which specifies a suppressor of dnaK mutations, and thus, possibly, a molecular chaperone, also provided protection when overexpressed, but wild-type rpoB did not.

Acclimation, Hydrogen Peroxide, and Abscisic Acid Protect Mitochondria against Irreversible Chilling Injury in Maize Seedlings.

Our previous results indicated that 3-d-old dark-grown chilling-sensitive maize (Zea mays L.) seedlings did not survive 7 d of 4[deg]C chilling stress, but 69% of them survived similar stress when the seedlings were either preexposed to 14[deg]C for 3 d or pretreated with 0.1 mM H2O2 for 4 h at 27[deg]C (T.K. Prasad, M.D. Anderson, B.A. Martin, C.R. Stewart [1994] Plant Cell 6: 65-74) or 1 mM abscisic acid (ABA) for 24 h at 27[deg]C (M.D. Anderson, T.K. Prasad, B.A. Martin, C.R. Stewart [1994] Plant Physiol 105: 331-339). We discovered that chilling imposed oxidative stress on the seedlings. Since H2O2 accumulated during the periods of both acclimation and nonacclimation, we concluded that H2O2 had dual effects at low temperature: (a) During acclimation, its early transient accumulation signals the induction of antioxidant enzymes such as catalase 3 and peroxidase to scavenge H2O2; and (b) at 4[deg]C in nonacclimated seedlings, it accumulates to damaging levels in the tissues because of low levels of these and perhaps other antioxidant enzymes. Three-day-old seedlings pretreated with H2O2 (a mild oxidative stress) or ABA showed induced chilling tolerance. In the present study, we investigated whether mitochondria are a target for chilling-induced oxidative stress and, if so, what differences do acclimation, H2O2, or ABA make to protect mitochondria from irreversible chilling injury. The results indicated that chilling, in general, impairs respiratory activity, the cytochrome pathway of electron transport, and ATPase activity regardless of the treatment. In pretreated seedlings, the activities of catalase 3 and peroxidase in the mitochondria increased severalfold compared with control and nonacclimated seedlings. The increases in these antioxidant enzymes imply that mitochondria are under oxidative stress and such increases could initiate a protective mechanism in the mitochondria. Mitochondrial respiration is partially cyanide resistant during chilling stress and also after the 1st d of recovery. Upon further recovery over 3 d, in contrast to nonacclimated seedlings, the mitochondria of acclimation-, H2O2-, and ABA-treated seedlings showed the following recovery features. (a) The mitochondrial respiration changed from a cyanide-resistant to a cyanide-sensitive cytochrome pathway, (b) cytochrome oxidase activity recovered to control levels, (c) the ability of mitochondria to generate ATP was regained, and (d) the antioxidant enzyme activities remained at or above control levels. Based on these results, we conclude that chilling impairs mitochondrial function and that chilling-induced oxidative stress seems to be a factor, at least in part, for causing possible irreversible damage to the mitochondrial membrance components. Acclimation, H2O2, and ABA provide a protective mechanism by inducing antioxidant enzymes to protect mitochondria from irreversible oxidative damage that is absent in nonacclimated seedlings. Therefore, we conclude that the ability of the seedlings to recover from chilling injury is, at least in part, due to the ability of the mitochondria to resume normal function.

Infertility, obstetric and gynaecological problems in coeliac sprue.

There is now substantial evidence that coeliac sprue is associated with infertility both in men and women. In women it can also lead to delayed menarche, amenorrhoea, early menopause, recurrent abortions, and a reduced pregnancy rate. In men it can cause hypogonadism, immature secondary sex characteristics and reduce semen quality. The real mechanism by which coeliac sprue produces these changes is unclear, but factors such as malnutrition, iron, folate and zinc deficiencies have all been implicated. In addition in men gonadal dysfunction is believed to be due to reduced conversion of testosterone to dihydrotestosterone caused by low levels of 5 alpha-reductase in coeliac sprue. This leads to derangement of the hypothalamic-pituitary axis. Hyperprolactinaemia is seen in 25% of coeliac patients, which causes impotence and loss of libido. Gluten withdrawal and correction of deficient dietary elements can lead to a return of fertility both in men and women.

