四川自贡中侏罗世峨眉龙—新种

记述了产自四川自贡大山铺中侏罗世峨眉龙属一新种——焦氏峨眉龙(Omeisaurus jiaoisp.nov.)。新种为大型蜥脚类恐龙,以如下特征区别于其他蜥脚类:前、中部背椎为典型的后凹型,后部背椎为双平型,背椎神经棘呈高大棒状,不分叉;尾椎为弱双凹型,第一尾椎不具扇形尾肋;第一脉弧短小且与第一尾椎关联;锁骨长大;肱骨和股骨细长而圆实;肱骨与股骨长度之比为0.83,尺骨与肱骨长度之比为0.72,胫骨与股骨长度之比为0.63。     

THE FLAGELLAR APPARATUS OF THE ZOOSPORE OF UROSPORA PENICILLIFORMIS(CHLOROPHYTA)1

The flagellar apparatus of Urospora penicilliformis (Roth) Aresch. is unique, or at least very unusual among green algae. The flagellar axonemes are rigid, and contain wing-like projections. There are no central microtubules in the most proximal part of the axoneme. The transition region contains a series of electron dense transverse lamellae rather than a single septum, and lacks a stellate pattern. There is no cartwheel pattern in the proximal part of the basal bodies. The latter are associated with four different types of fibrous elements: ascending striated fibers that attach to an electron dense plate in the papillar center, lateral striated fibers that parallel microtubular roots, fibrous elements that link adjacent basal bodies, and finally two massive striated fibers that descend into the cell, passing closely along the nucleus (system II fibers, or rhizoplasts). Each of the four microtubular flagellar roots is sandwiched between two system I striated structures. The roots are probably equal; they contain proximally four, and distally up to eight microtubules. Based on the zoospore flagellar apparatus, it is concluded that the multinucleate U. penicilliformis is related to the Ulvaphyceae. Finally, a possible explanation in functional terms is given for the peculiar external morphology and behavior of the zoospore.     

鳗鲡肝脏、脾脏显微与超微结构

经光镜和电镜观察发现：鳗鲡肝脏的肝小叶不规则。肝细胞胞质内富含多种细胞器及包含物。胆小管由２—４个肝细胞围成，相邻肝细胞间有连接复合体封闭胆小管。肝血窦为有孔型、孔处无隔膜，内有巨噬细胞。窦周隙明显，未见贮脂细胞。肝细胞向胆小管腔与窦周隙面伸出许多指状微绒毛。脾脏内白髓中淋巴细胞聚集成群，未见明显脾小结、淋巴鞘。红髓由脾索与脾窦组成，动脉分支末端（壁厚的毛细血管）可开放于红髓，无明显巨噬细胞中心。脾窦及脾小动脉内皮细胞通常为长杆状、沿血管纵向平行排列。脾窦为有孔型，孔处可见薄的隔膜。脾小动脉内皮外为２—５层平滑肌（多数为纵行）。     

VALVE AND BAND MORPHOLOGY OF SOME FRESHWATER DIATOMS. II. INTEGRATION OF VALVES AND BANDS IN NAVICULA CONFERVACEA VAR. CONFERVACEA12

Chemically cleaned and critical-point dried cells of a clonal culture were examined with scanning electron microscopy. Cells form filaments by valve-to-valve connections maintained by organic material which adheres to the central area of the valve face. Bending of filaments is probably restricted to some extent by the articulation of overlapping spatulate marginal spines with an adjacent underlapping set of much shorter spines (ridges), and with the mantle edge itself. Cell division results in three possible spine patterns for each cell: a set of overlapping and a set of underlapping spines; no overlapping sets of spines (two underlapping); or two sets of overlapping spines (no underlapping). Each filament inherits cells with spine set patterns in the ratio of 2 (with 1 set overlapping): 1 (with no sets overlapping): 1 (with 2 sets overlapping). Valvocopulae are shaped similarly to pleurae except that the partes exteriores of the valvocopulae are wider. The pars interior of both is delimited by an advalvar row of pores continuous around the cell apex. The pars exterior also has a row of pores, but it is median in the valvocopula and first pleura and does not continue around the cell apex. The valvocopulae always underlap the mantle and the pleurae always underlap their preceding band. The ends of both appeared attached, but may become free in acid-cleaned preparations. Bands alternate with each other so that the ends of the valvocopula attach to the first continuous apical portion of the first pleura; the ends of the first pleura attach in that same fashion to the second pleura but at the opposite apex; and all subsequent pleurae alternate in the same fashion with up to at least 13 pleurae/epicingulum. The continuous apical portion of each band is elevated so that a functional (but not structural) ligula is formed, with the continuous apical portion of alternate bands becoming adjacent and underlapping each other only in this region. The valvocopulae in a single cell, or of adjacent cells, may have their continuous apical ends on the same or on opposite apices. It is recommended that N. confervacea var. peregrina (W. Sm.) Grun. be merged with the nominate variety.     

