A dual-targeting PDGFRβ/VEGF-A molecule assembled from stable antibody fragments demonstrates anti-angiogenic activity in vitro and in vivo

Targeting angiogenesis is a promising approach to the treatment of solid tumors and age-related macular degeneration (AMD). Inhibition of vascularization has been validated by the successful marketing of monoclonal antibodies (mAbs) that target specific growth factors or their receptors, but there is considerable room for improvement in existing therapies. Combination of mAbs targeting both the VeGF and pDGF pathways has the potential to increase the efficacy of anti-angiogenic therapy without the accompanying toxicities of tyrosine kinase inhibitors and the inability to combine efficiently with traditional chemotherapeutics. However, development costs and regulatory issues have limited the use of combinatorial approaches for the generation of more efficacious treatments.The concept of mediating disease pathology by targeting two antigens with one therapeutic was proposed over two decades ago. While mAbs are particularly suitable candidates for a dual-targeting approach, engineering bispecificity into one molecule can be difficult due to issues with expression and stability, which play a significant role in manufacturability. Here, we address these issues upstream in the process of developing a bispecific antibody (bsAb). Single-chain antibody fragments (scFvs) targeting pDGFRβ and VeGF-A were selected for superior stability. the scFvs were fused to both termini of human Fc to generate a bispecific, tetravalent molecule. resulting molecule displays potent activity, binds both targets simultaneously, and is stable in serum. assembly of a bsAb using stable monomeric units allowed development of an anti-pDGFRB/VeGF-A antibody capable of attenuating angiogenesis through two distinct pathways and represents an efficient method for rapid engineering of dual-targeting molecules.Key words: bispecific, antibody, PDGFRβ, VEGF-A, stability, angiogenesis     

Species traits affect the performance of species distribution models for plants in southern California

Questions: To what extent do plant species traits, including life history, life form, and disturbance response characteristics, affect the degree to which species distributions are determined by physical environmental factors? Is the strength of the relationship between species distribution and environment stronger in some disturbance‐response types than in others? Location: California southwest ecoregion, USA. Methods: We developed species distribution models (SDMs) for 45 plant species using three primary modeling methods (GLMs, GAMs, and Random Forests). Using AUC as a performance measure of prediction accuracy, and measure of the strength of species–environment correlations, we used regression analyses to compare the effects of fire disturbance response type, longevity, dispersal mechanism, range size, cover, species prevalence, and model type. Results: Fire disturbance response type explained more variation in model performance than any other variable, but other species and range characteristics were also significant. Differences in prediction accuracy reflected variation in species life history, disturbance response, and rarity. AUC was significantly higher for longer‐lived species, found at intermediate levels of abundance, and smaller range sizes. Models performed better for shrubs than sub‐shrubs and perennial herbs. The disturbance response type with the highest SDM accuracy was obligate‐seeding shrubs with ballistic dispersal that regenerate via fire‐cued germination from a dormant seed bank. Conclusions: The effect of species characteristics on predictability of species distributions overrides any differences in modeling technique. Prediction accuracy may be related to how a suite of species characteristics co‐varies along environmental gradients. Including disturbance response was important because SDMs predict the realized niche. Classification of plant species into disturbance response types may provide a strong framework for evaluating performance of SDMs.     

Pollination ecology of Isoglossa woodii,a long‐lived,synchronously monocarpic herb from coastal forests in South Africa

Synchronous monocarpy in long‐lived plants is often associated with pollination by wind, in part because infrequent mass flowering may satiate pollinators. Selfing in synchronous monocarps may provide reproductive assurance but conflict with the benefits of outcrossing, a key evolutionary driver of synchrony. We predicted that animal‐pollinated species with synchronous flowering would have unspecialised flowers and attract abundant generalised pollinators, but predictions for selfing and outcrossing frequencies were not obvious. We examined the pollination biology of Isoglossa woodii (Acanthaceae), an insect‐pollinated, monocarpic herb that flowers synchronously at 4–7‐year intervals. The most frequent visitor to I. woodii flowers was the African honeybee, Apis mellifera adansonii. Hand‐pollination failed to enhance seed production, indicating that the pollinators were not saturated. No seed was set in the absence of pollinators. Seed set was similar among selfed and outcrossed flowers, demonstrating a geitonogamous mixed‐mating strategy with no direct evidence of preferential outcrossing. Flowers contained four ovules, but most fruits only developed one seed, raising the possibility that preferential outcrossing occurs by post‐pollination processes. We argue that a number of the theoretical concerns about geitonogamous selfing as a form of reproductive assurance do not apply to a long‐lived synchronous monocarp such as I. woodii.     

