Terminal Buds Research Articles

Sporophyte Biomorphology of Athyrium Species in the Various Environmental Conditions of South Siberia

The aim of this work is to present biomorphological characteristics of ferns of the genus Athyrium Roth in southern Siberia and identify changes in the sporophyte life form during ontogenesis and in individuals of the same biological age in various ecological and coenotic conditions. The most important thing when identifying the life form of fern sporophytes is studying the formation of its perennial part—the rhizome. We define the life form of Athyrium species of southern Siberia as summer green polycyclic densely rosette ferns with monopodial–dichotomously growing underground–aboveground rhizomes and monomorphous homoiohydric fronds. It is represented by two variants: (1) large-rhizome orthotropic weakly branching vegetatively non-growing monocentric ferns (Athyrium filix-femina (L.) Roth. and A. monomachii Komarov, and A. sinense Rupr.) and (2) large-rhizome ascending weakly branching and weakly vegetatively growing monocentric or implicit-polycentric ferns (A. distentifolium Tausch ex Opiz). Neither variants allow vegetative propagation or vegetative self-maintenance of the population. Our study shows that during sporophyte ontogenesis the sizes of rhizomes and fronds increase and the branching ability of rhizomes is implemented. The branching is dichotomous: the daughter branches are formed inside the terminal bud of the maternal branch and become distinguishable only after several years. It has been determined that rhizome remains uniaxial throughout its entire life in sporophytes with low vitality, whereas the rhizomes of the sporophytes with high vitality usually branch out. Rhizome branching starts in young spore-bearing sporophytes. The largest number of branches of the rhizome and, consequently, rosettes of fronds is typical for middle-aged spore-bearing sporophytes. At the end of the life of the sporophytes with branched rhizomes, non-specialized disintegration (senile partitioning) occurs. It is expressed in the disintegration of the rhizome into the separate branches. According to the results of a study in various phytocoenoses of Kuznetsk Alatau, the intensity of rhizome branching in sporophytes of the same ontogenetic stage depends on environmental conditions: the rhizomes of A. filix-femina produce a larger number of branches in more light mixed forests (fir–aspen and fir–birch); in A. distentifolium, the intensity of the rhizome branching increases from the forest zone to the subalpine one.

Role of Dormant Buds in Crown Architecture in Coniferous and Deciduous Trees of the Temperate Zone

The goal of this study is to investigate the localization of dormant buds and the features of the structures arising from the buds in coniferous and deciduous trees in response to age-related changes and various growing conditions. The crown is analyzed using architectural models and the reiteration concept. It is found that the dormant buds in deciduous trees are usually at the bases of annual growth. The dormant buds in conifers are at the bases of annual growth, in the axils of bud scales, or along the entire length of the shoot in the axils of needles and in the shoot distal part. It is revealed that the terminal buds of short shoots can function as dormant buds. The natural aging of skeletal axes is an endogenous factor of the development of shoots from dormant buds in deciduous trees. In evergreen conifers, it is the plant’s response to needle aging. This leads to the induction of the growth of dormant buds and to the acropetal appearance of the buds on the mother axis in conifers. The reiterated complexes of deciduous trees form in response to the completion of the axis development cycle, which initiates dormant buds in the centripetal direction. The reiterated complexes of conifers look like bundles: such structures form due to the easy initiation of dormant buds, which leads to the formation of the shoots of other orders. The reiterated complexes of deciduous trees are characterized by prolonged growth, acrotonicic branching, and orthotropic growth direction. The crown of the old generative and senile deciduous trees consists almost entirely of reiterated complexes. It has been found that conifers have a different degree of participation of dormant buds in the crown formation, which can vary significantly within the same genus. The reiterated complexes of Picea abies (L.) Karst. replace small twigs. In some other species (for example, Picea schrenkiana Fisch. et E. Mey., Abies sibirica Ledeb., Pinussibirica Du Tour.), the reiterated complexes can also replace the skeletal branches extending from the trunk. No secondary crown is formed in Pinus sylvestris L.

In Utero Exposure to Bisphenol a Promotes Mammary Tumor Risk in MMTV-Erbb2 Transgenic Mice Through the Induction of ER-erbB2 Crosstalk.

