• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1576-1585
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• 2017

Yeasts, filamentous fungi, and bacteria colonize the surface of fermented sausages during the ripening process. The source of this microbiota is their surrounding environment, and is influenced by the maturing conditions and starter cultures. Debaryomyces hansenii was previously isolated from several dry-cured meat products and associated with the lipolytic and proteolytic changes that occur in these products, influencing their taste and flavor. Therefore, this study isolated the yeast microbiota present in the casing from different meat products ("lomo," "chorizo," and "$salchich{\acute{o}}n$") from the Valle de los Pedroches region in southern Spain. D. hansenii was by far the most abundant species in each product, as all 22 selected isolates were identified as D. hansenii by biochemical and/or molecular methods. In contrast, no yeasts were found in the meat batter. These data constitute the first study of the yeasts present in "lomo" sausages and particularly the highly appreciated Valle de los Pedroches "lomo" sausages. Furthermore, the resistance of these isolates to different pHs, temperatures, and saline stress was studied, together with their catabolic characteristics. Based on the results, certain isolates are proposed as valuable candidate starter cultures that could improve both the manufacture and the flavor of such dry-cured meat products, and provide an understanding of new mechanisms involved in stress tolerance. Applied medium-scale industrial tests are currently in progress.

• 미생물학회지
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• 제53권4호
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• pp.235-241
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• 2017

본 연구는 포도의 과피에서 분리한 효모 Pichia의 생리활성 증진효과를 연구하기 위한 것이다. 두 균주는 18S rRNA 염기서열분석에 근거하여 Pichia manshurica GU-3와 Pichia terricola GU-4로 각각 동정되었다. 주사전자현미경 분석을 통해 YPD 배지에서 배양한 두 분리세균은 세포표면에 출아와 출아흔적을 가지고 있었으며 전형적인 타원형을 보여주었다. 단일 및 혼합 Pichia 배양의 생리활성을 비교 관찰한 결과, 72시간 배양한 후, 혼합배양에서 tyrosinase억제, ACE 억제, 항산화 최대활성은 각각 81.7%, 45.9%, 42.7%로 나타났다. Superoxide dismutase-유사활성은 혼합배양에서 약 30%로 측정되었다. 이 연구를 통해서 혼합배양된 Pichia 종들은 생리활성을 증진시켰으며, 생리활성을 가지는 산물 개발의 가능성을 가지는 것으로 입증되었다.

• Applied Biological Chemistry
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• 제48권1호
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• pp.103-108
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• 2005

${\alpha}-Amylase$ 저해제는 소장에서 전분의 소화를 저해하여 포도당의 흡수를 지연시킴으로써 혈당 조절 목적으로 이용된다. 따라서 본 연구에서는 ${\alpha}-amylase$ 저해제를 탐색할 목적으로 국내 자생 목본류 약 1400여종의 70% ethanol 추출액을 대상으로 ${\alpha}-amylase$ 저해제 분포를 검색하였다. 수종의 목본류에서 ${\alpha}-amylase$ 저해제가 분포하고 있음이 확인되었으며, 그 중 활성이 비교적 높은 말채나무 기원의 저해제를 대상으로 연구를 진행하였다. 기원별 효소에 따른 저해 활성도를 살펴보면 salivary와 pancreatic ${\alpha}-amylase$, 미생물 기원의 ${\alpha}-glucosidase$에는 탁월한 저해 활성을 보인 반면 돼지 기원의 ${\alpha}-glucosidase$ 저해제에 대해서는 매우 낮은 저해 활성을 보였다. ${\alpha}-Amylase$와 ${\alpha}-glucosidase$의 kinetic을 분석하면 salivary와 pancreatic 두 효소에 모두 경쟁적 저해제로, 효모의 ${\alpha}-glucosidase$에는 비경쟁적과 반경쟁적의 혼합형 저해제로 나타났다. 또한 열과 산성에 대한 안정성을 확인한 결과 비교적 안정적인 것으로 나타났다. 본 추출물의 식이 섭취에 따른 혈당 강하 효과와 체중에 미치는 영향에서는 혈당과 체중 상승을 억제하는 효과가 확인되었고, mRNA수준에서 대퇴근 세포에 있어서 GLUT4의 발현이 증가됨을 확인하였다.

