Postnatal development of rat retina:a continuous observation and comparison between the organotypic retinal explant model and in vivo development

The organotypic retinal explant culture has been established for more than a decade and offers a range of unique advantages compared with in vivo experiments and cell cultures.However,the lack of systematic and continuous comparison between in vivo retinal development and the organotypic retinal explant culture makes this model controversial in postnatal retinal development studies.Thus,we aimed to verify the feasibility of using this model for postnatal retinal development studies by comparing it with the in vivo retina.In this study,we showed that postnatal retinal explants undergo normal development,and exhibit a consistent structure and timeline with retinas in vivo.Initially,we used SOX2 and PAX6 immunostaining to identify retinal progenitor cells.We then examined cell proliferation and migration by immunostaining with Ki-67 and doublecortin,respectively.Ki-67-and doublecortin-positive cells decreased in both in vivo and explants during postnatal retinogenesis,and exhibited a high degree of similarity in abundance and distribution between groups.Additionally,we used Ceh-10 homeodomain-containing homolog,glutamate-ammonia ligase(glutamine synthetase),neuronal nuclei,and ionized calcium-binding adapter molecule 1 immunostaining to examine the emergence of bipolar cells,Müller glia,mature neurons,and microglia,respectively.The timing and spatial patterns of the emergence of these cell types were remarkably consistent between in vivo and explant retinas.Our study showed that the organotypic retinal explant culture model had a high degree of consistency with the progression of in vivo early postnatal retina development.The findings confirm the accuracy and credibility of this model and support its use for long-term,systematic,and continuous observation.

Punch‑excised explants of bovine mammary gland to model early immune response to infection

Background Mammary gland(MG)infections(mastitis)are frequent diseases of dairy cows that affect milk quality,animal welfare and farming profitability.These infections are commonly associated with the bacteria Escherichia coli and Staphylococcus aureus.Different in vitro models have been used to investigate the early response of the MG to bacteria,but the role of the teat in mastitis pathogenesis has received less attention.In this study,we used punch-excised teat tissue as an ex vivo model to study the immune mechanisms that arise early during infection when bacteria have entered the MG.Results Cytotoxicity and microscopic analyses showed that bovine teat sinus explants have their morphology and viability preserved after 24 h of culture and respond to ex vivo stimulation with TLR-agonists and bacteria.LPS and E.coli trigger stronger inflammatory response in teat when compared to LTA and S.aureus,leading to a higher produc-tion of IL-6 and IL-8,as well as to an up-regulation of proinflammatory genes.We also demonstrated that our ex vivo model can be applied to frozen-stored explants.Conclusions In compliance with the 3Rs principle(replacement,reduction and refinement)in animal experimenta-tion,ex vivo explant analyses proved to be a simple and affordable approach to study MG immune response to infec-tion.This model,which better reproduces organ complexity than epithelial cell cultures or tissue slices,lends itself particularly well to studying the early phases of the MG immune response to infection.

Different Explants of Lilium lancifolium Have Different Potential to Differentiate and Regenerate in Tissue Culture

[Objective] The aim was to investigate differences in differentiation and regeneration of the explants from different parts of Lilium lancifolium（Yixing Lily） in tissue culture.[Method] The different parts of scale,leaf and root of Yixing Lily were cultured as explants on MS basic medium supplemented with different concentrations of plant growth regulators,so as to compare their capacity to differentiate and regenerate.[Result] The explants had different potential to differentiate（scale root leaf）.The capacity of different scale parts to differentiate was the lower part middle partupper part;the capacity of different leaf parts to differentiate was the leaf base middle part leaf tip;the capacity of different root parts to differentiate was the root base root tip middle part.[Conclusion] Tissue culture could be well applied in propagation of Yixing Lily.

