A deep sleep in coal beds Deep below the ocean floor, microorganisms from forest soils continue to thrive. Inagaki et al. analyzed the microbial communities in several drill cores off the coast of Japan, some sampling more than 2 km below the seafloor (see the Perspective by Huber). Although cell counts decreased with depth, deep coal beds harbored active communities of methanogenic bacteria. These communities were more similar to those found in forest soils than in other deep marine sediments. Science , this issue p. 420 ; see also p. 376

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Salivary duct carcinoma (cribriform salivary carcinoma of the excretory ducts [CSCED]) is an uncommon malignant tumor which occurs predominantly in men (83% in this series; mean age, 61 years) and most often in the parotid gland (92% in this series). The outcome is unfavorable for most patients; of 11 of 12 patients with follow-up, 45% had local recurrence, 54% had distant metastasis, and 45% were dead of disease within 10 years of diagnosis (mean, 3 years). Metastases to lymph nodes were common (72%). Immunohistochemical studies on paraffin-embedded tissue revealed that most tumors reacted with antibodies known to mark adenocarcinoma: B72.3 (11 of 11) and Lewis Y (ten of ten). High and low molecular weight cytokeratins were present in most tumors (nine of ten and seven of nine cases, respectively), supporting the concept that these adenocarcinomas were of ductal origin. Parotid ducts adjacent to CSCED expressed B72.3 in six of nine cases studied, but parotid ducts from normal tissue (adjacent to benign mixed tumors or enlarged periparotid lymph nodes) rarely expressed this marker (one of 17 cases). The detection of B72.3 diffusely in parotid ducts, especially those with atypia, may imply the presence of malignant tumor nearby, which could be useful in evaluating limited tissue from the parotid. However, further studies are necessary to confirm the significance of this finding.

Microorganisms in marine subsurface sediments substantially contribute to global biomass. Sediments warmer than 40°C account for roughly half the marine sediment volume, but the processes mediated by microbial populations in these hard-to-access environments are poorly understood. We investigated microbial life in up to 1.2-kilometer-deep and up to 120°C hot sediments in the Nankai Trough subduction zone. Above 45°C, concentrations of vegetative cells drop two orders of magnitude and endospores become more than 6000 times more abundant than vegetative cells. Methane is biologically produced and oxidized until sediments reach 80° to 85°C. In 100° to 120°C sediments, isotopic evidence and increased cell concentrations demonstrate the activity of acetate-degrading hyperthermophiles. Above 45°C, populated zones alternate with zones up to 192 meters thick where microbes were undetectable.

To further characterize diurnal changes in the rhythm in adrenal responsiveness to ACTH, we have measured ACTH distribution volume, MCR, and t 1/2. These do not change between morning and evening in groups of untreated, dexamethasone-pretreated, or hypophysectomized female rats. To characterize the nature of the change in adrenal responsiveness to ACTH, dexamethasone-pretreated rats were infused for 2 h with a variety of doses of ACTH in the morning and evening. The adrenal response to an infusion rate of ACTH that maximally stimulated the adrenals (200 pg/100 g BW.min) was the same in the morning and evening, showing that adrenal capacity does not change. However, infusion of ACTH at lower rates (50-100 pg/100 g BW.min) revealed that the slope of the steroid response curve increased between morning and evening, demonstrating a diurnal change in adrenal sensitivity to ACTH. These results together with previous data showing that the magnitude and time course of the adrenal cAMP response to ACTH changes diurnally strongly suggest that ACTH receptor affinity or coupling with adenylate cyclase changes diurnally. In other experiments, plasma ACTH and corticosterone levels were determined in groups of young and adult male and adult female untreated rats killed at 4-h intervals around the clock. Peak sensitivity to ACTH was found at lights-out, and trough sensitivity was found at lights-on, suggesting that the experimentally demonstrated rhythm occurs normally.