A carbonic anhydrase inhibitor induces bicarbonate-reversible suppression of electron transfer in pea photosystem 2 membrane fragments

The effects of suppression of the carbonic anhydrase (CA) activity by a CA-inhibitor, acetazolamide (AA), on the photosynthetic activities of photosystem II (PS II) particles from higher plants were investigated. AA along with CA-activity inhibits the PS II photosynthetic electron transfer and the AA-induced suppression is totally reversed by the addition of bicarbonate (3-5 mM). Similar effect of recovery in the PS II photosynthetic activity was also revealed upon the addition of known artificial electron donors (potassium ferrocyanide and TMPD). Significance and possible functions of CA for the PS II donor side are discussed.

Incidence and risk factors for depression and anxiety disorders: results from a 34-year longitudinal Swedish cohort study

This study is based on a total cohort (N = 192) of people born in 1902 and 1903 and living in southern Sweden. Subjects were assessed at baseline when 67 years of age and on eight further occasions over 34 years or until death. The participation rate in the nine examinations ranged from 78-100%. Interviews, psychological tests, and medical examinations were used as well as information on medical diagnoses from primary health care records and hospital records. The cumulative probability for the development of clinical depression during the follow-up was 8% and for anxiety 6%. The incidence rate for depression and for anxiety was highest during the period 67-81 years. Persons with poor financial status were more likely to be diagnosed with depression but no significant risk factor for anxiety was found. Only 14% developed depression and anxiety during the follow-up period, females more often than men. The strongest risk factors for the development of depression were perceived economic problems.

Carbonic anhydrase activities in pea thylakoids

Pea thylakoids with high carbonic anhydrase (CA) activity (average rates of 5000 micromol H(+) (mg Chl)(-1) h(-1) at pH 7.0) were prepared. Western blot analysis using antibodies raised against the soluble stromal beta-CA from spinach clearly showed that this activity is not a result of contamination of the thylakoids with the stromal CA but is derived from a thylakoid membrane-associated CA. Increase of the CA activity after partial membrane disintegration by detergent treatment, freezing or sonication implies the location of the CA in the thylakoid interior. Salt treatment of thylakoids demonstrated that while one part of the initial enzyme activity is easily soluble, the rest of it appears to be tightly associated with the membrane. CA activity being measured as HCO(3) (-) dehydration (dehydrase activity) in Photosystem II particles (BBY) was variable and usually low. The highest and most reproducible activities (approximately 2000 micromol H(+) (mg Chl)(-1) h(-1)) were observed in the presence of detergents (Triton X-100 or n-octyl-beta-D-glucopyranoside) in low concentrations. The dehydrase CA activity of BBY particles was more sensitive to the lipophilic CA inhibitor, ethoxyzolamide, than to the hydrophilic CA inhibitor, acetazolamide. CA activity was detected in PS II core complexes with average rate of 13,000 micromol H(+) (mg Chl)(-1) h(-1) which was comparable to CA activity in BBY particles normalized on a PS II reaction center basis.

The gender differences in growth hormone-binding protein and leptin persist in 80-year-old men and women and is not caused by sex hormones

OBJECTIVE

Leptin and growth hormone-binding protein (GHBP) both show gender differences that might be explained by sex hormones. To study the potential relevance of oestradiol and testosterone, we have examined 80-year-old subjects in whom oestradiol is higher in men than in women. The interrelationships between leptin, insulin, GHBP and fat mass in this age group were also investigated.

DESIGN AND SUBJECTS

Ninety-four subjects (55 females and 39 males), all 80 years old, were investigated in a community-based study. None of the investigated subjects was being treated for diabetes mellitus and none of the women had oestrogen replacement.

METHODS

Levels of testosterone, oestradiol, SHBG, IGF-I, GHBP, glucose, insulin and leptin were analysed. Body composition was measured with bioimpedance analysis (BIA).

RESULTS

As in younger age groups, serum leptin, the ratio leptin/kilogram fat mass and serum GHBP were higher in the women (all, P< or =0.007), although serum oestradiol was higher in the men (P<0.001). There were no significant associations between sex hormones and leptin or GHBP either in women or in men (all, r<0.13, P>0.1). Leptin correlated to kilogram fat mass in both women (r=0.55, P<0.001) and men (r=0.47, P=0.003), but in contrast, there were no significant correlations between GHBP and fat mass and GHBP and IGF-I, either in women or in men (all, r<0.24, P>0.2). Insulin and leptin were significantly associated with GHBP, both in women (r=0.48, P<0.001 and r=0.43, P=0.001, respectively) and in men (r=0.40, P=0.01 and r=0.34, P=0.03, respectively).

CONCLUSIONS

Although the 80-year-old men had higher oestradiol levels than the women, the women had higher levels of leptin and GHBP. There were no correlations between sex hormones and leptin and GHBP, which indicates that the gender differences are not caused by sex hormones in old age. In contrast to studies in younger subjects, GHBP did not correlate to fat mass in the investigated 80-year-old men and women. In the older subjects investigated, as in younger subjects, GHBP was significantly correlated with leptin and insulin.

The Chlamydomonas reinhardtii cia3 mutant lacking a thylakoid lumen-localized carbonic anhydrase is limited by CO2 supply to rubisco and not photosystem II function in vivo

The Chlamydomonas reinhardtii cia3 mutant has a phenotype indicating that it requires high-CO(2) levels for effective photosynthesis and growth. It was initially proposed that this mutant was defective in a carbonic anhydrase (CA) that was a key component of the photosynthetic CO(2)-concentrating mechanism (CCM). However, more recent identification of the genetic lesion as a defect in a lumenal CA associated with photosystem II (PSII) has raised questions about the role of this CA in either the CCM or PSII function. To resolve the role of this lumenal CA, we re-examined the physiology of the cia3 mutant. We confirmed and extended previous gas exchange analyses by using membrane-inlet mass spectrometry to monitor(16)O(2),(18)O(2), and CO(2) fluxes in vivo. The results demonstrate that PSII electron transport is not limited in the cia3 mutant at low inorganic carbon (Ci). We also measured metabolite pools sizes and showed that the RuBP pool does not fall to abnormally low levels at low Ci as might be expected by a photosynthetic electron transport or ATP generation limitation. Overall, the results demonstrate that under low Ci conditions, the mutant lacks the ability to supply Rubisco with adequate CO(2) for effective CO(2) fixation and is not limited directly by any aspect of PSII function. We conclude that the thylakoid CA is primarily required for the proper functioning of the CCM at low Ci by providing an ample supply of CO(2) for Rubisco.

