Astrocytic crosstalk with brain and immune cells in healthy and diseased conditions.

Astrocytes interact with various cell types, including neurons, vascular cells, microglia, and peripheral immune cells. These interactions are crucial for regulating normal brain functions as well as modulating neuroinflammation in pathological conditions. Recent transcriptomic and proteomic studies have identified critical molecules involved in astrocytic crosstalk with other cells, shedding light on their roles in maintaining brain homeostasis in both healthy and diseased conditions. Astrocytes perform these various roles through either direct or indirect physical associations with neuronal synapses and vasculature. Furthermore, astrocytes can communicate with other immune cells, such as microglia, T cells, and natural killer cells, through secreted molecules during neuroinflammation. In this review, we discuss the critical molecular basis of this astrocytic crosstalk and the underlying mechanisms of astrocyte communication with other cells. We propose that astrocytes function as a central hub in inter-connecting neurons, vasculatures, and immune cells in healthy and diseased brains.

Influence of Zika virus 3'-end sequence and nonstructural protein evolution on the viral replication competence and virulence.

Zika virus (ZIKV) has been circulating in human networks over 70 years since its first appearance in Africa, yet little is known about whether the viral 3'-terminal sequence and nonstructural (NS) protein diverged genetically from ancient ZIKV have different effects on viral replication and virulence in currently prevailing Asian lineage ZIKV. Here we show, by a reverse genetics approach using an infectious cDNA clone for a consensus sequence (Con1) of ZIKV, which represents Asian ZIKV strains, and another clone derived from the MR766 strain isolated in Uganda, Africa in 1947, that the 3'-end sequence -UUUCU-3' homogeneously present in MR766 genome and the -GUCU-3' sequence strictly conserved in Asian ZIKV isolates are functionally equivalent in viral replication and gene expression. By gene swapping experiments using the two infectious cDNA clones, we show that the NS1-5 proteins of MR766 enhance replication competence of ZIKV Con1. The Con1, which was less virulent than MR766, acquired severe bilateral hindlimb paralysis when its NS1-5 genes were replaced by the counterparts of MR766 in type I interferon receptor (IFNAR1)-deficient A129 mice. Moreover, MR766 NS5 RNA-dependent RNA polymerase (RdRp) alone also rendered the Con1 virulent, despite there being no difference in RdRp activity between MR766 and Con1 NS5 proteins. By contrast, the Con1 derivatives expressing MR766 Nsps, like Con1, did not develop severe disease in wild-type mice treated with an IFNAR1 blocking antibody. Together, our findings uncover an unprecedented role for ZIKV NS proteins in determining viral pathogenicity in immunocompromised hosts.

Anti-inflammatory clearance of amyloid-ß by a chimeric Gas6 fusion protein.

Clearing amyloid-ß (Aß) through immunotherapy is one of the most promising therapeutic approaches to Alzheimer's disease (AD). Although several monoclonal antibodies against Aß have been shown to substantially reduce Aß burden in patients with AD, their effects on improving cognitive function remain marginal. In addition, a significant portion of patients treated with Aß-targeting antibodies experience brain edema and microhemorrhage associated with antibody-mediated Fc receptor activation in the brain. Here, we develop a phagocytosis inducer for Aß consisting of a single-chain variable fragment of an Aß-targeting monoclonal antibody fused with a truncated receptor binding domain of growth arrest-specific 6 (Gas6), a bridging molecule for the clearance of dead cells via TAM (TYRO3, AXL, and MERTK) receptors. This chimeric fusion protein (αAß-Gas6) selectively eliminates Aß plaques through TAM receptor-dependent phagocytosis without inducing NF-kB-mediated inflammatory responses or reactive gliosis. Furthermore, αAß-Gas6 can induce synergistic clearance of Aß by activating both microglial and astrocytic phagocytosis, resulting in better behavioral outcomes with substantially reduced synapse elimination and microhemorrhage in AD and cerebral amyloid angiopathy model mice compared with Aß antibody treatment. Our results suggest that αAß-Gas6 could be a novel immunotherapeutic agent for AD that overcomes the side effects of conventional antibody therapy.

