Efficacy of PGF(2alpha) to synchronize estrus in water buffalo cows (Bubalus bubalis) is dependent upon plasma progesterone concentration,corpus luteum size and ovarian follicular status before treatment

This study was conducted to identify factors affecting PGF(2alpha) efficacy to synchronize estrus in water buffalo cows. After detection of a corpus luteum (CL) by rectal palpation, cows were treated (im) with dinoprost (12.5, 25 or 50mg) or D(+) cloprostenol (75, 150 or 300 microg) in a total of 66 treatments. Blood samples were collected 0, 24 and 48 h after treatment and ultrasound examinations and observations for estrus were performed daily to the day of ovulation or to 6 days after treatment. No PGF(2alpha) dose-response pattern was observed and overall rates of luteal regression (progesterone <1.0 ng/ml at 48 h), estrus, no detected behavioral estrus with ovulation occurring, and ovulation were 71.2, 36.4, 19.7 and 54.5%, respectively. To analyze plasma progesterone concentrations and ovarian dynamics, cows were divided in three groups according to their response to treatment. Cows that failed to have ovulations from a follicle after treatment (Group A, n = 30) had (P < 0.05) a lower plasma progesterone concentration (2.98 ng/ml) and smaller CL area (CLA; 187.3 mm(2)) before treatment as compared with cows that had an ovulation from a follicle (4.43 ng/ml and 223.7 mm(2), respectively; Groups B and C, n = 36). In cows that failed to ovulate, plasma progesterone concentration decreased in the first 24 h, but did not decline further and was >1.0 ng/ml 48 h after treatment. Moreover, no significant change in CLA after treatment was detected, indicating that treatment induced only partial luteolysis. In cows that ovulated, plasma progesterone concentration and CLA decreased continuously from treatment to ovulation (consistent with complete luteolysis). Threshold values of 2.8 ng/ml for plasma progesterone concentration and 189 mm(2) for CLA were identified as the best predictors of ovulation before treatment (83.3 and 80.6% sensitivity and 58.6 and 65.5% specificity, respectively, with positive and negative predictive values around 71%). When the origin of the ovulatory follicle was investigated, the interval from treatment to ovulation was shorter (91.9 versus 113.3 h; P < 0.05), and the ovulatory follicle had a slower growth rate (1.02 versus 1.55 mm per day; P < 0.005), a lesser increase in diameter from treatment to ovulation (4.7 versus 8.0 mm; P < 0.001), and a greater maximum diameter (13.2 versus 12.1 mm; P < 0.05) in cows that ovulated from the largest follicle present in the ovary before treatment (Group B, n = 27) compared with cows that ovulated from the second largest follicle present in the ovary before treatment (Group C, n = 9). In summary, the efficacy of PGF(2alpha) for causing luteolysis and synchronizing estrus and ovulation in buffalo cows was dependent upon plasma progesterone concentration, CL size and ovarian follicular status before treatment.     

Effect of age and genetic group on characteristics of the scrotum,testes and testicular vascular cones,and on sperm production and semen quality in AI bulls in Brazil

