Terminal Buds Research Articles

Thidiazuron with Mineral Oil as Alternative Bud Break Promoter for Apple Trees

Aims: This work aims to evaluate the efficiency of Revent® 500 SC (Thidiazuron) concentrations as a bud breaker promoter in apple trees, cv. Maxi Gala and Supreme Fuji, through phenology, sprouting of buds, fruit set and production per plant.
 Place and Duration of Study: The experiments were carried out in southern Brazil, municipality of Caçador / SC, during the seasons from 2017 to 2019, in the cultivars Fuji Suprema and Maxi Gala / Marubakaido / M9.
 Methodology: The treatments were 1. Control (without application); 2. Mineral Oil (MO) 3.5% + Hydrogenated Cyanamide (HC) 0.35%; 3. MO 3.5% + HC 0.5%; 4. MO 3.5% + Thidiazuron (TDZ) 0.005%; 5. MO 3.5% + TDZ 0.01%; 6. MO 3.5% + TDZ 0.015%; 7.MO 3.5% + TDZ 0.02%; 8.MO 3.5% + TDZ 0.025%, applied in stages B and C. Several variables were evaluated such as phenology, sprouting of axillary and terminal buds, fruit set, production per plant and average fruit mass.
 Results: All treatments with bud breakers advanced the phenological stages in relation to the control in the three years. In the sprouting of the axillary and terminal buds, all treatments were superior to the control. TDZ treatments showed higher sprouting of axillary buds in 2017/18 compared to standard treatments with hydrogenated cyanamide. In plant production, the treatment MO 3.5% + TDZ 0.02% was higher than the other treatments in the 2018/19 and 2019/20 seasons, in both cultivars. TDZ associated with mineral oil is efficient in inducing the sprouting of ‘Maxi Gala’ and ‘Fuji Suprema’ apple trees and can be used to recover sprouts from previous years.

Single cell transcriptome atlas of mouse mammary epithelial cells across development

BackgroundHeterogeneity within the mouse mammary epithelium and potential lineage relationships have been recently explored by single-cell RNA profiling. To further understand how cellular diversity changes during mammary ontogeny, we profiled single cells from nine different developmental stages spanning late embryogenesis, early postnatal, prepuberty, adult, mid-pregnancy, late-pregnancy, and post-involution, as well as the transcriptomes of micro-dissected terminal end buds (TEBs) and subtending ducts during puberty.MethodsThe single cell transcriptomes of 132,599 mammary epithelial cells from 9 different developmental stages were determined on the 10x Genomics Chromium platform, and integrative analyses were performed to compare specific time points.ResultsThe mammary rudiment at E18.5 closely aligned with the basal lineage, while prepubertal epithelial cells exhibited lineage segregation but to a less differentiated state than their adult counterparts. Comparison of micro-dissected TEBs versus ducts showed that luminal cells within TEBs harbored intermediate expression profiles. Ductal basal cells exhibited increased chromatin accessibility of luminal genes compared to their TEB counterparts suggesting that lineage-specific chromatin is established within the subtending ducts during puberty. An integrative analysis of five stages spanning the pregnancy cycle revealed distinct stage-specific profiles and the presence of cycling basal, mixed-lineage, and 'late' alveolar intermediates in pregnancy. Moreover, a number of intermediates were uncovered along the basal-luminal progenitor cell axis, suggesting a continuum of alveolar-restricted progenitor states.ConclusionsThis extended single cell transcriptome atlas of mouse mammary epithelial cells provides the most complete coverage for mammary epithelial cells during morphogenesis to date. Together with chromatin accessibility analysis of TEB structures, it represents a valuable framework for understanding developmental decisions within the mouse mammary gland.

