Subsurface hydrological connectivity controls nitrate export flux in a hilly catchment

Subsurface runoff represents the main pathway of nitrate transport in hilly catchments. The magnitude of nitrate export from a source area is closely related to subsurface hydrological connectivity, which refers to the linkage of separate regions of a catchment via subsurface runoff. However, understanding of how subsurface hydrological connectivity regulates catchment nitrate export remains insufficient. This study conducted high-frequency monitoring of shallow groundwater in a hilly catchment over 17 months. Subsurface hydrological connectivity of the catchment over 38 rainfall events was analyzed by combining topography-based upscaling of shallow groundwater and graph theory. Moreover, cross-correlation analysis was used to evaluate the time-series similarity between subsurface hydrological connectivity and nitrate flux during rainfall events. The results showed that the maximum subsurface hydrological connectivity during 32 out of 38 rainfall events was below 0.5. Although subsurface flow paths (i.e., the pathways of lateral subsurface runoff) exhibited clear dynamic extension and contraction during rainfall events, most areas in the catchment did not establish subsurface hydrological connectivity with the stream. The primary pattern of nitrate export was flushing (44.7%), followed by dilution (34.2%), and chemostatic behavior (21.1%). A threshold relationship between subsurface hydrological connectivity and nitrate flux was identified, with nitrate flux rapidly increasing after the subsurface connectivity strength exceeded 0.121. Moreover, the median value of cross-correlation coefficients reached 0.67, which indicated subsurface hydrological connectivity exerts a strong control on nitrate flux. However, this control effect is not constant and it increases with rainfall amount and intensity as a power function. The results of this study provide comprehensive insights into the subsurface hydrological control of catchment nitrate export.

Potentiation of the lateral habenula-ventral tegmental area pathway underlines the susceptibility to depression in mice with chronic pain

Chronic pain often develops severe mood changes such as depression. However, how chronic pain leads to depression remains elusive and the mechanisms determining individuals' responses to depression are largely unexplored. Here we found that depression-like behaviors could only be observed in 67.9% of mice with chronic neuropathic pain, leaving 32.1% of mice with depression resilience. We determined that the spike discharges of the ventral tegmental area (VTA)-projecting lateral habenula (LHb) glutamatergic (Glu) neurons were sequentially increased in sham, resilient and susceptible mice, which consequently inhibited VTA dopaminergic (DA) neurons through a LHbGlu-VTAGABA-VTADA circuit. Furthermore, the LHbGlu-VTADA excitatory inputs were dampened via GABAB receptors in a pre-synaptic manner. Regulation of LHb-VTA pathway largely affected the development of depressive symptoms caused by chronic pain. Our study thus identifies a pivotal role of the LHb-VTA pathway in coupling chronic pain with depression and highlights the activity-dependent contribution of LHbGlu-to-VTADA inhibition in depressive behavioral regulation.

[Analysis of the equity of health human resource allocation for echinococcosis control based on Gini index]

OBJECTIVE

To analyze the current status and evaluate the equity of health human resource allocation for echinococcosis control in Ganzi Tibetan Autonomous Prefecture, Sichuan Province, so as to provide the empirical evidence for optimizing the health human resource allocation for echinococcosis control.

METHODS

A questionnaire survey was performed to collect the numbers of health human sources for echinococcosis control, including health workers, healthcare professionals, certified/assistant physicians and registered nurses, per 1 000 permanent residents, per 1 000 m², per 1 000 residents screened using Bmode ultrasonography and per 1 000 echinococcosis patients in two highly endemic counties and three lowly endemic counties in Ganzi Tibetan Autonomous Prefecture, Sichuan Province from 2016 to 2019. The equity of health human resource allocation for echinococcosis control was evaluated by permanent residents and geographical areas using Lorenz curve and Gini index in Ganzi Tibetan Autonomous Prefecture from 2016 to 2019.