Bisphenol A (BPA) is the most common environmental endocrine disrupting chemical. Studies suggest a link between perinatal BPA exposure and increased breast cancer risk, but the underlying mechanisms remain unclear. This study aims to investigate the effects of in utero BPA exposure on mammary tumorigenesis in MMTV-erbB2 transgenic mice. Pregnant mice were subcutaneously injected with BPA (0, 50, 500 ng/kg and 250 µg/kg BW) daily between gestational days 11–19. Female offspring were examined for mammary tumorigenesis, puberty onset, mammary morphogenesis, and signaling in ER and erbB2 pathways. In utero exposure to low dose BPA (500 ng/kg) induced mammary tumorigenesis, earlier puberty onset, increased terminal end buds, and prolonged estrus phase, which was accompanied by proliferative mammary morphogenesis. CD24/49f-based FACS analysis showed that in utero exposure to 500 ng/kg BPA induced expansion of luminal and basal/myoepithelial cell subpopulations at PND 35. Molecular analysis of mammary tissues at PND 70 showed that in utero exposure to low doses of BPA induced upregulation of ERα, p-ERα, cyclin D1, and c-myc, concurrent activation of erbB2, EGFR, erbB-3, Erk1/2, and Akt, and upregulation of growth factors/ligands. Our results demonstrate that in utero exposure to low dose BPA promotes mammary tumorigenesis in MMTV-erbB2 mice through induction of ER-erbB2 crosstalk and mammary epithelial reprogramming, which advance our understanding of the mechanism associated with in utero exposure to BPA-induced breast cancer risk. The studies also support using MMTV-erbB2 mouse model for relevant studies.

Infant Formula Feeding Changes the Proliferative Status in Piglet Neonatal Mammary Glands Independently of Estrogen Signaling

Background:Soy infant formula contains isoflavones, which are able to bind to and activate estrogen receptor (ER) pathways. The mammary gland is sensitive to estrogens, raising concern that the use of soy formulas may promote premature development. Objective:We aimed to determine if soy formula feeding increases mammary gland proliferation and differentiation in comparison to other infant postnatal diets. Methods:White-Dutch Landrace piglets aged 2 d received either sow milk (Sow), or were provided milk formula (Milk), soy formula (Soy), milk formula supplemented with 17-beta-estradiol (2 mg/(kgd); M + E2), or milk formula supplemented with genistein (84 mg/L of diet; M + G) until day 21. Mammary gland proliferation and differentiation was assessed by histology, and real-time RT-PCR confirmation of differentially expressed genes identified by microarray analysis. Results:Mammary terminal end bud numbers were 19–31% greater in the Milk, Soy, and M+G groups relative to the Sow and M+E2, P <0.05. Microarray analysis identified differentially expressed genes between each formula-fed group relative to the Sow (±1.7-fold, P <0.05). Real-time RT-PCR confirmed 2- to 4-fold increases in mRNA transcripts of genes involved in cell proliferation, insulin-like growth factor 1 (IGF1), fibroblast growth factor 10 (FGF10), and fibroblast growth factor 18 (FGF18), in all groups relative to the Sow, P <0.05. In contrast, genes involved in cell differentiation and ductal morphogenesis, angiotensin II receptor type 2 (AGTR2), microtubule associated protein 1b (MAP1B), and kinesin family member 26b (KIF26B), were significantly upregulated by 2-, 4-, and 13-fold, respectively, in the M+E2 group. Additionally, mRNA expression of ER-specific gene targets, progesterone receptor (PGR), was increased by 12-fold, and amphiregulin (AREG) and Ras-like estrogen regulated growth inhibitor (RERG) expression by 1.5-fold in the M+E2 group, P <0.05. In the soy and M+G groups, mRNA expressions of fatty acid synthesis genes were increased 2- to 4-fold. Conclusions:Our data indicate soy formula feeding does not promote ER-signaling in the piglet mammary gland. Infant formula feeding (milk- or soy-based) may initiate proliferative pathways independently of estrogenic signaling.

Freezing stress survival mechanisms in Vaccinium macrocarpon Ait. terminal buds.

