WHO method for estimating congenital syphilis to inform surveillance and service provision, Paraguay.

Problem: In Paraguay, incomplete surveillance data resulted in the burden of congenital syphilis being underestimated, which, in turn, led to missed opportunities for infant diagnosis and treatment. Approach: The prevalence of congenital syphilis, as defined by the World Health Organization (WHO), was estimated for Paraguay using the WHO congenital syphilis estimation tool. This tool was also used to monitor progress towards the elimination of mother-to-child transmission of syphilis. Local setting: The burden of syphilis in Paraguay has historically been high: its prevalence in pregnant women was estimated to be 3% in 2018. Relevant changes: The incidence rate of congenital syphilis estimated using the WHO tool was around nine times the reported prevalence. Subsequently, Paraguay: (i) provided training to improve diagnosis and case reporting; (ii) strengthened information systems for case monitoring and reporting; and (iii) procured additional rapid dual HIV-syphilis and rapid plasma reagin tests to increase syphilis testing capacity. In addition, the Ministry of Health prepared a new national plan for eliminating mother-to-child transmission of syphilis, with clear monitoring milestones. Lessons learnt: Health-care providers' reporting and surveillance procedures for congenital syphilis may not adequately reflect national and international case definitions. Use of the WHO congenital syphilis estimation tool in Paraguay drew attention to congenital syphilis as a national public health problem and highlighted the importance of comprehensive national surveillance systems and accurate data. Ongoing use of the WHO tool can track progress towards the elimination of mother-to-child transmission of syphilis by helping improve syphilis service coverage and national surveillance.

Progress towards achieving viral hepatitis B and C elimination in the Asia and Pacific region: Results from modelling and global reporting.

In 2016, Asia and Pacific countries endorsed action plans for reaching viral hepatitis elimination targets set in the Global Health Sector Strategy (GHSS) for Viral Hepatitis 2016-2021. We examine the region's progress by modelling disease burden and constructing the cascade of care. Between 2015 and 2020, chronic HBV prevalence declined from 4.69% to 4.30%, and HCV prevalence declined from 0.64% to 0.58%. The region achieved the 2020 target of 30% incidence reduction for HBV, whereas HCV incidence declined by 6%. Hepatocellular carcinoma incidence for HBV and HCV increased by 9% and 7%, respectively. Liver-related deaths from HBV rose by 8%, and mortality attributable to HCV plateaued. Large testing and treatment gaps remained in 2019: only 13% of chronic HBV infections were diagnosed and 25% treated; 21% of chronic HCV infection were diagnosed and 11% treated. Viral hepatitis must become national priority with adequate funding to reach elimination goals by 2030.

Effectiveness and Tolerability of Oral Amoxicillin in Pregnant Women with Active Syphilis, Japan, 2010-2018.

We conducted a nationwide retrospective study in Japan to evaluate the effectiveness of oral amoxicillin or ampicillin as alternatives to injectable benzathine penicillin G for treating pregnant women with syphilis and preventing congenital syphilis (CS). We investigated 80 pregnant women with active syphilis treated with amoxicillin or ampicillin during 2010-2018. Overall, 21% (15/71) had pregnancies resulting in CS cases, and 3.8% (3/80) changed therapies because of side effects. Among 26 patients with early syphilis, no CS cases occurred, but among 45 with late syphilis, 15 (33%) CS cases occurred. Among 57 patients who started treatment >60 days before delivery, 8 (14%) had CS pregnancy outcomes. We found oral amoxicillin potentially ineffective for preventing CS cases among pregnant women with late syphilis but potentially effective in those with early syphilis. Prospective studies are needed to definitively evaluate the efficacy of amoxicillin for the treatment of pregnant women with syphilis to prevent CS.

Genetic consequences of being a dwarf: do evolutionary changes in life-history traits influence gene flow patterns in populations of the world's smallest goldenrod?

