Differences in the expression of antimicrobial peptides in vivo have been proposed as underlying factors influencing susceptibility to infection. In this context, the role of avian b-defensins in inhibiting avian influenza infections is a study object in an ongoing collaboration with the Zoonotic Ecology and Epidemiology group at Lnu. In this report, an attempt to synthesize two variants of the peptide Anas Platyrhynchos AvBD-8, using Fmoc-based SPPS, is described. The length of AvBD-8 (43 aa) necessitated peptide synthesis in two segments to subsequently be ligated using native chemical ligation. The first component of a 19 aa segment was thus a Dbz-linker, which would allow to ligate this end with a second segment (24 aa). Halfway through the synthesis of this larger segment the batch was split into two pots, allowing the synthesis of two segments differing by one single amino acid (R for W). The composition of these segments were: Dbz-HDTSCTGGAQKCQVANNPA (Dbz-segment), SVVTRCCPIGQKCWGFARTNPPPC(boc) (W-segment), and  SVVTRCCPIGQKCRGFARTNPPPC(boc) (R-segment). Crude product yields were 284,5 mg; 67,6% (Dbz-segment), 137,6 mg; 52,3% (W-segment), and 166,3 mg; 64,2%. Preliminary mass spectrometric analysis on the crude products did not indicate the presence of the desired segments in major mass peaks. Further product purification is necessary in order to allow definite conclusions, but it appears as if the synthesis has not worked. Possible explanations are either impure or degraded reactant(-s), folding or shielding effects of the growing peptide chain at some point inhibiting synthesis, or experimental errors during one or more of the many steps involved in the synthesis.

Sixteen adult male and 8 adult female post moult mallards were equipped with radio transmitters, in a two year study (1977-6AHY-M and 4AHY-F; 1978-10AHY-M and 4AHY-F). Field-feeding was monitored at a lure crop and on adjacent grain fields. Ninety-two percent of the mallards radio-equipped were recorded at a field-feeding site at least once with 71% recorded field-feeding within one week. There was no significant difference in field-feeding activity between males and females. In the morning during periods of rain, mallards field-fed 0.55h longer, arriving 0.30h later and departing 0.9h later than mallards field-feeding during clear weather. The morning field-feeding period was longer in duration than the evening foeld-feeding period. Light intensity was the dominant climatological variable contributing to the arrival of mallards in the morning during periods of no rain (multiple R2=68.1%) and rain (R2=69.5%). Light appeared to act as an initiating cue for morning feeding activity. A high correlation existed between duration of stay during periods of no rain (r=0.815) and rain (r=0.860) suggesting that mallards remained longer at a field-feeding site in the morning by departing later, not arriving earlier. Light intensity was also the dominant climatological variable contributing to the arrival of mallards in the evening amongst those mallards which field-feed in both the morning and evening (R2=78.1%) and those which field-fed in the evening only (R2=63.3%). In addition, light intensity was the only contributing factor in the evening for all mallards departing a field-feeding site (R2=72.7%). Mallards were never recorded field-feeding longer than 15 minutes after there was non measurable light...

Sixteen adult male and 8 adult female post moult mallards were equipped with radio transmitters, in a two year study (1977-6AHY-M and 4AHY-F; 1978-10AHY-M and 4AHY-F). Field-feeding was monitored at a lure crop and on adjacent grain fields. Ninety-two percent of the mallards radio-equipped were recorded at a field-feeding site at least once with 71% recorded field-feeding within one week. There was no significant difference in field-feeding activity between males and females. In the morning during periods of rain, mallards field-fed 0.55h longer, arriving 0.30h later and departing 0.9h later than mallards field-feeding during clear weather. The morning field-feeding period was longer in duration than the evening foeld-feeding period. Light intensity was the dominant climatological variable contributing to the arrival of mallards in the morning during periods of no rain (multiple R2=68.1%) and rain (R2=69.5%). Light appeared to act as an initiating cue for morning feeding activity. A high correlation existed between duration of stay during periods of no rain (r=0.815) and rain (r=0.860) suggesting that mallards remained longer at a field-feeding site in the morning by departing later, not arriving earlier. Light intensity was also the dominant climatological variable contributing to the arrival of mallards in the evening amongst those mallards which field-feed in both the morning and evening (R2=78.1%) and those which field-fed in the evening only (R2=63.3%). In addition, light intensity was the only contributing factor in the evening for all mallards departing a field-feeding site (R2=72.7%). Mallards were never recorded field-feeding longer than 15 minutes after there was non measurable light...

