Cyclization reaction catalyzed by branching enzyme.

The action of branching enzyme (EC 2.4.l.l8) from Bacillus stearothermophilus on amylose was analyzed. The enzyme reduced the molecular size of amylose without increasing the reducing power. This result could not be explained by the normal branching reaction model. When the product was treated with glucoamylase (an exo++-type amylase), a resistant component remained. The glucoamylase-resistant component was easily digested by an endo-type alpha-amylase or by isoamylase plus glucoamylase. These results suggested that the glucoamylase-resistant component was a cyclic glucan composed of alpha-1,4- and alpha-l,6-glucosidic linkages. In other words, it was suggested that branching enzyme catalyzed cyclization of the alpha-l,4-glucan chain of the amylose molecule to form an alpha-l,6-glucosidic linkage, thereby forming two smaller molecules. Mass spectrometry also supported the cyclic nature of the product.     

Cloning and Characterization of Two Novel Human cDNAs (NELL1 and NELL2) Encoding Proteins with Six EGF-like Repeats

From a human fetal-brain cDNA library we isolated two novel genes encoding peptides containing six EGF-like repeats. Both showed significant homologies with nel, a gene strongly expressed in neural tissues of chicken. The cDNAs, designated NELL1 (nel-like, type 1) and NELL2 (nel-like, type 2), contained open reading frames encoding 810 and 816 amino acids, respectively. NELL2 is strongly expressed in brain of adult and fetus but only weakly in fetal kidney. NELL1 and NELL2 were mapped by FISH to chromosomal bands 11p15.1–p15.2 and 12q13.11–q13.12, respectively.     

Structure and Chromosomal Assignment of the Human S1-5 Gene (FBNL) That Is Highly Homologous to Fibrillin

The human S1-5 gene (fibrillin-like; FBNL) was originally isolated from a subtractively enriched cDNA library established from a subject with Werner syndrome (WS). We isolated genomic clones containing the entire S1-5 gene and determined its genomic structure including the exon–intron organization. The gene spanned approximately 18 kb of genomic DNA and consisted of 12 exons. Its expression was abundant in all tissues examined except brain and peripheral leukocytes, where it was undetectable. In addition, we have mapped S1-5 by fluorescencein situhybridization to chromosome 2p16, a position that excludes it as a candidate for WS. Our data should facilitate an understanding of the function and regulation of S1-5 in human tissues.     

Isolation of Serratia marcescens mutants which could overproduce and excrete Escherichia coli alkaline phosphatase and beta-lactamase

Serratia marcescens mutants, which excrete Escherichia coli alkaline phosphatase (APase) encoded by the plasmid-bearing phoA gene, were isolated after mutagenesis by N-methyl--nitro-N-nitrosoguanidine. These mutants produced two to four times as much APase as did the parent strain under a phosphate-limiting condition, and more than 70% of the enzyme was released into the culture medium. In addition, overproduction and excretion of beta-lactamase was observed in these mutants.     

Effect of temperature and growth phase on fatty acid composition of the psychrophilic Vibrio sp. strain no. 5710

Abstract The cellular fatty acid composition of the psychrophilic Vibrio sp. strain No. 5710 isolated from a deep-sea sediment sample was analyzed. The presence of docosahexaenoic acid (22:6) was demonstrated as found previously in other deep-sea bacteria, and the relative amount of 22:6 decreased as the growth temperature increased. A temperature shift from 10°C to 0°C resulted in a relative increase of 22:6, and an opposite shift led to a decrease. In addition, hexadecanoic acid (16:0) was found to increase as the growth temperature increased. Therefore, it is suggested that the adaptation of 5710 to the growth temperature was carried out by the changes in the relative amounts of 22:6 and 16:0. When 5710 was grown at low temperature, it increased the relative amount of 22:6 presumably to maintain membrane fluidity at that temperature. In contrast, 5710 grown at high temperature probably maintained the membrane fluidity by increasing the amount of a saturated fatty acid, 16:0. Furthermore, observation of the fatty acid compositions at mid-exponential phase and early stationary phase revealed the proportions of several fatty acids, including a major fatty acid, 9- cis -hexadecenoic acid (16:1c, palmitoleic acid), were affected by the growth phase which may be due to the physiological difference between the growth phases.     

Presymptomatic direct detection of adenomatous polyposis coli (APC) gene mutations in familial adenomatous polyposis

The recent identification of the familial adenomatous polyposis (FAP) gene (designated as APC) enables conclusive genetic testing of at-risk family members for the specific mutation in families in which the germline gene mutation has been characterized. Presymptomatic molecular diagnosis of FAP was performed by direct direction of mutations in lymphocyte DNA in four families. Each of the families has a different mutation of the APC gene. Twenty-seven offspring of affected individuals (a priori risk of 50%) were tested. Ten of the 27 had already developed clinical features of FAP. Of the remaining seventeen, two had had a negative colon exam at an early age, and nine had never had colon exams (mean age, 12.1±3.1 SD years). Six children from this group (54%) were found to carry their affected parent's mutation. No change in the conventional FAP colon screening regimen is recommended for these children. In contrast, when direct tests indicate that an individual does not have the FAP mutation, we recommended that screening be decreased. Reduction of uncertainty for at-risk FAP family members is an important benefit of genetic testing.     

The second phantom aquatic leaf beetle in Japan: Macroplea mutica rediscovery in the wetlands (Coleoptera: Chrysomelidae)

Wetland biodiversity is currently declining on a global scale. Wetland biodiversity understanding is critical for determining the wetlands' conservation value. In this study, Macroplea Samouelle, 1819 (Coleoptera: Chrysomelidae) was discovered in Aomori Prefecture, Honshu Island, Japan. Only two Macroplea species have been recorded in Japan, M. japana (Jacoby, 1885) and M. mutica (Fabricius, 1792). Macroplea japana had been unrecorded for 60 years before being rediscovered in Honshu Island in 2022, and a single adult M. mutica female was discovered in Hokkaido Prefecture in 2003. The discovered individuals were concluded to be M. mutica based on morphological and molecular analyses. Although morphological differences were observed with the Eurasian M. mutica individuals, the male genitalia was nearly identical to M. mutica. For the molecular phylogenetic analysis based on COI and 28S sequences, Macroplea individuals in Japan were clustered with M. mutica on the Eurasian Continent. This is the first record of this species on Honshu Island (and the second in Japan), as well as the first record of adult males. This species would require conservation policies and additional distributional surveys.