SYNCHRONOUS GROWTH OF CHLAMYDOMONAS REINHARDTII (CHLOROPHYCEAE): A REVIEW OF OPTIMAL CONDITIONS1

Chlamydomonas reinhardtii Dangeard was synchronized at optimal growth conditions under a 12:4 LD regime at 35 C and 20,000 lx with serial dilution to a standard starting cell density of (1.4 ± 0.2) × 10⁶ cells/ml. Synchronous growth and division were characterized by measuring cell number, cell volume and size distribution, dry weight, protein, carbon, nitrogen, chlorophyll, carotenoids, nucleic acids, nuclear and cytoplasmic division during the vegetative life cycle. The main properties of the present system are: Exponential growth with high productivity, high degrees of synchrony and reproducibility during repeated life cycles. The degree of synchrony of this light-dark synchronization system was evaluated and compared with those described in the literature using probit analysis of the time course of DNA synthesis, nuclear and cytoplasmic division and sporulation (increase in cell number). The results showed that the degree of synchrony is highest for cells grown under optimal conditions.     

桉树LH22、U6无性系茎提取液对绿豆插条发根和种子萌发的影响

研究表明,难生根的尾叶桉×赤桉LH₂₂无性系茎的粗提液对绿豆插条发根率、不定根长度有极明显的抑制作用,而易生根的尾叶桉U₆无性系茎的粗提液却没有抑制作用。对这些茎粗提液进一步用有机溶剂萃取分离,各萃取相进行白菜种子萌发的生物测验,表明LH₂₂中的水相、乙醚相含有抑制种子萌发的物质,经Duncan's新复极差法分析抑制作用显著,而易生根的U₆中却无影响。水相、乙醚相分别再经硅胶柱层析技术分离纯化得到多种不同的成分,进行白菜种子萌发生物测验后,有数种成分有明显的抑制作用。因此说明,难生根的LH₂₂无性系茎内含有成分不同的生根抑制物质,而易生根的U₆无性系茎内几乎没有或含有少量这些生根抑制物质。     

In Vitro Amyloidogenic Peptides of Galectin-7: POSSIBLE MECHANISM OF AMYLOIDOGENESIS OF PRIMARY LOCALIZED CUTANEOUS AMYLOIDOSIS

Pathogenesis of primary localized cutaneous amyloidosis (PLCA) is unclear, but pathogenic relationship to keratinocyte apoptosis has been implicated. We have previously identified galectin-7, actin, and cytokeratins as the major constituents of PLCA. Determination of the amyloidogenetic potential of these proteins by thioflavin T (ThT) method demonstrated that galectin-7 molecule incubated at pH 2.0 was capable of binding to the dye, but failed to form amyloid fibrils. When a series of galectin-7 fragments containing β-strand peptides were prepared to compare their amyloidogenesis, Ser³¹-Gln⁶⁷ and Arg¹²⁰-Phe¹³⁶ were aggregated to form amyloid fibrils at pH 2.0. The rates of aggregation of Ser³¹-Gln⁶⁷ and Arg¹²⁰-Phe¹³⁶ were dose-dependent with maximal ThT levels after 3 and 48 h, respectively. Their synthetic analogs, Phe³³-Lys⁶⁵ and Leu¹²¹-Arg¹³⁴, which are both putative tryptic peptides, showed comparable amyloidogenesis. The addition of sonicated fibrous form of Ser³¹-Gln⁶⁷ or Phe³³-Lys⁶⁵ to monomeric Ser³¹-Gln⁶⁷ or Phe³³-Lys⁶⁵ solution, respectively, resulted in an increased rate of aggregation and extension of amyloid fibrils. Amyloidogenic potentials of Ser³¹-Gln⁶⁷ and Phe³³-Lys⁶⁵ were inhibited by actin and cytokeratin fragments, whereas those of Arg¹²⁰-Phe¹³⁶ and Leu¹²¹-Arg¹³⁴ were enhanced in the presence of Gly⁸⁴-Arg¹¹³, a putative tryptic peptide of galectin-7. Degraded fragments of the galectin-7 molecule produced by limited trypsin digestion, formed amyloid fibrils after incubation at pH 2.0. These results suggest that the tryptic peptides of galectin-7 released at neutral pH, may lead to amyloid fibril formation of PLCA in the intracellular acidified conditions during keratinocyte apoptosis via regulation by the galectin-7 peptide as well as actin and cytokeratins.     