Fundamental Understanding of Tea Growth and Modeling of Precise Tea Shoot Picking Based on 3-D Coordinate Instrument

Tea is a popular beverage worldwide and also has great medical value. A fundamental understanding of tea shoot growth and a precision picking model should be established to realize mechanized picking of tea shoots with a small product loss. Accordingly, the terminal bud length (Lbud), tea stem length (Lstem), terminal bud angle (αbud), tea stem angle (αstem), and growth time (t) were considered as the key growth parameters; the sum of the vertical lengths of the terminal bud and stem (ξ), the picking radius (r), and the vertical length of the stem (Zstem) were considered as the picking indexes of the tea shoots. The variations in growth parameters with time were investigated using a 3-D coordinate instrument, and the relationships between the growth parameters and the picking indexes were established using an artificial neural network (ANN). The results indicated that the tea growth cycles for periods P1, P2, P3, P4, P5, and P6 were 14, 7, 6, 4, 4, and 6 d, respectively. A growth cycle diagram of the tea growth was established. Moreover, a 5-2-12-3 ANN model was developed. The best prediction of ξ, r, and Zstem was found with 16 training epochs. The MSE value was 0.0923 × 10−4, and the R values for the training, test, and validation data were 0.99976, 0.99871, and 0.99857, respectively, indicating that the established ANN model demonstrates excellent performance in predicting the picking indexes of tea shoots.

The effects of increased exposure time to UV-B radiation on germination and seedling development of Anatolian black pine seeds.

Exhaustion of stratospheric ozone found at a height of 10-30 km around the world causes the solar UV-B (280-320 nm) radiation to penetrate through the atmosphere more, and thus to reach the Earth's surface quicker. The protective ozone layer gets damaged by human activities constantly, and the increasing levels of UV radiation present threats to all life forms, plants, animals, and even microorganisms. However, the studies conducted on the effects of UV radiation on plants, and especially forest trees, are rather limited. In this study, it was aimed to identify the effects of UV-B radiation on some germination and seedling characteristics of Anatolian black pine seeds. Within the scope of the study, seeds were exposed to UV-B radiation for 5, 10, 20, 30, 40, 50, and 60 min for germination experiments; and the germination speed (GS) was calculated as the ratio of the germinated seeds to the solid seeds at the end of the 7th day, whereas the germination percentage (GP) was calculated as the ratio of the germinated seeds to the solid seeds at the end of the 35th day. The seeds reserved for the seedling experiment were exposed to UV-B radiation for 1, 3, 5, and 7 h. With the measurements made at the end of the day, the seedling length (SL), the terminal bud length (TBL), the branch number (BN), the root collar diameter (RCD), the stem fresh weight (SFW), the root fresh weight (RFW), the stem dry weight (SDW) and the root dry weight (RDW), and the rooting percentage (RP) were determined. Variance analysis and Duncan test were applied to the obtained data with the help of SPSS package program. The study results revealed that the exposure time to increased UV-B radiation significantly affected all characters; the least affected character was RP, and that the most affected characters were RDW, SDW, and RCD. As a result of the study, it was found that even the applications with the lowest intensity took effect in most of the characters, that the seedling development decreased by more than 80% in terms of some characters at the end of 7-h application, and that even the decrease in the RP character, which was the least affected by the 7-h UV-B application, was above 50%.

Freezing stress damage and growth viability in Vaccinium macrocarpon Ait. bud structures.

After a freezing event, it can be challenging to extrapolate levels of freezing damage to plant growth viability based on the presence or absence of symptoms in specific bud tissues. This study investigated the relationship between freezing damage in terminal buds during ecodormancy and their viability during the subsequent growing season. We identified the bud structure that best explained this relationship, and developed a model to explain the changes in bud cold hardiness. Vertical shoots (uprights) of Vaccinium macrocarpon Ait. were sampled in central Wisconsin during Spring of 2018 and 2019. Sets of uprights with terminal buds were subjected to controlled freezing tests, followed by either visual freeze damage evaluation or assessment of shoot viability by growth assays. We determined the Browning Lethal‐Temperature50 (BLT50), as temperature for 50% damage (tissue browning) at each bud structure, and Growth Lethal‐Temperature50 (GLT50) temperature where 50% reduction in growth viability occurred. Two models were constructed to explain: (1) bud structure damage and growth viability, and (2) GLT50's seasonal changes, representing the cold hardiness variations, and environmental factors. The correlation between the BLT50 and GLT50 values was closest for the bud scales and bud axis, indicating the better correspondence between levels of freezing damage with the impact on the growth potential. In addition, the latter was also the most suitable candidate for modeling due to easier damage evaluation. The freezing stress damage of the bud axis explained comparatively best the resulting growth viability. Seasonal changes in GLT50 were best explained by temperature indices based on daily minimum and on maximum temperatures over 10‐day periods. However, among the model components, daily maximum temperatures had the greatest influence on V. macrocarpon cold hardiness changes during ecodormancy.

