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Previous studies have disagreed about the presence of O-linked carbohydrate epitopes on gp 120 of HIV, although antibodies against short-chain O-linked glycans neutralize HIV infection and block syncytium formation in vitro. To settle this question, we analysed the O-linked glycans of gp 120 by chemical methods using purified HIV-1 gp 120 from cells infected with recombinant vaccinia virus solely expressing gp 160 or gp 120. Alkaline borohydride degradation of recombinant gp 120 released monosaccharides and also slightly larger structures (di/trisaccharides) by a beta-elimination, confirming the presence of simple O-linked oligosaccharides. The functional activity as neutralisation epitopes of the O-linked oligosaccharides expressed on recombinant gp 120 was preserved, since fusion between uninfected CD4+ cells and cells infected with recombinant vaccinia was blocked by monoclonal antibodies to the O-linked oligosaccharides of gp 120. Although the mechanism for HIV induction of O-linked oligosaccharide neoantigens is unknown, these results indicate that the O-linked neutralization epitopes are inherent to the glycoprotein itself, and that the unusual appearance of simple O-linked oligosaccharides on gp 120 is independent of any interaction between the host cell and retroviral genes other than env.

Recent studies have shown that preconditioning with hyperbaric oxygen (HBO) can reduce ischemic and hemorrhagic brain injury. We investigated effects of HBO preconditioning on traumatic brain injury (TBI) at high altitude and examined the role of matrix metalloproteinase-9 (MMP-9) in such protection.Rats were randomly divided into 3 groups: HBO preconditioning group (HBOP; n = 13), high-altitude group (HA; n = 13), and high-altitude sham operation group (HASO; n = 13). All groups were subjected to head trauma by weight-drop device, except for HASO group. HBOP rats received 5 sessions of HBO preconditioning (2.5 ATA, 100% oxygen, 1 h daily) and then were kept in hypobaric chamber at 0.6 ATA (to simulate pressure at 4000m altitude) for 3 days before operation. HA rats received control pretreatment (1 ATA, room air, 1 h daily), then followed the same procedures as HBOP group. HASO rats were subjected to skull opening only without brain injury. Twenty-four hours after TBI, 7 rats from each group were examined for neurological function and brain water content; 6 rats from each group were killed for analysis by HE staining and immunohistochemistry.Neurological outcome in HBOP group (0.71 +/- 0.49) was better than HA group (1.57 +/- 0.53; p0.05). Preconditioning with HBO significantly reduced percentage of brain water content (86.24 +/- 0.52 vs. 84.60 +/- 0.37; p0.01). Brain morphology and structure seen by light microscopy was diminished in HA group, while fewer pathological injuries occurred in HBOP group. Compared to HA group, pretreatment with HBO significantly reduced the number of MMP-9-positive cells (92.25 +/- 8.85 vs. 74.42 +/- 6.27; p0.01).HBO preconditioning attenuates TBI in rats at high altitude. Decline in MMP-9 expression may contribute to HBO preconditioning-induced protection of brain tissue against TBI.

To analyze the constituents from the rhizomes of Atractylodes lancea and A. chinensis in essential oils.GC-MS method was used.32 and 29 compounds were identified respectively.The main constituents in the essential oils from the rhizome of A. chinensis are beta-eudesmol or a mixture of beta-eudesmol and atractylone, whereas from that of A. lancea are hinesol, a mixture of beta-eudesmol and atractylone, and atractylone.

Newborn macaques were vaccinated against a chimeric simian human immunodeficiency (SHIV) virus, SHIV-vpu+, by DNA priming and boosting with homologous HIV-1 gp160. Following SHIV-vpu+ challenge, containment of infection was observed in 4 of 15 animals given DNA priming/protein boost vaccination and in three of four animals given gp160 boosts only. Rechallenge with homologous virus of six animals that contained the first challenge virus resulted in rapid viral clearance or low viral loads. Upon additional rechallenge with heterologous, pathogenic SHIV89.6P, four of these six animals maintained normal CD4+ T-cell counts with no or limited SHIV89.6P infection. Our data suggest that humoral and cellular immune mechanisms may have contributed to the containment of SHIV89.6P; however, viral interference with SHIV-vpu+ could also have played a role. Our results indicate that immunogenicity and efficacy of candidate AIDS vaccines are not affected when vaccination is initiated during infancy as compared with later in life.

