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can protocol

can protocol
can protocol

BOSCH

CAN Specification

Version 2.0

1991, Robert Bosch GmbH, Postfach 30 02 40, D-70442 Stuttgart

BOSCH

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart Sep. 1991 page 1

Recital

The acceptance and introduction of serial communication to more and more applications has led to requirements that the assignment of message identifiers to communication functions be standardized for certain applications. These applications can be realized with CAN more comfortably, if the address range that originally has been defined by 11 identifier bits is enlarged

Therefore a second message format (’extended format’) is introduced that provides a larger address range defined by 29 bits. This will relieve the system designer from compromises with respect to defining well-structured naming schemes. Users of CAN who do not need the identifier range offered by the extended format, can rely on the conventional 11 bit identifier range (’standard format’) further on. In this case they can make use of the CAN implementations that are already available on the market, or of new controllers that implement both formats.

In order to distinguish standard and extended format the first reserved bit of the CAN message format, as it is defined in CAN Specification 1.2, is used. This is done in such a way that the message format in CAN Specification 1.2 is equivalent to the standard format and therefore is still valid. Furthermore, the extended format has been defined so that messages in standard format and extended format can coexist within the same network.

This CAN Specification consists of two parts, with

?Part A describing the CAN message format as it is defined in CAN Specification 1.2;?Part B describing both standard and extended message formats.

In order to be compatible with this CAN Specification 2.0 it is required that a CAN implementation be compatible with either Part A or Part B.

Note

CAN implementations that are designed according to part A of this or according to previous CAN Specifications, and CAN implementations that are designed according to part B of this specification can communicate with each other as long as it is not made use of the extended format.

CAN Specification 2.0

PART A

BOSCH

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Sep. 1991 Part A - page 3

1INTRODUCTION (4)

2BASIC CONCEPTS (5)

3MESSAGE TRANSFER (10)

3.1Frame Types (10)

3.1.1DATA FRAME (10)

3.1.2REMOTE FRAME (15)

3.1.3ERROR FRAME (16)

3.1.4OVERLOAD FRAME (17)

3.1.5INTERFRAME SPACING (18)

3.2Definition of TRANSMITTER/RECEIVER (20)

4MESSAGE VALIDATION (21)

5CODING (22)

6ERROR HANDLING (23)

6.1Error Detection (23)

6.2Error Signalling (23)

7FAULT CONFINEMENT (24)

8BIT TIMING REQUIREMENTS (27)

9INCREASING CAN OSCILLATOR TOLERANCE (31)

9.1Protocol Modifications (31)

Contents

BOSCH

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Sep. 1991 Part A - page 4

1 INTRODUCTION

The Controller Area Network (CAN) is a serial communications protocol which efficiently supports distributed realtime control with a very high level of security.

Its domain of application ranges from high speed networks to low cost multiplex wiring. In automotive electronics, engine control units, sensors, anti-skid-systems, etc. are connected using CAN with bitrates up to 1 Mbit/s. At the same time it is cost effective to build into vehicle body electronics, e.g. lamp clusters, electric windows etc. to replace the wiring harness otherwise required.

The intention of this specification is to achieve compatibility between any two CAN implementations. Compatibility, however, has different aspects regarding e.g. electrical features and the interpretation of data to be transferred. To achieve design transparency and implementation flexibility CAN has been subdivided into different layers.

?the (CAN-) object layer

?the (CAN-) transfer layer

?the physical layer

The object layer and the transfer layer comprise all services and functions of the data link layer defined by the ISO/OSI model. The scope of the object layer includes ?finding which messages are to be transmitted

?deciding which messages received by the transfer layer are actually to be used,?providing an interface to the application layer related hardware.

There is much freedom in defining object handling. The scope of the transfer layer mainly is the transfer protocol, i.e. controlling the framing, performing arbitration, error checking, error signalling and fault confinement. Within the transfer layer it is decided whether the bus is free for starting a new transmission or whether a reception is just starting. Also some general features of the bit timing are regarded as part of the transfer layer. It is in the nature of the transfer layer that there is no freedom for modifications.

The scope of the physical layer is the actual transfer of the bits between the different nodes with respect to all electrical properties. Within one network the physical layer, of course, has to be the same for all nodes. There may be, however, much freedom in selecting a physical layer.

The scope of this specification is to define the transfer layer and the consequences of the CAN protocol on the surrounding layers.

Introduction

2 BASIC CONCEPTS

CAN has the following properties

?prioritization of messages

?guarantee of latency times

?configuration flexibility

?multicast reception with time synchronization

?system wide data consistency

?multimaster

?error detection and signalling

?automatic retransmission of corrupted messages as soon as the bus is idle again ?distinction between temporary errors and permanent failures of nodes and autonomous switching off of defect nodes

Layered Structure of a CAN Node

Application Layer

Object Layer

- Message Filtering

- Message and Status Handling

Transfer Layer

- Fault Confinement

- Error Detection and Signalling

- Message Validation

- Acknowledgment

- Arbitration

- Message Framing

- Transfer Rate and Timing

Physical Layer

- Signal Level and Bit Representation

- Transmission Medium

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

?The Physical Layer defines how signals are actually transmitted. Within this specification the physical layer is not defined so as to allow transmission medium and signal level implementations to be optimized for their application.

?The Transfer Layer represents the kernel of the CAN protocol. It presents messages received to the object layer and accepts messages to be transmitted from the object layer. The transfer layer is responsible for bit timing and

synchronization, message framing, arbitration, acknowledgment, error detection and signalling, and fault confinement.

?The Object Layer is concerned with message filtering as well as status and message handling.

The scope of this specification is to define the transfer layer and the consequences of the CAN protocol on the surrounding layers.

Messages

Information on the bus is sent in fixed format messages of different but limited length (see section 3: Message Transfer). When the bus is free any connected unit may start to transmit a new message.

Information Routing

In CAN systems a CAN node does not make use of any information about the system configuration (e.g. station addresses). This has several important consequences.

System Flexibility: Nodes can be added to the CAN network without requiring any change in the software or hardware of any node and application layer.

Message Routing: The content of a message is named by an IDENTIFIER. The IDENTIFIER does not indicate the destination of the message, but describes the meaning of the data, so that all nodes in the network are able to decide by MESSAGE FILTERING whether the data is to be acted upon by them or not.

Multicast: As a consequence of the concept of MESSAGE FILTERING any number of nodes can receive and simultaneously act upon the same message.

Data Consistency: Within a CAN network it is guaranteed that a message is simultaneously accepted either by all nodes or by no node. Thus data consistency of a system is achieved by the concepts of multicast and by error handling.

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Bit rate

The speed of CAN may be different in different systems. However, in a given system the bitrate is uniform and fixed.

Priorities

The IDENTIFIER defines a static message priority during bus access.

Remote Data Request

By sending a REMOTE FRAME a node requiring data may request another node to send the corresponding DATA FRAME. The DATA FRAME and the corresponding REMOTE FRAME are named by the same IDENTIFIER.

Multimaster

When the bus is free any unit may start to transmit a message. The unit with the message of higher priority to be transmitted gains bus access.

