HM Protein Research Articles

Supplement intake variation, weight, and body condition change in yearling heifers grazing late-summer dryland pastures with Rumax BoviBox vs. Rumax BoviBox HM protein supplements.

Supplement intake variation, weight, and body condition change in yearling heifers grazing late-summer dryland pastures with Rumax BoviBox vs. Rumax BoviBox HM protein supplements.

285 Supplement intake variation, weight, and body condition change in yearling heifers grazing late-summer dryland pastures with Rumax BoviBox versus Rumax BoviBox HM protein supplements

Abstract The objectives of this study were to evaluate Rumax BoviBox versus Rumax BoviBox HM protein supplements on supplement intake behavior, body weight (BW), and body condition score (BCS) change of yearling heifers grazing dryland pastures during late summer. Fifty-nine yearling commercial Angus heifers (428 kg) were stratified by BW and randomly assigned to one of two supplementation treatments: 1) free-choice access to Rumax BoviBox protein block supplement (30% CP, 23% salt; n = 29); and 2) free-choice access to Rumax BoviBox HM high magnesium protein block supplement (28.7% CP, 23% salt; n = 30). Individual supplement intake, time spent at the feeder, and intake variation were measured throughout the study. On d 0, 42, and 84 heifers were weighed and assigned a BCS following a 16-h shrink. Additionally, forage was sampled every 14 d throughout the study. Supplement intake (kg ∙ d-1) displayed a treatment × period interaction (P < 0.01). However, within period, treatment differences were not observed with intakes averaging 0.15 and 0.34 kg ∙ day-1 for d 0 – 42 and 42 - 84, respectively. Heifers spent more time at the feeder in period 2 than in period 1 (P < 0.01), averaging 7.67 vs 4.00 min per day, respectively. Supplement intake rate (g ∙ min-1) also displayed a treatment effect (P < 0.01) indicating that heifers in the Rumax BoviBox treatment had lower intake rate compared to Rumax BoviBox HM supplemented heifers. In conclusion, there were only minor differences in intake behavior and animal performance with the Rumax BoviBox and Rumax BoviBox HM supplement treatments. However, supplement intake increased and variation in intake decreased with declining forage quality and quantity.

SHM1: a multicopy suppressor of a temperature-sensitive null mutation in the HMG1-like abf2 gene.

HM, an HMG1-like mitochondrial DNA-binding protein, is required for maintenance of the yeast mitochondrial genome when cells are grown in glucose. To better understand the role of HM in mitochondria, we have isolated several multicopy suppressors of the temperature-sensitive defect associated with an abf2 null mutation (lacking HM protein). One of these suppressors, SHM1, has been characterized at the molecular level and is described herein. SHM1 encodes a protein (SHM1p) that shares sequence similarity to a family of mitochondrial carrier proteins. On glycerol medium, where mitochondrial function is required for growth, shm1 deletion mutants are able to grow whereas shm1 abf2 double mutants are severely inhibited. These results suggest the SHM1p plays an accessory role to HM in the mitochondrion.

187 METABOLIC AND ENERGY BALANCE IN SMALL (SGA) AND APPROPRIATE (AGA) FOR GESTATIONAL AGE VERY LOW BIRTH WEIGHT INFANTS FED FORTIFIED HUMAN MILK (HM)

Top of pageAbstract In litterature, there are discrepancies about nutrient and energy metabolism in SGA premature infants; that could be related to differences in type of intrauterine growth retardation. This study compares results of anthropometric data, 3-day nutritional balance and indirect calorimetry measurements performed in 8 AGA and 8 symmetrically growth retardated infants, at the same post-natal age. Infants were fed pooled HM protein and energy supplemented (HM fortifier: Eoprotin®, Milupa). Volume of milk intake, amounts of nitrogen and energy intake were similar in both groups. There was no significant difference in protein and energy absorption, but SGA infants tended to present a better fat absorption, likely because they were 3 weeks older. Weight gain and it's composition were similar in both groups, with approximately 20% of fat (non-protein energy deposition). In conclusion, there was no significant difference in response to diet between AGA and SGA VLBW infants. Nutritional needs seem to be similar in AGA and SGA infants, as long as growth retardation is syrnmetrical. This may be different when asymmetrically growth retardated infants are concerned.