Differential Gene Expression in Chilling-Acclimated Maize Seedlings and Evidence for the Involvement of Abscisic Acid in Chilling Tolerance.

An acclimation phenomenon was characterized in seedlings of chilling-sensitive maize (Zea mays L.) inbred G50 (Pioneer). Seedlings were germinated at 27[deg]C for 3 d and then exposed to chilling treatments of 4, 5, or 6[deg]C for 2, 4, 7, or 10 d in darkness. Damage symptoms in the more severe treatments included a waterlogged appearance and a discoloration of the tissue. The symptoms were most obvious in the mesocotyl. After a 10-d grow-out period in the greenhouse, moderately damaged seedlings exhibited chlorotic areas, an occasional disruption in leaf expansion, and a constriction of the mesocotyl. Growth and survival were improved by first exposing seedlings to a 14[deg]C acclimation treatment for 3 d before applying the chilling treatment. After chilling at 5[deg]C for 7 d, 79% of the acclimated seedlings survived, whereas only 22% of the nonacclimated seedlings survived. Differences in gene expression between acclimated and control seedlings were investigated using subtraction and differential screening techniques. Transcripts corresponding to three genes, car333, car30, and car757 (chilling acclimation responsive), were present in higher levels in seedlings after acclimation. Sequence analysis identified car333 as cat3, which encodes maize mitochondrial catalase isozyme 3. Characterization of these three clones revealed that all corresponding transcripts were elevated in acclimated seedlings in a manner that depended on the organ, i.e. coleoptile, mesocotyl, or root. Although transcripts were elevated in all three organs in response to acclimation, car30 was most abundant in the coleoptile and root, whereas cat3 and car757 were most abundant in the coleoptile and mesocotyl. Catalase activity followed the same general trend as cat3 transcript levels. Exogenous treatment with abscisic acid (ABA) resulted in an improvement in growth and survival of nonacclimated, chilled seedlings. Inhibition of ABA biosynthesis with fluridone abolished acclimation-induced chilling tolerance, and exogenous application of ABA to fluridone-treated seedlings restored chilling tolerance. Exogenous ABA treatment also resulted in increases in cat3, car30, and car757 transcript levels and catalase activity in the same organ-specific manner as in acclimated seedlings. These results indicate that ABA synthesis is essential for chilling tolerance. However, measurement of ABA levels in mesocotyls during acclimation and chilling revealed only a marginal increase during acclimation and a dramatic increase during chilling, regardless of whether or not seedlings were acclimated. Thus, although ABA may be required for chilling tolerance, we have no conclusive evidence that the acclimation process is mediated by ABA.

Evidence for Chilling-Induced Oxidative Stress in Maize Seedlings and a Regulatory Role for Hydrogen Peroxide.

We have taken advantage of an acclimation phenomenon in a chilling-sensitive maize inbred to investigate the molecular, biochemical, and physiological responses to chilling in preemergent maize seedlings. Three-day-old seedlings were exposed to 4[deg]C for 7 days and did not survive chilling stress unless they were preexposed to 14[deg]C for 3 days. cDNAs representing three chilling acclimation-responsive (CAR) genes were isolated by subtraction hybridization and differential screening and found to be differentially expressed during acclimation. Identification of one of these CAR genes as cat3, which encodes the mitochondrial catalase3 isozyme, led us to hypothesize that chilling imposes oxidative stress in the seedlings. Hydrogen peroxide levels were elevated during both acclimation and chilling of nonacclimated seedlings. Further molecular and biochemical analyses indicated that whereas superoxide dismutase activity was not affected, the levels of cat3 transcripts and the activities of catalase3 and guaiacol peroxidase were elevated in mesocotyls during acclimation. Accumulation of H2O2 following a short treatment with aminotriazole, a catalase inhibitor, indicated that catalase3 seems to be an important H2O2-scavenging enzyme in the seedlings. Control 3-day-old seedlings pretreated with H2O2 or menadione, a superoxide-generating compound, at 27[deg]C induced chilling tolerance. Both of these chemical treatments also increased cat3 transcripts and catalase3 and guaiacol peroxidase activities. We suggest that peroxide has dual effects at low temperatures. During acclimation, its early accumulation signals the production of antioxidant enzymes such as catalase3 and guaiacol peroxidase. At 4[deg]C, in nonacclimated seedlings, it accumulates to damaging levels in the tissues due to low levels of these, and perhaps other, antioxidant enzymes.

