Antifouling activity of synthetic polymer gels against cyprids of the barnacle (Balanus amphitrite) in vitro.

Barnacle (Balanus amphitrite) settlement on synthetic hydrogels with various chemical structures was tested in laboratory assays. The results demonstrated that cyprids settle less or not at all on hydrogels and PDMS elastomer compared with the polystyrene control. The low settlement on gels is most likely due to the 'easy release' of initially attached cyprids from the gel surfaces. This low adhesion of cyprids is independent of surface hydrophilicity or hydrophobicity, and of surface charge. The results also revealed that hydrogels can be categorized into two groups. One group showed an extremely strong antifouling (AF) performance that was independent of the elasticity (E) or swelling degree (q) of the gels. The second group showed relatively less strong AF performance that was E- or q-dependent. In the latter case, E, rather than the q, may be the more important factor for cyprid settlement.

Isocyano compounds as non-toxic antifoulants.

The marine sponge Acanthella cavernosa and nudibranchs of the family Phyllidiidae contain isocyanoterpenoids and their related compounds that show potent antifouling activity against cypris larvae of the barnacle Balanus amphitrite, while their toxicity to cyprids is weak. To develop non-toxic antifoulants based on isocyanoterpenoids, especially 3-isocyanotheonellin, a total of 36 isocyano compounds have been synthesized. They were evaluated by both antifouling activity and toxicity toward B. amphitrite cyprids, which led some insight into the structure-activity relationships. Since linear alkyl isocyanides showed antifouling activity at nontoxic concentrations, a large amount of 1,1-dimethyl-10-undecyl isocyanide was synthesized, incorporated into paints, and tested for antifouling activity in the field with promising results. Therefore, isocyano compounds were considered as candidate non-toxic antifouling agents.

Inhibitors of platelet lipoxygenase from Ponkan fruit.

An activity-guided separation for inhibitors of rat platelet 12-lipoxygenase led to the isolation of two compounds, 4-O-feruloyl-5-O-caffeoylquinic acid (IC50; 5.5 microM) and methyl 4-O-feruloyl-5-O-caffeoylquinate (IC50; 1.9 microM) from the peel of Ponkan fruit (Citrus reticulata). The complete structure of each phenolic ester was determined by NMR spectroscopy [1H and 13C NMR spectra, 1H-1H correlation spectroscopy (COSY), 1H-detected heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond connectivity (HMBC) spectroscopies] and other spectral methods.

Directed deletions in the aflatoxin biosynthesis gene homolog cluster of Aspergillus oryzae.

To investigate the structure of the aflatoxin gene cluster in Aspergillus oryzae, 39 strains belonging to this species were examined for the existence of pksA, fas1A, aflR and vbs, and the results compared with those for ver-1 obtained previously. These five genes are involved in aflatoxin biosynthesis in Aspergillus parasiticus. The strains examined were categorized into three groups; group 1, having the five homologs; 2, having ver-1 and vbs; and 3, having vbs homologs. Long-PCR analysis of the regions between the five homologs in A. oryzae IFO 4135, coupled with Southern-hybridization analysis, shows that those homologs are clustered with the same arrangement as in A. parasiticus. These results suggest that directed deletions of the cluster occur in A. oryzae strains. The possible breakpoints of the deletions in the strains of group 2 and 3 were estimated.

Transcript of a homolog of aflR, a regulatory gene for aflatoxin synthesis in Aspergillus parasiticus, was not detected in Aspergillus oryzae strains.

Some strains of Aspergillus oryzae were shown to have homologs of aflR, a regulatory gene for aflatoxin synthesis in Aspergillus parasiticus. Transcription of an aflR homolog was examined in six strains of A. oryzae having the homologs, using polymerase chain reaction (PCR) coupled with reverse transcription. No PCR product was obtained when the RNA prepared from the A. oryzae strains cultivated under aflatoxin-producing condition was used as template for amplification of the aflR cDNA. By contrast, a PCR product of the expected size was obtained with RNA from A. parasiticus NIAH-26 processed by the same procedure. From genomic DNA of these strains, PCR products of the same size as above were obtained. Possible degradation of the aflR mRNA in the RNA preparation of the A. oryzae strains was negligible, because the calmodulin transcript was detected by PCR from the same RNA samples. Thus, the aflR homologs in the non-aflatoxigenic A. oryzae strains examined are not expressed even under aflatoxin-producing condition.

Aspergillus oryzae with and without a homolog of aflatoxin biosynthetic gene ver-1.