Dynamic Changes in Endogenous Hormones in Terminal Buds from Different Crown Positions in Sequoia sempervirens (Lamb.) Endl

Endogenous hormones can improve plant resistance and regulate growth and development. To obtain the basis of chemical control technology for improving Sequoia sempervirens resistance in Xuzhou, China, the current study probed the dynamic changes of endogenous hormones in terminal buds from different crown positions in S. sempervirens. Enzyme-linked immunosorbent assay (ELISA) was used to measure changes in the contents of endogenous hormones in terminal buds from the upper, middle, and lower lateral branches. The results were as follows: Indole acetic acid (IAA) in all terminal positions had a similar change trend of “rise–drop–rise.” Gibberellic acid (GA) in the upper and middle terminal buds showed similar trends of “drop–rise,” but GA in the lower lateral branches presented a “rise–drop” trend. Zeatin–riboside (ZR) in all terminal positions had similar change trends of “drop–rise.” Abscisic acid (ABA) in all terminal positions had similar change trends of “drop–rise–drop.” the trend of (IAA + GA + ZR)/ABA in all terminal positions was the same as that of IAA. Our results confirmed that, in autumn, the high content and ratio of stimulatory endogenous hormones in the terminal bud of S. sempervirens induced the terminal bud cells to continue to divide and grow, and the new branches could not be fully lignified and deeply dormant before the onset of low temperatures in winter, which led to a decrease in cold resistance and even the death of the terminal buds.

Effect of salinity and drought stress on morphological and biochemical properties of two Iranian fenugreek (Trigonella foenum-graecum) populations

In this study, micro propagation of two Iranian fenugreek populations and their morphological and biochemical responses to salinity and drought stresses in in vitro culture condition were conducted using factorial experiment in a completely randomized design in three replications. Different explant type (terminal bud, cotyledon and epicotyledon explant) were cultured in MS medium contain different concentration of plant growth regulators such as kin (0, 0.5 and 1 mg / l) and 2,4-D (0.5, 1 and 2 mg / l). Murashige and Skoog (MS) medium supplemented with 1 mg/l kinetin and 2 mg/l 2,4-D showed the highest callus proliferation rate per explants in both populations. The highest amount of callus volume was obtained from the explants of the terminal bud. Proliferated calli from terminal bud explant were green and yellowish, from cotyledon were yellowish to white with soft texture, and the cotyledons were greenish and compact. The results of salinity stresses with different concentrations of sodium chloride (0, 70 and 120 mM) and drought stress with polyethylene glycol (0, 5 and 10%) showed that both stresses decreased callus growth and increased total protein, proline, catalase, peroxidase and trigonelin content in both populations. Trigonelin measurement showed that ‘Borazjan’ papulation had higher trigonelin content, in vitro, than ‘Ardestan’ papulation.

Cul3 is required for normal development of the mammary gland.

