[Analysis of Lymphocyte Subsets in Peripheral Blood of Patients with Aplastic Anemia or Hypoplastic Myelodysplastic Syndrome]

OBJECTIVE

To explore the ratio of lymphocyte subsets in peripheral blood of patients with aplastic anemia (AA) and patients with hypoplastic myelodysplastic syndrome (hypo-MDS) patients and to evaluate their significance.

METHODS

The clinical data of 181 cases of AA and 111 cases of hypo-MDS from January 2008 to December 2014 were collected from Blood Diseases Hospital of Chinese academy of medical sciences, and then the differences of lymphocyte subsets and its effect in 2 groups were analyzed.

RESULTS

CD4⁺/CD8⁺ ratio, proportion of CD3⁺ cells and its subsets CD3⁺CD4⁺/CD3⁺CD8⁺ cells in hypo-MDS group were not significant different from AA group (P>0.05). the proportion of CD3^-CD16/CD56⁺ NK cells and CD3⁺CD57⁺T-LGL cells in hypo-MDS group was significantly higher than that in AA group (P<0.05, P<0.01), but CD19⁺ B lymphocyte percentage in hypo-MDS patients was lower than that in AA patients (P<0.05). After dividing group according to CD4⁺/CD8⁺ ratio, the ratios of CD3⁺ CD16/CD56⁺ NK cells and CD3⁺/CD57⁺ T-LGL cells were higher only in normal CD4⁺/CD8⁺ ratio group of hypo-MDS patients than those in AA patients, while the ratio of B lymphocytes was significant different in inverted CD4⁺/CD8⁺ ratio group between hypo-MDS and AA patients. The CD19⁺ B lymphocyte ratio in hypo-MDS patients was significantly lower than that in AA patients (P<0.05). As well, the levels of erythrocytes and platelets in peripheral blood between hypo-MDS and AA patients only in normal CD4⁺/CD8⁺ ratio group were significantly different, while the significant difference of WBC count and reticulocyte ratio were observed in high CD4⁺/CD8⁺ ratio and non-inverted CD4⁺/CD8⁺ ratio groups, respectively; the significant difference of bone marrow blast ratio and muture monocyte ratio was found in high CD4⁺/CD8⁺ ratio group.

CONCLUSION

The changes of lymphocyte subsets can be used as an reference indicator for differential diagnosis of hypo-MDS and AA. The comparative analysis of patients with these 2 kinds of diseases after dividing into subgroups according to ratio of CD4⁺/CD8⁺ cells is beneficial to differentiat diagnosis.

In vivo studies of the anti-tumor effects of a human prolactin antagonist, hPRL-G129R

Previously we demonstrated that a mutated human prolactin (hPRL) with a single amino acid substitution at position 129 (hPRL-G129R) was able to inhibit human breast cancer cell proliferation via the induction of apoptosis. In this study, we report the in vivo anti-tumor effects of hPRL-G129R in nude mice bearing human breast cancer xenografts (T-47D and MCF-7). In an effort to prolong the half-life of the proteins, hPRL or hPRL-G129R were formulated with either growth factor reduced Matrigel or into slow-releasing pellets (custom made 5 mg/5 day release). Initially, nude mice inoculated (s.c.) with T-47D human breast cancer cells were treated with either hPRL or hPRL-G129R formulated with Matrigel. At the end of the 7-week study, it was found that hPRL significantly stimulated the in vivo growth of T-47D xenografts (mean tumor volume, 202 +/- 62 mm(3) as compared to 124 +/- 31 mm(3) in control mice), whereas hPRL-G129R inhibited the tumor growth (mean tumor volume, 79+/-32 mm3). The inhibitory effects of hPRL-G129R were further confirmed in a second experiment using nude mice bearing MCF-7 human breast cancer xenografts and treated with slow-releasing pellets containing hPRL-G129R. Based on these results, we believe that hPRL-G129R can be used to improve the outcome of human breast cancer treatment in the near future.

Fuzzy rules to predict degree of malignancy in brain glioma

The current pre-operative assessment of the degree of malignancy in brain glioma is based on magnetic resonance imaging (MRI) findings and clinical data. 280 cases were studied, of which 111 were high-grade malignancies and 169 were low-grade, so that regular and interpretable patterns of the relationships between glioma MRI features and the degree of malignancy could be acquired. However, as uncertainties in the data and missing values existed, a fuzzy rule extraction algorithm based on a fuzzy min-max neural network (FMMNN) was used. The performance of a multi-layer perceptron network (MLP) trained with the error back-propagation algorithm (BP), the decision tree algorithm ID3, nearest neighbour and the original fuzzy min-max neural network were also evaluated. The results showed that two fuzzy decision rules on only six features achieved an accuracy of 84.6% (89.9% for low-grade and 76.6% for high-grade cases). Investigations with the proposed algorithm revealed that age, mass effect, oedema, postcontrast enhancement, blood supply, calcification, haemorrhage and the signal intensity of the T1-weighted image were important diagnostic factors.