RESULTS

The numbers of health workers, healthcare professionals, certified/assistant physicians and registered nurses per 1 000 permanent residents, per 1 000 permanent residents, per 1 000 m², per 1 000 residents screened using B-mode ultrasonography and per 1 000 echinococcosis patients were 0.99-, 1.06-, 1.78- and 1.88-fold; 3.38-, 3.67-, 6.00- and 6.00-fold; 1.64-, 1.74-, 3.22- and 3.18-fold; and 64.92-, 70.39-, 139.34- and 117.44-fold more in lowly endemic counties than in highly endemic countries in Ganzi Tibetan Autonomous Prefecture, Sichuan Province, 2019. The Gini indexes of health human resource allocation for echinococcosis control were 0.371 to 0.397 by permanent residents and 0.477 to 0.591 by geographical areas in Ganzi Tibetan Autonomous Prefecture from 2016 to 2019, and the Gini indexes (0.469 to 0.730) for allocation of certified/assistant physicians and registered nurses were both higher than those of health workers and healthcare professionals (0.302 to 0.451) by both permanent residents and geographical areas.

CONCLUSIONS

The health human resource allocation for echinococcosis control showed general equity by permanent residents and poor equity by geographical areas in Ganzi Tibetan Autonomous Prefecture, Sichuan Province from 2016 to 2019.

[Correlation of the peripheral serum complement protein levels and cognitive function in first-episode drug-naive patients with schizophrenia]

Objective: To explore the role of peripheral serum complement protein in the pathogenesis of cognitive impairment by analyzing the correlation between peripheral serum levels of complement protein and cognitive function in first-episode drug-naive patients with schizophrenia. Methods: A total of 66 first-episode drug-naive schizophrenics (schizophrenia group) from the Third Affiliated Hospital of Sun Yat-sen University and 88 healthy volunteers (control group) were enrolled. Peripheral serum levels of complements (C3, C4 and CH50) were separately examined by liposome immunoassay and turbidimetric inhibition immunoassay. The MATRICS Consensus Cognitive Battery (MCCB) was used to assess the cognitive function. Results: Peripheral serum levels of C4, but not C3 and CH50, were significantly lower in patients with schizophrenia [0.20(0.16, 0.25) g/L] than those in the control group [0.23 (0.19, 0.27) g/L] (P<0.05). Moreover the peripheral serum levels of C3, C4 and CH50 were positively correlated with MCCB verbal fluency (r=0.258, r=0.283 and r=0.330, all P<0.05), and the peripheral serum levels of CH50 were negatively correlated with attention and alertness (r=-0.257, P<0.05). Conclusion: The decrease of peripheral serum complement C4 protein levels may be involved in the mechamism of cognitive impairment in schizophrenia.

Effects of chlorogenic acid-enriched extract from Eucommia ulmoides leaf on performance, meat quality, oxidative stability, and fatty acid profile of meat in heat-stressed broilers

To investigate the effects of chlorogenic acid-enriched extract (CGAE) from Eucommia ulmoides leaf on performance, meat quality, oxidative stability, and fatty acid profile of breast meat in heat-stressed broilers, 400 28-day-old male Ross 308 broilers were randomly assigned into 4 groups with 10 replicates per group (10 broilers per replicate). Broilers in the normal group (NOR) were kept at 22 ± 2°C (24 h/D) and fed the basal diet, and the other 3 groups were treated with cyclic heat (34 ± 2°C from 08:00 to 18:00 and 22 ± 2°C from 18:00 to 08:00) and fed the basal diet supplemented with 0 (HT), 500 (CGAE500), and 1,000 mg (CGAE1000) mg of CGAE/kg of diet. The experiment lasted for 14 D. Compared with the HT group, broilers in the NOR and CGAE1000 groups had a higher average daily gain and a lower feed conversion ratio (P < 0.05). CGAE supplementation at 1,000 mg/kg increased pH24 value, a* value and total superoxide dismutase activity and reduced drip loss, cooking loss, L* value and the contents of malondialdehyde and carbonyl in breast meat of heat-stressed broilers (P < 0.05). Broilers in the HT group showed lower mRNA levels of nuclear factor erythroid 2-related factor 2 (P < 0.001), superoxide dismutase (P = 0.004), and catalase (P < 0.001) in breast meat compared with the other groups. CGAE supplementation at 1,000 mg/kg reduced the stearic acid and saturated fatty acids (SFA) contents and increased the dihomo-γ-linolenic acid, linoleic acid, linolenic acid, eicosapentaenoic acid, polyunsaturated fatty acids (PUFA), and n-6 PUFA contents and PUFA:SFA ratio in breast meat of heat-stressed broilers (P < 0.05). In conclusion, CGAE supplementation at 1,000 mg/kg could alleviate the adverse effects of heat stress on growth performance and meat quality and improve oxidative stability and fatty acid profile of breast meat in heat-stressed broilers.

