Correlation between soil characters and forest types: a study in multiple discriminant analysis

Multiple discriminant analysis is a useful multivariate technique in vegetation studies that can be employed for several purposes, even if the underlying statistical assumptions are not satisfied. An example of application of this method is discussed: multiple discriminant analysis was successfully used for evaluating the predictivity of forest types defined by numerical classification of vegetation data with respect to soil variables.Species nomenclature follows Pignatti (1982) for vascular plants and Augier (1966) for mosses.The research has been supported by the IDROSER (Bologna, Italy) and by the Italian C. N. R. (Grant no. 83.02548.04, resp. Prof. A. Pirola). We wish to thank Prof. E. Feoli, Prof. E. van der Maarel, Prof. L. Orlóci and Prof. A. Pirola for suggestions. We are also indebted to Dr N. Filippi who analyzed the soil samples.     

Mire vegetation in the Apuanian Alps (Italy)

Mire vegetation in the Apuanian Alps (N Italy) is analyzed from the phytosociological and the synecological points of view. Three vegetation types are delimited by numerical methods and compared with mire communities of the Alps and the Apennines. Furthermore, a chorological evaluation of this vegetation is attempted on a floristical basis.     

Blood amino acids in chronic HBsAg positive liver disease

Typical changes in blood aminoacid concentrations have been described in patients with severe liver disease. In this study we measured the serum amino acid levels, by Beckman Aminoacid Analyzer, in 11 healthy subjects and 24 HBsAg-positive patients with biopsy-proven liver disease (4 CPH, 10 CAH, 10 cirrhosis). A significant decrease in total aminoacids was observed in CAH and cirrhosis groups (-24% and -22% respectively). The three branched chain aminoacids (BCAA = val + leu + isoleu) were reduced by 24% (P less than 0.002) and 37% (P less than 0.001) in the CAH and cirrhosis groups respectively. Tyrosine was the only of the aromatic aminoacids (AAA) to increase in cirrhotics (+ 34%, P less than 0.02). The molar ratio BCAA/AAA was 3.6 in controls, 3.8 in CPH, 3.1 in CAH (P less than 0.025) and 1.9 in cirrhosis (P less than 0.001). A linear correlation was found between molar ratio BCAA/AAA and serum albumin in all patients (P less than 0.001). These results document the presence of specific quantitative changes in serum aminoacids of HBsAg positive patients, which appear related to severity of liver disease and comparable to the alterations described in non viral chronic liver disease.     

An ultrastructural study of oogenesis in a marine triclad

The ultrastructural features of oocyte differentiation were studied in the marine triclad Cercyra hastata. Oocytes at several stages of maturation, each surrounded by follicle cell projections, are present within each of the two ovaries. A pre-vitellogenic and a vitellogenic stage have been detected in the oogenesis of C. hastata. The pre-vitellogenic stage is mainly characterized by an increase in the nuclear and nucleolar volume and activity, and the appearance and development of cortical granule precursors which are elaborated by the Golgi complex. In early phases of the vitellogenic stage, intense delamination and blebbing of the nuclear envelope occurs which probably contributes to an increase in number of cytoplasmic membranes and to transfer of nuclear material to the cytoplasm. The rough endoplasmic reticulum is extensively developed and often assumes a ‘whorl’ array. Several areas of yolk precursor formation appear in the whorls. Numerous 2–5 μm protein yolk globules are subsequently formed which appear surrounded by a double membrane (cisternae of the smooth endoplasmic reticulum) and become randomly distributed throughout the cytoplasm of mature oocytes. The peripheral ooplasm is occupied by a monolayer of electron-dense cortical granules. Finally, the evolutionary significance of the autosynthetic mechanism of yolk production is discussed.