Arbitration

Whenever the bus is free, any unit may start to transmit a message. If 2 or more units start transmitting messages at the same time, the bus access conflict is resolved by bitwise arbitration using the IDENTIFIER. The mechanism of arbitration guarantees that neither information nor time is lost. If a DATA FRAME and a REMOTE FRAME with the same IDENTIFIER are initiated at the same time, the DATA FRAME prevails over the REMOTE FRAME. During arbitration every transmitter compares the level of the bit transmitted with the level that is monitored on the bus. If these levels are equal the unit may continue to send. When a ’recessive’ level is sent and a ’dominant’ level is monitored (see Bus Values), the unit has lost arbitration and must withdraw without sending one more bit.

Safety

In order to achieve the utmost safety of data transfer, powerful measures for error detection, signalling and self-checking are implemented in every CAN node.

Error Detection

For detecting errors the following measures have been taken:

- Monitoring (transmitters compare the bit levels to be transmitted with the bit levels detected on the bus)

- Cyclic Redundancy Check

- Bit Stuffing

- Message Frame Check

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Performance of Error Detection

The error detection mechanisms have the following properties:

- all global errors are detected.

- all local errors at transmitters are detected.

- up to 5 randomly distributed errors in a message are detected.

- burst errors of length less than 15 in a message are detected.

- errors of any odd number in a message are detected.

Total residual error probability for undetected corrupted messages: less than

message error rate * 4.7 * 10-11.

Error Signalling and Recovery Time

Corrupted messages are flagged by any node detecting an error. Such messages are aborted and will be retransmitted automatically. The recovery time from detecting an error until the start of the next message is at most 29 bit times, if there is no further error.

Fault Confinement

CAN nodes are able to distinguish short disturbances from permanent failures. Defective nodes are switched off.

Connections

The CAN serial communication link is a bus to which a number of units may be connected. This number has no theoretical limit. Practically the total number of units will be limited by delay times and/or electrical loads on the bus line.

Single Channel

The bus consists of a single channel that carries bits. From this data resynchronization information can be derived. The way in which this channel is implemented is not fixed in this specification. E.g. single wire (plus ground), two differential wires, optical fibres, etc.

Bus values

The bus can have one of two complementary logical values: ’dominant’ or ’recessive’. During simultaneous transmission of ’dominant’ and ’recessive’ bits, the resulting bus value will be ’dominant’. For example, in case of a wired-AND implementation of the bus, the ’dominant’ level would be represented by a logical ’0’ and the ’recessive’ level by a logical ’1’. Physical states (e.g. electrical voltage, light) that represent the logical levels are not given in this specification.

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

BOSCH

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Sep. 1991 Part A - page 9

Acknowledgment

All receivers check the consistency of the message being received and will acknowledge a consistent message and flag an inconsistent message.

Sleep Mode / Wake-up

To reduce the system’s power consumption, a CAN-device may be set into sleep mode without any internal activity and with disconnected bus drivers. The sleep mode is finished with a wake-up by any bus activity or by internal conditions of the system. On wake-up, the internal activity is restarted, although the transfer layer will be waiting for the system’s oscillator to stabilize and it will then wait until it has synchronized itself to the bus activity (by checking for eleven consecutive ’recessive’ bits), before the bus drivers are set to "on-bus" again.

In order to wake up other nodes of the system, which are in sleep-mode, a special wake-up message with the dedicated, lowest possible IDENTIFIER (rrr rrrd rrrr; r =’recessive’ d = ’dominant’) may be used.

Basic Concepts

BOSCH

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart Sep. 1991

Part A - page 10 3 MESSAGE TRANSFER

3.1 Frame Types

Message transfer is manifested and controlled by four different frame types:

A DATA FRAME carries data from a transmitter to the receivers.

A REMOTE FRAME is transmitted by a bus unit to request the transmission of the DATA FRAME with the same IDENTIFIER.

An ERROR FRAME is transmitted by any unit on detecting a bus error.

An OVERLOAD FRAME is used to provide for an extra delay between the preceding and the succeeding DATA or REMOTE FRAMEs.

DATA FRAMEs and REMOTE FRAMEs are separated from preceding frames by an INTERFRAME SPACE.

3.1.1 DATA FRAME

A DATA FRAME is composed of seven different bit fields:

START OF FRAME, ARBITRATION FIELD, CONTROL FIELD, DATA FIELD, CRC FIELD, ACK FIELD, END OF FRAME. The DATA FIELD can be of length zero.

Interframe Space Interframe

Space

Start of Frame

Arbitration Field

Control Field

Data Field

CRC Field

ACK Field

End of Frame

or Overload Frame

DATA FRAME Message Transfer

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

START OF FRAME

marks the beginning of DATA FRAMES and REMOTE FRAMEs. It consists of a single ’dominant’ bit.

A station is only allowed to start transmission when the bus is idle (see BUS IDLE). All stations have to synchronize to the leading edge caused by START OF FRAME (see ’HARD SYNCHRONIZATION’) of the station starting transmission first.

ARBITRATION FIELD

The ARBITRATION FIELD consists of the IDENTIFIER and the RTR-BIT.

IDENTIFIER

The IDENTIFIER’s length is 11 bits. These bits are transmitted in the order from ID-10to ID-0. The least significant bit is ID-0. The 7 most significant bits (ID-10 - ID-4) must not be all ’recessive’.

RTR BIT

Remote Transmission Request BIT

In DATA FRAMEs the RTR BIT has to be ’dominant’. Within a REMOTE FRAME the RTR BIT has to be ’recessive’.

CONTROL FIELD

The CONTROL FIELD consists of six bits. It includes the DATA LENGTH CODE and two bits reserved for future expansion. The reserved bits have to be sent ’dominant’.Receivers accept ’dominant’ and ’recessive’ bits in all combinations.

DATA LENGTH CODE

The number of bytes in the DATA FIELD is indicated by the DATA LENGTH CODE.This DATA LENGTH CODE is 4 bits wide and is transmitted within the CONTROL FIELD.

Interframe Space Start of Frame Identifier

RTR Bit

Control Field

ARBITRATION FIELD

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Coding of the number of data bytes by the DATA LENGTH CODE

abbreviations: d ’dominant’

r ’recessive’

DATA FRAME: admissible numbers of data bytes: {0,1,....,7,8}.

Other values may not be used.

r1r0DLC3DLC2DLC1DLC0

or

CRC

Field Arbitration

Field Data

Field

CONTROL FIELD Data Length Code

reserved

bits 0

1

2

3

4

5

6

7

8d d d d d d d d r d d d d r r r r d d d r r d d r r d d r d r d r d r d

DLC3DLC2DLC1DLC0Number of Data

Bytes

Data Length Code

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

DATA FIELD

The DATA FIELD consists of the data to be transferred within a DATA FRAME. It can contain from 0 to 8 bytes, which each contain 8 bits which are transferred MSB first.CRC FIELD

contains the CRC SEQUENCE followed by a CRC DELIMITER.

CRC SEQUENCE

The frame check sequence is derived from a cyclic redundancy code best suited for frames with bit counts less than 127 bits (BCH Code).

In order to carry out the CRC calculation the polynomial to be divided is defined as the polynomial, the coefficients of which are given by the destuffed bit stream consisting of START OF FRAME, ARBITRATION FIELD, CONTROL FIELD, DATA FIELD (if present) and, for the 15 lowest coefficients, by 0. This polynomial is divided (the coefficients are calculated modulo-2) by the generator-polynomial:

X 15 + X 14 + X 10 + X 8 + X 7 + X 4 + X 3 + 1.

