Phytochemical Characterization and Biological Activities of a Hydroalcoholic Extract Obtained from the Aerial Parts of Matthiola incana (L.) R.Br. subsp. incana (Brassicaceae) Growing Wild in Sicily (Italy)

This study aimed to characterize the phenolic and the volatile constituents and to establish the antioxidant potential and the toxicity of a hydroalcoholic extract obtained from the leaves and flower buds of Matthiola incana (L.) R.Br. subsp. incana growing wild in Sicily (Italy). By HPLC‐PDA/ESI‐MS analysis, 12 phenolics (two phenolic acid derivatives and ten flavonoids) were identified, and eight of them were reported for the first time; luteolin‐glucoside was the main component (57.07 mg/g±0.87 % RSD). By SPME‐GC/MS, 47 volatile constituents were fully characterized, and dimethyl trisulfide turned out to be the most abundant one (33.24 %). The extract showed moderate activity both in the DPPH and in the reducing power assays (IC₅₀=2.32±0.24 mg/mL; ASE/mL=12.29±0.42); it did not inhibit the lipid peroxidation, whereas it was found to possess good chelating properties reaching approximately 90 % activity at the highest tested dose. Moreover, the extract protected growth and survival from H₂O₂‐induced oxidative stress in Escherichia coli. Finally, the extract was non‐toxic against Artemia salina (LC₅₀>1000 μg/mL). These findings increase the knowledge of M. incana subsp. incana and they could be helpful to a chemosystematic distinguishing of this subspecies also demonstrating that the aerial parts represent a safe source of antioxidants.     

The development of the brine shrimp Artemia salina (L.): a morphometric approach

Growth allomentry in the development of the brine shrimp Artemia salina (L.) was studied. Body width and abdomen length show a negative allometric relation to body length ( k =0.35 and 0.72 respectively) over th eight instars studied. Antennule length shows a negative allometric relation in respect to body length, with a change in the value of the growth constant at Instar Five from 0.31 to 0.75. Thoracic limb length shows a high positive relation to body length ( k =3.0) until Instar Six, when a negative allometric phase ( k =0.4) follows. A change in the sign of the growth constant from positive ( k =0.45) to negative ( k =-1.4) is noted for the length of the 2nd antenna in relation to body length.     

Mixture design as a potential tool in modeling the effect of light wavelength on Dunaliella salina cultivation: an alternative solution to increase microalgae lipid productivity for biodiesel production

Abstract

For a feasible microalgae biodiesel, increasing lipid productivity is a key parameter. An important cultivation parameter is light wavelength (λ). It can affect microalgal growth, lipid yield, and fatty acid composition. In the current study, the mixture design was used as an alternative to model the influence of the λ on the Dunaliella salina lipid productivity. The illumination was considered to be the mixture of different λ (the light colors blue, red, and green). All experiments were performed with and without sodium acetate (4?g/L), as carbon source, allowing the identification of the impact of the cultivation regimen (autotrophic or mixotrophic). Without sodium acetate, the highest lipid productivity was obtained using blue and red light. The use of mixotrophic cultivations significantly enhanced the results. The optimum obtained result was mixotrophic cultivation under 65% blue and 35% green light, resulting in biomass productivity of 105.06 mgL^?1day^?1, a lipid productivity of 53.47 mgL^?1day^?1, and lipid content of 50.89%. The main fatty acids of the oil obtained in this cultivation were oleic acid (36.52%) and palmitic acid (18.31%).     

葡萄糖对杜氏盐藻3-磷酸甘油脱氢酶活性的影响

杜氏盐藻是一种抗渗透能力强的单细胞绿藻,甘油在其渗透调节过程中具有重要作用。葡萄糖对杜氏盐藻细胞数量的增加效果不明显,但对盐藻细胞内甘油积累有显著促进作用,在0～15g/L范围内葡萄糖的浓度与胞内甘油积累显著相关(R2=0.9604,P=0.01);葡萄糖浓度达到15g/L时,胞内甘油积累量达到最高值7.80pg/cell,是对照的1.88倍,胞内甘油积累量与葡萄糖的消耗量极显著相关(R2=0.9982,P=0.01)。葡萄糖对盐藻细胞内总蛋白、3-磷酸甘油脱氢酶(GPDH)酶活和比活都有显著影响,在15g/L葡萄糖时这3个值达到最大值,分别是对照的1.354、4.384、3.229倍。数据显示葡萄糖浓度在15g/L时细胞内蛋白质含量增加不多,但GPDH酶活和比活却大幅度增加;葡萄糖导致的渗透压的变化可能诱导新的同功酶的合成。     

