鹅黑素皮质素受体-4基因的克隆与序列分析

黑素皮质素受体-4（Melanocortin receptor-4,MC4R）是其黑素皮质素受体MCR（MC1-5R）家族成员之一,属G蛋白偶联受体。它可与瘦蛋白、神经肽、α-黑素细胞刺激素等一起调节动物体重和采食量。参考鸡MC4R基因序列设计引物,克隆并测序了鹅MC4R基因。结果表明,鹅MC4R基因编码区全长996 bp,其核苷酸序列与鸡的同源性为95.3%,与人、牛、猪等哺乳动物同源性在75%-79%;其氨基酸序列与鸡的同源性达到98.5%。构建哺乳类、鸟类和鱼类MC4R基因核苷酸进化树显示,鹅较早地与哺乳类动物分化开来。分析MC4R蛋白的氨基酸残基特性参数表明,MC4R的7次跨膜结构与MC4R的亲水性区域、电荷密度以及氨基酸残基位于表面概率的变化规律相一致。     

High frequency plantlet regeneration from callus and artificial seed production of rock plant Pogonatherum paniceum (Lam.) Hack. (Poaceae)

Pogonatherum paniceum (Lam.) Hack. is a rock plant with good potential for vegetative recovery on naked lands. A high frequency in vitro regeneration system was developed for P. paniceum. Calli were induced from explants of mature seeds, seedlings, young leaves, and stem segments on Murashige and Skoog (MS) medium supplemented with 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D), 2.0 mg L⁻¹ α-naphthalene acetic acid (NAA) and 0.2 mg L⁻¹ 6-benzylaminopurine (BAP). High induction rates (59.57%) and regeneration rates (100%) were obtained from mature seed explants; calli were sub-cultured for over 2 years and still retained a high regenerative capacity. One seed explant resulted in 69,997 plants in 1 year. Shoot buds derived from calli were used for encapsulation in liquid MS medium containing 3% sucrose and two different alginate matrices (3% sodium alginate (w/v) + MS medium containing 3% sucrose and 3% sodium alginate + 1% activated carbon (w/v) + MS medium containing 3% sucrose) with a 20-min exposure to 2% CaCl₂ and 0.3% bavistin (w/v). The capsule with 3.0% sodium alginate (w/v) and 1% activated carbon (w/v) showed a higher conversion rate (61.58%) and stronger plantlets under non-aseptic conditions. These systems are useful for the rapid clonal propagation and dissemination of artificial seed material of P. paniceum for eco-recovery.     

Cryopreservation of carnation (Dianthus caryophyllus L.) shoot tips by encapsulation-vitrification

Shoot tips excised from in vitro cultured plants of Dianthus caryophyllus L. (cv. Pallas, cv. Pink Candy and cv. Wanessa) were successfully cryopreserved using an encapsulation-vitrification method. Shoot tips (2–3 mm in length) were encapsulated in sodium alginate, precultured on liquid Murashige and Skoog (1962) medium supplemented with various sucrose concentrations (0.25, 0.5, 0.75, 1.0 M) for 24 h or 48 h and dehydrated with the vitrification solution PVS2 (up to 4 h) at 24 °C or 0 °C prior to direct immersion in liquid nitrogen (−196 °C). A maximum of shoot regeneration from cryopreserved shoot tips was obtained with the following combinations: preculture in 0.5 M sucrose and 180 min dehydration treatment at 0 °C for cv. Pallas (60% shoot formation), or preculture in 0.75 M and 200 min dehydration at the same temperature for cv. Pink Candy (66.6% shoot formation) and cv. Wanessa (73% shoot formation).     

Rooting response of shoot cuttings from three peach growth habits

Current year shoot cuttings were collected in October and August from three growth habits of peach (Compact, Pillar, and Standard) and treated with one of four concentrations of indole butyric acid (0, 250, 1250, and 2500 mg L⁻¹ IBA). Rooting response was measured after 5 weeks in the greenhouse. Little or no rooting occurred with cuttings from any growth habit that was collected in October or in August when treated with 0 and 2500 mg L⁻¹ IBA. In August, the number of shoots that rooted was greater in cuttings from Pillar (79 and 45%) than Compact (13 and 3%) treated with 250 and 1250 mg L⁻¹ IBA, respectively. Cuttings from Standard trees had intermediate rooting of 56 and 6% at 250 and 1250 mg L⁻¹ IBA, respectively. Pillar trees consistently grew more roots with greater root length per cutting than the other growth habits. It is proposed that differences in rooting response among the growth habits may be associated with differences in endogenous auxin concentration that had been found in previous studies. Within peach and possibly other fruit trees, the capacity of shoot cuttings to develop adventitious roots can vary by cultivar and successful root induction with exogenous plant growth regulators may depend, in part, on endogenous hormone levels.     

Effect of uric acid on the maturation and the biological function of BMDCs

AIM: To investigate the effect of uric acid on the maturation and the biological function of murine bone-marrow derived dendritic cells (BMDCs) in vitro.METHODS: BMDCs were cultured with GM-CSF, IL-4, LPS and uric acid. Cell phenotypes were analyzed by flow cytometry. MTT was used to detect the effect of uric acid on the function of BMDCs in stimulating the proliferation of T cells. IL-12 released by BMDCs was also detected. RESULTS: BMDCs were cultured and identified. Uric acid at concentrations of 200 mg/L and 400 mg/L increased the expression of the molecules (CD11c, CD83, CD86, IA/IE) on BMDCs surface and the IL-12 level in the culture supernatants (P<0.05), promoted the proliferation of T cells at the T: DC rate 5∶1, 10∶1, 20∶1 (P<0.05). However, uric acid at concentration of 70 mg/L had no effect on above molecule expression (P>0.05), no effect on T cell proliferation with BMDCs (P>0.05) was observed. CONCLUSION: Uric acid promotes the differentiation, maturation, the expression of co-stimulatory molecules, the IL-12 production in BMDCs and enhances the ability of BMDCs to stimulate the proliferation of T cell in a specical dose range.     

