Recombination between NADC34-like and QYYZ-like strain of Porcine Reproductive and Respiratory Syndrome virus with high pathogenicity for piglets in China

Porcine reproductive and respiratory syndrome virus (PRRSV) is an important pathogen that causes huge economic losses to the swine industry worldwide. Here, a novel variant of PRRSV strain named TJnh2021 was isolated from nursery piglets with morbidity rate (75%) and mortality rate (40%) in Tianjin Province of China in 2021. Phylogenetic and molecular evolutionary analyses revealed that TJnh2021 was highly similar to NADC34-like (lineage1.5, isolated in North America in 2014) in the ORF1ab-ORF2 and ORF6-ORF7 coding regions, as well as to QYYZ-like (lineage3, isolated in China in 2010) in the ORF3-ORF5, suggestive of a natural recombination event. Recombination analyses revealed that recombination events occurred in two inter-lineage recombination events between lineages 1.5 and 3, and two breakpoints in ORF2 (nt12196) and ORF5(nt13628) (with reference to the VR-2332 strain). Animal experiments demonstrated that TJnh2021 caused mortality rates of 40% and exhibited higher pathogenicity in piglets compared to other lineage 1.5 strains reported in China. Taken altogether, NADC34-like PRRSV has undergone genetic exchange with Chinese local PRRSV strains and recombination might be responsible for the variations in pathogenicity and highlight the importance of surveillance of this lineage in China. This article is protected by copyright. All rights reserved.

Novel ORF5 deletion of NADC30-like porcine reproductive and respiratory syndrome viruses circulating in northern China from 2016 to 2018

North American porcine reproductive and respiratory syndrome virus (NA-PRRSV), especially NADC30-like PRRSV, has evolved and is prevalent in China. We collected 503 samples from pig breeding farms across 4 provinces in northern China from 2016 to 2018. The samples were screened by PCR testing with specific primers that could differentiate groups of NA-PRRSV; phylogenetic trees were constructed and analyzed. Overall, 175 of 503 (34.8%) samples were positive for NA-PRRSV. Dual (NADC30-like and highly pathogenic [HP]-PRRSV; NADC30-like and typical PRRSV; HP and typical PRRSV) and triple (NADC30-like, HP, and typical PRRSV) infections (92 of 175, 52.6%) were common in coinfections by NADC30-like and HP-PRRSV. Notably, 18 of 125 (14.4%) semen samples were positive for PRRSV, and 17 of the 18 positive semen samples contained NADC30-like PRRSV. Phylogenetic analysis based on GP5 amino acids revealed that the novel NADC30-like PRRSV with a unique single amino acid deletion at position 34 has become widespread and has evolved into a new subgroup.

Early infection of Streptococcus suis serotype 2 increases the virulence of highly pathogenic porcine reproductive and respiratory syndrome MLV-like virus in pigs

Modified-live virus (MLV) vaccines derived from highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) were wildly used in China, which resulted in the emergence of MLV-like strains in pigs. Previous studies demonstrated that secondary bacterial infection could enhance HP-PRRSV infection-mediated inflammatory responses, but it is unknown whether early bacterial infection could enhance the HP-PRRSV MLV-like infection-mediated pathological reaction. In this paper, to gain the evidence for infection of pigs with MLV-like strains in China, we firstly analyzed the genetic characterization of the HP-PRRSV MLV-like isolate (TJxq1701) and further evaluated whether the early Streptococcus suis infection synergizes HP-PRRSV MLV-like infection-mediated pathological reaction. Our results showed that the whole genome of TJxq1701 shared the highest homology with JXA1-P80 and a total of 16 amino acids residues unique to JXA1-P80 in ORF1a, ORF1b, GP2, GP3, GP4, and GP5 were found in the corresponding locations. The results of infection experiments in pigs revealed that TJxq1701 caused transitional fever, moderate respiratory clinical sign and microscopic lung lesions in piglets, but early infection with low virulence Streptococcus suis serotype 2 (SS2) exhibited seriously clinical signs, including high fever, anorexia, and respiratory distress, leading to 60% mortality within four weeks in comparison with alone infected group. Taken together, our findings reveal that early bacterial infection could enhance the HP-PRRSV MLV-like infection-mediated pathological reaction, which provide an important clue for understanding that streptococcus infection increases the pathogenicity of MLV-like virus and a new thought for prevention and control of PRRSV.

