Phylogenetic analysis of Myanmar indigenous chickens using mitochondrial D-loop sequence reveals their characteristics as a genetic resource.

Myanmar indigenous chickens play important roles in food, entertainment, and farm business for the people of Myanmar. In this study, complete mitochondrial D-loop sequences (1232 bp) were analyzed using 176 chickens, including three indigenous breeds, two fighting cock populations, and three indigenous populations to elucidate genetic diversity and accomplish a phylogenetic analysis of Myanmar indigenous chickens. The average haplotype and nucleotide diversities were 0.948 ± 0.009 and 0.00814 ± 0.00024, respectively, exhibiting high genetic diversity of Myanmar indigenous chickens. Sixty-four haplotypes were classified as seven haplogroups, with the majority being haplogroup F. The breeds and populations except Inbinwa had multiple maternal haplogroups, suggesting that they experienced no recent purifying selection and bottleneck events. All breeds and populations examined shared haplogroup F. When 232 sequences belonging to haplogroup F (79 from Myanmar and 153 deposited sequences from other Asian countries/region) were analyzed together, the highest genetic diversity was observed in Myanmar indigenous chickens. Furthermore, Myanmar indigenous chickens and red junglefowls were observed in the center of the star-like median-joining network of 37 F-haplotypes, suggesting that Myanmar is one of the origins of haplogroup F. These findings revealed the unique genetic characteristic of Myanmar indigenous chickens as important genetic resources.

A heterochromatin inducing protein differentially recognizes self versus foreign genomes.

Krüppel-associated box-domain zinc finger protein (KRAB-ZFP) transcriptional repressors recruit TRIM28/KAP1 to heterochromatinize the mammalian genome while also guarding the host by silencing invading foreign genomes. However, how a KRAB-ZFP recognizes target sequences in the natural context of its own or foreign genomes is unclear. Our studies on B-lymphocytes permanently harboring the cancer-causing Epstein-Barr virus (EBV) have shown that SZF1, a KRAB-ZFP, binds to several lytic/replicative phase genes to silence them, thereby promoting the latent/quiescent phase of the virus. As a result, unless SZF1 and its binding partners are displaced from target regions on the viral genome, EBV remains dormant, i.e. refractory to lytic phase-inducing triggers. As SZF1 also heterochromatinizes the cellular genome, we performed in situ footprint mapping on both viral and host genomes in physically separated B-lymphocytes bearing latent or replicative/active EBV genomes. By analyzing footprints, we learned that SZF1 recognizes the host genome through a repeat sequence-bearing motif near centromeres. Remarkably, SZF1 does not use this motif to recognize the EBV genome. Instead, it uses distinct binding sites that lack obvious similarities to each other or the above motif, to silence the viral genome. Virus mutagenesis studies show that these distinct binding sites are not only key to maintaining the established latent phase but also silencing the lytic phase in newly-infected cells, thus enabling the virus to establish latency and transform cells. Notably, these binding sites on the viral genome, when also present on the human genome, are not used by SZF1 to silence host genes during latency. This differential approach towards target site recognition may reflect a strategy by which the host silences and regulates genomes of persistent invaders without jeopardizing its own homeostasis.

Kappa-carrageenan oligosaccharides retard the progression of protein and lipid oxidation in mackerel (Scomber japonicus) fillets during frozen storage.

The antioxidative effects of κ-carrageenan oligosaccharides (CO) on the stability of proteins and lipids in mackerel fillets were determined during frozen storage. Electronic nose analysis indicated that CO treatments maintained the stability of the overall volatile flavor profiles in frozen mackerel. Protein oxidation analysis suggested that the incorporation of CO significantly retarded the rapid decrease of Ca2+-ATPase activity and active sulphydryl (A-SH) contents while also effectively inhibiting the increases in carbonyl content and surface hydrophobicity of myofibrillar proteins (MPs) compared to the control treatments. Lipid stability results showed that the peroxide values (PVs), conjugated diene (CD) content, anisidine values (AVs), and thiobarbituric acid index (TBA-i) values of the extracted lipids were also clearly reduced by CO treatments during frozen storage. Fatty acid composition determinations further confirmed that the permeated CO molecules stabilized the polyunsaturated C22:6n3 (DHA) in the lipids, most likely due to their efficient free radical scavenging activities.

Genetic diversities and population structures of four popular Myanmar local cattle breeds.

Local cattle breeds are popular in Myanmar because they make excellent draught animals, so it is of fundamental importance that their genetic diversities and population structures are elucidated for breeding and conservation purposes. In this study, we characterized the genetic diversities and population structures of four popular Myanmar local cattle breeds and five native cattle populations from neighboring countries (Bangladesh, Laos, Cambodia, and Vietnam) using the GGP Bovine 50K array. The mean observed and expected heterozygosity estimates using pruned datasets ranged from 0.317 and 0.322, respectively, in Cambodia to 0.448 and 0.421, respectively, in Vietnam South. The four Myanmar local breeds exhibited similar levels of genetic diversity. However, AMOVA revealed significant genetic differentiation among the nine populations (p < 0.00001), and Neighbor-Net analysis showed that Shan Ngwar Pu was distinct from the other Myanmar local breeds. Furthermore, PCA and population structure analyses revealed that the native cattle from neighboring countries genetically influenced the Myanmar local breeds to some extent and that the genetic origins could also be observed in the local breeds. These findings highlight the importance of Myanmar local breeds as genetic resources and provide useful information for the future development of breeding strategies and conservation management plans.