Cullin 3 (Cul3) has recently been implicated in a multitude of different processes, including the oxidative stress response, autophagy, tumorigenesis, and differentiation. To investigate the role of Cul3 in mammary gland development, we created a mouse model system using Cre-lox targeting where Cul3 is specifically deleted from the mammary gland. Such MMTV-Cre Cul3Flx/Flx mice examined at 2 and 3 months of age show delays and defects in mammary gland development. Mammary ductal trees from Cul3-deficient mammary glands exhibit delayed forward growth through the mammary fat pad, dilation of the ducts, and abnormal morphology of some of the epithelial structures within the gland. Additionally, terminal end buds are larger and less plentiful in MMTV-Cre Cul3Flx/Flx mammary glands, and there is significantly less primary and secondary branching compared to control animals. In contrast, by 6 months of age, the mammary ductal tree has grown to fill the entire mammary fat pad in glands lacking Cul3. However, distorted epithelial structures and dilated ducts persist. MMTV-Cre Cul3Flx/Flx mothers are able to nourish their litters, but the process of involution is slightly delayed in mammary glands lacking Cul3. Therefore, we conclude that while Cul3 is not essential for mammary gland function, Cul3 is required for the mammary gland to proceed normally through development.

Role of organophosphorous pesticides and acetylcholine in breast carcinogenesis.

Breast cancer is the leading cause of cancer-related death in women worldwide. Several studies have addressed the association between cancer in humans and agricultural pesticide exposure. Evidence indicates that exposure to organophosphorous pesticides such as parathion and malathion occurs as a result of occupational factors since they are extensively used to control insects. On the other hand, estrogens have been considered beneficial to the organism; however, epidemiological studies have pointed out an increased breast cancer risk in both humans and animals. Experimental female rat mammary gland cancer models were developed after exposure to parathion, malathion, eserine, an acetylcholinesterase inhibitor, and estrogen allowing the analysis of the signs of carcinogenicity as alteration of cell proliferation, receptor expression, genomic instability, and cell metabolism in vivo and in vitro. Thus, pesticides increased proliferative ducts followed by ductal carcinoma; and 17β-estradiol increased proliferative lobules followed by lobular carcinomas. The combination of both pesticides and either eserine or estrogen induced tumors with both types of structures followed by mammary gland tumors and metastasis to the lung and kidneys after 240 days of a 5-day treatment. Studies also showed that these pesticides and eserine decreased three to five times the acetylcholinesterase activity in the serum compared to controls whereas terminal end buds increased in number, being inhibited by atropine. Genomic instability was analyzed in such tissues (mp53, CYP1A2, c-myc, c-fos, ERα, M2R) and pesticides increased protein expression that was stimulated by estrogens but inhibited by atropine. Eserine also transformed the epithelium of the rat mammary gland in the presence of estrogen and increased the number of terminal end buds after treatment inducing mammary carcinomas. Then, enzymatic digestion of such structures gave rise to cells with increased DNA synthesis and induced anchorage independence. Thus, there were changes in the epithelium of the mammary gland influencing breast carcinogenesis. Furthermore, these substances and acetylcholine also showed the signs of carcinogenicity in vitro as cell proliferation, receptor expression (ERα, ErbB2, M2R), genomic instability (c-myc, mp53, ERα, M2R), and cell metabolism. A unique cellular model is also presented here based on the use of MCF-10 F, a non-tumorigenic cell line that represents a valuable clinically translatable experimental approach that identifies mechanistic links for pesticides and estrogen as suspect human carcinogenic agents.

Local accumulation of extracellular matrix regulates global morphogenetic patterning in the developing mammary gland

The tree-like pattern of the mammary epithelium is formed during puberty through a process known as branching morphogenesis. Although mammary epithelial branching is stochastic and generates an epithelial tree with a random pattern of branches, the global orientation of the developing epithelium is predictably biased along the long axis of the gland. Here, we combine analysis of pubertal mouse mammary glands, a three-dimensional (3D)-printed engineered tissue model, and computational models of morphogenesis to investigate the origin and the dynamics of the global bias in epithelial orientation during pubertal mammary development. Confocal microscopy analysis revealed that a global bias emerges in the absence of pre-aligned networks of type I collagen in the fat pad and is maintained throughout pubertal development until the widespread formation of lateral branches. Using branching and annihilating random walk simulations, we found that the angle of bifurcation of terminal end buds (TEBs) dictates both the dynamics and the extent of the global bias in epithelial orientation. Our experimental and computational data demonstrate that a local increase in stiffness from the accumulation of extracellular matrix, which constrains the angle of bifurcation of TEBs, is sufficient to pattern the global orientation of the developing mammary epithelium. These data reveal that local mechanical properties regulate the global pattern of mammary epithelial branching and may provide new insight into the global patterning of other branched epithelia.