BACKGROUND AND AIMS: Contrasting life-history traits can evolve through generations of dwarf plant ecotypes, yet such phenotypic changes often involve decreased plant size and reproductive allocation, which can configure seed dispersal patterns and, subsequently, population demography. Therefore, evolutionary transitions to dwarfism can represent good study systems to test the roles of life-history traits in population demography by comparing genetic structure between related but phenotypically divergent ecotypes. METHODS: In this study, we examined an ecotypic taxon pair of the world's smallest goldenrod (stem height 2.6 cm) in alpine habitats and its closely related lowland taxon (30-40 cm) found on Yakushima Island, Japan. Genetic variation in chloroplast DNA sequences, nuclear microsatellites and genome-wide single-nucleotide polymorphisms were used to investigate 197 samples from 16 populations, to infer the population genetic demography and compare local genetic structure of the ecotypes. KEY RESULTS: We found a pronounced level of genetic differentiation among alpine dwarf populations, which were much less geographically isolated than their lowland counterparts. In particular, several neighbouring dwarf populations (located ~500 m apart) harboured completely different sets of chloroplast haplotypes and nuclear genetic clusters. Demographic modelling revealed that the dwarf populations have not exchanged genes at significant levels after population divergence. CONCLUSIONS: These lines of evidence suggest that substantial effects of genetic drift have operated on these dwarf populations. The low-growing stature and reduced fecundity (only 3.1 heads per plant) of the dwarf plants may have reduced gene flow and rare long-distance seed dispersal among habitat patches, although the effects of life-history traits require further evaluation using ecological approaches.

Progress Toward Hepatitis B Control and Elimination of Mother-to-Child Transmission of Hepatitis B Virus - Western Pacific Region, 2005-2017.

Hepatitis B vaccine (HepB), which has been available since 1982, provides lifelong protection against hepatitis B virus (HBV) infection and the associated 20%-30% increased lifetime risk for developing cirrhosis or hepatocellular carcinoma among >95% of vaccine recipients (1). Before HepB introduction into national childhood immunization schedules, the estimated hepatitis B surface antigen (HBsAg) prevalence in the World Health Organization (WHO) Western Pacific Region (WPR)* was >8% in 1990 (2). In 2005, the WPR was the first WHO region to establish a hepatitis B control goal, with an initial target of reducing HBsAg prevalence to <2% among children aged 5 years by 2012. In 2013, the WPR set more stringent control targets to achieve by 2017, including reducing HBsAg prevalence to <1% in children aged 5 years and increasing national coverage with both timely HepB birth dose (HepB-BD) (defined as administration within 24 hours of birth) and the third HepB dose (HepB3) to ≥95% (3). All WPR countries/areas endorsed the Regional Action Plan for Viral Hepatitis in the Western Pacific Region 2016-2020 in 2015 (4) and the Regional Framework for the Triple Elimination of Mother-to-Child Transmission of human immunodeficiency virus (HIV), Hepatitis B and Syphilis in Asia and the Pacific 2018-2030 (triple elimination framework) in 2017 (5). These regional targets and strategies are aligned with program targets established by the WHO Global Health Sector Strategy on Viral Hepatitis 2016-2021 that aim to reduce HBsAg prevalence among children aged 5 years to ≤1% by 2020 and to ≤0.1% by 2030 (6). This report describes progress made to achieve hepatitis B control in the WPR and the steps taken to eliminate mother-to-child transmission (MTCT) of HBV during 2005-2017. During this period, regional timely HepB-BD and HepB3 coverage increased from 63% to 85% and from 76% to 93%, respectively. As of December 2017, 15 (42%) countries/areas achieved ≥95% timely HepB-BD coverage; 18 (50%) reached ≥95% HepB3 coverage; and 19 (53%) countries/areas as well as the region as a whole were verified to have achieved the regional and global target of <1% HBsAg prevalence among children aged 5 years. Continued implementation of proven vaccination strategies will be needed to make further progress toward WPR hepatitis B control targets. In addition to high HepB-BD and HepB3 coverage, enhanced implementation of complementary hepatitis B prevention services through the triple elimination framework, including routine HBsAg testing of pregnant women, timely administration of hepatitis B immunoglobulin to exposed newborns, and antiviral treatment of mothers with high viral loads, will be needed to achieve the global hepatitis B elimination target by 2030.

Phylogeographic analysis of the East Asian goldenrod (Solidago virgaurea complex, Asteraceae) reveals hidden ecological diversification with recurrent formation of ecotypes.