Antibody-mediated delivery of a viral MHC-I epitope into the cytosol of target tumor cells repurposes virus-specific CD8+ T cells for cancer immunotherapy.

BACKGROUND: Redirecting pre-existing virus-specific cytotoxic CD8+ T lymphocytes (CTLs) to tumors by simulating a viral infection of the tumor cells has great potential for cancer immunotherapy. However, this strategy is limited by lack of amenable method for viral antigen delivery into the cytosol of target tumors. Here, we addressed the limit by developing a CD8+ T cell epitope-delivering antibody, termed a TEDbody, which was engineered to deliver a viral MHC-I epitope peptide into the cytosol of target tumor cells by fusion with a tumor-specific cytosol-penetrating antibody. METHODS: To direct human cytomegalovirus (CMV)-specific CTLs against tumors, we designed a series of TEDbodies carrying various CMV pp65 antigen-derived peptides. CMV-specific CTLs from blood of CMV-seropositive healthy donors were expanded for use in in vitro and in vivo experiments. Comprehensive cellular assays were performed to determine the presentation mechanism of TEDbody-mediated CMV peptide-MHC-I complex (CMV-pMHCI) on the surface of target tumor cells and the recognition and lysis by CMV-specific CTLs. In vivo CMV-pMHCI presentation and antitumor efficacy of TEDbody were evaluated in immunodeficient mice bearing human tumors. RESULTS: TEDbody delivered the fused epitope peptides into target tumor cells to be intracellularly processed and surface displayed in the form of CMV-pMHCI, leading to disguise target tumor cells as virally infected cells for recognition and lysis by CMV-specific CTLs. When systemically injected into tumor-bearing immunodeficient mice, TEDbody efficiently marked tumor cells with CMV-pMHCI to augment the proliferation and cytotoxic property of tumor-infiltrated CMV-specific CTLs, resulting in significant inhibition of the in vivo tumor growth by redirecting adoptively transferred CMV-specific CTLs. Further, combination of TEDbody with anti-OX40 agonistic antibody substantially enhanced the in vivo antitumor activity. CONCLUSION: Our study offers an effective technology for MHC-I antigen cytosolic delivery. TEDbody may thus have utility as a therapeutic cancer vaccine to redirect pre-existing anti-viral CTLs arising from previously exposed viral infections to attack tumors.

A distinct astrocyte subtype in the aging mouse brain characterized by impaired protein homeostasis.

The aging brain exhibits a region-specific reduction in synapse number and plasticity. Although astrocytes play central roles in regulating synapses, it is unclear how changes in astrocytes contribute to age-dependent cognitive decline and vulnerability to neurodegenerative diseases. Here, we identified a unique astrocyte subtype that exhibits dysregulated autophagy and morphology in aging hippocampus. In these autophagy-dysregulated astrocytes (APDAs), autophagosomes abnormally accumulate in swollen processes, impairing protein trafficking and secretion. We found that reduced mammalian target of rapamycin (mTOR) and proteasome activities with lysosomal dysfunction generate APDAs in an age-dependent manner. Secretion of synaptogenic molecules and astrocytic synapse elimination were significantly impaired in APDAs, suggesting that APDAs have lost their ability to control synapse number and homeostasis. Indeed, excitatory synapses and dendritic spines associated with APDAs were significantly reduced. Finally, we found that mouse brains with Alzheimer's disease showed a significantly accelerated increase in APDAs, suggesting potential roles for APDAs in age- and Alzheimer's disease-related cognitive decline and synaptic pathology.

Single random measurement of urinary gonadotropin concentration for screening and monitoring girls with central precocious puberty.

