Aberrant chloroplasts in transgenic rice plants expressing a high level of maize NADP-dependent malic enzyme

 NADP-dependent malic enzyme (NADP-ME) is a major decarboxylating enzyme in NADP-ME-type C₄ species such as maize and Flaveria. In this study, chloroplastic NADP-ME was transferred to rice (Oryza sativa L.) using a chimeric gene composed of maize NADP-ME cDNA under the control of rice light-harvesting chlorophyll-a/b-binding protein (Cab) promoter. There was a 20- to 70-fold increase in the NADP-ME activity in leaves of transgenic rice compared to that in wild-type rice plants. Immunocytochemical studies by electron microscopy showed that maize NADP-ME was mostly localized in chloroplasts in transgenic rice plants, and that the chloroplasts were agranal without thylakoid stacking. Chlorophyll content and photosystem II activity were inversely correlated with the level of NADP-ME activity. These results suggest that aberrant chloroplasts in transgenic plants may be caused by excessive NADP-ME activity. Based on these results and the known fact that only bundle sheath cells of NADP-ME species, among all three C₄ subgroups, have agranal chloroplasts, we postulate that a high level of chloroplastic NADP-ME activity could strongly affect the development of chloroplasts. Received: 27 January 1999 / Accepted: 20 January 2000     

Over-expression of a tobacco homeobox gene, NTH15 , decreases the expression of a gibberellin biosynthetic gene encoding GA 20-oxidase

Ectopic expression of the homeobox gene, NTH15 ( Nicotiana tabacum homeobox 15) in transgenic tobacco leads to abnormal leaf and flower morphology, accompanied by a decrease in the content of the active gibberellin, GA₁. Quantitative analysis of intermediates in the GA biosynthetic pathway revealed that the step from GA₁₉ to GA₂₀ was blocked in transgenic tobacco plants overexpressing NTH15 . To investigate the relationship between the expression of NTH15 and genes involved in GA biosynthesis, we isolated three cDNA clones from tobacco encoding two types of GA 20-oxidase and a 3β-hydroxylase. RNA gel blot analysis revealed that the expression of one gene ( Ntc12 , encoding GA 20-oxidase), which in wild-type tobacco plants was abundantly expressed in leaves, was strongly suppressed in the transformants. The expression level of Ntc12 decreased with increasing severity of phenotype of transgenic tobacco leaves. The abnormal leaf morphology was largely overcome by treatment with GA₂₀ or GA₁ but not by GA₁₉. These data strongly suggest that overexpression of NTH15 inhibits the expression of Ntc12 , resulting in reduced levels of active GA and abnormal leaf morphology in transgenic tobacco plants. In situ hybridization in wild-type tobacco revealed that expression of Ntc12 occurred mainly in the rib meristem, cells surrounding the procambium and in leaf primordia. Expression was not seen in the tunica, corpus and procambium, tissues in which NTH15 was predominantly expressed. The contrasting expression patterns of these genes may reflect their antagonistic functions in the formation of lateral organs from the shoot apical meristem.     

Aggregation as a cost-reducing strategy for lycaenid larvae

If a mutualistic relationship entails providing services ata cost, selection will favor individuals that maximize the netbenefits of the interaction and minimize the costs. Larvae ofmany species of lycaenid butterflies secrete nutritious foodrewards to attending ants and, in return, receive protectionagainst predators and parasitoids. Because ants typically recruitmore workers to larger resources, by forming groups the larvaemay ensure more reliable access to ants and thereby gain betterprotection. A further consequence of aggregating should be achange of the cost-benefit relationship for individual larvae.The larger the group, the smaller a single larva's influencewill be on total ant density, which could lead to a smallerinvestment in secretion, thus reducing the per capita cost ofcooperation. In this study, die influence of ant attendance,group size, and companion quality on larval investment was investigated.The interaction between the obligately ant-dependent lycaenid,Jalmanus evagoras, and its attendant Iridomyrmax ants was manipulatedand the effect on larval secretion measured. As the level ofant attendance increased, the delivery of food rewards increased,bodi for solitary and for aggregated larvae. When aggregated,larvae provided less food rewards to ants dun when solitary,and secretion rate decreased with increasing group size. Furthermore,larvae had lower secretion rates when paired with a bigger,more attractive larva than when paired with a smaller one. Theconsiderable reduction in secretion rates for larvae in groupssuggests that gaining protection at a lower secretion cost couldbe one factor that promotes aggregation in myrmecophilous lycaenids.     

