Search

Large exports of land-based contaminants to the ocean exacerbate the effects of climate change, pollute ocean waters, disrupt biogeochemical cycles, harm marine organisms, and consequently jeopardise food security and the livelihoods of ocean-dependent communities. The Canary Current Large Marine Ecosystem (CCLME) is characterised by a mix of the Atlantic Ocean basin waters, reverse flow from the Mediterranean Sea, and inland waters from adjacent countries. This biodiversity-rich ecosystem is a source of ecosystem goods and services that provide sustenance for populations in the coastal states of West Africa and beyond. However, with the ocean surface warming, ocean productivity and fisheries’ outputs have declined across multiple trophic levels. Therefore, in this diagnostic study based on a systematic literature review (publications from 2009 to 2020), we (a) provide an integrative assessment of the CCLME with the exception of Morocco, in the context of the modular large marine ecosystem framework using the categories ‘environmental’ (productivity, fish and fisheries, pollution, and ecosystem health) and ‘non-environmental’ (socioeconomic and governance), and (b) identify knowledge gaps and data scarce regions. The key drivers of change in the CCLME were identified as fishing pressure, land-based pollution, coastal habitat loss, and climate change. Productivity, land-based pollution, and ecosystem health were priority areas for data collection in the CCLME, with data deficiencies particularly apparent in The Gambia and Guinea. Therefore, to mitigate further degradation and accelerate progress toward sustainable management of the CCLME, research should be conducted in these priority areas of data deficiency. Furthermore, as most drivers of change in this ecosystem are related to weak management and a lack of regulatory enforcement, we recommend effective implementation, monitoring, and enforcement of existing national and transboundary regulations, as well as ecosystem-based human-centred management approaches, as proactive strategies for decoupling anthropogenic disturbances from climate change and optimising the productivity of the CCLME.

OZDRAVLJENIK Šta! "Van opasnosti?" Može li uobražena dama Ili nagnuti farisej prestati klevetati? Neće li me izdaja više milovati po ruci, Niti mržnja vrebati me oko vrata? – Nezahvalnost, uz otkazane beneficije, Nije zatvorila puni dlan da napravi pesnicu? Hoće li se zavist ne uzvraćati Za vrline na koje se bilo uzaludno ugledati?

BackgroundViral suppression among people living with HIV (PLHIV) is essential for protecting health and preventing HIV transmission, yet globally, rates of viral suppression are sub-optimal. Interventions to improve HIV prevention and care cascade outcomes remain vital. Financial incentives hold promise for improving these outcomes, yet to date, clinical trial results have been mixed.MethodsThis qualitative sub-study, embedded in a trial (NCT02890459) in Uganda to test whether incentives are effective for achieving viral suppression in PLHIV, sought to enhance our understanding of the factors that influence this outcome. Forty-nine (n = 49) PLHIV, purposely sampled to balance across gender, study arm, and viral suppression status, were interviewed to explore barriers and motivations for care engagement, adherence, and viral suppression, and attributions for decision-making, including perceived influence of incentives on behaviors.ResultsWhile many participants with undetectable viral load (VL) who received incentives said the incentives motivated their ART adherence, others expressed intrinsic motivation for adherence. All felt that incentives reduced burdens of transport costs, lost income due to time spent away from work, and food insecurity. Incentives may have activated attention and memory for some, as excitement about anticipating incentives helped them adhere to medication schedules. In comparison, participants who were randomized to receive incentives but had detectable VL faced a wider range, complexity and severity of challenges to care engagement. Notably, their narratives included more accounts of poor treatment in clinics, food insecurity, and severe forms of stigma. With or without incentives, adherence was reinforced through experiencing restored health due to ART, social support (especially from partners), and good quality counseling and clinical care.ConclusionsIn considering why incentives sometimes fail to achieve behavior change, it may be helpful to attend to the full set of factors- psychological, interpersonal, social and structural- that militate against the behavior change required to achieve behavioral outcomes. To be effective, incentives may need to be combined with other interventions to address the spectrum of barriers to care engagement.

