Defined starter system including a bacteriocin producer for the enhancement of cheese flavour

Defined starter systems, consisting of bacteriocin-tolerant Lactococcus lactis subsp. lactis H6 alone or in combination with bacteriocin-sensitive L. lactis subsp. cremoris H1, and low amounts of a bacteriocin-producing culture, were developed and used for the manufacture of semi-hard cheese. Aminopeptidase activity and proteolysis were increased and acidification retarded in cheeses made from milk inoculated with lactococci and the bacteriocin-producing culture with respect to cheeses from milk inoculated with only lactococci. Cheeses made with a defined-strain starter system consisting of L. lactis subsp. lactis H6 and the bacteriocin-producing culture received the highest scores for flavour intensity and quality.     

Hormonal modulation of biosynthesis of prostatic specific antigen, prostate specific acid phosphatase and prostatic inhibin peptide.

Hormonal modulation of in vitro biosynthesis of three prostatic secretory proteins, prostate specific acid phosphatase (PSAP), prostate specific antigen (PSA) and prostatic inhibin peptide (PIP) by human benign hyperplasia (BPH) tissue was studied. LH and inhibins caused increase in the synthesis of all three proteins whereas FSH enhanced the synthesis of PIP and PSA only but decreased PSAP synthesis. Prolactin and thyroid releasing hormone decreased synthesis of PIP and PSAP. However, PSA synthesis was enhanced by TRH and was decreased by prolactin. Estradiol caused significant increase in PSA and PSAP but no discernible changes in PIP synthesis were noticed. Testosterone caused an increase in PIP, PSA and PSAP. These data indicate that biosynthesis of PIP, PSA and PSAP by BPH tissue is under multihormonal regulation.     

Antifertility effects in rats actively immunized with 80 kDa human semen glycoprotein.

A 80 kDa human sperm antigen has been identified using the serum of an infertile woman having circulating antisperm antibodies. The antigen was then purified to homogeneity by gel permeation chromatography using HPLC (protein PAK-125 column) system and on FPLC (superose-12 column) system. The antigen was found to be a glycoprotein. The antigen was mainly localized in the postacrosomal region of the human sperm, while it was localized in the head region of the rat sperm as demonstrated by immunofluorescent staining. The presence of this antigen was also demonstrated in the human prostate and endometrium and in the rat testis; epididymis and the prostate by immunocytochemical staining. The purified protein upon active immunization in female rats caused infertility in 100 percent animals. While in male rats it caused infertility in 90 percent animals. On morphometric analysis of testicular tissue it was observed that there was no significant change in spermatogonia and spermatocytes, but significant decrease in spermatids and sperm number as well as daily sperm production in the immunized male rats. The epididymal spermatozoa were markedly reduced in number and were largely found to be agglutinated. The results suggest that 80 kDa human sperm antigen appears to be a suitable candidate for immunocontraception both in male and female.     

DNA probes for detection of copper resistance genes in Xanthomonas campestris pv. vesicatoria.

The copper resistance (Cur) genes encoded on pXV10A, a 190-kb plasmid in Xanthomonas campestris pv. vesicatoria XV10, were isolated on a 44-kb cosmid clone designated pCuR1. Tn5 mutagenesis of pCuR1 indicated that a 4.0-kb region was required for copper resistance. Three restriction fragments located within the 4.0-kb region demonstrated high specificity for the Cur genes present in X. campestris pv. vesicatoria and will be useful in monitoring the presence of these genes in the environment.     

Acceleration of flavour formation in cheese by a bacteriocin-producing adjunct lactic culture

Bacteriocin-producing Enterococcus faecalis INIA 4 was used as adjunct lactic culture at inoculum levels ranging from 0.003% to 0.10% in the manufacture of semi-hard cheese. Cheese made from milk with 0.003% adjunct culture had the most pronounced proteolysis and developed a characteristic cheese flavour faster than the rest, reaching in 30.4 days the flavour intensity score of a 45-day control cheese made without adjunct culture.     

Terminal phase of cytokinesis in D-98S cells

The events leading to the completion of cytokinesis after the formation of the midbody and intercellular bridge in D-98S cells were studied with light and electron microscopy. Pairs of daughter cells corresponding to different stages of cytokineses, as determined previously form time lapse films, were selected from embedded monolayers for serial sectioning. Separation of daughter cells is preceded by the reduction in diameter of the intercellular bridge from 1-1.5 μm to approx. 0.2 μm. Two processes contribute to this reduction: (a) The intercellular bridge becomes gradually thinner after telophase; a progressive breakdown of midbody structures accompanies this change; and (b) the more significant contribution to reduction in bridge diameter occurs through the localized constriction of a segment of the intercellular bridge.. The microtubules within the constricted portion of the bridge are forced closer together, and some microtubules disappear as this narrowing progresses. The plasma membrane over the narrowed segments is thrown into a series of wavelike ripples. Separation of daughter cells is achieved through movements of the cells which stretch and break the diameter-reduced bridge. The midbody is discarded after separation and begins to deteriorate. Occasional pairs of daughter cells were found in which incomplete karyokineses resulted in their nuclei being connected by a strand of nuclear material traversing the bridge and midbody. Such cells do not complete cytokinesis but merge together several hours after telophase. This merging of daughter cells coincides with the nearly complete breakdown of the midbody.     

Secretion and degradation of parathormone as a function of intracellular maturation of hormone pools

The biosynthesis, processing, and secretion of parthormone and the effect of calcium on these processes were measured in dispersed porcine parthyroid cells incubated with [(35)S]methionine. Proparathormone was detected at 10 min, the earliest time measured, and was rapidly and apparently quantitatively converted to parathormone. The half-life of the prohomormone pool was 15 min. Secretion of parathormone was detected by 20 min. In pulse-chase experiments there was a period between 20 and 40 min during which the wave of newly-synthesized parathormone was secreted. After 40 min during little additional radioactive hormone was secreted, but dibutyryl cyclic AMP, an agent that can mobilize stored parathormone, when added to the incubation mixtures enhanced radioactive parathormone secretion but only after 60 min, although it increased net hormone secretion as determined by radioimmunoassay to the same extent at all times studied. When the ionized calcium concentration of the medium was lowered, more radioactive hormone was secreted at all times but the effect was greatest on that hormone that was synthesized less than 60 min previously ; however, net hormone secretion in contrast to radioactive hormone was enhanced equally at all intervals. These data could mean that the refractoriness to secretion of parathormone 40-60 min of age was related to maturation of secretory container preparatory to storage. Low calcium (0.5 mM) stimulated hormone secretion up to fivefold compared to high calcium (3.0 mM) but did not affect synthesis of parathormone or proparathormne or conversion of the latter to hormone. During processing at least 70 percent of the intracellular parathormone was lost, presumably through proteolysis and this degradation was greater at high calcium. These data have been interpreted in light of the concept that two secretable pools of parathormone exist within the parathyroid.