A cytotoxic early gene of Bacillus subtilis bacteriophage SPO1.

Some of the early genes of Bacillus subtilis bacteriophage SPO1 were hypothesized to function in the shutoff of host biosyntheses. Two of these genes, e3 and e22, were cloned and sequenced. E22 showed no similarity to any known protein, while E3, a highly acidic protein, showed significant similarity only to other similarly acidic proteins. Each gene was immediately downstream of a very active early promoter. Each was expressed actively during the first few minutes of infection and was then rapidly shut off and its RNA rapidly degraded. An e3 nonsense mutation severely retarded the degradation of e3 RNA. Expression of a plasmid-borne e3 gene, in either B. subtilis or Escherichia coli, resulted in the inhibition of host DNA, RNA, and protein syntheses and prevented colony formation. However, the e3 nonsense mutation caused no measurable decrease in either burst size or host shutoff during infection and, in fact, caused an increased burst size at high multiplicities of infection. We suggest that e3 is one of several genes involved in host shutoff, that its function is dispensable both for host shutoff and for phage multiplication, and that its shutoff function is not entirely specific to host activities.

Proptosis as a presenting sign of extradural haematoma.

A conscious 15-year-old boy presented with progressive proptosis and a severe headache 2 weeks after minor blunt trauma to the head. No neurological deficit was present. Computed tomography demonstrated intracranial and intraorbital cyst-like masses. At craniotomy a subacute extradural haematoma was found which communicated with an orbital subperiosteal haematoma through a shelved orbital roof fracture. The haematomas were drained and the patient made an uneventful postoperative recovery. Although rare, an extradural haemorrhage should be considered in any patient presenting to an ophthalmologist with progressive proptosis and headache following a head injury.

Effect of Exogenous Abscisic Acid on Proline Dehydrogenase Activity in Maize (Zea mays L.).

Plant responses to drought stress include proline and abscisic acid (ABA) accumulation. Proline dehydrogenase (PDH) (EC 1.4.3) is the first enzyme in the proline oxidation pathway, and its activity has been shown to decline in response to water stress (PJ Rayapati, CR Stewart [1991] Plant Physiol 95: 787-791). In this investigation, we determined whether ABA treatment affects PDH activity in a manner similar to drought stress in maize (Zea mays L.) seedlings. Four exogenous ABA treatments (0, 11, 33, and 100 micromolar ABA) were applied to well-watered maize seedlings. Mitochondria were isolated and PDH was solubilized using Nonidet P-40. PDH activity was measured by the reduction of iodonitrotetrazolium violet under proline-dependent conditions. There was no effect of ABA on PDH activity at 33 and 100 micromolar ABA, but there was a 38% decline at 11 micromolar. This decline was less than the 69% reduction in activity under drought stress. Endogenous ABA determinations and plant growth rate showed that ABA entered the plant and was affecting metabolic processes. ABA treatments had a small effect on shoot and root proline concentration, whereas drought stress caused a 220% increase in root tissues. We conclude that ABA is not part of the pathway linking drought stress and decreased PDH activity.

cDNA clones encoding Arabidopsis thaliana and Zea mays mitochondrial chaperonin HSP60 and gene expression during seed germination and heat shock.