Abstract Background Few studies have explored how economic incentives influence behavioral outcomes. This study aimed to identify pathways of action of an incentives-based intervention to increase men’s participation in HIV testing. Methods The qualitative study was embedded in a randomized-controlled trial that compared effectiveness of gain-framed, loss-framed and lottery-based incentives to increase HIV testing among men. Following testing at a community health campaign, 60 in-depth interviews were conducted with men systematically sampled on the basis of age, incentive group, and campaign attendance. Data were coded deductively and inductively for thematic content analysis. Results Incentives addressed men’s structural, interpersonal and individual-level barriers to testing: offered at convenient locations, incentives offset costs of testing, in lost wages, which are exacerbated when livelihoods required mobility. Interpersonal barriers included anticipated stigma/fear of disclosure, social obligations, and negative peer influences. Providing incentives in public settings provided “social proof” that prizes could be won, and facilitated social support and positive norms by promoting testing with trusted others. Incentives had little influence when men appraised prize values to be low, disbelieved they would win a prize, or were already intrinsically motivated to test. Yet, incentives provided a behavioral ‘cue to action’ for many men who perceived themselves to be susceptible to HIV and perceived HIV disease to be severe, acting as secondary motivator for testing that “sweetened the deal”. Conclusion Incentives can be an important ‘lever’ to promote men’s healthy behaviors in resource-poor settings. HIV testing in convenient, public settings, when paired with incentives, provides multiple pathways to stimulate men’s testing uptake. Trial registration Registered with ClinicalTrials.gov on 08/10/2016, ID: NCT02890459. The first participant was enrolled on 11th April 2016.

In this study, the authors try to examine India's Comprehensive Economic Cooperation Agreement (CECA) with Thailand. This is an inquiry about IndoThailand bilateral trade relations. Time series data for the period between 1997 and 2012 has been taken for the analysis. Here the authors use the well-known Gravity model for sixteen year data analysis. This technique proved to be successful in explaining India's bilateral trade flows to Thailand. The analysis reveals that GDP and Population positively influence trade volume, while distance (dummy) variable shows a negative relationship towards bilateral trade. This paper concludes that India and Thailand have greater unrealized trade potential which can be realized through comprehensive economic cooperation. [ABSTRACT FROM AUTHOR]

Abstract Background It is widely accepted that crop yields will be affected by climate change. However, the role played by climate in affecting crop yields vis-a-vis non-climatic stresses, is often unclear, limiting decision choices around efforts to promote increased production in light of multiple stresses. Results This study quantifies the role of climatic and non-climatic factors affecting multiple crop yields in Uganda, utilizing a systematic approach which involves the use of a two-stage multiple linear regression to identify and characterize the most important drivers of crop yield, examine the location of the key drivers, identify the socio-economic implications of the drivers and identify policy options to enhance agricultural production. We find that non-climatic drivers of crop yields such as forest area dynamics (p = 0.012), wood fuel (p = 0.032) and usage of tractors (0.041) are more important determinants of crop yields than climatic drivers such as precipitation, temperature and CO2 emissions from forest clearance. Climatic drivers are found to multiply existing risks facing production, the significance of which is determined by variability and inadequate distribution of precipitation over the crop growing seasons. Conclusion The significance and validity of these results is observed in an f-statistic of 50 for the final optimized model when compared to the initial model with an f-statistic of 19.3. Research and agricultural policies have to be streamlined to include not only the climatic elements but also the non-climatic drivers of global, regional and national agricultural systems.

The article presents a study which examined exports and imports, and their impact on the balance of trade in India from 1995-1996 to 2009-2010. The commodities exported and imported have increased after the liberalization policy was implemented in 1991, as shown by balance of trade and the share of the Indian economy in the total global trade. The commodities traded are petroleum products, minerals, chemicals, textile products, gems and jewelry, engineering and manufactured goods.

INTRODUCTION: Testicular self-examination (TSE) is a screening technique that involves inspection of the appearance and palpation of the testes to detect any changes from the normal. Globally, the incidence of cancer has increased among which is testicular cancer (TC). Data on this topic among male secondary school adolescents in Uganda is limited therefore this study sought to assess the knowledge and practice of testicular self-examination among secondary students at Ntare School, Mbarara District in south western Uganda. The objective of the study is to assess the knowledge and practice of testicular self-examination among secondary students at Ntare School in Mbarara district, south western Uganda. METHODS: we conducted a descriptive cross-sectional quantitative study among 165 students. Recruitment was made using simple random sampling technique. Respondents were selected among advanced level (A level) male students studying at Ntare School in Mbarara district, south western Uganda. Structured self-administered questionnaires was used for data collection.

