On the excited-state energy transfer between tryptophan residues in proteins: the case of penicillin acylase

The problem, whether excited-state energy transfer occurs between Trp residues in a multi-tryptophan proteins and if it does, what kind of changes it induces in different parameters of protein fluorescence, is currently under active investigation. In our previous paper [Biophys. Chem. 72 (1998) 265], the energy transfer was found and studied in detail for Na,K-ATPase. It was shown that this transfer influences all parameters of fluorescence emission, which is detected at site-selective conditions (red-edge of excitation, blue and red edges of emission). Present experiments were performed on unusually tryptophan-rich protein, bacterial penicillin acylase (28 Trp per dimer of 82 kDa) and were aimed to extend these observations. They demonstrate substantial heterogeneity in the environments of tryptophan residues within the protein structure. This suggests, that in the present case, if the energy transfer exists, it should be directed from short-wavelength-emitting to long-wavelength-emitting tryptophan residues and thus could be easily observed by a number of time-resolved and steady-state fluorescence techniques. Unexpectedly, no signature of inter-tryptophan energy transfer was found.     

Natural history of 11 cases of twin-twin transfusion syndrome without intervention.

The natural history of 11 cases of twin-twin transfusion syndrome (TTTS) in monochorionic diamniotic (MCDA) twin pregnancies has been reviewed. Seven cases before 28 weeks and four pregnancies after 28 weeks had been followed up without intervention. Eight cases had premature uterine contractions. All seven pregnancies before 28 weeks aborted, leading to a 100% mortality rate. After 28 weeks all mothers delivered live births. The diagnosis of TTTS before 28 weeks, and with premature uterine contraction, seems to be a poor prognostic sign.     

The effect of genistein supplementation on performance and antioxidant status of Japanese Quail under heat stress

Genistein, a phytoestrogen found in soybeans, is a powerful antioxidant. We evaluated the effects of genistein supplementation on performance, carcass characteristics, levels of malondialdehyde (MDA), homocysteine, vitamins C, E, A in Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature of 34°C. Two hundred and forty Japanese quails (10 d old) were randomly assigned to eight treatment groups consisting of 10 replicates of three birds. The birds were kept in an environmental controlled room either for 24 h/d at 22°C with (thermoneutral, TN groups) or for 16 h/d at 22°C and for 8 h/d (09.00 am to 05.00 pm) at 34°C (heat stress, HS groups). Birds were fed either a basal (control) diet (TN and HS) or the basal diet supplemented with 200, 400 or 800 mg of genistein per kg of diet. Heat exposure decreased birds' performance when basal diet was fed. Increase in feed intake and body weight, and improvement of feed efficiency and carcass traits were found in genistein-supplemented quails reared under heat stress conditions. Growth rate and feed efficiency improved in quails reared under thermo-neutral conditions as well. Concentration of serum vitamins C, E, and A increased in supplemented birds reared at high temperature, while non-significant changes occurred in TN groups. With genistein supplementation homocysteine levels in serum and MDA levels in serum and liver decreased in all birds of both TN and HS groups. Effects of genistein were relatively greater in heat-stressed quails than in quails kept under thermo-neutral conditions. Results of the present study suggest that supplementation with genistein can be considered to be protective by reducing the negative effects of oxidative stress induced by heat stress in quail.     

The influence of copper on alkaline protease stability toward autolysis and thermal inactivation

Alkaline proteases are one of the most important group of enzymes that are indispensable in a number of different industrial sectors. In this work, the effect of copper ions (Cu²⁺) was investigated for improving the thermostability and hydrolytic performance of Bacillus clausii GMBE 42 alkaline protease at different temperatures (45–65°C). Maximal residual activity was observed in the presence of 5 mM CuCl₂. The enzyme was thermoinactivated according to first‐order kinetics. A stabilization effect caused by copper ions was the result of a decrease in both autolysis and thermoinactivation rates. Thermodynamic analysis of the thermoinactivation process showed that E_a,i, ΔG_i, and ΔH_i values of the enzyme were higher in the presence of copper ions, but there was no measurable change in ΔS_i values. These results show the thermostabilizing potential of copper ions on the enzyme. Lower K_m values and higher k_cat and k_cat/K_m values were obtained in the presence of copper ions, which is an indication of the nonessential activation of the enzyme by copper ions. Thermodynamic analysis of casein hydrolysis showed that in presence of copper ions E_a, ΔG^≠, ΔH^≠, , and values of enzyme were lower, but there was no change in ΔS^≠ values. This is so far the first study that investigates the effect of cations on the basic catalytic and thermodynamic properties of an alkaline serine protease, which may be used to remove protein wastes from various industries such as food and leather processing.     

Investigation of mucus obtained from different fish species on the acute pain induced with scalpel incision in paw of rats

No comparative study could be found for the analgesic activity of mucuses from the Oncorhynchus mykiss (OM), Salvelinus fontinalis (SF), Salmo coruhensis (SC), Acipenser gueldenstaedtii (AG), and Acipenser baerii (AB) fish species in the literature. We aimed to investigate the effects of mucuses obtained from the abovementioned fish species on scalpel incision-induced pain in the rat paw and to examine the role of oxidant/antioxidant parameters and COX-2 gene expression in the analgesic activities. Animals were divided into groups: SIC (scalpel incision; SI), SIDS (SI+25 mg/kg diclofenac sodium), SOM (SI+25 mg/kg OM mucus), SFM (SI+25 mg/kg SF mucus), SCM (SI+25 mg/kg SC mucus), SAgM (SI+25 mg/kg AG mucus), SAbM (SI+25 mg/kg AB mucus), and HG (healthy). The paw pain thresholds were measured with a Basile algesimeter before and after diclofenac sodium (DS) or mucus administration, and then the rats were euthanized with thiopental sodium. Oxidant/antioxidant and COX-2 gene expression parameters were measured in paw tissues. OM, SC, AG, and AB fish mucuses could not decrease the SI-induced pain. However, SF fish mucus prevented this pain by 69% after the first hour and by 58.3% after the third hour. DS was shown to suppress pain more weakly than SF, preventing the pain by 62.1% and 50.0% after the first and third hours, respectively. SF mucus and DS significantly inhibited increase of COX-2 gene expression, while other fish mucuses could not. None of the fish mucuses except SF mucus in conjunction with DS could significantly inhibit the increase in oxidant parameters and decrease in antioxidants. SF fish mucus should be comparatively assessed in clinical practice for treatment of postoperative pain.     

Lutz's spontaneous sedimentation technique and the paleoparasitological analysis of sambaqui (shell mound) sediments

Parasite findings in sambaquis (shell mounds) are scarce. Although the 121 shell mound samples were previously analysed in our laboratory, we only recently obtained the first positive results. In the sambaqui of Guapi, Rio de Janeiro, Brazil, paleoparasitological analysis was performed on sediment samples collected from various archaeological layers, including the superficial layer as a control. Eggs of Acanthocephala, Ascaridoidea and Heterakoidea were found in the archaeological layers. We applied various techniques and concluded that Lutz''s spontaneous sedimentation technique is effective for concentrating parasite eggs in sambaqui soil for microscopic analysis.     

Morphological and anatomical studies on economically important Empetrum nigrum L. subsp.hermaphroditum (hagerup) bocher (empetraceae)

The study is based on anatomical and morphological investigations of Empetrum nigrum L. subsp. Hermaphroditum (Hagerup) Bocher, an important plant because of its value for medicine and food. Plant samples were collected from the northeastern part of Turkey. Morphological and anatomical features of various plant parts (e.g., stem, leaf, flower, and fruit) are illustrated and described in detail.