The regulatory role of DR4 in a spontaneous diabetes DQ8 transgenic model

MHC class II molecules are critical determinants of genetic susceptibility to human type 1 diabetes. In patients, the most common haplotype contains the DRA1*0101-DRB1*0401 (DR4) and DQA1*0301-DQB1*0302 (DQ8) loci. To assess directly the relative roles of HLA-DQ8 and DR4 for diabetes development in vivo, we generated C57BL/6 transgenic mice that lack endogenous mouse MHC class II molecules but express HLA-DQ8 and/or DR4. Neither HLA-DQ nor HLA-DR transgenic mice developed insulitis or spontaneous diabetes. However, when they were crossed to transgenic mice (C57BL/6) expressing the B7.1 costimulatory molecules on pancreatic beta cells that do not normally develop diabetes, T cells from these double transgenic mice were no longer tolerant to islet autoantigens. The majority of DQ8/RIP-B7 mice developed spontaneous diabetes, whereas only 25% of DR4/RIP-B7 mice did so. Interestingly, when DQ8 and DR4 were coexpressed (DQ8DR4/RIP-B7), only 23% of these mice developed diabetes, an incidence indistinguishable from the DR4/RIP-B7 mice. T cells from both DR4/RIP-B7 and DQ8DR4/RIP-B7 mice, unlike those from DQ8/RIP-B7 mice, exhibited a Th2-like phenotype. Thus, the expression of DR4 appeared to downregulate DQ8-restricted autoreactive T cells in DQ8DR4/RIP-B7 mice. Our data suggest that although both DQ8 and DR4 can promote spontaneous diabetes in mice with a non-autoimmune-prone genetic background, the diabetogenic effect of the DQ8 allele is much greater, whereas DR4 expression downregulates the diabetogenic effect of DQ8, perhaps by enhancing Th2-like immune responses.

Resveratrol-induced activation of p53 and apoptosis is mediated by extracellular-signal-regulated protein kinases and p38 kinase

Resveratrol, a phytoalexin found in grapes, berries, and peanuts, is one of the most promising agents for cancer prevention. Our previous study showed that the antitumor activity of resveratrol occurs through p53-mediated apoptosis. In this study, we have elucidated the potential signaling components underlying resveratrol-induced p53 activation and induction of apoptosis. We found that in a mouse JB6 epidermal cell line, resveratrol activated extracellular-signal-regulated protein kinases (ERKs), c-Jun NH2-terminal kinases (JNKs), and p38 kinase and induced serine 15 phosphorylation of p53. Stable expression of a dominant negative mutant of ERK2 or p38 kinase or their respective inhibitor, PD98059 or SB202190, repressed the phosphorylation of p53 at serine 15. In contrast, overexpression of a dominant negative mutant of JNKI had no effect on the phosphorylation. Most importantly, ERKs and p38 kinase formed a complex with p53 after treatment with resveratrol. Strikingly, resveratrol-activated ERKs and p38 kinase, but not JNKs, phosphorylated p53 at serine 15 in vitro. Furthermore, pretreatment of the cells with PD98059 or SB202190 or stable expression of a dominant negative mutant of ERK2 or p38 kinase impaired resveratrol-induced p53-dependent transcriptional activity and apoptosis, whereas constitutively active MEK1 increased the transcriptional activity of p53. These data strongly suggest that both ERKs and p38 kinase mediate resveratrol-induced activation of p53 and apoptosis through phosphorylation of p53 at serine 15.

[Chemical constituents from the root of Rubus chroosepalus]

AIM

To investigate the chemical constituents of Rubus chroosepalus Focke.

METHODS

The methanol extracts were suspended in H2O and then extracted with EtOAc. Column chromatography was used for separation and purification, while spectral analysis was used for identification.

RESULTS

Seven compounds were isolated and identified as 2 alpha, 3 beta-dihydroxy-urs-12, 19-dien-23, 28-oic acid (I), 2 alpha, 3 beta, 23-trihydroxy-urs-12,18-dien-28-oic acid (IIa), 2 alpha, 3 beta, 23-trihydroxy-urs-12,19-dien-28-oic acid (IIb), 2 alpha, 3 alpha-dihydroxy-urs-12,18-dien-28-oic acid (IIIa), 2 alpha, 3 alpha-dihydroxy-urs-12,19-dien-28-oic acid (IIIb), and the acetonide of IIIa and IIIb (IVa and IVb).

CONCLUSION

I was found to be a new pentacyclic triterpenoid acid.

Transactivation of AP-1 in AP-1-luciferase reporter transgenic mice by arsenite and arsenate

Arsenic is a recognized carcinogen, which acts as a tumor promoter rather than as an initiator. Signal transduction pathways leading to activation of AP-1 and mitogen-activated protein kinases are proposed to be responsible for the tumor promotion activity by arsenic. Induction of AP-1 DNA binding activity and c-jun and c-fos expression was reported to be only observed in cells responding to arsenite, but not to arsenate. However, in this study, we found that both arsenite and arsenate could induce transactivation of AP-1 in mouse epidermal JB6 AP-1-luciferase reporter stable transfectants, P+1-1. This induction of AP-1 activity by arsenic appears to be through activation of mitogen-activated protein kinases and protein kinase C because increased AP-1 activity by arsenite could be blocked by either treatment of cells with PD98059 or overexpression of dominant negative protein kinase Ca. Furthermore, both arsenite and arsenate could induce transactivation of AP-1 in AP-1-luciferase reporter transgenic mice.

