INDIGENOUS POULTRY FEED MICROFLORA RESPONSE TO ETHYL ALCOHOL AND BUFFERED PROPIONIC ACID ADDITION

The present study was designed to compare ethyl alcohol with buffered propionic acid feed treatment on the survival of indigenous poultry feed bacteria and fungi. The aerobic bacterial poultry feed populations were not substantially reduced by either ethyl alcohol or buffered propionic acid treatments. Likewise, indigenous poultry feed fungal populations also were not markedly reduced by buffered propionic acid treatment of the feed but fungal poultry feed populations exposed to ethyl alcohol treatments were significantly lower (P<0.05) than fungal populations recovered from either control and buffered propionic acid treated feeds. Ethyl alcohol treatment may have potential for reducing fungal contamination in poultry feed.     

Oxytocin-induced release of prostaglandin F2 alpha in postpartum beef cows: comparison of short versus normal luteal phases

The first postpartum ovulation after early weaning of calves (30 35 days of age) from cows is normally followed by a short luteal phase (6 10 days) unless the animals are pretreated with a progestogen (e.g. norgestomet). Reduced luteal lifespan in cattle is reportedly due to the premature release of a luteolysin (presumably prostaglandin F2 alpha [PGF2 alpha]). Therefore, the objective was to determine if oxytocin-induced release of PGF2 alpha (measured by the stable PGF2 alpha metabolite, 15-keto-13,14-dihydro PGF2 alpha [PGFM]) was greater for cows having a short compared to a normal luteal phase on Day 5 following the first postpartum estrus (Day 0). Thirty postpartum beef cows were randomly assigned into three groups (n = 10 per group) expected to have short (Short d 5) or normal (Norgestomet d 5 and Norgestomet d 16) luteal phases. Cows in Norgestomet d 5 and d 16 groups received Norgestomet (progestogen) implants for 9 days beginning 21 23 days postpartum. On Day 5 (Short d 5 and Norgestomet d 5) or Day 16 (Norgestomet d 16) following first postpartum estrus, each animal was injected (i.v.) with 100 IU oxytocin. In addition, cows in the Short d 5 group were subdivided into two groups following second estrus (normal luteal phase, n = 5 per group) to receive 100 IU oxytocin on Day 5 (Normal d 5) or 16 (Normal d 16), respectively. Estrous cycle length (means +/- SE) for cows in the Short d 5 group (8.7 +/- 0.4 days) was shorter (p less than 0.01) than for cows in all other groups (21.1 +/- 0.3 days).(ABSTRACT TRUNCATED AT 250 WORDS)     

Secretory patterns of LH and FSH during development and hypothalamic and hypophysial characteristics following development of steroid-induced ovarian follicular cysts in dairy cattle

Two experiments were conducted to (1) investigate developmental endocrinology of ovarian follicular cysts (cysts) in cattle and (2) evaluate effects of cysts on hypothalamic and hypophysial characteristics. Cysts were induced with oestradiol-17 beta (15 mg) and progesterone (37.5 mg) dissolved in alcohol and injected s.c. twice daily for 7 days. Cysts were defined as the presence of follicular structures (which may or may not have been the same structure) of 2.0 cm in diameter or greater that were present for 10 days without ovulation and corpus luteum development. In Exp. 1,22 non-lactating, non-pregnant Holstein cows were allocated to 3 groups. Beginning on Day 5 (oestrus = Day 0) of the oestrous cycle, 7 cows (Controls) were treated with twice daily s.c. injections of ethanol (2 ml/injection) for 7 days. Luteolysis was then induced with PGF-2 alpha and blood samples were collected daily every 15 min for 6 h from the morning after the PGF-2 alpha injection (Day 13) until oestrus. Steroids to induce cysts were injected as previously described into the remaining cows (N = 15). Three blood samples were collected at 15-min intervals every 12 h throughout the experimental period. Additional blood samples were collected every 15 min for 6 h on a twice weekly basis. After steroid injections, follicular and luteal structures on ovaries were not detected via rectal palpation for a period of 36 +/- 4 days (static phase). Then follicles developed which ovulated within 3-7 days (non-cystic; N = 7) or increased in size with follicular structures present for 10 days (cystic; N = 8). Mean (+/- s.e.m.) concentrations of LH, FSH, oestradiol-17 beta and progesterone in serum remained low and were not different during the static phase between cows that subsequently developed cysts or ovulated. During the follicular phase, mean serum concentration of LH (ng/ml) was higher (P less than 0.1) in cows with cysts (2.9 +/- 0.2) than in cows without cysts (1.1 +/- 0.1) or control cows (1.4 +/- 0.2). In addition, LH pulse frequency (pulses/6 h) and amplitude (ng/ml) were higher (P less than 0.1) in cows with cysts (3.6 +/- 0.3 and 2.2 +/- 0.3, respectively) than in non-cystic (2.3 +/- 0.2 and 1.0 +/- 0.2, respectively) and control (1.8 +/- 0.1 and 1.1 +/- 0.2, respectively) groups during the follicular phase. There were no differences in the FSH, oestradiol-17 beta or progesterone characteristics in cows of any of the 3 groups during the follicular phase.(ABSTRACT TRUNCATED AT 400 WORDS)     

