Abscisic acid signal transduction in guard cells is mediated by phospholipase D activity

In guard cells, the plant hormone abscisic acid (ABA) inhibits stomatal opening and induces stomatal closure through the coordinated regulation of ion transport. Despite this central role of ABA in regulating stomatal function, the signal transduction events leading to altered ion fluxes remain incompletely understood. We report that the activity of the enzyme phospholipase D (PLD) transiently increased in guard cell protoplasts at 2.5 and 25 min after ABA application. Treatment of guard cell protoplasts with phosphatidic acid (PtdOH), one of the products of PLD activity, led to an inhibition of the activity of the inward K+ channel. PtdOH also induced stomatal closure and inhibited stomatal opening when added to epidermal peels. Application of 1-butanol (1-buOH), a selective inhibitor of PtdOH production by PLD, inhibited the increase in PtdOH production elicited by ABA. 1-BuOH treatment also partially prevented ABA-induced stomatal closure and ABA-induced inhibition of stomatal opening. This inhibitory effect of buOH was enhanced by simultaneous application of nicotinamide, an inhibitor of cADP ribose action. These results suggest that in the guard cell, ABA activates the enzyme PLD, which leads to the production of PtdOH. This PtdOH is then involved in triggering subsequent ABA responses of the cell via a pathway operating in parallel to cADP ribose-mediated events.

Age of the earliest known hominids in Java, Indonesia

40Ar/39Ar laser-incremental heating of hornblende separated from pumice recovered at two hominid sites in Java, Indonesia, has yielded well-defined plateaus with weighted mean ages of 1.81 +/- 0.04 and 1.66 +/- 0.04 million years ago (Ma). The hominid fossils, a juvenile calvaria of Pithecanthropus and a partial face and cranial fragments of Meganthropus, commonly considered part of the Asian Homo erectus hypodigm, are at least 0.6 million years older than fossils referred to as Homo erectus (OH-9) from Olduvai Gorge, Tanzania, and comparable in age with the oldest Koobi Fora Homo cf. erectus (Homo ergaster) in Kenya. These ages lend further credence to the view that Homo erectus may have evolved outside of Africa. If the ancestor of Homo erectus ventured out of Africa before 1.8 Ma, the dispersal would have predated the advent of the Acheulean culture at 1.4 Ma, possibly explaining the absence of these characteristic stone cleavers and hand axes in East Asia.

A twin study of genetic and environmental influences on suicidality in men

BACKGROUND

Previous studies that have examined genetic influences on suicidal behaviour were confounded by genetic vulnerability for psychiatric risk factors. The present study examines genetic influences on suicidality (i.e. suicidal ideation and/or suicide attempt) after controlling for the inheritance of psychiatric disorders.

METHODS

Sociodemographics, combat exposure, lifetime DSM-III-R major depression, bipolar disorder, childhood conduct disorder, adult antisocial personality disorder, panic disorder, post-traumatic stress disorder, drug dependence, alcohol dependence and lifetime suicidal ideation and attempt were assessed in 3372 twin pairs from the Vietnam Era Twin Registry who were assessed in 1987 and 1992. Genetic risk factors for suicidality were examined in a multinomial logistic regression model. Additive genetic, shared environmental and non-shared environmental effects on suicidality were estimated using structural equation modelling, controlling for other risk factors.

RESULTS

The prevalence of suicidal ideation and suicide attempt were 16.1% and 2.4% respectively. In a multinomial regression model, co-twin's suicidality, being white, unemployment, being other than married, medium combat exposure and psychiatric disorders were significant predictors for suicidal ideation. Co-twin's suicidality, unemployment, marital disruption, low education attainment and psychiatric disorders (except childhood conduct disorder) were significant predictors for suicide attempt. Model-fitting suggested that suicidal ideation was influenced by additive genetic (36%) and non-shared environmental (64%) effects, while suicide attempt was affected by additive genetic (17%), shared environmental (19%) and non-shared environmental (64%) effects.

CONCLUSIONS

There may be a genetic susceptibility specific to both suicidal ideation and suicide attempt in men, which is not explained by the inheritance of common psychiatric disorders.