Background and Aims: The processes and mechanisms underlying lineage diversification are major topics in evolutionary biology. Eurasian goldenrod species of the Solidago virgaurea complex show remarkable morphological and ecological diversity in the Japanese Archipelago, with ecotypic taxa well adapted to specific environments (climate, edaphic conditions and disturbance regimes). The species complex is a suitable model to investigate the evolutionary processes of actively speciating plant groups, due to its ability to evolve in relation to environmental adaptation and its historical population dynamics. Methods: Two chloroplast markers, 18 nuclear microsatellite markers and ddRAD-sequencing were used to infer population genetic demography of S. virgaurea complex with its related species/genera. Key Results: Our analysis showed that populations in Japan form an evolutionary unit, which was genetically diverged from adjacent continental populations. The phylogenetic structure within the archipelago strongly corresponds to the geography, but interestingly there is no concordance between genetic structure and ecotypic boundaries; neighbouring populations of distinct ecotypes share a genetic background. Conclusions: We propose that the traits specific to the ecotypic entities are maintained by natural selection or are very recently generated and have little effect on the genomes, making genome-wide genetic markers unsuitable for detecting ecotypic differentiation. Furthermore, some sporadically distributed taxa (found as rheophytes and alpine plants) were repeatedly generated from a more widespread taxon in geographically distant areas by means of selection. Overall, this study showed that the goldenrod complex has a high ability to evolve, enabling rapid ecological diversification over a recent timeframe.

Psychological well-being and adherence to antiretroviral therapy among adolescents living with HIV in Zambia.

Physical and psychosocial changes during adolescence could influence the psychological well-being and adherence to antiretroviral therapy (ART) of adolescents living with HIV. However, few studies have assessed these two important issues in Zambia. This study aimed at addressing this gap by examining adolescents' depressive symptoms and ART adherence. This was a mixed-methods study conducted from April to July 2014. We recruited 200 adolescents, ages 15 to 19, who were already aware of their HIV status. We measured depressive symptoms using the short form of the Center for Epidemiologic Studies Depression Scale, and self-reported three-day adherence to ART. We performed logistic regression analysis to identify factors associated with depressive symptoms and non-adherence to ART. For qualitative data, we examined challenges over ART adherence using thematic analysis. Out of 190 adolescents, 25.3% showed high scores of depressive symptoms. Factors associated with depressive symptoms were unsatisfactory relationships with family (Adjusted Odds Ratio [AOR] 3.01; 95% Confidence Interval [CI] 1.20-7.56); unsatisfactory relationships with health workers (AOR 2.68; 95% CI 1.04-6.93); and experience of stigma (AOR 2.99; 95% CI 1.07-8.41). Of all participants, 94.2% were taking ART, but 28.3% were non-adherent. Factors associated with non-adherence to ART were loss of a mother (AOR 3.00; 95% CI 1.05-8.58) and lack of basic knowledge about HIV (AOR 3.25; 95% CI 1.43-7.40). Qualitative data identified the following challenges to ART adherence: management of medication, physical reactions to medicine, and psychosocial distress. The evidence suggests that depressive symptoms and non-adherence to ART were priority issues in late adolescence in Zambia. Health workers should be aware of these issues, and the care and treatment services should be tailored to respond to age-specific needs.

Disclosure to HIV-seropositive children in rural Zambia.

BACKGROUND: Care of children living with HIV comprises various issues, some considered challenging. One of the challenging areas is the serostatus disclosure to HIV-positive children. This study describes the current situation of HIV disclosure among rural children in Zambia and examines the socio-demographic factors promoting disclosure. METHODS: We used a mixed method approach applying both quantitative and qualitative methods to obtain comprehensive picture of HIV serostatus disclosure for children. Data were collected in Mumbwa district, Zambia (2010-2012), included 57 clinical records of children older than 5 years old. We examined children's age, gender, and cohabitation status with their parents, caregivers' level of education and income, and the relation between children and caregivers. Logistic regression model was applied to examine associations between disclosure and socio-demographic characteristics. Semi-structured interviews with 50 caregivers and 22 HIV-positive children were conducted to qualitatively investigate attitude towards disclosure and support needed. RESULTS: Full disclosure was completed in 17 out of 57 (29.8%) patients. Median ages of patients in disclosed group and non-disclosed group were 10 and 9, respectively (IQR 8.0-13.0, 7.0-11.25). In univariate analyses, older age and male gender has positive relation to the completion of serostatus disclosure. In logistic regression models, cohabitation status with patients' mothers showed positive correlation to the completion of serostatus disclosure. In the interviews with caregivers, all caregivers said that disclosure of serostatus is a necessary process and good for their children, while actual serostatus disclosure rate was low. CONCLUSION: Serostatus disclosure to HIV-seropositive children is not prevalent in Rural Zambia. Although further researches would be desirable, increased support to caregivers would be beneficial.