作物数量遗传学基础 二、遗传力及其估算

两栖类染色体的研究,过去多使用以生殖 细胞和端蚌尾部上皮细胞为材料的水低渗压片 法^[6]。然而,生殖细胞和峪蚌组织受季节的限 制颇大,所得的中期分裂相亦不甚多。随着 低等脊稚动物组织培养技术^[1,2]与血液培养技 术^[3]的发展,近年来已更多的使用离体培养的 细胞来进行研究。     

盐生杜氏藻对盐度改变的生理响应

以盐生杜氏藻为实验材料,采用f/2培养基,设置了8个盐度(15、20、25、30、50、70、90、110)处理,分盐度改变前(A)和盐度改变后(B)两个实验阶段,研究了盐生杜氏藻在不同盐度处理下的生长情况,测定了藻液的OD值、叶绿素a、β-胡萝卜素、可溶性蛋白质和可溶性糖含量等指标。结果表明,A阶段,几个较低盐度(15、20、25和30)处理生长状况较好,其中又以盐度20的处理最好;余下的处理,盐度越高,其生长所受的影响越大。B阶段,盐生杜氏藻的生长进入平台期后,50、70、90、110几个盐度较高处理的细胞密度、叶绿素a、β-胡萝卜素含量均显著超过了作为对照的盐度20的处理。且B阶段末期,先前盐度15的处理蛋白质、糖的积累量,与A阶段末期相比都有了不同程度的增加,而其余盐度处理组的蛋白质、糖含量则分别产生了不同程度的下降。     

杜氏盐藻叶绿体atpA基因片段的克隆及序列分析

根据莱因衣藻、卵形肾藻、普通小球藻等10种藻类的atpA全基因氨基酸高度保守序列,设计简并引物,利用PCR方法从盐藻叶绿体DNA中扩增出约400bp的片段,将该片段连接到T-vector上进行序列测定。结果表明,核苷酸长度为405bp,编码135个氨基酸。推导的氨基酸序列与莱因衣藻的同源性为92%,普通小球藻88%,Mesostigmaviride87%,卵形肾藻86%,Cyanidioschyzonmerolae85%。以所克隆的DNA片段为探针,与盐藻叶绿体基因组进行SouthernBlot杂交结果有明显的杂交信号。据此可推断本实验中所克隆的序列为杜氏盐藻叶绿体atpA基因片段。该基因序列已被GenBank收录,接受号为AY435096。     

Abstracts of papers read at the winter meeting at University College,London 2–4 January 1974

Dermocorynus montagnei Crouan frat., a red seaweed previously known only from a few dredged specimens collected in the Bretagne region of France, mostly in the last century, has been found growing subtidally on small stones at two sites in Galway Bay. Tetrasporangial and cystocarpic plants are present during most of the year and an account of the structure and development of these is given. It is concluded from these studies that Dermocorynus Crouan frat. is correctly placed in the Halymeniaceae Bory (=Cryptonemiaceae Harv.) and is best characterized generically by its unusual habit rather than by any of its reproductive characters. Culture studies show that the species has a Polysiphonia-type life history.     

杜氏盐藻psaB基因cDNA克隆及系统进化分析

根据真核生物莱茵衣藻(Chlamydomonas reinhardtii)、Chlamydomonas moewusii及Chlorella vulgaris等光系统Ⅰ反应中心蛋白psaB基因的氨基酸高度保守序列,设计一对简并引物,利用TRIzol试剂提取杜氏盐藻(Dunaliella salina)细胞的总RNA,通过RT-PCR,得到的一段长为1.8kb左右的cDNA片段。PCR产物经T-A克隆并测序以及测序结果推导成氨基酸序列进行同源性比较,表明所克隆的1815bp序列为杜氏盐藻光系统Ⅰ反应中心psaB基因的cDNA片段,GenBank收录号为AY820754。根据已经得到的psaB的核苷酸序列推导成氨基酸序列与一些已知物种的psaB氨基酸序列相比较,同源性分别为Chlamydomonas reinhardtii 92%,Chlamydomonas moewusii 91%,Chlorella vulgaris 86%,Mesostigma viride 85%,Phy -scomitrella patenssubsp.Patens 85%,Nephroselmis olivacea 84%。此外,psaB密码子偏爱性分析表明:杜氏盐藻psaB基因第三位密码子A和T的组成分别为35.7%和39.17%,而G和C分别为7.27%和17.85%,即杜氏盐藻psaB基因密码子的组成大多为NNA和NNT。根据psaB基因的特征,作者对绿藻门的50个物种的psaB基因作了进化分析,结果表明:杜氏盐藻与Haematococcaceae中的大多数种类进化地位最为接近,这为更进一步弄清杜氏盐藻的遗传背景提供了理论依据。