In streptomycetes, autoregulators are important signaling compounds that trigger secondary metabolism, and they are regarded as hormones based on their extremely low effective concentrations (nM) and the involvement of specific receptor proteins. Our previous distribution study revealed that butenolide-type hormones, including avenolide, are a general class of signaling molecules in streptomycetes and that strain J1074 may produce butenolide-type hormones. Here, we describe metabolite profiling of a disruptant of the gene, which encodes a key biosynthetic enzyme for butenolide-type hormones, and identify four butenolide compounds from J1074 that show avenolide activity. The compounds structurally resemble avenolide and show different levels of avenolide activity. A dual-culture assay with imaging mass spectrometry (IMS) analysis for metabolic profiling demonstrated that the butenolide compounds of J1074 stimulate avermectin production in another species, , illustrating the complex chemical interactions through interspecies signals in streptomycetes. Microorganisms produce external and internal signaling molecules to control their complex physiological traits. In actinomycetes, hormones are low-molecular-weight signals that are key to our understanding of the regulatory mechanisms of secondary metabolism. This study reveals that acyl coenzyme A (acyl-CoA) oxidase is a common and essential biosynthetic enzyme for butenolide-type hormones. Moreover, the diffusible butenolide compounds from a donor strain were recognized by the recipient strain of a different species, resulting in the initiation of secondary metabolism in the recipient. This is an interesting report on the chemical interaction between two different streptomycetes via hormones. Information on the metabolite network may provide useful hints not only to clarification of the regulatory mechanism of secondary metabolism, but also to understanding of the chemical communication among streptomycetes to control their physiological traits.

Nasopharyngeal carcinoma (NPC) is amongst the most common malignancies of head and neck cancers. Most patients are admitted to the hospital with advanced disease. NPC has a tendency toward early metastatic spread to cervical lymph nodes, and levels II and III are most commonly involved. A few reports have indicated specific metastatic sites of nasopharyngeal cancer, including lymph node metastasis and distant metastasis. Evidence of histopathology and immunohistochemistry is required to prove NPC origin. In many cases, surgery can be performed to obtain accurate evidence of the pathology. However, surgery can also affect the overall treatment plan and strategy for NPC and should be considered in the specific circumstances of the disease. Multidisciplinary consultation is required for these uncommonly specific metastases. Paying attention to the specific lymph node metastasis sites of NPC plays an important role in accurately diagnosing the stage, thereby giving an appropriate treatment strategy. It is also important in determining radiotherapy volumes because radiotherapy is the standard therapy for this disease. Herein, we are reporting 2 cases of NPC with clinical metastasis to unusual lymph node sites such as the parotid salivary gland and the cheek. Histological analyses from the resected specimens confirmed its nasopharyngeal origin. Lymph node metastases in the parotid gland and the cheek are unusual. In diagnosis and follow-up, it is necessary to evaluate carefully to make an accurate diagnosis and appropriate treatment plans for patients as well as early detect recurrent metastases at uncommon sites of lymph nodes.

<p>In most productive agricultural soils, organic matter (OM) makes up a small percentage (3-6%) but plays a vital role in biogeochemical processes, particularly nutrient availability and soil structure stability as influenced by cation exchange processes. The loss of soil OM is one of the most severe threats to much of the World's arable areas. Thus, OM application (e.g. biosolids, livestock manure, and compost) is widely recommended due to its cost-effectiveness, and high macro- and micro-nutrient contents. In this regard, the intrinsic properties of soil OM in conjunction with cation exchange processes have not been thoroughly addressed. Therefore, it is essential to quantify cation exchange in biosolids and biosolid-amended soils, specifically, the competitive cation exchange process. The main objective of this study was to evaluate cation exchange equilibria on biosolid-derived compost in binary cation solutions. The target cations were NH<sub>4</sub><sup>+</sup>, K<sup>+</sup>, Na<sup>+</sup>, Ca<sup>2+</sup>, and Mg<sup>2+</sup>, which are relevant to plant nutrient availability and the efficiency of remediation strategies for saline and sodic soils. Here, binary exchange isotherm experiments were conducted in which the biosolid was pre-saturated with Ca<sup>2+</sup>. The selectivity coefficient was calculated from the measured exchange isotherms. The results showed that the shape of the exchange isotherm curves and the amount of cations exchanged varied in different binary systems. The biosolid characteristics, as well as the preference of particular cations to the biosolid, will be presented and discussed.</p><p>Keywords: soil organic matter, biosolid, cation exchange, selectivity coefficient.</p>