A model of vertical HIV transmission was developed using oral HIV-2(287) exposure of newborn Macaca nemestrina. The minimal Animal Infectious Dose for this oral route was found to be 10-fold higher than that for atraumatic viral transmission across other mucosal membranes (vaginal/rectal) of juvenile macaques. However, once infection was established, viral replication was rapid and plasma viremia could be detected by reverse-transcriptase polymerase chain reaction and viral co-culture within 1 week following exposure. No animal was resistant to infection and all macaques initially exposed to a subinfectious viral inoculum were subsequently infected by re-exposure of mucosal membranes. Higher viral load during primary infection correlated with a more rapid CD4 depletion; however, all HIV-2(287)-infected animals developed CD4 depletion during the observation period. This animal model can now be used to study early viral replication in the presence and absence of anti-retroviral agents to help identify conditions to reduce vertical HIV transmission in human newborns.

Nanocrystalline NdFeB magnets were prepared by spark plasma sintering (SPS) and SPS followed by HD using melt spun ribbons as the starting materials. The microstructure of SPSed and HDed magnets were analyzed. The effects of process including temperature and compression ratio on the microstructure and properties were investigated. High magnetic properties were obtained in anisotropic HDed magnets. The combination of Zn and Dy additions was successfully employed to improve the coercivity and thermal stability of the SPSed magnets. Open recoil loops were found in these magnets with Nd-rich composition and without soft magnetic phase for the first time. The relationship between the recoil loops and microstructure for SPS and HD NdFeB magnets were investigated. The investigations showed that the magnetic properties of SPS+HDed magnets are related to the extent of the aggregation of Nd-rich phase, which was formed during HD due to existence of porosity in SPSed precursor. Large local demagnetization fields induced by the Nd-rich phase aggregation leads to the open loops and significantly reduced the coercivity. By reducing the recoil loop openness, the magnetic properties of HDed NdFeB magnets were successfully improved.

The V3 hypervariable region of HIV-1 surface protein has been identified as a major determinant for viral tropism and coreceptor usage. However, the role of the highly conserved N-linked glycan at the V3 loop remains controversial. To further examine its role in viral infection, we introduced a conservative amino acid substitution (asparagine to glutamine) in the V3-proximal glycosylation motif (Asn-X-Ser/Thr) in the surface glycoprotein of a CXCR4-using virus (BRU), a CCR5-using virus (SF162), and a dual-tropic virus (89.6). The effect of the mutation was determined by complementation assays, and by infectivity on CEMx174 and U373-MAGI cells expressing either CXCR4 or CCR5. The mutation resulted in decreased CXCR4 usage by SHIV89.6, but increased usage by BRU. Similarly, it abrogated CCR5 usage by SHIV89.6, but had no effect on SF162. This effect was not dependent on the specific amino acid substitution used, because a threonine-toalanine mutation in the same motif in 89.6 Env yielded identical results as the asparagine-to-glutamine mutation. These findings support the notion that multiple factors, including glycosylation at V3, contribute to coreceptor usage and that the particular effects exerted by the N-linked glycan itself appear to be isolate dependent.

With few exceptions, humans are the only species known to develop acquired immunodeficiency syndrome (AIDS) after human immunodeficiency virus (HIV) infection. We report here that an isolate of HIV type 2, EHO, readily established persistent infection in 100% of Macaca nemestrina in three consecutive transmission studies. Of the eight infected animals, five showed persistently high virus load and six developed AIDS-like diseases or CD4+ cell depletion within 4 years of infection. The pathology and clinical signs closely parallel those of HIV-1 infection of humans, including lymphadenopathy, anemia, CD4+ cell depletion, and opportunistic infections. A cell-free virus stock was established from the lymph nodes of an animal that developed AIDS-like diseases. This virus, HIV-2/287, was highly pathogenic in M. nemestrina, causing CD4+ cell depletion within 2-8 weeks postinfection. While both HIV-2 EHO and HIV-2/287 use predominantly CXCR4, the latter shows greatly enhanced replicative capacity in macaque peripheral blood mononuclear cells (PBMCs). The establishment of a human immunodeficiency virus that causes rapid and reproducible CD4 cell depletion in macaques could facilitate the study of HIV pathogenesis and the development of effective vaccines and therapy against AIDS.