Comparative studies on the properties of the extrinsic manganese-stabilizing protein from higher plants and of a synthetic peptide of its C-terminus

The present study describes a comparative analysis on the fluorescence properties of the manganese-stabilizing protein (MSP), a synthetic peptide corresponding to its C terminus and a 7:1 (molar ratio) mixture of N-acetyl-tyrosine and N-acetyl-tryptophan, respectively, together with reconstitution experiments of oxygen evolution in MSP-depleted photosystem II (PS II) membrane fragments. It is found: (i) at neutral pH, the fluorescence from Trp(241) is strongly diminished in MSP solutions, whereas it highly dominates the overall emission from the C-terminus peptide; (ii) at alkaline pH, the emission of Tyr and Trp is quenched in both, MSP and C-terminus peptide, with increasing pH but the decline curve is shifted by about two pH units towards the alkaline region in MSP; (iii) a drastically different pattern emerges in the 7:1 mixture where the Trp emission even slightly increases at high pH; (iv) the anisotropy of the fluorescence emission is wavelength-independent (310-395 nm) and indicative of one emitter type (Trp) in the C-terminus peptide and of two emitter types (Tyr, Trp) in MSP; and (v) in MSP-depleted PS II membrane fragments the oxygen evolution is restored (up to 85% of untreated control) by rebinding of MSP but not by the C-terminus peptide, however, the presence of the latter diminishes the restoration effect of MSP. A quenching mechanism of Trp fluorescence by a next neighbored tyrosinate in the peptide chain is proposed and the relevance of the C terminus of MSP briefly discussed.

Formal support, mental disorders and personal characteristics: a 25-year follow-up study of a total cohort of older people

The present study was designed to describe the pattern of long-term formal support received by people with mental disorders, and to investigate the relationship between the medical, psychological and social characteristics of the participants and types of formal support. This study is based on a cohort (n = 192) of people born in 1902 and 1903 in a community in Southern Sweden. The research participants were assessed using interviews, psychological tests and medical examinations. Information was collected about the use of primary healthcare and social services. The first assessment took place when the cohort was aged 67 years, and then on eight further occasions until they were 92. The participation rate ranged from 72% to 100%. During the observation period of 25 years, 53% of people with dementia eventually received both home help and institutional care compared to 34% of people with other psychiatric diagnoses and 12% of people with good mental health. The last group had all physical health problems and/or problems with activities of daily living. However, 35% of the dementia group, 46% with other psychiatric diagnoses and 52% of people with good mental health did not receive any formal support. Males and self-employed people were significantly less likely to use formal support. The institutionalised group reported loneliness significantly more often than the other two groups. In a logistic regression analysis, loneliness, low social class, high blood pressure and low problem-solving ability were predictors of formal support use. People with a mental disorder, including dementia, were significantly more likely to use formal support compared to people with good mental health. Social factors were the main factors predicting formal support.

Small, novel proteins from the mistletoe Phoradendron tomentosum exhibit highly selective cytotoxicity to human breast cancer cells

Four novel proteins (phoratoxins C-F) have been isolated from the North American mistletoe Phoradendron tomentosum. The amino acid sequences of these phoratoxins were determined unambiguously using a combination of Edman degradation and trypsin enzymatic digestion, and by electrospray ionization tandem mass spectrometry sequencing. Phoratoxins C, E and F consist of 46 amino acid residues; and phoratoxin D of 41. All proteins had six cysteines, similar to the earlier described phoratoxins A and B, which are thionins. The cytotoxicity of each protein was evaluated in a human cell line panel that represented several cytotoxic drug-resistance mechanisms. For the half-maximal inhibitory concentrations (IC50 values) of the different cell lines in the panel, correlation with those of standard drugs was low. The most potent cytotoxic phoratoxin C was further tested on primary cultures of human tumor cells from patients. The solid tumor samples from breast cancer cells were 18 times more sensitive to phoratoxin C than the tested hematological tumor samples.

Client expectations and satisfaction of quality in home care services. A consumer perspective

This study examines clients' expectations of quality in home care services and their perceived satisfaction with services among a random sample of 76 home care recipients in Vancouver, Canada. The researchers conducted face-to-face interviews that applied Multiattribute Utility Technology, a procedure that organizes several quality attributes of "ideal" home care into a tree structure to compare their relative importance and ranking from the clients' perspective. Participants also were asked to state their satisfaction or dissatisfaction with the services received in these domains. Among the five main quality attributes identified, the subjects ranked suitability of the home helper and its subset, personal competence, as the most important indicators of quality, followed by continuity in service. In addition, clients tended to have a high level of satisfaction with regard to the attributes of overall home care services. The highest level of satisfaction was reported for elements of personal dispositions of home care staff. The lowest level of satisfaction involved the time/availability components of the service. Finally, comparisons between client expectations and satisfaction of received home care services showed the highest discrepancy for the attributes of influence and time/availability and the greatest congruence for personal attributes of the staff. The results are discussed in terms of their implications for the delivery of home care services.

Concentrations of plasma methylmalonic acid in 80-year-olds show only weak relation to psychological performance

Most studies of the relation between psychological performance in the elderly and deficiencies of cobalamin and folate have used methods that determine the blood concentrations of these vitamins, which might not reflect the vitamin status in the tissues. Recently, two new markers, plasma homocysteine and methylmalonic acid, have attracted growing interest since they are considered to reflect the status of cobalamins and folates in the tissues. In a previous study, we noted a strong association between five parameters of well-being and lower concentrations of plasma homocysteine. In the present study, we have extended these observations by determination of plasma methylmalonic acid in the same healthy elderly population. In the present study, 18 out of 100 subjects had increased plasma methylmalonic acid and in 7 of these subjects, the concentrations of serum cobalamin, blood folate, plasma homocysteine and serum creatinine were within normal limits. The relation between plasma methylmalonic acid concentrations and concentrations of serum cobalamin and blood folates and five parameters of well-being were investigated. Concentrations of plasma methylmalonic acid were only weakly associated with the concentrations of serum cobalamin and lower scores on the logical reasoning test. The present study clearly shows that the levels of plasma methylmalonic acid show a much lesser association with the parameters of well-being than did plasma homocysteine.