Efforts to support the building of resilient pastoralism have been stepped up in Uganda through a number of activities. One of the activity is the provision of seasonal and medium-range climate forecasts to enable decisions concerning livestock herding. Seasonal weather forecasts are critical but there are challenges of timeliness and usability of the forecasts. The challenges are associated with the multiplicity of information sources, methods for data integration and dissemination channels. Institutions including public and Civil Society Organizations usually invest in collecting weather and other data which should be accessible. Often times this data remains hoarded necessitating other organizations to collect similar data. The inter-institutional relations notwithstanding, the lack of data sharing leads to minimal data available for open access. This paper illustrates that this challenge can be addressed by using combined multiple methods to elicit data on weather and other biophysical conditions for pastoralism in Karamoja. In this paper we additionally analyse the opportunities and challenges of using multiple sources of pastoral-relevant data to couple with weather information in support of herding decisions. Building resilient pastoralism that utilizes pasture and water availability will have to utilize available data. It is evident that more robust approaches for data sharing at global, regional and local levels are needed to understand how pastoralists can respond to climate shocks and changes. The paper illustrates the use of a multifaceted-methods approach including open data to develop climate forecast information for risk-reduction oriented information for decision-making. Integration of this data provides insights on how pastoralists have long adapted to a variable and changing climate, the methods and processes of adaptation to losses and damages from the climate shocks.

Abstract Background In addition to breast imaging, ultrasound offers the potential for characterizing and distinguishing between benign and malignant breast tissues due to their different microstructures and material properties. The aim of this study was to determine if high-frequency ultrasound (20-80 MHz) can provide pathology sensitive measurements for the ex vivo detection of cancer in margins during breast conservation surgery. Methods Ultrasonic tests were performed on resected margins and other tissues obtained from 17 patients, resulting in 34 specimens that were classified into 15 pathology categories. Pulse-echo and through-transmission measurements were acquired from a total of 57 sites on the specimens using two single-element 50-MHz transducers. Ultrasonic attenuation and sound speed were obtained from time-domain waveforms. The waveforms were further processed with fast Fourier transforms to provide ultrasonic spectra and cepstra. The ultrasonic measurements and pathology types were analyzed for correlations. The specimens were additionally re-classified into five pathology types to determine specificity and sensitivity values. Results The density of peaks in the ultrasonic spectra, a measure of spectral structure, showed significantly higher values for carcinomas and precancerous pathologies such as atypical ductal hyperplasia than for normal tissue. The slopes of the cepstra for non-malignant pathologies displayed significantly greater values that differentiated them from the normal and malignant tissues. The attenuation coefficients were sensitive to fat necrosis, fibroadenoma, and invasive lobular carcinoma. Specificities and sensitivities for differentiating pathologies from normal tissue were 100% and 86% for lobular carcinomas, 100% and 74% for ductal carcinomas, 80% and 82% for benign pathologies, and 80% and 100% for fat necrosis and adenomas. Specificities and sensitivities were also determined for differentiating each pathology type from the other four using a multivariate analysis. The results yielded specificities and sensitivities of 85% and 86% for lobular carcinomas, 85% and 74% for ductal carcinomas, 100% and 61% for benign pathologies, 84% and 100% for fat necrosis and adenomas, and 98% and 80% for normal tissue. Conclusions Results from high-frequency ultrasonic measurements of human breast tissue specimens indicate that characteristics in the ultrasonic attenuation, spectra, and cepstra can be used to differentiate between normal, benign, and malignant breast pathologies.

The complexation behaviour of Diphenyl viologens (DPVs) with Cucurbit[n]urils (CB[n]) was evaluated in detail and the results were reported. In this work, we present the synthesis of various DPVs functionalised with electron withdrawing and electron donating groups (EWGs & EDGs) and investigate their complexation behaviour with CB[7] and CB [8]. Carboxylic acid functionalized DPV's (DPV-COOH) complexation with CB[8] gives additional insights, i.e., indicates hydrogen bonding plays an effective role in the complexation. The formation of a 2:2 quaternary complex of DPV-COOH/CB[8] under neutral pH conditions was supported by various analytical techniques. The complexation of DPVs with CB[7] specifies that irrespective of the functional group attached, they all form a 1:2 ternary complex, but the findings elaborate that the pattern followed in the complexation depends on the EW or EDG attached to the DPVs. The competition experiments conducted between functionalized DPVs and CB[7], CB[8] shows that they have more affinity towards CB[8] than CB[7] because of the better macrocyclic confinement effect of CB[8], as confirmed using UV-Vis spectroscopy. The binding affinity among EWG and EDG functionalised DPVs with CB[8] concludes EDG functionalised DPVs show better affinity towards CB[8], because they can form a charge transfer complex inside the CB[8] cavity. Exploring these host-guest interactions in more complex biological or environmental settings and studying their impact on the functionality of DPVs could be an exciting avenue for future research., (© 2024. The Author(s).)