[Survey of the depressive disorders prevalence and related risk factors among male new drug users in certain drug rehabilitation center of Changsha city]

Objective: To understand the depressive disorders prevalence and related risk factors among new drug users in a male drug rehabilitation center. Methods: The cross-sectional study was used. A total of 250 new drug users from a male drug rehabilitation center were recruited during March, 2017. The drug users who only use new type of drugs single or use traditional drugs at the same time were collected as the new drug users. Their general information and drug-related information were collected by self-made questionnaire, and depressive disorders and sleep quality information were collected by the self-reported Patient Health Questionnaire-9 (PHQ-9) and the self-reported Pittsburgh Sleep Quality Index Questionnaire respectively. Logistic regression test was used to establish associations between variables. Results: Of all 250 drug users, the mean age (P(25), P(75)) was 30 (26, 35) years old, and 32.8% (82) had the depressive disorders. The individuals taking drug dose over 0.4 g daily before entering drug rehabilitation center had significantly more risk of the depressive disorders for 3.18 (1.71-5.90) than those not over 0.4 g daily.The individuals who bad sleep quality had significantly more risk of the depressive disorders for 6.07 (95%CI:3.31-11.12) than those had good sleep quality.The individuals who were depressive patients before the first drug use for 2.39 (95%CI: 1.12-5.10) than those were not depressive patients before the first drug use. Conclusion: There were a high rate of the depressive disorders among new drug users in the rehabilitation center; In addition, several risk factors including the individuals taking drug dose over 0.4 g daily and bad sleep quality, history of the depressive disorders were negatively associated with depressive disorders.

Large-scale screening and characterisation of Lemna aequinoctialis and Spirodela polyrhiza strains for starch production

Duckweed is considered a promising feedstock for bioethanol production due to its high biomass and starch production. Selection of duckweed strains with high starch accumulation is essential for application of duckweeds to bioethanol production. Geographic differentiation had a large influence on genetic diversity of duckweeds. Biomass production, starch content and starch amount in geographically isolated strains of 20 Lemna aequinoctialis and Spirodela polyrhiza were calculated to evaluate their potential for bioethanol production. The influence of different collection time, culture medium and NaCl concentration on starch accumulation of the best strains were analysed. The results showed that biomass production, starch content and starch production of duckweeds demonstrated clonal dependency. The best strain was L. aequinoctialis 6000, with biomass production of 15.38 ± 1.47 g m^-2 , starch content of 28.68 ± 1.10% and starch production of 4.39 ± 0.25 g m^-2 . Furthermore, starch content of L. aequinoctialis 6000 was highest after 8 h of light, tap water was the best medium for starch induction, and NaCl did not induce starch accumulation. This study suggests duckweed biomass production and starch production demonstrate clonal dependency, indicating that extensive clonal comparisons will be required to identify the most suitable isolates for duckweed selective breeding for bioethanol.

Effects of chestnut tannins on intestinal morphology, barrier function, pro-inflammatory cytokine expression, microflora and antioxidant capacity in heat-stressed broilers

A study was conducted to evaluate the effects of chestnut tannins (CT) on intestinal morphology, barrier function, pro-inflammatory cytokine expression, microflora and antioxidant capacity in heat-stressed broilers. Four hundred 28-day-old male Ross 308 broilers were randomly assigned into four groups, with 10 replicates per group and 10 broilers per replicate. The broilers in the normal (NOR) group were kept at 22 ± 1°C and fed the basal diet, and each of the other three groups were treated with cyclic heat (33 ± 1°C from 0800 to 1800 and 22 ± 1°C from 1800 to 0800) and fed the basal diet with 0 (HT), 1 (CT1) or 2 (CT2) g of CT/kg of diet. The experiment lasted for 14 days. Compared with the HT group, broilers in the NOR and CT2 groups had higher (p < .05) average daily gain and villus height in the jejunum and lower serum d-lactate (p < .001) and diamine oxidase (p < .01) levels. The addition of 2 g CT/kg of diet increased the total antioxidant capacity (p < .001) and superoxide dismutase activities (p < .05) and zonula occludens-1 mRNA expression level (p < .05) and decreased the malondialdehyde concentration (p < .01) and mRNA expression levels of interleukin-6 (p < .001) and nuclear factor kappa B (p < .001) in the jejunal mucosa of heat-stressed broilers. The populations of Escherichia coli and Clostridium in the jejunum (p < .01) and caecum (p < .05) of broilers in the HT group were higher than those in the NOR and CT2 groups. In conclusion, the addition of 2 g CT/kg of diet seemed to be a feasible means of alleviating the negative effects of heat stress on the growth performance and intestinal function of broilers.