Study on Explants Sterilization and Callus Induction of Aquilegia oxysepala

[Objective] The aim was to study the explants sterilization and callus induction of Aquilegia oxysepala.[Method] the seeds of Aquilegia oxysepala were sterilized by different kinds and concentrations of disinfectants,and the pollution rate and pollution speed were investigated so as to find the best way to build sterile seedling setup.Taking the roots,stem segments and leaves of the sterile seedlings from Aquilegia oxysepala seeds as explants,the optimum explants and medium were screened by adding MS basic medium with different hormone proportions.[Result] The best germicidal treatment was as follows：explants were soaked in 75% alcohol for 30 s firstly,washed by sterile water for 5 times,then soaked in 0.2% mercuric chloride liquid for 2 min,finally washed by sterile water for 5 times again.The sterilization treatment could get the lowest pollution rate,the highest germinating capacity and the best sterile seedling.Roots were the optimum explants for the callus induction of Aquilegia oxysepala,meanwhile the optimal medium was MS＋0.6 mg/L 2,4-D＋0.5 mg/L 6-BA.[Conclusion] The research provides technical support for the large scale production of Aquilegia oxysepala and also makes a contribution to the medicinal and ornamental value of Aquilegia oxysepala.

Investigation on the Morphological Characteristics of Dendrobium officinale Plantlets Propagated from Different Explants

[ Objective] This study aimed to investigate the differences in morphological characteristics of Dendrobium officinale plantlets propagated from different explants. [ Method] Randomly 1 000 D. offtcinale plantlets propagated via different regeneration pathways were selected for morphological investigation and classification. [ Result] D. officinale plantlets propagated from stem segment explants exhibited highly consistent morphological characteristics, while those propagated from seed explants exhibited a variety of morphological characteristics. [ Conclusion] Therefore, using seed explants for regeneration can effectively broaden the germplasms resources of D. officinale.

Study on the Explant Disinfection of Root Culture of Hevea brasiliensis

[Objective] The aim was to look for an effective way of decreasing explants contamination in the root tissue culture of Hevea brasiliensis.[Method] In order to study root tissue culture of H.brasiliensis,new roots from forest section after treatment for one month were as explants,and 1 g/L carbendazim,75% ethanol,0.1% mercuric chloride and Yipeilong with different concentrations were used as disinfectants for roots disinfection.[Result] Before conventional disinfection,root explants were treated by 1 g/L carbendazim for 2.5 h,and disinfected by 75% ethanol for 30 s and 0.1% HgCl2 for 6 min,then cultured on the callus induction medium supplemented with 0.1% Yipeilong.The results showed that the contamination rate of explants decreased to 44.59%,and 25.60% explants survived after cultured for 30 d.[Conclusion] The study could provide theoretical foundation for the decrease of explant contamination in the root tissue culture of H.brasiliensis.

Establishment of high frequency shoot regeneration system in Himalayan poplar(Populus ciliata Wall. ex Royle) from petiole explants using Thidiazuron cytokinin as plant growth regulator

Populus species are important resources for industry and in scientific study on biological and agricul- tural systems. Our objective was to enhance the frequency of plant regeneration in Himalayan poplar （Populus ciliata wall. ex Royle）. The effect of TDZ alone and in combi- nation with adenine and NAA was studied on the regen- eration potential of petiole explants. The explants were excised from Himalayan poplar plants grown in glass- houses. After surface sterilization the explants were cul- tured on shoot induction medium. High percentage shoot regeneration （86 %） was recorded on MS medium sup- plemented with 0.004 mg L-1 TDZ and 79.7 mg L-1 adenine. The regenerated shoots for elongation and multi- plication were transferred to MS ＋ 0.5 mg L-1 BAP ＋ 0.2 mg L-1 IAA ＋ 0.3 mg L-1 GA3. Root re- generation from shoots developed in vitro was observed on MS medium supplemented with 0.10 mg L-1 IBA. Hi- malayan poplar plantlets could be produced within 2 months after acclimatization in a sterile mixture of sand and soil. We developed a high efficiency plant regeneration protocol from petiole explants of P. ciliata.

