Different concentrations of N6-benzylaminopurine (BAP) and indole acetic acid (IAA) in Murashige and Skoog based medium were assessed for their effects on shoot multiplication, nodule-like meristem proliferation and plant regeneration of the Malaysian banana cultivars Pisang Mas, Pisang Nangka, Pisang Berangan and Pisang Awak. BAP at 1-14 mg L-1 with or without 0.2 mg L-1 IAA, or BAP at 7-14 mg L-1with the same concentration of IAA, was evaluated for shoot multiplication from shoot tips and the proliferation of nodule-like meristems from scalps, respectively. Plant regeneration from scalps was assessed using 1 mg L-1BAP and 0.2 mg L-1 IAA separately, or a combination of these two growth regulators. Data on shoot multiplication, the proliferation of nodule-like meristems with associated plant regeneration were recorded after 30 days of culture. A maximum of 5 shoots per original shoot tip was achieved on medium supplemented with BAP at 5 mg L-1 (Pisang Nangka), 6 mg L-1(Pisang Mas and Pisang Berangan), or 7 mg L-1 (Pisang Awak), with 0.2 mg L-1 IAA. BAP at 11 mg L-1 with 0.2 mg L-1 IAA induced the most highly proliferating nodule-like meristems in the four banana cultivars. Plant regeneration from scalps was optimum in all cases on medium containing 1 mg L-1 BAP and 0.2 mg L-1 IAA. This is the first report on the successful induction of highly proliferating nodule-like meristems and plant regeneration from scalps of the Malaysian banana cultivars Pisang Mas, Pisang Nangka, Pisang Berangan and Pisang Awak.
The study was conducted to evaluate the root, shoot and leaf callus cell regeneration and its biochemical properties like antioxidant, carbohydrate, pigment and mineral content from broccoli root, shoot and leaf cutting in vitro. An in vitro factorial experiment was carried out based on a Completely Randomized Design (CRD) with 5 replicates in tissue culture applying different IBA (0.25, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 mg/l) and BAP (1 mg/l) concentrations using broccoli root tip and leaf cutting. The results showed that a higher callus weight was found in the cultured leaf cutting than in root tip cutting in the concentration of 1.0, 1.5 & 2.0 mg/l IBA + 1.0 mg/l BAP combination. The highest callus weight was found in the cultured leaf cutting than root tips cutting at the concentration of 1.5mg/l IBA+1.0 mg/l BAP. Furthermore, the highest inverted sugar and glucose, chlorophyll and nutrient content (K+, NO3- & Ca++), total phenol, flavonoid and total antioxidant were found in the concentration of 1.5mg/l IBA+1.0 mg/l BAP combination in both broccoli leaf and root cutting. The results seemed that it was best to use the combination of the IBA and BAP in the concentration of 1.0-2.0 mg/l and 1mg/l to regenerate root, leaf and callus cell proliferation of broccoli from the root tip and leaf cutting.
The palatal root of the first permanent molar is the most commonly deflected root into the maxillary sinus during extraction. A rational approach to the surgical removal of a root from the antrum is important. Some surgeons prefer the alveolar approach while others prefer the Caldwell-Luc operation. A case is presented where the palatal root tip of the left upper first molar was removed from the maxillary sinus by the Caldwell-Luc approach with simultaneous closure of the oro-antral fistula resulting from dental extraction. A fibreoptic light probe was used. The advantages and disadvantages as well as how to avoid the common complications of this surgical technique are discussed. A good result was achieved with successful removal of the root and no loss of sensibility of the teeth and/or gum for this case.