Plants' mechanisms for surviving freezing stresses are essential adaptations that allow their existence in environments with extreme winter temperatures. Although it is known that Vaccinium macrocarpon Ait. buds can acclimate in fall and survive very cold temperatures during the winter, the mechanism for survival of these buds is not known. The main objective of this study was to determine which of the two major mechanisms of freezing stress survival, namely, deep supercooling or freeze-induced dehydration, are employed by V. macrocarpon terminal buds. In the present study, no low-temperature exotherms (LTEs) were detected by differential thermal analysis. Furthermore, a gradual reduction of relative liquid water content in the inner portions of buds during magnetic resonance imaging (MRI) scans performed between 0 and -20°C (where no damage was detected in controlled freezing tests (CFT)) indicates these buds may not deep supercool. The higher ice nucleation activity of outer bud scales and the appearance of large voids in this structure in early winter, in conjunction with the MRI observations, are evidence supportive of a freeze-induced dehydration process. In addition, the presence of tissue browning in acclimated buds as a result of freezing stress was only observed in CFT at temperatures below -20°C, and this damage gradually increased as test temperatures decreased and at different rates depending on the bud structure. Ours is the first study to collect multiple lines of evidence to suggest that V. macrocarpon terminal buds survive long periods of freezing stress by freeze-induced dehydration. Our results provide a framework for future studies of cold hardiness dynamics for V. macrocarpon and other woody perennial species and for the screening of breeding populations for freezing stress tolerance traits.

Differential effects of the 1,25D3-MARRS receptor (ERp57/PDIA3) on murine mammary gland development depend on the vitamin D3 dose

1,25 dihydroxyvitamin D3 (1,25D3) is the most potent biologically active form of vitamin D3. Its actions on the mammary gland include cell growth inhibition and anti-cancer effects. This study’s purpose was to explore the role of the 1,25D3-membrane associated rapid response steroid (MARRS) receptor in the mammary gland using a tissue-specific knockout mouse model and a vitamin D3 dietary intervention. Three genotype groups were created using the Cre/loxp system to knock-down (+/−) and knockout (−/−) the MARRS receptor in epithelial cells of mammary glands (MG). Abdominal MGs were collected from 6-week old female mice (n = 94) on diets of 10,000 IU/kg (excess), 1,000 IU/kg (sufficient) or 0 IU/kg (deficient) of D3. There was a significant interaction between genotype and diet regarding number of terminal end buds (TEBs) (p = 0.001) and ductal coverage of the fat pad (p = 0.03). MARRS -/- mice on the sufficient diet had significantly fewer TEBs (p = 0.001) compared to MARRS +/+ on the same diet, but the opposite effect was seen in mice on the excess diet. There were no effects of genotype on TEBs when animals were vitamin D3 deficient. These results suggest that there is an effect of MARRS on mammary gland development that is dependent on 25(OH)D status, specifically, altering the number of highly proliferative TEBs. Increased numbers of TEBs have been correlated with increased breast cancer risk later in life. Therefore the results of this study warrant further examination of 25(OH)D status and recommendations in adolescent humans to reduce dietary effects on future breast cancer risk.

Integrin Binding Dynamics Modulate Ligand-Specific Mechanosensing in Mammary Gland Fibroblasts.

SummaryThe link between integrin activity regulation and cellular mechanosensing of tissue rigidity, especially on different extracellular matrix ligands, remains poorly understood. Here, we find that primary mouse mammary gland stromal fibroblasts (MSFs) are able to spread efficiently, generate high forces, and display nuclear YAP on soft collagen-coated substrates, resembling the soft mammary gland tissue. We describe that loss of the integrin inhibitor, SHARPIN, impedes MSF spreading specifically on soft type I collagen but not on fibronectin. Through quantitative experiments and computational modeling, we find that SHARPIN-deficient MSFs display faster force-induced unbinding of adhesions from collagen-coated beads. Faster unbinding, in turn, impairs force transmission in these cells, particularly, at the stiffness optimum observed for wild-type cells. Mechanistically, we link the impaired mechanotransduction of SHARPIN-deficient cells on collagen to reduced levels of collagen-binding integrin α11β1. Thus integrin activity regulation and α11β1 play a role in collagen-specific mechanosensing in MSFs.