Sexual and reproductive health behavior and unmet needs among a sample of adolescents living with HIV in Zambia: a cross-sectional study.

BACKGROUND: Adolescents living with HIV face challenges, such as disclosure of HIV status, adherence to antiretroviral therapy, mental health, and sexual and reproductive health (SRH). These challenges affect their future quality of life. However, little evidence is available on their sexual behaviors and SRH needs in Zambia. This study aimed at assessing their sexual behaviors and SRH needs and identifying factors associated with marriage concerns and a desire to have children. METHODS: This cross-sectional study was conducted at the University Teaching Hospital from April to July 2014. We recruited 200 adolescents aged 15-19 years who were aware of their HIV-positive status. We collected data on their first and recent sexual behavior, concerns about marriage, and desire to have children. We used the Generalized Linear Model to identify factors associated with having concerns about marriage and desire to have children. We performed thematic analysis with open-ended data to determine their perceptions about marriage and having children in the future. RESULTS: Out of 175 studied adolescents, 20.6% had experienced sexual intercourse, and only 44.4% used condoms during the first intercourse. Forty-eight percent had concerns about marriage, and 87.4% desired to have children. Marriage-related concerns were high among those who desired to have children (adjusted relative risk [ARR] = 2.51, 95% CI = 1.02 to 6.14). Adolescents who had completed secondary school were more likely to desire to have children (ARR = 1.35, 95% CI = 1.07 to 1.71). Adolescents who had lost both parents were less likely to want children (ARR = 0.80, 95% CI = 0.68 to 0.95). Thematic analysis identified that major concerns about future marriage were fear of disclosing HIV status to partners and risk of infecting partners and/or children. The reasons for their willingness to have children were the desire to be a parent, having children as family assets, a human right, and a source of love and happiness. CONCLUSIONS: Zambian adolescents living with HIV are at risk of engaging in risky sexual relationships and have difficulties in meeting needs of SRH. HIV care service must respond to a wide range of needs.

Elimination of mother-to-child transmission of HIV and Syphilis (EMTCT): Process, progress, and program integration.

Melanie Taylor and colleagues discuss progress towards eliminating vertical transmission of HIV and syphilis.

Simultaneous evaluation of the effects of geographic, environmental and temporal isolation in ecotypic populations of Solidago virgaurea.

Early stages of ecological speciation can create populations with an ecology and reproduction timing distinct from those of related populations. Landscape genetic models incorporating environmental heterogeneity and population-specific reproductive traits enable the processes of population genetic differentiation to be inferred. We investigated genome-wide genetic variation in ecotypic populations of Solidago virgaurea sensu lato, a herbaceous plant inhabiting a wide range of habitats (woodlands, serpentine barrens and alpine grasslands) and displaying remarkable variation in flowering time. Simultaneous evaluation of environmental factors revealed an overwhelming effect of soil type differences on neutral genetic differentiation, compared with elevational differences. This result probably reflects the abrupt environmental changes generated by geological boundaries, whereas mountain slopes exhibit clinal changes, facilitating gene exchange between neighbouring populations. Temporal isolation was positively associated with genetic differentiation, with some early-flowering serpentine populations having allele frequencies distinct from adjacent nonserpentine populations. Overall, this study highlights the importance of ecological processes and of evolution of flowering time to promote genetic differentiation of S. virgaurea populations in a complex landscape.

Molecular bases for phyllomorph development in a one-leaf plant, Monophyllaea glabra.