The preclinical evaluation of the efficacy of potential vaccines against AIDS requires challenge models. The experimental infection of macaques with simian immunodeficiency virus, human immunodeficiency virus type 2 (HIV-2) or chimeric viruses have proven to be most valuable. The progress made using simian models to assess the efficacy and identify the correlates or mechanism of protection by whole inactivated virus, live attenuated virus or recombinant sub-unit vaccines is reviewed. It is possible to conclude from these studies that an effective AIDS vaccine is feasible. Furthermore, it is likely that these different vaccine approaches protect through distinct mechanisms. These results provide a scientific basis for the development and selection of suitable candidate human AIDS vaccines for testing in humans.

The study was carried out for reviewing the hypothesis on the relationship between integrated fish farming (IFF) and human influenza A pandemic using study methods of longitudinal epidemiology, ecology and serology. Four rural villages with IFF, non-IFF and non-fish farming, selected from two provinces (Henan and Shandong of PRC) were investigated for the status about human influenza A epidemic and infections with human, duck, swine influenaz A viruses in those communities. The results put forward views on that there is no relation between IFF and the increase of incidence rate, infection rate and antibodies level to human influenza A virus. Duck may play an important role in the increase of infection rate to human influenza A viruses among human communities. Pigs seem not to play obvious role in the increase of infection rate to human influenza A viruses among human communities. Human, duck, swine influenza A viruses may spread among human duck and pigs communities interchangably.

We investigated the ability of human recombinant interleukin-7 (IL-7) to enhance the immune responses of mice vaccinated with either the alum-associated or liposome-formulated recombinant human immunodeficiency virus (HIV)-envelope protein, env-2-3SF2 (a nonglycosylated denatured gp 120 of HIV-1SF2 produced in genetically engineered yeast). Pathogen-free (C3H) mice were vaccinated on days 0, 14, and 28 with 10 micrograms of either the alum-associated env-2-3SF2 or liposome-formulated env-2-3SF2, both containing a lipophylic muramyl tripeptide, MTP-PE. Liposome-formulated IL-7 (5 micrograms/mouse) or empty liposomes were given on days 7, 14, 21, and 28. Antibody response against the immunized antigen, evaluated on day 21 and day 35 or 42, showed that liposome-formulated antigen induced higher antibody titer than did alum-associated antigen, and these antibody responses can be enhanced by concurrent administration of IL-7 liposomes. Spleen cells were harvested on day 21 and day 35 or 42 to evaluate cytotoxic T lymphocyte responses directed against autologous cells infected with vaccinia virus-expressing HIV-envelope protein. Mice treated with liposome-formulated antigen expressed the highest cytotoxic t-lymphocyte (CTL) activity, regardless of whether IL-7 liposome was given as an immune potentiator. In contrast, spleen cells from mice vaccinated with alum-associated antigen exhibited minimal CTL response, which was enhanced by concurrent IL-7 liposome treatment. Collectively, IL-7 liposome treatment enhanced the antibody production of the alum-associated or liposome-formulated env-2-3SF2, whereas its enhancement of CTL activity was detected only in mice vaccinated with alum-associated antigen.

An original error on Huzhang and Tiannanxing in Li Shizhen's "Bencao Gangmu" (Compendium of Materia Medica, 1596) is corrected in this paper. The conclusion is that Huzhang in "Shen Nong's Materia" (around 200) should be the tuber of Pinellia pedatisecta and Tiannanxing in "Kaibao Bencao" (974) the tuber of Arisaema heterophyllum but they were merged or confused by Li Shizhen. The former, in fact, has been cultivated, marketed, exported and used medically for its high quality, but it has disappeared from herbal literatures owing to Li's error. Therefore, the above-mentioned correction should be accepted in the next edition of Pharmacopoea of the people's Republic of China.

