Ovarian follicular development in Holstein cows following synchronisation of oestrus with oestradiol benzoate and an intravaginal progesterone releasing insert for 5-9 days and duration of the oestrous cycle and concentrations of progesterone following ovulation

The aim of this study was to determine if the duration of treatment with an intravaginal progesterone releasing insert (IVP(4)) after treatment with oestradiol benzoate (ODB) at the time of insertion and 24 h after removal would affect selected variables including: size of ovarian follicles at the time of removal of inserts, diameter of ovulatory follicles, plasma concentrations of progesterone following ovulation, and duration of the following oestrous cycle. Characteristics of oestrus at a synchronised and spontaneous oestrus were also monitored. Non-lactating Holstein cows were synchronised with an IVP(4) for 5 (n = 10), 7 (n = 10), 8 (n = 9) or 9 (n = 9) days together with injections of ODB at device insertion (2 mg) and 24 h after removal (1 mg). Ultrasonography showed no significant effect of treatment on the day of emergence of preovulatory follicles relative to the day of removal of inserts (overall mean = -4.22 +/- 0.58; P = 0.15) for cows that ovulated within 120 h insert removal (n = 36). Treatment with ODB and an IVP(4) for 5 days reduced the diameter of preovulatory follicles at the time of removal of inserts and for the following 2 days compared to cows treated for 7-9 days (mean difference 2.56 +/- 1.15 mm; P = 0.033) but did not reduce the diameter of the ovulatory follicle (P = 0.21). Day of emergence relative to removal of inserts was associated with the diameter of the ovulatory follicle (R2 = 0.69; P < 0.001). Concentrations of progesterone and the diameter of the corpus luteum following ovulation were not affected by treatment (P > 0.20), but were affected by the diameter of the ovulatory follicle (P < 0.01). Diameter of the ovulatory follicle did not affect interoestrous and interovulatory intervals (P > 0.40). We conclude that treatment with an IVP(4) for 5 compared to 7-9 days with ODB administered at device insertion, and 24 h after removal reduced the diameter of preovulatory follicles at the time of removal of the insert but did not reduce the diameter of the ovulatory follicle or concentrations of progesterone in plasma. Emergence of preovulatory follicles closer to the time of removal of inserts reduced the diameter of the ovulatory follicle when oestrus was induced with ODB. Ovulation of smaller follicles reduced concentrations of progesterone in plasma following ovulation but did not affect oestrous cycle duration.     

Ovarian follicular wave characteristics in alpacas

The objectives were to describe in detail ovarian follicular growth characteristics and to establish the interval between successive large follicles in unmated alpacas. The ovarian follicular status of 16 non-pregnant, non-lactating mature alpacas was recorded using ultrasound every second day for between 46 and 100 days. An inverse relationship was observed between the diameter of the largest follicle and the total number of follicles indicating that follicular growth in alpacas occurs in waves. There were 15/38 (39%) inter-wave intervals of 12 days and 12/38 (32%) intervals of 16 days. The maximum follicular diameter in each follicular wave was 8.8±0.3 mm (n=38). Inter-wave intervals of longer duration were associated with a larger maximum follicle diameter (P<0.001). However, the growth rate of dominant follicles was consistent over the first 10 days after emergence. They reached a diameter capable of ovulation by this time, regardless of subsequent inter-wave interval. The latter observation suggested that the optimal time of mating might be predicted in alpacas, provided that the emergence of ovarian follicular waves was controlled.     

Flowering of the grass Lolium perenne: effects of vernalization and long days on gibberellin biosynthesis and signaling

Almost 50 years ago, it was shown that gibberellin (GA) applications caused flowering in species normally responding to cold (vernalization) and long day (LD). The implication that GAs are involved with vernalization and LD responses is examined here with the grass Lolium perenne. This species has an obligatory requirement for exposure to both vernalization and LD for its flowering (inflorescence initiation). Specific effects of vernalization or LD on GA synthesis, content, and action have been documented using four treatment pairs: nonvernalized or vernalized plants exposed to short days (SDs) or LDs. Irrespective of vernalization status, exposure to two LDs increased expression of L. perenne GA 20-oxidase-1 (LpGA20ox1), a critical GA biosynthetic gene, with endogenous GAs increasing by up to 5-fold in leaf and shoot. In parallel, LD led to degradation of a DELLA protein, SLENDER (within 48 h of LD or within 2 h of GA application). There was no effect on GA catabolism or abscisic acid content. Loss of SLENDER, which is a repressor of GA signaling, confirms the physiological relevance of increased GA content in LD. For flowering, applied GA replaced the need for LD but not that for vernalization. Thus, GAs may be an LD, leaf-sourced hormonal signal for flowering of L. perenne. By contrast, vernalization had little impact on GA or SLENDER levels or on SLENDER degradation following GA application. Thus, although vernalization and GA are both required for flowering of L. perenne, GA signaling is independent of vernalization that apparently impacts on unrelated processes.     