The remainder of this polynomial division is the CRC SEQUENCE transmitted over the bus. In order to implement this function, a 15 bit shift register CRC_RG(14:0) can be used. If NXTBIT denotes the next bit of the bit stream, given by the destuffed bit sequence from START OF FRAME until the end of the DATA FIELD, the CRC SEQUENCE is calculated as follows:

CRC_RG = 0;

// initialize shift register REPEAT

CRCNXT = NXTBIT EXOR CRC_RG(14);

CRC_RG(14:1) = CRC_RG(13:0);

// shift left by CRC_RG(0) = 0;// 1 position

Data

or

Control

Field CRC Sequence

CRC Delimiter

Ack Field

CRC FIELD

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

IF CRCNXT THEN

CRC_RG(14:0) = CRC_RG(14:0) EXOR (4599hex);

ENDIF

UNTIL (CRC SEQUENCE starts or there is an ERROR condition)

After the transmission / reception of the last bit of the DATA FIELD, CRC_RG contains the CRC sequence.

CRC DELIMITER

The CRC SEQUENCE is followed by the CRC DELIMITER which consists of a single ’recessive’ bit.

ACK FIELD

The ACK FIELD is two bits long and contains the ACK SLOT and the ACK DELIMITER.In the ACK FIELD the transmitting station sends two ’recessive’ bits.

A RECEIVER which has received a valid message correctly, reports this to the TRANSMITTER by sending a ’dominant’ bit during the ACK SLOT (it sends ’ACK’).

ACK SLOT

All stations having received the matching CRC SEQUENCE report this within the ACK SLOT by superscribing the ’recessive’ bit of the TRANSMITTER by a ’dominant’ bit.ACK DELIMITER

The ACK DELIMITER is the second bit of the ACK FIELD and has to be a ’recessive’bit. As a consequence, the ACK SLOT is surrounded by two ’recessive’ bits (CRC DELIMITER, ACK DELIMITER).

END OF FRAME

Each DATA FRAME and REMOTE FRAME is delimited by a flag sequence consisting of seven ’recessive’ bits.

CRC

Field ACK Slot ACK Delimiter

End of Frame

ACK FIELD

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

3.1.2 REMOTE FRAME A station acting as a RECEIVER for certain data can initiate the transmission of the respective data by its source node by sending a REMOTE FRAME.

A REMOTE FRAME is composed of six different bit fields:

START OF FRAME, ARBITRATION FIELD, CONTROL FIELD, CRC FIELD, ACK FIELD, END OF FRAME.

Contrary to DATA FRAMEs, the RTR bit of REMOTE FRAMEs is ’recessive’. There is no DATA FIELD, independent of the values of the DATA LENGTH CODE which may be signed any value within the admissible range 0...8. The value is the DATA LENGTH CODE of the corresponding DATA FRAME.

The polarity of the RTR bit indicates whether a transmitted frame is a DATA FRAME (RTR bit ’dominant’) or a REMOTE FRAME (RTR bit ’recessive’).

Inter

Space Inter Space

Start of Frame

Arbitration Field

Control Field

CRC Field

ACK Field

End of Frame

or

Overload

Frame

REMOTE FRAME Frame

Frame

BOSCH

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Sep. 1991Part A - page 16

3.1.3 ERROR FRAME The ERROR FRAME consists of two different fields. The first field is given by the superposition of ERROR FLAGs contributed from different stations. The following second field is the ERROR DELIMITER.

In order to terminate an ERROR FRAME correctly, an ’error passive’ node may need the bus to be ’bus idle’ for at least 3 bit times (if there is a local error at an ’error passive’ receiver). Therefore the bus should not be loaded to 100%.

ERROR FLAG

There are 2 forms of an ERROR FLAG: an ACTIVE ERROR FLAG and a PASSIVE ERROR FLAG.

1.

The ACTIVE ERROR FLAG consists of six consecutive ’dominant’ bits.2.The PASSIVE ERROR FLAG consists of six consecutive ’recessive’ bits unless it

is overwritten by ’dominant’ bits from other nodes.

An ’error active’ station detecting an error condition signals this by transmission of an ACTIVE ERROR FLAG. The ERROR FLAG’s form violates the law of bit stuffing (see CODING) applied to all fields from START OF FRAME to CRC DELIMITER or destroys the fixed form ACK FIELD or END OF FRAME field. As a consequence, all other stations detect an error condition and on their part start transmission of an ERROR FLAG. So the sequence of ’dominant’ bits which actually can be monitored on the bus results from a superposition of different ERROR FLAGs transmitted by individual stations. The total length of this sequence varies between a minimum of six and a maximum of twelve bits.

An ’error passive’ station detecting an error condition tries to signal this by transmission of a PASSIVE ERROR FLAG. The ’error passive’ station waits for six consecutive bits

Data

Frame Error Flag

Error Delimiter

Interframe Space or

ERROR FRAME Overload

Frame superposition of Error Flags Error Frame 本页已使用福昕阅读器进行编辑。

福昕软件(C)2005-2010,版权所有,

仅供试用。

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

of equal polarity, beginning at the start of the PASSIVE ERROR FLAG. The PASSIVE ERROR FLAG is complete when these 6 equal bits have been detected.

ERROR DELIMITER

The ERROR DELIMITER consists of eight ’recessive’ bits.

After transmission of an ERROR FLAG each station sends ’recessive’ bits and monitors the bus until it detects a ’recessive’ bit. Afterwards it starts transmitting seven more ’recessive’ bits.

3.1.4 OVERLOAD FRAME

The OVERLOAD FRAME contains the two bit fields OVERLOAD FLAG and OVERLOAD DELIMITER.

There are two kinds of OVERLOAD conditions, which both lead to the transmission of an OVERLOAD FLAG:

1.The internal conditions of a receiver, which requires a delay of the next DATA

FRAME or REMOTE FRAME.

2.

Detection of a ’dominant’ bit during INTERMISSION.The start of an OVERLOAD FRAME due to OVERLOAD condition 1 is only allowed to be started at the first bit time of an expected INTERMISSION, whereas OVERLOAD FRAMEs due to OVERLOAD condition 2 start one bit after detecting the ’dominant’ bit.

At most two OVERLOAD FRAMEs may be generated to delay the next DATA or REMOTE FRAME.

End of Frame or Overload Overload Delimiter

Inter Space or

OVERLOAD FRAME Overload

Frame superposition of

Overload Flags Flag

Frame

Error Delimiter or Overload Delimiter

OVERLOAD FLAG

consists of six ’dominant’ bits. The overall form corresponds to that of the ACTIVE ERROR FLAG.

The OVERLOAD FLAG’s form destroys the fixed form of the INTERMISSION field. As a consequence, all other stations also detect an OVERLOAD condition and on their part start transmission of an OVERLOAD FLAG. (In case that there is a ’dominant’ bit detected during the 3rd bit of INTERMISSION locally at some node, the other nodes will not interpret the OVERLOAD FLAG correctly, but interpret the first of these six ’dominant’ bits as START OF FRAME. The sixth ’dominant’ bit violates the rule of bit stuffing causing an error condition).

OVERLOAD DELIMITER

consists of eight ’recessive’ bits.

The OVERLOAD DELIMITER is of the same form as the ERROR DELIMITER. After transmission of an OVERLOAD FLAG the station monitors the bus until it detects a transition from a ’dominant’ to a ’recessive’ bit. At this point of time every bus station has finished sending its OVERLOAD FLAG and all stations start transmission of seven more ’recessive’ bits in coincidence.