Recovery of Cryopreserved Buds of Chinese Yam (Dioscorea Polystachya Turcz.) Observed under Scanning Electron Microscope (Sem)

Early development of cryopreserved Chinese yams’ (Dioscorea polystachya Turcz) explants were studied under scanning electron microscope (SEM). A combination of vitrification and droplet protocol was implemented with 3 weeks cold acclimation in an alternating temperature of 28°Cday/5°C night and 15% sucrose in the pre-culture medium. Survival in the form of shoot and swelling at the axil or at the near apex of original leaf bud was observed at 3 days after re-culture (rewarming). At 7 days after re-culture, development of new axillary shoot, elongation and enlargement of the surviving green structures as well as addition of new tissues to the previously developed callus at terminal bud were observed. Shoot differentiation from green structures was observed at 16 days after re-culture.

Environment, Photosynthesis, and Adventitious Rooting of Manchurian Lilac Cuttings Propagated in Overhead Mist, Submist, and Combination Systems

We propagated manchurian lilac (Syringa pubescens subsp. patula ‘Miss Kim’) vegetatively from stem cuttings using overhead mist, submist, and combination propagation systems. Cuttings were collected when terminal buds were already set, after the period of tender growth that is optimal for lilac propagation. Net photosynthesis (Pn) was recorded to assess whether differences in rooting could be attributed to differences in photosynthetic activity of cuttings within each system. The propagation environment differed significantly among systems, with vapor pressure deficit (VPD) substantially greater for submist systems than for overhead mist or combination systems, and root zones warmer in submist and combination systems than in overhead mist. Pn of cuttings did not differ among systems and was initially low, but increased about when the first root primordia were visible. Rooting percentages were 90% among cuttings in the combination system, with cuttings in overhead mist and submist rooting at lower, but similar, percentages (68% and 62%, respectively). Cuttings in the combination and submist systems produced significantly more and longer roots than those in the overhead mist system, and retained nearly all of their leaves. Overall, the use of systems that provide intermittent mist to the basal end of each cutting was effective for propagating manchurian lilac. Our results demonstrate that cuttings in submist alone experience a much greater VPD than those in overhead mist, but may nonetheless root at comparable percentages and produce superior measures of root system quality. Combination systems show promise for rooting of species like manchurian lilac, because cuttings rooted at high percentages and with consistent root system quality, despite having been collected after the optimal spring period for lilac propagation.

In Vitro Rhizogenesis of The Lavandula angustifolia Cultivars

In production, shoot cuttings of lavender are most often used for vegetative propagation, however, this method does not promote high propagation rate. The most effective method is propagation by axillary or terminal buds that requires further plant rooting in vitro. Due to, objective of our work was analysis of lavender in vitro rhizogenesis. Investigation was performed on Lavandula angustifolia cultivars with different concentration of the growth regulators in medium. After18 Day, Only 1 mg/l NAA did not stimulate rhizogenesis for ‘Record’ and ‘Sineva’ cultivars. Root primordia formed from the cambium cells. Further root growth accompanied by cleavage of the core tissues and they appeared on the shoot surface. Morphologically, a root cap, meristem, elongation zone and zone with root hairs were identified in de novo formed root in vitro. Along with normally roots, the appearance of roots accreted along their periphery with free apexes and roots with the decreased meristem was also noted. For ‘Prima’ cultivar, highest values of the mitotic index were observed on the hormone-free half-strength MS medium and on ½MS medium with 1.0 mg/l NAA. Thus, our data showed that root morphogenesis for lavender cultivars depended on the plant material and culture medium.