PURPOSE: The gold standard for assessing pubertal activation is the gonadotropinreleasing hormone (GnRH) stimulation test (GnRHST), which is invasive, timeconsuming, and inconvenient. This study evaluated whether a single random measurement of urinary luteinizing hormone (LH) concentration could substitute for the GnRHST in diagnosing and monitoring central precocious puberty (CPP) in girls. METHODS: Fifty-five girls with breast buds before 8 years of age were assessed by both the GnRHST and urinary gonadotropin assays. Based on the GnRHST results, 29 girls were assigned to the CPP group (peak LH≥5 IU/L), and 26 were placed in the premature thelarche (PT) group (peak LH<5 IU/L). Auxological data and urine and serum samples were collected at baseline and after treatment with a GnRH agonist for 12 and 24 weeks. RESULTS: Although the auxological data did not differ between the 2 groups, the serum levels of insulin-like growth factor-1, basal LH, follicle-stimulating hormone (FSH), estradiol, and peak LH; urinary LH; and peak serum LH/FSH and urinary LH/FSH ratios were higher in the CPP group than in the PT group. Pearson correlation analysis showed a positive correlation between the urinary and serum LH concentrations (r=0.660, P<0.001). Receiver-operating characteristic curve analyses showed that a urinary LH concentration of 0.725 IU/L was a cutoff that significantly predicted positivity on the GnRHST. Urinary LH and FSH concentrations declined significantly during GnRH agonist treatment. CONCLUSION: A single, random measurement of urinary gonadotropin concentration could be a reliable tool for initial screening and therapeutic monitoring of CPP in girls.

A mutation in Zeaxanthin epoxidase contributes to orange coloration and alters carotenoid contents in pepper fruit (Capsicum annuum).

Phytoene synthase (PSY1), capsanthin-capsorubin synthase (CCS), and pseudo-response regulator 2 (PRR2) are three major genes controlling fruit color in pepper (Capsicum spp.). However, the diversity of fruit color in pepper cannot be completely explained by these three genes. Here, we used an F2 population derived from Capsicum annuum 'SNU-mini Orange' (SO) and C. annuum 'SNU-mini Yellow' (SY), both harboring functional PSY1 and mutated CCS, and observed that yellow color was dominant over orange color. We performed genotyping-by-sequencing and mapped the genetic locus to a 6.8-Mb region on chromosome 2, which we named CaOr. We discovered a splicing mutation in the zeaxanthin epoxidase (ZEP) gene within this region leading to a premature stop codon. HPLC analysis showed that SO contained higher amounts of zeaxanthin and total carotenoids in mature fruits than SY. A color complementation assay using Escherichia coli harboring carotenoid biosynthetic genes showed that the mutant ZEP protein had reduced enzymatic activity. Transmission electron microscopy of plastids revealed that the ZEP mutation affected plastid development with more rod-shaped inner membrane structures in chromoplasts of mature SO fruits. To validate the role of ZEP in fruit color formation, we performed virus-induced gene silencing of ZEP in the yellow-fruit cultivar C. annuum 'Micropep Yellow' (MY). The silencing of ZEP caused significant changes in the ratios of zeaxanthin to its downstream products and increased total carotenoid contents. Thus, we conclude that the ZEP genotype can determine orange or yellow mature fruit color in pepper.

Affinity Maturation of a T-Cell Receptor-Like Antibody Specific for a Cytomegalovirus pp65-Derived Peptide Presented by HLA-A*02:01.

Human cytomegalovirus (CMV) infection is widespread among adults (60-90%) and is usually undetected in healthy individuals without symptoms but can cause severe diseases in immunocompromised hosts. T-cell receptor (TCR)-like antibodies (Abs), which recognize complex antigens (peptide-MHC complex, pMHC) composed of MHC molecules with embedded short peptides derived from intracellular proteins, including pathogenic viral proteins, can serve as diagnostic and/or therapeutic agents. In this study, we aimed to engineer a TCR-like Ab specific for pMHC comprising a CMV pp65 protein-derived peptide (495NLVPMVATV503; hereafter, CMVpp65495-503) in complex with MHC-I molecule human leukocyte antigen (HLA)-A*02:01 (CMVpp65495-503/HLA-A*02:01) to increase affinity by sequential mutagenesis of complementarity-determining regions using yeast surface display technology. Compared with the parental Ab, the final generated Ab (C1-17) showed ~67-fold enhanced binding affinity (KD ≈ 5.2 nM) for the soluble pMHC, thereby detecting the cell surface-displayed CMVpp65495-503/HLA-A*02:01 complex with high sensitivity and exquisite specificity. Thus, the new high-affinity TCR-like Ab may be used for the detection and treatment of CMV infection.

