The potential role of intestinal intraepithelial lymphocytes (i-IELs) in the generation of host protective immunity after helminth infection was investigated using the Trichinella spiralis (Owen, 1835)/mouse model. In this study we found a significant rise of TCRyô i-IELs (P < 0.001) concurrent with the jejunal goblet cells (GC) hyperplasia in T. spiralis-infected C57BL mice on day 4 p.i. However, no direct relationship between the kinetics of the increase in TCRy5+ i-IELs and T, spiralis expulsion was observed in infected mice. Taken together, these results implicate that γδ i-IELs probably perform a unique functions related to the regulation of the CiC proliferation accompanying T. spiralis gut infection. As is known, these TCRyS* i-IELs may release mediators or growth factors that in turn influence GC differentiation. With the use of dexamethason (DEX), a potent anti-inflammatory agent which also induces apoplotic ceil death in i-IELs, wc have confirmed that the expulsion of T. spiralis from the mouse gut is accompanied by an inflammatory response. Indeed, the GC are clearly involved in these phenomena, apparently under the regulation by TCRy8+ i-lEL-mediated responses, since DEX abrogated GC proliferation in T. spiralis-infected C57BL mice and subsequently augmented adult worm burden. Our data also show that the rejection of adult worms starts concurrently with a significant increase in TCRaß* and CDS* i-IELs (P < 0.05 and P < 0.01, respectively), namely by day 7 p.i. At the same time, CD4* cells significantly decreased (P < 0.05) in the intestinal epithelium of T. spira/ir-infected, ví uninfected mice. These results may indicate that the TCRaß4 and CDS* i-IELs act as effectors of anti-7’, spiralis defence reactions. The implications of these findings for the potential role of intestinal intraepithélial CD8 and TCRaß' cells in the pathogenesis of the intestinal lesions during T. spiralis gut infection are discussed.
Absorption, fluorescence and delayed luminescence (in ps time range) of cyanobacterium Tolypothrix tenuis (Kutz) adapted to green (GR) and red (RR) radiation and dissolved in 15% polyvinyl alcohol Solutions were measured. Fluorescence and delayed luminescence depended on the adaptation to radiation and the wavelength of fluorescence excitation. This suggests that paths of deactivation of excitation in pigment-protein complexes present in organisms adapted to GR and RR differ.
A new nematode genus and species, Lucionema balatonense gen. et sp. п., is described from the swimbladder of the European pikeperch, Stizostedion lucioperca (L.), from Lake Balaton in Hungary; a new dracunculoid family Lucionematidae fam. n. is established to accommodate it. The hitherto monotypie family Lucionematidae shows affinities with the families Skrja-billanidae and Daniconematidae, differing from them mainly in having simple oesophagus without external oesophageal glands and the vulva situated near the middle of body; from the first family also in the absence of the buccal capsule and the bursa-like caudal alae in the male. The genus Lucionema gen. n. is characterized mainly by the presence of 8 cephalic papillae in two circlets, absence of spicules, presence of the copulatory plate, only 2 pairs of postanal papillae in the male, and by the distal part of the monodelphic uterus forming a posteriorly directed coil. The body length of L. balatonense females is 1074-1782 pm, that of the only available male 770 pm. A key to the families of the Dracunculoidea is presented.
Photosynthetic pathway types (C3 and C4 species) and their dynamics along grazing gradient were determined for 42 plant species in 30 genera and 13 families from the Songnen grassland, Northeastern China. Of the total, 10 species in 9 genera and 4 families had C4 photosynthesis; 32 species in 21 genera and 12 families had C3 photosynthesis. The proportion of C4 species in total plants and C4/C3 increased with grazing intensity, and peaked in overgrazed plot. Most of the increased C4 species (6 of 10) along the grazed gradient were annual grasses and halophytes. This indicated that the C4 species had greater capacity to tolerate environmental stresses (e.g. drought and saline) caused by animal grazing in the Songnen grassland, Northeastern China.
Photosystem 2 (PS 2) reaction centers inactive in plastoquinone pool reduction are present in isolated thylakoid membranes, intact chloroplasts, and leaves of dark- adapted plants. Here we describe om recent work investigating the physical and physiological properties that distínguish inactive firom active centers. Inactive PS 2 centers are defíned by their slow rate of Q^’ oxidation. They háve a competent water oxidation systém and constitute about one-third of the total PS 2 present in dark- adapted leaves and thylakoid membranes. Their effective absorption cross section for radiant energy utilization is half that of active PS 2 centers. Irradiation modifies inactive PS 2 centers in leaves and thylakoid membranes. The modification is manifested by a 50 % dechne of their varíable fluorescence and of their contribution to the electrochromic shift. In leaves the light-induced modification is reversible in the dark, whereas it is irreversible in thylakoid membranes.