The Effect of Suckercide Product and Application Rate on Chemical Topping of Burley Tobacco

The act of topping tobacco (Nicotiana tabacum L.) involves the removal of the terminal bud or inflorescence of the tobacco plant. This practice ordinarily is accomplished by manually removing the top of each tobacco plant in an entire field, which is labor intensive and costly. The major objectives for this research were to determine which labeled suckercides could be used effectively for chemical topping of burley tobacco and the effect of suckercide rate on sucker control, yield, leaf quality, maleic hydrazide (MH) residues, and leaf chemistry. A study was initiated at Murray, Princeton, and Lexington, KY that investigated the efficacy of suckercide applications using combinations of MH, butralin, and fatty alcohols (FA). The terminal bud was not well controlled with FA or butralin alone, nor was adequate sucker control or total yield achieved. A significant reduction in total yield and sucker control were observed when plants were chemically topped with MH alone compared to manually topped or chemically topped with a tank mixture of MH and butralin at Princeton only. At the other locations, all chemically topped plants had similar yield to manually topped plants. Our data suggested that chemical topping of burley tobacco with a tank mixture of MH and a local systemic can be an acceptable alternative to manual topping as total yield and leaf quality grade index were not significantly different at any location. Total tobacco-specific nitrosamine (TSNA) content and MH residues were significantly lower with chemical topping treatments in some years and locations.

Foxp3 heterozygosity does not overtly affect mammary gland development during puberty or the oestrous cycle in mice.

Female mice heterozygous for a genetic mutation in transcription factor forkhead box p3 (Foxp3) spontaneously develop mammary cancers; however, the underlying mechanism is not well understood. We hypothesised that increased cancer susceptibility is associated with an underlying perturbation in mammary gland development. The role of Foxp3 in mammary ductal morphogenesis was investigated in heterozygous Foxp3Sf/+ and wildtype Foxp3+/+ mice during puberty and at specific stages of the oestrous cycle. No differences in mammary ductal branching morphogenesis, terminal end bud formation or ductal elongation were observed in pubertal Foxp3Sf/+ mice compared with Foxp3+/+ mice. During adulthood, all mice underwent normal regular oestrous cycles. No differences in epithelial branching morphology were detected in mammary glands from mice at the oestrus, metoestrus, dioestrus and pro-oestrus stages of the cycle. Furthermore, abundance of Foxp3 mRNA and protein in the mammary gland and lymph nodes was not altered in Foxp3Sf/+ mice compared with Foxp3+/+ mice. These studies suggest that Foxp3 heterozygosity does not overtly affect mammary gland development during puberty or the oestrous cycle. Further studies are required to dissect the underlying mechanisms of increased mammary cancer susceptibility in Foxp3Sf/+ heterozygous mice and the function of this transcription factor in normal mammary gland development.

МЕТАМЕРНАЯ ИЗМЕНЧИВОСТЬ ДЛИНЫ МЕЖДОУЗЛИЙ SALIX TRIANDRA (SALICACEAE)

The article presents the praxeological characteristics of the three-stalked willow (Salix triandra, genus Salix, family Salicaceae). Object: inbred model population of S. triandra. Material: annual shoots obtained on the same seedlings in different years from vegetative buds of different localization. Methods: comparative morphological, chronobiological, ontogenetic, analysis of the series of dynamics. Purpose: to describe and analyze the patterns of ontogenetic variability of the length of internodes on annual shoots. Results. The general variability of the length of internodes is determined, first of all, by their intra-shoot variability. Interannual differences in the length of internodes on shoots of two- and three-year-old seedlings are determined, first of all, by differences in the lower third of the shoots. No significant intracrown differences in the length of internodes were found on shoots of one year. The periodicity of the metameric dynamics of the length of internodes has been established. The interannual specificity of the series of metameric variability of the length of internodes is associated with the age of root-butt systems. The metameric variability of the length of internodes with different reliability is approximated by linear regression equations. Rhythm in metameric variability of deviations of internode length from linear trends was revealed. The graphs of the series of deviations in the length of internodes from linear trends are presented in two versions - either with two or with three peaks, which indicates the discreteness of the trajectories of shoot morphogenesis. The revealed bivariance of the trajectories of shoot morphogenesis is associated with different ages of perennial root-butt systems. Discussion and conclusions. The bivariance of shoot morphogenesis is not directly related to adaptations to environmental conditions and is determined not by genetic differences, but by epigenetic mechanisms. Hypothesis: the most probable reason for the bivariate morphogenesis of shoots is the ontogenetic heterogeneity of vegetative buds from which these shoots develop. To verify the hypothesis put forward, an experiment was proposed to study the metameric variability of the length of internodes of shoots obtained from terminal and axillary buds in the same year.

