Two genes that encode Ca2+-dependent protein kinases are induced by drought and high-salt stresses in Arabidopsis thaliana

Two cDNA clones, AATCDPK1 and cATCDPK2, encoding Ca²⁺-dependent, calmodulin-independent protein kinases (CDPK) were cloned from Arabidopsis thaliana and their nucleotide sequences were determined. Northern blot analysis indicated that the mRNAs corresponding to the ATCDPK1 and ATCDPK2 genes are rapidly induced by drought and high-salt stress but not by low-temperature stress or heat stress. Treatment of Arabidopsis plants with exogenous abscisic acid (ABA) had no effect on the induction of ATCDPK1 or ATCDPK2. These findings suggest that a change in the osmotic potential of the environment can serve as a trigger for the induction of ATCDPK1 and ATCDPK2. Putative proteins encoded by ATCDPK1 and ATCDPK2 which contain open reading frames of 1479 and 1488 bp, respectively, are designated ATCDPK1 and ATCDPK2 and show 52% identity at the amino acid sequence level. ATCDPK1 and ATCDPK2 exhibit significant similarity to a soybean CDPK (51 % and 73%, respectively). Both proteins contain a catalytic domain that is typical of serine/threonine protein kinases and a regulatory domain that is homologous to the Ca²⁺-binding sites of calmodulin. Genomic Southern blot analysis suggests the existence of a few additional genes that are related to ATCDPK1 and ATCDPK2 in the Arabidopsis genome. The ATCDPK2 protein expressed in Escherichia coli was found to phosphorylate casein and myelin basic protein preferentially, relative to a histone substrate, and required Ca²⁺ for activation.     

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.     

Cloning and characterization of seven cDNAs for hyperosmolarity-responsive (HOR) genes of Saccharomyces cerevisiae

Yeast cells can respond and adapt to osmotic stress. In our attempt to clarify the molecular mechanisms of cellular responses to osmotic stress, we cloned seven cDNAs for hyperosmolarity-responsive (HOR) genes from Saccharomyces cerevisiae by a differential screening method. Structural analysis of the clones revealed that those designated HOR1, HORS, HOR4, HOR5 and HOR6 encoded glycerol-3-phosphate dehydrogenase (Gpd1p), glucokinase (Glklp), hexose transporter (Hxtlp), heat-shock protein 12 (Hsp12p) and Na⁺, K⁺, Li⁺-ATPase (Enalp), respectively. HOR2 and HOR7 corresponded to novel genes. Gpdlp is a key enzyme in the synthesis of glycerol, which is a major osmoprotectant in S. cerevisiae. Cloning of HOR1/GPD1 as a HOR gene indicates that the accumulation of glycerol in yeast cells under hyperosmotic stress is, at least in part, caused by an increase in the level of GPDH protein. We performed a series of Northern blot analyses using HOR cDNAs as probes and RNAs prepared from cells grown under various conditions and from various mutant cells. The results suggested that all the HOR genes are regulated by common signal transduction pathways. However, the fact that they exhibited certain distinct responses indicated that they might also be regulated by specific pathways in addition to the common pathways. Ca²⁺ seemed to be involved in the signaling systems. In addition, Hog1p, one of the MAP kinases in yeast, appeared to be involved in the regulation of expression of HOR genes, although its function seemed to be insufficient for the overall regulation of expression of these genes.     

Effect of High-intensity Light Given Prior to Low-temperature Treatment on the Long-day Flowering of Pharbitis nil

Pharbitis nil, strain Violet which had been exposed to high-intensitylight (18,000 lux at 23?C) for 7 days followed by a low-temperaturetreatment (13–14?C) for 7 days initiated flower buds evenunder continuous light, but plants given these treatments inreverse order failed to bud. Three days of high-intensity lightat 23?C was most effective in promoting the flower-inducingeffect of the subsequent low-temperature period. Six days oflow temperature following the 3-day high-intensity light periodinduced near-maximum flowering response. DCMU (5?10^–6M) given during the high-intensity light period inhibited flowering,but when given during or after the low-temperature period itwas ineffective. DCMU at the same concentration given before,during or after an inductive 16-hr dark period at 26?C did notinhibit flowering. Sucrose, ATP, NADPH and some other reducingagents tested did not nullify the DCMU effect nor substitutefor the effect of high-intensity light. But, the high-intensitylight effect could be substituted, at least partly, by 5-chlorosalicylicacid, 3,4-dichlorobenzoic acid and some other benzoic acid derivatives,which are highly effective in inducing long-day flowering inthe short-day plant, Lemna paucicostata. (Received October 20, 1981; Accepted February 3, 1982)