Effects of Shengmai San on oxidative damage in mentally stressed mice

AIM: To investigate the preventive effects of Shengmai San (SMS) on oxidative damage in mentally stressed mice.METHODS: An oxidative stress mouse model was established by moustache-removed. Protein carbonyl and thiobarbituric acid reactive substance (TBARS) formation were determined as the oxidative stress markers.RESULTS: (1)Moustache-cut was founded to significantly enhance the behavioral movements of mice, especially large movements (movement 2 and rearing). SMS pre-administration inhibited the accelerated movements. (2) Protein carbonyl was increased in brain, heart, liver and kidney. TBARS in liver and heart increased in the moustache-cut mice, but SMS pretreatment inhibited the increased protein carbonyl and TBARS.CONCLUSION: SMS has the preventive effects on oxidative damage induced by emotional stress.     

Improvements in somatic embryogenesis protocol in Feijoa (Acca sellowiana (Berg) Burret): Induction,conversion and synthetic seeds

Pineapple guava (Acca sellowiana) syn. Feijoa sellowiana, a Brazilian indigenous Myrtaceae is under domestication in South Brazil. Previous works showed that this species is responsive to somatic embryogenesis and recalcitrant to conventional methods of clonal propagation. In the present work it was evaluated the role of components of culture medium in the induction and development of somatic embryos. The technology of synthetic seeds was also evaluated. Zygotic embryos were inoculated in LPm medium supplemented with 8 mM glutamic acid and 8 mM l-glutamine, 2,4-dichlophenoxiacetic acid (20 μM) and myo-inositol. For conversion of somatic embryos and synthetic seeds it was tested the effect of 6-benzylaminopurine and gibberellic acid combined or not with activated charcoal. The highest values for embryogenetic induction (100%) and number of somatic embryos/explant (113) were observed in the LPm medium supplemented with Glu (8 mM), and 2,4-D. The culture medium supplemented with BA (0.5 μM) and GA₃ (1 μM) and activated charcoal (1.5 g L⁻¹) enhanced the conversion of somatic embryos to plantlets. Pre-germinated somatic embryos encapsulated in sodium alginate with BA (0.5 μM) and GA₃ (1 μM) developed radicles. The use of synthetic seed was a requisite for the survival of plantlets.     

Bacillus subtilis as an alternative biologically based strategy for controlling Fusarium wilt disease in tomato: A histological study

The employment of formulateBacillus subtilis as a biocontrol agent successfully controlledFusarium oxysporum f.sp.lycopersici within tomato seedlings (in vivo). B. subtilis was able to proted cortex and vascular tissues of tomato against progression of the wilt pathogen. No changes were observed in tomato tissues due to application ofB. subtilis except for hypertrophy and elongation of cortex tissues, which indicates the production of plant growth hormones byB. subtilis.     

<Emphasis Type="Italic">In vitro</Emphasis> screening for sunflower (<Emphasis Type="Italic">Helianthus annuus</Emphasis>L.) resistant calli to <Emphasis Type="Italic">Diaporthe helianthi</Emphasis> fungal culture filtrate

Diaporthe helianthi the causal agent of sunflower (Helianthus annuus) stem canker, causes significant reductions in yield and oil content in most sunflower-growing areas. With the aim of enhancing host resistance, we selected in vitro sunflower calli against culture filtrates of two pathogen isolates (7/96 and 101/96). This technique may be an effective and rapid tool to discriminate the most virulent D. helianthi isolate and to screen for host resistance in the early stage of a breeding programme. Further investigation on the mechanisms involved in defence pathways showed no induction of salicylic acid and pathogenesis-related proteins in calli, indicating that the host resistance is not associated with Systemic Acquired Resistance but probably other biochemical mechanisms.     

Molecular analysis of resistance mechanisms to Orobanche cumana in sunflower

Resistance to the dicotyledenous parasite Orobanche cumana in sunflower is characterized by a low number of parasitic attachments and a confinement of the parasite in host tissues leading to its necrosis. To help understand what determines such resistance mechanisms, molecular, biochemical and histological approaches were employed before (early response) and after (late response) attachment of the broomrape parasite to susceptible (2603) and resistant (LR1) sunflower genotypes. The expression patterns of 11 defence-related genes known to be involved in different metabolic pathways (phenylpropanoids, jasmonate, ethylene) and/or in resistance mechanisms against microorganisms were investigated. RT-PCR and cDNA blot experiments revealed that the resistant genotype exhibited a stronger overall defence response against O. cumana than the susceptible one, involving marker genes of the jasmonate (JA) and salicylic acid (SA) pathways. Among them, the SA-responsive gene, def. (defensin), appeared to be characteristic of LR1 sunflower resistance. However, no JA accumulation and similar SA contents (250–300 ng g⁻¹ FW) were measured by GC/MS in both genotypes, parasitized or not. In addition, three cDNAs, isolated by a suppression-subtractive hybridization, were shown to be strongly induced only in the resistant genotype 8 days post-inoculation, when the first O. cumana attachments occurred. These genes, putatively encoding a methionine synthase, a glutathione S-transferase and a quinone oxidoreductase, might be involved in detoxification of reactive oxygen species, suggesting the occurrence of an oxidative burst during the incompatible interaction. Finally, host cell-wall modifications leading to parasite-confinement were correlated with more intense callose depositions in the resistant genotype, concomitant with over-expression of the callose synthase cDNA HaGSL1 .