3.1.5 INTERFRAME SPACING

DATA FRAMEs and REMOTE FRAMEs are separated from preceding frames whatever type they are (DATA FRAME, REMOTE FRAME, ERROR FRAME, OVERLOAD FRAME) by a bit field called INTERFRAME SPACE. In contrast, OVERLOAD FRAMEs and ERROR FRAMEs are not preceded by an INTERFRAME SPACE and multiple OVERLOAD FRAMEs are not separated by an INTERFRAME SPACE.

INTERFRAME SPACE

contains the bit fields INTERMISSION and BUS IDLE and, for ’error passive’ stations, which have been TRANSMITTER of the previous message, SUSPEND TRANSMISSION.

ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

BOSCH ROBERT BOSCH GmbH, Postfach 30 02 40, D-70442 Stuttgart

Sep. 1991

Part A - page 19

For stations which are not ’error passive’ or have been RECEIVER of the previous message:

For ’error passive’ stations which have been TRANSMITTER of the previous message:

INTERMISSION

consists of three ’recessive’ bits.

During INTERMISSION no station is allowed to start transmission of a DATA FRAME or REMOTE FRAME. The only action to be taken is signalling an OVERLOAD condition.

BUS IDLE

The period of BUS IDLE may be of arbitrary length. The bus is recognized to be free and any station having something to transmit can access the bus. A message, which is pending for transmission during the transmission of another message, is started in the first bit following INTERMISSION.

The detection of a ’dominant’ bit on the bus is interpreted as a START OF FRAME.SUSPEND TRANSMISSION

After an ’error passive’ station has transmitted a message, it sends eight ’recessive’bits following INTERMISSION, before starting to transmit a further message or recognizing the bus to be idle. If meanwhile a transmission (caused by another station)starts, the station will become receiver of this message.

Frame Bus Idle

INTERFRAME SPACE Intermission Frame

Frame Bus Idle

INTERFRAME SPACE Intermission Frame

Suspend Transmission

Interframe Space

流式protocol

收获P3代生长状态良好细胞,0.25%胰酶消化,4 ℃离心,1 000 r/min,5 min。 ↓ 用PBS(含1%BSA)清洗细胞3次,计数细胞。 ↓ 各管依次加入单克隆抗体CD29、CD34、CD45、CD90。 ↓ 同时每管样品设立同型阴性对照。 ↓ 避光冰上孵育45 min。 ↓ 用PBS(含1%BSA)洗涤细胞3次,以除去未结合抗体,用500 μL PBS(含1%BSA)重悬细胞,流式细胞仪进行检测分析。 (四个CD抗原分子,四个阴性对照,一个空白对照。九个EP管)细胞一定要足够量,一般要求1×106个细胞。对于直接标记单色样本,应该设置空白对照、阴性对照(同型抗体对照)和待测样本。对于直接标记多色样本,在单色基础上另加补偿对照。阴性对照的设置:在实验过程中,假设做直接标记法,可将实验组细胞,取一管,加上与实验抗体所标记的荧光颜色相同的同型对照来作为阴性对照。空白对照:即不进行任何标记的细胞。但是我们买的是pe和fitc荧光标记的抗体,那一管样品内可以同时加两中不同标记的抗体,那它们的同型对照怎么设置?我们的样品可以放在EP管里面吗?检测时,样品至少需要多少量? 取第3代第3~5d BMSCs,胰蛋白酶-EDTA消化成为单细胞悬液; ↓ PBS(1到2ml)洗三次,离心,1000rpm,5min弃液; ↓ 4%多聚甲醛1ml室温下固定40min,1000r/min,离心5min后弃去上清液 ↓ PBS(1到2ml)洗两次,离心,1000rpm,5min弃液; ↓ 分别加入500ul已经稀释的大鼠CD29、CD34、CD45及CD90单克隆抗体; ↓ 避光孵育30min ↓ 用PBS洗涤细胞两次,以除去未结合抗体; ↓ 用PBS重悬细胞,流式细胞仪进行检测分析。 PBS洗涤细胞的过程中细胞丢失?

植物(拟南芥水稻)原位杂交详细protocol试验方法

植物材料的固定、包埋和制片 一、植物材料的固定和包埋 在此过程应注意避免Rnase的污染。所使用的熔蜡管(管盖不能耐受180℃烘,只需高压湿热灭菌即可)、量筒、三角瓶和药勺均需180℃烘5小时以上。所用蒸馏水无需用DEPC处理。所固定的材料越小越好,尽可能切除多余的材料。材料取下后应立即固定。取材后若不能立即固定,则应置于冰上运输。配试剂前请计算一下所需用量,用多少配多少,节约试剂。 300 ml量为例) 1、先打开一个60℃左右的水浴锅。 2、在通风橱中往三角瓶中加入12 g多聚甲醛(终浓度为4%)。 3、用量筒配300 ml PBS缓冲液(30 ml 10×PBS+270 ml水),另加1粒NaOH,盖好锡 箔纸后,轻轻摇动,稍微溶化后置于水浴锅中溶解。 4、完全溶解后,取出,加0.1% Tween-20 (300 ul)和0.1% Triton(300 ul)混匀(包 埋水稻时还要再加3 ml 25%的戊二醛)。 5、置于冰上或4℃冰箱降至室温,然后用硫酸调pH 至7.0。 6、把配制好的甲醛溶液分装到小瓶中,(一般用10 ml的小瓶)。 7、分装好的甲醛溶液应放置在冰浴中当天使用。 二、固定材料 1、取植物新鲜材料,去除不需要的部分至适当大小。注意:所固定的材料越小越好, 尽可能去除无用多余的部分。 2、把取好材料放入冰浴的装有甲醛溶液的小瓶中。注意每瓶中的切块数:太多固定不 好;太少则浪费固定液(固定液:材料≥20:1)。 3、材料放入固定液后,应通过抽真空(1至数分钟,视具体情况而定:尽可能短时间, 以材料沉入固定液中为准),帮助固定液进入组织中,以达到迅速固定植物材料的目 的。抽气减压时,尽量不要使液体过分沸腾。抽真空时,材料一般在固定液中浮起; 抽完真空的材料应该沉入固定液中,有时可能要反复多次抽真空,直至材料沉没在 固定液中。一般抽真空多于5分钟大部份材料还不沉没在固定液中的情况极少见, 如果此情况发生,建议抽真空达10分钟后,继续做步骤4。 4、抽真空后需要更换一次新鲜的固定液。 5、更换新鲜固定液后,材料在4℃过夜。 注意:甲醛有剧毒,因此药品的称取和溶液的配置必须在通风橱中进行!多聚甲醛极易飞散;称取时通风橱可暂不抽风;要避免将多聚甲醛洒落在天平或台面上造成污染,如有洒落,要及 按以下序列对材料进行脱水(水为高压灭过菌的双蒸水)。 0.85% NaCl 冰浴,30 分钟 2、50%乙醇/0.85% NaCl 冰浴,5 小时 3、70%乙醇/0.85% NaCl 冰浴,5 小时 4、85%乙醇/0.85% NaCl 4℃,过夜 50%乙醇后,材料应开始脱色。 /水 4℃,5小时 2、100%乙醇 4℃,5小时 3、100%乙醇 4℃,过夜 注:第三天起,每个脱水步骤时间可延长至一天。两次100%乙醇脱水后,材料应为无色。