Inhibition of oncogene STAT3 phosphorylation by a prolactin antagonist, hPRL-G129R, in T-47D human breast cancer cells

We have previously demonstrated that a hPRL antagonist (hPRL-G129R) was able to inhibit PRL induced breast cancer cell proliferation through induction of apoptosis. In the present study, we test the hypothesis that the inhibitory effect of hPRL-G129R in breast cancer cells occurs, at least in part, through the inhibition of oncogene STAT3 activation. We first demonstrated that STAT5 and STAT3 could be activated by either hGH or hPRL in T-47D breast cancer cells. Although the patterns of STAT5 activation by hGH and hPRL are similar, we observed a nearly 10-fold greater efficacy of hPRL in STAT3 activation as compared to that of hGH. More importantly, we have demonstrated that activation of STAT3 by hPRL could be inhibited by hPRL-G129R. Since T-47D cells coexpress GHR and PRLR, an attempt was made to dissect the molecular events mediated through hGHR or hPRLR using mouse L-cells expressing a single population of receptors (hGHR or hPRLR). To our surprise, only STAT5, not STAT3 phosphorylation was observed in these L-cells. In conclusion, our results suggest that: a) STAT3 is preferably activated through hPRLR in T-47D cells; b) hPRL-G129R is effective in inhibiting STAT3 phosphorylation; and c) the mechanism of STAT3 activation is different from that of STAT5.

Inhibition of arsenite-induced apoptosis and AP-1 activity by epigallocatechin-3-gallate and theaflavins

Arsenite-induced apoptosis appears to be important in its toxicity and its role in carcinogenesis. Green tea has been used as a traditional Chinese remedy for detoxification of arsenite-caused toxicity. In the present work, we found that tea polyphenols, EGCG and theaflavins, effectively blocked arsenite-induced apoptosis of JB6 cells and inhibited arsenite-induced AP-1 transcription activity and AP-1 DNA binding activity. EGCG and theaflavins potently inhibited arsenite-induced Erks activity, but not p38 kinase activity. PD 98059, an inhibitor of Erks, and DNM-JNK1 blocked arsenite-induced apoptosis, while SB202190, an inhibitor of p38 kinases, or DNM-p38 kinase did not. We conclude that Erks and JNKs may be involved in arsenite-induced apoptosis, and the inhibition of arsenite-induced apoptosis by EGCG and theaflavins may be mediated by a decreased phosphorylation of Erks and JNKs. Furthermore, these results provide a possible mechanism for the detoxification effect of tea on arsenite-induced toxicity.

Activation of PKC is required for arsenite-induced signal transduction

Trivalent arsenic (arsenite) is a human carcinogen. However, the molecular mechanism of arsenite-induced carcinogenesis is still not well understood. In this study, we found that arsenite induced translocation of PKCepsilon, PKCdelta, and PKCalpha from cytosol to membranes. Rottlerin, a selective inhibitor for PKCdelta, and safingol, a specific inhibitor for PKCalpha, both markedly inhibited arsenite-induced AP-1 activity. These inhibitory effects by rottlerin and safingol appeared to be dose dependent. Arsenite-induced phosphorylation of Erks was inhibited by rottlerin, while safingol inhibited arsenite-induced phosphorylation of JNKs and p38 kinases. Dominant negative mutant transfectant of PKCepsilon markedly blocked arsenite-induced AP-1 activity and the phosphorylation of Erks, JNKs, and p38 kinases. These data demonstrate that PKCdelta, PKCepsilon, and PKCalpha mediate arsenite-induced AP-1 activation in JB6 cells through different MAP kinase (Erks, JNKs, and p38 kinases) pathways.

Two new quinones from Spallerocarpus gracillis

Further phytochemical investigation of the aerial parts of Sphallerocarpus gracillis afforded two new quinones, named gracillisquinones A and B. Their structures were elucidated on the basis of spectral evidence including 2D NMR and X-ray techniques.

Liver and kidney growth hormone (GH) receptors are regulated differently in diabetic GH and GH antagonist transgenic mice

Elevated GH levels are frequently seen in poorly controlled type I diabetics and have been implicated in diabetic complications. Studies of GH and GH antagonist (GHA) transgenic mice with streptozotocin (STZ)-induced diabetes have revealed that GH has a permissive effect for diabetic nephropathy, and that expression of a GHA gene protected mice against diabetic kidney lesions. To investigate whether kidney GH receptor (GHR) and/or GH-binding protein may play a role in diabetic nephropathy, we evaluated GH-specific binding and messenger RNA levels for GHR/GH-binding protein in mouse livers and kidneys from bovine (b) GH or bGHA transgenic (Tg) mice and their nontransgenic (NTg) littermates with or without STZ-induced diabetes. We found that liver-specific GH binding is significantly higher in both bGH- and bGHA-Tg mice compared to that in their NTg controls. In contrast, kidney GH binding is significantly lower in bGH-Tg mice compared to that in NTg littermates. These results indicate that regulation of mouse GHR expression is tissue specific. STZ-induced diabetes decreased GH-specific binding in both liver and kidney of NTg and GHA-Tg mice, but not in bGH-Tg mice. The lowered GHR binding in diabetic NTg and GHA-Tg mice suggests the involvement of insulin in the regulation of GHR expression. The down-regulation of kidney GHR in GHA-Tg mice in combination with the presence of GHA may partially explain the protective mechanism of GHA against diabetic kidney lesions.