[Clinical application of robotic plat form in the treatment of early ovarian cancer]

Objectives: To evaluate the feasibility and safety of robotic system in early ovarian cancer surgery. Methods: The clinical data of 131 patients with early ovarian cancer undergoing surgical treatment from November 2014 to November 2015 were reviewed retrospectively. There were 27 cases of early ovarian cancer, of which 9 cases of robotic group, 10 cases of laparoscopic group, 8 cases of laparotomy group. Age, Body Mass Index (BMI), preoperative neoadjuvant chemotherapy, operating time, operating method, intraoperative blood loss, intraoperative and postoperative complications, pathological type, lymph node dissection, postoperative exhaust time and postoperative hospital stay of all the patients were analyzed. Results: In the robot group, the mean operating time was( 251.4±58.7) minutes, the intraoperative blood loss was (208.9±202.7) ml, and the number of the main abdominal and pelvic lymph nodes was 27.8±8.9. The mean postoperative hospital stay was (11.1±3.5) days, and the mean postoperative hospital stay was( 2.0±0.5) days. All the patients were followed up for 12-24 months. There was no differences were observed among the three groups for operating time, complications, the blood loss, the number of lymph nodes, the hospital stay and survival time (P≥0.05). Conclusion: A robotic approach for the early ovarian cancer is feasible and effective. Compared with traditional laparoscopic surgery and laparotomy, there is no significant difference in operative effect and tumor-free survival. The robotic approach provides a new method for surgical treatment of early ovarian cancer.

Effect of weaning age on cortisol release in piglets

The effect of weaning age on the adrenal cortex, which plays a vital role in the stress response, is currently unknown. Therefore, plasma adrenocorticotropic hormone (ACTH) and cortisol levels, weights and relative weights of adrenal glands, and steroidogenesis-related protein and enzyme expression levels in piglets weaned on different days were determined. Piglets weaned at 35 days had significantly lower ACTH levels than those weaned at 14 or 21 days, and cortisol levels of piglets weaned at 21, 28, and 35 days were significantly lower than those of piglets weaned on day 14. Adrenal gland weights of piglets weaned at 28 and 35 days and relative adrenal gland weights of piglets weaned at 35 days were significantly lower than those of piglets weaned at 14 days. However, no significant difference was detected in the expression of melanocortin-type 2 receptor mRNA, which is associated with weaning age. Steroidogenic acute-regulatory (StAR) mRNA and cholesterol side-chain cleavage cytochrome P450 mRNA expression levels in piglets weaned at 28 and 35 days were significantly lower than in those weaned at 14 or 21 days, and P450 11β mRNA expression levels in piglets weaned at 28 and 35 days were significantly lower than in those weaned at 14 days. Therefore, early-weaned piglets exhibited increased adrenal gland weights and StAR and steroidogenic enzyme expression, all of which contributed to high cortisol levels. The high plasma ACTH and cortisol levels in early-weaned piglets indicate that these animals would be greatly affected by stress.

Ontogenetic Expression of Lpin2 and Lpin3 Genes and Their Associations with Traits in Two Breeds of Chinese Fat-tailed Sheep

Lipins play dual function in lipid metabolism by serving as phosphatidate phosphatase and transcriptional co-regulators of gene expression. Mammalian lipin proteins consist of lipin1, lipin2, and lipin3 and are encoded by their respective genes Lpin1, Lpin2, and Lpin3. To date, most studies are concerned with Lpin1, only a few have addressed Lpin2 and Lpin3. Ontogenetic expression of Lpin2 and Lpin3 and their associations with traits would help to explore their molecular and physiological functions in sheep. In this study, 48 animals with an equal number of males and females each for both breeds of fat-tailed sheep such as Guangling Large Tailed (GLT) and Small Tailed Han (STH) were chosen to evaluate the ontogenetic expression of Lpin2 and Lpin3 from eight different tissues and months of age by quantitative real-time polymerase chain reaction (PCR). Associations between gene expression and slaughter and tail traits were also analyzed. The results showed that Lpin2 mRNA was highly expressed in perirenal and tail fats, and was also substantially expressed in liver, kidney, reproductive organs (testis and ovary), with the lowest levels in small intestine and femoral biceps. Lpin3 mRNA was prominently expressed in liver and small intestine, and was also expressed at high levels in kidney, perirenal and tail fats as well as reproductive organs (testis and ovary), with the lowest level in femoral biceps. Global expression of Lpin2 and Lpin3 in GLT both were significantly higher than those in STH. Spatiotemporal expression showed that the highest levels of Lpin2 expression occurred at 10 months of age in two breeds of sheep, with the lowest expression at 2 months of age in STH and at 8 months of age in GLT. The greatest levels of Lpin3 expression occurred at 4 months of age in STH and at 10 months of age in GLT, with the lowest expression at 12 months of age in STH and at 8 months of age in GLT. Breed and age significantly influenced the tissue expression patterns of Lpin2 and Lpin3, respectively, and sex significantly influenced the spatiotemporal expression patterns of Lpin3. Meanwhile, Lpin2 and Lpin3 mRNA expression both showed significant correlations with slaughter and tail traits, and the associations appear to be related with the ontogenetic expression as well as the potential functions of lipin2 and lipin3 in sheep.