Differentiation potential of human adipose tissue derived stem cells into photoreceptors through explants culture and enzyme methods

AIM： To investigate the retinal photoreceptor differentiation potential of human orbital adipose tissue-derived stem cells （ADSCs） generated by enzyme （EN） and explant （EX） culture methods.METHODS： We investigated potentials of human orbital ADSCs to differentiate into photoreceptors through EN and EX culture methods. EN and EX orbital ADSCs were obtained from the same donor during rehabilitative orbital decompression, and then were subject to a 3-step induction using Noggin, DKK-1, IGF-1 and b-FGF at different time points for 38d. Stem cell, eye-field and photoreceptor-related gene and protein markers were measured by reverse transcription-polymerase chain reaction （RT-PCR） and immunofluorescent （IMF） staining.RESULTS： Both EX and EN orbital ADSCs expressed CD133, a marker of cell differentiation. Moreover, PAX6 and rhodopsin, markers of the retinal progenitor cells, were detected from EX and EN orbital ADSCs. In EX orbital ADSCs, PAX6 mRNA was detected on the 17th day and then the rhodopsin mRNA was detected on the 24th day. In contrast, the EN orbital ADSCs expressed PAX6 and rhodopsin mRNA on the 31st day. EX orbital ADSCs expressed rhodopsin protein on the 24th day, while EN orbital ADSCs expressed rhodopsin protein on the 31st day. CONCLUSION： Orbital ADSCs isolated by direct explants culture show earlier and stronger expressions of markers towards eye field and retinal photoreceptor differentiation than those generated by conventional EN method.

An Improved System for Shoot Regeneration from Stem Explants of Lombardy Poplar (Populus nigra L. var. italica Koehne)

We developed a system for the regeneration of Lombardy poplar (Populus nigra L. var. italica) shoots from internodal stem explants. Using this system, shoots regenerated from 87% of the stem explants placed on Murashige and Skoog (MS) medium supplemented with 0.1 mg/L indole-3-acetic acid and 0.5 mg/L benzylaminopurine without undergoing callus formation. About 80% of the in vitro regenerated shoots developed roots on MS medium supplemented with 0.5 mg/L indole-3-butyric acid and 0.02 mg/L 1-naphthylacetic acid. Well-rooted seven-to eight-week-old regenerated plants could be transferred to soil for further growth and the survival rate of such plants after three weeks was 88%. The protocol presented here is simple and economical because it does not rely on pre-incubation in callus induction medium or repeated subculture in shoot induction medium containing trans-zeatin, an expensive substance. The in vitro regeneration system presented here could be used for evaluation of radiation sensitivity for Lombardy poplar tissues.

The Influence of Endogenous Hormones on Culture Capability of Different Explants in Rice

The endogenous hormones (EHs) content of different explants (anther, young panicle, young embryo and mature embryo) and calli with different culture capability were analyzed by means of high performance liquid chromatography (HPLC). The results showed that the contents and ratio of endogenous hormones were one of the key factors affecting callus induction frequencies (CIF) and green plantlet differentiation frequencies (GPDF). The influence of endogenous hormones of different explants on CIF represented as: Zoatin ribosile (ZR) showed negative effect, indole-3-acetic acid (IAA) did positive effect, and gibberellic acid (GA) did negative effect except for mature embryos. The influence of endogenous hormones on green plantlet differentiation frequency (GPDF) showed: IAA and GA were negative effect; abscisic acid (ABA) and zeatin+ zeatin riboside (Z+ZR) were positive effect. The mixture ratio of endogenous hormones played a role on CIF and GPDF. IAA/Z+ZR had a positive effect on CIF, and there was a notable positive correlation between Z+ZR/ IAA and GPDF, so was between ABA/IAA and GPDF.