Effect of low-dose cyclophosphamide on endoplasmic reticulum stress and inflammatory reaction of acute renal ischemia reperfusion injury

OBJECTIVE

To explore the effect of low-dose cyclophosphamide (CP) on endoplasmic reticulum stress (ERS) and inflammatory reaction of acute renal ischemia reperfusion injury (IRI), providing new ideas for clinical treatment.

MATERIALS AND METHODS

Sixty healthy adult male mice were selected and divided randomly into sham operation group (n = 20), IRI group (n = 20 cases), and the experimental group (n = 20 cases). Mice in the experimental group were pretreated with low-dose CP and acute IRI model construction. Intercellular adhesion molecule-1 (ICAM-1) immunohistochemical staining was conducted after the 24h and the detection of CHOP protein by Western blot method. Postoperative 3h and 7 day survival rate, the results of ICAM-1 immunohistochemistry staining and the gray values of C/EBP homologous protein (CHOP) of mice were compared between the three groups.

RESULTS

The survival rates of mice in the IRI group and the experimental group after operation were decreased significantly (p < 0.05). However, the survival rates of mice in the experimental group were higher than that in the IRI group. The differences were significant (p < 0.05). The expression of ICAM-1 was significantly reduced (p < 0.05). The difference was statistically significant. The expression of ICAM-1 was significantly reduced (p < 0.05). The gray values of mice in the IRI group and the experimental group were significantly increased. The difference was statistically significant (p < 0.05). And the gray value in the IRI group increased more than that of the experimental group. The difference was statistically significant (p < 0.05).

CONCLUSIONS

The pretreatment with low-dose CP for mice with acute renal IRI can reduce effectively the ERS and inflammation, which reduces kidney damage for mice and have good effect on prolonging its life. It provides a good way for the guidance of clinical research.

Simultaneous optical parametric oscillation and intracavity second-harmonic generation based on a hexagonally poled lithium tantalate

Simultaneous optical parametric oscillation and intracavity second-harmonic generation based on a hexagonally poled lithium tantalate is reported. Both the optical parametric oscillation and the cascaded noncollinear second-order harmonic generation processes reach a high efficiency. A variety of possible self-doubling optical parametric oscillation processes indicate this hexagonally poled lithium tantalate has potential applications as a compact multi-wavelength light source.

Transforming spatial entanglement using a domain-engineering technique

We study the spatial correlation of a two-photon entangled state produced in a multistripe periodically poled LiTaO3 crystal by spontaneous parametric down-conversion. The far-field diffraction-interference experiments reveal that the transverse modulation of domain patterns transforms the spatial mode function of the two-photon state. This result offers an approach to prepare a novel type of two-photon state with a unique spatial entanglement by using a domain-engineering technique.

Frequency self-doubling optical parametric amplification: noncollinear red-green-blue light-source generation based on a hexagonally poled lithium tantalate

Simultaneous generation of noncollinear red, green, and blue light from a single hexagonally poled lithium tantalate is reported. It results from the frequency self-doubling optical parametric amplification process, a process of second-order harmonic generation cascaded optical parametric amplification in a single-pass setup. The temperature and spectrum detuning characters of each cascaded quasi-phase-matching process are studied. This unique red-green-blue light source has potential applications in laser display and other laser industries.

Three-dimensional quantitative structure activity relationship (3D-QSAR) analysis for in vitro toxicity of chlorophenols to HepG2 cells

In the present paper, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were applied to investigate two 3D-QSAR models for the cytotoxicity of chlorophenols. These models have evaluated the intensity of chlorophenols' toxicity on HepG2 cells in vitro. The CoMFA model has both high consistency and predictability. The contribution of the electrostatic field to biological activity is greater than that of the steric field. The CoMSIA model used in this study includes two fields, one is hydrophobic field, and the other is electrostatic field. The relative contribution of them is 0.789:0.211. Consisted with the CoMFA model, the CoMSIA electrostatic filed also plays a dominant role. The CoMFA and CoMSIA contour maps significantly elucidated that the electrostatic field is more important than the other fields and might be one of the reasons resulting in potential reactive mechanism involved in cell proliferation inhibition.