Two Macaca fascicularis with preexisting immunity to vaccinia virus were immunized twice with recombinant vaccinia virus expressing SIVmne gp160. Their SIV-specific antibody responses were lower than that of vaccinia-naive animals immunized similarly. Upon repeated boosting with gp160, the SIV-specific antibody titers in vaccinia-primed animals reached similar levels as vaccinia-naive animals and with comparable neutralizing titers. Both animals were protected against repeated intravenous challenge with low-dose SIVmne E11S. These results are significant because SIVmne E11S infection in M. fascicularis is pathogenic and leads to AIDS-like diseases.

Recombinant vaccinia virus expressing the envelope proteins of type D retrovirus-Washington (SRV-2/W) was used to immunize macaques against SRV-2 infection. Four immunized macaques which had resisted a prior low-dose challenge were rechallenged with a high dose (10(6) infectious particles) of SRV-2 two years after being immunized. All four non-immunized control macaques became infected, but the four vaccinated animals resisted this intravenous challenge, as determined by the inability to detect SRV-2 in peripheral blood mononuclear cells and by the lack of seroconversion to new viral antigens.

Human papillomavirus (HPV) type 16 has been implicated in the etiology of cervical carcinomas, but it is unknown whether HPV-specific immunity can function in controlling the growth of HPV-associated carcinomas. We previously demonstrated that CD8+ T lymphocytes can inhibit the in vivo outgrowth of murine tumor cells transfected with the HPV-16 E7 gene and have now established a murine model to study the CTL responses to the E6 oncoprotein of HPV-16. Immunization of C3H/HeN mice with syngeneic fibroblasts expressing a transfected HPV-16 E6 gene induced regression of transplanted tumors expressing this gene. Populations of CTL isolated from the spleens of mice whose E6+ tumors had regressed were shown to specifically lyse E6+ target cells. The cytolytic activity was mediated by CD8+ CTL in a MHC restricted pattern. These data and our previous findings with transfected tumor cells expressing the E7 gene, support the conclusion that tumor cells associated with HPV-16 can be inhibited by CTL specific for molecules encoded by the HPV-16 E6 and E7 genes.

Immunization with anti-idiotypic antibodies can induce cell-mediated and humoral antitumor immunity in animal models. This immunity can sometimes cause tumor destruction. However, more needs to be learned about how best to induce the type of immune response that is responsible for tumor destruction, since the presence of anti-idiotypic antibodies has been shown occasionally to enhance, rather than to inhibit, tumor growth. There is evidence suggesting that immunization of human cancer patients with Ab2 can have therapeutic benefit, and also that patients who mount a vigorous Ab2 response following treatment with an Ab1 may do clinically better than those who do not make any Ab2. Although the generation of Ab2 related to infused antitumor Ab1 does not cause tumor rejection in the majority of patients, and although the clinical data from patients given Ab2 are scarce, the suggestion that Ab2 may cause destruction of human cancers indicates that further work in this area may become rewarding.

We performed theoretical analysis on nanodiamonds (NDs) generated by pulsed-laser ablation to investigate its growth dynamics. The final size of NDs was calculated by combining the growth velocity with growth time. The result shows that the radius and density of plasma plume determine the cooling velocity, and the growth time correlates with the cooling velocity. Theoretical calculations are in good agreement with experimental results and give reasonable explanation on the formation of ultrafine NDs.

