Maternal nutritional restriction during late gestation impairs development of the reproductive organs in both male and female lambs.

Maternal nutritional restrictions during late gestation could lead to fetal hypoglycemia. Glucose levels in the fetal sheep regulate circulating insulin-like growth factor 1 (IGF1) levels, which stimulate cell proliferation and differentiation of reproductive organs after binding to its own receptor or estrogen receptors. The objective of this study was to determine the effects of subnutrition of ewes during the last trimester of gestation on the serum glucose/IGF1 levels and development of reproductive organs in their lambs. Pregnant ewes carrying singletons were randomly assigned to restricted (R ewes, n = 8) or control (C ewes, n = 8) groups (4 lambs of each gender/group) and fed with 50% or 100% of metabolic energy requirements from ∼100 days of gestation to term (∼147 days), respectively. Blood samples from lambs were taken on the first day after born and once at week for serum glucose and IGF1 determination. Lambs were euthanatized at 2 months of age, reproductive organs were weighted and tissue samples were collected from them for histology and to measure mRNA expression of IGF1 and its receptor (IGF1R) by qRT-PCR. Pre-partum glucose levels in R ewes were significantly lower compared to C ewes (p < .05). Compared to lambs born from C ewes, lambs born from R ewes showed lower serum levels of glucose and IGF1 during the first week of age (p < .05). At 2 month of age, these lambs had significant lower uterine and testicular weight and lower ovarian, uterine and testicular mRNA expressions of IGF1 and its receptor (p < .05). Histological findings showed that diameter of secondary and tertiary follicles in ovaries and number of endometrial glands in uterus of females, or number of Sertoli cells and seminiferous tubules and diameter, perimeter and tubular area in testicles of males were significantly lower in lambs born from R ewes compared to the respective organs of lambs born from the C ewes (p < .05). In conclusion, these results demonstrate that maternal subnutrition during late gestation affects IGF1 levels during fetal life and impairs reproductive development in the neonatal lamb, which could have permanent negative consequences in the future reproductive performance of the offspring.

Comparison of two cysteine endopeptidases from Pseudananas macrodontes (Morr.) Harms (Bromeliaceae).

The properties of two cysteine peptidases (macrodontain I and II) isolated from fruits of Pseudananas macrodontes have been compared. The enzymes showed optimum pH ranges near neutrality and were inhibited by E-64 and other cysteine peptidase inhibitors. Molecular masses were 23459 and 23703 kDa, the isoelectric points were 6.1 and 5.9, and the Km values were 13.4 and 8.9 microM (Bz-Phe-Val-Arg-AMC) for macrodontain I and II, respectively. N-alpha-CBZ-L-amino acid p-nitrophenyl esters were tested for both enzymes. The N-terminal sequences of both proteases differed slightly and showed high sequence similarity to other pineapple stem-derived cysteine endopeptidases.

Properties of a milk clotting protease isolated from fruits of Bromelia balansae Mez.

Unripe fruit extracts of Bromelia balansae Mez (Bromeliaceae), whose principal endopeptidase is balansain I (isolated for anion exchange chromatography: pI = 5.45, molecular weight = 23192), exhibit a pH profile with a maximum activity around pH 9.0 and are inhibited only by cysteine peptidases inhibitors. The alanine and glutamine derivatives of N-alpha-carbobenzoxy-L-amino acid p-nitrophenyl esters were strongly preferred by the enzyme. Enzymatic hydrolysis of milk and soy proteins yield characteristic patterns at pH 9.0. The N-terminal sequence showed a very high homology (85-90%) with other known Bromeliaceae endopeptidases.

Purification of balansain I, an endopeptidase from unripe fruits of Bromelia balansae Mez (Bromeliaceae).

A new plant endopeptidase was obtained from unripe fruits of Bromelia balansae Mez (Bromeliaceae). Crude extracts were partially purified by ethanol fractionation. This preparation (redissolved ethanol precipitate, REP) showed maximum activity at pH 8.8-9.2, was very stable even at high ionic strength values (no appreciable decrease in proteolytic activity could be detected after 24 h in 1 M sodium chloride solution at 37 degrees C), and exhibited high thermal stability (inactivation required heating for 60 min at 75 degrees C). Anion exchange chromatography allowed the isolation of a fraction purified to mass spectroscopy, SDS-PAGE, and IEF homogeneity, named balansain I, with pI = 5.45 and molecular mass = 23192 (mass spectrometry). The purification factor is low (2.9-fold), but the yield is high (48.3%), a common occurrence in plant organs with high proteolytic activity, where proteases represent the bulk of protein content of crude extracts. Balansain I exhibits a similar but narrower pH profile than that obtained for REP, with a maximum pH value approximately 9.0 and was inhibited by E-64 and other cysteine peptidases inhibitors but not affected by inhibitors of the other catalytic types of peptidases. The alanine and glutamine derivatives of N-alpha-carbobenzoxy-L-amino acid p-nitrophenyl esters was strongly preferred by the enzyme. The N-terminal sequence of balansain I showed a very high homology (85-90%) with other known Bromeliaceae endopeptidases.

Sialic acid measurement by a modified Aminoff method: a time-saving reduction in 2-thiobarbituric acid concentration.

Our results show that if the 2-thiobarbituric acid concentration is decreased, its co-precipitation with the chromophore is diminished. Subsequent running of this reaction mixture by high-performance liquid chromatography still allows measurement of Neu-5-Ac in the picomole order, with a substantial time and reactive saving, as compared with the original assay.