Placoid and polyodontode scales of stem chondrichthyans have been found in the early Lochkovian “Ditton

Group” of the Brown Clee Hill district, Shropshire, England and at Talgarth, south Wales. One of the forms is

assigned to a new species of Altholepis Karatajūtė-Talimaa, 1997, a genus already recognised from Lochkovian

shallow marine deposits in Celtiberia, Spain and the Northwest Territories, Canada as well as the type locality in

Podolia, Ukraine. Altholepis salopensis sp. nov. is based on small polyodontode scales with typically three to eight

high odontodes; the scale form was previously considered to belong to acanthodian “Nostolepis” robusta (Brotzen,

1934). The structure of other scales formerly assigned to “Nostolepis” robusta has led us to erect a new genus

Jolepis for this scale form, which differs from Altholepis in lacking an ordered layout of odontodes. Jolepis robusta

(Brotzen, 1934), originally (and possibly still) considered to be an acanthodian, is also known from the Baltic

countries, Russia, and northern Germany (ex erratic limestones). Scales of acanthodian Parexus recurvus Agassiz,

1845, and/or possibly from the stem chondrichthyan Seretolepis elegans Karatajūtė-Talimaa, 1968 (scales of these

two taxa are barely distinguishable), and of stem chondrichthyan Polymerolepis whitei Karatajūtė-Talimaa, 1968

are also present. Altholepis, Jolepis gen. nov., Seretolepis Karatajūtė-Talimaa, 1968 and Polymerolepis Karatajūtė-

Talimaa, 1968 are found in marine deposits elsewhere; the British occurrence of these taxa adds to the debate on

the sedimentological origins of the Lower Old Red Sandstone deposits in the Welsh Borderland. The geographic

range of several early sharks is now known to extend around the Old Red Sandstone continent and beyond.

Artemisinin is a powerful antimalarial drug, useful in the treatment of many diseases, includ- ing chickens coccidiosis. Its toxic effects have been well studied in humans and experimental animals, but not sufficiently in broiler chickens. Therefore, in the present study, we aimed to assess the side effects of artemisinin in chickens, by measuring the serum level of proteins and enzymes (ALT, AST, GGT, ALP, CK), by histopathological examination and by the evaluation of relative weight of organs (liver, kidney, heart). Artemisinin was administered in the standard feed for chickens in three different concentrations: 5, 50 and 500 ppm.

Each concentration of artemisinin increased the total serum proteins, gamma-globulins and the serum activity of CK and decreased the serum ALP level. The values of ALT and GGT were higher in the chickens treated with 50 and 500 ppm of artemisinin. Multifocal liver necrosis and inflammatory infiltrate were detected in the chickens that received the 50 and 500 ppm dosage of artemisinin. Minimal tubular necrosis, renal tubular epithelium vacuolation, multifocal interstitial nephritis and mild uric nephrosis were detected in chickens treated with the drug. Artemisinin administration produced no significant changes in the organs relative weight.

Artemisinin, at a concentration of 5 mg/kg of feed is well tolerated by broiler chickens, but the concentrations of 50 and 500 mg/ kg feed can produce toxic effects.

Resistance genes in response to root-knot nematode (Meloidogyne javanica) infection suppress one or more of several critical steps in nematode parasitism and their reproduction rate. The reaction of seven commercial tomato genotypes to M. javanica infection was investigated under greenhouse conditions. Current results classified these genotypes as: three resistant (Jampakt, Malika and Nema Guard), one moderately resistant (Fayrouz), and three susceptible (Castle Rock, Super Marmande and Super Strain B). Except Nema Guard, nematode infection significantly reduced plant height, fresh and dry weights of shoots of the other tomato genotypes. Leaf area was significantly reduced for all examined tomato genotypes except Malika and Nema Guard. Total chlorophyll was reduced in all tested tomato genotypes except Jampakt. Infection parameters of M. javanica and their population were significantly reduced on all nematode-resistant tomato genotypes compared to the susceptible genotypes. Also, the maturation rate of M. javanica was suppressed in the resistant genotypes compared to the susceptible genotypes. These results were confirmed by histological study that illustrated a delay in nematode development and their maturation. Total phenolic content significantly increased in nematode infected roots of both resistant and susceptible genotypes except Malika. Among non-infected roots, Malika showed the highest level of total phenols while after M. javanica infection, Nema Guard revealed the highest level of total phenols. Among infected roots, the highest level of total phenols was recorded in Castle Rock. These results suggested that using nematode-resistant tomato genotypes could provide an efficient and nonpolluting method to control root-knot nematodes.

The new rich collection of fossil fish remains obtained during the Polish Spitsbergen Expedition of 1998 includes many isolated shark teeth, mostly of the genera Lissodus, Hybodus and Acrodus. The shark microfossils from the Hornsund area (South Spitsbergen) described here and the analysis of the histology of Lissodus teeth contribute to a better understanding of the previously described Early Triassic fish fauna from that region (Birkenmajer and Jerzmańska 1979). There is the evidence for coexistence of two types of histology within a single taxon what closes the discussion considering ortho- and osteodentine as a taxonomic factor.

Analysis of weathering parameters of bones from cave deposits is presented as a useful tool of palaeoenvironmental reconstruction. As an example, we studied profiles of sediments in two Palaeolithic sites: Nietoperzowa Cave and Deszczowa Cave. Our studies included histological and EDS analyses of bone remnants found in these profiles. This method allowed us to reconstruct the changes of palaeotemperature and palaeohumidity, and finally the climatostratigraphy of sediments. The results presented here put a new light onto the stratigraphy of Deszczowa Cave's filling. In particular, besides the Vistulian sediments (MIS 2-5d), we confirmed the presence oflayers formed during the Penultimate Glaciation (MIS 6) and Eemian Interglacial (MIS 5e).