Effects of the K+ channel blocking agent, glyburide, on the actions of two K+ channel openers, BRL 34915 (cromakalim) and P 1060 (Leo), a potent pinacidil derivative (N-(t-butyl)-N"-cyano-N'-3-pyridyl-guanidine), were ascertained. Tension responses and 86Rb fluxes in rat portal vein strips and single channel electrophysiological recordings in enzymatically dissociated rat portal vein cells were obtained. Glyburide (0.3 microM) increased spontaneous contractile activity and caused concentration-dependent shifts in the relaxation responses to BRL 34915 and P 1060. Increases in 86Rb efflux were obtained only at much higher concentrations of BRL 34915 or P 1060, and these increases were blocked only at higher concentrations of glyburide (5.0 microM). BRL 34915 and P 1060 specifically increase the open-state probability of the Ca+(+)-activated K+ (maxi-K+) channel, and these actions are blocked by glyburide and also by charybdotoxin. Changes in single channel activity and contractile responsiveness occur at similar concentrations of agonists and antagonists. Thus, the membrane channel in rat portal vein affected by glyburide, BRL 34915 and P 1060 appears to be the Ca+(+)-activated maxi-K+ channel (that does not show ATP dependence under the conditions of these experiments). Concentrations of agonists and antagonists effective on maxi-K+ channel activity correspond to those affecting contractile responsiveness and are lower than those eliciting changes in 86Rb flux.

Previous studies had tested the susceptibility of two macaque species, Macaca nemestrina and M. mulatta, to infection with the primate lymphotropic lentivirus SIVmne. In this report we describe the results obtained after infecting eleven M. fascicularis with SIVmne. Six of the animals had previously been immunized with a recombinant vaccinia virus expressing the envelope gene of HIV-1. All eleven animals became seropositive. To date ten animals have died 43 to 155 weeks post infection of an AIDS-like disease.

The permeation properties of the 147-pS Ca2+-activated K+ channel of the taenia coli myocytes are similar to those of the delayed rectifier channel in other excitable membranes. It has a selectivity sequence of K+ 1.0 greater than Rb+ 0.65 greater than NH4+ 0.50. Na+, Cs+, Li+, and TEA+ (tetraethylammonium) are impermeant. Internal Na+ blocks K+ channel in a strongly voltage-dependent manner with an equivalent valence (zd) of 1.20. Blockade by internal Cs+ and TEA+ is less voltage dependent, with d of 0.61 and 0.13, and half-blockage concentrations of 88 and 31 mM, respectively. External TEA+ is about 100 times more effective in blocking the K+ channel. All these findings suggest that the 147-pS Ca2+-activated K+ channel in the taenia myocytes, which functions physiologically like the delayed rectifier, is the single-channel basis of the repolarizing current in an action potential.

In single myocytes of the guinea pig taenia coli, dispersed by enzymatic digestion, the late outward current is carried by K+. It has both a Ca2+-activated component and a voltage-dependent component which is resistant to external Co2+. The reversal potential is -84 mV, and the channel(s) for it are highly selective to K+. At 33 degrees C, the activation follows n2 kinetics, with a voltage-dependent time constant of 10.6 ms at 0 mV, which shortens to 1.7 ms at +70 mV. Deactivation follows a single-exponential time course, with a voltage-dependent time constant of 11 ms at -50 mV, which lengthens to 33 ms at -20 mV. During a 4.5-s maintained depolarization, IK inactivates, most of it into two exponential components, but there is a small noninactivating residue. It is surmised that during an action potential under physiological conditions, there is sufficient IK to cause repolarization.

Using the tight-seal voltage-clamp method, the ionic currents in the enzymatically dispersed single smooth muscle cells of the guinea pig taenia coli have been studied. In a physiological medium containing 3 mM Ca2+, the cells are gently tapering spindles, averaging 201 (length) x 8 microns (largest diameter in center of cell), with a volume of 5 pl. The average cell capacitance is 50 pF, and the specific membrane capacitance 1.15 microF/cm2. The input impedance of the resting cell is 1-2 G omega. Spatially uniform voltage-control prevails after the first 400 microseconds. There is much overlap of the inward and outward currents, but the inward current can be isolated by applying Cs+ internally to block all potassium currents. The inward current is carried by Ca2+. Activation begins at approximately -30 mV, maximum ICa occurs at +10-+20 mV, and the reversal potential is approximately +75 mV. The Ca2+ channel is permeable to Sr2+ and Ba2+, and to Cs+ moving outwards, but not to Na+ moving inwards. Activation and deactivation are very rapid at approximately 33 degrees C, with time-constants of less than 1 ms. Inactivation has a complex time course, resolvable into three exponential components, with average time constants (at 0 mV) of 7, 45, and 400 ms, which are affected differently by voltage. Steady-state inactivation is half-maximal at -30 mV for all components combined, but -36 mV for the fast component and -26 and -23 mV for the other two components. The presence of multiple forms of Ca2+ channel is inferred from the inactivation characteristics, not from activation properties. Recovery of the fast channel occurs with a time-constant of 72 ms (at +10 mV). Ca2+ influx during an action potential can transfer approximately 9 pC of charge, which could elevate intracellular Ca2+ concentration adequately for various physiological functions.

