A specimen of Curculioninae (Curculionidae,Coleoptera) from the Lower Cretaceous,Araripe Basin,north‐eastern Brazil

Abstract: A specimen of Curculionidae (Curculioninae) is described as Arariperhinus monnei gen. et sp. nov. The specimen is preserved on a laminated limestone sample of the Crato Formation (Santana Group), Lower Cretaceous (Aptian–Albian), and was collected from a quarry near Nova Olinda, Chapada do Araripe, State of Ceará, Brazil. The genus is placed in the subfamily Curculioninae because of its strongly convex body and relatively slender rostrum, but mainly by its rounded eyes and lack of a prosternal sulcus and tibial spurs. The very prominent eyes in lateral view, a cylindrical rostrum and a straight posterior margin of ventrite II are strong indications that this fossil belongs to the tribe Anthonomini. However, the claws, which would resolve the exact placement of this fossil, are poorly preserved. Arariperhinus monnei gen. et sp. nov. is distinguishable by the combination of several characters and the first record of the family Curculionidae in the Santana Group; it is the oldest record of a member of the subfamily Curculioninae.     

Moderate heat stress reduces the pH component of the transthylakoid proton motive force in light-adapted, intact tobacco leaves

We measured the Δ Ψ and ΔpH components of the transthylakoid proton motive force ( pmf ) in light-adapted, intact tobacco leaves in response to moderate heat. The Δ Ψ causes an electrochromic shift (ECS) in carotenoid absorbance spectra. The light–dark difference spectrum has a peak at 518 nm and the two components of the pmf were separated by following the ECS for 25 s after turning the light off. The ECS signal was deconvoluted by subtracting the effects of zeaxanthin formation (peak at 505 nm) and the qE-related absorbance changes (peak at 535 nm) from a signal measured at 520 nm. Heat reduced ΔpH while Δ Ψ slightly increased. Elevated temperature accelerated ECS decay kinetics likely reflecting heat-induced increases in proton conductance and ion movement. Energy-dependent quenching (qE) was reduced by heat. However, the reduction of qE was less than expected given the loss of ΔpH. Zeaxanthin did not increase with heat in light-adapted leaves but it was higher than would be predicted given the reduced ΔpH found at high temperature. The results indicate that moderate heat stress can have very large effects on thylakoid reactions.     

The Ultrastructure of Brood Pouch Formation in Tokophrya infusionum

SYNOPSIS Asexual reproduction in Tokophrya infusionum is by internal budding, whereby a ciliated, motile embryo is formed inside the sessile, non-ciliated parent in a specialized structure, the brood pouch. The process of embryogenesis and brood pouch formation was studied with the electron microscope using synchronized cultures. Reproduction begins with invagination of the pellicle and plasma membrane in the apical region of the adult. Early invagination is characterized by the presence of numerous microtubules beneath the plasma membrane or epiplasmic layer of the invaginating membranes. These microtubules apparently are important in formation of the brood pouch for colchicine blocks embryogenesis during the early stages. When the embryo is completed, it is ejected from the brood pouch thru the birth pore, an opening which is the site of the initial invagination and is present thruout embryogenesis. Theories of brood pouch formation are reviewed and discussed in light of the present investigation.     

TREATMENT OF AN INDIAN WOMAN WITH MAJOR DEPRESSION BY A LATINA THERAPTIS: CULTURAL FORMULATION

Culture, Medicine, and Psychiatry -     

The Fine Structure of Trophozoites and Gametocytes in Plasmodium coatneyi*

SYNOPSIS. An electron microscope study of Plasmodium coatneyi in the rhesus monkey supplied information on the fine structure of trophozoites, gametocytes and of the host cell. The trophozoites resemble other mammalian malaria parasites. They do not have typical protozoan mitochondria, but instead a concentric double-membraned organelle, which, it is assumed, performs mitochondrial functions. They feed on the host cell by pinocytosis, engulfing droplets of erythrocytes thru invaginations of the plasma membranes at any region of the cell or thru the cytostome. Digestion of hemoglobin takes place in small vesicles pinched off from the food vacuole proper. Gametocytes can be clearly distinguished into macro- and microgametocytes. Macrogametocytes are covered by 2 plasma membranes, the inner one appearing thicker in some places. The cytoplasm is filled with Palade's particles and has numerous vesicles of endoplasmic reticulum and toxonemes. In microgametocytes most of the inner membrane is thickened, the cytoplasm has few Palade's particles and vesicles of the endoplasmic reticulum and does not have toxonemes. Erythrocytes with trophozoites are irregularly scallop-shaped and have elevated points with knob-like protrusions covered by a double membrane. If these protrusions are sticky they might be in part responsible for clumping and arresting the schizonts and segmenters in the capillaries. The host cell contains numerous Maurer's clefts which in some instances are continuous with the membranes of the parasite suggesting that they might originate from them.     