Hybrid solid polymer electrolytes (HSPE) comprising poly(ethylene oxide) (PEO), LiTFSI, barium titanate (BaTiO 3 ), and viologen are prepared by a facile hot press. The physical properties of the HSPE membranes are studied by using small-angle and wide-angle X-ray scattering, thermogravimetric analysis, differential scanning calorimetry, and tensile strength. The prepared hybrid solid polymer electrolytes are also investigated by means of ionic conductivity and transport number measurements. The employed analyses collectively reveal that each additive in the PEO host contributes to a specific property: LiTFSI is essential in providing ionic species, while BaTiO 3 and viologen enhance the thermal stability, ionic conductivity, and transport number. The enhanced value in the Li + -transport number of HSPE are presumably attributed to the electrostatic attraction of TFSI anions and the positive charges of viologen. Synergistically, the added BaTiO 3 and viologen improve the electrochemical properties of HSPE for the applications in all-solid-state-lithium polymer batteries., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever-increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that employ smFRET approaches have joined forces to inform the smFRET community about streamlining how to perform experiments and analyze results for obtaining quantitative information on biomolecular structure and dynamics. The recent efforts include blind tests to assess the accuracy and the precision of smFRET experiments among different labs using various procedures. These multi-lab studies have led to the development of smFRET procedures and documentation, which are important when submitting entries into the archiving system for integrative structure models, PDB-Dev. This position paper describes the current 'state of the art' from different perspectives, points to unresolved methodological issues for quantitative structural studies, provides a set of 'soft recommendations' about which an emerging consensus exists, and lists openly available resources for newcomers and seasoned practitioners. To make further progress, we strongly encourage 'open science' practices., Competing Interests: EL, AB, JH, BA, VB, SB, RB, HS, TC, TC, AD, JD, JF, RG, IG, TH, CH, GH, NH, SH, SH, TH, AI, CJ, AK, HK, TL, NL, TL, EL, EM, JM, XM, SM, DN, TP, EP, YR, NR, BS, HS, CT, RV, DL, CS, SW No competing interests declared

Single-molecule Förster Resonance Energy Transfer (smFRET) is a powerful technique capable of resolving both relative and absolute distances within and between structurally dynamic biomolecules. High instrument costs, and a lack of open-source hardware and acquisition software have limited smFRET's broad application by non-specialists. Here, we present the smfBox, a cost-effective confocal smFRET platform, providing detailed build instructions, open-source acquisition software, and full validation, thereby democratising smFRET for the wider scientific community.

Flavored cigar use is common among cigar smokers, particularly those at younger ages. Several US localities have implemented policies restricting the sale of flavored tobacco products, including cigars. We estimated the population health benefits of removal of flavored cigars throughout the US in terms of reductions in cigar smoking-attributable mortality due to increased cessation and reductions in cigar smoking prevalence due to decreased initiation and continuing use. Monte Carlo simulation was used to estimate possible ranges for these values. We used published estimates of cigar use and attributable mortality in the US, as well as prior study conclusions on the effect of local and national flavor restriction policies. We estimated that removal of flavored cigars would result in approximately 800 (90% prediction interval = 400-1200) fewer cigar smoking-attributable deaths in the US each year and 112,000 fewer cigar smokers (90% prediction interval = 76,000-139,000) in each cohort of 18 year olds. The removal of characterizing flavors in cigars sold in the US is thus projected to have substantial public health benefits over time.