清华大学实验动物研究和使用计划(AnimalProtocol)(201312

清华大学实验动物研究及使用计划(Animal Protocol)(201312版) 此处供IACUC使用: 研究计划编号 批准日期 终止日期 1)为节省审批时间和节约纸张,请首先e-mail本申请书电子版至清华大学实验动物使用与管理委员会(IACUC)工 作邮箱(lac@https://www.wendangku.net/doc/8814968098.html,)。 2)接收后将由IACUC秘书进行格式审查,假如符合要求,将递交给IACUC委员会所有成员进行审阅。IACUC秘书将 收集修改意见反馈给申请者。时间间隔一般为2周。 3)研究计划被批准后,PI签字后正式生效。请递交一式一份纸质版到实验动物中心1182房间订购动物。 A.管理信息:□初次申请□3年复审,请填写已有的研究计划号:() 列出在本计划中所有动物实验操作人员: 注:职责可为:课题设计、主要操作、辅助操作、手术操作、小鼠管理等 列出每个人相对于职责,已有的实验经验和资格 B.研究或教学的目的: 以一般非生物医学背景人员为对象,简述研究目的,以及对人类或动物的健康与解决的科学问题。一般只需要以非科学术语描述做什么以及做这个实验的必要性。 C.危险试剂或感染性试剂: □本计划不使用任何有害物质 □本计划使用有害物质,假如使用 危险试剂的使用需要取得清华大学生物安全委员会的认可。危险试剂包括下列几个范畴: □1. 放射性性物质□2. 致癌物/致突变物□3. 感染物质□4. 重组DNA □5. 肿瘤等细胞系□6. 组织或抗血清□7.其他有害物质 1.请详细描述具体的试剂名称、拟使用剂量,以及给药或使用方式: 2. 请详细描述对人或动物的潜在毒性、并简述安全操作和处理受污染动物及材料的方法及程序:

AFLP实验流程protocol(精)

AFLP实验流程protocol Step1 DNA提取(DNA extraction) Using CTAB method (这个我们现在都是用试剂盒提取了,不知道你们用什么提取,还是发给你,AFLP对DNA纯度和浓度的要求很高,CTAB很难满足这个要求,尤其是纯度要 求) 1.裂解液的制备:检查水浴锅是否有水,打开设温65℃,将CTAB母液预热溶解,按照每 管1ml的体积取CTAB母液,加入3%PVP(即0.03g/管),加热溶解,使用前 ...加入1~2%β-巯基乙醇(即10~20μl/管) 2.取样:称取0.02~0.025g(即20~30mg)硅胶干燥的样品,放入fastprep管中,做好标 记。※NOTE:样品在放入管中时,挑取幼嫩的叶片,尽量不要将叶脉等维管组织放入,切误将一个管中的样品溅入另一个管中。 3.打碎:将称好的样品放入fastprep打碎机中打碎,speed 5.0 time 30s, 取出加入制备好的 CTAB裂解缓冲液800μl/管,(※NOTE:裂解液的体积应该在fastprep管的一半以上,注意盖好管冒,防止裂解液在打碎和裂解的时候溢出。),混匀,使裂解液和样品充分接触,再打一次speed 5.0 time 30s。 4.裂解:水浴65℃,1h,注意在裂解的过程中每隔10min要混匀一次,(※NOTE:越到 裂解的后期动作越要温和,防止DNA剪切破碎。) 5.抽提:取出水浴样品,冷却至室温 .....,加入-20℃等体积(800μl/管)氯仿:异戊醇(24: 1),手摇晃混合均匀 .......,离心:室温,12000r/min,10min。 6.再次抽提:取上层液体约550μl,(※NOTE:尽量少取,不要将杂质一并取出)转入 一个灭菌1.5ml离心管中,做好标记,加入等体积加入-20℃等体积(800μl/管)氯 仿:异戊醇(24:1),手摇晃混合均 ......匀.,离心:4℃,14000r/min,10min。 7.初沉:取上清约。。。μl,转入一个灭菌1.5ml离心管中,做好标记,加入4℃ 0.1倍 体积NaAc (3mol/L pH 5.2),-20℃ 0.6倍体积异丙醇,-20℃沉淀40min,离心:4℃,12000r/min,10min。 8.干燥:弃上清,用小枪头吸干,在超经工作台中倒置干燥40min。打开水浴锅37℃水 浴锅,预热TE。 9.除RNA: 10.抽提RNAse 11.再沉 12.洗涤 13.干燥 14.溶解 15.检测 Using 试剂盒

定点突变protocol

基因定点突变试剂盒 产品简介: 碧云天生产的基因定点突变试剂盒(Site-directed Gene Mutagenesis Kit)可 以用于点突变,多个邻近密码子的突变,单个或多个邻近密码子的缺失 (deletion)或插入(insertion)。 本试剂盒是一个利用目前最新的基因点突变技术设计而成的试剂盒。只 需通过基于PCR的突变质粒的合成,和基于Dpn I的模板质粒的消化,转 化培养以及后续的酶切或测序鉴定,即可得到预期的突变质粒(参考图 1)。累计操作时间不足2小时即可完成基因的定点突变。 参考图1,使用本试剂盒时需要先设计长度通常为30个碱基以上的互补的 两个引物,在引物中含有预期的突变位点。然后以待突变的质粒为模 板,用这两个引物进行PCR扩增反应。这样可以产生含有预期的突变位 点的双链质粒,但这个双链质粒中有两个nick位点。待突变的质粒通常来 源于大肠杆菌等细菌,在细菌中会被甲基化修饰,而在体外通过PCR扩 增得到的质粒不会被甲基化。这样用甲基化酶Dpn I处理,可以消化掉待 突变的质粒模板,而使通过PCR扩增出来的含有突变位点的质粒被选择 性地保留下来。这样把Dpn I处理过的产物转化细菌后,质粒中有两个 nick位点可以被大肠杆菌修复,得到的克隆就会含有预期的突变质粒了。 本试剂盒提供了DH5α甘油菌,可用于感受态细菌的制备。 本试剂盒共可以进行十次基因定点突变反应。图1. 基因定点突变试剂盒原理图 保存条件: -20℃保存,一年有效。 注意事项: 需自行配制LB液体培养基和LB平板以用于细菌的培养。 需自行设计和合成用于基因定点突变的引物。需自备用于细菌转化的试剂。 使用本试剂盒前请先阅读后面的常见问题。 为了您的安全和健康,请穿实验服并戴一次性手套操作。 使用说明: 1. 引物设计: 用于特定基因突变的引物需要单独设计,请参考如下一些基本原则进行设计: (1) 共需设计两条互补的引物。可以先集中设计一条,然后就可以得到互补的另一条引物。 (2) 引物的长度通常为25-45个碱基。 (3) 引物中突变位点任何一侧都必需满足 4X(GC碱基数)+2X(AT碱基数) ≥45。但引物也不宜过长,否则通常会形成非常 稳定的二级结构。通常把突变位点两侧的碱基数控制在15个左右,且使两侧按照上述计算得到的数值相近。 例如引物为agtcaggccaattcg aag cagtcgaattgccaag,其中蓝色的aag为突变位点,则

