Dictyoclostus cf.neoinflatus Licharew的拟内疹

有铰纲腕足动物的壳壁疹孔,具有分类及生态方面的意义。十九世纪中叶,M.D.Carpenter(1853)用光学显微镜,观察了穿孔贝类的壳壁穿孔。以后,K.M.Hatai(1940)、P.E.Cloud(1942)以及A.Williams(1956,1965)等,对此类构造均作过描述,并称之为内疹(Endopuncta)。1968年Williams利用电子显微镜,研究了现代穿孔贝内疹的超微形态,并对其成因和功能作了较详细的探讨。     

Production of fertile somatic hybrids of Gossypium hirsutum?+?G. bickii and G. hirsutum?+?G. stockii via protoplast fusion

Fertile somatic hybrids were obtained via symmetric electrofusion of protoplasts from two combinations of tetraploid cotton (G. hirsutum cv. Coker 201, AD genome) and diploid wild cottons G. bickii (G genome) and G. stockii (E genome), respectively. Observation by morphological, flow cytometric analysis, chromosome counting and RAPD analysis of the tested hybrids of Coker 201 + G. bickii and Coker 201 + G. stockii confirmed the regenerated plants as hybrid status. Cytological investigation of the metaphase root-tip cells revealed there were 78 chromosomes in the hybrids. Flow cytometric analysis showed the tested plants had a relative DNA contents close to the total DNA contents of the two parents. RAPD analysis revealed the hybrids contained specific genomic fragments from both fusion partners, further confirmed their hybridity. The morphology of the hybrids was intermediate between the two fusion partners. The hybrid plants were successfully transferred to the soil, and they bloomed and set bolls. It is sure that the new hexaploids developed by cell fusion would contribute to cotton breeding through backcrossing with the elite genotypes of G. hirsutum.     

Photosynthesis of Ulva sp. II. utilization of CO2 and HCO−3 when submerged

The photosynthetic capacity of submerged Ulva sp. when utilizing CO₂ and HCO^?₃ as exogenous carbon forms has been investigated and compared with ambient carbon concentrations in sea water. Saturating concentrations of HCO^{? ₃} and CO₂ were 1200 and 100 μM, respectively at saturating light, and photosynthetic rates under such conditions averaged 700 μmolO₂·gDW^?1 ·h^?1. The HCO^?₃ concentration of sea water (≈2500μM), was thus found to be saturating for photosynthesis of Ulva. At the CO₂ concentration of sea water (≈ 10 μM), the contribution of this carbon form to photosynthesis could be 27% at the most. Under conditions of slow water movement, the relative importance of CO₂ utilization would probably be minimized in favour of HCO^?₃ utilization. It is concluded that HCO^?₃ uptake is not limiting photosynthesis for Ulva under natural conditions.     

Secondary structures of peptides: 5 · 15N n.m.r. CP/MAS spectroscopy of solid polypeptides and gramicidin-S

30.5 MHz ¹⁵N m.m.r. (CP/MAS) spectra of various solid polypeptides were measured using the cross-polarization/magic angle spinning technique. In order to obtain optimum signal-to-noise ratios, relatively short contact times (1 ± 0.5 ms) are required, because the cross-polarization times (T_NH) are short and because the proton rotating-frame relaxation times (T_1p) are in the order of 20 ms. The ¹⁵N n.m.r. signals of copolypeptides may be sensitive to sequence effects; yet they are in most cases more sensitive to the nature of the secondary structure. The signals of α-helices absorb ca. 8–10 ppm upfield of β-sheet structures, whereas the polyglycine II helix absorbs downfield. The natural abundance spectrum of crystalline gramicidin-S exhibits a signal at ?247 ppm, a characteristic chemical shift of the antiparallel pleated sheet structure.     

云南澄江早寒武世蠕虫化石——Maotianshania gen.nov.

1984—1985年,侯先光曾几次赴云南考察,在澄江县帽天山(24°39′N,102°57′E)下寒武统筇竹寺组玉案山段下部,发现了一大批门类众多保存精美的后生动物化石,其中包括海绵、水母、蠕虫、软舌螺、腕足类、腹足类、金臂虫、三叶虫以及其它节肢动物等。这个以含有大量的软体后生动物的新化石组合,已被命名为“澄江动物群”(张文堂、侯先光,1985)。根据伴生的三叶虫化石,澄江动物群的层位为早寒武世筇竹寺组Eoredlichia-Wutingaspis带下部,距今大约为570百万年,略新于前寒武纪-寒武纪过渡期的梅树村阶(见孙卫国、侯先光,1987,表I)。澄江动物群中的蠕虫化石数量十分丰富,     

桂林附近的Amphipora sp.及其生态

达尔文在“物种起源”一书中指出:不同生物起源于少数共同的祖先,原始种类在自然选择作用下,不断分化为性状差异的新种。由于生物分枝演化的结果,导致更高分类单位属、科、目、纲、门的形成。这一正确的物种形成原理与对生物谱系的描绘,已普遍地为生物学家所接受,并依此而建立了反映生物演进与亲缘关系的生物系统分类。古生物学分类与现代生物学分类的原理基本上是一致的,由于它的研究对象是地史时期中的生物,现在不能对其生活期间的完整形态、生理、生态等进行直接观察研究。因此,它们之间还是有所差别的。     

Govindjee, Fork, D.C.: Charles Stacy French 1907–1985 National Academy of Sciences, Washington 2006. 28 pp.