In vitro clonal propagation of Achyranthes aspera L. and Achyranthes bidentata Blume using nodal explants

Objective:To develop the reproducible in vitro propagation protocols for the medicinally important plants viz.,Achyranthes aspera(A.aspera)L.and Achyranthes bidentata(A.bidentata)Blume using nodal segments as explants.Methods:Young shoots of A.aspera and A.bidentata were harvested and washed with running tap water and treated with 0.1%bavistin and rinsed twice with distilled water.Then the explants were surface sterilized with 0.1%(w/v)HgCl_2 solutions for I min.After rinsing with sterile distilled water for 3-4 times,nodal segments were cut into smaller segments(1 cm)and used as the explants.The explants were placed horizontally as well as vertically on solid basal Murashige and Skoog(MS)medium supplemented with 3%sucrose,0.6%(w/v)agar(HiMedia,Mumbai)and different concentration and combination of 6-benzyl amino purine(BAP),kinetin(Kin),naphthalene acetic acid(NAA)and indole acetic acid(IAA)for direct regeneration.Results:Adventitious proliferation was obtained from A.aspera and A.bidentata nodal segments inoculated on MS basal medium with 3%sucrose and augmented with BAP and Kin with varied frequency.MS medium augmented with 3.0 mg/L of BAP showed the highest percentage(93.60±0.71)of shootlets formation for A.aspera and(94.70±0.53)percentages for A.bidentata.Maximum number of shoots/explants(10.60±0.36)for A.aspera and(9.50±0.56)for A.bidentata was observed in MS medium fortified with 5.0 mg/L of BAP.For A.aspera,maximum mean length(5.50±0.34)of shootlets was obtained in MS medium augmented with 3.0 mg/L of Kin and for A.bidentata(5.40±0.61)was observed in the very same concentration.The highest percentage,maximum number of rootlets/shootlet and mean length of rootlets were observed in 1/2 MS medium supplemented with 1.0 mg/L of 1BA.Seventy percentages of plants were successfully established in polycups.Sixty eight percentages of plants were well established in the green house condition.Sixty five percentages of plants were established in the field.Conclusions:The results have shown that use of nodal buds is an alternative reproducible and dependable method for clonal propagation of A.aspera and A.bidentata.The high rate of direct shoot-root multiplication and their high rate of post-hardening survival indicate that this protocol can he easily adopted for commercial large scale cultivation.

Tissue Culture Responses from Different Explants of Rice

Different culture explants, including anther, young panicle, young embryo, and mature embryo, from 19 rice varieties were used for callus induction and green plantlet differentiation. The culture efficiency differed significantly among the four types of explants, and varied from genotype to genotype. Callus induction frequency presented significantly positive correlation each between anther and young panicle, anther and mature embryo, and young panicle and young embryo. Green plantlet differentiation showed no relationship between different types of explants. In addition, no relationship was found between callus induction frequency and green plantlet differentiation frequency.

Plant Regeneration from In Vitro Cultured Hypocotyl Explants of Euonymus japonicus Cu zhi

Adventitious shoots were successfully regenerated from hypocotyl explants of in vitro cultures of Euonymus japonicus Cu zhi. Hypocotyl slices were cultured on Murashige and Skoog （MS） and B5 basal medium supplemented with varied concentration of different plant growth-regulators, e.g., α-naphthaleneacetic acid （NAA） and indole-3-butyric acid （IBA） in combination with 6-benzylaminopurine （6-BA） and kinetin. The study showed that shoots could be directly regenerated from hypocotyl explants without the intervening callus phase; MS medium was more suitable for adventitious shoots regeneration. The ability of hypocotyls segments to produce shoots varied depending upon their position on the seedlings. The highest regeneration rate was obtained with hypocotyl segments near to the cotyledon cultured on MS basal medium supplemented with 1.5 mg L^-1 6-BA and 0.05 mg L^-1 NAA （63.64%）. The regenerated shoots were readily elongated on the same medium as used for multiplication and rooted on half-strength MS basal medium supplemented with 1.0 mg L^-1 IBA and 100 mg L^-1 activated carbon. After being transferred to greenhouse conditions, 96% of the plantlets were successfully acclimatized. This regeneration system is applied for genetic transformation now.