RESOLVING EVOLUTIONARY RELATIONSHIPS AMONG THE BROWN ALGAE USING CHLOROPLAST AND NUCLEAR GENES1

The brown algae are one of the largest and most important groups of primary producers in benthic coastal marine environments. Despite their biological importance, consensus regarding their taxonomic or evolutionary relationships remains elusive. Our goal was to produce a taxon‐rich two‐gene (rbcL and LSU rDNA) phylogeny. Key species were sequenced to represent each order and family in the analyses across all 19 orders and ～40 families, including selected outgroups Schizocladiophyceae and Xanthophyceae. Our results are in sharp contrast to traditional phylogenetic concepts; the Ectocarpales are not an early diverging clade, nor do the Fucales diverge early from other brown algae. Rather, Choristocarpus is sister to the remaining brown algae. Other groups traditionally considered to have primitive features are actually recently diverged lineages, turning traditional phylogenetic concepts upside down. Additionally, our results allow for the assessment, in the broadest context, of many of the historical and more recent taxonomic changes, resulting in several emended groups along with proposals for two new orders (Onslowiales, Nemodermatales) and one new family (Phaeosiphoniellaceae).     

AUDIT,AUDIT-C,and AUDIT-3: Drinking Patterns and Screening for Harmful,Hazardous and Dependent Drinking in Katutura,Namibia

Objectives

To describe alcohol drinking patterns among participants in Katutura, Namibia, and to evaluate brief versions of the AUDIT against the full AUDIT to determine their effectiveness in detecting harmful drinking.

Methods

A cross-sectional survey was conducted in four constituencies and 639 participants, 18 years or older, completed a sociodemographic survey and the AUDIT. The effectiveness of the AUDIT-C (first three questions) and the AUDIT-3 (third question) was compared to the full AUDIT.

Results

Approximately 40% were identified as harmful, hazardous or likely dependent drinkers, with men having a higher likelihood than women (57.2% vs. 31.0%, p<.0001). Approximately 32% reported making and/or selling alcohol from home. The AUDIT-C performed best at a cutoff ≥ 3, better in men (sensitivity: 99.3%, specificity: 77.8%) than women (sensitivity: 91.7%, specificity: 77.4%). The AUDIT-3 performed poorly (maximum sensitivity: < 90%, maximum specificity: <51%). According to AUROC, the AUDIT-C performed better than the AUDIT-3.

Conclusions

A large proportion of participants met criteria for alcohol misuse, indicating a need for screening and referral for further evaluation and intervention. The AUDIT-C was almost as effective as the full AUDIT and may be easier to implement in clinical settings as a routine screening tool in resource-limited settings because of its brevity.     

Factors that Influence the Way Communities Respond to Proposals for Major Changes to Local Emergency Services: A Qualitative Study

Objective

According to policy commentators, decisions about how best to organise care involve trade-offs between factors relating to care quality, workforce, cost, and patient access. In England, proposed changes such as Emergency Department closures often face public opposition. This study examined the way communities respond to plans aimed at reorganising emergency services, including the trade-offs inherent in such decisions.

Design

Cross-sectional study involving in-depth interviews. Participants selected their priorities for emergency care, including aspects they might be prepared to have ‘less’ of (e.g. rapid access) if it meant having ‘more’ of another (e.g. consultant-delivered care). A thematic analysis was carried out, combining inductive and deductive approaches, drawing on theories about risk perception.

Setting

Two urban areas of England; one where changes to emergency services were under consideration (‘Greenville’), and one where they were not (‘Hilltown’).