The objectives were to determine the effects of age and genetic group on characteristics of the scrotum, testes and testicular vascular cones (TVC), and on sperm production and semen quality in 107 Bos indicus, B. taurus and cross-bred bulls at three artificial insemination (AI) centers in Brazil. In addition, predictors of sperm production and semen quality were identified. In general, scrotal circumference (SC), scrotal shape score, scrotal neck perimeter, and testicular size (length, width and volume) increased (P < 0.05) with age. Although there were no significant differences among genetic groups for SC or testicular size, B. indicus bulls had the least pendulous scrotal shape, the shortest scrotal neck length, and the greatest scrotal neck perimeter (P < 0.05). Fat covering the TVC was thinner (P < 0.05) in bulls < or = 36 months of age and in B. taurus bulls than in older bulls and B. indicus bulls, respectively. Age and genetic group did not affect testicular ultrasonic echotexture. B. indicus bulls tended (P < 0.1) to have the lowest average scrotal surface temperature (SST). In general, ejaculate volume, total number of spermatozoa and number of viable spermatozoa increased (P < 0.05) with age. However, there was no significant effect of age on sperm concentration, motility, major and total defects. The proportion of spermatozoa with minor defects was highest (P < 0.05) in bulls 37-60 months of age. B. indicus bulls had higher (P < 0.01) sperm concentration, total number of spermatozoa and number of viable spermatozoa than B. taurus bulls, with intermediate values for cross-bred bulls. Increased sperm production was associated with increased testicular volume, SC, TVC fat cover, and SST top-to-bottom gradient. Decreased semen quality was associated with increased SC and bottom SST, and decreased scrotal shape, scrotal neck perimeter and vascular cone diameter. In summary, age and genetic group affected the characteristics of the scrotum, testes, and TVC, sperm production and semen quality. In addition, characteristics of the scrotum, testes and TVC were associated with sperm production and semen quality in bulls and could be assessed for breeding soundness evaluation.     

Steady-state luminescence investigation of the binding of Eu(III) and Tb(III) ions with synthetic peptides derived from plant thionins

This work reports Eu(III) and Tb(III) luminescence titrations in which the lanthanide ions were used as spectroscopic probes for Ca(II) ions to determine the metal binding ability of Ac-NESVKEEGGW-NH(2) and Ac-NESVKEDGGW-NH(2). These decapeptides correspond to the putative calcium binding region of the plant antifungal proteins SI-alpha1 from Sorghum bicolor and of Zeathionin from Zea mays, respectively. The luminescence spectra for the Eu(III)-decapeptide system (red emission) with the excitation at the Trp band at 280 nm showed an enhancement of the intensities of the 5D(0)-->7F(J) transitions (where J=0-4) with increments of Eu(III) ion concentration. The photoluminescence titration data of the terbium ion (green emission) in the decapeptide solutions showed intensification of the 5D(4)-->7F(J) transitions (J=0-6), similar to that observed for the Eu(III) ion. Thus, energy transfer from Ac-NESVKEEGGW-NH(2) and Ac-NESVKEDGGW-NH(2) to the trivalent lanthanide ions revealed that these peptides are capable of binding to these metal ions with association constants of the order of 10(5) M(-1). The amino acid derivative Ac-Trp-OEt also transferred energy to Tb(III) and Eu(III) ions as judged from the quenching of tryptophan luminescence. However, the energy transfers were significantly lower. Taken together the luminescence titration data indicated that Ac-NESVKEEGGW-NH(2) and Ac-NESVKEDGGW-NH(2) bind efficiently to both trivalent lanthanide ions and that these ions may be used as probes to distinguish an anionic peptide from a neutral amino acid derivative.     

Prevalence of cagA and vacA genes in isolates from patients with Helicobacter pylori-associated gastroduodenal diseases in Recife, Pernambuco, Brazil

Geographical differences in the prevalence of Helicobacter pylori genes and their association with disease severity have been identified. This study analyzes the prevalences of the cagA gene and alleles of the vacA gene in H. pylori-associated gastroduodenal diseases in isolates from Recife, PE, Brazil. Gastric biopsy of 61 H. pylori-positive patients were submitted to DNA extraction and gene amplification by polymerase chain reaction. Among the 61 patients, 21 suffered from duodenal ulcer (DU) and 40 from gastritis (GT). The prevalence of H. pylori strains harbouring the cagA gene was higher in the DU group (90.5%) than in the GT group (60%) (p=0.02). The vacA gene was amplified in 56 out of 61 biopsies, of which 43 (76.8%) contained bacteria carrying the s1 allele and 13 (23.2%) the s2. However, the prevalence of the vacA s1 genotyping was the same in either DU or GT group. The majority of the s1-typed strains, 39 (90.7%) out of 43, were subtype s1b. In resume there was a strong association between the H. pylori cagA+ gene and DU. However, there were no differences between the DU and GT groups in relation to the vacA s1 and s2 alleles distribution, albeit the subtype s1b was predominant.     