Currents through single potassium channels were studied in cell-attached or inside-out patches from collagenase-dispersed smooth muscle cells of the guinea pig taenia coli. Under conditions mimicking the physiological state with [K+]i = 135 mM: [K+]o = 5.4 mM, three distinct types of K+ channel were identified with conductances around 0 mV of 147, 94, and 63 pS. The activities of the 94- and 63-pS channel were observed infrequently. The 147-pS channel was most abundant. It has a reversal potential of approximately -75 mV. It is sensitive to [Ca2+]i and to membrane potential. At -30 mV, the probability of a channel being open is at a minimum. At more positive voltages, the probability follows Boltzman distribution. A 10-fold change in [Ca2+]i causes a 25-mV negative shift of the voltage where half of the channels are open; an 11.3-mV change in membrane potential produces an e-fold increase in the probability of the channel being open when P is low. At voltages between -30 and -50 mV, the open probability increases in an anomalous manner because of a large decrease of the channel closed time without much change in the channel open time. This anomalous activity may play a regulatory role in maintaining the resting potential. The histograms of channel open and closed time fit well, respectively, with single and double exponential distributions. Upon step depolarizations by 100-ms pulses, the 147-pS channel opens with a brief delay. The delay shortens and both the number of open channels and the open time increase with increasing positivity of the potential. The averaged currents during the step depolarizations closely resemble the delayed rectifying outward K+ currents in whole-cell recordings.

Transcriptional studies of gene expression in coliphage λ reveal a complex set of interactions involving host RNA polymerase and the positive and negative regulatory functions of the phage genes N and cro, respectively. The N product, which is known for its anti-terminating effect, was also found to stimulate up to 4-fold the rate of transcription in the pL-N region, as determined by comparing induced λN+cro− and λN−cro− lysogens. In contrast, the Tof function of the cro gene product rapidly turns off transcription in the same region shortly after thermal induction of λN+cro+ lysogens. In λN−cro+ lysogens, however, this early turn-off was not observed, suggesting that the effective level of Tof function is reached only under N+ conditions. This N requirement for the early expression of Tof function in λ was also observed in induced prophages lacking all phage genes except those in the N-cI-cII region and, in addition, was found not to be satisfied by the analogous N product from phage λimm21. Furthermore, it was found that neither the phage mutation nutL− nor the host mutation nusA− blocks the effect of N protein on Tof function, indicating that antitermination per se is not required for Tof expression. However, since the expression of Tof function is blocked in the groN− host, which has an alteration in the β subunit of RNA polymerase, an interaction involving λ N protein and the host RNA polymerase might be required for Tof expression. Although these results are in apparent contradiction with the Fed phenomenon, we do find at late times after induction, when comparing N-cro+ N−cro− lysogens, that the rate of transcription under cro− conditions is up to 2-fold higher in the pL-proximal region and up to 10-fold higher in the exo-gam region. This indicates that the residual read-through transcription of red-gam genes under N− conditions is controlled by cro. One may conclude that, although the cro product may function through an operator-repressor type of interaction at the promoter-operator regions, its action at pL and pR may be augmented by more complex interactions involving Escherichia coli RNA polymerase and the λ regulatory protein N.