Tamoxifen blocks chloride channels. A possible mechanism for cataract formation

Tamoxifen is an antiestrogen frequently used in the treatment of breast cancer and is currently being assessed as a prophylactic for those at high risk of developing tumors. We have found that tamoxifen and its derivatives are high-affinity blockers of specific chloride channels. This blockade appears to be independent of the interaction of tamoxifen with the estrogen receptor and therefore reflects an alternative cellular target. One of the clinical side effects of tamoxifen is impaired vision and cataract. Chloride channels in the lens of the eye were shown to be essential for maintaining normal lens hydration and transmittance. These channels were blocked by tamoxifen and, in organ culture, tamoxifen led to lens opacity associated with cataracts at clinically relevant concentrations. These data suggest a molecular mechanism by which tamoxifen can cause cataract formation and have implications for the clinical use of tamoxifen and related antiestrogens.

Localized changes in apoplastic and cytoplasmic pH are associated with root hair development in Arabidopsis thaliana

Morphogenesis in plants is characterized by highly regulated cell enlargement. However, the mechanisms controlling and localizing regions of growth remain essentially unknown. Root hair formation involves the induction of a localized cell expansion in the lateral wall of a root epidermal cell. This expanded region then enters a second phase of localized growth called tip growth. Root hair formation therefore provides a model in which to study the cellular events involved in regulating localized growth in plants. Confocal ratio imaging of the pH of the cell wall revealed an acidification at the root hair initiation site. This acidification was present from the first morphological indications of localized growth, but not before, and was maintained to the point where the process of root hair initiation ceased and tip growth began. Preventing the wall acidification with pH buffers arrested the initiation process but growth resumed when the wall was returned to an acidic pH. Cytoplasmic pH was found to be elevated from approximately 7.3 to 7. 7 at the initiation site, and this elevation coincided with the acidification of the wall. Preventing the localized increase in cytoplasmic pH with 10 mM butyrate however did not inhibit either the wall acidification or the initiation process. In contrast, there was no detectable gradient in pH associated with the apex of tip growing root hairs, but both elevated apoplastic pH and butyrate treatment irreversibly inhibited the tip growth process. Thus the processes of tip growth and initiation of root hairs show differences in their pH requirements. These results highlight the role of localized control of apoplastic pH in the control of cell architecture and morphogenesis in plants.

Low back pain: reliability of a set of pain measurement tools

OBJECTIVES

To determine the reliability and internal consistency of a set of low back pain (LBP)-related measurement tools and to determine whether they are appropriate for use in a large-scale, community-based sample in Israel.

DESIGN

Test-retest reliability study, with an interval of 2 to 14 days between test and retest.

SETTING

Physiotherapy clinics.

PARTICIPANTS

One hundred fifty-one patients with LBP.

MAIN OUTCOME MEASURES

The Modified Roland-Morris Disability Questionnaire (MRMQ); a simple verbal pain severity scale; and modified pain symptoms frequency and bothersomeness indices. Three measures of variables with potential association with LBP were also used: a Fear-Avoidance Beliefs Questionnaire (FABQ), work satisfaction scale, and the Baecke Physical Activity Questionnaire (BPAQ).

RESULTS

Test-retest reliability was high for the MRMQ, pain symptom indices, work index of the FABQ, and occupational activity index of the BPAQ; the internal consistency of the MRMQ and FABQ work index were also high (intraclass correlation coefficient >or= .89; alpha = .89).

CONCLUSIONS

Most measurement tools are reliable and suitable for community LBP studies in Israel.

Influences of marital conflict on child adjustment: review of theory and research

This review summarizes the literature on the relationship between marital conflict and child maladjustment with an emphasis on variables that qualify, explain the association, or both. Following a historical review, the modest findings on the strength of the association between marital conflict and child maladjustment is explored. The definition of marital conflict is clarified through specification of its various dimensions (frequency, intensity, content, resolution). The role of variables that serve to moderate and/or mediate the relationship between marital conflict and child maladjustment are elaborated. Mediating models include exposure theories (Modeling, Cognitive-Contextual effects: appraisal of threat and blame, and Emotional Insecurity) and changes in the parent-child relationship (Spillover). Variables that moderate or qualify the relationship include children's cognitions and behaviors, contextual factors, and demographic differences. A model is presented summarizing these mechanisms. Research recommendations are proposed and the clinical implications of this literature are addressed.