PREMISE OF THE STUDY: The aboveground part of one-leaf plants (Gesneriaceae) consists of a unique shoot-like unit called a phyllomorph, which is composed of a growing lamina and one petiolode (a stem- and petiole-like organ). The phyllomorph has three meristems: a basal meristem (BM; involved in lamina growth), a petiolode meristem (PM; required for midrib and petiolode growth), and a groove meristem (GM; contributes to inflorescence and new phyllomorph development). Although the GM has a tunica-corpus structure like a conventional shoot apical meristem (SAM), the vegetative GM of a one-leaf plant does not form any organ primordia and has been considered a defective or suppressed SAM. In this study, we evaluated the nature of the three meristems to reconsider their roles in phyllomorph development in the one-leaf species Monophyllaea glabra. METHODS: Mitotic activities of meristem cells were monitored by incorporation of a thymidine analog (EdU) into DNA. Orthologs of SHOOTMERISTEMLESS (STM) and PHANTASTICA, ROUGH SHEATH2, ASYMMETRIC LEAVES1 (PHAN/RS2/AS1) were isolated from M. glabra, and their expression patterns were investigated by quantitative reverse transcription polymerase chain reaction in combination with a laser microdissection technique. KEY RESULTS: Mitotic activities were detected in all three phyllomorph meristems. Strong expression of the STM and PHAN/RS2/AS1 orthologs was detected in the vegetative GM and BM, respectively. CONCLUSIONS: The vegetative GM is an active meristem that expresses the STM ortholog. We postulate that the GM is required for growth of a phyllomorph by providing undifferentiated cells and/or growth regulators to the BM and/or PM.

[Treatment for self-injurious behavior in mentally handicapped populations--a report from our practice].

OBJECTIVE: Self-injurious behavior (SIB) is a common problem in individuals with intellectual disabilities, yet its clinical management remains to be established. We aimed to clarify the background factors and profiles of SIB in mentally and physically handicapped subjects and subsequently examined the efficacy of treatments attempted in our practice in order to achieve a better understanding of SIB and appro- priate interventions in these populations. METHODS: We surveyed 92 mentally handicapped subjects with SIB (including 25 females and 67 males, most of whom also had physical disabilities) as outpatients or inpatients of our institution using a retrospective questionnaire com- pleted by the corresponding doctors. RESULTS: Regarding psychobehavioral complications, impulsive mood swings (such as sudden rage) were more frequent than other behaviors. As to probable triggers of SIB, the patient's physical condition (17 cases) and noise or the temperature of the surrounding environment (38 cases) were identified. A total of 81 of 92 patients were given a prescription for SIB. Risperidone was the most commonly prescribed drug (75 cases), found to be effective in 38 (50.6%) cases, whereas phenothiazine antipsychotics were often more effective in patients with profound SIB. SSRIs (selective serotonin reuptake inhibitors) were applied in 20 cases, being effective in only five (25%) patients and discontinued in 11 (55%) patients due to the onset of several side effects, including overexcitement. As an additional agent for mood control, the antiepileptic topiramate was effective in 10 (76.9%) of 13 cases. Aside from medication, equipment for elbow extension was beneficial in some of the patients with profound SIB. CONCLUSIONS: Pharmacological intervention is sometimes beneficial, albeit only partly. Clinicians must therefore also consider triggers and factors in the surrounding environment for the development of SIB in mentally handicapped individuals.

Longitudinal adherence to antiretroviral drugs for preventing mother-to-child transmission of HIV in Zambia.

BACKGROUND: Adherence to antiretroviral (ARV) drugs is essential for eliminating new pediatric infections of human immunodeficiency virus (HIV). Since the Zambian government revised the national guidelines based on option A (i.e., maternal zidovudine and infant ARV prophylaxis) of the World Health Organization's 2010 guidelines, no studies have assessed adherence to ARVs during pregnancy up to the postpartum period. This study aimed to examine adherence to ARVs and identify the associated risk factors. METHODS: A prospective cohort study was conducted in the Chongwe district from June 2011 to January 2014. Self-reported adherence to ARVs was examined during pregnancy and at one week, six weeks, and 24 weeks postpartum among 321 HIV-positive women. The probability of remaining adherent to ARVs was estimated using the Kaplan-Meier method, and the risk factors for non-adherence were identified using the Cox proportional hazard regressions--treating loss to follow-up as non-adherence. The statuses of HIV in HIV-exposed infants were assessed in January 2014. RESULTS: During the study period, 326 infants were born to HIV-positive women, 262 (80.4%) underwent HIV testing, and 11 (3.4%) had their HIV infection detected at the time that they had the latest HIV testing as of January 2014. The ARV adherence rate was 82.5% during pregnancy, 84.2% at one week postpartum, 81.5% at six weeks postpartum, and 70.5% at 24 weeks postpartum. The probability of remaining adherent to ARVs was 0.61 at day 50, 0.35 at day 100, 0.18 at day 200, and 0.06 at day 300. Attending a referral health center (HC) was a risk factor for non-adherence compared with attending rural HCs that provided HIV care/treatment (adjusted hazard ratio [aHR] 0.71, 95% confidence interval [CI] 0.57-0.88) and those that did not provide HIV care/treatment (aHR 0.58, 95% CI 0.46-0.74). A new diagnosis of HIV infection compared to a known HIV-positive status before pregnancy was another risk factor for non-adherence (aHR 1.24, 95% CI 1.03-1.50). CONCLUSIONS: Maintaining adherence to ARVs through pregnancy to the postpartum period remains a crucial challenge in Zambia. To maximize the treatment benefits, adherence to ARVs and retention in care should be improved at all health facilities.