Cranberry response to sulfentrazone rate, timing, and application volume

AbstractThe recent registration of sulfentrazone, a selective, soil-applied, PRE herbicide labeled for control of various weeds in cranberry, expanded the number of modes of action that could be used in the crop. A 2018 preliminary study in Massachusetts showed that high rates of sulfentrazone applied at the cabbage head stage reduced the number of flowering uprights (vertical stems) without impacting the final yield. To clarify the use patterns needed to promote crop safety when using sulfentrazone, six studies were conducted in New Jersey and Massachusetts in 2019 and 2020. Studies compared sulfentrazone applications made at two timings (spring dormant, SD; or cabbage head [CH] stage), two rates (280 and 420 g ai ha−1), and three application volumes simulating either chemigation (3,740 L ha−1) or boom application (190 L ha−1 alone or followed by 0.25 cm water wash-off). Boom application studies in New Jersey in 2018 and 2019 did not show significant long-lasting injury (necrosis or stunting). However, a comprehensive observation of cranberry uprights 8 wk after treatment showed a high rate of terminal bud necrosis, a reduction in the number of reproductive structures, and the development of axillary shoots associated with a high rate of sulfentrazone applied at CH. A mitigation study conducted in 2019 and 2020 confirmed the safety of chemigated sulfentrazone at the high rate with no yield reduction, regardless of crop stage at application. Washing off the herbicide from the cranberry canopy immediately after boom application did prevent the necrosis of terminal bud and the related development of nonproductive secondary shoots. Considering the results of this study, application of sulfentrazone over the top of cranberry vine before scales of the terminal bud start loosening would be prudent practice at this time.

An Intravital Microscopy Toolbox to Study Mammary Gland Dynamics from Cellular Level to Organ Scale

The architecture of the mouse mammary gland is highly dynamic and constantly remodeled during pubertal development and estrous cycle-driven sprouting and regression of alveolar side branches. During each of these developmental stages, turnover is driven by distinct subsets of mammary epithelial cells. Extensive previous research has shed light on the unique morphological and cell biological characteristics of each stage. However, technological shortcomings failed to capture the dynamics and single-cell contributions to mammary remodeling. Here, we developed in vivo imaging strategies to follow the same mammary ducts over time and quantify the dynamics of mammary gland growth and remodeling from single-cell level to organ scale. Using a combination of intravital microscopy and genetic reporter systems we show how proliferative heterogeneity drives ductal morphogenesis during different developmental stages. To visualize pubertal growth at the cellular level, we performed long-term time-lapse imaging of extending terminal end buds through a mammary imaging window. We show that single-cells within the terminal end buds are extremely motile and continuously exchange position whilst the duct is elongating. To visualize short-term remodeling in the adult mammary gland at the single cell level, we performed multi-day intravital imaging in photoconvertible Kikume Green–Red mice and fluorescent ubiquitination-based cell cycle indicator mice. We demonstrate that the contribution of single-cells to estrous-driven remodeling is highly variable between cells in the same micro-environment. To assess the effects of this dynamic proliferative contribution on the long-term stability of tissue architecture, we developed a repeated skin flap method to assess mammary gland morphology by intravital microscopy over extended time spans for up to six months. Interestingly, in contrast to the short-term dynamic remodeling, the long-term morphology of the mammary gland remains remarkably stable. Together, our tool box of imaging strategies allows to identify and map transient and continuing dynamics of single cells to the architecture of the mammary gland.