Importance: Use of electronic cigarettes (e-cigarettes) is increasing. Measures of exposure to known tobacco-related toxicants among e-cigarette users will inform potential health risks to individual product users., Objectives: To estimate concentrations of tobacco-related toxicants among e-cigarette users and compare these biomarker concentrations with those observed in combustible cigarette users, dual users, and never tobacco users., Design, Setting, and Participants: A population-based, longitudinal cohort study was conducted in the United States in 2013-2014. Cross-sectional analysis was performed between November 4, 2016, and October 5, 2017, of biomarkers of exposure to tobacco-related toxicants collected by the Population Assessment of Tobacco and Health Study. Participants included adults who provided a urine sample and data on tobacco use (N = 5105)., Exposures: The primary exposure was tobacco use, including current exclusive e-cigarette users (n = 247), current exclusive cigarette smokers (n = 2411), and users of both products (dual users) (n = 792) compared with never tobacco users (n = 1655)., Main Outcomes and Measures: Geometric mean concentrations of 50 individual biomarkers from 5 major classes of tobacco product constituents were measured: nicotine, tobacco-specific nitrosamines (TSNAs), metals, polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs)., Results: Of the 5105 participants, most were aged 35 to 54 years (weighted percentage, 38%; 95% CI, 35%-40%), women (60%; 95% CI, 59%-62%), and non-Hispanic white (61%; 95% CI, 58%-64%). Compared with exclusive e-cigarette users, never users had 19% to 81% significantly lower concentrations of biomarkers of exposure to nicotine, TSNAs, some metals (eg, cadmium and lead), and some VOCs (including acrylonitrile). Exclusive e-cigarette users showed 10% to 98% significantly lower concentrations of biomarkers of exposure, including TSNAs, PAHs, most VOCs, and nicotine, compared with exclusive cigarette smokers; concentrations were comparable for metals and 3 VOCs. Exclusive cigarette users showed 10% to 36% lower concentrations of several biomarkers than dual users. Frequency of cigarette use among dual users was positively correlated with nicotine and toxicant exposure., Conclusions and Relevance: Exclusive use of e-cigarettes appears to result in measurable exposure to known tobacco-related toxicants, generally at lower levels than cigarette smoking. Toxicant exposure is greatest among dual users, and frequency of combustible cigarette use is positively correlated with tobacco toxicant concentration. These findings provide evidence that using combusted tobacco cigarettes alone or in combination with e-cigarettes is associated with higher concentrations of potentially harmful tobacco constituents in comparison with using e-cigarettes alone.

Human flap endonuclease-1 (hFEN1) catalyzes the divalent metal ion-dependent removal of single-stranded DNA protrusions known as flaps during DNA replication and repair. Substrate selectivity involves passage of the 5'-terminus/flap through the arch and recognition of a single nucleotide 3'-flap by the α2-α3 loop. Using NMR spectroscopy, we show that the solution conformation of free and DNA-bound hFEN1 are consistent with crystal structures; however, parts of the arch region and α2-α3 loop are disordered without substrate. Disorder within the arch explains how 5'-flaps can pass under it. NMR and single-molecule FRET data show a shift in the conformational ensemble in the arch and loop region upon addition of DNA. Furthermore, the addition of divalent metal ions to the active site of the hFEN1-DNA substrate complex demonstrates that active site changes are propagated via DNA-mediated allostery to regions key to substrate differentiation. The hFEN1-DNA complex also shows evidence of millisecond timescale motions in the arch region that may be required for DNA to enter the active site. Thus, hFEN1 regional conformational flexibility spanning a range of dynamic timescales is crucial to reach the catalytically relevant ensemble.

In flowering plants, arguably the most significant transcription factors regulating development are MADS-domain proteins, encoded by Type I and Type II MADS-box genes. Type II genes are divided into the MIKC(C) and MIKC* groups. In angiosperms, these types and groups play distinct roles in the development of female gametophytes, embryos, and seeds (Type I); vegetative and floral tissues in sporophytes (MIKC(C)); and male gametophytes (MIKC*), but their functions in other plants are largely unknown. The complete set of MADS-box genes has been described for several angiosperms and a moss, Physcomitrella patens. Our examination of the complete genome sequence of a lycophyte, Selaginella moellendorffii, revealed 19 putative MADS-box genes (13 Type I, 3 MIKC(C), and 3 MIKC*). Our results suggest that the most recent common ancestor of vascular plants possessed at least two Type I and two Type II genes. None of the S. moellendorffii MIKC(C) genes were identified as orthologs of any floral organ identity genes. This strongly corroborates the view that the clades of floral organ identity genes originated in a common ancestor of seed plants after the lineage that led to lycophytes had branched off, and that expansion of MIKC(C) genes in the lineage leading to seed plants facilitated the evolution of their unique reproductive organs. The number of MIKC* genes and the ratio of MIKC* to MIKC(C) genes is lower in S. moellendorffii and angiosperms than in P. patens, correlated with reduction of the gametophyte in vascular plants. Our data indicate that Type I genes duplicated and diversified independently within lycophytes and seed plants. Our observations on MADS-box gene evolution echo morphological evolution since the two lineages of vascular plants appear to have arrived independently at similar body plans. Our annotation of MADS-box genes in S. moellendorffii provides the basis for functional studies to reveal the roles of this crucial gene family in basal vascular plants.