Early brain growth in Homo erectus and implications for cognitive ability

Humans differ from other primates in their significantly lengthened growth period. The persistence of a fetal pattern of brain growth after birth is another important feature of human development. Here we present the results of an analysis of the 1.8-million-year-old Mojokerto child (Perning 1, Java), the only well preserved skull of a Homo erectus infant, by computed tomography. Comparison with a large series of extant humans and chimpanzees indicates that this individual was about 1 yr (0-1.5 yr) old at death and had an endocranial capacity at 72-84% of an average adult H. erectus. This pattern of relative brain growth resembles that of living apes, but differs from that seen in extant humans. It implies that major differences in the development of cognitive capabilities existed between H. erectus and anatomically modern humans.

The role of ClC-3 in volume-activated chloride currents and volume regulation in bovine epithelial cells demonstrated by antisense inhibition

1. A chloride current with mild outward rectification was induced in the native bovine non-pigmented ciliary epithelial (NPCE) cells by a 23 % hypotonic solution. The current showed no or little inactivation at depolarized steps. 2. ATP blocked 88 and 61 % of the outward and inward components of the volume-activated chloride current (ICl,vol) with an IC50 of 5.3 and 9.6 mM, respectively. 3. The volume-activated chloride current was decreased and the activation of the current was delayed by inhibiting endogenous ClC-3 expression using a ClC-3 antisense oligonucleotide. The inhibition of the current as a function of antisense concentration was asymptotic with a maximum about 60 %. The remaining current was probably not derived from ClC-3 and was inhibited by ATP. 4. ClC-3 expression in the bovine NPCE cells was verified by immunofluorescence studies. ClC-3 immunofluorescence was distributed throughout the cells but with the predominant location within the nucleus. The expression of ClC-3 protein was diminished by the ClC-3 antisense oligonucleotide with the greatest diminution occurring in the nuclear region. 5. The size of the volume-activated chloride current was positively correlated with the ClC-3 immunofluorescence level. 6. Regulatory volume decrease of the NPCE cells was reduced by ClC-3 antisense oligonucleotide. 7. We conclude that endogenous ClC-3 is associated with the volume-activated chloride current and is involved in cell volume regulation, but that it can only contribute towards a proportion of the current in NPCE cells. 8. The nuclear predominance of ClC-3 immunofluorescence in NPCE cells, the absence of basal activity of chloride current and the marked pharmacological differences between IClC-3 and ICl,vol argue against ClC-3 being the only, or even the main, volume-activated chloride channel in NPCE cells.

Evidence for peripheral plasticity in human odour response

Of those people who are anosmic to androstenone, a proportion can acquire sensitivity to it by repeated exposure and even those who are able to smell it can lower their threshold with this treatment. Using olfactory threshold testing, intranasal electrophysiology and EEG we show for the first time that: (1) the subjects' detection threshold is proportional to the amplitude of the olfactory evoked potential (EOG) recorded inside the nose; (2) the EOG amplitude is correlated with the amplitude of the olfactory event-related potential (OERP) recorded on the scalp; and (3) with repetitive exposure, human subjects acquire a reduced threshold for androstenone and, as they do so, their EOG and OERP increase. These observations support the existence of odourant-specific plasticity in the peripheral olfactory system.

The Sambungmacan 3 Homo erectus calvaria: a comparative morphometric and morphological analysis