Effect of Irbesartan on Chemerin in the Renal Tissues of Diabetic Rats.

BACKGROUND/AIMS: Chemerin was introduced as a novel adipokine that plays a crucial role in insulin signaling and diabetic nephropathy. Serum chemerin levels are significantly elevated in type 2 diabetes patients with macroalbuminuria. However, the underlying mechanisms remain unclear. We conducted a preliminary investigation of the effects of the renin-angiotensin system (RAS) on chemerin expression in streptozotocin-induced diabetic rats. METHODS: Streptozotocin-induced diabetic rats were randomized into control, diabetic, and irbesartan-treated groups. Real-time polymerase chain reaction was used to detect mRNA expression of chemerin, angiotensin II type 1a receptor (AT1a), angiotensin II type 1b receptor (AT1b) and angiotensin II type 2 receptor (AT2). Immunohistochemical staining was used to detect chemerin in renal tissues. RESULTS: Expression levels of chemerin in renal tissues were significantly elevated in the diabetic group compared to the control group. In the irbesartan-treated group, chemerin expression levels and RAS-related protein levels (i.e. AT1a and AT1b) were markedly decreased compared to the diabetic group. Irbesartan treatment reduced chemerin overexpression and RAS-related protein levels in diabetic rats (i.e. AT1a and AT1b). CONCLUSION: Irbesartan may inhibit intrarenal RAS in diabetic rats, which may affect the expression of chemerin in the kidneys; however, the precise underlying mechanism remains to be determined.

Pubertal exposure to thiodiazole copper inhibits thyroid function in juvenile female rats.

Thiodiazole copper, as a thiadiazole fungicide, is widely used in China. The structure of thiodiazole copper shows a close relationship with N,N-methylene-bis (2-amino-1,3,4-thiadiazole) (Bis-A-TDA), which is a teratogen. A few studies have shown that some of the thiadiazole fungicides act as endocrine disruptors via disturbance in thyroid hormone homeostasis. Little is known about the effect of pubertal exposure to thiodiazole copper on the thyroid in pubertal female rats. Based on the protocol of the 20-day Pubertal Female Assay, we attempt to estimate the possible effects of exposure to thiodiazole copper on thyroid hormone and hepatic enzyme activity in female rats. Postnatal days (PND) 22-old Sprague-Dawley rats were administered with thiodiazole copper daily by oral gavage at doses 0, 4, 10, 20 or 30mg/kg/day for 20 days. After treatments, the rats were sacrificed for blood collection; the reproductive organs, liver, pituitary, adrenal and thyroid gland were harvested. The results indicated that changes in thyroid endpoints following thiodiazole copper administration decreased serum triiodothyronine (T(3)) and thyroxine (T(4)) concentrations, increased thyroid stimulating hormone (TSH) concentrations and the weight of thyroid gland, induced hepatic uridine diphosphate glucuronyl transferase (UDPGT) activities in the highest dose group and produced thyroid gland hyperplasia. No histological changes were observed in uterus and ovaries moreover, age and weight at vaginal opening (VO) were unaffected by thiodiazole copper in all treatment groups. The absolute weights of liver and kidney were found to have decreased significantly in female rats. These data and changes demonstrate that thiodiazole copper is likely a thyroid disrupter in female rat following exposure during development, but doesnot have effect on the development of pubertal female rats. Further studies using environmentally relevant doses are needed for hazard identification.

Biodegradation of phenanthrene and pyrene in compost-amended soil.

This study investigated the biodegradation of the polycyclic aromatic hydrocarbons (PAHs) phenanthrene and pyrene in compost and compost-amended soil. The degradation rates of the two PAHs were phenanthrene>pyrene. The degradation of PAH was enhanced when the two PAHs were present simultaneously in the soil. The addition of either of the two types of compost (straw and animal manure) individually enhanced PAH degradation. Compost samples were separated into fractions with various particle size ranges, which spanned 2-50 microm, 50-105 microm, 105-500 microm, and 500-2000 microm. We observed that the compost fractions with smaller particle sizes demonstrated higher PAH degradation rates. However, when the different compost fractions were added to soil, compost particle size had no significant effect on the rate of PAH degradation. Of the micro-organisms isolated from the soil-compost mixtures, strains S1, S2, and S8, which were identified as Arthrobacter nicotianae, Pseudomonas fluorescens, and Bordetella Petrii, respectively, demonstrated the best degradation ability.

[Detection of DNA-protein crosslinks with modified comet assay].

Modifications of the comet assay were introduced to measure crosslinks and the effect of formaldehyde in liver cells of the tested animals was investigated by the new method to see whether the method is feasible. Since exposure of slides to proteinase K can increase DNA migration of the treated cells, the presence of DNA-protein crosslinks can be indicated by compare of the tail moment before and after the proteinase K added. The results showed that the modified protocol of the alkaline comet assay is a fast, inexpensive and sensitive tool for the detection of potent crosslinkers-induced DNA-protein crosslinks at single cell level. Due to its specific advantages, the modified comet assay seems to be a useful tool as a DNA crosslink potency indicator.