RNA提取protocol

TRIzol 提取RNA 实验试剂: TRIzol、氯仿、异丙醇、75%酒精、DEPC水 实验用具: 4℃离心机,1mL、200uL、100uL移液器,1.5mL、200uL EP管,一次性手套、口罩等 操作步骤 1. 样品处理 取新鲜或-70℃冻存小鼠视网膜尽量剪碎,每50-100 mg组织加入1 ml TRIzol,匀浆仪进行匀浆处理。(可先加200uLTRIzol直接用移液枪打碎视网膜,再加TRIzol至1mL) 可选步骤:当样品富含蛋白质,脂肪,多糖或是细胞外物质例如肌肉,脂肪组织和植物的块茎部分时可能需要一额外的分离步骤。匀浆化后在2~8°C的条件下以12,000×g的离心力离心10分钟,移除匀浆中不溶解的物质,余下的沉淀中包含有细胞外膜,多糖,以及高分子量DNA,而RNA存在于上清中。对于脂肪组织的样品中,大量的脂肪漂在最上层也应该除掉。吸取上清备用。 2. 将匀浆样品反复吹打几次,在室温条件下静置5min,使蛋白核酸复合物完全分离。 3. 向以上溶液中加入氯仿,每使用1ml TRIzon加入0.2ml氯仿,盖好管盖,剧烈振荡15秒,室温放置2-3min。 4. 4℃12,000 rpm离心15分钟,此时样品分成三层:红色有机相,中间层和上层无色水相,RNA主要在水相中,把水相(约600μl)转移到一个新的离心管(自备)中。 5. 在得到的水相溶液中加入0.5mL异丙醇(每使用1mLTRIzol加入0.5mL异丙醇),颠倒混匀,室温放置10分钟。 6. 4℃ 12,000 rpm离心10分钟,弃上清。 7. 加入75%乙醇(用无RNase的水配制)洗涤沉淀。每使用1 ml TRIzol用1 ml 75%乙醇对沉淀进行洗涤一次。 8. 4℃7500rpm离心5分钟,小心吸弃上清,注意不要吸弃RNA沉淀。 9. 室温放置5分钟,晾干。加入30-100 μl无RNase的水,充分溶解RNA(可55~60℃溶解10min),得到的RNA分装于200uL EP管中(每管10uL)。测浓度后保存在-70℃,防止降解。 注意:沉淀不要过分干燥,以免难于溶解。

免疫共沉淀(Co-IP)protocol

免疫共沉淀(Co-IP)Protocol 一、原理: 免疫共沉淀(Co-Immunoprecipitation)是以抗体和抗原之间的专一性作用为基础的用于研究蛋白质相互作用的经典方法。是确定两种蛋白质在完整细胞内生理性相互作用的有效方法。其原理是:当细胞在非变性条件下被裂解时,完整细胞内存在的许多蛋白质-蛋白质间的相互作用被保留了下来。如果用蛋白质X 的抗体免疫沉淀X,那么与X在体内结合的蛋白质Y也能沉淀下来。目前多用精制的prorein A预先结合固化在argarose的beads上,使之与含有抗原的溶液及抗体反应后,beads上的prorein A就能吸附抗原达到精制的目的。这种方法常用于测定两种目标蛋白质是否在体内结合;也可用于确定一种特定蛋白质的新的作用搭档。 其优点为:(1)相互作用的蛋白质都是经翻译后修饰的,处于天然状态;(2)蛋白的相互作用是在自然状态下进行的,可以避免人为的影响;(3)可以分离得到天然状态的相互作用蛋白复合物。缺点为:(1)可能检测不到低亲和力和瞬间的蛋白质-蛋白质相互作用;(2)两种蛋白质的结合可能不是直接结合,而可能有第三者在中间起桥梁作用;(3)必须在实验前预测目的蛋白是什么,以选择最后检测的抗体,所以,若预测不正确,实验就得不到结果,方法本身具有冒险性。 二、准备工作: 预冷PBS,RIPA Buffer,细胞刮子(用保鲜膜包好后,埋冰下),离心机 1. 用预冷的PBS洗涤细胞两次,最后一次吸干PBS; 2. 加入预冷的RIPA Buffer(1ml/107个细胞、10cm培养皿或150cm2培养瓶,0.5ml/5×106个细胞、6cm培养皿、75cm2培养瓶) 3. 用预冷的细胞刮子将细胞从培养皿或培养瓶上刮下,把悬液转到 1.5EP 管中,4℃,缓慢晃动15min(EP管插冰上,置水平摇床上) 4. 4℃,14000g离心15min,立即将上清转移到一个新的离心管中 5. 准备Protein A agarose,用PBS 洗两遍珠子,然后用PBS配制成50%浓度,建议减掉枪尖部分,避免在涉及琼脂糖珠的操作中破坏琼脂糖珠

Western-Blot-protocol实验步骤

Western Blot protocol 主要试剂及缓冲液的配制 1). 30%丙烯酰胺: 将29g丙烯酰胺和1g N,N’-亚甲双丙烯酰胺溶于总体积为100ml的水中。搅拌器帮助溶解,滤纸过滤除杂质,避光保存于4度冰箱。 2). 10% SDS: 称量10g十二烷基硫酸钠,加入80ml超纯水中,加热搅拌溶解,加水至100ml室温保存备用。 3).10x蛋白电泳缓冲液: 、188g甘氨酸、10gSDS、加水至1000ml 4).20×转膜缓冲液: Tris 29g,Glycine 144g,SDS 2g 加水定容至1000ml 配制1×转膜缓冲液200ml (甲醇 40ml,20×transfer buffer 10ml,H2O 150ml) 5). Tris :(注意温度对tris PH值的影响) g Tris 溶于80ml超纯水中,加浓盐酸调PH值,定容至100ml。 · 高温灭菌后室温保存。 6).1M Tris :

Tris 溶于80ml 超纯水,加浓盐酸调PH值,定容至100ml。 高温灭菌后室温保存。 7). 10×PBS: NaCl 80g,KCl 2g,,KH2PO4 ,用盐酸调PH至,加水定容至1000ml 8). 1xPBST% Tween 20): 10×PBS 100ml,H2O 900ml, Tween 20 50ul 9).10%(W/V)过硫酸铵: 临时配,过硫酸铵溶于1ml 超纯水,4度冰箱保存3天 10). 丽春红染液储存液%(W/V)丽春红,5%(V/V)乙酸): ,丽春红,冰醋酸2ml,超纯水 38ml 》 11). 封闭液: 5%(W/V)脱脂奶粉溶于1X PBST 中,使用时现配。 12) Stripping buffer (BME 800ul,SDS 2g,TRIS ,HCl调pH至,加水定容至100ml) 操作步骤 1.蛋白制备:10CM细胞平板,90%满度。弃培基,用5ml PBS清洗一遍, 加入1 ml PBS用细胞刮将细胞挂下,移入2 ml EP管中,(将平板

