Aldrin Epoxidation in Flathead Mullet (Mugil cephalus): Possible Involvement of CYP1A and CYP3A

The primary objective of this study was to determine specific cytochrome P450 isozyme(s) involved in the metabolism of aldrin to its toxic metabolite dieldrin in flathead mullet (Mugil cephalus) liver microsomes. To identify the cytochrome P450 isozyme responsible for the aldrin metabolism in mullet liver, the effects of mammalian‐specific cytochrome P450 inhibitors and substrates were determined in the epoxidation reaction of aldrin. CYP3A‐related inhibitors, ketoconazole, SKF‐525A, and cimetidine, inhibited the metabolism of aldrin. The contribution of CYP1A to the aldrin metabolism was shown by the inhibition of 7‐ethoxyresorufin‐O‐deethylase activity in the presence of aldrin. The results indicate that CY1A and CYP3A are the cytochrome P450s involved in aldrin epoxidase activity in mullet. In addition, the suitability of aldrin epoxidase activity for monitoring of environmental pollution was also assessed in the fish samples caught from four different locations of the West Black Sea coast of Turkey.     

Consistent picture of the reversible thermal unfolding of hen egg-white lysozyme from experiment and molecular dynamics

Synchrotron radiation circular dichroism, Fourier transform infrared, and nuclear magnetic resonance spectroscopies, and small-angle x-ray scattering were used to monitor the reversible thermal unfolding of hen egg white lysozyme. The results were compared with crystal structures and high- and low-temperature structures derived from molecular-dynamics calculations. The results of both experimental and computational methods indicate that the unfolding process starts with the loss of β-structures followed by the reversible loss of helix content from ∼40% at 20°C to 27% at 70°C and ∼20% at 77°C, beyond which unfolding becomes irreversible. Concomitantly there is a reversible increase in the radius of gyration of the protein from 15 Å to 18 Å. The reversible decrease in forward x-ray scattering demonstrates a lack of aggregation upon unfolding, suggesting the change is due to a larger dilation of hydration water than of bulk water. Molecular-dynamics simulations suggest a similar sequence of events and are in good agreement with the ¹H^N chemical shift differences in nuclear magnetic resonance. This study demonstrates the power of complementary methods for elucidating unfolding/refolding processes and the nature of both the unfolded structure, for which there is no crystallographic data, and the partially unfolded forms of the protein that can lead to fibril formation and disease.     

Ecological Genetic Divergence of the Fungal Pathogen Didymella rabiei on Sympatric Wild and Domesticated Cicer spp. (Chickpea)

