Cultivating <Emphasis Type="Italic">in vitro</Emphasis> coconut palms (<Emphasis Type="Italic">Cocos nucifera</Emphasis>) under glasshouse conditions with natural light,improves <Emphasis Type="Italic">in vitro</Emphasis> photosynthesis nursery survival and growth

Plantlets of coconut were cultured in vitro under three different ambient conditions including a standard culture room, a culture room inside a glasshouse with natural light but controlled temperature, and a standard glasshouse with natural light and natural fluctuations of temperature. Plantlets from the 3 treatments were compared in terms of growth, plant survival as well as net photosynthesis and efficiency of PSII (Fv/Fm ratio) both at the end of the in vitro stage and at 3 stages of ex vitro acclimatization. At the end of the in vitro stage, plantlets cultured in vitro under glasshouse conditions showed the best performance showing the highest photosynthesis rate, dry weight and number of leaves. Plantlets from the standard culture room showed the lowest photosynthesis and growth rate. After 6 months of ex vitro acclimatization, plantlets originally grown in vitro under glasshouse conditions maintained better field survival and growth rates in terms of fresh weight, dry weight and leaf number than plantlets originally grown in vitro in the standard culture room. Although more studies are required to define the reason for this effect, it is clear that the conditions of standard culture rooms are not the best for in vitro cultivation of coconut and perhaps other tropical species.     

大葱组织培养中玻璃苗特性研究

以章丘大葱为试验材料,从形态组织学及生理生化等方面探讨了大葱试管苗玻璃化发生的可能机理。结果表明,玻璃苗形态组织结构与正常苗有很大差异,玻璃苗组织含水量增加,过氧化物酶(POD)活性增强,叶绿素总量、叶绿素a、叶绿素b、过氧化氢酶(CAT)的活性、可溶性蛋白含量均降低。玻璃苗酯酶同工酶谱带与正常苗相比,增加了一条带,同时缺少了两条带;可溶性蛋白电泳分析表明,玻璃苗与正常苗间也存在明显差异。可见,当外界环境条件不适宜植物生长需要时,植物体在基因表达水平上将会受到影响,表达产物的差异可引起生理代谢功能上的紊乱,从而导致形态结构的畸型,进而产生玻璃化苗。     

High frequency of plant regeneration from hypocotyl explants of Brassica carinata A. Br.

An efficient tissue culture system for high frequency of plant regeneration from hypocotyl explants of Brassica carinata was developed via manipulation of culture medium and selection of explants. Explants grown on medium containing combinations of 2 mg l^-1 BA and 0.01 mg l^-1 NAA or 4 mg l^-1 kinetin and 0.01 mg l^-1 2,4-D regenerated shoots at 100% frequency. High frequency shoot regeneration occurred only from explants originating from 6 to 7-day-old but not younger or older seedlings. Explants showed higher regeneration capacity at the distal end than the proximal end, and the upper segment was more regenerative than the lower segment of hypocotyl. Regenerants were rooted on half-strength growth regulator-free medium, acclimatized and developed into normal, fertile plants.Abbreviations BA benzyladenine - 2-4-D 2,4-dichlorophenoxyacetic acid - NAA naphthaleneacetic acid - MS Murashige & Skoog     

Matrix Metalloproteinases of Normal Human Tissues

This review considers biochemical properties of the family of matrix metalloproteinases (MMPs) of normal human tissues and the involvement of these enzymes in morphogenesis. Four main MMP subfamilies are characterized, and a group of other MMPs is described. Data on mechanisms of activation and inhibition of MMPs in certain tissues during various physiological processes (embryogenesis, angiogenesis, tissue growth and involution) are considered. Information about tissue inhibitors of MMP is presented, and the ability of these inhibitors to regulate the activity of MMPs is analyzed.     

Detection and Quantification of Fusarium oxysporum f. sp. niveum Race 1 in Plants and Soil by Real-time PCR

Fusarium wilt caused by Fusarium oxysporum f. sp. niveum (Fon) is the most serious soil-borne disease in the world and has become the main limiting factor of watermelon production. Reliable and quick detection and quantification of Fon are essential in the early stages of infection for control of watermelon Fusarium wilt. Traditional detection and identification tests are laborious and cannot efficiently quantify Fon isolates. In this work, a real-time polymerase chain reaction (PCR) assay has been described to accurately identify and quantify Fon in watermelon plants and soil. The FONRT-18 specific primer set which was designed based on identified specific sequence amplified a specific 172 bp band from Fon and no amplification from the other formae speciales of Fusarium oxysporum tested. The detection limits with primers were 1.26 pg/μl genomic DNA of Fon, 0.2 pg/ng total plant DNA in inoculated plant, and 50 conidia/g soil. The PCR assay could also evaluate the relationships between the disease index and Fon DNA quantity in watermelon plants and soil. The assay was further used to estimate the Fon content in soil after disinfection with CaCN₂. The real-time PCR method is rapid, accurate and reliable for monitoring and quantification analysis of Fon in watermelon plants and soil. It can be applied to the study of disease diagnosis, plant-pathogen interactions, and effective management.     

