中国东南高海拔黄山松生长对气候的响应——以浙江省九龙山和安徽省牯牛降为例

利用中国浙江省西南部九龙山自然保护区和安徽省南部牯牛降的高海拔黄山松树轮径向宽度资料,分别建立了2个树轮宽度差值年表(RES).由子样本信号强度(SSS)>0.8判定,九龙山年表(JLS01)的可靠时段为1884—2010年,牯牛降年表(GNJ01)的可靠时段为1837—2008年.将采样点周围气象站气象数据做算术平均代表区域气候状况,利用相关函数检验了两年表与区域气象数据的月降水量、月平均温度、月平均相对湿度、月总云量和月日照时数的关系.结果表明： 2个高海拔点树木径向生长主要受夏季(上年6、7月,当年6月)水热条件的影响.九龙山年表与上年6、7月温度呈显著正相关,与上年6、7月和当年6月降水及相对湿度呈显著负相关,与上年7月总云量呈显著负相关,与上年6、7月日照时数呈显著正相关;牯牛降年表与上年7月温度呈显著正相关,与上年7月和当年6月降水及相对湿度呈显著负相关,与上年6月总云量呈显著负相关,与上年7月、当年6月日照时数呈显著正相关.由于高海拔地区温度较低,夏季温度的升高有利于该地区树木生长,同时较多降水对应的高相对湿度、高云量和低日照时数,限制了光合作用产物的合成,导致树木的径向生长受到抑制.
     

混合添加乙醇和H2O2对嗜热子囊菌产过氧化氢酶的影响

在以嗜热子囊菌( T. aurantiacus WSH03-01BC)生产过氧化氢酶的7L罐发酵研 究中,发现混合添加适量的乙醇(75%)和H2O2可以促进菌体产酶.在发酵36h和 48h分别添加0.8%(v/v)的乙醇时,酶活比对照提高了34.3%;当添加乙醇的总量超过2.4 %时 ,对菌体的生长及产酶有明显的抑制作用;在发酵36～60h恒速流加1.6%的乙醇,CAT的酶活 达到2519U/mL,单位细胞产酶能力提高了47.3%;在发酵36h～60h恒速流加1.6%的乙醇并在4 8h混合添加0.4%的H2O2时,CAT的酶活达到2786U/mL,比对照提高了50.1% .     

Alpha-melanocyte stimulating hormone protects retinal pigment epithelium cells from oxidative stress through activation of melanocortin 1 receptor–Akt–mTOR signaling

Patients with age related macular degeneration (AMD) will develop vision loss in the center of the visual field. Reactive oxygen species (ROS)-mediated retinal pigment epithelium (RPE) cell apoptosis is an important contributor of AMD. In this study, we explored the pro-survival effect of α-melanocyte stimulating hormone (α-MSH) on oxidative stressed RPE cells. We found that α-MSH receptor melanocortin 1 receptor (MC1R) was functionally expressed in primary and transformed RPE cells. RPE cells were response to α-MSH stimulation. α-MSH activated Akt/mammalian target of rapamycin (mTOR) and Erk1/2 signalings in RPE cells, which were inhibited by MC1R siRNA knockdown. α-MSH protected RPE cells from hydrogen peroxide (H₂O₂)-induced apoptosis, an effect that was almost abolished when MC1R was depleted by siRNA. α-MSH-mediated S6K1 activation and pro-survival effect against H₂O₂ was inhibited by Akt inhibitors (perifosine, MK-2206 and LY294002). Further, mTOR inhibition by rapamycin, or by mTOR siRNA knockdown, diminished α-MSH’s pro-survival effect in RPE cells. Thus, Akt and its downstream mTOR signaling mediates α-MSH-induced survival in RPE cells. In summary, we have identified a new α-MSH–MC1R physiologic pathway that reduces H₂O₂-induced RPE cell damage, and might minimize the risk of developing AMD.     

产乙醇酸氧化酶的重组毕赤酵母的构建及催化合成乙醛酸的研究

乙醇酸氧化酶（Go）是植物光呼吸途径中的一种关键酶,可以催化乙醇酸生产乙醛酸。从新鲜菠菜叶中提取总RNA,利用RT-PCR技术获得编码GO基因的cDNA片断。通过基因重组将GO基因克隆到载体pA0815中,构建了胞内表达载体pA0815／GO,重组质粒经电转整合至甲醇营养酵母GS115染色体。在混合碳源为10g/L山梨醇和0．5g/L甲醇的培养条件下,细胞的GO酶活达到474IU／g（DCW）。利用该重组毕赤酵母作为催化剂生产乙醛酸,结果表明：在乙醇酸浓度为0．25mol／L,重组酵母湿菌体为10dL,黄素单核苷酸（FMN）浓度为0．01mmol／L,pH8．0,20℃,反应18h后乙醛酸的产率达到51．8％。     