For millennia, chickpea (Cicer arietinum) has been grown in the Levant sympatrically with wild Cicer species. Chickpea is traditionally spring-sown, while its wild relatives germinate in the autumn and develop in the winter. It has been hypothesized that the human-directed shift of domesticated chickpea to summer production was an attempt to escape the devastating Ascochyta disease caused by Didymella rabiei. We estimated genetic divergence between D. rabiei isolates sampled from wild Cicer judaicum and domesticated C. arietinum and the potential role of temperature adaptation in this divergence. Neutral genetic markers showed strong differentiation between pathogen samples from the two hosts. Isolates from domesticated chickpea demonstrated increased adaptation to higher temperatures when grown in vitro compared with isolates from the wild host. The distribution of temperature responses among progeny from crosses of isolates from C. judaicum with isolates from C. arietinum was continuous, suggesting polygenic control of this trait. In vivo inoculations of host plants indicated that pathogenic fitness of the native isolates was higher than that of their hybrid progeny. The results indicate that there is a potential for adaptation to higher temperatures; however, the chances for formation of hybrids which are capable of parasitizing both hosts over a broad temperature range are low. We hypothesize that this pathogenic fitness cost is due to breakdown of coadapted gene complexes controlling pathogenic fitness on each host and may be responsible for maintenance of genetic differentiation between the pathogen demes.Environmental heterogeneity and genetic variability in host populations are major factors distinguishing natural from agricultural habitats. These differences exert powerful selective forces on plants and their pathogens, shaping the biology of pathosystems, epidemiological patterns, and pathogenic fitness (11, 21). Plant pathogens are dependent upon the abiotic environment as well as on their host plants and are subjected to strong selective forces exerted by their hosts. This process is shaped especially (but not exclusively) by genetic variation at loci controlling differential host specificity, which may ultimately be an important driver in speciation (37, 48, 49).The Neolithic revolution and the adoption of farming have had a large impact on plant communities as well as their related pathogens (11, 34, 57). The long-term interplay between plant pathogens and their hosts and the resulting evolutionary trajectories may have different patterns in natural plant communities as compared to agro-ecosystems (12). One striking observation is that pathogens of natural plant populations, although prevalent, rarely cause the destruction of their hosts (21). Therefore, investigations of the epidemiological and biological differences between pathogen populations from wild and domesticated origins are of fundamental interest and are highly relevant to understanding disease patterns, parasite evolution, and host resistance in agricultural systems. Such studies are expected to be especially fruitful in the centers of origin of crop species, because these regions are generally considered to be pathogen centers of origin as well (40, 57).Throughout West Asia, wild cereals and legumes and their domesticated derivatives have been growing sympatrically since the beginning of Near Eastern farming systems (41, 61). Domesticated chickpea, Cicer arietinum L, is grown sympatrically with a number of annual and perennial Cicer relatives, including the immediate wild progenitor of domesticated chickpea, C. reticulatum Ladiz (39, 58). Following the Neolithic agricultural revolution in southeastern Turkey (41), the Near Eastern crop package spread in all directions throughout the east Mediterranean and reached the southern Levant within 1 millennium (2, 3). This “passage” of the cultigens, from their core region in southeast Turkey into the southern Levant, traversed populations of many of their wild progenitors and more distantly related wild relatives (e.g., wild barley, wild emmer wheat, wild bitter vetch, wild lentils, and wild peas), (2, 3). Presumably, these natural populations were infested by pathogens capable of infecting the domesticated forms (2, 20, 24).Domesticated chickpea differs from the Near Eastern founder crops in its seasonal growth pattern. While most founder crops have retained the autumnal germination/spring maturation cycle like their wild relatives, domesticated chickpea is a spring-sown crop, germinating and developing up to 4 months later than its wild relatives (1, 3). This shift of life cycle is puzzling since water availability in the Levant is a major yield-limiting factor and autumn-sown crops enjoy a substantial yield benefit. It has been recently hypothesized that this shift was driven by the extreme vulnerability of chickpea to Ascochyta blight during the rainy season and was the only means to secure stable yields in ancient times (3). Didymella rabiei (Kovachevski) var. Arx. (Anamorph: Ascochyta rabiei (Pass) Labr.) is one of the most destructive diseases of domesticated chickpea, affecting all above-ground parts of the plant. Secondary spread of D. rabiei conidia occurs through rain splash, and epidemic intensity is governed by rain frequency and quantity. As Ascochyta blight epidemics proceed, foci of diseased plants become visible. Unlike other Ascochyta diseases of legumes and Septoria diseases of cereals, Ascochyta blight of chickpea may cause total yield loss under the appropriate environmental conditions (43). Autumn-sown chickpea is severely affected by Ascochyta blight because the crop growth period coincides with the rainy season and optimum environmental conditions for pathogen development and spread (3, 56).Unlike the often massive stands of wild cereals, C. reticulatum has a very narrow and fragmented distribution (2, 8, 38). However, other wild annual Cicer taxa are more common across the region and can be found in close proximity to the domesticated crop (1, 8). In the southern Levant, domesticated chickpea is grown sympatrically, often just few meters apart from C. judaicum (27). C. judaicum grows in patchy distributions in stony/rocky habitats in Israel and neighboring territories, mostly in sites with annual precipitation of >480 mm and altitude of <900 m (6). Unlike C. judaicum, modern chickpea cropping in Israel spans large tracts of land employing a 5-year rotation in individual fields. Recently, D. rabiei isolates sampled from C. judaicum and isolates sampled from C. arietinum were studied and found to be better adapted to their respective original host than to the other Cicer species (26, 27). In addition, in vitro hyphal growth rate experiments exposed an adaptation to higher temperatures among isolates originating from C. arietinum compared to isolates from C. judaicum (26). Given that the natural growing season of C. judaicum occurs during the Levantine winter and that chickpea is a traditional spring-sown crop in the region, it is likely that the apparent adaptation to higher temperatures of D. rabiei isolates from domesticated chickpea may represent an ecological shift following the introduction of summer cropping practices in the Near East (3). These sympatric wild and domesticated pathosystems of Cicer/Ascochyta represent a unique opportunity for studying the genetic basis of the pathogen''s ecological adaptation and its association with pathogenic fitness. Such a system may also help to determine the role of ecological factors and pathogenic fitness in pathogenic divergence and the evolutionary relationships among pathogen populations in natural and human-directed agro-ecosystems (57).In this context, our underlying hypotheses were as follows: (i) isolates sampled from C. arietinum and C. judaicum are conspecific but represent genetically distinct populations; (ii) the temperature growth response of D. rabiei isolates from C. judaicum and C. arietinum has a heritable genetic basis; (iii) the temperature growth response plays an important role in the ongoing pathogen divergence process and, therefore, it is expected to have high heritability values; and (iv) the existence of two sympatric D. rabiei populations (demes) requires the action of one or more genetic isolation mechanisms. In accord with the above hypotheses, the aims of this study were (i) to assess the genetic differentiation between D. rabiei isolates originating from C. judaicum versus C. arietinum, (ii) to determine the genetic basis of temperature response and estimate its heritability, and (iii) to assess the relationship between temperature adaptation and pathogenic fitness among progeny from crosses between D. rabiei isolates from C. judaicum and C. arietinum on the two original hosts.     

