The Origin of Membrane Vesicles in Ram Seminal Plasma

The hypothesis tested in this study was that the membrane vesicles present in ram seminal plasma are of testicular origin, rather than being secreted by the accessory sex glands as has been previously reported for a number of species. Membrane vesicles were present in cellular extracts from reproductive organs and accessory sex glands of six rams, and in the seminal plasma of a further eight rams. When four of the latter rams were subjected to vasectomy, to isolate ejaculate contents to only the secretions of the accessory sex glands, the vesicles were largely eliminated from their ejaculates, while vesicles were still present in the ejaculates of the four control rams. The constituents of the cytoplasmic droplets and membrane vesicles derived from the seminal plasma were compared by transmission electron microscopy (TEM). Vesicles present in the cytoplasmic droplets were similar in morphology but smaller on average than those in the seminal plasma. It was concluded that the membrane vesicles in ram seminal plasma originate from either the cytoplasmic droplets, or a combination of vesicles from the droplets and the epididymis.     

Maxillary osteosarcoma in a prairie dog (Cynomys ludovicianus).

To date, few tumors have been identified in prairie dogs, with odontoma being the most common. Osteosarcoma has been documented in a wide range of species, including a number of rodents. In this case, a locally invasive maxillary osteosarcoma was diagnosed in a prairie dog. Gross examination revealed a pale, tan, lobulated, sessile maxillary mass extending ventrally into the oral cavity from the hard palate and the gingiva surrounding the upper right cheek teeth. The mass invaded the right nasal cavity and retrobulbar space causing exophthalmia. Microscopically, the mass consisted of densely packed spindle-shaped cells with occasional multinucleated giant cells. Brightly eosinophilic osteoid was multifocally scattered in the tumor mass. To the authors' knowledge, this is the first documented report of maxillary osteosarcoma in a prairie dog.     

Autologous Whole Ram Seminal Plasma and its Vesicle-free Fraction Improve Motility Characteristics and Membrane Status but not In Vivo Fertility of Frozen–Thawed Ram Spermatozoa

Motility characteristics (assessed subjectively and with computer-assisted semen analysis) and membrane status (after staining with chlortetracycline) of washed and non-washed frozen-thawed ram spermatozoa were evaluated after incubation in buffer and buffer containing autologous whole seminal plasma or one of its two fractions: the pellet of membrane vesicles obtained by ultracentrifugation (and used at three times normal protein concentration) or the vesicle-free supernatant fraction. Whole seminal plasma and supernatant, but not membrane vesicles, improved the motility characteristics of spermatozoa after 3 and 6 h of post-thaw incubation compared with the control buffer. Resuspension and incubation with whole seminal plasma, supernatant or membrane vesicles lowered the proportion of acrosome-reacted frozen-thawed spermatozoa compared with the control buffer. Unwashed frozen-thawed semen from three rams, incubated with autologous whole seminal plasma or its fractions and inseminated using cervical or intrauterine artificial insemination, had no effect on pregnancy rates of ewes in synchronized oestrus. However, fertility was higher after laparoscopic than cervical insemination (44.9 vs 12.3%, p < 0.001). In conclusion, resuspension and incubation of frozen-thawed ram spermatozoa in autologous whole seminal plasma or its vesicle-free supernatant fraction improved their motility characteristics and, with membrane vesicles, membrane status, but these benefits were not reflected in improved fertility after cervical or intrauterine insemination.     

Alteration in testicular cyclic AMP system in the rat following vasectomy.

Endogenous cyclic AMP levels and the activities of adenylate cyclase, cyclic AMP-dependent and independent protein kinases were examined in testes of mature rats bilaterally vasectomized for one, three and seven months. Although no significant alteration in testicular cyclic AMP was detected one month following vasectomy, marked decreases (by 55% and 32%, respectively) were seen three and seven months postvasectomy. Likewise, vasectomy also resulted in a significant decrease (by 25%) in the activity of testicular adenylate cyclase three and seven months after vasectomy. Although soluble cyclic AMP-dependent protein kinase activity remained unaffected three months postvasectomy, the activity of the cyclic nucleotide-dependent enzyme was significantly increased (by 21%) when compared to the sham-operated controls. Furthermore, while the protein kinase ratio (--cyclic AMP/+cyclic AMP) was decreased in animals vasectomized for three months, the ability of the enzyme to bind (3H) cyclic AMP in vitro was significantly enhanced (18%). Rats vasectomized for seven months showed similar biochemical alterations but the effects of this procedure were more pronounced. Moreover, while short-term vasectomy increased the responsiveness of seminiferous tubular adenylate cyclase to in vitro stimulation by follicle stimulating hormone, the activity of the enzyme was also increased (by 100%) in the presence of luteinizing hormone in vasectomized rats. These data raise the possibility that changes in testicular function seen following vasectomy may be related to the alterations in cyclic AMP metabolism as well as in the sensitivity of testicular adenylate cyclase to regulation by gonadotropins.     