Auxin and cytokinin regulate different critical processes involved in plant growth and environmental feedbacks. These plant hormones act either synergistically or antagonistically to control the organisation, formation and maintenance of meristem. Meristem cells can be divided to generate new tissues and organs at the locations of plant postembryonic development. The aboveground plant organs are created by the shoot apical meristem (SAM). It has been proposed that the phytohormone, cytokinin, plays a positive role in the shoot meristem function, promotes cell expansion and promotes an increasing size of the meristem in Arabidopsis, whereas it has the reverse effects in the root apical meristem (RAM). Over the last few decades, it has been believed that the apically derived auxin suppresses the shoot branching by inactivating the axillary buds. However, it has recently become clear that the mechanism of action of auxinis indirect and multifaceted. In higher plants, the regulatory mechanisms of the SAM formation and organ separation are mostly unknown. This study reviews the effects and functions of cytokinin and auxin at the shoot apical meristem. This study also highlights the merger of the transcription factor activity with the actions of cytokinin/auxin and their complex interactions with the shoot meristem in rice.
The potential genotoxic effects of methanolic extracts of Euphorbia hirta which is commonly used in traditional medicine to treat a variety of diseased conditions including asthma, coughs, diarrhea and dysentery was investigated using Allium cepa assay. The extracts of 125, 250, 500 and 1,000 µg/mL were tested on root meristems of A. cepa. Ethylmethanesulfonate was used as positive control and distilled water was used as negative control. The result showed that mitotic index decreased as the concentrations of E. hirta extract increased. A dose-dependent increase of chromosome aberrations was also observed. Abnormalities scored were stickiness, c-mitosis, bridges and vagrant chromosomes. Micronucleated cells were also observed at interphase. Result of this study confirmed that the methanol extracts of E. hirta exerted significant genotoxic and mitodepressive effects at 1,000 µg/mL.
The effect of preculture with different sugars and mannitol on cryopreservation of scalps of the banana (Musa) cvs. Pisang Mas, Pisang Nangka, Pisang Berangan and Pisang Awak was investigated. Scalps (0.3 square cm) were precultured on semi-solid MS-based medium, containing 0.4 or 0.5 M sucrose, glucose, fructose, trehalose or mannitol, for 14 days under a 16 h light and 8 h dark photoperiod prior to rapid cooling and storage in liquid nitrogen. Explants were rewarmed rapidly in a water bath at 40 degree C for 1 min, followed by recovery on two layers of sterile filter paper overlaying 25 ml aliquots of semi-solid MS-based medium with 5 mg per liter benzylaminopurine, 0.2 mg per liter indole acetic acid and 10 mg per liter ascorbic acid (PM8 medium) for 2 days in the dark. Subsequently, scalps were transferred onto 25 ml aliquots of semi-solid PM8 medium and incubated in the dark for 1 week prior to incubation in the light. Shoot regeneration from 5 - 48 percent of cryopreserved scalps of all the banana cvs., was observed only following preculture with 0.4 or 0.5 M glucose or fructose, and with 0.4 M trehalose for the cvs. Pisang Berangan and Pisang Awak. Preculture with 0.4 M glucose resulted in maximum shoot regeneration of cryopreserved scalps of 10 percent, 13 percent, 42 percent and 48 percent for the cvs. Pisang Mas, Pisang Nangka, Pisang Berangan and Pisang Awak, respectively. Concentrations of 0.5 M trehalose, or 0.4 and 0.5 M sucrose or mannitol were extremely toxic to scalps of all the cvs. investigated.
The effects of sucrose preculture duration and loading treatment on tolerance of Garcinia cowa shoot tips to cryopreservation using the PVS2 vitrification solution were investigated. Ultrastructural changes in meristematic cells at the end of the preculture and loading steps were followed in an attempt to understand the effects of these treatments on structural changes in cell membranes and organelles. Increasing preculture duration on 0.3 M sucrose medium from 0 to 3 days enhanced tolerance to PVS2 solution from 5.6 percent (no preculture) to 49.2 percent (3-day preculture). However, no survival was observed after cryopreservation. Examination of meristematic cells by transmission electron microscopy revealed the progressive accumulation of an electron-dense substance in line with increasing exposure durations to 0.3 M sucrose preculture. Treatment with a loading solution (2 M glycerol + 0.4 M sucrose) decreased tolerance of shoot tips to PVS2 vitrification solution and had a deleterious effect on the ultrastructure of G. cowa meristematic cells. This study suggests that G. cowa meristematic cells may lose their structural integrity due to exposure to glycerol present in the loading solution at a 2 M concentration, either due to its high osmotic potential, or due to its cytotoxicity.