Part of the nucleotide sequence of the ver-1 homolog in each of two strains of Aspergillus oryzae, Aspergillus sojae, and Aspergillus flavus were compared with two homologs in Aspergillus parasiticus. The homologs in A. oryzae and A. sojae (non-aflatoxin-producers) exhibited an extremely high degree (93.8-99.8% for A. oryzae, and 96.0-99.5% for A. sojae) of sequence identify with that of A. flavus and A. parasiticus. No two strains within the same species, except A. sojae, were identical. No sequence fingerprint was found to distinguish between A. oryzae and A. flavus, or between A. sojae and A. parasiticus. The predicted partial amino acid sequences (181 amino acids) of the ver-1 homologs had at most two amino acid changes relative to A. parasiticus SYS-4 ver-1. Transcripts of ver-1 homologs in the strains of A. oryzae and A. sojae examined were not detected by the polymerase chain reaction coupled with reverse transcription. By Southern analysis, a total of 46 strains of A. oryzae were examined for the presence of the ver-1 homolog. The homolog was detected in 38 strains, but not in 8 strains. Morphologically, strains with and without the ver-1 homolog were indistinguishable. Thus, A. oryzae contains strains with and without a homolog of the aflatoxin biosynthetic gene ver-1.

Thiomycalolides: new cytotoxic trisoxazole-containing macrolides isolated from a marine sponge Mycale sp.

Two new cytotoxic trisoxazole macrolides, thiomycalolides A (2) and B (3), have been isolated from a marine sponge Mycale sp. The structures were determined to be glutathione adducts of mycalolides A and B by interpretation of spectral data and chemical transformation. Thiomycalolides A and B are highly cytotoxic against P388 murine leukemia cells.

Homolog of a-factor receptor gene in Saccharomyces exiguus.

Homologs of Saccharomyces cerevisiae STE3, a-factor receptor gene were detected from S. exiguus NFRI 3539 by low stringency Southern hybridization. This strain might have at least two types of homolog. One of these homologs, designated as e-STE3 was cloned. Its nucleotide sequence revealed 60% identity to STE3. The putative protein coding region consisted of 453 amino acid residues. The amino acid sequence identity between STE3 and e-STE3 was 62% and that of the N-terminal 303 amino acid residues considered to be the pheromone binding domain was 79%.

Decreased signal intensity of cerebral cortex on T2-weighted MR images.

To define the frequency of decreased signal intensity (DSI) in cerebral cortex on T2-weighted images relative to aging and to the incidence of identifying white matter pathology, T2-weighted MR brain images of 906 patients consecutively examined between July 1989 and June 1991 were reviewed. MR images of cerebral cortex were divided into five areas: frontal lobe (F), pre- and postcentral gyri (C), parietal lobe (P), occipital lobe (O) and temporal lobe (T). Each area was separately and independently evaluated for the presence or absence of DSI. The frequency of DSI in each area was plotted against patients' ages. The severity of leukoaraiosis was evaluated in relation with DSI in each cortical area. Patients with DSI in area F numbered 61 (5.7%), in area C 236 (26.0%), in area P 174 (15.9%), in area O 428 (47.2%), and in area T 10 (1.1%). The number of patients with DSI in each area increased with age. The greater the severity of leukoaraiosis, the greater the chance of finding DSI of the cerebral cortex. The incidence of DSI in the cerebral cortex increased with the patient's age as well as with the severity of co-existent white matter pathology.

Adrenal adenomas: characteristic hyperintense rim sign on fat-saturated spin-echo MR images.

PURPOSE: To determine whether adrenal adenomas can be differentiated from metastases on fat-saturated magnetic resonance (MR) images. MATERIALS AND METHODS: Twenty-eight adrenal adenomas and 20 metastatic lesions were imaged at 1.5 T by means of fat-saturated T1- and T2-weighted and gadolinium-enhanced T1-weighted sequences. The authors evaluated visually whether structures of high signal intensity (hyperintense rim sign) could be observed in the outer margin of the adrenal masses. RESULTS: Twenty-six of 28 adrenal adenomas revealed the hyperintense rim sign on at least one kind of fat-saturated image, compared with only one of 20 metastases. The sensitivity of the hyperintense rim sign as suggestive of adrenal adenoma was 92%, specificity was 95%, and overall accuracy was 94%. CONCLUSION: The hyperintense rim sign is characteristic of adrenal adenomas. Thus, adrenal adenomas can be differentiated from metastases by means of this new imaging sign on fat-saturated MR images.

Septa in the liver of patients with chronic hepatic schistosomiasis japonica: MR appearance.