Arundina graminifolia var. revoluta (Arethuseae, Orchidaceae) has fern-type rheophyte characteristics in the leaves.

Morphological and molecular variation between Arundina graminifolia var. graminifolia and the dwarf variety, A. graminifolia var. revoluta, was examined to assess the validity of their taxonomic characteristics and genetic background for identification. Morphological analysis in combination with field observations indicated that A. graminifolia var. revoluta is a rheophyte form of A. graminifolia characterized by narrow leaves, whereas the other morphological characteristics described for A. graminifolia var. revoluta, such as smaller flowers and short stems, were not always accompanied by the narrower leaf phenotype. Molecular analysis based on matK sequences indicated that only partial differentiation has occurred between A. graminifolia var. graminifolia and A. graminifolia var. revoluta. Therefore, we should consider the rheophyte form an ecotype rather than a variety. Anatomical observations of the leaves revealed that the rheophyte form of A. graminifolia possessed characteristics of the rheophytes of both ferns and angiosperms, such as narrower palisade tissue cells and thinner spongy tissue cells, as well as fewer cells in the leaf-width direction and fewer mesophyll cell layers.

Comparative analysis of the RTFL peptide family on the control of plant organogenesis.

Plant peptides play important roles in various aspects of plant growth and development. The RTFL/DVL family includes small peptides that are widely conserved among land plants. Overexpression of six RTFL genes in Arabidopsis was suggestive of their functions as negative regulators of cell proliferation and as positional cues along the longitudinal axis of the plant body . At this time, few reports are available on RTFL paralogs in other species and the evolutionary relationship of RTFL members among land plants remains unclear. In this study, we compared and analyzed whole amino acid sequences of 188 RTFL members from 22 species among land plants and identified 73 motifs. All RTFL members could be grouped into four clades, and each clade exhibited specific motif patterns, indicative of unique evolutionary traits in the RTFL family. In agreement with this hypothesis, we analyzed two RTFL members from Oryza sativa and Arabidopsis by overexpressing them in Arabidopsis, revealing similar phenotypes suggestive of a conserved function of the RTFL family between eudicots and monocots, as well as different phenotypes and unique functions.

Bond formation and coupling between germyl and bridging germylene ligands in dinuclear palladium(I) complexes.

The dinuclear palladium(I) complexes [L(Ar2 HGe)Pd(µ-GeAr2 )2 Pd(GeHAr2 )L] (Ar=Ph, p-Tol; L=PMe3 , tBuNC) contain terminal germyl and bridging germylene ligands with the experimentally observed Ge⋅⋅⋅Ge bond lengths of 2.8263(4) Š(L=PMe3 ) and 2.928(1) Š(L=tBuNC), which are close to the longest Ge-Ge bond reported to date [2.714(1) Å]. Significant Ge⋅⋅⋅Ge interactions between the germylene and germyl ligands (PMe3 complexes > tBuNC complexes) are supported by DFT calculations, Wiberg bond indices (WBI), and natural bond orbital (NBO) analyses. Exchanging tBuNC for PMe3 ligands increases the Ge⋅⋅⋅Ge interaction, and simultaneously activates two Pd-Ge bonds. Adding the chelating diphosphine 1,2-bis(diethylphosphino)ethane (depe) to the PMe3 complexes results in the intramolecular coupling of germyl and germylene ligands followed by extrusion of a digermane.