The process of somatic embryogenesis and plant regeneration involve changes in gene expression and have been associated with changes in DNA methylation. Here, we report the expression and DNA methylation patterns of SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK), BABY BOOM (BBM), LEAFY COTYLEDON 2 (LEC2) and WUSCHEL (WUS) in meristematic block of newly emerged shoots from rhizome, embryogenic and non-embryogenic calli, prolonged cell suspension culture, ex vitro leaf, and in vitro leaf of regenerated plants of Boesenbergia rotunda. Among all seven samples, based on qRT-PCR, the highest level of expression of SERK, BBM and LEC2 was in embryogenic callus, while WUS was most highly expressed in meristematic block tissue followed by embryogenic callus. Relatively lower expression was observed in cell suspension culture and watery callus for SERK, LEC2 and WUS and in in vitro leaf for BBM. For gene specific methylation determined by bisulfite sequencing data, embryogenic callus samples had the lowest levels of DNA methylation at CG, CHG and CHH contexts of SERK, LEC2 and WUS. We observed negative correlation between DNA methylation at the CG and CHG contexts and the expression levels of SERK, BBM, LEC2 and WUS. Based on our results, we suggest that relatively higher expression and lower level of DNA methylation of SERK, BBM, LEC2 and WUS are associated with somatic embryogenesis and plant regeneration in B. rotunda.
Cone-beam-computed-tomography (CBCT) has been useful in providing insights of relevant anatomy prior to surgical
procedures, including the assessment of the proximity of impacted mandibular-third-molar to the inferior-alveolar-canal
(IAC). It is important to understand the reliability of conventional panoramic-radiograph in the assessment of this criterion
since it is more commonly used as first line radiographic approach due to its availability and lower radiation dose. This
study aimed to investigate the reliability of conventional panoramic-radiograph in the evaluation of the proximity of
impacted mandibular-third-molar root tip to the IAC by correlating the results with CBCT. A total of 65 root tips of impacted
mandibular-third-molars that had both panoramic radiographs and CBCT images were included in this retrospective study.
Two trained observers participated in all image evaluations. A prepared standard 1 cm ruler was used to measure the
proximity of the third-molar root apices to the IACs. Measurements recorded in this study were categorized into positive
(root apex above a roof of IAC), zero (root apex was superimposed on IAC) and negative (root apex below a roof of IAC).
Data analysis was carried out using student t-test. In this study, both observers recorded statistically significant differences
in the measurement between third-molars root apices and the IAC from panoramic radiographs and CBCT images. The low
reliability of panoramic radiograph to assess the vertical proximity between these two anatomical structures suggests
the importance of additional assessment with CBCT in cases where panoramic radiograph shows superimposition of the
third molar root on the roof of the canal and presence of root below the roof of the IAC.
Tissue culture studies of Celosia cristata were established from various explants and the effects of various hormones on morphogenesis of this species were examined. It was found that complete plant regeneration occurred at highest percentage on MS medium supplemented with 2.0 mg/L NAA and 1.5 mg/L BAP, with the best response showed by shoot explants. In vitro flowering was observed on MS basal medium after six weeks. The occurrence of somaclonal variation and changes in cellular behavior from in vivo and in vitro grown plants were investigated through cytological studies and image analysis. It was observed that Mitotic Index (MI), mean chromosome numbers, and mean nuclear to cell area ratio of in vitro root meristem cells were slightly higher compared to in vivo values. However, in vitro plants produced lower mean cell areas but higher nuclear areas when compared to in vivo plants. Thus, no occurrence of somaclonal variation was detected, and this was supported by morphological features of the in vitro plants.