Social relationships and health as predictors of life satisfaction in advanced old age: results from a Swedish longitudinal study

This longitudinal study examines the relationship between family and friend social support, health, and life satisfaction for a single cohort of eighty-year-old persons living in Lund, Sweden. Results indicate that participants who remained in the study are healthier and score higher on life satisfaction when compared with those who either drop-out or die prior to age eighty-three. Even though well-integrated with family and friends, the number of friends decreases significantly from eighty to eighty-three years; those who reported no close friends nearly doubled from eighty to eighty-three years. However, for those with close friends, contact with friends increases with age. In contrast to previous research, a correlational analysis indicates that neither child nor friend support is related to life satisfaction at either eighty or eighty-three years. However, health measures and satisfaction with sibling contact are related to total life satisfaction at age eighty-three only. These findings indicate the multidimensionality of both social support and life satisfaction for the old-old.

Role of a novel photosystem II-associated carbonic anhydrase in photosynthetic carbon assimilation in Chlamydomonas reinhardtii

Intracellular carbonic anhydrases (CA) in aquatic photosynthetic organisms are involved in the CO2-concentrating mechanism (CCM), which helps to overcome CO2 limitation in the environment. In the green alga Chlamydomonas reinhardtii, this CCM is initiated and maintained by the pH gradient created across the chloroplast thylakoid membranes by photosystem (PS) II-mediated electron transport. We show here that photosynthesis is stimulated by a novel, intracellular alpha-CA bound to the chloroplast thylakoids. It is associated with PSII on the lumenal side of the thylakoid membranes. We demonstrate that PSII in association with this lumenal CA operates to provide an ample flux of CO2 for carboxylation.

Insomnia in an 80-year-old population: relationship to medical, psychological and social factors

In this study, insomnia in 80-year-olds was related to medical, psychological and social factors. The data were based on examinations every year in people aged between 80 and 89 years. Of 333 people living in the city of Lund and born in 1908, 67% participated. Increased severity of insomnia was significantly associated with use of diuretics, other cardiovascular drugs, hypnotics and laxatives, and with nervousness, difficulty relaxing, anorexia, nausea, constipation, backache, feeling cold, sweating, loss of weight, dizziness, depression, general fatigue, exhaustion, angina pectoris, cardiac insufficiency, worsened objective and subjective health, presence of negative T-waves on ECG, anxiety, total life satisfaction, neuroticism, disbelief in a just world, feeling lonely and lower survival rates. Thus insomnia has widespread associations with different aspects of life in 80-year-olds.

Intracellular beta-carbonic anhydrase of the unicellular green alga Coccomyxa. Cloning of the cdna and characterization of the functional enzyme overexpressed in Escherichia coli

Carbonic anhydrase (CA) (EC 4.2.1.1) enzymes catalyze the reversible hydration of CO2, a reaction that is important in many physiological processes. We have cloned and sequenced a full-length cDNA encoding an intracellular beta-CA from the unicellular green alga Coccomyxa. Nucleotide sequence data show that the isolated cDNA contains an open reading frame encoding a polypeptide of 227 amino acids. The predicted polypeptide is similar to beta-type CAs from Escherichia coli and higher plants, with an identity of 26% to 30%. The Coccomyxa cDNA was overexpressed in E. coli, and the enzyme was purified and biochemically characterized. The mature protein is a homotetramer with an estimated molecular mass of 100 kD. The CO2-hydration activity of the Coccomyxa enzyme is comparable with that of the pea homolog. However, the activity of Coccomyxa CA is largely insensitive to oxidative conditions, in contrast to similar enzymes from most higher plants. Fractionation studies further showed that Coccomyxa CA is extrachloroplastic.

A novel alpha-type carbonic anhydrase associated with the thylakoid membrane in Chlamydomonas reinhardtii is required for growth at ambient CO2

A 29.5 kDa intracellular alpha-type carbonic anhydrase, designated Cah3, from the unicellular green alga Chlamydomonas reinhardtii is the first of this type discovered inside a photosynthetic eukaryote cell. We describe the cloning of a cDNA which encodes the protein. Immunoblot studies with specific antibodies raised against Cah3 demonstrate that the polypeptide is associated exclusively with the thylakoid membrane. The putative transit peptide suggests that Cah3 is directed to the thylakoid lumen, which is confirmed further by the presence of mature sized Cah3 after thermolysin treatment of intact thylakoids. Complementation of the high inorganic carbon concentration-requiring mutant, cia-3, with a subcloned cosmid containing the cah3 gene yielded transformants that grew on atmospheric levels of CO2 (0.035%) and contained an active 29.5 kDa alpha-type carbonic anhydrase. Although, cia-3 has reduced internal carbonic anhydrase activity, unexpectedly the level of Cah3 was similar to that of the wild-type, suggesting that the mutant accumulates an inactive Cah3 polypeptide. Genomic sequence analysis of the mutant revealed two amino acid changes in the transit peptide. Results from photosynthesis and chlorophyll a fluorescence parameter measurements show that the cia-3 mutant is photosynthetically impaired. Our results indicate that the carbonic anhydrase, extrinsically located within the chloroplast thylakoid lumen, is essential for growth of C.reinhardtii at ambient levels of CO2, and that at these CO2 concentrations the enzyme is required for optimal photosystem II photochemistry.