Ordering of V2+, Mn2+, and Fe3+ Ions in Zoisite, Ca2Al3Si3O12(OH)

The presence of very small amounts of Mn(2+), V(2+), and Fe(3+) ions in zoisite can be easily detected by the electron paramagnetic resonance technique at room temperature. The Mn(2+) and Fe(3+) ions are completely ordered and are probably located in the Ca(1)- and Al(II)-sites, respectively, whereas the V(2+) ions probably occupy both Ca(1)- and Ca(2)-sites, with a preference for the Ca(1)-site.     

寄生荔枝蒂蛀虫的刻绒茧蜂属一新种(膜翅目:茧蜂科)

报道了茧蜂科刻绒茧蜂属一新种——荔枝蒂蛀虫刻绒茧蜂Glyptapanteles conopomorphae Tsang et You sp.nov.,记述刻绒茧蜂属属征,新种形态,与近缘种的区别,并有新种产地、寄主及模式标本保存地点.     

Common mechanism for repellents and attractants in bacterial chemotaxis

The migrational response of Salmonella typhimurium away from compounds such as phenol, indole, acetic acid, and leucine occurs because the bacteria tumble less frequently while descending gradients of repellents. This contrasts with their response of tumbling less frequently while ascending gradients of attractants. The results of competition experiments suggest that repellents, like attractants, operate through specific receptors, and the algebraic additivity experiments indicate that repellents and attractants utilize a common memory mechanism for taxis.     

HST2 mediates SIR2-independent life-span extension by calorie restriction

Calorie restriction (CR) extends the life span of numerous species, from yeast to rodents. Yeast Sir2 is a nicotinamide adenine dinucleotide (NAD+-dependent histone deacetylase that has been proposed to mediate the effects of CR. However, this hypothesis has been challenged by the observation that CR can extend yeast life span in the absence of Sir2. Here, we show that Sir2-independent life-span extension is mediated by Hst2, a Sir2 homolog that promotes the stability of repetitive ribosomal DNA, the same mechanism by which Sir2 extends life span. These findings demonstrate that the maintenance of DNA stability is critical for yeast life-span extension by CR and suggest that, in higher organisms, multiple members of the Sir2 family may regulate life span in response to diet.     

Predicting likelihood of in vivo chemotherapy response in canine lymphoma using ex vivo drug sensitivity and immunophenotyping data in a machine learning model

We report a precision medicine platform that evaluates the probability of chemotherapy drug efficacy for canine lymphoma by combining ex vivo chemosensitivity and immunophenotyping assays with computational modelling. We isolated live cancer cells from fresh fine needle aspirates of affected lymph nodes and collected post‐treatment clinical responses in 261 canine lymphoma patients scheduled to receive at least 1 of 5 common chemotherapy agents (doxorubicin, vincristine, cyclophosphamide, lomustine and rabacfosadine). We used flow cytometry analysis for immunophenotyping and ex vivo chemosensitivity testing. For each drug, 70% of treated patients were randomly selected to train a random forest model to predict the probability of positive Veterinary Cooperative Oncology Group (VCOG) clinical response based on input variables including antigen expression profiles and treatment sensitivity readouts for each patient's cancer cells. The remaining 30% of patients were used to test model performance. Most models showed a test set ROC‐AUC > 0.65, and all models had overall ROC‐AUC > 0.95. Predicted response scores significantly distinguished (P < .001) positive responses from negative responses in B‐cell and T‐cell disease and newly diagnosed and relapsed patients. Patient groups with predicted response scores >50% showed a statistically significant reduction (log‐rank P < .05) in time to complete response when compared to the groups with scores <50%. The computational models developed in this study enabled the conversion of ex vivo cell‐based chemosensitivity assay results into a predicted probability of in vivo therapeutic efficacy, which may help improve treatment outcomes of individual canine lymphoma patients by providing predictive estimates of positive treatment response.     

Degradation of green tea catechins in tea drinks

Green tea cateachins (GTC). namely (-) epicatechin (EC), (-) epicatechin gallate (ECG), (-) epigallocatechin (EGC), and (-) epigallocatechin gallate (EGCG), have been studied extensively for their wide-ranging biological activities. The goal of the present study was to examine the stability of GTC as a mixture under various processing conditions. The stability study demonstrated that GTC was stable in water at room temperature. When it was brewed at 98 degrees C for 7 h, longjing GTC degraded by 20%. When longjing GTC and pure EGCG were autoclaved at 120 degrees C for 20 min, the epimerization of EGCG to (-) gallocatechin gallate (GCG) was observed. The relatively high amount of GCG found in some tea drinks was most likely the epimerization product of EGCG during autoclaving. If other ingredients were absent, the GTC in aqueous solutions was pH-sensitive: the lower the pH, the more stable the GTC during storage. When it was added into commercially available soft drinks or sucrose solutions containing citric acid and ascorbic acid, longjing GTC exhibited varying stability irrespective of low pH value. This suggested that other ingredients used in production of tea drinks might interact with GTC and affect its stability. When canned and bottled tea drinks are produced, stored, and transported, the degradation of GTC must be taken into consideration.