The roles of astrocytic phagocytosis in maintaining homeostasis of brains.

In the central nervous system, microglia are regarded as the main cells responsible for phagocytosis, contributing to neural circuit refinement and homeostasis through synapse elimination. However, recent findings have shown that astrocytes also actively participate in synapse homeostasis through phagocytosing synapses, neuronal debris, axonal mitochondria, and pathological protein aggregates. In addition, it has been also suggested that astrocytes may regulate microglial phagocytosis by secreting molecules such as IL-33 and C3. Here, we have introduced key findings regarding direct and indirect astrocyte-mediated phagocytosis in CNS development, the sleep/wake cycle, and aging. We have also discussed current information about reactive astrocytes and their phagocytic function in the diseased brain, focusing on ischemia and Alzheimer's disease. Through this review, we aim to provide an overview of the current status as well as future perspectives regarding the important role of astrocytic control of phagocytosis.

Identification of an Allelic Variant of the CsOr Gene Controlling Fruit Endocarp Color in Cucumber (Cucumis sativus L.) Using Genotyping-By-Sequencing (GBS) and Whole-Genome Sequencing.

The cucumber is a major vegetable crop around the world. Fruit flesh color is an important quality trait in cucumber and flesh color mainly depends on the relative content of ß-carotene in the fruits. The ß-carotene serves as a precursor of vitamin A, which has dietary benefits for human health. Cucumbers with orange flesh contain a higher amount of ß-carotene than white fruit flesh. Therefore, development of orange-fleshed cucumber varieties is gaining attention for improved nutritional benefits. In this study, we performed genotyping-by-sequencing (GBS) based on genetic mapping and whole-genome sequencing to identify the orange endocarp color gene in the cucumber breeding line, CS-B. Genetic mapping, genetic sequencing, and genetic segregation analyses showed that a single recessive gene (CsaV3_6G040750) encodes a chaperone DnaJ protein (DnaJ) protein at the Cucumis sativus(CsOr) locus was responsible for the orange endocarp phenotype in the CS-B line. The Or gene harbored point mutations T13G and T17C in the first exon of the coding region, resulting in serine to alanine at position 13 and isoleucine to threonine at position 17, respectively. CS-B line displayed increased ß-carotene content in the endocarp tissue, corresponding to elevated expression of CsOr gene at fruit developmental stages. Identifying novel missense mutations in the CsOr gene could provide new insights into the role of Or mechanism of action for orange fruit flesh in cucumber and serve as a valuable resource for developing ß-carotene-rich cucumbers varieties with increased nutritional benefits.

Astrocytes phagocytose adult hippocampal synapses for circuit homeostasis.

In the adult hippocampus, synapses are constantly formed and eliminated1,2. However, the exact function of synapse elimination in the adult brain, and how it is regulated, are largely unknown. Here we show that astrocytic phagocytosis3 is important for maintaining proper hippocampal synaptic connectivity and plasticity. By using fluorescent phagocytosis reporters, we find that excitatory and inhibitory synapses are eliminated by glial phagocytosis in the CA1 region of the adult mouse hippocampus. Unexpectedly, we found that astrocytes have a major role in the neuronal activity-dependent elimination of excitatory synapses. Furthermore, mice in which astrocytes lack the phagocytic receptor MEGF10 show a reduction in the elimination of excitatory synapses; as a result, excessive but functionally impaired synapses accumulate. Finally, Megf10-knockout mice show defective long-term synaptic plasticity and impaired formation of hippocampal memories. Together, our data provide strong evidence that astrocytes eliminate unnecessary excitatory synaptic connections in the adult hippocampus through MEGF10, and that this astrocytic function is crucial for maintaining circuit connectivity and thereby supporting cognitive function.