Effects of administering progesterone at selected intervals after insemination of synchronized heifers on pregnancy rates and resynchronization of returns to service

In 3 separate trials at 2 locations, dairy heifers (n = 396) were treated with a Controlled Internal Drug Release (CIDR) progesterone device for 9 d. On Day 7 of CIDR treatment, all heifers were injected with PGF(2alpha). Synchronized estruses were detected using a tailpaint and chalk (TPC) scoring system. An animal's tailhead was painted at device insertion, and this strip was covered with a contrasting color of chalk at device removal. Over all trials, 85.1% of the heifers were detected in estrus and were inseminated at 48 or 72 hours after CIDR removal. These synchronized and inseminated heifers were divided into the following treatment groups: 1) untreated controls, receiving no further treatment (n = 138); 2) post-insemination progesterone supplementation with a new (n = 59) or used (n = 29) CIDR device for Days 1 to 8 or 2 to 9, respectively, following insemination; or 3) resynchronization of return to service with a used CIDR device for Days 17 to 22 after insemination (n = 112). The pregnancy rate to first insemination in the control and resynchronized groups (Groups 1 and 3) was 46.4%, but decreased to 18.2% with the post-insemination progesterone supplementation. Resynchronization of returns to service (estrus detected 1 to 4 d following removal of second CIDR) occurred in 58.9% of all nonpregnant heifers in Group 3. In summary, CIDR devices used in conjunction with PGF(2alpha) effectively synchronize estrus in dairy heifers. Progesterone supplementation within 2 d of first insemination for 7 d suppressed fertility. Used CIDR devices inserted for Days 17 to 22 after first insemination resynchronized heifers not pregnant to first insemination.     

Some pink yeasts associated with softening of olives

Pink yeasts identified as Rhodotorula glutinis var. glutinis, R. minuta var. minuta, and R. rubra produce polygalacturonases which cause a slow softening of olive tissue. Both pectin methyl esterase and polygalacturonase are produced when cultures are grown in appropriate media. Crude, cell-free dialyzed enzyme preparations measured viscosimetrically exhibited optimal activity on sodium polygalacturonate at pH 6.0 and 40 C, and were active in the range of pH 4.0 to 9.0 and 10 to 50 C. Cultures grown in sterilized olives and brine at pH 4.0 with sterile glucose added aseptically caused a slow softening of tissue as measured with a Christel texturometer. Similar results were obtained when crude, cell-free enzyme preparations were added to olives in buffer solution at pH 6.0 with Merthiolate. Commercial control of these yeasts is easy if anaerobic conditions can be provided. Otherwise, the industry has to resort to manual removal of the film from the brine surface, either by skimming or by flagellation.     

Monoclonal antibodies to 13-deoxy-gibberellins

The production and characterization of two high affinity rat monoclonal antibodies to 13-deoxy-gibberellins is described. Hybrid myelomas were derived from rats immunized with an immunogenic keyhole limpet hemocyanin-gibberellin conjugate, linked at carbon-3 to gibberellin A₄ via a hemisuccinate bridge. The selected monoclonal antibodies were characterized by a competitive radioimmunoassay.     

Subcellular Localizations of Two Dolichos biflorus Lectins

The subcellular localizations of the Dolichos biflorus seed lectin and the structurally related lectin (cross-reactive material [CRM]) from the stems and leaves of this plant were determined by immunofluorescence, immunocytochemistry, and cell fractionation procedures. Subcellular fractionation of the cotyledons using a nonaqueous procedure to minimize disruption of the protein bodies showed that the majority of the seed lectin was associated with the protein body fraction and some lectin was also present in the starch granules. Immunofluorescence and immunocytochemistry at the light microscopic level showed that the seed lectin was mainly localized at the peripheries of these organelles. Lectin was also found in the cytoplasm of the cells, although the amount appeared to be dependent upon the degree of protein body disruption.

Immunofluorescence and immunocytochemistry studies of the stem and leaf lectin (CRM) indicated that a significant portion of this lectin may be associated with the cell walls, although lectin was also seen in the cytoplasm of plasmolyzed cells. Extraction and cell fractionation studies showed that a large portion of the CRM is readily solubilized and most of the remainder is pelleted at 1000g. The CRM can be extracted from these pellets by treatment with cellulase and pectinase; other reagents such as NaCl, detergents, and EDTA could also release significant amounts of CRM. These studies suggest that the CRM is noncovalently bound to the cell walls. A comparison of the distribution of exogenously supplied [¹²⁵I]CRM with the endogenous CRM during extraction and cell fractionation indicates that soluble CRM is not adsorbed to the 1000g pellet during fractionation.

The different subcellular distributions of these two structurally related lectins suggest that different tissues of the same plant may utilize lectins for different functions.

     

Serologic survey for Brucella spp., phocid herpesvirus-1, phocid herpesvirus-2, and phocine distemper virus in harbor seals from Alaska, 1976-1999

Harbor seals (Phoca vitulina richardsi) were captured in the coastal regions of Southeast Alaska, Gulf of Alaska, Prince William Sound (PWS), and Kodiak Island during 1976-1999. Blood was collected from 286 seals. Sera were tested for evidence of exposure to Brucella spp., phocid herpesvirus-1 (PhoHV-1), phocid herpesvirus-2 (PhHV-2), and phocine distemper virus (PDV). Antibody prevalence rates were 46% (46/100) for Brucella spp., 93% (225/243) for PhoHV-1, 0% (0/286) for PhHV-2, and 1% (2/160) for PDV. Antibody prevalence for Brucella spp. was directly related to host age. Antibody prevalence for PhoHV-1 was higher in PWS as compared to the other three regions. No evidence of mortality attributable to these four agents was observed during the course of this study. Based on the results of this survey, none of these agents is considered a significant mortality factor in harbor seals from the four regions of coastal Alaska included in the study.