Characterization of adrenal ACTH signaling pathway and steroidogenic enzymes in Erhualian and Pietrain pigs with different plasma cortisol levels

Our previous study demonstrated significant difference in the basal plasma cortisol levels between Erhualian (EHL) and Pietrain (PIE) pigs, implicating fundamental breed difference in adrenocortical function. The objectives of the present study were therefore to characterize the expression pattern of proteins involved in adrenal ACTH signaling and, including melanocortin type 2 receptor (MC2R), cAMP response element binding protein (CREB) and phosphorylated CREB (pCREB), steroidogenic acute regulatory protein (StAR), as well as that of the key enzymes involved in steroidogenesis in EHL and PIE pigs, in association with the plasma corticotrophin (ACTH) and cortisol levels. The plasma concentrations of the substrates for adrenal steroidogenesis, cholesterol and low-density lipoprotein (LDL) cholesterol, did not differ between breeds. Plasma concentration of ACTH and the adrenal contents of MC2R mRNA and protein were similar in two breeds of pigs, whereas the basal plasma concentrations of cortisol in EHL pigs were 1.5 folds higher than that in PIE pigs. The higher basal plasma cortisol levels in EHL pigs were found to be accompanied with the higher expression of ACTH post-receptor signaling components, cAMP, pCREB and StAR, as well as the higher expression of cholesterol side-chain cleavage cytochrome P450 (P450scc), 17alpha-hydroxylase cytochrome P450 (P450(17alpha)), 21-hydroxylase cytochrome P450 (P450c21) and 11beta-hydroxylase cytochrome P450 (P450(11beta)). These results indicated that the enhanced cAMP/PKA/pCREB-signaling system and augmented expression of StAR and steroidogenic enzymes are major attributes to the higher basal plasma cortisol concentrations in pigs.

Diminished expression of ACTH signaling proteins and steroidogenic limiting factors in adrenocortical cells isolated from halothane nn pigs

Previous studies demonstrated significantly lower plasma cortisol level in homozygous halothane-positive (Hal nn) pigs, as compared with homozygous halothane-negative (Hal NN) pigs. To determine whether such difference is attributed to the fundamental alterations in adrenocortical function, F1 offsprings from Pietrain (Hal nn)xErhualian (Hal NN) were intercrossed to produce F2 sibling pigs with segregated genotypes. Adrenocortical cells were isolated from the Hal nn and Hal NN F2 pigs, respectively, and cultured with or without ACTH challenge. Cortisol levels in culture medium, as well as the content of MC2R, cAMP, CREB, phosphorylated CREB (pCREB), StAR and P450scc in adrenocortical cell lysates, were determined. Cortisol, cAMP, StAR and P450scc levels were significantly lower in Hal nn adrenocortical cells under basal condition without ACTH challenge. ACTH significantly increased cortisol level in the medium and the protein content of MC2R, StAR, P450scc in adrenocortical cell lysates, regardless of genotypes. Total CREB protein content was not different between genotypes and treatments, whereas pCREB content exhibited significant effects of genotype and treatment, being higher in Hal NN than in Hal nn under basal condition and in response to ACTH challenge. These results indicate that the compromised cAMP/PKA/pCREB signaling pathway of ACTH and diminished expression of limiting factors in adrenocortical steroidogenesis (StAR and P450scc) may contribute to the significantly lower plasma cortisol levels in Hal nn pigs.