All cells transformed by adenovirus type 2 (Ad2) or SV40 carry viral DNA sequences. Often these sequences recombine with those of the host and are then passed on to the cells' descendants like any other part of the cellular genome (Sambrook et al. 1968). While a good deal is known of the number of integrated viral segments present in different cell lines and their general organization (Ketner and Kelly 1976; Botchan et al. 1976; Sambrook et al. 1977), nothing is known of the mechanism by which integration occurs, of the nature of the cellular attachment sites, of the exact locations of the integration sites in the viral genome, or of the mechanism by which viral DNA sequences are expressed. Direct access to the three latter problems has recently become possible with the development of techniques to propagate segments of eukaryotic DNA in prokaryotes

Normal and neoplastic mouse mammary epithelial cells were cultured in nutrient medium containing D-valine substituted for L-valine. Fibroblast overgrowth was prevented and epithelial cell functions and morphology were retained in cultures maintained in, D-valine medium up to 2 months. A nonenzymatic technique was devised to dissociate epithelial cell monolayers. The combined use of this dissociation buffer and D-valine nutrient medium made it possible to passage serially normal and neoplastic mammary epithelial cells. Normal cells were derived from mammary glands of animals stimulated with exogenous hormones for various periods. The period of in vivo hormonal stimulation influenced the ability of normal mammary epithelial cells to attach and proliferate in primary and serially passaged cultures. A greater proportion of cells derived from glands following 2 to 4 weeks of hormonal stimulation were recovered after replating and showed higher labeling indices during serial passage than cells from unstimulated or 5- to 7-week stimulated groups.

oop RNA, which is initiated at the po promoter and is 81 nucleotides long, can function as a leader sequence for the lambda immunity establishment transcription, previously believed to originate at a special promoter pre located in the y region. Thus, oop RNA seems to have a dual role, either favouring the lytic cycle as a primer for the initiation of lambda DNA replication, or leading to the establishment of lysogeny when elongated into the imm transcript, which directs synthesis of the repressor.

Cross-hybridization has been detected between corresponding regions of the genomes of bovine adenovirus type 3 and human adenovirus type 2. The most conserved region on the viral genomes encodes the hexon polypeptide. The nucleotide sequence of this region in bovine adenovirus type 3 has been determined. Comparison of the predicted amino acid sequences of the bovine adenovirus type 3 and human adenovirus type 2 hexon polypeptides reveals three regions of nonhomology.

Monoclonal antibodies (MAbs) to defined peptide epitopes on gp120 from human immunodeficiency virus type 1 were used to investigate the involvement of their epitopes in gp120 binding to the CD4 receptor. Recombinant vaccinia viruses were constructed that expressed either full-length gp120 (v-ED6), or a truncated gp120 lacking 44 amino acids at the carboxyl terminus (v-ED4). Binding of these glycoproteins to the CD4 receptor was detected directly with metabolically labeled gp120 or indirectly with the gp120 MAbs. Truncated gp120 from v-ED4 bound to CD4-positive cells less than 1/12 as well as gp120 from v-ED6, indicating that the C-terminal region of gp120, which is conserved in numerous isolates of human immunodeficiency virus type 1, is critical for CD4 binding. However, MAb 110-1, which recognizes a peptide contained in the region deleted from v-ED4 (amino acids 489 through 511), did not inhibit binding of gp120 to CD4. MAb 110-1 also reacted with gp120 bound to the CD4 receptor, indicating that the epitope for this antibody does not directly interact with CD4. A second MAb, 110-4, which recognizes a peptide epitope located between amino acids 303 and 323 and has potent viral neutralizing activity, also bound to gp120 on the CD4 receptor. Furthermore, pretreatment of gp120 with MAb 110-4 at concentrations approximately 1,000-fold higher than those required for complete virus neutralization inhibited subsequent CD4 binding by only about 65%. Taken together, these data suggest that neutralization mediated by antibody 110-4 does not result from binding of this MAb to the CD4-binding site of gp120.

