Detection and Identification of Two Phytoplasmas (16SrIII‐B and 16SrXII‐A) From Alfalfa (Medicago sativa) in Serbia

Plants of alfalfa (Medicago sativa) exhibiting general stunting, proliferation and phyllody associated with leaf yellowing and reddening were observed in three localities of Central Serbia. Phytoplasma strains belonging to 16SrIII‐B and 16SrXII‐A groups were detected and identified by RFLP and sequence analysis of 16S rDNA. Stolbur phytoplasma tuf gene RFLP analysis showed the presence of the TufAY‐b‐type phytoplasma subgroup in 80% of symptomatic samples. This is the first report of 16SrIII‐B and 16SrXII‐A phytoplasma groups affecting alfalfa in Serbia.     

Historical herbarium specimens in plant molecular systematics — an example from the fern genus <Emphasis Type="Italic">Lindsaea</Emphasis> (Lindsaeaceae)

We extracted, amplified and sequenced DNA from historical herbarium specimens and silica-dried samples of the fern genus Lindsaea in order to study the sequencing success between the two kinds of samples. High quality sequences were obtained from 57% of the herbarium samples. The specimens age was found to be of little importance for sequencing success when less than 75 years, but the colour of a specimen was found more indicative of sequencing success. Shorter DNA fragments were sequenced successfully twice as often as longer fragments from the herbarium material; in relatively recently collected silica-dried material longer sequences were obtained almost as frequently as short ones. No obvious differences in sequencing success between material originating from different herbaria was observed. We conclude that by using specifically designed DNA extraction protocols and by sequencing short DNA fragments from carefully selected specimens, herbarium material and type specimens can be successfully used in molecular systematics. Typical material or specimens from the type locality (topotypes) should be preferred, when placing a species in a phylogeny.     

Systematics of the Alismataceae—A morphological evaluation

The phylogenetic relationships of aquatic plant families Alismataceae and Limnocharitaceae were investigated by cladistic analysis of morphological and cytological characters. The use of morphological data allowed much wider taxon sampling than in recent molecular studies, and resulted in several new hypotheses. Limnocharitaceae was resolved as a paraphyletic group giving rise to the monophyletic Alismataceae, contradicting with the results from molecular studies. Most of the currently accepted genera were relatively well supported as monophyletic groups, with polyphyletic Caldesia and paraphyletic Limnophyton as notable exceptions. Phylogenetic relationships between different genera remained poorly supported, but it is suggested that the base chromosome number n = 11 is derived from the plesiomorphic n = 7.     

The parotid gland is the main source of human salivary epidermal growth factor

To clarify the production of human epidermal growth factor (EGF) by different salivary glands, we measured its concentration by radioimmunoassay separately in whole saliva, in parotid gland (PG) saliva and in mixed submandibular (SMG) and sublingual gland (SLG) saliva. Also, we studied the presence of EGF in PG and SMG by immunohistochemistry. The mean (geometric) concentrations of EGF in PG saliva (2704 pg/ml, +/- SEM interval 2393-3056 pg/ml, n = 20) was higher (p less than 0.001) than in whole saliva (864 pg/ml, +/- 733-1019 pg/ml, n = 29), which in turn was higher (p less than 0.001) than in mixed SMG + SLG saliva (357 pg/ml, +/- 296-430 pg/ml, n = 16). No sex difference existed in any salivary gland EGF. Immunohistochemistry revealed EGF in the acinar cells of both PG and SMG, but only in PG there were prominent EGF deposits in luminal spaces. Our data suggest that EGF is produced by both PG and SMG, but that more of it is secreted from the PG. This result is new and challenges the general view that human salivary EGF is mainly from SMG. In mouse almost all salivary EGF comes from SMG and its amount is androgen dependent. Thus there are great differences in sources and regulation of salivary EGF between man and mouse.     

An experimental study on the effects of polymorphiasis in common eider ducklings.

Eight common eider (Somateria mollissima) ducklings were experimentally infected from 1 June through 13 June, 1995 with acanthocephalans (Polymorphus minutus) by allowing the birds to feed on Gammarus spp. (Gammarus oceanicus, G. salinus, G. zaddachi, and G. lacustris) containing acanthocephalan cystacanths. Uninfected Gammarus spp. were fed to a control group of seven ducklings. No mortality of ducklings occurred during the experiment. However, the infected ducklings gained weight more slowly than the control birds. After the 2 wk study period, the mean serum concentrations of total protein, albumin, beta-globulin, gamma-globulin, fructosamine and creatine kinase were lower in the infected group than in the controls. The mean (+/-SE) number of acanthocephalans in the intestine of the infected ducklings was 21 (+/-4). The parasites were attached to the mucosa of the posterior small intestine of the infected ducklings with a mixed inflammatory reaction consisting of heterophils and mononuclear lymphocytes surrounding the attachment sites.