Remyelination — An effective means of neuroprotection

Remyelination following central nervous system (CNS) demyelination restores rapid saltatory conduction of action potentials and contributes to the maintenance of axonal integrity. This robust regenerative phenomenon stands in contrast to the limited repair capacity that is characteristic of CNS neuronal injury. However, despite its efficiency in experimental models and some clinical diseases, remyelination failure becomes an increasingly pronounced feature of the pathology of chronic multiple sclerosis (MS) lesions. Chronic demyelination predisposes axons to atrophy, an irreversible event that is a major pathological correlate of progressive functional decline. This has created a compelling case for developing therapies that promote remyelination: evidence from experimental animal models suggests that hormones may have a beneficial role to play in this regard.     

Population Dynamics of Spotted Owls in the Sierra Nevada,California

ABSTRACT The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southem Cascades and Sierra Nevada, California, USA, from 1990 to 2005 to assist a listing evaluation by the United States Fish and Wildlife Service. Our study areas (from N to S) were on the Lassen National Forest (LAS), Eldorado National Forest (ELD), Sierra National Forest (SIE), and Sequoia and Kings Canyon National Parks (SKC). These study areas represented a broad spectrum of habitat and management conditions in these mountain ranges. We estimated apparent survival probability, reproductive output, and rate of population change for spotted owls on individual study areas and for all study areas combined (meta-analysis) using model selection or model-averaging based on maximum-likelihood estimation. We followed a formal protocol to conduct this analysis that was similar to other spotted owl meta-analyses. Consistency of field and analytical methods among our studies reduced confounding methodological effects when evaluating results. We used 991 marked spotted owls in the analysis of apparent survival. Apparent survival probability was higher for adult than for subadult owls. There was little difference in apparent survival between male and female owls. Model-averaged mean estimates of apparent survival probability of adult owls varied from 0.811 ± 0.021 for females at LAS to 0.890 ± 0.016 for males at SKC. Apparent survival increased over time for owls of all age classes at LAS and SIE, for adults at ELD, and for second-year subadults and adults at SKC. The meta-analysis of apparent survival, which included only adult owls, confirmed an increasing trend in survival over time. Survival rates were higher for owls on SKC than on the other study areas. We analyzed data from 1,865 observations of reproductive outcomes for female spotted owls. The proportion of subadult females among all territorial females of known age ranged from 0.00 to 0.25 among study areas and years. The proportion of subadults among female spotted owls was negatively related to reproductive output (no. of young fledged/territorial F owl) for ELD and SIE. Eldorado study area and LAS showed an alternate-year trend in reproductive output, with higher output in even-numbered years. Mean annual reproductive output was 0.988 ± 0.154 for ELD, 0.624 ± 0.140 for LAS, 0.478 ± 0.106 for SIE, and 0.555 ± 0.110 for SKC. Eldorado Study Area exhibited a declining trend and the greatest variation in reproductive output over time, whereas SIE and SKC, which had the lowest reproductive output, had the lowest temporal variation. Meta-analysis confirmed that reproductive output varied among study areas. Reproductive output was highest for adults, followed by second-year subadults, and then by first-year subadults. We used 842 marked subadult and adult owls to estimate population rate of change. Modeling indicated that Λ _t (Λ _t is the finite rate of population change estimated using the reparameterized Jolly–Seber estimator [Pradel 1996]) was either stationary (LAS and SIE) or increasing after an initial decrease (ELD and SKC). Mean estimated Λ _t for the 4 study areas was 1.007 (95% CI = 0.952–1.066) for ELD; 0.973 (95% CI = 0.946–1.001) for LAS; 0.992 (95% CI = 0.966–1.018) for SIE; and 1.006 (95% CI = 0.947–1.068) for SKC. The best meta-analysis model of population trend indicated that Λ varied across time but was similar in trend among the study areas. Our estimates of realized population change (Δ _t ; Franklin et al. 2004), which we estimated as the product 1 λ₃, were based on estimates of Λ _t from individual study areas and did not require estimating annual population size for each study area. Trends represented the proportion of the population size in the first year that remained in each subsequent year. Similar to λ₄ on which they were based, these λ_k-1 showed evidence of decline over the study period for LAS and SIE. The best model indicated recruitment of male and female adult and subadults varied from 0.10 to 