Process for degradation of nitrobenzene: combining electron beam irradiation with biotransformation

Electron beam irradiations of aqueous solutions containing 15-30 mg/L of nitrobenzene at 60 kGy dose removed 78% of the contaminant. Three mononitrophenols were detected as by-products of electron beam treatment of nitrobenzene. A mixed culture enriched on a mixture of 2-, 3-, and 4-nitrophenol degraded both the residual nitrobenzene and the nitrophenol products. Percentage removal of nitrobenzene increased with increasing electron beam dose. This observation led to the conceptual design of a two-stage electron beam microbial process for degradation of nitrobenzene. Three groups of pure isolates were characterized from the mixed culture based on their abilities to grow on cor- responding nitrophenol substrates: Group A, 2NP(-)3NP(-)4NP(+); Group B, 2NP(+)3NP(+)4NP(-); and Group C, 2NP(-)3NP(+)4NP(-). Bacteria that grew on 3-NP transformed nitrobenzene into ammonia in the electron beam-treated nitrobenzene samples.

Substrate selectivity of a 3-nitrophenol-induced metabolic system in Pseudomonas putida 2NP8 transforming nitroaromatic compounds into ammonia under aerobic conditions

The 3-nitrophenol-induced enzyme system in cells of Pseudomonas putida 2NP8 manifested a wide substrate range in transforming nitroaromatic compounds through to ammonia production. All of the 30 mono- or dinitroaromatic substrates except 4-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, 3-nitroaniline, 2-nitrobenzoic acid, and 2-nitrofuran were quickly transformed. Ammonia production from most nitroaromatic substrates appeared to be stoichiometric.

Cometabolic biotransformation of nitrobenzene by 3-nitrophenol degrading Pseudomonas putida 2NP8

A strain of Pseudomonas putida (2NP8) capable of growing on both 2-nitrophenol and 3-nitrophenol, but not on nitrobenzene (NB), was isolated from municipal activated sludge. 2-Nitrophenol was degraded by this strain with production of nitrite. Degradation of 3-nitrophenol resulted in the formation of ammonia. Cells grown on 2-nitrophenol did not degrade nitrobenzene. A specific nitrobenzene degradation activity was induced by 3-nitrophenol. Ammonia, nitrosobenzene, and hydroxylaminobenzene have been detected as metabolites of nitrobenzene degradation by cells grown in the presence of 3-nitrophenol. These results indicated a NB cometabolism mediated by 3-nitrophenol nitroreductase.

Biotransformation of hydroxylaminobenzene and aminophenol by Pseudomonas putida 2NP8 cells grown in the presence of 3-nitrophenol

Biotransformation products of hydroxylaminobenzene and aminophenol produced by 3-nitrophenol-grown cells of Pseudomonas putida 2NP8, a strain grown on 2- and 3-nitrophenol, were characterized. Ammonia, 2-aminophenol, 4-aminophenol, 4-benzoquinone, N-acetyl-4-aminophenol, N-acetyl-2-aminophenol, 2-aminophenoxazine-3-one, 4-hydroquinone, and catechol were produced from hydroxylaminobenzene. Ammonia, N-acetyl-2-aminophenol, and 2-aminophenoxazine-3-one were produced from 2-aminophenol. All of these metabolites were also found in the nitrobenzene transformation medium, and this demonstrated that they were metabolites of nitrobenzene transformation via hydroxylaminobenzene. Production of 2-aminophenoxazine-3-one indicated that oxidation of 2-aminophenol via imine occurred. Rapid release of ammonia from 2-aminophenol transformation indicated that hydrolysis of the imine intermediate was the dominant reaction. The low level of 2-aminophenoxazine-3-one indicated that formation of this compound was probably due to a spontaneous reaction accompanying oxidation of 2-aminophenol via imine. 4-Hydroquinone and catechol were reduction products of 2- and 4-benzoquinones. Based on these transformation products, we propose a new ammonia release pathway via oxidation of aminophenol to benzoquinone monoimine and subsequent hydrolysis for transformation of nitroaromatic compounds by 3-nitrophenol-grown cells of P. putida 2NP8. We propose a parallel mechanism for 3-nitrophenol degradation in P. putida 2NP8, in which all of the possible intermediates are postulated.