PBL from chimpanzees immunized with a recombinant vaccinia virus that expresses HIV envelope glycoproteins ("env"), were found to proliferate after stimulation with HIV or with "env". Furthermore, CTL clones lytic for autologous target cells expressing HIV envelope glycoproteins were generated after stimulation of the chimpanzees' PBL with "env", indicating that immunization of these primates with a recombinant vaccinia virus primes HIV-specific CTL and also that HIV envelope glycoproteins serve as target antigens for CTL.

Controls of rightward transcription, initiated at the pR and the p′R promoters of induced λ lysogen, were studied by employing RNA-DNA hybridization techniques. Transcription initiated at the pR promoter is partially turned off by the cro gene product shortly after induction. However, this turn-off appears to depend on certain functions specified by the gene N product, since no such turnoff is observed in λN−cro+ lysogens. Furthermore, the product of gene N, in addition to its known antitermination effect at tR1, is found to stimulate pR-promoted transcription in the pR-cro region that is located upstream from both the N utilization site, nutR, and terminator tR1. Thus, the regulation of pR-promoted transcription by the N and cro products is analogous to that of PL-promoted transcription; we propose that similar mechanisms may be involved in the regulation of these transcripts. This study also indicates that the regulatory effect of the cro product is required for normal transcription from the p′R(pQ) promoter, since a reduced rate of transcription in the p′R-S-J region is observed in λcro− lysogens. This late regulatory effect of the cro product must be mediated through the phage DNA replication functions, because when λ replication is blocked by a P mutation, the cro product no longer stimulates p′R-promoted transcription. These results indicate that complex interactions between the transcriptional functions, including the regulatory products of N and cro, and the components of the replication machinery are involved in the control of the orderly development of phage λ.

The work in this paper has a twofold aim: 1 Verifying the Chinese drug "Banxia" in medicinal books before 1900 as the tuber of Pinellia ternata (Araceae), While P.ternata in Qizhou (Licheng County, Shandong Province) had been mistaken for P.tripartita which only grow in Japan; 2 proving young tuber of P.pedatisecta to be "Youba" which was confused with "Banxia" in some ancient medicinal books, while "Youba" has been regarded as Arisaema regens so far.

The Cooperative Medical System (CMS) and its barefoot doctors have been in decline in rural China for nearly a decade. In order to explore the reasons for this, in 1987 we carried out a survey of villagers, barefoot doctors, and local administrators in Fengxian, Shanggoa, and Loaan counties, where incomes are good, fair, and low, respectively. The state of the CMS in these counties was contrasted and the situations which prevailed in 1978, 1982, and 1985, when the system was, respectively, at its peak, had begun to decline, and had declined markedly, were compared. A random sample of villages was selected and all the barefoot doctors and administrators as well as a random sample of households were surveyed. The results indicate that health status (as measured by infant mortality, immunization coverage, and rate of infectious diseases) has decreased in areas where the CMS has declined, while per capita incomes increased. Concomitantly, villager's expenditures on health care have increased. Barefoot doctors and their patients were, however, reasonably happy with the system, and in its absence the doctors are no longer able to obtain ongoing training. The CMS was fiscally sound, and did not decline to the same extent in all areas--it continues to thrive in Fengxian, which is relatively affluent. It is concluded that the system probably declined because many local administrators perceived that it no longer enjoyed the backing of the central government.

Expression of genes int and xis was measured in ColE1 hybrid plasmids carrying the att-int-xis genes on Eco RI segment C of λ DNA. The requirements for synthesis of λ integration and excision functions by these hybrid plasmids are similar to those previously observed for intact phage. Since the plasmids lack the p l promoter, no xis product is made, but enough int product is produced constitutively to catalyze low but significant excisive recombination, if xis product is supplied. To obtain enough int function for integrative recombination, the c II and c III products must be supplied. Hybrid plasmids carrying a similar fragment from phages λ int-c (either a point mutation or an IS 2 insertion in gene xis ) express high levels of int function constitutively and promote integrative recombination even in the absence of c II and c III products. They also promote low but significant levels of excisive recombination even in the absence of xis function. For both λ and λ int-c fragments, int expression appears to depend on promoters within the fragment, but not on plasmid promoters, since such expression is independent from the orientation of the C fragment in the plasmid.