甘蔗抗逆细胞系选择及其生化特性的研究

利用脯氨酸类似物羟脯氨酸(Hyp)的生长抑制作用,筛选出抗Hyp的甘蔗(Saccha-rum sinensis Roxb)细胞变异系R932。抗性系体内游离脯氨酸含量超常积累(×3．2)。而且其体内脯氨酸合成途径中的关键酶γ－谷氨酸激酶对脯氨酸的反馈抑制较不敏感。R932抗PEG和低温能力较供体加强。实验结果表明γ－谷氨酸激酶特性的变化可能导致细胞内脯氨酸的过量积累,脯氨酸的过量积累有利于植物细胞对抗恶劣环境。     

The role of monocyte/macrophages as vehicles of dissemination of Simkania negevensis: an in vitro simulation model

Exposure to Simkania negevensis (Sn), an intracellular microorganism that has been associated with respiratory tract infections in infants and adults, is prevalent. Sn can multiply within free-living amoebae and has been detected in domestic water supplies, which may constitute a source of infection with the organism. Its path of transport from its portal of entry to the body to its target organs is unknown. In this study, the possibility that monocytes/macrophages may serve as vehicles of transmission was examined. In vitro cocultivation of Sn-infected Acanthamoeba polyphaga with the monocyte/macrophage cell line U937 resulted in the death of the amoebae and infection of the U937 cells. Sn entered and multiplied in U937 cells within short periods of time, and the microorganism could be transferred from U937 cells to cell cultures of various origins. Uninfected monocyte/macrophages could become infected when in contact with either actively or persistently Sn-infected cell cultures. Persistently infected cultures in contact with uninfected U937 cells became actively infected. The results of this study provide a basis for determination of the molecular mechanisms of monocyte/macrophage-cell interactions in transfer of infection and may contribute to a better understanding of the pathogenesis of Sn infections in vivo.     

Myometrial‐derived CXCL12 promotes lipopolysaccharide induced preterm labour by regulating macrophage migration,polarization and function in mice

Preterm birth is a major contributor to neonatal mortality and morbidity. Infection results in elevation of inflammation‐related cytokines followed by infiltration of immune cells into gestational tissue. CXCL12 levels are elevated in preterm birth indicating it may have a role in preterm labour (PTL); however, the pathophysiological correlations between CXCL12/CXCR4 signalling and premature labour are poorly understood. In this study, PTL was induced using lipopolysaccharide (LPS) in a murine model. LPS induced CXCL12 RNA and protein levels significantly and specifically in myometrium compared with controls (3‐fold and 3.5‐fold respectively). Highest levels were found just before the start of labour. LPS also enhanced the infiltration of neutrophils, macrophages and T cells, and induced macrophage M1 polarization. In vitro studies showed that condition medium from LPS‐treated primary smooth muscle cells (SMC) induced macrophage migration, M1 polarization and upregulated inflammation‐related cytokines such as interleukin (IL)‐1, IL‐6 and tumor necrosis factor alpha (TNF‐α). AMD3100 treatment in pregnant mice led to a significant decrease in the rate of PTL (70%), prolonged pregnancy duration and suppressed macrophage infiltration into gestation tissue by 2.5‐fold. Further, in‐vitro treatment of SMC by AMD3100 suppressed the macrophage migration, decreased polarization and downregulated IL‐1, IL‐6 and TNF‐α expression. LPS treatment in pregnant mice induced PTL by increasing myometrial CXCL12, which recruits immune cells that in turn produce inflammation‐related cytokines. These effects stimulated by LPS were completely reversed by AMD3100 through blocking of CXCL12/CXCR4 signalling. Thus, the CXCL12/CXCR4 axis presents an excellent target for preventing infection and inflammation‐related PTL.     

Regeneration of plantlets from embryogenic suspension cultures of pickling cucumber (Cucumis Sativus L. CV. Endeavor)

Summary Procedures have been developed for the initiation and long-term maintenance of embryogenic suspension cultures of pickling cucumber (Cucumis sativus) cultivar Endeavor and for the regeneration of normal plantlets. Embryogenic calluses from petiole explants plated on Murashige and Skoog (MS) medium with 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BA), both at 5μM, were used to initiate the embryogenic suspension cultures. Among various growth regulator combinations evaluated for initiation and maintenance of these suspension cultures, only MS medium with 2,4-D and BA, both at 1μM, produced cultures that were yellow, friable, and still regenerable after repeated subculture (every two wk) over a 3- to 15-mo. period. The effects of various concentrations of auxin and cytokinin in the plating medium, the addition of AgNO₃, and various plating procedures were also evaluated. The highest frequency of regeneration of shoots and plantlets was achieved by plating aggregates onto filter paper overlaid on MS medium with naphthalene acetic acid (NAA)/BA at a concentration of 2:1 or 1:1μM. The addition of activated charcoal (0.5%) or AgNO₃ (30μM) in the plating medium did not enhance the frequency of plantlet regeneration. The highest frequency of normal-appearing plantlets recovered was 42 to 46% per petri dish. The procedures described in this study can be used to increase plantlet recovery from individual embryogenic calluses of pickling cucumber.