The mitochondrial histone HM: An evolutionary link between bacterial HU and nuclear HMG1 proteins

The mitochondrial histone HM is a very abundant protein in yeast mitochondria that wraps DNA and activates transcription in vitro and is required within the cell for proper maintenance of the mitochondrial chromosome. HM and the bacterial histone-like protein HU have similar activities in vitro and can substitute for each other in E coli cells and in yeast mitochondria. HM also appears to be functionally homologous to nuclear HMG1 proteins, with which it shares a high degree of sequence homology. We report here the isolation of extragenic suppressors of the yeast HM mutant temperature-sensitive phenotype. We also examined the effects of the lack of HM protein and of respiration deficiency on yeast cells mutant for the NHP6 proteins, the putative yeast nuclear HMG1 homologues.

Functional complementarity between the HMG1-like yeast mitochondrial histone HM and the bacterial histone-like protein HU

The mitochondrial histone HM is the major DNA-binding protein in mitochondria and is necessary for maintenance of the mitochondrial genome in the yeast Saccharomyces cerevisiae during growth on fermentable sugars. HM and the Escherichia coli histone-like protein HU have similar activities in vitro, including DNA supercoiling, but share no sequence similarity. We show that HU can functionally complement the respiration deficiency associated with yeast strains lacking HM. Conversely, phenotypes of E. coli cells lacking HU protein, including nucleoid loss and a filamentous cell morphology, were alleviated by expression of HM in these cells. The HU protein of bacteria and the HM protein of mitochondria are therefore functionally complementary in vivo. Functional similarities among HM, HU, and the nuclear HMG1 proteins are implicated and discussed.

Protein Supplementation of Human Milk for the Nutrition of VLBW-Infants: Human milk protein vs. meat protein hydrolysate

In 25 very low birth weight infants appropriate for gestational age the influences of different human milk (HM) preparations on weight gain, gross indices of nitrogen metabolism and energy balance were studied during the second month of postnatal life. HM was fortified either by HM-protein (HMP) or by an enzymatic meat protein hydrolysate (PH) to protein concentrations between 1.5 and 1.7 g/100 ml. The caloric densities of both HM preparations were similar between 62 and 68 kcal/100 ml. There were no differences in weight gain (MM + HMP: 18.6 +/- 3.4 g/kg/day; HM + PH: 16.5 +/- 4.1 g/kg/day), nitrogen retention (HM + HMP: 31.5 +/- 3.1 mmol/kg/day; HM + PH: 30.0 +/- 3.2 mmol/kg/day), and the preprandial estimated essential amino acid profiles between the both feeding groups. In contrast the serum concentrations of alpha-amino-nitrogen 60 minutes postprandially were elevated in the infants fed HM + PH in comparison to the infants fed HM + HMP. This high postprandial amino acid concentrations in serum in the group fed HM + PH were accompanied by increased bile acids concentrations in serum, higher renal amino acid excretion and increased fecal fat losses. The results suggest that due to the more rapid intestinal absorption of amino acids from PH than from HMP the concentrations of amino acids increase postprandially which results in a detectable increase of the newborn cholestasis in these infants. Nevertheless, the scale of these metabolic responses to feeding protein hydrolysates is small and without detectable influences on nitrogen retention or weight gain.

Antibody response to defined domains on enterobacterial outer membrane proteins in healthy persons and patients with bacteraemia

Monoclonal antibody (MAb)-based competitive enzyme immunoassays (cELISAs) were elaborated to measure antibodies against MAb-defined domains on three different enterobacterial outer membrane (OM) proteins in sera from healthy individuals (n = 30) and in paired serum samples from patients (n = 45) with bacteraemia caused by enterobacteria or by various nonenteric bacteria (n = 15). The MAb-defined domains were Hm I and Hm II on the heat-modifiable (Hm) protein, PALp I and PALp II on the peptidoglycan-associated lipoprotein (PALp), and BLp I on Braun's lipoprotein (BLp). All MAbs have shown broad cross-reactivity with and specificity for enterobacteria. Sera from healthy individuals and from patients with infections caused by nonenteric bacteria contained low levels of MAb-blocking antibodies. Bacteraemia caused by enterobacteria resulted in generation of antibodies against the MAb-defined domains in many of the patients. Thus, 40% and 69% showed a positive BLp I cELISA with the first and second serum samples, respectively. Of the second serum samples, 20-38% showed positive Hm and PALp cELISAs. The BLp I cELISA showed higher diagnostic sensitivity than the previously described indirect ELISA for IgG antibodies against E. coli 055 OM protein antigens. Assays using the MAbs as competitors showed that the patients bacteraemic with enterobacteria, also generated antibodies against other domains on the OM proteins. The cELISAs may be useful in the diagnosis and management of patients with serious infections caused by enterobacteria. In this regard, the BLp I cELISA showed the most promising results.

