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The aim of this study was to determine the potential use of Pediococcus acidilactici (31 strains) and Pediococcus pentasaceus (2 strains) strains isolated from sausage as starter culture. For this purpose, lactic acid production, proteolytic activity, lipolytic activity, nitrate reductase activity and antibacterial substance production ability were investigated in Pediococcus strains. When pH measurements at the end of 6th and 24th hours incubation period were compared in three different culture media (skim milk, skim milk with glucose and MRS) the highest pH change (ΔpH) was measured between 1.71 and 2.49 at the end of 24 hours incubation period in MRS broth. The highest lactic acid production was also determined as 0.83-1.62 % in MRS broth at the end of 24 hours incubation period. None of the strains showed proteolytic activity and lipolytic activity in agar media. Twenty two of Pediococcus strains showed strong nitrate reductase activity, while 4 of Pediococcus have weak nitrate reductase activity. In addition, all Pediococcus strains have been found to inhibit indicator bacteria. As a result, it has been determined that Pediococcus strains that produce fast acid, have nitrate reductase and antibacterial activity can be used as starter culture in the production of fermented meat products., Bu çalışmanın amacı, sucuktan izole edilen Pediococcus acidilactici (31 adet) ve Pediococcus pentasaceus (2 adet) suşlarının starter kültür olarak kullanım potansiyellerinin belirlenmesidir. Bu amaçla Pediococcus suşlarında laktik asit üretimi, proteolitik aktivite, lipolitik aktivite, nitrat redüktaz aktivitesi ve antibakteriyel madde üretim yetenekleri araştırılmıştır. Üç farklı besiyerinde (skim milk besiyeri, glukoz içeren skim milk besiyeri ve MRS broth besiyeri) 6. saat ve 24. saat sonunda yapılan pH ölçümleri kıyaslandığında en yüksek ΔpH değeri MRS broth besiyerinde 24 saat sonunda 1.71-2.49 aralığında hesaplanmıştır. En yüksek laktik asit üretimi de yine MRS broth besiyerinde 24 saat sonunda % 0.83-1.62 aralığında bulunmuştur. Suşların hiçbiri besiyeri ortamlarında proteolitik ve lipolitik aktivite göstermemiştir. Yirmi iki Pediococcus suşu kuvvetli, 4’ü ise zayıf nitrat redüktaz aktivitesi göstermiştir. Ayrıca tüm Pediococcus suşlarının indikatör bakterileri inhibe ettiği saptanmıştır. Sonuç olarak, hızlı asit üreten, nitrat redüktaz ve antibakteriyel aktiviteye sahip olduğu belirlenen Pediococcus suşlarının fermente et ürünleri üretiminde starter kültür olarak kullanılabileceği tespit edilmiştir.