Statistical measures of DNA sequence dissimilarity under Markov chain models of base composition

In molecular biology, the issue of quantifying the similarity between two biological sequences is very important. Past research has shown that word-based search tools are computationally efficient and can find some new functional similarities or dissimilarities invisible to other algorithms like FASTA. Recently, under the independent model of base composition, Wu, Burke, and Davison (1997, Biometrics 53, 1431 1439) characterized a family of word-based dissimilarity measures that defined distance between two sequences by simultaneously comparing the frequencies of all subsequences of n adjacent letters (i.e., n-words) in the two sequences. Specifically, they introduced the use of Mahalanobis distance and standardized Euclidean distance into the study of DNA sequence dissimilarity. They showed that both distances had better sensitivity and selectivity than the commonly used Euclidean distance. The purpose of this article is to extend Mahalanobis and standardized Euclidean distances to Markov chain models of base composition. In addition, a new dissimilarity measure based on Kullback-Leibler discrepancy between frequencies of all n-words in the two sequences is introduced. Applications to real data demonstrate that Kullback-Leibler discrepancy gives a better performance than Euclidean distance. Moreover, under a Markov chain model of order kQ for base composition, where kQ is the estimated order based on the query sequence, standardized Euclidean distance performs very well. Under such a model, it performs as well as Mahalanobis distance and better than Kullback-Leibler discrepancy and Euclidean distance. Since standardized Euclidean distance is drastically faster to compute than Mahalanobis distance, in a usual workstation/PC computing environment, the use of standardized Euclidean distance under the Markov chain model of order kQ of base composition is generally recommended. However, if the user is very concerned with computational efficiency, then the use of Kullback-Leibler discrepancy, which can be computed as fast as Euclidean distance, is recommended. This can significantly enhance the current technology in comparing large datasets of DNA sequences.

[Does a sector resection of the breast cure nodal mastopathy?]

Results of the clinico-morphological investigation of 265 patients with localized mastopathy who were submitted to sectorial resection showed that in the margins of the operative wound there were morphological signs of mastopathy in 252 (95.1%) patients. The results obtained confirm the opinion that structural alterations of the tissues known to be the essential feature of fibroadenomatosis can not be local, they are of diffuse character. So, the sectorial resection performed for localized mastopathy can not be radical and is of no therapeutic significance. The indication to surgical intervention must be determined not so much by the necessary treatment as by the real risk of hypo-diagnosis of breast cancer. So, there is no need to fulfil the sectorial resection for localized mastopathy. It is enough to make operation of less volume (excision biopsy).

[How often is breast fibroadenomatosis asymptomatic?]

The results of clinico-morphological examinations of 386 women having no complains of discomfort in the mammary glands are presented. Methods of palpation, mammography and morphological investigation have detected fibroadenomatosis without subjective symptoms of the disease in 38%, 67% and 78% of the patients correspondingly. This variant of the disease is called asymptomatic since the woman can not notice it and so it is out of the field of attention of oncologists. High incidence of asymptomatic fibroadenomatosis requires a revision of the current assessment of it as a disease because it does not take into account a variant of the disease when the patient has no complains of painful indurations in the mammary glands.

Function of steroidogenic factor 1 domains in nuclear localization, transactivation, and interaction with transcription factor TFIIB and c-Jun

Normal endocrine development and function require nuclear hormone receptor SF-1 (steroidogenic factor 1). To understand the molecular mechanism of SF-1 action, we have investigated its domain function by mutagenesis and functional analyses. Our mutant studies show that the putative AF2 (activation function 2) helix located at the C-terminal end is indispensable for gene activation. SF-1 does not have an N-terminal AF1 domain. Instead, it contains a unique FP region, composed of the Ftz-F1 box and the proline cluster, after the zinc finger motif. The FP region interacts with transcription factor IIB (TFIIB) in vitro. This interaction requires residues 178-201 of TFIIB, a domain capable of binding several transcription factors. The FP region also mediates physical interaction with c-Jun, and this interaction greatly enhances SF-1 activity. The putative SF-1 ligand, 25-hydroxycholesterol, has no effects on these bindings. In addition, the Ftz-F1 box contains a bipartite nuclear localization signal (NLS). Removing the basic residues at either end of the key nuclear localization sequence NLS2.2 abolishes the nuclear transport. Expression of mutants containing only the FP region or lacking the AF2 domain blocks wild-type SF-1 activity in cells. By contrast, the mutant having a truncated nuclear localization signal lacks this dominant negative effect. These results delineate the importance of the FP and AF2 regions in nuclear localization, protein-protein interaction, and transcriptional activation.