The Sambungmacan (Sm) 3 calvaria, discovered on Java in 1977, was illegally removed from Indonesia in 1998 and appeared in New York City in early 1999 at the Maxilla & Mandible, Ltd. natural history shop. Here we undertake an analysis of its phylogenetic and systematic position using geometric morphometrics and comparative morphology. The coordinates of points in the sagittal plane from glabella to opisthion were resampled to yield "lines" of 50 semi-landmarks. Coordinates of glabella, bregma, lambda, inion, and opisthion were also collected and analyzed separately. Casts of Homo erectus fossils from Indonesia, China, and Kenya and of "archaic H. sapiens" from Kabwe and Petralona, as well as 10 modern human crania, were used as the primary comparative sample. The modern humans were well separated from the fossils in a graphical superimposition of Procrustes-aligned semi-landmarks as well as in principal component and canonical discriminant analyses. In all of these, Sm 3 falls intermediate between the fossil and modern groups. Morphological comparisons of Sm 3 with a selection of Homo erectus fossils revealed its greatest similarity to specimens from Ngandong and the Sm 1 calvaria. Compared to all other H. erectus, Sm 3 was distinctive in its more vertical supratoral plane, less anteriorly projecting glabella and less sharply angled occiput. In these features it was somewhat similar to modern humans. It is not yet possible to determine if this similarity implies an evolutionary relationship or (more likely) individual or local populational variation. Several features of Sm 3 (small size, gracile supraorbital torus and lack of angular torus, and position in principal component analysis) suggest that it was a female. The use of geometric morphometrics provides a means to statistically test the shapes of such fossils in a manner not easily duplicated by other methods. The intermediate position of Sm 3 between fossil and modern samples in several different subanalyses exemplifies the value of this approach.

Marital interactions of depressed men and women

This article examined marital interactions in 50 couples with a depressed husband, 41 couples with a depressed wife, and 50 nondepressed control couples. As expected, couples with a depressed partner evidenced more disturbed marital interaction than control couples. Furthermore, couples with a depressed wife demonstrated less positive communication than couples with a depressed husband, notwithstanding the fact the depressed husbands exhibited greater depression severity than depressed wives. Findings are integrated with recent research on gender differences in affective expression.

P-glycoprotein regulates a volume-activated chloride current in bovine non-pigmented ciliary epithelial cells

1. The whole-cell patch clamp technique was used to investigate the swelling-activated currents in bovine non-pigmented ciliary epithelial (NPCE) cells. 2. Exposure to hypotonic solution activated a current that was blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB). The I-V relationship was shifted in the direction expected for a Cl- current when the external Cl- was replaced by gluconate (permeability ratio P(gluconate)/PCl = 0.17). The inhibition of the current evoked by voltage clamp steps of +80 mV yielded an IC50 for NPPB of 13.4 microM. 3. The current was found to be dependent on ATP. With ATP in the patch pipette the current could be repeatedly activated by exposure to hypotonic solution but when ATP was omitted the current ran down with time. 4. The development of this current was associated with visible cell swelling and inhibitors of regulatory volume decrease in these cells, e.g. tamoxifen, 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonic acid (SITS) and 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS), also inhibited this current. 5. The volume-activated current was additionally blocked by NPPB, verapamil, quinidine and dideoxyforskolin. 6. The current was independent of external calcium and exhibited slight outward rectification and time-dependent inactivation at strong depolarizing potentials. 7. Disrupting the cytoskeleton and microtubules with cytochalasin B and colchicine had no effect on the activation of the Cl- current. 8. An antibody (C219) to the MDR1 gene product, P-glycoprotein, caused a functional block of the swelling-activated Cl- current when added to the patch pipette. 9. Immunofluorescence studies using the monoclonal antibodies C219 and JSB-1 demonstrated the presence of P-glycoprotein in the ciliary epithelial cells. The immunofluorescence was stronger on the non-pigmented than on the pigmented cells. 10. It is concluded that swelling in NPCE cells activates a Ca(2+)-independent, ATP-dependent Cl- current and that the activity of this current is associated with P-glycoprotein. 11. It is suggested that this Cl- current contributes to regulatory volume decrease and may participate in the secretory activity of these cells.

ATP-activated chloride channel inhibited by an antibody to P glycoprotein

In this report, we present the characteristics of a Cl- channel found in lens fiber cells. The single channel has a conductance of 17 pS, a linear current-voltage curve, is activated by ATP or strong depolarization and is blocked by verapamil, quinidine, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, 5-nitro-2-(3- phenylpropylamino)benzoate, dideoxyforskolin, and tamoxifen. These properties are similar to those reported for a volume-activated Cl- channel associated with the multidrug resistance (MDR) gene product, P glycoprotein (24). Confirming this connection, we demonstrate that our lens Cl- channel is inhibited by an antibody to P glycoprotein. The data we present here may, therefore, be the first characterization of the single channel activity of the Cl- channel associated with P glycoprotein.

