No abstract

For bacteria and bacteriophages, cell wall digestion by hydrolases is a very important event. We investigated one of the proteins involved in cell wall digestion, the yomI gene product (renamed CwlP). The gene is located in the SP-␤ prophage region of the Bacillus subtilis chromosome. Inspection of the Pfam database indicates that CwlP contains soluble lytic transglycosylase (SLT) and peptidase M23 domains, which are similar to Escherichia coli lytic transglycosylase Slt70, and the Staphylococcus aureus Gly-Gly endopeptidase LytM, respectively. The SLT domain of CwlP exhibits hydrolytic activity toward the B. subtilis cell wall; however, reverse phase (RP)-HPLC and mass spectrometry revealed that the CwlP-SLT domain has only muramidase activity. In addition, the peptidase M23 domain of CwlP exhibited hydrolytic activity and could cleave D-Ala-diaminopimelic acid cross-linkage, a property associated with DD-endopeptidases. Remarkably, the M23 domain of CwlP possessed a unique Zn 2؉ -independent endopeptidase activity; this contrasts with all other characterized M23 peptidases (and enzymes similar to CwlP), which are Zn 2؉ dependent. Both domains of CwlP could hydrolyze the peptidoglycan and cell wall of B. subtilis. However, the M23 domain digested neither the peptidoglycans nor the cell walls of S. aureus or Streptococcus thermophilus. The effect of defined point mutations in conserved amino acid residues of CwlP is also determined.The cycle of bacteriophage infection of microorganisms comprises adsorption, insertion of nucleic acids, production of bacteriophage nucleic acids and proteins, and finally, host cell lysis. The infection cycle follows a highly ordered sequence of events where cell wall hydrolases, encoded in bacteriophage genomes, are involved in adsorption to cell walls (first infection cycle) and host cell lysis (final infection cycle) (1).One of the best studied Gram-positive bacteria, Bacillus subtilis, has prophage-like elements including PBSX, skin, and SP-␤ (2). The SP-␤ prophage is the largest prophage-like element in B. subtilis (2). Inspection of the BSORF database indicates that the SP-␤ prophage chromosomal region contains 184 genes and one cell wall hydrolase called BlyA, which has been identified as an L-alanine amidase (3). Interestingly, the Pfam database predicts that another gene product, YomI (renamed CwlP (cell wall lytic enzyme related to phage)), has two cell wall hydrolase domains, a soluble lytic transglycosylase (SLT) 3 and peptidase M23 (Fig. 1). However, the function of the two domains (SLT and peptidase M23) remains unclear. BLAST searches of the BSORF and Pfam databases indicate that the SLT domain contains a soluble lytic transglycosylase and a muramidase, although the domain name is annotated "SLT." At present, lytic transglycosylases and muramidases cannot be differentiated using amino acid sequence similarity. The peptidase M23 domain has hydrolytic activity, enabling it to digest the Gly-Gly bond. It is also known that LytM in Staphylococcus aureus has a peptidase M2...

No abstract

There is a high diversity of bees in the tropics, including honey bees and stingless bees, which are the main sources for honey and other ecosystem services. In Indonesia, beekeeping practices have been developed for centuries, and they have been part of many cultural practices in many traditional communities. The objective of this research was to study the beekeeping status and managed bee diversity in Indonesia and to investigate beekeepers’ perspectives on the factors and obstacles related to beekeeping. Direct interview and online interview were conducted to gain data on bees and beekeepers. In total, 272 beekeepers were interviewed across 25 provinces. Samplings of honey bees and stingless bees were also done during direct interviews for further identification and, when possible, pollen identification. All data and specimens were then sent to IPB Bogor for compilation and identification. We recorded 22 species of bees, including 3 species of honey bees and 19 species of stingless bees, that are reared by Indonesian beekeepers, with Apis cerana and Tetragonula laeviceps as the most common species. Our research also found that the majority of beekeepers fall into the category of the younger generation (30–39 years old) with educational background mostly from senior high school. Based on the beekeepers’ perspectives, there are several obstacles to beekeeping, especially the occurrence of death of bee foragers attributed to climate, food source, and pesticides. In conclusion, there is a need to develop a strategy for beekeeping and bee conservation in Indonesia, especially for adaptation and mitigation from environmental changes with a particular focus on climate and land-use change.

Effects of mixed cropping and barrier crops on the population density and parasitism of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), were evaluated in field plots of cabbage grown in Bali, Indonesia. The densities of P. xylostella at larval and pupal stages, as well as the overall density at larval plus pupal stages, were significantly lower in cabbage/coriander mixed cropping subplots than in cabbage monoculture subplots. Parasitism of P. xylostella by the larval parasitoid Diadegma semiclausum (Hellen) (Hymenoptera: Ichneumonidae) was not significantly different between the mixed and monocultural cropping systems. These results do not support the so-called enemies hypothesis, but suggest that disruption of the host searching behavior of female moths by neighboring non-host plants is the mechanism behind the associational resistance observed in the coriander mixed cropping system. The inclusion of a Napier grass barrier between mixed crop and monoculture subplots did not affect the influence of mixed cropping on larval and pupal densities. Therefore, Napier grass, which is used locally as a fence for preventing livestock invasion of fields, would not obstruct the pest-reducing effect of coriander/cabbage mixed cropping.

No abstract

Banana bunchy top virus (BBTV) mostly infects Musa spp. which causes banana bunchy top disease (BBTD), the most devastating viral disease in banana cultivation all over the world. During field survey in Sekar Bumi Tropical Farm located in Kerta Village, 15 heliconia plant samples showed green streak on lamina leaves that similar to common BBTD symptoms were collected. Further research was then conducted to identify molecular characteristic of BBTD in heliconia showing green streak. Molecular identification was conducted using polymerase chain reaction (PCR). Specific primers to amplified DNA target were used in this study: mRep/F (5’-GCGTGAAACGCACAAAAGGCC-3’) and mRep/R (5’-GCATACGTTGTCAAACCTTCTCCTC-3’). The expected 240 bp fragment target of partial master replication (mRep) gene was successfully amplified from ten out of 15 samples. Sequence analysis confirmed that the symptomatic heliconia samples were infected with BBTV and falls into the same clade with BBTV from the Asian Group.

Stone leek leafminer Liriomyza Chinensis is an exotic pest that currently has become a major pest in onion plantings in the island of Bali. This study was conducted to determine the behavior of flight, population development and to analyze the level of attack of stone leek leafminer against five varieties of onion (Bima Brebes, Bauji, Tajuk, Probo and Bali Karet). The results showed that adult L. Chinensis has begun to invade the plant since the appearance of leaves of onion plants to the soil surface. The peak of the invasion occurs when the plant is 3 weeks after planting (WAP). While the most adult flight activity occurs at 08.00-11.00. The development of the adult population has begun to appear since 1 week and peaked at 3 WAP, then decreased to 5 WAP and rose again at 6 WAP then decreased to 8 weeks while the larval population began to monitor 3 WAP and peaked at 5 WAP and then decreased steadily to 8 WAP. The average percentage of stone leek leafminer attack against Bima Brebes varieties (12.91%), Bauji (9.68%), Tajuk (10.09%), Probo (9.96%) and Bali Karet (13.56%). Likewise, the average intensity of stone leek leafminer attack against Bima Brebes varieties (19.79%), Bauji (15.55%), Tajuk (16.80%), Probo (17.10%) and Bali Karet (20.20%). This shows that the five varieties of onion tested were susceptible to stone leek leafminer, but Bauji varieties tended to be more resistant to it.