Shift work at a modern offshore drilling rig

The oil and gas exploration and production offshore units are classified as hazardous installations. Work in these facilities is complex, confined and associated with a wide range of risks. The continuous operation is secured by various shift work patterns. The objective of this study was to evaluate how offshore drilling workers perceived shift work at high seas and its impacts on their life and working conditions. The main features of the studied offshore shift work schedules are: long time on board (14 to 28 days), extended shifts (12 hours or more per day), slow rotation (7 to 14 days in the same shift), long sequence of days on the night shift (7 to 14 days in a row) and the extra-long extended journey (18 hours) on shift change and landing days. Interviews revealed a wide range of stressors caused by the offshore shift work, as well as difficulties to conciliate work with family life. It was observed that changes of the family model, leading to role conflicts and social isolation, work in a hazardous environment, perceiving poor sleep when working at night shifts and the imbalance between the expected and actual rewards are the major stressors for the offshore drilling workers.     

The hrpB and hrpG regulatory genes of Ralstonia solanacearum are required for different stages of the tomato root infection process

hrp genes, encoding type III secretion machinery, have been shown to be key determinants for pathogenicity in the vascular phytopathogenic bacterium Ralstonia solanacearum GMI1000. Here, we show phenotypes of R. solanacearum mutant strains disrupted in the prhJ, hrpG, or hrpB regulatory genes with respect to root infection and vascular colonization in tomato plants. Tests of bacterial colonization and enumeration in tomato plants, together with microscopic observations of tomato root sections, revealed that these strains display different phenotypes in planta. The phenotype of a prhJ mutant resembles that of the wild-type strain. An hrpB mutant shows reduced infection, colonization, and multiplication ability in planta, and induces a defense reaction similar to a vascular hypersensitive response at one protoxylem pole of invaded plants. In contrast, the hrpG mutant exhibited a wild-type level of infection at secondary root axils, but the ability of the infecting bacteria to penetrate into the vascular cylinder was significantly impaired. This indicates that bacterial multiplication at root infection sites and transit through the endodermis constitute critical stages in the infection process, in which hrpB and hrpG genes are involved. Moreover, our results suggest that the hrpG gene might control, in addition to hrp genes, other functions required for vascular colonization.     

Effect of modification of histidine residues on organization of the pigment--protein complexes of chromatium minutissimum

The effect of diethyl pyrocarbonate on chromatophores and isolated pigment--protein complexes of Chromatium minutissimum was studied. It is shown that modification of histidine residues results in the destruction of the core antenna LHI (B880) and in a spectral shift from 850 to 830 nm in the peripheral antenna LHII (B800-850). In the purple sulfur bacterium Chromatium minutissimum the pigment--protein complexes B800-B850 (peripheral antenna, LHII) and B880 (core antenna, LHI) collect and transmit the absorbed light energy to the reaction centers. The composition of pigments and proteins as well as primary structure of the majority of polypeptides in both types of complexes from various photosynthetic bacteria have been determined.     

In vitro regeneration from leaf explants of Neoregelia cruenta (R. Graham) L.B. Smith,an endemic bromeliad from Eastern Brazil

An efficient plant regeneration system was developed for the induction of direct shoot formation from leaves derived from seedlings of Neoregelia cruenta, an endemic Bromeliaceae of Eastern Brazil. Shoot differentiation occurred directly from the leaf bases. In vitro responses were influenced by seedling age and growth regulator combinations. Highest regeneration rates were obtained from explants excised from 7-week-old seedlings cultured in the presence of 22 μM BA and 2.5 μM NAA. Shoot conversion to whole plants was most effective in shoots formed in response to 4.4 or 8.8 μM BA combined with 2.5 μM NAA. This revised version was published online in June 2006 with corrections to the Cover Date.