0.31 new territorial individuals at time t/number of territorial individuals at time t–1 and similarly among areas. We also conducted a population viability analysis (PVA) based on results of our meta-analysis. This PVA was of limited utility for ELD and SKC study areas because 95% confidence intervals on the probability of decline or increase spanned the interval [0, 1] within 5–10 years. When we restricted inferences to 7 years, estimated probability of a >10% decline for SIE was 0.41 (95% CI = 0.09–0.78); for LAS the probability was 0.64 (95% CI = 0.27–0.94). In contrast, estimated probability of a >10% increase in 7 years for SIE was 0.23 (95% CI = 0.01–0.55) and for LAS was 0.10 (95% CI = 0.00–0.34). For comparisons, we simulated a PVA for a hypothetical population with mean Λ = 1.0 and the same temporal variation as observed in our owl populations. Our PVA suggested that both the SIE and LAS populations had higher probabilities of declining in a 7-year period than increasing but that it would be difficult to determine if a population was in a slight gradual decline. Our analysis and the repository of information on our 4 study populations provide a data-rich template for managers to monitor impacts of future management actions on the owl. Specifically, our data can be used to evaluate the effect of management strategies on spotted owls that are being implemented by the United States Forest Service to reduce the risk of wildfire in the Sierra Nevada ecosystem. Our information also provides baseline information for evaluating the status of the owl for potential listing as a threatened species by the United States Fish and Wildlife Service. RESUMEN El búho californiano manchado (Strix occidentalis occidentalis) es la única subespecie de búhos manchados que no está listada como amenazada o en peligro de extinción en el Acta de E.E.U.U. para las Especies en Peligro de Extinción a pesar de las peticiones para que sea incluida en la lista como una especie amenazada. Nosotros realizamos un meta-análisis de los datos de la población de 4 poblaciones del sur de Cascades y de la Sierra Nevada, California desde 1990 hasta 2005 como ayuda a una evaluación de listado hecha por el U.S Fish and Wildlife Service. Nuestras áreas de estudio (de norte a sur) estuvieron localizadas en el Bosque Nacional Lassen (LAS), en el Bosque Nacional Eldorado (ELD), en el Bosque Nacional Sierra (SIE) y en los Parques Nacionales Sequoia y Kings Canyon (SKC). Estas áreas de estudio representaron un amplio espectro del hábitat y de las condiciones de manejo en estas cadenas de montañas. Nosotros calculamos la probabilidad de supervivencia aparente, el volumen de reproducción y el cambio en la tasa de población de los búhos manchados en áreas de estudio individuales y para todas las áreas de estudio combinadas (meta-análisis) utilizando selección de modelos o promediando modelos basados en la estimación de máxima probabilidad. Seguimos un protocolo formal para realizar este análisis que fuera similar a otros meta-análisis con búhos manchados. La consistencia del campo y los métodos analíiticos en nuestros estudios redujeron la confusión de efectos metodológicos al evaluar los resultados. Utilizamos 991 búhos manchados marcados en el análisis de supervivencia aparente. La probabilidad de supervivencia aparente fue más alta para búhos adultos que para subadultos. Hubo poca diferencia en la supervivencia aparente entre hembras y machos. Para los modelos promediados, los cálculos de la media de la probabilidad de supervivencia aparente para búhos adultos tuvo una variación de 0.811 ± 0.021 para hembras en LAS a 0.890 ± 0.016 para machos en SKA. La supervivencia aparente aumentó con el tiempo para los búhos de todos los grupos de edad en LAS y SIE, para adultos en ELD, y para subadultos del segundo año y para adultos en SKC. El meta-análisis de supervivencia aparente, que incluyó únicamente a búhos adultos, confirmó una tendencia al aumento en la supervivencia con el tiempo. Las tasas de supervivencia fueron más altas para los búhos en SKC que en las otras áreas de estudio. Analizamos información de 1.865 observaciones de resultados de reproducciones para búhos manchados hembra. La proporción de hembras subadultas entre todas las hembras territoriales de edad conocida fluctuó de 0.00 a 0.25 a través de las áreas de estudio y de los años. La proporción de subadultos entre los búhos manchados hembra estuvo relacionada negativamente con el volumen de reproducción (número de pichones emplumados por búho hembra territorial) para ELD y SIE. ELD y LAS mostraron una tendencia anual alternada en el volumen de reproducción, con un volumen mayor en los años pares. La media del volumen de reproducción anual fue 0.988 ± 0.154 para ELD, 0.624 ± 0.140 para LAS, 0.478 ± 0.106 para SIE y 0.555 ± 0.154 para SKC. ELD exhibió una tendencia a disminuir y la variación más alta en el volumen de reproducción a través del tiempo; mientras que SIE y SKC, que tuvieron el más bajo volumen