Mitochondria contain a nuclear-encoded heat shock protein, HSP60, which functions as a chaperonin in the post-translational assembly of multimeric proteins encoded by both nuclear and mitochondrial genes. We have isolated and sequenced full-length complementary DNAs coding for this mitochondrial chaperonin in Arabidopsis thaliana and Zea mays. Southern-blot analysis indicates the presence of a single hsp60 gene in the genome of A. thaliana. There is a high degree of homology at the predicted amino acid levels (43 to 60%) between plant HSP60s and their homologues in prokaryotes and other eukaryotes which indicates that these proteins must have similar evolutionarily conserved functions in all organisms. Northern- and western-blot analyses indicate that the expression of the hsp60 gene is developmentally regulated during seed germination. It is also heat-inducible. Developmental regulation of the (beta-subunit of F1-ATPase, an enzyme complex that is involved in the cyanide-sensitive mitochondrial electron transport system, indicates that imbibed embryos undergo rapid mitochondrial biogenesis through the early stages of germination. Based on the functional role of HSP60 in macromolecular assembly, these data collectively suggest that the presence of higher levels of HSP60 is necessary during active mitochondrial biogenesis, when the need for this protein is greatest in assisting the rapid assembly of the oligomeric protein structures.

Photosynthesis and photorespiration in presenescent, senescent, and rejuvenated soybean cotyledons.

Various growth and physiological parameters were measured in germinating, presenescent, and senescing soybean (Glycine max [L.] Merr.) cotyledons and in cotyledons rejuvenated by epicotyl removal 18 days after planting. The maximal measured carbon dioxide exchange rates (CER) in the cotyledons were in the range of those reported for field-grown soybean leaves. Rejuvenated cotyledons accumulated total chlorophyll in excess of the maximum observed in presenescent cotyledons. When photosynthetic rates were expressed per cotyledon, the CER in rejuvenated tissue recovered to the maximal rates observed in presenescent cotyledons. Ribulose-1,5-bisphosphate carboxylase/oxygenase in rejuvenated cotyledons also recovered to the maximal amount seen in presenescent cotyledons so that CER appeared to be a function of ribulose-1,5-bisphosphate carboxylase/oxygenase content during most of the period studied. Observations of the postillumination outburst of CO(2) and (14)C label in glycine indicated that photorespiration was occurring in the cotyledons and that photorespiration relative to photosynthesis was different in rejuvenated compared with presenescent cotyledons.

Solubilization of a Proline Dehydrogenase from Maize (Zea mays L.) Mitochondria.

L-Proline is oxidized to pyrroline-5-carboxylic acid in intact plant mitochondria by a proline dehydrogenase (EC 1.4.3) that is bound to the matrix side of the inner mitochondrial membrane (TE Elthon, CR Stewart [1981] Plant Physiol 67: 780-784). This investigation reports the first solubilization of the L-proline dehydrogenase (PDH) from plant mitochondria. The supernatant from NP-40-treated etiolated shoot mitochondria of maize, Zea mays L., reduced iodonitrotetrazolium violet in a proline dependent manner. The pH optimum for this activity was 8. The apparent K(m) for proline was 6.6 millimolar. When supplied with proline, this solubilized PDH activity also synthesized pyrroline-5-carboxylic acid. The PDH activity was inhibited in vitro by 300 millimolar potassium chloride but not by 300 millimolar potassium acetate. The PDH activity had a molecular mass that was greater than 150 kilodaltons. Mitochondria were prepared from etiolated shoots grown in 100% water-saturated vermiculite (control) and 16% water-saturated vermiculite (stress). The specific activity of solubilized PDH from the stress treatment was 11% of the same activity from the control treatment. Oxygen uptake in the presence of proline and ADP (state 3 proline oxidation) by mitochondria from the stress treatment was 25% of the same rate by mitochondria from the control treatment. Mitochondria were also prepared 16 hours after rewatering the seedlings growing in the stress treatment. Both the solubilized PDH specific activity and state 3 proline oxidation returned to the control levels. The specific activities of the NAD(+)-dependent pyrroline-5-carboxylic acid dehydrogenase and cytochrome c oxidase in the solubilized preparations were unaffected by these stress and recovery treatments. Oxygen uptake rates by intact mitochondria in the presence of ADP and NADH, succinate or malate-pyruvate were also unaffected by these treatments.