流式细胞仪Protocol

第一章流式细胞仪的结构和原理 第1节流式细胞术发展史 纵观历史,几乎没有哪一门科学技术象流式细胞术这样凝结了众多不同学术背景、不同科研领域科学家的心血。从流式细胞术的发明、改进、革新,到今天在各个领域应用的拓展,每一步都是诸如生物学、生物技术、计算机科学、流体力学、激光技术、高等数学、临床医学、分子生物学、有机化学和生物物理学等学科知识综合运用的结晶。现代流式细胞术更是由于结合了单克隆抗体技术、定量细胞化学技术和定量荧光细胞化学,使其在生物学、临床医学、药物学等等众多研究领域中的应用有了更加突飞猛进的发展。临床流式细胞术发展趋势可归纳为:①流式细胞仪从单纯大型仪器发展为适应各种实际应用的便携式、台式、高分辨率、高质量分选的研究型流式细胞仪;②对流式细胞术检测荧光参数,从采用荧光单色、双色分析发展为多色分析,目前最多可同时检测15 种荧光信号;③从检测参数的相对定量发展为绝对定量;④从检测参数的手动人工分析发展为计算机软件的自动分析;⑤所采用的荧光试剂,从非配套试剂发展为配套的试剂盒试剂。而这一切,就要求我们流式细胞仪使用者和科研人员一定要不断地有意识地学习上述各门学科知识,只有这样才能更好地将流式细胞术应用到生物医学的临床实践和基础科学研究工作中去。 流式细胞术的发展简史: 1930年 Caspersson 和 Thorell 开始致力于细胞的计数; 1934年 Moldaven 是世界上最早设想使细胞检测自动化的人,他试图用光电仪记录流过一根毛细管的细胞数量; 1936年 Caspersson等引入显微光度术; 1940年 Coons 提出用结合了荧光素的抗体去标记细胞内的特定蛋白; 1947年 Guclcer 运用层流和湍流原理研制烟雾微粒计数器; 1949年 Wallace Coulter 提出在悬液中计数粒子的方法并获得专利; 1950年 Caspersson用显微分光光度计的方法在紫外线(UV)和可见光光谱区检测细胞:1953年 Croslannd-Taylor应用分层鞘流原理,成功地设计红细胞光学自动计数器; 1953年Parker和Horst描述一种全血细胞计数器装置,成为流式细胞仪的雏形; 1954年 Beirne和Hutcheon发明光电粒子计数器; 1959年B型Coulter计数器问世; 1965年 Kamemtsky等提出两个设想,一是用分光光计定量细胞成份;二是结合测量值对细胞分类; 1967年 Kamemtsky和Melamed在Moldaven的方法基础上提出细胞分选的方法; 1969年Van Dilla,Fulwyler及其同事们在Los Alamos,NM(即现在的National Flow Cytometry Resource Labs),发明第一台荧光检测细胞计; 1972年 Herzenberg 研制出一个细胞分选器的改进型,能够检测出经荧光标记抗体染色的细胞的较弱的荧光信号; 1975年Kochler和Milstein提出了单克隆抗体技术,为细胞研究中大量的特异的免疫试剂的应用奠定了基础。 从此,大量厂家不断研制生产出各具特色的流式细胞仪,流式细胞术进入了一个空前飞速发展的时代。科学家们、仪器制造商们又纷纷将流式细胞仪的研究焦点转向染料的开发、细胞的制备方法和为提高电子信号的处理能力上来。进入21 世纪,流式细胞术作为一门生

实验方法(Protocol)的检索方法

实验方法(Protocol)的检索方法-来自《丁香园》来源:夏叶子的日志 找到一个合适的实验方法,对科学研究有着很重要的意义。对于多数常见的分子生物学方法,我们可以参考分子克隆搞定,但是有时一些特定的方法,就需要自己动手寻找。比如说,如果我要找到一个测定GTPase活性的方法,貌似分子克隆上就没有。这时,就需要用上一些必要的检索技巧。 方法1:https://www.wendangku.net/doc/8814968098.html,检索 检索式子:GTPase acitivity assay site:edu 这个检索式子中请注意三点:一是https://www.wendangku.net/doc/8814968098.html,而不是https://www.wendangku.net/doc/8814968098.html,,二是assay这个词的运用,许多paper中某个特定的实验方法多使用assay这个词,因此该词有助于快速从文献中捞取试验方法(如果搜索实验室网页建议用protocol这个词);其三,site:edu的限定,可以搜索到美国大学实验室网页上的提供此方法的链接。当然,你可以限定为site:https://www.wendangku.net/doc/8814968098.html,(英国大学), site:ac.jp(日本), site:fr(法国)。大家别小看这个定位式子,可以淘汰掉商业公司捆绑自己产品的一些所谓protocol。淘汰商业公司实验方法的另一个检索式子是:"https://www.wendangku.net/doc/8814968098.html,"。 方法2:杂志搞定 提供实验方法的网站很多,比如 Nature protocols Nature methods Nucleic Acids Research Methods 等等。这个我就不逐一介绍了。到这些杂志主页就可以搜索到。现在又出现一个视频化的杂志,即https://www.wendangku.net/doc/8814968098.html,/,专门用视频的方式介绍实验操作。由此联想到,某些比较抽象的或者没有接触过的实验,可以在youtube上搜索视频,更为直观。 方法3: 电子书搞定 很多出版社提供了丛书形式的试验方法,常见的有: Wiley出版社的Current protocols系列(https://www.wendangku.net/doc/8814968098.html,/browse/?ty pe=CURRENT_PROTOCOL) Springer出版社的Methods系列(原humana press所有),现在也称springer protocols (https://www.wendangku.net/doc/8814968098.html,/index.vm); Elsevier出版社也有Methods系列,著名的包括Methods in Enzymology,Methods in C ell Biology等(地址:https://www.wendangku.net/doc/8814968098.html,/science?_ob=BrowseListURL&_type =title&_title=M&content=journals&content=books&entitle=sub&entitle=nsub&_acct=C0 00050221&_version=1&_urlVersion=0&_userid=10&md5=48002dbf3641bac8f773ee39b e006ff7); 冷泉港出版社的Protocols系列(https://www.wendangku.net/doc/8814968098.html,/) 可喜的是,这些电子书大都可以检索到免费的。 比如说,到上述出版社的网页找到这篇文章:“Isolation of endocitic organelles by densit y gradient centrifugation”,我们看到,此文章属于“Methods in Molecular Biology”系列丛书中,“2D PAGE: Sample Preparation and Fractionation”这部分的内容。为此,我们在g oogle中输入:

亚细胞定位实验protocol

亚细胞定位 Confocus 一、实验材料 玻片,镊子,75%酒精,细胞转染用物品,PBS,4%多聚甲醛,Trixon-X-100,铝箔,摇床,DAPI染色液,荧光封片液,指甲油,载玻片,激光扫描共聚焦显微镜(型号:ZEISS LSM 510 META),光盘 二、实验原理 亚细胞定位是指某种蛋白或表达产物在细胞内的具体存在部位,如胞核,胞浆内,细胞膜或某一特定细胞器上存在。通常是将目的蛋白与报告基因(如绿色荧光蛋白基因EGFP、红色荧光蛋白基因Dsred等)融合表达,在激光共聚焦显微镜下观察荧光的表达部位从而致使目的蛋白在细胞内的定位。 DAPI,4,6-联脒-2-苯基吲哚,是一种标记细胞核的荧光染料,因其与dsDNA有高度的亲和力,与DNA结合后会发出强烈的荧光。 激光共聚焦扫描显微技术(Confocal laser scanning microscopy)是一种高分辨率的显微成像技术。普通的荧光光学显微镜在对较厚的标本(例如细胞)进行观察时,来自观察点邻近区域的荧光会对结构的分辨率形成较大的干扰。共聚焦显微技术的关键点在于,每次只对空间上的一个点(焦点)进行成像,再通过计算机控制的一点一点的扫描形成标本的二维或者三维图象。在此过程中,来自焦点以外的光信号不会对图像形成干扰,从而大大提高了显微图象的清晰度和细节分辨能力。 三、操作程序与结果判定(结合自己的经验将可能遇到的问题 及解决办法也列出) 1、细胞爬片的处理(24孔板) 细胞爬片可以买专门的爬片(一般直径1cm的正方形玻片正好适合24孔板的大小)用镊子夹取后在酒精灯上过火后轻轻放入细胞板内。此后再接入适量消化好的细胞。 爬片处理:将玻片放入小烧杯,再加浓硫酸处理。处理完后,用ddH20洗。再泡到75%酒精里。