de reproducción, tuvieron la menor variación temporal. El meta-análisis confirmó que el volumen de reproducción varió entre las áreas de estudio. El volumen de reproducción fue más alto para adultos, seguido por subadultos del segundo año, y luego por subadultos del primer año. Nosotros utilizamos 842 búhos marcados, adultos y subadultos, para calcular el índice de cambio de la población. La selección de modelos indicó que Λ _t era, o relativamente fija (LAS y SIE) o aumentaba después de una disminución inicial (ELD y SKC). La media calculada Λ _t para las cuatro áreas de estudio fue: 1.007 (95% CI = 0.952–1.066) para ELD; 0.973 (95% CI = 0.946–1.001) para LAS; 0.992 (95% CI = 0.966–1.018) para SIE; y 1.006 (95% CI = 0.947–1.068) para SKC. El mejor modelo de meta-análisis de la tendencia de población indicó que Λ variaba con el tiempo pero que era una tendencia similar entre las áreas de estudio. Nuestros cálculos sobre el cambio de población realizado (Δ _t ) se basaron en los cálculos de Λ _t de las áreas de estudio individuales y no requirieron calcular el tamaño de la población anual para cada área de estudio. Las tendencias representaron la proporción del tamaño de la población en el primer año que permaneció en cada año subsiguiente. De manera similar a λ_t, en la que se basaron, éstas Δ_t mostraron evidencia de disminución durante el período de estudio para LAS y SIE. El mejor modelo de reclutamiento indicado, el reclutamiento de búhos machos y hembras, adultos y subadultos, varió de 0.10 a 0.31 individuos territoriales nuevos al tiempo t por el número de individuos territoriales al tiempo t–1 y de manera similar entre las otras áreas. También realizamos un análisis de viabilidad de población (PVA) basado en los resultados de nuestro meta-análisis. Este análisis PVA fue de limitada utilidad para las áreas de estudio ELD y SKC porque el 95% de intervalos de confiabilidad en la probabilidad de disminución o aumento extendió el intervalo [0, 1] de 5–10 años. Cuando restringimos las inferencias a 7 años, la probabilidad estimada de a >10% de disminución para SIE fue 0.41 (95% CI = 0.09–0.78); para LAS la probabilidad fue 0.64 (95% CI = 0.27–0.94). En contraste, la probabilidad estimada de un >10% de aumento en 7 años para SIE fue 0.23 (95% CI = 0.01–0.55) y para LAS fue 0.10 (95% CI = 0.00–0.34). Para comparar, simulamos un PVA para una población hipotética con una media Λ = 1.0, y con la misma variación temporal observada en nuestras poblaciones de búhos. Nuestro PVA sugirió que ambas poblaciones SIE y LAS tenían, en un período de 7 años, mayores probabilidades de disminución que de aumento, pero que sería muy difícil determinar si alguna de las poblaciones estaba en una ligera disminución gradual. El depósito de información de nuestras 4 áreas de estudio provee una plantilla rica en información para que los administradores monitoreen los impactos de acciones futuras en el manejo de los búhos (por ejemplo, nuevas estrategias de manejo del Plan de Sierra Nevada Forest). También provee evidencia importante para evaluar el estatus del búho para su potencial inclusión en el listado de especies amenazadas. RÉSUMÉ Le hibou tacheté californien (Strix occidentalis occidentalis) est la seule sous-espèce de hibou tacheté ne figurant pas sur la liste des animaux menacés ou vulnérables sous la Loi des Espèces en Danger des Etats-Unis malgré des pétitions pour l'inscrire sur cette liste en tant que sous-espèce menacée. Nous avons effectué une méta-analyse des données de population pour 4 populations dans le sud des Cascades et dans la Sierra Nevada, en Californie de 1990 à 2005 pour aider une évaluation de leur statut établie par les Services des Eaux et Forêts des Etats-Unis. Nos aires d'étude (du nord au sud) étaient dans la forêt nationale Lassen (LAS), la forêt nationale Eldorado (ELD), la forêt nationale Sierra (SIE), et les parcs nationaux Sequoia et Kings Canyon (SKC). Ces aires d'étude représentaient un large échantillon des conditions de l'habitat et de la gestion dans ces chaînes de montagnes. Nous avons estimé la probabilité de survie apparente, le succès de reproduction, et le taux de changement de la population pour les hiboux tachetés dans chaque aire d'étude individuelle et dans toutes les aires réunies (méta–analyse) en utilisant la sélection de modèles ou le calcul de la moyenne des modèles basé sur une estimation du maximum de vraisemblance. Pour effectuer cette analyse nous avons suivi un protocole rigoureux similaire à d'autres méta-analyses de hiboux tachetés. La cohérence des observations de terrain et des méthodes analytiques entre ces études a réduit les effets méthodologiques confondants lors des évaluations des résultats. Nous avons utilisé 991 hiboux tachetés marqués dans l'analyse de survie apparente. La probabilité de survie apparente a été plus élevée pour les hiboux adultes que pour les sous-adultes. Il y a eu peu de différence pour ce qui est de la survie apparente entre les hiboux mâles et femelles. La