Book Reviews

Govindjee, Fork, D.C.: Charles Stacy French 1907–1985 National Academy of Sciences, Washington 2006. 28 pp.     

江苏句容下二叠统腹足类新种Euomphalus gigantonodus sp.nov.

本文记述一个腹足类新种。Euomphalus gigantonodus sp.nov.,采自江苏句容船山的下二叠统黑色页岩中;产腹足类化石的岩层之上的灰岩产(竹蜓)Misellina claudiae,之下的灰岩产Sphaeroschwagerina。腹足类新种共有三个标本,均稍受挤压。     

B.t.c. cry1C全长基因的克隆及其在增产菌中的表达*

设计的一对引物 ,对苏云金芽孢杆菌科默尔亚种 (Bacillusthuringiensissubsp .colmeri)1 5A3菌株中的cry1C基因进行PCR扩增 ,得到包括结构基因 ,调节基因在内的全长为40kb的PCR产物。经两步克隆 ,将此基因连接至穿梭表达载体pHT315上 ,得到重组质粒pHT 1C。通过电转化将其导入一株增产菌蜡状芽孢杆菌 (Bacilluscereus) 9509菌株 ,SDS-PAGE检测到 1条 60kD左右的蛋     

Spectroscopic properties of ironthiosemicarbazone compounds. Structure of [Fe(C7H7N4S)2]·1.25H2O

The reaction of FeCl₃ and HL, where HL=C₇H₈N₄S, pyridine-2-carbaldehyde thiosemicarbazone, at physiological pH values in air gives rise to a powder of composition C₁₄H₁₆Cl_0.3FeN₈O_1.2S₂ which contains iron(II)- and iron(III)-thiosemicarbazone species. This fact confirms the reducing character of the ligand in neutral and basic media. The [Fe(C₇H₇N₄S)₂]·1.25H₂O compound has been isolated. The crystal structure consists of discrete monomeric cationic entities containing low-spin iron(II) ions in a distorted octahedral environment. The metal ion is bonded to one sulfur and two nitrogen atoms of each thiosemicarbazone molecule. The powdered X-band EPR spectra of C₁₄H₁₆Cl_0.3FeN₈O_1.2S₂ show a significant variation with temperature which can be explained considering an ‘exchange narrowing’ phenomenon, in good accordance with the presence of antiferromagnetic interactions. The Mössbauer measurements are in good agreement with the existence of one iron(II) and two iron(III) low-spin species, with relative areas of 69, 17 and 14%, respectively.     

中国枝孢属研究XXVI.*

本文报道枝孢属Cladosporium 的二个新种: 忍冬生枝孢C. lonicericola和山菅兰生枝孢C. dianellicola。新种提供了拉丁文简介、中文描述及形态图。模式标本收藏于云南农业大学真菌标本室(MHYAU)。     

中国枝孢属研究XXVII.*

本文报道枝孢属Cladosporium Link: Fries 的二个新种: 柚木生枝孢C. tectonicola 和莴苣生枝孢C. lactucicola。模式标本收藏于云南农业大学真菌标本室(MHYAU)。     

Macropolyhedral boron-containing cluster chemistry: two-electron variations in intercluster bonding intimacy. Contrasting structures of 19-vertex [(η-C5Me5)HIrB18H19(PHPh2)] and [(η-C5Me5)IrB18H18(PH2Ph)]

Fused double-cluster [(η⁵-C₅Me₅)IrB₁₈H₁₈(PH₂Ph)] (8), from syn-[(η⁵-C₅Me₅)IrB₁₈H₂₀] (1) and PH₂Ph, retains the three-atoms-in-common cluster fusion intimacy of 1, in contrast to [(η⁵-C₅Me₅)HIrB₁₈H₁₉(PHPh₂)] (6), from PHPh₂ with 1, which exhibits an opening to a two atoms-in-common cluster fusion intimacy. Compound 8 forms via spontaneous dihydrogen loss from its precursor [(η⁵-C₅Me₅)HIrB₁₈H₁₉(PH₂Ph)] (7), which has two-atoms-in-common cluster-fusion intimacy and is structurally analogous to 6.