Hydrolyzed Yeast Supplementation in Calf Starter Promotes Innate Immune Responses in Holstein Calves under Weaning Stress Condition.

Weaned calves are susceptible to infectious diseases because of the stress and malnutrition that occurs during weaning. Therefore, the dairy industry requires effective feed additives to ameliorate stress responses and promote immunity. This study aimed to investigate the effects of hydrolyzed yeast (HY) supplementation on the growth performance, immune and stress parameters, and health status of calves after weaning. Eighteen Holstein calves were randomly assigned to two groups, either receiving a control calf starter or 0.2% HY calf starter from one week of age. All calves were weaned at six weeks of age as a stress challenge. The HY-fed calves had a significantly-higher body weight gain during the post-weaning period (kg/week) compared to the control. Cortisol levels at three days post-weaning (DPW) were significantly lower in the HY group than the control group. Calves fed HY had significantly-higher serum levels of tumor necrosis factor-α and interleukin-1ß at one DPW. The HY-fed calves also had higher concentrations of the acute-phase proteins, haptoglobin, serum amyloid A, and transferrin at one DPW. In addition, the diarrhea severity in HY-fed calves was milder after weaning compared to the control group. Our results indicate that HY supplementation reduces stress responses and may promote innate immunity in newly-weaned calves.

Negative effect of methyl bromide fumigation work on the central nervous system.

Methyl bromide (MB) is a fumigant that has been widely used for killing pests on plants in trade, soils, and structures worldwide due to its excellent permeability and insecticidal effect; however, MB should be replaced because it is an ozone-depleting substance. It is well-known that MB is highly toxic and hazardous to workers, but the effects of exposure in asymptomatic workers have not been explored. The purpose of this study is to investigate the impact of MB fumigation on the health of fumigators at a sensitive level. The electroencephalogram (EEG) and urinary bromide ion levels of 44 fumigators (the study group) and 20 inspectors (the control) were measured before and after fumigation work from February to August 2019 in Busan, Korea. The mean post-work concentration of bromide ion (18.311 µg/mg CRE) in the fumigators was significantly increased from the pre-work level (7.390 µg/mg CRE) (P<0.001). The fumigator post-work median frequencies (MDF) and alpha-to-theta ratios (ATR) of EEG index were significantly decreased compared to the pre-work values (P<0.05 for all indices). In contrast, there were no significant differences in inspector EEG indices and urinary bromide ion. The urinary bromide ion levels in all the subjects were negatively correlated with MDF (P = 0.032). In conclusion, fumigators' EEG indices and urinary bromide ion suggested that occupational exposure to MB negatively affected the health of workers, although the workers were asymptomatic.

Use of the shock index to predict maternal outcomes in women referred for postpartum hemorrhage.

OBJECTIVE: To evaluate the clinical significance of various vital signs in women referred for postpartum hemorrhage (PPH). METHODS: This retrospective study included patients with primary PPH who were referred to Korea University Medical Center, Ansan, between January 1, 2004, and December 31, 2016. We analyzed data for systolic and diastolic blood pressure, heart rate, and shock index (heart rate divided by systolic blood pressure) at time of arrival. Significant morbidity, such as massive transfusion, invasive procedures, and admission to the intensive care unit were reviewed. We used the area under the receiver operating characteristic curve (AUROC) for each vital sign to predict adverse maternal  outcomes. Sensitivity, specificity, and negative and positive predictive values were assessed. RESULTS: 118 women with PPH were identified. The shock index had the highest AUROC to predict massive transfusion (0.815, 95% confidence interval [CI] 0.727-0.883). A shock index greater than 0.9 had 93.8% (95% CI 69.8-99.8) sensitivity and 51.2% (35.1-67.1) specificity for prediction of massive transfusion, and 93.6% (78.6-99.2) sensitivity and 31.0% (15.3-50.8) specificity for prediction of invasive procedures. CONCLUSION: The shock index has significant ability to predict adverse outcomes of PPH compared with other initial vital signs when patients are referred.