Differences in sugarcane stool branching within Saccharum spontaneum genotypes and compared to Saccharum officinarum and commercial varieties

Commercial sugarcane varieties are hybrids between Saccharum officinarum, known for its high sucrose content but poor ratooning growth, and Saccharum spontaneum, known for its low sucrose but greater propensity to produce tillers and better disease resistance. While only 20% of the Saccharum hybrid genome originates from S. spontaneum, the genes underlying the ability to produce more tillers over successive harvests have historically been associated with this species. In order to assess the variation in stool branching and tiller recruitment, 10 genotypes were assessed, including four S. spontaneum, two S. officinarum, two recent S. spontaneum introgressed lines and 2 commercial hybrids. Differences in branching were observed amongst the S. spontaneum genotypes; while all were classified as sympodial rhizome types lacking a terminal bud, there were differences in the degree of branching and the lengths of the underground internodes, with some classified as sprawling (with seven levels of branching) and others as clumping (with four to five levels of branching) depending on the stem nodes. In contrast, the S. officinarum genotypes had limited branching, expanding to only three levels. The S. hybrids and S. spontaneum backcrosses had greater similarity to the clumping S. spontaneum genotypes than to the S. officinarum genotypes. Principal component analysis separated the genotypes of sprawling S. spontaneums, clumping S. spontaneum, hybrids/introgressed lines and S. officinarum. The variation in stool branching may be used to select S. spontaneum parents that would yield better ratooning abilities in their hybrids with S. officinarum, without the ‘weediness’ associated with sprawling rhizomes, for commercial sugarcane production.

RNAi-mediated repression of dormancy-related genes results in evergrowing apple trees

DORMANCY ASSOCIATED MADS-box (DAM) and SHORT VEGETATIVE PHASE (SVP) genes have been implicated in the regulation of winter dormancy in perennials. Ectopic expression of apple (Malus ×domestica 'Royal Gala') DAM and SVP genes delays budbreak and constrains lateral shoot outgrowth. In this study, we used RNAi interference (RNAi) to simultaneously target all apple DAM and SVP genes to study their role and mode of action in the regulation of bud dormancy, budbreak and flowering. A synthetic construct carrying a hairpin fragment assembled from sequences specific to coding regions of three DAM and two SVP genes was used to generate transgenic lines. Reduced expression of DAM/SVP genes resulted in delayed leaf senescence and abscission in autumn, failure to enter bud dormancy in winter, and continual growth of new leaves regardless of the season for over 3years. Precocious flowering but normal flower morphology, fertility and fruit development were observed. The non-dormant phenotype was associated with modified phytohormone composition. The content of gibberellins (GAs) and jasmonates (JAs) was significantly increased in terminal buds of RNAi lines compared to wildtype plants, accompanied by elevated expression of the key GA biosynthesis pathway gene GIBBERELLIN 20 OXIDASE-2 (MdGA20ox-2) along with the FLOWERING LOCUS T gene MdFT2. The key mediator of plasmodesmatal closure, MdCALLOSE SYNTHASE 1 (MdCALS1) was repressed in RNAi lines. This study provides functional evidence for the role of DAM/SVP genes in vegetative phenology of apple, and paves the way for production of low-chill varieties suitable for growth in warming climates.

Assessing and Minimizing the Development and Spread of Fire Blight Following Mechanical Thinning and Pruning in Apple Orchards.