Bu çalışmada Uludağ'ın sub-alpin ve alpin kuşağındaki bozulmuş alanlarda egemen olan ruderal bitki Verbascum olympicum Boiss. (Sığır kuyruğu)'a ait fideler laboratuvar koşullarında (gece/gündüz sıcaklığı 15C/25C, 16 saat ışık/8 saat karanlık periyot) Hoagland besin çözeltisinde yetiştirilerek farklı konsantrasyon ve sürelerde kadmiyum (Cd), krom (Cr), bakır (Cu), nikel (Ni) ve çinko (Zn) uygulamasına maruz bırakılmıştır. Örnekleme dönemlerinde hasat edilen, metal uygulanmış ve uygulanmamış (kontrol grubu) fidelerin kök ve yapraklarında biyokütle (mg KA), su içeriği (%), eriyebilir protein içeriği (mg g-1), lipid peroksidasyonu (MDA içeriği, nmol/g YA), hücre membran zararı (%), iyon sızıntısı (%), azot metabolizması (Nitrat redüktaz: NR, Glutamin sentetaz: GS) ve antioksidatif savunma sistemi enzimlerinin (Süperoksitdismutaz: SOD, Askorbat peroksidaz: APX ve Katalaz: CAT) aktivitesi tayin edilmiştir. Ayrıca yaprak kısımlarında klorofil içeriği (klorofil a, b ve total klorofil; mg/g YA) belirlenmiştir. Elde edilen veriler İki-Yönlü (Two-Way ANOVA) varyans testi ile analiz edilmiştir (α:0,05). Araştırılan metallerin çoğunlukla konsantrasyon ve uygulama süresine bağlı olarak biyokütle, su içeriği, eriyebilir protein ve klorofil içeriğinde azalışa, MDA, hücre membran zararı ve iyon sızıntısında artışa neden olduğu tespit edilmiştir. Nitrat redüktaz ve glutamin sentetazın metal uygulamalarından genellikle olumsuz etkilendiği, buna karşın antioksidatif savunma sistemi enzimlerinin (SOD, APX ve CAT) aktivitesinin uygulama süresi ve konsantrasyona bağlı olarak artma eğiliminde olduğu belirlenmiştir. Bu sonuçlar V. olympicum'un ağır metal stresinden bir dereceye kadar etkilenmesine rağmen ağır metaller ile başa çıkmak için güçlü bir antioksidatif savunma sistemine sahip olduğunu ve Uludağ'da bozulmuş alanlarda gelişip sekonder süksesyon sürecindeki rolünü ortaya koymaktadır. In this study, the seedlings of ruderal Verbascum olympicum Boiss. which is dominated in areas of sub-alpine and alpine belts of Uludag Mountain were grown in Hoagland nutrient solution with controlled conditions (day/night temperature 15C/25C, 16 h light/8 h dark) and they were treated with different concentrations and durations of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn). Biomass (mg DW), water content (%), chlorophyll content (chlorophyll a, b and total chlorophyll; mg/g FW), lipid peroxidation (MDA content, nmol/g FW), electrolyte leakage (%) and cell membrane damage (%) with the changes in the enzyme activities of nitrogen metabolism (Nitrate reductase: NR, Glutamine synthetase: GS) and antioxidative defence system (Superoxidedismutase: SOD, Askorbate peroxidase: APX and Catalase: CAT) in root and leaves of the metal treated and control plants. Chlorophyll content was also determined in leaves. The differences among the means of values for examined parameters according to different metal concentrations and exposure periods by a Two-Way ANOVA (α:0,05). It was generally found that biomass, water content, chlorophyll content and protein content was decreased, MDA, electrolyte leakage and cell membrane damage were increased depending on concentration and duration in examined metals. Nitrate reductase and glutamine synthetase activities were negatively affected by metal treatments, whereas it was determined an increase tendency in antioxidative defence system enzyme (SOD, CAT, APX) activities. It can be concluded that although V. olympicum was affected to a certain extent from metal treatments, it has a powerful antioxidative defence system to cope with heavy metal stress and it has an important role in seconder succession on Uludag disturbed areas via this properties. 294

Spathoglottis plicata is highly sought after by florists and orchid growers due to its unique structure and colors. However, this orchid is a slow-growing type and thus the planting materials are acutely limited. Therefore, there is a need to improve its multiplication efficiency and speed up its growth in order to meet the market demand. Benzyladenine purine (BAP) has been widely used to improve plantlet multiplication in plant cultures. Polyamines have also been reported to improve the growth and development of in vitro cultures. The objective of this study was to investigate the effects of BAP and different polyamines on the physical and biochemical changes of protocorm-like bodies (PLBs) of S. plicata. Different concentrations of BAP and polyamines (putrescine, spermine, and spermidine) were used. BAP and polyamines were supplemented singly in half-strength MS medium and PLBs were cultured for 2 weeks. It was observed that 5 µM BAP and 25 µM spermidine resulted in the highest fresh weights of 0.38 g and 0.31 g, respectively. The total soluble protein and carbohydrate content for PLBs treated with 25 µM spermidine was 4.85 mg/g FW and 6.36 mg/g FW. A separate experiment was carried out to investigate the interactive effects of 25 µM spermidine with 5 µM BAP. The presence of spermidine in the media reduced the peroxidase and catalase activities by increasing the nitrate reductase activity.

Leaf rolling is a dehydration avoidance mechanism for plants under drought stress. To understand how it affects the lignification process in response to long-term drought stress in Ctenanthe setosa plants that have the leaf-rolling mechanism, the enzymes in lignification were studied in unrolled leaves as a control and at 2 different leaf rolling indices at days 35 and 47 of the drought period. The results indicated that the activities of phenylalanine ammonia lyase, indole-3-acetic acid oxidase, soluble peroxidase, ionically wall-bound peroxidase, covalently wall-bound peroxidase, and polyphenol oxidase were increased during long-term drought stress. However, nitrate reductase activity was decreased while lignin content was increasing during the period of drought. Lignin content was positively correlated to activities of phenylalanine ammonia lyase, indole-3-acetic acid oxidase, soluble peroxidase, ionically wall-bound peroxidase, and polyphenol oxidase, but it was negatively correlated to activity of nitrate reductase. Furthermore, there was a positive correlation between leaf rolling and lignin content. The results indicate that the leaf-rolling process may be related to the lignification mechanism in alleviating damage from stress in Ctenanthe setosa under long-term drought stress.