MICROSENSOR MEASUREMENTS OF THE EXTERNAL AND INTERNAL MICROENVIRONMENT OF FUCUS VESICULOSUS (PHAEOPHYCEAE)1

We investigated the O₂, pH, and irradiance microenvironment in and around the tissue of the brown alga Fucus vesiculosus L. using microsensors. Microsensors are ideal tools for gaining new insights into what limits and controls macroalgal activity and growth at very fine spatial (<100 μm) and temporal (seconds) scales. This first microsensor investigation of a fucoid macroalga revealed differences in the microenvironment and metabolic activities at the level of different cell layers and thallus structures. F. vesiculosus responded quickly to rapid shifts in irradiance resulting in a highly dynamic microenvironment around and within its thallus. In combination with detailed morphological studies and molecular approaches, microsensors offer a promising toolbox to quantitatively describe structural and functional adaptations of macroalgae to environmental conditions, such as flow and light climate, as well as their physiological responses to environmental stressors.     

SORPTION OF PLUTONIUM-237 BY TWO SPECIES OF MARINE PHYTOPLANKTON11

The adsorption of plutonium-237, added from an acid solution, by two species of marine phytoplankton, Monochrysis lutheri Droop, a flagellated chrysomonad, and Phaeodactylum tricornutum Bohlin, a diatom, is governed by a passive mechanism. This is clearly indicated by the observation that the rapid rates of sorption were not significantly different for live and heat-killed cells incubated at 24°C and 0°C. The Q₁₀ values for the chrysomonad and the diatom of 0.95 and 1.18, respectively, are indicative of passive processes. The average ratio of (activity on algae/activity in filtrate) per unit volume at 24 h, the time when maximum levels of algal radioactivity were attained, of (32 ± 4) × 10³ was not significantly different for the diatom or the chrysomonad. On a per cell basis, maximum levels of radioactivity were attained within 2 h. Less than 20% of the adsorbed ²³⁷Pu desorbed after 24 h.     

MORPHOLOGY AND TAXONOMY OF HIMANTOTHALLUS (INCLUDING PHAEOGLOSSUM AND PHYLLOGIGAS), AN ANTARCTIC MEMBER OF THE DESMARESTIALES (PHAEOPHYCEAE)1

The sporophyte of Himantothallus develops according to a closed pattern in which the number and position of the blades is determined by the location of trichothallic meristems in a filamentous germling. Expansion of the miniature juvenile to the massive adult thallus is accomplished by diffuse secondary growth and involves a change from filamentous rhizoids to a hapteroid holdfast, flattening of the stipe, and enormous increases in length, breadth, and thickness of both stipe and blade. The axis usually bears 1–8 lateral blades, often paired, and terminates in a flattened stub. Phaeoglossum is interpreted as a growth form of Himantothallus in which a terminal blade develops to the exclusion of lateral blades, the latter being represented by a single spine. Phyllogigas clearly falls within the morphological spectrum of Himantothallus, the lack of twisting being related to physical factors in the environment. Sporangia, interspersed with an equal or somewhat larger number of two-celled paraphyses, are borne in slightly elevated sori scattered over both surfaces of the blade. Zoospore germination was not observed, nor were gametophytes, either in culture or in the field. Haptera apparently originate from the meristoderm in the lower part of the maturing stipe and lack a filamentous medulla. The mature stipe and the mature blade are anatomically similar, being composed of a superficial meristoderm, a cortex of parenchyma-like cells, and a filamentous medulla. The meristoderm is usually a single layer of plastid-containing cells that divide anticlinally to accommodate (or effect) expansion and periclinally to produce cortical tissue inward. Cortical cells are in radial files and increase in diameter towards the interior. They usually are densely packed with physodes. The medulla is uniquely distinguished by the presence of sheathed trumpet hyphae. Cells of the trumpet hyphae have perforate end walls with callose deposits and probably function in conduction as do the sieve filaments in Laminariales. Sheathing cells are filled with plastids. Sheathing filaments form connections among themselves and with nearby unsheathed filaments. The sheathed trumpet hyphae and their matrix of unsheathed filaments form a plexus, which in the mature blade is flattened and may be stripped intact from the other tissues. Development of the embryonic sporophyte is very similar to that in Desmarestia, as is the anatomy of the adult thallus and the sporangia. From these considerations, Himantothallus is assigned to the Desmarestiaceae (Desmarestiales).