Induction and Regulation of Expression of a Low-CO2-Induced Mitochondrial Carbonic Anhydrase in Chlamydomonas reinhardtii

The time course of and the influence of light intensity and light quality on the induction of a mitochondrial carbonic anhydrase (CA) in the unicellular green alga Chlamydomonas reinhardtii was characterized using western and northern blots. This CA was expressed only under low-CO2 conditions (ambient air). In asynchronously grown cells, the mRNA was detected 15 min after transfer from air containing 5% CO2 to ambient air, and the 21-kD polypeptide was detected on western blots after 1 h. When transferred back to air containing 5% CO2, the mRNA disappeared within 1 h and the polypeptide was degraded within 3 d. Photosynthesis was required for the induction in asynchronous cultures. The induction increased with light up to 500 mumol m-2 s-1, where saturation occurred. In cells grown synchronously, however, expression of the mitochondrial CA was also detected in darkness. Under such conditions the expression followed a circadian rhythm, with mRNA appearing in the dark 30 min before the light was turned on. Algae left in darkness continued this rhythm for several days.

The Swedish Centenarian Study: a multidisciplinary study of five consecutive cohorts at the age of 100

Centenarians born 1887-91, who lived in southern Sweden were asked to participate in this multidisciplinary study (N = 164). Of the survivors (N = 143), 70 percent agreed (N = 100). The purpose was to describe the population from physical, social, and psychological points of view; to characterize centenarians with various health conditions and diverse degrees of autonomy and life satisfaction; and to identify factors at 100 years that predict future survival.

RESULTS

Eighty-two percent were women, 25 percent lived in their own home, 37 percent in old age homes, and 38 percent in nursing homes. Socioeconomic status showed a similar distribution compared to nationally representative data. Fifty-two percent managed activities of daily living with or without minor assistance. The incidence of severe diseases was low. In 39 percent a disorder of the circulatory system was found. Thirty-nine percent (women) and 11 percent (men) had had at least one hip fracture. Twenty percent had good hearing and good vision. Twenty-seven percent were demented according to DSM III-R criteria. Means on cognitive tests (word-list, digit-span, learning, and memory) were lower compared to seventy to eighty year old groups. The variation in performance was extremely widespread. Personality profiles (MMPI) indicated that the centenarians were more responsible, capable, easygoing and less prone to anxiety than the population in general. Extensive neuropathological investigation revealed no major diseases or large lesions but mild through multiple changes. RESULTS suggest that centenarians are a special group genetically. A causal structure model emphasized body constitution, marital status, cognition and blood pressure as particularly important determinants for survival after 100 years.

Carbon dioxide and light regulation of promoters controlling the expression of mitochondrial carbonic anhydrase in Chlamydomonas reinhardtii

Nuclear genes coding for carbonic anhydrase, a major mitochondrial constituent in Chlamydomonas reinhardtii grown under limited CO2, were characterized. Two genes, ca1 and ca2, were found within 7 kb of genomic DNA, organized 'head to head' in a large inverted repeat. The DNA sequences for the two genes were very similar, even in the promoter regions and in introns, indicating that the repeat is a result of a recent duplication. To study gene regulation, elements from the upstream region of ca1 were fused to the arylsulphatase reporter gene. After transformation, the expression of arylsulphatase was regulated similarly to the endogenous ca1/ca2 genes, even when the promoter was trimmed down to 194 nt. Expression could not be detected when 5% CO2 was bubbled into the growth medium, but was induced within hours after transfer to air. The ca1 promoter was not induced in low light, but at intermediate light levels its activity was dependent on the irradiance. O2 concentration had no effect on the promoter activity, indicating that photorespiratory metabolites are not triggering the response. The availability of cells transformed with a CO2-regulated reporter gene should facilitate further studies on the metabolic adaptations that occur in some green algae in response to the external CO2 level.

Molecular cloning and biochemical characterization of carbonic anhydrase from Populus tremula x tremuloides

A leaf cDNA library from hybrid aspen, Populus tremula x tremuloides, was constructed. From this two different cDNA clones, denoted CA1a and CA1b, encoding a chloroplastic carbonic anhydrase (CA) were isolated and DNA sequenced. Analysis of the deduced amino acid sequences showed that the isolated CAs belong to the beta-CA family, and have identities around 70% to other dicotyledonous plant CAs. The two hybrid aspen cDNA clones display a high nucleotide sequence identity, only 12 nucleotides differ. Since only one gene copy of this soluble chloroplastic CA is present in the nuclear genome, we postulate that the two isolated cDNA clones are alleles. Northern blot hybridization revealed a CA transcript of ca. 1300 bases, 140 bases shorter than in pea. Western and northern blot hybridizations on crude protein extracts and on total RNA, respectively, isolated from stem and leaves, showed that hybrid aspen CA is expressed specifically in the leaf under the growth conditions used. Based on the deduced amino acid sequence, the mature hybrid aspen CA enzyme subunit has a molecular mass of 24.8 kDa. The enzyme was over-expressed in Escherichia coli, and purified by affinity chromatography. Biochemical characterization showed that the protein structure and the CO2-hydration activity are similar to the pea enzyme. Molecular characterization of a CA from a perennial plant has not previously been performed, and it demonstrates that both the structure and activity of hybrid aspen CA resembles CAs from annual plants.

Blood pressure in relation to medical, psychological and social variables in a population of 80-year-olds. Survival during 6 years

OBJECTIVES

To relate elevated blood pressure in 80-year-olds to symptoms, life satisfaction and survival.

DESIGN

Examinations of medical, psychological and social factors every year between 80 and 86 years of age.

SETTING

Primary health care in the city of Lund in southern Sweden.

SUBJECTS

Three-hundred and thirty-three persons living in the city of Lund and born in 1908. Participation rate was 67%.

INTERVENTION

Abnormal findings were further examined and treated.

MAIN OUTCOME MEASURES

Symptoms, blood pressure, laboratory values, psychological factors, cognition, living conditions, and survival.

RESULTS

Hypertension according to the definition used was found in 70%. Women were over-represented (P < 0.05). Amongst persons with alleged hypertension, diuretics (P < 0.001) and 'other cardiovascular drugs' (P < 0.001) were more often used. Analgesics were more often used amongst assessed hypertensives (P < 0.05). Those with assessed hypertension scored better in testing of cognition compared to nonhypertensives (P < 0.05), and less often lived in institutions (P < 0.001). Assessed hypertensives had a better survival than alleged hypertensives during the following 7 years (P < 0.01).

CONCLUSIONS

Eighty-year-olds with assessed hypertension in the consulting room showed fewer symptoms and had a better cognition and survival than alleged hypertensives (those with a history of hypertension).