Chitinase is an enzyme that catalyzes the degradation of chitin, commonly induced upon the attack of pathogens and other stresses. A cDNA (MsChi1) was isolated from Metroxylon sagu and expressed predominantly in the inflorescence tissue of M. sagu, suggesting its role in developmental processes. The chitinase cDNA was detected and isolated via differential display and rapid amplification of cDNA ends (RACE). Primers specific to M. saguchitinase were used as probes to amplify the 3'-end and 5'-end regions of chitinase cDNA. Transcript analysis showed that chitinase is expressed in inflorescence and meristem tissues but was not detected in the leaf tissue. Sequence analysis of amplified cDNA fragments of 3'-end and 5'-end regions indicated that the chitinase cDNA was successfully amplified. The M. saguchitinase cDNA isolated was approximately 1,143 bp long and corresponds to 312 predicted amino acids. Alignments of nucleotide and amino acid have grouped this chitinase to family 19 class I chitinase.
Limited information is available that seed biopriming with plant growth-promoting Enterobacter spp. play a prominent role to enhance vegetative growth of plants. Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure cultures were screened and three strains showed high P- and K-solubilizing capabilities. Light microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All Enterobacter spp. shared common plant growth-promoting traits, namely nitrogen (N2) fixation, indole-3-acetic acid production and siderophore production. The strains 38 and 40a were able to produce gibberellic acid, while only strain 38 was able to secrete exopolysaccharide on agar. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, Enterobacter spp. significantly improved overall germination parameters and vigor index (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot experiment of bioprimed seeds of okra seedling showed significant improvement of the plant growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of bioprimed plants were increased by up to 29% and 9% respectively. This report revealed that the under-explored species of P- and K-solubilizing Enterobacter hormaechei sp. with multiple plant beneficial traits presents a great potential sustainable approach for enhancement of soil fertility and P and K uptakes of plants.
Jatropha curcas L. or the physic nut is a monoecious shrub belonging to the Euphorbiaceae family. The plant is an ideal feedstock for biodiesel production; oil-rich seed (37-42%), has a broad range of growth habitat such as arid, semi-arid and tropical and a relatively feasible process for conversion of crude oil into biodiesel. The major constraint affecting the success of large-scale J. curcas plantation is seed yield inconsistency. Numerous research projects conducted on J. curcas with integrated genetic, genomic and transcriptomic approaches have been applied on the leaf, apical meristem, flower, root and fruit tissues. However, to date, no genomics data of J. curcas shoot system are publicly available, despite its importance in understanding flowering, fruiting and seed set qualities targeted for yield improvement. Here, we present eighteen sets of shoot and inflorescence transcriptomes generated from J. curcas plants with contrasting yields. Raw reads of the RNA-seq data are found in NCBI׳s Sequence Read Archive (SRA) database with the accession number SRP090662 (https://www.ncbi.nlm.nih.gov/sra/?term=SRP090662). This transcriptomic data could be integrated with the present genomic resources for in depth understanding of J. curcas reproductive system.
Sugarcane yellow leaf virus (SCYLV) was detected for the first time in 1996 in the Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD) sugarcane quarantine at Montpellier by reverse transcription-polymerase chain reaction (RT-PCR) in varieties from Brazil, Florida, Mauritius, and Réunion. Between 1997 and 2000, the virus was found by RT-PCR and/or tissue-blot immunoassay (TBIA) in additional varieties from Barbados, Cuba, Guadeloupe, Indonesia, Malaysia, Philippines, Puerto Rico, and Taiwan, suggesting a worldwide distribution of the pathogen. An excellent correlation was observed between results obtained for the two diagnostic techniques. However, even though only a few false negative results were obtained by either technique, both are now used to detect SCYLV in CIRAD's sugarcane quarantine in Montpellier. The pathogen was detected by TBIA or RT-PCR in all leaves of sugarcane foliage, but the highest percentage of infected vascular bundles was found in the top leaves. The long hot water treatment (soaking of cuttings in water at 25°C for 2 days and then at 50°C for 3 h) was ineffective in eliminating SCYLV from infected plants. Sugarcane varieties from various origins were grown in vitro by apical bud culture and apical meristem culture, and the latter proved to be the most effective method for producing SCYLV-free plants.