Co-expression of bovine growth hormone (GH) and human GH antagonist genes in transgenic mice

Bovine growth hormone (bGH) transgenic (Tg) mice have been shown to possess enhanced growth phenotypes and exhibit severe glomerulosclerosis. One amino acid substitution in GH, i.e. G119R in bGH or G120R in human (h) GH, results in GH antagonists (GHAs). GHA-Tg mice exhibit dwarf phenotypes and normal kidneys. In order to investigate the possibility of GHAs as pharmaceutical agents for the treatment of human diseases with excessive GH levels, we cross bred mice that express bGH with those that express hGHA. Double positive Tg mice were identified that express both genes although at different levels. Kidney histological studies revealed that the double positive Tg mice with high GHA/GH expression ratios possessed normal or near normal kidneys, whereas those with low GHA/GH ratios exhibited glomerulosclerosis similar to GH-Tg mice. Thus, co-expression of GH and GHA genes in vivo results in animal phenotypes and kidney histopathologies which are a reflection of the relative expression levels of each gene.

A growth hormone antagonist protects mice against streptozotocin induced glomerulosclerosis even in the presence of elevated levels of glucose and glycated hemoglobin

Transgenic mice expressing growth hormone genes have been shown to have kidney lesions resembling those found in human diabetic patients. However, transgenic mice expressing a growth hormone antagonist gene have normal kidneys. In this study, streptozotocin was used to induce diabetes in growth hormone or growth hormone antagonist transgenic mice and total glycated hemoglobin levels were determined. We found streptozotocin treatment resulted in a significant increase in glycated hemoglobin levels in these animals. Despite comparable levels of glycemia and glycated hemoglobin, severe glomerulosclerosis was found in diabetic and nondiabetic growth hormone transgenic mice; moderate glomerulosclerosis was seen in diabetic nontransgenic mice; and normal glomeruli were seen in diabetic and non-diabetic growth hormone antagonist transgenic mice as well as non-diabetic nontransgenic littermates. These results suggest that growth hormone is playing a role in diabetic nephropathy, and elevated levels of growth hormone can directly affect the kidneys independent of the levels of glucose and glycated hemoglobin.

Inhibition of diabetic nephropathy by a GH antagonist: a molecular analysis

Streptozotocin-treated C57B1/SJL mice developed glomerular hypertrophy and light microscopic lesions mimicking human diabetic glomerulosclerosis. In contrast, there were no glomerular hypertrophy and lesions in diabetic mice transgenic (TG) for a mutated growth hormone (bGH-G119K) that competes with native endogenous GH and results in dwarfism. We examined the molecular events underlying these findings. The non-transgenic (non-TG) diabetic mouse glomeruli had an increase in mRNA coding for alpha 1IV collagen, laminin B1, TGF-beta 1, 72 kDa collagenase, and TIMP-3. In contrast, glomerular type IV collagen and laminin B1 mRNA levels were normal in diabetic TG dwarf mice. However, the 72 kDa gelatinase, TIMP-3, and TGF-beta 1 mRNAs were elevated in the diabetic dwarfs. Type IV collagen and laminin accumulated in the glomeruli of diabetic non-TG, but not of diabetic dwarf mice, by immunofluorescence microscopy, confirming the mRNA data. GH binding protein mRNA levels were comparable in glomeruli from dwarf and non-TG mice, both diabetic and non-diabetic. We did not detect GH receptor mRNA in glomeruli. These data suggest that diabetic glomerulosclerosis is associated with an increase in type IV collagen and laminin synthesis, and that these changes do not occur in mice transgenic for bGH119K, a functional antagonist of GH. The increase of 72 kDa gelatinase, TIMP-3 and TGF-beta 1 mRNAs, independent of GH, suggested that these changes induced by hyperglycemia were not sufficient for the induction of glomerulosclerosis.

Amino acid residues in the third alpha-helix of growth hormone involved in growth promoting activity

The third amphiphilic alpha-helix of GH has been found to be an important motif in the biological activities of the molecule. To further characterize this growth-promoting domain, three bovine (b) GH analogs were designed: one contained a scrambled third amphiphilic alpha-helix (SAH); a second contained a scrambled hydrophilic region of the helix (SAP); and a third contained a scrambled hydrophobic region of the helix (SAB). Transgenic mice that expressed these mutated bGH genes were produced. SAH transgenic mice displayed a phenotype identical to nontransgenic littermates. SAB transgenic mice grew slightly larger than nontransgenic littermates but remained smaller than bGH transgenic mice. On the other hand, SAP transgenic mice exhibited a dwarf phenotype. We subsequently generated individual amino acid substitutions in the hydrophilic region of the helix. The results from the growth rates of corresponding transgenic mice demonstrated that most bGH analogs with individual amino acid substitution within the third alpha-helix retained wild type-like growth-promoting activity except those with alterations at positions 115, 119, 122, and 123. Together these residues are predicted to form a cleft in the helix. To further substantiate the importance of the cleft, we deleted Gly 119 (delta 119). This resulting bGH analog was inactive in vivo as well as in in vitro assays. These results indicated that the primary structure of the third alpha-helix is critical for GH's growth-promoting activity and Gly 119 is a crucial amino acid in this region. Three adjacent amino acids, Asp 115, Ala 122, and Leu 123, also contribute to the growth-enhancing ability of the molecule.