A cDNA coding for glutathione S-transferase from the unicellular green algae Coccomyxa sp

A cDNA coding for glutathione S-transferase (GST) was cloned and sequenced from the unicellular green algae Coccomyxa sp. The predicted 215 amino acid polypeptide (23.9 kDa, pI 5.3) is most similar to the theta-type GSTs found in a variety of different eukaryotic organisms. Within this sub-class, the Coccomyxa GST is 42% identical (63% similar) to the flatfish Pleuronectes platessa homologue, and 24 to 35% (49-57%) to other theta-type GST's.

Discovery of an algal mitochondrial carbonic anhydrase: molecular cloning and characterization of a low-CO2-induced polypeptide in Chlamydomonas reinhardtii

In green unicellular algae, several polypeptides are induced upon exposure to limiting CO2. We report here on the localization and characterization of one of these, a 22-kDa polypeptide in Chlamydomonas reinhardtii. This nuclear-encoded polypeptide is induced in the mitochondria by a lowering of the partial pressure of CO2 in the growth medium from 5% to air CO2 levels. Sequencing of two different cDNA clones coding for the polypeptide identified it as a 20.7-kDa beta-type carbonic anhydrase (CA; carbonate dehydratase, carbonate hydro-lyase, EC 4.2.1.1). The two clones differ in their nucleotide sequences but code for identical proteins, showing that this CA is encoded by at least two genes. Northern blot hybridization reveals that mRNA transcripts are only present in cells transferred to air CO2 levels. A comparison of the deduced amino acid sequence with those of other beta-CAs shows the largest degree of similarity with CA from the cyanobacterium Synechocystis (50% identity and 66% similarity). To our knowledge, this is the first identification and characterization of a mitochondrial CA from a photosynthetic organism.

Isolation of two new antiinflammatory biflavanoids from Sarcophyte piriei

Two new flavano flavanone glycosides, diinsininol (1) and diinsinin (2), have been isolated from the rhizome of Sarcophyte piriei, together with one known flavanone glycoside, naringenin 5-glucoside. Their structures were elucidated on spectroscopic evidence as 5,7,3',4'-tetrahydroxyflavanyl-7-O-beta-glucosyl-(4beta-8; 2beta-O-7)-eriodietyol (1) and 5,7,3',4'-tetrahydroxyflavanyl 7-O-beta-glucosyl-(4beta-8;2beta-O-7)-naringenin (2), respectively. The compounds were tested for their ability to inhibit prostaglandin synthesis, with 1 and 2 giving IC50 values of 9.20 microM and 13.14 microM, respectively, and in the inhibition of platelet-activating-factor-induced exocytosis, IC50 values of 49 and 39 microM.

Regulation of the supply of cytosolic oxaloacetate for mitochondrial metabolism via phosphoenolpyruvate carboxylase in barley leaf protoplasts. I. The effect of covalent modification on PEPC activity, pH response, and kinetic properties

The regulation of the supply of oxaloacetate (OAA) for mitochondrial metabolism via phosphoenolpyruvate carboxylase (PEPC) by covalent modification is studied in barley (Hordeum vulgare L.) leaf protoplasts in light or darkness as well as under photorespiratory or non-photorespiratory conditions. Extracts for studies on in vivo PEPC phosphorylation were prepared from barley leaf protoplasts by rapid filtration, fractionating the cell within less than 1 s. Measurements of in vitro PEPC activity were performed on samples quickly frozen in liquid nitrogen to break the cell and stop metabolism and thus preserve the in vivo activation state. The relative PEPC phosphorylation state increased upon illumination and decreased upon redarkening under photorespiratory and non-photorespiratory conditions. PEPC activity measured in the presence of malate (3 mM) under photorespiratory conditions showed the same response indicating that a light-induced increase in PEPC activity and decrease in malate sensitivity is caused by an increased phosphorylation level of the PEPC protein. PEPC activity was pH dependent. At the physiological cytosolic pH, activity was suboptimal, but most sensitive towards malate inhibition and glucose 6-phosphate stimulation. The presence of malate increased the sensitivity of PEPC activity towards pH changes. The response of PEPC activity to changing pH was not affected by changes in the activation state of the enzyme. The Km (phosphoenolpyruvate, PEP) is about 1 mM. Upon illumination the Km (PEP) decrease significantly. Vmax was unaffected by the light treatment. The presence of physiological concentrations of glucose 6-phosphate decreased Km (PEP) 5- to 10-fold and increased Vmax by about 35%. The effect of glucose 6-phosphate was strongest (up to 7-fold) at subsaturating PEP concentrations stimulating PEPC activity to nearly maximal rates. The results show that an increase in PEPC phosphorylation state causes an increase in PEPC activity as well as in substrate affinity leading to an increased production of OAA in the light.

Regulation of the supply of oxaloacetate for mitochondrial metabolism via phosphoenolpyruvate carboxylase in barley leaf protoplasts. II. Effects of metabolites on PEPC activity at different activation states of the protein

The regulation of the supply of oxaloacetate (OAA) for mitochondrial metabolism via phosphoenolpyruvate carboxylase (PEPC) by metabolites is studied in barley (Hordeum vulgare L.) leaf protoplasts in light or darkness as well as under photorespiratory or non-photorespiratory conditions. Measurements on PEPC activity were performed on samples quickly frozen in liquid nitrogen to break the cell and stop metabolism and thus preserve the in vivo activation state. Glycine, serine, pyruvate, acetyl-CoA, glycolate, fructose 1,6-bisphosphate, fructose 2,6-bisphosphate and ADP had no significant effect on PEPC activity. Malate, aspartate and glutamate were strong inhibitors of PEPC activity decreasing the activity more in light versus darkness. However, at the physiological cytosolic concentration of these metabolites under the respective conditions, inhibition of PEPC activity was about the same with the exception of aspartate which inhibits more under non-photorespiratory than under photorespiratory conditions. 2-Oxoglutarate and glyoxylate decreased PEPC activity by 20 to 40% in the range of its physiological cytosolic concentration. Inhibition by physiological cytosolic concentrations of glutamine was limited. Glucose 6-phosphate, fructose 6-phosphate, 3-phosphoglycerate, dihydroxyacetonphosphate and P(i) stimulated PEPC activity significantly in their physiological cytosolic concentration range. Physiological cytosolic concentrations of glucose 6-phosphate and fructose 6-phosphate activated PEPC activity to about the same extent under all conditions applied, while 3-phosphoglycerate and dihydroxyacetonphosphate stimulating stronger under non-photorespiratory versus photorespiratory conditions. Moreover, dihydroxyacetonphosphate stimulated PEPC activity more in light versus darkness under non-photorespiratory conditions. P(i) activation of PEPC activity decreases in light versus darkness under non-photorespiratory conditions. Stimulation of PEPC activity by citrate in its physiological concentration range is limited. Glucose 1-phosphate and AMP activated PEPC activity only at concentrations higher than their physiological levels in the cytosol. Determinations of PEPC activity in the presence of different malate/glucose 6-phosphate ratios revealed that glucose 6-phosphate totally relieved the inhibitory effect of malate. The regulatory properties of PEPC activity will be discussed in relation to its functions in C3 plants.