The adoption of mechanical thinning and pruning in commercial apple orchards has been limited largely by the risk of development and spread of fire blight. This devastating disease, caused by the bacterial pathogen Erwinia amylovora, may be transmitted by mechanical injury such as pruning, especially under warm, moist conditions conducive to bacterial growth, infection, and disease development. However, risk may be mitigated by avoiding highest-risk times and applying a bactericide, such as streptomycin, after mechanical thinning or pruning. In 'Gala' and 'Idared' orchards, we evaluated the risk of fire blight development and spread after mechanical thinning early in bloom (20% bloom), when seasonal temperatures are cooler and there are few open flowers available for infection. In both orchards, we also evaluated the spread and development of fire blight by mechanical pruning in July and in August, before and after terminal bud set, when shoot growth is slowed and the tree is less susceptible to infection. We also assessed the potential efficacy of a streptomycin or Bacillus subtilis biopesticide application after mechanical thinning and pruning to mitigate the spread of fire blight. In the 'Gala' orchard, disease never developed beyond the inoculated tree after thinning or pruning, which was unexpected for this highly susceptible cultivar. In the 'Idared' orchard, incidence of blossom or shoot blight from the point source, represented as relative area under the disease progress curve, was rarely different for trees that underwent mechanical thinning or mechanical pruning compared with untreated trees, and it was often reduced or eliminated when the antibiotic streptomycin or the B. subtilis biopesticide was applied within 24 h of mechanical thinning or pruning. For both thinning and pruning, incidence of fire blight dropped off quickly beyond the inoculated tree in the 'Idared' orchard and generally was not observed in trees beyond 10 to 15 m from the inoculated point source or predicted beyond 10 m by exponential and power law models fit to the disease progress curves. The results of this work demonstrate the low risk for fire blight development and spread by mechanical thinning and pruning when practiced under low-risk conditions-early in bloom for mechanical thinning and after terminal bud set (in August) for mechanical pruning-especially when paired with a subsequent bactericide application. This study demonstrates the safe use of mechanical thinning and pruning in commercial apple production, corroborated by anecdotal evidence from apple growers in western New York State.

The Role of Csmd1 during Mammary Gland Development

The Cub Sushi Multiple Domains-1 (CSMD1) protein is a tumour suppressor which has been shown to play a role in regulating human mammary duct development in vitro. CSMD1 knockdown in vitro demonstrated increased cell proliferation, invasion and motility. However, the role of Csmd1 in vivo is poorly characterised when it comes to ductal development and is therefore an area which warrants further exploration. In this study a Csmd1 knockout (KO) mouse model was used to identify the role of Csmd1 in regulating mammary gland development during puberty. Changes in duct development and protein expression patterns were analysed by immunohistochemistry. This study identified increased ductal development during the early stages of puberty in the KO mice, characterised by increased ductal area and terminal end bud number at 6 weeks. Furthermore, increased expression of various proteins (Stat1, Fak, Akt, Slug/Snail and Progesterone receptor) was shown at 4 weeks in the KO mice, followed by lower expression levels from 6 weeks in the KO mice compared to the wild type mice. This study identifies a novel role for Csmd1 in mammary gland development, with Csmd1 KO causing significantly more rapid mammary gland development, suggesting an earlier adult mammary gland formation.

Histological Findings of Mammary Gland Development and Risk of Breast Cancer in BRCA1 Mutant Mouse Models.

PurposeThe breast cancer susceptibility gene, BRCA1, is involved in normal development and carcinogenesis of mammary glands. Here, we aimed to evaluate the relationship between histological findings of mammary gland development and breast cancer risk in BRCA1 mutant mice.MethodsFive BRCA1 mutant mice and five non-mutant FVB/NJ mice were used for each group of 1-month-old (pubertal), 3-month-old (fertile), and 8-month-old (menopausal) mice. In another experiment, 15 BRCA1 mutant mice were followed up to 8 months after birth and classified into tumor-bearing (11 mice) and tumor-free (4 mice) groups. Excised mammary gland tissues were stained with Carmine Alum, and the number of terminal end buds (or alveolar buds), branching density, and duct elongation were measured using image analysis programs. Differences between the two groups were assessed using paired t-test.ResultsOne-month-old BRCA1 mutant mice showed a higher number of terminal end buds (23.8 ± 1.0 vs. 15.6 ± 0.8, p = 0.0002), branching density (11.7 ± 0.4 vs. 9.6 ± 0.5%, p = 0.0082), and duct elongation (9.7 ± 0.7 vs. 7.3 ± 0.4 mm, p = 0.0186) than controls. However, there was no difference between the 3- and 8-month-old groups. In BRCA1 mutant mice, the tumor-bearing group showed a significantly higher number of alveolar buds (142.7 ± 5.5 vs. 105.5 ± 5.4, p = 0.0008) and branching density (30.0 ± 1.0 vs. 24.1 ± 1.1%, p = 0.008) than the tumor-free group; however, duct elongation was not different (23.9 ± 0.6 vs. 23.6 ± 0.6 mm, p = 0.8099) between the groups.ConclusionBRCA1 mutant mice exhibited early pubertal mammary gland development and delayed age-related mammary gland involution was associated with breast cancer. Our results may have clinical implications for predicting breast cancer risk and developing prevention strategies for BRCA1 mutation carriers.