Effects of streptozotocin treatment in growth hormone (GH) and GH antagonist transgenic mice

To investigate GH's role in diabetic end organ damage, experimental diabetes was induced with streptozotocin (STZ) in bovine GH (bGH) or bGH antagonist transgenic mice and in their nontransgenic (NTG) litter mates. Body growth, blood glucose, serum insulin-like growth factor-I levels, liver GH receptor (GHR) binding, and kidney histology of these animals were evaluated. After administration of multiple low doses of STZ, 90% of the mice developed hyperglycemia. The diabetic animals, especially those expressing GH and GH antagonist transgenes, demonstrated retarded body growth and reduced insulin-like growth factor-I levels when compared with their nondiabetic litter mates. Kidney histology revealed severe glomerulosclerosis in diabetic and nondiabetic bGH transgenic mice. Diabetic NTG mice exhibited moderate kidney lesions. Diabetic bGH antagonist transgenic mice possessed normal glomeruli indistinguishable from those seen in nondiabetic NTG mice. GHR-binding assays revealed that liver GHR-binding sites were significantly reduced in diabetic NTG mice and transgenic dwarf mice when compared with their nondiabetic controls. Conversely, liver GHR-binding ability was significantly increased in bGH transgenic mice as compared with their NTG littermates and remained high during diabetes. It is concluded that transgenic mice that express a GH antagonist are protected from diabetes and or GH-induced nephropathy.

In vitro and in vivo studies of antagonistic effects of human growth hormone analogs

A bovine growth hormone (bGH) analog, bGH-G119R, has been shown to act as a functional antagonist of GH activity both in vitro and in vivo. In the present study, human (h) GH analogs with alterations in the third alpha-helix (G120A, G120R) and N terminus (I4A) were generated. These two regions have been reported to form binding site 2 in hGH, which is involved in in vitro dimerization of the GH receptor (GHR). The biological activities of these hGH analogs were tested in vitro by a radioreceptor assay and an assay to test the ability of the molecules to induce tyrosine phosphorylation of a 93-kDa protein in a human lymphocyte line, IM-9. The growth rate of transgenic mice that express different hGH analogs was used as an in vivo test of the activity of the molecules. The results demonstrated that G120R is a potent hGH antagonist both in vitro and in vivo. Transgenic mice expressing G120R demonstrated a growth-suppressed phenotype. However, I4A, which has been demonstrated to be a potent inhibitor of in vitro GHR dimerization, exhibited full growth promoting activity in transgenic mice. Thus, the ability of hGH analogs to induce GHR dimerization in vitro and the ability to promote growth in vivo are not directly correlated.

Organization and nucleotide sequence of the Bacillus subtilis diaminopimelate operon, a cluster of genes encoding the first three enzymes of diaminopimelate synthesis and dipicolinate synthase

The nucleotide sequence of a 7-kilobase segment of the Bacillus subtilis chromosome containing the entire coding regions for the enzymes catalyzing the first three steps of diaminopimelate synthesis as well as dipicolinate synthase has been determined. This group of functionally related genes, termed the dap operon, were arranged in the order orfY, orfX, asd, dapG, and dapA and were bracketed by potential rho-independent transcription terminators. The asd locus could complement the growth defect of Escherichia coli strains with an asd deletion. Disruption of the dapG locus led to the loss of aspartokinase I, with a phenotype similar to that of the temperature-sensitive dapG mutants described earlier (Roten, C. A. H., Brandt, C., and Karamata, D. (1991) J. Gen. Microbiol. 137, 951-962). The amino acid sequences of the deduced products of the asd, dapG, and dapA loci had high degrees of similarity with those of other aspartate semialdehyde dehydrogenases, aspartokinases, and dihydrodipicolinate synthases, respectively. Disruption of orfX had no effect on growth but caused a sporulation defect, characterized by low sporulation frequencies and heat-sensitive spores, which could be cured by supplementation with dipicolinate, similar to the phenotype of mutants defective in spoVF, the putative structural gene for dipicolinate synthase. Two other open reading frames, upstream of spoVF, encoded the 380 COOH-terminal residues of a protein homologous to mitochondrial processing proteases and an 85-residue polypeptide of unknown function. Transcription initiation sites associated with the orfY-orfX-asd-dapG-dapA gene cluster were mapped by primer extension. The results indicate that during vegetative growth, the three distal genes of the dap operon, asd, dapG, and dapA, are transcribed as a unit and orfY and orfX are not expressed, whereas at stage 5 of sporulation two separate transcripts are produced, one comprising all five genes, the other just the three distal genes of the operon.

Expression of truncated forms of the bovine growth hormone gene in cultured mouse cells

A synthetic oligonucleotide, 5'-d(CTAGT-CTAGACTAG)-3' which encodes translational termination codons in three reading frames, was inserted into either exon IV (pbGH-4A) or V (pbGH-5A) of the bovine growth hormone gene. The resultant plasmids, under the transcriptional regulation of the mouse metallothionein 1 promoter, were introduced into cultured mouse L-cells or rat GH3 cells. Compared to wild type bGH RNA, bGH-specific RNA transiently expressed from pBGH-5A or pBGH-4A DNA in mouse L-cells was similar or slightly smaller in size, respectively. Unexpectedly, bGH-4A RNA lacked exon IV sequences. Immunofluorescence and immunoprecipitation analyses revealed that wild type bGH was localized to the Golgi apparatus, while truncated hormones were confined to the cytoplasmic compartment of transfected cells. In addition, truncated hormones were shown to be secretion-defective albeit the bGH signal peptide was efficiently and precisely processed. Thus, structural alterations in the bGH gene can dramatically affect bGH precursor mRNA processing and hormone localization within cultured mouse fibroblast or rat pituitary cells.