A 9-week-old kitten was diagnosed with a congenital vascular ring anomaly by means of an esophageal contrast study. At 6 mo of age, a non-selective vascular study was used to diagnose a persistent right aortic arch (PRAA). Left-sided thoracoscopic surgery was performed, using a Liga-Sure vessel sealant device to seal and transect the ligamentum arteriosum.

Symbiotic associations between plants and fungi are a dominant feature of many terrestrial ecosystems, yet relatively little is known about the signaling, and associated transcriptome profiles, that define the symbiotic metabolic state. Using the Epichloë festucae-perennial ryegrass (Lolium perenne) association as a model symbiotic experimental system, we show an essential role for the fungal stress-activated mitogen-activated protein kinase (sakA) in the establishment and maintenance of this mutualistic interaction. Deletion of sakA switches the fungal interaction with the host from mutualistic to pathogenic. Infected plants exhibit loss of apical dominance, premature senescence, and dramatic changes in development, including the formation of bulb-like structures at the base of tillers that lack anthocyanin pigmentation. A comparison of the transcriptome of wild-type and sakA associations using high-throughput mRNA sequencing reveals dramatic changes in fungal gene expression consistent with the transition from restricted to proliferative growth, including a down-regulation of several clusters of secondary metabolite genes and up-regulation of a large set of genes that encode hydrolytic enzymes and transporters. Analysis of the plant transcriptome reveals up-regulation of host genes involved in pathogen defense and transposon activation as well as dramatic changes in anthocyanin and hormone biosynthetic/responsive gene expression. These results highlight the fine balance between mutualism and antagonism in a plant-fungal interaction and the power of deep mRNA sequencing to identify candidate sets of genes underlying the symbiosis.

Lolitrem B is synthesized by Epichloë festucae in associations with Pooid grasses. A complex cluster of at least 10 genes (ltm genes) is required for its synthesis. An early step in this pathway is catalyzed by ltmM, a symbiosis-expressed gene. PltmM-gusA reporter gene analysis was used to monitor ltmM gene expression patterns in planta. The minimum promoter length required for high-level gusA expression in infected seedlings is in the range of 480 to 782 bp. gusA was expressed by the endophyte in all infected vegetative plant tissues and in epiphyllous hyphae. Spikelets from reproductive tillers were analyzed at different developmental stages. During pre-anthesis, gusA expression was observed in all infected floral organs except the immature gynoecium. In post-anthesis florets, gene expression occurred almost exclusively in the gynoecium. Expression of gusA by the endophyte was observed in germinating seeds 24 h postimbibition and seedlings older than 6 days postimbibition in hyphae from the mesocotyl to the tip of the emerging first leaf. This work provides a detailed analysis of the spatial and temporal expression patterns of a symbiosis-expressed gene in planta.

The degree to which the eudicot-based ABC model of flower organ identity applies to the other major subclass of angrosperms, the monocots, has yet to be fully explored. We cloned silky1 (si1), a male sterile mutant of Zea mays that has homeotic conversions of stamens into carpels and lodicules into palea/lemma-like structures. Our studies indicate that si1 is a monocot B function MADS box gene. Moreover, the si1 zag1 double mutant produces a striking spikelet phenotype where normal glumes enclose reiterated palea/lemma-like organs. These studies indicate that B function gene activity is conserved among monocots as well as eudicots. In addition, they provide compelling developmental evidence for recognizing lodicules as modified petals and, possibly, palea and lemma as modified sepals.

The Arabidopsis gene AGAMOUS is required for male and female reproductive organ development and for floral determinacy. Reverse genetics allowed the isolation of a transposon-induced mutation in ZAG1, the maize homolog of AGAMOUS. ZAG1 mutants exhibited a loss of determinacy, but the identity of reproductive organs was largely unaffected. This suggested a redundancy in maize sex organ specification that led to the identification and cloning of a second AGAMOUS homolog, ZMM2, that has a pattern of expression distinct from that of ZAG1. C-function organ identity in maize (as defined by the A, B, C model of floral organ development) may therefore be orchestrated by two closely related genes, ZAG1 and ZMM2, with overlapping but nonidentical activities.