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21.
Abstract.  Contrary to current assumptions, the reflex blood of two-spot ladybirds, Adalia bipunctata , and seven-spot ladybirds, Coccinella septempunctata , contains haemocyte-like cells. Furthermore, DNA can be extracted and amplified from coccinellid reflex blood, confirming the presence of haemocyte-like cells and demonstrating a nondestructive method of DNA extraction.  相似文献   
22.
The members of the family Syngnathidae stand out among the bony fish for their specific parental care: the male bear embryos in a particular brood chamber or pouch. The physiological role of the latter is discussed in the literature in detail. The pouch is rather multifunctional; its osmoregulatory function is the most well studied. The unusual parental care supposes that some specific features should exist in the reproduction biology and development in these fish. This idea is supported by detailed studies of the ovaries and oogenesis in pipefish. On the other hand, the structure of the testes and specific features of spermatogenesis in the representatives of the family Syngnathidae remain poorly studied. The interest in the reproduction and development of pipefish is also determined, to a certain degree, by the fact that in the countries of Southeast Asia seahorses are objects of fishing and are used as a source of pharmacological materials comprising active compounds. Attempts to cultivate these fish have also been undertaken in these countries [13].  相似文献   
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Abstract. 1. Clip cages have been used widely by experimental ecologists to contain insects on plants.
2. Under controlled conditions, the effect of applying clip cages alone and clip cages and the chrysomelid beetle Gastrophysa viridula on systemic leaf expansion of Rumex obtusifolius was investigated. Treatments were applied to the fully expanded fourth leaf and expansion of leaf 8 was measured over a period of 22 days.
3. The application of clip cages reduced the rate at which leaf area increased and led to reductions in final leaf areas.
4. Clip cages have systemic effects on plant development and these effects are sustained even after the clip cage is removed. Investigators should take this into account in designing experiments.  相似文献   
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Book Reviews     
Book reviewed in this article:
Applied Anthropology: The Aboriginal Arts and Crafts Industry . Jon Altman
Marketing Aboriginal Art in the 1990s . Jon Altman and Luke Taylor  相似文献   
27.
The Caenorhabditis elegans genome contains three rac-like genes, ced-10, mig-2, and rac-2. We report that ced-10, mig-2 and rac-2 act redundantly in axon pathfinding: inactivating one gene had little effect, but inactivating two or more genes perturbed both axon outgrowth and guidance. mig-2 and ced-10 also have redundant functions in some cell migrations. By contrast, ced-10 is uniquely required for cell-corpse phagocytosis, and mig-2 and rac-2 have only subtle roles in this process. Rac activators are also used differentially. The UNC-73 Trio Rac GTP exchange factor affected all Rac pathways in axon pathfinding and cell migration but did not affect cell-corpse phagocytosis. CED-5 DOCK180, which acts with CED-10 Rac in cell-corpse phagocytosis, acted with MIG-2 but not CED-10 in axon pathfinding. Thus, distinct regulatory proteins modulate Rac activation and function in different developmental processes.  相似文献   
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Accumulation of lead and zinc was studied in the moss Funariahygrometrica Hedw. collected from mine tailings. Heavy metalaccumulation in gametophytes and sporophytes was quantifiedby graphite furnace atomic absorption spectrometry (GFAAS) andinductively coupled plasma-atomic emission spectrometry (ICP-AES).Pb and Zn accumulation in the placental zone was analysed byx-ray scanning electron microscopy (SEM) and transmission electronmicroscopy (TEM) microanalysis. Spectrometry showed that whilemoss gametophytes accumulated considerable concentrations ofheavy metals, sporophytes accumulated only small concentrationsof metals. X-ray SEM and TEM showed that the two metals accumulatedin placental transfer cells on both the gametophytic and sporophyticsides. To investigate the uptake pattern for both metals undercontrolled conditions, F. hygrometrica plants collected froma non-polluted site were treated in the laboratory with separatesolutions of Pb and Zn at two concentrations (10-2and 10-4 M)for 24 or 168 h. Metal accumulation was analysed separatelyin gametophytes and sporophytes using GFAAS and ICP–AES.Each generation had a different accumulation quotient for bothmetals, and gametophytes accumulated significantly more metalthan sporophytes. Concentrations of Zn in sporophytes were alwayshigher than concentrations of Pb. The findings are discussedin relation to the role performed by the gametophyte and theplacenta in the accumulation and sequestration of Pb and Zn.Copyright 2001 Annals of Botany Company Atomic spectroscopy, Funaria hygrometrica, gametophyte, Pb and Zn accumulation, sporophyte, x-ray TEM and SEM microanalysis  相似文献   
30.
Abstract. The pupal stage of ten Coelometopini species occurring in Australia, New Guinea, Southeast Asia and the Pacific region are described and a key for their identification is provided. The species are Chrysopeplus expolitus Broun, Derosphaerus hirtipes Kaszab, Hypaulax crenata (Boisduval), Leprocaulus borneensis Kaszab, Metisopus purpureipennis Bates, Promethis carteri Kaszab, P. nigra (Blessig), P. quadraticollis (Gebien), P. quadricollis Pascoe and P. sulcigera (Boisduval). The gin trap structures of D. hirtipes and P. quadraticollis are described in detail using scanning electron micrographs. A summary of antipredator structures of all known Coelometopini pupae is given. The phylogenetic value of pupal characters is assessed at intra‐ and intergeneric levels within the tribe.  相似文献   
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