Determination of Microgram Quantities of Stevioside from Leaves of Stevia rebaudiana Bert. by Two-Dimensional Thin Layer Chromatography

A method is described for the determination of stevioside fromleaves of Stevia rebaudiana Bert. Separation upon non-activatedsilica gel impregnated with boric acid in a two-dimensionalchromatographic system followed by clution and colorimetricassay is reported. Recuperation from chromoplates is over 95%.The observed ratio of the optical density of glucose: steviosidematches that expected theoretically so that glucose may be employedas a standard where pure stevioside is not available. Effects of the plant growth retardant, ancymidol, on the growthand morphology of the shoot system of cucumber (Cucumis sativusL. ) were investigated. Ancymidol inhibited stem elongation,reducing both number and length of internodes. Reduction inleaf area, attributable to a reduction in both cell size andnumber, was accompanied by an increase in chlorophyll per unitarea. The retardant decreased apical dominance and delayed anthesis.Gibberellic acid fully reversed ancymidol-induced inhibitionof stem elongation, internode length and production, and leafexpansion. GA_4/7 and ancymidol gave a synergistic promotionof stem elongation by increasing elongation of younger internodesand increasing internode production. Synergistic promotion ofpetiole elongation by this combination was also observed. Ancymidol,applied 7 d previously either to the shoot or root, severelyreduced the level of gibberellin-like activity in bleeding sapcollected from decapitated plants.     

Unusual Structures in the Flagellar Apparatus of a Strain of Trypanosoma cruzi*

Certain structures, associated with the flagellum, and which had hitherto been described as appearing occasionally in some species of trypanosomes, were found very frequently in epimastigote forms of strain F of Trypanosoma cruzi: (a) a group of tubular elements in an electron-dense mass enclosed within a swelling of the flagellar membrane as the flagellum emerges from its reservoir; (b) an expansion of the flagellar membrane at the point of the above swelling, which in cross-sections appears as a ring; and (c) an electron dense band in the body of the organism alongside the border of the flagellar pocket. The possible significance of these structures and the fact that so far they have been found only in one strain of T. cruzi are discussed.     

Variations in the Lengths of Fusiform Cambial Cells and Vessel Elements in Kalopanax pictus

Samples of a mature specimen of Kalopanax pictus, a ring-poroushardwood, were studied to compare the respective lengths offusiform cambial cells and vessel elements in the stem. Thelengths of dormant and reactivated fusiform cambial cells weremeasured with a confocal laser scanning microscope in tissuethat had been macerated by digestion with pectinase and in thicktangential sections. The lengths of early wood and late woodvessel elements were measured in tissues that had been maceratedby Franklin's method. The vessel elements and fusiform cambialcells varied considerably in length within individual samples.The mean length of early wood vessel elements corresponded tothat of fusiform cells in the dormant cambium but not in thereactivated cambium. Significant differences were observed betweenthe mean lengths of dormant and reactivated fusiform cambialcells, between those of reactivated fusiform cambial cells andearly wood vessel elements, between those of reactivated fusiformcambial cells and late wood vessel elements, and between thoseof early wood and late wood vessel elements. The frequency distributionsof lengths of cambial cells were bimodal and differed from thoseof vessel elements, which more closely resembled a normal distribution.The proportion of shorter lengths was higher in the reactivatedcambium than in the dormant cambium, the early wood and thelate wood vessel elements. Our results do not suppot the hypothesisthat the lengths of early wood vessel elements in ring-poroushardwoods change during differentiation. The similar rangesof recorded lengths suggest that short and long vessel elementsmight be derived directly from short and long cambial cells,respectively. Copyright 1999 Annals of Botany Company Kalopanax pictus, cambium, vessel element, confocal laser scanning microscopy, maceration, cell length.