Inactivation of the monocistronic rca gene in Anabaena variabilis suggests a physiological ribulose bisphosphate carboxylase/oxygenase activase-like function in heterocystous cyanobacteria

There was no discernible effect after incubating recombinant Anabaena Rubisco and carboxyarabinitol 1-phosphate with the product of the Anabaena rca gene. Since the unactivated cyanobacterial Rubisco is not readily inhibited by ribulose 1,5-bisphosphate and fallover is not observed, a genetic basis for the function of the Rubisco activase-like gene (rca) was sought. The monocistronic rca gene was inactivated in vivo and resulting mutant strains of A. variabilis were found to be incapable of synthesizing immunologically detected RCA protein. The requirement for the product of the rca gene in the light was further examined by measuring Rubisco activity in permeabilized whole cells of wild-type and rca mutant strains at different light intensities. In a 1% CO2-air atmosphere, inactivation of rca reduced the ability of A. variabilis to elevate Rubisco activity under high light (73 micromol quanta m(-2) s(-1)), but had little effect under low light (8 micromol m(-2) s(-1)). For air-grown cultures, differences in the rates exhibited by the wild-type and rca mutant to fully activate Rubisco during a whole-cell assay were enhanced by increases in light intensity. The significance of the rca mutation was underlined by effects on growth as, unlike the wild-type, growth rates did not increase after cells transferred from low to high light intensities. Higher exogenous CO2 concentrations (1%) were required to sustain a normal growth rate for the A. variabilis rca mutant. When grown in air levels of CO2, the rca mutant not only needed longer times to double in cell density but also exhibited greatly diminished Rubisco activity compared with the wild-type strain. Despite the unusual properties of cyanobacterial Rubisco, these results suggest a physiological role for the product of the rca gene in maximizing the activity of Rubisco in heterocystous cyanobacteria.

Identification of heparin-binding EGF-like growth factor as a target in intercellular regulation of epidermal basal cell growth by suprabasal retinoic acid receptors

The role of retinoic acid receptors (RARs) in intercellular regulation of cell growth was assessed by targeting a dominant-negative RARalpha mutant (dnRARalpha) to differentiated suprabasal cells of mouse epidermis. dnRARalpha lacks transcriptional activation but not DNA-binding and receptor dimerization functions. Analysis of transgenic mice revealed that dnRARalpha dose-dependently impaired induction of basal cell proliferation and epidermal hyperplasia by all-trans RA (tRA). dnRARalpha formed heterodimers with endogenous retinoid X receptor-alpha (RXRalpha) over RA response elements in competition with remaining endogenous RARgamma-RXRalpha heterodimers, and dose-dependently impaired retinoid-dependent gene transcription. To identify genes regulated by retinoid receptors and involved in cell growth control, we analyzed the retinoid effects on expression of the epidermal growth factor (EGF) receptor, EGF, transforming growth factor-alpha, heparin-binding EGF-like growth factor (HB-EGF) and amphiregulin genes. In normal epidermis, tRA rapidly and selectively induced expression of HB-EGF but not the others. This induction occurred exclusively in suprabasal cells. In transgenic epidermis, dnRARalpha dose-dependently inhibited tRA induction of suprabasal HB-EGF and subsequent basal cell hyperproliferation. Together, our observations suggest that retinoid receptor heterodimers located in differentiated suprabasal cells mediate retinoid induction of HB-EGF, which in turn stimulates basal cell growth via intercellular signaling. These events may underlie retinoid action in epidermal regeneration during wound healing.

Function of steroidogenic factor 1 (SF1) ligand-binding domain in gene activation and interaction with AP1

The nuclear receptor SF1 is an essential mediator in ventromedial hypothalamus-pituitary-gonadal development. As with other nuclear receptors, SF1 possesses a DNA-binding domain composed of two zinc fingers and a ligand-binding domain containing a ligand-dependent activation sequence termed AF2. To dissect the domain function of SF1, we examined various SF1 mutants in mouse adrenocortical Y1 cells and human placental JEG3 cells. Destruction of the AF2 structure removed 73-90% transactivation activity, suggesting that AF2 is indispensable for transactivation. Mutants carrying the DNA-binding domain but lacking the AF2 or the ligand-binding domain blocked the activity of normal SF1. Disrupting the zinc finger diminished the dominant negative effect of mutant. Cotransfection of SF1 with AP1 showed that the two transcription factors cooperated to activate gene expression. Some mutants lost the synergistic action with AP1, while some retained partial activity. These experiments delineate the functional domains of SF1.