Potassium fertilization in bareroot nurseries in the southern US: a review

This review covers most of the published literature on potassium (K) fertilization in bareroot seedbeds with the intent to concentrate on the southern United States. The timing and rates of K fertilization for bareroot seedlings are often based on logic and myths and, as a result, K recommendations vary considerably. Some recommend bareroot pine seedlings be fertilized with twice as much K as nitrogen (N) while others apply less than 100 kg ha-1. It was determined that several long-held claims about K fertilization are invalid. Nursery seedbeds do not need to contain four times as much available K as N and the belief that extra K fertilization will increase freeze tolerance or drought resistance of non-deficient seedlings is invalid. There are no data to support the claim that K fertilization increases root growth or assists in the formation of terminal buds. For sandy seedbeds, there is no need to apply K before sowing. Adding extra K during the fall does not increase seedling morphology or seedling performance when loblolly pine seedlings, at lifting, have more than 0.5% K in needles. A reduction of K fertilization can be achieved by reviewing foliar tests prior to K top-dressings.

Neosilba Perezi (Romero &amp; Ruppel, 1973) (Diptera: Lonchaeidae) Damage Simulation on the Production of Stem Cuttings and the Productive Aspects of Cassava

The loss caused by the shoot-fly (Neosilba perezi) was simulated through the elimination of the cassava`s terminal buds, with the objective to quantify this effect towards the roots productivity, flour production and propagative material production (stem cuts). The experimental design was random blocks, with three repetitions, in a factorial scheme with an additional treatment (10 &amp;times; 4 + 1). Ten damage levels (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%) were studied, including a witness treatment (0%). The cassavas were treated during each of the four seasons of the year. The studied variables were: root productivity (t ha-1), flour production (t ha-1) and number of stem cuttings with a diameter greater than 20 and 25 mm. The induced damage in the cassava`s meristem did not significantly affect the root, nor the flour production. However, the stem cuttings production demonstrated a linear decrease in relation to the apical meristem damage level.

Effect of a Late Spring Application of Hydrogen Cyanamide on High-Chill Peaches

Due to a record low chilling accumulation in the winter of 2016–2017, many high-chill peach cultivars displayed almost no budbreak by mid-April of 2017 in central Georgia, USA, where budbreak usually occurs around mid-March. In this study, nine of these peach cultivars were used to study the effect of a late spring Dormex spray application (April 13, 2017) on subsequent budbreak, year-end cumulative vegetative growth, and following-season yield. Dormex was found to have strong stimulating effects on lateral budbreak, but little effect on terminal and floral budbreak. It also had apparent phytotoxic effects on lateral, terminal and floral buds, and growth. The effects varied among genotypes, tree ages, and shoot types. The peak of the effects occurred two weeks post-application. Most floral buds abscised before they swelled. Between Dormex-sprayed trees and unsprayed controls, there was no significant difference in the number and average length of the new lateral shoots by the end of 2017, nor in the number and weight of the fruit harvested in 2018. In conclusion, our data showed a late spring Dormex spray application stimulated earlier lateral budbreak and caused some level of phytotoxicity to all types of buds and new growth, but had little impact on flower budbreak, fruit set, year-end vegetative growth, or following-season yield. These findings provide useful information for growers, considering the need for spraying dormancy-breaking compounds when faced with insufficient chilling.

Epithelial-adipocyte interactions are required for mammary gland development, but not for milk production or fertility

To investigate the role of adipose tissue in reproductive function and mammary gland development and function, we have examined lipodystrophic (LD) mice. LD mice of both sexes are sterile, but fertility can be restored with leptin injections. Mammary glands from lipodystrophic mice were rudimentary and lacked terminal end buds. Leptin-injected LD mice were able to become pregnant, showed normal pregnancy-associated glandular proliferation despite a smaller glandular area, were able to produce a small amount of milk that had grossly normal content of milk proteins and neutral lipids, but could not sustain pups to weaning. In order to separate the individual requirements for 1) adipokines such as leptin, 2) estradiol, and 3) physical epithelial-adipocyte interactions, we performed a series of experiments with both lipodystrophic mice and ob (obese mice with a mutation in the lep gene encoding the adipokine leptin) mice that received either estradiol treatment or preadipocyte transplant. The resulting fat pad did not rescue the defect in mammary gland development in lipodystrophic mice. The defect also could not be rescued with estradiol pellets. Ob/ob mice, like LD mice, lack leptin and estradiol, but retain adipose tissue. Ob mice have defective mammary gland development. However, in striking contrast to what was observed in lipodystrophic mice, reconstitution of a WT fat pad in ob mice rescued the defect in mammary gland development. Estradiol treatment did not rescue mammary gland development in ob mice. Therefore direct interaction between mammary gland epithelia and adipocytes is a requirement for full invasion and expansion of the gland, but is not required for glandular proliferation during pregnancy and milk production.