Nitrogen dioxide regulates organ growth by controlling cell proliferation and enlargement in Arabidopsis.

• To gain more insight into the physiological function of nitrogen dioxide (NO2), we investigated the effects of exogenous NO2 on growth in Arabidopsis thaliana. • Plants were grown in air without NO2 for 1 wk after sowing and then grown for 1-4 wk in air with (designated treated plants) or without (control plants) NO2. Plants were irrigated semiweekly with a nutrient solution containing 19.7 mM nitrate and 10.3 mM ammonium. • Five-week-old plants treated with 50 ppb NO2 showed a ≤ 2.8-fold increase in biomass relative to controls. Treated plants also showed early flowering. The magnitude of the effects of NO2 on leaf expansion, cell proliferation and enlargement was greater in developing than in maturing leaves. Leaf areas were 1.3-8.4 times larger on treated plants than corresponding leaves on control plants. The NO2-induced increase in leaf size was largely attributable to cell proliferation in developing leaves, but was attributable to both cell proliferation and enlargement in maturing leaves. The expression of different sets of genes for cell proliferation and/or enlargement was induced by NO2, but depended on the leaf developmental stage. • Collectively, these results indicated that NO2 regulates organ growth by controlling cell proliferation and enlargement.

The ATM-dependent DNA damage response acts as an upstream trigger for compensation in the fas1 mutation during Arabidopsis leaf development.

During leaf development, a decrease in cell number often triggers an increase in cell size. This phenomenon, called compensation, suggests that some system coordinates cell proliferation and cell expansion, but how this is mediated at the molecular level is still unclear. The fugu2 mutants in Arabidopsis (Arabidopsis thaliana) exhibit typical compensation phenotypes. Here, we report that the FUGU2 gene encodes FASCIATA1 (FAS1), the p150 subunit of Chromatin Assembly Factor1. To uncover how the fas1 mutation induces compensation, we performed microarray analyses and found that many genes involved in the DNA damage response are up-regulated in fas1. Our genetic analysis further showed that activation of the DNA damage response and the accompanying decrease of cell number in fas1 depend on ATAXIA TELANGIECTASIA MUTATED (ATM) but not on ATM AND RAD3 RELATED. Kinematic analysis suggested that the delay in the cell cycle leads to a decrease in cell number in fas1 and that loss of ATM partially restores this phenotype. Consistently, both cell size phenotypes and high ploidy phenotypes of fas1 are also suppressed by atm, supporting that the ATM-dependent DNA damage response leads to these phenotypes. Altogether, these data suggest that the ATM-dependent DNA damage response acts as an upstream trigger in fas1 to delay the cell cycle and promote entry into the endocycle, resulting in compensated cell expansion.

Lineage diversification and hybridization in the Cayratia japonica-Cayratia tenuifolia species complex.

The Cayratia japonica-Cayratia tenuifolia species complex (Vitaceae) is distributed from temperate to tropical East Asia, Southeast Asia, India, and Australia. The spatiotemporal diversification history of this complex was assessed through phylogenetic and biogeographic analyses. Maximum parsimony, neighbor-joining, and maximum likelihood methods were used to analyze sequences of one nuclear (AS1) and two plastid regions (trnL-F and trnC-petN). Bayesian dating analysis was conducted to estimate the divergence times of clades. The likelihood method LAGRANGE was used to infer ancestral areas. The Asian C. japonica and C. tenuifolia should be treated as an unresolved complex, and Australian C. japonica is distinct from the Asian C. japonica-C. tenuifolia species complex and should be treated as separate taxa. The Asian C. japonica-C. tenuifolia species complex was estimated to have diverged from its closest relatives during the Late Eocene (35.1 million years ago [Ma], 95% highest posterior densities [HPD]=23.3-47.3Ma) and most likely first diverged in mid-continental Asia. This complex was first divided into a northern clade and a southern clade during the middle Oligocene (27.3Ma; 95% HPD=17.4-38.1Ma), which is consistent with a large southeastward extrusion of the Indochina region relative to South China along the Red River. Each of the northern and southern clades then further diverged into multiple subclades through a series of dispersal and divergence events following significant geological and climatic changes in East and Southeast Asia during the Miocene. Multiple inter-lineage hybridizations among four lineages were inferred to have occurred following this diversification process, which caused some Asian lineages to be morphologically cryptic.