Stress-induced RNASET2 overexpression mediates melanocyte apoptosis via the TRAF2 pathway in vitro

The recent genome-wide association study identified a link between vitiligo and genetic variants in the ribonuclease T2 (RNASET2) gene; however, the functional roles of RNASET2 in vitiligo pathogenesis or in melanocyte apoptosis have yet to be determined. The current study was designed to investigate the vitiligo-related expression pattern of RNASET2 and its molecular function involving apoptosis-related signaling proteins and pathways. The results showed overexpression of RNASET2 in epidermis specimens from 40 vitiligo patients compared with that from matched healthy controls. In addition, in vitro analyses indicated that overexpression of RNASET2 was inducible in cultured primary human melanocytes and keratinocytes by stress conditions, that is, exposure to UV irradiation, hydrogen peroxide, and inflammatory factors, respectively, and led to increased cell apoptosis via the tumor necrosis factor receptor-associated factor 2 (TRAF2)–caspases pathway through the physical interaction of RNASET2 with TRAF2. Thus, RNASET2 may contribute to vitiligo pathogenesis by inhibiting TRAF2 expression and, as such, RNASET2 may represent a potential therapeutic target of vitiligo.     

RETRACTED ARTICLE: Circ-NUP214 Promotes Papillary Thyroid Carcinoma Tumorigenesis by Regulating HK2 Expression Through miR-15a-5p

Biochemical Genetics -     

中国莽人、僜人、珞巴族与门巴族Heath-Carter法体型研究

作者于2006—2007年在云南、西藏调查了中国莽人、僜人、珞巴族、门巴族体重、身高、上臂收缩围、小腿围、肱骨内外上髁间径、股骨内外上髁间径、肱三头肌位皮褶、肩胛下位皮褶、髂前上棘位皮褶和腓肠肌位皮褶10项指标值,计算了4个族群的Heath-Carter法体型值。研究结果显示: 1)在南方族群中, 莽人身矮体轻, 身体细瘦, 皮脂菲薄, 肌肉不发达。僜人身矮体轻, 身体细瘦, 男性肌肉较发达, 皮脂厚度中等。女性肌肉发达, 皮脂厚。珞巴族与门巴族均身材高, 体重大, 身体粗壮, 皮脂厚, 肌肉发达。2)门巴族男性为偏内胚层的中胚层体型, 莽人、僜人、珞巴族男性为均衡的中胚层体型。僜人、珞巴族、门巴族女性为偏中胚层的内胚层体型, 莽人女性为偏内胚层的中胚层体型。莽人、僜人、珞巴族男性具有南亚类型族群的体型特征, 门巴族男性具有北亚类型族群体型特征。莽人女性具有南亚类型族群的体型特征, 僜人、珞巴族、门巴族女性具有北亚类型族群的体型特征。     

Greater soil microbial biomass loss at low frequency of N addition in an Inner Mongolia grassland

低频率的氮添加使内蒙古草原土壤微生物生物量碳出现更大幅度下降 土壤微生物生物量在生物地球化学循环过程中至关重要,是土壤碳固持的前体物质。人为氮输入深刻地改变了草地土壤微生物生物量。然而,传统氮沉降模拟实验仅通过低频率的氮添加进行,与持续高频率的自然氮沉降相比,对土壤微生物生物量的影响可能存在差异。不同频率的氮添加对土壤微生物生物量的影响尚缺乏可靠的数据支撑。本研究通过在不同的氮添加速率(0–50 g N m−2 yr−1)下,控制氮添加频率(每年2次和12次),研究了土壤微生物生物量碳对不同氮添加频率的响应。研究结果表明,在两种氮添加频率下,随着施氮水平的提高,土壤微生物生物量碳逐渐降低。然而,在低施氮频率下,土壤微生物生物量的下降幅度更大,这说明传统的氮添加实验可能高估了氮沉降对土壤微生物生物量的影响。在低施氮频率下,土壤酸化、无机氮积累、碳氮失衡、地下净初级生产力分配减少和真菌细菌比例降低等情况加剧,导致微生物生物量出现较大幅度下降。在未来研究中,为可靠预测氮沉降对草地生态系统土壤微生物功能和碳循环的影响,不仅要考虑氮添加的剂量,还需要考虑氮添加的频率。