Effects of a leucine analog on growth hormone processing and secretion by cultured cells

Bovine and rat growth hormones (bGH and rGH, respectively) possess signal peptides that direct the hormone to the secretory pathway and are proteolytically cleaved prior to secretion. Previous in vitro translation studies indicated that incorporation of the polar leucine analog beta-hydroxyleucine into de novo synthesized polypeptides inhibits signal peptide function. To test the effects of this analog on GH secretion by cultured animal cells, transfections of mouse L-cells with a bGH expression plasmid or metabolic labeling of endogenous rGH in anterior pituitary cells was performed in the absence or presence of beta-hydroxyleucine. Transient expression of bGH in mouse L-cells or endogenous expression of rGH in anterior pituitary cells resulted in an accumulation of GH in the culture medium. Treatment with beta-hydroxyleucine resulted in a block in secretion as evidenced by an accumulation of GHs within these cells. Amino-terminal sequencing of the intracellular form of the analog-substituted GHs demonstrated accurate signal peptide cleavage. In contrast, in vitro translations of bGH RNA performed in the presence of beta-hydroxyleucine and microsomal membranes resulted in the inhibition of signal peptide cleavage. The results suggest that beta-hydroxyleucine can uncouple signal peptide processing and protein secretion in cultured cells.

Identification of aecA mutations in Bacillus subtilis as nucleotide substitutions in the untranslated leader region of the aspartokinase II operon

Recent genetic mapping of the aspartokinase II (lysC) operon of Bacillus subtilis [M. Petricek. L. Rutberg & L. Hederstedt (1989) FEMS Microbiology Letters 61, 85-88; N.Y. Chen. J. J. Zhang & H. Paulus (1989) Journal of General Microbiology 135, 2931-2940] has shown its chromosomal location to be close to the aecA locus, the mutation of which leads to highly increased levels of aspartokinase II. In order to examine the relationship between lysC and aecA, we have cloned the control regions of the lysC operon from several independent aecA mutants and determined their nucleotide sequences. The nucleotide sequences of the aecA mutants differed from the wild-type sequence by the substitution of one or two nucleotides at two widely separated sites in the transcribed leader region of the lysC operon. To confirm that the observed nucleotide changes are indeed responsible for the AecA phenotype and not simply the reflection of sequence polymorphisms in different B. subtilis strains, we introduced the same nucleotide substitutions as those observed in the aecA strains into the leader region of the wild-type lysC operon by oligonucleotide-directed mutagenesis. The expression of the mutagenized genes was analysed after transcriptional or translational fusion to lacZ in a single-copy integration vector. The levels of beta-galactosidase were greatly elevated by the nucleotide substitutions, with similar increases observed in transcriptional and translational fusions. The high level of expression of beta-galactosidase in the lysC'-lac'Z strains with nucleotide substitutions corresponding to the aecA mutations was resistant to repression by L-lysine but was completely abolished by the inactivation of the lysC promoter.(ABSTRACT TRUNCATED AT 250 WORDS)

Mutations in the third alpha-helix of bovine growth hormone dramatically affect its intracellular distribution in vitro and growth enhancement in transgenic mice

To investigate the relationship between the secondary structure of the third alpha-helix (amino acids 109-126) of bovine growth hormone (bGH) and the biological activity of the molecule, proline or glycine residues have been used as substitutes for native amino acids at positions 114, 118, 121, and 126, respectively. Mutations at the positions 114, 118, and 121 resulted in a dramatic decrease in bGH secretion by transiently transfected mouse L cells whereas the substitution of glycine for glutamate at position 126 (bGH-E126G) did not affect secretion. Immunofluorescence staining revealed that those nonsecretory bGH mutations possessed a different intracellular location as compared with wild-type bGH or the mutated secretory forms of bGH. Similar results were seen in the distribution of these mutated bGH molecules in transfected rat GH-3 cells. Transgenic mice that express wild-type bGH or bGH-E126G grew to approximately 1.6 times the mass of nontransgenic littermates. Transgenic mice that express two nonsecretory forms of mutated bGHs were found to lack the enhanced mouse growth phenotype in spite of elevated levels of serum bGH. These results suggest that the secondary structure in the third alpha-helix of bGH may be important for efficient intracellular targeting in vitro and in growth promotion in transgenic mice.

Coping with FASB Statement No. 106--"Accounting for Post-retirement Benefits other than Pensions"

The Financial Accounting Standards Board has recently adopted Statement No. 106 providing accounting rules for nonpension postretirement benefits. This change presents a complex series of design, funding and tax issues that will forever change the way employers view the offering of postretirement benefits. Careful analysis of these issues within the specific context of each employer's human resources and financial strategy will be needed to select the proper course of action for dealing with this new accounting statement.