Maximum activity of recombinant ribulose 1,5-bisphosphate carboxylase/oxygenase of Anabaena sp. strain CA requires the product of the rbcX gene

Filamentous cyanobacteria of the genus Anabaena contain a unique open reading frame, rbcX, which is juxtaposed and cotranscribed with the genes (rbcL and rbcS) encoding form I ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Plasmid constructions containing the genes from Anabaena sp. strain CA were prepared, and expression studies in Escherichia coli indicated that the product of the rbcX gene mimicked the ability of chaperonin proteins to facilitate the proper folding of recombinant RubisCO proteins. The purified recombinant Anabaena sp. strain CA RubisCO, much like the RubisCO enzymes from other cyanobacteria, was shown not to undergo inhibition of activity during a time course experiment, and the properties of this chaperoned recombinant protein appear to be consistent with those of the enzyme isolated from the native organism.

Temperature extremes and mortality from coronary heart disease and cerebral infarction in elderly Chinese

We studied the relation between outdoor temperature and mortality rates from cardiovascular disease in Taiwan from 1981 to 1991. In 11 years, there were 30,085, 21,750, and 39,818 deaths from coronary artery disease, cerebral infarction, and cerebral haemorrhage, respectively, among 7.6 million residents aged 25 and over in selected areas where climate was recorded. A temperature-mortality relation was especially apparent in the elderly. A U-shaped relation was observed between temperature and mortality from coronary artery disease and cerebral infarction. The range corresponding to least deaths from coronary artery disease (26-29 degrees C) and cerebral infarction (27-29 degrees C) was higher than that in countries with colder climates. In the elderly, the risk of cerebral infarction at 32 degrees C was 66% higher than that at 27-29 degrees C; the risk increased by 3.0% per 1 degree C reduction from 27-29 degrees C. The risk of coronary artery disease at 32 degrees C was 22% higher than that at 26-29 degrees C; below 26-29 degrees C, the risk increased by 2.8% per 1 degree C reduction. Mortality from cerebral haemorrhage decreased with increasing temperature at a rate of 3.3% per 1 degree C. These results imply a pathophysiological difference between thromboembolic and haemorrhagic cardiovascular diseases. Poor thermoregulation in older people may precipitate cardiovascular disease events.

Transcription control of ribulose bisphosphate carboxylase/oxygenase activase and adjacent genes in Anabaena species

The gene encoding ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) activase (rca) was uniformly localized downstream from the genes encoding the large and small subunits of RubisCO (rbcL and rbcS) in three strains of Anabaena species. However, two open reading frames (ORF1 and ORF2), situated between rbcS and rca in Anabaena sp. strain CA, were not found in the intergenic region of Anabaena variabilis and Anabaena sp. strain PCC 7120. During autotrophic growth of Anabaena cells, rca and rbc transcripts accumulated in the light and diminished in the dark; light-dependent expression of these genes was not affected by the nitrogen source and the concentration of exogenous CO2 supplied to the cells. When grown on fructose, rca- and rbc-specific transcripts accumulated in A. variabilis regardless of whether the cells were illuminated. Transcript levels, however, were much lower in dark-grown heterotrophic cultures than in photoheterotrophic cultures. In photoheterotrophic cultures, the expression of the rca and rbc genes was similar to that in cultures grown with CO2 as the sole source of carbon. Although the rbcL-rbcS and rca genes are linked and are in the same transcriptional orientation in Anabaena strains, hybridization of rbc and rca to distinct transcripts suggested that these genes are not cotranscribed, consistent with the results of primer extension and secondary structure analysis of the nucleotide sequence. Transcription from ORF1 and ORF2 was not detected under the conditions examined, and the function of these putative genes remains unknown.

The Rubisco activase (rca) gene is located downstream from rbcS in Anabaena sp. strain CA and is detected in other Anabaena/Nostoc strains

A gene encoding ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase (rca) was found downstream from the rbcLrbcS operon in the heterocystous cyanobacterium Anabaena sp. strain CA. Two unknown open reading frames were shown to be located between rbcS and rca in strain CA and all the genes, rbcLrbcS, ORF1, ORF2, and rca were in the same transcriptional orientation. The deduced amino acid sequence of the Anabaena Rubisco activase showed both similarities and differences to the plant enzyme with considerable differences at the carboxy and amino termini. Proposed ATP-binding sites were conserved in the cyanobacterial protein. Recombinant cyanobacterial Rubisco activase, however, reacted with antisera to spinach Rubisco activase. Hybridization studies, using the Anabaena sp. strain CA rca gene as a heterologous probe, detected homologous sequences in heterocystous Anabaena/Nostoc strains but not in unicellular or nonheterocystous filamentous cyanobacteria, suggestive of a close evolutionary relationship of chloroplasts and heterocystous cyanobacteria.