OBJECTIVE: Chronic hepatic schistosomiasis japonica is a disorder characterized by broad fibrous septa in the liver. The ability to recognize these septa on MR images might enable distinction of this lesion from other cirrhotic disorders. The purpose of this study was to analyze the MR appearance of these septa. MATERIALS AND METHODS: MR images of 18 patients who had typical calcifications of hepatic septa on CT scans were reviewed. The diagnosis was proved by biopsy in six patients. In the remaining 12, stool examinations were positive for schistosomiasis. T1-weighted MR images and T2-weighted and intermediate (long repetition time and short echo time) MR images acquired with the use of gradient-moment nulling were obtained in all 18 patients. In eight of 18 patients, additional T2-weighted and intermediate images were obtained without gradient-moment nulling. Fifteen patients had contrast-enhanced T1-weighted images. The presence of abnormal MR signal and its intensity at sites corresponding to the septa seen on CT scans were studied. RESULTS: MR images showed the septa as linear abnormalities frequently seen in the subdiaphragmatic portion of the right lobe of the liver. On T1-weighted images, septa had low signal intensity and were identified in nine of 18 patients. On T2-weighted images obtained with gradient-moment nulling, septa had high signal intensity and were seen in 13 of 18 patients. On T2-weighted images obtained without gradient-moment nulling, the septa had primarily low signal intensity and were seen in five of eight patients. On intermediate MR images obtained with gradient-moment nulling, the septa had primarily high signal intensity and were seen in nine of 18 patients. On intermediate images obtained without gradient-moment nulling, the septa had primarily low signal intensity and were seen in four of eight patients. In nine of 15 patients, septa were visualized as high-signal-intensity lesions on contrast-enhanced T1-weighted images. In 14 of 18 patients, the septa were detected in one or more sequences. CONCLUSION: Our experience suggests that MR imaging in patients with chronic schistosomiasis of the liver depicts the morphologic features of hepatic septa. MR signal characteristics of septa are not unique, but use of gradient-moment nulling alters the signal intensity of septa, similar to that of blood vessels, on intermediate and T2-weighted images.

Amyotrophic lateral sclerosis: T2 shortening in motor cortex at MR imaging.

PURPOSE: To determine whether decreased signal intensity of the motor cortex (T2 shortening) at magnetic resonance (MR) imaging is a useful finding for supporting the diagnosis of amyotrophic lateral sclerosis (ALS). MATERIALS AND METHODS: High-field-strength (1.5-T) MR images of 15 patients (seven men and eight women, aged 28-80 years) and 49 neurologically normal age-matched control patients were examined for T2 shortening in the motor cortex. In addition, brains of patients with ALS were examined at autopsy. RESULTS: The MR images of 14 of the 15 patients showed T2 shortening in precentral cortices, while the images of all but one of the control patients showed no such finding. In three of eight brains at autopsy, sections from the precentral cortex showed sparsely distributed, intensely stained astrocytes and macrophages. CONCLUSION: Abnormal iron deposition associated with the degenerative process could be the source of T2 shortening, which is a useful MR imaging finding in the diagnosis of ALS.

[MR imaging of amyotrophic lateral sclerosis].

Magnetic resonance imaging (MR imaging) provides a sensitive method for mapping the normal and pathological distribution of iron in the brain. High field strength MR imaging (1.5 T) was used to evaluate eight patients with amyotrophic lateral sclerosis (ALS) and 49 neurological normal control patients. All eight ALS patients showed decreased signal intensity in the motor cortex on T2-weighted images, while only one of the normal control patients showed this finding. The results suggested that the decreased signal intensity in the motor cortex in ALS was caused by the deposition of iron in this area.

MR imaging of malignant mesenchymal tumors of the liver.

Magnetic resonance (MR) features of five primary malignant mesenchymal neoplasms (plasmocytoma, leiomyosarcoma, undifferentiated sarcoma, epithelioid hemangioendothelioma, and angiosarcoma) of the liver were reported. All tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. No halo and intravenous extension were noted. A target appearance was revealed in epithelioid hemangioendothelioma. MR findings of angiosarcoma were essentially the same as those of cavernous hemangiomas (markedly hyperintense with hypointense linear septa on T2-weighted images). MR findings of these rare hepatic malignancies were nonspecific, although they were quite different from those of typical hepatocellular carcinomas. This study suggested that MR differentiation of primary hepatic mesenchymal tumors from other common benign and malignant neoplasms was difficult; however, the number of studied cases was limited.

[MR imaging of splenic masses].

It has been reported that MR imaging of the spleen is unsuccessful in detecting focal lesions because there is not a significant difference in relaxation times between most tumors and surrounding normal spleen. We reviewed the MR imaging of 15 patients (5 cysts, 2 abscesses, 1 hemangioma, 5 malignant lymphomas, 2 metastatic tumors). In all cases, the difference in signal intensities between splenic tissue and mass lesions permitted detection of splenic lesions on MR images. But, malignant lesions were less visible than benign lesions.