Psychosocial functioning in children of alcoholic fathers, depressed fathers and control fathers

Children of alcoholics are often viewed as having major psychological problems resulting from their interactions within disturbed family structures. Most studies, however, have selected alcoholics from multiproblem families in which it is difficult to disentangle the impact of alcoholism from concomitant psychosocial and psychiatric problems. Further, few studies have used psychometrically sound measures of alcoholism or child functioning. In this investigation, children of alcoholic, depressed and control (social drinkers and not depressed) fathers were assessed by parents on the Child Behavior Checklist and by teachers on the Conner Teacher Rating Scale and the Myklebust Pupil Rating Scale. Although children of alcoholics and of depressives were rated higher on behavior problems by parents than the children of controls, only a minority of these children received scores indicative of severe impairment. The importance of considering the clinical significance of group differences and of examining the joint impact of alcoholism and other psychopathologies is discussed.

Role of ion channels in aqueous humor formation

The aqueous humor is secreted by the ciliary epithelium, a bilayered syncytial epithelium comprising a pigmented (PE) cell layer abutting the stroma and a nonpigmented (NPE) cell layer facing the aqueous phase. As in other epithelia, secretion depends on the transfer of solute, with water passively following. Na+, K+, and Cl- enter the syncytium principally through a Na(+)-K(+)-2Cl- symport, diffusing to the aqueous surface of the NPE cells. The Na+, K+, and Cl- are secreted into the aqueous humor through the Na+/K+ exchange pump, K+ channels, and Cl- channels, respectively. Na+ is also secreted between the cells in response to a small transepithelial potential. The K+ channels are critical not only for K+ release but also for hyperpolarizing the membrane, providing an electrical driving force for Cl- secretion. Some of the K+ channels are Ca2+ sensitive and can be activated by Ca2+ entry through T- and L-type Ca2+ channels. The roles of the ciliary epithelial nonselective and Na+ channels are less clear. This review describes the ion channels thus far identified in the ciliary epithelium in terms of the activation and inactivation of their macroscopic currents, the open probabilities and conductances of the single channels, and their locations and regulation. The review relates each class of channel to known families of channels and indicates how those channels can contribute to the secretion of the aqueous humor.

The alcoholic's spouse, children and family interactions. Substantive findings and methodological issues

Literature on the personality characteristics of spouses of alcoholics, on the psychosocial status of children of alcoholics and on alcoholic-spouse and alcoholic--family interactions is reviewed.

Association of intrinsic pICln with volume-activated Cl- current and volume regulation in a native epithelial cell

We investigated the relationship between pICln, the volume-activated Cl- current, and volume regulation in native bovine nonpigmented ciliary epithelial (NPCE) cells. Immunofluorescence studies demonstrated the presence of pICln protein in the NPCE cells. Exposure to hypotonic solution activated a Cl- current and induced regulatory volume decrease (RVD) in freshly isolated bovine NPCE cells. Three antisense oligonucleotides complementary to human pICln mRNA were used in the experiments. The antisense oligonucleotides were taken up by the cells in a dose-dependent manner. The antisense oligonucleotides, designed to be complementary to the initiation codon region of the human pICln mRNA, "knocked down" the pICln protein immunofluorescence, delayed the activation of volume-activated Cl- current, diminished the value of the current, and reduced the ability of the cells to volume regulate. We conclude that pICln is involved in the activation pathway of the volume-activated Cl- current and RVD following hypotonic swelling.

Sequential interactions in the marital communication of depressed men and women

Despite studies showing patterns of sequential interaction between depressed wives and their husbands, no published research has contrasted sequential interactions of depressed husbands and their wives. This study compared problem-solving interactions of 49 couples with a depressed husband, 41 with a depressed wife, and 50 normal controls. Interactions were coded using the Marital Interaction Coding System. Although no clear patterns of sequential interaction distinguished couples with a depressed wife from normal control couples, results suggested a unique pattern of interaction between depressed husbands and their spouses, whereby positive communications from the husband resulted in decreased positivity and increased negativity from their wives. Given the importance of positivity for promoting effective problem solving, this pattern appears to have important implications for couples' long-term marital satisfaction and husbands' mood regulation.