Knockout model reveals the role of Nischarin in mammary gland development, breast tumorigenesis and response to metformin treatment

Previously, our lab discovered the protein Nischarin and uncovered its role in regulating cell migration and invasion via its interactions with several proteins. We subsequently described a role for Nischarin in breast cancer, in which it is frequently underexpressed. To characterize Nischarin's role in breast tumorigenesis and mammary gland development more completely, we deleted a critical region of the Nisch gene (exons 7-10) from the mouse genome and observed the effects. Mammary glands in mutant animals showed delayed terminal end bud formation but did not develop breast tumors spontaneously. Therefore, we interbred the animals with transgenic mice expressing the mouse mammary tumor virus-polyoma middle T-antigen (MMTV-PyMT) oncogene. The MMTV-PyMT mammary glands lacking Nischarin showed increased hyperplasia compared to wild-type animal tissues. Furthermore, we observed significantly increased tumor growth and metastasis in Nischarin mutant animals. Surprisingly, Nischarin deletion decreased activity of AMPK and subsequently its downstream effectors. Given this finding, we treated these animals with metformin, which enhances AMPK activity. Here, we show for the first time, metformin activates AMPK signaling and inhibits tumor growth of Nischarin lacking PyMT tumors suggesting a potential use for metformin as a cancer therapeutic, particularly in the case of Nischarin-deficient breast cancers.

Morphological, anatomical, physiological, and cytological studies in diploid and tetraploid plants of Ispaghul (Plantago ovata Forsk.)

Ispaghul (Plantago ovata Forsk.) as an important medicinal plant has obtained a remarkable reputation due to therapeutic applications of seed mucilage. To determine the effect of in vitro-induced polyploidy on various characteristics of P. ovata, the terminal bud of two true leaves seedlings were separately treated with colchicine [0.1, 0.3 and 0.5% (w/v) for 6, 12 and 24 h] and trifluralin [7.5, 15 and 22.5% (w/v) for 24, 48 and 72 h] solutions. The ploidy level of induced tetraploids was determined via chromosome counting of root tip cells, and then confirmed through flow-cytometric analysis. Comparison the morphological, physiological, anatomical features of intact diploids and induced tetraploids revealed that tetraploids had considerable more height, thicker leaf, larger spike and seed, larger pollen grain and more seeds per spike. Moreover, the amount of chlorophyll (a, b, and total) and carotenoids, as well as chloroplast number in guard cells was further in tetraploids than diploids. Unlike density, stomata size in tetraploids was bigger than that one in diploids. It was also observed that seeds of tetraploids had more mucilage than diploids. In summary, we firstly developed the P. ovata tetraploids and suggested 0.3% colchicine for 24 h and 22.5% trifluralin for 72 h as the optimum treatments for inducing tetraploidy in P. ovata.

The first detection of the olive leaf moth Palpita vitrealis (Rossi) (Lepidoptera: Pyralidae) as a serious pest in Biskra province (Algeria)

In Algeria, little is known about the jasmine moth Palpita vitrealis (Rossi) [synonym Palpita unionalis (Hubner)]. It was not previously considered to have significant economic impacts on olives. However, during 2018, in several localities in Biskra province, Algeria, damage caused by larvae feeding on terminal buds, young leaves and shoots attracted the attention of farmers and researchers. In this province, this is the first time that P. vitrealis has been reported as a pest associated with olive trees. A morphological description of this species is given, as well as information on the symptoms and damage that have been observed.