质粒超螺旋比例对其细胞转染效率及表达的影响

检测质粒开环、闭环比例不同时对其细胞转染效率及表达的影响。构建携带人肝细胞生长因子基因的质粒(pcDNA3-HGF)及携带LacZ报告基因的质粒(pcDNA3-LacZ),用核酸纯化试剂盒提取开环、闭环比例不同的质粒,然后用LipofectAMINE介导它们分别转染NIH3T3细胞,采用X-Gal染色和ELISA法分别观察转染效率和表达活性。结果表明,用超螺旋比例分别为85.45%和48.44%的质粒pcDNA3-LacZ转染生长旺盛的NIH3T3细胞,48h检测转染效率分别为23.4%±3.8%和9.3%±2.5%,前者约是后者的2.5倍。用超螺旋比例分别为93.28%和40.53%的质粒pcDNA3-HGF转染1×106NIH3T3细胞,ELISA法检测48h细胞培养上清中HGF的表达量分别为46.5±6.3ng和25.6±4.2ng,前者是后者的1.8倍。初步认为质粒开环、闭环比例不同对其细胞转染效率及表达有一定影响,超螺旋比例高时其转染效率及表达量较高。     

Recombinant <Emphasis Type="Italic">Escherichia coli</Emphasis> produces tailor-made biopolyester granules for applications in fluorescence activated cell sorting: functional display of the mouse interleukin-2 and myelin oligodendrocyte glycoprotein

Background  

Fluorescence activated cell sorting (FACS) is a powerful technique for the qualitative and quantitative detection of biomolecules used widely in both basic research and clinical diagnostic applications. Beads displaying a specific antigen are used to bind antibodies which are then fluorescently labelled using secondary antibodies. As the individual suspension bead passes through the sensing region of the FACS machine, fluorescent signals are acquired and analysed. Currently, antigens are tediously purified and chemically cross-linked to preformed beads. Purification and coupling of proteins often renders them inactive and they will not be displayed in its native configuration. As an alternative, we genetically engineered Escherichia coli to produce biopolyester (polyhdroxyalkanoate=PHA) granules displaying diagnostically relevant antigens in their native conformation and suitable for FACS analysis.     

MicroRNAs show a wide diversity of expression profiles in the developing and mature central nervous system

Background  

MicroRNA (miRNA) encoding genes are abundant in vertebrate genomes but very few have been studied in any detail. Bioinformatic tools allow prediction of miRNA targets and this information coupled with knowledge of miRNA expression profiles facilitates formulation of hypotheses of miRNA function. Although the central nervous system (CNS) is a prominent site of miRNA expression, virtually nothing is known about the spatial and temporal expression profiles of miRNAs in the brain. To provide an overview of the breadth of miRNA expression in the CNS, we performed a comprehensive analysis of the neuroanatomical expression profiles of 38 abundant conserved miRNAs in developing and adult zebrafish brain.     

Availability of and access to critical habitats in regulated rivers: effects of low-head barriers on threatened lampreys

1.  Conservation of freshwater animal populations requires their access to, as well as sufficient availability of, critical habitats, such as those for reproduction. Abundant small-scale barriers may cause extensive fragmentation of freshwater habitat but, by comparison to larger structures their effects are rarely considered by catchment managers. The relationship between the distribution of, and access to, spawning habitat in a regulated river, characterized by abundant small barriers, was examined for river lamprey Lampetra fluviatilis , a threatened migratory fish.
2.  Telemetry of adult lamprey in the River Derwent, North East England was used to quantify upriver migration and access to spawning habitat, together with surveys of spawning habitat availability and spawning activity between 2002 and 2007.
3.  Access in to the Derwent appeared severely restricted by a tidal barrage, beyond which lamprey migrated rapidly in unobstructed reaches. Of all lamprey tagged in the lower 4 km of river, or ascending the barrage, 64% and 17% passed the first and second weirs respectively, with high flows crucial for this. Although over 98% of lamprey spawning habitat occurred more than 51 km upstream, on average just 1.8% of river lamprey spawners were recorded there.
4.  In order to protect or rehabilitate species or species assemblages, greater attention needs to be paid to the relative spatial distribution of low-head barriers and the resultant availability of key habitats within individual catchments. This is particularly important given the renewed emphasis internationally on low-head hydropower solutions as a source of renewable energy, and the rapid growth in numbers of low-head barriers in many catchments.     