A pilot study of intraocular lens explantation in 69 eyes in Chinese patients

AIM：To study the effects of intraocular lens（IOL） explantation and demographic characteristics.METHODS：Retrospective non-comparative case series.Clinical data recorded from patient charts included the following：demographic,preoperative and postoperative characteristics;complications;surgical methods,and changes in visual acuity.RESULTS：A total of 69 eyes in 67 Chinese patients who received IOL explants were studied.The patients＇ mean age at the time of explantation was 46.1 years old [SD 22.5（6-85）],and 37 patients were female（55.2%）.Regarding employment,47.8% were farmers,23.9% were retired,16.4% were students,4.5% were unemployed,3% were workers,and 4.5% were other（including staff members,teachers and officers）.The main reasons for explantation were dislocation/decentration in 41 cases（59.4%） and retinal detachment in 10 cases（14.5%）.The third most prevalent cause was incorrect lens power in 7 eyes（10.1%）.The remaining reasons were endophthalmitis in 6 cases（8.7%）,posterior capsular opacity in 3 eyes（4.3%）,and impacting retinal surgery operation in 2 cases（2.9%）.The main comorbidities were high myopia in 18 eyes（26.1%）,trauma in 8 eyes（11.6%）,retinal detachment in 6 eyes（8.7%）,congenital cataracts in 8 eyes（11.6%）,and Marfan＇s syndrome in 2 eyes（2.9%）.The mean time from implantation to explantation was 4.0y [SD 4.2（0.005-15）].Treatment after explantation included posterior chamber IOL implantation in 44 eyes（63.8%） and aphakia in 25 eyes（36.2%）.After surgery,the best corrected visual ability（BCVA） was improved in 50 cases（72.5%）,including 28 patients（40.6%） in whom visual ability was improved by more than two lines.CONCLUSION：Dislocation/decentration is the main cause for explantation,and high myopia is a main risk factor.Posterior chamber IOL implantation remains the most elected treatment after explantation.

Effect of peripheral nerve on the neurite growth from retinal explants in culture

The effect of peripheral nerve (PN) on neurite outgrowth from retinal explants of adult hamsters was examined. Cultures of retinal explants, and co-cultures of retinal explants and PN were performed using chick retinal basement membrane (BM) as substrate. The presence of PN increases the number and length of neurite outgrowth. In addition, a high proportion of neurites situated close to PN tend to grow towards it. Since there was no contact between retinal ex-plants and PN, we suggest that PN might secrete diffusible substances to attract the neurites to grow towards it.

Indications for exchange or explantation of phakic implantable collamer lens with central port in patients with and without keratoconus

AIM:To evaluate the causes of phakic implantable collamer lens(ICL)exchange/explantation in patients with and without keratoconus(KC)at two tertiary hospitals in Riyadh,Saudi Arabia.METHODS:A retrospective chart review of all patients who underwent ICL(model V4 c with central port)exchange/explantation was performed using the electronic medical record systems.All available preoperative and postoperative data were documented for each patient.RESULTS:Over 7 y,2283 ICL implantation procedures were performed;46 implants(2%)required exchange(21 implants)/explantation(25 implants),of which 14 cases(30.4%)were patients with KC.Indications for ICL exchange/explantation in non-KC group were vault measurement,cataract formation,increased intraocular pressure,inaccurate refraction,and patient dissatisfaction in 22(68.75%),4(12.5%),3(9.37%),2(6.25%),and 1(3.12%)case,respectively.The most common indication for ICL exchange/explantation in the KC group was inaccurate vault sizing in 11 patients(78.57%),inaccurate refraction in 2 patients(14.28%),and patient dissatisfaction postoperatively in 1(7.14%)case.CONCLUSION:ICL implantation results in predictable refractive outcomes over the long term with exchange/explantation rates comparable to previous literature.Improper vault size is the most common cause of ICL exchange/explantation among patients with or without KC.