Laboratory values, symptoms and survival in an 80-year-old population

Medical, psychological and sociological factors were related to laboratory values in an 80-year-old population encompassing 211 persons. 21% of the men and 17% of the women had elevated ESR. 36% had elevated blood glucose (7% had diabetes). 13% of the men and 7% of the women had anaemia. Persons with anaemia generally had a lower quality of life compared with non-anaemic persons. Low haemoglobin, elevated ESR and low serum iron were all associated with impaired subjective and objective health. There were no significant correlations between the laboratory data and psychological and social parameters. The survival over 5 years was significantly decreased for those with anaemia, elevated ESR, high white blood count, high blood glucose, low serum iron or deviating serum potassium.

Intracellular carbonic anhydrase of Chlamydomonas reinhardtii

An intracellular carbonic anhydrase (CA; EC 4.2.1.1) was purified to homogeneity from a mutant strain of Chlamydomonas reinhardtii (CW 92) lacking a cell wall. Intact cells were washed to remove periplasmic CA and were lysed and fractionated into soluble and membrane fractions by sedimentation. All of the CA activity sedimented with the membrane fraction and was dissociated by treatment with a buffer containing 200 mM KCI. Solubilized proteins were fractionated by ammonium sulfate precipitation, anionic exchange chromatography, and hydrophobic interaction chromatography. The resulting fraction had a specific activity of 1260 Wilbur-Anderson units/mg protein and was inhibited by acetazolamide (50% inhibition concentration, 12 nM). Final purification was accomplished by the specific absorption of the enzyme to a Centricon-10 microconcentrator filter. A single, 29.5-kD polypeptide was eluted from the filter with sodium dodecyl sulfate-polyacrylamide gel electrophoresis sample buffer, and a 1.5 M ammonium sulfate eluate contained CA activity. In comparison with human CA isoenzyme II, the N-terminal and internal amino acid sequences from the 29.5-kD polypeptide were 40% identical with the N-terminal region and 67% identical with an internal conserved region. Based on this evidence, we postulate that the 29.5-kD polypeptide is an internal CA in C. reinhardtii and that the enzyme is closely related to the alpha-type CAs observed in animal species.

Apheresis technologies: an international perspective

The developments in apheresis techniques and their clinical applications world-wide are technologically driven. In the past, apheresis survey statistics have high-lighted both the differences by region in clinical practice and in the types of technologies utilized. Such differences have provided a basis for the scientific and clinical assessments of these apheresis technologies and their clinical outcomes and have stimulated the marketing and business development of new technologies world-wide. A review of the regional practices and technologies utilized provides a perspective on the future role of apheresis and its developments in clinical practice. While technology is a driving force for the development of new techniques for clinical practice, it is not the only market force. For technology introduction, several other important issues need to be considered. Regulations at the local and, most importantly, the federal level impact the timing for new technology introduction. Reimbursement by healthcare payers is critically important from the initiation of the development of a technology through its clinical use. Clinical trials are critically important to show the safety and clinical- and cost-effectiveness of the technology in order for payers to provide reimbursement for its use, but these trials are sometimes long and costly. Research funding availability at the governmental and commercial levels critically impacts new technology investigation and its introduction. Apheresis technology developments offer new hopes and promises for the clinical team; however, their development, introduction, and utilization will be influenced by the prevailing market forces.

Isolation, Purification, and Characterization of Mitochondria from Chlamydomonas reinhardtii

Mitochondria were isolated from autotrophically grown Chlamydomonas reinhardtii cell-wall-less mutant CW 92. The cells were broken by vortexing with glass beads, and the mitochondria were collected by differential centrifugation and purified on a Percoll gradient. The isolated mitochondria oxidized malate, pyruvate, succinate, NADH, and [alpha]-ketoglutarate. Respiratory control was obtained with malate (2.0) and pyruvate (2.2) but not with the other substrates. From experiments with KCN and salicylhydroxamic acid, it was estimated that the capacity of the cytochrome pathway was at least 100 nmol O2 mg-1 protein min-1 and the capacity of the alternative oxidase was at least 50 nmol O2 mg-1 protein min-1. A low sensitivity to oligomycin indicates some difference in the properties of the mitochondrial ATPase from Chlamydomonas as compared to higher plants.