Monoclonal antibodies against three different enterobacterial outer membrane proteins. Characterization, cross-reactivity, and binding to bacteria.

BALB/c mice were immunized with whole-cells of Escherichia coli 055:B5 or Proteus mirabilis NCTC 60 to produce broadly cross-reacting monoclonal antibodies (MAbs) against outer membrane (OM) proteins. A total of 10 anti-OM MAbs of the IgG class were selected. These included 5 MAbs against the heat-modifiable (Hm) protein, 3 against the peptidoglycan-associated lipoprotein (PALp), and 2 against Braun's lipoprotein (BLp). Based on competition ELISA, the MAbs defined 2 Hm protein binding sites (Hm I and Hm II), 2 PALp sites (PALp I and PALp II), and one BLp site (BLp I). The MAbs showed broad cross-reactivity against 74 strains of 10 different genera of the Enterobacteriaceae. Non-cross-reacting enteric bacilli occurred only among bacteria of the genera Salmonella, Proteus, and Providentia. The results revealed that Proteus and Providentia strains differed from other enteric bacilli with regard to BLp synthesis or specificity. A panel of 30 non-enteric Gram-negative bacteria did not cross-react. Testing of MAb binding to bacteria showed that a part of the BLp I, PALp I, and PALp II sites was immunoaccessible in intact homologous bacteria, and that the Hm I and Hm II epitopes were inaccessible. The MAbs should facilitate studies of structure and immunobiological function of enterobacterial OM proteins and should have a potential as immunodiagnostic reagents.

Increased urinary excretion of inorganic sulfate in premature infants fed bovine milk protein

We report measurements of urinary inorganic sulfate (iSO4) in 38 very low birth weight (VLBW) premature infants receiving various protein intakes in the first 2 months of life. The primary source of urinary iSO4 is the metabolism of amino acids containing sulfur (methionine, cysteine, taurine). It was hypothesized that urinary iSO4 excretion would be increased in VLBW infants fed the relatively high concentrations of protein in mother's own milk (HM), mother's own milk fortified with 0.85 gm/dl bovine whey (fortified HM), and a special formula for premature infants (Similac Special Care, 20 cal/oz), and that urinary iSO4 excretion would correlate with calcium excretion. VLBW premature infants fed HM (protein intake 3.3 gm/kg day) excreted very small amounts of urinary iSO4 compared with infants fed fortified HM (4.5 gm/kg/day protein), Similac SC (2.9 gm/kg/day protein), or Similac (2.7 gm/kg/day protein), all three of which contain bovine whey. Unlike the case in adults, there was no correlation between either total protein intake and urinary calcium excretion or urinary iSO4 excretion. There was, however, a significant correlation between methionine intake and urinary iSO4 excretion (r = 0.48). We speculate that increased urinary iSO4 excretion is indicative of an overload of sulfur-containing amino acids, namely methionine, present in bovine whey protein. The data also support the ability of premature infants to catabolize relatively large quantities of sulfur-containing amino acids after 2 weeks of age.

Yeast may not contain histone H1: the only known 'histone H1-like' protein in Saccharomyces cerevisiae is a mitochondrial protein.

It is likely that histone H1 is involved in the condensation of chromatin in eukaryotes. However, both the presence of histone H1 in yeast and the extent of yeast chromatin condensation are controversial. A 20 kD protein copurifies with yeast chromatin and was shown by other investigators to have characteristics of histone H1 protein. In an attempt to obtain a positive identification of the 20 kD protein, we purified the protein to homogeneity and raised antibodies against it. We show here by immunofluorescence that the 20 kD protein does not localize to the nucleus but to cytoplasmic particles resembling mitochondria. Furthermore, we show by Western-blot analysis that anti-20 kD protein antibodies react to protein isolated from purified mitochondria. Finally, we present evidence based on size, charge, amino acid composition and immunological cross reactivity to suggest that the yeast 20 kD protein is likely to be the mitochondrial DNA-binding HM protein. This leaves no candidate for histone H1 in yeast.