Enzymatic Cell Isolation and Explant Cultures of Rat Calvarial Osteoblast Cells

Osteoblast cells were isolated from the calvarial bones of newborn Wistar rats and cultured in vitro via both collagenase digestion method and explant technique, and a comparative study was carried out on the two culture methods. The biologic charwteristics of the osteoblast cells were studied via cell number counting, morphology observation, alkaline phosphatase staining of the cells and alizarine- red staining of the calcified nodules. The results show that osteoblast cells can be cultured in vitro via collagenase digestion method and explant technique, and the obtained cells ure of good biologic characteristics. In comparison with the explant technique, the operative procedure of the enzymatic digestion method is more complicated. The digestion time must be carefully controlled. However, with this method, one can obtain a lager number of cells in a short time. The operative procedure of the explant technique is simpler, but it usually takes longer time to obtain cells of desirable number.

Different culture conditions applied to in vitro shoot multiplication of two Eucalyptus benthamii explant sources

Eucalyptus adult material requires more successive subcultures in the in vitro multiplication phase for increased vigor and cellular activity. This study evaluated the endophytic manifestation and shoot multiplication of one 13-year-old Eucalyptus benthamii clone under different culture conditions and used canopy branches(CB) and trunk base material as explant sources. The culture media were wood plant medium(WPM), Murashige and Skoog medium(MS) and JADS(Correia and co-authors medium).Based on the results of the initial multiplication experiment, further tests examined sucrose concentrations and p H. Morphophysiology, dry mass production, endophyticmanifestation and histochemical were determined. Explant sources responded differently to MS and JADS media, but the WPM medium promoted homogeneous development.The responses were similar for both explant sources when sucrose concentrations varied. Shoots died in the absence of sucrose, showed high oxidation at 60 g L-1 and optimal development at 30 g L-1. Endophytes were more evident for shoots from the CB origin. Explant sources responded distinctively to treatment due to physiological and intrinsic genetic factors. Therefore, explant sources, different culture media, sucrose concentration and p H may determine micropropagation success and influence the presence and/or intensity of endophytic manifestation.

Study on Initial Explants Induction of Litsea cubeba

[ Objectlve] The aim of this study was to explore an explants induction method for L. cubeba. [ Method ] Different types of L. cubeba stem segments were collected at different time as explants materials for induction and culture. [ Result ] The results showed that sterilization with 0. 1% HgC12 for 10 min achieved better effects, with an explants contamination rate of dO. 0% and a mortality rate of 15.0% ; stem segments of the 2na -5th buds below the terminal bud were better explants materials for initial induction; the best sampling time was January, with an induction rate as high as 81.1%, while the contamination rate was only 11.7% ; modified MS ＋ 1.0 mg/L of 6-BA ＋ 0.2 mg/L of NAA was the optimal medium for explants induction of L. cubeba. [ Conclusion] Semi-lignified stem segments of L cubeba collected in January, sterilized with 0.1% HgCI2 for 10 min and cultured in modified MS ＋ 1.0 mg/L of 6-BA ＋ 0.2 mg/L of NAA a- chieved better induction effects on L. cubeba seedlings.

Plantlet regeneration from mature zygotic embryos andembryonic explants of masson pine (Pinus massoniana Lamb.)

Excised zygotic embryos, cotyledons and hypocotyls of juvenile seedlings of masson pine were grown on DCR medium supplemented with several concentrations of various plant phytohormones. BA (1.0 mg/ L) in combination with NAA (0.05 mg/L)in DCR medium was found to increase the formation of adventitious buds from mature zygotic embryos, but most of them were formed at the tips of embryonic cotyledons. Adventitious buds were obtained from cotyledons and hypocotyls from juvenile seedlings when they were cultured on DCR medium containing BA 3-5 mg/L and NAA 0.1-0.2 mg/L. Elongation of buds were observed on hormone-free DCR medium with or without activated charcoal (0.5%). Root initiation was achieved with full or half strength DCR inedium supplemented with IBA 1.0 mg/L and NAA 0.25-0.5 mg/L. Approximately 11-20 axillary buds formed on each explant when juvenile seedling explants were treated (3-20h) with BA 50-100 mg/L, followed by transfer to hormone-free DCR medium. The maximum number of shoots obtained per explant within six months was 33.