Purification and characterisation of an intracellular carbonic anhydrase from the unicellular green alga Coccomyxa

An intracellular carbonic anhydrase (CA; EC 4.2.1.1) was purified and characterised from the unicellular green alga Coccomyxa sp. Initial studies showed that cultured Coccomyxa cells contain an intracellular CA activity around 100 times higher than that measured in high-CO2-grown cells of Chlamydomonas reinhardtii CW 92. Purification of a protein extract containing the CA activity was carried out using ammonium-sulphate precipitation followed by anion-exchange chromatography. Proteins were then separated by native (non-dissociating) polyacrylamide gel electrophoresis, with each individual protein band excised and assayed for CA activity. Measurements revealed CA activity associated with two discrete protein bands with similar molecular masses of 80 +/- 5 kDa. Dissociation by denaturing polyacrylamide gel electrophoresis showed that both proteins contained a single polypeptide of 26 kDa, suggesting that each 80-kDa native protein was a homogeneous trimer. Isoelectric focusing of the 80-kDa proteins also produced a single protein band at a pH of 6.5. Inhibition studies on the purified CA extract showed that 50% inhibition of CA activity was obtained using 1 microM azetazolamide. Polyclonal antibodies against the 26-kDa CA were produced and shown to have a high specific binding to a single polypeptide in soluble protein extracts from Coccomyxa cells. The same antiserum, however, failed to cross-react with soluble proteins isolated from two different species of green algae, Chlamydomonas reinhardtii and Chlorella vulgaris. Correspondingly, antisera directed against pea chloroplastic CA, extracellular CA from C. reinhardtii and human CAII, showed no cross-hybridisation to the 26-kDa polypeptide in Coccomyxa.(ABSTRACT TRUNCATED AT 250 WORDS)

Medical, psychological, and sociological aspects of drug treatment in 80-year-olds

The use of drugs was related to medical, psychological, and sociological parameters in an 80-year-old population. Use of drugs on the whole, as well as the use of specific drug categories such as digitalis, diuretics, other cardiovascular drugs, hypnotics, sedatives, analgesics and laxatives were related to an impaired quality of life. However, the use of vitamins and herbal pills was not related to an impaired quality of life. Use of hypnotics was related to neuroticism and to depressed mood. Persons using digitalis, diuretics and other cardiovascular drugs felt more lonely and had a stronger feeling of loneliness. According to a discriminant analysis, five questions could identify 70% of the persons using drugs. These questions were: frequency of visits to the doctor, subjective health, smoking (smokers used fewer drugs), feeling of loneliness, and objective health.

Medical, social and psychological factors as predictors of survival — a follow-up from 67 to 87 years of age

All pensioners in a primary care district (n=142) participating in a multi-disciplinary population study were followed from 67 years of age to the age of 87 with regard to survival. A multivariate survival analysis of psychological and social factors and medical symptoms at 67 years of age was used to test the relationship between such data and survival. Out of the 23 original medical, social and psychological factors/variables, the successive ranking risk factors for men were: positive attitudes to old-age homes, high social class, many reported disease at age 67, low degree of need satisfaction, and many reported earlier disease. For women the ranking of risk factors for early death were: early death age of mother, low degree of social rigidity, smoking, field-dependency and need of social help. The results reflect the interplay between hereditary, medical, social and psychological factors in predicting survival and how this interplay differs between males and females.

Family network and mortality: survival chances through the lifespan of an entire age cohort

This study relates certain family network variables (martial status and number of children) to chances of survival. Through multivariate analysis, survival is also related to social class, social mobility, migration and local environment, and legitimacy of birth. All persons in a local birth cohort born in the years 1902 and 1903 were followed in population records from birth until eighty years of age. The group comprised 487 individuals with a dropout rate of 4 percent. Univariate survival analysis between twenty to eighty years of age showed widows and also divorced women to have a significantly higher survival than those still married and never married. Never married men and women had the lowest survival rates. The number of children was not associated with survival for neither men nor women when controlled for marital status. Multiple regression survival analysis showed different patterns for males and females. The risk of not surviving to eighty years of age for men resulted from a combination of being single, downward social mobility, a father in the manual working class group and few children, with being single as the strongest predictor. For women the strongest predictor for death before eighty was the category single and/or married (as opposed to earlier married). The combination of being single/married, high migration, earlier life mainly in rural areas, and having few children were predictors in the model of death before eighty. Thus, for both men and women marital status was the strongest predictor for survival but in different ways.

Quality attributes of Swedish home-help services--from a consumer perspective

From existing Swedish literature, we examined different possible quality aspects of home-help services. We ordered the quality attributes of home help services under six headings: consumer adjustment of the services, competence of the staff and their attitudes, continuity, staff hours per services input, accessibility and information and communication. Concerning the relative importance of different quality aspects, our study indicates that the competence/attitudes of staff were clearly the most important quality factor. Within this category, individual qualities and attitudes were regarded as having greater importance than trained professional competence.

Inventory of plants used in traditional medicine in Somalia. IV. Plants of the families Passifloraceae-Zygophyllaceae

Thirty-seven plants are listed, which are used by traditional healers in the central and southern parts of Somalia. For each species are listed: the botanical name with synonyms, collection number, vernacular name, medicinal use, preparation of remedy and dosage. Results of a literature survey are also reported including medicinal use, substances isolated and pharmacological effects. Three plants which should have been included in Part I of the series have been added and some corrections to that paper have been made. With these additions the series comprises 180 different plant species, distributed in 59 plant families.

Microdontin A and B: Two New Aloin Derivatives from Aloe microdonta

The leaf juice of ALOE MICRODONTA Chiov. is used in Somali traditional medicine as a remedy for jaundice and for topical treatment of skin diseases. Mucilage was precipitated from the fresh juice by addition of ethanol and the supernatant chromatographed on Amberlite XAD-2 to yield a fraction containing anthraquinone derivatives. Flash chromatography on silica gel followed by preparative TLC yielded aloin A and a new compound. Spectral data (mass, (1)H- and (13)C-NMR) identified this compound as a mixture of aloin A and B where the glucose of both compounds is esterified with 4-hydroxycinnamic acid at the 6'-position. The two compounds were denoted as microdontin A and B, respectively.

Changes in Photosystem II fluorescence in Chlamydomonas reinhardtii exposed to increasing levels of irradiance in relationship to the photosynthetic response to light

The effects of a 60 min exposure to photosynthetic photon flux densities ranging from 300 to 2200 μmol m(-2)s(-1) on the photosynthetic light response curve and on PS II heterogeneity as reflected in chlorophyll a fluorescence were investigated using the unicellular green alga Chlamydomonas reinhardtii. It was established that exposure to high light acts at three different regulatory or inhibitory levels; 1) regulation occurs from 300 to 780 μmol m(-2)s(-1) where total amount of PS II centers and the shape of the light response curve is not significantly changed, 2) a first photoinhibitory range above 780 up to 1600 μmol m(-2)s(-1) where a progressive inhibition of the quantum yield and the rate of bending (convexity) of the light response curve can be related to the loss of QB-reducing centers and 3) a second photoinhibitory range above 1600 μmol m(-2)s(-1) where the rate of light saturated photosynthesis also decreases and convexity reaches zero. This was related to a particularly large decrease in PS IIα centers and a large increase in spill-over in energy to PS I.