moyenne des estimations de la probabilité de survie apparente des hiboux adultes basée sur la moyenne des modèles a varié entre 0,811 ± 0,021 pour les hiboux femelles à LAS et 0,890 ± 0,016 pour les hiboux mâles à SKC. La survie apparente a augmenté avec le temps pour les hiboux de toutes les classes d'âge à LAS et SIE, pour les adultes à ELD, et pour les sous-adultes de deux ans et les adultes à SKC. La méta-analyse de survie apparente, qui comprenait seulement des hiboux adultes, a confirmé une tendance croissante de survie avec le temps. Les taux de survie étaient plus élevés pour les hiboux de SKC que pour ceux des autres aires d'étude. Nous avons analysé les données obtenues à partir de 1 865 observations de succès de reproduction de hiboux tachetées femelles. La proportion des hiboux femelles sous-adultes parmi toutes les femelles territoriales d'àge connu a varié de 0,00 à 0,25 selon les aires et les années d'étude. La proportion des sousadultes parmi les hiboux tachetés femelles a été négativement corrélée avec le succès de reproduction (nombre de jeunes hiboux par femelle territoriale) pour ELD et SIE. La forêt nationale Eldorado et la forêt nationale Lassen ont montré une tendance à alterner selon un cycle biennal pour ce qui est du succès de reproduction, avec un taux plus élevé pendant les années paires. La moyenne du succès de reproduction annuel était de 0,988 ± 0,154 pour ELD, de 0,624 ± 0,140 pour LAS, de 0,478 ± 0,106 pour SIE, et de 0,555 ± 0,110 pour SKD. La forêt nationale Eldorado a montré une tendance décroissante ainsi que la plus grande variation dans le succès de reproduction avec le temps, alors que SIE et SKC, qui ont eu le succès de reproduction le plus bas, ont connu la variation temporelle la plus basse. La méta-analyse a confirmé que le succès de reproduction variait selon les aires d'étude. Le succès de reproduction a été le plus élevé pour les adultes, puis pour les sous-adultes de deux ans, et ensuite pour les sous-adultes d'un an. Nous avons utilisé 842 hiboux marqués, adultes et sous-adultes, pour estimer le taux de changement de la population. La modélisation a indiqué que Λ _t était soit stationnaire (LAS et SIE), soit croissant après une baisse initiale (ELD et SKC). La moyenne estimée Λ _t pour les 4 aires d'étude était: 1,007 (95% IC = 0,952–1,066) pour ELD; 0,973 (95% IC = 0,946–1,001) pour LAS; 0,992 (95% IC = 0,966–1,018) pour SIE; et 1,006 (95% IC = 0,947–1,068) pour SKC. Le meilleur modèle de méta-analyse pour la tendance de la population a indiqué que Λ variait selon le temps mais suivait la même tendance selon les aires d'étude. Nos estimations du changement de population réalisé (Δ _t ) étaient fondées sur les estimations de Λ _t des aires d'étude individuelles et n'ont pas nécessité d'estimation de la taille annuelle de la population pour chaque aire d'étude. Les tendances représentaient la proportion de la taille de la population pendant la première année qui s'est maintenue chaque année subséquente. De même que λ_t sur lesquels ils étaient fondés, ces δ_t ont apporté des preuves de déclin pendant la période d'étude pour LAS et SIE. Le meilleur modèle a indiqué que le recrutement des hiboux adultes et sous-adultes mâles et femelles variait de 0,10 à 0,31 nouveaux individus territoriaux à un temps t pour un nombre d'individus territoriaux à un temps t-1 et qu'il en était de même dans chaque aire. Nous avons également procédé à une analyse de viabilité de la population (AVP) fondée sur les résultats de notre méta-analyse. Cette AVP a été d'une utilité limitée pour les aires d'étude ELD et SKC parce que les intervalles de confiance de 95% sur la probabilité du déclin ou de la croissance couvraient l'intervalle [0, 1] sur une période de 5 à 10 ans. Lorsque nous avons réduit les inférences à 7 ans, la probabilité estimée d'un déclin >10% pour SIE était de 0,41 (95% IC = 0,09–0,78); pour LAS la probabilité était de 0,64 (95% IC = 0,27–0,94). Al'opposé, la probabilité estimée d'une croissance >10% en 7 ans pour SIE était de 0,23 (95% IC = 0,01–0,55) et pour LAS elle était de 0,10 (95% IC = 0,00–0,34). Afin de comparer, nous avons simulé une AVP pour une population hypothétique ayant une moyenne Λ = 1,0 et la même variation temporelle que celle observée dans nos populations de hiboux. Notre AVP a suggéré que les populations de SIE et de LAS avaient de plus grandes probabilités de déclin que de croissance sur une période de 7 ans, mais qu'il serait difficile de déterminer si une population présentait un léger déclin graduel. La collecte des informations pour nos 4 aires d'étude foumit aux personnes chargées de la gestion un modèle riche de données permettant de suivre l'impact sur les hiboux des actions de gestion à l'avenir (par exemple, les nouvelles stratégies de gestion du Plan pour la Forêt de Sierra Nevada). Cette collecte foumit également des preuves importantes afin d'évaluer le statut du hibou pour une classification potentielle sur la liste des espèces menacées.     

