Ages of prehistoric earthquakes revealed by cosmogenic chlorine-36 in a bedrock fault scarp at hebgen lake

Cosmogenic chlorine-36 reveals dates of the multiple prehistoric earthquakes that have produced a scarp on the Hebgen Lake fault. Apparent chlorine-36 ages are stratigraphically correct, follow a predicted theoretical pattern, and produce geologically reasonable model ages of 24, 20, 7.0, 2.6, 1.7, and 0.4 thousand years ago. This result demonstrates the feasibility of using cosmogenic chlorine-36 to extract paleoearthquake records from bedrock fault scarps.     

澳大利亚棉花黄萎病菌致病性鉴定研究

 在温室人工接种鉴定了澳大利亚16个棉花种植地区30个棉花黄萎病菌株的致病性.结果表明:根据人工接种5个棉花品种的抗感反应和病情指数,30个供试菌株划分为4种致病类型.致病类型I(3个菌株)具有较强的致病能力,致病类型Ⅳ(5个菌株)的致病能力较弱.致病类型Ⅱ(12个菌株)和致病类型Ⅲ(10个菌株)的致病能力中等,为澳大利亚棉花种植地区的主要菌系类型.     

Effect of Different Media and Protein Source on Equine Gametes: Potential Impact During In Vitro Fertilization

Equine in vitro fertilization (IVF) is still inconsistent. In the present work, we studied how modified Whitten's (MW) medium and Tissue Culture Medium 199 (TCM) added with Foetal Bovine Serum (FBS; 10% v/v) or Bovine Serum Albumin (BSA; 7 mg/ml) affected equine gametes to subsequently run IVF trials. Compact (Cp) and expanded (Ex) cumuli equine oocytes were matured and placed in TCM or MW supplemented with BSA or FBS for 18–20 h (no sperm added). In Ex oocytes, TCM‐199 added with FBS or BSA resulted in higher metaphase II (MII) rates (75.7% and 62.7%, respectively) than MW added with BSA (54%) or FBS (52.2%; p < 0.05); this was not observed for Cp oocytes. Equine sperm were capacitated in the same media at 10 × 10⁶ sperm/ml for 4 h at 37°C; total motility and protein tyrosine phosphorylation (PY) were evaluated. While motility remained unchanged, TCM or MW added with FBS enhanced the number of sperm showing PY‐stained tails (25 ± 4.8% and 31 ± 6.6%; mean ± SEM, respectively) over BSA supplemented media (3 ± 1.2% and 11.7 ± 1.1%) for TCM and MW (p < 0.05). In view of the previous results, sperm were capacitated in TCM + FBS and MW + BSA (control); IVF trials were run in the same media supplemented with 200 ng/ml of progesterone, but no fertilization occurred. Our results show that TCM + FBS enhances Ex equine oocyte's meiotic competence over MW + BSA and TCM or MW added with FBS successfully induce equine PY over media supplemented with BSA.     

Production of Homomatromorphs through Pollen Treatment in Pisum sativum L.

The occurrence of homozygous matromorphic progenis in Pisum sativum L. has, been assessed by using heterozygous female parents in intervarietal and intergeneric crosses. The pollen was subjected to three treatments, i.e. prickle pollination (delayed), gamma irradiation and giibberellic acid (GA₃) application, The genetic status of the induced matromorphic progeny was determined by using, multiple gene markers. The frequency or occurrence of homomatromorphs was 3 to 7 per cent, which needs to be increased by pod, ovule or embryo culture, respectively.     

Black-hair follicular dysplasia in a New Zealand Huntaway dog

CASE HISTORY: A 6-year-old intact male New Zealand Huntaway dog had slowly progressive alopecia that was first observed at 12 weeks of age.

CLINICAL FINDINGS: Patchy alopecia was confined to the black-haired areas of the body, and was most evident on the head and dorsum of the body; tan-haired areas of skin appeared normal. Histological examination of black-haired skin revealed distended melanocytes and large aggregates of melanin within, and surrounding, the hair follicles and the epidermis. Macrophages distended with melanin were also visible within the perifollicular and superficial dermis, and follicular lumina were often plugged by keratin that contained aggregates of melanin. The follicles were dysplastic and few hair shafts were visible emerging from follicular infundibula within the sections.

DIAGNOSIS: The clinical and histological findings were consistent with black-hair follicular dysplasia (BHFD).

CLINICAL RELEVANCE: This is the first report of BHFD in a dog in New Zealand, and is the first report in a Huntaway. The most significant effect of BHFD is a predisposition to follicular plugging and secondary bacterial skin infections. Due to the hereditary nature of the follicular dysplasias, breeding from affected dogs should be discouraged. Histological examination of the skin is required to differentiate between the different follicular dysplasias as well as differentiating between follicular dysplasia and follicular atrophy due to endocrinopathy.     

Competitive exclusion of Yersinia enterocolitica biotype 4, serotype O:3 by Yersinia enterocolitica biotype 1A,serotype O:6,30 in tissue culture and in pigs

AIMS: To study the adhesion properties of a biotype 4, serotype O:3 (human pathogenic) strain of Yersinia enterocolitica and to determine if adhesion in vitro and colonisation in vivo can be prevented by competition with a biotype 1A, serotype O:6,30 (non-pathogenic) strain. To study interaction between Y. enterocolitica biotype 4, serotype O:3 and cultured epithelial cells using the synthetic tripeptide arginine-glycine-aspartic acid (RGD).

METHODS: The human intestinal epithelial (HEp-2) cell line was used for in vitro studies. Inocula of Y. enterocolitica biotype 4, serotype O:3 radiolabelled using tritium were incubated with HEp-2 cells and RGD tripeptide, or with Y. enterocolitica biotype 1A, serotype O:6,30 sequentially or concurrently, then washed and lysed, and radioactivity measured to determine the effect of RGD on adhesion, and competitive exclusion of pathogenic by non-pathogenic bacteria. For in vivo studies, two groups of 5-week-old piglets (n=5/group) were sequentially inoculated orally with 5x10⁹ colony forming units (cfu) of either a non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica followed by a pathogenic biotype 4, serotype O:3 strain, or vice versa. Pigs were monitored for carriage of strains using bacterial culture and a multiplex polymerase chain reaction (PCR).

RESULTS: The RGD tripeptide significantly inhibited adherence of the pathogenic Y. enterocolitica strain to cultured epithelial cells, suggesting that adhesion involved the RGD tripeptide sequence. The non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica prevented adhesion of the pathogenic strain to cells in vitro when allowed to adhere first. Pathogenic Y. enterocolitica was consistently isolated from rectal swabs from 80-100% of pigs on all sampling occasions but not from oral swabs after 14 days in pigs first inoculated with the non- pathogenic strain or at 26 days in pigs first inoculated with the pathogenic strain.

CONCLUSIONS: A non-pathogenic strain of Y. enterocolitica reduced adhesion of a human pathogenic strain in vitro but not in vivo.