• 식물조직배양학회지
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• 제25권6호
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• pp.453-475
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• 1998

During the 100 years since the initial discovery of meiotic phenomenon many brilliant aspects have been elucidated, but further researches based on light microscopy alone as an experimental tool have been found to have some limits and shortcomings. By the use of electron microscopy and armed with the advanced knowledges on modern genetics and biochemistry it has been possible to applu molecular technology in gaining information on the detailed aspects of meiosis. As synapsis takes place, a three-layered proteinous structure called the synatonemal complex starts to form in the space between the homologous chromosomes. To be more precise, it begins to form along the paired chromosomes early in the prophase I of meiotic division. The mechanism that leads to precise point-by-point pairing between homologous chromocomes division. The mechamism that leads to precise point-by-point pairing between homologous chromosomes remains to be ascertained. Several items of information, however, suggest that chromsome alignment leading to synapsis may be mediated somehow by the nuclear membrane. Pachytene bivalents in eukaryotes are firmly attached to the inner niclear membrane at both termini. This attached begins with unpaired leptotene chromosomes that already have developed a lateral element. Once attached, the loptotene chromosomes begin to synapse. A number of different models have been proposed to account for genetic recombination via exchange between DNA strands following their breakage and subsequent reunion in new arrangement. One of the models accounting for molecular recombination leading to chromatid exchange and chiasma formation was first proposed in 1964 by Holliday, and 30 years later still a modified version of his model is favored. Nicks are made by endomuclease at corresponding sites on one strant of each DNA duplex in nonsister chromatid of a bivalent during prophase 1 of meiosis. The nicked strands loop-out and two strands reassociate into an exchanged arrangement, which is sealed by ligase. The remaining intact strand of each duplex is nicked at a site opposite the cross-over, and the exposed ends are digested by exonuclease action. Considerable progress has been made in recent years in the effort to define the molecular and organization features of the centromere region in the yeast chromosome. Centromere core region of the DNA duplex is flanked by 15 densely packed nucleosomes on ons side and by 3 packed nucleosomes on the other side, that is, 2000 bp on one side and 400 400 bp in the other side. All the telomeres of a given species share a common DNA sequence. Two ends of each chromosome are virtually identical. At the end of each chromosome there exist two kinds of DNA sequence" simple telpmeric sequences and telpmere-associated sequencies. Various studies of telomere replication, function, and behabior are now in progress, all greatly aided by molecular methods. During nuclear division in mitosis as well as in meiosis, the nucleili disappear by the time of metaphase and reappear during nuclear reorganizations in telophase. When telophase begins, small nucleoli form at the NOR of each nucleolar-organizing chromosome, enlarge, and fuse to form one or more large nucleoli. Nucleolus is a special structure attached top a specific nucleolar-organizing region located at a specific site of a particular chromosome. The nucleolus is a vertical factory for the synthesis of rRNAs and the assenbly of ribosome subunit precursors.sors.

• Advances in Traditional Medicine
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• 제5권3호
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• pp.216-230
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• 2005

Although the field of study in immune enhancing compounds is relatively new, natural products from plants represent a rich and promising source of novel molecules with immunomodulating properties, Microglial cells, the main immune effector cells of the brain, usually display a ramified morphology and low expression levels of immunologically relevant antigens such as MHC class I and class II. Since any compound which participates in activation of phagocytic cells contributes to the production of potentially toxic factors, the search for convenient in vitro test-systems and study of mechanisms of action of these agents are of great interest. Human blood polymorphonuclear (PMN) cells and primary microglial cells isolated from Sprague-Dawley rats were used as cellular screening tests for study of phagocytosis-stimulating action of immunomodulating agents. Numbers of phagocytic activity were evaluated by the phagocyte ingestion of yeast cells and NO-synthase activity, nitrite production, and nitroblue tetrazolium test were determined after phagocyte stimulation. It was possible to demonstrate that indexes of phagocytic activity can be used as quantitative indicators for measurement immunomodulating activity. As a positive control, Zymosan A-induced phagocytosis in both PMN cells and primary microglial cells was used. $IFN-{\gamma}$ (0.1 -1 U/ml) stimulated phagocytosis in PMN cells 1.2 times after 2 - 3 h incubation, although at higher concentrations (10 - 100 U/ml) it strongly inhibited phagocytosis. In a similar way, at higher concentrations, $IFN-{\gamma}$ (100 - 500 U/ml) suppressed phagocytosis in zymosan-A stimulated microglial cells. When Polypodium leucotomus, cambricum and vulgare extracts were tested alone, increased levels of phagocytosis were observed in PMN. In addition, microglial cells showed both increased phagocytosis and MHC class-II antigen expressions. Surprisingly, when PMN and microglia were treated with a combination of Polypodium and $IFN-{\gamma}$, phagocytosis was not inhibited. We did not find changes in NO-synthase activity and nitrite production in both microglia and PMN cells activated by different immunomodulating agents. These results indicate that primary microglial cell cultures as well as human PMN cells can provide reproducible quantitative results in screening phagocytic activity of different immunoactive compounds. Furthermore, both inhibitory or activation mechanisms might be studied using these in vitro experimental approaches.