Association between occupation and knee and hip replacement due to osteoarthritis: a case-control study

Introduction  

The objective of this study was to examine the association between occupation and osteoarthritis (OA) leading to total knee (TKR) or hip (THR) joint replacement.     

Structural and Functional Responses of a Sewage Microbial Community to Dilution-Induced Reductions in Diversity

The relationship between functional redundancy and microbial community structure–diversity was examined using laboratory incubations to ensure constant environmental conditions. Serial dilutions of a sewage microbial community were prepared, used to inoculate sterile sewage, and maintained in batch culture. Probability suggests that dilution of the initial community should remove rare organism types, creating mixtures of cells differing in diversity. Regrowth of the diluted mixtures generated communities similar in abundance but differing in community structure and relative diversity (as determined using two DNA fingerprinting techniques and dilution-to-extinction analysis of community-level physiological profiles). The in situ function of each regrown community was examined by monitoring the short-term uptake of five different ¹⁴C-labeled compounds (glucose, acetate, citrate, palmitic acid, and an amino acid mixture). No significant differences were detected between treatments in either the rate of uptake of a substrate or the efficiency with which each community assimilated each compound. The fact that the activity of the original community was the same as that of a community regrown from an inoculum containing fewer that 100 cells (10⁻⁶ dilution) indicates that functional redundancy was quite high in this system. For each organism type eliminated during the dilution process, at least one of the remaining types was able to provide the same function at the same level as the lost one. Further research is necessary to determine what impact this functional redundancy may have on overall ecosystem function and stability.     

Auxin pretreatment promotes regeneration of sugarcane (Saccharum spp. hybrids) midrib segment explants

We have developed a new, simple, quick and genotype-independent method for direct regeneration of sugarcane using novel midrib segment explants. Our protocol involves two steps: the pretreatment of starting material on MS (Murashige and Skoog (1962) Physiol Plant 15:473–497) medium containing 3.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) for 8 days under continuous dark and subsequent transfer of the explants to MS medium augmented with 0.1 mg/l benzyladenine (BA) and 0.1 mg/l naphthaleneacetic acid (NAA) under light-dark conditions. On the regeneration medium, numerous globular structures appeared from the explants and subsequently differentiated into shoots. Regenerated shoots attained 2–5 cm height within 30 days of culture initiation and readily rooted on MS basal medium. Hardened plants were successfully established in the greenhouse. The regulation of sugarcane morphogenesis by auxin pretreatment is discussed.