Direct effects of thymopentin (Arg-Lys-Asp-Val-Tyr) on cholinergic agonist-induced slow inactivation of nicotinic acetylcholine receptor function

The effects of thymopentin (TP-5) on the cholinergic agonist-induced inactivation of function (desensitization) of the nicotinic acetylcholine receptor (nAChR) were explored using two systems, 1) Torpedo californica electroplax nAchR reconstituted into phospholipid vesicles and 2) T. californica nAChR expressed, in Xenopus laevis oocytes, from in vitro synthesized RNA transcripts. The pentapeptide did not modify the equilibrium binding of 125I-alpha-bungarotoxin, but toxin rate binding assays in the presence of the cholinergic agonist carbamylcholine (Carb) revealed that it shortened the time course of the Carb-induced nAchR transition to the high affinity, desensitized state. Thymopentin (but not thymosins alpha 1 and beta 4) accelerated the slow inactivation of nAchR-mediated 86Rb+ influx, as measured by the first-order decrease in the Carb-induced 86Rb+ transport into the reconstituted vesicles. The decay of the acetylcholine-induced current from Torpedo receptor expressed in oocytes was also accelerated by TP-5. The pentapeptide had no ion channel-blocking or agonist activity of its own and exhibited a requirement for Ca2+ to express its effects. On the basis of these results, it is proposed that TP-5 has a direct effect on the nAChR, resembling that of noncompetitive blockers, as opposed to an indirect mechanism of action via the activation of specific metabolic pathways.

[Differential diagnosis of nipple discharge]

An analysis of results of contrast mammography in 42 women having spontaneous, persistent and unilateral discharge from the nipple of the breast of serous, serous-hemorrhagic and hemorrhagic character was made. The cause of the discharge was found to be intraductal papillomas and cystadenopapillomas in 55% of the cases, breast cancer--in 2% which were not diagnosed by noncontrast mammography.

[Research on thixotropic parameters of whole blood from Chinese adult subjects]

This study measured the thixotropic parameters of whole blood from 314 healthy subjects (154 women, 160 men) with our modified method by Low Shear-30 Rheometer according to Huang's equation. We suggested the range of normal values of thixotropic parameters from man and woman group. The results demonstrated that no significant differences existed in the plasma viscosity (eta p) and fibrinogen between man and woman group. Man group had significantly higher values than those in woman group in hematocrit (HCT), yield stress (tau 0), Newtonian contribution of viscosity (mu), non-Newtonion contribution of viscosity (eta s-mu), apparent viscosity at 2.37s-1 (eta s), the equilibrium value of the structural parameter (A) and apparent kinetic rate constant of rouleaux breakdown (ARC). The man and woman groups could be separately divided into five subgroups on the basis of age. All parameters were compared with one another and treated statistically. We found that the levels of fibrinogen and eta p had an increasing trend with aging. In the old subgroup (greater than or equal to 60 years) of man and woman, HCT, tau 0, mu, eta s, (eta s-mu) and A had significantly lower values than those in young and middle age subgroups. However, it was very interesting that there were differences of ARC versus age between the man and woman groups, i.e., ARC in the man subgroup 3, 4 had lower values and in the woman subgroup 2, 3, 4 had higher values than their respective older subgroups did.

The mouse bioassay for the detection of estrogenic activity in rodent diets: I. A standardized method for conducting the mouse bioassay

A standardized procedure was developed for conducting the mouse bioassay for detecting estrogenic activity in rodent diets. Studies were conducted with CD-1 mice to determine the appropriate weaning age and length of bioassay period. Uterine growth curves were generated from mice weaned at 15 days of age and fed a negative control diet until 28 days of age. These mice showed slow regular increases in uterine weights from 15 22 days of age followed by rapid uterine growth in some mice from 24 to 28 days of age. Estrogenic bioassays using female mice weaned at 15 days of age and fed the positive control diets containing 4 or 6 ppb diethylstilbestrol (DES) demonstrated significant (P less than 0.05) increases in uterine weight and in uterus to body weight (U:BW) ratios over those of mice fed the negative control diet without DES for 5, 7 or 9 days after weaning. In contrast, mice weaned at 17 days of age showed significant (P less than 0.05) increases in uterine weight and in U:BW ratios only at 5 days after weaning. Six ppb DES was required in the positive control diet to produce a 1.5 fold increase in the U:BW ratio over those of mice fed the negative control diet. It was concluded that mice should be weaned at 15 days of age and that the bioassay period should be terminated at 7 days, when the mice are 22 days old, for best reproducible results. The criteria for a valid bioassay should include the demonstration of a significant statistical increase in the U:BW ratios of mice fed the DES positive diet over those of mice fed the negative control diet.