The histopathologic evaluation of soft tissue changes in rabbit extremity after different dose-fractionation schemes of interstitial high dose rate (HDR) brachytherapy

Background

The use of HDR in the treatment of soft tissue sarcoma had been on the rise. However, there was limited study to evaluate the effect of different fractionation schemes on soft tissue and the optimal HDR scheme.

Aims

We aimed to assess the histopathologic changes on soft tissue after different HDR brachytherapy doses.

Methods

The subjects were divided into three groups. Each group included 10 limbs. Group A had only an applicator without radiation, group B received a total of 24 Gy at 6 Gy per fraction, twice a day, and group C received a total of 13.5 Gy in a single fraction. The histopathologic findings were grouped into soft tissue pathology-1 (edema, inflammation, endothelial proliferation, necrosis) and soft tissue pathology-2 (atrophy, calcification, vascular hyalinization, fibrosis) (STP-1–2).

Results

The highest mean grade values of STP-1 and STP-2 were observed in group C (0.95 and 1.45) in comparison to group A (0.45 and 0.85) and group B (0.65 and 0.9). The difference in STP-1 was found significant only between groups A and C and the difference in STP-2 was found both between groups A and C and groups B and C.

Conclusion

In our experimental study it was shown that the fractionated interstitial HDR had both lower rate and severity of toxicity in comparison to a single high dose fraction. Before using a single fractionated regimen in the clinic, the increased morbidity related to the irreversible early toxicities or progressive late toxicities should be kept in mind.     

Inhibition of substance P activity prevents stress-induced bladder damage

Substance P is a neuropeptide involved in inflammation, immune regulation and stress response. Stress may induce bladder damage by stimulating inflammatory response such as mast cell activation. We here examined the role substance P during stress-induced mast cell degranulation and urothelial injury in rat bladder. Adult Sprague-Dawley rats (200-270 g) were either exposed to cold-immobilization stress or substance P (SP) intracerebroventricularly. Different doses of substance P receptor (NK1R) antagonist CP 99994 were administered peripherally or centrally before the stress exposure. From each group, samples of the bladder were examined with light and electron microscope. Stress- and SP-injected centrally, increased the number of both granulated and degranulated mast cells. Ultrastructurally, urothelial degeneration with vacuolization in the cytoplasm and dilated intercellular spaces were seen. Both central and peripheral injection of CP 99994 prevented stress-induced urothelial degeneration as well as stress-induced mast cell degranulation. In conclusion, centrally and peripherally released substance P is involved in stress-induced bladder damage. Inhibition of NK1R prevents stress-induced pathological changes of urinary bladder and NK1R antagonist can be considered for the treatment of inflammatory bladder diseases.     