Adaptive performance of genetically improved and unimproved seedlings of Scots pine

Our main objective was to determine whether various genetically improved reproductive materials of Scots pine ( L.) differ in growth rhythm, autumn cold acclimation and resilience from unimproved materials. The study consisted of two successive indoor experiments with Scots pine seedlings representing four levels of genetic gain (unimproved natural stands, first-generation seed orchards, 1.5-generation seed orchards and seed orchards established with freezing-tested parents) and a wide range of geographical origins within Finland. The seedlings were assessed for terminal shoot elongation, growth cessation, bud set, freezing injuries and bud flushing over the first growth period. All the adaptive traits showed a latitudinal trend regardless of the genetic level. Seed orchard progenies and natural stand progenies did not differ significantly in the timing of growth cessation, bud set, and the flushing rate of the frost-injured seedlings, after the trait variation was adjusted to the latitude of origin. The differences in autumn frost hardiness were insignificant, too, except for the somewhat higher injury rate displayed by the first-generation seed orchard materials. The finding was not conclusive due to ambiguous results from the two experiments. Overall, we did not find evidence of alarming compromises in the adaptive performance of genetically improved materials.Pinus sylvestris

Reapplication of bud break promoters in ‘Fuji Suprema’ apple trees

Abstract The aim of this work was to verify the effectiveness of the reapplication of bud break producers on flowering, sprouting and production of ‘Fuji Suprema’ apple trees. The experiment was carried out in an experimental orchard located in the municipality of Caçador, SC, during 2016/2017 to 2019/2020 seasons. Treatments were applied at stages B and C, and those with reapplication, from 7 to 14 days after the first application. Phenology, axillary and terminal bud break, frui set, production per plant and average fruit mass were evaluated. Phenology was advanced in relation to control with the application of bud break promoters. However, treatments applied at stage B provided greater advance in relation to applications at stage C. In axillary and terminal bud break, all treatments were superior to control. In some seasons, the sequential application of bud break promoters increased bud sprouting compared to single application treatment. There is no reduction fruit set in treatments with sequential application in relation to single application. In plant production, sequential applications did not differ from single application. The average fruit mass was not altered by the sequential application of bud break promoters.

Infestación, daño y enemigos naturales de Heteropsylla texana en algarrobo (Prosopis sp.) en Tongorrape (Motupe - Lambayeque)

Algarrobo trees, Prosopis sp., were assessed at Tongorrape forest (Motupe-Lambayeque) in order to know infestation and damages levels of Heteropsylla texana Crawford, and natural enemies of the pest. Assessments, 10 in total, were carried out each 15 days from march to july, 2014. Algarrobo trees were selected taking on account similarity in height, age and foliage density. Infestation was evaluated with a scale from grade 0 to 5 on five terminal buds per tree. On each tree, by sight, foliage damage intensity was determined under a scale from grade 0 to 5. Terminal buds were conditioned on plastic jars to carry them to an insect recovery laboratory. Insect identification was carried out at La Molina-Lima SENASA entomological museum. Infestation varied from grade 1 to 3, which means that psilid population level was from low to moderate, while damage intensity varied from 2 to 3 grade, which means important damage on trees foliage. Paraneda pallidula gutticolis and Leucochrysa sp., were registered as important predators.