Morphological characterization of transformed colonies in rat tracheal epithelial cell cultures exposed to carcinogen

The purpose of the studies described in this and the accompanying paper (D.J. Fitzgerald et al., Cancer Res., 46:4642-4649, 1986) was to define the transformed colonies of the rat tracheal epithelial cell transformation system (see P. Nettesheim and J.C. Barrett, CRC Crit. Rev. Toxicol., 12: 215-239, 1984) in terms of differentiation and growth characteristics. Exposure of low-density primary rat tracheal epithelial cell cultures to N-methyl-N'-nitro-N-nitrosoguanidine results in the development of growth-altered colonies of different sizes and morphologies, which can be readily scored 5 wk after treatment. These colonies were classified into four morphological types (I to IV) based on their light microscopic and ultrastructural features. Colonies designated as types I and II were small, had a low cell density, and were composed principally of large, pale-staining (Giemsa) flattened cells with a low nuclear/cytoplasmic ratio. Examination of the fine structure of these colonies revealed a monolayer of extremely attenuated cells containing well-developed Golgi complexes, endoplasmic reticulum, numerous secondary lysosomes, but few tonofilaments and desmosomes. Colonies of types III and IV were large, basophilic (Giemsa), high-density colonies, consisting primarily of closely packed, small, round cells with high nuclear/cytoplasmic ratio. Analysis of the fine structure of these colonies revealed two to four stratified layers of poorly differentiated cells and cells having features of keratinocyte differentiation, as evidence by abundant tonofilament bundles, well-developed desmosomes, and occasional keratohyaline granules. Differential cell counts were carried out at the ultrastructural level on pooled cells from each colony type (except type I); approximately 90% of the cells from type II colonies were large, electron-lucent cells, while this cell type comprised only 20 to 30% of the cells of colonies of types III and IV. The predominant cell type (approximately 60%) in colonies of types III and IV showed clear signs of keratinocyte differentiation. Type IV colonies contained a significantly larger proportion (greater than 20%) of small, poorly differentiated cells than type III (6%) and type II (1%) colonies. A combined autoradiographic and ultrastructural study revealed that the small, poorly differentiated cells were most active in synthesizing DNA and had a labeling index of 60%. Other cell types were far less frequently labeled, particularly the large, electron-lucent cells which had a labeling index of only 10%. Morphometric measurements on fixed and stained colonies disclosed that each colony type differs markedly in cell population size.(ABSTRACT TRUNCATED AT 400 WORDS)

[Individual prognosis in patients with an edematous variant of breast cancer]

The probability procedure of Neuman -Pearson (method of maximal credibility) was used for the quantitative description of factors of prognosis of edematous form of breast cancer in terms of specific gravities . A complex evaluation of these factors was carried out. The reliability of prognosis made on the basis of the factors under study was as high as 79%.

[Peculiarities of the development of skeletal muscles in physiologically mature and immature mammals]

In one set of experiments, studies have been made on the time during which the membrane potential, action potential, total protein and the content of the dry substance of skeletal muscles of rats and dogs attain the values typical for adult animals. Chronologically, this time is 5-fold shorter in rats, than in dogs. In the other set of experiments, the same indices were studied in physiologically mature (with respect to calendar age) and immature rats and dogs. It was shown that in immature animals these indices are significantly lower than in mature ones. During natural development, physiologically immature organisms are the main objects of elimination at early postnatal stages via natural selection.

Comparative ontogenetic features of skeletal muscles in physiologically mature and immature mammals

One series of experiments investigated the time required by such indices of the states of skeletal muscles as membrane potential (MP), action potential (AP), and content of total protein and dense residue to acquire values approximating those found in adults. We established that these indices acquire values approximating those found in adults at the beginning of sexual maturation in both rats and dogs. Chronologically, these values require one-fifth the time to become established in rats as they do in dogs. Another series of experiments investigated the same indices in physiologically mature and immature organisms (rats and dogs). We established that they are much lower in immature than in mature organisms. We conclude that under conditions of natural development the main objects of elimination through natural selection in early developmental periods are physiologically immature organisms.