Stability and change of personality in old age and its relation to survival

Stability of personality characteristics with increasing age was analyzed in a Swedish longitudinal study using a modified version of the Rod-and-Frame Test. This test was analyzed in a serial manner in order to emphasize cognitive style. Two important findings emerged. First, during the 6 years between the ages of 67 and 73, 80% of the study participants showed stability in the field independence-dependence dimension. Second, stability of the field independence-dependence trait between ages 67 and 73 predicted survival to age 83, whereas destabilization (i.e., changes of Rod-and-Frame Test classification) was significantly associated with earlier death. In most cases, destabilization meant that field-independent subjects became field dependent. The results are discussed in relation to dispositional and situational factors. Causative factors for destabilization are hypothesized.

[Dementia is not the only mental problem among the elderly. Long-term perspective is important for care]

The entire 1902 and 1903 birthyear cohorts in the catchment area of Dalby Community Health Centre in southern Sweden have been followed with health examinations and interviews every second year since 1969-70. Of the total of 192 subjects, complete data are available for 153. Of 65 subjects surviving at the age of 83, 6 per cent were advanced dementia cases, 11 per cent were in the early stages of dementia, and a further 17 per cent were afflicted with other mental problems requiring help and care. Of those who died before the age of 83, 11 per cent were afflicted with dementia, with a further 4 per cent in the early stages, and 17 per cent had other mental problems. Thus, the overall risk of dementia is at least 16 per cent, but may eventually turn out to be as high as 30 per cent, while those with other forms of mental dysfunction, serious enough to require help in ADL, account for a similar proportion. The annual incidence of dementia is 7.5 per mill (10.6 per mill including those in early stages). The risk of institutionalisation and death was much higher among the dementia victims, most of whom had had little support from the social services, and some none at all, before being institutionalised. Dementia victims came into contact with the medical services much earlier than did mentally healthy patients with other, often vague and more varied symptoms. It is argued in the article that current concern with dementia should not be allowed to divert our attention from the needs, diagnosis and care of the many elderly patients with other mental problems.

The effects of photoinhibition on the photosynthetic light-response curve of green plant cells (Chlamydomonas reinhardtii)

The photosynthetic response to light can be accurately defined in terms of (1) the initial slope (quantum yield); (2) the asymptote (light-saturated rate); (3) the convexity (rate of bending); and (4) the intercept (dark respiration). The effects of photoinhibition [which damages the reaction centre of photosystem II (PSII)] on these four parameters were measured in optically thin cultures of green plant cells (Chlamydomonas reinhardtii). The convexity of the light-response curve decreased steadily from a value of 0.98 (indicating a sharply bending response) to zero (indicating Michaelis-Menten kinetics) in response to increasing photoinhibition. Photoinhibition was quantified from the quantum yield of inhibited cells relative to that of control cells. The quantum yield was estimated by applying linear regression to low-light data or by fitting a non-rectangular hyperbola. Assuming the initial slope is linear allowed comparison with earlier work. However, as the convexity was lowered this assumption resulted in a significant underestimate of the true quantum yield. Thus, the apparent level of photoinhibition required for a zero convexity and the initial decrease in light-saturated photosynthesis depended upon how the quantum yield was estimated. If the initial slope of the light response was assumed to be linear the critical level of inhibition was 60%. If the linear assumption was not made, the critical level was 40%. At the level of inhibition where the convexity reached zero, the light-saturated rate of photosynthesis also began to decrease, indicating that this level of inhibition caused photosynthesis to be limited at all light intensities by the rate of PSII electron transport. At this level of inhibition the Fm-Fi signal (where Fm is maximal chlorophyll fluorescence and Fi is intermediate chlorophyll fluorescence of dark adapted cells; Briantais et al. 1988) from the fluorescence induction curve was zero and the Fi-Fo signal (where Fo is initial chlorophyll fluorescence of dark adapted cells) was 30% of the control, indicating dramatic reduction or complete elimination of one type of PSII. These data do not contradict published mathematical models showing that the ratio of the maximum speed of electron transport in PSII relative to the maximum speed of plastoquinone electron transport can determine the convexity of the photosynthetic response to light.

Acclimation of Photosynthetic Light Reactions during Induction of Inorganic Carbon Accumulation in the Green Alga Chlamydomonas reinhardtii

Cells of the unicellular green algae Chlamydomonas reinhardtii were grown in high dissolved inorganic carbon (DIC) concentrations (supplied with 50 milliliters per liter CO(2)[g]) and transferred to low DIC concentrations (supplied with </= 100 microliters per liter CO(2)[g]). Immediately after transfer from high to low DIC the emission of photosystem II related chlorophyll a fluorescence was substantially quenched. It is hypothesized that the suddenly induced inorganic carbon limitation of photosynthesis resulted in a phosphorylation of LHCII, leading to the subsequent state 1 to state 2 transition. After 2 hours of low-DIC acclimation, 77 K fluorescence measurements revealed an increase in the fluorescence emitted from photosystem I, due to direct excitation, suggesting a change in photosystem II/photosystem I stoichiometry or an increased light harvesting capacity of photosystem I. After 5 to 6 hours of acclimation a considerable increase in spillover from photosystem II to photosystem I was observed. These adjustments of the photosynthetic light reactions reached steady-state after about 12 hours of low DIC treatment. The quencher of fluorescence could be removed by 5 minutes of dark treatment followed by 5 minutes of weak light treatment, of any of four different light qualities. It is hypothesized that this restoration of fluorescence was due to a state 2 to state 1 transition in low-DIC acclimated cells. A decreased ratio of violaxanthin to zeaxanthin was also observed in 12 hour low DIC treated cells, compared with high DIC grown cells. This ratio was not coupled to the level of fluorescence quenching. The role of different processes during the induction of a DIC accumulating mechanism is discussed.