Chemopreventive and renal protective effects for docosahexaenoic acid (DHA): implications of CRP and lipid peroxides

Background

The fish oil-derived ω-3 fatty acids, like docosahexanoic (DHA), claim a plethora of health benefits. We currently evaluated the antitumor effects of DHA, alone or in combination with cisplatin (CP) in the EAC solid tumor mice model, and monitored concomitant changes in serum levels of C-reactive protein (CRP), lipid peroxidation (measured as malondialdehyde; MDA) and leukocytic count (LC). Further, we verified the capacity of DHA to ameliorate the lethal, CP-induced nephrotoxicity in rats and the molecular mechanisms involved therein.

Results

EAC-bearing mice exhibited markedly elevated LC (2-fold), CRP (11-fold) and MDA levels (2.7-fold). DHA (125, 250 mg/kg) elicited significant, dose-dependent reductions in tumor size (38%, 79%; respectively), as well as in LC, CRP and MDA levels. These effects for CP were appreciably lower than those of DHA (250 mg/kg). Interestingly, DHA (125 mg/kg) markedly enhanced the chemopreventive effects of CP and boosted its ability to reduce serum CRP and MDA levels. Correlation studies revealed a high degree of positive association between tumor growth and each of CRP (r = 0.85) and leukocytosis (r = 0.89), thus attesting to a diagnostic/prognostic role for CRP. On the other hand, a single CP dose (10 mg/kg) induced nephrotoxicity in rats that was evidenced by proteinuria, deterioration of glomerular filtration rate (GFR, -4-fold), a rise in serum creatinine/urea levels (2–5-fold) after 4 days, and globally-induced animal fatalities after 7 days. Kidney-homogenates from CP-treated rats displayed significantly elevated MDA- and TNF-α-, but reduced GSH-, levels. Rats treated with DHA (250 mg/kg, but not 125 mg/kg) survived the lethal effects of CP, and showed a significant recovery of GFR; while their homogenates had markedly-reduced MDA- and TNF-α-, but -increased GSH-levels. Significant association was detected between creatinine level and those of MDA (r = 0.81), TNF-α ) r = 0.92) and GSH (r = -0.82); implying causal relationships.

Conclusion

DHA elicited prominent chemopreventive effects on its own, and appreciably augmented those of CP as well. The extent of tumor progression in various mouse groups was highly reflected by CRP levels (thus implying a diagnostic/prognostic role for CRP). Further, this study is the first to reveal that DHA can obliterate the lethal CP-induced nephrotoxicity and renal tissue injury. At the molecular level, DHA appears to act by reducing leukocytosis, systemic inflammation, and oxidative stress.     

Secretory patterns of LH and FSH and follicular growth following administration of PGF(2)alpha during the early luteal phase in cattle

Two studies were conducted to determine the changes in gonadotropin secretion associated with growth and development of the largest follicle and the ability of the largest ovarian follicle present on Day 5 following estrus to ovulate if luteal regression is induced. In both studies, cows received either saline (i.m.) or prostaglandin F(2)alpha (PGF(2)alpha; 25 mg i.m.) on the fifth day post estrus. Frequency of LH pulses declined (P<0.01) with increasing day of cycle, while pulse amplitude and duration increased (P<0.05) in saline-treated cows. In PGF(2)alpha-treated cows, LH remained as high frequency-low amplitude pulses. Secretory patterns of FSH were similar between the two groups. In Experiment 2, the largest ovarian follicle present was marked around its periphery with sub-epithelial injections of charcoal. In saline-treated cows, the size of the charcoal marked follicles generally decreased, indicating atresia. A corpus luteum was present within the area of a previously marked follicle in three PGF(2)alpha-treated cows. The size of the marked follicles either decreased or increased in the remaining PGF(2)alpha-treated cows, with ovulation occurring at a different site. In summary, PGF(2)alpha-induced luteal regression on the fifth day of estrus subsequently alters the frequency, amplitude and duration of LH pulses, but not FSH pulses, and the largest follicle present on Day 5 either increases or decreases in size or ovulates when PGF(2)alpha is given on Day 5 following estrus.