Clinical Implications of Serial Glucose Measurements in Acute Ischemic Stroke Patients Treated with Intravenous Thrombolysis.

Serial glucose might more accurately reflect glycemic status in acute ischemic stroke (AIS) than presenting glucose. We sought to investigate the clinical implications of various parameters of serial glucose on the outcomes of patients with AIS treated with intravenous thrombolysis (IVT). This was a single-center, prospective, observational study of stroke patients treated with IVT. Blood glucose (BG) was serially measured at 6-time points during the first 24 h of IVT. The primary endpoint analyzed was a good outcome at 3 m. Among the 492 patients in the cohort (age, 70 ± 12 y; men, 57%), the overall BG level was 131 ± 33 mg/dl. At 3 m, 40.4% of the patients had a good outcome. Patients with good outcomes had significantly lower mean BG (121 vs 128 mg/dl) and higher coefficient of variance (CoV, 17% vs 14%) but no differences in the others. For patients with higher mBG (every 30 mg/dl), the likelihood of achieving a good outcome decreased (OR 0.82, 95% CI 0.67-1.02). For patients with higher CoV (every 10%), the likelihood of a good outcome increased (OR 1.38, 95% CI 1.12-1.71). The results showed that higher mBG and lower CoV were consistently associated with worse outcomes in IV-thrombolyzed stroke patients, suggesting that lowering BG might be potential therapeutic target.

Pattern of pharmacotherapy by episode types for patients with bipolar disorders and its concordance with treatment guidelines.

This study aimed to investigate the overall prescription pattern for patients with bipolar disorders in Korea and its relevance to the practice guidelines. Prescription records from all patients with bipolar I and II disorders who have been admitted or who started the outpatient treatment during the year of 2009 in 10 academic setting hospitals were reviewed. A total of 1447 patients with bipolar I and II disorders were included in this study. Longitudinal prescription patterns of inpatients and outpatients were analyzed by episode types and compared with the clinical practice guideline algorithms. In all phases, polypharmacy was chosen as an initial treatment strategy (>80%). The combination of mood stabilizer and atypical antipsychotics was the most favored. Antipsychotics were prescribed in more than 80% of subjects across all phases. The rate of antidepressant use ranged from 15% to 40%, and it was more frequently used in acute treatment and bipolar II subjects. The concordance rate of prescriptions for manic inpatients to the guidelines was higher and relatively more consistent (43.8%-48.7%) compared with that for depressive inpatients (18.6%-46.9%). Polypharmacy was the most common reason for nonconcordance. In Korean psychiatric academic setting, polypharmacy and atypical antipsychotics were prominently favored in the treatment of bipolar disorder, even with the lack of evidence of its superiority. More evidence is needed to establish suitable treatment strategies. In particular, the treatment strategy for acute bipolar depression awaits more consensuses.

Meta-analysis of factors affecting milk component yields in dairy cattle.

The objectives of this study were thus to identify most significant factors that determine milk component yield (MCY) using a meta-analysis and, if possible, to develop equations to predict MCY using variables that can be easily measured in the field. A literature database was constructed based on the research articles published in the Journal of Dairy Science from Oct., 2007 till May, 2010. The database consisted of a total of 442 observed means for MCY from 118 studies. The candidate factors that determine MCY were those which can be routinely measured in the field (e.g. DMI, BW, dietary forage content, chemical composition of diets). Using a simple linear regression, the best equations for predicting milk fat yield(MFY) and milk protein yield (MPY) were MFY = 0.351 (±0.068) + 0.038 (±0.003) DMI (R(2) = 0.27), and MPY = 0.552 (±0.071) + 0.031 (±0.002) DMI - 0.004 (±0.001) FpDM (%, forage as a percentage of dietary DM) (R(2) = 0.38), respectively. The best equation for predicting milk fat content (%) explained only 12% of variations in milk fat content, and none of a single variable can explain more than 5% of variations in milk protein content. We concluded that among the tested variables, DMI was the only significant factor that affects MFY and both DMI and FpDM significantly affect MPY. However, predictability of linear equations was relatively low. Further studies are needed to identify other variables that can predict milk component yield more accurately.