Comparison of the three aspartokinase isozymes in Bacillus subtilis Marburg and 168

The levels of two aspartokinase isozymes, a lysine-sensitive enzyme and an aspartokinase that is inhibited synergistically by lysine plus threonine, differ strikingly in different strains of Bacillus subtilis. In derivatives of B. subtilis 168 growing in minimal medium, the predominant isozyme is the lysine-sensitive aspartokinase. In B. subtilis ATCC 6051, the Marburg strain, the level of the lysine-sensitive aspartokinase is much lower during growth in minimal medium, and the major aspartokinase activity is the lysine-plus-threonine-sensitive isozyme. Molecular cloning and nucleotide sequence determination of the genes for the lysine-sensitive isozymes from the two B. subtilis strains and their upstream control regions showed these genes to be identical. Evidence that the lysine-sensitive aspartokinase, referred to as aspartokinase II, is distinct from the threonine-plus-lysine-sensitive aspartokinase comes from the observation that disruption of the aspartokinase II gene by recombinational insertion had no effect on the latter. Mutants were obtained from the aspartokinase II-negative strain that also lacked the threonine-plus-lysine-sensitive aspartokinase, which will be referred to as aspartokinase III. Aspartokinase II could be selectively restored to these mutants by transformation with plasmids carrying the aspartokinase II gene. Study of the growth properties of the various mutant strains showed that the loss of either aspartokinase II or aspartokinase III had no effect on growth in minimal medium but that the loss of both enzymes interfered with growth unless the medium was supplemented with the three major end products of the aspartate pathway. It appears, therefore, that aspartokinase I alone cannot provide adequate supplies of precursors for the synthesis of lysine, threonine, and methionine by exponentially growing cells.

Chromosomal location of the Bacillus subtilis aspartokinase II gene and nucleotide sequence of the adjacent genes homologous to uvrC and trx of Escherichia coli

The aspartokinase II (ask) operon of Bacillus subtilis consists of two in-phase overlapping genes that encode the two subunits of the lysine-sensitive isoenzyme of aspartokinase (ATP:L-aspartate 4-phosphotransferase, EC 2.7.2.4). Transduction mapping of the ask operon, inactivated by recombinational insertion of a cat marker, indicates a chromosomal location (about 253 degrees) between leuA and aroG. ask is thus remote from aecB, eliminating aecB as a possible locus for the structural gene of aspartokinase II, but close to aecA and uvrB. The nucleotide sequence of a 2 kb DNA fragment just upstream of the ask operon was determined and found to contain two open reading frames. The deduced amino acid sequence of the distal reading frame exhibits extensive homology with Escherichia coli thioredoxin and that of the proximal one, which overlaps with the ask promoter, is homologous to the deduced product of the E. coli uvrC gene. Insertional mutagenesis of the proximal open reading frame led to a mitomycin-sensitive phenotype, consistent with a role in DNA repair. In conjunction with the data of M. Petricek, L. Rutberg & L. Hederstedt [FEMS Microbiology Letters 61, 85-88] our results define the nucleotide sequence of an 8.8 kb segment of the B. subtilis chromosome near 253 degrees and the following order of genes: trx-uvrB-ask-orfX-sdhC-sdhA-sdhB-orfY++ +-gerE.

The combined use of insulin and sulfonylurea therapy in patients with non-insulin dependent diabetes mellitus

This study was initiated in order to evaluate the clinical efficacy of glipizide treatment in 18 patients with non-insulin dependent diabetes mellitus in poor glycemic control with insulin. Insulin dose was kept constant, and various facets of carbohydrate and lipid metabolism were evaluated before and from 4-6 months after the addition of glipizide. The results indicated that fasting and post-prandial glucose concentration were significantly (P less than 0.001) reduced following glipizide treatment, associated with a commensurate fall in glycosylated hemoglobin concentration. The average fall in fasting plasma glucose concentration in the total patient group approximated 60 mg/dl, and the mean decrement in 8 of the 18 patients who had a fall of more than 70 mg/dl in fasting glucose was 93 mg/dl. These results demonstrate that the addition of glipizide to the treatment program of patients with non-insulin dependent diabetes mellitus poorly controlled on insulin can lead to substantial clinical benefit.

Increased vascular contractile sensitivity to serotonin in spontaneously hypertensive rats is linked with increased turnover of phosphoinositide

This study was conducted to determine if increased vascular contractile sensitivity to serotonin in spontaneously hypertensive (SHR) rats is linked with increased phosphoinositide turnover. Aortic and mesenteric artery rings from SHR exhibited 6.2- and 5.0-fold greater contractile sensitivity to serotonin than the aortic and mesenteric artery rings from normotensive Wistar-Kyoto (WKY) rats. Serotonin-induced turnover of phosphoinositide was measured by quantifying the accumulation of [3H] inositol labeled inositol monophosphate (IP), inositol bisphosphate (IP2) and inositol trisphosphate (IP3). Serotonin (3, 30, 200 microM) induced significantly greater accumulation of IP in SHR (279%, 590%, 895%) than in WKY (24%, 127%, 328%) aortic rings. Similarly, 3, 30 and 200 microM serotonin induced significantly greater accumulation of IP2 (118%, 241%, 451%) and IP3 (90%, 100%, 247%) in SHR than the accumulation of IP2 (15%, 58%, 122%) and IP3 (19%, 27%, 73%) in WKY aortic rings. Based on these data it is suggested that the greater vascular sensitivity to serotonin in SHR, at least in part, is attributable to increased turnover of phosphoinositide.