蛋白纯化protocol

诱导表达 1、挑取含重组质粒的单菌落至5ml LB(含抗性)培养基中37℃过夜培养。 2、按1∶100比例稀释过夜菌,一般将50μl菌接种到含5ml LB(含抗性)培养基的5 ml试管中, 37 ℃震荡培养至OD600≌0.4-0.8(最好0.6,单抗大约需2-2.5 hr,双抗大约需3-3.5hr)。 3、取部分液体作为未诱导的对照组,余下的加入诱导剂至终浓度作为实验组,两组继续在合适温度下震荡培养4hr。 4、分别取菌体0.5 ml, 离心10000 g × 1 min收获沉淀,用40μl蛋白loading buffer重悬,混匀,煮沸5min。 5、离心10000 g × 5 min,取上清作为样品,可做SDS-PAGE等分析。蛋白质纯化 亲和层析 一、样品准备 1) 准备细胞,接种,诱导表达。对于实验室用的pET载体表达系列,在细胞OD600=0.4-0.8时,用IPTG诱导1-4小时,可以获得理想的表达效率。收集细胞,置于-20 ℃或立即进行步骤2操作。 2) 用Binding Buffer重悬清洗细胞,混匀,离心收集菌体。再加入1/20细胞生长体积的Binding Buffer,将菌体悬浮起来,混匀,冰上超声破碎细胞。 3) 10000 g,4 ℃离心20-30 min。取上清,置于冰上备用或-20度保存。

二、层析 1) 将处理好的NTA树脂装入合适的层析柱,将样品加到NTA层析柱中,流速控制在0.5-1 ml/min左右,收集流出部分,用于SDS/PAGE分析蛋白质的结合情况。 3) 用大约5倍柱体积的Binding Buffer洗,流速控制在0.5-1 ml/min左右,直到紫外监测数值基本无变化 4) 分别用2-5倍柱体积的梯度Elution Buffer洗脱,咪唑浓度分别为40mM,60mM,80mM,100mM,120mM,500mM。流速控制在0.5-1ml/min左右,收集洗脱液。待清楚纯化条件后,就可只使用2个咪唑梯度纯化。 5) 确定目标蛋白质在洗脱液中的分布情况。最为有效的方式是SDS/PAGE分析。 6) 目标蛋白质需要进一步纯化需要根据蛋白质的用途确定。纯化的目标蛋白质的保存条件需要根据蛋白质的性质和用途确定。 三、柱材料处理 1)用大约10倍柱体积的Strip Buffer洗,流速1 ml/min。 2)用大约10倍柱体积的ddWater洗,流速1 ml/min。 3)用大约10倍柱体积的Charge Buffer上镍,流速1 ml/min。4)用大约5倍柱体积的ddWater洗,流速1 ml/min。 5)用大约10倍柱体积的Binding Buffer平衡,流速1 ml/min。四、附件:溶液配方 Binding Buffer

springer protocol实验室指南

https://www.wendangku.net/doc/8814968098.html, Springer Protocols 實驗室指南 全世界內容最全面,並且經過同儕評閱的生命科學實驗室指南資料庫 7 超過18,000個實驗室指南, 每年新增2,000個 7 所有內容均源於實踐驗證, 包括:《分子生物學方法》 (Methods in Molecular Biology) 7 SpringerProtocols平臺提供 基於Web 2.0的合作研究功能

https://www.wendangku.net/doc/8814968098.html, Springer Protocols 實驗室指南: 廣泛的內容,可靠的來源,Springer Protocols是 生命科學研究者的無價資源。 出色的科學家一定會提出正確的問題,而且他們會通過設計恰當的實驗來獲得答案。這正是實驗室指南能夠給予幫助的地方。它可以提供確定的、可靠的和可信賴的實驗程式,而這些程式能夠讓使用者對實驗結果充滿信心。 —編輯 John M. Walker  《分子生物學方法》  (Methods in Molecular Biology)Springer Protocols包含18,000多個分子生物學 和生物醫學的實驗室指南,其中很多都是來 自經典的叢書系列,例如:《分子生物學方 法》(Methods in Molecular Biology)。 使用Protocol的研究者們希望得到可快速瀏 覽、值得信賴的線上資源。這些內容必須有很 高的學術認可,可以在實驗室“再現”。 我們鄭重向您推薦 Springer Protocols! Protocol 歷史 John M.Walker是Protocol的鼻祖,他是第一位通 過生物醫學實驗室指南(Protocol)按部就班地介 紹實驗方法,並使其成為標準的人。幾十年來, 分子生物學領域的學者們一直依賴著由Walker 博士編輯的實驗室研究指南:《分子生物學方 法》(Methods in Molecular Biology)。這些內容 經受了非常嚴格的實踐檢驗,倍受研究人員稱 讚。 Springer Protocols 現在,在https://www.wendangku.net/doc/8814968098.html,數据庫平臺和 https://www.wendangku.net/doc/8814968098.html,平臺上,您可以輕鬆訪問這些 由Walker博士編輯,實驗研究領域必不可少 的“處方”— Springer Protocols。 其他享有很高聲譽的Protocols包括: 7 Methods in Molecular Medicine 分子醫學方法 7 Methods in Biotechnology 生物技術方法 7 Methods in Pharmacology and Toxicology 藥理  學與毒物學方法 7 Neuromethods 神經方法 Springer Protocols 可以在 SpringerLink 的平臺瀏 覽。SpringerLink平臺收錄了1,700多種同行評 議的期刊,以及不斷擴充的電子書、電子叢 書、電子參考書和線上回溯性資料。Springer Protocols可以與這些內容合併檢索。 Springer Protocols 也可以作為一個獨立資料庫 瀏覽。https://www.wendangku.net/doc/8814968098.html, 平臺擁有web 2.0 特色,為生命科學研究者提供基於社區形式 的合作方式。使用者可以對自己關注的實驗 室指南添加注釋,使得同行從他的經驗中受 益。整個平臺內容框架設計出色,提供在實 驗室指南內、外部的快速導航,用戶可以便 捷地找到所需內容。由於這個網站內容來源 於Springer出版社,研究者可以信賴這些內容 的穩定性,並通過Springer出版社進一步瞭解 不斷擴充的內容。 產品特色一覽 7最大的線上實驗室指南的集合。超過18,000  種實驗室指南、每年遞增2,000種。包括當前  最新實驗室指南和可供選擇的版本。 什麼是實驗室指南(Protocol)? 實驗室指南:詳細、精確地實驗操作記錄,主要為生物化學、分子生物學、以及生物醫學等學科。 7 實驗室指南是一種標準化的,並可在實驗室再現的“配方”或“方法” 7 包括按部就班的操作步驟、實驗必需的原材料清單(原材料包括化學成分、硬體、軟體等  等) 7 包括注釋和提醒,提醒實驗員在實驗過程中需要注意的事項,以及如何解決問題 2

细胞迁移和浸润实验操作 protocol

For life science research only. Not for use in diagnostic procedures. System Technical Note No. 3 / February 2010 General Cell Migration Protocol Using the CIM-Plate 16

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