Pienarūgščių bakterijų paieška ir jų identifikavimas migruojančių didžiųjų ančių (Anas platyrhynchos) žarnyne naudojant dalinių 16S rRNR geno sekų analizę ir kultivavimu paremtus metodus Klaidas VARNA Vilniaus Universiteto Ekologijos Institutas, Hidrobiontų Ekologijos ir Fiziologijos Laboratorija bei Populiacinės Genetikos Laboratorija, Akademijos-2, Vilnius-21, 08412, Lietuva. Šiame tyrime pavasarinių ir rudeninių didžiųjų ančių (Anas platyrhynchos) migrantų iš Nemuno deltos virškinamojo trakto pieno rūgšties bakterijų įvairovė buvo ištirta naudojant molekulinius metodus (polimerazės grandininės reakcijos amplifikacija ir dalinių 16S rRNR geno sekų sekvenavimas) ir kultivavimu paremtus metodus. Migruojančių didžiųjų ančių (Anas platyrhynchos) pieno rūgšties bakterijų paieška buvo atlikta pirmą kartą. Rudeniniai didžiųjų ančių migrantai plonojo žarnyno sienelėse (1.2×107 iki 2.1×107 k.f.v./g) ir jų turinyje (nuo 3.4×107 iki 1.1×108 k.f.v./g) turi didesnį pieno rūgšties bakterijų skaičių nei pavasariniai migrantai (atitinkamai nuo 3.2×106 iki 4.8×106 k.f.v./g ir nuo 1.0×107 iki 2.2×107 k.f.v./g). Tiek rudeninių tiek ir pavasarinių didžiųjų ančių migrantų plonojo žarnyno sienelėse ir jų turinyje dominavo kokinės pieno rūgšties bakterijų formos (atitinkamai 65% ir 83.5% bei 81.4% ir 91.6%), o lazdelių buvo mažiau (atitinkamai 35% ir 16.5% bei 18.6% ir 8.4%). Manoma, kad minėtus skirtumus įtakoja keli veiksniai: ilgai trunkanti migracija, perėjimo periodas, skirtingas maistas ir... [toliau žr. visą tekstą] / Identification of lactic acid bacteria in the migrant mallard ducks Anas platyrhynchos intestinal tract by partial 16S rRNA gene sequence analysis and using culture-based techniques Klaidas VARNA Institute of Ecology of Vilnius University, Laboratory of Hydrobionts Ecology and Physiology, Laboratory of Population Genetics, Akademijos-2, Vilnius-21, 08412, Lithuania. In this study the lactic acid bacteria diversity of the intestinal tract content of the vernal and autumnal migrant mallard ducks (Anas platyrhynchos) from Nemuno delta has been investigated by molecular methods: polymerase chain reaction amplification and sequencing of partial 16S rRNA genes and using culture-based techniques. The investigation of the lactic acid bacteria of the migrant mallard ducks has been performed the first time. Autumnal migrant mallard ducks in the small intestine walls (from 1.2×107 until 2.1×107 c.f.u./g) and in their content (from 3.4×107 until 1.1×108 c.f.u./g have the greatest number of the lactic acid bacteria then vernal migrants (respectively from 3.2×106 until 4.8×106 c.f.u./g and from 1.0×107 until 2.2×107 c.f.u./g). In the small intestine walls and in their content of the autumnal and vernal migrant mallard ducks, dominated cocci-shaped lactic acid bacteria (respectively 65% and 83.5%, 81.4% and 91.6%), whereas rod-shaped was under (respectively 35% and 16.5%, 18.6% and 8.4%). Supposedly, that these defferences determine some factors: a long migration, period of incubate... [to full text]