Participants

28 participants in total. Greenville interviewees included more common emergency service users - parents of young children (n=5) and older people (n=6) - plus patient representatives and individuals campaigning against service closures (n=9). Hilltown interviewees (n=8) received outpatient care for Chronic Obstructive Pulmonary Disease, an important cause of emergency admission.

Results

Most participants, in both areas, were not willing to accommodate the trade-offs involved in consolidating emergency services, principally because of the belief that timely access is associated with better outcomes. Participants did not consider the proposed improvements as gains worth having; interviewees believed care quality would be adversely impact, partly because increased patient numbers would place staff under greater pressure and result in longer waiting times.

Conclusions

Visible clinical leadership and detailed explanation of the case for change were insufficient to overcome opposition to the reconfiguration in Greenville, challenging the assumption that communities can be persuaded by evidence. Commissioners should make explicit credible plans to accommodate changes in patient flows, as well as clarifying the roles played by key staff groups.     

Arabinogalactan biosynthesis: Implication of AtGALT29A enzyme activity regulated by phosphorylation and co-localized enzymes for nucleotide sugar metabolism in the compartments outside of the Golgi apparatus

Arabinogalactan proteins are abundant cell surface proteoglycans in plants and are implicated to act as developmental markers during plant growth. We previously reported that AtGALT31A, AtGALT29A, and AtGLCAT14A-C, which are involved in the biosynthesis of arabinogalactan proteins, localize not only to the Golgi cisternae but also to smaller compartments, which may be a part of the unconventional protein secretory pathway in plants. In Poulsen et al.,¹ we have demonstrated increased targeting of AtGALT29A to small compartments when Y144 is substituted with another amino acid, and we implicated a role for Y144 in the subcellular targeting of AtGALT29A. In this paper, we are presenting another aspect of Y144 substitution in AtGALT29A; namely, Y144A construct demonstrated a 2.5-fold increase while Y144E construct demonstrated a 2-fold decrease in the galactosyltransferase activity of AtGALT29A. Therefore, the electrostatic status of Y144, which is regulated by an unknown kinase/phosphatase system, may regulate AtGALT29A enzyme activity. Moreover, we have identified additional proteins, apyrase 3 (APY3; At1g14240) and UDP-glucuronate epimerases 1 and 6 (GAE1, At4g30440; GAE6, At3g23820), from Arabidopsis thaliana that co-localize with AtGALT31A in the small compartments when expressed transiently in Nicotiana benthamiana. These proteins may play roles in nucleotide sugar metabolism in the small compartments together with arabinogalactan glycosyltransferases.     

Cost Evaluation of Reproductive and Primary Health Care Mobile Service Delivery for Women in Two Rural Districts in South Africa

Background

Cervical cancer screening is a critical health service that is often unavailable to women in under-resourced settings. In order to expand access to this and other reproductive and primary health care services, a South African non-governmental organization established a van-based mobile clinic in two rural districts in South Africa. To inform policy and budgeting, we conducted a cost evaluation of this service delivery model.

Methods

The evaluation was retrospective (October 2012–September 2013 for one district and April–September 2013 for the second district) and conducted from a provider cost perspective. Services evaluated included cervical cancer screening, HIV counselling and testing, syndromic management of sexually transmitted infections (STIs), breast exams, provision of condoms, contraceptives, and general health education. Fixed costs, including vehicle purchase and conversion, equipment, operating costs and mobile clinic staffing, were collected from program records and public sector pricing information. The number of women accessing different services was multiplied by ingredients-based variable costs, reflecting the consumables required. All costs are reported in 2013 USD.

Results

Fixed costs accounted for most of the total annual costs of the mobile clinics (85% and 94% for the two districts); the largest contributor to annual fixed costs was staff salaries. Average costs per patient were driven by the total number of patients seen, at $46.09 and $76.03 for the two districts. Variable costs for Pap smears were higher than for other services provided, and some services, such as breast exams and STI and tuberculosis symptoms screening, had no marginal cost.

Conclusions

Staffing costs are the largest component of providing mobile health services to rural communities. Yet, in remote areas where patient volumes do not exceed nursing staff capacity, incorporating multiple services within a cervical cancer screening program is an approach to potentially expand access to health care without added costs.