Mechanism of expression of the overlapping genes of Bacillus subtilis aspartokinase II

The mechanism of expression of the overlapping genes that encode the alpha and beta subunits of aspartokinase II of Bacillus subtilis was studied by specific mutagenesis of the cloned coding sequence. Escherichia coli or B. subtilis VB31 (aspartokinase II-deficient), transformed with plasmids carrying either a deletion of the translation start site and about one-half of the coding region for the larger alpha subunit or a frameshift mutation early in the alpha subunit coding region, produced the smaller beta subunit in the absence of alpha subunit synthesis, indicating that beta subunit is not derived from alpha subunit and that its synthesis does not depend on the alpha subunit translation initiation site. The beta subunit translation start site was identified by oligonucleotide-directed mutagenesis of the putative translation start codon. Modification of the nucleotide sequence encoding methionine residue 247 of the alpha subunit from ATG to either TTA or AAT (but not GTG) abolished beta subunit synthesis but had no effect on the production of alpha subunit. This observation is consistent with peptide chain initiation by N-formylmethionine, which specifically requires an ATG or GTG sequence, and indicates that translation of the beta subunit starts at a site corresponding to Met247 of the alpha subunit. Initial studies on the function of the aspartokinase II subunits, using E. coli as a heterologous host, showed that beta subunit was not essential for the expression of the catalytic function of aspartokinase, measured in vitro and in vivo, nor for its allosteric regulation by L-lysine. Whether the beta subunit has a function specific to B. subtilis needs to be explored in a homologous expression system.

Nucleotide sequence of the overlapping genes for the subunits of Bacillus subtilis aspartokinase II and their control regions

The nucleotide sequence of a 2.9-kilobase Bacillus subtilis DNA fragment containing the entire coding region of aspartokinase II and adjacent chromosomal regions (Bondaryk, R. P., and Paulus, H. (1985a) J. Biol. Chem. 260, 585-591) has been determined. The results confirmed the earlier prediction that the two subunits of aspartokinase II, alpha and beta, are encoded by in-phase overlapping genes. The nucleotide sequence showed strong ribosome binding sites before the translation initiation codons of the alpha and beta subunits. Deletion of most of the coding region unique to the alpha subunit had no effect on the synthesis of the smaller beta subunit, demonstrating that the beta subunit is indeed the product of independent translation. The site of transcription initiation of the aspartokinase gene was found to be more than 300 nucleotides upstream from the translation start of the alpha subunit. The intervening region contained a short reading frame capable of encoding a 24-residue lysine-rich polypeptide, which overlaps a region of extensive dyad symmetry culminating in a rho-independent transcription terminator. This region may be an attenuator control element that regulates the expression of the aspartokinase gene in response to the availability of lysine, the end product of the pathway. The coding sequence of the aspartokinase II subunits was immediately followed by a rho-independent transcription terminator. This termination site has an unusual symmetry, which allows it also to serve as transcription terminator for a gene that converges on the aspartokinase II gene from the opposite direction, an interesting example of genetic economy. The deduced amino acid sequence of B. subtilis aspartokinase II was compared with the sequences of the three aspartokinases from Escherichia coli (Cassan, M., Parsot, C., Cohen, G. N., and Patte, J. C. (1986) J. Biol. Chem. 261, 1052-1057). Significant sequence similarities suggest a close evolutionary relationship between the four enzymes.

[Pattern recognition on the trace element spectrum in gastric cancer and peptic ulcer]

The trace element spectrum of gastric tissue and whole blood specimens from gastric cancer and peptic ulcer patients was recognized with pattern recognition technique in order to obtain the chemical information of gastric cancer. Thirty specimens were obtained from cancer patients in each of the 58 gastric tissues and 54 whole blood specimens. Five pathological types were divided into two groups: peptic ulcer and dysplasia as the ulcer group; well-differentiated, undifferentiated and mucinous carcinoma as the cancer group. The accuracy of recognizing the several spectra was 90%: nine trace element spectra (Cu, Zn, Ni, Co, Cr, Cd, Mn, Fe and Mg) for the tissue specimens from the cancer and ulcer groups; six (Cu, Zn, Mn, Co, Cr and Cd) for dysplasia and well-differentiated adenocarcinoma tissues; five (Cu, Ni, Cr, Cd and Fe) for the whole blood specimens from these two groups and six (Cu, Zn, Cr, Cd, Fe and Ni) for the whole blood specimens from dysplasia and peptic ulcer (including 10 normal individuals). The data were treated by non-linear mapping method and calculated by TRS-80 III type microcomputer.

Low-pressure airlift fermenter for single cell protein production: II. Continuous culture of pichia yeast

Experiments using Pichia yeast grown on n-paraffins have been conducted in laboratory 10-L airlift fermenters and in a 640-L module of commercial scale. Results confirmed the design concept of combining oxygen transfer and fermenter cooling with low-pressure air. However, in the absence of mass transport constraints, the build up of toxic factors in the fermenter appeared to be a major variable limiting cell productivity. Foaming in the large fermenter also presented a serious problem, which must be solved before low-pressure airlift fermenters become practical.

Fast atom bombardment and collisional activation mass spectrometry in the structural analysis of steroidal oligoglycosides

Fast atom bombardment (FAB) followed by collisional activation (CA) mass spectrometry was used for structural analysis of steroidal oligoglycosides, containing two to four sugar units. In the molecular ion region of the FAB mass spectra of these underivatized natural products, intense protonated molecular ions were observed. The collisional activation spectra of these mass selected ions yield more sequence information than FAB mass spectra and are not contaminated with interfering peaks originating from impurities or matrix.