Determination of Genetic Diversity of Vitis vinifera cv. Kabarcik Populations from the Coruh Valley Using SSR Markers

Northeastern Turkey is recognized as one of the most important germplasm centers for the grape in the world. In the present study, simple sequence repeat markers were used to investigate the genetic diversity between four Vitis vinifera cv. Kabarcik populations sampled from the Coruh Valley in Turkey, at altitudes of 800-1,150 m. The mean observed number of alleles per locus varied from 2 (loci VVMD7 and VVMD24) to 6 (VVS2) among populations. The population from the highest altitude showed the greatest average number of alleles, 4.5. With regard to the six loci examined in all populations, the mean observed heterozygosity was higher than the expected heterozygosity. Among the loci, VVS2 (probability of identity = 0.137) was found to be the most informative among populations. Genetic distances between populations ranged from 0.072 to 0.216. Genetic differentiation among populations was strongly related to geographic distances in all populations.     

Contraction–relaxation coupling is unaltered by exercise training and infarction in isolated canine myocardium

The two main phases of the mammalian cardiac cycle are contraction and relaxation; however, whether there is a connection between them in humans is not well understood. Routine exercise has been shown to improve cardiac function, morphology, and molecular signatures. Likewise, the acute and chronic changes that occur in the heart in response to injury, disease, and stress are well characterized, albeit not fully understood. In this study, we investigated how exercise and myocardial injury affect contraction–relaxation coupling. We retrospectively analyzed the correlation between the maximal speed of contraction and the maximal speed of relaxation of canine myocardium after receiving surgically induced myocardial infarction, followed by either sedentary recovery or exercise training for 10–12 wk. We used isolated right ventricular trabeculae, which were electrically paced at different lengths, frequencies, and with increasing β-adrenoceptor stimulation. In all conditions, contraction and relaxation were linearly correlated, irrespective of injury or training history. Based on these results and the available literature, we posit that contraction–relaxation coupling is a fundamental myocardial property that resides in the structural arrangement of proteins at the level of the sarcomere and that this may be regulated by the actions of cardiac myosin binding protein C (cMyBP-C) on actin and myosin.     

Morphological,anatomical and cytological investigation on endemic <Emphasis Type="Italic">Lamium moschatum</Emphasis> var. <Emphasis Type="Italic">rhodium</Emphasis>

In this study, the morphological and anatomical features of endemic Lamium moschatum Miller var. rhodium (Gand.) R. Mill (Lamiaceae) are described in detail. Lamium moschatum var. rhodium has an annual taproot. The stem is erect and clearly quadrangular. The leaves are broadly ovate to cordate-ovate or nearly suborbicular in shape. Inflorescense is verticillate cyme. The corolla is white and the tube is curved and bears an annulus inside, near the base. Cross-sections of the root, stem, petiole, leaf, calyx, corolla and generative organs were examined and the anatomical features of the taxon are discussed. Furthermore, glandular hairs distributed on the plant taxon are shown. In karyological research, chromosome numbers were determined as 2n = 18. The results are presented with photographs and tables.     

Evaluation of Genetic Diversity in Lemons and Some of Their Relatives Based on SRAP and SSR Markers

Genetic diversity was evaluated by sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) markers among 45 lemons (Citrus limon (L.) Burm. f.), five citrons (Citrus medica L.), four rough lemons (Citrus jambhiri Lush), and two Citrus volkameriana accessions. Twenty-one SRAP primer combinations produced a total of 141 (77%) polymorphic fragments with an average of 6.7 fragments per primer combinations whereas 13 SSR primers produced a total of 26 (76%) polymorphic fragments with an average of 2.0 per primer. The unweighted pair-group method arithmetic average analysis as assessed with combined SRAP and SSR data demonstrated that the accessions had a similarity range from 0.65 to 1.00. Rough lemons and C. volkameriana accessions were relatively closely related. In lemon group, accessions from hybrid origin were distant from the others. We also applied principal components analysis (PCA) for a better presentation of relation among the accessions studies. Using PCA, 88.7% of the total variation in the original dimensions could be represented by just the two dimensions defined by the first two PCs. Although nearly all accessions could be distinguished, there was a low level of genetic diversity detected among lemon cultivars.