Anti-inflammatory Effect of Oyster Shell Extract in LPS-stimulated Raw 264.7 Cells.

This study was designed to investigate the anti-inflammatory effect of oyster shell extract on the production of pro-inflammatory factors [NO, reactive oxygen species (ROS), nuclear factor-kappa B (NF-κB), inducible nitric oxide synthase (iNOS) and cycloxygenase-2 (COX-2)] and pro-inflammatory cytokines [Interleukin-1ß (IL-1ß), Interleukin-6 (IL-6) and TNF-α] in the lipopolysaccharide (LPS)-stimulated Raw 264.7 cells. Cell viability, as measured by the MTT assay, showed that oyster shell extract had no significant cytotoxicity in Raw 264.7 cells. The treatment with oyster shell extract decreased the generation of intracellular reactive oxygen species dose dependently and increased antioxidant enzyme activities, such as SOD, catalase, GSH-px in LPS-stimulated macrophage cells. Oyster shell extract significantly suppressed the production of NO and also decreased the expressions of iNOS, COX-2 and NF-κB. Additionally, oyster shell extract significantly inhibited the production of IL-1ß, IL-6, and TNF-α in LPS-stimulated Raw 264.7 cells. Thus, these results showed that the oyster shell extract had an anti-inflammatory effect on LPS-stimulated Raw 264.7 cells.

Mutation spectra induced by adozelesin in the supF gene of human XP-A fibroblasts.

Adozelesin is a synthetic analog of the antitumor antibiotic, CC-1065, which alkylates N3 of adenine in the minor DNA groove in a sequence-specific manner. Here we tested the mutation spectra induced by adozelesin in the supF gene of human XP-A fibroblasts using a shuttle vector assay. Adozelesin primarily induces mutations via an A --> T transversion and a single base insertion. The A --> T transversion (43/59) was observed at the adenine alkylation site in the 5'-ATTTA* sequence (A* is the site of alkylation). The single base insertion (5/59) was observed at the 3'-side of the covalently modified adenine in the 5'-CTAAA* sequence. The results of this study suggest that the DNA alkylating sequence of adozelesin influences the type of DNA mutation.

Comparative study on the aflatoxin B1 degradation ability of rumen fluid from Holstein steers and Korean native goats.

The aflatoxin B1 degrading abilities of two different ruminants were compared in this study. One set of experiments evaluated the aflatoxin B1 degradation ability of different rumen fluid donors (steers vs. goats) as well as the rumen fluid filtration method (cheese cloth filtered vs. 0.45 microm Millipore) in a 2 x 2 factorial arrangement. Additional studies examined aflatoxin B1 degradation by collecting rumen fluid at different times (0, 3, 6, 9 and 12 h) after feeding. Cannulated Holstein steers (740 +/- 10 kg bw) and Korean native goats (26 +/- 3 kg bw) were fed a 60% timothy and 40% commercial diet with free access to water. Rumen fluid from Korean native goats demonstrated higher (p < 0.01) aflatoxin B1 degradability than Holstein steers. However, filtration method had no significant influence on degradability. In addition, aflatoxin degradation did not depend upon rumen fluid collection time after feeding, as no significant differences were observed. Finally, a comparison of two types of diet high in roughage found aflatoxin degradability in goats was higher with timothy hay opposed to rice straw, although individual variation existed. Thus, our findings showed the aflatoxin degradability is comparatively higher in goats compared to steers.