Microbial degradation of nitrobenzene and mono-nitrophenol by bacteria enriched from municipal activated sludge

Using a mixture of three mono nitrophenols as sole carbon, nitrogen and energy sources, mixed cultures were enriched from municipal activated sludge to degrade both nitrophenols and nitrobenzene. Bacterial growth and degradation rate could be increased by supplementing the medium with 0.1% YE. Microorganisms were isolated from the nitrophenols enrichment, and they were identified as strains of Comamonas testosteroni and Acidovorax delafieldii. These strains showed broad degradation ability toward nitrophenols and nitrobenzene.

Impaired lung branching morphogenesis in the absence of functional EGF receptor

The mammalian lung develops through branching morphogenesis which is controlled by growth factors, hormones, and extracellular matrix proteins. We have evaluated the role of EGF-receptor signaling in lung morphogenesis by analyzing the developmental phenotype of lungs in mice with an inactivated the EGF-receptor gene both in vivo and in organ culture. Neonatal EGF-receptor-deficient mice often show evidence of lung immaturity which can result in visible respiratory distress. The lungs of these mutant mice had impaired branching and deficient alveolization and septation, resulting in a 50% reduction in alveolar volume and, thus, a markedly reduced surface for gas exchange. The EGF-receptor inactivation also resulted in type II pneumocyte immaturity, which was apparent from their increased glycogen content and a reduced number of lamellar bodies. The defective branching was already evident at Day 12 of embryonic development. When explants of embryonic lungs from Day 12 embryos were cultured under defined conditions, the branching defect in EGF-receptor-deficient lungs was even more pronounced, with only half as many terminal buds as normal lungs. EGF treatment stimulated the expression of surfactant protein C and thyroid transcription factor-1 in cultured normal lungs, but not in EGF-receptor-deficient lungs, suggesting that EGF-receptor signaling regulates the expression of these marker genes during type II pneumocyte maturation. Taken together, our data indicate that signal transduction through the EGF receptor plays a major role in lung development and that its inactivation leads to a respiratory distress-like syndrome.

A molecular model of braid-like DNA structure

The three-dimensional molecular models of DNA triple helices and triple-stranded brain-like structure were built up by molecular architecture, and their structural features and energy decomposition were examined. The results showed: (i) The base triplet is the element forming braid-like and triple helix DNA; (ii) Under specified conditions, DNA could form the triplet-stranded braid-like structure; (iii) DNA stability of the braid-like structure is less than that of the triple helix structure.

[Comparative pathologic study on the peri-ulcer mucosal lesion around benign and malignant gastric ulcer]

3441 peri-ulcerous mucosal lesions around benign and malignant gastric ulcers (1479 benign gastric ulcers, 421 cancerous degeneration of benign ulcers and 1541 ulcerative carcinomas) were studied comparatively. It was found that the ulcer of cancerous degeneration of benign ulcer was small and the epithelial regeneration at the ulcer's edge and fusion of the muscularis mucosa with the muscularis propria were very common. The cancerous tissue, extending down to the submucosa, was found at the margin but not at the base of the ulcer. Lymph node metastasis was rare. Therefore, the cancerous degeneration of ulcer was most likely an early carcinoma. These findings conform well with Hauser's criteria. Chronic atrophic gastritis intestinal metaplasia (IIb and type II), moderate and severe dysplasia were more commonly observed in cancerous degeneration of ulcers than in benign peptic ulcers or ulcerative carcinoma. These results suggest that multiple biopsies should be taken from the edge of chronic ulcers.

Formation in vitro of the pTP-dCMP initiation complex of human adenovirus type 12

We report the covalent addition of [32P]dCMP to a protein from group A adenovirus 12 (Ad12)-infected human (KB) cells in vitro, using crude extracts. Synthesis of the 60K protein-dCMP complex required a DNA template containing a terminally located adenovirus replication origin; the protein-dCMP bond was alkali-labile but acid-stable. We therefore conclude that this product is the Ad12 terminal protein precursor (pTP)-dCMP initiation complex for DNA replication. Synthesis of Ad12 pTP-dCMP was specific for dCTP but was stimulated by dATP. In contrast to Ad2, the Ad12 initiation reaction required ATP. Antipeptide antiserum targeted to Ad DNA polymerase inhibited Ad12 pTP-dCMP synthesis in vitro, providing evidence that Ad DNA polymerase catalyse dCMP addition to pTP during initiation.