A comparison of marital interaction patterns between couples in which the husband does or does not have Alzheimer's disease

Objectives. Our main purpose was to examine similarities and differences in patterns of interpersonal interaction between Alzheimer's disease (AD) caregiving and noncaregiving couples (n = 54). Methods. Twenty-seven wives caring for moderately impaired husbands with probable AD and 27 noncaregiving wives from comparable sociodemographic backgrounds were videotaped in their homes during both mealtime and a future event planning task. In addition, they completed self-report questionnaires to assess depression, stress, relationship mutuality, and perceived hope. Results. Compared with their counterparts, caregiving wives reported higher levels of depression and stress, but similar shared values and closeness. For the three factors developed from the Marital Interaction Coding System (MICS, version IV; Supportive Facilitative, and Rapport Building), a complex pattern of results was found in which disease status, type of task, and gender interacted significantly. Noncaregiving couples were more interactive overall and expressed more support to each other. Caregiving wives were found to be most facilitative during the planning task, whereas AD husbands were highest on interactions that built rapport (e.g., smiling) during that same task. Caregiving wives actually increased their facilitative behavior from the mealtime to planning task, probably reflecting the increased demand characteristics of the latter.

DISCUSSION

This study is one of a small body of literature to describe the negative impact of AD on spousal communication as observed and coded in two videotaped interaction situations in the home. Suggestions are made for future research, including the inclusion of longitudinal designs and non-Caucasian couples.

Volume-sensitive chloride current in pigmented ciliary epithelial cells: role of phospholipases

The whole cell recording technique was used to examine an outwardly rectifying chloride current activated by hypotonic shock in bovine pigmented ciliary epithelial (PCE) cells. Removal of internal and external Ca2+ did not affect the activation of these currents, but they were abolished by the phospholipase C inhibitor neomycin. The current was blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid, and 4,4'-disothiocyanostilbene-2,2'-disulfonic acid (DIDS) in a voltage-dependent manner, but tamoxifen, dideoxyforskolin, and quinidine did not affect it. This blocking profile differs from that of the volume-sensitive chloride channel in neighboring nonpigmented ciliary epithelial cells (Wu, J., J. J. Zhang, H. Koppel, and T. J. C. Jacob, J. Physiol, Lond. 491: 743-755, 1996), and this difference implies that the volume responses of the two cell types are mediated by different chloride channels (Jacob, T. J. C., and J. J. Zhang. J. Physiol. Lond. In press). Intracellular administration of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) to PCE cells induced a transient, time-independent, outwardly rectifying chloride current that closely resembled the current activated by hypotonic shock. DIDS produced a voltage-dependent block of the GTP gamma S-activated current similar to the block of the hypotonically activated current. Intracellular neomycin completely prevented activation of this current as did incubation of the cells in calphostin C. and inhibitor of protein kinase C (PKC). Removal of Ca2+ did not affect activation of the current by GTP gamma S but extended the duration of the response. Inhibition of phospholipase A2 (PLA2) with p-bromophenacyl bromide prevented the activation of the hypotonically induced current and also inhibited the current once activated by hypotonic solution. The findings imply that the hypotonic response in PCE cells is mediated by both phospholipase C (PLC) and PLA2. Both phospholipases generate arachidonic acid, and, in addition, the PLC pathway regulates the PLA2 pathway via a PKC-dependent phosphorylation of PLA2.

Negative family environment as a predictor of boys' future status on measures of hostile attitudes, interview behavior, and anger expression

The present study tested the hypothesis that family environments characterized as nonsupportive, unaccepting, and conflictual lead to the development of hostile traits in adolescent Caucasian boys. Negative behaviors during parent-son discussions aimed at resolving disagreements were observed in a laboratory setting in 51 intact families. Sons' hostile traits were assessed at the time of the interactions and then 3 years later. Results showed that a high frequency of negative behaviors exhibited by both parents and sons predicted sons' later hostile attitudes and outward expression of anger after adjustment for their initial level of hostile attitudes and anger expression, respectively. A low frequency of positive behaviors exhibited by the father and son predicted sons' later Potential for Hostility ratings after adjustment for their initial level. The meaning of these findings for the conceptualization of hostility is discussed.